Co-administration of ephedrine prevents reductions in cardiac output and systemic oxygen delivery secondary to lung compression maneuvers during one-lung ventilation, without reducing arterial oxygenation

Purpose We previously showed that compression of the nondependent lung during one-lung ventilation (OLV) in patients undergoing esophagectomy improves arterial oxygenation but impairs cardiac output (CO) and systemic oxygen delivery (DO 2 ). The objective of this study was to test the hypothesis that the combination of nondependent lung compression and ephedrine improves arterial oxygenation without compromising DO 2 . Methods Twenty patients undergoing esophagectomy through a right thoracotomy were studied. Under general anesthesia, a left-sided double-lumen tube was placed, and the dependent lung was mechanically ventilated with a tidal volume of 8 ml/kg and a fraction of inspiratory oxygen of 0.8 during OLV. When nondependent lung was compressed by surgeons to improve surgical exposure, a randomly determined intravenous bolus of either ephedrine 4 mg (group E) or an identical volume of saline (group S) was administered. Arterial blood was sampled during two-lung ventilation (TLV), at 10 min of OLV (OLV1), and 5 min after nondependent lung compression (OLV2). Results The initiation of OLV resulted in a significant drop in PaO 2 at OLV1 (group E, 136 ± 69 mmHg; group S, 138 ± 83 mmHg; P