Preoperative Dehydration does not Increase the Risk of Complications Following Elective Lumbar Surgery.

STUDY DESIGN: A retrospective cohort study. OBJECTIVE: The aim of this study was to evaluate the effect of preoperative dehydration on hospital length of stay (LOS), rates of 30-day postoperative complications, related reoperations, and readmissions. SUMMARY OF BACKGROUND DATA: Preoperative dehydration has long been associated with postoperative infection, deep vein thrombosis (DVT), acute renal failure, and an increased hospital LOS. To our knowledge, the effect of preoperative dehydration on complication rates for patients undergoing elective lumbar spine surgery has not been well described. METHODS: An analysis of American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) data from 2006 to 2013 was performed. Patients undergoing elective lumbar procedures were identified and exclusion criteria eliminated patients who underwent any emergency procedures, infections, tumor cases, or revision surgeries. Patient dehydration was defined as preoperative blood urea nitrogen/creatinine (BUN/Cr) ratio greater than 20. RESULTS: Patients (4698; 34.5%) with preoperative dehydration based on BUN/Cr ratio were identified. Univariate analysis was suggestive of an association between preoperative dehydration and an increased risk of DVT (1.1% compared with 0.6%; P = 0.002), urinary tract infection (2.5% compared with 1.6%; P < 0.001), and need for transfusion postoperatively (17.6% compared with 14.4%; P < 0.001). However, on the basis of multivariate regression, no significant association between dehydration and increased odds of aforementioned outcomes was identified. CONCLUSION: Preoperative dehydration does not appear to negatively affect perioperative outcomes or readmission in patients undergoing elective lumbar spine surgery. LEVEL OF EVIDENCE: 3.