bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of swine susceptible to malignant hyperthermia by in vivo, in vitro and post‐mortem techniques
Authors: Seewald M. J. , Eichinger H. M. , Lehmann‐Horn F. , Iaizzo P. A.
Published: January 2009

We investigated German Landrace pigs from a special breeding program producing animals which were of three genotypes with respect to in vivo halothane inhalation (i.e., exposure to 3% halothane for up to 3 min): (1) Hal NN, i.e. homozygous normal exhibiting no response; (2) Hal Nn, i.e. heterozygous, also responding with a normal reaction; and (3) Hal nn, i.e. homozygous for the ‘halothane gene n’ which exhibited signs of malignant hyperthemia (MH). Additional characteristics of these three groups of animals were studied using accepted methodology from the fields of animal science, clinical testing, and food science. The following characteristics of group (2) and (3) were different from those of the normal animals: 1) creatine kinase levels; 2) in vitro sensitivities of muscles to caffeine and halothane administration (contracture test) and 3) postmortem muscle properties. In humans, results of the in vitro contracture test are indicative of susceptibility to MH. In humans, MH is considered to be inherited as an autosomal dominant trait. Similarly the results of the in vitro contracture test described here also indicate that MH is inherited as an autosomal dominant trait in German Landrace swine.
Haemodynamic responses and prolongation of QT interval of ECG after suxamethonium‐facilitated intubation during anaesthetic induction in children: a dose‐related attenuation by alfentanil
Authors: Lindgren L. , Rautiainen P. , Klemola U.‐M. , Saarnivaara L.
Published: January 2009

The haemodynamic response to endotracheal intubation and changes in the QT interval of ECG during anaesthetic induction were studied in 68 healthy children (5.5 years). The children were pretreated double‐blindly with either alfentanil 10 μg/kg (A10), 25 μg/kg (A25), 50 μg/kg (A50) or saline (control) (17 children in each group) i.v. 1 min before thiopentone 5 mg/kg. The trachea was intubated after suxamethonium 1.5 mg/kg. Central nervous system excitation was seen in four of 17 and in one of 17 children after alfentanil 50 and 25 μg/kg, respectively. After intubation, heart rate increased significantly in the control group, remained at initial levels in the A10 and A25 groups and decreased in the A50 group. A pressor response to intubation was seen in the control and A10 groups. The QT interval was significantly prolonged after suxamethonium in the control and A10 groups, but remained at baseline levels in the A25 and A50 groups. Ventricular ectopic beats were only seen in 2/17 children in the control group. In conclusion, alfentanil 25 μg/kg is ideal for preventing the haemodynamic response to endotracheal intubation and prolongation of the QT interval, a sign of sympathoadrenal activation, before induction of intravenous anaesthesia in children.
Effects of thiopental and halothane on spontaneous contractile activity induced in isolated ventricular muscles of the rabbit
Authors: Komai H. , Redon D. , Rusy B. F.
Published: January 2009

To see if the known properties of thiopental of reducing Ca2+and K+ fluxes across the myocardial sarcolemma account for its arrhythmogenic action, we have evaluated the effect of the anesthetic on spontaneous contractile activity induced in isolated rabbit papillary muscles. Thiopental (20 mg/1) prolonged the duration of sustained automaticity induced by stimulation at 1–2 Hz in the presence of 1 μmol/I isoproterenol. Thiopental (10, 20 mg/l) shortened the delay before the onset of Ba2+‐induced automaticity, which involves a decrease in a K+ current. The minimum concentration of Ba2+required to induce automaticity was lowered by thiopental. Whether spontaneous activities were induced by high frequency stimulation in the presence of isoproterenol or by Ba2+, thiopental lowered the frequency of spontaneous beats. Thus, thiopental appears to have both arrhythmogenic and antiarrhythmic actions, and the former may be unmasked when catecholamines counteract the latter by increasing Ca2+influx. Like thiopental, halothane (1.0%) decreased the frequency and force of Ba2+‐induced automatic beats but, unlike thiopental,prolongedthe delay before the onset of Ba2+‐induced automaticity, indicating that halothane acts as a purely antiarrhythmic agent in this type of automaticity.
Malignant hyperthermia: an altered phospholipid and fatty acid composition in muscle membranes
Authors: Seewald M. J. , Eichinger H. M. , Iaizzo P. A.
Published: January 2009

There is thought to be a genetic defect within the calcium release channel of the sarcoplasmic reticulum in malignant hyperthermia (MH). This primary alteration is hypothesized to influence the function and/or structure of various muscle membrane systems; e.g., to have a direct effect on the composition of the lipid matrix. Therefore, in striated muscle samples, we determined the quantity and fatty acid composition of the various types of membrane phospholipids. German Landrace pigs were classified as normal or susceptible to MH. Total lipid content from longissimus dorsi, semi‐membranosus muscle, and heart left ventricular (HLV) samples were extracted with chloroform/methanol and subsequently separated by high performance liquid chromatograpy. The single phospholipid fractions were collected and, following derivatization, the quantities of individual fatty acids were determined using a capillary gas chromatographic method. In general, samples from the susceptible pigs contained lower absolute amounts of individual phospholipids. The most notable differences occurred in the HLV, where phosphatidylinositol, phosphatidylserine, phosphati‐dylethanolamine and sphingomyelin were all significantly less (P ≤0.05). The muscle from the susceptible animals also contained decreased amounts of the polyunsaturated phospholipid‐bound fatty acids (P ≤0.05). These differences in phospholipid and fatty acid concentrations of membranes isolated from swine susceptible to MH may relate to their apparently increased sensitivities to halothane (e.g., fluidizing effects) or elevated temperature.
The effect of peripheral hypothermia on a vecuronium‐induced neuromuscular block
Authors: Eriksson L. I. , Viby‐Mogensen J. , Lennmarken C.
Published: January 2009

Seven healthy patients were investigated during midazolam‐fentanyl nitrous oxide‐oxygen anaesthesia. The mechanical twitch response of the adductor pollicis muscle was recorded simultaneously during bilateral supramaximal train‐of‐four (TOF) stimulation of the ulnar nerves at the wrist. Intense neuromuscular block was evaluated using the post‐tetanic count (PTC) method. Core temperature and the peripheral skin temperature of one arm were kept normal and stable. Following cooling of the other arm to a peripheral hand skin temperature of 27d̀C, vecuronium was administered in a bolus dose of 0.05 mg‐kg‐1 followed by maintenance doses of 0.02 mg‐kg‐1. In the hypothermic and the normothermic arm the onset time following the bolus dose was 180 ± 40 (mean ± s.d.) seconds and 140 ± 30 s, respectively, the duration of action was 26.4 ± 4.5 and 16.5 ± 4.0 min and the recovery time was 265 ± 90 and 130±60 s (P<0.01). The time course of action following maintenance doses showed a similar marked difference between the hypothermic and the normothermic arm. In the normothermic arm a close correlation was found between the number of posttetanic twitches and the time to first response to TOF stimulation. In contrast, in the hypothermic arm the number of post‐tetanic twitches showed great variation with a poor correlation to the duration of intense neuromuscular block. It is concluded that the time course of action of a vecuronium‐induced neuromuscular block is markedly prolonged during peripheral hypothermia and intense neuromuscular block cannot reliably be assessed using the PTC method at low peripheral temperature. Normal core and peripheral temperature is essential for correct evaluation of a neuromuscular block.
Expired‐breath ethanol measurement in chronic obstructive pulmonary disease: implications for transurethral surgery
Authors: Hahn R. G. , Jones A. W. , Billing B. , Stalberg H. P.
Published: January 2009

If ethanol is added to the irrigant used during transurethral prostatic resection, the absorption of fluid can immediately be detected by measuring the ethanol concentration in the expired breath. To evaluate this method further, we studied the influence of chronic obstructive pulmonary disease (COPD) on the agreement between expired‐breath and blood‐ethanol concentrations. In 14 men with a mean age of 62 years (range 55–68), the concentrations of ethanol in whole blood and end‐expired breath were measured at 12 exactly timed intervals before, during, and after an intravenous infusion of 0.6 g‐kg‐1 ethanol for 60 min. The pulmonary function was normal in seven of the subjects (control group) whereas the other seven suffered from severe COPD (study group). The results show that the accuracy and precision of breath‐alcohol analysis to predict the blood‐ethanol level were poorer during the infusion of ethanol than afterwards. However, at all times of sampling the estimation of blood‐ethanol concentration indirectly by analysis of breath was not significantly different for COPD patients and the control group. We conclude that ethanol monitoring of irrigant absorption can be used successfully in patients with COPD.
Variations in superficial renal cortical blood flow and tissue oxygenation: an experimental porcine model
Authors: Sandin R. , Wahlberg J. , Modig J.
Published: January 2009

Renal cortical microcirculation and its relation to inulin clearance, central haemodynamics and pulmonary gas exchange were studied in eight pigs under continuous intravenous chlormethiazole‐pancuronium anaesthesia. The animals were studied during six consecutive 30‐min periods. Four of the animals were also studied 19 h after the first period. In the superficial renal cortex, regional blood flow (Q) was measured by laser Doppler flowmetry (LDF) and tissue oxygenation (P1o2) by surface microelectrode technique. Central haemodynamics and pulmonary gas exchange values were distributed within normal ranges. The importance of stable central haemodynamics in order to perform accurate microcirculatory measurements in the renal cortex was documented. A significant relation between Q and pulmonary capillary wedge pressure (PCWP) was found (P <0.0001) despite the fact that PCWP was distributed within a range of only 0.7 kPa (all values were well within the normal range for pigs). No other relationships were found between central haemodynamics or pulmonary gas exchange variables and renal microcirculatory parameters. Concerning renal microcirculation and inulin clearance, at least 2–3 h may be required for stabilization after surgery. The average temporal variability between measurements performed every 30 min in each animal was 6 ± 7% (s.d.) in the LDF values and 21 ± 21% in the P1o2, values (mean P1o2,). No correlations were found between Q or P1o2, and inulin clearance. Since the haemodynamic parameters, pulmonary gas exchange variables and haematocrit were distributed within narrow ranges, we regard the temporal microcirculatory variability obtained here as normal in this experimental situation, and consider the porcine model well suited for further studies concerning renal microcirculation.
Model‐based adaptive closed‐loop feedback control of atracurium‐induced neuromuscular blockade
Authors: Olkkola K. T. , Schwilden H. , Apffelstaedt C.
Published: January 2009

Closed‐loop control of atracurium‐induced neuromuscular blockade by a model‐based adaptive feedback algorithm is described. Mean offsets (± s.d.) from setpoints at 50, 70 and 90% neuromuscular blocks using the Relaxograph® were 1.1 ± 1.3, 0.2 ± 0.7 and 0.1 ± 0.4%, respectively. Correspondingly, the mean steady‐state rates of infusion of atracurium were 0.20 ± 0.06, 0.25 ± 0.03 and 0.39 ± 0.10 mg ‐ kg‐1 ‐ h‐1. The described controller provides reasonable control of atracurium dosing at different degrees of neuromuscular blockade. It gives a solution to the problem of adapting pharmacokinetic and pharmacodynamic data to individuals when using population mean data as starting values for drug therapy.
Effects of glycopyrrolate and atropine on heart rate variability
Authors: Ali‐MelkkilÄaA T. , Kaila T. , Antila K. , Halkola L. , Iisalo E.
Published: January 2009

Analysis of heart rate variability, combined with physiological tests (deep breathing and tilt tests) was used to characterise the effects of atropine and glycopyrrolate on the parasympathetic nervous tone of the heart in healthy male volunteers. The low dose of atropine (120 μg) administered as a continuous infusion in 15 min was associated with parasympatomimetic effects estimated by the slowing of the heart rate and an increase of the mean and beat‐to‐beat heart rate variability. The bradycardia and increase of heart rate variability following infusion of glycopyrrolate (50 μg) was less marked and did not differ significantly from that of placebo. The higher doses of atropine (720 μg) and glycopyrrolate (300 μg) administered as a continuous infusion in 15 min produced an equal vagal cardiac blockade characterised by significant tachycardia and a decrease in overall and beat‐to‐beat heart rate variability. It is concluded that at low doses the parasympatomimetic action of glycopyrrolate is less marked than that of atropine; and at higher doses only small differences exist between these two muscarinic antagonists in their effects on cardiac vagal outflow, assessed by heart rate and heart rate variability.
Postischaemic renal cortical microcirculation and tissue oxygenation in the pig
Authors: Sandin R. , Wahlberg J. , Modig J.
Published: January 2009

Porcine and human renal physiology are similar in important aspects. Renal cortical microcirculation and its relation to inulin clearance (CIn) was therefore studied before and after renal ischaemia in 28 pigs under continuous intravenous chlormethiazole‐pancuronium anaesthesia. The anaesthesia used provided essential stability in central haemodynamics. The animals were studied for 90 min of reperfusion following 0, 30 or 60 min of renal ischaemia. Twelve of the animals (four were subjected to each duration of ischemia) were also studied 18 h after start of reperfusion. Regional blood flow in the superficial renal cortex was measured by laser Doppler flowmetry (LDF), and tissue oxygenation (Pto2) by surface microelectrode technique. These techniques allow continuous or repeated measurements. During the first 90 min of reperfusion, superficial renal cortical blood flow measured by LDF (Qsrc) underwent considerable temporal variation which followed a certain pattern. Thus, when the renal arterial blood flow was restored after ischaemia, we observed an instant peak in Qsrc followed by a decreasing flow until a minimum value (Qmin) was reached between 3 and 9 min after start of reperfusion (tQmin). Thereafter, Qsrc increased until a maximal value (Qmax) was reached between 11 and 64 min after start of reperfusion (tQmin). The parameters tQmin and tQmax were related to inulin clearance 18 h after start of reperfusion (P<0.05 and P<0.01, respectively). Thus, it might be possible soon after start of reperfusion – to evaluate the severity of ischaemic damage. This could be useful in the evaluation of different prophylactic strategies, since the full extent of the ischaemic damage, as assessed by clearance determinations, cannot be established until hours later. In both groups the renal cortical tissue oxygenation 15 min after start of reperfusion was fairly similar to that before ischaemia. However, re‐oxygenation of the superficial renal cortex was more rapid after 30 min of ischaemia compared with that after 60 min. Regional lack of oxygen due to increased microcirculatory heterogeneity despite adequate regional blood flow measured by LDF was also ruled out. The impairment in inulin clearance during the first 90 min postischaemia was not related to reduced oxygen availability in the superficial renal cortex.
Individual predictability of repeated spinal anaesthesia with plain 0.5% bupivacaine
Authors: Sloth E. , Kristoffersen E. , Husted J. C. , Bach A. B. , Zülow I.
Published: January 2009

To evaluate the individual predictability of spinal anaesthesia, 10 patients (3 women and 7 men) scheduled for control cystoscopy were studied twice within 9 months. Lumbar puncture was performed in the midline at the L2/3 interspace with the patient in the sitting position using plain 0.5% bupivacaine at 37d̀C. A non‐parametric Spearman test showed that, on the basis of the first block, the predictability of the cephalad analgesic spread of the second anaesthesia was high up to 60 min after injection. Thereafter the predictability decreased. The predictability of the motor blockade was generally low. Six patients obtained complete motor blockade twice; the remaining four, once.
Plasma renin, catecholamines, vasopressin and aldosterone during hypotension induced by labetalol with isoflurane
Authors: Toivonen J.
Published: January 2009

Deliberate hypotension may induce secretion of stress hormones. In the present study, the effects of hypotension induced by labetalol with isoflurane on plasma renin activity, plasma concentrations of adrenaline, noradrenaline, vasopressin, and aldosterone were investigated in eight adult patients undergoing middle‐ear surgery. The mean arterial pressure was 50 mmHg (6.7 kPa) during hypotension. Plasma renin activity rose significantly during anaesthesia before hypotension, being similar during hypotension and before hypotension, and it returned postoperatively to the initial level. Plasma adrenaline fell significantly during hypotension and rose after anaesthesia to the preanaesthetic level. Plasma noradrenaline rose slightly during hypotension and after anaesthesia, but not significantly. Plasma vasopressin rose significantly after anaesthesia. Plasma aldosterone increased slightly throughout the study, but not significantly during any phase. In conclusion, labetalol with isoflurane‐induced hypotension seems to attenuate the stress response in these operations. During hypotension, plasma renin activity is not an essential compensatory mechanism, which antagonises the decrease of blood pressure. Plasma vasopressin has no role in regulating blood pressure during labetalol‐induced hypotension.
Pretreatment with pancuronium before suxamethonium administration in patients heterozygous for the usual and the atypical plasma cholinesterase gene
Authors: Østergaard D. , Viby‐Mogensen J. , Hanel H. K. , Skovgaard L. Theil
Published: January 2009

The object of this study was to investigate whether pretreatment with pancuronium before i.v. injection of suxamethonium could cause prolonged neuromuscular blockade in patients heterozygous for the usual and the atypical plasma cholinesterase gene (E*1E*1). Forty‐three patients, 23 with genotype E*1E*1* and 20 with normal genotype (E*1E*1), were pretreated with pancuronium 0.01 mg‐kg‐1followed by suxamethonium 1.5 mg‐kg‐1, and received either neurolept anaesthesia or halothane anaesthesia. Seven patients (E*1E*1) were given suxamethonium 1.5 mg‐kg‐1without pretreatment. The duration and type of neuromuscular block were evaluated using train‐of‐four (TOF) nerve stimulation. Type of anaesthesia did not significantly influence the results. The duration of block following pretreatment was significantly longer in heterozygous patients than in normal patients. Time to 90% twitch height recovery was 10.7 ± 1.2 min (mean ± s.d.) in genotypically normal patients, and 18.0 ± 4.2 min in patients with genotype E*1E*1. Pretreatment with pancuronium caused a significantly slower recovery of the TOF ratio (phase II block). Thus, a TOF ratio of 0.7 was always reached within 13 min in genotypically normal patients. In genotypically abnormal patients, the same TOF ratio was reached within 20 min in all but three patients. In these three patients time to 90% twitch height recovery was prolonged (18–31 min), and TOF ratio did not return to normal, but stabilized at about 0.35, 0.50, and 0.65, respectively. Injection of edrophonium restored normal neuromuscular function in 10 min. It is concluded that in patients heterozygous for the usual and the atypical gene, pretreatment with pancuronium in combination with an increased dose of suxamethonium may cause a phase II block and thus a prolonged neuromuscular block.
The efficacy of intravenous indomethacin in prevention of postoperative pain
Authors: Tigerstedt I. , Tammisto T. , Neuvonen P. J.
Published: January 2009

Since intravenous prophylactic anti‐inflammatory agents have been suggested to reduce or even replace opiates in postoperative pain therapy, we studied the demand for morphine in 45 patients recovering from abdominal surgery who had received a baseline infusion of either indomethacin, morphine or saline placebo. When extubated after inhalational anaesthesia, each patient received an i.v. bolus of either 0.5 mg · kg‐1indomethacin, 0.07 mg · kg‐1morphine or saline placebo. Thereafter a 20‐h infusion of the same test analgesic was started, either 0.1 mg · kg‐1· h‐1indomethacin, 0.03 mg · kg‐1· h‐1morphine or saline placebo. For additional analgesia, a patient‐controlled analgesia device (PCA) delivering 5‐mg boluses of morphine was used. For the first 5 postoperative hours, significantly more (P<0.05) PCA morphine was needed in the indomethacin group (35 mg) than in the morphine group (24 mg), while the placebo group demanded mean 30 mg. For equal analgesia (measured by VAS and VRS) between 5–20 h, similar amounts (mean 23 and 19 mg) of PCA morphine were required in the indomethacin and morphine groups, in contrast to the placebo group (mean 40 mg) (P<0.001). Morphine infusion increased the total consumption of morphine by 25% as compared to placebo. We conclude that, following abdominal surgery, the analgesic effect of indomethacin infusion became apparent after the first 5 postoperative hours, thereafter reducing the demand for PCA morphine by about 40%. Continuous morphine infusion diminishes the postoperative demand for PCA morphine, but also increases the total morphine consumption.
The caffeine contracture test for malignant hyperthermia: caffeine citrate, caffeine benzoate or caffeine free base?
Authors: Heytens L. , Heffron J. J. A. , Camu F.
Published: January 2009

The aim of the present study was to investigate whether the three different caffeine preparations — caffeine citrate, caffeine benzoate and the free base — used forin vitrodiagnosis of malignant hyperthermia susceptibility — produced the same amount of contracture in rat diaphragm. At equimolar caffeine concentrations, the pure base generated more tension in the rat diaphragm muscle than caffeine benzoate or caffeine citrate. The citrate lowers the pH and the free Ca2+concentration of the test bath and thus suppresses the caffeine contracture. The benzoate is believed to inhibit the caffeine contracture by its carbonyl group in a way similar to the effect of benzocaine.
Changes in body heat during hip fracture surgery: a comparison of spinal analgesia and general anaesthesia
Authors: Bredahl C. , Hindsholm K. B. , Frandsen P. C.
Published: January 2009

Postoperative hypothermia initiates an increased oxygen demand in the postoperative period and may endanger patients with restricted cardiopulmonary reserves. In order to compare net heat losses and gains, we studied 28 women undergoing hip fracture surgery, using either general anaesthesia or spinal analgesia. The superficial and central temperatures were followed in the per‐ and postoperative period. Total body heat was calculated from temperature measurements. Temperature changes were unrelated to the type of anaesthesia. Large net heat losses occurred on transfer to the recovery room.
Thoracic impedance as an index of body fluid balance during cardiac surgery
Authors: Perko G. , Perko M. J. , Jansen E. , Secher N. H.
Published: January 2009

Thoracic impedance at 2.5 (TI2.5) and 100 kHz (TI100), central venous pressure [CVP], and body fluid balance were recorded together with rectal temperature and arterial haematocrit in 15 consecutive patients subjected to coronary artery bypass grafting. I.v. fluid and blood were administered in an excess of 3.18 (1.38–9.35) I during the operation. TI2.5 decreased from 51.7 (39.2–66.4) to 34.9 (21.1–45.7) ohm (P = 0.001), white TI100 decreased from 41.9 (31.4–55.0) to 30.3 (18.3–40.8) ohm (P = 0.002). CVP, 6 (3–11) mmHg [0.8 (0.4–1.5) kPa], was the same before and after surgery. Temperature decreased during cardiopulmonary bypass from 35.4 (34.1–36.6) to 26.7 (22.9–31.0)d̀ C and haematocrit from 39 (34–46)% to a lowest value of 27 (23–32)% (P = 0.0001). A close linear correlation between Tt and body fluid balance was observed (Tl25.r = ‐0.96, TI100:r= ‐0.95, P = 0.0001). Corrections ofTI for temperature and/or haematocrit improved the correlation between TI and fluid balance to 0.99 (TI25) and 0.98 (TI2.5). The data indicate that changes in thoracic impedance can be used to monitor body fluid balance during cardiac surgery.
The addition of sodium bicarbonate to prilocaine solution during i.v. regional anesthesia
Authors: Solak M. , AktÜuUrk G. , Erciyes N. , ÖOUzen I. , CLolak M. , Duman E.
Published: January 2009

A comparison of plain prilocaine and bicarbonated prilocaine in intravenous regional anesthesia was studied in 30 patients undergoing upper extremity surgery. The patients were divided into two groups: one group was given anesthesia in the form of 1% prilocaine and the other group was given 1% prilocaine plus sodium bicarbonate. The onset of analgesia and anesthesia and recovery from analgesia and anesthesia were investigated in both groups. Bicarbonated prilocaine produced faster onset of analgesia when compared with plain prilocaine (P<0.01). The onset of anesthesia and recovery from analgesia and anesthesia were not statistically different between the two groups. Clinically, the intensity of anesthesia was better when bicarbonated prilocaine solution was used instead of plain prilocaine. We conclude that bicarbonated prilocaine is better than plain prilocaine during IVRA.
Anaesthesia for cardioversion — clinical experiences with propofol and thiopentone
Authors: Sternlo J.‐E. , Hägerdal M.
Published: January 2009

A 1‐year population of anaesthesias for cardioversion of supraventricular tachyarrhythmias was studied. Propofol and thiopentone were used alternately for every other procedure, and the anaesthetic‐ and monitoring procedures were prospectively standardized. Twenty‐one thiopentone‐ and 23 propofol‐anaesthetized patients, who had been subjected to elective cardioversions of atrial fibrillation were compared, particularly regarding possible differences in the energy requirements for cardioversion and in the time intervals to initial awakening. There were no significant differences between the two drugs in the maximum systolic blood pressure drop, in the total mean energy requirements per kg bodyweight, or in the distribution of the number of patients over the various energy levels needed for restoration of sinus rhythm. Somewhat unexpectedly, however, the mean time interval to initial awakening was significantly longer in the propofol‐anaesthetized group. Apart from this minor drawback, propofol proved to be as useful an anaesthetic agent as thiopentone for the cardioversion procedure, and may be considered as an alternative drug in selected cases.
A comparative study of five different techniques to reduce left ventricular dysfunction during endotracheal intubation
Authors: Dahlgren G. , Settergren G. , Öhqvist G. , Brodin L.‐Å.
Published: January 2009

Thirty‐five non‐selected, consenting patients were studied during induction of anesthesia before coronary artery bypass grafting. Anesthesia was induced with diazepam, thiopentone and fentanyl, followed by pancuronium. Before induction, 200 MBq Tc 99 m – HSA was given i.v. and ejection fraction (EF) of the left ventricle was measured with a collimated single‐crystal probe. The patients were allocated to five groups (seven patients in each) treated with: Group A: nitroglycerin i.v. bolus 4 μg x kg‐1 given 30–60 s before laryngoscopy; Group B: nitroglycerin i.v. in continuous infusion, 1 μg x kg‐1 x min‐1 started before induction; Group C: two‐stage topical anesthesia of the vallecula region and larynx with lidocain; Group D: a combination of nitroglycerin and topical anesthesia (as in Group B and C); and Group E: propranolol i.v. 0.01 mg x kg‐1 given 5 min before intubation. All groups reacted in the same way during induction of anesthesia up to the point of laryngoscopy. End‐diastolic volume and systemic arterial pressure decreased while cardiac index remained unchanged and EF increased. During laryngoscopy and intubation, however, differences between the groups were evident. Nitroglycerin i.v. as a bolus effectively prevented a reduction in EF and an increase in left ventricular volume. In addition to these beneficial hemodynamic effects, there was a moderate increase in heart rate and a reduction of stroke index. Continuous infusion of nitroglycerin and propranolol i.v. had no effect, since EF fell and left ventricular volume increased. Patients receiving topical anesthesia demonstrated a blunted response to endotracheal intubation with a moderate decrease in EF and an unchanged (Group C) or slightly increased (Group D) left ventricular volume.
Cardiopulmonary effects of internal cardioverter/defibrillator implantation
Authors: Hachenbero T. , Hammel D. , Möllhoff T. , Brüssel T. , Block M. , Borggrefe M. , Haberecht H. , Scheld H. H. , Wendt M.
Published: January 2009

Cardiopulmonary effects of electrophysiological testing of internal cardioverter/defibrillator (ICD) devices were studied in ten patients undergoing general anaesthesia. In the control‐phase, haemodynamic performance and oxygenation were slightly impaired. After completion of the electrophysiological procedures (ICD‐phase), cardiopulmonary function had deteriorated significantly. Cardiac index declined by 16%, whereas left ventricular filling pressure and pulmonary vascular resistance increased (P≤0.01). Oxygenation, but not CO2‐elimination deteriorated (P≤0.01) and venous admixture increased by 72% (P≤0.01). Alveolo‐arterial Po2‐difference (PA‐aO2) increased by 43% (P≤0.01), indicating ventilation‐perfusion (VA/Q) mismatching. Repeated inductions of ventricular tachycardia and/or fibrillation subject the myocardium to transient global ischaemia, leading to acute congestive heart failure, and positive inotropic intervention was necessary in 40% of the patients. Partial pulmonary insufficiency resulted possibly from interstitial oedema and VA/Q‐inhomogeneities. ICD implantation has detrimental effects on haemodynamics and gas exchange in patients with impaired left ventricular function.
Cardiovascular effects of pregnanolone emulsion: an experimental study in artificially ventilated dogs
Authors: Hogskilde S. , Wagner J. , Strøm J. , Sjøntoft E. , Olesen H. P. , Sørensen M. Bredgaard
Published: January 2009

The acute cardiovascular effects of pregnanolone emulsion, a new steroid preparation for intravenous anaesthesia, were investigated in artificially ventilated dogs. The anaesthetic was administered as repeated intravenous bolus injections, doubling the dosage with each injection. The plasma concentration of pregnanolone, and the haemodynamic, respiratory and metabolic variables were determined after each injection. Cardiac output and heart rate increased from the first bolus dose of the anaesthetic (0.5 mg/kg), which produced anaesthesia lasting 10 to 15 min. Both continued to increase after administration of 1.0, 2.0 and 4 mg/kg, whereas reductions of systemic arterial pressure and estimated myocardial contractility were observed only at the two highest dosages. A decrease in vascular resistance was calculated in the systemic circulation, whereas vascular resistance increased in the pulmonary circulation. A state of circulatory shock followed administration 8, 16 and 32 mg/kg of the anaesthetic.
Basophil histamine release in atopic patients after in vitro provocation with thiopental, Diprivan® and chlormethiazole
Authors: Laxenaire M. C. , Mata E. , Guéant J. L. , Moneret‐Vautrin D. A. , Haberer J. P.
Published: January 2009

The degree of histamine release induced by three different anesthetic drugs was studied in vitro using basophil leukocytes from atopic patients (n = 11) and controls (n = 14). In all, eight dilutions (1/2 to 10‐5) of Diprivan* and its solvent Intralipid*, thiopental and chlormethiazole in aqueous solution, were used. Histamine was released in four controls with weak dilutions (1/2 to 102) of Diprivan (n = 2) and thiopental (n = 2). The reaction with thiopental was greater than that with Diprivan. Five of the atopic subjects released histamine with one or more drug: thiopental and Diprivan four times each, Intralipid twice, and chlormethiazole once. Histamine release was greater in these patients than in controls, and occurred with dilutions ranging from 1/2 to 10‐2, except for one case. It is concluded that atopic patients release histamine with hypnotic anesthetic drugs more easily than normal subjects. In the clinical setting, where blood concentration of the drugs studied is equivalent to a dilution of less than 103, they do not release much histamine. They may be used in atopic patients if the drugs are injected slowly.
Evaluation of 119 anaesthetics received after investigation for susceptibility to malignant hyperthermia
Authors: Ørding H. , Hedengran A. M. , Skovgaard L. T.
Published: January 2009

A questionnaire was sent to the first 371 patients investigated for MH susceptibility at the Danish MH Register, in order to assess sequelae from the muscle biopsy and possible subsequent anaesthetic complications. The purpose was to evaluate both the safety of anaesthetizing MH‐susceptible (MHS) patients without the use of trigger agents, and the safety of giving trigger agents to non‐susceptible (MHN) patients. Eighty‐eight per cent of patients alive replied to the questionnaire. Of these, 22% complained about discomfort at the site of the biopsy, 2% had experienced problems when needing a subsequent anaesthetic, and 0.9% had had trouble when applying for life or accident insurance. The median observation period for all patients following the muscle biopsy was 5.5 years (range 27 months–11 years). During this period, 36 MHS patients had been anaesthetized 52 times (28 general and 23 regional anaesthetics, data missing in one case) without any MH‐related complications. None of the patients had received prophylactic dantrolene. Three MHE patients had received non‐trigger anaesthetic agents on three occasions without development of MH. Thirty‐five MHN patients had been anaesthetized 64 times, and 13 of these MHN patients had received trigger agents 26 times without any signs of MH. An estimate of the probability of clinical MH developing in MHN patients subsequently anaesthetized with trigger agents was found to be 0–24.7% (95% confidence limits), whereas the probability of clinical MH developing in MHS patients anaesthetized with non‐trigger agents was 0–9.7% (95% confidence limits).
Effects of 1.5% glycine solution with and without 1% ethanol on the fluid balance in elderly men
Authors: Hans R. G. , Stalberg H. P. , Ekengren J. , Rundgren M.
Published: January 2009

Ten male patients scheduled for transurethral prostatic resection (aged 57–79) were given irrigating fluid by intravenous infusion at 50 ml·min‐1 over 20 min. Each patient was subjected to two infusions: 1.5% glycine in water on one occasion, and the same solution but with 1% ethanol added on the other. Urine and blood samples were collected at regular intervals for up to 2 h after infusion, and the changes in the distribution of water and electrolytes between fluid compartments were calculated. Transient prickling skin sensations were frequently reported effects of the infusions. Two patients experienced visual disturbances. There were no changes in the blood ammonia and plasma vasopressin levels. During the infusions, the estimated blood volume and the total plasma sodium and potassium content increased. The solutions produced osmotic diuresis with increased urinary excretion of water and electrolytes. After ending the fluid administration, blood volume was rapidly restored. Over the following 120 min the irrigant water was redistributed intracellularly or removed by urinary excretion. The addition of ethanol did not alter the overall effects of glycine solution on the fluid balance.
The relationship between atrial pressure, atrial dimensions and atrial natriuretic factor during pacing tachycardia in dogs
Authors: Riddervold F. , Smiseth O. A. , Bjørnerheim R. , Hall C. , Risøe C.
Published: January 2009

Acute supraventricular tachycardia is known to increase the plasma level of atrial natriuretic factor (ANF). The purpose of these experiments was to investigate if such an increase in plasma‐ANF could be ascribed to changes in atrial pressure and atrial dimensions. Eight anaesthetized dogs were instrumented with atrial pressure catheters and sonomicrometers to measure left and right auricular and atrial free wall dimensions. An acute increase in atrial rate from 150 to 200 min‐1 for 10 min did not change plasma‐ANF or atrial haemodynamic variables. A further increase in atrial rate to 250 or 300 min‐1 increased right and left atrial intracavitary pressures (P<0.01), both auricular diameters and right atrial free wall segment length (P<0.05). Left atrial free wall segment length remained unchanged. Plasma‐ANF increased in all dogs (P<0.01). The change in plasma‐ANF correlated well with changes in atrial pressures as well as with changes in atrial dimensions. These results support the hypothesis that release of ANF during acute atrial tachycardia may in part be attributed to atrial dilatation.
Central circulation during halothane‐diethylether azeotrope and isoflurane anaesthesia in the pig
Authors: Kalman S. , Eintrei C.
Published: January 2009

The fatal anaesthetic ratio (FAR) has been determined for halothane‐diethyl‐ether (HE) in pigs, and the central circulation during hypovolaemia has been investigated using a well‐documented agent such as isoflurane as a standard. The fatal anaesthetic ratio for HE in pigs was (3.21/1.03) = 3.12. This is high compared to the FAR for halothane of 1.7. The central circulation was investigated in 12 pigs which were randomly allocated to either HE or isoflurane anaesthesia, respectively. Baseline values were recorded when they were stable at 1.3 MAC of the volatile anaesthetic used. The pigs were bled 30% of their blood volume, and measurements were made at 5 and 30 min. There was one significant difference between these groups in central circulation: the blood pressure was higher at baseline measurement in the HE group. At 5 min and 30 min, there were no significant differences between these groups. There was a general depression of central circulation without any sign of decreased contractility. HE anaesthesia is well tolerated during hypovolaemia in pigs.
Recovery after total intravenous anaesthesia using combined midazolam/alfentanil infusion and reversal with flumazenil
Authors: Sonne N. M. , Wegmann F. , Crawford M. E. , Boysen K. , Krintel J. J. , Valentin N.
Published: January 2009

One of the major problems with total intravenous anaesthesia (TIVA) is postoperative sedation, possibly with respiratory depression. The aim of the present study was to evaluate the recovery characteristics after TIVA using a continuous infusion of a mixture of midazolam and alfentanil with flumazenil reversal before extubation. This method was compared to balanced anaesthesia using midazolam, alfentanil and nitrous oxide without flumazenil reversal. The degree of sedation was measured by reaction time test, Glasgow Coma Scale, cipher copying test and subtraction test. We found significantly faster reaction times postoperatively in the TIVA group (n = 15) compared to the balanced group (n = 13), despite larger doses of both midazolam (median 21 mg versus 9 mg) and alfentanil (median 5.9 mg versus 4.5 mg). The other tests revealed no difference between the groups. One patient became resedated after flumazenil. We conclude that the TIVA technique described here resulted in slightly better recovery characteristics, offering a usable alternative to balanced anaesthesia.
Peripartum cardiomyopathy: a case report
Authors: Hoffmann A. C. , Masouyé P. , Rifat K. , Suter P. M.
Published: January 2009

Peripartum cardiomyopathy is characterized by congestive left ventricular failure appearing during the last trimester of pregnancy or during the 6 months following delivery, without any specific etiology or pre‐existing cardiac disease. The present report describes the case history of a woman presenting with severe cardiac failure immediately after the delivery of twins.
Hypertonic saline and dextran after coronary artery surgery mobilises fluid excess and improves cardiorespiratory functions
Authors: Tølløfsrud S. , Noddeland H.
Published: January 2009

Background: Extracorporeal circulation induces increased capillary permeability with fluid leakage into the interstitial space, resulting in positive fluid balance and intravascular hypovolaemia. Hypertonic saline 75 mg . ml‐1 in dextran 70, 60 mg . ml‐1 (HSD) seems to be of benefit in patients with impaired perfusion. The purpose of the study was to investigate the effects of HSD infusion on fluid balance and cardiorespiratory functions just after the end of cardiac surgery.

Material and methods: Twenty patients with 3‐vessel coronary artery disease undergoing elective coronary artery bypass surgery were studied. A standard regimen for anaesthesia, extracorporeal circulation and monitoring was used. The patients were allocated to receive just after the end of surgery either HSD or isotonic saline (4 ml . kg‐1 during 30 min) at random in a doubleblind single infusion. Ringer's acetate solution was added as needed to stabilise haemodynamics postoperatively.

Results: HSD caused mobilisation of the retained intraoperative fluid excess, and increased diuresis. Despite reduced need for extra fluid and a decreased cumulative fluid balance, after HSD infusion patients had increased filling pressures of the heart and improved cardiac output. HSD infusion also induced reduced intrapulmonary venous admixture and improved PaO2 in the early postoperative period.

Conclusions: The present study documents that infused hypertonic saline with dextran just after the end of cardiac surgery resulted in mobilisation of the intraoperative fluid excess with increased urine output in the early postoperative period and improved gas exchange. Despite reduced need for extra i.v. fluid and decreased cumulative fluid balance, after HSD infusion the patients had increased filling pressures of the heart with improved cardiac output.
Influence of arterial carbon dioxide tension on systemic vascular resistance in patients undergoing cardiopulmonary bypass
Authors: BuhreM.D W. , Weyland A. , Grüne F. , derVelde J. van , Schorn B. , Kazmaier S. , Sonntag H.
Published: January 2009

Background: The effects of induced hypothermia in cardiac surgical patients are not yet fully understood. Despite numerous studies on the effects of acid‐base management on organ blood flow, only little information is available on the effects of α‐stat versus pH‐stat management on systemic haemodynamics. We therefore compared the effect of a‐stat and pH‐stat acid‐base management on systemic haemodynamics in a prospective, controlled, cross‐over study.

Methods: Twenty patients undergoing coronary artery bypass surgery were included in the study. Cardiac output was measured by thermodilution. Cardiac index and systemic vascular resistance were calculated according to standard formulae. Measurements were performed under hypo‐ and hypercapnia after induction of anaesthesia. Measurements were repeated at the end of two 30‐min periods of pH‐stat and α‐stat acid‐base management, respectively.

Results: Systemic vascular resistance at the lower PaCO2‐levels (hypocapnia and α‐stat, respectively) was significantly higher than those at the higher level (hypercania and pH‐stat, respectively). The periods of different PaCO2‐levels were comparable with respect to haematocrit, blood viscosity and temperature. Systemic vascular resistance was not significantly different from the control period.

Conclusions: This study demonstrates that during hypothermic cardiopulmonary bypass, systemic vascular resistance underα‐stat acid‐base management is higher than under pH‐stat management. As obvious from measurements during the control period, this finding can be completely explained by the difference in PaCO2.
Central and mixed venous blood oxygen correlate well during acute normovolemic hemodilution in anesthetized pigs
Authors: Schou Dr.H. , DeSa V. Perez , Larsson A.
Published: January 2009

Background: Central venous oxygen saturation (ScvO2) and oxygen tension (pcvO2), obtained from the superior vena cava, correlate well with mixed venous (pulmonary arterial) oxygen saturation (SvO2) and tension (pvO2) when the hematocrit is normal. The present study was undertaken to assess whether extreme hemodilution affects this relation.

Methods: We compared mixed and central venous blood during graded arterial desaturation (inspired fraction of oxygen (FIO2) between 1.0 and 0.10) in 10 hemodiluted pigs, and in 10 pigs with normal hematocrit (control), during fentanyl‐ketamine‐pancuronium anesthesia and mechanical ventilation.

Results: Arterial oxygen saturation decreased from 100% at FIO2=1.0 to 44 ± 12% at FIO2=0.10 (mean ± SD). Venous oxygen saturation ranged from 3.5% to 97.3%. The regression coefficient between SvO2 and ScvO2 was 0.97 (R2= 0.93, bias ‐2.4 ± 5.8%) in the hemodiluted and 0.99 (R2= 0.97, bias ‐3.0 ± 5.0%) in the control group. Venous oxygen tension values ranged from 0.5 kPa to 9.5 kPa, and the regression coefficient for oxygen tension was 0.94 (R2= 0.89, bias ‐0.20 ± 0.47 kPa) in the hemodiluted and 0.99 (R2= 0.97, bias ‐0.43 ± 0.48 kPa) in the control group. The regression coefficient for pH was 0.95 in the hemodiluted and 0.98 in the control animals.

Conclusion: The findings indicate that also during hemodilution monitoring of central venous blood oxygen may be as useful as monitoring of mixed venous blood oxygen.
Transfusion policies in coronary artery bypass — a nationwide survey in Finland
Authors: Kytölä L. , Nuutinen L. , Myllylä G.
Published: January 2009

Background: Since the discovery of HIV, minimizing the use of donor blood has become increasingly important in surgical activity. In Finland, however, the use of homologous red blood has grown considerably during the past years. Therefore, we found it necessary to conduct a nationwide survey of transfusion practices in elective surgery. This report deals with transfusions in coronary artery bypass (CABG) operations in all Finnish cardiac centres.

Methods: The study group comprised 804 primary CABG patients operated during a 2‐year period. Two reviewers retrospectively examined the data concerning the use of and indications for homologous and autologous blood in the patient charts.

Results: In all, 705 (88%) of patients received homologous blood. The proportions of patients receiving blood components differed between hospitals: from 53 to 99% for red cells, 2 to 22% for fresh frozen plasma and 5 to 49% for platelets. The variation was not caused by diverse patient populations: the mean number of blood component units transfused per patient differed from 1 to 6 between centres — even after adjustment for confounding variables. Multiple blood conservation methods were used in one centre. Nevertheless, homologous blood was administered to 88% of their patients.

Conclusions: A considerable proportion of CABG patients are transfused with homologous blood in Finland compared to other countries. In addition, the transfusion practices proved highly variable between hospitals and were determined largely by local opinions. This study reveals a clear demand for prospective studies and constructive discussion among anaesthesiologists to establish uniform guidelines for blood use in cardiac surgery.