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Shadi Al-Afif, Hesham Elkayekh, Mazin Omer, Hans E. Heissler, Dirk Scheinichen, Thomas Palmaers, Makoto Nakamura, Elvis J. Hermann, Madjid Samii, and Joachim K. Krauss


Routine use of the semisitting position, which offers several advantages, remains a matter of debate. Venous air embolism (VAE) is a potentially serious complication associated with the semisitting position. In this study, the authors aimed to investigate the safety of the semisitting position by analyzing data over a 20-year period.


The incidence of VAE and its perioperative management were analyzed retrospectively in a consecutive series of 740 patients who underwent surgery between 1996 and 2016. The occurrence of VAE was defined by detection of bubbles on transthoracic Doppler echocardiography (TTDE) or transesophageal echocardiography (TEE) studies, a decrease of end-tidal CO2 (ETCO2) by 4 mm Hg or more, and/or an unexplained drop in systolic arterial blood pressure (≥ 10 mm Hg). From 1996 until 2013 TTDE was used, and from 2013 on TEE was used. The possible risk factors for VAE and its impact on surgical performance were analyzed.


There were 404 women and 336 men with a mean age at surgery of 49 years (range 1–87 years). Surgery was performed for infratentorial lesions in 709 patients (95.8%), supratentorial lesions in 17 (2.3%), and cervical lesions in 14 (1.9%). The most frequent pathology was vestibular schwannoma. TEE had a higher sensitivity than TTDE. While TEE detected VAE in 40.5% of patients, TTDE had a detection rate of 11.8%. Overall, VAE was detected in 119 patients (16.1%) intraoperatively. In all of these patients, VAE was apparent on TTDE or TEE. Of those, 23 patients also had a decrease of ETCO2, 18 had a drop in blood pressure, and 23 had combined decreases in ETCO2 and blood pressure. VAE was detected in 24% of patients during craniotomy before opening the dura mater, in 67% during tumor resection, and in 9% during wound closure. No risk factors were identified for the occurrence of VAE. Two patients had serious complications due to VAE. Surgical performance in vestibular schwannoma surgery was not affected by the presence of VAE.


This study shows that the semisitting position is overall safe and that VAE can be managed effectively. Persistent morbidity is very rare. The authors suggest that the semisitting position should continue to have a place in the standard armamentarium of neurological surgery.

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Jörn Heine, Dirk Scheinichen, Karsten Jaeger, Andreas Emmendoerffer, and Martin Leuwer

Administration of high-dose barbiturates may be used as an appropriate adjunctive treatment for control of intracranial pressure. The thiobarbiturate, thiopentone, has been reported to increase the rate of nosocomial pulmonary infection. This may be a substance-related effect of thiobarbiturates and it may be clinically important in barbiturate-sedated patients with severe head injury. Thus, the effects of the dose-response relationship of two commonly used barbiturates (thiopentone and methohexitone) on two vital aspects of neutrophil function were tested. We studied the production of superoxide anion during the respiratory burst by means of a flow cytometric method, and we assessed N-formyl-methionyleucylphenylalanine-induced neutrophil chemotaxis using the results produced by specific migration. The concentrations of thiopentone and methohexitone tested in vitro were adjusted to conform to the plasma concentrations reported for anesthesia and also to 10-fold higher concentrations. Only thiopentone dose dependently decreased respiratory burst and N-formyl-methionyleucylphenylalanine-induced chemotaxis. Methohexitone produced minimal effects in both concentrations. It was demonstrated that thiopentone had a direct effect on the intracellular respiratory burst oxidase enzyme system. The postulated free radical scavenging capacity of thiopentone was ruled out.