Failure to oxygenate during cardiopulmonary bypass: Approach to management

Art: arterial; CPB: cardiopulmonary bypass; gm: grams; Hgb: hemoglobin; HPE: high pressure excursion; IV: intravenous; LPM: liters per minute; NMBAs: neuromuscular blocking agents; O₂: oxygen; PaO₂: partial pressure of arterial oxygen; PvO₂: partial pressure of venous oxygen; Sat: saturation; SvO₂: mixed venous hemoglobin saturation; Ven: venous.

* Refer to UpToDate content on maintenance of anesthesia during CPB.

¶ Refer to UpToDate content on weaning from CPB. Temporary weaning from CPB after resuming controlled ventilation may be an appropriate option while troubleshooting and/or replacing the oxygenator if the aortic cross-clamp has been removed, systemic temperature is >34°C, and ventricular function is adequate. Permanent weaning form CPB may be appropriate if the procedure has been completed and the patient is normothermic.

Δ Refer to UpToDate content on general management of patients undergoing cardiac surgery.

◊ The Fick equation for oxygen consumption, also known as the oxygen transfer equation, can be used to determine if problems with oxygenation are patient-related or oxygenator-related:

• Oxygen consumption/transfer = (Art O₂ content – Ven O₂ content) × (10) × (Flow [LPM])
• Art O₂ content = [(Art sat %) × (1.34 mL O₂) × (Hgb g%)] + [(PaO₂) × (0.003)]
• Ven O₂ content = [(Ven sat %) × (1.34 mL O₂) × (Hgb g%)] + [(PvO₂) × (0.003)]
• Maximum value = 350 mL at 6 LPM gas flow with 12 g% Hgb at normothermia

§ Refer to UpToDate content regarding systemic anticoagulation during CPB.