Surgical smoke evacuation

AORN Journal, June, 2008 by Ioan Cosmescu, Brenda C. Ulmer

I feel it is extremely important for all surgical team members to be aware of the hazards of surgical smoke and the ways to eliminate smoke. The article "The hazards of surgical smoke" (1) (Vol 87, April 2008) provides valuable information about surgical smoke for perioperative nurses, who must be diligent in the evacuation of all plume.

Although the article provides vital information, it has a misleading statement about the effectiveness of portable smoke evacuation systems. The statement in question reads:

   An effective portable smoke evacuation
   system should be able to pull 30
   cuff to 50 cuff per minute to be able
   to capture surgical smoke (1(p728)

The effectiveness of a smoke evacuator is not based on the cubic feet of air movement per minute. In 1997, Health Devices published information from the ECRI about surgical smoke evacuation systems. (2) The criteria used to determine smoke evacuation system efficiency were the airborne particle reduction, system exhaust performance, and odor capture and removal. (2(p152-157)

Additionally, smoke evacuator collection devices have been divided into two categories: pencil-based devices and handheld nozzle devices. The National Institute for Occupational Safety and Health (NIOSH) publication titled Hazard Controls: Control of Smoke from Laser/Electric Surgical Procedures (HC11) states

   The smoke evacuator should have high
   efficiency in airborne particle reduction
   and should be used in accordance with
   the manufacturer's recommendations
   to achieve maximum efficiency. A
   capture velocity of about 100 to 150
   feet per minute at the inlet nozzle is
   generally recommended. (3)

Neither the ECRI testing nor the NIOSH hazard controls have ever recommended that 30 cu ft to 50 cu ft of flow rate per minute is necessary for the smoke evacuator to be listed as efficient. The most important criterion for the efficiency of smoke evacuation is the velocity of the air intake at the nozzle. The higher the velocity, the higher the efficiency.

The flow created by the smoke evacuator, no matter how low or high--30 cu ft per minute, 50 cu ft per minute, or even 100 cu ft per minute--means nothing if it is not supported by high suction power, which actually creates the high velocity at the inlet nozzle. The flow also is affected by the diameter of the tubing and the nozzle. Obviously, the quality of the filtration also is very important as mentioned in the AORN Journal article.

So, in summary, the true measures of the efficiency of a smoke evacuator are the capture velocity at the inlet nozzle--which should not be less then 100 ft per minute to 150 ft per minute--and the quality of the three-stage filtration, as mentioned in the article.

Thank you for publishing this response so that perioperative nurses understand the true efficiency ratings of their smoke evacuators.

REFERENCES

(1.) Ulmer BC. The hazards of surgical smoke. AORN J. 2008;87(4):721-734.

(2.) Surgical smoke evacuation systems. Health Devices. 1997;26(4):132-172.

(3.) Hazard Controls: Control of Smoke from Laser/Electric Surgical Procedures (HC11). National Institute for Occupational Safety and Health. http://www.cdc .gov/niosh/hc11.html. Accessed May 6, 2008.

IOAN COSMESCU

PRESIDENT

IC MEDICAL, INC

PHOENIX, AZ

AUTHOR'S RESPONSE, My thanks to Mr Cosmescu for pointing out air velocity as one metric in determining capture efficiency of a smoke evacuator. The NIOSH does, indeed, use recommended velocity levels. My statement that smoke evacuators should be able to pull between 30 cu ft to 50 cu ft per minute (cfm) was not intended to be misleading. It is very common to refer to cubic feet per minute in relation to smoke evacuator efficiency:

* " ... an individual smoke evacuator may move air at 35 to 50 cfm." (1(p216))

* "... an individual smoke evacuator produces an air movement of 30-50 cfm. (2(p92))

* "Air movement, or suction ability, usually between 30-50 cu ft/min of air movement, is desired." (3(p129))

Air velocity measures the speed of air movement past a given point. The volume of air flow past a certain point is measured in cubic feet per minute. Air velocity can be converted to cubic feet per minute when the tubing size used with the smoke evacuator is known; likewise, cubic feet per minute can be converted to velocity. Perioperative professionals can make the conversion calculations at http:// www.thermaflo.com/airflow_conversion.shtml. This should help reduce any confusion or misunderstanding when different terms are used to express smoke evacuator capture efficiency.

Volumetric airflow stated as cubic feet per minute is one of the measures that the ECRI lists as being an important component of successful smoke capture, along with the position of the capture device and the type of tubing. (4(p334)) In 2001, the ECRI recommended that the smoke evacuation system airflow should have a rate of at least 35 cu ft per minute to capture smoke effectively. (5(p80) In November 2007, the ECRI airflow recommendation was readjusted to a minimum airflow value of at least 25 cu ft per minute. (6(p5) This adjustment was due to the use of smoke evacuation devices that attach directly to the electrosurgery pencil and are close to the site of surgical smoke production.