Postoperative pneumonia after craniotomy: incidence, risk factors and prediction with a nomogram

Background: Postoperative pneumonia is the third most common complication in surgical patients. However, little is known regarding pneumonia after craniotomy, which is the most common surgical procedure in neurosurgery. Aim: To investigate the incidence of pneumonia and its association with the length of hospital stay, identify risk factors, and build a nomogram as a prediction model. Methods: The study population was based on the American College of Surgeons' National Surgical Quality Improvement Program database from 2005 to 2017. Both multi-variate logistic regression models and linear regression models were employed. Findings: The overall incidence rate of postoperative pneumonia was 3.11% in a total of 57,201 surgical procedures. Risk factors were age >55 years, male gender, low body mass index (BMI), diabetes, functional dependence, ventilator dependence, history of severe chronic obstructive pulmonary disease, hypertension, systemic sepsis, white blood cell count >12,000, emergency case, American Society of Anesthesiologists class >= 3, general anaesthesia and total surgical time >240 min. Ten featured factors were used in the nomogram (C-statistic=0.803). Postoperative pneumonia was associated with extended hospital stay. Compared with other postoperative complications, pneumonia had the second-highest impact on the extension of hospital stay (by 4.7 days). Conclusion: This study identified several pre-operative risk factors for postoperative pneumonia after craniotomy. Novel factors including male gender and low BMI warrant further investigation. This novel nomogram could serve as a reliable tool to evaluate the risk of postoperative pneumonia pre-operatively. (C) 2020 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.