To the Editor
In the Summer 1990 issue, Dr. Lee Balaklaw raises the question of the optimal positioning of a central venous catheter for the aspiration of air embolism during neurosurgery in the sitting position. In 1981, Bunegin et. al. (1,2) following experiments with a silastic rubber atrium model, suggested that the best recovery of air was obtained with the catheter tip in the vena cava, not the heart. They recommended the use of a multiple-orifice catheter with the tip located 2 cm below the junction of the superior vena cava and the atrial cavity. If a single (terminal) orifice catheter was used, the best position of the tip was 3 cm above the junction. In either case the catheter did not enter the atrium.
As far as I know, this work has not been confirmed in human subject, nor has it been refuted. It is our practice to insert the catheter via the antecubital vein under fluoroscopic control. A method has also been described of using the saline-filled catheter as one lead of an ECG and observing a bipolarity followed by inversion of the P wave as the catheter is advanced 3, but this method could involve significant micro-shock hazards.
Peter H. Byles, M.D. SUNY Health Science Center
Syracuse, New York
- Bunegin L, Albin MS, Helsel PE, Hoffman A and Hung TK: Positioning the right atrial catheter: A model for reappraisal. Anesthesiology 1981; 55:343-348.
- Mitchenfelder JD: Central venous catheter in the management of air embolism: whether as well as where (Editorial). Anesthesiology 1981; 55:339-341.
- Shapiro H, in: Monitoring in Anesthesia, Saidman LJ and Smith NT (Eds), Chapter 8. Boston: Butterworth, 1984.