Acute pulmonary edema after low-level air embolism during craniotomy. Case report

Acute pulmonary edema due to occult air embolism detected on an automated anesthesia record: illustrative case

BACKGROUND

The authors report a case of venous air embolism (VAE) during a pediatric posterior fossa craniotomy with resulting pulmonary edema requiring postoperative ventilation. Pulmonary edema is a known but rare complication of VAE, and diagnosis and treatment are discussed.

OBSERVATIONS

The embolism was undetected during the surgical procedure, and the first clinical sign of respiratory decompensation appeared an hour after the initial insult, with imaging suggesting acute pulmonary edema. A transient but significant end-tidal carbon dioxide decrease was detected on postoperative review of the anesthesiology record.

LESSONS

This report highlights an uncommon sequela of VAE and the importance of post hoc automated record review for intraoperative event analysis.

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

Venous air embolism (VAE) is a well-known complication of sitting position neurosurgery which most characteristically manifests as mild to severe hemodynamic alterations. Development of pulmonary edema is a known, though infrequent, manifestation of VAE. We report here the occurrence of acute pulmonary edema without accompanying hemodynamic changes in a patient undergoing retromastoid craniotomy and tumor decompression in the sitting position. The patient required supportive treatment and elective ventilation for 11 days before the edema resolved. He also developed significant postoperative thrombocytopenia which though, was self-limiting. Thus, VAE may manifest with atypical manifestations like pulmonary edema and thrombocytopenia that can significantly contribute to postoperative patient morbidity.

Pulmonary oedema following venous air embolism during transsphenoidal pituitary surgery

Venous air embolism (VAE) is a well known complication in procedures where the operative field is above the level of the heart. Acute pulmonary oedema after a large air embolus occurring during neurosurgery is also a recognized phenomenon. However, pulmonary oedema following repeated episodes of VAE in sublabial transsphenoidal (SLTS) surgery for pituitary adenoma has never been reported. We describe a case of VAE in a 65 year old male undergoing SLTS surgery for pituitary adenoma. Following this, the patient had pulmonary oedema which resolved on supportive treatment. Pulmonary oedema as a result of VAE may go unrecognised intraoperatively but can lead to a significant postoperative morbidity. Early suspicion and recognition of VAE and institution of aggressive treatment will help to avoid fatal consequences.

Severe intraoperative air embolism during convexity meningioma surgery in the supine position. Case report

BACKGROUND

Acute venous air embolism (AE) is a well-known intraoperative complication of neurosurgical procedures, especially during surgical procedures performed in the sitting position, but it is a rare complication in the supine position. A case of a patient who developed an AE during a supratentorial craniotomy in the supine position is presented and the literature is reviewed.

CASE DESCRIPTION

A 45-year-old man had a large left frontal convexity meningioma. He was operated upon and, during craniotomy in the supine position, suffered a massive episode of air embolism with severe respiratory and hemodynamic changes. The AE episode occurred while we were cutting the bone for the craniotomy before turning the bone flap. Because the patient was bleeding profusely, the bone flap was quickly removed to achieve hemostasis. Aspiration of irrigant into the cut bone surfaces through several venous diploic channels in the bone edges was observed. The procedure was terminated when hemostasis was achieved. The meningioma was successfully removed in a second operation.

CONCLUSION

We think that our case should serve to warn the neurosurgical community about the risk of AE in supratentorial procedures in the supine or semisitting positions when preoperative radiological imaging studies show the presence of important venous channels in relation to the site of the tumor.

Clinical and radiologic features of pulmonary edema

Pulmonary edema may be classified as increased hydrostatic pressure edema, permeability edema with diffuse alveolar damage (DAD), permeability edema without DAD, or mixed edema. Pulmonary edema has variable manifestations. Postobstructive pulmonary edema typically manifests radiologically as septal lines, peribronchial cuffing, and, in more severe cases, central alveolar edema. Pulmonary edema with chronic pulmonary embolism manifests as sharply demarcated areas of increased ground-glass attenuation. Pulmonary edema with veno-occlusive disease manifests as large pulmonary arteries, diffuse interstitial edema with numerous Kerley lines, peribronchial cuffing, and a dilated right ventricle. Stage 1 near drowning pulmonary edema manifests as Kerley lines, peribronchial cuffing, and patchy, perihilar alveolar areas of airspace consolidation; stage 2 and 3 lesions are radiologically nonspecific. Pulmonary edema following administration of cytokines demonstrates bilateral, symmetric interstitial edema with thickened septal lines. High-altitude pulmonary edema usually manifests as central interstitial edema associated with peribronchial cuffing, ill-defined vessels, and patchy airspace consolidation. Neurogenic pulmonary edema manifests as bilateral, rather homogeneous airspace consolidations that predominate at the apices in about 50% of cases. Reperfusion pulmonary edema usually demonstrates heterogeneous airspace consolidations that predominate in the areas distal to the recanalized vessels. Postreduction pulmonary edema manifests as mild airspace consolidation involving the ipsilateral lung, whereas pulmonary edema due to air embolism initially demonstrates interstitial edema followed by bilateral, peripheral alveolar areas of increased opacity that predominate at the lung bases. Familiarity with the spectrum of radiologic findings in pulmonary edema from various causes will often help narrow the differential diagnosis.

Fatal postoperative pulmonary edema: pathogenesis and literature review

STUDY OBJECTIVES

Pulmonary edema is a known postoperative complication, but the clinical manifestations and danger levels for fluid administration are not known. We studied (1) 13 postoperative patients (11 adult, 2 pediatric) who developed fatal pulmonary edema, and (2) one contemporaneous year of inpatient operations at two university teaching hospitals to determine the clinical manifestations, causes, epidemiology, and guidelines for fluid administration.

DESIGN

Retrospective analysis of 13 patients with fatal postoperative pulmonary edema and one contemporaneous year of major inpatient surgery.

PATIENTS AND METHODS

Thirteen patients had net fluid retention of at least 67 mL/kg in the initial 24 postoperative hours and developed pulmonary edema. Ten were generally healthy while three had serious associated medical conditions.

MEASUREMENTS AND RESULTS

There was no measurement, laboratory value, or clinical finding predictive of impending pulmonary edema. The most common clinical manifestation following the onset of pulmonary edema was cardiorespiratory arrest (n = 8). Patients had metabolic acidosis (pH = 7.15 +/- .33), hypoxia (PO2 = 45 +/- 18 mm Hg), and normal electrolytes. The diagnosis of pulmonary edema was established by chest radiograph and confirmed by autopsy and pulmonary artery pressure (21 +/- 4 mm Hg). The mean net fluid retention was 7.0 +/- 4.5 L (90 +/- 36 mL/kg/d) and exceeded 67 mL/kg/d in all patients. Autopsy revealed pulmonary edema with no other cause of death. Among 8,195 major operations, 7.6% developed pulmonary edema with a mortality of 11.9%. Extrapolation to the 8.2 million annual major surgeries in the United States yields a projection of 8,000 to 74,000 deaths.

CONCLUSIONS

Pulmonary edema can occur within the initial 36 postoperative hours when net fluid retention exceeds 67 mL/kg/d. There are no known predictive warning signs and cardiorespiratory arrest is the most frequent clinical presentation. The monitoring systems currently in use neither detect nor predict impending pulmonary edema, and as yet, there are no known panic values for excessive fluid administration or retention.