NAP · Evidence & methodology
How NAP is grounded.
NAP is a browser-based teaching simulator, calibrated to what makes a lesson land rather than to perfect realism.
The professional sources on this page informed the design of its simulated physiology, teaching defaults, dynamics, morphologies and monitor behaviours. The simulation-education evidence below explains why calibrating fidelity to the learning objective is the right target.
This is the evidence base behind those choices, presented so educators and institutions can see what each source did, and did not, establish.
Scope and claim boundary
These sources do not establish that NAP is clinically validated, diagnostically accurate, equivalent to a real monitor, or suitable for patient care. NAP is a teaching simulator, not a medical device or clinical decision-support system.
A citation means a source informed a design choice; it does not mean the source endorses NAP. Every module-level fidelity claim remains gated on independent external clinical face-validation, a separate and still-open step.
Fidelity serves learning.
NAP treats fidelity as a means, not an end: it aims to match the learning objective, not maximum engineering resemblance to a particular patient, monitor brand or whole clinical room.
- The target: recognisable monitor behaviour, the salient physiological relationships and instructor control.
- The simulation-education literature does not make fidelity a simple ladder. Added realism helps when the objective needs it; irrelevant complexity can use up attention and bury the very cue being taught.
- Simplify to teach, never to mislead. The monitor-only scope, instructor-authored physiology and clamp-don’t-evolve behaviour are deliberate instructional choices.
- A design target, not validation. This rationale does not, on its own, validate clinical accuracy or unlock any module’s fidelity claim.
Hamstra et al., 2014 — Reconsidering fidelity in simulation-based training
The distinction between physical resemblance and functional task alignment: matching realism to the applied learning context, not to a specific device.
Norman, Dore and Grierson, 2012 — The minimal relationship between simulation fidelity and transfer of learning
Across the reviewed direct comparisons, higher-fidelity simulation was rarely superior to lower-fidelity: there is no simple “more realism, more learning” rule.
Dieckmann, Gaba and Rall, 2007 — Deepening the theoretical foundations of patient simulation as social practice
Goal-oriented matching of realism to the desired outcome, and the recognition that more physical realism does not uniformly improve learning.
Cook et al., 2013 — Comparative effectiveness of instructional design features in simulation-based education
The weight of instructional design (feedback, interactivity, practice and difficulty) over technology or resemblance alone.
Issenberg et al., 2005 — Features and uses of high-fidelity medical simulations that lead to effective learning
The conditions under which simulation supports learning: feedback, repetitive practice, curriculum integration, appropriate difficulty and explicit outcomes.
Rogers and Franklin, 2021 — Cognitive load in simulation-based learning experiences: an integrative review
Why extraneous load matters: unnecessary fidelity, complexity and distraction can crowd out the very cue being taught.
Society for Simulation in Healthcare — Simulation Dictionary (3rd ed.) and Accreditation Standards
The functional-versus-physical fidelity vocabulary, and the standard that modality and realism should meet the learning objectives: higher fidelity is not required for its own sake.
INACSL Standards Committee, 2021 — Healthcare Simulation Standards of Best Practice: Simulation Design
Purposeful simulation design that starts from identified objectives and optimises achievement of the expected outcomes.
Sweller, van Merriënboer and Paas, 2019 — Cognitive architecture and instructional design: 20 years later
Why guidance beats unassisted discovery for novices (the worked-example and guidance-fading effects): novices learn more from studying a guided solution than from searching for it, and guidance is faded only as expertise grows.
The learning-science rationale for NAP being instructor-driven, not self-directed.
INACSL Standards Committee, 2025 — Healthcare Simulation Standards of Best Practice: Facilitation (Clin Simul Nurs 105:101776)
Facilitation as a distinct, standards-recognised practice: “the structure and process necessary to effectively conduct simulated-based experiences”, with a facilitator who “directs the learning experience” and delivers cues toward the expected outcomes.
Grounds NAP’s instructor-driven model: NAP is the instrument a facilitator uses, not a facilitator itself.
DiGregorio et al., 2025 — The impact of simulation facilitation on learning outcomes: a systematic review
A recent synthesis of four studies in which facilitated simulation went with positive learning outcomes.
Directional support, not an effect size or a comparison against unfacilitated simulation; cited with the review’s own caveat that the small, heterogeneous evidence base limits pooling and generalisation.
How NAP uses evidence
Evidence review, implementation verification and external face-validation are separate gates. Matching a cited range or passing a code test does not demonstrate clinical realism. NAP uses evidence in four bounded ways.
- 01
Concept selection
Guidelines identify the rhythms, states, device interactions and observable relationships worth teaching.
- 02
Directional grounding
Primary literature informs whether simulated variables should rise, fall, equalise, vary with respiration or change morphology together.
- 03
Starting references
Published bands and conventions provide candidate defaults and soft plausibility fingerprints. A green test is not clinical validation.
- 04
Explicit limits
Sources also show what a monitor-only simulator cannot represent: neurological findings, laboratory criteria, clinical context or proprietary algorithms.
The evidence, by module
Grouped as NAP’s modules are built. Each group opens to its full source list; every link is the real, verified reference behind that design area.
Base monitor
Vital signs, rhythms, respiration, arrest and perfusion: the recognisable direction and relationships used in teaching scenarios, not universal “typical patient” values.
Validation status
Guideline-grounded · descriptiveWhat this covers
Blood pressure
When the two blood pressures are moved together, they follow a curve rather than a fixed ratio.
- The gap widens as the systolic rises, the way stiffer arteries behave with age. The curve differs for a child.
- The instructor can always unlink them and set any pair.
Details
- Why unlinking is necessary, beyond merely permitted: two patients with the same systolic can genuinely need very different diastolics.
Pulse rate, and the HR–PR difference
The monitor shows a pleth-derived pulse rate beside SpO₂, counted from the simulated pleth pulses NAP detects.
- It can differ from the ECG heart rate. In ventricular bigeminy it reads about half, because the early beats do not eject; in pulseless electrical activity it blanks entirely.
- The HR–PR difference resembles a pulse deficit. NAP renders it but does not diagnose or label it, and makes no claim to a validated pulse-deficit magnitude.
Whether a beat makes a pulse
A beat’s pulse is judged against the heart’s own expected cycle, not a fixed interval: a beat is weak because it arrived early, not because the patient is fast.
- A sustained fast rhythm keeps a smaller but real pulse.
- A markedly premature beat, as in bigeminy, may eject too little to register.
Details
- In keeping with reports of adults paced at 175/min sustaining an arterial trace, and of infants remaining asymptomatic in supraventricular tachycardia at rates near 300 (both cited below).
One circulation judgement feeds every signal
Whether a beat perfuses is decided once, per beat, and every pulse-derived signal reads that same judgement.
- Those signals: the oxygen saturation, the pleth, the pulse rate, the blood pressure, and whether the patient breathes spontaneously at all.
- They move together, as at the bedside: a pacer that gains capture restores them all at once; a rhythm that loses circulation blanks them together.
- The deliberate exception is agonal breathing, which still gasps: agonal respiration is brainstem-driven and is one of the things an arrest is recognised by.
- NAP renders the coherence; it does not evolve the patient. The instructor still sets what the patient is doing.
During chest compressions
During chest compressions the pulse tone is silenced and the pulse rate blanks.
- ASYSTOLE, VF and VT alarms are withheld during compressions, with a low-priority “CANNOT ANALYSE ECG” notice.
- When compressions stop, the monitor judges the current rhythm straight away. That is a deliberate simplification for teaching: NAP does not wait through a rhythm-detection window.
Details
- Why the pulse rate blanks: a pulse oximeter cannot separate a returning spontaneous pulse from the compression signal.
- Resuscitation guidance recognises return of circulation by means other than the oximeter: a rise in end-tidal CO₂, an arterial trace, or a pulse check at the rhythm check.
What the thresholds rest on
The shapes of these relationships are drawn from published work; the specific thresholds are documented teaching values, not validated measurements.
Drifts: slow trends set by the instructor
A drift takes one vital to the instructor’s target over the time they pick, along the shape they pick, then holds it there.
- The instructor sets every target; NAP only suggests a first one. It adds no compensation: BP falling while HR climbs is two drifts, both set by hand.
- Three shapes, no settings. Steady: the same change every second. Fast, then settling: the shape of a response to treatment. Steady, then sudden: a number that looks safe, then breaks away. The instructor picks one; NAP never picks for them.
- Time is compressed on purpose. A drift takes 1 min to 15 min; the pace is a teaching choice, not a model of how fast a patient changes.
- A scenario step leaves a drift running unless the scenario changes that vital at that step; then the drift carries on from the step’s value to the same target, as after a change by hand.
- Starting or restarting a scenario, a whole-patient preset, an arrest rhythm or a lost pulse stops every drift. The new picture is the instructor’s, and no drift carries across it.
Grounded in 22 sources
US National Center for Health Statistics, 2022 — NHAMCS emergency-department visit estimates
Prevalence rationale for including common chest-pain and dyspnoea presentations in the scenario coverage map.
Franklin et al., 1997 — Hemodynamic patterns of age-related changes in blood pressure (Framingham Heart Study)
That systolic and diastolic do not move in proportion: with age the diastolic falls while the gap between the two widens. This is the shape behind linking the two pressures along a curve.
SHEP Cooperative Research Group, 1991 — Prevention of stroke in older persons with isolated systolic hypertension
A reference pair at the top of the range (mean entry pressure 170/77), used as a landmark so a high systolic does not drag the diastolic up with it.
Beckett et al. for the HYVET Study Group, 2008 — Treatment of hypertension in patients 80 years of age or older
A second, independent landmark (173/91) in a group not selected on diastolic, so the wide gap belongs to the age group, not to the entry criteria.
Hamdan, Zagrodzky, Page, Wasmund, Sheehan, Adamson, Joglar and Smith, 2001 — Effect of P-wave timing during supraventricular tachycardia on the hemodynamic and sympathetic neural response (Circulation 2001;103(1):96–101)
Conscious adults paced at 175/min in three-minute runs kept a recorded arterial pressure, with an abrupt fall in blood pressure: a fast rhythm costs pressure, which the instructor authors, rather than the pulse.
Sreeram and Wren, 1990 — Supraventricular tachycardia in infants: response to initial treatment (Arch Dis Child 1990;65(1):127–9)
Infants presenting in supraventricular tachycardia at 215–315/min (mean 292), seven of 29 free of symptoms: an infant’s fast rhythm keeps a pulse.
American Heart Association, 2025 — Adult advanced life support
Shockable versus non-shockable arrest behaviour, CPR/capnography cues, reversible-cause coverage and ROSC directionality.
Resuscitation Council UK, 2025 — Special circumstances guidelines
Tension-pneumothorax and other reversible-cause recognition context.
World Allergy Organization, 2020 — Anaphylaxis guidance
Circulatory and respiratory direction of the anaphylaxis teaching state.
SCCM / ESICM, 2026 — Surviving Sepsis Campaign guidelines
Low-perfusion / MAP emphasis in the sepsis scenario.
Rossaint et al., 2023 — European guideline on major bleeding and coagulopathy after trauma (6th ed.)
Haemorrhagic-shock and major-trauma perfusion direction, and the distinction between a resuscitation target and a presenting value.
NICE, 2016 (updated) — Major trauma: assessment and initial management (NG39)
Urgent recognition and haemorrhage-control context for tension pneumothorax and major trauma.
ADA / EASD / JBDS / AACE / DTS, 2024 — Hyperglycaemic crises in adults: consensus report
DKA case definition; prevented an obsolete glucose threshold being presented as current.
SRLF / SFMU, 2024 — Oxygen therapy in acute hypoxaemic respiratory failure
The hypoxaemic-respiratory-failure archetype.
A monitor without blood gas cannot represent the whole syndrome.
BTS / SIGN, 2024 (corrected 2025) — SIGN 158: British guideline on the management of asthma
Recognisable severe-asthma vital-sign direction and deterioration cues. The 2024 joint BTS/NICE/SIGN guideline covers diagnosis and chronic asthma; acute asthma stays in SIGN 158.
Global Initiative for Asthma, 2026 — Global strategy for asthma management
Severe exacerbation and exhaustion context used alongside BTS/SIGN.
World Health Organization, 2025 — Opioid overdose fact sheet
Respiratory depression and loss of consciousness as the central monitor lesson in opioid overdose.
World Health Organization, 2011 — IMAI district clinician manual
Respiratory-arrest escalation and supportive-monitoring context for poisoning scenarios.
AAPCC consensus panel, 2007 — Tricyclic antidepressant poisoning out-of-hospital guideline
Importance of QRS morphology and haemodynamic compromise in the TCA teaching case.
ACC / AHA, 2022 — Diagnosis and management of aortic disease
Aortic-dissection instability context.
The scenario’s acknowledged limit: it cannot show bilateral pulse/BP or neurological findings.
AHA / ASA, 2026 — Acute ischaemic stroke guideline
Stroke as a deliberate negative-control scenario: important, but not diagnosable from monitor values.
American Heart Association, 2020 — FAST recognition
The non-monitor recognition boundary documented for the stroke case.
12-lead ECG and rhythm morphology
Educationally recognisable vectors, lead relationships and morphology features.
Validation status
Guideline-grounded · descriptiveWhat this covers
Pre-excitation (WPW)
The WPW pattern is drawn over one representative left lateral pathway, in sinus rhythm and in AF.
- The delta wave starts the QRS early while the rest of the beat stays on time, so the readouts measure a shorter PR and a wider QRS off the trace.
- In AF it is pre-excited AF. Each beat’s share of pathway conduction follows the cycle before it, so the width changes beat to beat, and no cycle is shorter than the pathway’s refractory period (200 ms, a teaching value).
- No QRS is reported in pre-excited AF, since no one width matches the beats.
- NAP makes no pathway-localisation claim.
Ischaemia: ST depression and T inversion
The NSTEMI picture is drawn as two layers that combine: ST depression, which is on or off, and T-wave inversion by territory.
- ST depression has no territory because it does not localise the culprit artery; T-wave inversion does, so it is anterior, inferior or lateral.
- The inversion is narrow and symmetric with a flat ST, the ischaemic shape rather than the lopsided strain of LVH.
- Drawn over a normal QRS only; a bundle-branch block or a delta wave already changes the T.
- The depths are teaching values past the Fourth Universal Definition’s thresholds: ST depression of 0.5 mm, T inversion beyond 1 mm, in two neighbouring leads.
- The Wellens pattern is the anterior inversion; its biphasic form is not modelled.
Posterior and right-sided leads
The extended chest leads are derived from the standard ones: V7–V9 continue V6 and V3R–V6R continue V1, each scaled down by a fixed teaching factor for its distance.
- So every rhythm, block and age band reaches them without numbers of their own; the standard twelve leads are unchanged.
- Each infarct territory states its own ST in every extended lead: posterior ST elevation in V7–V9, RV elevation in V3R–V6R largest in V4R, ST depression without elevation behind.
- The elevations sit past the 0.5 mm threshold the Fourth Universal Definition sets for these leads.
- Interval measurements stay over the standard twelve, and the RV sign does not fade on its own as it does in patients.
Muscle tremor and baseline wander
The instructor can add recording artefact: muscle tremor, slow baseline wander, or both, on every ECG at once.
- It is drawn per electrode, so each lead carries the difference of its electrodes and the limb-lead relationships hold.
- The amplitudes are NAP’s own teaching values, chosen to be plain at a glance; no published figure was found for them.
- The heart rate, alarms and AED read the rhythm, not the trace, so the artefact changes none of them.
Brugada pattern
Brugada type 1 is drawn as a teaching morphology in V1 and V2: a lifted J point and a coved ST running into a negative T.
- Right chest leads only, so the limb leads, the QRS width and the monitor strip are unchanged.
- Drawn over a normal QRS only; the saddleback type 2 and high-lead placement are not modelled.
Setting a target QTc
An instructor can set a target QTcF (QT corrected for heart rate by the Fridericia formula) to teach the long-QT picture.
- The interval readout then measures it back off the drawn trace, rather than repeating the number that was typed in.
- The dial’s 450 / 480 / 500 targets follow the categorical outlier boundaries the ICH E14 guidance suggests for QTc analysis. They are authoring conveniences, not diagnostic categories.
Two corrections, printed together
The readouts print both QTcF (Fridericia) and QTcB (Bazett), each labelled, with QTcF as the primary value the ≥500 marker is evaluated against.
- Bazett, the correction many bedside monitors print by default, visibly over-corrects as the heart rate rises.
- Showing both on the same beat lets that divergence be demonstrated live: at a healthy infant’s default rate the drawn trace reads QTcB above 480 while QTcF stays in the low 420s.
- None of this is a claim of diagnostic or screening validity: the two numbers are measurements of a simulated trace, labelled by method.
Details
- Why Fridericia is used for marking and authoring: NAP’s rendered QT/RR relation is close to a cube-root law, so QTcF stays nearly rate-flat over the drawn trace.
- The ICH E14 Q&As describe Bazett as an inferior correction in adults and Fridericia as likely to be appropriate in most situations.
- A widely used commercial 12-lead analysis program computes Bazett, Fridericia and Framingham, with Bazett the default reported value.
Which lead the intervals come from
The monitor measures the lead it is sweeping; the 12-lead measures across all twelve, from the earliest onset in any lead to the latest offset in any lead.
- Across all twelve is the standard for 12-lead measurement, and each readout says which it is.
- The two can legitimately differ for the same patient: a single lead reads shorter when its own onset or offset happens to sit on the baseline.
- For example, a bundle-branch block that measures about 177 ms on the monitor spans about 190 ms across twelve leads.
- For the same reason the monitor may decline to report a QT it genuinely cannot see, where the 12-lead can.
The ≥500 ms marker
At or above a QTcF of 500 ms the value carries a ≥500 marker, evaluated against the Fridericia value only, never the Bazett secondary.
- The 500 ms line follows the highest of the ICH E14 categorical outlier boundaries (450 / 480 / 500 ms).
- It applies identically across simulated age groups: no guideline body publishes an age-banded QTc threshold above the neonatal period, and NAP does not invent one.
- The marker describes a measurement, neither an age-specific reference range nor a prediction that the rhythm will deteriorate. Selecting torsades remains the instructor’s deliberate act.
Ventricular fibrillation, coarse or fine
VF is drawn wave by wave: each deflection has its own width, height and lean, at about 4 to 6 per second, smoothed as a monitor’s display filter would.
- Coarse VF spans roughly 1 to 3 mV.
- Fine VF is about 0.2 to 0.3 mV (2 to 3 mm), kept above the 100 µV line an AED treats as asystole, and drawn no faster than coarse, since VF slows as it goes on.
- The amplitude classes follow the AED literature and Weaver 1985; the shape is a teaching drawing, not a recording.
- The AED advises from the rhythm the instructor set, so it advises a shock for fine VF exactly as for coarse, and VF never turns from coarse to fine on its own.
The unauthored baseline
The unauthored baseline is a simulation output built from each age band’s resting QT rather than a fixed corrected target.
- So the displayed QTcB varies with heart rate, rising as the rate rises, while the displayed QTcF stays nearly flat.
- Both baseline values are simulation outputs, not clinical normal ranges.
Grounded in 35 sources
Kligfield et al. for AHA/ACCF/HRS, 2007 — ECG standardization, Part I
Standard lead nomenclature, acquisition concepts, the waveform-generation-vs-interpretation distinction, and global measurement across simultaneously recorded leads as the basis for 12-lead interval durations.
ICH E14, 2005 (+ E14/S7B Q&As R1, 2026) — Clinical evaluation of QT/QTc prolongation
The categorical outlier boundaries (QTc >450 / >480 / >500 ms, §3.2.2) behind the QT dial’s targets and the ≥500 marker, and the Q&A (Q1.5) assessment that Bazett is an inferior correction in adults, Fridericia likely appropriate in most situations.
Grounding for which correction NAP marks against, not a claim that NAP performs E14 analyses.
Widely used commercial 12-lead analysis program — physician’s guide
Real-device convention for printing a method-labelled QTc: the program computes Bazett, Fridericia and Framingham corrections, with Bazett the default reported value unless denoted. The precedent for NAP printing both corrections labelled by method.
Weaver et al., 1985 — Amplitude of ventricular fibrillation waveform and outcome after cardiac arrest
VF peak-to-peak amplitude averaged 0.55 ± 0.25 mV, and “fine” VF of 0.2 mV or less was present in 17% of patients: the basis for the fine grade sitting at about 2 to 3 mm.
Strohmenger, Lindner & Brown, 1997 — Analysis of the VF ECG signal amplitude and frequency before shock
Dominant VF frequency of about 4.6 Hz before successful shocks and lower before unsuccessful ones: the basis for the 4 to 6 per second wave rate and for fine VF being no faster than coarse.
Surawicz et al. for AHA/ACCF/HRS, 2009 — Part III: intraventricular conduction
Bundle-branch-block morphology and conduction terminology.
Rautaharju et al. for AHA/ACCF/HRS, 2009 — Part IV: ST, T, U, QT
ST/T morphology conventions for ischaemia, pericarditis and electrolyte overlays.
Wagner et al. for AHA/ACCF/HRS, 2009 — Part VI: acute ischaemia / infarction
Contiguous-lead and reciprocal-change relationships for the STEMI teaching overlays.
Mills et al., 2026 — Fifth Universal Definition of Myocardial Infarction
Localisation / contiguous-lead context, and the warning that NAP’s ST amplitude is a teaching default, not a universal diagnostic threshold.
ACC / AHA, 2025 — Management of acute coronary syndromes
ACS / STEMI scenario scope and contemporary clinical context.
Pava et al., 2010 — R-wave peak time at DII
The delayed lead-II R-wave peak that makes simulated VT recognisable on a single-lead monitor.
Vereckei et al., 2008 — aVR wide-QRS tachycardia algorithm
Initial-versus-terminal activation features used in NAP’s wide-complex morphology.
Brugada et al., 1991 — Regular wide-QRS tachycardia
The prolonged RS-interval feature represented in the VT teaching morphology.
Sokolow and Lyon, 1949 — Ventricular complex in LVH
The voltage-pattern teaching overlay for LVH.
No diagnostic sensitivity/specificity is asserted.
Miner, Grigg and Hart, 2023 — Wellens syndrome
The characteristic precordial T-wave teaching pattern, drawn as anterior T inversion, and its clinical-context caveat.
Fuchs et al., 1982 — ECG localisation of coronary narrowings in one-vessel disease
T-wave inversion pointed to the narrowed artery in 84% of patients and ST depression in 60%, “not useful”: why T inversion takes a territory and ST depression does not.
Mark et al., 1987 — Localising coronary obstructions with the exercise treadmill test
Exercise ST depression appears most often in V5–V6 whichever artery is involved.
Hayden et al., 2002 — T-wave inversion: differential diagnosis in the chest pain patient
Ischaemic T inversion is narrow and symmetric with an isoelectric ST; LVH and other non-ischaemic causes are widely splayed.
Savonitto et al., 1999 — Prognostic value of the admission ECG in acute coronary syndromes (GUSTO-IIb)
At presentation 22% of patients had T-wave inversion and 35% ST depression: the two layers the Ischaemia section offers.
de Zwaan, Bär and Wellens, 1982 — ECG pattern of a critical proximal LAD stenosis
The precordial T-wave pattern behind the Wellens one-tap.
Rhinehardt et al., 2002 — ECG manifestations of Wellens’ syndrome
The deep symmetric form NAP draws, and the biphasic form it does not.
Hassen et al., 2014 — Lead aVL in the early diagnosis of myocardial infarction
aVL as the lead facing away from the inferior wall, where inferior T inversion draws a taller T.
Shah et al., 1997 — ST depression of circumflex occlusion versus non-occlusive ischaemia
Peak ST depression in V2–V3 marks circumflex occlusion: the posterior pattern, kept apart from non-localising depression.
Yamaji et al., 2001 — ST elevation in aVR in acute left main obstruction
The aVR elevation that the diffuse ST-depression pattern carries.
Thygesen et al., 2018 — Fourth Universal Definition of Myocardial Infarction
The ST-depression (0.5 mm) and T-inversion (beyond 1 mm) thresholds the ischaemia depths are set well past, and the 0.5 mm elevation threshold for V7–V9 and V3R/V4R.
Wung & Drew, 2001 — Posterior-lead criteria in circumflex occlusion
Why the posterior-lead threshold is 0.5 mm, and posterior ST elevation without anterior depression.
Matetzky et al., 1999 — Isolated ST elevation in V7–V9
Posterior infarction seen only in V7–V9, from the circumflex artery.
Poh et al., 2004 — No V7–V9 elevation in non-occlusive ischaemia
ST depression drawn without posterior elevation.
Braat et al., 1983 — Right precordial leads in inferior infarction
ST elevation in V4R as the sign of RV involvement, and how quickly it fades.
Lopez-Sendon et al., 1985 — Right precordial leads in RV infarction
ST elevation in V4R greater than in V1–V3 as the specific RV sign.
Zehender et al., 1993 — RV infarction and prognosis
Why recording V4R matters in an inferior infarction.
Katoh et al., 2011 — Synthesised posterior and right-sided leads
A real-monitor precedent for extended leads derived from the standard twelve (NAP’s own rule is simpler).
KDIGO Controversies Conference, 2020 — Potassium management in kidney disease
The association between hyperkalaemia severity and ECG change.
One overlay is not treated as the full progression.
Lindner et al. for KDIGO, 2020 — Acute hyperkalaemia in the emergency department
Emergency-recognition context.
The documented gap between NAP’s peaked-T overlay and a full graded QRS/sine-wave sequence.
European Society of Cardiology, 2025 — Myocarditis and pericarditis
Diffuse ST/T and pericardial-disease teaching context, including tamponade cross-reference.
Defibrillation, cardioversion, pacing and NIBP
Device actions are simplified for instruction.
Validation status
Guideline-grounded · descriptiveWhat this covers
What the guidelines do and do not establish
Guideline pathways inform state transitions and recognisable indications.
- They do not make NAP a treatment recommender, or establish real-device timing, energy, capture or blood-pressure accuracy.
Mean arterial pressure
The mean arterial pressure appears beside the non-invasive systolic/diastolic just as a real monitor shows it, computed with the standard bedside formula (MAP = diastolic + one-third of the pulse pressure).
- The cuff readings themselves are instructor-controlled, not a validated oscillometric measurement.
Synchronised cardioversion
A synchronised cardioversion is recognised as its own action rather than a defibrillation, and is judged against its own lower adequacy threshold.
Adenosine
Adenosine is an ask-instructor prompt, not a modelled drug: the instructor is the physiology, so the instructor chooses and records the outcome, and the simulator never evolves the patient on its own.
- Two outcomes: a conversion, or a transient block that unmasks an underlying atrial rhythm without stopping it.
- The outcomes follow the rhythm the dose was given in. SVT, a re-entry through the AV node, can only convert or continue.
- The unmasking block is offered only on the atrial rhythm it reveals, and returns to it.
- In AF, from adolescence up, it is a brief 3:1 block: a few slow, irregular beats over the fibrillating baseline, then the same AF at the same rate.
- It does not treat AF. The block shows the rhythm was never SVT.
- In pre-excited AF the block sends more conduction down the pathway: the instructor chooses faster and wider for a while, or degeneration to VF, the harm case the guidelines warn about. The slowing reveal is not offered there.
- Focal atrial tachycardia is in the rhythm picker. At one-to-one conduction it can pass for sinus tachycardia or SVT, and the adenosine block is what tells them apart. NAP draws its P wave with the sinus axis, a simplification.
- Where it is offered. The Therapy tab offers it on any rhythm, at the instructor’s discretion. The floating shortcut appears on a regular narrow-complex tachycardia: SVT, focal atrial tachycardia, and atrial flutter only while it conducts 2:1 or faster.
- Why slower flutter and AF are left out of the shortcut. At 3:1 or slower the rate is too slow for anyone to reach for adenosine; AF, being irregular, is left out entirely.
A pulse with VT and torsades
Ventricular tachycardia can run with or without a pulse, so NAP leaves that to the instructor: one tap on the pulse button changes it.
- The starting point follows how each presents. Most sustained VT reaches an emergency department with a pulse and a stable circulation, so VT keeps its pulse when picked.
- The floating pulse button turns amber to show the decision is the instructor’s.
- Torsades in NAP runs until the instructor changes it. Sustained torsades is the form that collapses the circulation or degenerates into VF, so it starts without a pulse when picked.
- Torsades with a pulse (usually brief, self-terminating runs, and the classic magnesium scenario) stays one tap away.
AED mode
AED mode is a representative AED training model, not a copy of any device.
- The learner attaches pads, presses analyse, and, when advised, delivers a fixed shock through a two-minute CPR cycle with spoken prompts.
It does not analyse the ECG
NAP does not analyse an ECG signal: the advice is derived from the rhythm the instructor has set, modelling what a representative AED would decide, so it cannot mis-detect.
- It advises a shock for ventricular fibrillation and rapid ventricular tachycardia and withholds one otherwise.
- The rate above which it treats monomorphic VT as shockable is a representative teaching threshold, not a validated cutoff: commercial devices genuinely disagree at that boundary.
Age-banded energy
AED mode is available for every patient class, with energy age-banded as a real AED does it (200 J standard, an attenuated 75 J below the standard-pads age).
- A representative training model matched to no specific device, carrying no validated-algorithm, paediatric-AED or PALS claim.
Instructor-set CPR EtCO₂
CPR EtCO₂ follows Good/Poor compression quality by default; the instructor can set an arrest value on the Patient tab instead.
- Other CPR signals use the inverse of the same quality-to-EtCO₂ mapping, clamped to its effectiveness range.
- This is an instructor-authored teaching value. It acts only while compressions run on a patient with no pulse; otherwise EtCO₂ reads exactly as it does by default.
AED prompts during CPR
The AED can also interact with CPR and coach compression quality, but it only reflects what the instructor has set, never anything it measures.
- When the instructor is running compressions the AED waits and says “stop compressions” before analysing.
- It voices “push harder” or “good compressions” according to the Good/Poor quality the instructor authored, or the effectiveness derived from instructor-set CPR EtCO₂.
- A metronome runs at the authored compression rate whenever compressions are running.
- This is not real-time CPR feedback, and nothing is sensed.
Two boundaries
Both are representative teaching behaviours, adjustable per room (auto-analyse and coaching are instructor options), and neither names a manufacturer.
- Refusing to analyse during compressions models a conventional AED; modern devices analyse through compressions.
- The quality coaching models a CPR-feedback-capable device rather than every AED.
Grounded in 22 sources
Kerber et al. for the American Heart Association Task Force on Automatic External Defibrillation, 1997 — AED arrhythmia-analysis algorithm performance
That the AHA sets high sensitivity for shockable and high specificity for non-shockable rhythms as the AED targets.
It grounds NAP’s AED as a representative model, not a validated detection algorithm.
Nishiyama et al., 2015 — Diagnostic accuracy of commercially available automated external defibrillators
That commercial AEDs disagree markedly at the VT boundary (shock-advice for VT above 180/min ranged 36–96% across four devices).
The basis for NAP presenting its rate gate as representative, not a validated cutoff matching any one device.
de Graaf et al., 2021 — Analyzing the heart rhythm during chest compressions (cprINSIGHT AED algorithm)
That modern AEDs can analyse the rhythm through ongoing compressions.
So NAP states that its “wait, stop compressions to analyse” behaviour models a conventional AED: a teaching choice rather than a universal truth.
Christenson et al., 2009 — Chest compression fraction determines survival in out-of-hospital VF; Cheskes et al., 2011 — Perishock pause and survival
That minimising hands-off time (higher compression fraction, shorter peri-shock pause) is tied to survival: the teaching point behind modelling the AED’s hands-off cadence at all.
American Heart Association, 2025 — Electrical cardioversion algorithm
Synchronised-versus-unsynchronised teaching behaviour and the unstable-tachyarrhythmia transition model.
American Heart Association, 2025 — Adult tachyarrhythmia with a pulse
Instability / cardioversion logic for SVT, AF with rapid ventricular response and VT with a pulse, and synchronised cardioversion at the device’s recommended energy (the maximum if that is not known).
The separate, lower cardioversion floor NAP uses rests on the ERC energies below.
Soar et al. for the European Resuscitation Council, 2021 — Adult advanced life support guideline
European synchronised-cardioversion energies, cross-checked against the American ranges so the threshold is not drawn from a single guideline tradition.
Glover et al., 2008 — Biphasic energy selection for transthoracic cardioversion of atrial fibrillation (BEST AF)
That first-shock success is materially higher at higher biphasic energies.
So NAP states openly that a single low adequacy floor is charitable to atrial fibrillation, rather than pretending one threshold fits every rhythm.
Lasa et al. for the American Heart Association and American Academy of Pediatrics, 2025 — Part 8: Paediatric advanced life support
Adenosine as first-line for stable regular narrow-complex SVT in children, so the prompt spans paediatric rooms too, its outcomes and their rates age-scaled to the class (flutter-reveal only in the older bands, never the infant).
A descriptive, instructor-authored teaching depiction, not a PALS or validated-paediatric claim.
Page et al. for the ACC/AHA/HRS, 2015 — Guideline for the management of adult patients with supraventricular tachycardia
The differential the authored outcomes depict: adenosine either terminates an AV-node-dependent re-entry, or by transient block transiently slows a non-nodal atrial mechanism, unmasking it without terminating it.
Rankin et al., 1989 — Value and limitations of adenosine in the diagnosis and treatment of narrow and broad complex tachycardias
Where it failed to convert, it revealed atrial or sinus tachycardia, correctly diagnosing every narrow-complex case: the drug, not the trace, tells atrial tachycardia from SVT. Its pauses (over 2 s in 16%, longest 6.1 s) bound NAP’s reveal holds.
DiMarco et al., 1983 — Adenosine: electrophysiologic effects and therapeutic use for terminating paroxysmal supraventricular tachycardia
That the transient block preserves atrial activity rather than producing a flat line: why NAP draws the reveal as an ongoing atrial rhythm at a slowed ventricular response, and why the effect is brief.
diMarco et al., 1985 — Diagnostic and therapeutic use of adenosine in patients with supraventricular tachyarrhythmias
That adenosine’s block leaves atrial fibrillation untouched while the ventricle slows: why the AF result is a few slow beats over the same fibrillating baseline, then the same AF.
El Assaad et al. for PACES, 2021 — Management and outcomes of atrial fibrillation in 241 healthy children and young adults
That AF in otherwise healthy children is rare and begins around adolescence: why the AF result is offered for the adolescent and adult, not the younger bands.
Domanovits et al., 1999 — Sustained ventricular tachycardia in the emergency department
That most sustained VT arrives with a pulse: of 75 emergency-department patients, 58 (77%) were haemodynamically stable. Why VT keeps its pulse when picked.
Havakuk et al., 2020 — Clinical presentation of sustained monomorphic ventricular tachycardia without cardiac arrest
That sustained monomorphic VT at a mean rate of 165/min commonly presents conscious, with chest pain, breathlessness or dizziness.
Cohagan & Brandis, StatPearls, 2023 — Torsade de pointes
Most torsades episodes are self-limiting and around half of patients asymptomatic, yet a run can degenerate into VF; pulseless torsades is defibrillated, unstable torsades with a pulse cardioverted. So torsades with a pulse stays available, and sustained torsades starts pulseless.
Wigginton et al. for the American Heart Association, 2025 — Part 9: Adult advanced life support
The split the pulse button teaches: pulseless VT follows the cardiac-arrest algorithm; VT with a pulse is a tachycardia managed with synchronised cardioversion. Also adenosine’s place in regular narrow-complex tachycardia, and the caveat against it in irregular wide-complex tachycardia.
American Heart Association, 2025 — Adult bradycardia with a pulse
The compromised-bradycardia and transcutaneous-pacing teaching path.
American Heart Association, 2025 — Adult post-cardiac arrest care
Post-ROSC care is a set of target ranges (MAP ≥ 65 mm Hg, PaCO₂ 35–45 mm Hg, SpO₂ 90–98 %), not one universal post-ROSC vital set.
ACC / AHA / ACCP / HRS, 2023 — Diagnosis and management of atrial fibrillation
Irregular AF rhythm behaviour and urgent-cardioversion context when instability is represented.
Muntner et al. for the American Heart Association, 2019 — Measurement of blood pressure in humans
Cuff-selection, positioning and oscillometric conventions that frame NIBP simulation and paediatric cuff checks.
It does not validate NAP’s generated readings.
Alarms
NAP’s alarm behaviour is a teaching abstraction whose priorities follow the priority framework of IEC 60601-1-8: potential harm crossed with onset, so a condition that can kill within seconds ranks high regardless of any numeric.
Validation status
Guideline-grounded · descriptiveWhat this covers
Crisis alarms
Crisis alarms therefore behave as a real patient monitor ranks them.
- Life-threatening rhythms (ventricular tachycardia, ventricular fibrillation and asystole) and apnoea raise a high-priority alarm by recognising the condition, not only when a number crosses a limit.
- A lethal alarm can’t be switched off with a per-vital toggle.
Apnoea waits
When a patient stops breathing but is still circulating, the apnoea alarm waits a short onset window (20 s) before it annunciates.
- A monitor does not call apnoea on a single missed breath.
- The respiratory-rate number still drops to zero immediately, and an arrest, which has no breathing to wait for, alarms at once.
Other alarms annunciate at once
Apart from apnoea, an alarm sounds the moment a value crosses its limit.
- A real monitor usually waits a beat first, to avoid firing on a noisy sample or a momentary blip.
- NAP has no such transients to filter: the instructor is the physiology, so a value only changes because someone changed it, and the monitor never moves a number on its own.
- The delay is left out deliberately: a pause between your action and the alarm would read as the simulator being slow rather than as anything about alarms.
Simultaneous alarms take turns
When more than one alarm of the same priority is active, the banner cycles through them rather than showing only the first.
- So a desaturation cannot sit hidden behind a heart-rate alarm on a screen being watched from across the room.
The alarm sound is NAP’s own
The alarm tones are a house sound, modelled on the pitches a real monitor documents for its standard-conformant setting, in NAP’s own shorter cadence.
- Real devices occupy the same position: the major bedside monitors ship their own alarm sounds by default and offer the standard set as an option.
- So NAP does not claim to reproduce any particular device’s alarm, or the standard’s full burst.
Detection performance
NAP is not an IEC-conformant device and does not replicate real arrhythmia-detection performance.
Grounded in 4 sources
International Electrotechnical Commission, 2020 — IEC 60601-1-8:2006+A1:2012+A2:2020
The distinction among alarm-condition priorities and general alarm-signal conventions.
Patient-monitor manufacturer — instructions for use and configuration guide
The red / yellow / technical three-channel split, the red arrhythmia list, apnoea as a high-priority alarm after a configurable onset delay (default 20 s), and the guard that keeps lethal alarms from being switched off.
Vendor interface concepts, not device equivalence or NAP’s exact numbers.
Patient-monitor manufacturer — arrhythmia-algorithm clinical resource
That a “lethal” arrhythmia class (asystole, VF/VT) is a conventional non-optional floor: the concept behind lethal codes bypassing the per-vital off toggle.
Interface concept, not algorithm equivalence.
Cosentino et al., 2024 — Performance comparison of 6 in-hospital patient monitoring systems in the detection and alarm of ventricular cardiac arrhythmias
That treating asystole/VF/VT as the high-severity class is universal across vendors rather than a single-vendor quirk.
Establishes convention, not NAP validation.
Respiration & respiratory rate
How NAP decides a respiratory rate is measurable and which source it trusts.
Validation status
Guideline-grounded · descriptiveWhat this covers
Setting a pattern sets a rate
Choosing a breathing pattern also sets a starting rate for it, which the instructor can still adjust.
- A gentle note appears if the rate chosen reads oddly for that pattern.
- The rate set is the rate the monitor shows, with no hidden multiplier.
The patterns it renders
Normal, Cheyne–Stokes, Kussmaul, Biot/ataxic, agonal and apnoea are recognisable rate-and-depth teaching cues whose defining cadence is grounded in standard clinical descriptions.
- NAP does not reproduce any individual patient’s respiratory mechanics.
- Each pattern carries a physiologically-plausible starting rate: an adjustable clinical-judgment teaching value grounded in the pattern definitions, not a measured or validated reference standard.
Where the rate comes from
On a real monitor RR is derived from impedance pneumography (ECG electrodes), the pleth (SpO₂ probe), or capnography.
- NAP names the best available source (capnography > pleth > impedance) and blanks the rate when none is attached.
- With No trace and the capno line on, RR is counted from CO₂, so it falls to zero and the apnoea alarm follows its onset wait; with the line off, the pleth or ECG estimate keeps counting the breathing effort.
The rate is counted over a window
Like a monitor counting breaths, NAP reports the respiratory rate averaged over a short rolling window rather than instant by instant.
- An irregular pattern (agonal gasping, or the pause in Cheyne–Stokes) reads as a low rate between breaths rather than dropping to zero, while apnoea still reads a true zero.
- At very slow gasping rates a breath can fall outside the window altogether, and the rate then reads zero until the next one: the monitor reports what it counted, as a real one would.
- Steady patterns are not averaged, so an ordinary rate change still shows immediately.
- The window length is a teaching convention chosen for clarity, not a figure taken from a published standard or copied from a particular device.
What the sources establish
The sources below inform this source model, the pattern definitions and the reliability ordering, not a validation of NAP’s rate values, which remain instructor-set.
Grounded in 5 sources
Porter and Graham for StatPearls, 2025 — Abnormal Respirations
The eupnoeic 12–20/min baseline and the defining features of the abnormal patterns (Kussmaul as deep and fast, Biot/ataxic as clusters separated by irregular apnoeas, agonal as slow gasping), informing each pattern’s recognisable cadence.
Not a per-patient mechanics claim.
Chapa-Rodriguez, Para, Sankari and Bollu for StatPearls, 2026 — Cheyne–Stokes Respirations
The smooth crescendo–decrescendo of tidal volume separated by central apnoeas and the characteristically long cycle: grounding the waxing/waning Cheyne–Stokes cue and the decision that its apnoeic trough must not false-fire the apnoea alarm.
Charlton et al., 2018 — Breathing-rate estimation from the ECG and photoplethysmogram (IEEE Rev Biomed Eng)
Pleth-derived (photoplethysmographic) respiratory rate as an established, reviewed measurement class, not a niche add-on.
Eisenkraft et al., 2023 — Clinical validation of a wearable respiratory-rate device (Chron Respir Dis)
Modern agreement of pleth-derived RR against capnograph and ventilator references.
van Loon et al., 2018 — Accuracy of remote continuous respiratory-rate monitoring (Can J Anaesth)
Capnography as the reference method and impedance pneumography as the widest limits of agreement: the capnography-over-impedance end of the source-reliability ordering.
It did not test a pleth-derived rate.
Advanced haemodynamics
Reference bands, derived relationships, directional preset fingerprints, waveform conventions and respiratory interaction.
Validation status
Beta · external face-validation openWhat this covers
A number only when the line is in
A number appears only when the line that measures it is actually in place.
- Central venous pressure needs a central line.
- Pulmonary pressures, thermodilution cardiac output and mixed-venous saturation need a pulmonary-artery catheter.
- The wedge shows only while the balloon is inflated, because it is a brief manoeuvre rather than a standing reading.
- A saturation taken from a central line is labelled as such and never presented as a mixed-venous one.
Cardiac output, by method
Cardiac output can also be estimated from the arterial line alone: an uncalibrated pulse-wave-analysis estimate, labelled as such and kept distinct from the pulmonary-artery-catheter thermodilution figure.
- It is presented as a trend rather than a calibrated measurement.
- One method label at a time: NAP shows one patient’s cardiac output under one method label at a time, rather than inventing a difference between the two methods.
Coronary perfusion pressure during CPR
The coronary-perfusion-pressure readout during CPR is a pressure difference between two sites, so it appears only when an arterial line and a central line are both in place.
- It leaves the screen when compressions stop.
- It marks the level historically associated with return of circulation as a teaching landmark, without asserting anything about a particular patient’s outcome.
A derived number is withheld rather than invented
Every derived index is computed from the values on screen at the moment it is read, and is shown only while the quantities it depends on make it meaningful.
- A resistance is withheld when there is no forward pressure gradient, rather than displayed as a negative number no monitor could produce.
- No forward gradient means a central venous pressure at or above the mean arterial pressure, or a wedge pressure at or above the mean pulmonary artery pressure.
- The same rule blanks the flow-derived indices when there is no perfusing rhythm.
- NAP would rather show nothing than something a real device could never show.
Details
- Why a resistance needs a gradient: it is a pressure difference divided by a flow.
Waveform timing comes from the same cardiac clock
The venous trace is drawn from the same beat timeline the ECG is drawn from, rather than from a second rhythm of its own.
- In dissociated rhythms the a-wave is keyed to the independent atrial timeline that places the P waves on the ECG, so an atrial contraction within ventricular systole shows as an accentuated a-wave on that beat.
- That is the recognisable cannon a-wave teaching pattern, aligned with the rhythm above it.
- The pronounced narrowing seen under the tamponade picture (where it falls on inspiration) and under positive-pressure ventilation (where the swing reverses with the breath) is applied to each affected channel’s own pulse pressure.
- The ordinary respiratory variation is a bounded shift of the whole trace, and is not re-modelled as a narrowing.
- The timing and the proportions are structural; the rendered magnitudes are teaching values, with no claim to validated waveform fidelity.
Details
- How the narrowing is applied: as a share of each affected channel’s own pulse pressure, rather than as a fixed number of millimetres.
What this establishes
These establish starting concepts, not clinical validation of NAP’s numbers or waveforms. This module remains governed by an open external face-validation checklist.
Grounded in 24 sources
Marino, 2014 — Marino’s The ICU Book (4th ed.)
General adult haemodynamic reference bands used as soft fingerprints rather than clamps.
Haemodynamic-monitoring manufacturer — normal adult parameters pocket card
Starting adult ranges for invasive pressures, flow, resistance and mixed-venous saturation.
Vanderbilt University Medical Center CVICU, 2020 — Hemodynamic parameters
Calculation definitions and normal-value cross-checks for derived haemodynamic channels.
Haemodynamic-monitoring manufacturer — normal parameters reference
An additional cross-check for the normal adult haemodynamic reference set.
van Diepen et al., 2024 — Mixed cardiogenic shock: a standardized classification and hemodynamic definition
The mixed-shock directional fingerprint linking flow, filling pressure and vascular resistance.
Kapur et al., 2022 — Stages of cardiogenic shock severity
Cardiogenic-shock stage variables that constrain the scenario fingerprint rather than dictate one presentation.
SCAI — Mechanical circulatory support in cardiogenic shock: QI tips
The haemodynamic-variable selection used in the cardiogenic-shock teaching case.
Paradis et al., 1990 — Coronary perfusion pressure and return of spontaneous circulation
The coronary-perfusion-pressure landmark marked on NAP’s CPR readout.
A small 1990 cohort under very different resuscitation practice, used as a legible teaching landmark rather than a validated cut-off.
Gaubert et al., 2020 — Haemodynamic profiles of cardiogenic shock depending on their aetiology
Aetiology-dependent haemodynamic profiles in cardiogenic shock: how flow, filling pressure and resistance differ by cause.
Gopal, Sokup Ivanov and Meer, 2026 — Cardiac tamponade
Diastolic pressure equalisation and tamponade waveform / preset direction.
Van Dam, Hashmi and Fitzgerald, 2024 — Pulsus paradoxus
The clinical definition and respiratory-interaction context for NAP’s pulsus-paradoxus model.
Curtiss et al., 1988 — Pulsus paradoxus and cardiac tamponade severity
The magnitude / direction of respiration-linked systolic pressure variation in tamponade.
Klopfenstein et al., 1985 — Pulsus paradoxus and right ventricular diastolic collapse in the early detection of cardiac tamponade
An experimental comparison of pulsus paradoxus with an echocardiographic sign for detecting tamponade.
The respiration-linked arterial fall as a detection sign, not a mechanistic model.
Piazza and Goldhaber, 2006 — Acute pulmonary embolism, Part I
The PA-pressure, wedge-pressure and pulmonary-resistance direction of the massive-PE preset.
European Society of Cardiology, 2019 — Acute pulmonary embolism
The high-risk-PE / shock context and risk-marker selection used in scenario review.
AHA / ACC, 2026 — Evaluation and management of acute pulmonary embolism
The current clinical framing of high-risk PE.
Bootsma et al., 2022 — The contemporary pulmonary artery catheter, Part 1
Invasive-pressure waveform anatomy, zeroing / levelling concepts, and fast-flush and wedge teaching behaviours.
Quaal, 2001 — Accuracy of pulmonary artery catheter measurements
Caution around waveform acquisition and interpretation.
It does not validate NAP’s invasive-pressure rendering.
Bootsma et al., 2021 — The contemporary pulmonary artery catheter, Part 2
The measurement set a pulmonary-artery catheter actually provides (pulmonary-artery pressure, occlusion or wedge pressure, thermodilution cardiac output and mixed-venous saturation): the numbers that would be false notes without one.
Monnet and Teboul, 2015 — Minimally invasive monitoring
The decline of routine pulmonary-artery-catheter use in favour of less-invasive cardiac-output methods: why thermodilution cardiac output is treated as catheter-gated, and why an arterial-line cardiac-output estimate is worth teaching.
Saugel et al., 2021 — Cardiac output estimation using pulse wave analysis
The starting concept behind the arterial-line cardiac-output readout: an uncalibrated pulse-wave-analysis estimate inferred from the arterial pressure waveform, labelled as an estimate and kept distinct from thermodilution.
A trend, not a calibrated measurement. It grounds the teaching frame, not any accuracy claim about NAP’s number.
Lequeux et al., 2010 — Continuous mixed venous and central venous oxygen saturation in cardiac surgery
That a central-venous saturation reads on average higher than the true mixed-venous value: the offset behind labelling the central-line-only reading separately.
Varpula et al., 2006 — Mixed venous oxygen saturation cannot be estimated by central venous oxygen saturation in septic shock
A cross-check of that offset’s magnitude and of the non-interchangeability of the two saturations.
Lorentzen et al., 2008 — Central venous oxygen saturation cannot replace mixed venous saturation in cardiac surgery
That the relationship between the two, while offset on average, is too variable to be interchangeable, so the central-line value is never relabelled as mixed-venous.
Processed EEG / depth of anaesthesia
NAP presents a generic 0–100 processed-EEG index plus simulated EEG-derived features, including a density spectral array (DSA): a frequency-over-time colour strip of the same spectral estimate the edge frequency is read from.
Validation status
Beta · external face-validation openWhat this covers
Validation status
This module’s transitions remain subject to a separate external face-validation gate.
The density spectral array
The DSA is a generic depth-and-suppression view: it shows how the spectrum shifts with anaesthetic depth and how burst suppression appears.
Grounded in 12 sources
Depth-of-anaesthesia monitor manufacturer — product information
The display vocabulary (processed index, signal quality, EMG and suppression ratio) used to define the module’s visible channels.
Depth-of-anaesthesia monitor manufacturer — operator-documentation index
The official route to operator documentation.
Used only for interface concepts, not algorithm equivalence.
Nimmo et al., 2019 — Safe practice of total intravenous anaesthesia
Clinical context for processed-EEG monitoring during TIVA, and the decision not to portray one index as a complete anaesthetic state.
Gao et al., 2018 — Processed EEG and anaesthetic awareness: meta-analysis
The cautious treatment of outcome claims and the separation of a teaching display from clinical efficacy.
Zhang et al., 2011 — Index-guided TIVA and awareness: a multicentre randomised trial
The awareness-monitoring context.
It is not used as validation of NAP’s index.
Evered et al., 2021 — Anaesthetic depth and delirium: BALANCED substudy
The deliberately cautious relationship between processed-EEG targets and postoperative outcomes.
Purdon et al., 2015 — Clinical EEG for anesthesiologists, Part I
Recognisable awake, propofol, general-anaesthesia and burst-suppression EEG morphology.
Akeju et al., 2014 — EEG signatures of propofol and sevoflurane
The generic spectral picture of anaesthetic depth (slow waves with frontal alpha) used in the teaching presets.
Not its agent-specific signatures: NAP models no anaesthetic agent.
Lee, Egan and Johnson, 2021 — Raw and processed EEG in modern anaesthesia practice: a brief primer
An introduction to the relationship, and possible disagreement, between raw EEG, derived values, artefact and clinical state.
Schuller et al., 2015 — Index decline after neuromuscular blockade in awake volunteers
The EMG / neuromuscular-blockade confound represented in the simulator.
Purdon et al., 2015 — Age-related changes in EEG during propofol anaesthesia
Age as a modifier.
One morphology / index relation is not treated as universal.
Shanker et al., 2021 — Burst suppression: causes and mechanisms
The qualitative burst-suppression state and suppression-ratio teaching channel.
Paediatrics
An Adult↔Paediatric patient class with four age bands (Infant, Small child, Bigger child, Adolescent).
Validation status
Clinician face-checked · broader validation pendingWhat this covers
Validation standing
A paediatric clinician face-checked the numbers as plausible teaching values: not a validated paediatric-fidelity claim, and not a PALS/APLS/ERC-compliance claim.
What the sources informed
These sources informed the age bands, growth-derived body size, vital ranges, alarm defaults, weight-based defibrillation, BP-cuff measurement, fluid references and haemodynamic BSA/CI scaling.
- Each paediatric number is a teaching value grounded in them by clinical judgment, not a reference standard.
Age-adjusted ECG morphology
The ECG waveform is age-adjusted: NAP’s one-vector, one-beat ECG model is parameterised by band, so the limb-lead axis, the precordial R/S progression and the juvenile T-wave pattern move with age.
- The infant’s right-sided emphasis gives way to a progressive leftward shift.
- The chest-lead R/S matures toward the adult direction.
- The juvenile T-wave inversion resolves left-to-right (V3, then V2, then V1) across the bands.
- Each band draws one representative deterministic trace inside the published normal-limits envelopes below. Those envelopes describe a population, not one universal child.
- So this is a plausible teaching ECG for the age, not a validated, diagnostic or PALS ECG.
Out of scope
Neonatal morphology (birth–28 days) is deliberately out of scope: NAP’s youngest band is an infant at six months.
Still outstanding
A stronger clinically-reviewed claim still awaits an external paediatric-ECG specialist’s review of the rendered age-band plates.
Grounded in 15 sources
Royal Children’s Hospital Melbourne — Acceptable ranges for physiological variables
The shipped V1 age-banded reference vital ranges and the need for age-specific alarms.
Royal Children’s Hospital Melbourne — Basic paediatric ECG interpretation
An accessible age/rate cross-check for HR, axis, PR/QRS duration, voltages, R/S ratios and juvenile T waves, grounding the age-adjusted ECG morphology across the four bands.
Rijnbeek et al., 2001 — New normal limits for the paediatric ECG
Age- and sex-specific digital normal limits for intervals, axes and voltages: the calibration envelopes for the age-banded ECG.
Not validation of NAP’s selected targets.
Saarel et al. / Pediatric Heart Network, 2018 — Electrocardiograms in healthy North American children in the digital age
Contemporary age/sex percentile envelopes for HR, P/PR/QRS/QTc, axes and precordial amplitudes, and the caution that sex, race and acquisition method affect normal measurements.
Dickinson, 2005 — The normal ECG in childhood and adolescence
The developmental pattern the age-adjusted ECG evokes: ventricular dominance, R/S progression, the PR–rate relation and the juvenile T-wave sequence.
World Health Organization — Weight-for-age child growth standards
An age-to-weight reference considered for body-size and weight-based simulation.
NAP’s weights follow RCH Melbourne, not this standard.
World Health Organization — Length/height-for-age child growth standards
The age-to-height reference inputs used with weight for body-surface-area calculation.
World Health Organization — Growth reference data for 5–19 years
Extended the growth-derived body-size basis into school-age and adolescent bands.
Mosteller, 1987 — Simplified calculation of body-surface area
The height-and-weight BSA derivation used for indexed haemodynamic quantities.
Resuscitation Council UK, 2025 — Paediatric life support
V1 age-related physiology, paediatric arrest pathways, weight-based defibrillation and circulation teaching behaviour.
American Heart Association, 2025 — Paediatric cardiac-arrest algorithm
Cross-checked the shipped weight-based defibrillation and arrest-state transitions.
Lewis et al., 2016 — Acute management of refractory and unstable paediatric supraventricular tachycardia (J Pediatr)
In acute paediatric SVT adenosine and first-line medical management end most episodes, cardioversion being reserved for unstable or adenosine-refractory SVT: why SVT cardioversion is an instructor-decided post-shock outcome, and infants (lower first-dose response) the harder case.
Flynn et al. for the AAP, 2017 — High blood pressure in children and adolescents
Paediatric cuff / measurement considerations and the warning that age-only BP limits are incomplete.
NICE, 2015 (updated) — Intravenous fluid therapy in children (NG29)
A weight-based fluid reference and its age / weight constraints, considered for paediatric simulation.
Sproul and Simpson, 1964 — Stroke volume in normal children
Historical primary data for the direction of paediatric stroke-volume and cardiac-output scaling.
Modern external review remains required.
Blood gases
An instructor-authored sample whose acid–base quantities are derived from published equations rather than typed in.
Validation status
Beta · external face-validation openWhat this covers
What is authored, and what NAP works out
A gas starts from one of a catalogue of clinical pictures, which carries the whole measured set: tensions, bicarbonate, electrolytes, lactate, glucose and haemoglobin.
- The instructor sets the acid–base pair, carbon-dioxide tension and bicarbonate, and can also set the potassium and the glucose.
- The pH and base-excess controls move that pair. A pH change moves whichever of the two the instructor picks; base excess shares one control with bicarbonate under two labels, so the two cannot disagree.
- Never authored at all: the pH, the base excess, the anion gap and the calculated oxygen saturation. They are recomputed from the measured set every time the result is drawn.
- So a NAP gas cannot be internally inconsistent in the way a hand-typed one can.
- Lactate can be changed under More values.
- Sodium, chloride and haemoglobin come from the chosen picture and are not separately adjustable.
The equations
The pH comes from Henderson–Hasselbalch in its clinical form, the standard base excess from the Van Slyke equation, the anion gap from the convention that excludes potassium, and the saturation from Severinghaus’ standard oxyhaemoglobin dissociation curve.
- Each is cited below. The base-excess, saturation and anion-gap expressions were each checked against the published source rather than against a secondary summary.
- The pH equation is Henderson–Hasselbalch in the standard clinical form given in the acid–base review cited below.
Standard base excess, and why haemoglobin is not an input
The base excess NAP shows is the standard one: the Van Slyke equation evaluated at the haemoglobin of the extracellular fluid rather than of blood.
- The haemoglobin the instructor authors deliberately does not feed it.
- Actual base excess, computed at the patient’s own haemoglobin, is a different measure; NAP reports the standard one.
Details
- Why the extracellular fluid: it makes the number describe the extracellular space and stay steady when the haematocrit moves.
Where the model stops
The saturation uses the standard curve at pH 7.40 and 37 °C, uncorrected.
- There is no alveolar–arterial gradient and no inspired-oxygen context.
Details
- Why uncorrected: a correction with a remembered coefficient would be worse than none.
Arterial and venous
A gas can be taken arterially or venously; the venous sample is the same authored patient read differently.
- pH and carbon-dioxide tension carry the published venous offsets; the oxygen tension is a typical peripheral value rather than a conversion.
- Arterial and venous carbon-dioxide tensions are not comparable: the meta-analysis below finds a bias interval that crosses zero, so a real venous value can sit either side of its arterial pair.
- So a venous sample is its own result, never something convertible into an arterial one, and the card says so on its face.
- The venous card shows no calculated saturation at all, because none of it is derived from the arterial pair.
- The optional highlight marks the same abnormalities either way: switching how the blood was drawn does not change what is wrong with the person.
A result slip, not a second patient
A released gas is frozen at the moment it is taken, like a printed slip: it does not evolve, and it is not coupled to the monitor in either direction.
- Editing the gas never moves the patient’s displayed saturation, and the patient never rewrites the gas.
- Where the two disagree, NAP preserves the disagreement rather than quietly reconciling it: the instructor is the physiology, the same rule that governs every other NAP module.
- Reading that disagreement is the instructor’s job; NAP does not annotate it.
Reference bands, and the highlight
An optional teaching highlight marks each value that falls outside its reference band.
- With one exception these are ordinary adult teaching intervals rather than sourced values, listed below as still-open provenance; the anion-gap band is the one carrying a citation.
- Real intervals are analyser-dependent and vary between laboratories, so no single set would be right everywhere.
- The comparison is made against the value as printed, in whatever units the room is set to, not the value as stored.
- So the card cannot show a number inside its band with an “outside” arrow beside it, or outside it with none.
Units describe the reader
Tensions can be read in kilopascals or millimetres of mercury, glucose in millimoles per litre or milligrams per decilitre, and haemoglobin in grams per litre or per decilitre.
- These are properties of the room reading the result, not of the sample: settings a room carries and can change with a result already on screen, not values frozen into the gas when it was taken.
Grounded in 6 sources
Siggaard-Andersen, 1977 — The van Slyke equation (Scand J Clin Lab Invest Suppl 146:15–20)
The standard-base-excess form NAP ships. The paper states the equation with haemoglobin as a free variable; solved at the extracellular-fluid haemoglobin of 3.1 mmol/L it reproduces both of NAP’s constants exactly, making it standard base excess.
Morgan, Clark & Endre, 2000 — Accuracy of base excess: an in vitro evaluation of the Van Slyke equation (Crit Care Med 28:2932–6)
That Van Slyke base excess tracks metabolic acid–base status in vitro, “little affected by large simultaneous alterations in P(CO2), or by very low hemoglobin concentrations similar to that used to calculate standard base excess”: support for a fixed extracellular haemoglobin.
Severinghaus, 1979 — Simple, accurate equations for human blood O₂ dissociation computations (J Appl Physiol 46:599–602)
The oxygen saturation NAP calculates from the oxygen tension. NAP ships the published expression unmodified; the paper reports it fitting the standard human dissociation curve to within ±0.0055 fractional saturation.
NAP uses that standard curve, uncorrected for temperature and pH.
Kraut & Madias, 2007 — Serum anion gap: its uses and limitations in clinical medicine (Clin J Am Soc Nephrol 2:162–74)
The potassium-excluded anion gap NAP derives, defined there as chloride and bicarbonate subtracted from sodium.
And the caution NAP repeats rather than papers over: the normal value “can vary widely, reflecting both differences in the methods that are used to measure its constituents and substantial interindividual variability”.
Berend, de Vries & Gans, 2014 — Physiological approach to assessment of acid–base disturbances (N Engl J Med 371:1434–45)
Henderson–Hasselbalch in its clinical form, and the expected-compensation relationships used to build the preset pictures, so each hangs together as a recognisable clinical story rather than a set of independently plausible numbers.
Byrne et al., 2014 — Peripheral venous and arterial blood gas analysis in adults: are they comparable? (Respirology 19:168–75)
How a venous sample is presented. The meta-analysis puts arterial pH about 0.03 above peripheral venous, but finds venous and arterial carbon-dioxide tensions not comparable: the bias’s prediction interval crosses zero.
NAP uses the offsets to generate a plausible venous sample from one authored patient, never as a conversion, and says so on the card. The unreliability is the teaching point.
Session record and debrief
An optional, timestamped record of what happened in the room (what learners did on the monitor, what the instructor set, and moments the instructor chose to mark), laid out afterwards as a timeline for whatever debrief the facilitator runs.
Validation status
Literature-informed · descriptiveWhat this covers
What NAP records by itself
With recording switched on, NAP writes down what its instructor consoles can see; recording is off by default.
- From the room: a learner’s shocks and pacing attempts as the monitor reported them, CPR as the instructor set it, therapy results, and presets and adenosine outcomes the instructor applied.
- From a scenario and the monitors: a scenario’s start, steps, shocks and end, and each monitor’s own trend of what its screen showed.
- One clock: each is stamped against one clock the room’s instructor consoles share, and labelled with where it came from.
- Where it is kept: only on the instructors’ devices.
What the instructor marks
What the monitor cannot see (a call for help, a leader identified, a concern raised, a drug given) the instructor taps from an editable list, or types.
- The starter list is NAP’s own, informed by resuscitation-reporting templates and team-behaviour marker systems, and is meant to be edited.
- NAP borrows their words; it does not rate against them, and nothing is scored or counted.
- A mark is a record of what the team did and changes nothing on the monitor.
What the debrief page shows
After the run, the record is laid out as a timeline: each row with its time and where it came from, each scenario step with the values it aimed at, and the moments the instructor flagged or noted.
- Beneath it, a trend of what one monitor showed, sampled as a bedside monitor stores its trend, never the values the instructor set, and a band naming the rhythm the room was set to over the run.
- The page names no debriefing tool or framework as its structure; the record supports whatever approach the facilitator uses.
- NAP does not itself teach, assess, or conduct a debrief.
Why a text timeline
NAP records an ordered text timeline rather than video: a choice about privacy, size and what a monitor can honestly know.
- The research on debriefing does not establish that a timestamped record improves learning, and NAP does not claim it does.
Grounded in 8 sources
Sawyer, Eppich, Brett-Fleegler, Grant & Cheng, 2016 — More than one way to debrief: a critical review of healthcare simulation debriefing methods (Simul Healthc 11:209–17)
That a facilitator-guided debrief after the event may use several conversational structures, and that adjuncts sit beside them. Grounds NAP’s place as an adjunct that supplies a record and leaves the structure to the facilitator.
Cheng, Eppich, Grant, Sherbino, Zendejas & Cook, 2014 — Debriefing for technology-enhanced simulation: a systematic review and meta-analysis (Med Educ 48:657–66)
Across 177 studies, video-assisted debriefing showed a negligible, non-significant difference from debriefing without video in the four studies that compared them.
It compared video with no video and did not study text timelines: NAP’s text record is a product decision this source does not contradict, not evidence for the record’s educational value.
Fletcher et al., 2003 — Anaesthetists’ Non-Technical Skills (ANTS): evaluation of a behavioural marker system (Br J Anaesth 90:580–8)
The vocabulary (task management, team working, situation awareness, decision making) the guide uses to explain why team behaviours are worth marking.
NAP’s rows are not ANTS elements and are not mapped to them; ANTS needs trained raters and NAP rates nothing.
Cooper et al., 2010 — Rating medical emergency teamwork performance: development of the Team Emergency Assessment Measure (TEAM) (Resuscitation 81:446–52)
Vocabulary for the arrest-team setting: leadership, teamwork and task management.
The same limit as ANTS: no rows mapped, nothing rated.
Nolan et al. for ILCOR, 2019 — Utstein Resuscitation Registry Template for In-Hospital Cardiac Arrest, update (Resuscitation 144:166–77)
The process elements (the team called, first documented rhythm, defibrillator applied, ROSC) that NAP’s arrest rows are adapted from.
Adaptations: a registry’s time of arrest is not “arrest recognised”, and any ROSC is not “ROSC recognised by the team”. A real-arrest registry template; it says nothing about simulation or debriefing.
Cheng et al. for the American Heart Association, 2018 — Resuscitation Education Science: educational strategies to improve outcomes from cardiac arrest (Circulation 138:e82–122)
Only that feedback and debriefing are named elements of resuscitation education in a professional-body statement.
A scientific statement, not a trial.
INACSL Standards Committee, 2025 — Healthcare Simulation Standards of Best Practice: The Debriefing Process (Clin Simul Nurs 105:101775)
That the debriefing process (its framework, facilitation, confidentiality and psychological safety) is a standards-recognised practice.
All of it is the facilitator’s; NAP supplies a record to it and never a product notice.
INACSL Standards Committee, 2021 — Healthcare Simulation Standards of Best Practice: The Debriefing Process (Clin Simul Nurs 58:27–32)
The predecessor of the 2025 revision, cited for lineage; current-standard claims cite the 2025 revision.
Where provenance is still open
Values still marked citation-to-verify
Some exact NAP-authored values are not yet strongly enough sourced to support a fidelity claim, and are marked as citation-to-verify in the canonical bibliography.
- Adult scenarios: exact scenario / recovery values and timing arcs.
- Alarms: exact thresholds and offsets.
- Processed EEG: exact transition constants.
- Paediatrics: the exact defaults, which remain authored teaching values rather than citable reference standards.
- Blood gases: both the individual preset values and all but one of the reference bands the optional highlight judges against, which are ordinary adult teaching intervals rather than sourced ones.
- Deliberately compressed timings, such as a shortened NIBP cycle, are product conventions, labelled as such rather than retrofitted with a clinical citation.
The clearest example: EtCO₂ tempo
The clearest example is how fast EtCO₂ follows a change in perfusion: NAP moves it several times faster than the published time course.
- Why: so that a class watching a resuscitation in the default CPR quality mode sees the consequence of better or worse compressions while it is still the thing being discussed.
- A teaching decision about tempo, taken deliberately and recorded as one. NAP does not claim that EtCO₂ responds this quickly in patients.
- No resuscitation guideline specifies a response time: neither AHA 2020 Part 3 nor ERC 2021 ALS contains one (both below).
- The direction and the mechanism are grounded; the speed is chosen for the lesson.
Panchal et al., 2020 — AHA 2020 Part 3 (doi:10.1161/CIR.0000000000000916)
Checked specifically for an EtCO₂ response time during resuscitation: it contains none.
Soar et al. for the European Resuscitation Council, 2021 — Adult advanced life support guideline
Checked specifically for an EtCO₂ response time during resuscitation: it contains none.
Evidence informs; face-validation confirms.
A module may only make a fidelity claim after independent clinicians review its rendered behaviour, transitions and teaching interpretation against a documented checklist.
Until then, everything here is provenance for the design, not proof of clinical realism.
The sources here are drawn from NAP’s canonical bibliography, which is kept in the repository with every link and re-checked as modules change.