gms | German Medical Science

Objective: Venous air embolism (VAE) is a potentially serious complication of the semi setting position. In this study, we wanted to investigate the Safety of the semi-sitting position analyzing over a 20-years period.

Methods: The incidence of VAE and its perioperative management were analyzed retrospectively in a consecutive series 755 patients who were operated between 1996 and 2016. The occurrence of relevant VAE was defined by detection of bobbles in Doppler/transesophageal echocardiography (TEE), decrease of PtCO² (4 mmHg) and/or an unexplained drop of arteria blood pressure (systolic > 10mmHg).

Results: There were 347 women and 408. Mean age at surgery was 49 years (range 1-87 years). Medical condition according to ASA was classified as I =386 (51.1%), II=303 (40.1%) and III=66 (8.8%), mean body mass index 26.07 kg / m² (range 11-58 kg / m²). Surgery was performed for infratentorial lesions in 730 patients (96.7%), supratentorial lesions in 11(1.4%) and cervical lesion in 14 (1.9%). VAE was detected in 95 in series (12.5%) by Doppler /TEE, by a decrease of PtCO² in 38 (5%) and by drop in systolic Blood pressure in 30 (4%). VAE was detected in 29 (4%) patients during craniotomy before opening the dura, in 58 patients (61%) after opening the dura, and in 8 patients (8.42%) after closing the dura. There was no statistically significant difference in the incidence in VAE between lateral suboccipital craniotomy (70/582; 12%) and medial suboccipital craniotomy (25/148; 16.9%) (P= 0.13). Four patients had postoperative a neurological deficit related to VAE which resulted in severe morbidity two. There was no motility.

Conclusion: In our series, the VAE overall was rather rare and in general, a treatable complication. TEE represents the most sensitive method for the detection of air embolism. Our results suggest that the semi siting position is relatively safe and that the overall advantages overweight the associated risks.