Can clothing systems and human activities in operating rooms with mixing ventilation systems help achieve 10 CFU/m3 level during orthopaedic surgeries?

Baseline Study of Ultra-Clean Air Change Rate, Number, and Type of Microorganisms and Level of Particles During Trauma Surgery

Background: The objective of an operating room (OR) ultra-clean ventilation system is to eliminate or reduce the quantity of dust particles and colony-forming units per cubic meter of air (CFU/m3). To achieve this, ultra-clean goal high air change rates per hour are required to reduce the particle load and number of CFU/m3. Aim: To determine the air quality in an ultra-clean OR during surgery, in terms of the number and type of microorganism and quantity of dust particles in order to establish a benchmark. Methods: Number of CFUs and the quantity of dust particles were measured. For measuring the CFUs, sterile extraction hoses were positioned at the incision, the furthest away positioned instrument table, and the periphery. At these locations, air was extracted to determine the quantity of dust particles. Findings: The number of CFU/m3 and particles was on average at wound level ≤1 CFU/m3 resp. 852.679 particles, at instrument table ≤1 CFU/m3 resp. 3.797 particles and in the periphery ≤8 CFU/m3, resp. 4.355 particles. Conclusion: The number of CFUs in the ultra-clean area is below the defined ultra-clean level of ≤10 CFU/m3 for ultra-clean surgery. The quantity of dust particles measured during surgery was higher than the defined ISO 5.

Comparison of number of air-borne bacteria in operating rooms with turbulent mixing ventilation and unidirectional airflow when using reusable scrub suits and single-use scrub suits

INTRODUCTION

Low counts of air-borne bacteria in the operating room is a mean to prevent surgical site infection.

AIM

To investigate levels of air-borne bacteria during surgical procedures in two operating rooms with turbulent mixing ventilation (TMV) and unidirectional airflow (UDAF), both with an air supply of 2600 L/s, when staff used either reusable scrub suits made from a mixed material (dry penetration ≤ 300 CFU) or single-use scrub suits made from polypropylene (dry penetration ≤ 100 CFU).

MATERIAL AND METHODS

In the TMV-room colony forming units (CFU) per m³ air was measured during eight procedures with staff wearing reusable scrub suits and seven procedures with single-use scrub. In the UDAF-room CFU/m³ air was measured during seven procedures with staff wearing reusable scrub suits.

FINDINGS

Mean values of CFU/m³ air were 1.3 to 10.8 in the TMV-room with staff dressed in reusable scrub suits and 0.8 to 4.0 with staff dressed in single-use scrub suits (p < 0.01). Mean values of CFU/m³ air were 0.2 to 4.5 in the UDAF-room with staff dressed in reusable scrub suits. The difference obtained with reusable scrub suits in the two rooms was significant (p < 0.01).

CONCLUSIONS

The mode of ventilation affects the CFU-levels when staff is dressed in less occlusive scrub suits despite a high air supply. It is possible to decrease the CFU-levels in a TMV-room by using scrub suits made from a tight material thus reaching the same levels that are achieved by less protective scrub suits in a UDAF-room.

Operating room ventilation systems: Recovery Degree, Cleanliness Recovery Rate and Air Change Effectiveness in an ultra-clean area

BACKGROUND

Entrainment test methods are described in most European standards and guidelines to determine the protected area for Ultra-Clean Ventilation (UCV) systems. New UCV systems, such as temperature-controlled airflow (TcAF) and controlled-dilution ventilation (cDV) claim the whole Operating Room (OR) to be ultra-clean. Current test standards are not developed for assessing ventilation effectiveness outside the standard protected area.

AIM

To assess and compare the ventilation effectiveness of four types of OR ventilation systems in the ultra-clean area by using a uniform test grid.

METHODS

In this study the ventilation effectiveness (VE) of four ventilation systems is evaluated for three different ultra-clean (protected) areas; standard protected area (A), area outside standard protected area (B) and large protected area (AB). The VE is defined as the recovery degree (RD), cleanliness recovery rate (CRR) and air change effectiveness (ACE).

FINDINGS

RD, CRR and ACE were significantly higher for the Uni Directional Air Flow (UDAF) system when compared to the other systems in area A. In area B, UDAF and cDV were comparable regarding RD and CRR and UDAF and Conventional Ventilation (CV) were comparable regarding ACE. In area AB the UDAF and cDV were comparable regarding CRR and ACE but are significantly different in RD.

CONCLUSION

In area A the ventilation effectiveness of the UDAF ventilation system is outperforming other ventilation systems. In area B, cDV is performing the best followed by UDAF, TcAF and CV. In area AB, UDAF is performing the best followed by cDV, TcAF and CV.