Preoxygenation and Maternal Apneic Desaturation
Abstract Number: 233
Abstract Type: Original Research
Introduction: A recent closed claims analysis reveals that difficult intubation accounts for 25% (7/28) of general anesthetic related maternal mortality. After 1999, newer supraglotic airway rescue devices may have had an impact. Can hemoglobin desaturation during apnea be modeled to illustrate the importance of preoxygenation to buy precious time when rigid laryngoscopy fails?
Methods: A modified differential equation that accounts for decreased maternal hemoglobin and FRC but increased blood volume and oxygen consumption (that decrease during induction of anesthesia) was used to graph the rate of fall of hemoglobin saturation.
Results & Discussion: Preoxygenation can buy from 4-8 minutes of time before arterial oxygen saturation falls to very low levels, enough time to insert an alternative airway device.
References: 1) Farmery and Roe. BJA. 1996; 76:284-291.
2) Davies et al. Anesthesiology. 2009; 110:131-9.