Utility of monitoring cerebral autoregulation after subarachnoid hemorrhage. Results from a prospective observational study

Authors: Budohoski KP, Czosnyka M, Smielewski P, Kasprowicz M, Helmy A, Bulters D, Zabek M, Pickard JD, Kirkpatrick PJ.

INTRODUCTION:

Delayed cerebral ischemia (DCI) is a major contributor to morbidity and mortality after subarachnoid hemorrhage (SAH). Data challenge vasospasm as the sole cause of ischemia and suggest other factors, such as dysfunctional cerebral autoregulation. We tested the hypothesis that early autoregulatory failure, detected using near-infrared spectroscopy, TOxa index, and transcranial Doppler based, Sxa index, can predict DCI. We analyzed the relationship between indices and the transient hyperemic response test (THRT) which uses a blood pressure stimulus.

METHODS:

In this prospective observational study we enrolled consecutive patients within <5 days of onset from aneurysmal SAH. The primary end-point was occurrence of DCI at 21 days post-ictus. The predictive value of autoregulatory disturbances in the first 5 days was assessed using Cox proportional hazards and multivariate models. The benefit of using multiple indices was analyzed.

RESULTS:

98 patients were included. Cox analysis demonstrated increased odds of DCI with early autoregulation failure (Odds Ratio (OR): 7.46, 95%CI: 3.03-18.40 and OR: 4.52, 95%CI: 1.84-11.07 for Sxa and TOxa respectively) but not vasospasm (OR: 1.36, 95%CI: 0.56-3.33). Sxa and TOxa remained independent predictors of DCI in multivariate analysis (OR: 12.66, 95%CI: 2.97-54.07 and OR: 5.34, 95%CI: 1.25-22.84 for Sxa and TOxa respectively). Sxa and TOxa showed good accuracy in predicting impaired autoregulation evidenced by a negative THRT (area under the curve (AUC): 0.788, 95% CI: 0.723 to 0.854 and AUC: 0.827, 95% CI: 0.769 to 0.885, respectively). 100% specificity was seen for combined monitoring, with 13/13 patients with impaired autoregulation in all 3 methods developing DCI.

CONCLUSION:

Disturbed autoregulation in the first 5 days post-SAH predicts DCI. Although colinearities exist between the assessed methods, multimodal monitoring of cerebral autoregulation can aid in predicting DCI.

Full text and source: Pubmed

Neurosurgery. 2013 Aug;60 Suppl 1:182-3. doi: 10.1227/01.neu.0000432779.66471.ca.

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