RESUMEN
Background: Vasopressors are used in patients with subarachnoid hemorrhage (SAH) to increase blood pressure with the idea of reversing the ischemic process. The current study is designed to evaluate the changes in systemic and cerebral hemodynamics, including cerebral blood flow autoregulation, at different pharmacologically augmented blood pressure levels using norepinephrine in patients with spontaneous aneurysmal SAH following surgery. Materials and methods: This prospective observational study was carried out in patients with ruptured anterior circulation aneurysms who underwent surgical clipping and required norepinephrine infusion. Postoperatively, when the treating physician decided to start a vasopressor, norepinephrine infusion was started at 0.05 µg/kg/min. The infusion rate was increased by 0.05 µg/kg/min every 5 minutes to achieve a 20% and then 40% increase in the systolic blood pressure (SBP). When the blood pressure stabilized at each level for 5 minutes, hemodynamic and transcranial doppler (TCD) parameters in the middle cerebral artery (MCA) were recorded. Results: Peak systolic, end-diastolic, and mean flow velocities in the MCA increased with targeted blood pressure increase in the hemispheres with impaired autoregulation and not in the hemispheres with intact autoregulation. The interaction of changes in TCD flow velocities between hemispheres with and without intact autoregulation was significant (p < 0.001). Cardiac output changes following norepinephrine infusion were not significant (p = 0.113). Conclusion: Hypertensive therapy with norepinephrine increases cerebral blood flow velocity only when autoregulation is impaired, an effect that is desirable in patients with focal cerebral ischemia following SAH. How to cite this article: Lakshmegowda M, Muthuchellapan R, Sharma M, Ganne SUR, Chakrabarti D, Muthukalai S. The Effect of Pharmacologically Induced Blood Pressure Manipulation on Cardiac Output and Cerebral Blood Flow Velocity in Patients with Aneurysmal Subarachnoid Hemorrhage. Indian J Crit Care Med 2023;27(4):254-259.
RESUMEN
Background and Aims: Analgesia Nociception Index (ANI) and Surgical Pleth Index (SPI) are measures of nociception-antinociception balance during general anaesthesia. The validity of these two monitors during autonomic changes brought about by intraoperative blood loss and noradrenaline infusion has not been studied earlier. The primary objective of the study was to determine the effect of bleeding on ANI and SPI. The secondary objective was to observe the effect of noradrenaline infusion on ANI and SPI and the correlation between ANI and SPI. Methods: In this prospective observational study, 43 patients undergoing surgery for excision of a meningioma or for traumatic brain injury were included. Heart rate, mean arterial pressure, ANI, SPI, response and state entropy were recorded every 5 min from anaesthetic induction till skin closure. ANI and SPI values before bleeding were compared with the values following bleeding. The effect of bleeding and noradrenaline on ANI and SPI were studied using linear mixed effect model. Results: Bleeding increased the values of ANI and the increase was higher in the presence of noradrenaline and it was statistically significant (P = 0.028 and 0.023). SPI was not affected by bleeding or with noradrenaline infusion. ANI and SPI had a poor negative correlation (r = - 0.01). Conclusion: Values of ANI increased significantly during episodes of intraoperative acute blood loss and with co-administration of noradrenaline. SPI seems to be more dependable when compared to ANI under such conditions.