bluuebunny/crossref_metadata_2025 huggingface dataset:
The influence of 10 mg and 20 mg of bambuterol on the duration of succinylcholine‐induced neuromuscular blockade
Authors: Staun P. , Lennmarken C. , Eriksson L. I. , Wirén J‐E.
Published: January 2009

Bambuterol is an inactive prodrug which is enzymatically cleaved by plasma cholinesterase to yield the active compound, terbutaline. This catalytic process is accompanied by a selective inhibition of plasma‐cholinesterase, the enzyme also necessary for the break‐down of succinylcholine. We therefore studied the possible effect of bambuterol on succinylcholine‐induced neuromuscular blockade in a double‐blind fashion in patients undergoing surgery under general anaesthesia. Of the 39 patients studied, 13 patients had 10 mg of bambuterol, 12 had 20 mg and 14 were given placebo 10–16 h prior to anaesthesia. Succinylcholine 1 mg kg‐1 bw was administered after induction of anaesthesia. Following supramaximal train‐of‐four stimulation of the ulnar nerve, the tension developed in the adductor pollicis muscle was measured. Onset time and the durations of action (times to 10%, 25%, 75% and 90% recovery of the first twitch of the train‐of four response) were recorded. The mean recovery times were prolonged 30–50% in patients who had received 10 or 20 mg of bambuterol as compared with placebo. It is concluded that a prolonged duration of action of succinylcholine can be expected in patients being treated with bambuterol.
Postanaesthetic nausea in children
Authors: Karlsson E. , Larsson L. E. , Nilsson K.
Published: January 2009

The incidence of emetic episodes during the first 24 h after anaesthesia was studied prospectively in 485 children aged 0–16 years in relation to age, premedication, type of induction, type and duration of anaesthesia, type of surgery and use of postoperative analgesics. The incidence of emetic episodes was 25% in the whole material. The majority of the emetic episodes were recorded after the immediate recovery period. In children under 2 years of age, vomiting was only recorded in 5%. Nausea and vomiting was most common after squint surgery (75%) and least common after endoscopies (17%). Neither premedication with diazepam nor the method ofinduction (thiopentone, i.v., thiopentone rectally, inhalation with halothane) influenced the incidence of nausea. For the same type of surgery, maintenance of anaesthesia with halothane resulted in a lower incidence of nausea than anaesthesia with fentanyl‐pancuronium.
Non‐invasive blood pressure monitoring during head‐up tilt using the Penaz principle
Authors: Friedman D. B. , Jensen F. B. , Matzen S. , Secher N. H.
Published: January 2009

Continuous blood pressure measurement by a non‐invasive means is of clinical utility in many situations where changes in cardiovascular hemodynamics and blood volume distribution are likely to occur. We have compared blood pressure measurements using the Penaz principle (Finapres, Ohmeda) to an intra‐arterial catheter system during head‐up tilt (reverse Trendelenburg' s position) which models central hypovolemia. Twelve healthy volunteers were raised to a 60Â˚ head‐up tilt position for 60 min or until presyncope occurred. Seven subjects developed presyncopal symptoms at a mean time of 38 + 6 min with blood pressure measured by the Penaz principle falling from 140 Â± 8/72 Â± 4 to 82 Â± 10/54 Â± 6 mmHg (18.7 Â± 1.1/9.6 Â± 0.5 to 10.9 Â± 1.3/ 7.2Â±0.8 kPa) (P<0.01), at which point they were returned to a horizontal position with an immediate rise in blood pressure. During the maximal drop in blood pressure, heart rate decreased from 82 Â± 7 to 45 + 5 (P<0.01). Overall, the non‐invasive system had a correlation coefficient of 0.98 as compared to the intraarterial method and ECG for blood pressure and heart rate in all 12 subjects during rest, tilt, and recovery. We conclude that the Penaz principle apparatus is a useful monitor of symptomatic hypotension during central hypovolemia.
The maternal hemodynamic effects of bupivacaine‐epinephrine mixture used for obstetrical anesthesia
Authors: Grant G. J. , Ramanathan S. , Turndorf H.
Published: January 2009

The maternal hemodynamic effects of bupivacaine (0.5%)‐epinephrine (5 μg/ml) mixture used for lumbar epidural anesthesia were studied with an impedance cardiograph and an automated blood pressure device in term gravidas undergoing elective cesarean section. Following i.v. hydration with 2000 ml Ringer' s lactate solution, 16 patients received bupivacaine‐epinephrine mixture and 16 patients plain bupivacaine in 5‐ml increments to a T4 level. Measurements were made before anesthesia, at T10 and at T4 sensory levels. Results were analyzed using analysis of variance (ANOVA) and the least significant difference method at P<0.05. In the epinephrine group, at T10 level, the diastolic (D) and mean (M) pressures decreased significantly 11 Â± 3, and 10 Â± 1 % (mean Â± s.e.mean) respectively with no significant change in the S pressure. No significant changes were seen in the plain group. At T4, the S, D and M pressures decreased significantly 8 Â± 2, 18 Â± 4 and 16 Â± 2% in the epinephrine group. In the plain group the decrease in each one of these pressures was less than 5% and was not significant. In the epinephrine group, S, D and M pressures decreased significantly more than they did in the plain group at T10 and T4. Systemic vascular resistance decreasd significantly from control values by 19 Â± 6% at T4 in the epinephrine group with no significant changes in the plain group. No significant differences were seen in cardiac output (CO), stroke volume and heart rate (HR) in either group at T10 or T4 levels, compared to the baseline value or compared to the other group. It is concluded that epidurally administered epinephrine produces mainly a β‐2 mediated vasodilatation without any evidence of u‐agonism or changes in CO or HR.
Forty‐six “first anaesthetics” in the world
Authors: Secher O.
Published: January 2009

Data about forty‐six “first anaesthetics” have been collected from the literature. This makes it possible to get an impression of how fast the news of ether anaesthesia spread to Europe and other parts of the world. Most European countries had the news within 4 months and other parts of the world within 9 months. The use of ether seems not to have spread faster in the US than in Europe.
Patients'experiences of postoperative respirator treatment ‐ influence of anaesthetic and pain treatment regimens
Authors: HALLENBERG B. , BERGBOM‐ENGBERG I. , HALJAMÄE H.
Published: January 2009

The influences of premedication, anaesthetic agents, and postoperative sedation and pain treatment regimens on the experiences of postoperative respirator treatment of surgical patients (n= 107) have been assessed. Of the patients, 55% recalled the respirator treatment. Administration of anticholinergic drugs and halogenated anaesthetic agents was found to impair the memory process and reduce the number of recallers, and sedation in the ICU with benzodiazepines was found to decrease the number of discomforts experienced by the recalling patients. Most of the patients who received treatment postoperatively for pain, mainly by epidural administration of local anaesthetic agents and/or morphine, recalled the respirator treatment period (85%), as compared to only 50% of the patients receiving intravenous opioids. The number and type of complaints experienced by patients receiving epidural pain treatment did not, however, differ from those reported by intravenously treated patients, and no significant adverse psychological reactions seemed to occur. It is concluded that the use of mainly regional techniques, when appropriate, for pain treatment of surgical patients needing postoperative ventilatory support seems advantageous. The primary aim of relieving pain from the wound area is achieved, allowing such light intravenous sedation and pain treatment that the possibility of communication and giving comforting reassurance is maintained. Such nursing care may be more efficient in helping the patient to cope with the stressful respirator treatment situation then heavy intravenous sedation and pain treatment regimens.
Pulmonary clearance of 99mTc‐DTPA during halothane anaesthesia
Authors: Wollmer P. , Schairer W. , Bos J. A. H. , Barker W. , Krenning E. P. , Lachmann B.
Published: January 2009

We studied the integrity of the alveolo‐capillary barrier during different forms of anaesthesia by measuring the pulmonary clearance of inhaled99mTc‐DTPA. We studied four groups of rabbits. Groups I and II were anaesthetized with nembuthal only and the fractional concentration of inspired oxygen (F1O2) was 0.30 and 1.00, respectively. Groups III and IV were anaesthetized with 1% halothane and F1O2was 0.30 and 0.99, respectively.99mTc‐DTPA was administered as a fine aerosol and the clearance of the tracer from the lungs was subsequently measured with a gamma camera. The mean half‐life of the tracer in the lungs in Groups I‐IV was 60, 58, 59 and 26 min, respectively. The rapid pulmonary clearance of99mTc‐DTPA in Group IV indicates that halothane in combination with high oxygen concentration increases the permeability of the alveolo‐capillary barrier. This may be due to effects on the pulmonary surfactant system and/or the alveolar epithelium.
Haemodynamic effects of famotidine and cimetidine in critically ill patients
Authors: Omote K. , Namiki A. , Nishikawa T. , Hagiwara T. , Iwasaki H. , Tsuchida H.
Published: January 2009

To compare the cardiovascular effects of the histamine H2 receptor antagonists, famotidine and cimetidine, in critically ill patients, seven ICU patients were given 20 mg of famotidine or 200 mg of cimetidine intravenously in a randomized fashion. Each patient was studied on 2 separate days. In a random fashion, they received famotidine on one of the days and cimetidine on the other. Mean systemic arterial pressure (MAP) was maximally decreased 2 min after intravenous cimetidine from 103 ± 10 (13.7 ± 1.3 kPa) (mean ± s.d.) to 83 ± 15 mmHg (11.1 ± 2.0 kPa) (P<0.05). MAP returned to control values 8 min after administration of the drug. Systemic vascular resistance (SVR) was significantly decreased during the 8‐min observation period (P<0.01). In contrast, famotidine produced little haemodynamic effect over the 8‐min period. Therefore, we suggest that famotidine may be a better H2 antagonist than cimetidine in critically ill patients requiring vasoconstrictor drug support, since it avoids the significant decrease in systemic blood pressure and peripheral vasodilation seen after cimetidine.
The effect of bambuterol (carbamylated terbutaline) on plasma cholinesterase activity and suxamethonium‐induced neuromuscular blockade in genotypically normal patients
Authors: Bang U. , Viby‐Mogensen J. , Wirén J. E. , Skovgaard L. Theil
Published: January 2009

Bambuterol (the bisdimethylcarbamate prodrug of terbutaline) is a new bronchodilator with a prolonged duration of action due to its inhibition of plasma cholinesterase during metabolism. The effect of bambuterol on suxamethonium‐induced neuromuscular blockade was studied in 10 patients undergoing elective laparotomy. Thirty mg of bambuterol was given 2 h before anaesthesia, which was performed with thiopentone, fentanyl, halothane and nitrous oxide in oxygen. Neuromuscular function was monitored using supramaximal train‐of‐four stimulation of the ulnar nerve and a force displacement transducer. Suxamethonium 1 mg ± kg‐1 was given i.v. for endotracheal intubation. Plasma cholinesterase activity was measured before and after intake of bambuterol and during anaesthesia. The results from the 10 patients were compared with those of 41 patients not given bambuterol but otherwise studied during the same conditions. Following bambuterol, all patients had a significant decrease of plasma cholinesterase activity (P< 0.001) and the suxamethonium‐induced blockade was 3–4 times prolonged compared to patients not given bambuterol (P<0.001). Five patients with very low plasma cholinesterase activity developed a long‐lasting phase II block.
The effect of bambuterol on plasma cholinesterase activity and suxamethonium‐induced neuromuscular blockade in subjects heterozygous for abnormal plasma cholinesterase
Authors: Bang U. , Viby‐Mogensen J. , Wirén J. E.
Published: January 2009

Bambuterol is a new bronchodilator which is also a reversible inhibitor of plasma cholinesterase. In patients with normal plasma cholinesterase genotype, bambuterol prolongs suxamethonium‐induced neuromuscular blockade. In the present study, we investigated the interaction of bambuterol and suxamethonium in nine patients heterozygous for abnormal plasma cholinesterase during anaesthesia with fentanyl, thiopentone, halothane and nitrous oxide in oxygen. The patients (seven Eu1Ea1 and two Eu1Ea1) were given 20 mg of bambuterol orally 2 h before anaesthesia. Suxamethonium 1 mg ± kg‐1 was given for tracheal intubation. The neuromuscular function was monitored using train‐of‐four (TOF) stimulation of the ulnar nerve and a force displacement transducer. Plasma cholinesterase activity decreased in all patients following bambuterol (P< 0.001). In patients with genotype Eu1Ea1, median time to 90% recovery of twitch height and TOF ration ± 0.7 (37.5 min) was prolonged compared to 28 Eu1Ea1 patients not treated with bambuterol (14.0 min) (P < 0.001). Four of these patients developed a phase II block apparently not correlated to plasma cholinesterase activity. In the Eu1Ea1 patients, full recovery was seen after 22.0 and 31.4 min, respectively. It is concluded that in patients heterozygous for abnormal plasma cholinesterase, bambuterol 20 mg taken 2 h before anaesthesia causes a 2–3 times prolongation of the neuromuscular blockade following suxamethonium 1 mg ± kg‐1 and in some patients a phase II block.
The function of granulocytes and alveolar macrophages following a single dose of endotoxin in rabbits. Effects of methylprednisolone
Authors: Kjæve J. , ØSterud B. , Bjertnæs L.
Published: January 2009

It is a generally held opinion that steroids attenuate the activation of phagocytes. However, this statement has its limitations; in rabbit endotoxemia, for instance, steroids enhance the procoagulant activity of mono‐cytes. The present study aimed to investigate the release of toxic oxygen metabolites (TOM) from granulocytes and alveolar macrophages 24 h after endotoxin injection in rabbits, and the effect of concomitant injection of methylprednisoione (MP). Release of TOM was assessed by peak chemiluminescence (CLP). Expression of thromboplastin activity by alveolar macrophages was determined as well, employing a recognized method for assessment of activity. In terms of mean ± s.e.mean, endotoxin increased granulocyte count from a baseline value of 1.8 ± 0.2 × 105 cells/ml to 3.7 ± 1 × 106 cells/ml, which increased further to 9.8 ± 2.5 × 106 cells/ml following administration of MP. Whereas endotoxin given alone caused no significant change in granulocyte CLP, additional administration of MP increased CLP from 1723 ± 389 to 16610 ± 8428 counts. On the other hand, MP attenuated an endotoxin‐induced increase in both CLP and thromboplastin activity of alveolar macrophages. Thus, MP appears to have a proinflammatory effect on circulating granulocytes in rabbit endotoxemia, simultaneously depressing the function of stationary macrophages. This may suggest an injurious effect of MP in rabbit endotoxemia.
Biological correlates of mental stress related to anticipated caesarean section
Authors: Scheinin M. , Scheinin H. , Ekblad U. , Kanto J.
Published: January 2009

The relationships between self‐reported assessments of acute anxiety and several biochemical and physiological indicators of stress reaction were investigated in pregnant women at term in connection with spinal analgesia for caesarean section. Fear and apprehension were statistically significantly associated only with blood pressure and with an increase in heart rate from the previous daty. The subjective estimate of the quality of the preoperative night's sleep was negatively associated with biochemical plasma and cerebrospinal fluid (CSF) measures of sympatho‐adrenal activity. The previously reported negative correlation between body height and 5‐hydroxyindoleacetic acid (5‐HIAA, an indicator of serotonin metabolism) in lumbar CSF was confirmed. The concentration of 5‐HIAA in CSF was positively correlated with the levels of other acidic monoamine metabolites and cortisol in CSF. It is concluded that hormone and monoamine metabolite measurements in CSF and plasma have only limited usefulness as quantitative indicators of the intensity of preoperative fear and anxiety.
Influence of salbutamol on the in vitro muscle response to caffeine and halothane in malignant hyperthermia
Authors: Bendixen D. , ØRding H.
Published: January 2009

In vitro contracture tests for susceptibility to malignant hyperthermia (MH) were performed with halothane and caffeine in 34 patients, according to the protocol of the European MH Group. Additional halothane and caffeine tests were performed in the presence of salbutamol 50 μg/I. Contractures after exposure to halothane were seen only in MH‐susceptible (MHS) patients (n= 16), and were not changed by salbutamol. Salbutamol did not influence the caffeine dose‐response curves in any of the groups (n=14 in the MH‐non‐susceptible (MHN) group). The caffeine threshold concentration was significantly increased by salbutamol in the MHS group.
Pressure pain thresholds in volunteers and herniorrhaphy patients
Authors: Dahl J. B. , Rosenberg J. , Jensen F. Molke , Kehlet H.
Published: January 2009

Pressure algometry is a method to estimate pressure pain sensitivity in tissues. The aim of the present study was to evaluate the reproducibility of pressure pain thresholds (PPT) in the abdominal integument and to evaluate the use of pressure algometry as a measure of wound tenderness following surgery. PPT was determined in 20 healthy volunteers on two separate examinations, and in 14 patients at the incisional site before and following inguinal herniotomy. In volunteers, PPT was higher for men than for women, and no difference was observed between the first and second day of examination. In surgical patients a significant decrease in PPT was observed following operation. Morphine 0.07 mg/kg caused a slight but significant increase in PPT. Pressure algometry may be useful to study nociceptive mechanisms and the dynamics of wound pain in surgical patients.
The role of sympathetic activity in initiating malignant hyperthermia
Authors: Häggendal J. , Jönsson L. , Carlsten J.
Published: January 2009

The role of sympathetic activity in triggering malignant hyperthermia (MH) is controversial. Increased sympathetic activity has been considered by some to be the causal factor, whilst others believe this activity to be secondary to metabolic events in the MH syndrome. In this study, a number of parameters, including the blood levels of noradrenaline and adrenaline, were followed in pigs susceptible to MH during exposure to halothane. Seven pigs, crossbreeds of Swedish Landrace and Yorkshire, females and castrated males, aged about 9 months were used. Results are presented for individual pigs. One of the pigs was a nonresponder. The time of onset for different signs of MH varied greatly, as judged by ten independent observers. Onset of changes in heart rate, muscle temperature, blood Pco2 and pH, plasma adrenaline and noradrenaline could be scored. The metabolic events (increased Pco2 and decreased pH in blood) significantly preceded the signs of increased sympathetic activity (increased heart rate and elevated levels of catecholamines in blood). Our results support the view that increased sympathetic activity does not initiate MH. The sympathetic activity, however, strongly contributes to the fulminant MH syndrome.
Pharmacology of Dormicum (midazolam) and Anexate (flumazenil)
Authors: Amrein R. , Hetzel W.
Published: January 2009

Midazolam and flumazenil have some characteristics in common which make them suitable partners as benzodiazepine (BZD) agonist and antagonist. After intravenous (i.v.) administration, both drugs are rapidly distributed into similar distribution volumes, from which they are cleared with a comparable short climination half‐life (t1/2β) in the range of 1 h (flumazenil) to 3 h (midazolam). Both drugs undergo hepatic metabolisation with a relatively high hepatic extraction ratio of around 0.3 for midazolam and 0.6 for flumazenil. The metabolisation of midazolam and flumazenil may equally be affected by considerable loss of active liver cells or by temporarily reduced hepatic blood flow. In such a case, elimination of both drugs may be prolonged in the same way. Flumazenil has only an inactive metabolite. The main active α‐hydroxy‐metabolite of midazolam does not contribute much to the activity of midazolam after parenteral administration. Its potency is lower than that of midazolam and its shorter elimination half‐life (0.8 h) does not prolong the activity of the parent drug. As indicated by the therapeutic index, both drugs have a very high safety margin, which is considerably higher than that of thiopentone or propofol. Only low doses of both drugs are necessary to produce initial effects. Increasing doses intensify the drug activity and a ceiling effect is observed after maximal doses of midazolam and flumazenil. The onset of effect immediately follows the diffusion of the substances into the CNS and can be observed within the first minutes following flumazenil or midazolam administration. The rapid onset of effect allows both drugs to be administered in repeated small bolus doses under close observation of the patient's reaction. This titrated administration allows one to consider the individual requirements of the patient, his age, and physical condition. The titration method not only allows the optimisation of the drug's effect in each patient but also contributes to tolerability and minimisation of adverse events.
The use of midazolam and flumazenil in diagnostic and short surgical procedures
Authors: Whitwam J. G.
Published: January 2009

Benzodiazepines, used correctly, provide a relatively safe means of providing sedation in a variety of clinical situations and midazolam, which is shorter acting than other benzodiazepines (BZ), is the drug of choice in ambulatory patients. Flumazenil is a highly effective specific competitive BZ antagonist which provides a safe means of rapidly attenuating or terminating BZ sedation. Its mean half‐life is 54 min, and in this contact the optimal dosage is 0.2 to 0.5 mg. Although it reverses sedation and amnesia, there is still a question about whether its efficacy in reversing the respiratory depressant effects of benzodiazepines is adequate. This remains an area of critical debate, as does resedation and also its administration to chronic benzodiazepine users. The use of flumazenil to reverse midazolam‐induced sedation introduces, for the first time, the possibility of terminating sedation at a predetermined time. Were it to be adopted routinely, it has major implications for the improvement of patient management affecting all aspects of post‐operative care.
The use of midazolam and flumazenil in locoregional anaesthesia: an overview
Authors: Halim B. , Schneider I. , Claeys M. A. , Camu F.
Published: January 2009

Midazolam is useful as an intravenous supplement to local anaesthesia techniques in producing sedation, amnesia and anxiolysis, and has about five times the sedative potency of diazepam. Considerable interpatient variability exists in dose requirements, especially in elderly patients. The combined effects of local anaesthetics and midazolam may contribute to enhanced haemodynamic effects and changes in the respiratory pattern, impairing ventilation and oxygenation. Flumazenil can be titrated in incremental doses to reverse the residual sedative effects of midazolam, without intrinsic haemodynamic or respiratory effects, but may not fully antagonise the decrease in chemoreceptor sensitivity nor the changes in breathing pattern induced by midazolam. Patients treated with epidural or spinal anaesthesia supplemented with midazolam should be monitored to avoid hypoxaemia risks even after the administration of flumazenil.
The respiratory effects of reversing midazolarn sedation with flumazenil in the presence or absence of narcotics
Authors: Weinbrum A. , Geller E.
Published: January 2009

The purpose of this study was to determine the effects of reversal of sedation with flumazenil (F), in the presence or absence of opiates, on arterial oxygen saturation (Sao2) and cnd‐tidal CO2 (ETco2). Twenty‐four patients undergoing surgery and epidural anaesthesia were studied. Twelve patients (Group A) were orally premedicated with diazepam and 0.1 mg·kg‐1 morphine i.m. Intraoperative sedation consisted of midazolam 0.1 mg·kg‐1 and pethidine 0.7 mg·kg‐1 i.v. Twelve patients (Group B) were premedicated with diazepam and sedated intraoperatively with 0.1 mg·kg‐1 midazolam. In the recovery room, six patients in each group were randomly allocated to receive 1 mg of flumazenil while the others were allowed to awaken spontaneously (control). Sedation (eyes open vs closed), Sao2, ETco2, respiratory rate, blood pressure and pulse were non‐invasively monitored for 90 min. Administration of flumazenil resulted in a statistically significant increase in the number of patients with eyes open in both groups at 5 min, lasting 15 min in Group A and 30 min in Group B patients. An increase in Sao2 from 15–45 min after injection of flumazenil was observed only in Group B. No significant difference between groups in any other parameter was found. We concluded that reversal of benzodiazepine (BZ) sedation with flumazenil improved Sao2 in patients sedated with only BZ; in the presence of BZ and opiates, flumazenil did not affect respiratory parameters.
The use of midazolam in premedication
Authors: Lindahl S. G. E.
Published: January 2009

Socio‐psychological factors, such as increased anxiety in developed societies and cultures, and separation anxiety, particularly in children, justify the use of premedicants. In addition, the link between a central nervous “anxiety centre” and biochemical stress responses is blocked by an efficient anxiolytic. The elimination half‐life of midazolam is longer in the elderly than in the young and in the obese than in the thin, which demands longer intervals between repeated doses in old and fat patients. The hypoxic ventilatory response is depressed in most patients and the ventilatory CO2 response in patients with chronic pulmonary disorders, which justifies increased monitoring of O2 saturations. It is important for the choice of dose and for estimating the duration of recovery time to know that midazolam is at least four times as potent as diazepam.
Methohexital vs midazolam/flumazenil anaesthesia during laryngoscopy under jet ventilation
Authors: Kulka P. J. , Lauven P. M. , Schüttler J. , Apffelstaedt C.
Published: January 2009

In a randomised clinical study, two total intravenous anaesthesia techniques for microlaryngoscopic laser surgery were compared. After an induction dose of 100 mg methohexital, Group I received a maintenance infusion of 10 mg·min‐1. In Group II anaesthesia was obtained by 15 mg midazolam followed by 0.1 mg·min‐1 continuously and terminated by the injection of flumazenil. For analgesia 5 mg alfentanil were administered. Opiate‐induced respiratory depression was antagonised by 0.08 to 0.12 mg naloxone. Prior to, during, and after surgery, adrenergic response was assessed by HPLC‐analysis of blood taken from a peripheral vein. Haemodynamic responses to the operation and during the post‐operative period were almost identical in both groups. In Group I, the mean recovery period of 14 min was significantly longer than in Group II (9 min), where patients received a mean dose of 0.53 mg (0.15) flumazenil. Resedation could be observed in all patients receiving flumazenil within 60 min after antagonisation, which was associated with a mean decrease in O2‐saturation from 95% to 88%. There was no difference in epinephrine and norepinephrine blood levels between the two groups prior to and during anaesthesia. In all patients, arousal was associated with a significant increase in the epinephrine plasma concentration. While blood levels in Group I decreased during the post‐operative period to levels prior to surgery, the concentrations in Group II remained elevated. In one patient who received no naloxone, the reversal of midazolam action induced a 16‐fold increase in catecholamine levels (from 50 to 800 ng.1‐1) associated with a tachycardia of 170 b·min‐1 and hypertension of 160 mmHg. It is concluded that both anaesthetic techniques provide appropriate and equivalent anaesthesia for laryngeal surgery under jet ventilation. The shorter post‐operative period of unconsciousness after flumazenil administration can be regarded as an advantage. Yet, in single cases the use of flumazenil may lead to excessive adrenergic reactions combined with tachycardia and hypertension. This has to be considered when the antagonist is administered to high‐risk patients. The higher degree of post‐operative vigilance is less accepted by some patients. Post‐operative observation after antagonisation is mandatory as resedation may result in hypoxic episodes.
Postoperative sedation with midazolarn in heart surgery patients: pharmacokinetic considerations
Authors: Maitre P. O.
Published: January 2009

Midazolam remains one of the few drugs that can safely be used for the sedation of intubated patients in an intensive care unit. Midazolam pharmacokinetics in patients recovering from cardiac surgery were recently reported and found to be different from the drug's kinetics in young and healthy patients or volunteers. In particular, the elimination half‐life was prolonged (10.6 h) and the metabolic clearance was reduced. For the clinician, pharmacokinetics parameters do not have a straightforward meaning. The purpose of the present paper is to review the pharmacokinetics of midazolam in this category of patients, and to examine what kind of practical information and dosing recommendation can be derived.
Deadspace during anaesthesia
Authors: Fletcher R.
Published: January 2009

Deadspace is defined in terms of the efficiency of the lung in eliminating carbon dioxide. The airway deadspace is the volume of the airway in which gas moves chiefly by convection. The alveolar deadspace is caused by ventilation/perfusion inequalities at the alveolar level. The commonest causes of increased alveolar deadspace are airways disease ‐ smoking, bronchitis, emphysema, and asthma. Other causes include pulmonary embolism, pulmonary hypotension, and ARDS. In addition, right‐to‐left shunting (cyanotic heart disease, atelectasis) causes an apparent or virtual deadspace, which, although not representing non‐perfusion of any compartment, nevertheless reduces the efficiency of ventilation.
A quantitative double‐blind evaluation of the antinociceptive effects of perineurally administered morphine compared with lidocaine
Authors: ARENDT‐NIELSEN L. , BJERRING P. , DAHL J. BERG
Published: January 2009

In two double‐blind, placebo‐controlled investigations, morphine and lidocaine were administered perineurally to the ulnar nerve. Thresholds (warmth and pain) and pain‐evoked brain potentials (amplitude and latency) to argon laser stimulation were measured up to 120 min after the injection. Hypalgesia to laser pain was detected 15 min after the injection of morphine and 5 min after the injection of lidocaine. The duration of hypalgesia and analgesia was less than 15 min for morphine and 85 min for the lidocaine injection. Both morphine and lidocaine increased the latency of the brain potentials, which indicates that the same blocking mechanisms could be involved. Pin‐prick analgesia was obtained 5 min after the injection of lidocaine, but 15–30 min elapsed before the laser pain was inhibited maximally. Laser pulses can activate larger skin areas than needle pricks, indicating that a central summation of the activity from many cutaneous nociceptors is important in order to obtain a reliable indicator of adequate analgesia.
Percutaneous placement of permanent central venous catheters: experience with 200 catheters
Authors: WISBORG T. , FLAATTEN H. , KOLLER M.‐E.
Published: January 2009

The prospective registration of 200 percutaneous placements of permanent central venous catheters (Hickman catheters and subcutaneous infusion ports) was conducted in 172 patients aged 3 months‐95 years. The insertions were reviewed to assess whether certain groups of patients or physicians were associated with more complications than others. Complications occurred in 16 patients (8. 0%), of which 12 were arterial punctures. Two attempts (1%) at catheter placement failed. None of the complications required treatment. Of the catheter placements, 70% were performed by one of the three authors, and the rest by seven other experienced anesthesiologists. The complication rates were not different between the two groups. Nor was the complication rate significantly higher in small children. Percutaneous placement of permanent central venous catheters thus proved to be a safe and reliable technique, even in small children. The method is easily learnt by physicians experienced in central venous catheterization. Using this method, permanent venous access may be offered to a large number of patients.
Toxic oxygen metabolites induce vasoconstriction and bronchoconstriction in isolated, plasma‐perfused rat lungs
Authors: KjÆVE J. , VAAGE J. , BJERTNÆS L.
Published: January 2009

Effects of toxic oxygen metabolites (TOM) on the pulmonary vascular bed and airways were studied in isolated, plasma‐perfused rat lungs. TOM were generated by xanthine oxidase (XO) (0. 1 or 0. 25 unit– ml‐1) and hyopxanthine (HX) (1 mol. l‐1). In vitro measurements by chemiluminescence indicated that the major oxygen metabolite generated by XO and HX was H2O2. Measurements of Po2 in the perfusate as an indicator of O2–consumption suggested that production of TOM by XO and HX was finished, within 30 min. XO and HX induced an early dose‐dependent bronchoconstriction and a late increase in transpulmonary pressure (Ptp). Pulmonary arterial pressure (Ppa) increased gradually and levelled off within 30 min with low‐dose XO, but not with high‐dose XO. As judged by weight increase of the lungs, interstitial edema occurred regularly. Allopurinol, an inhibitor of XO, blocked the lung responses caused by XO and HX. Catalase attenuated all lung responses induced by XO and HX, while superoxide dismutase had no effect. The hydroxyl radical scavenger dimethylsulfoxide abolished the increase in Ptp and attenuated the increase in Ppa, but did not consistently protect the lungs from edema development. This study shows that TOM induce vasoconstriction, bronchoconstriction and lung edema in plasma‐perfused rat lungs, mainly due to generation of H2O2 and the hydroxyl radical.
The effects of a 16‐N‐homopiperidino analogue of vecuronium on neuromuscular transmission in anaesthetized cats, pigs, dogs and monkeys, and in isolated preparations
Authors: MUIR A. W. , ANDERSON K. , MARSHALL R. J. , BOOIJ L. H. D. J. , CRUL J. F. , PRIOR C. , BOWMAN W. C. , MARSHALL I. G.
Published: January 2009

Org 9991, a 16‐N‐homopiperidinium substituted vecuronium analogue, has been tested for neuromuscular blocking activity in anaesthetized cats, pigs, dogs and monkeys, and in isolated nerve‐muscle preparations. Org 9991 exhibited non‐depolarizing neuromuscular blocking activity of the competitive type, being reversible by neostigmine and showing no endplate channel blocking action in isolated preparations. In cats, 50% vagal block was observed at doses of Org 9991 approximately 10 times those producing 50% neuromuscular block; no ganglion block was seen at these doses. Effects on blood pressure or heart rate at 90% twitch blocking doses were either minor or absent. The potency and time course of action of Org 9991 remained similar in all four species: i. e. 90% block at ca 200–300 μg kg‐1; onset time ca 1. 2–1. 9 min; duration 90% ca 4. 5–8. 9 min. This study suggests that 16–N‐homopiperidinium analogues of vecuronium may provide leads in the quest for a potent non‐depolarizing replacement for suxamethonium.
Spinal epidural hematoma following epidural anesthesia versus spontaneous spinal subdural hematoma. Two case reports
Authors: Metzger G. , Singbartl G.
Published: January 2009

Two cases of lumbar hemorrhage with subsequent persistent neurologic sequelae are presented and their possible causes are discussed in the context of a literature review: one patient with spontaneous spinal subdural hematoma with no trauma or lumbar puncture and one with spinal epidural hematoma associated with preceding epidural catheterization for postoperative pain relief. The subdural hematoma was associated with a thrombocytopenia of about 90000/μl due to intraoperative blood loss. This might have been contributory to the formation or expansion of the hematoma, but it is not convincing since a platelet count of this amount should not lead to spontaneous bleeding. Both patients received low‐dose heparin, but since coagulation tests were normal, prolonged bleeding does not appear to be a likely cause, although it cannot be excluded. In conclusion, the reasons for both hematoma remain unclear. With regard to the epidural hematoma and low‐dose heparinization, the possible coincidence of spontaneous lumbar hematoma and lumbar regional block should be taken into consideration.
Effect of upper abdominal surgery and cirrhosis upon the pharmacokinetics of methohexital
Authors: Duvaldestin P. , Chauvin M. , Lebrault C. , Bertrand F. , Karolak F. Tamisier , Farinotti R.
Published: January 2009

The pharmacokinetic profile of methohexital was studied in cirrhotic patients (n = 8), patients undergoing upper abdominal surgery (n = 8) and orthopaedic patients under general anaesthesia (n = 8). The total plasma clearance of methohexital was unchanged in cirrhotics: 54 ± 22 I‐h‐1 (mean±s.d.) as well as in patients undergoing upper abdominal surgery: 60 ± 14 I‐h‐1 in comparison to orthopaedic surgery: 70 ± 24 I‐h‐1. The central volume and total volume of distribution and the distribution and elimination half‐lives were similar between the three groups. Despite its hepatic dependent elimination, methohexital elimination kinetics were unchanged in patients undergoing upper abdominal surgery and in cirrhosis. Owing to the high hepatic extraction ratio of methohexital, its elimination should be influenced by the hepatic blood flow. The unchanged elimination kinetics presently observed in patients with cirrhosis or those undergoing upper abdominal surgery suggest that the hepatic blood flow is less diminished than expected in these patients.
Metabolic gas exchange during aortocoronary bypass surgery using a double pump systemand mechanical ventilation
Authors: Svensson K. L. , Henriksson B.‐A. , Sonander H. G. , Stenqvist O.
Published: January 2009

Oxygen uptake and carbon dioxide excretion during aorto‐coronary bypass surgery were studied in seven patients by indirect calorimetry and compared to blood‐gas based measurements. Medium‐high dose fentanyl, droperidol and midazolam were used for maintaining anaesthesia. During the period of extracorporeal circulation no external oxygenator was used. Circulation was maintained by two pumps by‐passing the left and right heart respectively and the patient's lungs were ventilated with O2/N2 using a Servo 900C ventilator. For indirect calorimetric measurements gas concentrations were analysed by Beckman instruments and gas volumes were measured by the Servo 900C ventilator. Oxygen uptake and carbon dioxide excretion decreased by 31% and 39%, respectively. For invasive measurements during extracorporeal circulation, arterial and venous blood gases and pump flow were used. Using pump flow instead of cardiac output when calculating oxygen uptake circumvented errors in thermodilution measurements. There was a good correlation (r = 0.88) between the invasive and the indirect calorimetric measurements. Further, there was a good correlation between naso‐pharyngeal temperature and indirect calorimetric measurements of oxygen uptake (r = 0.87).
Interactive effects of isoflurane and amrinone in the feline intestinal and renal circulation
Authors: Raner C. , Biber B. , Martner J. , Winsö O.
Published: January 2009

Interactive effects of the phosphodiesterase‐III inhibitor amrinone and isoflurane were investigated in cats. Cardiac output (thermodilution method), and intestinal (IBF) and renal (RBF) blood flows (optical flowmetry) were measured. Intestinal (IVR) and renal (RVR) vascular resistances were derived. To discriminate between pressure‐related local myogenic vascular responses and primary vascular drug effects, intestinal and renal perfusion pressures (50 mmHg; 6.7 kPa) were controlled. The protocol included steady‐state recordings with and without isoflurane in a randomized order, both before and after the administration of amrinone (2 mgkg‐1i.v. + 2 mgkg‐1i.v.). Amrinone induced no significant changes in IVR or RVR during basal chloralose anesthesia. During administration of 0.8% isoflurane, amrinone produced decreases in IVR and RVR, which were more pronounced than the vasodilator responses induced by this dose of isoflurane alone. On the other hand, with 1.6% isoflurane, amrinone did not add to the vasodilation. The cardiac effects of isoflurane and amrinone were small. Our data indicate that the vascular tone before administration of amrinone could be crucial for the vascular response of the drug and that isoflurane can significantly influence the regional circulatory effects of amrinone.
Effect of intradermal injection of saline or a local anaesthetic agent on skin blood flow – a methodological study in man
Authors: Cederholm I. , Evers H. , Löfström J. B.
Published: January 2009

The influence of intradermal needle insertion and fluid injection on skin blood flow was investigated using laser Doppler flowmetry. Seventeen healthy, young male volunteers participated. Four test sites on each forearm (volar surface) were used in a randomized, double‐blind study. Recordings were made at 20, 40, 60 and in GroupIIIalso at 90 min after needle insertion or intradermal injection. In GroupI(n = 6) different volumes of saline (0.05, 0.1, 0.2, 0.3 and 0.5 ml) were injected, producing an increase in flow, there being no differences between the various volumes. In GroupII(n = 4) needle insertions were made using different needle sizes (20 G, 23 G and 30 G), the larger ones being impractical to use. Increases in flow were seen, and were somewhat higher for the larger needles. GroupIII(n= 12) was studied regarding the effects of three local anaesthetic agents on skin blood flow (0.1 ml, 30 G needle). Injection of bupivacaine 0.75d̀ produced a marked increase in flow, similar to lidocaine 1% but apparently longer lasting. Bupivacaine 0.25% caused less increase in flow, similar to the flow seen with saline. Injections of ropivacaine 0.75d̀ and 0.25%, i.e. in clinical concentrations, caused a decrease in blood flow, this being most marked after 0.25d̀, indicating a unique flow‐decreasing effect of this new local anaesthetic drug.
Myocardial effects of adenosine‐ and sodium nitroprusside‐induced hypotension: a comparative study in patients anaesthetized for abdominal aortic aneurysm surgery
Authors: Öwall A. , Sollevi A.
Published: January 2009

The effects of adenosine and sodium‐nitroprusside (SNP) on central and myocardial haemodynamies and metabolism were evaluated during fentanyl anaesthesia (100 μg kg‐1) in six patients with peripheral vascular disease. The investigation was performed during stable anaeshtesia, before scheduled abdominal aortic graft surgery. Adenosine and SNP were infused intravenously in random order over 20 min, leaving a 30‐min control period in between. The vasodilators were titrated in order to reduce mean arterial pressure by approximately 25%. Adenosine (90 20 μgkg‐1 min‐1) reduced mean arterial pressure from 10.9 0.3 to 8.4 0.4 kPa (82 3 to 63 3 mmHg), and SNP (0.7 0.1 μg kg‐1 min‐1) from 11.0 0.2 to 8.4 0.3 kPa (83 3 mmHg to 63 3 mmHg) during the hypotension period. Cardiac index remained unaffected during induced hypotension with both vasodilators, while heart rate increased during SNP infusion (8 3d̀) and remained unaffected with adenosine. Left ventricular stroke work index and myocardial oxygen consumption decreased during SNP infusion (33 3% and 17 5%, respectively), while these parameters were unchanged with adenosine. Adenosine hypotension increased coronary sinus flow 1–2 fold (128 26%), together with increased coronary sinus oxygen content (96 11%). In contrast, coronary sinus flow decreased during SNP hypotension (– 15 4%) with unaffected coronary sinus oxygen content. It is concluded that adenosine, in contrast to SNP, is associated with a hyperkinetic myocardial circulation.
Plasma vitamin E, total lipids and myeloperoxidase levels during spinal surgery. A comparison between two anesthetic agents: propofol and isoflurane
Authors: Hans P. , Canivet J.‐L. , Pincemail J. , Muller J.‐P. , Byttebier G. , Lamy M.
Published: January 2009

Plasma levels of vitamin E (Vit. E), total lipids (TL), Vit. E to TL ratio and myeloperoxidase (MPO) were studied in 20 patients undergoing lumbar spinal surgery and randomly allocated to two anesthetic groups: propofol (bolus dose + continuous infusion) and thiopental/isoflurane. Peripheral blood samples were withdrawn prior to induction, each hour during anesthesia and 1 h after the end of surgery. Mean Vit. E and TL levels as well as mean Vit. E to TL ratios remained in the normal range over the entire period of study whatever the anesthetic regimen. MPO levels rose significantly in the post‐operative period only, but without statistical difference between the two groups. Therefore, anesthesia with propofol or thiopental/isoflurane modifies neither total lipid concentrations nor plasma Vit. E, which is a potent endogenous inhibitor of lipid peroxidation bound to lipoproteins. The rise of plasma MPO suggests a moderate post‐operative neutrophil activation which is not influenced by anesthetic techniques.
The independent metabolic effects of enflurane anaesthesia and surgery
Authors: Carli F. , Elia M.
Published: January 2009

The metabolic effects of enflurane anaesthesia (IMAC) in air/oxygen were investigated in six healthy unpremedicated women scheduled for total abdominal hysterectomy (TAH). The changes in acid‐base status, CO2 production, and circulating concentration of total protein, albumin and a variety of metabolites (glucose, lactate, glycerol and alanine) were measured before and during a 2‐h period of anaesthesia alone, during 1 h of anaesthesia plus surgery, and in the recovery period. The subjects were maintained normothermic (36.5 ± 0.3°), and with an arterial Sao2 above 95% throughout the period of study. The circulating concentration of all metabolites changed little as a result of anaesthesia alone, but the glucose and lactate levels rose rapidly after the onset of surgery (P<0.05). Plasma albumin and total protein concentration decreased during the study, reaching values that were significantly lower than the pre‐anaesthetic values (P<0.05). CO2 production decreased by 9% during anaesthesia and surgery, but returned towards preoperative values during recovery. This study provides no evidence of any significant effect of enflurane anaesthesia alone on human intermediary metabolism. Most of the changes in circulating metabolite concentrations observed during and after anaesthesia and surgery are likely to be due to the surgical stress.
Bradycardia associated with insertion and inflation of tissue expanders under the scalp
Authors: Francis G. A. , Jayarajah M.
Published: January 2009

A case of bradycardia during the insertion and inflation of tissue expanders under the scalp on two separate occasions is described. The possible mechanisms of this complication are discussed.