Anaesthesia and the Valsalva manoeuvre. A test of circulatory responses in neurosurgical patients including those in the sitting position.

The four phases of the Valsalva manoeuvre were studied before and after anaesthesia had been induced with a technique of either spontaneous breathing or controlled ventilation of the lungs. The Valsalva manoeuvre was found to be an unreliable predictor of a patient's ability to tolerate the upright or sitting position for neurosurgical procedures. However, a false negative response is more likely to occur than a false positive response.