ACE-CAA Issue 2 Sample Question
A patient with a cardioverter-defibrillator implanted in the left pectoral region is to undergo tracheostomy and mandibular resection with reconstruction. Based on the image, which letter corresponds to the MOST appropriate site to place the electrosurgery unit dispersion pad?
Answer: (A) The patient's right shoulder. Read the discussion below.
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Electromechanical interference (EMI) poses a risk for patients with implanted cardiac rhythm–management devices. Most modern devices are highly unlikely to undergo inadvertent reprogramming due to EMI exposure. However, exposure to strong EMI could cause an electrical reset or false interpretation of battery life, potentially leading to a change in heart rate or pacemaker mode. Inappropriate delivery of high-energy tachyarrhythmia therapy (either antitachycardia pacing or shock) from a cardioverter-defibrillator can be associated with myocardial injury, as evidenced by troponin elevation or electrocardiographic changes consistent with injury.
The greatest source of EMI in the operating room is the electrosurgical unit. A monopolar electrosurgical unit set to a blended coagulation mode emits the greatest amount of EMI compared to other types and modes of use.
The electrosurgical dispersion pad should be placed so that the current path traveling from the handheld instrument to the unit (Figure 1) does not cross the pacemaker or its leads. A patient having head and neck surgery should have the dispersion pad placed on the shoulder contralateral to the implanted device. For breast or axillary cases, the pad may need to be placed on the arm ipsilateral to the device.
Figure 1. The path of current flow and implanted cardiac rhythm management device interference. (A) High risk of interference. (B) Low risk of interference. © 2018 American Society of Anesthesiologists.
Kaplan JA, Augoustides JGT, Manecke GR Jr, Maus T, Reich DL, eds. Kaplan’s Cardiac Anesthesia for Cardiac and Noncardiac Surgery. 7th ed. Philadelphia, PA: Elsevier Saunders; 2017:126.
Rozner MA, Kahl EA, Schulman PM. Inappropriate implantable cardioverter-defibrillator therapy during surgery: an important and preventable complication. J Cardiothoracic Vasc Anesth. 2017;31(3):1037-1041.