The Effects of Acid-Base Imbalance on the Cisatracurium-Induced Neuromuscular Blockade in the Cat / 대한마취과학회지

BACKGROUND: Cisatracurium is a nondepolarizing muscle relaxant. It less likely release histamine and has better cardiovascular stability. It presumably undergoes pH and temperature- dependent, nonenzymatic chemical process, Hofmann reaction. In vitro studies, Hofmann reaction was enhanced with increasing pH, but, in vivo the influence of acid-base imbalance is not well defined. METHODS: To evaluate the effects of acid-base imbalance on the neuromuscular blockade of cisatracurium in the cat, we induced acid-base imbalance and performed cumulative dose-response studies. RESULTS: ED50 of the cisatracurium was significantly reduced in all groups. Dose-response curves from all acid-base imbalance groups did not have significant differences in slopes. But, all showed shift-to-left when compared with control curve, showing decreased ED50. Duration of action was not affected. Recovery index was significantly changed in respiratory and metabolic alkalosis. CONCLUSIONS: It may be concluded that acid-base imbalance significantly augmented the potency of cisatracurium, but, changes of recovery index in this study may be resulted from systemic instability such as unstable hemodynamic state by the prolonged experiment.

Continuous Epidural Analgesia in Labor / 대한마취과학회지

Effects of epidural continuous infusion were compared with those of intermittent injection method in 50 primigravid parturients in active labor. After the intial bolus epidural injection of 0.25% bupivacaine 7-10ml, the parturients were divided randomly assigned to either continuous epidural infusion(INF) group or no infusion control(CONT) group. INF group received continuous epidural infusion of 0.125% bupivacaine 10ml h(-1). The parturients in both groups received intermittent top-ups of 0.25% bupivacaine 5ml with pain above 4 on visual analog scale. Epidural administration of bupivacaine was discontinued at the beginning of second stage of labor. No difference was noted between the two groups compared with respect to pain score during first stage of labor and to duration of epidural analgesia and second stage of labor. The mean pain score during second stage was lower and the general patient satisfaction was greater in INF group. The time interval between top-ups was longer in INF group than in CONT group. The total dose of bupivacaine administered during epidural analgesia was more in INF group than in CONT group. However the difference of hourly dose between two groups when the duration of epidural anagesia exeed four hours was not significant. No parturients in either group experienced severe hypotension, high level of sensory blockade or heavy motor blockade. We conclude that continuous epidural infusion seems capable of keeping parturient's hemodynamics stable during labor, and offers greater satisfaction and safety to the parturients.

Effect of Volume on Hypobaric Spinal Anesthesia for Perianal Surgery with Prone Jacknife Position / 대한마취과학회지

The effect of anesthetic volume on the spread of hypobaric tetracaine were sutdied after intrathecal injection in thirty patients with prone jackknife and 15 degree Trendelenburg position for perinal surgery. The patients were assigned randomly into the one of three groups divided by the 3, 4, or 5 ml of volume of anesthetic solution. The results show that the volume of tetracaine in distilled water with hypobaric spinal anesthesia in prone jackknife and l5 degree Trendelenburg position had a important effect on the anesthetic dermatomal levels in spite of slightly rapid onset with large. volume. Therefore, we concluded that for the perianal surgery in prone jackknife position, as the volume of the anes- thetic solution with hypobaric spinal anesthesia, 3 or 4 ml of the volume are sufficient to get the adequate anesthetic levels.

Overdose with Malfunctional Halothane Vaporizer / 대한마취과학회지

A Vaporizer should deliver a constant concentration of anesthetics under the varying conditions of gas flow, liquid volume, and ambient temperature. We had encountered 3 patients with arrhythmia and ST change on EKG monitoring and cardiovascular collapse which occurred immediately after turning on the halothane vaporizer (Drager Halothan Vapor 19.1 No. 24302). Sudden cardiovascular collapse during the induction of anesthesia in an otherwise healthy patient was suggestive of anesthetic overdose. Thus we checked this vaporizer with the Capnomac Datex and Drager Iris. The inspiratory concentration of the vaporizer was found to be much higher than that of the dial setting. Vaporizers are sensitive, accurate, and scientific instruments which are directly involved in critical life support. All vaporizers should be treated and tested with great care for performance after shipment, any major service repair, or equipment modification.