Cardiac arrhythmia induced by pneumoencephalography.

Cardiovascular collapse associated with pneumoencephalography (PNE) has been reported but there has been no prospective study of its nature and cause. We have recorded prospectively the e.c.g. of 82 unselected patients, with no cardiovascular or metabolic disease, undergoing PNE under general anaesthesia. The frequency of arrhythmia following air injection was 60%; bradycardia 22%; ventricular ectopic beats 26%; nodal rhythm or sinus tachycardia 11%. Cardiovascular collapse occurred in three patients; two with "torsades de pointes" and one with bigeminy and q.r.s. block. Arrhythmia was more frequent in patients with a pituitary tumour and intracranial hypertension (91%). Eight postoperative control PNE examinations were uneventful. Three of four patients with frontal lobe tumours and four of seven with posterior fossa tumours exhibited arrhythmia.