Feasibility of Perioperative Stellate Ganglion Blocks in Cardiac Surgery

Summary

Based upon Northern New England Cardiovascular Study Group data, the rate of post operative atrial fibrillation (POAF) requiring treatment following coronary artery bypass grafting (CABG) at Maine Medical Center (MMC) is currently 30%. Nationally, POAF occurs in up to 40% of patients post CABG, 50% of patients after valve surgery, 64% of patients post mitral valve and CABG and 49% after aortic valve replacement. Atrial fibrillation worsens a patient's hemodynamic status and increases the risk of congestive heart failure (CHF), embolic events and longer ICU stays leading to increased patient morbidity and strain on financial resources. In the U.S., POAF carries a higher risk of stroke (37% OR 2.0 in-hospital mortality (OR = 1.7), worsened survival (74% versus 87%), and an additional 4.9 days and $10,000-$11,500 in hospital stay costs.

Atrial fibrillation requires both an initiation trigger and favorable environment for maintenance and the sympathetic and parasympathetic nervous systems play important roles in this regard. Unfortunately, the precise mechanisms of POAF are still being investigated. This postoperative complication has persisted in spite of efforts to mitigate it pharmacologically with beta blockers and amiodarone, an experience shared by most other cardiac surgery centers.

The stellate ganglion is formed by the fusion of the inferior cervical sympathetic ganglion and first thoracic sympathetic ganglion. By modulating the sympathetic component of the autonomic nervous system, stellate ganglion stimulation has been shown to facilitate induction of atrial fibrillation while ablation may reduce or prevent episodes. Human studies have further supported this model.

Preliminary studies of perioperative stellate ganglion block (SGB) in cardiac surgery suggest that this technique may reduce or prevent episodes of POAF requiring treatment. The investigator's ultimate goal is to determine whether SGB reduces the incidence of POAF in specific cardiac surgery populations at MMC. First, however, the investigator proposes to test the hypothesis that SGB, performed perioperatively by cardiac anesthesiologists in a population of patients undergoing cardiac surgery, is both safe and clinically feasible.

Conditions

• Atrial Fibrillation

Interventions

PROCEDURE

Stellate Ganglion Block

After induction of general anesthesia, patients will receive a stellate ganglion block using a standard and well described paratracheal technique, which typically requires about 3 minutes to perform. The patient's head will be extended and a 4-5-cm, 22-gauge needle inserted at the medial edge of the sternocleidomastoid muscle just below the level of the cricoid cartilage at the level of the transverse process of C6 (Chassaignac's tubercle) or C7 (3-5 cm above the clavicle). The non-operative hand will retract the muscle together with the carotid sheath prior to needle insertion. After advancing to the transverse process the needle will be withdrawn 2-3 mm prior to injection. A negative aspiration test will be performed in two planes before a 1-ml test dose is used to exclude unintentional intravascular injection (vertebral or subclavian arteries) or subarachnoid injection into the dural sleeve.4 A total of 10 ml of 0.25% bupivacaine will be injected.

Sponsors & Collaborators

• Christopher Connors, MD

  lead OTHER

Principal Investigators

• Christopher Connors, MD · MaineHealth

Study Design

Allocation

NA

Purpose

PREVENTION

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2016-05-31

Primary Completion

2016-12-06

Completion

2016-12-07