Advanced Monitoring · advanced haemodynamics
Run the advanced-haemodynamics module.
How to place invasive lines, enable and operate the arterial, central-venous and pulmonary-artery channels, wedge safely, and present the picture, using the controls exactly as they appear in the app.
Before you start
- Controller
- Monitor
Use an up-to-date browser on a reasonably capable phone, tablet or laptop: the surface draws live pressure traces and reads the device core continuously.
- Present on a wide screen where possible: the arterial, CVP and PA traces and the numeric column are easiest to read together.
- The module is deliberately inactive until you select Haemo on the Advanced tab.
- A fresh session shows the standard monitor with no invasive channel: every line, arterial included, starts off.
Engage haemodynamics
- Controller
Open Advanced and select Haemo to engage haemodynamics with a coherent default picture.
- The pinned rail switches between Blood gas, Drifts, Haemo and EEG. Each shows its room state; one panel appears at a time.
- The Haemo rail reads until selected, then the placed lines and mode, or the line-fault count. Faults at the top of the panel sets a line fault.
- Selecting Haemo engages the module; after a patient reset the panel shows Start until you tap it. Blood gas and EEG have their own panels, so preparing a gas leaves the lines alone.
- Nothing shows on the learner monitor until a line is both sited here and displayed there (the two-layer rule below).
- There is no separate off switch on the current controller. Ending or starting a new session clears the module and returns the room to the standard monitor.
Placing lines (the room layer)
- Controller
Which invasive lines the scenario has sited is the instructor (room) layer, set in Advanced → Haemo under Line placement.
- Arterial line — Off / Attached. Attaching it unlocks a cardiac output, index and stroke volume read from the arterial line, so a room without a PA catheter can still teach flow.
- Central venous (CVP) — Off / Sited.
- PA catheter (PAP + wedge) — Off / Sited. Siting it is what makes the PA trace, the wedge and the thermodilution cardiac output available.
- A preset sites the lines it needs; the arterial toggle stays as you set it.
Cardiac output, by method
- Method-labelled. With a PA catheter it reads the thermodilution figure; from the arterial line alone it reads the pulse-contour estimate, tagged (PC): the same one patient shown from a different line.
- One authored value. The (PC) figure is the one authored cardiac output shown under the pulse-contour label, not a value NAP computes from the waveform.
- No invented difference. NAP labels which method you are reading and never invents a difference between them.
- The pulse-contour value is a trend, not a calibrated measurement.
Enabling displays and the two-layer rule
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- Monitor
A channel shows a trace only when a line is both sited (instructor) and displayed (learner).
- Enabling a display is a learner control on the monitor: open the monitor's display-settings gear (⚙) and, under Invasive lines, turn on ART, CVP or PA. Placing the line is the room layer.
- All three channels are off by default, arterial included, so a plain monitor never sprouts empty invasive lanes.
Advanced tab → Line placement. Arterial: Off / Attached. CVP and PA: Off / Sited.
Display-settings gear (⚙) → Invasive lines → ART, CVP or PA. Off by default.
- not sited + not shown → the channel is absent.
- not sited + shown → , never an invented trace. This is deliberate: the display never fabricates data.
- sited + not shown → nothing on this monitor; another monitor in the room may still be showing it.
- sited + shown → the trace and its numerics.
Zeroing, levelling and fast-flush
- Monitor
These are learner device operations in the monitor's display-settings gear (⚙), under Invasive lines, one row per channel.
- Zero to atmosphere. Press Zero to reference the transducer against room air, as at the bedside.
- Level the transducer. Raise or lower it relative to the phlebostatic axis. A mis-levelled transducer shifts the displayed pressure by the hydrostatic offset (about ±20 cm range), a common and teachable setup error.
- Fast-flush. Press Flush to deliver a fast-flush, and use it to demonstrate a square-wave test and the line's dynamic response.
These change how one monitor reads the pressure, not the patient. Two monitors can differ in zero and level without changing the shared patient, and none of it is saved into a scenario.
The wedge press-and-hold
- Monitor
Wedge from the monitor, with the PA catheter sited and its display on.
- Press and hold Wedge (hold). While held, the balloon inflates, the button reads , and the PA trace collapses to the lower-amplitude wedge (PAOP) tracing.
- Read the value and release. Releasing, or the monitor losing focus, deflates immediately.
- on hold Balloon inflates
The PA trace collapses to the wedge tracing. Read the value now.
- 10 s Over-wedge warning
The button changes to . You are past the point where the value should already have been read.
- 15 s Hard auto-deflation
NAP deflates the balloon itself and notes . A fresh press is required to re-inflate.
The timer lives in the monitor's device model, so it cannot leak across a reload: a freshly loaded monitor is never stuck inflated.
Linked and manual modes
- Controller
The mode decides whether the haemodynamic numbers move together or are set one by one.
- Linked The default, coherent teaching mode: the primitive targets plus the shared patient's BP and heart rate drive MAP, mPAP, CI, SV, SVR and PVR together.
- Manual Intentionally decouples every number, to build a deliberate teaching contradiction. The controller shows an unmistakable banner while it is on.
A manual picture is a constructed teaching case. Identify it as such, and never describe it as the patient's physiology.
A demonstration viewer's screen carries a MANUAL badge; the learner monitor itself shows no badge, so say it out loud.
Presets
- Controller
One tap sets a coherent whole patient: the invasive targets and the lines it needs, plus a matching sinus rhythm, HR, BP, SpO₂, RR and EtCO₂.
- Normal A coherent baseline set.
- Cardiogenic High wedge, low CO / CI, high SVR.
- Septic High CO, low SVR, high SvO₂.
- Hypovolaemia Low filling pressures, high SVR, low CO.
- Massive PE / RV High CVP, wedge well below PA pressure, very high PVR.
- Tamponade Blunted CVP y-descent, diastolic equalisation and pulsus paradoxus.
- Pulmonary HTN Chronically high PA pressure with a normal wedge.
How a preset applies
- The vitals come with the targets, so a septic picture never sits beside a normal heart rate.
- Left as you set them: your line faults, respiratory modifier and mode.
- In linked mode the derived numbers recompute from those primitives and that patient.
- Presets and target changes ramp over the transition time you choose, or jump straight there on Instant.
- Nothing moves on its own afterwards: the patient stays exactly where you put it until you change it.
Every preset installs a sinus rhythm along with its invasive targets. If your patient is in VT or AF, applying one replaces that too: set the rhythm afterwards if you need it back.
Line faults and respiration
- Controller
Tap Faults in the Haemo top bar to stage a fault on the arterial, CVP or PA line.
- Dynamic response The first button group on each line's row: Normal, Overdamped or Underdamped. A non-normal response distorts the trace and the numbers read from it.
- Condition The second group on the row: Good, Air bubble, Kinked or Disconnected. A disconnected line flattens its waveform to atmospheric while the true patient pressure is unchanged.
- Respiratory variation Spontaneous or Positive pressure: a bounded, visible swing on the venous and pulmonary traces to teach the effect. It is a waveform modifier, not a ventilator model.
What to look for
- A damped line shows no badge. Unlike and , which announce themselves, it looks like a plausible trace: recognising it from the waveform is the point of the exercise.
- A pronounced narrowing of the pulse appears on the arterial and pulmonary traces under the tamponade picture, falling on inspiration (the pulsus paradoxus), or under positive-pressure ventilation, where the swing reverses with the breath.
A line fault is a technical fact about the line, not the physiology: it distorts the trace and the numbers without moving the patient.
Good to know
- How the swing is sized: the ordinary swing moves the whole trace up and down by a set amount; the narrowing is scaled to each channel's own pulse pressure rather than to a fixed number of millimetres.
Reading the CVP trace
- Monitor
The venous trace carries teaching the numbers alone cannot.
What to show
- In complete heart block, watch the CVP beside the ECG. The atria march on their own clock, and the CVP reads the same beat timeline the ECG's P waves come from.
- Cannon a-waves: when an atrial beat falls in the quarter-second after an R wave, while the ventricle is contracting, that beat shows an accentuated a-wave, lined up with the rhythm above it.
- Point at the P wave, then at the wave it made. The same dissociation in ventricular tachycardia does the same thing.
- The magnitudes are teaching values: NAP makes no claim to validated waveform fidelity.
Good to know
- Why it lines up: the alignment is a consequence of how the module is built, rather than a picture drawn for the occasion; the timing comes from the same cardiac events the rest of the monitor is drawn from.
The lines during CPR
- Controller
- Monitor
An arrest suppresses the patient's own blood pressure, so the invasive numbers go blank: the picture of a pulseless patient, not a broken line.
- Start compressions and the arterial trace and numeric come back as the compression-generated pressure. It rises and falls with the compression quality you set, and blanks again the moment compressions stop.
- On the monitor and pacer screens. The defib and AED screens leave the arterial line out; it returns when the learner goes back to the monitor.
The CPP tile
- CPP needs two lines. With an arterial line and a central line both in place, a coronary-perfusion-pressure tile appears beside the other numbers; with only one there is no tile, because a difference needs two numbers.
- A target, not a verdict. It marks the level historically associated with return of circulation. The tile changes weight, colour and gains a dot when compressions reach it, and stays plain when they do not.
- Nothing turns red: poor compressions are something to improve, not an alarm.
- Good compressions sit comfortably above the level and poor ones well below: a direct way to show a class why compression quality is the intervention.
- It uses the relaxation pressures: the arterial diastolic minus the floor of the CVP trace (the CVP tile shows that trace's mean), so a mis-levelled or damped line moves it too.
Changing quality mid-arrest
- Quality change speed: on the Therapy tab, beside Good / Poor, it decides how a Good↔Poor switch lands: Instant, 1 s or 3 s.
- Pick a ramp rather than Instant and the pressures sweep to their new level instead of jumping, all reading the one compression-quality value you changed.
- Choose Instant and pressures and EtCO₂ step together, for when you simply want the state set.
- You change Quality
Therapy tab, beside Good / Poor. Pick Instant, 1 s or 3 s.
- Pressures move together
The arterial trace, the CVP and PA compression pulses and the CPP tile all sweep over the transition you chose: they read the one quality value.
- EtCO₂ is still travelling
The EtCO₂ number and the capnogram plateau keep settling for roughly another twenty seconds after the pressures have arrived. This is intended, not a stuck reading.
EtCO₂ arrives late, on purpose
- At the bedside the arterial line answers a change in compression quality within one to three compressions, while EtCO₂ has to re-equilibrate a whole body's worth of CO₂ through the lungs, so it confirms the change rather than announcing it.
- The teaching point: improve the compressions, the pressure answers now, EtCO₂ agrees a few seconds later.
- The lag is a delay on your change and nothing else. The compression quality is yours to set; EtCO₂ settles exactly on the value your setting implies and then stops.
- Nothing evolves on its own, as everywhere else in NAP: the patient never drifts toward or away from a return of circulation by itself.
NAP runs the EtCO₂ catch-up faster than a real patient would, on purpose, so the ordering is visible without holding up the scenario.
Presenters and observers
- Monitor
- Viewer
A presenter switches a monitor to the haemodynamics surface to show the class.
- One monitor slot. The same tab consumes one monitor slot, so switching surface does not open a second connection.
- Read-only observers follow the presented surface: the same traces and numbers, including a live preset change and a wedge inflated on the presenter, reproduced rather than re-simulated.
- Room-shared patient state (mode, targets, placement, line faults, respiration) is the same for everyone.
- Device-local view preferences (display on/off, zero, level) belong to each monitor and can differ without changing the patient.
Worked scenarios
- Controller
- Monitor
Four patterns to build on the controller and read on the monitor; the cardiogenic and PE pictures are also selectable in the interactive example on the module overview.
- Line-setup error. Leave a line unsited while learners turn on its display, or have them mis-level the transducer: they should recognise or a hydrostatic offset, and set the picture up correctly before reading a number.
- LV failure (cardiogenic). The Cardiogenic preset: a high wedge with a low CO / CI and a high SVR: the failing left ventricle backing up while resistance climbs to defend the pressure.
- RV failure / PE. The Massive PE / RV preset: a high CVP and PA pressure but a low wedge and a high PVR. The right-versus-left discriminator: a wide PA-diastolic-to-wedge gradient points at the pulmonary circulation, not the left heart.
- Mixed shock. Start from the Septic preset, then add a cardiac component yourself (a rising wedge, a falling CO and SvO₂, and an SVR that is no longer ultra-low) and have learners re-reason as the numbers move.
Troubleshooting
- Controller
- Monitor
What to check when the picture is not what you expect.
- The module seems inactive. Select Haemo on the controller's Advanced tab, or tap Start in its panel; the rail stops reading . Selecting another segment does not engage haemodynamics.
- A lane stays blank. The two-layer rule: the line must be sited on the controller and its display enabled by the learner on the monitor.
- A channel shows NO TRANSDUCER. The learner enabled the display but the instructor has not sited that line. Site it in the Advanced tab, and the same lane flips to a live trace.
- A pressure reads higher or lower than expected. Check the transducer level and zero on the monitor: a mis-levelled transducer shifts the number by the hydrostatic offset. Also check for a line fault (damped or disconnected) staged on the controller.
- The wedge will not stay inflated. That is by design: it warns at about 10 s and hard auto-deflates at about 15 s. Read the value quickly; a fresh press re-inflates.
- PAP shows a single mean, not sys / dia. A non-perfusing rhythm has no PA pulse, so the trace flattens and the numeric collapses to the mean beside it, the same way CVP always shows one mean.
- The presenter and an observer differ. View preferences (display on/off, zero, level) are device-local, so they can differ without being a fault; the shared patient state is the same for both.
Limits
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- Monitor
The module is educational simulation, not clinically validated and not equivalent to any real monitor.
- Not a diagnostic or treatment device, and not a substitute for bedside measurement.
- Cardiac output is an instructor-set primitive, not a computed one. The thermodilution and pulse-contour (PC) readouts both surface that same authored value, labelled by method; neither is a real thermodilution or continuous-cardiac-output computation.
- Out of scope: invasive intracranial, ventilator and anaesthetic-machine models.
- In a paediatric room the numbers rescale: body-surface area comes from the selected band's representative patient, cardiac output is class-scaled and CI is derived from CO ÷ BSA, so the same preset pictures run at class-scaled targets.
- These paediatric values are plausible teaching numbers, not a validated paediatric-haemodynamics claim; the pressure-waveform shapes are the same adult-pattern generators at paediatric targets.