Lakshmegowda Manjunatha, Muthuchellapan Radhakrishnan, Sharma Megha, Ganne S Umamaheswara Rao, Chakrabarti Dhritiman, Muthukalai Sindhupriya
Department of Anesthetics, United Lincolnshire Hospitals NHS Trust, Lincoln, United Kingdom.
Department of Neuroanesthesia and Neurocritical Care, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru, Karnataka, India.
Indian J Crit Care Med. 2023 Apr;27(4):254-259. doi: 10.5005/jp-journals-10071-24435.
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.
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.
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 ( 0.001). Cardiac output changes following norepinephrine infusion were not significant ( 0.113).
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.
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.
血管升压药用于蛛网膜下腔出血（SAH）患者以升高血压，旨在逆转缺血过程。本研究旨在评估在自发性动脉瘤性SAH术后患者中，使用去甲肾上腺素在不同药理学增强血压水平下全身和脑血流动力学的变化，包括脑血流自动调节。
本前瞻性观察性研究在接受手术夹闭且需要输注去甲肾上腺素的前循环动脉瘤破裂患者中进行。术后，当主治医生决定开始使用血管升压药时，以0.05μg/kg/min的速度开始输注去甲肾上腺素。输注速率每5分钟增加0.05μg/kg/min，以使收缩压（SBP）升高20%，然后升高40%。当血压在每个水平稳定5分钟时，记录大脑中动脉（MCA）的血流动力学和经颅多普勒（TCD）参数。
在自动调节受损的半球中，MCA的收缩期峰值、舒张期末期和平均流速随目标血压升高而增加，而在自动调节完整的半球中则没有增加。自动调节完整和不完整的半球之间TCD流速变化的相互作用具有显著性（P<0.001）。输注去甲肾上腺素后心输出量变化不显著（P>0.113）。
仅在自动调节受损时，去甲肾上腺素进行的高血压治疗才会增加脑血流速度，这一效应在SAH后局灶性脑缺血患者中是理想的。
Lakshmegowda M, Muthuchellapan R, Sharma M, Ganne SUR, Chakrabarti D, Muthukalai S. 药理学诱导的血压调控对动脉瘤性蛛网膜下腔出血患者心输出量和脑血流速度的影响。《印度重症监护医学杂志》2023；27(4):254 - 259。
