bluuebunny/crossref_metadata_2025 huggingface dataset:
Isoflurane inhibits muscle fasciculations caused by succinylcholine in children
Authors: Randell T. , Yli‐Hankala A. , Lindgren L.
Published: January 2009

The incidence and intensity of muscle fasciculations as well as the occurrence of cardiac arrhythmias following succinylcholine were evaluated in 36 premedicated children (1.0–5.7 years) after intravenous induction with thiopentone or after inhalation induction with isoflurane (3.75 vol‐% in 70% nitrous oxide in oxygen). The study was randomized. In the thiopentone group, fasciculations were seen in all children and in the isotlurane group in 5 of 18 children (P<0.001). The median of the duration of fasciculations was 15 s with a minimum of 5 s and maximum of 36 s (1st quartile 9 s and 3rd quartile 20 s) in the thiopentone group and 0 (0–15) s with a 1st quartile of 0 and a 3rd quartile of 3 s in the isoflurane group (P<0.001). No cardiac arrhythmias were noted in either group. In conclusion, isoflurane in nitrous oxide inhibits succinylcholine‐induced muscle fasciculations in children.
Direct vascular effect of ropivacaine in femoral artery and vein of the dog
Authors: NakamuraM.D. K. , Toda H. , Kakuyama M. , Nishiwada M. , Yamamoto M. , Hatano Y. , Mori K.
Published: January 2009

A study was conducted to examine the direct vascular effect of ropivacaine, in comparison with the effect of bupivacaine and lidocaine. Changes in tension induced by ropivacaine (10‐5‐3 × mol 1‐1), bupivacaine (10‐5‐3 times 10‐3 mol 1‐1) and lidocaine (10‐5‐10‐2 mol 1‐1) were examined cumulatively in vascular rings of dog femoral artery and vein under basal tension, or in those which had been precontracted with phenylephrine submaximally in Krebs' bicarbonate solution at 37°C aerated with 95% O2 and 5% CO2 (pH 7.4). The change in tension induced by lo‐2 moll‐1 ropivacaine was tested under basal tension in vascular rings bathed in HEPES buffer (pH 6.8). Ropivacaine induced greater constriction than bupivacaine at concentrations over 10‐5 mol 1‐1 in vascular rings under basal tension (P<0.01). The maximal contraction was induced by ropivacaine at mol 1‐1, averaging 51.5± 2.8% (n = 11) and 27.0± 3.7% (n= 12) of the maximal contraction induced by epinephrine in the artery and vein, respectively, and the contractions induced by ropivacaine at 10‐3 mol 1‐1 were 16.3± 2.0% (n=11)and 5.5± 1.1% (n=9), respectively. Phenylephrine (10‐6mol 1‐1)‐precontracted artery was contracted significantly by ropivacaine at 3 times 10‐4 mol 1‐1 and mol 1‐1, and by bupivacaine at 3 times 10‐3 mol 1‐1, whereas the phenylephrine 10‐6mol 1‐1)‐precontracted vein was relaxed by these anesthetics. Lidocaine did not exert constricting effects. It is concluded that ropivacaine is a potent vasoconstrictor, although its constrictive effect is slight at 10‐2 mol 1‐1, which may be relevant to the clinical local concentration.
Blockade of the abdominal muscles measured by EMG during lumbar epidural analgesia with ropivacaine – a double‐blind study
Authors: Zaric D. , Axelsson K. , Philipson L. , Nydahl P.‐A. , Larsson P. , Jansson J.‐R. , Leissner P.
Published: January 2009

A single shot of 20 ml of 1%, 0.75% or 0.5% ropivacaine was administered epidurdlly (at L2/3 level) to 30 volunteers, in a double‐blind manner. The blockade of the rectus abdominis muscle was measured quantitatively by registration of the average rectified electromyographic signal (AREMG) at the T7, T9 and T11 motor segmental levels and with a qualitative test for blockade of the rectus abdominis muscle (the so‐called RAM test). The maximal cranial spread ofanalgesia, evaluated by the pin‐prick method, was not significantly different for the three concentrations (T8‐T10 dermatome; median value). The intensity of motor blockade, measured by the AREMG method, increased progressively from the T7 segment and caudally with all three concentrations. The blockade was partial (Le. 85–25% of baseline AREMG activity was present at its maximum) in all subjects. When the effect of the three concentrations of ropivacaine was compared at the same segmental level, the intensity and duration of maximal motor blockade seemed to be dose‐dependent, but the difference was not statistically significant. The total duration of motor blockade was shorter with the 0.5% solution than with the higher concentrations. The AREMG method gave a more exact and graded picture of blockade of the rectus abdominis muscle than the RAM test. The duration of sensory blockade did not outlast motor blockade at any level. In half of our subjects the maximal spread of sensory blockade was either equal to or higher than the spread of partial motor block. In the other half, this relationship was reversed ‐ the maximal cranial level of partial motor block was 1–4 segments higher than the maximal level of analgesia.
Haemodynamics and fluid balance after intravenous infusion of 1.5% glycine in sheep
Authors: StalbergM.D. H. P. , Hahn R. G. , Hjelmqvist H. , Ullman J. , Rundgren M.
Published: January 2009

With the aim of studying the pathophysiological background of the “TUR syndrome”, we gave six conscious ewes an intravenous infusion of 57 ml/kg of 1.5% glycine solution over 40 min. Isotonic saline infusions served as controls. Central haemodynamics were monitored. The plasma concentrations of protein, K, Na and vasopressin, and plasma osmolality were measured repeatedly for up to 4 h. The urinary excretions of Na, K and osmoles were also followed. Both infusions caused an elevation of the mean arterial pressure. With glycine, the pressure increased from 93 ± 4 to 112 ± 12 mmHg (12.4 ± 0.5 to 14.9 ± 1.6 kPa) (mean ± s.d.). The pulmonary capillary wedge pressure increased from 7±3 to 16±3 mmHg (0.9 ± 0.4 to 2.1 ± 0.4 kPa) and remained slightly elevated. The central venous pressure rose from 2 ± 3 to 11 ± 3 mmHg (0.3 ± 0.4 to 1.5 ± 0.4 kPa) but returned to baseline within 30 min after the infusion. Infusion of glycine resulted in a decrease in the plasma Na concentration from 144 ± 3 to 114 ± 4 mmol/l. The plasma osmolality decreased from 290 ± 2 to 280 ± I mosmol/l, and remained low. There was a median 6‐fold increase in plasma vasopressin concentration, while saline did not elicit vasopressin release. Despite the absence of electrolytes in glycine solution, the urinary excretion of sodium amounted to 106 ± 40 mmol. We conclude that i.v. infusion of 1.5% glycine solution in sheep causes a transient circulatory strain and natriuresis. Moreover, a vasopressin‐mediated reduction of maximal water excretion contributes to persisting hypoosmolality.
Health status and the preoperative change in serum potassium concentration
Authors: HAHN R. G. , LÖFGREN A. , NORDIN A. M.
Published: January 2009

When evaluating preanaesthetic abnormal serum potassium (S‐K) levels, the anaesthetist often relies upon blood tests performed on admission to hospital 1 or more days prior to surgery. However, the S‐K is often altered between admission to hospital and the induction of anaesthesia. In this study, we examined the effects of health status and medication on the preoperative change in S‐K concentration in 150 unselected elderly men awaiting uroiogical operations. Oral daily medication was not given preoperatively on the day of surgery. One third of the patients showed a change of 0.4 mmol/1 or more (range – 1.1 to + 1.2), with an increase as common as a decrease. Those on treatment with calcium‐channel blockers or diuretics showed an increase in the S‐K concentration in the preoperative period, while patients using oral antidiabetics showed a decrease. The use of β‐adrenoceptor antagonists was not a significant predictor of the change in S‐K concentration. In conclusion, we found that alterations in serum potassium were common prior to surgery, but only a small fraction of this variance could be accounted for by health status and medication.
Enhancement by ischemia of the risk of cardiac disorders, especially fibrillation, in regional anesthesia with bupivacaine
Authors: FREYSZ M. , TIMOUR Q. , BERTRIX L. , LOUFOUA‐MOUNDANGA J. , OMAR S. , FAUCON G.
Published: January 2009

The impairment of intraventricular conduction by bupivacaine may result in reentrant arrhythmias including ventricular fibrillation. The concentrations responsible for serious accidents are high (5.0 to 8.0 μg/ml), but likely to be lowered by myocardial ischemia which gives rise to similar disorders. Therefore we did an electrophysiological study of bupivacaine's effects in an ischemic area of the myocardium. Monophasic action potential (MAP) of the ventricular myocardium was recorded in 30 anesthetized, open‐chest pigs. Conduction time and effective refractory period were also measured. Data were obtained during short periods (10–15 s) of pacing at 180 beats/min, but ventricular beats remained governed by the sinus node in the intervals. Ischemia was produced by occluding the left anterior descending coronary artery completely but transiently (up to 8 min), not far from its origin. Comparison was made between the effects of bupivacaine i.v. (n = 10), ischemia (n= 10) and both factors (n= 10). Two min after injection of bupivacaine 2.0 mg/kg (plasma levels 2.0–3.0 μg/ml), the duration of MAP was only slightly (7.5–15%) prolonged and its ischemia‐induced shortening only slightly attenuated by bupivacaine. At the same time, conduction time was considerably (75–150%) lengthened and its ischemia‐induced lengthening enhanced, so that ventricular fibrillation induced by coronary occlusion occurred sooner (about 100 instead of 300 s) in the presence of bupivacaine. Consequently, bupivacaine should be used only with caution in individuals whose myocardium is ischemic or liable to ischemia episodes.
Increased haemodilution in hypotension induced by epidural anaesthesia
Authors: HAHN R. G.
Published: January 2009

This study examined whether the increased haemodilution from fluid loading in patients who develop hypotension at the onset of epidural anaesthesia (EDA) can be explained by high‐level blockade or by stressinduced elevation of the blood glucose concentration. In 20 men aged between 53 and 87, crystalloid volume loading was carried out with 10 ml‐kg‐1 b.w. and EDA was induced with mepivacaine 2% and adrenaline 1:200 000. Irrespective of the blood pressure reaction to the blockade, there was no change in blood glucose level. A strong linear correlation between haemodilution and arterial pressure was found, in spite of unchanged blood glucose levels, in 10 patients in whom EDA was induced with bupivacaine 0.5%, and in 10 patients who received spinal anaesthesia with tetracaine 1 %. There was no correlation between the haemodilution and the extent of sensory analgesia. These results support the view that low arterial pressure alone triggers the increased haemodilution observed during EDA‐induced hypotension.
Endotracheal tube versus face mask with and without continuous positive airway pressure (CPAP)
Authors: JOUSELA I.
Published: January 2009

Various ways of delivering continuous positive airway pressure (CPAP) have been extensively studied, with little attention, however, being paid to the effects of an intubation tube compared with breathing through a face mask, with or without CPAP. Pulmonary and cardiovascular variables were measured while 12 patients recovering from coronary artery bypass grafting were spontaneously breathing at ambient airway pressure, then at 7.4 mmHg (1 kPa) CPAP, and again at ambient pressure just before extubation. The same stages were repeated immediately after extubation, with patients breathing through a tight‐fitting face mask. Arterial oxygen tension (Pao2, mean ± s.d.) was better when the patients were breathing at ambient pressure through a face mask (11.7±2.8 kPa) than when they were intubated (10.6±2.4 kPa, P < 0.05). Compared with ambient pressure, CPAP (7.4 mmHg) (1 kPa) increased Pao2 in both modes (13.4 ± 3.5 kPa with mask, and 12.6 ± 3.5 kPa when intubated, n.s.). The best arterial oxygen saturation was measured during CPAP with a face mask (96± 1%). Cardiac output remained unchanged in all the breathing modes. After coronary artery bypass grafting, spontaneous breathing with a face mask resulted in better Pao2 than breathing through an endotracheal tube, both with and without 7.4 mmHg (1 kPa) CPAP. This study indicates that unnecessary delay in extubation should be avoided.
Effects of PEEP on splanchnic hemodynamics and blood volume
Authors: FUJITA Y.
Published: January 2009

The effects of intermittent positive pressure ventilation with PEEP on splanchnic circulation and hepatic oxygen supply were studied in six beagles. PEEP of 0, 0.5 and 1.0 kPa (0, 5, 10 cmH2O, PEEP0, PEEP5 and PEEP10, respectively) of 30 min duration was applied in a random sequence. Hepatic arterial blood flow and portal venous blood flow were measured by electromagnetic flow meters. Blood volume changes in the splanchnic area were assessed from hepatic and splenic dimensions determined by sonomicrometry. PEEP5 and PEEP10 were associated with proportional decreases in both hepatic blood flow and cardiac output, while mean arterial pressure remained unchanged. Reflecting the decrease in hepatic blood flow, the hepatic oxygen supply decreased with the level of PEEP, and hepatic venous hemoglobin oxygen saturation was significantly less during PEEP10 (55.1 ± 14.3%) than during PEEP5 (62.6 ± 17.4%) and PEEP0 (62.3 ± 11.9%). Hepatic venous and portal venous pressure increased with the level of PEEP. Hepatic dimensions increased by 7–8% and 16–19% during PEEP5 and PEEP10, respectively, but no significant changes in splenic dimension were observed. We conclude that PEEP5 and PEEP10 are accompanied by a decrease in hepatic blood flow and oxygen supply along with hepatic congestion.
Comparison of the ventilatory effects of morphine and buprenorphine in children
Authors: HAMUNEN K. , OLKKOLA K. T. , MAUNUKSELA E.‐L.
Published: January 2009

This study was a prospective, randomized comparison of the ventilatory effects of equianalgesic single‐doses of morphine, 100 μg/kg, and buprenorphine, 3.0 μg/kg, administered intravenously to 20 children (5–8 years of age) after elective ophthalmic surgery. The decrease in ventilatory rate and acute change in the arteriolar oxygen saturation and the increase in end‐tidal CO2 levels were statistically significantly greater in magnitude and duration after buprenorphine than after morphine. For both drugs, the time, duration and magnitude of ventilatory changes varied appreciably between individuals. No child had apnea or hypoventilation requiring assistance. The authors conclude that acutely administered buprenorphine depresses ventilation to a greater degree than morphine. The maximal ventilatory effect of buprenorphine occurs later than with morphine, and ventilatory depression after buprenorphine may develop late. For safety, all children given opioids intravenously should be observed until they are fully responsive and ventilatory control has stabilized.
Effective concentration 50 for propofol with and without 67% nitrous oxide
Authors: DAVIDSON J. A. H. , MACLEOD A. D. , HOWIE J. C. , WHITE M. , KENNY G. N. C.
Published: January 2009

The Effective Blood Concentration (EC) of propofol required to prevent response to surgical incision was determined in 65 ASA I or II female patients breathing either 100% oxygen or 67% N2O in oxygen. Propofol was administered via a microcomputer‐controlled infusion system programmed to maintain the blood propofol concentration at predetermined target values. The blood propofol concentrations predicted by the micro‐computer were validated by measurement of whole blood propofol concentration. Predicted and measured concentrations differed during infusion of propofol, but became similar after discontinuing the infusion for at least 90 s, suggesting that equilibration within the central compartment was incomplete during infusion. The response to the initial incision was observed and probit analysis used to determine the predicted blood concentration at which 50% of patients responded. The predicted EC50 for propofol/N2O/ O2 and propofol/O2 was 4.5 μg ml‐1 and 6.0 μg ml‐1 respectively, and the measured EC50 propofol/N2O/ O2 and propofol/O2 was 5.36 μg ml‐1 and 8.1 μg ml‐1, 67% nitrous oxide in oxygen reducing the predicted EC50 by 25% and the measured EC50 of propofol by 33%. The predicted EC may be more representative of the equilibrated concentration in the central compartment and thus reflective of tissue propofol concentrations.
Favorable effects of epidural analgesia on hemodynamics, oxygenation and metabolic variables in the immediate post‐anesthetic period
Authors: HOSODA R. , HATTORI M. , SHIMADA Y.
Published: January 2009

Fourteen adult patients undergoing elective major abdominal surgery were divided into two groups. One group received epidural and general anesthesia (epidural group), and 20 ml of 0.125% bupivacaine and 2 mg of morphine were administered epidurally about 30 min before the end of the operation for post‐anesthetic analgesia. The other group (control group) received general anesthesia alone with nitrous oxide, oxygen and enfiurane. Flow‐directed pulmonary arterial and radial arterial catheters were inserted preoperatively, and hemodynamic, respiratory, neuroendocrine and metabolic variables were measured serially. The data were compared during anesthesia and the immediate post‐anesthetic recovery period. In the control group, the plasma epinephrine level in the post‐anesthetic recovery period increased about four times over the anesthetic period. Oxygen consumption was increased and mixed venous oxygen saturation was decreased significantly. There was a close linear correlation between oxygen consumption (Y) and plasma epinephrine (X) level: Y = 285.7X + 90.5 (P < 0.01, r = 0.72). On the other hand, plasma epinephrine, oxygen consumption and mixed venous oxygen saturation did not change significantly in the epidural group in the post‐anesthetic recovery period. There was also a close linear correlation between oxygen consumption (Y) and oxygen delivery (X): Y = 0.22X ‐32.0 (P < 0.01, r = 0.89). We conclude that the surgical stress and anesthetic reversal may seriously influence neuroendocrine responses and subsequently increase plasma epinephrine. Tissue oxygenation and metabolic imbalance may occur due to the rapid increase of epinephrine in the postanesthetic recovery period. Epidural analgesia at this period may play a more important role and have a more favorable effect on the tissue metabolism.
Duration of vecuronium‐induced neuromuscular blockade predicted by dose and onset time
Authors: RøRVIK K. , HUSBY P. , GRAMSTAD L. , VAMNES J. S. , BøE O. E.
Published: January 2009

We investigated the adequacy of using dose and onset time as variables to predict the duration of action of vecuronium in patients. The onset time until 95% twitch depression and the duration until 25% twitch recovery were measured for doses ranging from 0.1 to 0.3 mg kg‐1. Statistical analyses were performed by simple and multiple regressions. The duration of action was better predicted by dose (r2 = 0.61) than by onset time (r2 = 0.51). However, the predictability was significantly improved by a multiple regression model of the variables, and the explanatory power was largest when using the square root of duration as the dependent variable (r2 = 0.69). We conclude that the duration of neuromuscular blockade after vecuronium can be predicted more accurately by the combined use of dose and onset time than by dose alone.
Fluidity state of lymphocyte plasma membrane in malignant hyperthermia susceptible pigs and humans
Authors: ROCK E. , MOTTA C. , VIGNON X. , KOZAK‐RIBBENS G.
Published: January 2009

Recent studies suggest that abnormalities occur at the lipid level in malignant hyperthermia susceptible humans and pigs. To test this hypothesis, we first investigated the physical state of plasma membranes of lymphocytes isolated from normal and malignant hyperthermia susceptible swine. In halothane‐challenged pigs, malignant hyperthermia susceptibility was also assessed by ryanodine binding assay on purified sarcoplasmic reticulum membranes. The results clearly show that plasma membrane of lymphocytes from malignant hyperthermic pigs are significantly more fluid than controls. We then attempted to apply the same methodology to lymphocytes prepared from human patients previously diagnosed by the halothane and caffeine contracture test. In that case, there was no clear relationship between malignant hyperthermia susceptibility and the fluidity state of lymphocyte plasma membranes.
CSF neuropeptides in cancer pain: effects of spinal opioid therapy
Authors: SAMUELSSON H. , EKMAN R. , HEDNER T.
Published: January 2009

The cerebrospinal fluid (CSF) levels of the opioid peptides met‐enkephalin (ME), beta‐endorphin (BE) and dynorphin (DYN) as well as the putative sensory neuropeptides substance P (SP), somatostatin (SOM), calcitonin gene related peptide (CGRP) and vasoactive intestinal polypeptide (VIP) were determined in 10 patients with severe nociceptive pain due to malignancy, before and after initiation of spinal opioid therapy, and in 10 control patients. Pain intensity, evaluated by means of a 100‐mm visual analog scale (VAS), was reduced from 39 ± to 18±10 for continuous pain and from 70± 10 to 10 ± 8 for intermittent pain (means ± s.e.mean). Lumbar CSF immunoreactive ME and DYN concentrations were significantly increased (P = 0.05) and BE and VIP were significantly decreased (P < 0.05) in the pain patients. A slight, but nonsignificant (P = 0.06) decrease in SP‐like immunoreactivity was found after initiation of spinal opioid therapy. Visceral pain seemed to be associated with low immunoreactive SP and ME concentrations compared to somatic pain. A highly significant correlation was found between SP and ME (P < 0.001) and to a lesser extent also between other peptides. We conclude that the concentrations of the endogenous opioids were more affected by nociceptive pain states than the non‐opioid peptides. The origin of pain may also influence the results. The postulated inhibition of peptide release by spinal opioid application seemed to be present for SP, but could otherwise not be confirmed.
Inhibition of brain cell excitability by lidocaine, QX314, and tetrodotoxin: a mechanism for analgesia from infused local anesthetics?
Authors: BUTTERWORTH J. , COLE L. , MARLOW G.
Published: January 2009

Local anesthetic infusions have been used to provide analgesia in a variety of painful conditions. The mechanism for this drug effect remains unknown. To better define the electrical effects of lidocaine concentrations comparable to those obtained during analgesic infusions, lidocaine (0.05‐3 mmol l‐1), QX314 (an obligatorily charged, quaternary lidocaine derivative applied within the cells), and tetrodotoxin (10 nmoll‐1) were applied to rat hippocampal pyramidal cells. The three drugs, which inhibit Na+currents by varying mechanisms, produced tonic increases in (firing) current threshold, and decreases in the amplitude of action potentials measured using an intracellular microelectrode technique. Lidocaine inhibited action potential spikes and increased current threshold in a concentration‐dependent fashion. Lidocaine 50 and 100 μmol 1‐1did not inhibit action potentials, but increased firing threshold by nearly 100%. Lidocaine 1–3 mmol l‐1significantly inhibited action potential amplitude and increased threshold by as much as 800%. Similarly, QX314 and tetrodotoxin produced greater increases in current threshold than in action potential amplitude. QX314 produced phasic (or frequency‐dependent) block during trains of stimuli at 1 Hz, even when almost no tonic block was present. Lidocaine produced less phasic block than QX314, and required both greater tonic block and more frequent stimulation to produce the phenomenon. Tetrodotoxin demonstrated no phasic block. Increases in current threshold occurred in lidocaine concentrations associated with analgesia and toxicity; inhibition of action potentials occurred scarcely at all at these concentrations. Thus, tonic increases in current threshold may underlie analgesia and supplementation of general anesthesia by intravenous lidocaine.
Anaesthesia for coronary artery bypass grafting: opioid‐analgesia combined with either flunitrazepam, propofol or isoflurane
Authors: HAESSLER R. , SCHWENDER D. , LEPPMEIER U. , KLASING S. , RINDFLEISCH F. , PETER K.
Published: January 2009

This is a prospective, open, randomized study comparing three different anaesthetic regimens with respect to haemodynamic stability (cardiac index and pressure measurements), ischaemia (ECG), and loss of awareness (midlatency auditory evoked potentials) in 58 patients undergoing coronary artery surgery. Anaesthesia was based on fentanyl 0.01 mg kg‐1 bw for induction and 0.8‐2.0 mg h‐1 in combination with nitrous oxide for maintenance before cardiopulmonary bypass and 0.2‐0.6 mg h‐1 without nitrous oxide during and after cardiopulmonary bypass. Eighteen patients were anaesthetised with flunitrazepam 0.01 mg kg‐1 bw for induction and received thereafter 1–2 mg h‐1 for maintenance (group F). In 40 patients anaesthesia was induced with etomidate and maintained with either isoflurane 0.4‐1.2 vol% (group I) or propofol 4–10 mg kg‐1 bw h‐1 (group P). Vasodilators and inotropes were used for haemodynamic control when needed. Haemodynamic variables and ECG were studied at five timepoints (awake; after induction before surgery; after sternotomy; before cardiopulmonary bypass; and 20 min after separation from bypass). During surgical stimulation, vasodilators were needed significantly more frequently in group F, than in groups I and P. Surgery and sternotomy caused an increase in SVI and APs/SV in all groups. Differences between the groups were only found for systemic pressures, which after sternotomy were lowest in group I and before cardiopulmonary bypass were highest in group F. After termination of bypass all groups showed an increase in HR and a decrease in SVI, SVR, and LVSWI compared to the awake state, while CI remained unchanged. The only differences noted between the groups were a lower PCWP and a smaller reduction in SVR with propofol compared to the others and higher APs/SV with propofol compared to isoflurane. Concerning ST segment changes (> 0.1 mV, leads II and/or V5) at the five measurement times, significant differences were found comparing groups F and P after sternotomy (P < 0.10) and comparing groups F and I after separation from CPB (P <0.05), group F showing the highest incidences of ischaemic events. A blinded evaluation of auditory evoked potentials demonstrated more reduced midlatency auditory potentials after sternotomy during isoflurane and propofol anaesthesia than during flunitrazepam. The authors conclude that fentanyl supplemented with isoflurane or propofol was unequivocally superior to supplementation with flunitrazepam.
Intrathecal anaesthesia in patients under 45 years: incidence of postdural puncture symptoms after spinal anaesthesia with 27G needles
Authors: BRATTEBO G. , WISBORG T. , RODT S. Å. , BJERKAN B.
Published: January 2009

Postoperative headache and backpain has limited the use of intrathecal anaesthesia in younger patients (15–45 years). We studied postoperative complaints among 133 healthy young patients (mean age 30.0 years, 47% females) who received spinal anaesthesia with a 27G needle. Postoperatively, 5 patients (4%) complained of postdural puncture headache (PDPH), 18 (14%) reported nonspecific headache, while 27 (20%) suffered from backpain. PDPH was not related to sex, age, day‐care surgery, number of puncture attempts, or obstetric procedures. Backpain was significantly more common among females, and among in‐patients. One hundred and sixteen patients (87%) would accept spinal anaesthesia if they were to undergo the same surgical procedure again. Compared to other studies, we find the incidence of postanaesthetic complaints to be acceptable, also among day‐care patients. The PDPH seemed to be lightly incapacitating, and only one patient required blood patching.
Cervical epidural steroid injection for cervicobrachialgia
Authors: STAV A. , OVADIA L. , STERNBERG A. , KAADAN M. , WEKSLER N.
Published: January 2009

Fifty patients with chronic resistant cervicobrachialgia were randomly divided into two groups. Twenty‐five patients (group A) were treated with cervical epidural steroid/lidocaine injections and 17 patients (group B) were treated with steroid/lidocaine injections into the posterior neck muscles. Another eight patients from group B were excluded from the study because they had started the process of litigation of insurance claims and their subjective analysis of pain relief might therefore not be trustworthy. One to three injections were administered at 2‐week intervals according to the clinical response. All patients continued their various pre‐study treatments: non‐steroidal anti‐inflammatory drugs, non‐opioid analgesics and physiotherapy. Pain relief was evaluated by the visual analogue scale 1 week after the last injection and then 1 year later. One week after the last injection we rated pain relief as very good and good in 76% of the patients in group A, as compared to 35.5% of the patients in group B. One year after the treatment 68% of the group A patients still had very good and good pain relief, whereas only 11.8% of group B patients reported this degree of pain relief. These differences were statistically significant. We failed to achieve significant improvement of tendon reflexes or of sensory loss in both groups, but the increase in the range of motion, the fraction of patients who were able to decrease their daily dose of analgesics, and recovery of the capacity for work were significantly better in group A. We encountered no complications in either group of patients. We conclude that cervical epidural steroid/local anaesthetic injection is an effective method for achieving immediate and long‐standing pain relief and improvement in motion and performance in chronic resistant cervicobrachialgia.
Biochemical changes in malignant hyperthermia susceptible swine: cyclic AMP, inositol phosphates, α1, β1‐ and β2‐adrenoceptors in skeletal and cardiac muscle
Authors: SCHOLZ J. , STEINFATH M. , ROEWER N. , PATTEN M. , TROLL U. , SCHMITZ W. , SGHOLZ H. , EsCH J. SCHULTE AM
Published: January 2009

It has been presumed that alteration in the concentrations of second messengers leads to alterations in the function of the ryanodine receptor. Consequently, we have determined the basal content of cyclic AMP and inositol phosphates in skeletal and cardiac muscle of malignant hyperthermia (MH) susceptible (MHS) and healthy normal control (MHN) swine. Since α,‐ and β‐adrenoceptors are linked to these second messenger systems, the densities of α1,‐ and β‐adrenoceptors were also determined. In skeletal as well as cardiac muscle, a higher basal concentration of almost all of the inositol phosphates was found. Of all inositol phosphates measured, the presumed second messenger inositol 1,4,5‐trisphosphate (1,4,5‐IP3) was mostly concentrated in both tissues. Each MHS sample contained more 1,4,5,‐IP3 than the highest value observed in MHN muscle, indicating that a threshold of 1,4,5‐IP3 concentration for determination of MHS or MHN status can be defined. In addition, MHS skeletal muscle contained more cAMP than MHN, whereas there was no difference between MHS and MHN in cardiac muscle. The changes observed in the different inositol phosphate and cAMP contents were not accompanied by an altered α1,‐ or β‐adrenoceptor density in skeletal or cardiac muscle between MHS and MHN. However, the total number of β‐adrenoceptors of MHN and MHS was significantly higher in cardiac (about 80 fmol/mg protein) than skeletal muscles (about 30 fmol/ mg protein). The cardiac muscles revealed about 80% β1,‐ and 20% β2‐adrenoceptors, whereas skeletal muscles were characterised by over 95% β2‐adrenoceptors. In conclusion, the present study supports the view that altered second messenger systems and, thereby, altered intracellular calcium regulations are at least in part involved in the modulation and development of MH. Moreover, in addition to the skeletal muscle, multiple other organs, e.g. heart, may be affected in MH.
A two‐dose epidural morphine regimen in cesarean section patients: pharmacokinetic profile
Authors: ZAKOWSKI M. I. , RAMANATHAN S. , TURNDORF H.
Published: January 2009

The maternal pharmacokinetics, metabolism of, and possible neonatal transmission of epidural morphine in cesarean section patients were investigated. Maternal plasma, breast milk, and maternal and neonatal urine concentrations of unconjugated and conjugated (UM and CM) morphine were measured in patients given two 5‐mg doses of epidural morphine for post‐cesarean section analgesia. The first dose was administered after delivery and the second dose 24 h later. Maternal venous blood samples (n = 10) were collected at times 0, 0.25, 0.5, 1, 2, 3, 4, 6, 12, and 24 h after each dose, and maternal urine was collected for three consecutive 24‐h periods (n = 30). Maternal breast milk (n = 30), and neonatal urine samples (n = 20) were also collected. Serum, urine, and breast milk UM and CM levels were measured using radioimmunoassay. Pharmacokinetic values were calculated using noncompartmental analysis. The results were expressed as mean ± 1 s.e. mean and analyzed using repeated measures analysis of variance and the pairedt‐test. Maternal serum UM remained 40–50% higher, and CM 50–100% higher in the first hour following dose 2 than the respective values after dose 1 (P< 0.05). Values for AUC, AUMC, Tl/2, and MRT increased 28%, 83%, 35% and 36%, respectively, with the second dose (P< 0.05), while CI decreased 19% (P< 0.05) with no significant difference in Vss. Total urinary excretion of morphine decreased significantly from 1.98 ± 0.15 mg on day 1 to 1.6 ± 0.2 mg and 0.19 ± 0.002 mg on days 2 and 3, respectively (P< 0.01). Breast milk and neonatal urine contained negligible amounts of morphine, signifying minimal neonatal transfer.
Effects of adenosine triphosphate (ATP) on somatosensory evoked potentials in humans anesthetized with isoflurane and nitrous oxide
Authors: ANDOH T. , OHTSUKA T. , OKAZAKI K. , OKUTSU Y. , OKUMURA F.
Published: January 2009

In order to examine the usefulness of adenosine triphosphate (ATP) as an adjuvant to anesthesia for surgery requiring intraoperative somatosensory evoked potential (SSEP) monitoring, we have studied the effects of ATP on SSEPs in patients anesthetized with isoflurane and nitrous oxide (N2O). A control recording of SSEP was performed while anesthesia was maintained with 0.5% end‐tidal concentration of isoflurane in 60% N2O. The recordings were repeated after an ATP infusion had been added to this basal anesthesia at the rates of 100 μgkg bw‐1 min‐1 and 200 μg kg bw‐1 min‐1. SSEP was also studied when end‐tidal isoflurane concentration was increased to 1.5% after cessation of ATP infusion. An infusion of ATP combined with 0.5% isoflurane and 60% N2O effectively inhibited an increase in blood pressure during surgery. The amplitude of the cortical component of SSEP was lowered by 1.5% isoflurane, which also increased both cortical and spinal latencies as well as central conduction time (CCT). In contrast ATP infusions at both rates induced no significant changes in latencies, amplitude and CCT. The results indicate that ATP infusion combined with 0.5% isoflurane in 60% N2O can be a useful anesthetic technique for intraoperative SSEP monitoring because adequate anesthetic depth can be maintained by a low concentration of anesthetics without further suppression of SSEPs.
Increase in lactoferrin and elastase α‐1‐proteinase inhibitor complexes but lack of complement activation and IL‐6 response following thoracic surgery
Authors: WANSCHER M. , TØNNESEN E. , ANTONSEN S. , HOHNDORF K. , NIELSEN L. K. , HANSEN G. L.
Published: January 2009

Polymorphonuclear neutrophil (PMN) stimulation and degranulation can be mediated by the cytokines and by complement activation. The aim of the present study was to measure TNFa, IL‐lα, IL‐6 and C3d in relation to postoperative increase in lactoferrin and elastase α‐1‐proteinase inhibitor (E α‐l‐PI) levels. Eleven patients undergoing thoracic surgery took part in the study. Blood leucocytes, E α‐l‐PI, lactoferrin and C3d were measured preoperatively, at the end of surgery and postoperatively, at 4 h and on day 1, 2, 3 and 5. TNFa, IL‐lα and IL‐6 were measured preoperatively, at the end of surgery and postoperatively, at 4 h, and on days 1 and 5. The leucocyte count, lactoferrin and E α‐l‐PI levels increased significantly postoperatively (P < 0.01). There was no significant change in C3d values. Plasma IL‐6 levels were unchanged in the postoperative period. Plasma TNFa and IL‐lα were detectable at low levels in only two and four patients, respectively. Conclusion: The postoperative increase in blood levels of PMN lactoferrin and E α‐l‐PI complexes observed in the present study was not accompanied by complement activation, or increased blood levels of IL‐6.
Hemodynamic changes associated with thermodilution cardiac output determination in canine acute blood loss or endotoxemia
Authors: NISHIKAWA T.
Published: January 2009

Since the technique of thermodilution (TD) cardiac output measurement,per se, causes hemodynamic alterations, the author examined whether the alterations elicited by iced injectate are augmented in the presence of acute blood loss or endotoxemia, compromized conditions frequently associated with critically ill patients. Acute blood loss (N = 8) and endotoxemia (N = 8) were induced by withdrawing arterial blood approximately 20–30 ml kg‐1over 30 min and by a slow intravenous infusion ofE. coliendotoxin 2.5‐3.0 mg kg‐lover 10 min, respectively, in anesthetized dogs. The magnitudes of decreases in mean arterial and pulmonary artery pressures during slowing of heart rate (HR) following injection of iced injectate 3 ml were slightly less in acute blood loss than in normovolemia, whereas in endotoxemia the degree of mean arterial pressure decrease during slowing of HR following iced injectate 3 ml was slightly less as compared with that before endotoxemia. However, the alterations in other hemodynamic variables following injection of iced injectate 3 ml were similar between dogs with and without acute blood loss or endotoxemia. No profound hemodynamic changes were observed during any TD cardiac output measurements under both conditions. Cardiac output estimated by TD correlated closely with pulmonary blood flow measured by electromagnetic flowmeter in endotoxemia (r > 0.9) but not during acute blood loss. These results indicate that TD cardiac output determination does not cause serious hemodynamic alterations in endotoxemia or acute blood loss, and can estimate right ventricular output accurately in endotoxemia but not in acute blood loss.
A double‐blind comparison of lidocaine and mepivacaine during epidural anaesthesia
Authors: TERM T. , YUKIOKA H. , FUJIMORI M.
Published: January 2009

The effects of epidural anaesthesia with plain 2% lidocaine or mepivacaine were compared in 200 patients undergoing extracorporeal shock wave lithotripsy in a double‐blind manner. The onset, spread, duration and quality of analgesia were similar in both groups. The numbers of patients who needed vasoconstrictor or atropine were almost equal in both the lidocaine and the mepivacaine groups. Mild but significant hypotension continued for a longer period in the mepivacaine group than in the lidocaine group. A transient decrease in arterial oxygen saturation was seen in two patients receiving lidocaine and in three patients receiving mepivacaine. Mild systemic toxicity was observed in eight patients in both groups, although serious complications such as convulsions did not occur. It is concluded that both drugs can be used equally safely for epidural anaesthesia, although the maximum recommended doses differ.
Precision of a new bedside method for estimation of the circulating blood volume
Authors: CHRISTENSEN P. , ERIKSEN B. , HENNEBERG S. W.
Published: January 2009

The present study is a theoretical and experimental evaluation of a modification of the carbon monoxide method for estimation of the circulating blood volume (CBV) with respect to the precision of the method. The CBV was determined from measurements of the CO‐saturation of hemoglobin before and after ventilation with a gas mixture containing 20–50 ml of CO for a period of 10–15 min. A special Water's to and fro system was designed in order to avoid any leakage when measuring during intermittent positive pressure ventilation (IPPV). Blood samples were taken before and immediately after ventilation with the CO gas mixture. The amount of CO administered during each determination of CBV resulted in an increase in the CO saturation of hemoglobin of 2.1%‐3.9%. A theoretical noise propagation analysis was performed by means of the Monte Carlo method. The analysis showed that a CO dose corresponding to an increase of less than 2% will result in an unacceptable coefficient of variation of repeated estimates. In the experimental study the coefficient of variation of repeated estimates of CBV was determined from duplicate measurements of CBV in nine healthy subjects and in nine intensive care patients. The coefficients of variation were 6.2% and 4.7% in healthy and diseased subjects, respectively. Furthermore, the day‐to‐day variation of the method with respect to the total amount of circulating hemoglobin (nHb) and CBV was determined from duplicate estimates separated by 24–48 h. In conclusion, determination of CBV can be performed with an amount of CO that gives rise to a harmless increase in the carboxyhemoglobin concentration. The precision of the method is sufficient for clinical purposes.
Undiagnosed amyotrophic lateral sclerosis and respiratory failure
Authors: KUISMA M. J. , SAARINEN K. V. , TEIRMAA H. T.
Published: January 2009

Two patients suffering from exacerbation of chronic respiratory insufficiency due to previously undiagnosed amyotrophic lateral sclerosis are reported. Both patients had a false diagnosis of asthma with a restrictive component. The diagnosis had been made after pulmonary function studies, and both patients had also treatment for asthma. A central etiology was suspected when weaning from mechanical ventilation proved unsuccessful during respiratory failure, necessitating intensive care. A neurologic examination and a typical electroneuromyography recording confirmed the diagnosis of amyotrophic lateral sclerosis. Neuromuscular disorders must be excluded when treating patients with respiratory failure, even if they already have the diagnosis of chronic pulmonary disease.
Patient–controlled analgesia (PCA) leads to more postoperative pain relief, but also to more fatigue and less vigour
Authors: PASSCHIER J. , RUPREHT J. , KOENDERS M. E. F. , OLREE M. , LUITWIELER R. L. , BONKE B.
Published: January 2009

This investigation evaluated patient–controlled analgesia (PCA) for subjective well–being and mood in the postoperative period in comparison with the intramuscular (im) administration of morphine given on demand. Patients scheduled for elective upper abdominal surgery were assigned at random to either PCA (n = 17) or im morphine (n= 14). The PCA group experienced significantly more pain relief and consumed more morphine than those who received im morphine. The PCA patients suffered from more fatigue and showed less vigour than the im group. Neither preoperative trait anxiety nor locus of control was associated with postoperative pain in either of the groups.
Epidural morphine for postoperative pain relief in children
Authors: HENNEBERG S. W. , HOLE P. , HAAS I. MADSEN DE , JENSEN P. J.
Published: January 2009

Epidural morphine for postoperative pain relief is in general use, and has proved to be very efficient in adults. The epidural technique and the use of epidural morphine are much less frequent in children. For 2 years we have prospectively followed 76 children who had epidural morphine for postoperative pain relief after major abdominal surgery. The age distribution was from newborn to 13 years, with a median age of 12 months. It was estimated that 94% of the patients had good analgesia for the first 24 postoperative hours and no other opioids were given. The side effects were few, but one case of respiratory depression was seen and 20% of the children had pruritus. There were four dural punctures and three catheters slipped out accidentally, but otherwise the treatment was continued as long as it was considered necessary (1–11 days). The use of postoperative ventilatory support decreased during the investigation. We observed a change in the sleeping pattern with an increased number of sleep–induced myoclonia during the administration of epidural morphine. In conclusion, the use of epidural morphine in children for postoperative pain relief is very efficient. The minimal effective dose has not been established as yet, but 50 Hg/kg every 8 h, supplemented with small doses of bupivacaine, provides excellent analgesia in the immediate postoperative period after major abdominal surgery. The side effects are few, but the risk of respiratory depression is always present and observation in the intensive care unit or recovery for the first 24 h is strongly recommended.
Attenuation of the pressor response to tracheal intubation with oral nitrendipine
Authors: MAEKAWA N. , MIKAWA K. , NISHINA K. , KAETSU H. , GOTO R. , YAKU H. , TAKAO Y. , OBARA H.
Published: January 2009

The effect of nitrendipine on the cardiovascular responses to tracheal intubation was studied in a placebocontrolled, randomised, double–blind trial. Thirty patients (ASA physical status 1) undergoing elective surgery either 5 or 10 mg nitrendipine, or a placebo orally 3 h before induction of anaesthesia (n = 10 for each group). Anaesthesia was induced with sodium thiopentone 5 mg/kg i.v. and tracheal intubation was facilitated with vecuronium 0.2 mg/kg i.v. Patients receiving the placebo showed a significant increase in the mean arterial pressure and the rate–pressure product in response to tracheal intubation. These increases following intubation were reduced in nitrendipine–treated patients compared with the placebo group (P < 0.05). Oral administration of nitrendipine (5 or 10 mg, 3 h before induction of anaesthesia) was able to attenuate the hypertensive response to tracheal intubation in ASA 1 patients under light anaesthesia. We propose this pharmacological technique with supplementary doses of opioids and/or benzodiazepines for the management of patients with hypertension or coronary artery disease.
Effects of halothane on the synthesis of neurotransmitter amino acids in mouse brain
Authors: WATANABE K. , ARAI T. , AOKI M. , MORI H. , MORI K.
Published: January 2009

The effects of halothane on the synthesis of the three major neuroactive amino acids (θ–aminobutyric acid, aspartate and glutamate) and glutamine, which is closely related metabolically, were investigated in mouse brain using a labelled precursor ([13C]glucose) and a gas chromatography–mass spectrometry system. The ratios of newly synthesised amino acids were increased relative to baseline values when animals were exposed to 1% halothane, and decreased when they were exposed to 2% halothane. These findings suggest that halothane affects the synthesis of neurotransmitter amino acids in a concentration–dependent manner, without discrimination between excitatory and inhibitory amino acids.
Peripheral antinociceptive effects of morphine after burn injury
Authors: MØINICHE S. , DAHL J. B. , KEHLET H.
Published: January 2009

In a double–blind study, 2 mg of morphine in saline, or saline only, was given subcutaneously into a seconddegree bilateral leg–burn injury in 12 volunteers. Heat–pain thresholds and pressure–pain thresholds were significantly increased by local morphine administration. These results confirm experimental data demonstrating a peripheral antinociceptive effects of opioids in inflamed tissue.