bluuebunny/crossref_metadata_2025_split huggingface dataset:
Epidural fentanyl markedly improves thoracic epidural analgesia in a low‐dose infusion of bupivacaine, adrenaline and fentanyl
Authors: Niemi G. , Breivik H. 
Published: March 2003

Background: The objectives of the present study were to evaluate the effects on postoperative pain intensity, pain relief, and side effects when removing fentanyl from an optimally titrated epidural infusion consisting of bupivacaine, fentanyl and adrenaline.Methods: A prospective, randomized, double‐blind, crossover study was carried out in 20 patients after major upper abdominal surgery requiring a large longitudinal incision. Patients with only mild pain when coughing during thoracic epidural infusion of about 10 ml per hour of bupivacaine 1 mg · ml−1, fentanyl 2 μg · ml−1, and adrenaline 2 μg · ml−1 were included. On the 1st and 2nd postoperative days, each patient was given a double‐blind epidural infusion, at the same rate, with or without fentanyl. The effects were observed for 6 h or until pain when coughing became unacceptable in spite of rescue analgesia. Rescue analgesia consisted of up to two patient‐controlled epidural bolus injections (4 ml) per hour and intravenous morphine if necessary.Results: Main outcome measures, i.e. pain intensity when coughing and at rest, increased (P<0.001) when fentanyl (19.2±5.2 μg · h−1) was omitted from the epidural infusion: after 6 h pain intensity when coughing had increased to unacceptable levels in spite of increased consumption of rescue bupivacaine and adrenaline (P<0.001). Within 15–20 min after restarting the triple epidural mixture with fentanyl, pain intensity was again reduced to mild pain when coughing.Conclusions: A low dose of epidural fentanyl (20 μg · h−1) markedly improved the pain‐relieving effect of bupivacaine and adrenaline infused epidurally at a thoracic level after major upper abdominal surgery. This dose of fentanyl is much too small to relieve severe dynamic pain when given systemically. Therefore, this study indirectly supports the view that a low‐dose thoracic epidural infusion of fentanyl has a spinal analgesic site of action.
Lung recruitment at birth does not improve lung function in immature lambs receiving surfactant
Authors: Björklund L. J. , Ingimarsson J. , Curstedt T. , Larsson A. , Robertson B. , Werner O. 
Published: March 2003

Background: In mature animals with surfactant deficiency induced by lung lavage, the therapeutic effect of exogenous surfactant is enhanced by a lung recruitment maneuver. We then tested whether a lung recruitment maneuver at birth immediately before surfactant treatment would improve lung function also in preterm lambs with surfactant deficiency due to immaturity.Methods: Ten newborn lambs with a gestational age of 127 days were randomized to receive surfactant either before the first breath or immediately after a lung recruitment maneuver consisting of five sustained inflations of 8, 16 or 32 ml/kg. Functional residual capacity was measured by sulfur hexafluoride washout, and inspiratory capacity as well as maximal compliance were obtained from a static expiratory pressure–volume curve after the lungs had been inflated to 35 cm H2O. In addition, blood gases were obtained. Measurements were made at 15, 45, 175, 135, 170 and 230 min after birth. Post mortem histological examinations of the lungs were performed in a blinded fashion.Results: The lung recruitment maneuvers did not improve oxygenation. Inspiratory capacity, static compliance and functional residual capacity at 4 h, as well as post mortem intrapulmonary air volume, had an inverse relation to the size of inflations given at birth. There was also a negative correlation between size of inflations at birth and response to surfactant therapy, as assessed by lung microscopy.Conclusion: Lung recruitment at birth does not improve the response to surfactant in immature lambs, but may instead have an adverse effect on lung function and morphology.
Dose–response relationship of propofol on mid‐latency auditory evoked potentials (MLAEP) in cardiac surgery
Authors: Palm S. , Linstedt U. , Petry A. , Wulf H. 
Published: March 2003

Background: Propofol‐sufentanil anaesthesia has become popular during cardiac surgery for its titrability and short recovery time. Avoidance of awareness is a major goal during cardiac surgery. We therefore investigated the dose–response relationship of propofol and cortical responses (mid‐latency auditory evoked potentials, MLAEP).Methods: One hundred patients undergoing cardiac surgery were investigated. Basic anaesthesia was performed with sufentanil (4.5 μg kg−1 h−1) / flunitrazepam (9 μg kg−1 h−1) infusion (control group); the other groups received in addition a loading dose of propofol 2 mg kg−1 and a maintainance infusion of 1–3.5 mg kg−1 h−1. MLAEP were evaluated by using Pa/Nb‐amplitudes and Nb‐latencies. Haemodynamics were monitored by ECG, arterial blood pressure and cardiac function with pulmonary artery catheterization.Results: In the control group, median amplitude of MLAEP decreased by 50% with a wide range, but were detectable in >90% of patients throughout surgery. Propofol suppressed amplitude Pa/Nb of MLAEP dose dependently. With 3.5 mg kg−1 h−1 amplitudes disappeared in >40% of patients throughout cardiac surgery. Median Nb‐latencies increased in the control group from 44 to a range from 50 to 60 ms. In groups with propofol >2 mg kg−1 h−1, Nb‐latencies, detectable in the patients without complete suppression of MLAEP, increased to median 60 ms. Haemodynamic parameters and cardiac function did not differ among the groups. The use of vasopressors was not increased even with the highest propofol dose used.Conclusion: The dose–response effect of propofol on auditory evoked potentials reveals that combining a loading dose of 2 mg kg−1 with a consecutive infusion of 3.5 mg kg−1 h−1 significantly suppresses MLAEP during cardiac surgery. Thus, auditory information may not be processed and awareness with recall becomes unlikely.
Preoperative blood pressure and intraoperative hypothermia during lower abdominal surgery
Authors: Kasai T. , Hirose M. , Matsukawa T. , Takamata A. , Kimura M. , Tanaka Y. 
Published: March 2003

Background: Preoperative factors including age and body habitus affect intraoperative hypothermia during general anesthesia. We hypothesized that preoperative blood pressure also plays a contributory role in the induction of intraoperative hypothermia.Methods: We evaluated the effect of preoperative systolic blood pressure (SBP) on core temperature during lower abdominal surgery under general anesthesia. In 36 female patients under 65 years of age, patients with a preoperative SBP of 140 mmHg or greater upon arrival in the operating theater were assigned to the high SBP group (n=18), while those with SBP below 140 mmHg were assigned to the normal SBP group (n=18). Anesthesia was maintained with isoflurane and nitrous oxide combined with epidural buprenorphine, and routine thermal care was provided intraoperatively.Results: There were no significant differences in age, height or weight between the two groups. Tympanic membrane temperature in the normal SBP group started to decrease significantly from 15 min after induction of anesthesia compared to that in the high SBP group, and continued to decrease further at two hours after induction. Vasoconstriction threshold, determined to be tympanic membrane temperature at the time when a forearm minus finger skin surface gradient exceeded 0 °C, was significantly higher in the high SBP group than in the normal SBP group.Conclusion: These results suggest that preoperative SBP has some preventive effect on the decrease in intraoperative core temperature during lower abdominal surgery under general anesthesia.
How do anaesthesiologists treat malignant hyperthermia in a full‐scale anaesthesia simulator?
Authors: Gardi T. i , Christensen U. C. , Jacobsen J. , Jensen P. F. , Ørding H. 
Published: March 2003

Background: Clinical malignant hyperthermia (MH) is rare and usually occurs unexpectedly. Prompt diagnosis and correct treatment is crucial for survival of the patient developing fulminant MH. The aims of the present study were to investigate whether anaesthesiologists could make a correct diagnosis of MH and to evaluate their treatment of fulminant MH in a simulator.Methods: Thirty‐two teams (one anaesthesiologist/one nurse anaesthetist) were exposed to an event of clinical MH in a full‐scale simulator. Their performance was videotaped for retrospective analysis of the treatment on the basis of the recommendations of the Danish Malignant Hyperthermia Register.Results: All 32 teams asked the surgeon to terminate the surgery as fast as possible, switched off the vaporiser and administered 100% oxygen. Although all intended to hyperventilate the patient, only 14 teams actually managed to perform the hyperventilation. Most problems were found in teams that switched to manual ventilation. All teams treated the patient with dantrolene, and symptomatic treatment was initiated by all even though some elements of the full treatment were lacking, possibly due to the limited time available.Conclusion: All teams diagnosed MH in the simulator satisfactorily. The surprising negative finding was that more than half of the participants failed to hyperventilate the “patient” although they intended to do so. This investigation shows that the problem in these teams’ treatment of MH was more a question of practical management of the resources than lack of theoretical knowledge.
Probability of acceptable intubation conditions with low dose rocuronium during light sevoflurane anaesthesia in children
Authors: Eikermann M. , Renzing‐Köhler K. , Peters J. 
Published: March 2003

Background: To define the rocuronium doses which would provide 50%, 90%, and 95% probability of ‘acceptable’ intubation conditions during light sevoflurane anaesthesia, we studied 60 children aged 2–7 years in a prospective, randomised, assessor blinded study.Methods: After mask ventilation with 1 MAC sevoflurane/N2O for 17±1 (x&#x030c;±SD) min we administered rocuronium (either 0.15, 0.22, 0.3, 0.5, or 1.0 mg  ·  kg−1) or placebo, and quantified the evoked force of the adductor pollicis muscle. Intubation conditions were assessed before and 2 min after injection of the test drug.Results: Intubation conditions were improved significantly with rocuronium and scored ‘acceptable’ in 70%, 90%, and 100% of the children after injection of rocuronium 0.15, 0.22, and 0.3 mg  ·  kg−1, respectively. In parallel, twitch tension decreased to 53% (6–100), 26% (11–100), and 11% (0–19) of baseline (median (range)). Recovery of train‐of‐four ratio to 0.8 was achieved 13 (7–19), 16 (8–28), and 27 (23–44) min after injection of the respective rocuronium doses. Higher rocuronium doses did not further improve intubation conditions but only prolonged time of neuromuscular recovery. Logistic regression analysis revealed that rocuronium 0.11 (CI 0.05–0.16), 0.21 (0.14–0.28), and 0.25 (0.15–0.34) mg  ·  kg−1 provides a 50%, 90%, and 95% probability of ‘acceptable’ intubation conditions in children during 1 MAC sevoflurane/N2O anaesthesia, respectively. Furthermore, we calculated that force depression of adductor pollicis muscle to 81% (CI 72–90), 58% (42–74), and 50% (29–71) of baseline is associated with 50%, 90%, and 95% probability of ‘acceptable’ intubation conditions.Conclusions: Submaximal depression of muscle force with low dose rocuronium improves intubation conditions in children during light sevoflurane anaesthesia while allowing rapid recovery of neuromuscular function. However, when using low dose rocuronium neuromuscular monitoring may be helpful to detect children with inadequate response to the relaxant so as to avoid an unsuccessful intubation attempt.
Effect of expiratory resistance on gas‐exchange and breathing pattern in chronic obstructive pulmonary disease (COPD) patients being weaned from the ventilator
Authors: Lourens M. S. , Berg B. Van Den , Hoogsteden H. C. , Bogaard J. M. 
Published: March 2003

Background: The majority of patients with severe chronic obstructive pulmonary disease (COPD) have flow limitation, which has deleterious side effects. If these patients are mechanically ventilated, this often results in difficult weaning. Spontaneously breathing COPD patients experience a beneficial effect of pursed lip breathing. We investigated whether in intubated COPD patients application of an external resistance could produce the same beneficial effects on breathing pattern and gas‐exchange as pursed lip breathing.Methods: Ten COPD patients with flow limitation were studied during pressure support mechanical ventilation. Two types of expiratory resistances were applied: one fixed level of resistance and one with a resistive pressure decay. Each resistance was applied in 5 patients and the highest level was chosen that did not cause hyperinflation. Blood gas values and breathing pattern with and without resistance were compared.Results: With resistance 1, gas‐exchange and breathing pattern did not change significantly; average PCO2 changed from 8.0 to 8.1 kPa, PO2 from 10.2 to 10.3 kPa, tidal volume from 0.380 to 0.420 l, respiratory rate from 25 to 23 bpm and inspiratory:expiratory ratio from 1:1.9 to 1:2.0. With resistance 2, gas‐exchange and breathing pattern did not change significantly; average PCO2 changed from 5.8 to 6.0 kPa, PO2 from 11.1 to 12.1 kPa, tidal volume from 0.733 to 0.695 l, respiratory rate from 16 to 18 bpm and inspiratory:expiratory ratio from 1:2.3 to 1:2.9.Conclusion: In intubated COPD patients being weaned from the ventilator, application of an external resistance did not have the same beneficial effects as pursed lip breathing.
Hemodynamic and sympathetic effects of fenoldopam and sodium nitroprusside
Authors: Yakazu Y. , Iwasawa K. , Narita H. , Kindscher J. D. , Benson K. T. , Goto H. 
Published: March 2003

Background: Fenoldopam is a novel dopamine‐1 receptor selective agonist that can be used as a vasodilator perioperatively to treat hypertension and to produce induced hypotension. We were interested to find out whether there were any differences between fenoldopam (FM) and sodium nitroprusside (SNP), one of the most popular vasodilators, in their effects on hemodynamics and sympathetic outflow using not only neuraxis intact but also baro‐denervated animal models.Methods: A total of 60 New Zealand white rabbits were divided into two groups of 30 each: the neuraxis‐intact group and the totally baro‐denervated group. Each group was further divided into three groups of 10 each to receive SNP 10 μg · kg−1, FM 10 μg · kg−1 or FM 20 μg · kg−1, respectively. Mean arterial pressure (MAP), heart rate (HR) and renal sympathetic nerve activity (RSNA) were recorded before and after intravenous (i.v.) administration of each agent. In addition, cardiac and sympathetic baroreflex sensitivity were assessed in the neuraxis‐intact animals.Results: In the neuraxis‐intact groups, although RSNA was increased to a similar extent in all three groups (P<0.01), the reduction of MAP with FM groups was significantly greater than with SNP (P<0.05). HR was increased only in the SNP group. Cardiac (HR) and sympathetic barosensitivity were significantly attenuated with FM 20 μg · kg−1 as compared to the SNP group. In the baro‐denervated groups, there were significant and similar degrees of reduction of MAP in all three group up to 1 min (P<0.01). MAP remained significantly decreased in the FM groups for 10 min (only 2 min with SNP) in both animal models.Conclusions: Unlike sodium nitroprusside, fenoldopam attenuates both cardiac (heart rate) and sympathetic baroreflex sensitivity, which may explain the lack of rebound hypertension with fenoldopam. The offset of hypotensive effects of fenoldopam is a significantly slower process as compared to nitroprusside, and this may be an unfavorable feature of fenoldopam should overshoot of hypotension occur.
Danish Anaesthesia Allergy Centre – preliminary results
Authors: Garvey L. H. , Roed‐Petersen J. , Menné T. , Husum B. 
Published: March 2003

Background: Anaphylactoid reactions in anaesthesia are rare and should ideally be investigated in specialist centres. At Gentofte University Hospital, we established such a centre in 1998 as a joint venture between the Departments of Anaesthesiology and Dermatology. We present the methodology, diagnostic algorithm and preliminary results from our centre.Methods: We are open for referral of patients from all of Denmark. Reactions are classified using a three‐grade severity scale and all reactions ranging from mild to severe are investigated. Investigations follow a standard step‐by‐step protocol of in vitro testing and skin testing. Blood samples for tryptase analysis are taken at the time of reaction and a control sample is taken together with samples for specific IgE analysis 2–4 weeks after the reaction. Subsequent skin testing comprises both prick tests and intradermal tests in most cases. Patients are tested with all substances they were exposed to, including antibiotics, colloids, latex and chlorhexidine.Results: A total of 68 patients have been referred to date (July 2001) and 36 have completed investigations. Positive test results were mainly seen in patients with more severe reactions, and there were more men than women in the group with the most severe reactions. Six patients had positive specific IgE, three for penicillin, two for latex and one for thiopental. In all, 21 patients had positive skin tests to various substances, of whom four men with anaphylactic shock tested positive for chlorhexidine. Only one patient has tested positive to a neuromuscular blocking drug (NMBD) so far.Discussion:Our preliminary results appear to differ in two ways from results usually found in this field. Firstly, only one patient has tested positive for a NMBD and secondly, we have had four patients with anaphylactic shock who have tested positive for chlorhexidine. Possible reasons for these differences are discussed.
Practice and knowledge of cricoid pressure in southern Sweden
Authors: Schmidt A. , Åkeson J. 
Published: March 2003

Background: For 40 years cricoid pressure has been used to prevent regurgitation of gastric contents during induction of anaesthesia. Recent studies have emphasised use of more moderate force so as not to deteriorate ventilation or endotracheal intubation. This study was undertaken to assess the current practice and knowledge of cricoid pressure among anaesthesia personnel in southern Sweden.Methods: Forty‐eight subjects at two anaesthetic departments in southern Sweden were asked to apply and maintain cricoid pressure for 60 s with their dominant and non‐dominant hands, respectively, in a laryngotracheal model during simulated intravenous induction of anaesthesia. Where and how pressure was applied as well as the force used by each subject was recorded together with information on individual experience and knowledge of the technique.Results: There were no significant changes in force applied over time, and no significant differences in force between dominant (median 36 N; 25th percentile 26 N; 75th percentile 50 N) and non‐dominant (37; 26; 50 N) hand, between female and male subjects or between physicians, nurses and assistant nurses. Force exceeding 60 N was recorded at least once in 21% of subjects. More than two‐thirds (69%) had not heard of any recommended level of force to be applied. Forty percent of anaesthesiologists were unaware of any contraindications.Conclusion: More specific education and training seems mandatory to improve clinical use of cricoid pressure and possibly increase patient safety. Simulators allowing cricoid pressure to be carried out and evaluated in a standardised manner should therefore be incorporated into future training programmes and airway management courses.
Reorganization of actin in neurons after propofol exposure
Authors: Oscarsson A. , Massoumi R. , Sjölander A. , Eintrei C. 
Published: March 2003

Background: It has previously been shown that propofol in clinically relevant concentrations induces a calcium‐dependent conformational change in the cytoskeleton. The aim of this study was to further clarify the effect of propofol on the actin cytoskeleton and to determine if this conformational change is mediated by the interaction between the GABAA‐receptor and propofol.Methods: Primary cultured cortical neurons from newborn rats were treated with propofol 3 μg · ml−1 in a time‐response titration, with and without preincubation with the GABAA‐receptor antagonist, bicuculline. Actin‐protein content was detected by Western blot analysis and the cellular content of F‐actin measured by a spectrophotometric technique.Results: Propofol triggers a relatively slow statistically significant increase in the intracellular F‐actin content, maximum after 20‐min incubation (160%±16.3) (mean±SEM) P<0.05. The propofol‐induced increase in F‐actin was effectively blocked by bicuculline. The increase in intracellular actin content after exposure to propofol as well as the effect of bicuculline were verified by Western blot analysis.Conclusion: The present study shows that propofol triggers a time‐dependent change of actin. Since this reorganization can be blocked effectively by a GABAA‐receptor antagonist, this suggests that the GABAA‐receptor is involved in the pathway leading to cytoskeletal reorganization after propofol treatment. The actin polymerization reached its maximum after 20 min. Therefore, we believe that the propofol‐induced changes might be connected with slower cellular responses such as cell‐to‐cell interaction and/or channel regulation.
The effects of propofol or halothane on free radical production after tourniquet induced ischaemia‐reperfusion injury during knee arthroplasty
Authors: Aldemir O. , Celebi H. , Cevik C. , Duzgun E. 
Published: March 2003

Background: Ischaemia‐reperfusion injury following tourniquet release is a good in vivo model for evaluating acute conditions. The aim of the study was to investigate the effects of propofol or halothane anaesthesia on oxidative stress by determining malondialdehyde (MDA) levels during knee arthroplasty.Methods: Thirty patients undergoing orthopaedic surgery were divided into two groups. Anaesthesia was induced with either fentanyl 100 μg and propofol 2 mg kg−1 (Group 1) or fentanyl 100 μg and thiopentone 5 mg kg−1 (Group 2) and maintained with infusion of propofol in Group 1 or inhalation of halothane in Group 2. ECG, SpO2, EtCO2, and mean arterial pressure (MAP) were monitored. Venous and arterial blood samples were obtained at different measurement times for MDA and blood gas analyses.Results: There was a significant decrease in MAP in the 1st and 5th minutes after tourniquet release (ATR) when compared with the 5th minute before tourniquet release (BTR) in both groups. Heart rate (HR) increased significantly in the 1st minute ATR in Group 1 only. EtCO2 increased significantly in the 1st and 5th minutes ATR, SpO2 decreased in the 1st minute ATR in both groups. There was a significant decrease in pH and increase in pCO2 at 1, 5 and 30 min ATR in both groups. pO2 values decreased in the 1st minute ATR in Group 1 only and returned to control values at 5 min ATR and decreased at 30 min ATR in the recovery room in both groups. The differences in SaO2 were similar to SpO2. MDA levels decreased before and after release of tourniquet when compared to baseline in both groups. However, there was a statistically significant decrease only in Group 1.Conclusion: Propofol may be a good choice of anaesthetic when an ischaemia‐reperfusion injury is anticipated as in orthopaedic surgery requiring a tourniquet, due to its antioxidant properties, but halothane needs further study.