Neutrophil-lymphocyte ratio on first and third postoperative days: associated with severe pneumonia in aneurysmal subarachnoid hemorrhage patients undergoing surgeries.

Severe postoperative pneumonia can increase the risk of poor outcomes in patients with aneurysmal subarachnoid hemorrhage (aSAH). We aimed to explore the associations of preoperative or postoperative inflammatory markers calculated from blood cell counts with severe pneumonia. This retrospective study was conducted at the First Affiliated Hospital of Yangtze University from January 2019 to June 2023. The associations of neutrophil-lymphocyte ratio (NLR), monocyte-lymphocyte ratio (MLR), platelet-lymphocyte ratio (PLR), systemic immune inflammation index (SII), and systemic inflammation response index (SIRI) with severe pneumonia were analyzed. There were 159 patients with pneumonia and 21 patients without pneumonia. There were 41 patients with severe pneumonia and 118 patients with non-severe pneumonia. The multivariate logistic regression analysis showed that NLR on the first postoperative (OR = 2.574, 95%CI: 1.035-6.403, p = 0.042) and third postoperative days (OR = 4.296, 95%CI: 1.699-10.860, p = 0.002) were associated with severe pneumonia in aSAH patients. Among patients ≥ 60 years, SIRI on the preoperative day (OR = 7.430, 95%CI: 1.443-38.251, p = 0.016) and NLR on the third postoperative day (OR = 4.748, 95%CI: 1.286-17.801, p = 0.020) were associated with severe pneumonia. Among patients < 60 years, NLR on the first postoperative day (OR = 24.149, 95%CI: 3.476-167.747, p = 0.001) was associated with severe pneumonia. The NLR on the first and third postoperative days were possibly associated with severe pneumonia in aneurysmal subarachnoid hemorrhage patients undergoing clipping or embolization surgeries. Dynamic detection of NLR during early perioperative period may help clinicians to predict the development of severe pneumonia.