Abstract ID: A23
Abstract Title: Postoperative Pain Control With An Opioid-Based Thoracic Epidural In A Patient With Idiopathic Hypertrophic Subaortic Stenosis
Poster Type: Poster
ABSTRACT BODY
Introduction: Idiopathic Hypertrophic Sub-Aortic Stenosis (IHSS) is an autosomal dominant genetic defect, which is manifested as myocardial hypertrophy, especially of the interventricular septum, and can produce outflow obstruction. Events that increase outflow obstruction are: decreased preload or afterload and/or increased contractility. Some clinicians believe that regional anesthesia should be avoided in these patients because of its propensity to decrease systemic vascular resistance.
Postoperative pain relief can be difficult in these patients, and pain-related tachycardia may be detrimental to patients’ hemodynamics. Prospective, randomized studies of hemodynamic changes in IHSS patients undergoing regional anesthesia have not been conducted.
Case Report: A 55 year-old female with history of IHSS, tobacco abuse, COPD, and a right common bile duct stricture, presented with pathology suggestive of atypia and requiring a Whipple procedure. Pre-anesthesia consultation was obtained and the patient was counseled regarding the need for invasive monitoring and use of a thoracic epidural for postoperative pain control. An echocardiogram showed a severely hypertrophic interventricular septum with left ventricular outflow obstruction and an LVEF of 60-65%. Lung fields were clear to auscultation. A grade III/VI holosystolic murmur was heard over the right second intercostals space. The electrocardiogram revealed a sinus rhythm in the 70’s.
The patient received arterial and pulmonary artery catheters prior to induction of anesthesia. A T8 thoracic epidural was placed and, following a negative test dose of 2.5 ml of 1.5% lidocaine with 1:200,000 epinephrine, 0.5 mg of hydromorphone administered epidurally. Following induction of general anesthesia, the epidural was bolused with 6 ml of hydromorphone (0.1 mg/ml) every 30 minutes. Blood pressure was stable throughout the procedure. The systolic pulmonary arterial pressure ranged from 32-45 cm H20; central venous pressure (CVP) was 12 to 17 cm H20.
Postoperative analgesia was maintained with a hydromorphone infusion ranging from 8-12 ml/hour (0.1 mg/ml). The patient had mild pruritis, which was relieved by antihistamines, but recovery was otherwise uneventful. The epidural catheter was removed on post-operative day 4, and patient was discharged home 4 days later.
Discussion: There have been conflicting reports relating to the SVR decrease with epidural techniques using local anesthetics. Ueland et al. and Brian et al. found no decline in SVR following epidural for Cesarean-section1,2. Bonic et al. studied healthy non-pregnant volunteers and reported that epidural anesthesia in the absence of epinephrine with a sensory level at T5 produced a 5% decrease in mean arterial pressure, a 6% increase in cardiac output, and a 10% decrease in peripheral resistance3. Although most clinicians will shy away from regional techniques in patients with IHSS, there have been a few reports of successful use in parturients at term with aortic stenosis, a similar disease process.3 There are no studies reporting their use in patients undergoing non-obstetrical abdominal surgeries.
In this case study, a thoracic epidural using only hydromorphone was used successfully to control post-operative pain after a Whipple procedure. The initial intention was to monitor our patient’s hemodynamics closely with pulmonary arterial catheter and administer local anesthetics as tolerated. Epidural opioid alone was found to be sufficient in our patient, so no local anesthetic was added. Additional studies are needed to evaluate the suitability of utilizing regional anesthesia (+/- local anesthetic) in patients with IHSS.
ATTACHED FILES
Reg Anesth Pain Med 2004; 29(2):A23