Assessment of hemodynamic and cerebrovascular changes after administration of mannitol in postoperative neursurgical patients: A combined transthoracic echo and transcranial Doppler study

Introduction: Mannitol is commonly used in neurosurgical units to reduce intracranial pressure. It has effects on both cardiovascular and cerebral hemodynamics. The temporal sequence of cardiovascular and cerebrovascular effects of mannitol has not been studied. This study assesses the hemodynamic and cerebrovascular changes using combined transthoracic and transesophageal echo after administration of mannitol in postoperative neurosurgical patients. Methods: The study was approved by ethics committee. Adult patients who were admitted in neurosurgical ICUs for surgical removal of intracranial tumors were included in the study. TCD and TTE findings were recorded on day 1 and day 2 following administration of 0.5 g/kg of mannitol. Comparison was made between operated and non operated side. Appropriate statistical analysis was done to assess the effects of mannitol on cardiovascular and mean flow velocity in middle cerebral artery blood flow. Results: HR, MAP, SPO2 showed no change after mannitol use. Mean flow velocity increased in both operated and non operated side but more in non operated side. Pulsatality index decreased from baseline but was not statistically significant. Resistance index also did not decrease in both sides. The estimated CPP was significantly increased at 5 mins on operated side upto 15 mins post mannitol use. There was no significant change in mean flow velocity, pulsatality index and resistance index ICP on second day. The ECHO variables like left ventricular dimensions, stroke volume and cardiac output did not change significantly following mannitol infusion. Conclusion: Adminstration of 0.5 g/kg of mannitol in immediate postoperative period was associated with increase in the mean flow velocity without change in cardiovascular variables. However the cerebrovascular effects was not seen significant change from baseline on second postoperative day. Our result may have an impact on the management of these patients in the neurocritical care.