Vertical laminar air flow – the most efficient way to control microbe levels in an operating theatre.
“The purpose of ventilation in the operating theatre is to minimise the risks to patients and wounds of contaminants from human and other unsterile sources. Air ventilation also removes any anaesthesia gases that escape into the air.” (Ekono Oy. Energy Savings and Hospital Hygiene, Helsinki).
The Kojair laminar flow unit is a flexible, total solution
The Kojair laminar flow unit is factory-tested and ready to use. An operating theatre module can include general lighting, gas, oxygen and electrical connections and exhaust fittings. The fans can be located in the same room as the hospital A/C machinery.
When a laminar flow unit is placed in a modernised space, the filter units in the operating theatre can house the circulating fans. In this way, replacement air can be supplied through the existing air-conditioning system.
Kojair has supplied air conditioning to operating theatres since 1983. A major share of our production is marketed abroad. Our diverse and extensive experience in all the different areas of clean-air needs is an integral of the product.
Kojair is a comprehensive supplier. We are able to keep any system we supply running reliably. Every Kojair laminar flow unit has been thoroughly tested and can be delivered fully installed and ready to use.
“Effective air conditioning in operating theatres is a good investment.”
Research findings about air conditioning in operating theatres
The findings below were taken from an EKONO Oy study, “Energy Savings and Hospital Hygiene,” Helsinki 1990, performed for the Hospital Association of Finland. The rates for post-operative infections after orthopaedic knee and hip surgery are twice as high for surgery performed in theatres with conventional ventilation systems as compared to theatres ventilated with laminar air flow through a perforated cover.
Compared to conventional turbulent ventilation, vertical laminar flow can decrease the number of post-operation infections by half. In several studies made of air-exchange systems for entire operating theatres, the superiority of vertical laminar air flow has been conclusively established. In laminar air flow, the entire air mass circulates in one direction and displaces the existing air in the operating area. In a ventilation system based on vertical laminar flow, the incoming air is blown straight down through micro filters above the operating table. The downward air flow prevents air masses from mixing in the work area. Air in the operating area is changed 400 times per hour and at least 20 times per hour in the entire room. 20% of the air mass is vented out of the room and replaced by fresh air. 80% of the air in the room is circulated, filtered with the replacement air and blown back into the room. In this way, increased amounts of fresh air are not needed compared to conventional systems, which keeps energy costs down.
The operating theatre is the source of more than one quarter of all infections from hospital sources. This contributes to the ever-higher costs of medical care in the form of longer hospital stays and higher insurance payments. Effective air conditioning in the operating theatre is a key preventive measure, along with advanced surgical techniques and the correct use of antibiotic prophylaxis.
Air ventilation technology is especially important for orthopaedic, neuro-, heart and micro-surgery, all of which demand exceptionally sterile conditions. According to research, direct contact and airborne contaminants account for 98% of the micro-organisms that come into contact with the wound during major surgery. On the other hand, infections acquired after surgery requiring less-sterile conditions are usually caused by micro-organisms outside the operating theatre.
When operations requiring extremely sterile conditions are performed daily, and hospital stays are increased an average of two weeks by infections, effective air conditioning in operating theatres quickly pays for itself. The difference in price between a conventional turbulent ventilation system and a laminar flow unit is covered in just a few months by improved hygiene and lower health care costs.
Air distribution Number of Mikrobe levels (CFU/m3) Mikrobe levels (CFU/m3)
operations average range average range
Conventional turbulent 2755 194 51-396
Wall blowers 196 48 25-70
Vertical laminar flow 396 12 5-20
Cleanroom unit (vertical) 380 1.5 1.1-1.9
Alander ceiling 247 56 25-89
Trexler envelope isolator 338 0.7 0.15-1.5
Microbe levels in operating theaters equipped with different air ventilation methods; surgical team wearing conventional, cotton surgical gowns. Slit sampler or filter measurements.
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