Effects of Nimodipine on Dose-Response Curves of Vecuronium, Rocuronium, and Atracurium Using Phrenic Nerve-Diaphragm Preparations of Rats / 대한마취과학회지

BACKGROUND: Interactions between nimodipine, a calcium channel blocker, used perioperatively for the treatment of subarachnoid hemorrhage, and vecuronium, rocuronium, and atracurium were studied with phrenic nerve-hemidiaphragm preparations of rats. METHODS: Male 200-300 g Sprague-Dawley rats were randomly allocated into four groups (control, NMD(5), NMD(50) and NMD(500) group, n = 10, respectively) according to the nimodipine concentration, and three groups (control, NMD(2D) and NMD(7D), n = 10, respectively) according to the pretreatment duration. A square wave 0.1 Hz supramaximal stimuli was applied to the phrenic nerve-hemidiaphragm preparation and the twitch height response was recorded with mechanomyography. The dose-response curves were measured, and ED(5), ED(50), ED(90), and ED(95) of each vecuronium, rocuronium, and atracurium in different concentrations of nimodipine of 5, 50, and 500 ng/ml and rocuronium in pretreatment with nimodipine 2.5 mg/kg/d for 2 and 7 days were calculated using an inhibitory sigmoid Emax model. RESULTS: The dose-response curves of rocuronium and atracurium were significantly shifted to the left in NMD(500) group, and significantly shifted to the right in NMD(7D) group (P < 0.05). In NMD(500) group, ED(50), ED(90), and ED(95) of rocuronium and atracurium were significantly reduced, and those of rocuronium in NMD7D group were significantly increased compared with the control group (P < 0.05). CONCLUSIONS: Nimodipine 500 ng/ml in the phrenic nerve-hemidiaphragm preparation of rat increased sensitivity to rocuronium and atracurium, and the dose-response curve was significantly shifted to the left, but following pretreatment for 7 days, nimodipine decreased the potency of rocuronium, and the dose-response curve was significantly shifted to the right.

Effects of Histamine on Nerve Block with Lidocaine / 대한마취과학회지

BACKGROUND: The failure to achieve satisfactory anesthesia following the administration of local anesthetic agents in acute inflammatory tissues is a recognized clinical phenomenon. Many inflammatory mediators can reduce the threshold of nociception during inflammation, and histamine, one of the most important inflammatory mediator, may attenuated local anesthetic effect during inflammation. The purpose of this study was to investigate if histamine can antagonize a lidocaine induced nerve block in vitro. METHODS: Recordings of the compound action potentials (CAP) of A-fiber components were obtained from the isolated sciatic nerves of male Sprague-Dawley rats. The nerve sheath of the sciatic nerve was removed and desheathed nerve was mounted in a recording chamber. Single pulse stimuli (0.5 msec, supramaximal stimuli) were repeatedly applied (2 Hz) to one end of the nerve and CAP recordings were made at the other. The effect of histamine on the suppression of CAP by lidocaine and the effect of histamine on the recovery time to the nerve block by lidocaine were measured. RESULTS: Compared with the baseline amplitude, the amplitudes of CAP were 11.7+/-4.1% for the lidocaine group, 18.3+/-4.6% for the lidocaine histamine 0.05% group, and 26.1+/-5.6% for the lidocaine histamine 0.5% group. Nerve block recovery times were: 38.6+/-3.5 min for the modified Krebs group, 29.8+/-4.2 min for histamine 0.05% in the modified Krebs group, and 19.2+/-1.1 min for histamine 0.5% in the modified Krebs group. CONCLUSIONS: Histamine shortened the recovery time induced by lidocaine. We suggest that histamine may significantly attenuate the effects of local anesthetics in inflammed tissue.

Comparision of the Hemodynamic Effects of Dopamine and Milrinone in Patients Undergoing Off-Pump Coronary Artery Bypass Grafting / 대한마취과학회지

BACKGROUND: Off-pump coronary artery bypass grafting (OPCAB) on the beating heart causes hemodynamic compromise during displacement of the heart for graft anastomosis. To overcome hemodynamic unstability, volume loading, Trendelenburg position, inotropic and vasodilator supports etc. are selected as usual. This study was designed to compare the hemodynamic effects of milrinone and dopamine on OPCAB anesthesia. METHODS: Twenty patients (13 men, 7 women; mean age 63.4 +/- 18.2 years old) who underwent OPCAB were enrolled in this study. The patients were randomly placed in a dopamine group (n = 10) and in a milrinone group (n = 10). Basic doses of each drug was administered during left anterior descending artery (LAD), posterior descending arterty (PDA), and left circumflex artery territory (LCX) anastomosis. Hemodynamic variables such as; heart rate (HR), mean arterial pressure (MAP), mean pulmonary arterial pressure (MPAP), cardiac index (CI), systemic vascular resistance (SVR), pulmonary vascular resistance (PVR), central venous pressure (CVP), and pulmonary capillary wedge pressure (PCWP) were collected before mechanical stabilization (T1), during anastomosis (T2), and 5 minutes after anastomosis (T3) of LAD and LCX in each patient. RESULTS: During LAD anastomosis, HR in the D group increased significantly at T2 (12.6%(upword arrow)) and T3 (9.8%(upword arrow)) but didn't show significant changes in the M group. CI in the M group showed significant increase at T3 (21.7%(upword arrow) compared to T3 and 18.0%(upword arrow) compared to the D group). During LCX anastomosis, HR didn't show significant changes in the M group, MAP in the D group showed significant decrease (19.3%) at T2 but it was insignificant in the M group. MPAP and PVR showed significant increase at T2 in the D group compared to T1 and T2 in the M group. PCWP showed similar changes of PVR during LCX anastomosis CONCLUSIONS: Hemodynamic changes during OPCAB are more remarkable during LCX anastomosis than LAD anastomosis. These changes can be successfully relieved by inotropic supports with continuos milrinone infusion during anastomosis.

Clinical Evaluation of Total Intravenous Anesthesia Using a 3-in-1 Mixture of Propofol, Alfentanil and Atracurium / 대한마취과학회지

BACKGROUND: The use of 3 syringe pumps for one patient has disadvantages. To avoid errors and confusion associated with 3 separate infusions, we conducted a feasibility study of total intravenous anesthesia (TIVA) using a 1 syringe pump to deliver a 3-in-1 mixture containing fixed proportions of propofol, alfentanil and atracurium. METHODS: The 3-in-1 mixture was obtained by mixing 400 mg propofol, 2.5 mg alfentanil, 40 mg atracurium, and totally 80 ml with a 5% dextrose solution. Light microscopy was used to compare emulsion instability of the 3-in-1 with a control mixture. In 40 ASA physical status 1 patients, bolus infusions of 0.5 ml/kg of the 3-in-1 mixture were given for induction of anesthesia. All patients were subsequently intubated and ventilated with an oxygen. Immediately after induction, the maintenance infusion rate was initially set at 2 ml/kg/hr for the first 5 to 10 minutes followed by 1 ml/kg/hr. If inadequate anesthetic depth or muscle relaxation was suspected clinically, a 5 ml bolus of the 3-in-1 mixture (rescue solution) was administered followed by a 10% stepwise increase in the infusion rate. Ten to fifteen minutes before the expected time of completion of surgery, the infusion rate of the 3-in-1 mixture was reduced to 0.5 ml/kg/hr and was stopped at the end of surgery. RESULTS: The 3-in-1 mixtures remained stable for up to 5 hours after preparation. Induction and maintenance of anesthesia were smooth, intubation conditions satisfactory, and intraoperative hemodynamic changes acceptable. Recovery from anesthesia and neuromuscular blockade was rapid. There were no major intra- or immediate postoperative complications. CONCLUSIONS: It may be feasible to provide TIVA using the 3-in-1 mixture for induction and maintenance of anesthesia.

Effects of Aprotinin on Acute Lung Injury by Endotoxin in Rabbits / 대한마취과학회지

BACKGROUND: Aprotinin, a serine protease inhibitor, has an anti-inflammatory and hemostatic effect and has been used to reduce perioperative blood loss and lung injury after cardiopulmonary bypass in cardiac surgery. Acute respiratory distress syndrome (ARDS), which results in clinical manifestations due to non-cardiogenic permeability edema is a fatal condition associated with a mortality rate of 50 to 80%. The purpose of this study was to evaluate the effects of aprotinin on acute lung injury induced by bacterial endotoxin in rabbits. METHODS: Nineteen rabbits were anesthetized with intravenous xylazine, Ketamine and vecuronium and ventilated with a Harvard apparatus maintaining normocapnea. In 7 rabbits, 2 mg/Kg of lipopolysaccharide from E. coli was infused intravenously for 30 min (Toxin group) and in another 7 rabbits aprotonin loading with 200,000 KIU/Kg followed by a continuous infusion of 50,000 KIU/Kg/hr was performed 30 min before the endotoxin infusion throughout the experiment (Aprotinin group). At 1, 2, 3, and 4 hours after endotoxin infusion, arterial blood gas, blood cell count, prothrombin time, activated partial thromboplastin time, fibrinogen, and hemodynamic profiles were checKed. At four hours, the animals were dissected at which time the lungs were divided into three regions for wet/dry weight ratio (WW/DW), myeloperoxidase activity and microscopic examination. RESULTS: In the Aprotinin group, pulmonary vascular resistance, arterial oxygen partial pressure and coagulation function were well preserved compared with the Toxin group. Furthermore, lung WW/DW, myeloperoxidase activity, and inflammatory responses also increased less in the Aprotinin group. CONCLUSIONS: The results of the current data showed that aprotinin has prophylactic effects against acute lung injury and coagulation impairment induced by bacterial endotoxin in rabbits.

Intubating Layngeal Mask Airway in Awake Intubation / 대한마취과학회지

The incidence of difficult intubation varies from 1.5% to 13%, and failed intubation has been identified as one of the anesthesia-related causes of death or permanent brain damage. The Intubating Laryngeal Mask Airway (ILMA) is a new modified laryngeal mask airway with the capability for guided tracheal intubation while maintaining ventilation. The ILMA was designed to improve blind endotracheal intubation through a laryngeal mask airway. It does not require head and neck manipulations on insertion. The success rate of blind intubation using the ILMA was up to 99.3% in patients with or without airway problems. We experienced two cases of the difficult endotracheal intubation due to cervical spine 1 2 fractured 34 years old female patient and cervical spine 5 6 fractured 62 years old female patient were done successful awake airway management through the ILMA with superior laryngeal nerve block with pharyngeal and endotracheal topical spray of lidocaine. These cases suggest that awake tracheal intubations through the ILMA is a safe and useful method for airway management in anesthetic care of cervical spine fracture patients.

Changes in Epidural Pressure during Genernal Anesthesia / 대한마취과학회지

BACKGROUND: Epidural pressure is reported to change in accordance with intracranial pressure (ICP). As ICP changes during general anesthesia, it is also possible that epidural pressure may change during general anesthesia. The aim of this study was to obtain trends of epidural pressure change during general anesthesia. METHODS: Eighteen patients scheduled for gastrectomy were allocated for this study after obtaining informed consent. Epidural catheter was inserted at T7-8, T8-9 interspace before induction. Catheter was connected to a pressure transducer after calibration. General anesthesia was induced with thiopental sodium (5 mg/kg), succinylcholine (1 mg/kg), followed by 3% enflurane. Anesthesia was maintained with 50% N2O in oxygen and 1-2% enflurane with vecuronium (0.1 mg/kg). Each patients was mechanically ventilated with tidal volume of 10 ml/kg at a rate of 10 bpm. Epidural pressure was measured before induction, at the time of injection of thiopental sodium, succinylcholine, laryngoscopy, intubation, surgical incision, and 30 minutes after surgical incision. Stastical analysis was done using repeated measures of ANOVA with Helmert option (p<0.05). RESULTS: Epidural pressure significantly changed dynamically during general anesthesia. Epidural pressures increased at intubation and at 30 minutes after surgical incision when compared with those at the time of laryngoscopy and incision, respectively (p<0.05). CONCLUSION: Our study indicates that epidural pressures changes dynamically during induction period of general anesthesia and also showed possibility that epidural pressure monitoring could be used instead of more invasive direct ICP monitoring.

The Effect of Brain Hypothermia on Brain Edema Formation after Transient Ischemia / 대한구급학회지

BACKGOUND: When ischemia reduces blood supply, hypothermia remains the sine qua non for reducing demand. An alternative to whole body deep hypothermia is an isolated cerebral hypothermia via perfusion of cooled blood through one internal carotid artery. The goal of this study was to evaluate the effect of isolated cold hemisphere perfusion during the cerebral ischemia on the formation of brain edema. METHODS: The studies were designed to perfuse a saline solution into both carotid arteries with a different temperature (left 15degreesC, right 38degreesC) in the same animal. Cerebral ischemia was produced by a combination of the both carotid artery saline perfusion and systemic hypotension to a mean arterial blood pressure of 40 mmHg for 10 minutes. Ninety minutes after reperfusion, brain water contents were measured using the kerosene/bromobenzene density gradient and compared with warm saline perfusion and normal control group. RESULTS: Brain water content of cold saline perfusion hemisphere measured at 90 minutes after ischemia showed decreased water content compared to warm saline perfusion hemisphere (p<0.05). CONCLUSIONS: Cerebral cold saline perfusion during the ischemia decreased the formation of brain edema. These results showed hypothemia is one of the most effective ways to protect brain from the ischemia.