Anesthesia care for subcutaneous implantable cardioverter/defibrillator placement: a single-center experience

The recently approved subcutaneous implantable cardioverter/defibrillator (S-ICD) uses a single extrathoracic subcutaneous lead to treat life-threatening ventricular arrhythmias, such as ventricular tachycardia and ventricular fibrillation. This is different from conventional transvenous ICDs, which are typically implanted under sedation. Currently, there are no reports regarding the anesthetic management of patients undergoing S-ICD implantation.

This study describes the anesthetic management and outcomes in patients undergoing S-ICD implantation and defibrillation threshold (DFT) testing.

The study population consists of 73 patients who underwent S-ICD implantation. General anesthesia (n = 69, 95%) or conscious/deep sedation (n = 4, 5%) was used for device implantation.

Systolic blood pressure (SBP) and heart rate were recorded periprocedurally for S-ICD implantation and DFTs. Major adverse events were SBP <90 mm Hg refractory to vasopressor agents, significant bradycardia (heart rate <45 beats per minute) requiring pharmacologic intervention and, "severe" pain at the lead tunneling site and the S-ICD generator insertion site based on patient perception.

Of the 73 patients, 39 had SBP <90 mm Hg (53%), and intermittent boluses of vasopressors and inotropes were administered with recovery of SBP. In 2 patients, SBP did not respond, and the patients required vasopressor infusion in the intensive care unit.

Although the S-ICD procedure involved extensive tunneling and a mean of 2.5 ± 1.7 DFTs per patient, refractory hypotension was a major adverse event in only 2 patients. The mean baseline SBP was 132.5 ± 22.0 mm Hg, and the mean minimum SBP during the procedure was 97.3 ± 9.2 mm Hg (P < .01). There was also a mean 13-beats per minute decrease in heart rate (P < .01), but no pharmacologic intervention was required. Eight patients developed "severe" pain at the lead tunneling and generator insertion sites and were adequately managed with intravenous morphine.

Among a heterogeneous population, anesthesiologists can safely manage patients undergoing S-ICD implantation and repeated DFTs without wide swings in SBP and with minimal intermittent pharmacologic support.