bluuebunny/crossref_metadata_2025 huggingface dataset:
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 unaffectcd. The authors conclude that enflurane possesses a positive chronotropic effect.
Transcutaneous Oxygen Tension Measurement II. 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 /tcPo2 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 tcPo2: (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, Po2, Po2 and blood pressure.

Slowing of the heart rate was seen in more than 50% of patients in each group, but bradycardia (heart rate < 60 beats/min) 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.
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 hypcrventilation on cercbral oxygenation. The best estimate of cerebral oxygenation is cerebral venous Po2 (Pvo2). Pvo2 has been considered in relation to Paco2 during nornioxaemia. In order to compare the effects of hyperventilation with the effects of hypoxaemia, Pvo2 has also been considered in relation to Pao2, when Pavco2 is constant. The results indicate that the low Pavco2 values which may be seen in the oprrating 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 Pvco2 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 arras of the brain.
The Haemodynamic Effects of Sodium Nitroprusside‐Induced Hypotension during Beta‐Adrenergic Blockade and Anaesthesia A Case Report
Authors: Beierholm E. A. , Sørensen M. Bredgaard , Thorshauge C.
Published: January 2009

We present the central haemodynamic data obtained during halothane/nitrous oxide anaesthesia in a patient under antihypertensive treatment with propranolol who underwent surgery for intracranial aneurysms in sodium nitroprusside‐induced hypotension. Cardiac output remained unchanged when hypotension was induced. Pulmonary capillary wedge pressure decreased. There was a slight increase in heart rate, as well as a minor decrease in stroke volume. Systemic vascular resistance decreased, but pulmonary vascular resistance remained unchanged. The response observed is discussed.
Transcutaneous Oxygen Tension Measurement I. Age Variation and Reproducibility
Authors: Gøthgen I. , Jcobsen 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 × age (r = 0.406); the corresponding equation for Po2 was: 13.8–0.053 × age (r = 0.687). The mean difference between tcPo2 and Pao2 was 2.6 kPa (s.d. = 0.97) and the ratio tcPo2/ Pao2 was 0.8.

The accuracy of tcPo2 at the level 5.3–13.2 kPa based on 480 measurements was on the averagef 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 tcPo, reflects Pao2.
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 C3diazepam 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.
Two Early Danish Respirators Designed for Prolonged Artificial Ventilation
Authors: Kristensen H. Sund , Lunding M.
Published: January 2009

Two Danish respirators are described. The first one was made by August Krogh in 1931 and was based on the principles of the Drinker tank respirator. The original feature was a motor driven by water from an ordinary water tap. It was never widely used, most likely due to practical problems connected with nursing care, etc.

The polio epidemic in Copenhagen in 1952 initiated the era cf the IPPV‐methods and gave rise to the construction of a great number of new respirators. Among the first of these was the Claus Bang respirator. Although it contained many modern featurcs, it proved technically unreliable and was only used for 3–5 years.
Effects of Neurolept Anaesthesia (NLA) 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 etrects of neurolept anaesthesia (NLA) on central circulation, total oxygen uptake and splanchnic cirrulation and oxygen uptake were studied in 12 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. NLA was induced with droperidol 0.5 mg kg‐1 b.w. and fentanyl 0.01 mg kg‐1 b.w. Arterial blood pressure decreased to 63% of control value due to reductions of cardiac output to 78% and of total peripheral vascular resistance to 81% of control values. Hepatic arterial, superior mesenteric arterial and portal venous blood flows all diminished to 75% of control values. Hepatic arterial, superior mesenteric arterial and preportal tissue vascular resistances all decreased. Total oxygen uptake declined to the same extent as cardiac output, leaving the arterio‐venous oxygen difference unchanged. Oxygen uptake of the preportal tissues was unaffected and hepatic oxygen uptake was not significantly reduced, although there were decreases of hepatic oxygen uptake in some of the individual dogs. It is suggested that the cardiovascular depression following NLA was due to adaptation to a lowered total oxygen uptake. It is further concluded that splanchnic circulation was well preserved due to decreases in splanchnic vascular resistances, and that splanchnic oxygen consumption was maintained by means of increased oxygen extraction.
In‐line Blood Warming and Microfiltration Devices
Authors: Linko K.
Published: January 2009

Homogeneous microaggregate‐free whole blood at +5°C was transfused at constant pressures of 20 and 40 kPa through two micro‐filtration and blood warming devices, and the temperature of the blood was recorded before it reached the venous cannula. The flow rates with the Fenwal® system were 58 and 139 g/min, whereas the micro‐filter MF10B® combined with the Portex® Coil allowed flow rates of 143 and 224 g/min. The warming capacities of the two warmers were almost equal and this did not prove to be their weak point.

The infusion temperature varied considerably during the transfusion. Increasing the priming volume of the coil would raise the mean infusion temperature.

A pressure infusor (Fenwal®) was tested, and the internal pressures of the blood bag and the infusor were determined separately. The bag pressure differed significantly from the infusor pressure as the blood bag emptied, making the usefulness of the infusor manometer questionable.
In‐line Blood Warming and Microfiltration Devices: II. Influence of Blood Temperature on Flow Rate and Hemolysis During Pressure Transfusion Through Microfilters and Transfusion Sets
Authors: Linko K.
Published: January 2009

The influence of blood temperature on flow rate and hemolysis was studied. Homogeneous aggregate‐free blood was transfused through six different micro‐filters and transfusion sets, combined with a large‐bore venous cannula (Venflon® No. 2) at a constant pressure of 20 kPa. Flow rates and plasma hemoglobin for cold (+ 5°C) and prewarmed (+ 37°C) blood were determined separately.

Warming the blood from +5°C to +37°C improved the flow from 49 to 86%. The best flow rates with + 37°C blood were obtained with surface filters (MFlOB®, 275 g/l), and the poorest with depth filters (Swank®, 179 g/l). However, the transfusion set and venous cannula seemed to have more influence on the total flow resistance. The Fenwal “dry‐heat” warmer was found to have a great flow resistance.

The pressure transfusion caused only a slight increase in free plasma hemoglobin of cold blood and no increase in prewarmed blood.

It seems more practical to warm the entire blood unit before transfusion than to use so‐called in‐line blood warmers, because prewarming results in a flow rate approximately twice as high as that obtained with coils.
Post‐mortem Findings of Tracheal Injury After Cuffed Intubation and Tracheostomy: A clinical and histopathological study
Authors: Arola M. K. , Anttinen J.
Published: January 2009

The tracheas of 37 tracheostomizcd patients (31 men and 6 women) were studied in connection with obduction. Twenty‐six patients had been intubated before tracheostomy and 29 of the tracheostomized patients were treated with a respirator. At autopsy, the damage caused to the tracheal wall by the cuff was studied macroscopically; the finding was photographed for later investigation and samples were taken from the damaged area for microscopic examination.

The purpose of the study was to determine the damage caused to the tracheal wall by the low‐volume cuff we have used during the last 4 years. The cuff diameter was nearly the same as that of the trachea.

The injuries were grouped according to their extent and depth as mild, moderate or severe, and the groups contained, respectively, 5, 12 and 20 patients. It seemed that cuff pressure played a greater part in causing damage than the duration of cuff strain. Factors in the clinical condition of patients, like hypotension, uraemia, respiratory infections, sepsis and use of steroids, may have had an effect on the development of damage. The injuries caused by the cuff used are so severe that there is every reason to use instead the low‐pressure, high‐volume cuff, which has been shown to cause less damage, whenever long‐term treatment is involved.
Prognosis after Cardiac Arrest Occurring Outside Intensive Care and Coronary Units
Authors: Wernberg M. , Thomasen A.
Published: January 2009

Emergency calls to a total of 1686 patients with verified cardiac arrest in the University Hospital, Arhus, were made in the 8‐year period 1969–1977. Among the patients, cardiac arrest occurred outside the hospital in 1347, in the general wards in 240, while it was present on arrival at the emergency room in 99. Resuscitation was attempted in 1172 patients; 181 survived for at least 24 hours, and 72 were discharged alive, including 13 with residual brain damage.

The prognosis was best when cardiac arrest occurred in the general wards (13% discharged) and poorest when it occurred outside the hospital (4% discharged). However, in the latter group, the prognosis showed considerable improvement when resuscitation was initiated at once by a doctor or by laymen present at the accident site (16% discharged). As regards the mechanism of cardiac arrest, ventricular fibrillation was found to be a relatively favourable prognostic sign (10% discharged), whereas almost none of the patients with asystole or severe bradycardia survived. The possibility of improving the prognosis of cardiac arrest occurring outside hospital by the establishment of mobile coronary care units and by instructing lay people in the technique of cardiopulmonary resuscitation is discussed.
Hernodynamic Effects of Prenalterol, a β1‐Adrenoreceptor Agonist, in Hypotension Induced by High Thoracic Epidural Block in Man
Authors: Reiz S. , Nath S. , Pontén E.
Published: January 2009

The hemodynamic effects of prenalterol, a new β1‐adrenoreceptor agonist, on hypotension induced by a thoracic epidural block extending between TI and TI2 and thereby blorking the cardiac sympathetic supply have been studied in eight patients scheduled for abdominal aortic aneurysm resection.

The thoracic epidural block induced a drop in blood pressure, due to a reduction in cardiac output and systemic vascular resistance. Intravenous infusion of 10 mg of prenalterol rapidly and effectively reversed the hypotension by an increase in cardiac output without any effects on systemic vascular resistance or heart rate. The results indicate that prenalterol is a pure β1 agonist with a marked inotropic but no chronotropic property.
Warming of Blood Units in Water Bath and Cooling of Blood at Room Temperature
Authors: Linko K. , Palosaari S.
Published: January 2009

Warming of whole blood units in a waterbath is considered too slow for emergencies and also results in a waste of blood. In this study the blood temperature was recorded continuously during warming in various kinds of baths.

The warming of + 5°C CPD blood units (500 g) in a bucket of water was considerably slower than in a stirred and thermostated (+ 39.5°C) water bath, where the blood temperature reached +35°C in 13.4 min. Addition of continuous mechanical agitation of the blood unit raised the temperature to +32°C in 5.0 min, and to + 35°C in 6.6 min. This should be sufficient for most clinical situations. Agitation did not cause significant hemolysis when compared with units warmed without agitation.

The cooling rate of warmed blood (+ 37°C) at room temperature (+ 21°C) was also studied experimentally. The temperature of the blood units fell 3°C in 5 min and 5°C in 15 min. Cooling of blood simultaneously in the bag, microfilter and transfusion set resulted in an infusion temperature of +32°C at the end of the transfusion with a flow rate of 85 g/min. Thus, blood units should be warmed immediately before use. Insulation of the transfusion set may also be practicable.
Comparison of Pituitary‐Adrenocortical Response to Hypoglycaemia and Surgery
Authors: Blichert‐Toft M. , Christiansen C. , Engquist A. , Kehlet H. , Lindholm J. , Hummer L. , Dinesen B.
Published: January 2009

The hypothalamic‐pituitary‐adrenocortical (HPA) responses to the hypoglycaemic stimulus and to operation (laparotomy) are compared. The studies were carried out in eight patients who were subjected to insulin‐induced hypoglycaemia on the day before elective abdominal surgery. Plasma corticotrophin (ACTH) and plasma cortisol concentration increases were virtually identical during the two procedures, which suggests that hypoglycaemia and surgical trauma are comparable stress factors and that the hypoglycaemia test is reliable in predicting the HPA responses to major surgical trauma.
The Potentiation of Halothane Anaesthesia by Clonidine
Authors: Kaukinen S. , Pyykkö K.
Published: January 2009

The antihypertensive agent, clonidine, has a marked sedative effect. We studied whether clonidine also deepens halothane anaesthesia. Eight rabbits were anaesthetized with and without clonidine premedication in a cross‐over study. Clonidine premedication (50 μg/kg subcutaneously) was administered three times daily for 3 days. Tolerance to pain during halothane anaesthesia was tested by compressing the ear with a vessel clamp. Halothane concentrations were determined by gas chromatography. The rabbits premedicated with clonidine tolerated painful stimuli without reactions at lower halothane concentrations in arterial blood and inspired air than unpremedicated rabbits. MAC calculated from blood concentrations was 1.29% for unpremedicated and 1.09% for clonidine‐premedicated rabbits. The results suggest that clonidine diminishes the anaesthetic requirement in halothane anaesthesia.
Preoperative and Postoperative Use of Clonidine with Neurolept Anaesthesia
Authors: Kaukinen S. , Kaukinen L. , Eerola R.
Published: January 2009

The abrupt cessation of clonidine therapy can induce a withdrawal syndrome. This may also appear immediately after anaesthesia if clonidine medication is discontinued during the operation day. We studied (1) whether the withdrawal syndrome occurs postoperatively as often as otherwise when clonidine therapy is discontinued, and (2) the action of this clonidine withdrawal on the circulation as compared to patients who received clonidine without interruption during the operation day. During the recovery period in 2 out of 10 patients in whom clonidine medication was discontinued, a hypertensive crisis occurred, which was relieved by clonidine readministration. Clonidine given with premedication eliminated high rises in blood pressure during anaesthesia. During the recovery period, the regular intramuscular administration of the same dose of clonidine as the patients had used orally decreased blood pressure to almost normotensive levels. The slightly increased urinary catecholamine excretion and plasma renin activity in these patients might, however, indicate that the circulatory homeostasis was disturbed in some degree. The results suggest that it is important to give clonidine continuously, even during the operation day. The dose may be the same as, or preferably somewhat smaller than that which the patients have previously received orally.
Prevalence and Prognostic Significance of Coma after Cardiac Arrest Outside Intensive Care and Coronary Units
Authors: Thomassen A. , Wernberg M.
Published: January 2009

In 181 patients resuscitated from cardiac arrest, the prevalence and duration of coma were registered and related to the site of occurrence of cardiac arrest, cardiac rhythm during arrest, age and clinical outcome of the patients. Coma was most frequent after cardiac arrest outside the hospital, as 84% of these patients were comatose for more than 1 h and 56% for more than 24 h; the corrcsponding values for patients with cardiac arrest in general wards were 63% and 30%, rcspectively, and for patients with cardiac arrest during ambulance transport, 80% and 44%. Permanent brain damage was extremely rare if the coma lasted less than 6 h (1 out of 62 patients), and relatively rare with a coma duration betwecn 6 and 24 h (5 out of 34 patients). Of the patients, 85 remained comatose for more than 24 h and only 7 of them were discharged alive, all with cerebral impairment of a severity increasing with the duration of the coma. None regained consciousness after more than 7 days' coma, and a total of 80 patients died in coma, 20 with signs of cerebral death. Older patients were more vulnerable to coma than younger ones, but coma as such was not more frequent. We found no differences in coma after asystole and ventricular fibrillation. Problems concerning the selection of patients who have a chance of survival, although comatose after cardiac arrest, are discussed.
Effect of Non‐Carbonic Acidosis on Total Splanchnic Perfusion and Cardiac Output During Anaesthesia with O2‐N2O‐Halothane
Authors: Juhl B. , Einer‐Jensen N. , Madsen T.
Published: January 2009

Six dogs, premedicated with pethidine 10 mg kg‐1 b.w., were anaesthrtixd with mebumal natrium (NFN) 25 mg kg‐ 1 b.w. and 80 mg gallarnoni jodidum (NFN). Anaesthesia was continued with O2‐N2O‐halothane and artificial ventilation. Non‐rarbonic acidosis was induced by i.v. infusion of hydrochloric acid, during which the related values of pulse, blood pressure, cardiac output, total splantlinic perfusion and portal pressure were measured.

The pulse remained unchanged down to pH 7.0. At this pH, arrhythmia suddenly occurred and developed into ventricular fibrillation. Before this occurred, falling rardiac output was observed (cardiac output 1 min‐1 = 21.49 + 3.21 x pH, N = 23, r = 0.75, P<0.001) and rising oxygen consumption (O2 ml min‐ 1 kg‐1 = 25.79–2.96 x pH, N = 28, r = 0.52, P<0.01), rising oxygen extraction and rising peripheral resistance, while the mean pressure in the aorta was almost unaltered. During this course towards circulatory failure, an unchanged to slightly rising total splanchnic perfusion (Qspl) was demonstrated, which with the lowest pH, reprrsented up to 40% of the cardiac output (QtOt):

Qsr1/Qtol = 3.11‐0.39x pH (N = 28, r = 0.52, P<0.01) Portal pressure rises slightly during acidosis, and oxygen saturation in tlie portal vein is high. It is probable that the retained splanchnic blood flow is caused by rrtention of the portal flow. This is quite different from observations during anaesthesia with barbiturates. It is conrluded that halothanc modifies considerably the circulatory response in the systemir circulation and the splanchnic region during non‐carbonic acidosis.
The Effect of Positive End Expiratory Pressure after Three Types of Open Heart Surgery
Authors: Harboe S. , Levang O. W. , Hysing E. S.
Published: January 2009

It has previously been shown that patients who have undergone mitral valve replacement (MVR) tolerate a positive end expiratory pressure (PEEP) of 1.0 kPa better than patients who have had aortic valve replacement (AVR). The difference was explained by the fact that the mitral patients had pre‐existing pulmonary vascular disease.

In the present study the effect of PEEP up to 2.0 kPa is investigated in three types of operations: aortocoronary bypass graft (ACBG), mitral valve replacement, and aortic valve replacement; there were five patients in each group. We found that our mitral patients tolerated PEEP better than the two other groups, and that tolerance was not correlated to a higher pulmonary vascular resistance, but rather to a higher level of pulmonary capillary wedge pressure. The influence of PEEP varies in different types of patients and the effect is still difficult to predict.
Long‐and Short‐Term Mortality Rates in Patients who Primarily Survive Cardiac Arrest Compared with a Normal Population
Authors: Wernberg M. , Thomassen A.
Published: January 2009

This is a follow‐up study of 180 survivors after cardiac arrest outside intensive care and coronary care units. The follow‐up extended over 0.5 to 8.5 years (average 4.3 years) after the primary cardiac arrest. Of the patients, 72 (40%) were discharged from hospital, 13 with anoxic brain damage. Thirty‐one per cent of the discharged patients died within the first year; death had occurred in 43% after 2 years, and in 50% after 3 years. After that time, the mortality was similar to that of a comparable normal population. At the end of the study, 34 patients were still alive, including eight with neurological sequelae. Their present cardiac function was satisfactory in the majority (59%) of the patients falling into group I or II of the American Heart Association classification. Their social situation, however, left much to be desired, as only 50% had fully or partly regained their previous level of activity.
Regional Lung Function Following Hip Arthroplasty and Preoperative Normovolemic Hemodilution
Authors: Rosberg B. , Wulff K.
Published: January 2009

The effect of preoperative normovolemic hemodilution with dextran 70 as dilutional agent on postoperative regional lung function was evaluated in patients undergoing hip arthroplasty in the lateral decubitus position. The major part of the surgical blood loss of these patients was replaced with the received autologous blood. The results obtained were compared to changes in a group of patients in whom the operative bleeding was replaced with bank blood.

Regional lung function, as studied with Xe133 radiospirometry, is not negatively influenced by the hemodilution technique. In both groups a reduction in perfusion, ventilation and volume of ventilated alveoli was revealed postoperativcly in the lung that was dependent during surgery, probably caused by impaired ventilation of this lung and peroperatively induced microembolism. A more rapid normalization was found in the preoperatively hernodiluted patients. The reduced volume of bank blood transfused to these patients and/or a protective effect of the preoperatively infused dextran on the microembolism evoked by the surgical trauma might explain this difference between the groups studied.
Influence of Chlormethiazole on Cerebral Blood Flow and Oxygen Consumption in the Rat, and its Effect on the Recovery of Cortical Energy Metabolism after Pronounced, Incomplete Ischaemia
Authors: Carlsson C. , Rehncrona S.
Published: January 2009

The influence of an anaesthetic dose of chlormethiazole (Heminewino) on blood flow (CBF) and oxygen consumption (CMRo2) in the rat brain was investigated. In spontaneously breathing animals a dose of 160 mg.kg‐1 of chlormethiazole, infused i.v., induced a state close to surgical anaesthesia. In paralyzed animals, the same dose decreased CBF and CMRo2 to about 60% of control, an effect similar to that observed after an anaesthetic dose of phenobarbitone. Neither a protective nor a detrimental effect of chlormethiazole could be demonstrated when the drug was given during reversible and pronounced, incomplete ischaemia, as evaluated from the postischaemic tissue concentrations of labile phosphates (PCr, ATP, ADP, AMP) and of lactate and pyruvate. It is concluded that protection in this situation (as earlier shown with phenobarbitone) must, at least partly, be related to other mechanisms than a depression of metabolism.
Epidural Analgesia Inhibits the Renin and Aldosterone Response to Surgery
Authors: Brandt M. R. , ØLgaard K. , Kehlet H.
Published: January 2009

Renin activity and aldosterone concentration in plasma and excretion of sodium and potassium in urine were measured during a period of 24 hours in 12 patients undergoing hysterectomy under general anaesthesia or epidural analgesia. Analgesia extended from T4 to S5 and was effective throughout the study. The normal stress‐induced increase in plasma renin activity and aldosterone was inhibited by epidural analgesia. Urinary excretion of potassium was significantly lower in the epidural group, but sodium and water retention showed no difference between groups. It is concluded that neurogenic stimuli from the surgical area are important release mechanisms of the renin‐aldosterone response to surgery. The results suggest that post‐operative sodium retention is caused by factors other than the mineralocorticoid system.
Anaphylaxis in the Monkey: Respiratory Mechanics, Acid‐base Status and Blood Gases
Authors: Revenäs B. , Smedegård G. , Arfors K.‐E.
Published: January 2009

Aggregate anaphylaxis was induced by intravenous injection of the specific antigen in eight ovalbumin‐sensitized monkeys. Changes in respiratory mechanics, acid‐base status and blood gases were studied during the following half hour. Within 1 minute after challenge, a short period of respiratory depression, probably reflex‐mediated, was observed. This was followed by hyperventilation, and arterial Pco2 decreased. There was a rapid increase in pulmonary resistance (Rpulm) and a concomitant decrease in pulmonary dynamic compliance (Cdyn), suggesting constriction of smooth muscles in the lung. Rpulm returned to the control value but Cdyn remained depressed, as a result of constriction of small airways and pulmonary congestion. Oxygen saturation in arterial blood decreased slightly due to a marked destruction of mixed venous blood and increased venous admixture. Progressive metabolic acidosis developed, indicating poor tissue oxygenation and perfusion. The changes observed in this study were not severe enough to cause any major disturbance of the gas exchange in the lungs, despite a severe anaphylactic shock.
Studies on Intrapulmonary Gas Distribution in the Normal Subject Influence of Anaesthesia and Artificial Ventilation
Authors: Hedenstierna G. , Santesson J.
Published: January 2009

Intrapulmonary gas distribution, assessed by a multiple breath, nitrogen washout technique and expressed by the Fowler index NWOD, was studied in subjects with healthy lungs during spontaneous breathing while awake, and during mechanical ventilation under halothane anaesthesia. The distribution index rose from a mean of 32% awake to 56% during anaesthesia. An attempt was also made to differentiate between the contribution of gravitational (airway closure) and non‐gravitational (diffuse airway obstruction) inhomogeneity of ventilation. This was accomplished by measurement of the slope of the alveolar plateau during a single breath nitrogen washout. The slope was similar awake and anaesthetized, and it increased equally under both conditions, when preinspiratory lung volume was stepped up from RV to CC, CC being the lung volume at which airways begin to close during expiration. NWOD was significantly correlated to the degree of airway closure, expressed as FRC‐CC, and, less so, to inspiratory resistance. It is suggested that a less efficient ventilation distribution in anaesthetized normal subjects, as measured by NWOD, is caused rather by airway closure (gravitational inhomogeneity) than by diffuse airway obstruction (non‐gravitational inhomogeneity of ventilation).
Effect of Segmental Epidural Block on the Course of Labour and the Condition of the Infant during the Neonatal Period
Authors: Willdeck‐Lund G. , Lindmark G. , Nilsson R. A.
Published: January 2009

Epidural block for vaginal delivery was given to 242 women during a 6‐month period. Of these, 178 with a spontaneous start of labour and vaginal delivery were studied with respect to the effect of epidural block with bupivacaine‐adrenaline on the course of labour and the condition of the infant in women with normal uterine activity and women with primary uterine inertia treated with oxytocin infusion. On average, the 178 women had already had a longer course of labour before the block was applied than women in control groups. The block per se bad only a slight effect on the first stage of labour, but the effect on the second stage was more obvious, leading to outlet extraction in 50% of the primiparous women, compared to 12% of the controls. Transitory asphyxia at birth was observed in 4.5% of the infants of mothers with epidural block, but after 5 min, only 1% had an Apgar score of less than 7. Infants of mothers with epidural block were more often placed under observation or treated in the neonatal ward than infants in control groups.
Circulatory Pattern and Duration of Action of Naloxone in Dogs With and Without Opioid Pretreatment
Authors: Schweichel E. , SChmidt D. , SChneider E. , Brückner J. B.
Published: January 2009

We investigated the circulatory pattern of naloxone reversal after high‐dose fentanyl infusion in dogs. Within 1 min there was a sudden decrease in total peripheral resistance with a concomitant increase in stroke volume index. All other parameters changed back in the direction of prefentanyl values in various degrees with peak effects in about 3–7 min. The persistency of reversal was different for individual parameters, but 20 min after injection of naloxone almost all changes induced by antagonisation of narcotic activity had returned to pre‐naloxone cvels. In a control series with animals not pretreated with opioid, naloxonr was shown to have no specific pharmacologic action of its own.
Effect of Halothane Anaesthesia on Primary Antibody Response in the Chicken
Authors: Salo M. , Viljanen M. , Kangas L. , Lehtonen O.‐P.
Published: January 2009

The effect of a single anaesthesia of 2 hours' duration with 1% v/v halothane and of 1, 2 and 3 hours' duration with 2%, v/v halothane was studied on the primary antibody response in line‐bred chickens. In contradistinction to earlier studies, the immunization was performed during anaesthesia to resemble antigenic exposure in surgical practice. The IgG and IgM antibodies against the antigens, bovine serum albumin (BSA) and formalin‐killed Brucella abortus organisms (Brucella), were quantified by the enzyme‐linked immunosorbent assay (ELISA). The halothane concentration of the blood was measured by gas chromatography at the end of anaesthesia.

Anaesthesia with 1% and 2%, v/v halothane given in the antigen‐processing phase of humoral immune response had no effect on the concentrations of IgG‐and IgM‐anti‐USA and IgG‐ and IgM‐anti‐Brucella antibodies in the primary antibody response.
Influence of Ventilatory Frequencies and Ventilator Volume/Pressure Quotients on Pulmonary Ventilation Using a Tidal Volume Ventilator
Authors: Lindahl S. , Arborelius M. , Okmian L.
Published: January 2009

The influence of ventilatory frequency and the ventilator's “internal state of gas compression” (Cvent) on mechanics of ventilation, pulmonary ventilation, gas distribution, gas exchange and lung perfusion was studied with free airway and experimental regional airway obstruction in 10 piglets (7–12 kg b.w.), using a tidal volume ventilator. The VDphys/VTexpratio was greater at f = 30 than at f = 10.3 cycles/min. This could be related to a significant increase in the VDanat/VTexpratio at f = 30, while VDc/VTexpand VDlav/VTexpwere unchanged at both frequencies. With regional bronchial obstruction and f = 30, the regional ventilation and perfusion within the obstructed pulmonary field were reduced, compared to the values at f = 10.3 cycles/min. With Cvent20 ml/kPa, the tidal volumes were insufflated in a shorter time and with a higher initial tracheal peak pressure than with Cvent80 ml/kPa. Following bronchial obstruction, VA, RQ and Pao2were greater with Cvent20 than with Cvent80 ml/kPa. With Cvent20, the ventilation of the lung bases was reduced, which was compensated for by a large increase in ventilation within the apical areas of the lungs, while gas distribution within the unobstructed areas was more evenly distributed with Cvent80. Ventilation at Cvent20 showed no essential advantage over Cvent80. Only in lungs extremely difficult to ventilate and with ventilatory frequencies over 50 cycles/min could possible indications for Cvent20 be seen.
Sodium Nitroprusside as a Hypotensive Agent in Intracranial Aneurysm Surgery
Authors: Rudehill A. , Gordon E. , Lagerkranser M.
Published: January 2009

Sodium nitroprusside (SNP) was used to induce hypotension during intracranial aneurysm surgery in 67 patients. The effects of SNP infusion (0.1 mg/ml) on blood pressure were rapid and it was easy to adjust blood pressure to desired levels in most patients. When SNP was stopped, the blood pressure returned instantly to the initial level. In eight patients an increase to about 25% or more above prehypotensive level was seen, counteracted in two patients by administration of small doses of halothane. There was a mean increase of 36% in heart rate. Total doses of SNP were 0.05–120 mg (mean: 10.8), corresponding to 0.08–6.8 μg/kg/min (mean: 1.9). No metabolic acidosis indicating cyanide intoxication was observed. Tachyphylaxis was seen in three patients, and SNP had to be discontinued in one. It is concluded that SNP gives a rapid and effective hypotension but tachyphylaxis and subsequent danger of cyanide intoxication exist. Therefore, in some cases SNP has to be replaced by or combined with some other hypotensive agent to achieve the desired effect. As there is a risk of impairment of cerebral autoregulation after the use of SNP, it is important to avoid sudden and prolonged blood pressure fluctuations, and to continue with controlled hyperventilation in the postoperative period to reduce the risk of brain oedema and high intracranial pressure.
Prediction of Postoperative Hypoxemia in Smokers and Non‐smokers
Authors: Holtz B. , Bake B. , Sixt R.
Published: January 2009

Age, weight, spirometric variables, peak expiratory flow and airway closure assessments were rorrelated to postoperative gas exchange in 40 cholecystectomized subjects grouped according to smoking history. Pao2was significantly lower in the smoking group both pre‐ and postoperatively, but the decrease in Pao2following operation was of the same magnitude irrespective of smoking history. In non‐smokers, the preoperative relationship between expiratory reserve volume and closing volume (ERV‐CV) showed the highest correlation to postoperative alveolar‐arterial oxygen difference P(A‐a)o2(r = ‐0.88,P<0.001) and to the increase of P(A‐a)o2following operation (r = ‐0.67,P<0.001), whereas age was found to be the best preoperative predictor of postoperative gas exchange in smokers.
Patient Controlled Analgesic Therapy in the Early Postoperative Period
Authors: Tamsen A. , Hartvig P. , Dahlström B. , Lindström B. , Holmdahl M. Hson
Published: January 2009

Fourteen patients with postoperative pain were allowed to self‐administer preset doses of pethidine intravenously via a logic‐controlled motor syringe. Plasma samples were collected during anaesthesia and the postoperative self‐administration period, and the concentrations of pethidine and nor‐pethidine were determined. Separate single‐dose studies in eight patients yielded pharmacokinetic parameters which made possible computer simulations of continuous plasma concentration curves for the anaesthesia and postoperative self‐administration period. The consumption of pethidine showed great interindividual variations with a mean consumption for the entire group of 26 mg per hour. The patients established steady‐state plasma concentrations with far less than the maximum amount of pethidine allowed. The mean measured plasma concentration of pethidine which provided adequate analgesia was 738 ± 149 ng/ml. Simulated and measured plasma concentrations were in close agreement. The individual mean drug consumption per hour during self‐administration correlated closely with the individual elimination rate of pethidine. No serious side effects were observed. Thus, patient‐controlled analgesic therapy offers an individualized analgesic supply to meet an analgesic demand which is governed by each patient's appreciation of pain.
Cardiovascular Effects of Neurolept Anaesthesia in Patients with Coronary Artery Disease
Authors: Tydén H. , Westerholm C. J.
Published: January 2009

An anaesthetic technique comprising a combination of phenoperidine (0.1 mg kg‐ l), diazepam (0.06 mg kg ‐ l) and pancuronium bromide (0.1 mg kg‐1) with controlled ventilation was evaluated in 12 patients with severe coronary artery disease. The heart rate, cardiac output and mean arterial blood pressure did not change significantly between the preinduction and postinduction measurements. The right atrial pressure and pulmonary capillary wedge pressure decreased significantly by 33% and 36%, respectively, probably due to the influence of positive‐pressure ventilation. There was no depression of the left ventricular performance.
Myocardial Performance Early After Aorto‐Coronary Bypass Surgery and the Influence of Nitroprusside Infusion
Authors: Tydén H. , Johansson L. , Nyström S.‐O. , Westerholm C. J.
Published: January 2009

The central and peripheral circulation were studied in 12 patients after aorto‐coronary bypass surgery. During the initial 5 h after termination of cardiopulmonary bypass, the oesophageal temperature rose from 36.5°C to 39.4°C, concomitant with cutaneous vasoconstriction and an increase in systemic vascular resistance (SVR) and mean arterial blood pressure (MABP). The oxygen uptake index (Vo21) increased by 57% during the rewarming period. The cardiac index (CI), which was constant at 2.8 1 min‐1 m‐2, was too low to satisfy this oxygen demand and the arterio‐venous oxygen content difference (AVDo2) increased to 3.0 mmol 1‐‐1 by the 3rd hour. After 5 h, SVR had decreased and cutaneous vasodilation began. Vo2 I and AVDo2 decreased. The postoperative myocardial function was moderately impaired and deteriorated after the cutaneous vasodilation. Twelve patients were given an infusion of sodium nitroprusside during the postoperative period (0.25–2.5 μg. kg‐1 min‐1). The rewarming pattern was not influenced by this inrusion, but the initial increases in MABP and SVR were eliminated. The myocardial performance was better in the nitroprusside group. CI was significantly higher than in the control group (3.5 1 min‐1 m‐2) and AVDo2 remained normal.
Embryotoxicity and Fertility Study with Halothane Subanesthetic Concentration in Rats
Authors: Popova S. , Virgieva T. , Atanasova J. , Atanasov A. , Sahatchiev B.
Published: January 2009

The effect of 9 ppm halothane, a subanesthetic concentration, was studied on the reproductive ability and pregnancy outcome in white rats. Pregnant females were exposed for 4 h per day during the whole gestation period. Male animals were subjected to halothane inhalation for 4 h daily, 5 days per week for 6 or 8 months. In the exposed females higher rates were established for early interruption of pregnancy (all implants dead) and for embryonic death in the later periods of intrauterine life compared to controls. Deciduomata were found in 22.22% (P<0.05) of pregnant treated females. Control females mated to exposed males showed a higher incidence of preimplantation loss (36.36% (P<0.05) of those mated with males exposed for 6 months had deciduomata). Decreased fertility in males, expressed particularly in the 8‐month treated group, was also demonstrated (13.33% inseminated females, compared to 35% in the control group).
Changes in Placental Intervillous Blood Flow Measured by the 133Xenon Method During Lumbar Epidural Block for Elective Caesarean Section
Authors: Huovinen K. , Lehtovirta P. , Forss M. , Kivalo I. , Teramo K.
Published: January 2009

The effect of lumbar epidural block on placental intervillous blood flow (IBF) was estimated with the i.v. 133Xe method in 24 cases and in 14 controls. All parturients had uneventful pregnancies and were scheduled for elective caesarean section. Lumbar epidural block caused a significant decrease in maternal mean arterial pressure (MAP), when no preloading infusion with a plasma expander was given. In contrast, the MAP remained unchanged during lumbar epidural block when the parturients received a preloading infusion (Haemaccel®, 100 m1/10 kg body weight within 10 min immediately before lumbar epidural block). The IBF decreased to some extent in the non‐preloaded group, but increased temporarily in the preloaded group 15 min after the administration of lumbar epidural block. The mean changes of IBF in the non‐preloaded and the preloaded group? differed statistically significantly from each other during lumbar epidural block. The IBF of the preloaded group did not differ significantly from the IBF of the control group receiving no lumbar epidural block.
Transcutaneous Oxygen Measurement in Adult Intensive Care
Authors: Löfgren O.
Published: January 2009

Transcutaneous oxygen measurement (Ptco2 ‐measurement) gives by a non‐invasive technique continuous information about central Po2 The method has as yet been tested mainly on newborns, and systematic studies of the applicability of the method on adults are still few. The current systematic study reports on consecutive Ptco2 measurements in 15 patients, all with indwelling arterial cathelers: 13 of the patients were artificially ventilated; 5 patients had normal body structure and normal skin circulation; 5 patients were obese and had normal skin circulation; and 5 patients were hypothermic with a normal heart frequency or slight bradycardia.

The Radiometer equipment TCM1 was used. The electrode surface temperature was 45.0°C (within ±0.2°C). The oxygen concentration in the inspired air was altered several times for all patients, and arterial samples were drawn at a stable Ptco2 level. On average, seven samples were drawn from each patient.

The correlation between Ptco2 and Pao2 was highly significant in 4/5 patients, in both the “obese patient” group and the “normal patient” group. In the “hypo‐thermic patient” group, the correlation between Ptco2 and Pao2 was highly statistically significant in 2/5 patients. The regression line between Ptco2 and Pao2 was calculated for each patient, and a mean regression line was obtained for each group. It was found that the regression line in the “obese patient” group was displaced to the right and parallel to the regression line in the “normal patient” group, while the regression line in the “hypothermic patient” group was less sloping and showed a higher intercept.

The Ptco2 monitoring technique reliably reflects changes in the central oxygenation of adult intensive care patients. In some patients with decreased skin circulation, the relationship between Ptco2 and Pao2 seemed to be constant for the same patient, yielding statistically significant correlations. However, the study cannot determine whether this would be true in all clinical situations; the relationship between Ptco2 and Pao2 should therefore be checked frequently when measurements are performed in patients with decreased skin circulation. The author's experience with the Ptco2 monitoring method in patients near death has been consistent with the obvious fact that the reliability of the method decreases with decreased skin circulation.