O-196 - FROM BASIC RESEARCH TO CLINICAL PRACTICE: THE IMPACT OF A LAMINAR AIRFLOW HEPA FILTER ON SURGICAL SITE INFECTION IN VASCULAR SURGERY

TOPIC:
Vascular Infection
AUTHORS:
González-Sagredo A. (Hospital Universitari de Bellvitge ~ Hospitalet de Llobregat ~ Spain) , Iborra E. (Hospital Universitari de Bellvitge ~ Hospitalet de Llobregat ~ Spain) , Cedeño Peralta R.J. (Hospital Universitari de Bellvitge ~ Hospitalet de Llobregat ~ Spain) , Granados Suarez S.J. (Hospital Universitari de Bellvitge ~ Hospitalet de Llobregat ~ Spain) , Huici-Sanchez M. (Hospital Universitari de Bellvitge ~ Hospitalet de Llobregat ~ Spain) , Palacios Maldonado S. (Hospital Universitari de Bellvitge ~ Hospitalet de Llobregat ~ Spain) , Espinar Garcia E. (Hospital Universitari de Bellvitge ~ Hospitalet de Llobregat ~ Spain) , Vila Coll R. (Hospital Universitari de Bellvitge ~ Hospitalet de Llobregat ~ Spain)
Introduction:
Surgical site infections (SSI) are among the most common and fearsome complications in vascular surgery, given its high morbidity and mortality rates[1]. One factor that might be related to the SSI incidence is the type of airflow filter used in the operating room. The most commonly used airflow filter systems are the turbulent airflow filter (Figure 1A) and the laminar airflow HEPA filter (Figure 1B)[2]. The latter has been reported to promote a greater reduction in the environmental microbiological load in the operating room (80,97% vs. 99,97%)[3]. Therefore, we conducted an observational study with the primary objective of assessing whether this reduction in airborne particles associates with a reduction in SSI incidence. Also, as a secondary objective, we intended to study the predictive factors of SSI in vascular surgery.
Methods:
This is a single-center, retrospective cohort study. SSI incidence has been estimated for femoral approach arterial surgeries. Observation periods were July 15th, 2018—July 15th, 2019 (turbulent airflow filter cohort), and July 15th, 2020—July 15th, 2021 (laminar airflow HEPA filter [Camfil Megalam MD14 Prosafe®] cohort). Surgical emergencies and reinterventions were excluded. SSIs were defined according to the National Healthcare Safety Network criteria. The cumulative incidence of surgical site infections has been estimated for both cohorts, and its 95% confidence interval (95%CI) has been calculated. A propensity score analysis has been used to compare SSI incidence in both cohorts minimizing selection and confounding biases. Outcome measures assessed as potential SSI predictors were age, gender, smoking load, hypertension, diabetes, dyslipidemia, heart disease, chronic renal failure, pneumopathy, stroke, serum albumin, and body mass index. Statistical analyses were performed with R version 4.1.0.
Results:
A total of 200 patients were enrolled, of whom 78 were in the turbulent airflow cohort (66 men, mean age [SD] 72 [±11] years old) and 122 were in the laminar airflow HEPA filter cohort (100 men, mean age [SD] 70 [±10] years old). The surgical indication was chronic lower limb ischemia in 97% and 94% of the cases, respectively. SSI cumulative incidence was 15,4% (12/78; 95%CI: 9,0-25,0%) and 14.8% (18/122; 95%CI: 9,5-22,1%), respectively, p-value≈1. SSI-associated predictive factors were chronic renal failure (OR: 2,7; 95%CI: 1,14-6,2; p-value: 0,021), and body mass index (OR: 1,47; 95%CI: 1,01-2,14; p-value: 0,040)(Figure 2).
Conclusion:
No decrease in SSI incidence has been observed since laminar airflow HEPA filters have been installed in the operating rooms. Chronic renal failure and body mass index are independent risk factors for SSI.
References:
1. Perencevich EN, Sands KE, Cosgrove SE, Guadagnoli E, Meara E, Platt R. Health and economic impact of surgical site infections diagnosed after hospital discharge. Emerg Infect Dis. 2003;9(2):196-203. doi:10.3201/eid0902.020232 2. Iudicello S, Fadda A. A Road Map to a Comprehensive Regulation on Ventilation Technology for Operating Rooms. Infect Control Hosp Epidemiol. 2013;34(8):858-860. doi:10.1086/671261 3. Dharan S, Pittet D. Environmental controls in operating theatres. J Hosp Infect. 2002;51(2):79-84. doi:10.1053/jhin.2002.1217
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