Sitting position for neurosurgery: experience with preoperative contrast echocardiography in 301 patients.
A persisting foramen ovale (PFO) is the most common cause of paradoxical air embolism. To detect right-to-left shunting, transthoracic contrast echocardiography was performed preoperatively in 301 patients scheduled for neurosurgical procedures in the sitting position. Echocardiography yielded evaluable results in 285 patients (94.7%). In 72 of 285 patients (25.2%), a PFO was diagnosed on the basis of contrast echo signals appearing in the left atrium or ventricle within 5 heart cycles after application of contrast medium via a peripheral vein. If echo signals appeared in the left heart after more than 5 heart cycles, an intrapulmonary right-to-left shunt was considered (11 patients, 3.9%). Venous air embolism (VAE) occurred in 27.4% of 226 patients operated on in the sitting position and in none of the 59 patients operated on in a nonsitting position. We conclude that the sitting position during neurosurgery should be avoided in patients with preoperative evidence of a right-to-left shunt at contrast echocardiography to reduce the risk of paradoxical air embolism (PAE).
Department of Anesthesiology, University of Graz, Austria.
G
G
Schwarz
G
G
Fuchs
W
W
Weihs
H
H
Tritthart
H V
HV
Schalk
F
F
Kaltenböck
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D004452:Echocardiography; D004618:Embolism, Air / Q000209:etiology*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009493:Neurosurgery; D011187:Posture; D011300:Preoperative Care; D014680:Veins