Evaluation of Reperfusion Pulmonary Edema by Extravascular Lung Water Measurements After Pulmonary Endarterectomy

Objectives: Reperfusion pulmonary edema is a specific complication of pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension. Extravascular lung water measurement may be valuable for diagnosing reperfusion pulmonary edema. The primary objective of this study was to describe and assess the clinical significance of extravascular lung water variations after pulmonary endarterectomy. Design: Prospective observational study. Setting: Nineteen-bed cardiothoracic ICU. Patients: Consecutive patients who were hemodynamically stable after pulmonary endarterectomy were divided into two groups based on whether their preoperative pulmonary vascular resistance indicated severe or nonsevere chronic thromboembolic pulmonary hypertension (> 900 or ≤ 900 dynes·s/cm5, respectively). Interventions: Hemodynamic variables obtained by right heart catheterization and transpulmonary thermodilution measurements were recorded 1 hour, 1 day, and 2 days after pulmonary endarterectomy. Extravascular lung water was indexed to predicted body weight (EVLWPBW). Measurements and Main Results: We studied 31 patients. Overall, 26 patients (84%) experienced reperfusion pulmonary edema during the first 72 hours after pulmonary endarterectomy. EVLWPBW significantly increased between the first hour after pulmonary endarterectomy and day 2 (10.2 ± 2.6 vs 11.4 ± 3.6; p = 0.03). EVLWPBW measured at the first hour after pulmonary endarterectomy is closely associated with reperfusion pulmonary edema occurrence in the next 48 hours (area under the receiver-operating characteristics curve = 0.88 ± 0.07). EVLWPBW correlated with duration of mechanical ventilation (ρ = 0.59; p < 0.0001) and ICU stay (ρ = 0.52; p < 0.0001). Patients with severe chronic thromboembolic pulmonary hypertension (n = 15) had higher EVLWPBW values at day 2 compared with those without (n = 16) (13.2 ± 3.6 vs 9.7 ± 2.7 mL/kg; p = 0.004). Cardiac output was measured simultaneously by pulmonary artery catheter and aortic transpulmonary thermodilution on 92 occasions; agreement was good, with a bias of 0.50 ± 0.95 L/min (95% CI, –1.36–2.36). Conclusions: Accurate extravascular lung water measurements were obtained after pulmonary endarterectomy. Extravascular lung water may prove valuable for diagnosing reperfusion pulmonary edema after pulmonary endarterectomy and had prognostic value. Extravascular lung water values were significantly higher in patients with severe compared with nonsevere chronic thromboembolic pulmonary hypertension.