bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Incremental Halothane Levels on the Reflex Responses to Carotid Hypotension in the Dog
Authors: Bagshaw R. J. , Cox R. H.
Published: January 2009

Arterial baroreceptor function was assessed in trained, chronically instrumented dogs by measuring the systemic haemodynamic responses to brachiocephalic artery occlusion (BCO). BCO was carried out in awake dogs and repeated at end‐tidal halothane levels of 0.75 ± 0.01 % (H1), 0.94 ± 0.02% (H2) and 1.13±0.02% (H3). Before BCO, at H1 only the increased heart rate and decreased stroke volume were significantly different from awake controls (P<0.01). Mean arterial pressure and cardiac output at H2 and H3 were significantly lower than in the awake controls (P<0.05). The pressor response to BCO fell progressively with increasing halothane levels, the decrease being significant at the H2 and H3 levels (P<0.001). There was a good linear correlation between the pressor response to BCO as a percentage of the response in awake animals, and the end‐tidal halothane levels (r= ‐0.816, P<0.001). This indicated a sensitive dose‐dependent modification of the haemodynamic response to BCO by halothane. However, halothane levels existed between about 0.7‐0.8%, at which levels the average pressor response to BCO was not significantly different from awake values.
Splanchnic Turn‐over of Some Energy Metabolites and Acid‐Base Balance during Intravenous Infusion of Lidocaine, Bupivacaine or Etidocaine
Authors: Wiklund L. , Jorfeldt L.
Published: January 2009

The splanchnic turn‐over of energy metabolites in circulating blood has been studied in four groups of young, healthy volunteers, receiving intravenous infusions of physiological saline (n = 5), lidocaine 4 mg/min (n = 7), bupivacaine 2 mg/min (n = 7) and etidocaine 2 mg/min (n = 8). The results showed that the local anaesthetic agents increased the splanchnic blood flow and oxygen consumption, the uptake of glycerol and lactate, and the release of 3‐hydroxybutyrate. These effects are adrenaline‐like but cannot be explained by one single mechanism involving increased activity of the sympathetic nervous system. Only a minor part of the increased oxygen uptake could be attributed to the energy cost of drug metabolism.
Paracetamol, Tiaramide and Placebo for Pain Relief after Orthopedic Surgery
Authors: Winnem B. , Samstad B. , Breivik H.
Published: January 2009

Eighty patients took part in this double‐blind, single‐dose group‐comparative study, comparing the analgesic efficacy of tiaramide hydrochloride 100 mg and 200 mg, paracetamol 1000 mg, and placebo for pain after orthopedic operations. The four treatment groups were similar on entry to the trial. Pain relief was assessed up to 6 h after treatment, using a visual analogue pain scale and a pain score, both giving similar results. Statistically significant pain relief (mean pain intensity differences and sum of pain intensity differences) was seen in the group receiving paracetamol compared to those receiving placebo or tiaramide from 1 h to 6 h after drug ingestion. There was no significant difference between placebo and tiaramide 100 or 200 mg. No adverse reactions were reported.
Human Body Temperature and Controlled Cold Exposure during Moderate and Severe Experimental Alcohol‐Intoxication
Authors: Risbo A. , Hagelsten J. O. , Jessen K.
Published: January 2009

In an attempt to obtain more conclusive data, especially concerning the condition in cases of very high alcohol concentration, two groups of healthy volunteers were exposed to controlled cold surroundings in a climate chamber after i.v. infusion of 96% ethyl alcohol, l‐21/2 ml per kg bodyweight, supplemented with alcohol perorally; the maximum blood alcohol concentration measured was 57 mmol/1, corresponding to 2.62%***. One group was not habituated to drinking; the other group was habituated to heavy drinking, but functioned well socially. During the stay in a neutral environment, the alcohol infusion caused a rapid elevation of skin temperature with a short, but significant delay in temperature elevation in the alcohol‐habituated group. After controlled exposure to cold, a rapid fall in surface temperature back to pre‐alcoholic infusion values was seen in both groups. During cold exposure, core temperature remained unchanged in both groups. No changes in plasma catecholamines were found. A 12–18% increase in metabolic rate was seen in both groups during cold exposure, probably as an expression of the specific dynamic effect of alcohol. That the observed vasoconstriction was sufficient to prevent an undue fall in core temperature is further supported by the fact that neither shivering, nor non‐shivering thermogenesis was activated, as no visible shivering occurred and no rise in plasma catecholamines was seen.
Org NC 45 and Intraocular Pressure During Anesthesia
Authors: Sia R. L. , Rashkovsky O. M.
Published: January 2009

The effects on intraocular pressure (IOP) of Org NC 45, an analogue of pancuronium with a rapid onset of action and fast recovery, were evaluated in 15 ASA class I and II patients undergoing elective eye surgery. IOP fell by 21 % after induction with thiopentone and rose only slightly after administration of NC45, 0.1 mg/kg and intubation. However, in the 5‐min period following intubation, during which the patients received only nitrous oxide in oxygen, prior to administration of halothane and fentanyl, IOP was still significantly less than during the pre‐induction control period.
Influence of Abdominal Surgical Trauma on Substrate Utilization by the Human Brain
Authors: Stjernstrom H. , Jorfeldt L. , Wiklund L.
Published: January 2009

In 10 patients undergoing cholecystectomy, measurements of jugular venous blood flow (one side) and arterio‐jugular vein differences of oxygen, glucose, lactate, pyruvate, glycerol, 3‐hydroxybutyrate and alanine were made. The arterial concentration of 3‐hydroxybutyrate was raised during surgery, but this substrate only covered a minute part of the total energy demand. The need for substrates of oxidative metabolism in the brain was met by glucose. During the operation the stoichiometrically calculated oxygen uptake was lower than that of glucose, indicating an increase in the brain glucose content.
Blood Concentration of Lidocaine after Spinal Anaesthesia Using Lidocaine and Lidocaine with Adrenaline
Authors: Axelsson K. , Widman B.
Published: January 2009

In 32 patients undergoing spinal anaesthesia with lidocaine or lidocaine plus adrenaline, the concentration of lidocaine base was measured in repeated venous blood samples. Half of the patients were given 100 mg lidocaine alone and the other half 100 mg lidocaine with the addition of 0.2 mg adrenaline. The blood concentration of lidocaine was significantly higher in the lidocaine group than in the group that received lidocaine with adrenaline. The mean maximal concentrations in these two groups lay between 0.2 and 0.3 and between 0.1 and 0.2 μg/ml, respectively (P<0.01). The time required for the individual maximal concentration to be reached was independent of whether the anaesthetic contained adrenaline or not. The blood concentration showed no correlation to body weight, height, or body surface area. In the first 60 min after the spinal injection the extent of the sensory block was the same in the two groups, but at 120 min this extent was significantly greater in the lidocaine‐adrenaline group (P<0.01). The results show that the blood concentration of iidocaine is low in spinal anaesthesia compared with other types of regional anaesthesia.
Respiratory, Analgesic and Endocrine Responses to an Enkephalin Analogue in Normal Man
Authors: Lindeburg T. , Larsen V. , Kehlet H. , Jacobsen E.
Published: January 2009

In a controlled study, the effect of a new enkephalin analogue (FW 34–569, Sandoz) on respiratory function (ventilatory response to CO2), pain threshold (hot plate technique), and plasma cortisol, prolactin, growth hormone, luteinizing hormone (LH) and follicle‐stimulating hormone (FSH) was investigated in six normal subjects. One milligram of enkephalin, but not 0.5 mg, resulted in a significantly decreased ventilatory response to CO2, although mean values were not significantly different from saline control values (0.05 < P< 0.1). Neither 0.5 mg nor 1.0 mg enkephalin influenced pain threshold, but both doses stimulated growth hormone and prolactin release and inhibited the release of cortisol and LH, while FSH remained unchanged.
Effects of Renal Function on Serum Fluoride Level in Dogs During and After Enflurane Anesthesia
Authors: Wickström I. , Stefansson T. , Sundström E.
Published: January 2009

To study the effect of renal function on the increased serum inorganic fluoride level produced by the metabolism of enflurane, three groups of beagle dogs were exposed to prolonged enflurane anesthesia, 1.25 MAC for 8 h. One group was studied both with and without renal function, one group only without renal function, and one group on two different occasions with renal function intact. Serum inorganic fluoride levels were determined every hour during the enflurane anesthesia and on termination for a further 4 h. In dogs with no renal function, the increase rate and the peak of serum inorganic fluoride level were significantly higher than in dogs with renal function. The average peak level in dogs with renal function was 21.4 μmol/1 and in dogs with no renal function 38.4 μmol/1.

Renal function was found to have the same capacity to increase the inorganic fluoride elimination from serum as other routes of elimination. At corresponding serum levels, the rate of decrease after terminating enflurane anesthesia was 3.5–4.0 μmol/1/h lower without renal function. Reanesthesia after 3 weeks did not significantly change the serum inorganic fluoride levels compared to the first anesthesia.
Lumbar Epidural Anaesthesia With Bupivacaine in Old Patients: Effect of Speed and Direction of Injection
Authors: Rosenberg P. H. , Saramies L. , Alila A.
Published: January 2009

The spread of lumbar epidural analgesia was studied in 48 old urological patients (56–81 years). Bupivacaine 0.5% 20 ml was injected at either 1 ml/s with a Tuohy needle with the bevel directed cephalad (Group I) or caudad (II) and at 0.22 ml/s directed cephalad (III) or caudad (IV). Immediately after injection, the patients moved from a sitting to a horizontal position and analgesia was tested every 2 min by skin pin‐prick. At 10 min, there were differences in the mean caudad spread; the greatest spread in Group II was 4.5 segments and the smallest in Group III 2.4 segments, not significant (n.s.). The differences became smaller with time and the maximal spread after 30 min was similar in all groups. In six patients, who all belonged to either Group I or Group III (bevel cephalad), skin analgesia did not reach the S 5 segment. One of the Group I patients developed a transient motor paralysis of the lower extremities immediately upon injection. All patients recovered completely from the block and no toxic reactions were observed. The duration of the block and the accompanying fall of blood pressure were similar in the different groups. The mean venous blood levels of bupivacaine were highest in Group III and lowest in Group I (n.s.). The highest individual bupivacaine blood level was 1.25 μg/ml 30 min after injection, while generally the highest concentrations appeared at 20 min after injection. The study indicated a lack of significant difference on varying the speed of injection or turning the Tuohy needle, but it has to be emphasized that this may apply only to bupivacaine, which has distinct physicochemical properties, and also to old patients with an age‐dependently modified epidural space.
Myocardial Oxygen Consumption and Coronary Haemodynamics during Fentanyl‐Droperidol‐Nitrous Oxide Anaesthesia in Patients with Ischaemic Heart Disease
Authors: Reiz S. , Bålfors E. , Häggmark S. , Nath S. , Rydvall A. , Truedsson H.
Published: January 2009

Eight patients with stable ischaemic heart disease were investigated to determine the effects of fentanyl (15 μg/kg) ‐ droperidol (150 μg/kg) ‐ nitrous oxide (75%) anaesthesia, without concomitant fluid challenge, on myocardial oxygen consumption and lactate uptake, and central and coronary haemodynamics. Anaesthesia induced reductions in mean arterial pressure (— 35%, P<0.01), systemic vascular resistance (— 30%, P<0.01), left ventricular stroke work index (—50%, P<0.01) and total body oxygen consumption (— 23%, P<0.01), with no changes in heart rate, cardiac output or mean pulmonary arteriolar occlusion pressure. Mixed venous oxygen content increased (P< 0.05). Systemic vasodilatation, circulatory adaptation to an overall lower metabolic rate, and clinically negligible cardiodepression are the likely mechanisms behind the central haemodynamic response to this form of anaesthesia. Coronary sinus blood flow (measured by the continuous thermodilution technique) decreased (P<0.01) in parallel with the decrease in coronary perfusion pressure. Thus coronary vascular resistance remained unchanged. As expected from the haemodynamic findings, myocardial oxygen consumption decreased (—37%, P<0.01). Coronary sinus oxygen content and myocardial oxygen extraction did not change, nor was myocardial lactate uptake affected. No ST‐T‐segment depressions or dysrhythmias were recorded. These observations indicate that myocardial oxygenation was adequate in spite of the reduction in coronary perfusion pressure. There was poor correlation between changes in myocardial oxygen consumption and rate pressure product (R=0.455) or triple product (R=0.375).
Effects of Fentanyl on Respiratory Pressure‐Volume Relationship in Supine Anesthetized Children
Authors: Marty J. , Desmonts J. M.
Published: January 2009

The effects of fentanyl on total respiratory pressure‐volume relationship were studied in 12 supine, anesthetized (thiopental, succinylcholine, halothane, N2O/O2) children, 5, 10 and 15 min after administration of fentanyl, 3 μg/kg (Group F) and at similar intervals in 11 control, anesthetized children who did not receive fentanyl (Group C). Lung and chest wall pressure‐volume relationships were measured in five children from Group F and in six from Group C. Compliance values were estimated from the linear part of PVR curves. In Group F, a significant decrease was observed at 5, 10 and 15 min (maximum 29%) for total compliance and at 15 min (maximum 26 %) for lung compliance. Chest wall compliance was reduced (maximum 45 %) at 15 min, but not significantly. In Group C., no change in compliances was noted. The comparison between the two groups for total, chest wall and lung compliances showed a significant decrease in these three parameters at 15 min in children receiving fentanyl. The decrease of chest wall compliance can be explained by increased muscle tone, but the mechanism of decreased lung compliance awaits further study.
Distribution of Inspired Gas to Each Lung in Anesthetized Human Subjects
Authors: Bindslev L. , Santesson J. , Hedenstierna G.
Published: January 2009

The distribution of ventilation in man during halothane anesthesia was studied in a two‐compartment lung model in which each lung was ventilated separately by means of a double‐lumen tracheal tube. Eight subjects were studied prior to scheduled surgery. Tidal volume distribution was even between the lungs in the supine position (horizontal distribution) as was distribution of dynamic lung compliance, resistance and dead space. The vertical distribution was assessed when the patient was in the left lateral position. Dependent dynamic lung compliance and dead space were lower and lung resistance was higher than in the non‐dependent lung. These factors favoured a non‐dependent lung ventilation and, moreover, caused a re‐distribution from dependent to non‐dependent lung during an end‐inspiratory pause (EIP), thus increasing the inhomogeneity of ventilation. The application of a positive end‐expiratory pressure (PEEP) of 10 cmH2O improved dependent ventilation and abolished redistribution between the lungs. In conclusion, uneven distribution of dynamic lung compliance and lung resistance causes inhomogeneous ventilation distribution, favouring the non‐dependent lung. An EIP enhances and a PEEP reduces the inhomogeneity of ventilation.
Humidity and Temperature Changes during Low Flow and Closed System Anaesthesia
Authors: Aldrete J. A. , Cubillos P. , Sherrill D.
Published: January 2009

Water humidity and temperature were measured in the proximal end of the inspiratory limb in anaesthetic circuits used to anaesthetize three groups of adult patients using various fresh gas flows (FGF). Humidity increased as FGF's were lowered, with 98% water humidification achieved when FGF's of less than 0.5 1/min were administered. Temperature at the same site changed about 1–2.5d̀C in inverse proportion to the volume of FGF. This advantage of closed system and low flow anaesthesia is a further reason for their wide‐spread utilization.
Thermocamera Studies of Enflurane and Halothane Vapours
Authors: Carlsson P. , Ljungqvist B. , Allander C. , Hallen B. , Norlander O.
Published: January 2009

The ability of enflurane and halothane to absorb infra‐red (IR) energy was used to visualize their vapours; IR radiation was emitted by a heated screen and the absorption was studied with an IR camera. Even small concentrations of enflurane (0.2 vol%) and halothane (0.5 vol%) could be detected when released into the operating room atmosphere. Enflurane and nitrous oxide were dispersed in a similar way when they leaked from the face mask. Thus when anaesthetic pollution is monitored in the operating room, measurements of the concentration of nitrous oxide are sufficient for routine purposes. The IR method has added a new dimension to the study of occupational exposure to otherwise invisible gases.
Pentoxifylline does not Change Cerebral Blood Flow or Metabolism in the Dog
Authors: Steen P. A. , Milde J. H. , Michenfelder J. D.
Published: January 2009

Pentoxifylline 0.3–30 mg/kg was given intravenously to six dogs under nitrous oxide anesthesia. Cerebral blood flow was measured with a sagittal sinus outflow technique, cerebral oxygen consumption was calculated from the a‐v difference, and metabolite levels were determined in biopsies of cerebral cortex. Pentoxifylline failed to influence cerebral blood flow or oxygen consumption. There was no increase in cerebral levels of phosphocreatine, ATP or total adenine nucleotides; the only significant effect was higher glucose levels in dogs given pentoxifylline (4.49±0.39μmol/g vs 2.21 ±0.18 μmol/g). The latter has previously been reported to be deleterious during cerebral ischemia. Pentoxifylline thus failed to have any significant influence upon cerebral blood flow or metabolism in the dog likely to be of benefit during cerebral hypoxia or ischemia.
Dopamine Infusion in Man. Plasma Catecholamine Levels and Pharmacokinetics
Authors: Järnberg P. O. , Bengtsson L. , Ekstrand J. , Hamberger B.
Published: January 2009

Dopamine is widely used in the treatment of hypotensive conditions and/or impending renal failure, but the plasma levels of dopamine and other catecholamines in association with dopamine infusion are not known. Plasma catecholamines and dopamine pharmacokinetics during and after dopamine infusion were therefore studied in man. Two and 5 μg ‐ kg‐1 ‐ min‐1 of dopamine were infused for 30 min in two groups of five patients. Dose‐dependent mean steady state levels with fairly large interindividual variations were reached within 5 min. Elimination of dopamine from plasma after termination of infusion had a biphasic course with t 1/2 around 1 min and t 1/2 β about 9 min in both groups. Noradrenaline plasma levels and blood pressure increased significantly in the 5 μg group. It is suggested that the vasoconstriction with deleterious effects on tissue perfusion, seen in conjunction with high‐dose dopamine infusion, may be due to increased noradrenaline levels.
Hemodynamic Consequences of Defence Area Stimulation and Afferent Somatic Nerve Stimulation During Fentanyl‐Nitrous Oxide Anesthesia. Modifying Effects of Droperidol
Authors: Biber B. , Martner J.
Published: January 2009

Stimulation of the hypothalamic defence area and activation of somatic afferents in combination with carotid baroreceptor unloading was performed in cats anesthetized with fentanyl‐nitrous oxide in order to investigate the circulatory consequences in terms of regional blood flow changes. These stimulation procedures, suggested to mimic activation of central neurogenic cardiovascular control mechanisms caused by anesthesia and surgical stress, were found to induce pronounced reductions in intestinal and renal blood flow as well as in diuresis. However, administration of droperidol markedly diminished the renal vasoconstriction as well as the reduction in diuresis in the dose range 0.025–0.10 mg/kg b.w. Doses of 0.15–0.25 mg/kg b.w. virtually abolished any stimulation‐induced increase in renal vascular resistance, whether elicited through activation of the defence area or somatic afferents. This dose also partly blocked the neurogenic increment of intestinal vascular resistance.
Activation of the Supraspinal Pain Inhibition System by Ketamine Hydrochloride
Authors: Tomemori N. , Komatsu T. , Shingu K. , Urabe N. , Seo N. , Mori K.
Published: January 2009

The neurophysiologic mechanism of ketamine‐induced analgesia was studied in cats under conditions of electrolytic decerebration or pentobarbital anesthesia. Injection of bradykinin into the femoral artery served as the noxious stimulus and the neural response in the lateral funiculus of the spinal cord was recorded by the multi‐unit activity technique. Ketamine depressed the bradykinin‐induced response more markedly in decerebrate, non‐anesthetized cats than in pentobarbital‐anesthetized cats. The depressant action disappeared following cervical cord transection at C1, in both decerebrate non‐anesthetized and pentobarbital‐anesthetized cats. Thus, the analgesic action of ketamine is probably exerted mainly through activation of the supraspinal pain inhibition system and a direct action on the spinal cord nociceptive neural mechanism, if any, is slight. The excitatory action of ketamine on the supraspinal pain inhibition system is susceptible to the depressant action of pentobarbital.
Central Haemodynamics, Oxygen Transport and Oxygen Consumption During Three Methods for CPAP
Authors: Vuori A.
Published: January 2009

During the weaning period after 18 hours of mechanical ventilation following open heart surgery, central haemodynamics, systemic oxygen transport and total oxygen consumption were assessed in a total of 17 patients, receiving continuous positive airway pressure (CPAP) therapy. Three different means of providing CPAP were studied: an electronically controlled method (mode S); a method based on the Venturi principle along with a continuous flow of gases via the T‐piece connector attached to the intubation tube (mode B); and a method employing an elastic inspiratory gas reservoir (mode C). The inspiratory pressure plateau was adjusted to be equal under the different methods for CPAP. The airway pressure range, the expiratory and mean airway pressures and the mean oesophageal pressure were seen to be highest during mode S. The pulmonary vascular resistance was higher during mode S than during modes B and C, and the mean pulmonary arterial pressure was higher during mode S than mode C. While the cardiac index remained statistically unchanged under the three methods for CPAP, the stroke index (SI) and the left ventricular stroke work index (LVSWI) were higher during mode C than mode S. As the transmural right atrial and pulmonary capillary wedge pressures were unchanged, these alterations in SI and LVSWI might be a consequence of airway pressure‐induced changes on the myocardial performance. Arterial oxygenation was good and unchanged during the study; mixed venous oxygen tension (Pvo2) was higher and the arteriovenous oxygen content difference (avDo2) was smaller during mode B than during mode C. During mode S, the total oxygen consumption was higher than during mode B. On the basis of the observations made, there seem to be no major differences in the effects of the three methods for CPAP on the parameters studied. The Venturi principle, employing a continuous flow of gases seems, however, to produce a slightly lower oxygen consumption, while the myocardial performance was best preserved with the system based on the elastic inspiratory gas reservoir.
Patients' Expectations and Acceptance of the Effects of the Drugs Given Before Anaesthesia: Comparison of Light and Amnesic Premedication
Authors: Korttila K. , Aromaa U. , Tammisto T.
Published: January 2009

Patients (130) scheduled for elective general surgery under balanced general anaesthesia were interviewed on the day before operation and asked whether they wanted a light premedication allowing them to remember all events before and after surgery or whether they wanted a potent premedication rendering them amnesic for the events before and after operation. Regardless of their preferences, the patients were given 1 mg/kgofpethidine; 12.5 to 50 mg of promethazine, plus 0.14 mg/kg oxycodone; or 0.05 mg/kg of lorazepam; and 0.01 mg/kg of atropine intramuscularly in random fashion as preanaesthetic medication before operation. On the first postoperative day, patients were questioned again about their opinions of the premedication. Most patients wanted light (53%) or moderate (22%) premedication, and only 5% wanted to receive amnesic premedication. Assessments of degree of fatigue and apprehension were similar after each premedication when assessed before operation. Sixty‐seven and 60% of the patients receiving lorazepam did not remember insertion of the i.v. needle before induction of anaesthesia or the stay in the recovery room, respectively (P<0.01 vs. other groups), whereas most of the patients given pethidine or oxycodone recalled the events before and after operation. Almost all the patients who both expected and received a light (91% acceptance) or an amnesic (100% acceptance) premedication accepted it. However, only 58% of patients who expected to be given a light but received an amnesic premedication were satisfied with it, whereas 89% of patients who expected an amnesic but received a light premedication accepted it. It is concluded that patients' opinions on the potency and capacity of preanaesthetic medication to produce amnesic action should be taken into account in routine clinical work. Administration of a potent, amnesic premedication is indicated only if patients prefer it to light premedication.
Comparison of Physostigmine and Neostigmine for Antagonism of Neuromuscular Block
Authors: Salmenperä M. , Nilsson E.
Published: January 2009

The ability of physostigmine alone and in combination with neostigmine to reverse d‐tubocurarine‐induced neuromuscular block was evaluated in surgical patients. The relaxation was maintained at a level of90 % twitch suppression during balanced anaesthesia, and antagonism was attempted with physostigmine 1.5 mgX3; neostigmine 0.5 mgX3; neostigmine 1.0 mgX3; or with a combination of physostigmine 0.75 mg and neostigmine 0.5 mg × 3.

The measured parameters included the twitch force or EMG amplitude of the adductor pollicis brevis muscle after supramaximal 0.1 Hz stimulation and fading of these responses after repetitive 2 and 50 Hz stimuli. Although the restitution rate of twitch height and EMG amplitude were essentially the same with both antagonists, there was a considerable time‐lag in regeneration of the fades after repetitive stimuli with physostigmine as compared with the neostigmine group. The addition of physostigmine to a subeffective dose of neostigmine resulted in antagonism comparable to that seen in other groups. The clinical antagonism was satisfactory in all patients receiving physostigmine. The divergence of relaxation‐indicating parameters (twitch responses and fades) after physostigmine suggests dissimilar modes of action of the two antagonists at the neuromuscular junction.
Hemodynamics Following Normovolemic Hemodilution in Elderly Patients
Authors: Rosberg B. , Wulff K.
Published: January 2009

The hemodynamic effects of acute hemodilution with dextran 70 as dilutional agent were evaluated in a group of elderly patients (mean age 68, range 60–79 years) anesthetized with neurolept analgesia. The isovolemic exchange of 1.1 liter of blood (mean) with a 6% solution of dextran 70 decreased the hematocrit value from 41 to 28%. As cardiac index did not change, the oxygen transport capacity was significantly reduced. The main compensating mechanism for this was an increased extraction of oxygen in the tissues and, to a minor extent, a raised arterial oxygen tension. The results of this study suggest that intentional hemodilution should be used with caution in aged patients.
Baroreceptor Control of Systemic Haemodynamics at Incremental Halothane Levels in the Dog
Authors: Bagshaw R. J. , Cox R. H.
Published: January 2009

The open‐loop carotid sinus reflex control of systemic haemodynamics was studied in an acute dog preparation with isolated perfused carotid sinuses at three end‐tidal halothane levels of 0.66±0.02% (HI); 0.88±0.02% (H2); and 1.17 ±0.02% (H3), in order to investigate the dose dependency of the carotid sinus reflex operating characteristics for halothane. Corresponcling to the above halothane levels were reflex operating point pressures (set point pressures) of 104.9±2.9, 103.3±4.1 and 76.0±3.8 mmHg, respectively. Carotid sinus reflex gain decreased significantly with progressively increasing halothane levels (1.41 ±0.18; 0.84±0.12; 0.48±0.09), as did the range of reflex changes in systemic arterial pressure for equal overall changes in carotid sinus pressure (87.1 ±7.9; 64.1 ±7.4; 33.6±5.1 mmHg; P<0.01). For halothane levels below approximately 0.9%, this depression was not dependent upon changes in mean systemic arterial pressure. The relationship between reflex gain and halothane concentration could be described by a first‐order exponential which suggested virtual ablation of the carotid sinus reflex control of mean arterial pressure at an end‐tidal halothane concentration exceecling about 1.6%.
Gas Flow Measurements with a Gas Dilution Technique
Authors: Karlmark B. , Ellingsen J. , Englesson S.
Published: January 2009

A new method for gas flow measurements, based on a gas dilution technique, is described. A known amount of fresh room air is injected as a tracer gas into a carrier gas stream. The downstream concentration profile of the tracer gas is recorded with a portable mass‐spectrometer. The flow rate of the carrier gas is calculated from the area under the tracer gas curve as electronically integrated. The method was tested against precision spirometers, one of the rolling seal type and one of the fluidistor type. It was shown that any rapid gas analyser might be used for the analyses, either of the tracer gas or of the carrier gas. The applicability of this method during general Anaesthesia and in other clinical situations is discussed.
Catatonia after Epidural Morphine
Authors: Engquist A. , Jørgensen B. C. , Andersen H. B.
Published: January 2009

A 43‐year‐old male with bronchogenic carcinoma was treated with continuous epidural morphine via a thoracic epidural catheter. On the fifth day, after a total dose of 24 mg morphine chloride in 10 or 20 ml saline, he developed hallucinations, hyperthermia, spasticity, narcolepsy and opisthotonos. Respiratory rate and blood pressure were unaffected. Intravenous naloxone reversed all neurological abnormalities. This unusual syndrome was probably caused by a rostral spread of morphine. The location of the catheter and volume seem to be important variables. Hallucinations are important signs of impencling intoxication.
High‐Dose Analgesic Anesthesia with Morphine or Sufentanil in Propranolol‐Treated Dogs
Authors: Berthelsen P. , Strøm J. , Eriksen J. , Rasmussen J. P.
Published: January 2009

In propranolol‐pretreated dogs (2 mg‐kg‐1) the immediate cardiovascular effects of sufentanil (0.01 mg.kg‐1)or morphine (4 mg.kg‐1) were compared. Besides a 40% decrease in cardiac index (CI), sufentanil and morphine initiated quite different hemodynamic changes. Sufentanil did not significantly change mean arterial pressure (MAP), central venous pressure (CVP) and mean pulmonary artery pressure (MPAP), while the pulmonary capillary wedge pressure (PCWP) increased by 50%. After morphine, MAP declined significantly by about 65 %, and significant decreases in MPAP (14%) and PCWP (33%) were also observed. Propranolol reduced heart rate by 16%, and morphine caused no further reduction in HR. A significant decrease of about 30% was seen in HR after sufentanil. Sufentanil significantly raised systemic vascular resistance index (SVRI) by 15%, whereas morphine decreased it by 32%. Pulmonary vascular resistance index (PVRI) was unchanged after sufentanil, but significantly increased after morphine. Right ventricular stroke work index (RVSWI) was unaffected by both analgesics, and morphine decreased left ventricular stroke work index (LVSWI) significantly by 80%. Oxygen transport index declined significantly after both analgesics. Sufentanii reduced oxygen consumption by 20%, while morphine left this parameter unaffected. We conclude that the administration of high‐dose sufentanil leads to a stable circulation, even when a total β‐blockade exists.
Hepatic Gluconeogenesis During Halothane Anaesthesia in Man
Authors: Andreen M. , Brandt R. , Strandell T. , Vinnars E. , Zetterström B. E. M.
Published: January 2009

It is known that hepatic gluconeogenesis from lactate and aminoacids is inhibited by halothane inin vitrostudies on isolated, perfused livers. In the present work, the effect of halothane anaesthesia on hepatic gluconeogenesis was studied in three volunteers during a constant amino‐acid infusion and compared with three control subjects who did not receive any halothane during the amino‐acid infusion. Prior to the investigation, all the subjects were on a carbohydrate‐poor diet in order to deplete hepatic glucogen stores. During the investigation, hepatic gluconeogenesis was stimulated by a constant amino‐acid infusion which caused a slight rise in total hepatic blood flow (THBF), a marked increase in splanchnic oxygen consumption and oxygen extraction, elevation in blood glucose and urea levels and in splanchnic glucose and urea releases. Halothane anaesthesia administered during continued amino‐acid infusion caused a reduction in THBF to sub‐control values, while the increased oxygen consumption was only slightly reduced, thereby further increasing splanchnic oxygen extraction. Blood glucose and urea levels of the anaesthetized subjects were consistent with those of the control subjects. Splanchnic release of glucose was reduced almost to control values during halothane. However, the release of urea was only slightly reduced. It is concluded that the stimulating effect on hepatic gluconeogenesis caused by the amino‐acid infusion was inhibited during halothane anaesthesia, while metabolization of the amino‐acids, other than through gluconeogenesis, proceeded without any major changes.
Comparison of Thiopentone and Diazepam as Induction Agents of Anaesthesia for Caesarean Section
Authors: Haram K. , Lund T. , Sagen N. , Bøe O. E.
Published: January 2009

Clinical effects of thiopentone (3 mg/kg body weight) and diazepam (0.3 mg/kg) were compared for elective caesarean sections in two groups of 43 and 39 women, respectively. They were given general anaesthesia in left lateral tilt. The systolic, diastolic and mean arterial pressures were moderately elevated at onset of surgery in both groups, probably indicating light anaesthesia. Later, a gradual decrease to the preinduction levels was observed. The mean injection‐delivery (I‐D) interval was 344 s in the thiopentone group and 339 s in the diazepam group. The I‐D intervals were shorter than 10 min in 39 of the cases in the thiopentone group and 38 cases in the diazepam group. Low Apgar scores at 1 min (6 or less) occurred in five of the neonates in each group, while all had normal Apgar scores at 5 min (7 or more). Asjudged by the Apgar scores and the acid‐base status of umbilical cord blood, the effects of the induction agents on the neonatal condition were indistinguishable in the two groups. In the thiopentone group, unpleasant recollections were reported in 5 out of 40 patients (12.5%), compared to none in the diazepam group. Diazepam‐nitrous oxide anaesthesia is well accepted by the mothers and is an alternative to supplementing thiopentone induction with a volatile gas for patients who have previously experienced wakefulness or express fear of awareness. The main drawback with diazepam induction, however, is the slow induction of sleep. Harmful drug effects on the neonates must be expected if the dose has to be increased in order to ensure sleep.
Midazolam for Induction of Anaesthesia in Outpatients: A Comparison with Thiopentone
Authors: Berggren L. , Eriksson I.
Published: January 2009

Midazolam, a new water‐soluble benzodiazepine, with an elimination half‐life of approximately 2 h, was compared with thiopentone for induction of general Anaesthesia in a randomized, single‐blind study. The patients were 60 healthy women undergoing legal abortion as outpatients. Midazolam provided smooth and reliable induction of Anaesthesia with few side‐effects. However, the induction time was considerably longer in the midazolam group (82.3 + 6.1) than in the thiopentone group (45.9 ±1.7 s). The dose of midazolam required for induction was 0.36±0.01 mg/kg, while that of thiopentone was 6.43 ±0.21 mg/kg. Apnoea occurred with a frequency of 10 % in the midazolam group and 55 % in the thiopentone group, but was of equal duration in both groups. Circulatory conditions were more stable during induction with midazolam, with a slower fall in blood pressure and no change in heart rate. The patients were breathing O2/N2O in proportions of 1:2.

To ensure adequate surgical anaesthesia, it was necessary to add halothane for short periods for all patients in the midazolam group and for 79% of the thiopentone group. Postoperatively, all patients who had received midazolam, but none induced with thiopentone, had anterograde amnesia; this lasted for more than 1 h. All patients in both groups could leave the hospital after routine postoperative observation for 3–4 h. Venous tolerance was good for both drugs.
Local Discomfort and Thrombophlebitis Following Intravenous Injection of Diazepam
Authors: Selander D. , Curelaru I. , Stekansson T.
Published: January 2009

Diazepam is frequently used for pre‐ and peroperalive sedation. However, at i.v. injection local pain and thrombophlebitis are not uncommon, probably due to tissue irritancy of the various organic solvents necessary to keep diazepam in aqueous solution. In this study the incidence of local adverse effects following i.v. injection of Diazemulsr̀, a new lipid emulsion formulation, was compared with that of Apozepam, a glycoferol‐waler solution. We found that the latter preparation caused local pain and thrombophlebitis as often as reported with propyleneglycol‐phenylcarbinol‐ethanol preparations (Stesolidr̀, Valiumr̀) and in a statistically higher incidence than the lipid emulsion form, which therefore seems more suitable for intravenous use.
Nitrous Oxide Activates the Supraspinal Pain Inhibition System
Authors: Komatsu T. , Shingu K. , Tomemori N. , Urabe N. , Mori K.
Published: January 2009

The neurophysiological mechanism of nitrous oxide‐induced analgesia was studied in decerebrate non‐anesthetized cats. Intra‐arterial injection of bradykinin was used as the test noxious stimulus and the neural response in the lateral funiculus of the spinal cord was measured by the multi‐unit recording technique. The effects of nitrous oxide on the neural activity of spinal cord were compared before and after the spinal cord transection. Nitrous oxide activated the spontaneous firing level, but depressed the bradykinin‐induced response. These effects were more significant before the cord transection than after it. These findings indicate that nitrous oxide exerts its analgesic action through both the direct intraspinal anti‐nociceptive action and an indirect action by activating the supraspinal descending inhibition system.
Antianalgesic Action of Thiamylal Sodium in Cats
Authors: Tomemori N. , Shingu K. , Komatsu T. , Urabe N. , Mori K.
Published: January 2009

The effects of thiamylal on the nociceptor‐driven neural activity in the spinal cord were studied in decerebrate, non‐anesthetized cats. Noxious stimulation was induced by the injection of bradykinin into the femoral artery and the neural response in the lateral funiculus was measured by the multi‐unit activity technique. The effects of thiamylal on the bradykinin‐induced response were compared before and after the spinal cord transection, above the recording site. Thiamylal, 5 mg/kg i.v., potentiated the response significantly before the cord transection and depressed it after the transection. These findings indicate that the antianalgesic action of thiamylal is induced at the spinal cord level: although this anesthetic agent does have a direct intraspinal depressant action, the multisynaptic neural network of the supraspinal pain inhibition system is more susceptible to the actions of anesthetics, and the depression of this descending system by thiamylal results in a release of spinal cord nociceptive neural mechanisms from the supraspinal control.
Naloxone does not Antagonize the Anesthetic‐Induced Depression of Nociceptor‐Driven Spinal Cord Response in Spinal Cats
Authors: Shingu K. , Osawa M. , Omatsu Y. , Komatsu T. , Urabe N. , Mori K.
Published: January 2009

The effects of several anesthetics on spinal cord nociceptive neural mechanisms and their interactions with the opiate antagonist, naloxone, were studied in acute, spinal cord transected cats. Intra‐arterial injection of bradykinin was used as the noxious test stimulus. Spontaneous activity and the neural response induced by bradykinin were recorded by the multi‐unit activity technique in the lateral funiculus of the spinal cord. Naloxone, 0.1 or 2.0 mg/kg i.v., had little effect on the bradykinin‐induced response, but enhanced the spontaneous firing of the lateral funiculus significantly. Fentanyl, 30 μg/kg i.v., depressed both the bradykinin‐induced response and spontaneous firing. These effects of fentanyl were antagonized completely by naloxone, 0.1 mg/kg i.v. Nitrous oxide, thiamylal, halothane and ether depressed the bradykinin‐induced response considerably, but it was not antagonized by naloxone, 0.1–2.0 mg/kg i.v. Enflurane had little effect on the bradykinin‐induced response. The effects of these anesthetics on spontaneous firing were divergent: nitrous oxide enhanced it while other drugs depressed it, to various degrees. All these data suggest that the neural and/or neurochemical mechanisms of anesthetic‐induced analgesia differ from mechanisms related to opioids.
Postoperative Analgesics for Superficial Surgery. Comparison of Four Analgesics
Authors: Tigerstedt I. , Leander P. , Tammisto T.
Published: January 2009

The efficacy of mild analgesics after 160 various superficial operations was studied by comparing intravenous lysine‐acetylsalicylate (LAS) 1.8 g, Litalginr̀ 4 ml (metamizole = dipyrone 2.0 g+pitophenone 8.0 mg) or paracetamol 0.5 g to oxycodone 4 mg. At 15 min postdrug, oxycodone 4 mg had the best peak effect but this significant (p<0.05) difference to mild analgesics disappeared at 30 min, and thereafter all test analgesics showed an equally low effect. Two‐thirds of the patients anaesthetized without peroperative analgesics needed pain relief when recovering from superficial surgery. The need for pain relief was lowest after varicose vein operations, 40% of the patients as compared to about 70% after other types of superficial surgery. In 42% of the patients requiring pain relief, the test analgesics alone gave sufficient pain relief. The rest needed an additional 5 mg of oxycodone, on average, to be comfortable. The combined use of mild analgesics and oxycodone for adequate pain relief did not seem to reduce the postdrug sedation as compared to oxycodone alone. The results indicate that in traditional clinical dosages LAS, dipyrone or paracetamol can substitute about 5 mgoxycodone but offer sufficient analgesia only in about 40% of the patients recovering from superficial surgery.
Design and Function of Tracheal Suction Catheters
Authors: Lomholt N.
Published: January 2009

Tracheal suction catheters damage the mucosa of the airway, due to both the pull from the vacuum and insertion of the catheter. The pull of the vacuum from a suction catheter was measured on a Mettler balance. An open side hole reduced the pull by around 90% and a distance of 1 mm gave a reduction of around 90%. The combination of one side hole and a 1 mm distance gave a 99% reduction of the pull. The difference between one or more side holes was measured. The suction efficacy was higher with a single side hole than with several side holes. On the basis of these measurements and a review of the literature, the principles were outlined for the construction of a suction catheter which provided maximum suction efficacy and caused minimum damage: (1) a moderate to strong vacuum was to be used; (2) the catheter was to have a single hole at the tip and a single side hole placed at the convex side of the angle; (3) both side hole and tip hole should be so constructed that the holes were kept at a distance from the mucosa; and (4) the tip should be angulated.
The New NL Tracheal Suction Catheter
Authors: Lomholt N.
Published: January 2009

When a tube with a vacuum is approached to the surface of a liquid, a suction cone is formed and the liquid is sucked into the tube. In the new NL tracheal suction catheter, this suction cone effect is used to transport secretions into its depressed suction holes. The catheter is angle‐tipped and has a U‐shaped depression around a single side hole at the angle. Four large holes near the edge of the tip hole are shown to be just as effective in reducing the pulling force from the tip hole as the depression around the side hole. The new catheter was compared with three commercially available suction catheters with regard to the maximum damaging eiiect and the suction eficacy. The force from each suction hole pulling a flat metal base was reduced from 3 to 33 times and the efficacy in sucking was increased in relation to the other catheters when egg‐white was used as a model for mucus. Angle‐tipped catheters are orientation‐dependent. The NL catheter was the least orientation‐dependent of the three angle‐tipped catheters tested. Histologic examination of the mucus sucked during a clinical test showed that the NL catheter caused less tracheobronchial damage than did the Rusch catheter.
Physostigmine for Post‐operative Somnolence After Diazepam‐Nitrous Oxide Anaesthesia.
Authors: Nilsson E. , Himberg J.‐J.
Published: January 2009

The antidotal effect of physostigmine in a dose of 1 mg and 2 mg was investigated in 44 patients after diazepam‐nitrous oxide anaesthesia The degree of recovery was estimated using the Bender Motor Gestalt test, the postoperative recovery scores, the changes in hand force, and the cerebral function monitor (CFM) trace. Diazepam plasma levels were also determined The improvement in the patients alertness assessed by psychomotoric tests and the CFM trace was significant, but the recovery of the vital functions measured by the recovery scores (PARS) was marginal. Thus the indications for physostigrnine in the treatment of postoperative somnolence induced by diazepam‐nitrous oxide are relative and only in grave oversedation with diazepam can physostigmine be recommended as an antidote.