The Role of Elevated Lactate as a Risk Factor for Pulmonary Morbidity After Early Fixation of Femoral Shaft Fractures

OBJECTIVES:To evaluate lactate levels before reamed intramedullary nailing (IMN) of femur fractures treated with early fixation. DESIGN:Retrospective study. SETTING:Three academic, tertiary care trauma centers. PATIENTS:Age ≥18 years, injury severity score ≥17, admission lactate ≥ 2.5 mmol/L, elevated preoperative lactate = preoperative lactate ≥ 2.5 mmol/L. INTERVENTION:Reamed IMN of femur fracture within 24 hours. MAIN OUTCOME MEASURE:Total duration of mechanical ventilation, pulmonary complications (PC) = duration of mechanical ventilation ≥5 days. RESULTS:Four hundred and fourteen patients identified; 294/414 (71.0%) with admission lactate ≥ 2.5 mmol/L. No difference in PC among the groups (86/294, 29.3% vs. 28/120, 23.3%; P = 0.22). Median admission lactate3.7 (interquartile range3.0–4.6); median preoperative lactate2.8 (interquartile range1.9–3.5). 184/294 (62.6%) demonstrated an elevated preoperative lactate (≥ 2.5 mmol/L) before fracture fixation. No difference in elevated preoperative lactate and vent days (4.8 ± 9.9 vs. 3.9 ± 6.0, P = 0.41) or PC (50/86, 58.1% vs. 134/208, 64.4%; P = 0.31). There was no difference in PC when preoperative lactate was considered separately for a lactate ≥3.0 (34/123, 27.6% vs. 52/171, 30.4%; P = 0.61), ≥3.5 (21/79, 26.6% vs. 65/215, 30.2%; P = 0.54), or ≥4.0 (14/50, 28.0% vs. 72/244, 29.5%; P = 0.83). Multivariable linear regression modeling demonstrated that admission lactate [coefficient of variation0.84, standard error0.33, 95% confidence interval (CI)0.20–1.49] was correlated with duration of mechanical ventilation, after adjusting for emergency department Glasgow Coma Scale, age, chest Abbreviated Injury Scale (AIS) score, abdominal AIS, and admission glucose. Logistic regression demonstrated admission lactate was also significantly associated with PC (odds ratio1.26, 95% CI1.03–1.53) after controlling for age, admission Glasgow Coma Scale, chest AIS, abdominal AIS, admission pulse and admission glucose; preoperative lactate was not a risk factor (odds ratio0.84, 95% CI0.65–1.09) for PC. CONCLUSION:Median admission lactate of 3.7 mmol/L was associated with duration of mechanical ventilation ≥5 days, whereas median preoperative lactate of 2.8 mmol/L was not, when multisystem trauma patients with a femoral shaft fracture were treated with reamed IMN within 24 hours after admission. LEVEL OF EVIDENCE:Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.