RT Journal A1 Shenkin HN, Goldfedder P T1 AIr embolism from exposure of posterior cranial fossa in prone position JF JAMA JO JAMA YR 1969 FD October 27 VO 210 IS 4 SP 726 OP 726 DO 10.1001/jama.1969.03160300066022 UL http://dx.doi.org/10.1001/jama.1969.03160300066022 AB To the Editor:—  Air embolism as a complication of exploration of the posterior fossa or cervical portion of the spine is usually associated with these procedures when carried out with the patient in the upright position. Michenfelder et al reported 39 instances of air embolism in 751 patients operated upon for lesions in the posterior cranial fossa.1The case reported below points out that precautions against air embolism are indicated even if the patient is in the prone position, especially in view of the recent widespread adoption of hyperventilation using a negative pressure phase in the respiratory cycle. Should the structures involved at operation include large venous channels, the possibilities for air embolism are obviously enhanced.Report of a Case:—  A 47-year-old right-handed man was admitted to the neurosurgical service at the Episcopal Hospital in Philadelphia on March 30, 1968, with a six-week history of vertigo and syncopal episodes,