⚠SpO₂ falling — patient agitated. Assess the patient and circuit.
SpO₂
76%
HR
122bpm
MAP
72mmHg
Temp
37.3°C
ECMO Circuit
Blood flow (Qb)4.2 L/min
Gas flow (sweep)6 L/min
FiO₂ blender1.0
Pre-oxygenator SaO₂55%
Post-oxygenator SaO₂99%
Ventilator (lung rest)
ModePC-AC
FiO₂ (vent)0.5
PC above PEEP10 cmH₂O
PEEP12 cmH₂O
RR (observed)28/min
Vt (measured)520 mL
ABG (arterial)
pH
7.33
PaO₂
45 mmHg
PaCO₂
40 mmHg
HCO₃⁻
21 mEq/L
Lactate
2.5 mmol/L
Hgb
10.8 g/dL
Patient Context
Patient49F, 68 kg
DiagnosisCOVID-19 ARDS
ECMO dayDay 5
CannulaFem-Fem bilateral venous
VasopressorsNE 0.03 µg/kg/min
SedationPropofol (light)
Clinical Decision Required — Case 5
SpO₂ has fallen from 84% to 76% over 30 minutes. The circuit is intact and the oxygenator post-SaO₂ is 99%. The nurse reports the patient appears to be waking — respiratory rate is 28/min and tidal volumes have risen to 520 mL (was 300 mL). Pre-membrane SaO₂ has dropped to 55%. No circuit alarms. What is the primary driver and what do you do first?