Effects of Postoperative Patient Controlled Epidural Analgesia in Pediatric Patients Undergoing Lower Extremity Surgery / 대한마취과학회지

BACKGROUND: A limited number of studies have been conducted on postoperative epidural analgesia in pediatric patients. There have been primarily dealt with spinal or abdominal surgeries where multiple dermatomal segments needed to be blocked and morphine was given either through the caudal approach or by direct catheter placement. This study evaluated the safety and efficacy of postoperative continuous patient controlled epidural analgesia (PCEA) in children undergoing lower extremity surgery using a bupivacaine and fentanyl via lumbar approach. METHODS: The patient population consisted of 40 children ranging in age from 5 to 12 years. Patients were randomly divided into two groups according to postoperative pain relief regimen; the control group received an intramuscular injection of ketorolac 1 mg/kg t.i.d. and meperidine 0.5 mg/kg p.r.n., and the epidural group received PCEA (0.1% bupivacaine + fentanyl 2 microgram/ml) through an epidural catheter positioned at the surgical dermatomal level of the spinal cord. In the epidural group the volume of the initial dose was 1 ml/segment in children 10 years of age. The basal infusion rate was 0.1 ml/kg/hr (bolus: 0.05 ml/kg, lockout time: 30 minutes). Pain scores were measured upon arrival at the ward, and 6 and 24 hours thereafter. RESULTS: The epidural group had significantly lower pain scores and minimal side effects. A significant correlation was observed between the bolus number and the incidence of nausea/vomiting in the epidural group. CONCLUSIONS: This study shows that PCEA targeted at the surgical dermatome is a safer and more effective regimen for postoperative pain relief than conventional postoperative pain relief in pediatric patients undergoing lower extremity surgery.

Effect of Small-dose Ketamine on Hemodynamic Changes during Lower Extremity Surgery Using a Tourniquet under General Anesthesia / 대한마취과학회지

BACKGORUND: A tourniquet is commonly used to achieve bloodless field in surgery of the extremities. However, use of tourniquet occasionally has been associated with intraoperative hypertension, but the mechanism of this tourniquet-induced hypertension is unknown. We investigated the effect of preoperative ketamine on tourniquet-induced changes of arterial blood pressure (BP), heart rate (HR), cardiac index (Ci), and systemic vascular resistance index (SVRi). METHODS: Twenty-two patients of ASA physical status class 1 and 2, scheduled for lower extremity surgery using a tourniquet, were randomly assigned into two groups. Anesthesia was maintained with 1.5-2.0 vol% enflurane and 50% N2O in O2 with endotracheal intubation. The changes of BP, HR, Ci, and SVRi were measured (1) at 10 minutes after induction, (2) at 10 minutes after injection of normal saline (control group) or ketamine 0.25 mg/kg, i.v. (ketamine group) before skin incision and tourniquet inflation, (3) at immediately and 5, 10, 15, 20, 30, and 40 minutes after inflation of tourniquet, and (4) immediately after deflation of tourniquet. RESULTS: During tourniquet inflation, BP and HR were not significantly changed in each group and there was no significant differences between the two groups. However, Ci decreased during inflation of the tourniquet in both groups, and it significantly decreased in the control group at the time of 5 and 40 minutes after inflation of tourniquet. SVRi significantly increased during inflation of the tourniquet, and decreased immediately after deflation of the tourniquet in the control group. CONCLUSiONS: We concluded that preoperative iV ketamine, 0.25 mg/kg can prevent tourniquet-induced hemodynamic changes in patients under general anesthesia.