Argon Plasma Coagulation (APC) is used to achieve hemostasis and ablate intraluminal lesions in the respiratory tract. APC is regarded as a safe and effective modality, but gas embolism causing cardiac arrest has been reported. This study is being conducted to determine the true incidence of gas embolism during the use of APC by performing concurrent transesophageal echocardiography (TEE).
Informed consent for TEE was obtained from patients undergoing therapeutic rigid bronchoscopy. TEE was recorded during jet ventilation alone and during the use of APC.
From July 2008 to April 2009, 15 patients (9 female) underwent therapeutic rigid bronchoscopy. Indications included: hemoptysis (3), central airway obstruction (7), and granulation tissue ablation (5). Location of lesions included right mainstem bronchus (4), trachea (3), left upper lobe (2), right upper lobe (3), left mainstem bronchus (2), and no endobronchial lesion (1). No patients had intracardiac shunt by TEE Doppler. Mean argon flow rate was 1.7 L/min (range 0.5–2.0). Mean power used was 35 watts (range 30–40). Mean jet ventilation pressure used was 32 psi (range 22–42). One patient displayed gas bubbles in the left ventricle during jet ventilation alone as intratracheal saline was instilled; APC was not used in this case. In 2 patients, gas bubbles were noted in the left atrium and left ventricle during APC; in 1 of these patients, there was associated right ventricular hypokinesis, transiently. Both patients had right upper lobe central airway obstruction due to malignancy. No gas bubbles were noted in the other 12 patients. All 15 patients were at their neurological baseline following the procedure.
At the reported settings, APC may be associated with endovascular gas transfer and this phenomenon may be related to the location of the lesion.
Gas embolism may have clinical sequelae in certain patients. Therefore, those undergoing APC should have close electrocardiographic monitoring to serve as an initial indicator of this process.
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