Reexpansion pulmonary edema: A rare complication of pneumothorax drainage

Abstract

Among all the noncardiac causes of pulmonary edema, unilateral reexpansion pulmonary edema is one of the rarest complication of expansion of a collapsed lung. It is largely unknown and a potentially fatal complication. We present the case of a 51-year-old gentleman who presented to our emergency department with shortness of breath. X-ray revealed significant right-sided pneumothorax with associated collapse of the right lung. An intercostal tube was inserted into the right 5th intercostal space and a repeat X-ray revealed well-expanded lung field. Soon, the patient developed increased shortness of breath and hypoxia. Repeat X-ray was suggestive of pulmonary edema. He was started on noninvasive positive pressure ventilation and responded well to it. Emergency physicians should have a high index of suspicion and initiate early management of reexpansion pulmonary edema in patients suffering from pneumothoraces which have undergone drainage.

Introduction

Among all the noncardiac causes of pulmonary edema, unilateral reexpansion pulmonary edema (REPE) is one of the rarest complication ofexpansion of a collapsed lung.[1] REPE occurring after a pneumothorax has been drained is still under recognized and under reported.[2] Since REPE has a high mortality rate of 21%, its recognition at the right time cannot be emphasized enough.[3] Here, we present a case of unilateral ipsilateral REPE after chest tube insertion in a patient with massive pneumothorax.

Case Report

A lean 51-year-old gentleman presented to our emergency department (ED) with shortness of breath since 3 days. The patient had no comorbidities and was a nonsmoker. On arrival, his blood pressure was recorded as 136/90 mmHg, heart rate of 103/min, respiratory rate of 19/min, oxygen saturation (SPO2) on room air of 98%, random blood sugar of 104 mg/dL, and was afebrile. On systemic examination, the patient was found to have reduced breath sounds in the right hemithorax. No adventitious sounds could be heard. The rest of the systemic examination was normal. Routine blood investigations revealed a total leukocyte count of 21.4 × 10⁹/L with a neutrophil count of 84%. Chest X-ray revealed significant right-sided pneumothorax with associated collapse of the right lung [Figure 1].

An intercostal tube (FR 28) was inserted into the right 5^th intercostal space. A repeat X-ray revealed well-expanded lung field [Figure 2]. The patient was maintaining normal vitals when after 1 h, he suddenly developed severe shortness of breath and became hypoxic with an SPO2 of 74% on room air and tachypneic with a respiratory rate of 33/min. On examination, the patient had developed coarse right-sided crepitations. He was started on high-flow oxygen via face mask, and an urgent X-ray chest, electrocardiogram (ECG), and blood gas were ordered. The blood gas revealed Type 1 respiratory failure with a PO₂ of 41 mmHg. ECG revealed a normal sinus rhythm and X-ray was suggestive of alveolar opacities in the right upper and mid zones suggestive of unilateral pulmonary edema [Figure 3]. The patient was started on bilevel positive airway pressure (BiPAP) support which brought the SPO₂ to 92%

Based on the findings and clinical presentation, a diagnosis of spontaneous right pneumothorax with reexpansion unilateral pulmonary edema was made. The patient was transferred to the intensive care unit and kept on BiPAP support. After 6 days, the patient's X-ray revealed a normal study and the patient was discharged home in a stable condition.

Discussion

Our patient suffered from REPE after a chest tube was inserted to manage the spontaneous massive pneumothorax he had. The patient had become tachypneic and hypoxic, but responded well to noninvasive ventilation. REPE is usually a self-limiting disorder and mostly requires airway and circulation management. However, a 21% mortality rate cannot be ignored and emergency physicians should be able to recognize this seemingly benign yet fatal complication.

The exact mechanism of REPE is still not understood. REPE appears to be due to increased permeability of the pulmonary vasculature. High protein content found in edema fluid indicates that it is leakiness of the capillaries rather than an increased hydrostatic pressure difference that leads to the edema. Lung injury could also occur due to reperfusion and oxygen free radical formation in the collapsed lung.[4] Young adults, female sex, greater degree and longer duration of lung collapse, a reexpansion of lung in <10 min, use of negative pressure during treatment, and evacuation volume more than 2000 ml have been shown to be at a higher risk for developing reexpansion pulmonary edema. Signs and symptoms include sudden onset of breathing difficulty, tachypnea, hypoxia, and tachycardia, usually within 1–2 h of intercostal chest drainage. No studies have been performed comparing the different methods of draining a pneumothorax, but some papers may suggest that the technique of draining a pneumothorax might influence the development of REPE.[5] It is recommended not to drain more than 1 liter of fluid or air at once and to use water valves instead of suction. 1200–1800 mL should be the maximum volume of air or fluid to be drained as per estimates. It is advised to stop drainage when the patient starts coughing, as it might be a first sign of pulmonary edema formation.[6] The treatment of REPE is supportive and consists of oxygen, BiPAP, or CPAP support. Verhagen et al. described a case of REPE in a traumatic pneumothorax. The patient was kept on CPAP and recovered within a week.[6] In some cases, intubation and mechanical ventilation with positive end expiratory pressure (PEEP) will be necessary. Since the cause of pulmonary edema is not cardiogenic, use of diuretics needs to be avoided.

Conclusion

REPE remains a largely unknown complication, but is potentially fatal. It occurs in <1% of cases where a lung has been rapidly expanded postchest tube drainage.[7] It would be prudent for emergency physicians to suspect and initiate early management of REPE in patients suffering from pneumothoraces which have undergone drainage.

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.

Sarda S is the principal author. All other coauthors have contributed toward the critical feedback, literature review, and proof reading for the manuscript.

None declared.

None declared.

References

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