Effect of unidirectional airflow ventilation on surgical site infection in cardiac surgery: environmental impact as a factor in the choice for turbulent mixed air flow.

BACKGROUND: Surgical site infection (SSI) in the form of postoperative deep sternal wound infection (DSWI) after cardiac surgery is a rare, but potentially fatal, complication. In addressing this, the focus is on preventive measures, as most risk factors for SSI are not controllable. Therefore, operating rooms are equipped with heating, ventilation and air conditioning (HVAC) systems to prevent airborne contamination of the wound, either through turbulent mixed air flow (TMA) or unidirectional air flow (UDAF). AIM: To investigate if the risk for SSI after cardiac surgery was decreased after changing from TMA to UDAF. METHODS: This observational retrospective single-centre cohort study collected data from 1288 patients who underwent open heart surgery over 2 years. During the two study periods, institutional SSI preventive measures remained the same, with the exception of the type of HVAC system that was used. FINDINGS: Using multi-variable logistic regression analysis that considered confounding factors (diabetes, obesity, duration of surgery, and re-operation), the hypothesis that TMA is an independent risk factor for SSI was rejected (odds ratio 0.9, 95% confidence interval 0.4-1.8; P>0.05). It was not possible to demonstrate the preventive effect of UDAF on the incidence of SSI in patients undergoing open heart surgery when compared with TMA. CONCLUSION: Based on these results, the use of UDAF in open heart surgery should be weighed against its low cost-effectiveness and negative environmental impact due to high electricity consumption. Reducing energy overuse by utilizing TMA for cardiac surgery can diminish the carbon footprint of operating rooms, and their contribution to climate-related health hazards.

[Steps for reducing the carbon footprint of the operating room]. / Manieren om de CO2-voetafdruk van de OK te verlagen.

The healthcare sector contributes significantly to global warming due to carbon emissions; this sector is, therefore, partially responsible for the negative effects of climate change on public health. Carbon emissions by the healthcare sector amount to 7% of the total carbon footprint of the Netherlands. It is anticipated that measures to reduce carbon emissions in the operating room (OR) can make an important contribution to reducing carbonemissions in the hospital as a whole. The most important elements contributing to the carbon footprint of the OR are: energy consumption for heating, ventilation and air conditioning (HVAC); the emission of inhalation anaesthetics; the purchase of materials and equipment; and waste production. Direct carbon emissions by the OR can be reduced through the use of sustainable energy and setback of the HVAC outside office hours. Anaesthetists can dramatically reduce the carbon footprint of the OR by choosing for intravenous anaesthetics instead of inhalation anaesthetics. Indirect carbon emissions and waste production by the OR can be reduced through circular procurement, choosing reusable over disposable products and recycling.