Preoperative Hypercapnia as a Predictor of Hypotension during Anesthetic Induction in Lung Transplant Recipients

Abstract

【Objective】 To determine the incidence and predisposing factors of hypotension during anesthetic induction in lung transplant recipients. 【Design】 Retrospective study. 【Setting】 University hospital. 【Participants】 Patients who underwent lung transplantation between 2008 and 2013 (n = 68). 【Interventions】None. 【Measurements and Main Results】 The authors analyzed the mean arterial pressure (MAP) from administration of anesthetic drugs to 10 minutes after endotracheal intubation (ie, the anesthetic induction) among participants who underwent lung transplantation. Patients were considered to have clinically significant hypotension (CSH) when the following criteria were fulfilled: An MAP decrease of>40% from baseline and MAP of<60 mmHg. Overall, 41.2% of patients experienced CSH during the induction of anesthesia. The preoperative partial pressure of carbon dioxide (PaCO2) was significantly higher in patients who experienced CSH during anesthetic induction than in those who did not (p = 0.005). Preoperative PaCO2 predicted the development of CSH during anesthetic induction (area under the curve = 0.702; p = 0.002), with an optimal cut-off point of 55 mmHg determined by maximizing the Youden index. The incidences of CSH during anesthetic induction for patients with (PaCO2≥55) and without (PaCO2<55) preoperative hypercapnia were 75.0% (95% confidence interval [CI] [53.8-89.2]) and 30.8% (95% CI 26.4-37.3), respectively. After adjustment for known predicting factors, the odds ratio for the relationship between preoperative hypercapnia and CSH during anesthetic induction was 12.54 (95% CI 3.10-66.66). 【Conclusions】 Hypotension during anesthetic induction is common in lung transplant recipients, and is independently predicted by preoperative hypercapnia.