Prevalence of Negative-Pressure Pulmonary Edema at an Orthopaedic Hospital

W. Christopher Patton, MD, Champ L. Baker, Jr., MD


J South Orthop Assoc. 2000;9(4) 

In This Article

Abstract and Introduction

Negative-pressure pulmonary edema (NPPE) occurs when a large, negative intrathoracic pressure is generated against an obstructed upper airway, causing fluid to shift into the lung interstitium. Young, healthy, athletic male patients appear to be at increased risk for this disorder, but the prevalence in orthopaedic surgery patients has been unknown. We retrospectively reviewed the charts of 14 patients (11 male, 3 female) with NPPE at our institution over a 15-year period. The patients had 11 different surgical procedures; 16,653 similar procedures were done during this time. The overall prevalence of NPPE (<0.1%) was not significantly different between male and female patients. Patients with NPPE were significantly younger than those without NPPE. If NPPE is recognized promptly and treated appropriately with intravenous diuretic and oxygen therapy, most patients respond well. Physicians should be vigilant to the potential for NPPE in young, otherwise healthy patients after general anesthesia.

Negative-pressure pulmonary edema (NPPE) is a noncardiogenic pulmonary edema in which a large, negative intrathoracic pressure generated against an obstructed upper airway results in the shift of fluid into the interstitium of the lungs. Signs and symptoms of NPPE include tachypnea, shortness of breath, pulmonary rales, frothy sputum production, decreased oxygen saturation, and evidence of upper airway obstruction. Chest radiographs may show pulmonary edema. Since 1977, when Oswalt et al[1] first described three cases of acute pulmonary edema after upper airway obstruction, the exact pathophysiologic mechanism has been debated.[2,3] Furthermore, the patients at risk for NPPE have been discussed by many authors and include those with sleep apnea and chronic upper airway obstruction, as well as athletic males and awake infants who have been given muscle relaxants.[2,4,5,6,7]

The first report of NPPE in the orthopaedic literature was by Anderson et al,[4] who noted three cases of acute pulmonary edema after extubation in young, athletic male patients. They suggested that young athletes might be at increased risk for laryngospasm-induced pulmonary edema. Holmes et al[5] reported on eight male patients with postoperative pulmonary edema over a 2-year period and theorized that young, healthy, athletic males were at increased risk for this condition. Goitz et al[6] described four cases of NPPE in athletic male patients during 6 years of outpatient procedures at the Sports Medicine and Hand Surgery Service at the University of Virginia. They concluded that "postextubation pulmonary edema in healthy, young athletic adults following routine orthopaedic procedures can be an alarming consequence of upper airway obstruction if not properly recognized."[6]

Deepika et al[8] reported 30 cases of NPPE over a 4-year period and found a prevalence of 0.094% at a large metropolitan hospital covering a wide range of surgical specialties. They found that NPPE occurred more frequently in healthy, middle-aged male patients having head and neck surgery than in patients having general anesthesia at their hospital. No statistical data were given comparing the ages of those who had NPPE with those who did not.

A further review of NPPE revealed only scattered case reports and small series. The prevalence of this potentially dangerous postoperative condition involving orthopaedic surgery patients is unknown. To our knowledge, the mean age of adults who had NPPE has not been compared with that of patients who had similar procedures but did not have NPPE. The purpose of our study was to determine the prevalence of NPPE at a single hospital specializing in orthopaedic surgery over a 15-year period.