Comparison of Postoperative Complications, Postoperative Pain and Satisfaction between Spinal Anesthesia and Monitored Anesthetic Care under Total Intravenous Anesthesia for an Arthroscopy / 대한마취과학회지

BACKGROUND: Whether monitored anesthetic care (MAC) under total intravenous anesthesia can substitute for spinal anesthesia in knee arthroscopic surgery in regard to frequency of postoperative complications, degree of postoperative pain and degree of the satisfaction of patients and operator was investigated. METHODS: Sixty healthy patients were allocated randomly into a spinal group (n = 30) who received spinal anesthesia and an MAC group (n = 30) who received TIVA for anesthesia for arthroscopic surgery. All patients were NPO for 8 hours before surgery were premedicated and monitored with an EKG, noninvasive blood pressure and pulse oximeter. Heavy 0.5% bupivacaine, 10 - 12 mg, was used for spinal anesthesia and fentanyl 2ng/kg, propofol 1 mg/kg, ketamine 0.3 mg/ kg, and ketorolac 30 mg were given intravenously for induction and propofol was maintained at 3 - 4 mg/kg/h for TIVA. Local anesthetics infiltration was done at the arthroscopic portal site and fentanyl 25ng and propofol 20 mg were added intermittently. Postoperative complication (nausea, vomitting, back pain, dizziness, pain or voiding difficulty) and satisfaction of the patients and surgeon were investigated by VAS and 5 grade methods, respectively. RESULTS: The frequency and degree of back pain, pain at the operative site and voiding difficulty occured less and the VAS was decreased in the MAC group while in the recovery room, 6 hours and the day after the operation. The grade of satisfaction of the patients and that of the surgeon were also high in the MAC group. CONCLUSIONS: These results show that, if careful airway management is provided, MAC under TIVA is a more useful anesthetic method than spinal anesthesia in an arthroscopy.

Influence of Calcium Concentration on the Neuromuscular Effects of Vecuronium on the Hemidiaphragm-Phrenic Nerve of Rats / 대한마취과학회지

BACKGROUND: Calcium disturbance may clinically produce diaphragmatic weakness. Extracellular calcium is necessary for diaphragmatic contraction, suggesting that the diaphragm behaves more like cardiac muscle. The effect of extracellular Ca2 concentrations on the relaxation action of vecuronium was studied in rat hemidiaphragm-phrenic nerve preparations. METHODS: Hemidiaphragm-phrenic nerve preparations were obtained from male Sprague-Dawley rats (200 300 g). Preparations were bathed in Kreb's solution of (mM): NaCl 118, KCl 5, CaCl2 2.5, NaHCO3 30, KH2PO4 1, MgCl2 1 and glucose 11, then maitained at 37oC when aspirated with a mixture of 95% O2 and 5% CO2. Isometric forces generated in response to 0.1 Hz, 2 Hz for 2 seconds and, 50 Hz for 2 seconds with supramaximal electrical stimulation (0.2 msec, rectangular) to the phrenic nerve, were measured with a force transducer. Single twitch tension and peak tetanic tension were calculated as a percentage of control. TOF fade was calculated as (1-(T4/T1))x100. Each preparation was exposed to the alterations in calcium concentrations of the Kreb's solution (3.75, 3.125, 1.5, 1.25, 0.625, 0.3125 (mM)), and the adequate volume of vecuronium stock solution was added to the tissue bath for desired bath concentration. The effects of calcium and vecuronium were allowed to reach a steady state before measurement of tension parameters was done. Single twitch tensions or peak tetanic tensions, which were measured at each calcium concentration, were compared respectively. EC5, EC25, EC50, EC75, and EC95 of vecuronium for a single twitch tension, TOF fade, and peak tetanic tension at each calcium concentration, were calculated using a sigmoid Emax model. We compared the EC50 of vecuronium according to calcium concentrations. Data was compared by the Kruskal-Wallis test with a post hoc Wilcoxon rank sum test. A p-value of below 0.05 was considered significant. RESULTS: The range of calcium concentration studied didn't produce differences among single or tetanictensions respectively. The EC50's of vecuronium decreased as calcium concentration decreased. CONCLUSIONS: The reduction of calcium concentration can augment the action of vecuronium on the diaphragm.

Clinical Evaluation of Low-Flow Enflurane Anesthesia in Infants / 대한마취과학회지

BACKGROUND: The purpose of this study was to evaluate the safety and efficacy of low-flow anesthesia with a semi-closed circle anesthesia system in infants. METHODS: Twenty, ASA physical status 1 or 2, infants were randomly assigned into two groups: high-flow anesthesia (HFA) or low-flow anesthesia (LFA). An identical semi-closed Dr ger circle anesthesia system (Cato) was used to all patients. Initial fresh gas flow (FGF) was N2O 1.5 L/min and O2 1.5 L/min in both groups. This FGF of 3 L/min was maintained in the HFA group. After 10 min of HFA, the FGF was reduced to 500 ml/min (N2O 250 ml/min and O2 250 ml/min) in the LFA group. RESULTS: Hypoxic or hypercarbic gas concentrations were not observed in all patients. Enflurane consumption during LFA was about 1/3 of that during HFA (6.8 +/- 1.3 ml vs. 19.5 +/- 5.8 ml). The mean highest esophageal temperature was similar in both groups. The mean highest inspiratory gas and soda lime temperatures were significantly higher in the LFA group than in the HFA group. CONCLUSIONS: Low-flow anesthesia in a circle system with a fresh gas flow of N2O 250 ml/min and O2 250 ml/min could be performed safely and economically for infants.