The relationship between bi-frontal pneumocephalus and acute postoperative agitation following craniotomy

Objective To analyze the relationship between bi-frontal pneumocephalus (BFP) and acute postoperative agitation following craniotomy. Methods A total of 365 consecutive adult patients underwent elective craniotomy at Department of Critical Care Medicine, Beijing Tiantan Hospital, Capital Medical University from July 2016 to December 2016 and their clinical data were retrospectively analyzed in this study. Sedation-agitation scale (SAS) was used to evaluate the patients 24 hours after the enrollment. Agitation was defined as an SAS score equal to or above 5. Patients were divided into 2 groups according to the presence or absence of BFP in postoperative CT scans within 12 hours post operation: the BFP group (n=83)and non bi-frontal pneumocephalus (NBFP) group (n=282). PSM (propensity score matching) was conducted to reduce confounding bias between the groups. The intergroup analysis was conducted on acute postoperative agitation and other recovery parameters. Results Among 365 patients, 45 (12.3%) developed acute postoperative agitation and 83 (22.7%) developed BFP. With PSM, 83 pairs of patients were successfully matched. After matching, compared to NBFP group, the incidence of postoperative agitation was higher (24.1% vs. 3.6%, P<0.001), use of sedation was much more (14.5% vs. 2.4%, P=0.005) and hospital length of stay was longer (10 vs. 8 days, P<0.001). Conclusion Brain tumor patients following elective craniotomy with BFP are more likely to develop acute postoperative agitation. Key words: Neurosurgical procedures; Brain neoplasms; Propensity score; Intracranial surgery under general anaesthesia; Acute postoperative agitation; Bi-frontal pneumocephalus