Cerebral hemodynamic and metabolic changes caused by brain retraction after aneurysmal subarachnoid hemorrhage

Kent D. Yundt, Robert L. Grubb, Michael N. Diringer, William J. Powers

Research output: Contribution to journalArticlepeer-review

63 Scopus citations


OBJECTIVE: The cerebral hemodynamic and metabolic effects of aneurysmal subarachnoid hemorrhage are complex. To investigate the impact of surgical retraction, we analyzed positron emission tomography (PET) studies that measured the regional cerebral metabolic rate for oxygen, regional oxygen extraction fraction, and regional cerebral blood flow in four patients before and after right frontotemporal craniotomies for clipping of ruptured anterior circulation aneurysms. METHODS: Preoperative studies were conducted 1 day before surgery and postoperative studies 6 to 17 days after surgery. No patient had hydrocephalus or intracerebral hematoma. At the time of the second PET study, none of the patients had signs of clinical vasospasm. Regional measurements were obtained from the right ventrolateral frontal and anterior temporal regions corresponding to the area of retraction and compared to the same regions in the opposite hemisphere. To establish a quantitative means to differentiate between hemodynamic and metabolic changes related to arterial vasospasm and those caused by brain retraction, we studied a second group of preoperative patients, who had undergone PET during angiographic and clinical vasospasm. RESULTS: There was a 45% reduction in regional cerebral metabolic rate for oxygen (1.87 ± 0.22 to 1.04 ± 0.28 ml 100 g-1 min-1) and 32% reduction in regional oxygen extraction fraction (0.41 ± 0.04 to 0.28 ± 0.03) in the region of retraction but no change in the opposite hemisphere (paired t test; P = 0.042 and 0.003, respectively). There was no change in regional cerebral blood flow in any region. Brain retraction produced a focal area of tissue injury at the site of retractor blade placement, as compared to more diffuse vascular territory changes produced by vasospasm. CONCLUSION: This reduction in the cerebral metabolic rate of oxygen and the oxygen extraction fraction indicates a primary reduction in metabolism and uncoupling of flow and metabolism (luxury perfusion). Similar findings of luxury perfusion have been reported after ischemic stroke and traumatic brain injury. Further studies will be necessary to fully understand the clinical and pathophysiological significance of these observations.

Original languageEnglish
Pages (from-to)442-451
Number of pages10
Issue number3
StatePublished - Mar 1997


  • Brain retraction
  • Cerebral aneurysm
  • Cerebral blood flow
  • Subarachnoid hemorrhage
  • Vasospasm


Dive into the research topics of 'Cerebral hemodynamic and metabolic changes caused by brain retraction after aneurysmal subarachnoid hemorrhage'. Together they form a unique fingerprint.

Cite this