Tag: Venous air embolism

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The risk of intraoperative venous air embolism from neurosurgical procedures performed in the lounging position

J Neurosurg 142:797–807, 2025

The study investigated the risk of venous air embolism (VAE) during neurosurgery in the lounging position, finding no permanent sequelae or fatal events. Despite a 51.4% VAE detection rate, no hemodynamic instability occurred, suggesting experienced teams can safely use this position.

Study Overview

• Objective: Assess venous air embolism (VAE) risk and outcomes in lounging position neurosurgery.

• Study Design: Retrospective analysis of 1000 patients from 2010 to 2020.

• Primary Focus: VAE incidence, severity, and associated complications.

Key Findings

• VAE Detection: 51.4% of patients experienced VAE, with no grade 5 events.

• Complications: 0.3% developed acute respiratory distress syndrome (ARDS) linked to VAE grade.

• No Permanent Sequelae: No patients suffered permanent neurological deficits from VAE.

Patient Demographics

• Mean Age: 47.7 years; 56.5% female.

• Common Pathologies: 94.9% had posterior fossa tumors, mainly vestibular schwannomas.

Surgical Approach and Positioning

• Lounging Position: Feet elevated above head to improve venous return.

• Surgical Benefits: Reduced intracranial pressure and improved surgical field visibility.

Risk Factors and Outcomes

• High-Grade VAE: Associated with older age and lower BMI.

• No PFO Contraindication: PFO is not linked to paradoxical embolism in this cohort.

• Outcome Predictors: Preoperative KPS score is most relevant for clinical outcomes.

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Contemporary analysis of the intraoperative and perioperative complications of neurosurgical procedures performed in the sitting position

J Neurosurg 127:182–188, 2017

Historically, performing neurosurgery with the patient in the sitting position offered advantages such as improved visualization and gravity-assisted retraction. However, this position fell out of favor at many centers due to the perceived risk of venous air embolism (VAE) and other position-related complications. Some neurosurgical centers continue to perform sitting-position cases in select patients, often using modern monitoring techniques that may improve procedural safety. Therefore, this paper reports the risks associated with neurosurgical procedures performed in the sitting position in a modern series.

METHODS The authors reviewed the anesthesia records for instances of clinically significant VAE and other complications for all neurosurgical procedures performed in the sitting position between January 1, 2000, and October 8, 2013. In addition, a prospectively maintained morbidity and mortality log of these procedures was reviewed for instances of subdural or intracerebral hemorrhage, tension pneumocephalus, and quadriplegia. Both overall and specific complication rates were calculated in relation to the specific type of procedure.

RESULTS In a series of 1792 procedures, the overall complication rate related to the sitting position was 1.45%, which included clinically significant VAE, tension pneumocephalus, and subdural hemorrhage. The rate of any detected VAE was 4.7%, but the rate of VAE requiring clinical intervention was 1.06%. The risk of clinically significant VAE was highest in patients undergoing suboccipital craniotomy/craniectomy with a rate of 2.7% and an odds ratio (OR) of 2.8 relative to deep brain stimulator cases (95% confidence interval [CI] 1.2–70, p = 0.04). Sitting cervical spine cases had a comparatively lower complication rate of 0.7% and an OR of 0.28 as compared with all cranial procedures (95% CI 0.12–0.67, p < 0.01). Sitting cervical cases were further subdivided into extradural and intradural procedures. The rate of complications in intradural cases was significantly higher (OR 7.3, 95% CI 1.4–39, p = 0.02) than for extradural cases. The risk of VAE in intradural spine procedures did not differ significantly from sitting suboccipital craniotomy/craniectomy cases (OR 0.69, 95% CI 0.09–5.4, p = 0.7). Two cases (0.1%) had to be aborted intraoperatively due to complications. There were no instances of intraoperative deaths, although there was a single death within 30 days of surgery.

CONCLUSIONS In this large, modern series of cases performed in the sitting position, the complication rate was low. Suboccipital craniotomy/craniectomy was associated with the highest risk of complications. When appropriately used with modern anesthesia techniques, the sitting position provides a safe means of surgical access.

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Venous air embolism in the sitting position in cranial neurosurgery

Acta Neurochir (2017) 159:339–346

There is an ongoing debate about the sitting position (SP) in neurosurgical patients. The SP provides a number of advantages as well as severe complications such as commonly concerning venous air embolism (VAE). The best monitoring system for the detection of VAE is still controversial.

Methods: In this retrospective analysis we compared 208 patients. Transesophageal echocardiography (TEE) or transthoracic Doppler (TTD) were used as monitoring devices to detect VAE; 101 cases were monitored with TEE and 107 with TTD.

Results: The overall incidence of VAE was 23% (TTD: 10%; TEE: 37%), but the incidence of clinically relevant VAE (drop in end-tidal carbon dioxide above 3 mmHg) was higher in the TTD group (9 out of 17 VAE, 53%) compared to the TEE group (19 out of 62 VAE, 31%). None of the patients with recorded VAE had clinically significant sequelae.

Conclusions: In this small sample we found more VAE events in the TEE group, but the incidence of clinically relevant VAE was rare and comparable to other data. There is no consensus in the definition of clinically relevant VAE.

 

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