The Impact of Dehydration on Surgical Outcomes in Decompression Craniectomy for Traumatic Brain Injury: A Large Propensity-Matched Retrospective Cohort Study

Introduction: To date, no study has investigated the connection between dehydration and surgical outcomes in patients undergoing craniectomy for traumatic brain injuries (TBI). The purpose of this study is to explore this potential association. The study defines dehydration as BUN/creatinine between 20.10-65.00 units or osmolarity of serum or plasma between 295.01-420.00 mosm/kg one day preoperatively.

Methods: Using the TriNetX database, we conducted a retrospecitve analysis from 60 US healthcare organizations over the last 20 years. Inclusion crtieria were adults(18-90 years old) diagnosed with TBI who recieved subsequent decompressive craniectomy with preoperative BUN/Creatinine or serum or plasma osmolarity. 6,516 patients were identified. 3,386 patients met the study definition of dehydration. Cohorts were propensity-matched by demographics, yielding 3130 patients per cohort. T-tests were utilized to compare surgical outcomes at four postoperative timepoints: 1 day, 30 days, 90 days, and 30-90 days.

Results: At postoperative day 1, dehydrated patients exhibited higher incidences of emergency intubation(17.9% vs. 14.1%, p=0.001), acute kidney injury(7.5% vs. 4.4%, p=0.001), acute pulmonary failure(50.2% vs. 33.7%, p=0.001), and dysphagia with abnormal swallow study(9.2% vs. 7.2%, p=0.006). Dehydrated patients were more likely to experience ventilator use, ventilator associated complications, and pneumonia at all timepoints(p <.05). At postoperative days 1, 30, and 90, dehydrated patients had higher incidences of mortality and nontraumatic hemorrhage(p <.05). Interestingly, there was a decrease in ED visits for dehydrated patients at 30 days(5.8% vs. 8.1%, p=0.001) and 90 days(13.7% vs. 16.6%, p=0.001) which may be explained by increased mortality at 30 days(29.1% vs. 20.7%, p=0.001) and 90 days(32.3% vs. 23.7%, p=0.001).

Conclusion : Dehydrated patients who receive craniectomy for TBI are at an increased risk for postoperative emergency re-intubation, acute kidney injury and pulmonary failure, ventilator use with complications, pneumonia, mortality, and nontraumatic hemorrhage. These retrospective findings demonstrate the potential benefit of perioperative hydration, which require further retrospective studies and potentially prospective clinical studies.