Survey on Bioaerosols Type and Density and Ach Index Impact on BioaersolsDensity in Heart Surgery Rooms and Cardiac Surgery IntensiveCare Unit in a Teaching Hospital in Ghazvin

摘要

The existence of biological aerosols in the operating room and surgical intensive care units is notonly considered as a threat for patients undergoing the surgery, but also it is an occupational hazard forpersonnel in the referred units. Ventilation systems of operating rooms have high potential to control thepostoperation infections. Therefore, the proper design and use of these systems is of particular importance.This cross-sectional study was conducted in heart surgery and cardiac surgery intensive care unit in springof 2015. In order to evaluate the microbial contamination of air, above than 93 samples were selected using aninactive method and they were incubated, then the number of colonies per plate was counted and was recordedas cfu/plate/h. In order to identify and examine the colonies, the gram stain and differential tests were used.Along with the sampling, data of temperature, humidity and pressure were assessed and the value of ACH (AirChange per hour) was calculated and recorded. According to the results, the numbers of colony forming unitsof bacteria and fungus in the cardiac surgery intensive care unit were higher than other units. The number ofcolony forming units in samples taken from the operating room was less than the guide rate of 25 cfu/plate/hand it was more than this amount in 2.4% of the samples in the cardiac surgery intensive care unit. Most of theobtained bacteria were Staphylococcus epidermidis and Staphylococcus saprophyticus and most abundantfungi belonged to Penicillium species, Curillophyllum and Cladspurium cladspuriudis. ACH rate in the operatingrooms was <20ACH which is the guide rate for operating room and it was >6 ACH, the guide rate for the cardiacsurgery intensive care unit. Most of bacterial and fungal colonies were recorded in the cardiac surgery intensivecare unit. It seems that one of the reasons was the large number of people (patients and staff) in this unit.Additionally, despite the suggested ACH rate had been supplied in this unit, however the density of thebioaerosols in this unit was higher than the guide rate that the entry and exit of air and location of the input andoutput doors have played important roles to this increased levels of bioaerosols. Therefore, to meet the ACHguide rate cannot ensure the risk reduction of bioaerosols necessarily and this issue and the other factorsshould be well considered in the design and control of ventilation systems for the different units of thehospitals particularly the surgical ward.