Sleep Apnea Simulation
Group 10 · BME 3261C Biofluid Mechanics
1
How it happens
2
What it does
3
Our solution
▶ Guided tour
ⓘ Model notes
⛶
Upper airway
· side view, sleeping
Asleep
airway open
Narrowing
snoring, flow-limited
Obstruction
effort, no airflow
Arousal
airway reopens
Gasp
recovery breaths
Sleep-lab strip
· last 90 s
Why it collapses
· pressure vs closing pressure
SpO₂
96
%
PaCO₂
43
mmHg
Effort peak
6
cmH₂O
Events
0
/
0
per h
Patient airway
Healthy
Mild
Moderate
Severe
Sleep stage
NREM
REM
CPAP
Off
10 cmH₂O
Speed
1×
2×
4×
⚙ Physiology traits
❚❚ Pause
Four OSA traits (Eckert et al. 2013)
Airway collapsibility, Pcrit
Dilator-muscle responsiveness
Arousal threshold (effort)
Ventilatory loop gain
Anatomy (Pcrit) is only one of four causes. Muscle response, arousal threshold and loop gain vary from patient to patient.
Patient
Healthy
Mild
Moderate
Severe
CPAP pressure (treated night)
10 cmH₂O
↻ Replay
Slow
Normal
Fast
Night report
AHI = apneas + hypopneas per hour of sleep. ODI = ≥3% oxygen dips per hour. Severity bands follow AASM: <5 normal · 5–15 mild · 15–30 moderate · ≥30 severe.
Why it matters · untreated OSA is associated with
Airflow path
· one design change
CPAP pressure
10.0 cmH₂O
Expiratory relief
3.0 cmH₂O
Tidal volume
0.50 L
Breathing rate
15 /min
Airway resistance R
3.0 cmH₂O·s/L
Lung compliance C
0.10 L/cmH₂O
Relief valve ON
Reset to deck values
Comfort vs therapy
· sweep the relief
One breath
· flow, mask pressure, muscle effort
Work-of-breathing loop
Before → after
Close ✕