Nosocomial Infections in Nonsurgical Patients Undergoing Extracorporeal Membrane Oxygenation: A Retrospective Analysis in a Chinese Hospital

Background: The effect of nosocomial infections (NIs) in adult patients undergoing ECMO has been rarely reported in China. Moreover, the effect of NIs on ECMO patients' mortality is still unclear and inconclusive according to literature data. In this study, we examined the prevalence, risk factors, causative organisms, and effects on outcomes of NIs in ECMO patients.

Methods: A total of 79 nonsurgical patients (mean age 53.3±15.2 year (yr); 66% male) who underwent ECMO between January 2011 and September 2020 were enrolled in this retrospective study. Patients' demographic and clinical data and ECMO parameters were collected from all patients.

Results: Among 79 patients who underwent ECMO for a total of 1253 ECMO days (mean time 15.9±14.1 d), 42 developed NIs. We observed 30 ventilator-associated pneumonia (VAP), 19 bloodstream infections (BSIs), and 4 urinary tract infections, corresponding to 23.9/1000 ECMO days, 15.2/1000 ECMO days, and 3.2/1000 ECMO days, respectively. ECMO duration (22.0±16.5 VS 8.9±5.3 d, P < 0.001), invasive mechanical ventilation (IMV) duration (27.4±20.5 VS 11.4±10.1 d, P < 0001), and ICU length of stay (35.9±22.9 VS 15.7±9.2 d, P < 0.001) were longer in patients with NIs. The independent risk factors for NIs were ECMO duration (Odds Ratio [OR], 1.414; 95% Confidence Interval [CI], (1.051-1.238); P = 0.002) and viral pneumonia (OR, 5.788; 95% CI, (1.551-21.596); P = 0.009). Gram-negative bacteria were the most common causative organisms of NIs; ), and were the most common bacteria. BSI (OR, 8.106; 95% CI, (1.384-47.474); P = 0.02) was an independent predictor for mortality.

Conclusion: NIs are common complications in patients during ECMO treatment, especially VAP, followed by BSI. Also, BSI can negatively affect the survival rate.