The correlation between the preoperative measurement of estimated cerebral perfusion pressure and estimated intracranial pressure as obtained by trans cranial doppler with modified fisher grade as seen in computed tomography scan head in patients with acute sub arachnoid hemorrahage undergoing surgical clipping

Abstract

Background: In Aneurysmal Sub Arachnoid haemorrhage, precise Cerebral Perfusion Pressure (CPP) and Intracranial Pressure (ICP) measurement can only be achieved by an invasive monitoring device. The study aimed at non-invasively estimating the preoperative values of CPP and ICP by use of validated formulae. These estimated flow velocities (estimated CPP or eCPP and estimated ICP or eICP) of the Middle Cerebral Artery were obtained by Trans Cranial Doppler ultrasound and comparing it with the preoperative CT Head Fisher Scale. In the Institute Rimed Digi-Lite Trans Cranial Doppler machine was used for research and Siemens (Somatom) 64 CT Scanner from GE (Signa) was used to perform CT scan of patients.Methods: It is a prospective, observational study which was studied between July 2017 and December 2018 in Post Graduate Institute of Medical Education and Research, Chandigarh, India. This study is a secondary analysis of a prospective observational study which was primarily designed to evaluate the neurological outcome related to the effect of estimated Intracranial Pressure and estimated Cerebral Perfusion Pressure as measured by Trans Cranial Doppler in patients with a SAH. A total of 100 patients were recruited in this study.Results: There was significant correlation between estimated CPP and Fisher Grading. There was no strong correlation between the modified Fisher Grade and estimated ICP.Conclusions: This study was able to give a statistically significant correlation between eCPP and Fisher Grading (p value- 0.047), as the Modified Fisher grading increased, so did the eCPP, this observation was unique, and it went against the hypothesis. However, no statistically significant co-relation was seen during comparison of eICP and Fisher Grading (p value- 0.069).