bluuebunny/crossref_metadata_2025 huggingface dataset:
Treatment of Pain by Transcutaneous Electrical Stimulation
Authors: Magora F. , Aladjemoff L. , Tannenbaum J. , Magora A.
Published: January 2009

Two hundred and ninety‐two patients suffering from a wide range of pain syndromes were treated with transcutaneous electrical stimulation (TES). Electrical stimulation of the painful area was administered on the skin by externally applied electrodes, attached to a portable battery‐operated apparatus. The results, determined according to a subjective scoring system, were good in 50.7%, moderate in 24.3% and poor in 25% of the patients. TES is a non‐invasive technique, has no side effects and may easily be self‐administered. It is concluded that it should be tried in pain syndromes for which no specific therapy is available.
Plasma Free Norepinephrine and Epinephrine Concentrations Following Diazepam‐Ketamine Induction in Patients Undergoing Cardiac Surgery
Authors: Kumar S. M. , Kothary S. P. , Zsigmond E. K.
Published: January 2009

Ketamine causes cardiovascular stimulation, presumably, by increasing central sympathetic activity. This study was undertaken to find out if diazepam in appropriate doses could abolish or moderate the central sympathetic and cardiovascular stimulation following ketamine in patients undergoing cardiac surgery.

Twelve patients, scheduled for valvular replacement (8) and direct aortocoronary bypass graft operations (4) were studied. After premedication with diazepam 0.15 mg/kg orally and morphine sulphate 0.15 mg/kg i.m., they were induced with diazepam 0.3 mg/kg i.v., followed 10 min later by ketamine 2 mg/kg i.v. Direct arterial pressure by a strain gauge from the radial artery and heart rate by EKG were continuously recorded. Plasma free norepinephrine, measured by Vendsalu's method, in the arterial blood was 0.39±0.03 ng/ml prior to induction, 0.39±0.03 ng/ml 10 min after diazepam and 0.42±0.05 ng/ml (P>0.05) 5 min after ketamine administration. Plasma free epinephrine concentrations were 0.10±0.04 ng/ml prior to induction, 0.06±0.03 ng/ml (P>0.05) 10 min after diazepam and 0.01±0.003 ng/ml (P<0.05) 5 min after ketamine. Heart rate and systolic pressure did not change significantly throughout the study period. Diastolic pressures were elevated significantly (P<0.05) 5 min after ketamine administration, amounting to a 12% increase over baseline.

Diazepam‐ketamine induction in cardiac surgical patients did not result in clinically significant central sympathetic or cardiovascular stimulation.
The Clinical Character of Local Anesthetics: A Function of Frequency‐Dependent Conduction Block
Authors: Scurlock J. E. , Meymaris E. , Gregus J.
Published: January 2009

It is a clinically recognized fact that some local anesthetics have a proclivity for inhibition of motor nerves, while others preferentially affect sensory and sympathetic fibers. On the basis that sensory fibers have a frequency threshold for transmission of nociceptive stimuli and that somatic motor fibers have no such frequency threshold, we hypothesized that this variation may be due to differences in the effect of local anesthetics on axonal refractory period. Frog sciatic nerves were partially blocked with lidocaine, bupivacaine, tetracaine and etidocaine, and then stimulated in trains of 17 pulses, at frequencies between 3 and 100 Hz. The height and area of the last action potential in a train were measured. At a comparable level of partial block (50% at 100 Hz), tetracaine and etidocaine showed only a 10% difference between 3 and 100 Hz, while with bupivacaine and lidocaine there was a 30% drop between these two frequencies. This excellent correlation between the laboratory and clinical phenomenon supports our hypothesis. Local anesthetics which have a minimal effect on the refractory period yield enhanced motor block; whereas local anesthetics with a large effect on the refractory period are relatively more potent blockers of sensory and sympathetic transmission.
Systemic Reactions to Tourniquet Ischaemia
Authors: Modig J. , Kolstad K. , Wigren A.
Published: January 2009

In 15 patients, mean age 60 years, undergoing knee arthroplasty under lumbar epidural analgesia, changes in EGG, blood pressure, blood gases, serum potassium, acid‐base status and serum creatine‐phosphokinase were studied following release of a tourniquet applied for 70–135 min. During and after the ischaemia, the skin temperature of the leg operated on was monitored.

Although dextran‐70 was rapidly infused following tourniquet release, the blood pressure decreased significantly, due to a reduction in peripheral resistance. There were no signs of myocardial or pulmonary disturbances. Serum potassium in arterial blood increased significantly and reached a peak 3 min after tourniquet release. There was a tendency to metabolic acidosis, most pronounced after 3 min and caused by local lactate production. The skin temperature of the ischaemic leg fell progressively, which, combined with muscular relaxation, indicates a low metabolic rate. There was no evidence of local ischaemic muscular injury. It is concluded that the systemic changes after interruption of up to 2 h of tourniquet ischaemia are moderate and reversible, even in the elderly.
Cardiac Function During Induction and Early Anesthesia with Methoxyflurane. An Evaluation Using Systolic Time Intervals and Pressure Time Indices
Authors: Sørensen B. , Rasmussen J. P. , Dauchot P. J. , Regula G.
Published: January 2009

In addition to the standard monitoring of heart rate and blood pressure, the Systolic Time Intervals were used to evaluate cardiac performance, and the Pressure Time Indices (tension time index = TTI; diastolic pressure time index = DPTI) were used to estimate myocardial oxygen balance. Twelve patients with known heart disease were studied during induction with thiopental, intubation, and early anesthesia with methoxyflurane.

Cardiac performance diminished after thiopental; and during methoxyflurane it was reflected in increases in pre‐ejection period (PEP) and the ratio PEP/LVET. Intubation resulted in a hyperactive state of the heart, as shown by maximal decreases in PEP and PEP/LVET.

Myocardial oxygen balance ‐ estimated from the supply/demand ratio (DPTI/ TTI) ‐ was impaired after thiopental. After intubation, DPTI/TTI decreased to its lowest value due to an excess of myocardial oxygen demand (TTI) over myocardial oxygen supply (DPTI), signifying a transitory underperfusion of the subendocardium. During methoxyflurane the oxygen balance was gradually restored towards control value.

The Systolic Time Intervals and the Pressure Time Indices provided valuable information on cardiac function not available from standard monitoring alone.
The Use of Ephedrine for Prevention of Arterial Hypotensioi during Epidural Blockade: A Study of the Central Circulation after Subcutaneous Premcdication
Authors: Engberg Greta , Wiklund Lars
Published: January 2009

The changes in central circulation following high epidural blockade in middle‐aged and elderly patients after subcutaneous premedication with ephedrine were compared with changes in patients not given ephedrine. The study was performed prior to elective surgery, after sedation with morphine and scopolamine. The circulatory effects of ephedrine premedication during epidural blockadc with local anaesthetics containing adrenaline, viz. bupivacaine 0.5% with adrenaline and etidocainc 1% with adrenaline (both with an adrenaline concentration of 5 μg.ml‐1), were compared with those obtaincd with a local anacsthetic agent without adrenaline, ctidocainc plain 1%. Ephedrine prcmcditation prevented marked hypotension following epidural blockade in all groups, the prcssor effcct being most pronounccd when adrenaline was included in the local anacsthetic solution. This adrenaline tended to increase the heart rate and cardiac output during the first 30 min and significantly decreased total peripheral resistance. The cardiac effects of adrenaline were not altered by ephcdrine. Ephedrine also prevented the bradycardia and reduction of cardiac output that tended to occur during epidural blockade of the upper two thoracic segments. The pressor effect of ephedrine premedication during high cpidural analgesia seemed to be due mainly to an increased total peripheral resistance when bupivacainc adrenaline or ctidocaine adrenaline was used, but with the use of ctidocainc plain it see med to be mediated by cardiac factors. The total peripheral resistance, however, was not increased to the preanalgesic value and the left ventricular minute work did not rise above the preanalgesic value.
The Circulatory Effects of Intravenously Administered Ephedrine during Epidural Blockade
Authors: Engberg Greta , Wiklund Lars
Published: January 2009

The changes in central circulation following a small dose of intravenously administered ephedrine were Ftudicd in middle‐aged and elderly patients during high epidural blockade with bupivacainc 0.5% with adrenaline, etidocaine 1% with adrenaline, and etidocaine 1% plain. Intravenously injected ephedrine restored the mean, systolic and diastolic arterial blood pressures to the preanalgesic value independent of the degree of hypotension, and was not followed by marked hypcrtcnsion in any case. Although the heart rate did not change, the cardiostimulatory effects were more pronounced than after subcutaneous premedication, resulting in increased stroke volume and cardiac output in all groups. Peripheral vascular resistance increased to the preanalgesic value in the groups receiving bupivacaine adrenaline and etidocaine plain. In the etidocaine adrenaline group, peripheral vascular resistance was little changed, as the cardiostimulatory effects were more pronounced than in the other groups.
Postoperative Haemodynamics in Patients With and Without Cardiac Disease
Authors: Sörensen M. Bredgaard , Bille‐Brahe N. E. , Engell H. C. , Fölsgaard S. , Ernst Jonna
Published: January 2009

The cardiovascular reaction to primarily major vascular surgery was examined in 39 patients without cardiac disease and in 11 patients with cardiac disease.

In the immediate postoperative period (24 h), patients without cardiac disease showed significant increases in heart rate and cardiac index and a decreased blood volume. The central pressures were increased during the first postoperative hour. Systemic blood pressure and vascular resistance remained unchanged, or decreascd slightly. Postoperative haemodynamics in patients with cardiac discase followed the same trends as in normal patients; there were, however, no significant changes in cardiac index or central pressures, and in general the cardiovascular reaction to operation was less conspicuous than in the group of normal patients. The pre‐operative haemodynamic differences between the two groups were diminished in the immediate postoperative period because therapy could be guided by measuring central pressures.
Transcutaneous Oxygen Tension Measurement I. Age Variation and Reproducibility
Authors: Göthgen I. , Jacobsen E.
Published: January 2009

In 20 patients, aged 19–80 y and without pulmonary or cardiovascular disease, transcutaneous oxygen tension (tcPo2) and arterial oxygen tension (Pao2) were measured. tcPo2 was measured with a Radiometer® TCM‐I (transcutaneous oxygen monitor) at 43 C°.

The age regression for tcPo2 was: tcPo2 = 10.4–0.035 x age (r = 0.406); the rorresponding equation for Pao2 was: 13.8–0.053 x age (r = 0.687). The mean difference between tcPo2 and tcPo2 was 2.6 kPa (s.d. = 0.97) and the ratio tcPo2/ tcPo2, was 0.8.

The accuracy of tcPo2 at the level 5.3–13.2 kPa based on 480 measurements was on the average ±1.28 kPa (maximum± 1.73 kPa) at the 95% confidence level.

The accuracy of tcPo2 measurements is acceptable for clinical use, and in healthy adults tcPo2 reflects tcPo2.
Intravenous Lidocaine as a Suppressant of Persistent Cough Caused by Bronchoscopy
Authors: Christensen V. , Ladegaard‐Pedersen H. J. , Skovsted P.
Published: January 2009

The effect of intravenous lidocaine in the treatment of persistent cough occurring after diagnostic bronchoscopies performed under general anaesthesia was investigated in a controlled clinical trial. The study comprised 28 adults patients, all of whom had regained consciousness after anaesthesia. Fifteen patients were treated with lidocaine (1.5 mg/kg body weight) and 13 patients with placebo (saline). In each patient the intravenously injected dose was repeated once after 5 min.

In 11 of the 15 patients (73%) who received lidocaine coughing ceased, while it continued in all 13 patients in the placebo group. The difference is highly significant (P< 0.001).

None of the patients developed side effects such as hypotension, arrhythmias, central nervous system symptoms or respiratory depression after injection of lidocaine. It is therefore concluded that intravenous lidocaine in man is a safe and useful rough‐suppressant.
Ergotism Treated with Hyperbaric Oxygen and Continuous Epidural Analgesia
Authors: Merrick J. , Gufler K. , Jacobsen E.
Published: January 2009

Eight patients suffering from severe ergotarnine‐induced peripheral ischaemia were transferred to our institution for hyperbaric oxygen treatment after unsuccessful therapy in the primary hospital. The patients were exposed to 3 ATBS oxygen for 1 hour 2–3 times daily and they were given an epidural block for the purpose of analgesia where there was severe pain. The circulation and vitality of tissue were restored in all patients. One had tarsal amputations performed half a year later. Hyperbaric oxygen in combination with epidural analgesia is recommended in severe cases of ergotism.
Serum Diazepam and Serum Creatine Kinase after Intra‐muscular Injection of Diazepam in Two Different Vehicles
Authors: Bank‐Mikkelsen O. K. , Steiness E. , Arnold E. , Hansen T. , Søbye M. , Lunding M.
Published: January 2009

Serum diazepam concentration and serum creatine kinase activity (serum CK) were measured in 35 patients (who were divided into three groups (A, B, and C)), over a period of 24 hours after administration of diazepam. An increase in serum CK was regarded as an indication of local muscle injury.

In group A, diazepam in a polyethyleneoxydricinolate vehicle was injected intramuscularly; in group B, diazepam in a propyleneglycol‐ether alcohol vehicle was injected intramuscularly; and in group C, diazepam was administered orally, combined with intramuscular administration of the vehicle used in group B.

The investigation was double‐blind and randomized.

Serum diazepam absorption expressed as the area under the concentration curve was identical in groups A and C and significantly higher than in group B. Serum CK rose in all groups. The differences among the groups were not significant. There were considerable individual variations in all three groups, and almost half the patients showed no increase in serum CK at all.

No negative correlation was found between serum diazepam and serum CK. Thus no effect of muscle injury—if present—on absorption rate could be demonstrated.
The Effect of Propanidid on Systemic Vascular Resistance in Man
Authors: Klauber P. V. , Christensen V. , Korshin J. , Skovsted P.
Published: January 2009

We have studied the peripheral vascular effect in man of propanidid 6 mg/kg, administered as a bolus injection during cardiopulmonary by‐pass with the aorta cross‐clamped and at constant perfusion flow. Ten measurements in eight patients were performed. A decrease was found in systemic vascular resistance: from 150.7±16.3 to 99.5±10.1 k Pa × s/l. No venous pooling occurred. It is concluded that, in man, propanidid causes a vasodilation which must contribute to the hypotension it causes.
Percutaneous Catheterization of the Internal Jugular Vein
Authors: Korshin J. , Klauber P. V. , Christensen V. , Skovsted P.
Published: January 2009

Two techniques for catheterization of the internal jugular vein are described in detail. In a group of 108 adults and 54 children, catheterization of the internal jugular vein was attempted 168 times. Failure to achieve catheterization occurred 12 times. The success rate for the first 50 patients was 86%, but it increased with experience, and was nearly 96% for the remaining patients. Almost 90% of catheterizations were achieved on the first or second attempt. The success rate was understandably lower in the children's group. Catheter malpositioning occurred infrequently (six times) and was most common in the children's group. There were few complications, although two were of a serious nature. The techniques described are straightforward, easy to master and perform, and are recommended as useful additions to the anaesthetist's clinical armamentarium.
Haemodynamic Effects of Enflurane in Patients with Valvular Heart Disease
Authors: Christensen V. , Sørensen M. B. , Klauber P. V. , Skovsted P.
Published: January 2009

In eight patients undergoing cardiac surgery for aortic and/or mitral valvular disease, mean arterial blood pressure (MAP), central venous pressure (CVP), cardiac index (CI), stroke index (SI), pulmonary capillary wedge pressure (PCWP), and pulmonary arterial mean pressure (PAMP) were measured after premedication with diazepam‐scopolamine (I), after breathing 100% oxygen (II), and on controlled respiration (111) after induction of anaesthesia with enflurane‐02, and endotracheal intubation facilitated by succinylcholine.

All measurements were done prior to surgery. Enflurane anaesthesia was found not to affect cardiac index. The average SI decreased by 27%, but was compensated for by an average increase in heart rate (HR) of 33%. The average systemic vascular resistance (SVR) decreased by 14%.

All other measured parameters were found to be unaffected by enflurane‐02 anaesthesia. It is concluded that the cardiovascular stability observed in healthy young normals during enflurane anaesthesia is preserved in patients with moderate to severe heart failure, making enflurane an anaesthetic agent well suited for patients with cardiac disease.
Postoperative Haemodynamics in Patients With and Without Cardiac Disease
Authors: Sørensen M. Bredgaard , Bille‐Brahe N. E. , Engell H. C. , Følsgaard S. , Ernst Jonna
Published: January 2009

The cardiovascular reaction to primarily niaior vascular surgery was examined in 39 patients without cardiac disease and in 11 patients with cardiac disease.

In the immediate postoperative period (24 h), patients without cardiac disease showed significant increases in heart rate and cardiac index and a decreased blood volume. The central pressures were increased during the first postoperative hour. Systemic blood pressure and vascular resistance remained unchanged, or decreased slightly. Postoperative haemodynamics in patients with cardiac disease followed the same trends as in normal patients; there were, however, no significant changes in cardiac index or central pressures, and in general the cardiovascular reaction to operation was less conspicuous than in the group of normal patients. The pre‐operative haemodynamic differences between the two groups were diminished in the immediate postoperative period because therapy could be guided by measuring central pressures.
Heart Rate Changes Caused by Enflurane and Halothane Anaesthesia in Man
Authors: Heiberg J. K. , Wiberg‐Jørgensen F. , Skovsted P.
Published: January 2009

Changes in heart rate and arterial pressure caused by enflurane and halothane anaesthesia were investigated in patients premedicated with diazepam and scopolamine. Enflurane caused a significant (12%) increase in heart rate and depression of arterial pressure (23%). Halothane depressed heart rate significantly (14%), whereas arterial pressure was unaffected. The authors conclude that enflurane possesses a positive chronotropic effect.
Accuracy and Reproducibility of Arterial Blood‐Gas and pH Measurements
Authors: Ladegaard‐Pedersen H. J.
Published: January 2009

In 30 patients blood samples were taken from both radial arteries and analysed for Pco2, Po2, and pH. The influence of sampling technique on the accuracy of blood‐gas analysis was determined. The 95% confidence limits for PCo2 measurements were ±0.32 kPa (2.4 mmHg), and for Po2 measurements were ± 1.16 kPa (8.8 mmHg) in the range below 20 kPa, and ±2.94 kPa (22.0 mmHg) above 20 kPa. For pH, the 95% confidence limits were ±0.014. Only the Po2, measurements were significantly influenced by the sampling procedure.
Transcutaneous Oxygen Tension Measurement 11. The Influence of Halothane and Hypotension
Authors: Gøthgen I. , Jacobsen E.
Published: January 2009

The influence of halothane‐oxygen mixtures on three different transcutaneous oxygen electrodes was investigated. The influence of hypotension caused by halothane and halothane‐nitroprusside on transcutaneous oxygen tension measurement (tcPo2) in halothane‐anaesthetized patients was examined as well. The electrodes differed with respect to polarization voltages (630 mV or 500 mV) and electrolyte composition (silver chloride or silver bromide).

A change dependent on halothane concentration was demonstrated in the electrode readings, both with a polarization voltage of 630 mV and with silver bromide as electrolyte. Using an electrode with 500 mV in polarization voltage and silver chloride as electrolyte, no changes were observed in the readings.

During induced hypotension, the tcPo2 values fell in proportion to the mean arterial blood pressure. In patients with a mean arterial blood pressure over 11 kPa a tcPo2/Pao2 ratio of 0.6 was found.

It is concluded that tcPo2 monitoring during halothane anaesthesia can be influenced in at least two ways, apart from changes in Pao2: (1) by oxygen electrode error due to the halothane; and (2) by changes in skin blood flow.

In comparison to the changes in tcPo2 due to the haemodynamic effects of halothane anaesthesia, the changes due to halothane error are small.
Halothane Anaesthesia and Suxamethonium III. Atropine 30 s Before a Second Dose of Suxamethonium During Inhalation Anaesthesia: Effects and Side‐Effects
Authors: Brandt M. R. , Viby‐Mogensen J.
Published: January 2009

The protection against bradycardia afforded by atropine given intravenously just prior to a second dose of suxamethonium during halothane inhalation anaesthesia was studied in 100 healthy, adult patients randomly allocated to one of five groups characterized by dosage of atropine.

ECG monitoring was continuous, and regular determinations were made of serum potassium, Paco2, Pao2, and blood pressure.

Slowing of the heart rate was seen in more than 50% of patients in each group, but bradycardia (heart rate <60 beatslmin) was seen only in patients receiving the lowest dose of atropine ‐ 0.0075 mg/kg. In the other four groups (atropine 0.01 mg/kg‐0.02 mg/kg), bradycardia prophylaxis was effective, but at the cost of serious ventricular arrhythmias in 15% of the patients. The incidence of these arrhythmias seemed to increase with increasing atropine dosage. Marked tachycardia was also seen.

Because of the incidence of side effects in this and other studies, no absolute recommendation can be made about suxamethonium bradycardia prophylaxis during halothane inhalation anaesthesia, but our present experience suggests that atropine in a dose not exceeding 0.01 mg/kg, given 30 s prior to a second dose of suxamethonium is best.
Intravenous Lidocaine as a Suppressant of Persistent Cough Caused by Bronchoscopy
Authors: Christensen V. , Ladegaard‐Pedersen H. J. , Skovsted P.
Published: January 2009

The effect of intravenous lidocaine in the treatment of persistent cough occurring after diagnostic bronchoscopies performed under general anaesthesia was investigated in a controlled clinical trial. The study comprised 28 adults patients, all of whom had regained consciousness after anaesthesia. Fifteen patients were treated with lidocaine (1.5 mg/kg body weight) and 13 patients with placebo (saline). In each patient the intravenously injected dose was repeated once after 5 min.

In 11 of the 15 patients (73%) who received lidocaine coughing ceased, while it continued in all 13 patients in the placebo group. The difference is highly significant (P< 0.001).

None of the patients developed side effects such as hypotension, arrhythmias, central nervous system symptoms or respiratory depression after injection of lidocaine. It is therefore concluded that intravenous lidocaine in man is a safe and useful cough‐suppressant.
Ergotism Treated with Hyperbaric Oxygen and Continuous Epidural Analgesia
Authors: Merrick J. , Gufler K. , Jacobsen E.
Published: January 2009

Eight patients suffering from severe ergotamine‐induced peripheral ischaemia were transferred to our institution for hyperbaric oxygen treatment after unsuccessful therapy in the primary hospital. The patients were exposed to 3 ATBS oxygen for 1 hour 2–3 times daily and they were given an epidural block for the purpose of analgesia where there was severe pain. The circulation and vitality of tissue were restored in all patients. One had tarsal amputations performed half a year later. Hyperbaric oxygen in combination with epidural analgesia is recommended in severe cases of ergotism.
Theoretical Considerations on the Potential Hazards of Hyperventilation During Anaesthesia
Authors: Sørensen S. C.
Published: January 2009

The purpose of this paper is to evaluate the effect of hyperventilation on cerebral oxygenation. The best estimate of cerebral oxygenation is cerebral venous Po2 (Pvo2). Po2 has been considered in relation to Paco2, during normoxaemia. In order to compare the effects of hyperventilation with the effects of hypoxaemia, Pvo2 has also been considered in relation to Pao2, when Paco2 is constant. Thc results indicate that the low Paco2 values which may be seen in the operating room with manual ventilation have the same effect on cerebral oxygenation as severe hypoxaemia.

It is emphasized that the brain is better protected against threats to cerebral oxygenation, e.g. hypotension, if Pao2, is kept close to normal during anaesthesia. During neurosurgical anaesthesia the advantages of excessive hyperventilation must be weighed against the threat it poses to oxygenation in healthy areas of the brain.
I. Thoracic Epidural Analgesia An Experimental Study in Sheep of the Effects on Central Circulation, Regional Perfusion and Myocardial Performance during Normoxia, Hypoxia and Isoproterenol Administration
Authors: Ottesen S. , Renck H. , Jynge P.
Published: January 2009

Some circulatory effects of thoracic epidural analgesia (TEA) were investigated in splenectomized, open‐chest sheep during normoxia, hypoxia and isoproterenol administration. During normoxia, TEA caused comparatively marked reductions in systemic arterial blood pressure, total peripheral resistance and cardiac output. A fall in heart rate was not compensated for by any rise in stroke volume. Myocardial contractility (LV dp/dt/IP) was not affected by TEA. The proportion of cardiac output diverted to the blocked area was markedly increased. Compensatory vasoconstriction was not observed within the unblocked area in six out of nine animals. Myocardial blood flow showed a pronounced reduction in accordance with the calculated changes of heart work, so that myocardial oxygen extraction remained unchanged.

Studies under hypoxia revealed that cardiac responses to hypoxia in the sheep are mediated chiefly by neurogenic factors. TEA abolished the hypoxia‐induced rise in heart rate but did not affect the increase in pulmonary vascular resistance caused by hypoxia.

The administration of isoproterenol during TEA increased systemic arterial blood pressure, but due to further fall in total peripheral resistance it was not fully normalized. Cardiac output and heart rate increaied markedly. Myocardial oxygen consumption and blood flow increased but did not reach control levels.
II. Haemodynamic Alterations Secondary to Lumbar Epidural Analgesia and their Modification by Plasma Expansion and Adrenaline Administration An Experimental Study in the Sheep
Authors: Ottesen S. , Renck H. , Jynge P.
Published: January 2009

Haemodynamic alterations secondary to the induction of lumbar epidural analgesia (LEA) were investigated in splcnectomized, open‐chest sheep. A considerable reduction in systemic arterial blood pressure (PAa) and total peripheral resistance (TPR) occurred. Cardiac output (Qpa) was reduced non‐significantly as a fall in heart rate (HK) was counteracted by an increase in stroke volume (SV). Myocardial blood flow (MBF) was reduced in parallel with myocardial oxygen consumption (MVO2), so that myocardial oxygen extraction (O2 uc myocardium) remained unchanged. No convincing signs of compensatory vasoconstric‐tion were noticed in the non‐blocked area, and the proportion of QPA diverted to the blocked area (Qap/ca) was increased only non‐significantly.

Administration of dextran 70 was followed by an increase in QPA, mainly due to an increase in SV. PAa increased only slightly as TPR was further reduced. MUF rose only non‐significantly, but O2 uc myocardium increased somewhat. A reduction of vascular resistance in the blocked area was recorded, and in comparison with the control value Qap/ca was markedly increased in most animals.

The effect of adrenaline in three different dosages (0.362, 1.91 and 3.62 μg/min) was studied on the circulatory changes induced by the combination of LEA and dextran administration. The smallest dose resulted in a still further reduction of TPR, but in an increase in Qpa, so that PAa remained unchanged. The two largest dosages resulted in increases in PA2 as Qpa increased with unchanged TPR. It is postulated that the rise of Qpa was a result of improved niyocardial contractility and increased venous return to the heart. MVO2 as well as MBF increased, but O2 uc myocardium was unchanged.

Plasma expansion alone is considered insufficient to counteract the systemic arterial hypotension caused by LEA, but the additional administration of adrenaline in dosages of around 0.1 μg/kg/min restores systolic arterial blood pressure without any untoward effects upon regional perfusion.
Effects of Enflurane on Haemodynamics and Oxygen Consumption in the Dog with Special Reference‐ to the Liver and Preportal Tissues
Authors: Irestedt L. , Andreen M.
Published: January 2009

The effects of enflurane anaesthesia on central circulation, total oxygen uptake, splanchnic circulation and splanchnic oxygen uptake were studied in 10 artificially ventilated dogs, basally anaesthetized with thiopental and nitrous oxide. Hepatic arterial, superior mesenteric arterial and portal venous blood flows were measured with electromagnetic flowmetry. Cardiac output was measured by thermodilution. Determinations of oxygen contents were made in arterial, pulmonary arterial, portal venous and hepatic venous blood. The end‐tidal enflurane concentration was kept at about 1 MAC (= 2.2%). Arterial blood pressure diminished to 54% of control value due to decreases of cardiac output to 65% and of total peripheral vascular resistance to 81% of control values. Hepatic arterial, superior mesenteric arterial and portal venous blood flows decreased to 65–70% of control levels and the corresponding vascular resistances all declined to about 80–85% of control values. Total oxygen uptake decreased, but less than cardiac output, leading to an increased arterio‐venous oxygen content difference. Oxygen uptake of the preportal tissues was unchanged and hepatic oxygen uptake was not significantly altered, although there were decreases in hepatic oxygen uptake in some of the individual experiments. It is suggested that the cardiovascular depression following enflurane anaesthesia in the dog was due, to a great extent, to a primary myocardial depression. It is further roncluded that the splanchnic blood flows were relatively well preserved, due to decreases in splanchnic vascular resistancm, and that hepatic and preportal tissue oxygen consumptions were maintained by increased oxygen extraction.
Paresthesiae or No Paresthesiae? Nerve Lesions after Axillary Blocks
Authors: Selander D. , Edshage S. , Wolff T.
Published: January 2009

Seeking paresthesiae when performing a peripheral nerve block may increase the risk of post‐anesthetic neurological sequelae. To test this hypothesis, we prospec‐tively followed two groups of patients who underwent hand surgery with an axillary block. In one group, the axillary plexus was located by actively seeking paresthesiae; in the other, pulsations of the axillary artery indicated an adequate position of the injection needle. Mepivacaine 10 mg/ml, with or without adrenaline, was used. The study included 533 patients, 290 in the paresthesia group and 243 in the artery group.

Although unintentional, paresthesiae were elicited in 40% of patients in the artery group. Postanesthetic nerve lesions were seen in ten patients, eight in the paresthesia group and two in the artery group, all of whom had been blocked by mepivacaine with adrenaline. Symptoms varied between light paresthesiae lasting a few weeks, and severe paresthesiae, ache and paresis lasting more than 1 year. The etiology suspected was needle and perhaps injection trauma to the nerves during blocking. We conclude that whenever possible nerve blocks should be performed without searching for paresthesiae.
The Foam Nose—A New Disposable Heat and Moisture Exchanger: A Comparison With Other Similar Devices
Authors: Revenäs B. , Lindholm C. E.
Published: January 2009

The Foam Nose (Kemi‐Intressen AB), a heat‐ and moisture exchanger (HME), was compared with two other commercially available HMEs with respect to its heat and moisture exchanging capacity. During steady state, 77% of the expired humidity is restored to the airways with the Foam Nose, 63% with HME Yortex and 63% with HME Dameca.
Restlessness and Shivering after Naloxone Reversal of Fentanyl‐supplemented Anaesthesia
Authors: Tammisto T. , Tigerstedt I.
Published: January 2009

To study the significance of normalization of ventilatory or thermal homeostasis during naloxone reversal, 95 patients were given naloxone after thiopental‐N2O‐O2‐relaxant anaesthesia supplemented with fentanyl (6 μg/kg/h). If naloxone 0.16 mg was given to combat postoperative apnoea during hypercapnia (end tidal carbon dioxide concentration (ETco2) 8%), minute ventilation and respiratory rate were significantly higher during the first minutes as compared to the normo‐capnic patients. Shivering occurred in 44% in the hypercapnic group, as compared to about 30% if naloxone was given during normocapnia (ETco25%). Postoperative pain and restlessness were significantly increased in the hypercapnic group. During normocapnia, untoward reactions were less frequent (40%) if naloxone was given in smaller increments (0.08+0.08 mg) rather than in one dose (0.16 mg) (72%). This was mainly due to nausea (8% compared to 32%). The incidence and severity of shivering showed a positive correlation to the duration of anaesthesia (r = 0.42) and to the total amount of fentanyl (r = 0.32), but not to the actual postoperative oesophageal temperature (r=—0.13).

The results indicate that though untoward reactions after naloxone reversal are aggravated by naloxone‐induced normalization of deranged homeostatic mechanisms, their aetiology probably should be sought in an acute abstinence syndrome.
The Effect of Local Anaesthetic Agents on the Contractility of Human Myometrium in Late Pregnancy: An in Vitro Study
Authors: Willdeck‐Lund G. , Nilsson B. A.
Published: January 2009

Four local anaesthetic agents, lidocaine, prilocaine, bupivacaine and etidocaine with and without adrenaline, were tested regarding their influence on the contraction amplitude, tone and frequency of contractions of human myometrium in vitro. All four drugs had a dose‐related inhibitory effect on the amplitude. This was enhanced by adrenaline. The two short‐acting and the two long‐acting agents were tested in equianalgesic doses in a crossover test. Lidocaine and etidocaine had a significantly greater inhibitory effect on the spontaneous myometrial contractions than prilocaine and bupivacaine. With all drugs, except etidocaine, the tone increased with increasing drug concentrations in the bath. The changes in frequcncy were inconsistent.

Based on the concentrations required to produce 50% inhibition, lidocaine, bupivacaine and etidocaine were, respectively, 1.3, 6.5 and 8.3 times more potent than prilocaine; the corresponding figures for the anaesthetic effect on isolated nerves are reported to be 1.5, 5.3 and 5.3.

The inhibitory effect of etidocaine declined with time, in contrast to the other local anaesthetic agents tested.
Additive Effects of Hypothermia and Phenobarbitol upon Cerebral Oxygen Consumption in the Rat
Authors: Hägerdal M. , Keykhah M. , Perez E. , Harp J. R.
Published: January 2009

The quantitative effects of a combination of hypothermia and phenobarbital on cerebral oxygen uptake (CMK) was studied in rats, curarized and artificially ventilated with 70% nitrous oxide in oxygen. Cerebral blood flow (CBF) was measured with a modification of the Kety & Schmidt (1948) technique, using 133xenon as a tracer. Arteriovenous difference in oxygen content over the brain was measured and CMRo2 was calculated. Four groups were studied. Group 1 was a control group. The three experimental groups were injected with phenobarbital intraperitoneally: Group 2 with 50 mg/kg body weight; Group 3 with 150 mg/kg; and Group 4 with 50 mg/kg of phenobarbital, and, in addition, body temperature was lowered to 32°C in this group. CMRo2, in groups 2, 3 and 4 was reduced by 22, 37 and 43%, respectively, compared to Group 1. The changes in CBF were of the same magnitude. In a previous study we have found that CMRo2 decreases by 5% per 1°C decrease in body temperature. The value for CMRo2 in Group 4 is close to the value obtained if the effect of 50 mg/kg body weight of phenobarbital on CMRo2 is added to the effect of a temperature reduction of 5°C.

It is concluded that the effects of barbiturates and hypothermia on CMRo2 are additive.
Method for Continuous Measurement of Carbon Dioxide Output during Anesthesia An Assessment
Authors: Stokke D. B. , Andersen P. K. , Hole P. , Rasmussen N. J. , Waaben J.
Published: January 2009

Employing the Mapleson D circuit, a modified closed‐circuit flow‐through technique for the continuous measurement of carbon dioxide production (Vco2) was tested for accuracy and precision in a lung model. The recovery of carbon dioxide production was found to be between 90 and 1lo%, the maximized errors for a single estimate of carbon dioxide production were between ± 4 and ± 28%, with the highest errors at high gas flows and low carbon dioxide inputs. Accepting arbitrarily chosen limits of maximized errors of ± 10%, it could be shown that the system did not work acceptably when the mean carbon dioxide concentration was below 1.5 vol.% within the fresh gas flow rates (2.2–7.7 1 min‐1) and the range of minute ventilation (4–10 1 min‐1) employed. The half‐life of carbon dioxide washout varied between 41 and 138 s, thus limiting the suitability of the system for detecting changes in carbon dioxide output. The method may be used as an approximate monitor of VCo2 in anaesthetized patients, but cannot be regarded as sufficient for research purposes.
Local Anesthetics: Importance of Mode of Application, Concentration and Adrenaline for the Appearance of Nerve Lesions: An Experimental Study of Axonal Degeneration and Barrier Damage after Intrafascicular Injection or Topical Application of Bupivacaine (Marcah®)
Authors: Selander D. , Brattsand R. , Lundborg G. , Nordborg C. , Olson Y.
Published: January 2009

Local anesthetics are designed for application in or close to nerve tissue. In spite of their wide clinical use, surprisingly few investigations deal with the neural toxicity of modern local anesthetics. In this experimental study, the effects were investigated of intrafascicular or topical application of the long‐acting local anesthetic bupivacaine on the rabbit sciatic nerve. Axonal degeneration was histologically evaluated and a fluorescence‐microscopic technique used to detect lesions in the blood‐nerve barrier. Topical application of bupivacaine in clinically recommended concentrations around the nerve caused no detectable nerve injury, while intrafascicular injections caused considerable axonal degeneration and damaged the blood‐nerve barrier. Axonal degeneration was the same after injection of physiologic saline solution and bupivacaine 0.5%, but it increased with increasing bupivacaine concentration and especially with the addition of adrenaline. On the other hand, the acute effects of intrafascicular injection, as visualized in the barrier experiments, changed little with the addition of adrenaline, indicating that it is the injection trauma itself which is deleterious. It is concluded that intraneural injections should be avoided and that plain bupivacaine solutions should be routinely used.
Regional Lung Function and Central Hemodynamics Following Normovolemic Hemodilution in the Dog
Authors: Rosberg B.
Published: January 2009

Regional lung fnnction, using xenon 133‐radiospirometry, and central hemodynamics were stndied following normovolemic hemodilution with dextran 70. Normovolemic hemodilution to hematocrit values of 25% increased cardiac output and pulmonary blood volume significantly. The systemic oxygen transport and mixed venous oxygen tension were unchanged. The acute hemodilution did not significantly change the distribution of ventilation or perfusion within the lungs. It is hypothesised that a tendency to an increase in arterial oxygenation is due to a reduced interstitial pressure in the basal region of the lungs, resulting from water absorption by the hyperoncotic dextran used for hemodilution.
Effect of Non‐Carbonic Acidosis on Total Splanchnic Perfusion and Cardiac Output During Anaesthesia with O2‐N2O‐Barbiturate‐Relaxant
Authors: Juhl B. , Einer‐Jensen N. , Madsen T.
Published: January 2009

Seven dogs were anaesthetized using mebumal natrium‐O2‐N2O‐gallamoni jodidum. The Paco2was kept at a constant level by means of mechanical ventilation, and non‐carbonic acidosis was induced with HCI infusion (0.3 normal). The arterial pH varied from 7.45 to 6.88. During this acidosis, a rising arterio‐venous oxygen difference was observed, with an unchanged total oxygen consumption. The pulse fell, but the mean pressures in the right atrium and aorta were unchanged. The peripheral resistance rose by 50%, whereas the fall in cardiac output of 20%, was non‐significant (0.10>P>0.05). The total splanchnic perfusion fell by 28%, and the change in flow wa correlated to the change in pH. Total splanchnic perfusion (ml min‐1) = ‐4078 + 655 x pH (N = 42, r = 0.67,P< 0.001). Total splanchnic perfusion as a fraction of the cardiac outpnt remained unchanged. The resistance in the splanchnic area rose by 50%. The oxygen saturation in the portal vein and mixed venous blood changed in parallel. It is concluded that contraction of the blood vessels is the most important effect on the circulation resulting from non‐carbonic acidosis during the anaesthesia employed liere.
Cerebral Circulatory and Metabolic Stimulation with Nitrous Oxide in the Dog Reconfirmation by the Simultaneous Measurement of Ckrebral Blood Flow using Direct and Kety‐Schmidt Methods
Authors: Oshita S. , Ishikawa T. , Tokutsu Y. , Takeshita H.
Published: January 2009

In both the presencc and the absence of nitrous oxide (57%, end‐tidal), cerebral blood flow (CBF) was measured by a direct method in dogs, and compared to an indirect method (Kety‐Schmidt method), using argon as the tracer. Eighteen comparisons were made in five dogs at flows ranging from 45 to 123 ml per 100 g per minute. There was no systematic difference in CBF between the direct and indirect mcthods, and the ratio of direct CBF to indirect CBF was 1.03. The cerebral circulatory and metabolic stimulation effect of N2O in the dog was reconfirmrd.
Arrhythmias During Halothane Anesthesia IV. The Influence of a Single Dose of Suxamethonium
Authors: Andersen J. R. , Eikard B.
Published: January 2009

The effect of a single dose of suxamethonium on cardiac rate and rhythm during halothane anesthesia with barbiturate induction was studied in a prospective, triple‐blind trial with 28 patients. No atropine was given and patients were not intubated.

A slight but significant preponderance of sinus‐bradycardia without hemodynamic consequrnces was found in the group given suxamethonium. Suxametlionium did not provoke ventricular ectopies or conduction disturbanccs.

It is concluded that in anesthesia with barbiturate induction, but without atropine or intubation, the use of a single dose of suxamethonium is a safe procrdure with regard to cardiac rate and rhythm.
ECG Electrodes: A Study of Electrical and Mechanical Long‐term Properties
Authors: Ask P. , ÖDerg P. Å. , ÖDman S. , Tenland T. , Skogh M.
Published: January 2009

The long‐term properties of commercially available ECG‐electrodes were studied by investigating the parameters: polarization potential, electrical impedance, adhesion, and skin reactions during a period of 7 days. As expected, the most stable polarization potentials were obtained for Ag/AgCl electrodes. Certain simple disposable electrodes showed large polarization potential variations. The most stable electrode impedance was obtained for disposable electrodes with stable adhesion and equipped with an electrode cup or similar. Unchanged adhesion and mrrhanical properties during the test period were shown by the disposable clcrtrodcs with a large self‐adhesive collar.
Peak Expiratory Flow During a Passive Exhalation: An Index of Expiratory Resistance During Anesthesia
Authors: Wakakuri H. , Camporesi E. M.
Published: January 2009

During a passive exhalation performed between (FRC + VT) and FRC, peak expiratory flow (VmaxE) varies as a function of the respiratory system expiratory resistance, RT, with the following relationship: Vmax, = VT/(RT CT), where Cr is the total respiratory system compliance (static). This expression assumes: (1) a laminar flow regimen during expiration, and (2) a constant CT value over the range of VT. Both these conditions arc usually attained during controlled ventilation in the apneic patient. VmaxE can be monitored continuously with relative ease, and may represent a simple and useful index of the mechanical properties of the respiratory system in the anesthetized patient.
Arterial Carbon Dioxide Tensions during Anaesthesia with Manual Ventilation A Descriptive Study of the Effects of Various Non‐Polluting Circuits
Authors: Hole P. , Andersen P. K. , Stokke D. B. , Rasmussen N. J. , Juhl B. , Jørgensen S.
Published: January 2009

In 660 supine, intubated and anaesthetized, healthy patients scheduled for various elective surgical procedures, the distribution of arterial carbon dioxide tension (Paco2) was investigated during manual non‐monitored ventilation. The study comprised six equal groups: group I: ventilation with a circle circuit absorber system; group 2: ventilation with the Hafnia A circuit using a total fresh gas flow (FGF) of 100 ml.kg‐1 min‐1; groups 3–6: ventilation with a Hafnia D circuit with fresh gas flows of 100, 80, 70 and 60 ml.kg‐1 min‐1, respectively. The mean Paco's of the first three groups were situated in the lower range of normocapnia (the observations in the first group having the greatest total range), whereas the rebreathing (Hafnia A and D) circuits resulted in a clustering of observed data. Employing the rebreathing circuits, protection against hypocapnia can be achieved by lowering the fresh gas flow. The most satisfying result was obtained with the Hafnia D circuit with a fresh gas flow of 70 ml.kg‐1 min‐1, resulting in normocapnia with a modest and limited spread towards hypo‐ and hypercapnia. FGF in excess of this level must be considered as wasted. The study indicates that corrections of fresh gas flows for age are superfluous. Use of relaxants and type of surgery had no influence on the observations.