Blocks Alternative to Sedation

Overview

Current practice is to implant cardiac electronic devices using intravenous sedation with midazolam and fentanyl, as well as local injection of anesthetic (1-2). However, some patients do not tolerate sedation and develop nausea/vomiting, delirium/confusion, allergic reactions, and hemodynamic instability with sedation (2-4). Many patients are poor candidates for procedural sedation due to inadequate fasting before the procedure or prior adverse effects of procedural sedation. Pain control is usually adequate, but a large portion of patients still experience pain or discomfort at the implant site if the local anesthetic did not reach every component of the tissue in the surgical field. Meanwhile, nerve block procedures have been used for decades to improve peri-operative and post-operative pain and reduce sedation requirements. With the introduction of ultrasound, the investigators are able to direct delivery of local anesthetic to anesthetize the supraclavicular and pectoralis nerves that supply sensory/pain sensation to the surgical site. Similar techniques have been well described as safe and effective (5-10). The investigators hypothesize this will improve pain control during and after surgery, reduce or eliminate the need for intravenous sedation and improve the safety of the procedure.

Inpatients who are consented to have cardiac device implantation will be given study information as soon as the decision to implant a device is reached. The patients will have time to decide to participate in the study up until they are called for the procedure (2-72 hours, most commonly \> 24 hours). The decision to participate in the study is conveyed to the investigator in the holding room, and written consent is obtained if the patient agrees to participate in the study. The nerve block is performed in the holding room as a 2-step procedure by trained physicians. After the nerve block approximately 30-60 minutes will be allowed for the anesthetic to take effect prior to the cardiac device implantation procedure. The patient will be monitored by the nurses in the holding room. Once the patient is taken to the operating room and prepped for the cardiac device implantation procedure, testing of the nerve blocks is performed. The superficial pin-prick test will be performed to determine the success of the SCN block, and a deeper test will be performed with a 22ga needle to ensure the deeper muscular layers are anesthetized and the PECs I block is successful. If both blocks are successful, the patient will receive optional light sedation with midazolam 0.01 mg/kg based on their preference, and the procedure can commence. If either the SCN or PECs blocks are not successful based on the sensation test, usual care is provided. Immediately after the procedure, the patient is asked to rate the pain during the procedure on a numerical scale. Any adverse effects reported by the patient will be documented. The patient will then be reassessed 1 hour after the procedure in the holding room and then called the following day. One of the investigators will contact the patient by telephone on the following day (24hr later), and perform a similar assessment. The assessment will involve inquiring how the patient is feeling, documenting any unintended adverse effects, and asking the patient to rate their pain on a numerical scale.