bluuebunny/crossref_metadata_2025 huggingface dataset:
Removal of halogenated anaesthetics from a closed circle system with a charcoal filter
Authors: Larsen V. Højkjær , Severinsen I. , Waaben J.
Published: January 2009

Halogenated anaesthetics may be removed from a closed circle system by means of a charcoal filter. With this technique dispersion to the atmosphere and a possibly destructive effect of the halogenated volatiles on the protective layer of ozone is avoided. Removal of halothane or isoflurane with a charcoal filter was studied in a closed circle system connected to an artificial lung. The concentration of anaesthetic (C1) was recorded in relation to time by an anaesthetic gas monitor interposed between the system and the lung at ventilations of 3, 5, 7 or 9 1/min (v̇). Based on theoretical considerations, it was expected that C1 = C0 · exp (‐ v̇/V · t), (V: volume of the system). Analysis of regression demonstrated that the results fitted well to an exponential decrease (R2 > 0.94) and the downslope increased with increasing rate of ventilation. However, the slopes deviated significantly from the theoretically predicted slopes, possibly because of adsorption to hoses and bags and unequal distribution of the volatiles in the system. Halothane was eliminated more slowly than isoflurane. This study demonstrates that halogenated volatiles are eliminated in an exponential way following charcoal filtration and the rate depends on the ventilation and type of volatile.
Cortisol deficiency in metomidate anesthetized bacteremic pigs: results in circulatory failure — beneficial effect of cortisol substitution
Authors: Neumann R. , Worek F. S. , Blümel G. , Zimmermann G. J. , Fehm H. L. , Pfeiffer U. J.
Published: January 2009

Etomidate and the closely related metomidate are known to inhibit cortisol synthesis. We studied the influence of metomidate on hemodynamic performance and survival time of bacteremic pigs. Thirty pigs, 30.2±0.8 kg, were anesthetized with intravenous metomidate (2.5 mg· kg‐17· h‐1) plus ketamine (3.0 mg · kg‐1· h‐1), and were then mechanically ventilated. The animals were randomly allocated to three groups of 10 pigs each. Group A received an infusion of livePseudomonas aeruginosabacteria (2.5 · 109· kg‐1· h‐1organisms until death), Group B additionally received a bolus of 1 mg · kg‐1cortisol (followed by an infusion of 0.1 mg · kg‐1· h‐1) starting 1 h prior to the bacterial infusion, and Group C served as anesthesia control without receiving bacteria or cortisol. The experiments in Group C were terminated after 10 h. In Group A the cortisol level was severely suppressed from the very beginning. The animals died of circulatory failure after 4.3 ± 0.4 h. In contrast, Group B exhibited fairly stable hemodynamics, but the animals died due to pulmonary edema after 11.1 ± 1.3 h. Cortisol deficiency in metomidate anesthetized pigs facilitates the development of circulatory failure in the course ofPseudomonasbacteremia, which does not occur if cortisol is infused to reconstitute a physiological level. However, this cortisol substitution did not prevent the development of pulmonary edema caused byPseudomonas aeruginosa. Possible mechanisms of the deleterious effect of cortisol deficiency and implications in regard to the clinical use of metomidate/etomidate are discussed.
The effects of bupivacaine and pipecoloxylidide on platelet functionin vitro
Authors: Odoom J. A. , Sturk A. , Dokter P. W. C. , Bovill J. G. , Cate J. W. ten , Oosting J.
Published: January 2009

The influence of bupivacaine and its major metabolite, pipecoloxylidide, on human platelet function was studiedin vitro. Significant inhibition of ADP and collagen‐induced platelet aggregation occurred only with concentrations of bupivacaine above 10 μg · ml‐1. This concentration (10–25 μg · ml‐1) is much higher than would be expected in routine clinical use of bupivacaine for epidural analgesia. The inhibition of platelet aggregation was associated with a significant decrease in β‐thromboglobulin secretion. In contrast, pipecoloxylidide had no effect on platelet aggregation or the β‐thromboglobulin release. We conclude that the previously reported 30‐min time‐lag between the maximal plasma concentration of bupivacaine and the inhibition of platelet aggregation is unlikely to be due to a metabolism of bupivacaine to pipecoloxylidide.
Pain relief following herniotomy: a double‐blind randomized comparison between naproxen and placebo
Authors: Dueholm S. , Forrest M. , Hjortsø E. , Lemvigh E.
Published: January 2009

Sixty consecutive out‐patients were randomly assigned to have either a non‐steroid anti‐inflammatory drug (naproxen 500 mg) or an identical placebo administered as suppositories half an hour before unilateral herniotomy. Within 1.5 h after the end of surgery, pain scores were significantly improved in patients receiving naproxen (P<0.02). The long‐term analgesic effect was measured indirectly by registering the postoperative requirement for supplementary analgesic doses of acetylsalicylic acid 1 g plus codeine 20 mg. The time elapsing before the first demand for additional analgesics was prolonged by median 1.5 h, and the need for further analgesic treatment during 24 h was significantly reduced (P< 0.003) in the naproxen group (median, 2 doses) compared to the placebo group (median, 4 doses). No statistically significant difference was found between the groups with regard to the occurrence of side‐effects.
Is epidural anaesthesia using bupivacaine safe in patients with atrio‐ventricular conduction defects?
Authors: Eledjam J. J. , Coussaye J. E. de La , Colson P. , Viel E. , Bassoul B. , Bertinchant J. P. , D'Athis F.
Published: January 2009

Bupivacaine is known to interact with the conductive system of the heart, also when used in epidural anaesthesia. Ten patients, undergoing bupivacaine epidural anasthesia for lower limb or pelvic surgery, who presented a history of cardiac conduction disturbances, were studied. The ECG was continuously monitored and a right ventricular bipolar electrode was used to monitor the following parameters: heart rate, QRS duration, QT, Atria‐His and His‐Ventricle intervals. No significant change was noticed, even in patients with a high grade conduction defect. The mean plasma level of bupivacaine was 0.33 ± 0.23 μg/ml. Based on this experience, it seems that lumbar epidural anaesthesia with bupivacaine can be safely used in patients with asymptomatic AV conduction abnormalities.
Influence of propranolol on the in vitro response to caffeine and halothane in malignant hyperthermia‐susceptible muscle
Authors: ØRding H.
Published: January 2009

In vitro contracture tests for susceptibility to malignant hyperthermia (MH) were performed with halothane and caffeine in 27 patients according to the protocol of the European MH Group. Additional halothane and caffeine tests were performed in the presence of propranolol 80 μg/l. Contractures after exposure to halothane were seen only in MH‐susceptible (MHS) patients (n= 12), and were not affected by propranolol. In contrast, propranolol shifted the caffeine dose‐response curve to the right and significantly increased the caffeine threshold in the MHS group. Propranolol did not influence the caffeine results in the normal response group group (n = 12). It is concluded that 43‐blockers should be discontinued before investigation for MH susceptibility.
The effects of local anesthetics on maternal and neonatal platelet function
Authors: Grant G. J. , Ramanathan S. , Patel N. , Turndorf H.
Published: January 2009

The effects of bupivacaine (B), lidocaine (L) and 2‐chloroprocaine (C) on maternal (M) and neonatal (N) platelet function were studied usingin vitroβ‐thromboglobulin (β‐tg) release (radioimmunoassay), andin vitroplatelet aggregation. Aggregation produced by adenosine diphosphate (ADP), epinephrine and collagen was measured in the presence of 1, 10, 100, 500 or 1000 μg/ml concentrations of B, L or C. In addition, spontaneousin vivoβ‐tg release was measured in M and N blood.In vivoβ‐tg level in M and N blood was approximately double that in non‐pregnant subjects (p<0.025).In vitroβ‐tg release in M and N samples was inhibited only at concentrations exceeding 1000 μg/ml, and the inhibition was less in M and N samples than in non‐pregnant subjects. None of the anesthetics inhibited aggregation of M or N platelets at 1 and 10 μg/ml. Only concentrations of 500 μg/ml or greater consistently inhibited platelet aggregation produced by the three aggregants in M and N samples, and L was the least effective of the three agents. Neonatal platelet aggregation was affected more by local anesthetics than was maternal aggregation. It is concluded that plasma local anesthetic concentrations achieved during normal maternal epidural anesthesia do not affect M or N platelet aggregation or β‐tg release.
Adverse effects on the brain in connection with isoflurane‐induced hypotensive anaesthesia
Authors: Enlund M. , Ahlstedt B. , Revenäs B. , Krekmanov L. , Ronquist G.
Published: January 2009

As a marker of brain cell injury, adenylate kinase (AK) was measured in cerebrospinal fluid (CSF) in 10 patients given anaesthesia with isoflurane‐induced hypotension for corrective surgery of dentofacial deformities. Nine out of 10 patients displayed a marked increase in CSF‐AK postoperatively compared with preoperative values. The postoperative mean value displayed a 400% increase compared to the corresponding preoperative value. This difference was statistically significant (P=0.001). The rise in CSF‐AK was most probably the result of an enhanced efflux of AK into CSF subsequent to a presumed hypoxic injury to brain cells.
Constant‐flow ventilation in canine experimental pulmonary emphysema
Authors: Hachenberg T. , Wendt M. , Meyer J. , Struckmeier O. , Lawin P.
Published: January 2009

The efficacy of constant‐flow ventilation (CFV) was investigated in eight mongrel dogs before (control‐phase) and after development of papain‐induced panlobular emphysema (PLE‐phase). For CFV, heated, humidified and oxygen‐enriched air was continuously delivered via two catheters positioned within each mainstem bronchus at flow rates (V) of 0.33, 0.5 and 0.66 1/s. Data obtained during intermittent positive pressure ventilation (IPPV) served as reference. In the control‐phase, Pao2 was lower (P≤0.05) and alveolo‐arterial O2 difference (P(a‐a)O2 was higher (P≤0.01) during CFV at all flow rates when compared with IPPV. This may be due to inhomogeneities of intrapulmonary gas distribution and increased ventilation‐perfusion (Va/Q·) mismatching. Paco2 and V· showed a hyperbolic relationship; constant normocapnia (5.3 kPa) was achieved at 0.48 ± 0.21 1/s (≤5.3). Development of PLE resulted in an increase of functional residual capacity (FRC), residual volume (RV) and static compliance (Cstat) (P≤0.05). Pao2 had decreased and P(a‐a)O2 had increased (P≤0.05), indicating moderate pulmonary dysfunction. Oxygenation during CFV was not significantly different in the PLE‐phase when compared with the control‐phase. Paco2 and V· showed a hyperbolic relationship and V·5.3 was even lower than in the control‐group (0.42 ± 0.13 1/s). In dogs with emphysematous lungs CFV maintains sufficient gas exchange. This may be due to preferential ventilation of basal lung units, thereby counterbalancing the effects of impaired lung morphometry and increased airtrapping. Conventional mechanical ventilation is more effective in terms of oxygenation and CO2‐elimination.
Magnetic resonance imaging — a useful tool for airway assessment
Authors: Schneider M. , Probst R. , Wey W.
Published: January 2009

The case is presented of a 58‐year old man with a malignant non‐Hodgkin's lymphoma of the root of the tongue. Preoperative magnetic resonance imaging (MRI) proved extremely useful in the evaluation of the upper aerodigestive tract, by providing sagittal sections of the hypopharynx and the inlet of the larynx. Thus, a potentially difficult intubation was confirmed in a patient in whom other investigations would not have produced comparable conclusions. Difficulties in airway management were avoided by performing a tracheostomy under local anesthesia. This represents a novel application of MRI, which might contribute to the safety of airway management.
Serum CK‐MB is useful in diagnosis of acute myocardial infarction after total hip arthroplasty
Authors: ÅKeson J. , Boström P.‐Å. , Gustafson C. , Rosberg B.
Published: January 2009

Skeletal muscle trauma and myocardial infarction both increase the serum values of the creatine kinase isoenzyme MB (CK‐MB) which may render the diagnosis of perioperative myocardial infarction in major orthopaedic surgery more difficult. The significance of postoperative changes in CK‐MB was studied in 30 patients subjected to total hip replacement (THR), and the results were compared to CK‐MB in 30 non‐surgical patients with acute myocardial infarction (AMI). AMI patients had significantly higher serum CKMB values at 24 h than THR patients. However, the highest value after THR exceeded the lowest value in AMI. The results suggest that skeletal muscle release of CK‐MB after THR is slight. CK‐MB thus also seems useful in the diagnosis of AMI in postoperative patients.
Carbon dioxide distribution in Mapleson A and D systems: an experimental study
Authors: Andersen P. K. , Olsen J. E. , Jensen A. , Stokke D. B.
Published: January 2009

The distribution of CO2 in the Mapleson A and D rebreathing systems was investigated experimentally during controlled ventilation and with the expiratory valve closed during inspiration. Maximal and minimal levels of CO2‐concentration obtained from capnograms along the tubing were used to construct “gas profiles”. For both systems, high tidal volumes and low fresh gas flows resulted in a high degree of gas separation with a pool of alveolar gas near the expiratory valve, and longitudinal gas mixing was minimal. In this manner fresh gas loss was prevented and fresh gas utilization optimized. The end of the tubing nearest the patient was found to act as a reservoir for alveolar gas in the Mapleson A system and fresh gas in the Mapleson D system. Fresh gas utilization in the Mapleson D system was somewhat less efficient than in the Mapleson A system due to the fresh gas admixture to exhaled alveolar gas in the patient‐near end of the tubing during expiration. The replacement of the usual expiratory valve of the Mapleson A system by a valve which is closed during inspiration makes the A system an alternative to the D system for controlled ventilation.
Anesthesia with alfentanil and methohexitone for short gynecological surgery
Authors: Bernstein K. , Wirpszo R. , Djärv L.
Published: January 2009

An anesthetic technique in which alfentanil hydrochloride, an ultra‐short‐acting opioid, was used as a substitute for N2O/O2 was evaluated in outpatient gynecological surgery. Methohexitone was used as a hypnotic agent. The following parameters were studied: blood pressure (BP) and heart rate before, during and at the end of surgery; the incidence of apnea longer than 20 s at induction; the awakening phase; immediate postoperative complications and later postoperative complications according to a questionnaire, including signs of thrombophlebitis. Eighty‐nine patients were randomly allocated to three groups. Twenty‐nine patients received alfentanil 7 μg/kg plus methohexitone plus O2/air (Group A7). Thirty patients received alfentanil 15 μg/kg plus methohexitone plus O2/air (Group A15). Thirty patients received thiopentone 5 mg/kg plus N2O/O2 (Group P, reference group). Neither in the A7‐group, nor in the A15‐group was there any increase in peroperative BP, while in the P‐group both systolic and diastolic BP rose. The awakening phase was significantly shorter in both the A7‐ and A15‐groups compared to the P‐group. Apnea of clinical importance was only seen in the A15‐group. There were few immediate postoperative complications in all groups, but the incidence of dizziness was significantly higher in the P‐group. According to the questionnaire, the overall incidence of complaints the day after surgery was somewhat higher in the P‐group. On the other hand, there was a somewhat higher incidence of thrombophlebitis in both A‐groups. We may thus recommend the use of a combination of alfentanil 7 μg/kg plus methohexitone and air/oxygen for anesthesia in patients subjected to short gynecological procedures.
The effect of topically applied anaesthetics (EMLA® cream) on thresholds to thermode and argon laser stimulation
Authors: Arendt‐Nielsen L. , Bjerring P.
Published: January 2009

The cold and warmth thresholds to thermode stimulation and the sensory and pain thresholds to argon laser stimulation were determined before and after topical application of EMLA (Eutectic Mixture of Local Anaesthetics) cream. The sensory threshold to argon laser stimulation and warmth threshold to thermode stimulation are both described in terms of warmth or faint heat. The sensory threshold persisted for more than 80 min of EMLA application, whereas the warmth and cold thresholds were detectable after 105 min in half the volunteers. Pain evoked by strong laser pulses was abolished after 80 min of cream application. The analgetic effect of topically applied lidocaine/prilocaine, evaluated by the cutaneous thermal and pain threshold, is compatible with the idea that topical application of EMLA cream blocks free nerve endings rather than the nerve fibres, and induces a sequence of sensory loss which, in some respects, differs from that typically observed after perineural application of local anaesthetics. The effect of topically applied anaesthetics is influenced by a number of thermodynamical, anatomical, and physiological factors in the skin.
Computerised evaluation of the electrocardiogram during and for a short period after gall bladder surgery
Authors: Jakobsson J. , Rehnqvist N. , Davidson S.
Published: January 2009

Long‐term ECG recording on tape (LTER) was performed in 32 consecutive patients undergoing cholecystectomy. Twenty‐two of the patients recorded showed ST‐segment changes during the per‐ and early post‐operative period. ST‐segment depression was the most common change seen in 17 patients; however, 12 patients showed ST‐segment elevation. In only nine patients were the ST‐segment changes seen to be associated with major changes in pulse or blood pressure. ST‐segment changes were seen as frequently in patients with, as without, known cardiovascular disease. All patients had an uncomplicated postoperative course and no case of myocardial infarction was seen. ST‐segment changes during elective surgery seem to be a common phenomenon. The etiology of the observed changes is not clear and its value in the detection of per‐ or postoperative myocardial ischemia needs to be further evaluated.
Effects of dopamine on intestinal hemodynamics and motility during epidural analgesia in the cat
Authors: Lundberg J. , Biber B. , Delbro D. , Martner J. , Werner O.
Published: January 2009

The effects of dopamine on intestinal blood flow (IBF) and intestinal contraction rate (ICR), and on mean arterial pressure (MAP) and heart rate (HR) were studied in eight cats before and during epidural analgesia (EDA). Before EDA, dopamine 5 and 10 μg · kg‐1· min‐1had no effect on IBF, MAP and HR, but the higher infusion rate decreased ICR by 71 ± 19% (mean ± 1 s.e.mean) (P<0.01). EDA significantly increased IBF when intestinal arterial pressure was maintained at an unchanged level by means of a pump, and transiently increased ICR and intestinal tone, but reduced MAP by 46 ± 8% (139 ± 11 to 75 ± 9 mmHg,P< 0.01) and HR by 26 ± 3% (248 ± 7 to 184 ± 8 beats · min‐1,P< 0.01). During EDA, dopamine increased IBF further, the response being similar at both infusion rates. 5 μg · kg‐1· min‐1increased HR by 26 ± 7 beats · min‐1(P< 0.01) and MAP by 19 ± 9 mmHg (ns). The corresponding values at 10 μg · kg‐1· min‐1were 65 ± 14 beats · min‐1(P< 0.01) and 35 ± 8 mmHg (P<0.01), respectively. Vascular autoregulation appeared to be unaffected by dopamine and EDA. The effect of dopamine on ICR was not significantly different to what was seen before EDA. It is concluded that the effects of dopamine on IBF, MAP and HR were markedly different during EDA as compared to before the block and that ICR was reduced by dopamine, while it was transiently increased by EDA. The findings indicate that dopamine infusion is a useful way of supporting both the intestinal and the systemic circulation during EDA.
The cardiovascular effects of vecuronium during halothane anaesthesia
Authors: Kristensen J. , Helbo‐Hansen H. S. , Tuft P. , Hole P.
Published: January 2009

In a double‐blind, placebo‐controlled, prospective randomized trial in 70 otherwise healthy patients undergoing elective surgery of the thyroid gland, the breast, the inguinal canal or the lower limbs, we studied the cardiovascular effects of vecuronium during halothane‐nitrous oxide anaesthesia. Vecuronium was found to have no clinically significant influence on heart rate or mean arterial pressure, before or during surgery. Bradycardia was a rare event under the special conditions of the study design.
Indomethacin as an analgesic after hysterectomy
Authors: Engel C. , Lund B. , Kristensen S. S. , Axel C. , Nielsen J. B.
Published: January 2009

The influence of indomethacin on the need for postoperative analgesics was investigated in a double‐blind study of 41 patients scheduled for abdominal hysterectomy. The incidence of side effects was evaluated. The patients were randomly allocated to treatment with either indomethacin, 0.8 mg/kg i.v. preoperatively, followed by 100 mg rectally 8‐hourly for 3 days (Group I), or placebo (Group P), in both cases supplemented with nicomorphine as needed. Thiopentone was used for induction of anaesthesia, followed by nitrous oxide, enflurane, suxamethonium, and pancuronium. The average nicomorphine requirement during the study was 14.0 mg/24 h lower in Group I than in Group P. The pain score values were slightly lower in Group I when resting, but similar on movement. A significant increase in perioperative blood loss was found in Group I. Beginning the indomethacin treatment with a preoperative i.v. bolus seems to offer few advantages compared to a purely postoperative regime and may increase the risk of bleeding complications.
Glycopyrrolate: pharmacokinetics and some pharmacodynamic findings
Authors: Ali‐Melkkilä T. , Kaila T. , Kanto J.
Published: January 2009

In the present study, a sensitive and reproducible radioreceptor assay (RRA) was used to evaluate the basic pharmacokinetic properties of glycopyrrolate, a quaternary amine with peripheral antimuscarinic activity. Based on the plasma levels after a single intravenous injection, 6 μg/kg (n = 6), the distribution phase half‐life (2.22 ± 1.26 s.d. min) and the elimination phase half‐life (0.83 ± 0.29 h) of glycopyrrolate were short due to the low distribution volume during the elimination phase (0.64 ± 0.29 1/kg) and to the respectively high total plasma clearance value (0.54 ± 0.14 1/kg/h). An intramuscular injection, 8 μg/kg (n = 6), was followed by a fast and predictable systemic drug absorption and clinical effects (heart rate increase, dry mouth). In this group the time to maximum plasma concentration (tmax) was 27.48 ± 6.12 min and the maximum plasma concentration (Cmax) was 3.47 ± 1.48 μg/1. After oral drug intake, 4 mg (n = 6), an apparently low and variable gastrointestinal absorption was found (tmax = 300.0 ± 197.2 min, Cmax = 0.76 ± 0.35 μg/1), thus indicating that the oral route of drug administration is of no value as a routine premedication. The correlation between the plasma concentration of glycopyrrolate and the drug effects appears to be variable. Because of its sensitivity, the RRA method proved to be quite useful in evaluating the kinetics of glycopyrrolate and its relationship to various clinical effects.
Failure of a heat and moisture exchanger as a cause of disconnection during anaesthesia
Authors: Bengtsson M. , Johnson A.
Published: January 2009

Two cases of ventilator tubing mishaps, resulting from defective heat and moisture exchangers, are described. The report emphasises the need for preoperative inspection of the anaesthetic machine and associated equipment as well as the importance of a disconnect alarm device.
Indomethacin and the stress response to hysterectomy
Authors: Engel C. , Kristensen S. S. , Axel C. , Lund B. , Nielsen J. B.
Published: January 2009

The influence of indomethacin on the surgical stress response was evaluated in a double‐blind study of 20 patients, scheduled for abdominal hysterectomy. The patients were randomly allocated to treatment with either indomethacin, 0.8 mg/kg i.v. preoperatively followed by 100 mg rectally 8‐hourly for 3 days (Group I), or placebo (Group P), in both cases supplemented with nicomorphine as needed. Thiopentone was used for induction of anaesthesia, followed by nitrous oxide, enflurane, suxamethonium, and pancuronium. In both groups a significant increase in blood glucose and serum cortisol was seen postoperatively. Twenty‐four hours later the values had almost returned to baseline. No differences were found between the absolute increases in the two groups. In both groups the serum concentrations of C‐reactive protein, haptoglobin, and orosomucoid increased after an initial small decrease. We conclude that pathways involving prostaglandin synthesis play only a minor role in eliciting the postoperative hyperglycaemic, hypercortisolaemic, and acute phase protein response.
Plasma concentrations of atrial natriuretic factor during positive end‐expiratory pressure ventilation in dogs with normal or impaired left ventricular function
Authors: Hevrøy O. , Kløw N. E. , Forsdahl K. , Mjøs O. D.
Published: January 2009

The influence of positive end‐expiratory pressure (PEEP) ventilation on plasma concentrations of atrial natriuretic factor (ANF) was studied in dogs anesthetized with sodium pentobarbital during normal cardiac function and during acutely impaired left ventricular function. Left ventricular impairment was induced by injecting repeated doses of polystyrene microspheres with a diameter of 50 μm into the main left coronary artery, causing a severe depression of left ventricular performance. This was accompanied by doubling of ANF concentrations measured in blood sampled from aorta. Application of PEEP (10 cmH2O (0.98 kPa)) reduced plasma ANF in dogs both with normal and impaired left ventricular function. The decrease was significantly greater during left ventricular impairment compared to control, 31 and 19%, respectively. A positive correlation was observed between plasma ANF and transmural left ventricular end‐diastolic pressure when all data were pooled, but not between ANF and transmural right atrial pressure. This implies that transmural left ventricular end‐diastolic and hence transmural left atrial pressure probably is the principal determinant of acute ANF release in this model. Reduced plasma ANF in response to PEEP even during acute left ventricular impairment when ANF release was augmented, was probably due to diminished atrial distension during PEEP ventilation.
Effects of thoracic paravertebral block with bupivacaine versus combined thoracic epidural block with bupivacaine and morphine on pain and pulmonary function after cholecystectomy
Authors: Bigler D. , Dirkes W. , Hansen R. , Rosenberg J. , Kehlet H.
Published: January 2009

Twenty patients undergoing elective cholecystectomy via a subcostal incision were randomized in a double‐blind study to either thoracic paravertebral blockade with bupivacaine 0.5% (15 ml followed by 5 ml/h) or thoracic epidural blockade with bupivacaine 7 ml 0.5% + morphine 2 mg followed by 5 ml/h+ 0.2 mg/h, respectively for 8 h postoperatively. Mean initial spread of sensory analgesia on the right side was the same (Th3,4 – Th11 versus Th2,6–Th11), but decreased (P< 0.05) postoperatively in the paravertebral group. All patients in the epidural group had bilateral blockade, compared with three patients in the paravertebral group. In both groups only minor insignificant changes in blood pressure and pulse rate were seen postoperatively. Pain scores were significantly higher in the paravertebral group, as was the need for systemic morphine (P<0.05). Pulmonary function estimated by forced vital capacity, forced expiratory volume and peak expiratory flow rate decreased about 50% postoperatively in both groups. In conclusion, the continuous paravertebral bupivacaine infusion used here was insufficient as the only analgesic after cholecystectomy. In contrast, epidural blockade with combined bupivacaine and low dose morphine produced total pain relief in six of ten patients.
Transvenous retrieval of intracardiac catheter fragments
Authors: Lybecker H. , Andersen C. , Hansen M. K.
Published: January 2009

Six cases of catheter embolism are presented, and various techniques of retrieving these foreign bodies from the heart are described. The techniques may be carried out under local anaesthesia. They are rapid, safe and enable the patients to avoid thoracotomy.
Efficacy of high frequency ventilation combined with volume controlled ventilation in dependency of extravascular lung water
Authors: Zeravik J. , Pfeiffer U. J.
Published: January 2009

In a prospective study continuous positive pressure ventilation (CPPV) was compared with the combination of CPPV and high frequency ventilation (CHFV). Forty‐seven patients of a surgical intensive care unit who required mechanical ventilation were randomly assigned to a CHFV group (n = 27) or a control group with CPPV (n=20). Usual hemodynamic and oxygenation variables, intrathoracic blood volume (ITBV) and extravascular lung water (ETV) were assessed before and 6 h after switching to CHFV (CHFV group) or maintaining CPPV (control group). In both groups mean airway pressure (MPaw) was kept constant. The change of the respiratory index (dRI) was used for evaluation of the effect of the ventilation mode. A negative correlation was found between ETV and dRI (r= –0.67), which led to the conclusion that the height of ETV determines the efficacy of CHFV. In a CHFV subgroup with ETV > 15 ml/kg (n= 17), CHFV significantly improved Pao2/Fio2 (18.7 to 26.4 kPa), RI (4.44 to 2.99) and intrapulmonary shunt (33.5 to 27.5%) and slightly, but significantly impaired cardiac index (CI, 4.45 to 3.92 l/min · m2), stroke volume index (40.7 to 36.4 ml/m2) and pulmonary vascular resistance index (PVRI, 310 to 366 dyn · s · cm‐5 · m2), but oxygen delivery (Do2) remained almost unchanged. The CI decrease came about with an increase of PVRI on account of an increased lung volume under CHFV in this group. CHFV induced no significant effects in the subgroup with ETV < 15 ml/kg (n=10). There were no differences in any variable during CPPV between the CHFV subgroups and corresponding subgroups of the control group. In conclusion, ETV helps to identify patients in whom CHFV markedly improves oxygenation. In these patients CHFV also slightly decreases CI, if MPaw is kept constant. However, the CI decrease is outweighed by the improvement of oxygenation, as Do2 remains unchanged.
Isoflurane or halothane for cesarean section: comparative maternal and neonatal effects
Authors: Abboud T. K. , D'Onofrio L. , Reyes A. , Mosaad P. , Zhu J. , Mantilla M. , Gangolly J. , Crowell D. , Cheung M. , Afrasiabi A. , Khoo N. , Davidson J. , Steffens Z. , Zaki N.
Published: January 2009

The maternal and neonatal effects of isoflurane and halothane combined with 50% N2O – 50% O2 were compared in 60 healthy parturients undergoing primary or repeat cesarean section. All patients had rapid sequence induction of anesthesia with sodium thiamylal 4 mg/kg followed by succinylcholine for tracheal intubation. Patients were randomly assigned to one of three groups of 20 each (inspired 0.5% isoflurane, 1% isoflurane or 0.5% halothane), combined with 50% N2O and O2. After delivery, 67% N2O in O2 was used, supplemented by butorphanol. Maternal blood loss did not differ significantly among the three groups and none of the patients developed intraoperative awareness. At the time of delivery, maternal plasma epinephrine levels were significantly above preinduction levels in the 0.5% isoflurane group but unchanged in the other two groups. Neonatal status as ascertained by Apgar scores, cord acid base status and the Neurologic and Adaptive Capacity Scores (NACS) was equally good in the three groups of patients. Serum inorganic fluoride concentrations in the mother after anesthesia were not significantly above preanesthetic levels in any of the groups and there was no biochemical evidence of renal toxicity. In all neonates fluoride ion concentrations in the first voided urine sample were less than 7 μmol/l, a value well below that associated with nephrotoxicity. It is concluded that isoflurane is a safe supplement to N2O – O2 mixture for cesarean section and is a safer alternative to halothane in situations when patients receiving beta‐adrenergic therapy require cesarean section since halothane might potentiate arrhythmias caused by beta adrenergic agonists.
Neuromuscular blockade induced by flunarizine alone and in combination with pancuronium, suxamethonium or neomycin: studies in isolated rat phrenic‐hemidiaphragm preparations
Authors: Bozo E. del , Baeyens J. M.
Published: January 2009

Thein vitroeffects of flunarizine on indirectly‐ and directly‐elicited contractions in rat phrenic‐hemidiaphragm preparations were studied. The interactions of flunarizine with non‐depolarizing and depolarizing neuromuscular blocking drugs (pancuronium and suxamethonium) and with an aminoglycoside antibiotic (neomycin) were also evaluated. Flunarizine induced a slowly developing concentration‐dependent reduction of indirectly‐elicited diaphragm twitch height, but only slightly reduced directly‐elicited contractions. Flunarizine 1 and 5 μmol · 1‐1produced a concentration‐dependent enhancement of pancuronium‐induced neuromuscular blockade, whereas suxamethonium blockade was significantly increased by flunarizine 5 μmol · 1 ·‐1only. Moreover, both flunarizine 1 and 5 μmol · 1‐1also increased the neuromuscular blockade induced by neomycin. In conclusion, flunarizine induced neuromuscular blockade and enhanced the effects of several neuromuscular blocking agents to varying degreesin vitro.
Motor blockade and EMG recordings in epidural anaesthesia. A comparison between mepivacaine 2%, bupivacaine 0.5 % and etidocaine 1.5%
Authors: Nydahl P.‐A. , Axelsson K. , Philipson L. , Leissner P. , Larsson P. G.
Published: January 2009

In a double‐blind study young volunteers randomly received 20 ml of mepivacaine 2%, bupivacaine 0.5% or etidocaine 1.5% epidurally, all solutions with adrenaline. The mean cephalad spread of pin‐prick analgesia was equal (T10) in the groups, but the duration was longest for bupivacaine and etidocaine. The motor blockade of the rectus abdominis muscles was assessed quantitatively by rectified integrated electromyographic recordings (RIEMG) and as number of turns in EMG recordings [changes in the direction (rise/fall) of the EMG; TURNS] from three different segmental levels, T7, T9 and T11. The motor blockade of the quadriceps muscles was estimated by EMG recordings simultaneously with muscle force measurements at maximal isometric knee extension. Motor blockade was also evaluated by the Bromage scale. There was good correlation (correlation coefficient 0.91) between RIEMG values and muscle force in knee extension during epidural anaesthesia. TURNS showed a non‐linear relationship to isometric force during epidural anaesthesia and added no further information. At the lower parts of the abdomen (T11), etidocaine gave more profound and longer motor blockade than mepivacaine. For quadriceps muscle function, motor blockade was almost complete with all three local anaesthetics; the duration of maximum motor blockade was short (45–60 min) for mepivacaine, but about 5 h with etidocaine. At the time when the Bromage scale indicated complete regression of motor blockade, the muscle force of knee extension was only 30% and the quadriceps RIEMG 35% of control values and 1–3 h remained until the time of mobilization. The difference between the segmental level of maximal mean pin‐prick analgesia and that of motor blockade was roughly 4 segments with mepivacaine and bupivacaine and 2.5 segments with etidocaine. The time of complete regression of analgesia and the time of complete regression of motor blockade (knee extension) were about the same for mepivacaine (180 min) and bupivacaine (380 min). With etidocaine, quadriceps muscle force reverted at 580 min and motor blockade outlasted sensory block by 150 min.
Atelectasis and gas exchange impairment during enflurane/nitrous oxide anaesthesia
Authors: Gunnarsson L. , Strandberg A. , Brismar B. , Tokics L. , Lundquist H. , Hedenstierna G.
Published: January 2009

The development of atelectasis and effects on gas exchange during enflurane anaesthesia in nitrogen/oxygen or nitrous oxide/oxygen (inspired oxygen fraction 0.4) were studied in 16 lung‐healthy patients (mean age 49 years). Awake, no subject displayed atelectasis as assessed by computed x‐ray tomography of the thorax. Pulmonary gas exchange, studied by multiple inert gas elimination technique, and blood gases were normal. After 10 min of enflurane anaesthesia in nitrogen/oxygen, 14 of 16 subjects had developed atelectasis. After 30 min of enflurane anaesthesia in nitrogen/oxygen or nitrous oxide/oxygen, all patients had developed atelectasis, and a further increase was observed after 90 min of anaesthesia to approximately 5% of the intrathoracic area. There was no difference between the two anaesthesia groups. In the nitrogen group, shunt rose to a maximum of 5.8% at 30 min of enflurane anaesthesia, with a significant reduction to the initial anaesthesia level after 90 min of anaesthesia (3.4%). Perfusion of poorly ventilated lung regions (low VA/Q) averaged 4–5% and did not vary significantly during the anaesthesia. In the nitrous oxide group, shunt increased to 6.3% after 90 min of anaesthesia, and there was a parallel decrease in perfusion of low VA/Q regions. The findings suggest that besides prompt collapse of lung tissue during induction of anaesthesia, absorption of gas from closed‐off or poorly ventilated regions takes place and further increases the atelectatic area.
Hemodynamic effect of epidurally administered epinephrine in middle‐aged and elderly patients
Authors: Tomoda M. K. , Ueda W. , Hirakawa M.
Published: January 2009

The circulatory effects of epinephrine, added to local anesthetic, during epidural analgesia were compared between middle‐aged (52–65 years) and elderly (75–82 years) patients undergoing transurethral resection of the prostate. We used 10 ml of 1.5% lidocaine with or without 1:200 000 epinephrine. The plasma epinephrine concentration peaked 5–10 min after the injection in the patients who received epinephrine with anesthetic. There was no significant difference in the plasma epinephrine concentration between the two age groups. Epinephrine caused a significant increase in the heart rate and a significant reduction in the diastolic arterial pressure in both age groups. A significant reduction of the systolic arterial pressure, however, occurred only in the middle‐aged patients. Neither the plasma concentration of endogenous epinephrine, heart rate nor arterial pressure changed significantly in the patients who received plain lidocaine. We conclude that the increase in the heart rate and decrease in the diastolic arterial pressure induced by epinephrine when added to an analgesic may not be influenced by advancing age. In contrast, the reduction in the systolic arterial pressure caused by epinephrine may become less pronounced with age.
Spread of spinal anaesthesia using various doses of plain 0.5 % bupivacaine injected at the LIV—V interspace
Authors: Taivainen T. , Tuominen M. , Rosenberg P. H.
Published: January 2009

Spinal anaesthesia with 3 ml, 4 ml or 5 ml of plain 0.5%, bupivacaine was performed in three groups of 20 orthopaedic (ASA I) patients at the LIV‐V interspace. Patients aged less than 20 years or more than 60 years and those outside the normal range of body mass index were excluded. The spread of analgesia was greater in the 4‐ml and 5‐ml groups compared to the 3‐ml group at each testing time (P<0.05). The mean maximum cephalad spread of pinprick analgesia (± s.d.) 60 min after injection was significantly higher (P<0.05) in the 4‐ml group (T10 ± 3.2) and in the 5‐ml group (T10 ± 2.7) than in the 3‐ml group (T12 ± 2.1). The interindividual variability of the cephalad spread of analgesia was greater in the 4‐ml and 5‐ml groups compared to the 3‐ml group (P< 0.05). The degree of motor block was higher in the 5‐ml group than in the 3‐ and 4‐ml groups at 5 and 15 min after injection. In seven patients the first sign of motor block was the patient's inability to flex the ankle, rather than inability to raise an extended leg as was the case in the other patients. In all patients satisfactory anaesthesia for surgery of the lower extremity was achieved.
The influence of halothane and thiopental on respiratory‐related nerve activities in decerebrate cats
Authors: Masuda A. , Ito Y. , Haji A. , Takeda R.
Published: January 2009

The effects of halothane and thiopental on the respiratory efferent activities in the phrenic, recurrent laryngeal and hypoglossal nerves were studied in decerebrate, paralyzed and artificially ventilated cats. Inhalation of halothane (2%, 90 s) and intravenous injection of thiopental (2–3 mg/kg) produced a similar change in the breathing pattern, characterized by an increase in respiratory frequency and a decrease in the respiratory burst discharge in the three nerves studied. Depression of the respiratory activity was greatest in the hypoglossal nerve, intermediate in the recurrent laryngeal nerve, and least in the phrenic nerve. Both drugs diminished the whole power spectral densities of the three nerves. Thiopental selectively attenuated the high frequency peaks of these spectra and shifted the peak frequencies to lower values. Bilateral section of the vagus and carotid sinus nerves had no effect on the action of thiopental on the respiratory neural activities, whereas it decreased, but did not eliminate, the action of halothane. The present results demonstrate that both halothane and thiopental produce a selective depression of the upper airway motor activities, with stronger effects on the hypoglossal nerve. Effects on the peripheral receptors and the central respiratory drives differ between the two drugs.
Effects of epidural analgesia on plasma calcitonin gene‐related peptide
Authors: Bythell V. E. , Lacoumenta S. , Breimer L. H. , Brooks S. , Burrin J. M. , Hall G. M.
Published: January 2009

The effects of epidural analgesia on plasma calcitonin gene‐related peptide (CGRP) values during and after hysterectomy were investigated in 14 healthy patients. In seven patients who received general anaesthesia alone for pelvic surgery, there were no significant changes in plasma CGRP concentrations. In the remaining patients, who received extensive epidural blockade in addition to general anaesthesia, there were again no significant changes in plasma CGRP values. This was in spite of profound sympathetic blockade, as shown by marked hypotension and a significant decline in plasma catecholamines. The epidural group of patients showed the expected attenuation of the glucose, cortisol and growth hormone responses to surgery. The results show that circulating CGRP is unlikely to be involved in the modulation of peripheral vascular tone during pelvic surgery under either general or epidural anaesthesia.
The association between the neuroleptic malignant syndrome and malignant hyperthermia
Authors: Adnet P. J. , Krivosic‐Horber R. M. , Adamantidis M. M. , Haudecoeur G. , Adnet‐Bonte C. A. , Saulnier F. , Dupuis B. A.
Published: January 2009

The neuroleptic malignant syndrome (NMS) is an uncommon but dangerous complication of treatment with neuroleptic drugs. A primary defect in skeletal muscle has been suggested in view of similarities in the clinical presentations of NMS and anaesthetic‐induced malignant hyperthermia (MH). The in vitro halothanecaffeine contracture tests are the most reliable method of identifying individuals susceptible to MH. The aim of this study was to define if a relationship exists between NMS and MH susceptibility. Hence, the in vitro halothane and caffeine contracture tests were performed on muscle tissue obtained from eight NMS, ten MH‐susceptible and ten control patients. The results, which are expressed in accordance with the criteria of the European MH Group, defined the eight NMS subjects as MH non‐susceptible. The response to halothane and caffeine exposure of skeletal muscle from NMS and control subjects was the same and significantly different from that of muscle from patients susceptible to MH. Furthermore, muscle from subjects in NMS and control group responded similarly to increasing concentrations of chlorpromazine. These results do not point towards an association between NMS and MH.
Reversal of postoperative somnolence using a two‐rate infusion of physostigmine
Authors: Hartvig P. , Lindström B. , Pettersson E. , Wiklund L.
Published: January 2009

In order to antagonize immediate postoperative somnolence, 24 surgical patients were given a two‐rate infusion of physostigmine, aiming at a constant plasma concentration in the range of 1 to 10 ng/ml. Plasma concentrations of physostigmine were determined during infusion and after infusion and the effects of physostigmine on analgesia and postoperative sedation, and its side effects were monitored throughout. On the 1st postoperative day some of the patients (n=8) were given 5 mg physostigmine orally, after which plasma concentrations as well as effects were measured. Steady‐state concentrations were generally lower than predicted. Clearance varied between 10 and 85 ml/min × kg with a mean of 40.8 ± 21.0 ml/min × kg. Oral bioavailability was 25.3 ± 11.1%. Physostigmine administered as an intravenous infusion antagonized immediate postoperative somnolence in 21 out of 24 patients. Effects were poorly correlated with the established steady‐state concentration of physostigmine. The patients' experience of postoperative pain relief was mostly satisfactory and the side effects of physostigmine infusion were generally limited. The effects of physostigmine in the immediate postoperative period seemed dependent on the dose as well as on the time which had elapsed since administration of anticholinergic drugs. After oral physostigmine administration the following morning, the majority of patients experienced side effects such as nausea and abdominal pain. In conclusion, physostigmine given as infusion antagonizes postoperative somnolence. However, the arousal effect was considered not better than that resulting from a bolus dose of the drug, although the infusion regimen allowed a prolonged clinical effect duration.
Cyanide release from sodium nitroprusside during coronary bypass in hypothermia
Authors: Undquist P. L. , Rosling H. , Tydén H.
Published: January 2009

Erythrocyte cyanide levels were determined by a sensitive fluorimetric method on four occasions during coronary bypass in hypothermia in 18 consecutive patients treated with sodium nitroprusside (SNP) with an infusion rate less than 1 μg × kg‐1 × min‐1. Every second patient received the cyanide antidote thiosulphate simultaneously with the SNP‐infusion. At normal body temperature, as well as during hypothermia in cases receiving thiosulphate, the cyanide levels rose slowly but significantly with the infusion rate. Higher erythrocyte cyanide levels in relation to the infusion rates, up to 8.0 μmol/1, were found during hypothermia in two of the cases not receiving thiosulphate. We conclude that SNP is broken down to cyanide even under hypothermia and that low body temperature may impair the conversion of cyanide to thiocyanate, probably by affecting the metabolic pathways providing the sulphur substrate. This effect may add to other factors decreasing sulphur availability in critically ill patients, and simultaneous administration of thiosulphate is therefore recommended to ensure a safe SNP treatment during and after coronary bypass operations.