Use of near infrared spectroscopy for the prediction of perioperative complications in patients undergoing elective microsurgical resection of cerebral arteriovenous malformations- a prospective observational trial (NIRSCAM trial)

Purpose Cerebral arteriovenous malformations (AVM) represent focal abnormal areas of low resistance circulation which render the peri-nidal neuronal tissue susceptible to ischemia. The post-excision cerebral perfusion surge can result in hyperaemic complications.We hypothesised that Near Infrared Spectroscopy (NIRS)-guided perioperative management can aid in the prediction and prevention of perioperative complications in patients presenting for surgical excision of cerebral AVMs. We also intended to identify a threshold value of regional cerebral oxygen saturation (rScO(2)) to predict the incidence of perioperative complications.Methods This was a prospective observational study involving patients undergoing elective supratentorial AVM resection surgeries. Intraoperative rScO(2) and hemodynamic monitoring were done and continued for postoperatively for 12 h. Any drift in rScO(2) by > 12% from baseline was managed as per study protocol and perioperative adverse events were recorded and analyzed. Post surgery,for analytical purpose patients were categorized into two groups, Group A - patients without complications and Group B - patients who had complications postoperatively.Results Twenty-five patients presenting for surgical excision of cerebral AVM were recruited for this study of which 9 patients had postoperative adverse events and were allocated to group B. The ipsilateral mean rScO(2) at the time of complication (Pc) was significantly lower in Group B than in group A [62.08 +/- 9.33 vs.70.52 +/- 7.17; p = 0.04]. The mean ipsilateral rScO(2) drift from N2- N5 (i.e., post excision) was significantly higher in Group B than in Group A [12.01 +/- 2.63% vs. 4.98 +/- 5.7%;p = 0.02]. Mean ipsilateral rScO(2) Drift ratio (N5 :N2) was significantly higher in group B as compared to group A [1.32 +/- 0.01 vs. 1.01 +/- 0.06;p < 0.001]. In the immediate post excision phase, the ipsilateral mean rScO(2) was significantly higher in Group B at the post excision time point compared to Group A [ 83.03 +/- 6.08 vs. 73.52 +/- 7.07;p < 0.01)]. The mean ipsilateral rScO(2) drift from N1-N6 (i.e., postoperatively) was significantly higher in Group B as compared to Group A [14.96 +/- 0.080% vs. 6.88 +/- 4.5% ; p < 0.01]. Similarly, the Mean Ipsilateral rScO(2) Drift ratio (N6:N1) was significantly lower in group B as compared to group A [2.17 +/- 0.02 vs. 1.05 +/- 0.03 ;p < 0.0001].Conclusions In patients undergoing cerebral AVM resection, a post-resection ipsilateral rScO2 increase by > 12% with a drift ratio of > 1.3 could signify cerebral hyperemia. A postoperative ipsilateral rScO2 drift > 14.5% with a drift ratio of 2.1 from the baseline is associated with postoperative complications in our study. Further multi-centric randomized control trials are needed to support our research findings.