Jugular Bulb Pressure in Surgery of Patients in Sitting Position

Background. The pressure in brain sinuses (BSP) is used to monitor the effectiveness of various methods of prevention and treatment of venous air embolism (VAE) during surgeries in patients in the sitting position. A simpler and more approachable way is to measure the pressure in the superior bulb of the jugular vein (JBP), which accurately reflects the BSP. The dependence of the frequency and severity of VAE in JBP, however, has not been investigated, and the data on the effect of various methods of prevention and treatment of VAE on JBP are either insufficient or contradictory. The study was aimed to determine the dynamics of the JBP when bringing the patient to a sitting position, its relation with the severity of the VAE and to assess the effect of right atrium pressure (RAP), positive end expiratory pressure (PEEP) and decreased minute pulmonary ventilation (MPV) on it.Material and methods. The prospective study included 66 people who underwent intracranial surgery in a sitting position. In addition to the standard monitoring under general anesthesia with artificial lung ventilation, the superior bulb of the jugular vein and the right atrium were catheterized, and the esophagus was intubated with transesophageal echocardiography sensor. JBP was measured in a supine and sitting position and examined in relationship to RAP. In patients with JBP<0 mm Hg, its dynamics was evaluated at PEEP<0 cm H20 and MPV with end-tidal carbon dioxide (etCO2)=44 mm Hg, PEEP=15 cm H20 and MPV with etCO2=36 mm Hg. The Tuebingen scale (Tuebingen VAE) was used to determine the severity of VAE.Results. After bringing the patient to the sitting position the JBP significantly (W=2137.5; p<0.001) decreased by an average of 8 mm Hg, while in 11 (16.7%; 95% CI: 8.6-27, 8) cases it remained positive. No correlation was found between the RAP and JBP in the supine position (Z =-0.08225; p=0.9344) and in the sitting position (Z=1.2272, p=0.2198). The VAE frequency was 51% (95% CI 38.8-64). In patients with JBP <0 mm Hg, the frequency and severity of VAE was significantly higher than with JBP≥1 mm Hg (chi-square=4.37; df=1; p=0.036 and Z=2.47, p=0.015, respectively). Significant changes of JBP when PEEP 15 cm H2O and MPV with etCO2=36 mm Hg were not found (Z = -0.9784, p=0.3964 and Z=-1.3324, p=0.2305 respectively).Conclusion. 1. The negative JBP after bringing the patient to the sitting position is accompanied by an increase in the frequency and severity of VAE. 2. In patients in a sitting position, the correlation between RAP and JBP was not found. 3. Isolated PEEP and changes in ventilation do not lead to an increase in JBP