Discussion

Unilateral postoperative pulmonary edema is an underreported adverse event after a minimally invasive cardiac surgical procedure that combines right minithoracotomy with cardiopulmonary bypass. We sought to characterize its incidence, risk factors, and morbidity.

We conducted a retrospective case-control study of all cardiac surgical procedures that combined right-sided minithoracotomy with cardiopulmonary bypass at our institution over 8 consecutive years. Unilateral postoperative pulmonary edema was defined on the chest radiograph taken on the first postoperative day as relatively increased opacification of the right versus left hemithorax involving at least 20% of the hemithorax, not better explained by atelectasis. Baseline characteristics, potential risk factors, and outcomes were subject to univariable and multivariable analysis.

Radiographs were available for 277 of 278 patients; of those, 68 (25%) met our definition of unilateral postoperative pulmonary edema. Patients with unilateral postoperative pulmonary edema had higher mortality and were more likely to have a lower postoperative PaO₂/F_IO₂ ratio, to require vasoactive medications and mechanical ventilation for longer than 24 hours, and to have longer lengths of stay in the intensive care unit and the hospital. Unilateral postoperative pulmonary edema was independently associated with chronic obstructive pulmonary disease (odds ratio [OR] 4.79; 95% confidence interval [CI] 1.28 to 18.0; p = 0.02); pulmonary hypertension, right-ventricular dysfunction, or both (OR 2.92; 95% CI 1.41 to 6.03; p = 0.004); and increasing cardiopulmonary bypass time (OR 1.019; 95% CI 1.011 to 1.027 per additional minute; p <0.001).

Unilateral postoperative pulmonary edema after minimally invasive cardiac surgical procedures is common, carries significant morbidity, and has identifiable risk factors. Further research is needed to enable a better understanding of the pathophysiology and clinical implications of unilateral postoperative pulmonary edema.

Mujer de 36 años que fue sometida a una resección de timoma gigante que ocupaba gran parte del hemitórax izquierdo. Tras la resección del tumor y la insuflación del pulmón izquierdo apareció un edema pulmonar por reexpansión precoz. Se trató con diuréticos, corticoides y se mantuvo la ventilación mecánica. La paciente evolucionó favorablemente. El edema pulmonar por reexpansión es una complicación poco frecuente, pero con una alta mortalidad. Es fundamental conocer los factores implicados en su etiopatogenia. El diagnóstico y tratamiento se deben realizar de forma inmediata.

A 36 year-old woman who was subjected to resection of a giant thymoma that occupied a large area of the left hemithorax. After resection of the tumour and insufflation of the left lung there was pulmonary oedema due to early re-expansion. She was treated with diuretics and corticoids and was kept on mechanical ventilation. The patient progressed favourably. Although pulmonary oedema due to re-expansion is an uncommon complication it has a high mortality. It is essential to be aware of the factors involved in its aetiopathogenesis. It should be diagnosed and treated immediately.

Reexpansion pulmonary edema (REPE) is a rare yet sometimes fatal complication associated with the treatment of lung diseases such as pleural effusion, pneumothorax, and hemothorax. The current study summarizes our experience with REPE for a 3-year period.

We prospectively collected demographic and clinical data on consecutive patients presenting to an academic university-based emergency department with spontaneous pneumothorax that was treated with closed thoracostomy for a 3-year period.

Eighty-four study patients were enrolled between December 2002 and September 2005. Reexpansion pulmonary edema developed in 25 of 84 (29.8% [95% confidence interval, 21.0-40.2]) patients. Many cases of REPE were small and asymptomatic and only diagnosed on computed tomography of the chest. There was only one death (1.2% [95% confidence interval, A to B]). Reexpansion pulmonary edema was associated with patients with larger pneumothoraces without fibrotic changes and with patients with hypoxia and fibrotic changes. Classic REPE as seen on chest radiograph was 16 (19.0%) in 84 patients. Diffuse REPE as seen only on computed tomography and involved more than 1 lobe was 1 (1.2%) in 84 patients. Isolated REPE as seen only on computed tomography and limited to lesser than 1 lobe was 8 (9.5%) in 84 patients.

The rate of REPE after tube thoracostomy of spontaneous pneumothorax is greater than previously reported and often asymptomatic. The risk of developing REPE is greater with larger pneumothorax, especially in patients without fibrotic lung changes, and with hypoxia in patients with fibrotic changes.