Neuroprotective Effects of Propofol, Ketamine and Propofol-ketamine after Transient Forebrain Ischemia in the Rat / 대한마취과학회지

BACKGROUND: Intravenous anesthetics such as propofol and ketamine have been known to have neuroprotective effects. However, the combination of these drug is not known. This study was conducted to determine the neuroprotective effects of propofol, ketamine or both after transient forebrain ischemia. METHODS: Twenty Sprague-Dawley rats (250-300 gm) were used. Anesthesia was induced with 4% isoflurane in oxygen and then maintained with 1 - 2% isoflurane in oxygen. Ischemic injury was induced by 10 minutes of both common carotid artery ligation and hypotension (MAP < 50 mmHg). All rats were randomly divided into four groups: group I; control group; group II; ketamine 10 mg/kg was administered 10 minutes before injury; group III; propofol (1 mg/kg/min) was administered until EEG isoelectricity; and group IV; ketamine 10 mg/kg and propofol 1 mg/kg/min was administered. The Rectal temperature was maintained at 38oC. After forebrain ischemia, neurologic scores were estimated at 1 hr, 2 hrs, 1 day and 2 days after recovery. The brain was removed 3 days after and stained with H-E stain. RESULTS: Neurologic and histologic scores of group II, III, IV were significantly lower than that of group I. However, there were no significant difference between group II, III and IV. CONCLUSIONS: Ketamine and propofol have neuroprotective effects in transient forebrain ischemia in rats. However, the combination of propofol and ketamine did not show any synergistic or additive effects.

The Two Step Fiberoptic Approach in the Management of a Difficult Pediatric Airway due to a Vallecular Cyst / 대한마취과학회지

A 6-yr-old male weighing 20 kg with the diagnosis of a large vallecular cyst in the oropharynx was scheduled for surgical excision. After a slight loss of consciousness following an IV injection of ketamine 10 mg while maintaining spontaneous respiration, 4% lidocaine was sprayed into the right nostril. An uncuffed 4 mm OD wire-reinforced endotracheal tube was advanced through the right nostril and positioned in the nasopharynx. An ultrathin 60 cm Olympus LF-P fiberoptic bronchoscope (OD: 2.2 mm) was threaded and the vocal cords and surrounding structures were identified as intact. The endotracheal tube and fiberscope were withdrawn. Ketamine 10 mg was injected intravenously again. Following direct insertion of an Olympus fiberoptic bronchoscope (OD: 3.8 mm) through the right nostril without tube placement and visualization of the vocal cords, topical anesthesia of the larynx was achieved by spraying 1 ml 2% lidocaine through the biopsy channel. Thirty seconds later, it was passed into the trachea and 1 ml 2% lidocaine was sprayed intratracheally. The bronchoscope was withdrawn. The 4 mm uncuffed wire-reinforced tube was passed again through the right nostril and an ultrathin fiberoptic bronchoscope (OD: 2.2 mm) was threaded over the tube, and passed smoothly without resistance. There was neither laryngeal spasm nor cough. Anesthesia was maintained with enflurane 2.0 vol%, N2O (1.5 L/min) and O2 (1.5 L/min). The mass was successfully excised and extubated without compromise. The patient was uneventfully discharged the next day.

Comparison of Meperidine and Meperidine with Ketamine for Postoperative Analgesia after Total Abdominal Hysterectomy / 대한마취과학회지

BACKGROUND: The purpose of this study was to compare meperidine and meperidine with ketamine for postoperative analgesia after total abdominal hysterectomy (TAH) and to establish a correlation between three types of pain: pain at rest, pain with movement and pain with coughing (maximal pain). METHODS: This present study compared the quality of pain during pain management in 65 patients undergoing TAH. Patients received i.v. meperidine as the loading dose in the recovery room and PCA with meperidine 600 mg, droperidol 5 mg, normal saline 35 ml for three days (Group 1, n = 36), or with meperidine 600 mg, ketamine 200 mg, droperidol 5 mg, normal saline 16 ml for three days (Group 2, n = 29). Patients were then interviewed on postoperative day 1, 2 and 3 (POD1, 2 and 3) to assess their pain on a visual analogue scale (VAS) of 0 (none) to 10 (worst imaginable) and to compare meperidine and meperidine with ketamine for postoperative analgesia. RESULTS: The mean VAS of pain at rest was 4.5 on POD and decreased to 1.8 on POD 3 for patients receiving meperidine with ketamine was lower than the VAS scores of patients receiving meperidine 5.4 to 2.5. Patients receiving meperidine with ketamine also had less difficulty with side effects, less headache, nausea and vomiting. CONCLUSIONS: IVPCA ketamine in combination with meperidine provides superior postsurgical pain relief, especially at rest and with movement and has fewer side effects than meperidine alone.

The Preemptive Analgesic Effect of Intravenous Ketamine after Lumbar Spine Instrumentation / 대한마취과학회지

BACKGROUND: Well-localized and noxious stimuli are found to produce long-lasting neuronal sensitization. Ketamine is a NMDA receptor antagonist and exerts antinociceptive effects in many pain tests. The aim of this study was to investigate the pre-emptive and analgesic sparing effect of intravenous ketamine in adults aged 30-53 after lumbar spinal instrumentation surgery. METHODS: We compared the effects of preoperative and postoperative intravenous ketamine 0.5 mg/kg on pain after lumbar spinal instrumentation in a double-blind, randomized study in 30 adult patients. After the induction of anesthesia, patients were allocated randomly to receive ketamine intravenously either before (n = 15) or immediately after (n = 15) surgery. Patients were instructed to ask for analgesics whenever they required pain relief and all demands were recorded. Intravenous patient-controlled analgesia (PCA) using butorphanol 16 mg and ketorolac 150 mg was introduced after recovery from general anesthesia. Visual analogue scale (VAS) pain scores were recorded at 1, 2, 3, 4, 5, 6, 9, 12, 24, 36 and 48 hours postoperatively and the total infusion dose of PCA drugs were assessed at 24 hours postoperatively. RESULTS: VAS scores in the preoperative group were significantly lower than in the postoperative group during the first 9 hours after cessation of the operation. The total infusion dose of PCA drugs was significantly lower in the preoperative group (butorphanol 9.1 +/- 0.3 mg, ketorolac 85.3 +/- 2.5 mg) than postoperative group (butorphanol 10.7 +/- 0.2 mg, ketorolac 100.3 +/- 2 mg) (P < 0.05). No serious adverse reactions occurred. CONCLUSIONS: Preoperative intravenous ketamine 0.5 mg/kg in lumbar spinal instrumentation is more effective in reducing postoperative analgesic requirements than it is when given after the operation.

Effect of Continuous Infusion of Low Concentrations of Ketamine on the Bispectral Index and Recovery from Propofol-N2O-O2 Anesthesia / 대한마취과학회지

BACKGROUND: Ketamine as an analgesic adjunct in propofol-based anesthesia has the benefit of potent analgesic action and more stable vital signs due to sympathetic stimulation. However, its impact on the bispectral index and speed of recovery is still controvertial. The aim of this study was to evaluate the effects of continuous infusion of low concentrations of ketamine (0.1 microgram/ml) on the bispectral index and speed of recovery from propofol-N2O-O2 anesthesia. METHODS: Forty ASA I or II adult patients scheduled for elective orthopedic surgery were randomly allocated to one of two groups according to intraoperative ketamine use. In group P, anesthesia was induced and maintained with propofol (Ct: 3 - 6 microgram/ml), 67% nitrous oxide and 33% oxygen and the target concentration of propofol was kept at 4 microgram/ml at least 20 min before the end of propofol infusion. In group P + K, the method of anesthesia was same as in group P, but the low concentration (0.1 microgram/ml) of ketamine was continuously infused until discontinuation of propofol using computer-assisted continuous infusion. Bispectral index, recovery time from anesthesia, current/effect concentration of drugs, vital signs before and at induction, end of drug infusion, eye opening time on verbal command, and orientation time were checked. RESULTS: Changes in vital signs showed no differences between the groups. For bispectral index, there was no difference between groups initially, but it was higher (4 - 8) after the end of drug infusion in group P K than in group P. Also, recovery from anesthesia was delayed significantly in group P + K (P < 0.05). CONCLUSIONS: From these observations, we concluded that the use of low concentrations of ketamine during propofol-N2O-O2 anesthesia increased BIS, delayed eye opening and recovery from anesthesia without any benefit to vital sign stability.

The Effects of Cardiac Bypass Method on the Change of Hemodynamics and Gas Exchange in Fetal Lamb Model under Ketamine Anesthesia / 대한마취과학회지

BACKGROUND: Intrauterine surgical intervention for certain cardiac anomalies may have a therapeutic advantage over postnatal repair or palliation. However, it is essential to establish methods for intrauterine extracorporeal circulation and myocardial preservations which can maintain the hemodynamics and gas exchange in fetal lamb perioperatively. This study was aimed to observe the changes in hemodynamics and gas exchange according to the methods of fetal cardiac bypass. METHODS: Twelve fetal lambs (4.5 5.2 kg) at 120 to 150 days of gestation under ketamine anesthesia were subjected to cardiac bypass for 30 minutes. Six served as a group in which placenta was excluded from the extracorporeal circulation by clamping the umbilical cord during the bypass (the oxygenator group) and in the remaining six, the placenta worked as an in vivo oxygenator (the placenta group). The fetuses were observed every 10 minute during a 30-minute bypass and 30-minute post bypass period. The hemodynamic variables and fetal blood gases were measured at specific intervals. RESULTS: In the oxygenator group, mean arterial pressure (MAP), PaO2, heart rate and bypass flow rate were 62 to 74 mmHg, 220 to 282 mmHg, 169 to 182 /min and 134 to 164 ml/kg/min, respectively during bypass. But rapid deterioration of fetal cardiac and placental gas exchange function was observed following cessation of bypass. In the placenta group, MAP decreased from 61 to 34 mmHg and PaCO2 progressively increased from 56 to 74 mmHg during bypass. Flow rate was suboptimal (74 to 115 ml/kg/min) during bypass. All hearts of the placenta group was fibrillated immediately after discontinuation of bypass. CONCLUSION: The both methods of CPB, use of oxygenator and placenta as gas exchanger, under only ketamine anesthesia did not provide adequate hemodynamics and gas exchange without additional treatment for protection placental reaction. The methods of fetal cardiac bypass using either neonatal membrane oxygenator or placental as an in vivo oxygenator caused severe placental dysfunction and blood gas abnormalities.

Effect of Ketamine Pretreatment on Injection Pain and Hemodynamic Changes during Anesthesia Induction with Propofol / 대한마취과학회지

BACKGROUND: Propofol is useful agents for anesthesia induction and maintenance, but pain on injection and possible hypotension are a commonly encountered problems during induction. Meanwhile, ketamine has potent analgesic and sympathomimetic effect. Therefore, we evaluated the effect of ketamine pretreatment on injection pain and hemodynamic changes during induction with propofol. METHODS: Premedicated one hundred and twenty ASA physical status I or II patients scheduled for elective surgery were randomly allocated into one of four groups (group 1; propofol only, group 2, 3, 4; pretreatment with 25%, 50%, 75% dose of hypnotic ED50 of ketamine, respectively) groups. Intensity and frequency of injection pain, mean arterial pressure and pulse rate were checked for evaluation of ketamine pretreatment on injection pain and hemodynamic changes during induction with propofol. RESULTS: Incidence of pain on injection was significantly reduced in group 2,3 and 4 compared with group 1. Group 2 and 3 showed more stable hemodynamic changes than Group 1 and 4. CONCLUSIONS: 25-50% of hypnotic ED50 of ketamine (0.17-0.33 mg/kg) pretreatment reduced pain on injection and hemodynamic changes during propofol induction significantly.

The Effect of Brimonidine Premedication on the Sympathetic Nervous System during Ketamine Anesthesia in the Ratv / 대한마취과학회지

BACKGROUND: The use of ketamine as the sole anesthetic induces marked central sympathetic stimulation, causing an increase of heart rate and blood pressure. alpha2-receptor agonist has been demonstrated to attenuate many of these undesirable effects when used as a premedicant. Brimonidine is a new and highly selective alpha2-receptor agonist, and rauwolscine is a selective alpha2-receptor antagonist with little affinity for imidazoline receptors. Using power spectral analysis of heart rate variability, this study examines the effect of brimonidine premedication during ketamine anesthesia on the changes in the autonomic nervous system. METHODS: From 57 Sprague-Dawley rats, 12 rats were anesthetized by urethane (U Group, 1.5 g/kg), 18 rats by ketamine (K Group, 100 mg/kg, 2 mg/kg/min continuous infusion) intraperitoneal injection after saline premedication. Brimonidine (BK Group, 30 microgram/kg, n=15), brimonidine with rauwolscine (BRK Group, 30 microgram/kg, 20 mg/kg, n=12) were adminstered as a premedicant before induction of ketamine anesthesia. ECG signals were recorded for 5 min after a period of 10 min of anesthetic stabilization. Power spectal analysis of the data was computed, using short-time Fourier transform. The spectral peaks within each measurement were calculated; a low frequency area (0.04~1.0 Hz), a high frequency area (1.0~5.0 Hz), and a total frequency area (0.04~5.0 Hz) were measured. RESULTS: The results documented that the K Group showed sympathetic activation as compared with the U Group (p<0.001). The BK Group showed sympathetic depression compared with the K and BRK Groups (p<0.001). There were no significant differences in sympatho-vagal balance between the K and BRK Groups. CONCLUSIONS: These results suggest that premedication with brimonidine is effective in attenuating the sympathetic stimulatory effect of ketamine.

Dose Response and Hypnotic Interaction of Propofol and Ketamine for Anesthesia Induction in Korean / 대한마취과학회지

BACKGROUND: Both propofol and ketamine are useful hypnotics for induction of anesthesia, and the combination of propofol and ketamine has been used for total intravenous anesthesia. The aim of this study was to evaluate the dose response of propofol, ketamine and combination of these drug, and determine possible interaction between two drugs in patients. METHODS: The effect of ketamine on the dose response curve for propofol was studied in unpremedicated 165 ASA physical status I or II patients who were scheduled for elective operation. As an endpoint of hypnosis, ability to open eyes on verbal command was checked. Dose response curves for propofol and ketamine were determined with a probit procedure and their type of pharmacologic interaction was determined by fractional and isobolographic analysis. RESULTS: At the hypnotic endpoint, the ED50s were 1.13 mg/kg propofol, 0.66 mg/kg ketamine, and the ED95s were 1.67 mg/kg propofol, 1.09 mg/kg ketamine. The type of interaction between two drugs for hypnosis was found to be additive and ketamine was 1.7 times potent than propofol as an equieffective dose of hypnosis. CONCLUSIONS: The type of interaction between propofol and ketamine for hypnosis was additive.

A Study of iNOS Expression in the Alveolar and NO Concentrations in the Peritoneal Macrophage by Various Anesthetics in the Endotoxemic Rats / 대한마취과학회지

BACKGROUND: It is a well known phenomenon that alveolar and peritoneal macrophages exposed to bacterial lipopolysaccharide (LPS) induce a large output of nitric oxide (NO) and an inducible nitric oxide synthase (iNOS) m-RNA expression. The author elucidate the effects on NO production and iNOS m-RNA expression of various anesthetics, inhalational (halothane, enflurane, sevoflurane) and intravenous (ketamine, propofol), on endotoxemic rats. METHODS: To examine the production of NO in peritoneal macrophages, NO concentrations were measured from the rats following 2 hours exposure to LPS and 2 hours administration of various anesthetics, respectively. Culture supernatants were collected 24 hours after exposure to LPS and anesthetics and assayed by ELISA (Enzyme Linked Immunosorbent Assay) for production of NO. iNOS m-RNA expression was measured using PCR (Polymerase Chain Reaction) techniques and autoradiography. RESULTS: In the control group, the NO concentration was measured at 120 minutes after infusion of LPS to rats, and showed 12+/-4 micrometer. After insufullation of anesthetics to experimental animals, NO concentration increased in the halothane, enflurane, sevoflurane, propofol, and ketamine groups, 132+/-27 (P< 0.05), 49+/-19 (P< 0.05), 23+/-14 (P< 0.05), 37+/-11 (P< 0.05), and 17+/-2 micrometer respectively. The size and brightness of the iNOS m-RNA bands were large in halothane, enflurane, sevoflurane, propofol and ketamine, in order. CONCLUSIONS: Intravenous anesthetics showed more stability than inhalation anesthetics with regand to production of NO and iNOS m-RNA expression in sepsis on rats. The mechanism is not clear, but it is related to the strong stimulating effect to the airway tract in from inhalational anesthetics.

Pre-emptive Analgesia: The Effect of Low-Dose Ketamine on the Postoperative Pain after Circumcision with Unilateral Hydrocelectomy in Children / 대한마취과학회지

Backgrounds: Brief noxious stimuli are found to produce long-lasting neuronal sensitization. This cumulative depolarization results from the activation by glutamate of N-methyl-D-aspartic acid (NMDA) receptor. Ketamine at subanesthetic doses blocks the channel associated with the NMDA receptor. The aim of this study was to investigate the pre-emptive effect of ketamine in children after circumcision with unilateral hydrocelectomy. MATERIALS AND METHODS: We have compared the effect of preoperative ketamine (0.3 mg/kg) in a double-blind, randomized study, which was approved by the local Ethics Committee. Informed consents were obtained from their parents. After induction of anesthesia, patients were allocated randomly to receive a ketamine (n=20) or placebo (n=20) intravenously before surgery. Postoperative pain was rated on a faces scale for the first 24 hours. If pain occurred, children received tiaprofenic acid in a dose related to body weight. The cumulative pain score, the time of the first requirement of analgesics, and total requirement of analgesics for 24 hours were also checked. RESULTS: The pain scores at 4, 5, 6, 7, 8, 9, and 12 hours after operation were significantly low in ketamine group. The cumulative pain scores for the first 8 hours and the total requirements of analgesics were significantly low in ketamine group. The time of the first requirement of analgesic was significantly delayed in ketamine group. CONCLUSIONS: Preoperative ketamine in the pediatric circumcision with unilateral hydrocelectomy is effective on the reducing the intensity of the postoperative pain. The results of this study support the theory of pre-emptive analgesia of ketamine.

The Preemptive Analgesic Effect of Intravenous Ketamine / 대한마취과학회지

BACKGROUND: Preemptive treatment with ketamine, a noncompetitive NMDA antagonist, may prevent establishment of postoperative hypersensitivity by blocking the sensory input that induces the central sensitization. The aim of this study was to determine if continuous preemptive administration of intravenous (IV) ketamine decreases postoperative pain. METHODS: Sixty healthy informed patients scheduled for elective abdominal hysterectomy were randomly divided into two groups of equal size and studied in a double-blind manner. Before surgical incision, patients were given 1 mg/kg of ketamine or equal volume of saline followed by IV infusion of 0.01 mg/kg/min, which was discontinued at peritoneal closure. IV morphine patient-controlled analgesia (PCA) was started in all patients at peritoneal closure. Visual analogue scale (VAS) pain scores and total morphine consumption were recorded at 1, 3, 6, 9, 12, 24, 36, and 48 hours postoperatively. RESULTS: VAS pain scores at rest were significantly less in the ketamine group than in the saline group at 1, 3, 24, 36, and 48 hr postoperatively. VAS at moving status were less in the ketamine group at 1, 3, 12, 24, 36, 48 hr postoperatively. Patients in the ketamine group had significantly lower morphine consumption throughout the study period, about 20-50% reduction in postoperative total morphine was observed. Only ketamine group experienced severe headache (10 cases), while there were no intergroup differences in other side effects such as pruritus, bad dream, and backache. CONCLUSION: These results suggest that preemptive continuous IV ketamine decreases postoperative pain intensity and IV morphine requirement, and its action lasts longer than the normal expected duration of action of ketamine.

Effect of Ketamine or Sodium Thiopental on the Venous Capacitance in Dog / 대한마취과학회지

BACKGROUND: A small change in venous capacitance significantly alters venous return and thus cardiac output. It is therefore important to know the effects of intravenous anesthetics on venous capacitance, particularly in a hypovolemic state. As ketamine does not suppress sympathetic activity, it has been suggested that ketamine may be the drug of choice for anesthesia during hypovolemia. The purpose of this study was to examine the effects of ketamine or sodium thiopental on venous capacitance and total vascular compliance in dogs. METHODS: Twenty mongrel dogs, weighing 10~15 Kg, were divided into two group (ketamine group: 10, sodium thiopental group: 10) of 10 each. Venous capacitance was assessed before and after drug (ketamine 1 mg/kg or sodium thiopental 5 mg/kg) injection by measuring mean circulatory filling pressure (MCFP) in the normovolemia and hypovolemia. MCFP was measured after arresting the circulation by tightening of superior vena cava and inferior vena cava snares simultaneously. RESULTS: As compared with MCFP in the normovolemia and hypovolemia, MCFP was significantly increased by ketamine in the normovolemia and hypovolemia. As compared with MCFP in the hypovolemia, MCFP was significantly decreased by sodium thiopental in the hypovolemia. The slope of the regression line relating MCFP and blood volume was not significantly altered by ketamine or sodium thiopental, which suggests that ketamine or sodium thiopental did not alter total vascular compliance. CONCLUSIONS: These results suggest that ketamine decreases venous capacitance in the normovolemia and hypovolemia but sodium thiopental increases venous capacitance in the hypovolemia.

Spectral Analysis of Heart Rate and Blood Pressure Variability during Hemorrhage in Ketamine-Anesthetized Rats / 대한마취과학회지

BACKGROUND: This study was aimed to elucidate the effect of ketamine anesthesia on circulatory response to hemorrhage in rats by power spectral analysis of heart rate and blood pressure variability. METHODS: Nineteen male Sprague-Dawley rats weighing 290~475 g were divided into ketamine (100 mg/kg, im)-anesthetized(K, n=10) and conscious(C, n=9) groups. Hemorrhage was induced with a withdrawal pump from the femoral artery at 3 ml/kg/min for 5 min. Arterial pressure was measured with a pressure transducer connected to the contralateral femoral artery for 5 min before, during and after hemorrhage. The blood pressure signal digitized at 500 Hz through a data acquisition system was analyzed with fast Fourier transform algorithm to yield power spectra of sytolic(SP) and diastolic(DP) blood pressure and instantaneous heart rate(HR). Powers of very low frequency(VLF, 0.02~0.26 Hz), low frequency (LF, 0.26~0.75 Hz) and high frequency(HF, 0.75~5.00 Hz) band were expressed as percent of total power. RESULTS: Before hemorrhage blood pressure was higher in K(152.4+/-3.7/99.9+/-4.9 mmHg) than in C(143.3+/-5.7/95.5+/-4.1 mmHg) rats, but was changed by hemorrhage in both groups. Before hemorrhage HR in K and C rats were 361.4+/-17.5 and 363.4+/-18.5 beats/min . HR were significantly increased to 403.2+/-20.3 and 396.2+/-18.9 beats/min during and after hemorrhage in K rats, and increased to 409.1+/-20.9 beats/min during hemorrhage in C rats. Before hemorrhage total powers of blood pressure and HR variability were higher in K than in C rats. During hemorrhage, total powers of blood pressure and heart rate variability tended to increase in both groups. Before hemorrhage, percent powers of systolic pressure variability of HF and VLF were higher in K than in C rats and LF was lower in K than in C rats. During hemorrhage, K group showed no significant changes but C group showed significant changes. Before hemorrhage, percent powers of diastolic pressure variability of VLF was higher in Kthan in C rats, and HF and LF were lower in K than in C rats. During and after hemorrhage, K group showed no significant changes, but C group showed significant decrease in LF and increase in VLF. Before hemorrhage, percent powers of heart rate variability of K rats showed higher HF and VLF, and lower LF than C rats. During and after hemorrhage HF and VLF of both groups showed no significant changes except significant increase in VLF after hemorrhage in C rats, but LF of both groups showed significant decrease. CONCLUSIONS: It was concluded that autonomic activity, especially cardiac sympathetic activity, was increased in response to hemorrhage in K rats. Ketamine anesthesia stimulated overall autonomic activity, especially sympathetic activity and vasomotor tone. In C rats hormonal factor contributed to blood pressure and heart rate variability during hemorrhage.

Comparison of Midazolam-Ketamine with Midazolam for Sedation during Retrobulbar Block in Cataract Surgery / 대한마취과학회지

BACKGROUND: Many ophthalmic procedures can be performed using a retrobulbar regional anesthetic technique. However, retrobulbar block is painful and most of patients express anxiety about the procedure. In addition, several life-threatening complications may occur. We compared the effects of midazolam and midazolam-ketamine as a sedative during retrobulbar block in cataract surgery. METHODS: Thirty patients undergoing cataract surgery were randomly allocated into two groups, group I (n=15) was received midazolam and group II (n=15), midazolam-ketamine. Mean arterial pressure (MAP), heart rate (HR), and peripheral oxygen saturation (SpO2) were compared before administration of drugs and 1, 2, 3, 4, 5, 10, 20, and 30 min after administration of drugs. Patients' movement requiring restraint were also checked. In the recovery room, postoperative nausea and vomiting, recall, delirium and/or hallucinations, and ocular complications were recorded. RESULTS: There were no significant differences in MAP and SpO2 between groups but heart rates were significantly increased at 1, 2, 3, 4, and 5 min than baseline in group II. Movement score was significantly lower in Group II than in Group I during the block (p<0.05). Recall during performance of the nerve block occured more often in Group I than in Group II (p<0.05). CONCLUSION: Low-dose midazolam-ketamine sedation sequence was superior to a midazolam technique regarding patients' movement and recall.

The Effects of the Combination of Ketamine and Midazolam for Sedation during Epidural Anesthesia / 대한마취과학회지

BACKGROUND: Epidural anesthesia is becoming an increasingly important aspect of anaesthetic practice because it has many advantages. To achieve the appropriate sedation, various methods have been described. The authors applied the ketamine for this purpose in subanesthetic dose and compared with the midazolam that has been most commonly used for intravenous sedation. METHODS: Fifty-seven adult patients undergoing lower abdominal and extremity surgery who were receiving epidural anesthesia were randomely enrolled into this clinical study. They were allocated to three groups to receive only normal saline (group C), midazolam 0.05 mg/kg (group M) and ketamine 0.5 mg/kg midazolam 0.05 mg/kg (group K) in normal saline 10ml, respectively. Hemodynamic and respiratory measurements were recorded at baseline, 1 minute, 3 minute, 5 minute, 10 minute, 20 minute and 30 minute after sedation. The degree of sedation was assessed by a blinded observer using sedation score. RESULTS: There were no significant differences for hemodynamic and respiratory parameters, but decrements of arterial pressure at 1 minute after sedation were most remarkable in the group M. Sedation was satisfactorily achieved by combination of ketamine and midazolam without significant emergence reaction. CONCLUSIONS: The combination of ketamine and midazolam was judged to be suitable alternative for sedation during epidural anesthesia.

The Effects of Ketamine on Hemodynamics and Intracranial Pressure during O2-N2O-Isoflurane Anesthesia in Rabbits / 대한마취과학회지

BACKGROUND: The potential adverse effects of ketamine in neurosurgical anesthesia have been well established. However, the effects of ketamine on intracranial pressure (ICP) and hemodynamics during general anesthesia remain unclear. The purpose of this study was to assess the effects of ketamine on hemodynamics and ICP in anesthetized, ventilated rabbits. METHODS: Thirty rabbits were divided into three groups: Group 1 (n=10) received 1 ml/kg normal saline iv; Group 2 (n=10) received 0.5 mg/kg ketamine iv; Group 3 (n=10) received 1.0 mg/kg ketamine iv. After induction with thiopental, anesthesia was maintained with isoflurane and nitrous oxide in oxygen. During controlled ventilation, ICP, mean arterial pressure (MAP), cerebral perfusion pressure (CPP) and heart rate (HR) were measured. The ICP was measured using Ladd ICP monitoring system. All variables were evaluated at baseline and for 30 min following ketamine. RESULTS: In group 1, ICP, MAP, CPP and HR were unchanged over the course of the study. In group 2, ICP, MAP and CPP were unchanged. HR increased at 1, 3 and 5 min (p<0.01), 10 and 20 min (p<0.05) after injection. In group 3, ICP, MAP and CPP increased at 1 and 3 min (p<0.01) after injection. HR increased at 1, 3 and 10 min (p<0.01), 5 min (p<0.05) after injection. CONCLUSIONS: These results suggest that 0.5 and 1.0 mg/kg of ketamine don't significantly affect the hemodynamics and ICP in anesthetized, mechanically ventilated rabbits.

Regulation of Astroglial Volume by Ketamine in Glutamate Induced Cellular Volume Changes / 대한마취과학회지

BACKGROUND: Relative changes of astroglial volume constitute the major part of brain edema, which is related to delayed neuronal damage. Several factors including glutamate may contribute to astroglial swelling. Intravenous anesthetic, ketamine was known to restore neuronal damage by inhibiting NMDA receptor activity. Therefore, we decided to investigate the effect of ketamine on the astrocyte swelling by glutamate in the present study. METHODS: To analyze cell swelling in vitro, glial cell line, U1242MG was used. The effects of glutamate (1, 2, 3 mM), and glutamate with ketamine (1 mM) on the regulation of astrocyte volume were achieved by flow cytometry system. To eliminate the dead cells from experimental cell suspension and to assess cell viability, fluorescent dye propidium iodide was used. RESULTS: Glutamate addition (1, 2, 3mM) caused astroglial swelling both in calcium present and calcium absent buffer. The difference of cellular swelling dependent on glutamate concentration was only seen in calcium free buffer (p<0.05). Ketamine per se did not affect astroglial volume. However, when it was added to glutamate perfusion, 1 mM ketamine diminished cellular swelling by glutamate during first 10 minutes (p<0.05), and cellular shrinkage by glutamate after 1 hour incubation (p<0.05). CONCLUSIONS: Ketamine (1 mM) is effective in the regulation of astroglial volume alterations induced by glutamate in both short time and long time perfusion.

A Comparison of Inhalation Anesthesia with Enflurane and Intravenous Anesthesia with Ketamine Hydrochloride in Lung Surgery of Patients with Decreased Pulmonary Function / 대한마취과학회지

BACKGROUND: Serious pulmonary complications after lung surgery increase morbidity and mortality in perioperative period. Ketamine hydrochloride produces strong analgesic effect in spite of the psychomimetic effects. Intravenous anesthesia with ketamine was performed in lung surgery of patients with decreased pulmonary function and compared with inhalation anesthesia with enflurane. METHODS: Sixty patients, scheduled for elective lung surgery, were randomly assigned to two groups. Patients received either enflurane (Group 1, n=30) or ketamine (Group 2, n=30) as main anesthetic drug. Blood pressure and heart rate were compared in preinduction, postinduction, postintubation, postincision, intraoperative period (30 minutes, 60 minutes) and recovery room between groups, and in each group. Arterial blood gas analysis was compared in preoperative period, intraoperative period and recovery room between groups. Postoperative psychological complications evaluated in group 2. RESULTS: Blood pressure and heart rate were significantly different in postinduction, postintubation and recovery room between groups. PaO2 in group 2 was higher than in group 1 during intraoperative period and recovery room. Postoperative psychological complications occured in 4 patients (13%) in group 2. CONCLUSIONS: Ketamine affords advantage over enflurane anesthesia in terms of PaO2 during intraoperative period and recovery room in lung surgery of patients with decreased pulmonary function.