Episodic high irrigation pressure during surgical neuroendoscopy may causeintermittent intracranial circulatory insufficiency

Intermittent high peak pressure values inside the endoscope during neuroend oscopic surgical procedures are associated with postoperative morbidity. Un expected delay in awakening is the complication most frequently observed by the anesthesiologist as a result of high peak pressure values inside the e ndoscope. During eight neuroendoscopic procedures the authors continuously monitored cerebral hemodynamic function, using a transcranial doppler (TCD) probe fixed on patients' temporal window. We observed that episodes of hig h peak pressure values inside the endoscope during neuroendoscopic navigati on rinsing periods resulted in changes in the TCD wave profile consistent w ith "near intracranial circulatory arrestlike" wave. No systemic hemodynami c warning signs accompanied these intermittent episodes of severe decrease in cerebral perfusion pressure. When the rinsing liquid was allowed to esca pe, the pressure inside the endoscope decreased and the TCD wave immediatel y returned to its previous value. Neuroendoscopic procedures, although clas sified as minimally invasive surgery, warrant special monitoring that could alert us to a decrease in cerebral perfusion pressure. Middle cerebral art ery TCD recording is a reliable and accurate tool for this purpose.