Elevated Lactate Dehydrogenase Level Predicts Postoperative Pneumonia in Patients with Aneurysmal Subarachnoid Hemorrhage.

Lactate dehydrogenase (LDH) is a nonspecific inflammatory biomarker and has been reported to be useful in predicting community-acquired pneumonia and Mycoplasma pneumoniae pneumonia. The connection between LDH level and postoperative pneumonia (POP) in patients with aneurysmal subarachnoid hemorrhage (aSAH) is still unclear. The aim of this study was to assess feasibility of predicting POP in patients with aSAH using LDH.Admission serum LDH level was obtained in 647 patients with aSAH enrolled in a prospective observational study. The relationship between LDH level and POP was analyzed.POP occurred in 187 patients (28.90%). Patients with POP had significantly higher LDH levels than patients without POP (261.26 ± 126.51 U/L vs. 189.00 ± 69.20 U/L, P < 0.001). Multivariate analysis showed that LDH level remained a significant independent factor associated with POP in patients with aSAH, even after adjusting for possible confounding factors. Receiver operating characteristic curve analysis showed that LDH level had a sensitivity of 63.6% and a specificity of 71.3% for predicting POP based on best threshold of 203.5 U/L. There were additive interactions between elevated LDH level and World Federation of Neurosurgical Societies grade or mechanical ventilator use. When patients were classified by World Federation of Neurosurgical Societies grade or mechanical ventilator use, regardless of World Federation of Neurosurgical Societies grade (<III or ≥III) or length of mechanical ventilator use (0-24 hours or ≥24 hours), the POP-free rate of patients with admission LDH ≥250 U/L was significantly worse compared with patients with LDH <250 U/L.LDH might be a helpful predictor of POP occurrence in patients with aSAH.