Precordial Doppler monitoring and pulse oximetry during cesarean delivery: detection of venous air embolism.

Venous air embolism (VAE) is a potential but rare complication of cesarean delivery that can be associated with morbidity and death. Uterine sinuses are susceptible to the entrance of air during cesarean delivery. To define the incidence of VAE and its relation to arterial oxygen saturation (SaO2) and consequent electrocardiographic (ECG) changes, a prospective study was undertaken in which precordial Doppler monitoring was conducted during cesarean delivery. Concomitant, SaO2 and ECG were recorded in 78 patients. Fifty-one of 78 (65%) of the subjects had Doppler changes consistent with VAE. Of these, 37 patients (72%) showed a decreased SaO2, (average decline 5.2%). The remainder of the patients with Doppler changes showed no SaO2 change. Twenty of the patients with Doppler changes and decreased SaO2 complained of chest pain and dyspnea. Three of these patients exhibited ECG changes including ST segment depression. Although all ECG changes resolved spontaneously without sequelae, the potential clearly existed for life threatening embolic events. Thus, precordial Doppler monitoring of cesarean delivery patients demonstrated a surprisingly high incidence of Doppler changes consistent with VAE. Some episodes were associated with a significant reduction in SaO2 and rarely with ECG changes.