Continuous assessment of Cerebral oxygenation using Near Infrared Spectroscopy (NIRS) and Transcranial Doppler (TCD) in patients of subarachnoid haemorrhage after Neuroendovascular coiling: Prospective Observational study

Aneurysmal subarachnoid hemorrhage is a neurological emergency with high morbidity and fatality rates. The overall prognosis depends on the volume of initial bleed, rebleeding and degree of cerebral ischemia. Coiling is a minimally invasive procedure which seals the aneurysm and prevents further bleeding. In patients of Subarachnoid hemorrhage, the assessment of cerebral autoregulation aids in the prognosis as well as detection of vasospasm. Early post operative management of patients undergoing coiling includes maintaining hemodynamic stability, early detection of cerebral hypoperfusion and management of cardiopulmonary complications which has influence on reducing cerebral vasospasm and thus cerebral ischemia. Monitoring of cerebral blood flow and cerebral oxygenation is a vital component in multimodal intensive care in patients of Subarachnoid Hemorrhage. Clinico radiological parameters, Modified Hunt and Hess grading and Fisher grading have been used to grade Subarachnoid Hemorrhage severity. Different Modalities have been used for bedside monitoring of cerebral perfusion. The importance of Transcranial Doppler (TCD) in acute phase of a Subarachnoid Hemorrhage and its clinical impact on occurrence of vasospasm and  outcome has been studied previously. But its use has the disadvantage of being investigator dependent and impractical for long duration monitoring in postoperative period. Continuous measurement of cerebral oxygenation with Near Infrared Spectroscopy has come as a promising tool and has been widely studied in numerous cardiac and surgical procedures. NIRS enables continuous and noninvasive measurement of regional cerebral oxygenation saturation via absorption of near infrared light that can provide a surrogate marker of change in cerebral blood flow in the form of Tissue oxygenation Index. In contrast to TCD, NIRS sensors are very easy to apply [since the probes attach to forehead with self adhesive pads] hence suitable for long term monitoring. Use of NIRS in postoperative Neuroendovascular procedures (coiling) for continuous measurement of cerebral oxygenation for early detection of hypoperfusion is yet to be explored. The aim of our study is to assess whether NIRS can be used for continuous measurement of cerebral oxygenation in postoperative period in Subarachnoid Hemorrhage patients undergoing Coiling and to correlate it with the clinicoradiological findings.