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Biomedical subjects

H Koinig

Publications and source records attributed to H Koinig.

At least 19 recordsLinked to original sources
PubMed2003

[The choice of drugs for caudal anaesthesia in children. An overview].

Caudal anaesthesia is the most frequently used regional technique in paediatric anaesthesia. Caudal in combination with general anaesthesia is usually performed in healthy children (i.e. for herniotomy or hypospadias). Therefore every complication of this method is a catastrophe, even when the incidence of these complications is very low. Some of the documented complications of caudal anaesthesia in children are caused by the local anaesthetic solutions and/or by additives. Thus, the choice of substances for paediatric caudal blocks should minimize the risk associated with the substances used for this indication. Over the last decades the standard was bupivacaine but because of serious cardiovascular and central-nervous toxicity following inadvertent intravascular injection of bupivacaine during caudal puncture, the less toxic ropivacaine should be favoured for this indication. A huge number of clinical studies have proven the clinical effectiveness and safety of ropivacaine also for this indication. In addition, levobupivacaine, the L-enantiomere of bupivacaine, will also be an interesting local anaesthetic in the future for paediatric caudal anaesthesia. By using additives to local anaesthetics better analgesic properties should be obtained. Following an exact review of the literature, only clonidine and S(+)-ketamine are useful additives to local anaesthetics in paediatric caudal anaesthesia.

Anesthesia, Caudal↗
PubMed2001

Lubeluzole inhibits accumulation of extracellular glutamate in the hippocampus during transient global cerebral ischemia.

Increases in extracellular glutamate during cerebral ischemia may play an important role in neuronal injury. Lubeluzole is a novel neuroprotective drug, which in previous in vitro and focal ischemia studies has been shown to inhibit nitric oxide synthesis, to block voltage-gated Na+-ion channels, and to inhibit glutamate release. In this study, we investigated the ability of lubeluzole to inhibit glutamate accumulation during episodes of transient global cerebral ischemia. Twenty-five New Zealand white rabbits were randomized to one of four groups: a normothermic control group; a hypothermic group; a 1.25 mg/kg lubeluzole group; or a 2.5 mg/kg lubeluzole group. The animals were anesthetized, intubated, and ventilated before microdialysis probes were placed in the hippocampus. Lubeluzole was given intravenously 90 min before the onset of ischemia. Esophageal temperature was maintained at 38 degrees C in the control, and lubeluzole treated groups, while the animals in the hypothermia group were cooled to 30 degrees C. A 15-min period of global cerebral ischemia was produced by inflating a neck tourniquet. Glutamate concentrations in the microdialysate were determined using high-performance liquid chromatography (HPLC). During ischemia and early reperfusion, glutamate concentrations increased significantly in the control group and returned to baseline after 15 min of reperfusion. In the lubleuzole 2.5 mg/kg and hypothermia groups, glutamate levels were significantly lower (P<0.05) than in the control group and there was no significant change from baseline levels during the entire experiment. This study suggests that lubeluzole is effective in inhibiting extracellular glutamate accumulation during global cerebral ischemia, and has the potential to produce potent neuroprotection when instituted prior to an ischemic event.

Action Potentials↗
PubMed2001

Clonidine as adjuvant for mepivacaine, ropivacaine and bupivacaine in axillary, perivascular brachial plexus block.

PURPOSE: To evaluate the effects of clonidine on three local anesthetics (mepivacaine 1%, ropivacaine 0.75% and bupivacaine 0.5%) with comparable potency and almost the same concentration-response relationship. METHODS: One hundred and twenty trauma-patients were randomly allocated into six groups. In the control-groups (Mo/Ro/Bo) brachial plexus was performed using 40 mL of local anesthetic plus 1 mL of NaCL 0.9%. In the clonidine-groups (Mc/Rc/Bc) brachial plexus was performed using each 40 mL of drug plus 1 mL (0.150 mg) of clonidine. Onset-time and the duration of the sensory block were recorded. Data are expressed as mean +/- SD. RESULTS: According to the average sensory block determined by a visual analog scale in the median, ulnar and radial nerve distributions and ranging from 100 (no sensory blockade) to 0 (complete sensory blockade), both mepi-groups showed a rapid onset (at 10 min: -Mo 20 +/- 15/Mc 19 +/- 14; at 30 min: -Mo 3 +/- 4/Mc 5 +/- 4). The ropi-and bupi- groups both had a longer onset time (at 10 min: -Ro 23 +/- 19/Rc 25 +/- 22/Bo 24 +/- 15; at 30 min -Ro 10 +/- 6/ Rc 11 +/- 6 /Bo 12 +/- 4). The onset time in group-Bc was significantly prolonged (at 10 min: -45 +/- 21; at 30 min: -20 +/- 6). Duration of motor blockade was prolonged by clonidine only in the mepivacaine and bupivacaine groups; (in minutes: Mo 212 +/- 47 -Mc 468 +/- 62; Ro 702 +/- 52 -Rc 712 +/- 82; Bo 728 +/- 36 -Bc 972 +/- 72). CONCLUSION: The present study shows that the addition of clonidine has a different impact on each of the three local anesthetics investigated in terms of onset and duration of block.

Adjuvants, Anesthesia↗
PubMed2001

The combination of lamotrigine and mild hypothermia prevents ischemia-induced increase in hippocampal glutamate.

The excessive release of glutamate during cerebral ischemia may play an important role in subsequent neuronal injury. Both lamotrigine and hypothermia have independently been shown to attenuate the release of glutamate. In this study, the authors sought to determine whether these effects were additive. Thirty-five New Zealand White rabbits were randomized to one of six groups: a normothermic control group; a lamotrigine-treated group; two hypothermic groups at 33 degreesC or 34.5 degreesC; or two groups treated with both hypothermia at 33 degreesC or 34.5 degreesC plus lamotrigine. Animals were anesthetized before implanting microdialysis probes in the hippocampus. Esophageal temperature was maintained at 38 degreesC in the control and lamotrigine groups, while the temperatures of animals in the hypothermia and hypothermia-plus-lamotrigine groups were cooled to 33 degreesC or 34.5 degreesC. Two 10 minute periods of global cerebral ischemia were produced by inflating a neck tourniquet. Levels of glutamate in the microdialysate were then determined using high-performance liquid chromatography. Extracellular glutamate concentrations increased only slightly from baseline during the first ischemic period. Glutamate levels during the second ischemic episode in the hypothermia-plus-lamotrigine group (34.5 degreesC) were significantly lower than those in the hypothermia group alone (34.5 degreesC), lamotrigine, or control groups (P < .01). The fact that mild hypothermia (34.5 degreesC) plus lamotrigine (20 mg/kg) together were more effective in inhibiting extracellular glutamate accumulation than hypothermia (34.5 degreesC) or lamotrigine (20 mg/kg) alone, suggests the potential for increased neuroprotection by the addition of lamotrigine to mild hypothermia.

Animals↗
PubMed2000

Effect of a neuronal sodium channel blocker on magnetic resonance derived indices of brain water content during global cerebral ischemia.

Diffusion-weighted magnetic resonance imaging (DWI) with calculation of the apparent diffusion coefficient (ADC) of water is a widely used noninvasive method to measure movement of water from the extracellular to the intracellular compartment during cerebral ischemia. Lamotrigine, a neuronal Na(+) channel blocker, has been shown to attenuate the increase in extracellular concentrations of excitatory amino acids (EAA) during ischemia and to improve neurological and histological outcome. Because of its proven ability to reduce EAA levels during ischemia, lamotrigine should also minimize excitotoxic-induced increases in intracellular water content and therefore attenuate changes in the ADC. In this study, we sought to determine the effect of lamotrigine on intra- and extracellular water shifts during transient global cerebral ischemia. Fifteen New Zealand white rabbits were anesthetized and randomized to one of three groups: a control group, a lamotrigine-treated group, or a sham group. After being positioned in the bore of the magnet, a 12-min 50-s period of global cerebral ischemia was induced by inflating a neck tourniquet. During ischemia and early reperfusion there was a similar and significant decrease of the ADC in both the lamotrigine and control group. The ADC in the sham ischemia group remained at baseline throughout the experiment. Lamotrigine-mediated blockade of voltage-gated sodium channels did not prevent the intracellular movement of water during 12 min 50 s of global ischemia, as measured by the ADC, suggesting that the ADC decline may not be mediated by voltage-gated sodium influx and glutamate release.

Animals↗
PubMed2000

The effects of clonidine on ropivacaine 0.75% in axillary perivascular brachial plexus block.

INTRODUCTION: The new long-acting local anesthetic ropivacaine is a chemical congener of bupivacaine and mepivacaine. The admixture of clonidine to local anesthetics in peripheral nerve block has been reported to result in a prolonged block. The aim of the present study was to evaluate the effects of clonidine added to ropivacaine on onset, duration and quality of brachial plexus block. METHODS: Patients were randomly allocated into two groups. In group I brachial plexus was performed using 40 ml of ropivacaine 0.75% plus 1 ml of NaCL 0.9%, and in group II brachial plexus was performed using 40 ml of ropivacaine 0.75% plus 1 ml (0.150 mg) of clonidine. Onset of sensory and motor block of radial, ulnar, median and musculocutaneous nerve were recorded. Motor block was evaluated by quantification of muscle force, according to a rating scale from 6 (normal contraction force) to 0 (complete paralysis). Sensory block was evaluated by testing response to a pinprick in the associated innervation areas. Finally, the duration of the sensory block was registered. Data were expressed in mean+/-SD. For statistical analysis a Student t-test was used. A P-value of < or = 0.05 was considered as statistically significant. RESULTS: The duration of blockade was without significant difference between the groups. Group I: 718+/-90 min; Group II: 727+/-117 min. There was no intergroup difference in sensory and motor onset or in quality of blockade. CONCLUSION: The addition of clonidine to ropivacaine 0.75% does not lead to any advantage of block of the brachial plexus when compared with pure ropivacaine 0.75%.

Adult↗
PubMed2000

S(+)-ketamine for caudal block in paediatric anaesthesia.

We have evaluated the intra- and postoperative analgesic efficacy of preservative-free S(+)-ketamine compared with bupivacaine for caudal block in paediatric hernia repair. After induction of general anaesthesia, 49 children undergoing hernia repair were given a caudal injection (0.75 ml kg-1) of S(+)-ketamine 0.5 mg kg-1 (group K1), S(+)-ketamine 1.0 mg kg-1 (group K2) or 0.25% bupivacaine with epinephrine 1:200,000 (group B). No additional analgesic drugs were required during operation in any of the groups. Haemodynamic and respiratory variables remained stable during the observation period. Mean duration of analgesia was significantly longer in groups B and K2 compared with group K1 (300 (SD 96) min and 273 (123) min vs 203 (117) min; P < 0.05). Groups B and K2 required less analgesics in the postoperative period compared with group K1 (30% and 33% vs 72%; P < 0.05). Postoperative sedation scores were comparable between the three groups. We conclude that S(+)-ketamine 1.0 mg kg-1 for caudal block in children produced surgical and postoperative analgesia equivalent to that of bupivacaine.

Anesthesia, Caudal↗
PubMed2000

Analgesic effects of caudal and intramuscular S(+)-ketamine in children.

BACKGROUND: Previous studies suggest that caudal administration of ketamine cause effective analgesia. The purpose of the current study was to compare the clinical effectiveness and plasma concentrations of S(+)-ketamine after caudal or intramuscular administration in children to distinguish between local and systemic analgesia. METHODS: After induction of general anesthesia, 42 patients, aged 1 to 7 yr, scheduled to undergo inguinal hernia repair randomly received a caudal (caudal group) or intramuscular (intramuscular group) injection of 1 mg/kg S(+)-ketamine. Intraoperatively, heart rate (HR), mean arterial pressure (MAP) and arterial oxygen saturation were measured. Postoperative measurements included duration of analgesia, a four-point sedation score, and hemodynamic and respiratory monitoring for 6 h in the recovery room. Analgesic requirements in the recovery room were assessed by an independent blinded observer using an observational pain/discomfort scale (OPS). Plasma samples for determination of ketamine concentrations were obtained before and 10, 20, 30, 45, 60, 90, 120, and 180 min after injection of S(+)-ketamine. RESULTS: A significantly longer duration of analgesia (P < 0.001) was observed after caudal administration (528 min [220-1,440 min]; median [range]) when compared with intramuscular administration (108 min [62-1,440 min]) of S(+)-ketamine. Plasma levels of ketamine were significantly lower from 10 to 45 min after caudal administration than after intramuscular injection. CONCLUSION: Caudal S(+)-ketamine provides good intra- and postoperative analgesia in children. Despite similar plasma concentrations during most of the postoperative observation period, caudal S(+)-ketamine provided more effective analgesia than did intramuscular S(+)-ketamine, indicating a local analgesic effect.

Absorption↗
PubMed1999

Occupational exposure to sevoflurane during sedation of adult patients.

OBJECTIVES: In a field study we evaluated the workplace pollution occurring during conscious sedation with sevoflurane in adults. METHODS: Sevoflurane was given in 100% oxygen at a fresh gas flow rate of 3 l/min via a nasal mask. This was conducted in 25 patients scheduled for surgical procedures performed under regional anesthesia. Trace concentrations of sevoflurane were directly measured every minute in the breathing zone by means of a photoacoustic infrared spectrometer in an operating room with an air turnover of 20 changes/h. RESULTS: The mean sedation time was 49.6+/-20.4 min. The average vaporizer setting of the anesthesia machine was 1.63+/-0.6 vol%, resulting in a patient's mean end-tidal sevoflurane concentration of 0.78+/-0.2 vol%. The 8-h time-weighted average was calculated to be 0.58 ppm sevoflurane. CONCLUSIONS: The trace gas concentrations were low and comparable with values obtained under inhalation induction in adults and children. Although no occupational standard for sevoflurane is currently defined, the measured values are clearly under the standards recommended for enflurane (20 ppm) and isoflurane (10 ppm) by the European health authorities. We conclude that the new anesthesiologic method of conscious sedation with sevoflurane in adults using a nasal mask would not result in a violation of occupational standards, provided that the future value set for sevoflurane would be similar to those recommended for isoflurane or enflurane.

Adult↗
PubMed1999

The dose-response of caudal ropivacaine in children.

BACKGROUND: Ropivacaine, a new local anesthetic, is less cardiotoxic in adults and is less likely to cause motor blockade than is bupivacaine. The authors evaluated the clinical effectiveness and hemodynamic effects of ropivacaine compared with bupivacaine and the pharmacokinetics of ropivacaine when given for caudal blocks in 56 children 4.1 +/- 1.2 yr old (mean +/- SD). METHODS: Patients scheduled for inguinal hernia repair were randomly given a caudal injection (0.75 ml/kg) of ropivacaine, 0.25% (R0.25 group); ropivacaine, 0.5% (R0.5 group); or bupivacaine, 0.25% (B0.25 group). Postoperative measurements included the duration of analgesia, which was our primary outcome variable, and hemodynamic and respiratory monitoring for 4 h in the recovery room. Thereafter, analgesic requirements for the following 24 h were assessed by an independent observer on the ward using an observational pain-discomfort scale, which gives a cumulative score from 5 to 15 to estimate the quality of analgesia by assessment of behavioral objective parameters. Plasma levels of ropivacaine were measured before the procedure was started and 5, 10, 15, 20, 25, 30, and 45 min and 1, 2, 4, 6, 8, and 24 h after caudal block. RESULTS: A significantly longer (P < 0.0001) duration of analgesia (median [range]) was observed in the R0.5 group (1,440 [335-1,440] min), whereas the R0.25 group (208 [175-340] min) and the B0.25 group (220 [100-390] min) were comparable. All groups showed a significant decrease in mean arterial blood pressure and heart rate from baseline values, but differences between groups were not observed. CONCLUSION: Ropivacaine is well tolerated and provides effective analgesia when given for caudal blockade in small children for inguinal hernia repair.

Amides↗
PubMed1998

[Combined sciatic nerve-3 in 1 block in high risk patient].

BACKGROUND: We report on a case of combined sciatic nerve block and 3-in-1 block for amputation of lower limb in an ASA IV-V patient 6 days after intraoperative cardiopulmonary resuscitation following induction of general anaesthesia. CASE REPORT: A 54-year old male patient was admitted for necrosectomy of a crural ulcer due to end-stage peripheral vascular disease and non-insulin dependent diabetes mellitus. The patient also suffered from toxic cardiomyopathy. After induction for general anaesthesia the haemodynamic situation deteriorated progressively and ended up in cardiac arrest with consequent successful cardiopulmonary resuscitation. The operation was cancelled and the patient was admitted to the intensive-care unit, where he was extubated after 2 days of further haemodynamic stabilisation. Following development of a septic situation of the lower limb the patient was again admitted for amputation six days after the cardiopulmonary resuscitation. Regional anaesthesia was conducted with a combination of a sciatic nerve block via the posterior approach and a 3-in-1 block facilitated by ultrasonographic guidance. For each of the blocks we used 20 mL mepivacaine 1%. Sensory blockade was sufficient and the patient remained haemodynamic and respiratorily stable. DISCUSSION AND CONCLUSIONS: The combined sciatic and 3-in-1 block is a rarely used technique, but for haemodynamically unstable patients it is a safe method for surgery of the lower limb.

Amputation, Surgical↗
PubMed1998

Magnesium sulfate reduces intra- and postoperative analgesic requirements.

UNLABELLED: In a randomized, double-blind study with two parallel groups, we assessed the analgesic effect of perioperative magnesium sulfate administration in 46 ASA physical status I or II patients undergoing arthroscopic knee surgery with total i.v. anesthesia. The patients received either magnesium sulfate 50 mg/kg preoperatively and 8 mg.kg-1.h-1 intraoperatively or the same volume of isotonic sodium chloride solution i.v. Anesthesia was performed with propofol (2 mg/kg for induction, 6-8 mg.kg-1.h-1 for maintenance), fentanyl (3 micrograms/kg for induction), and vecuronium (0.1 mg/kg for intubation). Intraoperative pain was defined as an increase of mean arterial blood pressure and heart rate of more than 20% from baseline values after the induction of anesthesia and was treated with bolus fentanyl (1-2 micrograms/kg). Postoperative analgesia was achieved with fentanyl (0.5 microgram/kg) and evaluated using the pain visual analog scale for 4 h. During the intraoperative and postoperative periods, patients in the magnesium group required significantly less fentanyl than those in the control group (control group 0.089 +/- 0.02 microgram.kg-1.min-1 versus magnesium group 0.058 +/- 0.01 microgram.kg-1.min-1; P < 0.05 and control group 0.021 +/- 0.013 microgram.kg-1.min-1 and magnesium group 0.0031 +/- 0.0018 microgram.kg-1.min-1; P < 0.01 for intraoperative and postoperative periods, respectively). We conclude that, in a clinical setting with almost identical levels of surgical stimulation, i.v. magnesium sulfate administration reduces intraoperative and postoperative analgesic requirements compared with isotonic sodium chloride solution administration. IMPLICATIONS: The perioperative administration of i.v. magnesium sulfate reduces intra- and postoperative analgesic requirements in patients with almost identical levels of surgical stimulus. Our results demonstrate that magnesium can be an adjuvant to perioperative analgesic management.

Adult↗
PubMed1998

[Acupuncture and ganglionic local opioid analgesia in trigeminal neuralgia].

Trigeminal neuralgia (TN) is defined as a chronic, severe, electrifying and burning pain in one side of the face. The attacks are initiated by tactile irritations in a so-called trigger area of the trigeminal nerve and are perceived within the borders of this nerve's innervation. TN is a chronic condition which initially goes into spontaneous remission but these become fewer as the condition progresses. TN is classified as symptomatic when the etiology is known and as idiopathic when the etiology is unknown. There are various forms of treatment: drugs such as anticonvulsants, local ganglionic opioid analgesia (GLOA) at the superior cervical ganglion or sphenopalatine ganglion, percutaneous intervention at the trigeminal ganglion as well as neurosurgery. None of these various procedures has been found to be the most suited and best method. A retrospective analysis of the data of 39 patients who had sought treatment for TN at our pain and acupuncture outpatients' department from 1993 to 1994 was undertaken. Group A (n = 17) had received carbamazepine and acupuncture therapy, group B (n = 11) carbamazepine and GLOA + acupuncture, whereas group C (n = 11) had received carbamazepine and GLOA without acupuncture. All subjects had taken carbamazepine for at least 4 weeks and their plasma levels were within the therapeutic range. Acupuncture therapy was carried out once a week and the number recorded. GLOA was carried out with 0.045 mg buprenorphine at the superior cervical ganglion or the sphenopalatine ganglion as a series of at least 5 injections. The number of attacks of pain and the degree of pain (visual analogue scale [VAS]) were documented. The reduction in pain was categorized in 4 groups: I = pain free, II = reduction of at least 50% on the VAS, III = reduction of less than 50% on the VAS, and IV = no improvement. The statistical analysis was carried out using the chi 2-text, p < 0.05 was considered as significant. Of the groups who received acupuncture as an additive, 8 of the 17 subjects of group A, and 5 of the 11 subjects of group B were pain free, but only 2 of the 11 subjects of group C (no acupuncture). The results of the patients with marked pain reduction (category II) were similar. The most patients with no improvement were from the group which did not receive acupuncture (C). The statistical analysis showed significant differences in the categories I, II, and IV between groups A and C. These results show that the combined use of acupuncture and carbamazepine with/without GLOA achieves an additional therapeutic effect in the treatment of trigeminal neuralgia. The addition of acupuncture seems to have a superior effect to the addition of GLOA. These results support the use of acupuncture as an additional form of therapy for the treatment of trigeminal neuralgia.

Acupuncture Therapy↗