Clinical and experimental studies identified large tidal volume (Vt) as an important risk factor for development of acute respiratory failure and acute lung injury (ALI). Patients undergoing pneumonectomy may be at particular risk for adverse ventilator settings during surgery. We hypothesized that larger intraoperative Vt may be associated with postoperative respiratory failure in patients undergoing pneumonectomy.
We reviewed the electronic medical records of all patients having elective pneumonectomy at our institution from January 1999 to January 2003. In addition to intraoperative Vt, we collected data on demographics, comorbities, neoadjuvant chemotherapy and radiotherapy, pulmonary function tests, operative procedures, duration of surgery and intraoperative fluid administration. Respiratory failure was defined as the need for mechanical ventilation for greater than 48 hours postoperatively or the need for reinstitution of mechanical ventilation after extubation.
Of 170 consecutive pneumonectomy patients, 30 (18%) developed post-operative respiratory failure. Causes of respiratory failure were ALI in 15 patients (50%), cardiogenic edema in 5 (17%), pneumonia in 7 (23%), bronchopleural fistula in 2 (7%) and pulmonary thromboembolism in 1 (3%). Patients who developed respiratory failure were ventilated with larger intraoperative Vt than those who did not (median 8.3 vs 6.7 mL/kg predicted body weight, p<0.001, Figure). In a multvariate logistic regression analysis, larger intraoperative Vt (odds ratio 1.45 for each mL/Kg of predicted body weight, 95% CI 1.12-1.92,) and larger volumes of intraoperative fluid (odds ratio 1.47 per liter of fluid infused, 95% CI=1.00-2.18), were identified as risk factors of postoperative respiratory failure. The 60-day mortality rate after pneumonectomy was 7.6% (13 of 170 patients), with respiratory failure accounting for 46% of the deaths. Patients who developed post-operative respiratory failure had longer hospital length of stay (31.5 ± 10.4 days vs. 7.8 ± 1.3 days; p <0.001).
Large intraoperative Vt and larger volumes of intravenous fluids during pneumonectomy are associated with an increased risk of post-operative respiratory failure.
Potentially harmful intraoperative ventilatory settings, in particular large tidal volumes, should be avoided during pneumonectomy.
Evans Fernández, None.