A Method for Slow Epidural Dosing and Two Case Reports of its Successful Use in Parturients with Hypertrophic Obstructive Cardiomyopathy
Abstract Number: F-67
Abstract Type: Case Report/Case Series
HCM is a genetic heart disease presenting with a wide spectrum of clinical effects. Maternal stress, catecholamine release and large volume fluid shifts that accompany labor and delivery can acutely lead to cardiac failure and an increased maternal mortality. Slow-dosing has been advocated to allow both the body and the anesthesia team time to compensate for sympathectomy-related hypotension. However, practitioners disagree on the definition of “slow-dosing.”  We present a method of gradually dosing an epidural catheter for anesthesia for cesarean used successfully twice in parturients with HCM.
After placement of the epidural, a 3mL test dose using 1.5% lidocaine with 1:200,000 epinepherine was administered. A colloid co-load was administered and the epidural catheter was serially dosed every 5 minutes after ensuring cardiovascular stability with 5mL of 0.0625%, 0.125%, and 0.25% bupivicaine. After again ensuring cardiovascular stability, two 5mL boluses of 0.5% bupivicaine were given 5 minutes apart. Gradually increasing concentrations of local anesthetic allowed for a gradual increase in the density of blockade without the onset of refractory hypotension.
A 39-year-old G5P4 with HCM and hypertension presented at 36 5/7 weeks. HCM and severe hypertension had been diagnosed ten years before. She denied any history of syncope but endorsed dyspnea and palpitations. The patient was noncompliant with her medications. TTE five days antepartum showed severe LVH with an EF of 70%. The LVOT peak pressure was 38 mmHg. The rest of the exam was grossly normal. An arterial line was placed and epidural anesthesia was achieved using the method described above. Morphine 3mg and fentanyl 100mcg were also injected, achieving a bilateral T4 block. The patient remained hemodynamically stable during and after epidural bolus. Crystalloid 500mL and 5% albumin 1250mL were administered. EBL was 500mL and urine output was 50mL. The patient recovered well and was discharged home in good condition.
A 32 year old G9P5 with HCM presented at 32 0/7 weeks. Septal alcohol ablation had been previously attempted and an ICD was placed. The patient complained of chest pain, dyspnea, and syncope. Her TTE revealed a peak left ventricular outflow tract gradient of 140 mmHg, moderate MR, and EF of 70%. Her epidural was dosed as described above and achieved a T6 block. A phenylephrine infusion was begun after test dose and stopped before incision. No further doses of pressors were required. LR 2500mL and 5% albumin 500mL were administered. EBL was 400mL and UOP was 200mL. The patient remained hemodynamically stable. The patient’s postoperative course was uneventful.
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2. Ginosar Y, et al. Sympathectomy-mediated vasodilatation: a randomized concentration ranging study of epidural bupivacaine. Can J Anaesth 2009;56:213-21.