Variations in cerebral haemodynamics during irrigation phase in neuroendoscopic procedures

Not many centres measure intracranial pressure during an endoscopic procedure. However, if the irrigation fluid during endoscopy is not simultaneously drained, then some rise in intracranial pressure can be anticipated. This study was carried out to measure and monitor changes in intracranial pressure during the irrigation phase in a neuroendoscopic procedure using a Codman catheter placed in the parenchyma. Intracranial pressure was monitored in 13 patients undergoing surgical neuroendoscopic procedures under a standardised anaesthetic technique. Heart rate, mean arterial pressure, intracranial pressure and cerebral perfusion pressure were recorded at baseline and during the irrigation phase of the procedure. The heart rate during irrigation was comparable to baseline values, but the mean arterial pressure at the time of irrigation increased an average of 7 mmHg (P = 0.02). At the same time there was an average 34 mmHg increase in intracranial pressure (P < 0.001), producing an average 26 mmHg decrease in the cerebral perfusion pressure (P < 0.001) during irrigation. There was an average of four episodes of raised intracranial pressure (>25 mmHg) during the irrigation phase per patient. We suggest that the intracranial pressure be routinely monitored during neuroendoscopic procedures. Only then can the potential adverse effect of irrigation on intracranial pressure and cerebral perfusion pressure be assessed.