Interactive Ventilator

An anesthesia workstation simulator for medical students learning ventilator and anesthetic physiology. This is a work-in-progress. We are constantly improving the model, fine-tuning dynamics, and pursuing clinical reality.

GE Datex-Ohmeda · Patient Monitor
II
ABP
SpO₂
CO₂
NIBP
118/72
(88)
mmHg
TEMP
36.8
°C
GAS / AGENT
MAC0.95
EtO₂52%
Sevo2.1%
Aspect Medical · BIS Monitor
EEG
δ 1–4 Hzθ 4–8 Hzα 8–13 Hzβ 13–30 Hz
Dräger Zeus · Ventilator
Paw
cmH₂O
Flow
L/min
Vol
mL
TVset
480
mL
TVexp
478
mL
RR
12
br/min
MV
5.8
L/min
PIP
22
cmH₂O
Pplat
18
cmH₂O
PEEP
5
cmH₂O
Pmean
10
cmH₂O
FiO₂
50%
EtCO₂
36
mmHg
autoPEEP
0
cmH₂O
τ exp
0.25
s
P-VLoop
▸ Insp ◂ Exp
VC-CMV TV 480 mL · RR 12 · PEEP 5 · FiO₂ 50%
Ventilator Settings
480
12
5
50
1.0
Patient Physiology
50
5
200
0
Active Alarms
No active alarms
Train-of-Four 4/4
No Block ↗ Open tutorial
NMT Monitor · Train-of-Four Peripheral Nerve Stimulator — Educational Tutorial
TOF Count
4/4
TOF Ratio
1.00
Block Depth
No Block
No meaningful neuromuscular blockade. Normal response.
Block State
Drug Demonstration
What is Train-of-Four?
Four supramaximal stimuli at 2 Hz are applied to a peripheral nerve (usually the ulnar nerve at the wrist). The resulting muscle twitches are measured. Fade — where later twitches are progressively weaker — is the hallmark of nondepolarizing blockade. The TOF ratio (T4 ÷ T1) below 0.9 indicates residual paralysis even when all four twitches are visible.

Monitor Tutorial

5-Lead ECG Monitoring in the OR

HR72bpm
ST II0.0mm
ST V50.0mm
Regular rate and rhythm. Clear P wave before every QRS. Rate 60–100 bpm. Normal intraoperative finding.

Key Teaching Points

  • HR is derived from the RR interval — the distance between two consecutive R peaks
  • Lead II is the primary intraoperative lead for rhythm detection; P waves are largest here
  • V5 is the most sensitive single lead for detecting myocardial ischemia
  • ST changes >1 mm (elevation or depression) suggest ischemia — inform your attending
  • Always confirm a monitor rhythm with a pulse check before treating

Monitor Tutorial

Arterial Line Waveform Interpretation

SBP118mmHg
DBP72mmHg
MAP88mmHg
Normal arterial waveform. Brisk upstroke, clear dicrotic notch, normal pulse pressure (~46 mmHg). Waveform is reliable.

Key Teaching Points

  • Waveform shape reflects stroke volume + vascular resistance in real time
  • MAP is most clinically relevant — goal ≥65 mmHg to ensure organ perfusion
  • The dicrotic notch marks aortic valve closure and separates systole from diastole
  • Pulse pressure (SBP–DBP) reflects stroke volume; wide = hyperdynamic, narrow = low SV
  • A dampened waveform may be a line problem — flush and check before treating the patient

Monitor Tutorial

Pulse Oximetry and Pleth Waveform

SpO₂99%
PI2.4%
Normal pleth. Good amplitude, regular peaks, strong perfusion index. SpO₂ 99% is accurate and reliable.

Key Teaching Points

  • SpO₂ reflects oxygen saturation — it does NOT reflect ventilation (use EtCO₂ for that)
  • Pleth amplitude is your perfusion indicator — a flat wave is a red flag regardless of the number
  • "Good number ≠ good perfusion" — vasoconstricted patients can read 99% while hypoperfused
  • SpO₂ lags actual arterial saturation by 30–60 seconds — act early if the trend is downward
  • A noisy or absent waveform means the reading is unreliable — reposition the probe first

Monitor Tutorial

BIS & Processed EEG in the OR

BIS48
SR0%
EMG40dB
General anesthesia — BIS in the target range (~40–60). Low suppression ratio; EMG quiet. EEG shows mixed frequencies without burst-suppression pattern.

Spectral heatmap (δ, θ, α, β)

The strip under the EEG shows how relative power in each band changes over time. Open the interactive viewer to scroll through clinical scenarios and explore each band.

Key Teaching Points

  • BIS is a proprietary index (0–100) derived from EEG — lower values generally reflect deeper hypnotic effect; typical general anesthesia targets are often 40–60 (follow institutional protocol)
  • Suppression ratio (SR) reports the proportion of “flat” EEG — elevated SR indicates profound cortical suppression; interpret alongside hemodynamics and agent dosing
  • EMG from frontal electrodes can reflect facial muscle tone or artifact (cautery, poor contact) — high EMG may falsely lower BIS or mask a light state
  • BIS is not a substitute for clinical assessment; false highs and lows occur (e.g., EMG, ketamine, nitrous, neurological conditions)
  • Use BIS as one part of multimodal monitoring together with vital signs, end-tidal agent, and clinical signs of depth and awareness risk

Monitor Tutorial

Spectral EEG heatmap (δ · θ · α · β)

Each horizontal band is a frequency range. Time scrolls left to right (newer toward the right). Color intensity uses the same scale in every row: dark / cool = lower relative power, bright / warm = higher (see the scale at the right of the heatmap). Click δ, θ, α, or β for a band note, then Clinical scenario for how the pattern fits the setting.

Time →

Wave description

Clinical scenario

Bands are approximate; real devices differ in filtering and scaling. Use the heatmap as context for depth and artifact, not as a stand-alone diagnosis.

Ventilator Tutorial

Paw, Flow, Volume & P–V Loop

One-breath traces use the same simplified physics as the main simulator. Change mode, timing, and lung mechanics, or pick a preset, and watch how pressure, flow, volume, and the P–V loop respond.

Paw
cmH₂O
Flow
L/min
Volume
mL

Dashed lines represent baseline normal physiology (C = 50 mL/cmH₂O, R = 8 cmH₂O/L/s) at the same ventilator settings.

Monitor Tutorial

Capnography & Gas Monitoring

EtCO₂36mmHg
RR12/min
I — Dead space II — Upstroke III — Plateau ↓ Inspiration

The Capnogram

  • Phase I — Inspiratory baseline: dead space ventilation, CO₂ ≈ 0 mmHg
  • Phase II — Expiratory upstroke: mixing of dead space and alveolar gas, CO₂ rises sharply
  • Phase III — Alveolar plateau: CO₂-rich gas; EtCO₂ is measured at the very end of this phase
  • Downstroke — Inspiration begins; fresh gas washes CO₂ back to zero immediately
  • Normal EtCO₂: 35–45 mmHg. Reflects both ventilation and perfusion

Scenario Debrief

Strengths

    Areas to Review

      High-Yield Teaching Points