Prevention of venous air embolism in paediatric neurosurgical procedures performed in the sitting position by combined use of MAST suit and PEEP

Abstract

We studied 60 children undergoing neurosurgical procedures in the sitting position. Routine monitoring included ECG, pulse oximetry, invasive arterial pressure, in particular mean arterial pressure (MAP), and right atrial pressure (RAP). Children were allocated to two groups. In group B lower body positive pressure and positive end-expiratory pressure (PEEP) were used for preventing venous air embolism (VAE). In this group, antishock trousers (MAST suit) were adjusted in supine children. After induction of anaesthesia, different positions were studied: supine and sitting before MAST suit inflation, sitting with MAST suit inflated up to a pressure of 40 mmHg in the lower compartments and 30 mmHg in the abdominal compartment, and finally a combination of lower body positive pressure and PEEP of 8-10 cm H2O. In group A no MAST suit or PEEP was used. Continuous monitoring of end-tidal carbon dioxide pressure throughout (PE'CO2) was used to detect VAE. In order to evaluate the transmission of pressures from the right atrium to the veins at the base of the skull, jugular bulb venous pressure (JBVP) was measured in 20 patients by retrograde catheterization. The incidence of VAE was compared in the two groups. On placing children into the sitting position, a significant decrease in RAP and JBVP was noted without significant changes in MAP in the two groups. Inflation of the MAST suit induced a dramatic increase in RAP and JBVP, reinforced by addition of PEEP. There was a strong positive relationship between RAP and JBVP. There were no deleterious side effects or differences between the two groups in peroperative blood product requirements or surgical general conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of Positioning on Cerebral Oxygenation

“…Sequential compression of lower limbs significantly reduces hypotension and can support the mean arterial pressure (MAP) and the stroke volume index [33]. Inflation of medical anti-shock trousers (MAST) is a strategy used to increase CVP and jugular venous bulb pressure to reduce the risk of venous air embolism [34]. Anesthetic induction dose, volatile agents and intermittent positive pressure ventilation (IPPV) all aggravate this effect on preload [32].…”

A Standardized Protocol for the Prevention of Clinically Relevant Venous Air Embolism During Neurosurgical Interventions in the Semisitting Position

“…However, there was an increasing number of observations of major complications associated with the semisitting position, including fatal cases mainly attributable to venous air embolism (VAE), paradoxical air embolism (PAE), tension pneumocephalus, spinal cord damage with paraplegia, compressive peripheral neuropathy, and cardiac arrest (2, 3, 7, 12, 14, 16, 20, 23a, 24, 26-30). Especially, the incidence of VAE was found to be as high as 50% (3,14,30). Consequently, neuroanesthesiologists and neurosurgeons became increasingly reluctant to use the semisitting position.…”

Paradoxical air embolism resulted in acute myocardial infarction and massive ischemic brain injury in a patient operated on in a sitting position

“…Это не единственная пу-бликация, где за счет подъема нижних конечно-стей, форсированной инфузионной терапии кол-лоидными растворами и других хитростей авторы пытаются избежать отрицательного внутрисинус-ного давления [30]. В одной из таких работ вообще предлагалось надевать на больных специальные пневмокомпрессионные штаны («military anti shock trousers»), которые при инфляции выдавли-вают депонированную кровь из сосудов нижних конечностей [31]. Беда всех этих профилактиче-ских подходов в том, что все они весьма ограни-ченно эффективны и их профилактический эф-фект в серьезных исследованиях не подтвержден [1,2].…”