bluuebunny/crossref_metadata_2025 huggingface dataset:
Continuous Flow Apneic Ventilation
Authors: Smith R. B. , Babinski M. , Bunegin L. , Gilbert J. , Swartzman S. , Dirting J.
Published: January 2009

A study was designed to evaluate the adequacy of gas exchange during continuous flow apneic ventilation (CFAV) in dogs. Seventeen dogs (average weight 22.9 kg) were divided into three experimental groups. Group I (n = 7) was anesthetized, paralyzed and ventilated with air using intermittent positive pressure ventilation (IPPV) through a tracheal tube. The tube was removed and each main stem bronchus was cannulated with a 2.5 mm i.d., 4 mm o.d. polyethylene catheter using a fiberoptic bronchoscope. The tracheal tube was replaced to hold the catheters in place. Heated, humidified air was continuously delivered equally to each catheter. Total flows ranged from 8 to 28 1/min (0.4—1.4 1 + kg‐1 min‐‐1). Airway pressure (Paw) in the trachea did not exceed 2 mmHg (0.27 kPa). Adequate gas exchange in terms of arterial oxygen and arterial carbon dioxide tension (Pao2 and Paco2) was found after 30 min at flows greater than 16 l · min‐1. Group II (n = 7) was managed similarly to the first group, insufflating endobronchial air using the optimal flow of 1.0 1 · kg 1 · min‐1 obtained from Group I. CFAV continued for 5 h in all animals. Blood gas samples and measurements of systemic blood pressure, heart rate (HR), pulmonary artery blood pressure, pulmonary artery wedge pressure, cardiac output (Qt), and temperature were taken every 30 min. Group III (n = 3) was anesthetized similarly to the other groups. Pulmonary gas distribution was evaluated in relation to catheter placement using Xe133. Results showed significant differences between Paoj values during CFAV and IPPV; however, all animals were adequately oxygenated. During 5 h of CFAV, adequate CO2 elimination was achieved in all animals. There was no difference in PaO2, Paco2 and shunt fraction (Qs/C}t) with CFAV at 30 min and 5 h. Differences in HR, Qt, and systemic vascular resistance at 30 min and 5 h were related to the hypothermia during the developing course of experimentation. With the catheters above the carina, gas distribution studies demonstrated gas limited to the large airways with no peripheral distribution, resulting in low Pao2 levels and elevated Paco2 levels. Endobronchial catheters permitted gas distribution to the peripheral airways, and oxygenation and ventilation were normal.
Effects of Practolol and Metoprolol on QT Interval, Heart Rate and Arterial Pressure during Induction of Anaesthesia
Authors: Saarnivaara L. , Lindgren L. , Hynynen M.
Published: January 2009

The effects of the selective β1‐adrenergic receptor blocking agents, practolol with intrinsic sympathetic activity (ISA) and metoprolol without ISA, were studied on QT interval, heart rate, arterial pressure and cardiac arrhythmias during the induction of anaesthesia in 142 adults. In the control group, the QT interval was statistically significantly prolonged after thiopental, and the most marked prolongation occurred after suxamethonium. Neither practolol nor metoprolol alone affected the QT interval. Practolol 100 μg/kg i.v., but not 40 or 150 μg/kg i.v., almost completely reduced the prolongation of the QT interval after suxamethonium. In all doses of 20, 30 and 40 μg/kg i.v. metoprolol statistically significantly and dose‐dependently reduced the prolongation of the QT interval after thiopental, suxamethonium and laryngoscopy, but the prolongation of the QT interval after intubation still occurred. Practolol and metoprolol alone statistically significantly reduced heart rate, but did not prevent the increase of heart rate after thiopental. The effects on arterial pressure were minimal. Neither practolol nor metoprolol prevented the cardiovascular intubation response. Ventricular ectopic beats after intubation occurred in 20% of the patients in the control group and their incidence ranged from 20 to 27% in the groups pretreated with practolol or metoprolol 20 μg/kg. In the groups pretreated with metoprolol 30 or 40 μg/kg, ventricular ectopic beats occurred in 5% and 8%, respectively. It is concluded that the selective β1‐adrenergic receptor blocking agents practolol with ISA, and especially metoprolol without ISA, reduced the prolongation of the QT interval after suxamethonium. The results suggest that the prolongation of the QT interval after suxamethonium may be mediated by the stimulation of the sympathetic nervous system caused by suxamethonium.
Evaluation of Two Methods of Rapid Blood‐Glucose Monitoring by Unskilled Personnel during Surgery
Authors: Madsbad S. , Adelhøj B. , Bigler D. , Hilsted J.
Published: January 2009

The accuracy of two rapid methods of blood‐glucose monitoring without (Haemo‐glucotest 1—44®) and with a reflectance meter (Hypocount B®) was compared using a laboratory method. The assessment was carried out by personnel with no previous experience in measuring blood glucose. Eighty‐five percent of the 92 measurements obtained with the hypocount B were within ± 20% of the laboratory glucose values. Using haemo‐glucotest 1–44 strips, 74% of the readings were within ± 20% of the reference laboratory values. For values below 5.5 mmol/1, there was a tendency for results to be too low, with 77% of the readings below laboratory values —20%. All situations with severe hypoglycaemia were detected with both strips. The study also demonstrates the ineffectiveness of s.c. insulin regimens during surgery. Only 47% of the measured blood glucose values were within the range of 5.5–10 mmol/1 and two of ten patients had hypoglycaemia with values below 2.5 mmol/1. Therefore glucose monitoring during surgery in diabetics seems justified. This monitoring can be performed adequately with strips.
Natural Killer Cell Activity in Patients Undergoing Upper Abdominal Surgery: Relationship to the Endocrine Stress Response
Authors: Tønnesen E. , Hüttel M. S. , Christensen N. J. , Schmitz O.
Published: January 2009

Natural killer (NK) cell activity and the endocrine response during and after parietal cell vagotomy were studied in two groups of patients receiving either epidural analgesia extending from S3 to Th4 + general anaesthesia (Group I), or general anaesthesia (Group II). NK cell activity of unseparated mononuclear cells in peripheral blood was measured against K‐562 target cells in a 51Cr‐release assay. NK cell activity increased in the same way in both groups in relation to premedication, anaesthesia and surgery (P<0.01). Postoperatively, the activity fell significantly on the first day (P<0.01), but returned to preoperative levels on day 3 (Group I) and day 5 (Group II). The endocrine response measured, except for adrenaline and prolactin, differed between Group I and II. In Group I, plasma noradrenaline and serum cortisol increased insignificantly throughout the observed period ‐ compared to the preoperative level ‐ whereas a significant increase in both hormones was found in Group II during surgery and in the postoperative period. A significant increase in plasma adrenaline and serum prolactin was found in both groups during anaesthesia and surgery. The findings indicate that NK cell activity during upper abdominal surgery is modified in almost the same way during two different anaesthetic techniques, one of which partly seemed to block the endocrine surgical stress response. The fluctuations in NK cell activity were not correlated to the changes measured in hormone concentrations.
Acute Propoxyphene Self‐Poisoning in 222 Consecutive Patients
Authors: Madsen P. Sloth , Strøm J. , Reiz S. , Sørensen M. Bredgaard
Published: January 2009

The course of severe propoxyphene self‐poisoning in 222 consecutive patients is presented. On admission, 73% of the patients had neurological symptoms, 10% had convulsions, 45% were in respiratory failure, and impaired circulation was present in 48%. A mortality rate of 8% was observed. Twelve patients arrived in asystole of whom six were resuscitated without sequelae. The overdose was accidental in 13 patients, one of whom died. Early medical intensive care was found mandatory for a good prognosis. Before discharge from the ICU we recommend an observation‐period free of cardiovascular symptoms for 24 h.
Acute Self‐Poisoning with Tricyclic Antidepressants in 295 Consecutive Patients Treated in an ICU
Authors: StrøM J. , Madsen P. Sloth , Nielsen N. Nygaard , Sørensen M. Bredgaard
Published: January 2009

Clinical findings on admission to hospital and outcome in 295 consecutive patients with severe tricyclic antidepressant self‐poisoning treated in an ICU are presented. Cerebral depression was observed in 92%, convulsions in 23% and respiratory failure was present in 72%. Cardiovascular function was impaired in 44% and an abnormal ECG was found in 57%. Cardiac arrest was treated in 14 patients (6%) of whom seven were resuscitated. The mortality rate was 2%. All patients were artificially ventilated. A beneficial effect of respiratory alkalosis on cardiac arrhythmias is supported.
Effects of Enflurane on Coronary Haemodynamics in Patients with Ischaemic Heart Disease
Authors: Rydvall A. , Häggmark S. , Nyhman H. , Reiz S.
Published: January 2009

The effects of enflurane with and without nitrous oxide on coronary haemodynamics and myocardial oxygenation were investigated in 11 patients with generalised atherosclerotic disease. Enflurane decreased systemic blood pressure (‐50%) mainly by systemic vasodilation (SVR ‐41%) and to a lesser degree by impairment of cardiac performance (CO —27%). A change from 1MAC enflurane‐nitrogen‐oxygen (70/30) to 1MAC enflurane‐mtrous oxide‐oxygen (70/30) decreased blood pressure and cardiac output further (‐16% and ‐14%). Enflurane‐nitrogen‐oxygen decreased coronary blood flow (‐29%) and perfusion pressure (‐47%). Coronary vascular resistance fell (‐20%) along with decreases in myocardial oxygen consumption and extraction (— 40% and — 16%). Regional coronary blood flow measurements in four of the patients revealed maldistribution of blood flow. During enflurane‐nitrous oxide‐oxygen, myocardial oxygen consumption and extraction decreased further (‐29% and ‐12%) without change in coronary blood flow or resistance. Myocardial ischaemia was observed in four patients during enflurane‐nitrogen. During enflurane‐nitrous oxide, ischaemia disappeared in two of the previously ischaemic patients and appeared in two not previously ischaemic. The regional blood flow maldistribution was abolished with nitrous oxide. It is concluded that enflurane is a powerful coronary vasodilator and in this respect slightly less potent than isoflurane. Enflurane may induce myocardial ischaemia by redistributing coronary blood flow and/or by producing hypotension. Nitrous oxide added to enflurane depresses cardiac function and augments the coronary vasodilatory effect of enflurane to a level at which coronary blood flow becomes totally pressure dependent.
The Introduction of Ether Anaesthesia in the Nordic Countries
Authors: SECHER O.
Published: January 2009

The way in which the news about ether anaesthesia went from U. S. A. to Europe is briefly described. The first information about ether anaesthesia came to the Scandinavian countries in 1847 through newspapers, which had their information from newspapers in England, France and Germany. The professional news came to the respective countries from doctors who were studying medical progress in Paris or from French medical journals. The first Scandinavian Society to be informed was the Swedish, and the first ether anaesthesia was given in Stockholm about 6 February. Denmark was next, and the first anaesthesia was given about 20 February in Copenhagen. In Norway, ether was used on 4 March in Christiania (Oslo), and in Finland on 8 March in Helsingfors (Helsinki). Anaesthesia in Iceland cannot be traced any earlier than 1856. A table shows when the first anaesthetics were given in different places in Europe and the world.
Education for Leadership in Anaesthesiology The Sixteenth Husfeldt Lecture, Copenhagen, 11 May, 1984
Authors: PAPPER E. M.
Published: January 2009

A description of the genesis of the Anaesthesiology Centre in Copenhagen after World War II is presented. The major contribution of Professor Husfeldt in organizing is described. The need for leadrrship in anaesthesiology is discussed in detail. The characteristics of leadership and leaders are presented, and their importance in the future development of anaesthesiology is pointed out.
Sequential Myocardial Depressant and Nondepressant Anaesthesia for Coronary Artery Surgery
Authors: SETTERGREN G. , ÖHQVIST G. , EKESTRÖM S.
Published: January 2009

Patients undergoing coronary artery surgery run a certain risk of developing myocardial infarction in situations with increased myocardial oxygen demand due to e. g. elevations in heart rate and blood pressure. After cardiopulmonary bypass (CPB) there is, however, also the risk of graft occlusion. The present study evaluated the haemodynamic effects of a sequential anaesthesiological technique using halothane 0.5‐1.5% in combination with 50% nitrous oxide and droperidol 0.1 mg ⋅ kg b. w.‐1 before CPB followed by fentanyl 0.2 mg ⋅ h‐1 in continuous i. v. infusion and diazepam 10–15 mg during and after bypass. Fourteen patients were studied. In seven patients (Group I) halothane was discontinued immediately before CPB and in the following seven patients (Group II) 10–15 min before bypass. The aim was to depress moderately the inotropic state before bypass and to have a normalized myocardial oxygen demand after CPB in order to promote a good flow in the grafts. In Group II mean left ventricular stroke work index (LVSWI) was 0.54‐0.79 J ⋅ m‐2 after bypass as compared to 0.45‐0.51 before at comparable filling pressure. Mean left ventricular power index (LVPI) increased from 0.42‐0.55 W ⋅ m‐2 before to 0.73‐1.08 after CPB. The patients in Group I showed a similar pattern although with a less marked difference in LVSWI and LVPI values before and after bypass. No correlation was seen between oxygen delivery and oxygen uptake either below or above an oxygen delivery of 15 mmol ⋅ min‐1 ⋅ m‐2.
Differential Effects of Epidural Morphine in the Treatment of Cancer‐related Pain
Authors: ARNÉR S. , ARNÉR B.
Published: January 2009

Fifty‐five patients with pain associated with cancer were selected for long‐term treatment with epidural morphine. Patients who had more than one type of pain within the same region were specially analysed concerning differential analgesic effects of the treatment, i. e. the patients served as their own control. Twenty‐eight of the 55 patients became pain free. In 21 patients alleviation of pain was complete only for one or two of several types of pain within the same area with a certain dose of epidural morphine. In six patients the treatment failed. An analysis revealed that the best response was obtained when the pain was continuous and originated from deep somatic structures. In co‐existing continuous visceral pain or intermittent somatic pain originating e. g. from a pathological fracture, the outcome of the treatment was variable. Cutaneous pain, pain classified as neurogenic, and intermittent pain due to intestinal obstruction was only occasionally relieved. Ten of the patients had co‐existing pain of non‐malignant origin and none of them was helped for that pain. The variable response to epidural morphine may indicate that different types of pain‐producing stimuli engage different kinds of receptors which differ in affinity to morphine in the spinal fluid; it is also possible that some pain‐mediating systems are non‐responsive to opiates.
Effects of Prenalterol and Volume Loading with Dextran on Haemodynamics and Oxygen Consumption in Dogs During High Epidural Block with Special Reference to the Splanchnic Region
Authors: GREITZ T. , ANDREEN M. , IRESTEDT L.
Published: January 2009

High lumbar epidural block was induced in seven dogs, causing a fall in mean arterial blood pressure (AP) from 24.5 ⋅ 2.9 to 12.0 ⋅ 3.1 kPa owing to reductions in cardiac output (QT) and systemic vascular resistance (SVR) to 67% and 68% of the pre‐epidural values. Volume loading with dextran 10 ml ⋅ kg‐1b. w. increased QTnearly to the pre‐epidural value. SVR decreased further to 61% of the pre‐epidural value and AP was only slightly increased to 14.9 ⋅ 2.7 kPa. Subsequent administration of prenalterol 20 μg ⋅ kg‐1b. w. caused a further increase in QTto 17% above the pre‐epidural value due to an increase in heart rate of 51 beats/min. AP did not change since SVR decreased further to 49% of the pre‐epidural value. The hepatic arterial blood flow (QHA) was essentially unchanged during epidural block as well as during volume loading, while the portal venous blood flow (QPV) was changed concurrently with (QT). In spite of the decrease in SVR, the preportal and hepatic arterial vascular resistances were not diminished following prenalterol. The increase in QTmust therefore have favoured other vascular beds. Hepatic and pre‐portal tissue oxygen uptakes were unchanged during the experimental procedure, while whole‐body oxygen uptake decreased by 20% following the epidural block and increased nearly to the pre‐epidural level following volume loading in combination with prenalterol.
Renin Release during Controlled Hypotension with Sodium Nitroprusside, Nitroglycerin and Adenosine: A Comparative Study in the Dog
Authors: LAGERKRANSER M. , SOLLEVI A. , IRESTEDT L. , TIDGREN B. , ANDREEN M.
Published: January 2009

The haemodynamic effects of i. v. infusions of sodium nitroprusside (SNP), nitroglycerin (TNG), and adenosine were studied in dogs in parallel with quantitative determinations of plasma renin activity (PRA) by radioimmunoassay. The drugs were given for controlled hypotension, and the mean arterial blood pressure (MABP) was decreased to approximately 50 mmHg (6.7 kPa). Arterial blood samples for PRA were collected at 10‐min intervals. During the last interval the dogs were subjected to haemorrhagic shock. SNP‐induced hypotension could be maintained only with a stepwise increase in infusion rate, from 11.8 to 16.0 μg ⋅ kg‐1 ⋅ min‐1 (P<0.05). TNG could not produce the desired blood pressure level, but gradually increasing doses induced a gradually decreasing MABP (80‐60 mmHg) (10.7–8.0 kPa). During adenosine‐induced hypotension, a perfectly stable blood pressure level was maintained without dose adjustments. Both SNP and TNG induced blood pressure‐dependent increases in PRA, while no changes in PRA were seen during adenosine‐induced hypotension. Nor could haemorrhagic shock, which induced further increases in PRA during SNP‐ and TNG‐induced hypotension, alter PRA during adenosine infusions. We conclude that adenosine differs markedly from conventional hypotensive drugs such as SNP and TNG with respect to stability of action and dose requirements, and that this stability is related to an inhibited increase in renin release.
Effect of Anaesthesia on Respiratory Function after Major Lower Extremity Surgery A Comparison between Bupivacaine Spinal Analgesia with Low‐Dose Morphine and General Anaesthesia
Authors: HEDENSTIERNA G. , LÖFSTRÖM J.
Published: January 2009

Postoperative pulmonary function was studied in 16 patients undergoing total hip or knee arthroplasty. Their mean age was 65 years. Half of them received spinal analgesia (22.5 mg bupivacaine+ 0.3 mg morphine) and the other half underwent general anaesthesia with halothane‐nitrous oxide. Four hours postoperatively, the forced expirogram was maintained in the spinal analgesia group, compared with preanaesthesia measurements. Functional residual capacity (FRC) measured by multiple breath nitrogen washout was reduced by 0.5 1, as was closing capacity (CC) measured by the bolus technique. The gas distribution index (nitrogen washout delay) was unaltered. The alveolar‐arterial oxygen tension difference (PA‐ao2) was not significantly altered, but arterial oxygen tension (Pao2) was reduced by 1.7 kPa, and arterial carbon dioxide tension (Paco2) was increased. No respiratory measurements could be made in the general anaesthesia group 4 h postoperatively, but arterial blood gases were unaltered compared with preanaesthesia values. Eighteen hours postoperatively, forced vital capacity (FVC) was reduced in the spinal analgesia group, FRC and CC remained diminished and the gas distribution index was increased, indicating less efficient gas mixing. Simultaneously, PA‐ao2 was increased, and Pao2 remained reduced despite increased alveolar ventilation (lowered Paco2). In the general anaesthesia group FVC, FRC and CC were also reduced, but the gas distribution index remained at the awake level and blood gases were unaltered. It is suggested that the slight hypoventilation in the spinal analgesia group early after surgery may have contributed to impaired gas distribution and ventilation‐perfusion matching later postoperatively.
Development and Evaluation of a Flow‐Dividing Unit for Differential Ventilation and Selective PEEP
Authors: DAROWSKI M. , HEDENSTIERNA G. , BAEHRENDTZ S.
Published: January 2009

Differential ventilation with selective positive end‐expiratory pressure (PEEP) was studied in a two‐compartment lung model, using one ventilator and a flow‐dividing unit consisting of inspiratory flow resistors and an inspiratory threshold valve. The compliance of each lung compartment was varied between 0.15 and 0.23 1 ⋅ kPa‐1 and the resistance was varied from 0 to 3.5 kPa ⋅ 1‐1 ⋅ s. The minute volume was 12 1 and the respiratory frequency 12/min, with an inspiratory:expiratory ratio of 1:2. An even distribution of ventilation to the two lung compartments was obtained with the inspiratory flow resistors or the threshold valve under all conditions studied. However, a stepwise increase in the inspiratory resistance of one lung compartment from 1.0 to 2.5 or from 2.5 to 3.5 kPa ⋅ 1‐1 ⋅ s required readjustment of the inspiratory flow resistor to achieve an even distribution of ventilation, whereas the inspiratory threshold valve needed no readjustment. Large differences in the inspiratory impedance of the two lung compartments caused asynchronous gas delivery when the ventilation distribution was adjusted by means of the flow resistors. Use of the threshold valve resulted in synchronous gas delivery. The flow‐dividing unit consists of non‐active elements and can thus be connected to any ventilator.
Skin Conductance Responses During Spinal Analgesia
Authors: BENGTSSON M. , LÖFSTRÖM J. B. , MALMQVIST L. ‐A.
Published: January 2009

Skin conductance responses (SCR, “sympatho‐galvanic reflex”) were measured before and during spinal analgesia in 17 patients scheduled for transurethral surgery. Responses were provoked by standardized electrical stimulation over the clavicle opposite to the recording side; alternatively, a short deep breath, pinching, verbal stimuli or sharp sounds were used. Measuring sites (two electrodes 6 cm apart) were the hand, levels T5, T9, T12‐L1 and the foot. Spinal analgesia reached a median cephalad level of T4 (mean T4, range ⋅ 3 segments) 20–25 min after injection. SCR was markedly depressed in the foot in 15 of 17 patients, at T12‐L1 in 12 of 17, at T5 in 10 of 17, at T5 in 9 of 16 and in the hand in 6 of 17. Total abolition of the SCR in the foot was accomplished in only seven cases and sympathetic activity reappeared long before regression of analgesia or motor blockade was observed. In four cases of five with an analgesic level T1‐T2, the SCR was preserved in the hand. No consistent correlation between blood pressure change and SCR‐change was seen. The conclusion from this study is that preganglionic sympathetic B‐fibres are more difficult to block than A‐fibres during spinal analgesia. The duration of sympathetic blockade was far shorter than analgesia and motor blockade. Thus, sympathetic blockade during spinal analgesia seems to be far less extensive than that described in the literature.
A New Method for Measuring Motor Block in the Lower Extremities
Authors: AXELSSON K. , HALLGREN S. , WIDMAN B. , JOHANSSON A. , OLSTRIN P.‐O.
Published: January 2009

A method for determining muscle strength in the lower extremities was developed and its clinical application evaluated in ten elderly, healthy subjects, and also subsequently in one of them during spinal anaesthesia. With the subject lying in the lithotomy position on a modified operating table, muscle strength measurements were made during flexion of the hip, extension of the knee and plantar flexion of the big toe. The electromechanical performance of the apparatus was stable, and the maximum measurement errors observed at loads of 245 and 49 N were 4 and 11% of the deflections, respectively. The subjects underwent repeated muscle strength measurements during a 4‐h period without any difficulty. No signs of muscular fatigue were observed. The variation of the measured isometric muscle strength was small and the average coefficient of variation roughly 10%. In the patient receiving spinal anaesthesia, the degree of motor block was determined, and the results are presented graphically. This new method for evaluation of motor block in the lower extremities is a reliable quantitative method for bilateral, three‐joint muscle strength measurements, which is also applicable during regional anaesthesia.
Cardiovascular Studies during Controlled Baroreflex Activation in the Dog: II. Effects of Metoprolol and Enflurane
Authors: HENRIKSSON B. ‐Å. , BIBER B. , LUNDBERG D. , MARTNER J. , PONTÉN J.
Published: January 2009

An experimental model was designed to study circulatory drug effects with or without barostatic reflex influences. In dogs anaesthetized with chloralose, both carotid sinuses were perfused from a femoral by‐pass either with systemic arterial pressure or with a pump in order to control the sinus pressure. Cardiac and aortic baroreceptors were denervated. I. v. metoprolol (240 μg ⋅ kg‐1+ 102 μg ⋅ kg‐1⋅ h‐1) with constant carotid sinus pressure and thereby constant baroreceptor activation reduced cardiac output, heart rate, cardiac contractility and left ventricular stroke work index. Systemic vascular resistance increased. This response was independent of the degree of baroreflex activation. During the combined administration of enflurane (1.6% end‐tidal concentration) and metoprolol, cardiac performance (cardiac output, stroke volume, heart rate, cardiac contractility and left ventricular stroke work index) was depressed independent of the degree of baroreflex activation. Barostatic reflexes, however, counteracted an observed decrease in systemic vascular resistance. This reflex vascular response was, during metoprolol‐enflurane administration, associated with an increased left ventricular end‐diastolic pressure.
Apneic Diffusion Oxygenation and Continuous Flow Apneic Ventilation. A Review
Authors: SMITH R. B. , SJÖSTRAND U. H.
Published: January 2009

Evolution of life coincides with the most rapid rate of rise in atmospheric oxygen concentration during Devonian time. Oxygen is essential for life, but at the same time is a cellular poison if present in tensions considerably higher than those the particular cellular milieu has become adapted to. Animals exposed to low oxygen tensions breathe continuously, e. g. most species of fish obtain their oxygen from a continuous flow of water at low oxygen tensions. Evolution from water to land breathing generally is associated with intermittent breathing, mass movement of gas in one direction, i. e. inhalation and exhalation. Intermittent breathing is part of this evolutionary process and reduces the inspired oxygen tension from 150 mmHg (19.95 kPa) to approximately 100 mmHg (13.3 kPa) at the alveolar blood interface. Perhaps evolution from continuous ventilation to intermittent breathing may be protecting the body against the high atmospheric oxygen tension. Therefore, it is not surprising that mammals can have adequate oxygen uptake with apneic diffusion oxygenation (ADO) and continuous flow apneic ventilation (CFAV). Mechanical ventilation classic techniques, i. e. intermittent positive‐pressure ventilation and continuous positive‐pressure ventilation, employ ventilatory frequencies close to the resting breathing rate of the adult. Utilizing low‐compression patient circuits has made mechanical ventilation with higher frequencies possible. 60 to 400 breaths per min is used for high‐frequency positive‐pressure ventilation and high‐frequency jet ventilation, and up to 40 Hz is used for high‐frequency oscillation (HFO). The two extremes of artificial ventilation ‐ ADO, i. e. supply of O2 by continuous flow, and HFO, i. e. supply of O2 by oscillatory changes ‐ both primarily involve diffusion, even though convection (also secondary to cardiac oscillations) obviously is important in the process of gas exchange. Some recent experimental findings favor continued development and evaluation of CFAV as an additional alternative to artificial ventilation.
A Method for Epiduroscopy and Spinaloscopy Presentation of Preliminary Results
Authors: BLOMBERG R.
Published: January 2009

A method for endoscopic observation of the epidural space, epiduroscopy, and the subarachnoid space, spinaloscopy, in the lumbar region is described using the Olympus Selfoscope SES 1711 S. The preliminary results of 30 consecutive attempts at epiduroscopy on randomly chosen autopsy cases, with 28 successes, are presented. Five spinaloscopies were performed on the same material. The results justify the conclusion that epiduroscopy and spinaloscopy are methods that can be used for study of individual variation of the contents of the lumbar epidural and subarachnoid spaces.
Efficacy of the Ejector Flow‐meter. A Scavenging Device for Anaesthetic Gases
Authors: OBEL D. , JØRGENSEN S. , FERGUSON A. , FRANDSEN K.
Published: January 2009

Measurements of air concentrations of nitrous oxide and halothane in the breathing zone of the anaesthetist and the operating‐room nurse were carried out during inhalation anaesthesia with a Mapleson D system. Gas removal was performed from inside the breathing system at the same rate as that of the fresh gas inflow by means of an ejector flow‐meter. The concentrations of nitrous oxide and halothane were maintained below the Danish Threshold Limit Values of 100 and 5 parts per million, respectively, by using this type of scavenging. When these anaesthetics were used simultaneously, the reduced Threshold Limit Values were not exceeded during endotracheal anaesthesia.
Circulatory Shock Following Intravenous Propoxyphene Poisoning. An Experimental Study of Cardiac Function and Metabolism in Pentobarbital‐Anesthetized Pigs
Authors: SØRENSEN M. BREDGAARD , HÄGGMARK S. , NYHMAN H. , MADSEN P. SLOTH , STRØM J. , REIZ S.
Published: January 2009

The effects of continuously administered intravenous propoxyphene chloride (15 mg⋅min‐1) on ECG, systemic, pulmonary and coronary circulations and myocardial oxygenation were investigated in eight pentobarbital‐anesthetized pigs. Circulatory shock, defined as a systolic blood pressure below 60 mmHg (8.0 kPa) and a cardiac output of approximately 2.0 1 ⋅ min‐1⋅ m‐2, occurred after 675 to 2025 mg propoxyphene chloride. At the time when shock occurred plasma concentrations of propoxyphene ranged from 9.6 to 15.3 μg‐ml‐1which is within the range of the lethal concentration observed in man. Statistically significant decreases were observed for the following variables: maximum rate of rise of left ventricular pressure dP/dt (–90%), mean arterial pressure (– 73%), heart rate (– 46%), cardiac index (– 58%), stroke volume index (–22%), left ventricular stroke work index (–85%), right ventricular stroke work index (–63%) and systemic vascular resistance (– 50%). Mean pulmonary arteriolar occlusion pressure increased (+ 42%), whereas mean right atrial pressure and pulmonary vascular resistance remained unchanged. The arteriovenous oxygen difference increased (+ 53%) and total body oxygen consumption decreased (–35%). The following coronary variables decreased: coronary sinus blood flow (– 57%), coronary vascular resistance (– 65%), myocardial oxygen consumption (– 68%), myocardial oxygen extraction (– 26%) and myocardial lactate extraction (– 28%). Prolongation of the ECG PQ and QRS intervals were recorded shortly before shock appeared, and all animals were in sinus rhythm till the last minute before death. The results indicate that intravenously administered propoxyphene besides being a powerful negative inotropic and chronotropic agent, is also a potent systemic and coronary vasodilator.
Haemodynamic Response to Nitrous Oxide during High‐Dose Fentanyl Pancuronium Anaesthesia
Authors: MERETOJA O. A. , TAKKUNEN O. , HEIKKILÄ H. , WEGELIUS U.
Published: January 2009

Ten patients subjected to coronary by‐pass surgery were studied to determine the haemodynamic effects of replacing Fio2 1.0 normoventilation with nitrous oxide in oxygen (Fio2 0.3) after induction of anaesthesia with fentanyl (50 μg/kg), flunitrazepam and pancuronium. In all patients the application of N2O decreased systemic arterial pressures by an average of 10% (P<0.001), but left pulmonary arterial pressures and systemic vascular resistance unchanged. The slight bradycardia induced was associated with moderate depression of the cardiac index and the left ventricular stroke work index (P<0.001) at the time when the rate‐pressure product was decreased by 20% (P<0.001). The cardiac depression produced by N2O was most prominent in patients with left ventricular wall hypokinesia and an ejection fraction below 55%, in whom the cardiac work index was diminished by 29%. The replacement of oxygen with nitrous oxide in oxygen during high‐dose fentanyl‐pancuronium anaesthesia seems not to be associated with sympathetic stimulation, and the myocardial depressant effect of N2O should be weighed against the possible reduction in myocardial oxygen consumption with special care in patients with compromised myocardial function.
Epidural Morphine for Postoperative Pain: Experience with 1085 Patients
Authors: STENSETH K. , SELLEVOLD O. , BREIVIK H.
Published: January 2009

A prospective study of the effect and side‐effects of epidural morphine for pain relief in 1085 patients after thoracic, abdominal, urologic, or orthopaedic surgery was performed. Morphine chloride was diluted in saline or bupivacaine and administered through an epidural catheter placed at a segmental level appropriate for the type of surgery. The initial dose was 4 or 6 mg morphine and supplementary doses were given when needed to obtain complete freedom from pain during deep breathing or nursing care. The total dose of epidural morphine from end of surgery until the next morning varied from 4 to 18 mg. 97% of hip arthroplasty patients, 91% of prostatectomy patients and thoracotomy patients, 90% of patients after major lower extremity surgery and 88% of patients after laparotomy were completely satisfied with the postoperativr course. For hip arthroplasty and major extremity surgery, an initial dose of 4 mg of epidural morphine was as effective as 6 mg. After prostatectomy, laparotomy, and thoracotomy, an initial dose of 6 mg gave significantly better effect than 4 mg. Pruritus occurred in 11%, nausea or vomiting in 34%, and respiratory depression in 0.9% of the total patient population. Urinary retention occurred in 42% of patients not having urinary catheters in place. Postoperative nausea or vomiting was more frrquent in women than in men (P<0.001). There was a higher incidence of nausea or vomiting in men experiencing pain than in men who were completely pain‐free after abdominal surgery (P<0.001). Respiratory depression was rare and occurred as a gradually decreasing respiratory rate. Treatment with naloxone was effective without pain‐breakthrough. Naloxone relieved pruritus in 9O% of patients in whom it was attempted, but was not effective in treating nausea, vomiting, or urinary retention. After this study our dosage regimen for postoperative epidural morphine is: for major surgery of the lower limb or hip arthroplasty 4 mg; after prostatectomy. laparotomy, and thoracotomy 6 mg. No later than 12 h before the patients leave the postoperative care unit, half the initial dose of epidural morphine is usually repeated. Morphine is diluted in bupivacaine if pain is already present, otherwise in saline.
Influence of Two Different Anaesthetic Agents on the Newborn and the Correlation between Foetal Oxygenation and Induction‐Delivery Time in Elective Caesarean Section
Authors: BERNSTEIN K. , GISSELSSON L. , JACOBSSON L. , OHRLANDER S.
Published: January 2009

The Po2 and acid‐base balance (pH, Pco2 and base deficit) of the newborn, determined at the moment of birth and at 10 and 60 min after birth, were compared in two series of elective caesarean section, anaesthesia being induced with thiopentone in one series (n= 12), and with ketamine in the other (n= 16). The Po2 and acid base values of umbilical cord blood at birth were correlated with the induction delivery (ID) times of the total series of patients subjected to elective caesarean section (n = 28). The ID‐times were varied between 2 and 10 min. The Po2, acid‐base values and Apgar scores did not differ between the thiopentone and ketamine groups. A significant negative correlation between the Po2 of the newborn at the moment of birth and the ID‐time was found in the thiopentone group. The study suggests that ketamine is a good alternative to barbiturate as an induction agent for caesarean section.
Maternal Haemodynamic Changes during Caesarean Section: A Comparison of Epidural and General Anaesthesia
Authors: MILSOM I. , FORSSMAN L. , BIBER B. , DOTTORI O. , RYDGREN B. , SIVERTSSON R.
Published: January 2009

Haemodynamic measurements were performed on 20 healthy women before and during elective caesarean section under epidural (10 women) or general anaesthesia (10 women). The influence of the two anaesthetic techniques on the haemodynamic changes associated with operative delivery was compared. The following haemodynamic variables were studied: cardiac output (CO), stroke volume (SV) determined non‐invasively with impedance cardiography, heart rate (HR), systolic (SBP) and diastolic blood pressure (DBP), pulse pressure, mean arterial pressure (MAP) and total peripheral vascular resistance (TPR). During epidural anaesthesia, SV was largely unchanged before delivery but increased (P<0.05) following delivery. However, CO increased (P<0.05) prior to delivery due to an increase (P<0.01) in HR. A further increase (P<0.05) in CO was recorded following delivery. SBP, DBP, MAP and TPR decreased (P<0.01) during epidural anaesthesia. In the patients undergoing general anaesthesia, SV decreased (P<0.05) prior to delivery. However, CO remained largely unchanged due to an increase (P<0.01) in HR. Following delivery, CO (P<0.05) and SV (P<0.01) increased whereas HR decreased (P<0.01). SBP, DBP and MAP increased (P<0.01) prior to delivery, returning to the same level as prior to induction of anaesthesia following delivery. TPR was largely unchanged prior to delivery but decreased (P<0.01) following delivery.
Caudal or Dorsal Nerve Block?
Authors: VATER M. , WANDLESS J.
Published: January 2009

Fifty boys presenting for day case circumcision were allocated randomly to receive either caudal analgesia or dorsal nerve block (DNB) to provide postoperative pain relief. Analgesia was assessed by a single, unbiased observer utilising a three‐point scale. Subsequently, parents completed a simple questionnaire. Subjects in the DNB group micturated earlier (P<0.05) and stood unaided earlier (P<0.025) than patients in the caudal group. The incidence of vomiting was significantly lower in the DNB group (P<0.05). There was no significant difference in the duration of analgesia, although that produced in the DNB group tended to wane sooner. It is concluded that DNB provides satisfactory analgesia following circumcision and has specific advantages when compared with caudal analgesia.
Effect of Postoperative Extradural Morphine on Lower Urinary Tract Function
Authors: HUSTED S. , DJURHUUS J. C. , HUSEGAARD H. C. , JEPSEN J. , MORTENSEN J.
Published: January 2009

The effect of postoperative extradurally administered morphine on lower urinary tract function was studied in female patients undergoing uterine surgery. Urodynamic measurements were made on the day before and on the day after the operation, using a DISA 2‐channel carbon dioxide (CO2) cystomictrograph. In ten patients without postoperative urinary retention no changes in cystometry were found during morphine administration, while two patients who developed acute urinary retention had a marked increase in bladder capacity and of detrusor pressure. In contrast, the urethral pressure profile was unchanged in both groups of patients. Intravenously administered naloxone tended to normalize the bladder capacity in the patients with urinary retention. These findings seem to indicate a marked effect in some patients of extradurally administered morphine and the acute urinary retention, following morphine administration, may be treated with naloxone.
Postoperative Respiratory Complications in Non‐Idiopathic Scoliosis
Authors: ANDERSON P. R. , PUNO M. R. , LOVELL S. L. , SWAYZE C. R.
Published: January 2009

The medical records of 303 patients undergoing fusions for scoliosis correction were retrospectively reviewed. The frequency and type of postoperative respiratory complications were compared in idiopathic versus non‐idiopathic scoliosis patients in relation to age, type of spinal fusion procedure, pulmonary function test (PFT) results and preoperative diagnoses. The following factors were found to increase the incidence of problems in the postoperative period: a non‐idiopathic type of scoliosis, mental retardation, anterior spinal fusion procedures, age of 20 or more years, a relative arterial hypoxemia and an obstructive component to the PFT's. Topics for further investigation are suggested.
Analysis of 13800 Subclavian Vein Catheterizations
Authors: EEROLA R. , KAUKINEN L. , KAUKINEN S.
Published: January 2009

During the period 1974–1983, 13857 subclavian or internal jugular vein catheterizations were analysed in the same hospital. The data on the catheterizations have been collected prospectively in the hospital computer. In 93% of the cases, catheterization was subclavian vein cannulation performed through the infraclavicular route. In 15% of the cases the catheter position was not ideal, verified with x‐ray; e. g. the catheter tip was turned into the internal jugular vein. Of the catheters 70% were kept in place for less than 7 days, and only 6% for over 2 weeks. More than one catheterization was required in 26% of the cases during the same hospitalization. Recatheterization is an important prophylactic measure for preventing septic complications, if suspicion of infection arises. In 5% of the cases, some complications occurred, but they were mostly minor, such as haematoma at the puncture site. More serious complications were 19 pneumothoraces (0.1%). The results suggest that subclavian vein catheterization is a fairly safe method for large‐scale use in a hospital, if only a limited group of physicians perform it. Certain precautions should, however, be taken.
Relationship between Arterial and Heated Skin Surface Carbon Dioxide Tension in Adults
Authors: JACOBSEN E. , GØOSTHGEN I.
Published: January 2009

Carbon dioxide tension was measured on heated skin surface (PSCO2) and in arterial blood (PaCO2) in eight adult patients during intermittent positive pressure ventilation. A total of 299 PaCO2 ‐ PSCO2 measurements were performed at electrode temperatures of 45°C, 43°C and 38°C. The PSCO2‐PaCO2 relation was evaluated using: 1) linear regression, 2) PSCO2/PaCO2 ratio and 3) temperature correction methods. Both linear regression and ratio indicate temperature dependency of the PSCO2‐PaCO2 relation. The temperature correction method was done with a blood PCO2 temperature coefficient of 4.6% per °C and at two temperatures: electrode temperature (according to Severinghaus) and estimated capillary blood temperature. The results indicate that the relation between PaCO2, PSCO2 and electrode temperature is constant enough to permit estimation of PaCO2 from PSCO2 during stable circulatory conditions.
Nitrous Oxide Exposure during Routine Anaesthetic Work
Authors: SONANDER H. , STENQVIST O. , NILSSON K.
Published: January 2009

Nitrous oxide exposure in a modern hospital during routine anaesthetic work was measured using a technical exposure measurement technique and compared to measurement of biologic exposure from urine samples. The study included different anaesthetic situations and also a study of the efficiency of close scavenging and general air‐conditioning in reducing nitrous oxide exposure. Exposure to nitrous oxide varied greatly. The mean nitrous oxide exposure in the total material was 53 ppm corresponding to approximately half the Swedish control limit (100 ppm) for 8 h time‐weighted avarage (TWA). The only anaesthetic situation regularly resulting in 8 h TWA exposure exceeding the control limit was paediatric anaesthesia (92 ± 67 ppm, mean ± s. d.). The use of close scavenging significantly reduced the 8 h TWA nitrous oxide exposure in paediatric anaesthesia. The reduction of exposure was not significant during other forms of anaesthesia where low levels were found when anaesthetic equipment with excess gas scavenging was used in theatres with non‐recirculating air‐conditioning. The correlation between conventional technical exposure measurement and urine headspace nitrous oxide measurement was good. Both theoretical arguments and practical experience indicate that this method can be used for assessing nitrous oxide exposure during routine anaesthetic work.
Naloxone Does Not Reverse the Pain‐Reducing Effect of Vibratory Stimulation
Authors: LUNDEBERG T.
Published: January 2009

Fifteen patients suffering from chronic epicondylitis pain who obtained alleviation of pain with vibratory stimulation were studied to investigate the possible role of endogenous opioids in the mediation of pain alleviation of vibratory stimulation. The patients' subjective pain intensity was rated using a graphic rating scale. In five patients the changes in peripheral blood flow before, during and after vibratory stimulation were also studied. After 30 min of mechanical vibratory stimulation at 100 Hz, patients were given a doubleblind intravenous injection of naloxone or saline (placebo). Twelve patients did not experience reversal of pain relief from naloxone (0.4 mg). Reversal of the pain alleviation induced by vibratory stimulation was seen in two patients after i. v. injections of naloxone and in one patient after i. v. injections of naloxone or saline. When an i. m. injection of naloxone 0.01 mg/kg was administered before and during vibratory stimulation, none of the patients experienced an antagonistic effect of the pain‐reducing effect of vibratory stimulation. The results suggest that the pain relief obtained with vibratory stimulation at 100 Hz is not associated with release of endogenous opioids.