bluuebunny/crossref_metadata_2025 huggingface dataset:
Do Nitrous Oxide and Lidocaine Modify the BloodBrain Barrier in Acute Hypertension in the Rat?
Authors: Johansson B. B. , Linder L. E.
Published: January 2009

Acute hypertension was induced by adrenaline or bicuculline in rats mechanically ventilated with 70% nitrous oxide in oxygen, in unrestrained rats breathing the same gas mixture, and in conscious unrestrained rats breathing air. The unrestrained rats had permanent indwelling catheters in the aorta and in one jugular vein. Three minutes after the pressure rise the rats were killed and the brains perfused in situ with saline. The protein leakage into the brain was studied with Evans blue‐albumin and 125IHSA (human serum albumin). The extravasation of ?HSA in unrestrained rats breathing nitrous oxide was higher than in rats breathing air after injection of bicuculline, but the difference was not statistically significant. Lidocaine significantly decreased the protein leakage in both conscious and anaesthetized rats. It is concluded that not only the vascular tone but also endothelial cell membrane properties can influence the hypertensive blood‐brain barrier dysfunction.
Sympathetic Nervous System Tonicity and Post‐Coronary Artery Bypass Hypertension
Authors: Pratilas V. , Pratija M. G. , Vlachakis N. D. , Owitz S. , Dimich I.
Published: January 2009

To elucidate the pathogenesis of hypertension following coronary bypass surgery, blood pressure and plasma catecholamine concentration were measured in 28 patients with coronary artery disease who were undergoing myocardial revascularizat ion procedures. Measurements were obtained on arrival in the operating room and 1 and 4 h after surgery.

One hour after surgery, plasma norepinephrine (NE) increased significantly by 495k 108 pg/ml (P<0.001) in the coronary artery disease group which developed hypertension, but the increase was not significant in the coronary artery patients who remained normotensive after surgery. However, 4 h after surgery, plasma NE increased significantly and to the same extent in both coronary artery disease groups, regardless of the change in blood pressure.

Plasma epinephrine (E) also increased significantly 1 and 4 h after surgery in both groups. The observed change in plasma catecholamine concentration is direct evidence that the stress of surgery is a potent adrenergic stimulus, but the hemodynamic significance of the plasma catecholamine change remains unclear.
Effects of Nitrous Oxide oa S)stolic Time Intervals
Authors: Eriksen S. , Johannsen G. , Frost N.
Published: January 2009

The elrects of inhalation of oxygen, nitrous oxide/oxygen and nitrous oxide/nitrogen/oxygen on systolic time intervals (PEP (pre‐ejection period) and LVET (left ventricular ejection time)) were investigated in eight healthy persons. Nitrous oxide 40%, administered with oxygen or oxygen /nitrogen, prolonged PEP significantly by 25% and 22%, respectively. Inhalation of oxygen also prolonged PEP but to a significantly minor degree.

LVET, heart rate and MAP were unchanged during the experiments. Derivatives from the systolic time intervals, i.e. PEP/LVET, I/PEP2 and ejection fraction changed significantly in the nitrous oxide groups. It is concluded that nitrous oxide depresses cardiac performance, to some degree, even when administered at a rather low concentration.
Pain Relief and Sputum Prostaglandins in Adults Treated with Pethidine, Tilidine and Indomethacin After Tonsillectomy: A Double‐Blind Study
Authors: Saarnivaara L. , Metsä‐Ketelä T. , Männistö P. , Vapaatalo H.
Published: January 2009

1Otolaryngological Hospital, University of Helsinki. Helsinki, and Department of Biomedical Sciences, University of Tampere, Tampere. Finland.

The pain‐relieving effects of pethidine (1 mg/kg i.m.), tilidine (2.5 mg/kg i.m.) and indomethacin (100 mg rectally) were investigated in 87 voluntary adult patients after tonsillectomy in a double‐blind study. All the drugs relieved pain equally. The maximal emerr appeared 60–75 min after drugadministration, and lasted until the end of the 120‐min observation period. Bleeding from the operative site w'as the most common side effect. It appeared in 28, 24 and 3% of the patients treated with indomethacin, tilidine and pethidine, respectively. Two patients in the indomethacin group and one patient in the tilidine group needed a suture for stopping the bleeding, whereas the bleeding in the pethidine group stopped without any special treatment. Further side effects were headache, dizziness, nausea and vomiting. Their incidence ranged from 0 to 17% in various groups.

On the evening of the operative day, the indomethacin patients received another dose of indomethacin, whereas the other patients received a plarebo suppository. On the following morning, the pain score was lowest and the speech least impaired in the indomethacin patients. After indomethacin, the axillary temperature remained below 37oC, whereas it was slightly elevated in the other groups. In all groups the blood leucocyte count was significantly increased. The control values for the excretion of prostaglandin F., in sputum ranged from 2.9 to 3.9 ng/8 min. The values were increased by 233, 183 and 29% in pethidine, tilidine and indomethacin group, respectively. The control values for prostaglandin E ranged from 1.5 to I.9 ng/8 min. There was an increase of 205, 111, and 80% in the pethidine, tilidine and indomethacin group, respectively.

The results suggest that. of the drugs studied, pethidine is most convenient for treatment of throat pain immediately after tonsillectomy in adults. During the later postoperative period, indornethacin may be used for alleviation of pain and inflammatory responses.
A Comparison Between Reaction Time Measurement and Critical Flicker Fusion Frequency Under Rising Nitrous Oxide Inhalation in Healthy Subjects
Authors: Wernberg M. , Nielsen S. F. , Hommelgaard P.
Published: January 2009

Ten subjects volunteered to inhale a test gas containing 0, 10, 20 and 30% nitrous oxide. After equilibration at each nitrous oxide concentration, the reaction time was measured using both the single‐hand and the double‐hand methods, and then the critical flicker fusion frequency was measured. Using the flicker fusion frequency test, significant changes from the normal range were found at 20 and 30% nitrous oxide in the test gas, whereas no significant changes were found with the fusion flicker frequency test. No significant prolongation was found with either double‐hand or single‐hand reaction time measurements until 30% nitrous oxide in the test gas was reached.

It is concluded that critical flicker fusion frequency measurement is a simpler, more time‐saving and more sensitive method for the estimation of the changes which nitrous oxide produces in healthy subjects than reaction time measurement, and that critical flicker fusion frequency measurement will presumably be a useful supplement to clinical examination as an objective method for the estimation of postanaesthetic recovery in patients.
Laryngeal Oedema as an Obstetric Anaesthesia Complication: Case Reports
Authors: Jouppila R. , Jouppila P. , Hollmén A.
Published: January 2009

Three cases of laryngeal oedema leading to endotracheal intubation dificulties in obstetric anaesthesia are described. The first case occurred immediately postpartum in a patient who developed a swollen face from strenuous bearing down efforts in the second stage of labour. The other two cases were patients with severe pre‐eclampsia including marked generalized oedema. The possibility of the occurrence of laryngeal oedema with resultant endotracheal intubation dificulties in obstetrics should be remembered when endotracheal intubation is considered to avoid the hazard of acid aspiration. The authors prefer the use of regional anaesthetic techniques (if not contraindicated) in obstetrics, and emphasize the use of prophylactic methods to minimize the risk of acid aspiration in connection with general anaesthesia, particularly where endotracheal intubation may be diflicult.
Epidural Analgesia and Perinatal Retinal Haemorrhages
Authors: Maltau J. M. , Egge K.
Published: January 2009

The incidence and magnitude of retinal haemorrhages in a group of neonates delivered spontaneously (n = 50), whose mothers received epidural analgesia during labour, has been compared to those of a spontaneously delivered control group (n=50) who received conventional analgesia. The second stage of labour was significantly longer in the epidural group (P<0.001), which contained a higher number of primiparas than did their controls. Still, a lower incidence of retinal haemorrhages was noted in the epidural group (P<0.01).

The study indicates that epidural analgesia offers a certain degree of protection against perinatal retinal haemorrhages in the spontaneously delivered neonate.
Effects of Hydrocortisone, Phenoxybenzamine and Propranolol on the Blood Plasma Levels of Adrenaline and Noradrenaline During Hemorrhagic Hypotension in the Dog
Authors: Hellman A. , Häggendal E. , Häggendal J. , Lundberg D.
Published: January 2009

The adrenergic aspects of the mechanism(s) of the vasodilating action of phenoxybenzamine and massive doses of hydrocortisone were studied in anesthetized dogs subjected to controlled hemorrhagic shock. During the predrug hypotension period with decreased cardiac output and heart rate, the plasma adrenaline and noradrenaline levels were both increased. Phenoxybenzamine injected alone augmented the cardiac output and heart rate and reduced the plasma adrenaline without changing the plasma noradrenaline concentration.

However, if the adrenergic alpha‐receptor blocker was administered in combination with massive doses of hydrocortisone, the degree of vasodilation increased further with a concomitant increase in the concentrations of the two plasma catecholamines. Thus there seems to he no clear‐cut relationship between hemodynamic changes and plasma catecholamines. The present findings illustrate the extreme complexity of plasma catecholamine kinetics during hypovolemic shock.
Lidocaine Concentration in Blood after Topical Anaesthesia of the Upper Respiratory Tract
Authors: Rosenberg P. H. , Heinonen J. , Takasaki M.
Published: January 2009

The venous blood concentration oflidocaine was determined after stepwise application of lidocaine spray (270 mg) to the upper respiratory tract in 10 patients scheduled for bronchography, and after oropharyngeal application (150 mg) to live intubated patients under general anaesthesia. The peak level oflidocaine (about 1 pg/ml) occurred 20–30 min after spraying in the bronchography group, while there was a level plateau at about 0.5 pg/ml after oropharyngeal application of the local anaesthetic. There was great variation in the lidocaine concentration in both groups, but the highest observed concentration, 2.7 μg/ml, was safely below the toxic level. The mean rise in systolic and diastolic blood pressures at the various stages of spraying and on passing the bronchography tube in the local anaesthesia patients was 14.5–17.5/6.5–11 mmHg (1.9–2.3/0.9–1.5 kPa) compared to preanaesthetic values. In a similar group of patients, also scheduled for diagnostic bronchography, thiopentone anaesthesia, succinylcholine relaxation and laryngotracheal lidocaine spray resulted in a peak blood pressure increase of 36.5/27 mmHg (4.9/3.6 kPa) on passing the tube. The mean increases in pulse rate (21–26/min) were similar in both bronchography patient groups. No serious cardiac arrhythmias were observed in any of the patients.
Renal Fluoride Excretion During and After Enflurane Anaesthesia: Dependency on Spontaneous Urinary pH‐Variations
Authors: Järnberg P. O. , Ekstrand J. , Irestedt L. , Santesson J.
Published: January 2009

Renal function, fluoride formation and excretion were studied in seven patients during and after enflurane anaesthesia and surgery. The mean maximal plasma level of fluoride was 17.4 pM. It was reached 2 h after termination of anaesthesia. Pre‐operatively, fractional fluoride clearance (CF/CIn) was 0.31. During anaesthesia and surgery it decreased to 0.10 and postoperatively rose to 0.55 and 0.77 during two consecutive measurement periods. There was a highly significant correlation (P<0.001) between this increase in CF/CIn and the simultaneous rise in urinary pH between the two periods (r=0.91).
The Cortisol Fluctuations in Plasma in Relation to Human Regulatory Nonshivering Thermogenesis
Authors: Jessen K.
Published: January 2009

It is known that many stressful situations are accompanied by an increase in plasma cortisol concentration. This study was undertaken to see if a standardized and moderate exposure to cold under simultaneous peripheral vasodilatation, which is known to result in increased oxygen consumption and plasma concentration of noradrenaline, can be considered a stress, based on changes in plasma cortisol concentration. Since the nonshivering thermogenesis induced is dependent on normal thyroid function, nine of the 19 adult humans exposed to cold were normo‐, four hyper‐, and six hypothyroid. The cold exposure was carried out in every case between 9 a.m. and 11 a.m. Since the cortisol secretion reflects the circadian cycle, a further six normothyroid persons were exposed to cold between 5 a.m. and 7 a.m. The exposure in this study does not reflect any stress condition, as the plasma cortisol concentration during the investigations between 9 a.m. and 11 a.m. decreased significantly by mean values of 0.1 mmol/l (29%) (range: ‐0.07–0.2mmol/l) in the norrnothyroid group, by 0.23 mmol/l (68%) (range: 0.09 ‐ 0.44 mmol/l) in the hyperthyroid group, and by 0.16 mmol/l (29%) (range: 0.03 ‐ 0.38 mmol/l) in the hypothyroid group. The normothyroid persons investigated between 5 a.m. and 7 a.m. showed a significant fall similar to that mentioned above. The differences in the results obtained between the norrno‐ and dysthyroid groups, before and during the exposure, merely reflected variations known from non‐stressful conditions.
Skeletal Muscle Oxygen Pressure Fields in Rats: A Study of the Normal State and the Effects of Local Anesthetics, Local Trauma and Hemorrhage
Authors: Lund N. , ÖDman S. , Lewis D. H.
Published: January 2009

The MDO (Mehrdraht Dortmund Oberflache) oxygen electrode was used for studies of oxygen pressure fields in rat skeletal muscle. With this multiwire oxygen electrode, the three‐dimensional oxygen pressure field was measured and presented as a two‐dimensional frequency distribution, i.e. a histogram. Statistical analysis of the histograms was carried out with the two‐sample Kolmogorov‐Smirnov test. This eliminated the influence of mean values, since these do not always represent the actual biological situation. The oxygen pressure fields in skeletal muscle of anesthetized normal rats breathing air spontaneously were investigated. When the oxygen pressure in the inspired gas was changed (50% and 95%), changes were seen in muscle oxygen pressure curves. The normal oxygen pressure field histograms were compared with those obtained after local anesthesia, after local trauma to the muscle and after hemorrhage. After local anesthesia the histograms were unchanged. Significant changes in the distribution types of the histograms were found after trauma in all rats studied. After hemorrhage significant changes, similar to those seen after trauma, were found in 15 of the 23 rats studied. Local blood flow was also measured with the 133xenon‐clearance method in the hemorrhage experiments. No correlation was found between the changes in the mean oxygen tension values and the changes in 133xenon‐clearance.
Plasma Concentrations of Lidocaine (Lignocaine) After Cranial Subcutaneous Injection During Neurosurgical Operations
Authors: Kanto J. , Jalonen J. , Laurikainen E. , Nieminen V. , Salo M.
Published: January 2009

After cranial subcutaneous injection of lidocaine 0.8–3.7 mg/kg+ adrenaline (epinephrine) 1:200,000 in neurosurgical patients, fast drug absorption was found with peak plasma concentrations of 0.6–1 μg/ml in 5–10 min. However, the concentrations remained above the lowest effective antiarrhythmic level of 0.6 μg/ml for only about 10 min. In one patient, simultaneously administered intravenous lidocaine had an additive effect on those levels. Induced hypotension (sodium nitroprusside) during aneurysm operations decreased the arterial plasma level of lidocaine and was followed by a new peak after discontinuation. Thus the absorption of a drug during induced hypotension from subcutaneous tissue is often erratic.
Heart Rate‐Systemic Blood Pressure Relationship in Dogs During Halothane Anesthesia
Authors: Wilkinson P. L. , Stowe D. F. , Glantz S. A. , Tyberg J. V.
Published: January 2009

We have quantified the sensitivity and range of response of baroreflex‐mediated heart rate changes during halothane anesthesia. Anesthesia was induced in 10 dogs with sodium thiopental (4 mg/kg i.v.), morphine sulfate (1 mg/kg), and succinylcholine (0.5 mg/min) was infused. After instrumentation, we infused sodium nitroprusside (0.1 mg/ml) or gave phenylephrine in divided doses (0.05 mg i.v.) at end‐tidal halothane concentrations of 0.5%, 1.0%, and 2.0%. We changed systolic pressure over the range 6.5–26 kPa, measuring systolic pressure and heart rate responses at 1.3–2.6 kPa intervals. We found that the sigmoid curve relating heart period and systolic pressure was displaced leftwards, and the range of reflex response was significantly depressed (P<0.001) at 2% halothane concentrations. The maximum slope of the curve was significantly depressed (P<0.001) at increasing halothane concentrations. We conclude that halothane depresses the slope of the relationship between blood pressure and heart rate. However, the reflex response range is only depressed at high halothane concentrations, and the curve is displaced in the direction of lower heart rates at any given systemic pressure.
Influence of Sodium Nitroprusside and Dobutamine on the Haemodynamic Effects Produced by Each Other
Authors: Meretoja O. A.
Published: January 2009

To determine the possible modifying influence of potent inotropic medication and of sodium nitroprusside on the haemodynamic effects produced by each other, ten patients were treated 4 h after open‐heart surgery with constant infusions of nitroprusside (NP) and dobutamine (DOB), separately and in combination. In consequence of reduced left ventricular filling pressure, NP produced, the cardiac index fell tolerably, although systemic and pulmonary vascular resistances were typically lowered. These haemodynamic effects of NP were identical, with and without simultaneous DOB‐infusion.

Dobutamine (6 μg/kg/min) did not affect systemic or pulmonary arterial mean pressures, nor the filling pressures of right or left ventricle. It augmented the cardiac index by 18%, but as a result of a 17beats/minrisein heart rate, the stroke volume remained unchanged during DOB‐infusion, whereas systemic vascular resistance was significantly lowered. The cardiovascular responses to DOB were independent of the simultaneous NP‐infusion.

To conclude, the haemodynamic changes brought about by NP or DOB are not affected by each other, but when combined they produce additive, beneficial haemodynamic effects. Myocardial oxygen consumption, reflected as the rate‐pressure‐product (R‐P‐P), was slightly reduced during the combination therapy, due to the summation of the marked decrease of R‐P‐P which KP produced and the moderate increase of R‐P‐P produced by DOB.
Cyclic AMP and Metabolic Substrates Following Hemorrhage in Awake and Anesthetized Rats
Authors: Farnebo L. O. , Fredholm B. B. , Hamberger B.
Published: January 2009

The levels of several metabolites in plasma were studied during a period of 4 h in awake and barbiturate‐anesthetized rats after a blood volume loss of approximately 3% of b.w. Blood pressure was 70 mmHg (9.3 kPa) in the awake and 35 mmHg (4.7 kPa) in the anesthetized rats. Resting levels of plasma glucose, blood lactate and pyruvate and plasma cyclic AMP were higher in the awake rats than in the anesthetized rats. Bleeding caused an increase of plasma glucose in both groups. There was a more rapid increase in blood lactate and pyruvate as well as in plasma cyclic AMP levels in the awake rats than in the anesthetized rats. By contrast, plasma glycerol levels were unaltered by bleeding, and plasma FFA levels were decreased in both groups. At the end of the 4‐h bleeding period plasma glucose was higher and blood lactate levels were lower in the awake rats. The initial changes in plasma metabolite levels appeared to be directly related to changes in plasma catecholamine levels. There were no differences in the relationship between the adrenaline level and cyclic AMP or glucose increase, suggesting that anesthesia did not alter P‐adrenoceptor sensitivity, but only catecholamine concentrations. The results also indicate that awake rats tolerate long‐lasting blood volume loss better than anesthetized rats, because the sympatho‐adrenal activation is more short‐lasting.
Haemodynamic Effects of Combined Nitroglycerin‐ and Dobutamine‐Infusions After Coronary By‐Pass Surgery With One Nitroglycerin‐Related Complication
Authors: Meretoja O. A.
Published: January 2009

The haemodynamic effects of separate and simultaneous nitroglycerin (NTG) ‐ and dobutamine (DOB) infusions were determined in order to evaluate the nature of the effects of combined treatment. Ten patients were studied, 6 h after coronary by‐pass surgery. NTG alone reduced significantly systemic and pulmonary arterial, as well as ventricular filling pressures, and brought about a concomitant 10% decrease in the cardiac index (P<0.05). Dobutamine (6 μg/kg/min) did not affect systemic or pulmonary arterial pressures, nor ventricular filling pressures. As a result of the 20 beats/min rise in heart rate produced by DOB, the cardiac index was increased by 24%, whereas the stroke volume and work indices remained unchanged during DOB‐infusion. The haemodynamic changes brought about by either NTG or DOB separately were unaffected by the simultaneous infusion of the other vasoactive drug. The haemodynamic effects of the combined treatment were simply the sum of their separate effects, thereby yielding reduced arterial and ventricular filling pressures, increased heart rate, and slightly augmented cardiac index with significantly reduced systemic vascular resistance; myocardial oxygen consumption was unaffected by the combination therapy. One patient, whose case is discussed separately, had a hypotension‐bradycardia complication during NTG‐infusion.
Risk Factors in Surgical Patients with Verified Preoperative Myocardial Infarction
Authors: Eerola M. , Eerola R. , Kaukinen S. , Kaukinen L.
Published: January 2009

A series of 89 surgical patients (111 operations) with preoperative myocardial infarction (MI) was analysed for factors predisposing to the development of a postoperative reinfarction. Six of them suffered postoperative MI, and three of these patients died. In the statistical analysis the following risk factors emerged: age over 60 years, anaemia, hypertension, and the fact that the previous MI had been posterior. Abdominal operations were more dangerous concerning reinfarction than other operations. In the other series of 11 deceased patients with postoperative reinfarction collected from the autopsy material, about the same risk factors were found. The most important factor seemed to be hypotension, which complicated the surgery. All 11 patients had arrhythmias in their preoperative electrocardiogram. Previously treated heart failure was present in five of these patients. Postoperative symptoms analysed in the first series suggest that if a patient with preoperative MI has arrhythmias, hypotension, dyspnoea, diffuse unlocalized pain or chest pain after sugery, he is very likely to have a reinfarction.
In Vivo Lung Lavage as an Experimental Model of the Respiratory Distress Syndrome
Authors: Lachmann B. , Robertson B. , Vogel J.
Published: January 2009

Using adult guinea‐pigs, we have developed an experimental model in which alveolar surfactant phospholipids are removed by repeated lung lavage in viao, and in which the short‐term survival of the animals is ensured by artificial ventilation. Blood gases, parameters of lung mechanics, and histologic and electron microscopic findings indicate that the lavage procedure induces a condition similar to the adult respiratory distress syndrome. We propose that our technique might be used for evaluation of pharmacological agents and various forms of artificial ventilation which have been suggested for treatment of this disease.
Temperature Variations in Disposable Heat and Moisture Exchangers
Authors: Revenäs B. , Lindholm C. E.
Published: January 2009

Temperature variations in different parts of three heat and moisture exchangers (HME) were measured during spontaneous breathing. Temperatures below ambient occurred in the distal part of two of them. The lowest temperatures recorded were more than 6°C below room temperature. This effect can explain why gas expired through a good HME is not saturated with water at ambient temperature.
Peripheral Circulation During Sufentanyl and Morphine Anesthesia
Authors: Berthelsen P. , Eriksen J. , Ahn N. Chr. , Rasmussen J. P.
Published: January 2009

Sufentanyl is a newly developed potent, short‐acting fentanyl‐like morphinomimetic. No independent studies of the peripheral circulation during sufentanyl anesthesia are available. In the present study we compared the effects of sufentanyl and morphine on the peripheral perfusion in dogs. The effects of total β‐blockade during sufentanyl and morphine anesthesia were also evaluated. We elected to record skeletal muscle surface pH (m‐pH) continuously as an index of the microcirculation and cellular function. Arterial and mixed venous blood gases and acid‐base status were measured to determine the respiratory component of changes in m‐pH. Hematocrits, plasma electrolytes and plasma proteins were analyzed in order to permit calculations of fluid‐shifts between the blood and the interstitial fluid. Sufentanyl (0.01 nig/kg) had no adverse effects on the peripheral perfusion. Morphine (4 mg/kg) caused a severe and rapid fall in m‐pH from 7.29 to 7.11 during the 30‐min experimental period. At the same time, calculated blood volume decreased by 20%. This hypovolemic deterioration of the circulation was probably caused by a histamine‐mediated increase in capillary pressure with filtration of plasma from the circulation to the interstitial fluid.

Calculated systemic vascular resistance was not correlated to the quality of the peripheral perfusion. Propranolol administered during sufentanyl and morphine anesthesia did not influence the peripheral perfusion. On the basis of the present study we recommend human studies on sufentanyl, and discourage the use of high‐dose morphine anesthesia.
Cerebral Blood Flow in the Acute Phase After Head Injury: Part 1: Correlation to Age of the Patients, Clinical Outcome and Localisation of the Injured Region
Authors: Cold G. E. , Jensen F. T.
Published: January 2009

In 40 comatose patients with severe head injury, a total of 114 rCBF studies were performed with the intraarterial 133xenon washout technique over the most severely injured hemisphere. All patients were subjected to respirator treatment, and mildly sedated with diazepam, chlorpromazine or meperidine. The average values of the regional flow were corrected for changes in Paca by simultaneous measurements of CO2 reactivity. A Paco2 value of 30 mmHg (4 Pa) was chosen as the reference value. The results indicate that hyperaemiafollowinghead injury is a common phenomenon, especially in young victims with supratentorial cortical lesions. The hyperaemic phase can last from some days to several weeks and is of no prognostic significance. In elderly patients with supratentorial cortical lesions, and in patients with mainly brain‐stem lesions or diffuse brain lesions a persistent low flow state was observed in the acute phase (first 1–3 days after the injury). This low flow state was also observed 1–2 weeks after the injury if loss of consciousness persisted, but it was of no prognostic significance, as CBF values between 15 and 20 m1/100 g/min were associated with a good recovery.
The Pulmonary Vasoconstrictor Response to Hypoxia during Enflurane Anesthesia
Authors: Bjertnæs L. J. , Mundal R.
Published: January 2009

Previous investigations have shown that diethyl ether, halothane and methoxflurane inhibit the vasoconstrictor response to hypoxia in isolated rat lungs. A damping effect of diethyl ether and halothane has been observed in the human lung as well. In the intact dog lung, however, other workers have recently denied any effect of halothane and enflurane on this vasoconstrictor mechanism. These findings challenged us to investigate the effect of enflurane on the vasoconstrictor response to hypoxia in isolated rat lungs. We found that enflurane administered via the airways reduced the response in proportion to the end‐tidal concentration of enflurane, as determined by mass spectrometry.
A Technique for Disinfection of the MDO Oxygen Electrode
Authors: Lund N. , Cardell B. , Törnell B. M. , ÖDman S.
Published: January 2009

A method for disinfection and aseptic assembly of the MDO (Mehrdraht Dortmund Oberfläche) oxygen electrode has been evaluated. The method is based on treating each electrode component separately and then assembling the different parts under aseptic surgical conditions. The performance of the disinfected electrode was studied and found to be unchanged as compared with a non‐disinfected electrode. Bacteriological studies on the effectiveness of the disinfection technique described and on the permeability of the electrode membranes to bacteria and bacterial spores were performed. The electrode membranes were penetrated by bacteria in experiments simulating in‐use conditions in about 11 % of membranes tested, after contamination of the inner electrode surface with heavy inocula. When studies were performed with the disinfected MDO oxygen electrode on humans, routine cultures from the wound were positive in about 10% of the cases. No clinical wound infection was seen. The majority of the positive cultures were probably caused by the surgical technique rather than the handling of the electrode. The disinfection method for the MDO oxygen electrode described in this paper makes it possible to use the electrode clinically, except in cases of hepatitis.
Effects of the Level of CPAP on Central Haemodynamics and Oxygen Transport
Authors: Vuori A.
Published: January 2009

The effects of different levels of continuous positive airway pressure (CPAP) on central haemodynamics and oxygen transport were studied in ten spontaneously breathing male patients who had undergone aortocoronary bypass graft operation 18 h earlier. With increasing CPAP levels ranging from 5 cm H2O (0.49 kPa) (CPAP 5) to 15 cmH2O (1.47 kPa) (CPAP 15), the cardiac index was found to decrease significantly, while the intraluminal pulmonary capillary wedge and right atrial pressures increased simultaneously. The mean systemic arterial pressure remained unaltered, while the mean pulmonary arterial pressure increased with increasing CPAP. Systemic oxygen transport changed concomitantly with the changes in cardiac output, since arterial blood oxygen content was not altered. The mixed venous blood oxygen tension decreased with increasing CPAP, as did the cardiac output. No changes in the total oxygen consumption or in the arteriovenous oxygen content difference were found at the various CPAP levels. Pulmonary vascular resistance was significantly higher during CPAP 0 than during CPAP 5, possibly indicating development of local pulmonary vasoconstriction following hypoxia caused by closure of the small airways as a consequence of a reduction in the functional residual capacity during CPAP 0. Thus, low level CPAP might be beneficial in maintaining proper lung volume in an intubated patient after aortocoronary bypass surgery. The observations also suggest that, in these patients, CPAP levels exceeding 10 cmH2O bring about cardiac depression leading to an undesirable reduction in systemic oxygen transport. Mixed venous blood oxygen tension may offer information useful in the adjustment of the level of CPAP.
Airway Closure and Closing Pressure During Mechanical Ventilation
Authors: Hedenstierna G. , McCarthy G. S.
Published: January 2009

Six subjects without clinical evidence of lung disease were investigated for airway closure and airway closing pressure before and during fentanyl‐thiopentone anesthesia with mechanical ventilation. Airway closure was measured by single breath and FRC by multiple breath nitrogen washout. Airway closing pressure was taken to be the transpulmonary pressure at which airway closure commenced.

Airway closure occurred within a normal breath in two out of six subjects breathing spontaneously, but in all during mechanical ventilation. Closing capacity was the same in both the awake and anesthetized states while FRC was reduced by 0.4 1 when anesthesia was instituted. Transpulmonary pressure at FRC was on average 1.5 cmH2O (0.15 kPa) and airway closing pressure 4.5 cmH2O (0.44 kPa) greater during anesthesia than in the awake state. Compliance of the lung, calculated both during a vital capacity maneuver and during a tidal breath, was lower with anesthesia. The results of this study suggest that the airways are less stable during mechanical ventilation. But, since lung compliance is lower during anesthesia, a higher transpulmonary pressure is required to maintain a given lung volume. Hence, airway closure occurs at the same lung volume in the anesthetized compared to the non‐anesthetized subject.
High Pressure, Diazepam and pH Influences on Ketamine Anaesthesia in the Rat
Authors: Gran L. , Kayfmann P. , Bennett P. B.
Published: January 2009

Ketamine infusion anaesthesia was studied in rats breathing oxygen/helium under hyperbaric conditions from 1 to 90 ATA. No pressure reversal of the analgesic effect was found. Premedication with diazepam failed to improve the analgesic action of ketamine, but influenced the respiratory pattern. Blood‐gas analyses showed a marked relationship between arterial pH and the ketamine dose requirement for stable anaesthesia.
Temperature‐Dependent Nerve‐Blocking Action of Lidocaine and Halothane
Authors: Rosenberg P. H. , Heavner J. E.
Published: January 2009

The effect of lidocaine and halothane on the compound action potential of rait sciatic nerves was studied under hypo‐ and hyperthermic conditions. In drug‐free desheathed nerves, a total but reversible cold block occurred at 10–11°C, and an irreversible heat block at 46°C. Cooling potentiated the dose‐dependent blocking action of lidocaine (decreased amplitude, and increased duration and latency of the compound action potential). Total block of conductioh'octurred at 17°C with 100 μM lidocaine, at 20°C with 200 μM lidocaine and at 24°C with 400 μM lidocaine. In nerhes equilibrated in 200 μM lidocaine solution, the lidocaine concentrations in the nerves decreased as the temperature decreased; at 20°C, the lidocaine concentration was about half of that at 37°C. The nerve‐blocking effect of lidocaine was also potentiated by increasing the temperature above 37°C. At 30°C and 20°C, 1 vol. % halothane caused a slight time‐dependent inhibition of the compound action potential. When the nerves were exposed to 2.5 vol. % halothane, the decrease in amplitude and increase in duration and latency were potentiated by hypothermia and were also time dependent. Interaction of halothane and temperature of 40°C was not significant. Although thermodynamic principles suggest similarities between high pressure and cooling in reversing anaesthesia, cooling was found to potentiate the anaesthetic effect of lidocaine and halothane in this study. Temperature may thus be an interesting physical variable in studying nerve‐blocking mechanisms.
Failure of Intramuscularly Administered Lorazepam and Scopolamine‐Morphine Premedication to Produce Amnesic Effects to Supplement Conduction Anaesthesia
Authors: Korttila K. , Levänen J. , Auvinen J.
Published: January 2009

Patients undergoing surgery under regional anaesthesia often prefer to be sedated and do not later want to recall the procedure. One hundred and twenty‐one patients scheduled for various surgical procedures underepidural, spinal, sacral, or brachial plexus blockades received 1 mg/kg of pethidine, 0.007 mg/kg of scopolamine, plus 0.14 mg/kg of morphine, or 0.03 mg/kg or 0.06 mg/kg of lorazepam intramuscularly as preanaesthetic medication before the operation. The patient's self‐assessments of degree of fatigue and apprehension were similar after each premedication when assessed before operation. Postoperative anxiety and confusion as well as need for postoperative care and supervision were greatest after 0.06 mg/kg of lorazepam. Significantly (P<0.05 to P<0.01) fewer patients given 0.06 mg/kg of lorazepam remembered different events and procedures carried out on them before and after operation than those given other premedications, but no significant differences were noted in patients' ability to recall the performance of operation when asked on the following day. Seventy‐seven, 63, and 57 % of patients receiving 0.06 mg/kg of lorazepam remembered the start of blockade, performance of operation, and stay in recovery room, respectively. Intravenous sedation should be preferred to these intramuscularly administered premedications if drug‐induced amnesia is sought to supplement local anaesthetic techniques.
Comparison of Glycopyrrolate, Atropine and Hyoscine in Mixture with Neostigmine for Reversal of Neuromuscular Block Following Closed Mitral Valvotomy
Authors: Bali I. M. , Mirakhur R. K.
Published: January 2009

Atropine, glycopyrrolate and hyoscine were compared in a mixture with neostigmine for the reversal of neuromuscular block in patients undergoing closed mitral valvotomy. Both atropine and glycopyrrolate were effective in counteracting the muscarinic effects of neostigmine. Glycopyrrolate was, however, associated with less initial increase in heart rate, a factor of importance in patients with mitral stenosis. The incidence of significant dysrhythmias was low in this small series. The control of secretions was better with glycopyrrolate. Administration of hyoscine was associated with unacceptable falls in heart rate and is not recommended.
Effect of Inspiration‐Expiration Ratio on Rebreathing with the Mapleson D System (Bain's Modification; Coaxial System)
Authors: Gabrielsen J. , van den Berg J. T. , Dirksen H. , Ruben H.
Published: January 2009

Rebreathing in the Mapleson D system with a varying fresh gas flow (FGF) was measured during an experimental set‐up, which consisted of a compliance lung delivering the exhaled gases with the same, fixed concentration throughout the experiment, a commercially available Bain's system and a respirator. While changes in compliance, airway resistance and dead space hardly influenced the degree of rebreathing, changes in ventilatory pattern did so when the length of the expiratory pause was changed. Thus, with the Vt used, which was not essentially greater than the capacity of the corrugated tube, a sufficiently long‐lasting expiratory pause made it possible to establish non‐rebreathing conditions with a FGF only slightly greater than the respiratory minute volume. Obviously, a short or no expiratory pause requires that the FGF rate be high enough to compensate for the lack of afresh gas reserve in the corrugated tube at the start of inspiration. In such cases the length of the corrugated tube becomes of minor or no importance.
Total Body and Splanchnic Thermogenesis in Curarized Man During a Short Exposure to Cold
Authors: Jessen K. , Rabøl A. , Winkler K.
Published: January 2009

To investigate thermoregulation independent of muscular contractions in adult man during a short period of exposure to cold, five examinations were carried out on four individuals who were unconscious due to persistent brain damage and who were totally curarized during the exposure. An increase was found in total body oxygen consumption of 0.043 mmol .kg‐1min‐1 (range: 0.038–0.049) or 25%, in plasma noradrenaline of 5.05 nmol‐11 (range: 2.48–6.73) or 132%, and in plasma non‐esterified fatty acids of 0.6mmol‐1 (range: 0.049–0.095) or 44%. No changes occurred in plasma adrenaline or plasma glucose. Splanchnic oxygen consumption increased and contributed significantly to that of the total body in only one of the four cases. These results indicate that regulatory nonshivering thermogenesis exists in adult man not acclimatized to cold, that it is mediated by noradrenaline, that the major fuel substrate for the increased energy demand is the triglycerides from the fat stores, and that the splanchnic area contributes only irregularly and to a small degree to this part of thermogenesis.
Closed Circle Systems A New Direction in the Practice of Anesthesia
Authors: Lin C. Y. , Mostert J. W. , Benson D. W.
Published: January 2009

On the basis of the near‐constant uptake of inhalation anesthetics at the alveolar membrane, the large closedcircuit vohime which acts as a buffer, and the effect of concentration on uptake, we have evolved a simple and practical technique of closed‐circuit anesthesia. After initial high flow wash‐in of anesthetic gases into the FRC, a nearly constant low fresh‐gas flow can be maintained.
Insensible Perspiration During Anaesthesia and Surgery
Authors: Reithner L. , Johansson H. , Strouth L.
Published: January 2009

Cutaneous and respiratory insensible perspiration were studied in patients during anaesthesia and surgery. The evaporative water loss from the respiratory tract was studied in 27 patients undergoing abdominal surgery. The method used was based on a fast‐acting aspiration psychrometer, and the expired gases were heated so that no condensation could occur before the gases reached the psychrometer. The evaporative water loss from the skin was studied in 18 patients undergoing abdominal surgery. The method used was based on estimation of the vapour pressure gradient immediately adjacent to the surface of the skin. It was shown that the evaporative water and heat loss from the respiratory tract during surgery amount to about 10 g.m‐2 h‐1 resp. 25kJ m‐2.h‐2 which is a 15 % increase in comparison with normal breathing in an indoor environment. The loss from the skin was about 10 g m‐2. h‐1 which does not differ from results obtained in healthy individuals in a corresponding environment.
Epidural Opiate and Perioperative Analgesia
Authors: Dirksen R. , Nijhuis G. M. M.
Published: January 2009

Epidural injections of 5 mg nicomorphine in 20 ml 5% glucose were given to 10 gynaecological patients to provide intra‐operative and post‐operative analgesia. Signs of changed nociception appeared within 5 min. The maximum change occurred within 20 min. Effectiveness was at least 31/2 h. After an observation period of 30 min, light general anaesthesia is supplemented to give excellent operating conditions. It is suggested that opiates produce these effects by a direct action on the endorphin “pain” modulatory system of human beings at spinal level.
Effect of Dextran on Fibrinolysis Inhibition Activity in the Blood after Major Surgery
Authors: Carlin G. , Karlström G. , Modig J. , Saldeen T.
Published: January 2009

Patients undergoing total hip replacement surgery were given 500 ml of 6% dextran 70 or 5% albumin by intravenous infusion on the third postoperative day when the post‐traumatic fibrinolysis inhibition has reached its maximum. The large increase in the fibrinolysis inhibition activity measured by a clot‐lysis system was counteracted by the infusion of dextran, whereas the albumin infusion had no such effect. The plasma concentration of antiplasmin (chromogenic substrate assay) and the immunologically determined plasma levels of the primary fibrinolysis inhibitor (an‐antiplasmin), an‐macroglobulin, α2‐antitrypsin and plasminogen were not changed after the infusion of dextran. It is hypothesized that dextran exerts its effect partly by interfering with the interaction between the primary fibrinolysis inhibitor, fibrin and plasrnin(ogen) and by enhancing the activation rate of plasminogen. This observed effect of dextran may be of importance in the prevention of deep venous thrombosis and pulmonary embolic complications, as well as pulmonary microembolism.
Systems Theory and the Anaesthetist
Authors: Bagshaw R. J.
Published: January 2009

The application of the various aspects of systems theory has increased steadily over the last 10 years and has proved useful in such diverse fields as surgical services (Spratt et al. 1974), public health (Haas 1974), education (Harrington 1966), nephrology (Bigelow et al. 1973), medical information (Davis 1973), behavior (Shooster 1974), internal medicine (Guyton et al. 1972), metaphysics (Gayer 1972), and sociology (Attinger & Millendorfer 1968). More recently, rystems analysis has been applied to anaesthetic systems in the engineering literature (Smith & Schwede: 1972) and has begun to appear in the anaesthesia literature (Brows 1973). The anaesthetist in the operating room is part of a complex system. In its simplest form the latter involves the anaesthetist, the anaesthesia delivery system, the patient and the surgeon. This discussion is intended to introduce the anaesthetist to some of the terminology and techniques common to the systems analysis approach. Examples have been drawn from biological aystems in man which have proved useful to describe in feedback control terms. Where possible, the examples used are those most relevant to anaesthesiology.
Intradermal Histamine Releasing Effect Caused by Org‐NC 45 A Comparison with Pancuronium, Metocurine and d‐Tubocurarine
Authors: Boorj L. H. D. J. , Erieg N. , Crul J. F.
Published: January 2009

Hiatamine release caused by Org‐NC 45, pancuronium, metocurine and d‐tubocurarine was determined by measuring the diameter of the redness and skin induration following the intradermal injection of these drugs. d‐Tubocurarine and metocurine caused the largest diameter of redness and induration, followed by pancuronium.

Org‐NC 45 caused the smallest reaction. We conclude that Org‐NC 45 may be the drug of choice in patients with asthma and allergic reactions.
The Use of Dioxonium as a Neuromuscular Blocking Agent
Authors: Salmenperå M. , Tammisto T.
Published: January 2009

The feasibility of using dioxonium (Dx) as a neuromuscular blocking agent was evaluated in 66 patients anaesthetized for various surgical operations. To facilitate endotracheal intubation, initial bolus doses of 30,45 or 60 pg/kg were used. The onset and duration of block, as revealed by suppression of evoked twitch (thumb adduction) were measured in 30 patients with a force tranducer. Ten patients received 75pg/kgofpancuronium for comparison. Spontaneous and neostigmine‐supported recovery were compared after the three Dx doses. In 36 patients submitted for longer procedures, relaxation was maintained with additional 0.5 mg increments of Dx when needed.

Increasing the initial bolus dosage of Dx from 30 μg/kg to 0 μg/kg accelerated the onset of a 90% block from 3.3 to 2.4 min and prolonged its duration from 23.1 to 32.9 min. The onset of block after 60 pg/kg of Dx was aignilicantly faster than obtained after 75 pg/kg Pc, which produced a 90% block of a comparable duration. The fade observed in the train of four stimulation at the same level of twitch suppression increased with the total dose of Dx used. This and the significant reversing effect of neostigmine after 45 and 60μg/kg, but not after 30 μg/kg of Dx indicated the dosage‐dependent change in the nature of the block from depolarizing to nondepolarizing. Side effects related to ciepolarization seemed to be minimal, hardly visible faxiculations occurring in 5 out of 12 patients after 60 pg/kg and in one out of 12 after 30 and 45 pg/kg of Dx. Residual muscle weakness incompatible with airusay maintenance and adequate spontaneous ventilation was encountered in 3 out of 66 patients, in spite of neostigrnine up to 4 mg. These patients had received over 100 μg/kg of Dx for procedures requiring maintenance of relaxation for over 2 hours, The dose‐dependent change in the nature of the block, the associated tachyphylaxis, and the unpredictable reversal with neostigmine after higher doses emphasize the need for careful monitoring of the neuromuscular junctions when Dx is used.