Background: The Negative Pressure Pulmonary Edema (NPPE) is a multifactorial condition,reported in patients after general anesthesia. Despite being uncommon (0.05-0.1%),it is a potentially life-threatening emergency that can be fatal in 11-40%.It characteristically occurs after endotracheal intubation, but has already been described after Laringeal Mask Airway (LMA) use(1). As its occurrence is under-reported, our aim is to point out the importance of an expeditious diagnosis.
Case report: 24-yr-old woman (50Kg, 1,60m), presented to the ambulatory surgery center for an axillary ganglia excisional biopsy. Patient's medical history was relevant only for a recurrent spontaneous pneumotorax. Unknown allergies.Normal pre-operative study.
Inhalatory anesthesia,atraumatic LMA place.Anesthesia and surgical procedure were uneventful. Transferred to Postanesthesia Care Unit (PACU), spontaneously ventilating (SV).
Ten minutes later, marked respiratory distress, tachypnea, cyanosis, accessory muscle utilization and significant arterial oxygen desaturation (40%)-treated by positive-pressure mask ventilation until improved peripheral oxygen saturation. Physical examination revealed bilateral diffuse crackles and respiratory failure type I (PaO2 52mmHg). Chest radiograph with bilateral pulmonary infiltrates without pneumotorax signs.
Transferred to Intermediate Care Unit,conscious, hemodynamically stable, SV with supplemental oxygen,SpO2>90%. An echocardiograph(normal) and an angio-computed tomography (acute pulmonary edema in resolution, no signs of thromboembolism) were performed. Progressive recovery without non-invasive pressure support, discharged from hospital on the 4th postoperative day. Follow-up in 8 weeks.
Discussion: When considering differential diagnosis of acute-onset perioperative pulmonary edema, NPPE was considered despite the absence of evident high airway obstruction. However, the clinical presentation and its rapid improvement are consistent with the diagnosis. Given the increasing use of LMA, similar episodes can become recurrent, being crucial its prompt recognition.
References:
1. Int J Crit Sci,2012 May-Aug;2(2):98-103
Learning points: We should be alert for the possibility of NPPE ocurrence
