AGMP or Aerosol Generating Medical Procedures

Use of the Yankauer suction catheter is a classic example of a high risk medical Aerosol Generating Medical Procedure, or AGMP that can result in the release of infective contaminants into the surrounding environment (24). Commonly performed in both pre- hospital care and in multiple levels of healthcare facilities worldwide, open airway suctioning is generally conducted when airway compromise exists or is anticipated. This procedure is implemented by first responders, paramedics, nurses, physicians, and respiratory therapists daily and is recognized by the College of Respiratory Therapists of Ontario as “an AGP with conclusive evidence of transmission of infective agents” (30). In addition, introducing the Yankauer into the oral cavity, and the suctioning process itself, also promotes coughing, gagging, and spitting by the patient due to gag reflex.

Frequently when airway therapy is performed, patients are encouraged to cough and assist in clearing their own airway (31). This action propels infectious agents often in a conical cloud completely uncontrolled. Endotracheal intubation and all airway management procedures require the utmost attention in close quarters to achieve good visualization and technique, thus facial proximity and body positioning results in a higher risk of exposure to the health-care worker who performs AGMP’s (24).

After its initial use, the Yankauer can sometimes go back into its original envelope – a common practice in many hospital and other healthcare settings. However, with subsequent uses that may occur over a matter of minutes, the Yankauer quickly becomes sticky and contaminated. Often the dirty Yankauer is slid under the patient’s pillow or on their chest to secure it. Other times, the used catheter may sit in its envelope taped to a wall or bed-railing for extended periods, preventing the residual fluids from drying and encouraging bacterial growth. It is not uncommon that the Yankauer will fall to the floor, dragged by the weight of its own tubing, thereby picking up and depositing contaminants and infectious agents wherever it touches. A study conducted on the contamination of Yankauer suction catheters in ICUs in the US demonstrated a colonization rate of 80% for one or multiple pathogens. The Yankauers collected for this study were found on the patient’s bed, on top of medical equipment, or in a designated holder (12). Reintroducing a Yankauer carrying the patient’s own germs is one issue, but an instrument contaminated by external sources is far more questionable.

Incision and drainage (I&D) procedures are commonly performed in clinics and hospitals for the treatment of an abscess. Frequently under tension, incisions of these abscesses can result in the explosive release of an exudate and spray. Graphically, think pus and blood. The pathogenic material can land on surrounding environment, including surfaces in the room and on HCWs. Although appropriate PPE is usually worn, it does little to control the spread of the contaminant. The gear provides protection only to specific areas of the healthcare providers body and only if properly worn. Again, PPE may provide a vehicle for the transmission of infectious agents through self- contamination of the wearer and further the spread of the pathogens (24, 26-27).

Forceful irrigation of wounds with copious amounts of solution is a frequently executed procedure in the ER, clinics and surgical suites. This intervention is used to remove debris and contaminants and to enhance injury visualization. Wound irrigation is considered to be an effective method of wound cleansing (15) and when combined with debridement, is a crucial step in healing that can be impeded by debris. Although the ideal pressure that irrigation is delivered has yet to be determined and is dependent upon the nature of the wound, higher pressures are generally recommended to adequately remove contaminants and mitigate the potential for infection (14, 15). A recent review of current procedural outlines for wound irrigation all forewarn the high potential for splashes during irrigation and contamination of the HCWs and the surrounding environment (14, 15).

Another procedure that can involve dynamic contamination of the medical environment and potential HCW exposure is the irrigation of Foley type catheters. Syringe driven irrigation or medication delivery of Foley-type urinary catheters can result in infection laden urine being sprayed uncontrollably in any direction when the catheter is obstructed or blocked. This can obviously add significantly to the bio- pathogenic load of the healthcare facility. A frequent injury incurred by HCWs is urine splashing into the eyes (17). These same issues arise with the irrigation and medication insulation to J and G-tubes.

Naso-gastric or NG extubation or removal commonly results in what I term “whip- splash”. Whip-splash occurs when the last 6 inches of the tube are withdrawn from the nare, under some degree of rotational and directional stress. Immediately when the tip leaves the nostril it aligns to it’s desired structural shape resulting in whip of the tip and an arc of nasal, esophageal, pulmonary and gastric contaminants . Yes, pulmonary, as there is a shared pathway from the nasal passages through the oral-pharynx into the esophagus.

Other, more dramatic but less common aerosol generating medical procedures include emergency tracheostomies and thoracostomies performed in the event of un- resolvable airway obstruction and the tension pneumothorax respectively. both of these can spray a mist and spurt of blood, pus or other infective agents metres in any direction. Uncontrolled.

In our next posting we’ll discuss how Prodaptive was saved a significant portion of these problems, specifically focussed on blocking the dynamic, and static, contamination related to these procedures and more.

Note: This document has been edited. Original text and references can be found on the original document on our website

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