bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of the effects of neostigmine and edrophonium on the duration of action of suxamethonium
Authors: McCoy É. P. , Mirakhur R. K.
Published: January 2009

Rapid sequence induction of anaesthesia necessitating the use of suxamethonium may occasionally be needed soon after antagonism of neuromuscular block with anticholinesterase agents. The onset and duration of action of 1 mg kg‐1of suxamethonium was recorded in groups of 10 patients each, 5 or 10 min after the administration of edrophonium 1 mg kg‐1or neostigmine 40 μg kg‐1given for the antagonism of atracurium‐induced neuromuscular block. Plasma cholinesterase activity was measured before, and 5 and 10 min after the administration of the anticholinesterases. A further 10 patients received suxamethonium 1 mg kg‐1without prior atracurium or anticholinesterase administration to serve as controls. The onset of action of suxamethonium was significantly prolonged when administered 5 min after both anticholinesterases, compared to the control group (P<0.01). Recovery of suxamethonium block was delayed significantly after neostigmine, compared to both the edrophonium and the control groups (P<0.05–0.001). Plasma cholinesterase activity was significantly reduced with the use of neostigmine but not with edrophonium (P<0.001).
Epidural anesthesia modifies cardiovascular responses to severe hypoxia in dogs
Authors: Shibata K. , Taki Y. , Futagami A. , Yamamoto K. , Kobayashi T.
Published: January 2009

Hypoxia is a critical and sometimes fatal complication of anesthesia. Since there is little information on the cardiovascular response to hypoxia during epidural anesthesia, we assessed the effects of epidural anesthesia on the cardiovascular response to hypoxia and on survival in dogs.

We randomly assigned 36 mongrel dogs to one of three groups according to the anesthede technique used: the thoracic group (n=12) received thoracic epidural anesthesia plus general anesthesia, the thoracolumbar group (n=12) received thoracolumbar epidural anesthesia plus general anesthesia, and the control group (n=12) received general anesthesia alone. We monitored hemodynamics and plasma catecholamine concentrations and assessed survival in these groups during normocapnic hypoxia (FiO2, 0.09 for 120 min).

During hypoxic challenge, PaCO2 and PaO2 values were similar in all groups. In both groups that received epidural anesthesia, heart rate, systolic and diastolic arterial pressures, and plasma epinephrine and norepine‐phrine concentrations were lower and arterial pH was greater than in the control group. There was no significant difference in survival among groups.

Epidural anesthesia modified both the physiologic cardiovascular and catecholamine responses to hypoxia. Epidural anesthesia of the thoracic region did not appear to accelerate cardiac arrest, but it attenuated the development of metabolic acidosis during hypoxia.
Comparison of vascular effects of ropivacaine and lidocaine on isolated rings of human arteries
Authors: Gherardini G. , Samuelson U. , Jernbeck J. , ÅBerg B. , Sjöstrand N.
Published: January 2009

Ropivacaine is a new local anaesthetic agent. Previous animal studies have indicated that vasoconstrictor effects are elicited by ropivacaine in vitro and subcutaneously and that it produces blanching of the skin if injected subcutaneously in humans.

Lidocaine is a widely used local anaesthetic reported to exert a biphasic effect on the microvasculature with contraction at low concentrations and relaxation at high concentrations. There is a need for pharmacologic tools able to counteract local arterial vasoconstriction. In this study, the contractile effect of ropivacaine and lidocaine were investigated in vitro on isolated human arteries.

Experiments were performed on 43 internal mammary artery (IMA) rings obtained from 22 patients and on 14 radial artery (RA) rings from 7 patients. The rings were mounted in organ baths and isometric contractile activity was measured. Experiments were conducted by cumulative adding ropivacaine or lidocaine (1.5X10‐5 M; 4.5X10‐5 M; 1.5X10‐4 M; 4.5X10‐4 M; 1.5X10‐3 M; 4.5X10‐3 M; 1.5X10‐2 M) to the organ baths. The endothelium was mechanically removed in 19 IMA rings and in 9 RA rings.

Ropivacaine and lidocaine produced a biphasic response with contraction at low concentrations (1.5X10‐5 1.5X10‐3 M) and release of the maximal contraction at higher concentrations. No statistically significant differences in contractile or relaxing effects were seen between the two drugs. Removal of the endothelium did not significantly affect contractile activity. In this study of human mammary artery preparations, ropivacaine is not a stronger vasoconstrictor than lidocaine.
Effects of sevoflurane on respiratory activities in the phrenic nerve of decerebrate cats
Authors: Masuda A. , Haji A. , Kiriyama M. , Ito Y. , Takeda R.
Published: January 2009

Although the depressive effect of sevoflurane on ventilation has been reported, its potency and mode of action on the neural respiratory activity is still unclear. Therefore, the effects of sevoflurane on the phrenic nerve discharge and the respiratory timing were compared with those of halothane.

The efferent activity of the phrenic nerve was recorded from decerebrate, un‐anesthetized and artificially ventilated cats, and its power spectrum was calculated. The inspiratory and expiratory periods were measured. Sevoflurane and halothane of the doses of 0.5–1.5 MAC were inhaled for 15 min.

With 0.5 MAC, sevoflurane decreased the total power and two dominant spectral components of the high‐frequency oscillation and medium‐frequency oscillation in the power spectrum. With the same MAC dose, halothane had a greater depressive effect in a normocapnic condition with the vagus nerves being intact. In a state of hypercapnia or after vagotomy, the effect of halothane was considerably attenuated whereas that of sevoflurane remained unaltered. Halothane increased the neural respiratory rate much more than sevoflurane in both normocapme and hypercapnic states. Vagotomy significantly weakened the effect of halothane to increase the respiratory rate but did not modify the effect of sevoflurane. With 1.0–1.5 MAC, both anesthetics severely decreased the phrenic power spectra and the potency difference became indistinct.

The present findings demonstrate that sevoflurane has a weaker depressive effect on the respiratory nerve discharge and a smaller effect on the neural respiratory rate than halothane when the effects of 0.5 MAC were compared. This may be due to the lesser effect of sevoflurane on the vagal mediated and CO2‐related mechanisms which modulate the global outputs of the central respiratory control system.
Anaphylactoid skin reactions after intravenous regional anaesthesia using 0.5% prilocaine with or without preservative — a double‐blind study
Authors: Kajimoto Y. , Rosenberg M. E. , Kyttä J. , Randell T. , Tuominen M. , Reunala T. , Rosenberg P. H.
Published: January 2009

Methylparaben, the preservative of various local anaesthetic solutions, is a potential allergen.

In a double‐blind study, 0.5% prilocaine with (Citanestr̀, n=100) or without (n=100) methylparaben were compared for the occurrence of skin reactions after intravenous regional anaesthesia of the arm in surgical patients. Skin reactions were registered after the deflation of the tourniquet cuff, and intradermal tests were performed with 0.5% prilocaine, 0.1% methylparaben and saline in all patients. Seventeen patients in the Citanestr̀ group and four patients in the methylparaben‐free prilocaine group developed erythematous skin reactions in the exposed arm after deflation of the tourniquet cuff (P<0.05, between the groups). The skin symptoms disappeared within an hour and were always restricted to the region which had been anaesthetised. None of the affected patients had positive intradermal tests.

The observed skin reactions are probably non‐IgE‐mediated anaphylactoid reactions in which the presence of methylparaben in the local anaesthetic solution plays a major role.
Evaluation of left ventricular diastolic function in IgE‐mediated anaphylaxis in dogs
Authors: Mitsuhata H. , Hasome N. , Saitoh J. , Takeuchi H. , Horiguchi Y. , Shimizu R.
Published: January 2009

Depressed left ventricular (LV) systolic function remains controversial in patients with anaphylaxis and anaphylactic animal models. However, LV diastolic function has not yet been investigated in either patients or animal models. Therefore, we assessed LV diastolic and systolic function in IgE‐mediated anaphylaxis in dogs. Seven dogs sensitized to Ascaris suum antigen were studied. An aqueous extract of Ascans suum antigen was administered over 30 s into the systemic circulation to induce anaphylaxis. To assess LV function, the time constant of the fall of isovolumic LV pressure (T), as an index of LV diastolic function, and the maximum rate of rise of LV pressure (dP/dtmax), as an index of LV systolic function, were measured for a period of 120 min after antigen challenge. T was prolonged during the period of 5 to 15 min; however, changes in T were not significantly different from prechallenge values. LV dP/dtmax significantly decreased to 0.49±0.12 times the prechallenge value 5 min after antigen challenge, and significantly increased during the period from 30 to 120 min. However, these changes in dP/dtmax almost paralleled the changes in LV end‐diastolic pressure, indicating that left ventricular systolic function was relatively well preserved. In conclusion, LV diastolic function, i.e., isovolumic relaxation, is little impaired in anaphylaxis, and IV systolic function is relatively well preserved during the early stage following the onset of anaphylaxis.
Spinal anesthesia attenuates myocardial ischemia during coronary artery spasm induced by intraaortic methacholine in rats
Authors: Mizuyama K. , Sato S. , Okubo N. , Naito H.
Published: January 2009

Coronary artery spasm is not rare in patients with coronary artery disease, but the influence of regional anesthesia on spasm‐induced myocardial ischemia is not known. We investigated the effects of spinal anesthesia on myocardial ischemia during coronary artery spasm in rats, and compared these with the effects of an alpha‐ and beta‐adrenergic antagonist, and an alpha‐adrenergic agonist.

An intraaortic catheter was inserted via the right internal carotid artery so that the tip of the catheter was placed near the coronary ostium. An intrathecal catheter was placed at lumbar level. Coronary spasm was induced by the intraaortic injection of methacholine, and we identified the thresholds of myocardial ischemia, defined as the dose of methacholine that induced ST‐segment elevation. Subsequently, the thresholds were determined after spinal anesthesia, and after the intraaortic injection of phentolamine and propranolol.

The thresholds of myocardial ischemia increased significantly after intrathecal bupivacaine. In contrast, the threshold did not change after the injection of phentolamine. The thresholds increased significantly after the injection of propranolol. Methoxamine significantly decreased the threshold of ischemia.

These results demonstrated that spinal anesthesia attenuated myocardial ischemia during methacholine‐induced coronary spasm. This effect was equivalent to that of propranolol.
QT interval of the ECG, heart rate and arterial pressure during anaesthetic induction: comparative effects of alfentanil and esmolol
Authors: Korpinen R. , Saarnivaara L. , Siren K.
Published: January 2009

In a double‐blind study the effect of esmolol and alfentanil on the QT interval of the ECG corrected by the heart rate (QTc), heart rate and arterial pressure during anaesthetic induction was studied in 59 oxycodone‐ and atropine‐premedicated ASA class I‐(II) patients with a mean age of 26 yr (range 15–50 yr). The patients were randomly allocated to one of the four groups: saline, esmolol 2 mg · kg‐1, esmolol 3 mg · kg‐1 or alfentanil 0.03 mg·kg‐1. Both doses of esmolol prevented the prolongation of the QTc interval after thiopental and suxamethonium, but not after laryngoscopy and intubation. Alfentanil prevented the prolongation of the QTc interval following thiopental, suxamethonium and laryngoscopy but not after intubation. Esmolol did not prevent the increase in the heart rate and arterial pressure in response to laryngoscopy and intubation. No cardiovascular responses to laryngoscopy and intubation occurred in the patients treated with alfentanil. No cardiac arrhythmias occurred in the esmolol 3 mg·kg‐1 group, whereas the frequency of ventricular ectopic beats was 40% in the saline group and 13–20% m the other groups.
Propofol and isoflurane induced EEG burst suppression patterns in rabbits
Authors: Hartikainen K. , Rorarius M. , Mäkelä K. , Yli‐Hankala A. , Jäntti V.
Published: January 2009

The aim of this study was to compare propofol produced EEG burst suppression with isoflurane produced burst suppression in rabbits and to see whether rabbits can serve as models in studying the effects of different anaesthetics on human EEG. We recorded EEG of eight rabbits anaesthetised with isoflurane and propofol. The isoflurane bursts had higher amplitude than propofol bursts (P<0.005). Isoflurane bursts appeared on distinct DC‐shifts while propofol bursts were on slow waves. The EEG patterns were, however, different from those seen in humans. Rabbits did not have the rhythms seen in humans. We conclude that rabbits can be used to study the EEG effects of anaesthetics, such as the timing properties and reactivity of burst suppression pattern. However, this model seems less promising in the study of rhythmic activity seen in human EEG during burst suppression.
The influence of anaesthetic drugs on the lower oesophageal sphincter in propofol/nitrous oxide anaesthetized dogs: Pressure profilometry in an animal model
Authors: van der Hoeven C. W. P. , Attia A. , Deen L. , Klopper P. J.
Published: January 2009

The lower oesophageal sphincter (LES) is the main barrier against gastro‐oesophageal reflux. Various anaesthetic drugs have been reported to affect the LES pressure. In this study, the effects of cisapride, atropine, suxamcthonium, vecuronium and pancuronium on the LES pressure of six mongrel dogs anaesthetized with propofol and nitrous oxide were investigated. By means of eight‐channel pressure profilometry the LES pressure was measured in consecutive sessions before and after administration of each drug. Compared to basal values, atropine and suxamethonium significantly decreased LES pressure, pressure vector volume and sphincter length. Cisapride significantly increased all sphincter parameters, vecuronium significantly increased LES pressure and pressure vector volume while pancuronium had no significant effects. A significant decrease of the LES pressure and pressure vector volume was observed when nitrous oxide was omitted from the ventilation mixture. Three‐dimensional imaging showed an asymmetric shape of the LES pressure which resulted from radial differences of the LES pressure. The results from this study show that both the anaesthetic animal model and the eight‐channel pressure profilometiy are useful procedures in studying the effects on sphincter function of different drugs during anaesthesia.
A porcine model for evaluation of cerebral haemodynamics and metabolism during increased intracranial pressure
Authors: Nilsson F. , ÅKeson J. , Messeter K. , Ryding E. , Rosén I. , Nordström C.‐H.
Published: January 2009

In patients with severe head injuries raised intracranial pressure (ICP) constitutes the most important cause of mortality. Several new therapies for increased ICP have recently been suggested and it is of importance to study the physiological effects of these treatments in animal experiments during steady state conditions. A porcine model for evaluation of cerebral haemodynamics and metabolism during increased ICP is presented. Intracranial hypertension was induced by inflation of two tonometric gastric balloons placed extradurally covering a major part of the parietooccipital region bilaterally. The distribution of the blood flow supplied by the carotid artery used for the cerebral blood flow (CBF) measurements was studied by intraarlerial (i.a.) injection of 99mTc‐HMPAO.

The measurements showed that following ligation of the external carotid and the occipital artery no accumulation of tracer substance occurred in extracranial tissues during normal or increased ICP. Cerebral physiological variables (CBF, Cavo2, and ICP) were measured 5, 20 and 60 rnin after induction of intracranial hypertension. The results confirm that the experimental situation gives a reproducible increase in ICP (25–28 mm Hg) and that the physiological variables remain stable during the period of intracranial hypertension. We conclude that the model simulates the effects of an acute intracranial focal mass and is well suited for the evaluation of different pharmacological therapies of increased ICP.
Respiratory changes during treatment of postoperative pain with high dose transdermal fentanyl
Authors: Bülow H. H. , Linnemann M. , Berg H. , Lang‐Jensen T. , LaCour S. , Jonsson T.
Published: January 2009

This study made a longterm (72 hours) evaluation of the efficacy and possible side‐effects of transdermal delivery of fentanyl (TTS‐system) for post‐operative pain relief.

The study was double‐blind, placebo‐controlled with either a TTS‐system delivering fentanyl 100 μg · h‐1 and rescue analgesic on demand or a placebo system and analgesic on demand. Analgesic consumption, pain, general satisfaction, respiratory rate, and levels of SpO2 and tcCO2 (pulse oximetry and transcutaneous CO2 measuring) were evaluated. Recruitment was stopped after enrolment of 24 patients, on safety grounds. The Fentanyl group was more satisfied with postoperative pain relief (P= 0.008); they had a lower analgesic demand (P<0.05) but also a lower respiratory rate (P<0.05) and a higher level of tcCO2 23 hours after application (P<0.05).

There were three cases (25%) of increased PaCO2 (>6.5 kPa) in the Placebo group but without low PaO2 levels, sedation or bradypnoea. Conversely, there were three cases (33%) in the Fentanyl group with bradypnoea (<10 breaths/minute), two without influence on PaO2 or PaCO2, but one (no. 24) with bradypnoea, heavy sedation, a marked decrease in PaO2 (5.8 kPa) and increased PaCO2 (7.5 kPa). These findings terminated the study. The 100 μg transdermal fentanyl system is agreeable to the patients, but apparently too potent for routine postoperative pain relief due to a risk of respiratory depression. Respiratory frequency can not be relied upon as sole indicator of insufficient respiration.
Disturbance of hepatocellular integrity associated with propofol anaesthesia in surgical patients
Authors: Tiainen P. , Lindgren L. , Rosenberg P. H.
Published: January 2009

Propofol anaesthesia has not been associated with any hepatic consequences. We used glutathione transferase Alpha (GSTA), a very sensitive indicator of hepatocellular integrity, to evaluate the effect of propofol on the liver. Total intravenous anaesthesia was induced and maintained with propofol without any supplements in 30 female patients undergoing breast surgery. Ten healthy female volunteers given the lipid vehicle of propofol served as controls. Serum GSTA concentration was measured with a sensitive time‐resolved immunorluorometric assay. Total intravenous propofol anaesthesia was stable and postoperative nausea negligible. A significant increase in GSTA from 3.1 μg · 1 ‐1 (mean baseline) to 10.0 μg · 1 ‐1 (mean peak) was noted after propofol infusion, indicating subclinical disturbance in hepatocellular integrity. No change in aminotransferases and no clinical signs of hepato‐toxicity were observed. A small increase in GSTA from 2.4 μg · 1‐1 (mean baseline) to 4.1 μg· 1‐1 (mean peak) was observed during lipid infusion.

We detected a subclinical disturbance in hepatocellular integrity after propofol anaesthesia for breast surgery. The mechanisms of hepatocellular impairment are not clear but the lipid vehicle of propofol alone does not explain it.
Morphine/prilocaine combination for intravenous regional anesthesia
Authors: Erciyes N. , Aktürk G. , Solak M. , Dohman D.
Published: January 2009

In this study we aimed to investigate clinically whether morphine acts on the peripheral nervous system directly. Twenty adult patients, who were scheduled for upper extremity surgery under tourniquet, had intravenous regional anesthesia. They were divided into two groups: one group was given 30 ml of 1% prilocaine plus 10 ml of 0.9% sodium chloride (P group) and the other group was given 30 ml of 1% prilocaine plus 6 mg morphine sulfate in 10 ml of 0.9% sodium chloride (P/M group). The onset of analgesia and anesthesia and recovery from anesthesia and analgesia were investigated in both groups. In the P/M group, the onset of analgesia and anesthesia was statistically faster and the recovery from anesthesia and analgesia was statistically slower than in the P group (P<0.05). We conclude that morphine is clinically effective in the peripheral nervous system at this dosage range.
Antiarrhythmic effects of magnesium sulphate. Report of three cases
Authors: Knudsen K. , Abrahamsson J.
Published: January 2009

A wide variety of antiarrhythmic agents is used in treatment of both supraventricular and ventricular arrhythmias. Magnesium sulphate has previously been used mainly in the treatment of torsade de pointe arrhythmias but several reports show that this agent may be used in the treatment of arrhythmias of different aetiology. We describe 3 patients who exhibited arrhythmias affecting haemodynamic performance. Case #1 had a subarachnoid haemorrhage and developed a supraventricular tachycardia. In case #2, ventricular tachycardia appeared during the postoperative course after abdominal surgery. Case #3 experienced critical heart failure due to dilated cardiomyopathy and had an irregular heart rhythm with multiple ectopic beats. In all three cases the administration of intravenous magnesium sulphate was successful in treating the arrhythmias. Magnesium sulphate is an antiarrhythmic agent that is effective mainly in treatment of ventricular arrhythmias. The drug can also be employed as second‐line treatment of supraventricular arrhythmias.
Transpulmonary disposition of prilocaine, mepivacaine, and bupivacaine in humans in the course of epidural anaesthesia
Authors: Kietzmann D. , Foth H. , Geng W.P. , Rathgeber J. , GundertRemy U. , Kettler D.
Published: January 2009

The pulmonary first‐pass kinetics of the amide‐linked local anaesthetics prilocaine, mepivacaine and bupivacaine were studied in 33 patients after a single epidural injection. Drug concentrations were monitored before and after lung passage, i.e. in samples withdrawn simultaneously from mixed venous and arterial blood. In most cases, maximum plasma concentrations were observed 10 min after injection (range 2 to 30 min). Two min after injection the local anaesthetics were distinctly extracted by the lung (prilocaine 40%, mepivacaine 20%, and bupivacaine 12%). Prilocaine was retained by the lung more effectively than bupivacaine and mepivacaine. However, a transpulmonary concentration gradient could be observed only for a short time, i.e. maximum 15 min. Altogether, in the case of accidental fast absorption, e.g. inadvertent intravenous injection, arterial peak concentrations of these drugs will be attenuated by passage of the lung. However, the lung will not substantially lower the risk of toxicity by amide‐linked local anaesthetics during normal conditions of regional anaesthesia where slow absorption occurs.
The influence of aging on skin temperature and hemodynamic changes during spinal anesthesia
Authors: HiroseM.D. M. , Chun T.‐Y. , Tobita M. , Muramatsu K. , Hara Y.
Published: January 2009

We investigated the influence of aging on the relationship between arterial pressure and skin temperature as a simple and indirect indicator of cutaneous blood flow. Sole and palm skin temperatures, sublingual temperature, heart rate, mean arterial blood pressure (MAP), and the anesthetic level as determined by cold discrimination, were measured before and during minor surgery under spinal anesthesia in patients aged under 65 years (young group) and above 65 years (elderly group). The sole skin temperature (Tsole) started to increase in the young group whose anesthesia level reached above L1‐L2, and approached the sublingual temperature in those whose anesthesia level reached above T8‐T10 after spinal injection. There was, however, no relationship between the anesthesia level and Tsole in the elderly group. There was a significant linear correlation between the decrease in MAP and the increase in Tsole in the young group. The change in Tsole was less in elderly patients than that in young patients with the same decrease in MAP. These findings suggest that a decrease in peripheral resistance may not be the main cause of hypotension during spinal anesthesia in elderly patients.
Reversal of atracurium‐induced neuromuscular block in paediatric patients
Authors: KirkegaardNielsen H. , Meretoja O. A. , Wirtavuori K.
Published: January 2009

We studied the efficacy of neostigmine and edrophonium to reverse an atracurium‐induced 90% neuromuscular block in 80 paediatric patients anaesthetized with thiopentone, fentanyl and nitrous oxide. The patients were divided into five age groups: 0–2 months, 3–11 months, 2–5 years, 6–10 years, and 11–15 years. At the end of surgery, the neuromuscular block was randomly antagonized with either neostigmine 50 μg kg‐1 with atropine 20 μg kg‐1 or with edrophonium 1 mg kg‐1 with atropine 10 μg kg‐1. In general, the first EMG response and train‐of‐four (TOF) ratio recovered fastest in the youngest age groups following either reversal agent (P<0.05). However, in each age group edrophonium had a faster onset of effect than neostigmine (P<0.05) even though a greater TOF‐ratio was finally reached with neostigmine. The effects of neostigmine were less variable and more predictable than those of edrophonium. Therefore, we recommend the use of neostigmine for routine paediatric practice.
Effects of dihydroergotamine on cerebral circulation during experimental intracranial hypertension
Authors: NilssonM.D. F. , Messeter K. , Grände P.‐O. , Rosén I. , Ryding E. , Nordström C.‐H.
Published: January 2009

Different cerebral vasoconstrictors have recently been suggested for the treatment of raised intracranial pressure (ICP) in patients with severe traumatic brain lesions. Such treatment may be associated with severe side effects. A porcine model simulating an intracranial mass lesion was utilized to examine the haemodynamic cerebral effects of dihydroergotamine (DHE), a recently introduced pharmacological treatment for raised intracranial pressure. Intracranial hypertension was induced by inflation of two tonometric gastric balloons placed extradurally covering the parieto‐occipital region bilaterally. The animals were randomized into one group with six animals receiving 1.0 mg of DHE i.v. followed by a continuous infusion of 0.2 mg/h (high dose) and another group of six animals receiving 0.15 mg i.v. followed by 0.03 mg/h (low dose). Measurements of cerebral blood flow (CBF) and arterio‐venous difference in oxygen content (Cavo2) were performed 5, 20, and 60 min after the DHE infusion. Intracranial pressure (ICP), mean arterial blood pressure (MAP) and cerebral electrical activity (EEG) were recorded continuously.

In both groups infusion of DHE caused a lasting decrease in ICP probably achieved mainly by a decrease in cerebral blood volume due to constriction of both arterial and venous capacitance vessels. In the group treated with high‐dose DHE, but not in that given low‐dose DHE, a progressive increase in Cavo2, a fall in jugular venous pH and an increase in EEG delta activity were observed indicating cerebral hypoxia. The study supports the view that DHE may be a valuable tool in the pharmacological treatment of increased ICP in traumatic brain lesions but underscores the importance of a proper dosage.
Cerebral haemodynamic effects of dihydroergotamine in patients with severe traumatic brain lesions
Authors: Asgeirsson B. , Grande P. O. , Nordström C. H. , Messeter K. , Sjöholm H.
Published: January 2009

Dihydroergotamine (DHE) is used in our recently introduced therapy of post‐traumatic brain oedema and is suggested to reduce ICP through reduction in both cerebral blood volume and brain water content. This study aims at increasing our knowledge of the mechanisms behind the ICP reducing effect of DHE by analysing cerebrovascular effects of a bolus dose of DHE in severely head injured patients (GCS<8). Mean hemispheric cerebral blood flow (CBF) calculated from the clearance of i.v. 133Xenon, ICP, and cerebral arterio‐venous difference in oxygen content (AVDO2), were measured before and after hyperventilation and after a bolus dose of DHE (4 μg/kg). The patients were divided into two groups, one with preserved and one with impaired cerebrovascular CO2‐reactivity to hyperventilation, the latter being predictive of poor outcome. The haemodynamic effects of DHE were compared to those of hyperventilation. Regional CBF and brain volume SPECT measurements were performed in two patients.

DHE increased cerebrovascular resistance (CVR) by about 20% and significantly reduced ICP in both groups of patients, resulting in unchanged AVDO2. Hyperventilation with preserved CO2‐reactivity caused a similar decrease in ICP as by DHE but with a much larger increase in CVR (by 70%) and a substantial increase in AVDO2. Hyperventilation with impaired CO2‐reactivity reduced ICP but otherwise had no significant cerebrovascular effects.

The study supports the concept that the ICP reducing effect of DHE results more from constriction of the large veins than from arterial vasoconstriction, also implying a relatively smaller risk of ischaemia with DHE than with hyperventilation.
Peripheral blood flow in the elderly during inhalational anaesthesia
Authors: Dwyer R. , Howe J.
Published: January 2009

We investigated whether aging altered the peripheral vascular effects of inhaled anaesthetic agents. Forearm blood flow (FBF) was measured in 20 young (18–34 yrs) and 21 healthy elderly (60–79 yrs) patients receiving isoflurane or halothane with 66% nitrous oxide (N2O) in oxygen (O2). After etomidate 0.3 mg/kg and vecuronium 0.1 mg/kg, the trachea was intubatcd and controlled ventilation instituted with 66% N2O in O2. Halothane or isoflurane were administered to achieve end‐tidal concentrations of 0.5% halothane or 0.9% isoflurane after 20 min. FBF was measured by venous occlusion plethysraography during the 20 min study period. Induction of anaesthesia with etomidate decreased FBF below baseline (awake) values in both elderly and young; intubation returned FBF to baseline values in the young but not in the elderly. FBF decreased below baseline values in young and elderly patients receiving halothane and in elderly patients receiving isoflurane but not in young patients receiving isoflurane. FBF was significantly greater in young patients receiving isoflurane than halothane after 20 min administration.

We conclude that perfusion of forearm muscle and skin is maintained in the young but not in the elderly during anaesthesia with isoflurane/N2O. Perfusion of forearm muscle and skin decreases in both young and elderly patients during anaesthesia with halothane/N2O. The cardiovascular effects of isoflurane/N2O and halothane/ N2O did not differ significantly in healthy elderly patients.
Oxygen tension‐associated changes on secondary immune response in halothane or isoflurane anesthetized mice
Authors: Puig N. R. , Elena G. A. , Barragán J. , Comba J. O. , Amerio N.
Published: January 2009

The impact that reexposure to anesthetics delivered in 100% oxygen or in synthetic air (21% oxygen/79% nitrogen) has on the secondary humoral immune response to sheep red blood cells was studied. Mice were immunized twice with a 15‐day interval and anesthetized immediately after each antigenic challenge with 1.5% halothane or 1.5% isoflurane for 40 min. Halothane in oxygen resulted in increased numbers of IgG‐secreting cells (IgG‐SC), while halothane in air depressed the response when compared to control mice. In contrast, isoflurane vaporized in oxygen did not affect IgG‐SC numbers, while isoflurane given in air lowered the response. Furthermore, neither 100% oxygen, nor the stress of being in an anesthesia chamber breathing synthetic air for 40 min had any immunological effect in non‐anesthetized mice.

The inspired oxygen concentration during halothane or isoflurane anesthesia has an effect on the secondary immune response. The effect is different between halothane and isoflurane, possibly due to differences in the extent of their metabolic and pharmacodynamic properties.
Hemodynamic changes due to Trendelenburg positioning and pneumoperitoneum during laparoscopic hysterectomy
Authors: Hirvonen E. A. , Nuutinen L. S. , Kauko M.
Published: January 2009

More prolonged gynecological laparoscopic operations are being performed in recent years, and a steeper head‐down position is required. The early reports of hemodynamic changes during gynecologic laparoscopy are conflicting, and the effects of anesthesia, head‐down tilt and pneumoperitoneum have not been clearly separated. Invasive hemodynamic monitoring was carried out in 20 female ASA Class I‐II patients who underwent laparoscopic hysterectomy. Baseline measurements were made in the supine, supine‐lithotomy and Trendelenburg (25 30 degrees) positions in awake patients. Measurements were repeated in the supine‐lithotomy and Trendelenburg positions after induction of anesthesia, during laparoscopy 5 minutes after the beginning of peritoneal CO2‐insufflation (intra‐abdominal pressure 13–16 mmHg) and at 15‐minute intervals thereafter, after laparoscopy in the Trendelenburg and supine positions, after extubation and in the recovery room at 30‐minute intervals. Patients received balanced general anesthesia with isoflurane in 35% O2 in an oxygen/air mixture. End tidal PGO2 was maintained between 4.5–4.8 kPa (33—36 mmHg) by changing the minute volume of controlled ventilation.

The Trendelenburg position in awake and anesthetized patients increased pulmonary arterial pressures (PAP), central venous pressure (GVP) and pulmonary capillary wedge pressure (PCWP). These pressures increased further at the start of CO2‐insufflation, decreased towards the end of the laparoscopy and reached pre‐insufflation levels after deflation of pneumoperitoneum. The mean arterial pressure (MAP) increased at the beginning of laparoscopy in comparison with the pre‐laparoscopic values. Heart rate (HR) was quite stable during laparoscopy. The cardiac index (CI) decreased with anesthesia from 3.8 to 3.2 1 · min‐1 · m‐2 and further during laparoscopy to 2.7 1 · min‐1 · m‐2, returning to pre‐insufflation values soon after deflation. The stroke index (SI) changed in concert with the GI changes. The right ventricular stroke work index decreased during laparoscopy more than the left ventricular stroke work index. The right atrial pressure (GVP) exceeded the PCWP more often during laparoscopy than during any other phase of the procedure.

Anesthesia and the Trendelenburg position increased the CVP, PCWP and pulmonary arterial pressures and decreased cardiac output. Pneumoperitoneum increased these pressures further mostly in the beginning of the laparoscopy, and cardiac output decreased towards the end of the laparoscopy. The risk of systemic CO2‐embolus was increased during laparoscopy.
Effects of temperature on somatosensory evoked potentials during open heart surgery
Authors: Yang L.‐C. , Jawan B. , Chang K. K.‐A. , Lee J. H.
Published: January 2009

Somatosensory evoked potentials (SEPs) have been found to be useful for early detection of brain ischemia during hypothermic cardiopulmonary bypass in cardiac surgery. However, the relationship between temperature and latency period remains unclear. We prospectively analyzed SEPs obtained during hypothermic cardiopulmonary bypass in 20 patients who had valvular replacement.

We concluded that i) a linear correlation was found between temperature and latency period during cooling and rewarming, ii) no hysteresis effect existed in cooling and rewarming, iii) there was a greater hypothermic effect on the synaptic transmission than on the conduction velocity, and, iv) age had also more profound effect on relationship between temperature and latency of SEPs.
Increase of Interleukin‐6 plasma concentrations and HLA‐DR positive T‐lymphocytes after hypotensive anaesthesia with sodium nitroprusside
Authors: Heesen M. , BachmannMennenga B. , Zeiler D. , Mahler M. , Hempelmann G.
Published: January 2009

Interleukin‐6 (IL‐6), a cytokine involved in the pathogenesis of sepsis and septic shock, and lymphocyte subpopulations were measured in blood circulation of patients receiving sodium nitroprusside (SNP) for induction of hypotension. The aim of this study was to evaluate whether this procedure influences distribution of lymphocyte subsets and IL‐6 response.

30 patients of ASA physical status I and II scheduled for nose‐septum correction were randomly assigned to the SNP‐ or control group (without SNP). Patients were anaesthetized with fentanyl, etomidate and isoflurane in 66% nitrous oxide. SNP was administered continuously during 60 min and mean arterial blood pressure was reduced to 50 mmHg. Before and after induction of anaesthesia, 60 min after the beginning of the operation (end of SNP‐infusion) and on the first postoperative day, IL‐6 plasma concentrations were determined by ELISA. The percentages of B‐, T‐lymphocytes, T‐helper, T‐suppressor cells and HLA‐DR positive (activated) T‐lymphocytes were examined by direct immunofluorescence using monoclonal antibodies.

On the first day after surgery IL‐6 plasma concentrations were significantly elevated in the SNP‐group compared to preoperative values. In this group the values were higher than in control patients [30.5 (10.9–47.5) pg/ml vs. 17.4 (8.5 21.5) pg/ml]. The percentage of HLA‐DR positive T‐cells was 25.8±4.9% in the patients with SNP on the first postoperative day; it was significantly higher than in control patients [16.5±3.7%]. We conclude that SNP‐administration increases percentage of activated T‐cells and IL‐6 secretion.
The effects of multiple small doses of exogenous surfactant on experimental respiratory failure induced by lung lavage in rats
Authors: Alvarez F. J. , Alfonso L. F. , Gastiasoro E. , Lopez‐Heredia J. , Arnaiz A. , Valls‐i‐Soler A.
Published: January 2009

Aim:To test the effect on pulmonary gas exchange and mechanics of multiple small doses of exogenous surfactant as an alternative to bolus delivery in experimental respiratory failure induced by lung lavage.

Methods:After anesthesia, tracheostomy and constant volume ventilation, respiratory failure was induced by lung lavage in 20 rats. Animals were randomly assigned to an untreated control group or two experimental groups. Equal total doses of modified porcine surfactant (200 mg ·kg‐1 body weight,) were given by tracheal instillation, either as a single bolus or in four (50 mg·kg‐1 b.w.) fractional doses at 10‐min intervals. Arterial pH and blood gases, and peak inspiratory pressure (PIP) were measured.

Results:After lavage, a rapid decrease in arterial pH and PaO2, and an increase in PaCO2 and PIP were observed in all animals. In both surfactant‐treated groups, PaO2 increased after surfactant instillation, and remained significantly higher than controls throughout the experiment. Arterial pH was significantly higher and PaCO2 significantly lower only in the single bolus group. In the multiple dose group, these levels were similar to those of controls.

Conclusions:In surfactant‐depleted rats with respiratory failure, instillation of four fractional surfactant doses did not result in the same enhancement on gas exchange and PIP, in the following 60 min, as same total dose given by a single bolus.
Effect of intravenous ketoprofen on pain after outpatient laparoscopic sterilisation
Authors: Eriksson H.
Published: January 2009

The effect of intravenous ketoprofen in reducing pain after laparoscopic sterilisation was studied in a placebo controlled, randomised setting in 100 patients undergoing outpatient laparoscopic sterilisation. The study group received 100 mg ketoprofen i.v. 2 min prior to induction of anaesthesia and an additional 100 mg was infused in 60 min. The control group received saline. Postoperative pain was assessed by verbal ratings and Visual Analogue Scale (VAS) (0–100 mm) and pain medication was standardised. Achievement of toleration of oral fluids, walking and voiding were assessed as parameters of home readiness. Pain during the first three postoperative days was assessed by a postal follow‐up questionnaire. After awakening the patients in the ketoprofen group had significantly (P<0.05) less pain [median VAS 25 (range 8–80) mm compared to the control group 41 (0–87) mm]. A 30% reduction in fentanyl requirement was seen in the study group [median 0.1 (range 0–0.3) mg] compared to the control group [0.15 (0.05–0.35) mg] in the postanaesthesia care unit (P<0.05). Furthermore, significantly (P<0.05) less paracetamol was needed in the study group in the Phase II recovery room. The results suggest that patients given ketoprofen have less pain upon awakening and need fewer analgesics for postoperative pain after laparoscopic sterilisation when compared to patients given saline. However, overall pain after awakening or time to home readiness did not differ between the groups.
The treatment of postanaesthetic shivering: a double blind comparison between alfentanil and pethidine
Authors: Lyons B. , Carroll M. , McDonald N. J.
Published: January 2009

It has been postulated that pethidine may mediate its effects on postanaesthetic shivering (PAS) via kappa‐opioid receptors. However, clinical evidence indicates that alfentanil, a pure ma‐agonist, may also have beneficial effects on PAS. In order to assess whether opioid effects on PAS are effected via kappa receptors, fifty‐one patients were randomised to receive alfentanil 250 μg (n=18), pethidine 25 mg (n=18) or placebo (n=15) on a double‐blind basis for the treatment of established postanaesthesia shivering (PAS). Both drugs proved significantly better in treating PAS than placebo (P<0.005). Following treatment, blood pressure fell and oxygen saturation increased in patients in the two treatment groups when compared with the control group (P<.05). There was a highly significant incidence of reshivering in the alfentanil treated group (P<0.005). In conclusion, the high incidence of reshivering indicates that alfentanil is unlikely to supercede pethidine in the treatment of PAS, but its initial success rate implies that pethidine's anti‐shivering effect is unlikely to be mediated via kappa‐opioid receptors.
Premedication with promethazine and transdermal scopolamine reduces the incidence of nausea and vomiting after intrathecal morphine
Authors: Tarkkila P. , Törn K. , Tuominen M. , Lindgren L.
Published: January 2009

Intrathecal morphine provides effective postoperative pain relief in major orthopaedic surgery. Its use, however, is associated with unpleasant side effects like nausea and vomiting. The effect of different premedications on postoperative emetic sequelae induced by intrathecal morphine was studied in a prospective, double blind study. Sixty patients scheduled for arthroplasty surgery of the lower extremity were anaesthetized with spinal anaesthesia with a combination of isobaric bupivacaine 20 mg and morphine 0.3 mg. For premedication the patients were randomised to three groups of equal size. They received either oral diazepam (5 15 mg), oral promethazine (10 mg) or a combination of promethazine and transdermal scopolamine (1.5 mg).

Sixty percent of the patients with both promethazine and transdermal scopolamine were totally free from postoperative nausea and vomiting (PONV) symptoms compared to those premedicated with diazepam (40%) or promethazine alone (30%). Promethazine together with transdermal scopolamine reduced significantly the number of patients with vomiting (to 25%) and also vomiting episodes. This combination was also more efficient in reducing the incidence of nausea (to 25%) and nausea episodes than promethazine alone (P<0.05). Combination also reduced the requests for additional pain relief (P<0.05). PONV occurred in a majority of patients during the first 12 hours of the 24 hour study period and the need for additional analgesics thereafter. The incidence of itching (50–65%) and urinary catheterisation (55–70%) was similar in all groups.

In conclusion, the combination of oral promethazine and transdermal scopolamine was most effective in reducing PONV symptoms and also reduced the need for postoperative pain treatment.
Repetitive hearing loss following dural puncture treated with autologous epidural blood patch
Authors: Lybegker H. , Andersen T.
Published: January 2009

A case of repetitive hearing loss following an otherwise uncomplicated diagnostic dural puncture is presented. The patient developed severe postdural puncture headache (PDPH) and three episodes of pronounced vestibulocochlear disturbances within five weeks after only one dural puncture. On all three occasions the headache and the associated symptoms were treated with an autologous epidural blood patch (AEBP) resulting in the immediate disappearance of all the subjective complaints of postdural puncture headache and the normalization of an audiological test within minutes.
Post dural puncture headache
Authors: McSwiney M. , Phillips J.
Published: January 2009

We describe the delayed diagnosis and management of a spinal headache following the use of a 24 g Sprotte needle, the results of a survey of spinal needle usage by physcians in the south west of England and a review of the prevention and management of postdural puncture headache.
Dose‐response relationship for mivacurium inpatients with phenotypically abnormal plasma cholinesterase activity
Authors: OSTERGAARD D. , JENSEN F. S. , SKOVGAARD L. THEIL , VIBY‐MOGENSEN J.
Published: January 2009

During thiopentone‐fentanyl‐nitrous oxide anaesthesia and using a cumulative design, we studied the dose‐response relationship of mivacurium in 8 patients: 7 patients phenotypically homozygous for the atypical plasma cholinesterase gene and 1 patient homozygous for the silent gene. The estimated mean ED50 and ED95 were 15 and 20 μg. kg. bw‐1 in patients homozygous for the atypical gene, and 13 and 16 μg. kg. bw‐1 in the patient homozygous for the silent gene, respectively. The results indicate that mivacurium is 4‐5 times more potent in patients homozygous for the atypical or the silent gene than in patients with normal plasma cholinesterase activity and phenotype.
Effect of succinylcholine on subsequently administered mivacurium in children
Authors: JALKANEN L. , MERETOJA O. A. , TAIVAINEN T.
Published: January 2009

The interaction between mivacurium and succinylcholine when mivacurium was administered during the early recovery from succinylcholine block was studied in 30 children 2‐12 years of age anaesthetized with propofolalfentanil‐N2O‐O2. Neuromuscular response was monitored by adductor pollicis EMG. Fifteen patients received 200 μg. kg‐1 of mivacurium (Group M), and another fifteen received 1500 μg. kg‐1 of succinylcholine followed by 200 μg. kg‐1 of mivacurium when the first EMG response recovered to 5% of calibration value (Group SchM). Plasma cholinesterase (pChE) activity was normal in each patient. The recovery times following mivacurium did not differ between the two groups. Times required for recovery of the first EMG response from 25 to 75% of full EMG recovery were 3.6±1.0 (mean±SD) and 4.0±0.7 min for the Groups M and SchM, respectively. The time from administration of mivacurium to the recovery of train‐of‐four ratio 0.70 was 13.2±3.3 min for the Group M and 13.6±3.1 min for the Group SchM (NS). Thus, in patients with normal pChE activity preceding administration of succinylcholine did not influence the recovery of neuromuscular function from subsequent mivacurium.