bluuebunny/crossref_metadata_2025 huggingface dataset:
Postganglionic sympathetic nerve activity in halothane–anaesthetized rats during controlled and spontaneous ventilation
Authors: Delle M. , Thorén P. , Sonander H. , Majcherszyk S. , Ricksten S. E.
Published: January 2009

The aim of the study was to compare the effect of halothane anaesthesia on sympathetic nerve discharge in mechanically normoventilated and spontaneously breathing rats. Renal sympathetic nerve activity (rSNA), mean arterial pressure (MAP) and heart rate (HR) were measured in the conscious state and at the inspiratory halothane concentrations of 0.6%, 1.2% and 2.4% in one mechanically normoventilated and one spontaneously breathing group, while a third group was subjected to controlled hypoventilation at 1.2% halothane concentration. Halothane in blood was determined in two separate groups at 1.2%. In an additional group of spontaneously breathing rats, Paco2 was analysed during consciousness and the halothane concentrations of 1.2% and 2.4%. There was a pronounced decrease in rSNA, MAP and HR at all levels of anaesthesia in the mechanically ventilated rats. However, rSNA, HR and MAP were significantly higher in the spontaneously breathing rats at increasing levels of halothane anaesthesia. Controlled hypoventilation at 1.2% halothane increased the variables significantly. In spontaneously breathing animals, Paco2 increased significantly during the halothane exposure. The concentration of halothane in blood was significantly higher in the spontaneously breathing rats. Thus, the halothane–induced respiratory depression in the spontaneously breathing rats preserved rSNA during halothane anaesthesia, possibly via CO2mediated chemoreceptor stimulation.
Fluctuating PEEP versus conventional PEEP in diffuse and unilateral lung injury induced by oleic acid
Authors: Uchida H. , Inaba H. , Sato J. , Sakurada M. , Mizuguchi T.
Published: January 2009

Effects of fluctuating positive end–expiratory pressure (F–PEEP), in which end–expiratory pressure (EEP) was periodically changed from 0.5 to 1.5 kPa with a periodic time of 6 min, and conventional PEEP (CPEEP) with a fixed EEP of 1.0 kPa, were comparatively studied in diffuse (Group 1) and unilaterally dominant lung injury (Group II). Although F–PEEP produced cyclic alterations of Pao2 in both groups, Pao2 changed in proportion to EEP in Group I and in reciprocal proportion to EEP in Group II. There was no significant difference between Pao2 and Qs/Qj during F–PEEP and those during C–PEEP in Group I, whereas in Group II, F–PEEP produced a significantly greater improvement of pulmonary oxygenation at the low EEP phase than C–PEEP. In both groups, the degree of hemodynamic depression was proportional to EEP. These results suggest that F–PEEP should be indicated for acute hypoxic respiratory failure with uneven distribution of lung injury.
Minitracheotomy in the treatment of postoperative sputum retention and atelectasis
Authors: Pedersen J. , Schurizek B. A. , Melsen N. C. , Juhl B.
Published: January 2009

Minitracheotomy (MT) is a new method for the treatment of sputum retention and atelectasis. Through a I–cm incision in the cricothyroid membrane (coniotomy), a specially designed tube is placed in the trachea, allowing suction to be performed. Fifteen patients, aged 37–78 years (median 62 years), with postoperative sputum retention, atelectasis and imminent respiratory failure, were treated with suction by MT. Thirteen of the patients recovered from their respiratory problems, while two patients had to be treated with intermittent positive pressure ventilation (IPPV). During insertion, one case of external bleeding and one–case of subcutaneous and mediastinal emphysema were seen, while no complications were seen during cannulation. The duration of cannulation was 4–38 days (median 10 days). Following decannulation the incisions were airtight within 1 day and healed within 3 days. Ten patients left hospital in good health and five died because of surgical complications and/or cardiovascular failure. MT seems to be effective in the treatment of sputum retention and atelectasis. Advantages over other invasive methods make it a method of first choice. The method involves few complications and is often so effective that avoidance of intubation and IPPV is possible.
Successful treatment of dural puncture headache with epidural saline infusion after failure of epidural blood patch
Authors: Stevens R. A. , Jorgensen V. N.
Published: January 2009

A case is presented of a 30–year–old female with a 4–month history of post–lumbar puncture headache (PLPHA) resulting from an accidental dural puncture during an attempted epidural anesthetic for cesarean section. Epidural blood patches were attempted at 4 days and 3 months post–lumbar puncture, but were unsuccessful. At 4 months post–lumbar puncture, a 24–h epidural saline infusion relieved the PLPHA for 48 h, but the headache returned. Finally, a second epidural saline infusion was done, followed by an epidural blood patch, which permanently cured the PLPHA. Follow–up to 4 months showed no return of the PLPHA. The rationale for epidural blood and saline patches is discussed.
Neostigmine and edrophonium as antagonists of atracurium and pancuronium
Authors: Sanfilippo M. , Vilardi V. , Fierro G. , Rosa G. , Pelaia P. , Gasparetto A.
Published: January 2009

Edrophonium 0.5 mg/kg or neostigmine 0.04 mg/kg were administered to two groups of 30 patients each for antagonism of atracurium– or pancuronium–induced neuromuscular block at 25% single twitch recovery. Neuromuscular block was studied using both single twitch and train–of–four (TOF) nerve stimulation. The times to 100% single twitch recovery were significantly more rapid for patients receiving edrophonium (P < 0.01) in both groups (atracurium and pancuronium); the TOF ratios were similar for atracurium, but for pancuronium they were greater after neostigmine than after edrophonium, and only at 25 min were these ratios similar. It is concluded that edrophonium in a dose of 0.5 mg/kg antagonizes neuromuscular blockade induced by atracurium, as does neostigmine in a dose of 0.04 mg/kg, but the former does not consistently antagonize neuromuscular blockade induced by pancuronium even at 25% of single twitch recovery.
Effects of the benzodiazepine antagonist flumazenil on postoperative performance following total intravenous anaesthesia with midazolam and alfentanil
Authors: Nilsson A. , Persson M. P. , Hartvig P.
Published: January 2009

Postoperative performance following total intravenous anaesthesia (TIVA) using midazolam and alfentanil was studied with and without the administration of a single dose of a benzodiazepine antagonist, flumazenil (Ro 15–1788). Performance was compared with a reference group anaesthetized with thiopentone, alfentanil and nitrous oxide. All patients were assessed by use of a rating scale which took into account the degree of sedation, amnesia, comprehension and cooperation as well as temporal and spatial orientation. There was a slow recovery following TIVA with somnolence and amnesia lasting several hours. Administration of flumazenil 1.0 mg i.v. at extubation caused a significant reduction of sedation (P<0.001) during the first postoperative hour, with patients fully awake or only lightly sedated, but was later followed by resedation. The patients of the reference group were moderately sedated during the observation period. Five and six hours postoperatively there was no difference between the groups. Amnesia was more profound in the groups that received midazolam; the effect of the antagonist could only be seen for 15 min after its administration. Comprehension and cooperation, as well as orientation, were equally good in the antagonist and in the reference group during the immediate postoperative period, whereas in the TIVA group a gradual improvement over the first hours was seen. In the antagonist group there was no increase in the number of analgesic requirements, no anxiety attacks or other adverse effects. It is concluded that flumazenil offers an improvement in postoperative performance following TIVA induced by midazolam and alfentanil, but the effects are of short duration.
Double–blind comparison of transdermal scopolamine, droperidol and placebo against postoperative nausea and vomiting
Authors: Tigerstedt I. , Salmela L. , Aromaa U.
Published: January 2009

Since transdermal scopolamine (TS) seems effective against seasickness, we compared its antiemetic effect with intravenous droperidol (DHBP), our routine antidote for postoperative emesis. Ninety–six female patients (ASA I–II) scheduled for short–stay surgery were randomly allocated to three study groups after giving their informed consent. The three groups were as follows: TS adhesive, delivering 140 μg initially and 5 μg/h thereafter + placebo 0.5 ml i.v. 5 min before the end of surgery; transdermal placebo adhesive preoperativcly + DHBP 0.5 ml (1.25 mg) i.v. 5 min before the end of surgery; transdermal placebo+ 0.5 ml placebo i.v. as indicated above. Oxycodone i.m. and glycopyrrolate i.v. were given for premedication together with the test adhesive. Anaesthesia was induced with thiopental and maintained with nitrous oxide and oxygen, enflurane, vecuronium and fentanyl. Neostigmine and glycopyrrolate were administered for reversal. In the recovery room no differences in nausea or vomiting were observed between the groups. Sedation was significantly more marked (P < 0.15–0.0001) after DHBP than after either TS or the placebo. An additional 1.25 mg DHBP was required in 28% of the patients given TS compared with 13% of those given DHBP and 6%, of those given the placebo (P <0.05). During the following 24 h nausea was reported more by the placebo patients (25) than by those on TS (20) or DHBP (15) (P <0.05). However, actual vomiting on the ward did not differ between the groups. Visual disturbances were more frequent after TS (P <0.01). We conclude that prophylactic transdermal scopolamine does not diminish postoperative emetic sequelae.
Pharmacokinetics of midazolam and alfentanil in outpatient general anesthesia: A study with concomitant thiopentone, flumazenil or placebo administration
Authors: Ræder J. C. , Nilsen O. G. , Hole A.
Published: January 2009

The pharmacokinetics of alfentanil, midazolam and thiopentone used for induction of short general anaesthesia were studied in 55 gynaecological outpatients. All the patients received midazolam as premedication. The patients received intravenous anaesthesia with alfentanil and either thiopentone or midazolam, supplemented with either nitrous oxide or air in oxygen ventilation, reversed by the end of anaesthesia with either placebo or flumazenil. Blood sampling for serum concentration measurements of midazolam, alfentanil and thiopentone was performed regularly for 7 h. The following mean pharmacokinetic parameters (mean ± –s.e.mean) were calculated for midazolam and alfentanil, respectively: elimination half–life 3.9 ± 0.3 h and 1.2 ± 0.05 h, apparent volume of distribution 107 ± 6 1 and 31 ± 1.5 1, total body clearance 20 ± 0.7 1/h and 18 ± 0.8 1/h. No influence of flumazenil on the kinetics of midazolam and no influence of thiopentone, midazolam, flumazenil or nitrous oxide on the kinetics of alfentanil was found. The serum levels of thiopentone were below the detection limit of the assay after 60 min, which made an evaluation of pharmacokinetic parameters impossible. Significant positive correlations were found in the individual patient between midazolam and alfentanil for all pharmacokinetic variables evaluated. For midazolam, an increase in the elimination half–life and the apparent volume of distribution was positively correlated to an increase of body–weight. For alfentanil, a decrease in the total body clearance and an increase in the elimination half–life were positively correlated to an increase of age. A prolonged elimination half–life of alfentanil was positively correlated to use of alcohol. High serum levels of thiopentone were positively correlated to increasing age of the patients.
Gaseous homeostasis during low‐flow anaesthesia
Authors: Bengtson J. P. , Sonander H. , Stenqvist O.
Published: January 2009

The object of this clinical study was to investigate the circle system gas homeostasis during low‐flow anaesthesia using a technique designed to keep a constant inspired oxygen fraction of 0.30. Denitrogenation was adequately accomplished with mask preoxygenation, 10 l/min, for 1 min and an initial fresh gas flow of 5 l/min for 6 min after intubation. There was no need to wash out accumulated nitrogen at intervals, since the already low nitrogen concentration in the system tended to decrease after 1 h. The fresh gas flow of nitrous oxide to oxygen ratio and the inspiratory to end‐expiratory oxygen concentration difference both reflected the uptake of nitrous oxide. The calculated rates of uptake of nitrous oxide, a subject of controversy, were in accordance with those found by Severinghaus and Barton & Nunn.
Pharmacokinetics and protein binding of bupivacaine in postoperative epidural analgesia
Authors: Wulf H. , Winckler K. , Maier Ch. , Heinzow B.
Published: January 2009

We describe a method, which is both specific and rapid, for the measurement of bupivacaine concentrations in plasma using high‐performance liquid chromatography. Bupivacaine plasma concentrations, pharmacokinetics and protein binding in the postoperative period were investigated in seven patients (58–77 years old) following hip surgery. Postoperative analgesia was achieved by epidural bolus injections of 25 mg bupivacaine 0.25% every 6 h. Sufficient pain relief without side‐effects was obtained. Total (maximum 1.13 μg/ml) as well as free (maximum 0.1 μg/ml) bupivacaine plasma concentrations remained below toxic threshold levels and no cumulation occurred. Increased protein binding in the postoperative period is reported, emphasizing the importance of measuring the free fraction in addition to the total plasma concentration. The free fraction decreased from 5.4% preoperatively to 2.7% in the postoperative period (P<0.05). Changes in plasma protein binding of bupivacaine and changes in plasma levels of the acute phase reactant α‐1‐acid glycoprotein were correlated (r = 0.8,P<0.05). Difficulties in interpreting the elimination parameters following epidural administration are discussed, leading to the conclusion that the derivation of dosage regimens from kinetic parameters following epidural administration is not warranted.
Influence of intraperitoneal anesthesia on pain and the sympathoadrenal response to abdominal surgery
Authors: Wallin G. , Cassuto J. , Högström S. , Hedner T.
Published: January 2009

The effects of intraperitoneal administration of bupivacaine on pain and the sympathoadrenal response to surgery were studied in a double‐blind randomized trial in 19 patients undergoing cholecystectomy. Bupivacaine (2 mg/kg) was dissolved in 300 ml isotonic saline and administered into the peritoneal cavity 10 min before the operation (n = 9). Saline was administered in a comparable group of patients (n = 10). There were no significant differences in pain scores between the groups during the first day after surgery (P>0.05). Postoperative requirements of pethidine during the first 2 days after surgery did not differ significantly between the groups. Blood glucose levels were significantly lower in the bupivacaine‐treated group 1 h (P<0.05) and 4 h (P<0.05) after skin incision. No significant differences were observed between the groups regarding plasma catecholamine and serum cortisol levels during and after surgery. Differences between the groups regarding urine output of catecholamines during the first and second postoperative days were not significant. Our results suggest that single administration of a local anesthetic intraperitoneally does not reduce pain or the sympathoadrenal response to upper abdominal surgery.
Primary evaluation of the local anaesthetic properties of the amino amide agent ropivacaine (LEA 103)
Authors: Åkerman B. , Hellberg I.‐B. , Trossvik C.
Published: January 2009

The local anaesthetic properties of l‐propyl‐2′,6′‐pipecoloxylidide, a congener of mepivacaine and bupivacaine, and its enantiomers were compared in animals. The (S)‐enantiomer (ropivacaine, LEA 103) produced a longer duration of sciatic nerve block and infiltration anaesthesia than the racemate and the (R)‐form. Ropivacaine and bupivacaine were equally potent in terms of block of evoked action potentialin vitroand minimum effective concentrationin vivo.Ropivacaine 0.25–1.0% was distinctly longer acting than bupivacaine on infiltration, equally effective in sciatic and brachial plexus block and somewhat shorter lasting in epidural and spinal blockade. There were tendencies towards a greater benefit from the addition of adrenaline with ropivacaine in epidural anaesthesia and a shorter latency to block in some of the tests. Ropivacaine seems less vasodilative than bupivacaine and capable of producing some vasoconstriction over a wider range of low concentrations, which may explain its longer duration of intradermal anaesthesia. The somewhat shorter duration of central blockade of ropivacaine is probably a result of lesser lipid solubility. Ropivacaine was less toxic (i.v. and s.c. LD50‐values) than bupivacaine but more toxic than lidocaine, and produced only weak local irritation. Due to a combination of interesting local anaesthetic properties and relative safety including cardiotoxic potential, we consider ropivacaine a candidate for further studies.
Intravenous infusion of midazolam, propofol and vecuronium in a patient with severe tetanus
Authors: Orko R. , Rosenberg P. H. , Himberg J.‐J.
Published: January 2009

An adult patient with severe tetanus was successfully treated with alternating long‐term infusions of propofol (20–80 mg/h, 8 + 3 days) and midazolam (5–15 mg/h, 29 days) for sedation, and with vecuronium infusion (6–8 mg/h, 35 days) for muscle relaxation. In addition, continuous infusion of labetalol (10–20 mg/h, 39 days) was given to control arterial blood pressure. Blood samples were taken daily for assays of propofol, midazolam and vecuronium plasma concentrations. No accumulation of propofol and vecuronium could be detected. There was an increase in liver enzyme activity at the end of the first 8‐day propofol infusion. During the 4‐week midazolam infusion, there were two marked plasma concentration peaks at times when the infusion rate was fairly stable. These changes coincided with pulmonary infection (C‐reactive protein elevated) and ciprofloxacin treatment. The patient awoke rapidly after the last propofol infusion. He was unable to recall anything about his stay in the intensive care unit.
Horner's syndrome after intrapleural anesthesia with bupivacaine for post‐herpetic neuralgia
Authors: Sihota M. K. , Holmblad B. R.
Published: January 2009

We observed the development of Horner's syndrome 25 min after the intrapleural administration of 30 cc of 0.5% bupivacaine to a patient with post‐herpetic neuralgia in the thoracic region. The patient reported immediate relief of pain. There was no change in blood pressure or pulse rate, and no discernible level of anesthesia to pinprick was detected.
Continuous‐flow apneic ventilation with small endobronchial catheters
Authors: Bunegin L. , Bell G. C. , Gelineau J. , Smith R. B.
Published: January 2009

This study compares gas exchange and hemodynamic parameters during bronchial insufflation with two different internal diameter (ID) catheters (2.5 and 1.4 mm) at a constant mean gas exit velocity. Anesthetized, paralyzed dogs were instrumented to monitor arterial, central venous, and airway pressures, blood gases, temperature, ECG, and ventilated using continuous flow apneic ventilation (CFAV) via 2.5‐mm or 1.4‐mm ID bronchial insufflation cathethers positioned 1.25 bronchial diameter units (BDU) beyond the carina. Initially, flow was adjusted to provide adequate oxygenation and ventilation through the 2.5‐mm ID catheters. After a 30‐min stabilization, physiological parameters were recorded and the mean gas exit velocity was calculated. The 2.5‐mm ID insufflation catheters were then replaced by 1.4‐mm ID catheters and the bronchial insufflation flow adjusted so as to produce the same mean gas exit velocity as for the 2.5‐mm ID catheters. After a 30‐min stabilization period, physiological parameters were again recorded. No significant differences were noted in arterial, central venous, or airway pressures, temperature, heart rate, pH, Paco2, and Pao2 between the 2.5‐mm and 1.4‐mm ID bronchial insufflation catheters. However, significantly less bronchial insufflation flow (69.7%) was required to maintain oxygenation and ventilation for the 1.4‐mm ID bronchial insufflation catheters.
QT interval of the ECG, heart rate and arterial pressure using five non‐depolarizing muscle relaxants for intubation
Authors: Saarnivaara L. , Klemola U.‐M. , Lindgren L.
Published: January 2009

The QT interval, heart rate and arterial pressure were measured during anaesthetic induction in 186 patients without cardiovascular diseases or any preoperative drugs. The study was randomized and double‐blind. The patients were premedicated with either pethidine 1 mg/kg + atropine 0.01 mg/kg or with only pethidine 1 mg/kg i.m. Anaesthesia was induced with thiopental. After both types of premedication, either d‐tubocurarine 0.5 mg/kg, alcuronium 0.3 mg/kg, pancuronium 0.1 mg/kg, vecuronium 0.1 mg/kg or atracurium 0.5 mg/kg was injected after thiopental. Laryngoscopy was performed 4 min after the relaxant. The control values of the QT intervals (mean value 433 ms, range of the mean values 422–453 ms), were comparable. After thiopental, the mean values in the groups were no longer in the normal range (<440 ms). After atropine, the values at 3 min were statistically significantly prolonged in the pancuronium, atracurium and alcuronium groups, but not in the other groups, when compared with the values after thiopental. In the absence of atropine, no statistically significant prolongation of the QT interval occurred. After intubation in the absence of atropine, the values were statistically significantly prolonged in the alcuronium, pancuronium, vecuronium and atracurium groups and in the presence of atropine in the atracurium group when compared with the preceding values. The QT intervals were prolonged only in relation to the increased heart rate. At 6.5 min, the values in all groups were decreased to about the same level as before intubation. The mean control values of the heart rate were between 80 and 90 b.p.m. in the atropine‐treated groups and between 70 and 80 b.p.m. in the other groups. Before laryngoscopy, neither heart rate nor arterial pressure changed significantly in any of the groups. In all groups, a cardiovascular intubation response occurred. The incidence of cardiac arrhythmias ranged from 19% to 22% in the atracurium, pancuronium and vecuronium groups and from 0% to 3% in the other groups. Atropine did not affect the incidence of arrhythmias.
Blood volume during transurethral prostatic resection
Authors: Hahn R. G.
Published: January 2009

The variations in blood volume (BV), occurring in the course of 61 transurethral prostatic resections and estimated by the haemoglobin dilution method, were examined in relation to the type and volume of i.v. fluid given, the amount of imgant absorbed and the blood loss. When dextran 40 was used (n=16), the BV increased within 10 min by 2.7 times the volume infused, while for cumulative data relating to several 10‐min periods in the course of surgery this factor was 1.3; for acetated Ringer solution (n=45), the respective values were 0.5 and 0.3–0.4. The half‐life of absorbed irrigating fluid in the circulation was between 5 and 10 min. In patients receiving dextran 40 the BV decreased by the volume of blood lost; however, when acetated Ringer solution was given, the BV decreased by only 60% of the blood loss.
Hepatic drug disposition in multiple organ failure
Authors: Schregel W. , Kuntz H.‐D. , Vitt M.
Published: January 2009

In 15 patients with multiple organ failure of septic etiology, some principal partial hepatic functions of drug disposition were measured by the test substances galactose, indocyanine green, theophylline and 4‐methylumbelliferon. Glucuronidation was not impaired in any case, whereas flow‐limited and capacity‐limited drug elimination can be influenced. Drug monitoring and intense clinical observation seem necessary to improve drug therapy and the outcome of patients with multiple organ failure.
Changes in ejection fraction during induction of anesthesia with two different i.v. techniques
Authors: Dahlgren G. , Brodin L.‐A. , öHqvist G. , Settergren G.
Published: January 2009

Two intravenous induction techniques were compared with respect to changes in ejection fraction (EF) and central hemodynamics in 30 patients scheduled for coronary artery surgery. Left ventricular EF was measured with a collimated single crystal probe linked to a microcomputer, after injection of 200 MBq Tc 99 m HSA. Stroke volume index (SI) determined by thermodilution and EF were used to calculate left ventricular volume in end‐systole and end‐diastole. In 20 patients (Group I), anesthesia was induced with diazepam (94 μg×kg‐1), thiopentone (3 mg·kg‐1) and fentanyl (3 μg×kg‐1). In 10 patients (Group II), fentanyl (30 μg×kg‐1) was used for induction. In Group I, EF decreased from 0.43 to 0.26 at intubation, while systemic vascular resistance index (SVRI) showed an increase. Left ventricular volume decreased during induction of anesthesia except during intubation. In Group II, EF and left ventricular volume remained unchanged during the study period. SVRI showed no increase at intubation. No change in contractility was indicated from the relation between the end‐systolic pressure and volume, in any of the groups.
Cardiac arrest during anaesthesia. A computeraided study in 250 543 anaesthetics
Authors: Olsson G. L. , Hallén B.
Published: January 2009

With the aid of a computer‐based anaesthetic record‐keeping system, all cardiac arrests during anaesthesia at the Karolinska Hospital between July 1967 and December 1984 were retrieved. There were a total of 170 cardiac arrests and 250543 anaesthetics in the data file, which gives an incidence of 6.8 cardiac arrests per 10000 anaesthetics. Sixty patients died, constituting a mortality of 2.4 per 10000 anaesthetics: 42 were considered as inevitable deaths (rupture of aortic or cerebral aneurysm, multitrauma, etc.); 13 cases of cardiac arrest were considered as non‐anaesthetic, i.e. complications due to surgery and other procedures. Nine of these patients died. 115 cases of cardiac arrest were considered as caused by the anaesthetic and nine of these patients died. Thus mortality caused by anaesthesia was 0.3 per 10000 anaesthetics. The most common cause of cardiac arrest due to anaesthesia was hypoxia because of ventilatory problems (27 patients), postsuccinylcholine asystole (23 patients) and post‐induction hypotension (14 patients). The highest mortality was seen when spinal or epidural anaesthetics were given to patients with impaired physical status including hypovolaemia. The incidence of cardiac arrest has declined considerably during the period studied, and this coincides with an increasing number of qualified anaesthetists employed in the department during the same period.
Local anaesthesia efficacy: discrepancies betweenin vitroandin vivostudies
Authors: Pateromichelakis S. , Prokopiou A. A.
Published: January 2009

Electrophysiological studies on isolated nerves have been used extensively in the past to assess the comparative efficiency of local anaesthetics as agents of peripheral nerve blockade. It is shown here that three closely related amide local anaesthetics behave differentlyin vitroandin vivo. In terms of onset of action and of maximum suppression of the evoked action potential, mepivacaine proved a less efficient anaesthetic than lidocaine or prilocaine on isolated nerves, but in parallel studies on the sciatic nerve of live animals and in the absence of vasoconstrictors: (a) mepivacaine's potency was superior to that of the other two agents, (b) its speed of onset of anaesthetic action was at least as good and (c) its duration of action was found to be considerably longer. These results, in combination with the physical properties of the anaesthetics examined, favour differential ionization as the cause of the reduced performance of mepivacaine in the nerve bath. Thus, studies on isolated nerves, which are often quoted in the pharmacological literature, can be poor guides to thein vivocomparative efficacy of local anaesthetics.
Prediction of severe postoperative complications in patients admitted to neuroanaesthesia
Authors: Pedersen T. , Jensen J. S. , Risbo A. , Henriksen E.
Published: January 2009

The purpose of this study was to identify factors which will predict the risk of severe postoperative complications in individual patients in a neurosurgical unit. Eleven risk factors were investigated in 363 neurosurgical patients, of whom 40 (11%) developed postoperative complications requiring mechanical ventilation for more than 24 h in an intensive care unit, 16 were found to be severely disabled or in a vegetative state at follow‐up 1 month after admission, and 28 patients died. By applying stepwise, logistic regression analysis to the patient's data, we were able to select two significant risk variables, i.e. the Glasgow Coma Scale (GCS) 8 or less preoperatively and emergency anaesthesia. The presence of GCS 8 or less on the consciousness scale was associated with postoperative complications in approximately 40% of the cases. Emergency patients with severe neurological damage had the greatest risk of postoperative complications (93%). Fatal outcome for patients with postoperative complications was seen in 40% of the cases.
Intraoperative heart rate reduction ‐ alinidine versus metoprolol
Authors: Gombotz H. , Metzler H. , Winkler G. , Rehak P.
Published: January 2009

In a double‐blind randomized protocol the effectiveness of the specific bradycardic agent alinidine (0.6 mg.kg‐1 i.v.) was compared to that of the betablocker metoprolol (0.035 mg.kg‐1 i.v.). Twenty‐four coronary artery disease patients undergoing a bypass procedure with an intraoperative heart rate increase of more than 20% were included. Patients with a concomitant intraoperative mean arterial pressure increase of more than 30% or with an intraoperative wedge pressure higher than 15 mmHg (2.0 kPa) were excluded. After application of alinidine and metoprolol, heart rate decreased significantly (P<0.01) in the alinidine group from 88 ± 19 beats per min to 72 ± 13 and in the metoprolol group from 82 ± 16 to 72 ± 12. Baseline values were not obtained. Compared to the hemodynamic changes in the metropolol group, the alterations of pulmonary capillary wedge pressure (P<0.05) (P<0.05), stroke volume index (SVI) (P<0.05), left ventricular stroke work index (LVSWI) (P<0.01) and right ventricular stroke work index (RVSWI) (P<0.05) in the alinidine group were statistically significantly different. PCWP remained unchanged after alinidine and increased in the metoprolol group (1.4 ± 0.4 to 1.6 ± 0.4 kPa). In the alinidine group LVSWI (43.1 ± 15 to 49.2 ± 18g‐m.m‐2), RVSWI (5.1 ± 4 to 6.6 ± 3 g‐m.m‐2) and SVI (37.2 ± 12.2 to 42.5 ± 12.8 ml.m‐2) increased. In the metoprolol group LVSWI (44.2 ± 8 to 40.6 ± 9 g‐m.m‐2) and RVSWI (5.5 ± 3 to 5.3 ± 2 g‐m.m‐2) decreased slightly, whereas SVI was unchanged. Based on the hemodynamic data alinidine seems to be a less cardiodepressive agent than metoprolol in phases of predominant sinus tachycardia. This drug may be especially advantageous for patients with suspected or documented ischemic heart disease, those who do not tolerate betablockers well and patients who require a greater heart rate reduction than can be obtained with betablockers.
Postoperative cerebrovascular accidents in general surgery
Authors: Larsen S. F. , Zaric D. , Boysen G.
Published: January 2009

In a prospective study of postoperative complications, strokes occurred in 6 out of 2463 patients (0.2%) who underwent non‐cardiac, non‐carotid artery surgery. The patients who experienced cerebrovascular accidents, including three cases of transient ischemic attack, were significantly older than the rest of the group (mean age 79 years versus 65 years) and had manifestations of atherosclerosis in at least one organ preoperatively. Significant predictors of risk for postoperative cerebrovascular accidents were previous cerebrovascular disease, heart disease, peripheral vascular disease, and hypertension. Cerebrovascular accidents occurred late in the postoperative period, 5–26 days after surgery, and were not directly related to surgery and anesthesia. They were more frequent after acute than after elective operations. Precipitating factors for some of the stroke incidents were rapid atrial fibrillation and postoperative dehydration.
Epidural clonidine for treatment of postoperative pain after thoracotomy. A double‐blind placebo‐controlled study
Authors: Jr T. Gordh
Published: January 2009

Clonidine has been reported to produce analgesia in humans in different painful conditions. The aim of the present study was to investigate if epidural clonidine produced a clinically important analgesia to severe postoperative pain. Using a controlled, randomized double‐blind design, one group of patients received a single dose of epidural clonidine 3 μg/kg (n = 10) and a control group epidural 0.9% saline (n= 10), when reporting postoperative pain after thoracotomy performed under standardized anaesthesia. To quantify the effects of the given epidural drugs, the need for supplementary, intravenous pethidine analgesia was recorded. The patients had access to the supplementary analgesic by means of a patient‐controlled analgesic‐delivery device. The two groups were similar regarding anthropometric and clinical data. Epidural clonidine 3 μg/kg did not affect the need for supplementary intravenous pethidine analgesia, as compared to the control group at any time during the first 12 h postoperatively. The side‐effects of epidural clonidine were tolerable, and no treatment for arterial hypotension was required. No early or delayed respiratory depression occurred. In conclusion, clonidine 3 μg/kg epidurally seems to lack clinically important analgesic effects on severe postoperative pain, at least following thoracotomy.
Intravenous or rectal administration of sedatives in outpatient oral surgery
Authors: Lundgren Stefan
Published: January 2009

A number of cross‐over studies on sedation in outpatient oral surgery investigated the quality of sedation produced by intravenous or rectal administration of diazepam. The sedation methods were equally efficient with a mean dose of 0.24 mg/kg (range 0.1–0.4) for i.v. administration and 0.53 mg/kg (range 0.5–0.6) for rectal administration. Eighty‐five percent of the patients preferred surgery under sedation and local anaesthesia to local anaesthesia alone. The patients preferred the session in which they experienced stronger sedation, regardless of the route of administration.
The use of oral sedatives in dental care
Authors: Hallonsten Anna‐Lena
Published: January 2009

Oral administration of tranquillizing and anxiety‐suppressing drugs has long been the commonest method of achieving light sedation. The benzodiazepines are the drugs of first choice. Benzodiazepines given orally may be indicated to avoid ‘treatment stress’, alleviate mild anxiety before dental treatment, and facilitate sleep on the night before the treatment. Furthermore, they could be used for the dental treatment of medically poor risk patients, particularly those with cardiovascular disease. The drug can be given either in a fractionated dose or a single dose. The recommended doses for diazepam vary from 0.1–0.8 mg/kg body weight, depending on age, with higher doses in children and lower doses in elderly patients. Few side effects are reported.
The use of sedatives in dental care: legal aspects in Sweden
Authors: Sundberg Hans
Published: January 2009

The patient's rights and the dentist's obligations within Swedish dental care are groverned by the Dental Care Act. The general dentist Instruction enjoins on every dentist, in accordance with science and tested experience, to advise and, as far as possible, to inform the patient about the treatment the patient's condition requires. Dentists have the right to prescribe sedative drugs. Intravenous injection of sedative agents may not at present be used by dentists. Dentists have the right to use nitrous oxide analgesia after undergoing training approved by the National Board of Health and Welfare. With regard to the nitrous oxide apparatus, it is stipulated that the concentration of oxygen must never fall below 40% volume. There are special directions for ventilation in the treatment room, portable exsuction, and other measures when nitrous oxide analgesia is used. It is specially directed how dentists shall keep case records in general. Stipulations also exist for the keeping of case records on nitrous oxide analgesia. Dentists are bound to report secondary effects of drugs to the National Board of Health and Welfare.
Transfusion transmitted human T‐lymphotropic virus infections
Authors: Grillner Lena
Published: January 2009

Human immunodeficiency virus (HIV) type 1 has emerged during the 1980s as an important transfusion transmitted agent. The impact of HIV depends on the epidemiology and characteristics of the virus, serological response to infection and efficacy of serological tests to identify infected blood units. These factors will be described in the present article. The risk to acquire HIV today, by transfusion of anti‐ HIV screened blood, is extremely small in Scandinavia and the Western world. The risk can be further minimized by more sensitive screening tests and an improved donor information. The epidemiology in Scandinavia of other members of the human T‐lymphotrophic viruses, HTLV‐1 and HIV‐2, has to be further investigated.
Hemodilution ‐ possibilities and safety aspects
Authors: Messmer Konrad
Published: January 2009

Normovolemic hemodilution is an essential part of the overall strategy to avoid exposure of patients to the hazards of homologous blood transfusions. It includes beneficial effects on the flow properties and flow conditions of blood. A hematocrit of 30% can be regarded as an optimal compromise between the fluidity and the oxygen content of the blood. Compensatory responses such as increased cardiac output and stroke volume occur following hemodilution. In patients with compromised coronary reserve the degree of hemodilution that is tolerated has to be carefully considered. Therefore specific selection criteria for patients to be preoperatively hemodiluted are needed. For reasons of safety, efficiency and practicability colloid solutions rather than crystalloid solutions should be used for intentional hemodilution.
Peroperative blood salvage
Authors: Solem Jan Otto , Vagianos Constantin
Published: January 2009

The procedure of autotransfusion includes the collection of the patient's own blood before, during or after surgery with the aim of retransfusing it either immediately or postoperatively. The increasing demands on the blood banks as well as the growing fear of transfusion transmitted diseases have created a new interest in autotransfusion. Application of autotransfusion will reduce the need for homologous blood and thereby cut the cost.
New transfusion practice and haemostasis
Authors: Myllyä Gunnar
Published: January 2009

Haemostatic deficiency following blood transfusion and surgery is caused by multifactorial mechanisms. Various protocols of component therapy have been used to prevent the haemostatic abnormalities and bleeding tendency. In planning the protocols, the defect is considered to be mainly due to dilution. Prophylactic use of fresh frozen plasma and/or platelet concentrates have not proved to be very effective. Treatment of the bleeding tendency should therefore be based on specific diagnosis of the haemostatic defect.
Chest wall rigidity during fentanyl– and midazolam–fentanyl induction: ventilatory and haemodynamic effects
Authors: NEIDHART P. , BURGENER M. C. , SCHWIEGER I. , SUTER P. M.
Published: January 2009

In a double–blind randomised study, we examined if pretreatment with small doses of midazolam, given before anaesthesia induction with fentanyl, influences the occurrence of fentanyl–induced thoracic rigidity (FITR). At the same time, the effect of rigidity on the cardiovascular and respiratory system was assessed. Sixteen patients undergoing coronary artery bypass surgery were divided into two groups. The midazolam group (M) received 0.075 mg/kg midazolam i.v. and the placebo group (P) NaCl 0.9% 3 min before the start of fentanyl induction. During the induction period, FITR was assessed clinically on a 3–point scale. Haemodynamic and respiratory variables were collected before anaesthesia induction, at the end of the fentanyl infusion and 3 min after intubation. The incidence of FITR was high in both groups: 63% in Group M and 75% in Group P (n.s.); however, its severity was less in Group M. The appearance of rigidity affected the cardiovascular and the respiratory system: central venous and pulmonary capillary wedge pressures showed a sharp increase in patients with FITR accompanied by CO2 retention, due to an inability to ventilate these patients adequately. We conclude that small doses of midazolam do not prevent, but may attenuate, FITR and that the appearance of rigidity causes alterations of haemodynamic and respiratory variables during induction.
Cerebral blood flow and metabolism during adenosine–induced hypotension in patients undergoing cerebral aneurysm surgery
Authors: LAGERKRANSER M. , BERGSTRAND G. , GORDON E. , IRESTEDT L. , LINDQUIST C. , STANGE K. , SOLLEVI A.
Published: January 2009

The effects of adenosine–induced hypotension on cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRo2), and cerebral lactate production, together with systemic haemodynamics, were studied in 10 patients undergoing cerebral aneurysm surgery in neurolept anaesthesia with controlled hyperventilation. CBF changes were determined in six of the patients with a retrograde thermodilution technique in the jugular vein. Hypotension was induced with a continuous infusion of adenosine in the superior vena cava. The dose range was 0.06–0.35 mg/kg/min, and this caused a 42% reduction in mean arterial blood pressure (MABP) from 79 × 4 to 46 × 1 raraHg (10.5 × 0.5 to 6.1 × 0.1 kPa) through a profound reduction in systemic vascular resistance (SVR), which amounted to 61%. No significant change occurred in CBF. Whole body AV–difference of oxygen was decreased by 37%, and cerebral AV–difference by 28%, corresponding to reductions in whole body oxygen uptake and CMR02 of 16 and 17%, respectively. Cerebral AV–difference of lactate did not change. In the posthypotensive period MABP was increased by 10%, together with a minor increase in CBF (15%). It is concluded, that adenosine–induced hypotension at MABP levels between 40–50 mmHg (5.3–6.7 kPa) does not affect cerebral oxygenation unfavourably, and may even offer a protective effect by reducing cerebral oxygen demand. The slight CBF increase in the posthypotensive period was probably secondary to an increase in MABP together with a blunted autoregulation, but in no case was this effect considered to be harmful for the patient.
Flumazenil used for antagonizing the central effects of midazolam and diazepam in outpatients
Authors: JENSEN S. , KNUDSEN L. , KIRKEGAARD L. , KRUSE A. , KNUDSEN E. B.
Published: January 2009

In a double–blind, randomized trial, the efficacy and safety of flumazenil, a benzodiazepine antagonist, was evaluated in patients after gastroscopy under midazolam or diazepam sedation. The criteria of efficacy were the degree of sedation and anterograde amnesia. Flumazenil significantly reduced the degree of sedation in both groups without significant intergroup differences. No sign of resedation was found during the observation period of 3 h. The anterograde amnesia was effectively antagonized in both groups. Flumazenil was well tolerated. Flumazenil is a safe and effective benzodiazepine antagonist which makes it possible to reduce the recovery period in outpatients sedated sufficiently with benzodiazepines for gastroscopy.
Right ventricular dysfunction in septic shock: assessment by measurements of right ventricular ejection fraction using the thermodilution technique
Authors: VINCENT J. L. , REUSE C. , FRANK N. , CONTEMPRÉ B. , KAHN R. J.
Published: January 2009

Right ventricular ejection fraction (RVEF) was measured by the thermodilution technique in a scries of 127 consecutive critically ill patients monitored with a modified pulmonary artery (PA) catheter equipped with a fast response thermistor. Thermodilution RVEF was significantly lower in septic shock (23.8 8.2%, 93 measurements) than in sepsis without shock (30.3 10.1%, 118 measurements) or in the absence of sepsis or cardiopulmonary impairment (32.5 7.1%, 62 measurements). Both myocardial depression and pulmonary hypertension could account for this impairment of RV function. RVEF decreased from 35.1 9.8 to 24.2 10.4% (P < 0.01) during development of septic shock and increased from 25.0 7.6 to 29.8 8.5%, (P < 0.05) during recovery (14 patients). Initial RVEF in septic shock was 27.8 8.6% in 11 patients who survived but only 20.9 6.7% (P < 0.02) in the 23 patients who eventually died. Thus, RV dysfunction is common during septic shock, is directly related to its severity, and can easily be recognized in patients monitored with a PA catheter.
Atracurium and pancuronium in renal insufficiency
Authors: BERNTMAN L. , ROSBERG B. , SHWEIKH I. , YOUSEF H.
Published: January 2009

The duration and possible accumulation of atracurium and pancuronium were studied in 59 patients (29 anephric and 30 normal) anaesthetized with 0.5% halothane in O2/N2O and supplemented by fentanyl. Equipotent doses of atracurium (0.5 mg–kg‐1) and pancuronium (0.1 mg–kg‐1) were given for intubation. Atracurium had a lower potency in anephric patients. The duration (first twitch response (TI) return to 20% of control) for atracurium was 28 min in anephric and 36 in normal patients. The corresponding mean times for pancuronium were 171 and 123 min, but with a very wide variation (range 20–380 min and 45–360 min, respectively). The duration of up to 8 incremental doses of atracurium (0.1 mg kg‐1) was 27 29 min in normal patients and of up to 13 increments was 25–34 min in anephric patients. Pancuronium (0.015 mg kg‐1) was given in a maximum of 4 increments. In normal patients the mean durations were 40–56 min, and in anephric patients 65–100 min. The duration of pancuronium, but not of atracurium, was prolonged with repeated injections (up to 2.7 times) in anephric patients. After pancuronium the spontaneous recovery was significantly slower in anephric patients, while the induced recovery was rapid and reliable in all groups. We conclude that atracurium is a safe and reliable muscle relaxant in normal and anephric patients, while pancuronium in both groups has a disturbing variation in duration and, in addition, signs of significant accumulation in anephric patients. The use of a nerve stimulator is mandatory.