Acute pulmonary edema after low-level air embolism during craniotomy

Abstract

Acute pulmonary edema after a large air embolus occurring during neurosurgery is a recognized phenomenon. The authors describe the course of a 76-year-old man who presented with noncardiogenic pulmonary edema shortly after undergoing resection of a high convexity meningioma. Transthoracic Doppler sonography, however, showed no evidence of a large intraoperative emboli; the evidence for ongoing but low-magnitude air embolus included visualization of bone aspiration of irrigant before bone-edge waxing, transient intraoperative declines in end-tidal CO2 tension, and an increase of the fraction of inspired oxygen to maintain adequate saturation after removal of the craniotomy flap. There was no hemodynamic instability noted. The airspace disease was self-limited and resolved on supportive treatment after approximately 1 week, as would be expected for pulmonary edema caused by a single large intravenous air embolus. The authors present this case as the first report of pulmonary edema resulting from low-level air embolus occurring during craniotomy. This situation may go unrecognized intraoperatively but can cause the same significant postoperative morbidity as larger, more easily identified air emboli.

Clinical and Radiologic Features of Pulmonary Edema

“…Air may enter into the lowpressure venous system when a pressure gradient favors such access. This occurs most frequently during neurosurgical procedures performed with the patient in the sitting position and during manipulation or placement of central venous lines (77). In addition, two patients at our institution inadvertently underwent massive air embolization with volumes approaching 1 L. This occurred at the end of a cardiac surgical procedure due to mismanagement of a new flushing system for the extracorporeal circulation device.…”

“…Other, nonmechanical factors (eg, liberation of oxygen radicals from neutrophils) also contribute to the disruption of the capillary endothelium. Macromolecules, proteins, and blood cells may then enter the interstitial and alveolar spaces (77). This creates a variable pathologic picture that ranges from mild interstitial edema to hemorrhagic airspace consolidations.…”

“…The embolized air bubbles cause mechanical obstruction of the pulmonary microvasculature due to the relatively low absorption coefficient of air (76,77). These collections of air create turbulent flow, which favors platelet aggregation, fibrin formation, and vasoconstriction, thus increasing the pressure exerted on the vessel wall.…”

Venous Air Embolism in Deep Brain Stimulation

“…During awake stereotactic DBS and lesion surgeries, VAE has been reported, and has been associated with the clinical manifestation of a cough [5,6,[10][11][12] . VAE may lead to serious consequences such as pulmonary edema, respiratory failure, and even death [12][13][14] . No study to date has prospectively analyzed this phenomenon in DBS or attempted to estimate its inci- 26 dence during DBS surgery.…”

Acute pulmonary edema and thrombocytopenia following venous air embolism during sitting position neurosurgery

“…[1] However, equally serious, though infrequently reported adverse effects of VAE are acute pulmonary edema without cardiovascular instability[2345678] and post-VAE thrombocytopenia. [910] We report here the rare occurrence of both these problems after VAE in a patient undergoing suboccipital craniotomy and tumor decompression in the sitting position.…”