Clinical presentation, aetiological characteristics, risk factors and in-hospital outcome of nosocomial infection following acute aortic dissection surgery in adult patients.

BACKGROUND: Nosocomial infection (NI) is one of the most common complications after acute aortic dissection surgery (AADS) and contributes significantly to mortality and length of hospital stay. Therefore, this study analysed the clinical characteristics of NI and determined the risk factors for the occurrence and development of NI and in-hospital outcomes.

METHODS: During this study, 429 adult patients with AADS were divided into an infected group (n = 141) and a noninfected group (n = 288). Complete clinical data (including baseline clinical characteristics and laboratory results, surgery-related variables, and clinical outcomes) were collected for statistical analysis. Multivariate logistic regression was used to determine the independent risk factors for the occurrence of NI after AADS.

RESULTS: The incidence of NI in AADS was 29.0%. The main clinical presentations were hospital-acquired pneumonia (HAP = 51.8%), ventilator-associated pneumonia (VAP = 24.8%) and bloodstream infection (BSI = 18.4%). The most common pathogenic bacteria were gram-negative bacilli (GNB = 68.8%), including Klebsiella pneumoniae (27.7%), Pseudomonas aeruginosa (16.3%) and Acinetobacter baumannii (13.5%). Multivariate regression analysis found that preexisting cerebrovascular disease, lower estimated glomerular filtration rate (eGFR), total protein and serum albumin, longer operation time and cardiopulmonary bypass (CPB) time, second operation in-hospital, exposure to extracorporeal membrane oxygenation (ECMO) and continuous renal replacement therapy (CRRT), and proton pump inhibitor (PPI) use were independent risk factors for the occurrence of NI (all P < 0.01). Compared with noninfected patients, the intensive care unit (ICU) stay time and total hospital stay time were significantly prolonged after the occurrence of NI (all P < 0.001). The risks of other complications, such as acute kidney injury (AKI), acute upper gastrointestinal haemorrhage, new cerebral infarction, paraplegia or hemiplegia, and new cerebral haemorrhage, were significantly higher in patients with NI after AADS than in noninfected patients (all P < 0.001). The in-hospital mortality (46.1%) of NI after AADS was significantly higher than that of noninfected patients (3.5%, P < 0.001).

CONCLUSIONS: This study identified the high morbidity and mortality of NI after AADS. The most common types of infection were HAP, VAP and BSI, and the pathogenic microorganisms were Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii. Total protein, serum albumin, eGFR, longer operation time and CPB time, second operation in-hospital, exposure to ECMO and CRRT, and PPI use were independent risk factors for the occurrence of NI.