Infection Risk in Pneumatic Motors

Infection Risk in Pneumatic Motors - Does Air Increase Contamination?

Surgical power tool systems used in orthopedics and traumatology surgeries are produced with pneumatic, electrical or battery options. With the development of lithium-ion battery technology, the most preferred option recently is battery-powered systems, as they make it easier to use during surgery. However, pneumatic systems continue to be used in many hospitals, as they are thought to have fewer malfunction causes. In this article, we’ll try to explain to you “Infection Risk in Pneumatic Motors”.

The working principle of pneumatic systems is that converting compressed air into mechanical energy and rotating the motor. Therefore, the air that moves through the motor must be expurged. In surgical power tools, the exhaust mechanism is located under the handle where the surgeon holds the motor. For this reason, it is very close to the area where the surgical procedure is performed. In some power tool systems, this exhaust air is expurged directly with a separate outlet. In newer systems, air inlet and outlet are provided from the same place.

So does this exhaust air increase contamination?

In a study conducted by H.C. Sagi et al in 2002, they evaluated the ability of exhaust air from compressed air surgical power tools used in orthopedics to create bacteria and contaminate sterile surfaces in the surgical field.

Part of the study consists of directing the air from the exhaust part to the agar plate (It is used for the detection of microorganisms).  The experiments were carried out with two different pneumatic power tools at different distances (10, 20 and 30 cm), with different durations (15 and 30 seconds).  At the same time, it was tried in two ways, as in Figure 1 and Figure 2, so that the exhaust air would not affect the results by contacting the surgeon’s gloves or apron. In another section, the comparison of pneumatic power tools and battery power tools is made.

Figure 1: Hand holding the pneumatic power tool in normal way above agar plate. (H.C. Sagi et al., 2002)

Figure 2: Hand holding the pneumatic power tool by barrel section above agar plate. (H.C. Sagi et al., 2002)

When this air was directed onto sterile agar plates, the exhaust air from the pneumatic power tool number 1 revealed positive cultures in 8 of the 11 samples (72.7%). Exhaust air from the pneumatic power tool number 2 revealed a positive culture in 9 of the 11 samples (81.8%).

For comparison, a pneumatic power tool and a battery power tool were similarly operated above agar plates. It was observed that the battery power tool produced no bacteria at 0% (0 out of 6), while the air motor produced 77% (17 out of 22) bacteria.

In these trials, it is seen that the exhaust air from pneumatic power tool causes bacteria to accumulate on sterile surfaces. The short period of use should be considered for the low colony counts found on agar plates (10 to 30 seconds). The usage time of these devices in actual operation varies between 5 and 10 minutes. Therefore, the cumulative effect should be calculated.

Based on these results, H.C. Sagi et al. (2002) recommend pneumatic power tools that capable of removing exhaust air from the operating area or battery power tools to reduce the risk of intraoperative contamination.

According to this study, pneumatic systems cause the formation of microorganisms. In new pneumatic systems, the incoming air is removed from the sterile zone. However, the most common malfunction in pneumatic systems is the formation of punctures and tears at the connection point of the hose where the air flow is provided to the power tool. These punctures and tears are not always noticeable at the moment they occur. This reveals the risk of unnoticed bacterial contamination of sterile surfaces within the operative field and infection of the patient.

For the other articles please click here.

Click here to find more articles about Infection Risk in Pneumatic Motors via PubMed.

Share This Post :



  • H.C. Sagi, Thomas Di Pasquale, Roy Sanders and Dolfi Herscovici. 2002. Compressed-Air Power Tools in Orthopaedic Surgery: Exhaust Air Is a Potential Source of Contamination. Journal of Orthopaedic Trauma. Vol. 16, No. 10, pp. 696–700. Williams & Wilkins, Inc., Philadelphia.

Related Posts