bluuebunny/crossref_metadata_2025 huggingface dataset:
Phrenic and Vagal Nerve Activities during Spontaneous Respiration and Positive‐Pressure Ventilation
Authors: Jonzon Anders
Published: January 2009

Afferent vagal nerve activity from stretch‐receptors in the lung and efferent phrenic nerve activity were recorded during spontaneous respiration and during positive‐pressure ventilation with three different types of ventilators. During spontaneous respiration the efferent phrenic nerve activity slightly preceded the afferent vagal nerve activity. Volume‐controlled ventilation did not alter the phrenic nerve activity when the ventilation was set at a rate equal to that during spontaneous respiration, but afferent vagal volleys increased in duration. At higher frequencies of insufflation spontaneous inspiration was inhibited.

An increase in afferent vagal nerve activity and a concomitant slight decrease in efferent phrenic nerve activity were obtained during animal triggered pressure‐controlled ventilation.

High‐frequency positive‐pressure ventilation (HFPPV) gave rise to basal, non‐grouped activity in vagal afferents, causing inhibition of inspiration. During HFPPV, spontaneous respiration can take place on activation of other afferents to the respiratory centre.

Clinical aspects of respirator treatment from a neurophysiological standpoint are discussed.
High‐Frequency Positive‐Pressure Ventilation (HFPPV) Applied in Bronchoscopy under General Anaesthesia An Experimental Study
Authors: Borg Ulf , Eriksson Ivan , Lyttkens Leif , Nilsson Lars‐Göran , Sjöstrand Ulf
Published: January 2009

Techniques for ventilation in bronchoscopy under general anaesthesia using intermittent positive‐pressure ventilation directly via the fixed side‐arm of the open bronchoscope have recently been described by several authors. Our present technique utilizes a high pressure oxygen/nitrous oxide gas mixture which is obtained from a gas‐conditioning system. This gas is intermittently supplied at a high insufflation frequency to the side‐arm of the open bronchoscope.

In lung model experiments and experiments in dogs the use of Storz bronchoscopes 4–9 mm in diameter was studied. With the volumes of delivered gas kept constant, the lung model studies showed that the “intrapulmonary pressure” increases with decreasing insufflation frequencies; in parallel the “pulmonary ventilation” decreases due to increasing gas loss through the outer opening of the open bronchoscope. In both the dog and the lung model experiments increasing frequencies resulted in reduced pulmonary ventilation. Both of these studies showed that when the relative insufflation time was shortened from 32 to 22 % of the period time ventilation increased. As demonstrated previously, the central venous pressure and the pulmonary arterial pressure were not affected by this type of high‐frequency positive‐pressure ventilation.

It is concluded that this study favours an insufflation frequency (f) of 60 per min and a relative insufflation time (t%) of 22% to be used in the clinical situation.

If f/t% is kept at 60/22 in bronchoscopic HFPPV the driving gas pressure is the principal determinant of the total gas input and pneumatic valve function, which are the main factors in the generation of tidal volume and alveolar ventilation with this “open” ventilator system. Consequently, and as may be demonstrated clinically (Eriksson & Sjöstrand 1977a), the ventilation of the patient is regulated by the driving gas pressure. As there is no air entrainment with bronchoscopic HFPPV the oxygenation is regulated by means of the oxygen concentration in the oxygen/ nitrous oxide mixture delivered intermittently to the side‐arm of the bronchoscope.
Fresh Autotransfusion in Major Surgery
Authors: Benveniste Daniel , Lund Bjarne , Nielsen Jørgen , Pedersen J. E. poul
Published: January 2009

The purpose of this study was to investigate whether 600–800 ml of fresh autologous blood, withdrawn just before anesthesia and retransfused at the end of the operation, would reduce early postoperative anemia. Thirty‐nine patients undergoing abdominal hysterectomy were autotransfused, while 44, submitted to the same operation, served as controls. Appropriate amounts of lactated Ringer solution were infused during phlebotomy and operation. The cardiovascular system remained stable and diuresis high. Postoperative complications were few and did not prolong hospitalization. The mean peroperative blood loss per patient was 680 ml. Fresh autotransfusion did not improve early postoperative anemia.
Reduction of Cerebral Blood Flow and Oxygen Consumption with a Combination of Barbiturate Anaesthesia and Induced Hypothermia in the Rat
Authors: Nordström C.‐H. , Rehncrona S.
Published: January 2009

The influence of phenobarbitone anaesthesia on cerebral blood flow (CBF) and cerebral metabolic rate for oxygen (CMRo2) during hypothermia (23°C & 27°C) was studied in the rat, using a modification of the Kety & Schmidt (1948) technique and arterio‐venous differences for oxygen. Phenobarbitone (150 mg/kg) was found to decrease CMRo2 by 40–60% during hypothermia, when compared to N2O anaesthesia. At a body temperature of 23°C, and during phenobarbitone anaesthesia, CMRo2 was reduced to about 15% of normal control value (about 10.3 ml.100g‐l. min‐l). CBF was reduced to about 50% of the phenobarbitone control value but was similar to the value obtained with N2O anaesthesia at 22°C. It is concluded that the combination of phenobarbitone anaesthesia and hypothermia results in a more pronounced reduction in cerebral metabolic rate for oxygen than can be achieved by administration of barbiturates to normothermic animals, or by reducing body temperature by 15°C during superficial anaesthesia.
Flow Requirements in the Hafnia Modifications of the Mapleson Circuits during Spontaneous Respiration
Authors: Christensen K. N. , Thomsen A. , Hansen O. , Jørgensen S.
Published: January 2009

The Mapleson A, B, C and D circuits can be changed into non‐polluting circuits by employing continuous gas evacuation directly from the circuit, via an ejector flowmeter (Jørgensen 1974); Mapleson A and C circuits with this modification have been described previously as the Hafnia A and C circuits (Christensen 1976, Thomsen & Jørgensen 1976).

If evacuation from a closed reservoir is employed, total removal of the expired and surplus gases from the operating theatre is obtained (Jørgensen & Thomsen 1976). There will be resistance to expiration in all the circuits with a relief valve for the discharge of surplus gas. If surplus gas is continuously removed directlyfrom the anaesthetic circuit, the patient breathes in an air compartment at ambient pressure, as long as the removal rate equals the inflow of fresh gas. The relief valve is only included in the circuit to ensure that high pressures do not develop. As in any other circuit, the relief valve remains open except during controlled ventilation. A dumping valve may also be included as a safeguard against low pressures (Jørgensen & Thomsen 1976).

The flow requirements of the Hafnia B and D circuits and the corresponding Mapleson circuits have been studied in conscious, spontaneously breathing subjects, and the results are discussed in relation to the flow requirements of other semi‐closed systems.
The Use of Physostigmine as an Antidote in Tricyclic Anti‐depressant Intoxication
Authors: Aquilonius S.‐M. , Hedstrand U.
Published: January 2009

The value of physostigmine treatment of unconsciousness due to self‐poisoning by tricyclic antidepressant drugs (TAD) was evaluated in 10 patients, and the following conclusions are drawn: 1. A slow i.v. injection of 2 mg of physostigmine produces a clear‐cut increase in consciousness within 15 min if a TAD (or other drugs with central anticholinergic potencies) is mainly responsible for the poisoning. This “test dose” can give valuable diagnostic information. 2. Repeated i.v. injections seem of little practical value, since they may be expected to produce a state with rapid shifts in the level of consciousness. J. If the test dose has a positive effect, immediate i.v. infusion of 4 mg physostigmine/h will maintain a high level of consciousness. Infusion should be stopped every sixth hour for about 30 min to check whether the level of consciousness still falls upon withdrawal of therapy. 4. In cases of massive TAD overdosage, i.v. injection of physostigmine may increase the risk of grand mal seizures. 5. No signs of enhanced peripheral cholinergic activity following physostigmine are seen if 30 mg of propantheline is given i.v. every sixth hour. 6. No evidence has been produced that the mortality rate in TAD poisoning is lower following physostigmine treatment than with conventional supportive care. There must be the usual preparedness for cardiac complications.
Concentration and Elimination of Anaesthetic Gases in Operating Theatres Influence of Anaesthesia Apparatus Leakages
Authors: Berner Ole
Published: January 2009

Halothane and nitrous oxide (N2O) concentrations were measured in operating theatres, in the areas corresponding to the inhalation zones or the anaesthetists and operating nurses. The measurements were performed in an operating theatre with a non‐recirculating air exchange rate of 20/h. This was performed partly in model experiments and partly during the administration of anaesthesia by intubation.

In the model experiments, the measurements were taken both with and without a specially constructed scavenging system. During anaesthesia, the measurements were taken exclusively with the scavenging system, although well‐defined leakages were fitted into the otherwise gas‐tight anaesthetic system. The results were supplemented by smoke experiments which showed the air distribution patterns.

The investigation showed that the gases were concentrated over and around the operating table. Activities during surgery diluted this concentration. Furthermore, it was shown that leakage in the anaesthetic system significantly influences the achieving of a low gas‐air mixture. Halothane concentrations in the inhalation zone of the anaesthetist and operating nurse can be reduced to 0.02 and 0.01 p.p m. respectively, if the anaesthetic system is completely gas‐tight.
A Comparative Study of Halothane and Enflurane in Paediatric Outpatient Anaesthesia
Authors: Davidson Sally H.
Published: January 2009

Two groups of paediatric patients, consisting of 40 patients each, were studied with regard to anaesthesia induction and recovery. Group H was given halothane and Group E received enflurane. The induction time was similar for the two groups. Enflurane had, on average, a shorter recovery time (17±4 min) than halothane (26±4min) (P<0.05).

The mean dose of anaesthetic given, expressed as the product of inspired concentration times minute ventilation, was 2.3±0.2 1 100% halothane and 2.8±0.2 1 100% enflurane. If one assumes that the minimum alveolar concentration (MAC) value for enflurane twice that of halothane, group E received a less potent anaesthetic dose. This might explain the similar induction times, and, in part, the shorter recovery time for enflurane in this study.

No difference was noted between the two agents with regard to post‐operative nausea and vomiting or restlessness.
The Effects of Antihypertensive Medication on the Control of the Cardiovascular System during Halothane Anaesthesia in Rats
Authors: Kaukinen S. , Ylitalo P.
Published: January 2009

The effects of hydralazine, clonidine, propranolol and methyldopa medication on the control of the circulatory system during halothane anaesthesia were studied in spontaneously hypertensive (SH) rats. Special attention was directed to the problem of circulatory emergencies. Under 1 and 3% halothane anaesthesia, the mean arterial pressure was lowest in methyldopa‐treated rats. During 3% anaesthesia, plasma renin activity was markedly increased in the methyldopa group and decreased in the propranolol group. Hydralazine medication suppressed the pressor responses to dopamine and metaraminol, whereas clonidine, propranolol and methyldopa increased the response to dopamine. These sympathetic agents induced more cardiac arrhythmias in SH controls than in normotensive ones. These arrhythmias were antagonized by hydralazine. The SH controls also tolerated haemorrhagic shock more poorly than did normotensive control rats. Among the pretreated animals, tolerance to this shock was highest in hydralazine‐and clonidine‐treated animals and lowest in the methyldopa group.

The results suggest that during halothane anaesthesia SH rats are more prone to disturbances in the control of circulation than are normotensive controls. Hydralazine and, to a lesser extent, clonidine have a protective action against these disturbances, but the effect of methyldopa seems to be disadvantageous.
The Effect of Halothane on the Distribution of Cardiac Output and Organ Blood Flow in the Hypovolemic Dog
Authors: Ahlgren I. , Aronsen K. F. , Björkman I. , Wetterlin S.
Published: January 2009

The circulatory effect of halothane anesthesia given to moderately hypovolemic dogs (blood loss 25 ml/kg b.w.) was investigated using the radioactive microsphere technique. The effect of the anesthetic was reflected by a decrease in the arterial mean blood pressure and a reduced blood flow to the heart, whereas the blood flows to other organs did not change significantly but were well preserved in vital organs (brain, kidneys, liver and lungs). The effect on the circulation of reinfusing the withdrawn blood was also studied.
The Effect of Halothane on the Distribution of Cardiac Output and Organ Blood Flows in the Hemorrhagic, Hypotensive Dog
Authors: Ahlgren I. , Aronsen K. F. , Björkman I.
Published: January 2009

Halothane was given to dogs which had been bled to an arterial mean blood pressure of 60 mmHg, and the circulatory effects were studied with the aid of the radioactive microsphere technique. The cardiac output and coronary blood flow were well maintained, whereas the arterial mean blood pressure was slightly, and the stroke volume markedly increased, indicating an improved heart function. The blood flows to the brain, lungs, liver and kidneys were well preserved throughout the anesthesia. The effect of retransfusing the withdrawn blood was also studied, and it resulted in an increased cardiac output, arterial mean blood pressure and increased blood flows to the heart, lungs, spleen, bowel and liver.
The Effect of Surgical Stress on Haemodynamics During Neurolept Anaesthesia
Authors: Santesson Joakim , Järnberg Per‐Olof , Arnér Staffan
Published: January 2009

The influence of surgical stress on haemodynamics during neurolept anaesthesia (NLA) was studied in ten patients, while they were awake, under anaesthesia prior to surgery and peroperatively. Systemic arterial, pulmonary arterial, right atrial and pulmonary capillary wedge pressures, as well as cardiac output (Qt), arterial oxygen content and mixed venous oxygen content, were measured. Systemic and pulmonary vascular resistances, arterial‐venous oxygen content difference (AVD), oxygen consumption (vo2 and cardiac index (CI) were calculated.

On institution of anaesthesia, CI fell from 2.8 ±.11 /min. m2 to 2.5±0.2 l /min.m2 and systolic arterial pressure (SBP) fell from 13.4±0.5 kPa to 10.2±0.3 kPa. During surgery CI rose to 3.3±0.1 1/min.m2 and SBP rose to 15.7±0.6 kPa. Prior to anaesthesia, AVD was 40.2±0.2 ml/l Under anaesthesia prior to surgery, AVD did not change, but vO2 declined from 207±13 ml/min to 171±10 ml/min. During surgery, AVD fell to 30.5±0.3 ml/l, while Vo2 remained unchanged.

It is concluded that NLA has a direct metabolic depressant effect and, in association with surgery, is accompanied by hyperkinetic circulation.
Cardiovascular Effects of Local Adrenaline Infiltration During Neurolept Analgesia and Adrenergic Beta‐Receptor Blockade in Man
Authors: Pöntinen P. J.
Published: January 2009

The adrenergic beta‐receptor blocking drug, alprenolol, was given together with atropine to 15 patients during neurolept analgesia (NLA) in order to prevent adrenaline‐induced cardiac arrhythmias. Four patients operated on without adrenergic beta‐receptor blockade formed the control group. Three of them developed tachyarrhythmias, ventricular tachycardia, multifocal ventricular extrasystoles and supraventricular tachycardia. All these arrhythmias were terminated by the adrenergic beta‐receptor blocking drug, propranolol. The fourth patient developed a temporary sinus tachycardia which did not require any treatment.

The adrenergic beta‐receptor blockade induced a slight increase in pulse rate with almost no change in arterial blood pressure. The incidence of arrhythmias due to adrenaline infiltration was much less in this group. There was one supra‐ventricular tachycardia and scattered ventricular extrasystoles in two other patients.

NLA alone does not protect the heart against adrenaline‐induced arrhythmias. It does, however, seem to be compatible with an adrenergic beta‐receptor blockade, which in turn provides partial protection against adrenaline‐induced arrhythmias. The occasionally developing arrhythmias can then be terminated with specific adrenergic beta blockers.
Effect of Naloxone Reversal on CO2Output, Oxygen Uptake and Cardiac Index During Recovery from Fentanyl‐Supplemented Anaesthesia
Authors: Tigerstedt Irma , Tammisto Tapani
Published: January 2009

For reversal of contingent residual narcotic depression after fentanyl administration during balanced anaesthesia, the effect of 0.08 mg of naloxone on CO2output, O2uptake and cardiac index was studied immediately after extubation. This dose maintained normocapnia (5.7 kPa) during early recovery, while in the control group slight hypercapnia was present (6.0 kPa). No significant differences, however, could be detected between the groups in CO2output, O2uptake or cardiac index. When 0.16 mg of naloxone was given to six other patients 10 min after the anaesthesia, when spontaneous respiration had stabilized on the same level as in the control group, significant increases in respiratory minute volume and rate and CO2output were recorded as compared with the respective prenaloxone levels. O2uptake increased with simultaneous improvement of PaO2and the cardiac index also increased significantly. A slight but highly significant increase in CO2output was detected after 0.16 mg of naloxone in six patients during anaesthesia and volume‐controlled IPPV. A significant increase in PacO2was also measured. These findings indicate that if naloxone is used postoperatively, a significant metabolic increase may take place due to increased muscular work, restlessness and shivering. Ventilation and cardiac output were adequate for demand under present conditions using 2 μg/kg of naloxone, but careful titration of naloxone is recommended in order to avoid harmful metabolic changes.
Acute Effects of Furosemide and Mannitol on Central Haemodynamics in the Early Postoperative Period
Authors: Järnberg Per‐Olof
Published: January 2009

The effects of furosemide and mannitol on central haemodynamics in the early postoperative period were investigated in 16 patients, who had undergone uppcr abdominal surgery. Measurements were performed prior to, and then 10, 30, 50 and 90 min after postoperative drug administration. Furosemide administration resulted in reductions of cardiac output, mean pulmonary arterial, pulmonary capillary wedge, and mean systemic arterial pressures, while systemic vascular resistance increased. Mannitol administration on the other hand, caused increases of cardiac output, mean pulmonary arterial and pulmonary capillary wedge pressures. Systemic vascular resistance decreased. It is concluded that mannitol should be used as the diuretic of choice in the treatment of postoperative (post‐traumatic) oliguria in patients without known cardiovascular disease.
Effects of Ventilation with Large Tidal Volumes or Positive End‐Expiratory Pressure on Cardiorespiratory Function in Anesthetized Obese Patients
Authors: Eriksen Jørgn , Andersen Jens , Rasmussen Jens Peter , Sørensen Birgit
Published: January 2009

The cardiorespiratory effects of ventilation with large tidal volumes (LTV) or positive end‐expiratory pressure (PEEP) were investigated in 10 extremely obese patients during anesthesia for a jejuno‐ileal by‐pass operation.

Elevation of the tidal volume by 35% and insertion of a dead space (LTV‐group: five patients) or applying a PEEP of 1.0 kPa (PEEP‐group: five patients) resulted in significant rises in arterial oxygen tensions (Pao2) of 87.4% and 72.4%, respectively. The alveolar‐arterial oxygen tension differences (P(a‐a)o2) decreased by 29.2% in the LTV‐group and 25.6% in the PEEP‐group when compared to control values. No significant differences were found between the groups in Pao2 or P(A‐a)o2.

PEEP‐ventilation caused a maximal increase in compliance of 42.6%, but there was an increase of only 20.8% in the LTV‐group.

Stroke index (the impedance cardiography method) decreased by 19.7% in the PEEP‐group, whereas no changes occurred in the LTV‐group. The decrease in stroke index was probably due to a reduction in venous return, as reflected in the systolic time intervals. In the PEEP‐group a prolongation of the pre‐ejection period (PEP) was observed, causing an increase in the PEP/LVET‐ratio of 41.2%. A 13.8% increase in PEP/LVET‐ratio was found in the LTV‐group.

In spite of the increased arterial oxygen contents, no improvements in arterial oxygen delivery were found in either of the groups.
Cerebral Metabolic Rate of Oxygen (CMRO2) in the Acute Phase of Brain Injury
Authors: Cold Georg E.
Published: January 2009

In 22 comatose patients with acute brain injury, the cerebral metabolic rate of oxygen (CMRo2) was calculated as the product of the hemispheric cerebral blood flow (CBF) and the arteriovenous oxygen content difference. All patients were subjected to moderate sedation without barbiturates, normothermia and respiratory treatment. The CBF was calculated by the 133xenon washout method as the average of 16 regions. The results indicate high jugular venous oxygen tension and, in some studies, very low oxygen consumption. A critical, low CMRo2 was not found, and values of about 0.4 ml/100 g/min were compatible with restitution of intellectual function. The CMRo2 was unrelated to the clinical outcome and to the time after the trauma. In bilateral studies, the lowest values were measured in the most severely injured hemisphere.
Althesin®in Neurosurgical Patients: Effects on Cerebral Hernodynamics and Metabolism
Authors: Rasmussen Niels J. , Rosendal Tage , Overgaard Jørn
Published: January 2009

The effect of althesin 0.5 ml/10 kg on arterial blood pressure, intracranial pressure, cerebral blood flow and oxygen uptake was studied on 19 occasions in 16 patients with varied cerebral pathology.

Cerebral blood flow (CBF) was measured using the intracarotid 133xenon method and a 35‐channel scintillation detector after cannulation of the internal carotid artery, the internal jugular bulb and the lateral cerebral ventricle. Arterial and intracranial pressures were recorded continuously. Blood gas tensions were measured in simultaneously drawn samples from the internal carotid artery and the jugular bulb. Cerebral oxygen uptake was calculated from the product of CBF and arteriovenous oxygen content difference.

Control values were obtained with the patients under a basic general anesthesia, consisting of N2O/O2 pancuronium. The effect of a bolus injection of althesin was then studied 1 and 20 min after the injection. A significant reduction in intracranial pressure, cerebral blood flow and metabolism at 1 min was found to have essentially subsided 20 min after the injection. In patients with focal brain damage, regional flow analysis revealed a paradoxical increase in flow after althesin in the areas corresponding to the focus.
Cerebral Autoregulation in Unconscious Patients with Brain Injury
Authors: Cold Georg Emil , Jensen Finn Taagehøj
Published: January 2009

In 18 unconscious patients with traumatic brain injury, the cerebral autoregulation was tested during the first 2–3 weeks after the acute trauma. Regional cerebral blood flow (rCBF) was measured by the intra‐arterial 133xenon washout method before and after an increase of about 20% in the mean arterial blood pressure (MABP) by angiotensin. The difference between MABP and intraventricular pressure (IVP) was used as cerebral perfusion pressure (PP). Simultaneously, ventricular fluid pH, lactate and pyruvate were measured.

Regional loss of autoregulation indicated by a 20% flow increase was observed in 29 out of 35 studies (83%), while hemispheric loss of autoregulation was observed in only one study. The results of the autoregulation tests were unrelated to the clinical outcome, the presence of brain‐stem lesion, and the ventricular fluid pH, lactate and lactate/pyruvate ratio. In repeated studies, a gradual normalization of the autoregulation was observed about 5 days after the acute trauma.
The Placental Transfer of Pancuronium and its Pharmacokinetics During Caesarian Section
Authors: Duvaldestin P. , Demetriou M. , Henzel D. , Desmonts J. M.
Published: January 2009

The placental transfer of pancuronium and its pharmacokinetics were investigated in 33 pregnant women undergoing caesarean section. After a single intravenous injection of 60–100 μg/kg, the serum pancuronium concentration was measured (using a fluorimetric method) in serial samples of maternal blood and in umbilical arterial and venous blood obtained at the time of delivery. Detectable amounts of pancuronium were found in all foetal blood samples. The cord vein to maternal concentration ratio of pancuronium averaged 0.22; it increased significantly with prolongation of the induction‐delivery interval. The mean cord arterial to cord venous ratio of pancuronium was 0.66 (range 0.2–1.0), suggesting foetal drug uptake. Apgar scores were above 9 at 5 min in all cases, and there was no clinical evidence of any adverse effect in the newborns which could be related to the presence of a muscle relaxant.

The distribution and elimination of pancuronium were compared in 18 normal subjects and in 21 women undergoing caesarean section. Plasma pancuronium concentration declined biexponentially with fast (α) and slow (β) phases, with half‐lives in the control group of 13 min and 146 min (mean values), respectively. In the women undergoing caesarean section, t 1/2 α was not changed, while t 1/2 β decreased slightly but significantly to 114 min.
Treatment of Respiratory Insufficiency in Infants Using Nasal CPAP and a Gas Jet
Authors: Kamper J. , Brendstrup A.
Published: January 2009

A light‐weight system for continuous positive airway pressure (CPAP) based on a nasal vestibular cannula and a miniature gas jet has been tried out in 29 newborns with severe idiopathic respiratory distress syndrome (IRDS) and nine infants suffering from respiratory insufficiency caused by lower respiratory tract infections. In infants with IRDS, a permanent effect was achieved in 20% when the birth weight was below 1501 g, and in 74% when the birth weight was higher. The infants with lower respiratory tract infections all recovered without further ventilatory support. Significant complications occurred in only two infants, both of whom developed pneumothorax. The system forms a simple and safe alternative to existing nasal CPAP systems suitable for use in newborns as well as older infants with lung diseases resulting in alveolar collapse.
Effects of Enflurane on Haemodynamics and Oxygen Uptake with Special Reference to the Influence of Surgical Stress
Authors: Santesson J. , Irestedt L. , Järnberg P.‐O. , Norlander O.
Published: January 2009

The influence on central haemodynamics of enflurane, in uniform anaesthetic concentration (1.5 MAC), was studied in 10 normocapnic patients undergoing upper abdominal surgery. The patients were studied awake, during anaesthesia prior to surgery, and during surgery. On institution of anaesthesia, cardiac output (Qt) fell from 5.05±0.51 to 4.12±0.15 l/min and systemic vascular resistance (SVR) decreased from 2.36±0.22 to 1.93±0.18 kPa min 1‐‐3 The arterio‐venous oxygen content difference (AVD) did not change. On commencement of surgery, AVD diminished from 38.5±2.6 to 30.8±1.9 ml/min and QT rose to 5.82±0.46 l/min, while SVR remained unchanged. It is concluded that the fall in Qr seen during enflurane anaesthesia is caused by a diminished tissue oxygen demand. It is also suggested that enflurane acts as an α‐blocking agent.
Influence of Morphine Anaesthesia on the Endocrine‐Metabolic Response to Open‐Heart Surgery
Authors: Brandt M. R. , Korshin J. , Hansen A. Prange , Hummer L. , Madsen S. Nistrup , Rygg I. , Kehlet H.
Published: January 2009

Twelve patients scheduled for aortic valve replacement during extracorporal circulation were randomly allocated to either morphine anaesthesia or fluroxene anaesthesia. Morphine in a total dose of 4 mg/kg was administered bcforc skin incision. At the start of extracorporal circulation all patients received 25 g glucose intravascularly. The endocrine‐metabolic response to surgery, as expressed by changes in plasma ACTH, cortisol, insulin, growth hormone, cyclic adenosine ‐3′, ‐5′‐monophosphate (cyclic AMP), glucose, free fatty acids, blood b‐hydroxy‐butyrate and cumulative nitrogen balance was measured before and during anaesthesia and surgery, and on the first five post‐operative days.

It was found that morphine anaesthesia blocked the increase in ACTH, cortisol, growth hormone, cyclic AMP, and glucose during surgery. However, after initiation of extracorporal circulation only ACTH, cortisol, and, to a lesser degree, the glucose and insulin response to glucose were lowered by morphine anaesthesia. From the first to the fifth days after operation no differences between the two groups could be demonstrated in any parameter. Cumulative nitrogen balance was similar in the two groups.

It is concluded that morphine in large doses administered bcfore skin incision inhibits the initial endocrine‐metabolic response to open‐heart surgery, but that the effect is short‐lasting and without effect on overall postoperative prokin catabolism.
Arrhythmias During Halothane Anesthesia. III.: The Influence of Barbiturates
Authors: Andersen J. R. , Eikard B.
Published: January 2009

The effect of barbiturates on cardiac rate and rhythm during halothane ancsthesia without intubation was studied in a triple‐blind, randomized trial with 28 patients. The test group was premedicated with pentobarbital and induced with thiopental, while the control group was anesthetized with halothane and nitrous oxide only.

There was a significant preponderance of sinus‐bradycardia and supraventricular disturbances in the control group.

It is concluded that the use of barbiturates is advantageous because of their ability to suppress enhanced vagal tone.
Effect of Anaesthesia and Open‐Heart Surgery on Lymphocyte Responses to Phytohaemagglutinin and Concanavalin A
Authors: Salo M.
Published: January 2009

Cell‐mediated immunity as a part of the immune host defence mechanisms was studied in 32 patients undergoing open‐heart surgery with cardiopulmonary bypass. The thiopentone + N2O + O2 + droperidol + fentanyl + pancuronium anaesthesia did not suppress the phytohaemagglutinin (PHA) and concanavalin A (Con A) responses of lymphocytes in whole blood culture during the first 1.5–2 h of anaesthesia before the beginning of surgery. In contrast, a clear decrease occurred in the PHA and Con A responses after the start of surgery, with a further decrease during extracorporeal circulation. After anaesthesia and operation in the patients subjected to coronary artery and valve replacement surgery, the PHA and Con A responses were only 1–5% of the preoperative day values, while the decrease was smaller in the patients who underwent closure of an atrial septal defect (ASD). The lymphocytic responses in the coronary artery surgery group returned to the preoperative day values in 2–3 months. In the valve replacement and ASD closure groups, complete recovery was not attained during the follow‐up period of 7 days. The findings in this study indicate that, compared with the role of anaesthesia, the role of operative procedure is decisive in the decrease of the lymphocytic responses associated with anaesthesia and surgery. The correlation between decreased mitogen responses and different postoperative complications remains to be established.
Low Consumption Mass Spectrometer Inlet System for Respiratory Measurements
Authors: Grønlund J.
Published: January 2009

The traditional mass spectrometer inlet systems adapted for measurement of gas partial pressure have a considerable gas consumption. This is a major drawback when they are used in closed respiratory systems. In the present paper, a membrane‐covered inlet system with a very low gas consumption is described. We also report on the response time and relative sensitivity of the system to different gases.
Serum Cholinesterase Variants in the Danish Population
Authors: Hanel H. K. , Viby‐Mogensen J. , de Muckadell O. B. Schaffalitzky
Published: January 2009

A total of 1278 adult patients were screened for serum cholinesterase (E.C. 3.1.1.8) variants. The following inhibitors were used for phenotyping of variants: dibucaine, fluoride, chloride, and urea.

The observed incidence of cholinesterase variants in the Danish population was similar to that found in other European countries.
Influence of “Lytic Cocktail” on Blood Flow and Oxygen Consumption in the Rat Brain
Authors: Berntman Leif , Carlsson Christer
Published: January 2009

The influence of a sedative dose of “lytic cocktail” (chlorpromazine, promethazine and pethidine) on cerebral blood flow (CBF) and oxygen consumption (CMRo2) was tested in artificially ventilated rats, maintained on either 70% N2 or 70% N2O. When given alone, the lytic cocktail had no significant effect on CBF or CMRo2. However, in the presence of nitrous oxide there was a 25% reduction in blood flow and oxygen consumption.
Hepatic Release of Fluoride from Halothane under Hypoxic and Non‐Hypoxic Conditions in the Dog
Authors: Andreen Magna , Irestedt Lars
Published: January 2009

Six dogs were subjected to halothane anaesthesia under hypoxic and non‐hypoxic conditions. Plasma fluoride levels in hepatic venous and arterial blood, as well as blood flow to the liver, were measured during anaesthesia. The amount of fluoride released by the liver could thus be calculated. Release of fluoride took place in all animals during non‐hypoxic halothane anaesthesia. The amount released varied between the individual animals and in three of them it rose further during hypoxic anaesthesia. The occurrence of defluorination of halothane, even under non‐hypoxic conditions, may indicate a reductive metabolism in at least some parts of the liver. The significance of this hypothesis is discussed.
In VivoLung Uptake of Lidocaine in Pigs
Authors: Bertler ÅKe , Lewis David H. , Löfström J. Bertil , Post Claes
Published: January 2009

A mixture of14C‐labelled lidocaine and indocyanine green dye (IG) (Cardiogreen®) was injected as a bolus into the pulmonary artery in pigs (15–25 kg). Time‐concentration curves for both substances were constructed from 2/s blood samples taken from the common carotid artery for approximately 20 s. The extraction of lidocaine in each sample and the 95% first passage uptake (FPU) were calculated, assuming that IG is inert with respect to the lung and that it remains within the vascular compartment. The IG curves were also used to calculate cardiac output. The acid‐base status and arterial blood pressure or ECG were also followed. Earli animal was given two injections.

When 0.5 mg/kg b.w. lidocaine was injected, FPU was 41±3%; at a dose of 2 mg/kg b.w., FPU was 28±3% (P<0.05). The initial extraction during the first 2 s after appearance of the substances was approximately 80%. This level declined with subsequent samples, and the decline was equally rapid at both dose levels.
Sympathetic Nervous System Response to Lidocaine Induced Seizures in Cats
Authors: Rosenbaum K. J. , Sapthavichaikul S. , Skovsted P.
Published: January 2009

The effect on arterial pressure, EEG, preganglionic sympathetic nervous activity and pulse rate of repeated intravenous administrations of lidocaine (3 mg/kg) was investigated in cats anaesthetized with nitrous oxide. A continuous high voltage, burst‐suppression EEG indicating constant seizure activity was found, whereas arterial pressure and sympathetic nervous activity did not change significantly. Although the onset of EEG seizure activity did not change the mean sympathetic activity level, the pattern of firing changed dramatically as every EEG seizure triggered a burst of sympathetic impulses. Barostatic reflexes were active after lidocaine administration unless seizure activity occurred. Thiopental 5 mg/kg given intravenously to cats during continuous lidocaine‐induced EEG seizures always abolished the seizure activity without excessive depression of arterial pressure.
Adsorption of Insulin by Infusion Materials
Authors: Schildt R. , Ahlgren T. , Berghem L. , Wendt Y.
Published: January 2009

Doubt about insulin adsorption has been an obstacle to rational insulin treatment by i.v. infusion. The influence of several factors on adsorption was therefore studied using a radioimmunoassay technique to determine insulin levels. When 8 to 128 IU of insulin were added to 500– and 1,000‐ml containers, a linear relationship was found between the amount added and the amount delivered to the patient, permitting the design of a practical nomogram. In other experiments, 32 IU of insulin was added to 1,000 ml containers. The type of insulin did not influence adsorption. Half of the 32 IU added to soda‐glass and siliconized bottles were adsorbed, while plastic containers adsorbed less. Neither the type of infusion solution (except for 60% glucose), nor the type of infusion set influenced adsorption. Human serum albumin prevented adsorption only incompletely.
Hypoxia‐induced Pulmonary Vasoconstriction in Man: Inhibition due to Diethyl Ether and Halothane Anesthesia
Authors: Bjertnæs L. J.
Published: January 2009

Impaired pulmonary gas exchange resulting in arterial hypoxemia is frequently observed in patients during general anesthesia. Recent animal investigations have revealed that pulmonary hypoxia‐induced vasoconstriction (a local mechanism which redistributes pulmonary blood flow from poorly to more amply ventilated regions) is abolished by commonly used inhalation anesthetics. Injectable anesthetics do not have this effect.

The present work was undertaken to study whether pulmonary vasoconstriction in response to ventilation hypoxia could be elicted in man during intravenous anesthesia, and to find out whether any response thus obtained is reduced by diethyl ether and halothane. Under intravenous anesthesia, unilateral hypoxia (UH) was induced in two groups of young men by ventilating one lung, the test lung, with N2 and the other with O2. In both groups the time period of UH was subdivided into two sequences, one sequence with and one without inhalation anesthesia. In 10 subjects (group A), inhalation anesthesia was administered during the second sequence, and in 7 subjects (group B), inhalation anesthesia was given during the first sequence. The blood flow distribution (BFD) to the test lung during air breathing and following each of the two sequences of UH was determined by lung scintigraphy. The median test lung BFD in group A decreased from 49% (range 40–45%) of total pulmonary blood flow to 24.5% (range 19–32%) during UH. By superimposing ipsilateral inhalation anesthesia, it increased to 34% (range 27–48%). The increase was significant both for the diethyl ether and halothane subgroups. BFD to the test lung during the first period of UH was significantly higher during diethyl ether or halothane administration (group B) than during administration of intravenous anesthesia only (group A). The damping effect of inhalation anesthetics on the response to hypoxia was demonstrated at blood concentrations comparable to those used in clinical anesthesia. It is therefore likely that inhibition of hypoxia‐induced pulmonary vasoconstriction contributes to the development of arterial hypoxemia during diethyl ether and halothane anesthesia in man.
Longitudinal Spread of Intraneurally Injected Local Anesthetics: An Experimental Study of the Initial Neural Distribution Following Intraneural Injections
Authors: Selander D. , Sjöstrand J.
Published: January 2009

Unexpected spinal anesthesia, occurring after peripheral nerve blocks close to the spine, may be caused by a centripetal spread of the local anesthetic along the injected nerve to the spinal cord. In order to analyze the pathway of such a spread, a radioactive local anesthetic mixed with a fluorescent dye was injected into different compartments of the rabbit sciatic nerve, and the early distribution of these tracers was studied by scintillation counting and fluorescence microscopy. Epineurial (extrafascicular) injections were of low injection pressure (25–60 mmHg) (3.3–7.9 kPa) and limited spread, while endoneurial (intrafascicular) injections reached higher pressures (300–750 mmHg) (39.9–99.7 kPa) and caused a rapid spread over long distances within the fascicle. The sacral plexus seemed difficult to pass. However, 20% of endoneurial injections reached the spinal cord, where the injectate primarily spread in the thin subpial space.

Our experimental findings suggest that intraneural injections of local anesthetics are responsible for the reported cases of unexpected spinal anesthesia due to inadvertent intrafascicular spread. Although intrafascicular injections are rarely made, we recommend that intraneural injections of local anesthetics or other solutions close to the spine should be avoided, as they may cause unexpected spinal anesthesia or lesion of the cord.
Residual Nitrous Oxide in Operating Room Personnel
Authors: Korttila K. , Pfäffli P. , Ertama P.
Published: January 2009

The concentrations of nitrous oxide in the blood and end‐tidal air of 10 operating‐room nurses were assayed by gas chromatography immediately and 1, 2, 5, and 21 h after 3 hours of exposure to an average of 380 ppm of nitrous oxide in operating‐room air. In the second trial the nurses' end‐tidal air concentrations of nitrous oxide were assayed on Monday, Wednesday, Friday and Sunday morning, and on Sunday afternoon and evening to reveal a possible accumulation of nitrous oxide during a routine week. After cessation of exposure there was a rapid decrease in the blood concentrations of nitrous oxide during the first hour (from 153±110 μg/1 to 48±20 μg/1 at 1 h; means ± s.d.), followed by a slower decrease. Small amounts (mean±s.d.: 18±6 μg/1) of nitrous oxide were still measurable on the following morning 21 h after exposure. At 2 or 5 h after exposure there was an increase in blood and end‐tidal air concentrations of nitrous oxide in seven and nine nurses, respectively. The end‐tidal air concentrations of nitrous oxide were greater on Wednesday (22±7 μg/1) than on Monday morning (8.4±1.5 μg/1), but on Friday they were similar to those measured on Monday morning. The concentrations measured on Sunday, i.e. 2 days after exposure, were similar (average 15 μg/1) to those measured during the week. It is concluded that, after cessation of exposure to nitrous oxide, there is a rapid decrease in the concentrations in blood and end‐tidal air, but small amounts of nitrous oxide remain in the body for at least 3 days after cessation of exposure.
Untoward Effects of Ketamine Combined with Diazepam for Supplementing Conduction Anaesthesia in Young and Middle‐Aged Adults
Authors: Korttila K. , Levänen J.
Published: January 2009

Fifty‐six young and 29 middle‐aged adults who were scheduled for lower abdominal, anorectal or extremity surgery under epidural, sacral or brachial plexus blockades received intravenous analgesic or anaesthetic doses of ketamine, combined with diazepam, immediately before the start of the operation. Forty‐one patients received no supplementary drugs for the conduction anaesthesia and were divided into two groups of controls. On the day following the operation, all the patients were asked about their postanaesthetic reactions and their acceptance of the anaesthetic technique, and the nursing staff expressed their opinion on the amount of work and supervision needed during the post‐operative care of the patients. Administration of ketamine 0.5 mg/kg with diazepam 0.15 mg/kg to young or middle‐aged patients was not associated with more side‐effects or a greater need for post‐operative care and supervision than in the control groups. Administration of anaesthetic doses of ketamine 1.5 mg/kg and 3.0 mg/kg with 0.15 mg/kg and 0.3 mg/kg of diazepam, respectively, caused significantly (P<0.05) more post‐operative anxiety and confusion, as well as a significantly greater need for post‐operative care and supervision than in the control patients. It is concluded that, in young or middle‐aged patients, supplementing conduction anaesthesia with ketamine 0.5 mg/kg plus diazepam 0.15 mg/kg is not associated with the untoward effects which can be expected after anaesthetic doses of 1.5 mg/kg (or more) of ketamine.
The Combined Effects of Antihypertensive Drugs and Anaesthetics (Halothane and Ketamine) on the Isolated Heart
Authors: Kaukinen S.
Published: January 2009

The effects of three concentrations of halothane or ketamine were investigated on isolated rabbit hearts, which were perfused with hydralazine, clonidine, propranolol or methyldopa. In hearts not subjected to the influence of an anaesthetic, clonidine was the only drug stimulating myocardial function. In those perfused with halothane or ketamine alone, both anaesthetics exerted a negative chronotropic and inotropic action in a dose‐related manner. Ketamine markedly increased the coronary flow. Clonidine distinctly reduced the myocardial depression caused by halothane or ketamine. Hydralazine had no marked effects with either of these anaesthetics, except that it sensitized the hearts to the arrhythmic action of a high concentration of halothane. Propranolol, when combined with halothane, aggravated myocardial depression and decreased coronary flow. With ketamine, propranolol caused no other harmful interactions, apart from inhibiting the increase in coronary flow caused by this anaesthetic. Methyldopa intensified the myocardial depression induced by halothane, but tended to diminish that caused by ketamine. The results suggest that clonidine has a stimulatory cardiac action when combined with either of these anaesthetics. Disadvantageous interactions may exist between methyldopa or propranolol and halothane.
Central Haemodynamics during Induction of Neurolept Anaesthesia in Patients with Arteriosclerotic Heart Disease
Authors: Bille‐Brahe N. E. , Sørensen M. Bredgaard , Mondorf T. , Engell H. C.
Published: January 2009

The haemodynamic changes occurring during induction of neurolept anaesthesia and intubation in patients with reduced cardiac reserve were compared with the haemodynamic changes observed prior to operation during the stress of moderate physical exercise in the same patients. Anaesthesia consisted of droperidolum NFN (Dehydrobenzperidol®), fentanyli citras NFN (Haldid®) and nitrous oxide‐oxygen with suxamethonium for intubation. The haemodynamic parameters measured were mean arterial blood pressure, central venous pressure, pulmonary artery mean pressure, pulmonary capillary wedge pressure and cardiac output. Blood volume was also measured, as were arterial blood‐gas tensions and pH. The haemodynamic changes observed during induction with intubation were significantly smaller than those observed preoperatively during exercise.
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 raie, as well as a minor decrease in stroke volume. Systemic vascular resistance decreased, but pulmonary vascular resistance remained unchanged. The response observed is discussed.