bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of sevoflurane on the mid‐latency auditory evoked potentials measured by a new fast extracting monitor
Authors: Alpiger S. , Helbo‐Hansen H. S. , Jensen E. W. 
Published: March 2003

Background: Mid‐latency auditory evoked potentials (MLAEP) are widely suppressed during general anesthesia and may therefore be useful for assessment of the depth of anesthesia. However, interpretation of amplitudes and latencies in the AEP signal is time consuming. A new monitor (A‐line™) that quantifies the MLAEP into an index has therefore been developed. The present study aimed to assess the precision of a prototype of the new monitor and to test the hypothesis that the depth of anesthesia index shows a graded response with changing steady‐state end‐expiratory concentrations of sevoflurane.Methods: We studied 10 ASA physical status I or II patients undergoing elective hysterectomy under combined epidural and general anesthesia by sevoflurane. Baseline auditory evoked potentials were recorded in the conscious patient immediately before induction of general anesthesia. Depth of anesthesia indices were recorded before anesthesia and at decreasing end‐expiratory steady‐state sevoflurane concentrations of 2.0%, 1.5%, 1.0% and 0.5%. All indices were recorded in duplicate 6 s apart. By use of an autoregressive model with exogenous input (ARX‐model), the monitor extracted the AEP within 6 s. The depth of anesthesia AEP index calculated in this way was defined as the A‐line ARX index (AAI).Results: Approximately 95% of the differences between repeated recordings were 5 AAI‐units or less. A wide interindividual variation was observed at each observation point. AAI at 1%, 1.5% and 2% end‐expiratory concentration was significantly less than the baseline AAI obtained before induction of anesthesia (P < 0.001). AAI did not change significantly in the 1–2% concentration range.Conclusion: The new monitor was precise. Attenuation of the A‐line ARX‐index (AAI) for mid‐latency auditory evoked potentials (MLAEP) during general anesthesia was profound. However, the monitor did not show a graded response with changing end‐expiratory steady‐state concentrations of sevoflurane.
Treatment of intracranial hypertension and aspects on lumbar dural puncture in severe bacterial meningitis
Authors: Grände P‐O. , Myhre E. B. , Nordström C‐H. , Schliamser S. 
Published: March 2003

Background: Brain stem herniation due to raised intracranial pressure (ICP) is a common cause of mortality in severe bacterial meningitis, but continuous measurements of ICP and the effects of ICP‐reducing therapy in these patients have, to our knowledge, not been described.Methods: During a four‐year period, an ICP‐monitoring device was implanted in patients admitted to our hospital with severe bacterial meningitis and suspected intracranial hypertension. ICP above 20 mmHg was treated using the Lund Concept, which includes antihypertensive therapy (β1‐antagonist,α2‐agonist), normalization of the plasma colloid osmotic pressure and the blood volume, and antistress therapy.Results: ICP above 20 mmHg was found in all 12 patients studied. It was effectively reduced in all but two patients, who died. Both patients had a low cerebral perfusion pressure (<10 mmHg), dilated pupils at start of therapy and were beyond recovery. Radiological signs of brain swelling were present in only five patients. Seven patients recovered fully, while mild audiological impairment was observed in two and minor neurological sequelae in one patient. Eight patients showed signs suggesting imminent brain stem herniation before start of ICP‐reducing treatment, seven of whom had been subjected to diagnostic lumbar dural puncture shortly before development of the brain stem symptoms. These symptoms gradually regressed after initiation of therapy, and in one patient reversal of brain stem herniation was documented by MRI.Conclusions: Severe bacterial meningitis can be associated with increased ICP, which can be reduced using the Lund Concept. The high survival rate, the low frequency of sequelae and the reversal of signs of imminent brain stem herniation in these high‐risk patients indicated beneficial effects of the intervention. The study confirms earlier observations that lumbar dural puncture is potentially hazardous in patients with intracranial hypertension, because it may trigger brain stem herniation. A normal CT brain scan does not rule out intracranial hypertension.
Intraoperative awareness: detected by the structured Brice interview?
Authors: Enlund M. , Hassan H. G. 
Published: March 2003

Background:  Awareness is a rare complication in general anesthesia, but its consequences are stressful. Efforts must be undertaken to prevent, diagnose, and, if occurring, treat it. The incidence of awareness is higher following anesthesia involving the use of muscle relaxants. As a part of a quality assurance program at our short‐stay surgery all patients exposed to general anesthesia are routinely subjected to a Brice interview, which aims to evaluate our standard anesthetic technique regarding awareness.Methods:  The Brice interview was used prospectively in 5216 patients given a propofol/opioid anesthetic for day‐case or short‐stay surgery. Neuromuscular blocks were used only for surgical needs, not routinely. All patients were interviewed on discharge from the recovery room. A second interview, according to Brice, was undertaken by telephone 3–7 days later in the case of a notable intraoperative event, or otherwise after postoperative patient complaints. All patients were also interviewed by telephone 1–2 days postoperatively.Results:  None of the patient interviews indicated awareness. This was also the case in five non‐relaxed patients who had an incident of light anesthesia with eye opening and gross motor response without forewarning. Neuromuscular blockade was used in 7% of patients.Discussion:  We were unable to detect intraoperative awareness. The anesthetic regimen, including minimal use of muscle relaxants, might be beneficial for awareness prevention. Alternatively, the diagnostic power, the timing of the Brice interview, or the number of interviews performed may be questioned.
Remifentanil infusion for cardiac catheterization in children with congenital heart disease
Authors: Foubert L. , Reyntjens K. , De Wolf D. , Suys B. , Moerman A. , Mortier E. 
Published: March 2003

Background:  Cardiac catheterization of children with congenital heart disease is increasingly being performed under general anesthesia. Haemodynamic stability during anesthesia and fast and adequate recovery after the procedure is crucial in these patients. We performed a pilot study to evaluate hemodynamic stability when using remifentanil for anesthesia during cardiac catheterization. We also evaluated extubation times and recovery characteristics.Methods:  In a randomized, prospective, double‐blind study 30 children (aged 1.5–20 months) received a continuous infusion of either 0.2 (group 0.2) or 0.3 µg/kg/min remifentanil (group 0.3) as part of a balanced anesthesia with 0.6 MAC sevoflurane. Heart rate, noninvasive arterial blood pressure, end tidal CO2 and pulse oxymetry were monitored throughout the procedure. Extubation times were noted, and recovery from anesthesia was evaluated using Aldrete scores.Results:  Haemodynamic response to intubation was well blunted in both groups. No significant changes in hemodynamic variables were noted from induction of anesthesia until 10 min after intubation. From then on there was a decrease in HR and systolic arterial pressure, which remained significant throughout the procedure in both groups. Extubation times were similar in both groups: 7.3 min (2,1) in group 0.2 vs. 6.6 min (2,1) in group 0.3 (NS). The number of patients with an Aldrete score of nine or more was 14 (group 0.2) vs. 15 (group 0.3), 10 min after extubation (NS).Conclusion:  Both dose regimens of remifentanil provided stable hemodynamic conditions during anesthesia for cardiac catheterization of children with congenital heart disease and allowed for rapid and adequate recovery.
Double‐blind comparison of the variability in spontaneous recovery of cisatracurium‐ and vecuronium‐induced neuromuscular block in adult and elderly patients
Authors: Pühringer F. K. , Heier T. , Dodgson M. , Erkola O. , Goonetilleke P. , Hofmockel R. , Gaetke M. R. , Mortensen C. R. , Upadhyaya B. , Eriksson L. I. 
Published: March 2003

Background:  This study was designed to compare variability in the offset of two neuromuscular blocking agents with different elimination pathways. Methods: The spontaneous recovery profiles of cisatracurium and vecuronium were compared in adult (18–64 years) and elderly (≥65 years) patients receiving N2O/O2/fentanyl/propofol anaesthesia. Patients were randomised to receive an initial bolus dose and maintenance doses of 3xED95, respectively, 0.6xED95 for cisatracurium (0.15 and 0.03 mg.kg−1) or 2xED95, respectively, and 0.4xED95 for vecuronium (0.1 and 0.02 mg.kg−1), as recommended in their prescribing information. Administration of the study drugs was double‐blinded, and neuromuscular transmission was monitored using mechanomyography of the evoked response of the adductor pollicis, following ulnar nerve stimulation. Results: The clinically effective duration (minutes) of the initial bolus dose, defined as the mean time to 25% T1 recovery (±SD), for the adult and elderly patients was 53.5±9.8 and 57.3±11.5 for cisatracurium, respectively, and 34.1±9.0 and 47.5±14.4 for vecuronium, respectively. The duration of spontaneous sufficient recovery (SSR), defined as the mean (±SD) time interval in minutes from 25% T1 recovery to a T4:T1 ratio ≧0.8 after the last bolus dose, for the adult, respectively, elderly patients was 28.3±8.0 and 31.7±10.0 for cisatracurium and 38.5±13.2 and 60.3±26.1 for vecuronium. Conclusion: Whereas both the clinically effective duration and the duration of SSR are comparable between the adult and the elderly patients receiving cisatracurium, they differ substantially between these two age groups for vecuronium. Furthermore, the variability in offset is significantly lower in patients receiving cisatracurium, especially in the elderly, which may be of particular clinical interest.
Oral clonidine premedication reduces the EC50 of propofol concentration for laryngeal mask airway insertion in male patients
Authors: Higuchi H. , Adachi Y. , Arimura S. , Nitahara K. , Satoh T. 
Published: March 2003

Background:  Oral clonidine, an α2‐adrenergic receptor agonist, reduces the dose of propofol required for laryngeal mask airway (LMA) insertion. Target‐controlled infusion (TCI) is becoming increasingly popular for propofol infusion. There is no information, however, on the propofol blood concentrations required for LMA insertion and the effect of oral clonidine premedication on these values. Methods: Propofol at target effect‐site concentrations from 4.0 to 12.0 µg/ml were randomly administered using TCI in three groups of healthy male patients (n=35 each) who were undergoing elective orthopedic surgery: control, 2.5 µg/kg clonidine, and 5.0 µg/kg clonidine groups. Nothing was administered to the control group. Clonidine(2.5 µg/kg or 5.0 µg/kg) was administered orally 90 min before arrival at the operating room in the clonidine groups. After equilibration between the blood‐ and effect‐site for 15 min, insertion of the LMA was attempted. The EC50 for LMA insertion (measured propofol serum concentration in equilibrium with the effect‐site at which 50% of patients do not respond to the insertion of the LMA) was determined by logistical regression. Results: EC50±standard error values in the control, 2.5 µg/kg clonidine, and 5.0 µg/kg clonidine groups were 8.72±0.55, 7.76±0.60, and 5.84±0.58 µg/ml, respectively. The EC50 in the 5.0 µg/kg clonidine group was significantly lower than that in the control group (P < 0.01). Conclusions: The propofol concentration required for LMA insertion in healthy male patients is reduced by premedication with 5.0 µg/kg oral clonidine.
Influence of surgery and endotoxin‐induced sepsis combined on natural killer cell activity, oxidative burst of granulocytes and antigen presentation capability of monocytes
Authors: Toft P. ,   Dagnæs‐Hansen, Tønnesen E. , Petersen M. S. 
Published: March 2003

Background:  Cell mediated immunity is affected in the course of sepsis and following surgical stress. The natural killer (NK) cells, the granulocytes and the monocytes constitute the immediate unspecific cell mediated immunity. We therefore investigated the effect of surgery‐ and endotoxin‐induced sepsis on NK cells, granulocytes and monocytes in a two‐hit model.Methods:  Three groups of 40 mice. Each group was divided into four groups of 10 mice. All the animals were anesthetized and subjected to either: laparotomy; treatment with Escherichia coli endotoxin i.p.; laparotomy followed 20 min later by endotoxin i.p.; or left untreated as a control group. In the first 40 mice the NK cell activity in the spleen and number of NK cells in the liver were measured, in the second the oxidative burst of granulocytes, and in the third the antigen presentation capacity of monocytes.Results:  Endotoxin stimulated the NK cell activity and up‐regulated the antigen presentation capability on monocytes. In contrast, surgical stress reduced the NK cell activity, the number of NK cells and down‐regulated the antigen presentation capability on monocytes. After surgery, followed by administration of endotoxin, the oxidative burst of granulocytes was stimulated while antigen presentation capability on monocytes was down‐regulated. Endotoxin prevented or reverted the postoperative suppression of NK cell activity.Conclusion:  Our two‐hit model shows that some cell types of the unspecific immune system exhibit an excessive inflammatory response (NK cells, granulocytes) while specific functions of other cell types (monocytes) are simultaneously diminished. This diversity makes a potential therapeutic immunomodulation very complex as some cell types would need to be down‐regulated while others need to be stimulated.
Comparison between intra‐articular bupivacaine with epinephrine and epinephrine alone on short‐term and long‐term pain after knee arthroscopic surgery under general anesthesia in day‐surgery patients
Authors: Toivonen J. , Pitko V.‐M. , Rosenberg P. H. 
Published: March 2003

Background: Postarthroscopy analgesia has been provided with intra‐articular bupivacaine, but reported results are conflicting regarding efficacy and the duration of analgesia. The immediate and long‐term effects of intra‐articular bupivacaine with epinephrine after arthroscopic knee surgery were therefore studied in a day surgery setting.Methods: 120 ASA I–II patients scheduled for arthroscopic knee surgery were given general anesthesia with spontaneous breathing via a laryngeal mask. In a randomized and blinded fashion half of them received, at the end of surgery, intra‐articularly 20 mL 0.5% bupivacaine with epinephrine (B + E‐group) and the other half 20 mL saline with epinephrine (S + E‐group). All patients received ketoprofen 100 mg i.v. during surgery and another 100 mg 2–3 h postoperatively. The patients were observed for about 4.5 h in the day surgery unit before discharge.Results: The results showed that in comparison with the S + E‐group, significantly fewer patients in the B + E‐group needed analgesics (P < 0.0001) and the amount required was also significantly less postoperatively, before discharge (about 4.5 h postoperatively) (P < 0.0001). The latency to the need for the first postoperative analgesic was shorter in the S + E‐group patients (P < 0.0001). At home, during seven days after discharge, the need for analgesic (oral ketoprofen 100 mg) was greater in the B + E‐group (P < 0.05), especially only during the second postoperative day, but the visual analoque pain scale (VAPS) scores were low with no differences between the groups. No complication occurred.Conclusion: It is concluded that a good postoperative pain control of intra‐articular bupivacaine with epinephrine was found only in the immediate postoperative period (i.e. before discharge) in a day‐surgery arthroscopic knee surgery patients.
Effect of delayed supine positioning after induction of spinal anaesthesia for caesarean section
Authors: Køhler F. , Sørensen J. F. , Helbo‐Hansen H. S. 
Published: March 2003

Background:  The study tested the hypothesis that the incidence of hypotension during spinal anaesthesia for caesarean section is less in parturients who remain in the sitting position for 3 min compared with parturients who are placed in the modified supine position immediately after induction of spinal anesthesia.Methods:  Spinal anaesthesia was induced with the woman in the sitting position using 2.8 ml hyperbaric bupivacaine 0.5% at the L3−4 or L2−3 interspace. Ninety‐eight patients scheduled for elective caesarean section under spinal anaesthesia were randomised to assume the supine position on an operating table tilted 10° to the left (modified supine position) immediately after spinal injection (group 0, n=52) or to remain in the sitting position for 3 min before they also assumed the modified supine position (group 3, n=46). Isotonic saline 2–300 ml was given intravenously over 15 min before spinal injection followed by 15 ml/kg over 15–20 min after induction of spinal anaesthesia. If the systolic blood pressure decreased to less than 70% of baseline or to less than 100 mmHg or if there was any complaint of nausea, ephedrine was given in 5 mg boluses intravenously every 2 min.Results:  The blood pressure decreased significantly in both groups following spinal injection (P<0.001). Blood pressure variations over time differed significantly between the two groups (P<0.05). However, the incidence of maternal hypotension before delivery was similar in the two groups. The difference was caused by the time to the blood pressure nadir being significantly shorter in group 0 compared with group 3 (9.1±4.5 min vs. 11.7±3.7 min, P<0.01). Similar numbers of patients received rescue with ephedrine before delivery: 35 (67%) in group 0 vs. 26 (57%) in group 3 (NS). The mean total dose of ephedrine before delivery was 10.9 mg in group 0 vs. 9.2 mg in group 3 (NS). There were no differences in neonatal outcome between the two groups.Conclusion:  At elective caesarean section, a 3‐min delay before supine positioning does not influence the incidence of maternal hypotension after induction of spinal anaesthesia in the sitting position with 2.8 ml of bupivacaine 0.5% with 8% dextrose.
Sevoflurane requirements during ambulatory surgery: a clinical study with and without AEP‐index guidance
Authors: Assareh H. , Anderson R. E. , Uusijärvi J. , Jakobsson J. 
Published: March 2003

Background: Several monitors have been developed to measure anesthetic depth. The auditory evoked response uses an auditory signal to actively test the level of brain activity. The aim of the present study was to determine whether sevoflurane titration with A‐line auditory guidance from the evoked potential monitor would reduce gas consumption and improve recovery times.Methods: Patients (n=60, aged 18–65 years) undergoing elective knee arthroscopy were randomized to titrate the main anesthetic sevoflurane with O2:N2O (1:2), either clinically (30 patients) or in combination with a target auditory evoked potential index of 30±5 (30 patients) using the A‐line monitor (version 1.4, Danmeter A/S; Odense, Denmark). Induction was supplemented with fentanyl, and randomized to 0.05, 0.10 and 0.15 mg immediately before propofol (10 in each group). Sevoflurane consumption and emergence times were the primary and secondary study end‐points.Results: Guidance from the A‐line monitor did not reduce the sevoflurane consumption time or the emergence, regardless of the fentanyl dose. However, it did reduce the time from the recovery room to discharge eligibility (P<0.05). Sevoflurane consumption decreased inversely with the fentanyl dose (P<0.01), with no impact on emergence times.Conclusion: The auditory evoked potential index provided by the A‐line monitor does not decrease sevoflurane consumption or emergence times for ambulatory knee arthroscopy.
Soda lime temperatures during low‐flow sevoflurane anaesthesia and differences in dead‐space
Authors: Luttropp H. H. , Johansson A. 
Published: March 2003

Background: Sevoflurane degrades during low‐flow anaesthesia to compound A, and high carbon dioxide absorbent temperatures cause increased degradation. The purpose of this investigation was to determine if larger tidal volumes, without increasing alveolar ventilation, decrease the temperature in the carbon dioxide absorber during low‐ and minimal‐flow sevoflurane anaesthesia.Methods: Prospective, randomized study, including 45 patients (ASA 1–2), scheduled for elective general or urology surgery. The patients were randomly assigned to one of three treatments. Patients in group 1 (NDS) received fresh gas flow of 1 litre/min without using additional dead‐space volumes. In group 2 (DS + 1.0), the patients received fresh gas flow of 1 litre/min using additional dead‐space volumes, placed between the Y‐piece and the HME, and patients in group 3 (DS + 0.5) received the same technique with a fresh gas flow of 0.5 litre/min. The soda lime temperatures, dead‐space volumes, end‐tidal carbon dioxide, sevoflurane concentrations, ventilation volumes and pressures, absorbent weight and ear temperatures were measured.Results: The maximum temperature of the soda lime was 44.1 ± 1.1° C in the NDS group, 37.8 ± 0.8° C in the DS + 1.0 group and 38.5 ± 2.7° C in the DS + 0.5 group (P<0.0001). The dead‐space volume between the Y‐piece the tracheal tube was 164 ± 69 ml in the DS + 1.0 group and 196 ± 15 ml in the DS + 0.5 group (P<0.05). The ventilator pressure were higher in the DS groups compared with the NDS group (P<0.001). Soda lime weight increased in all groups. End‐tidal carbon dioxide, sevoflurane concentrations and ear temperatures were similar between the groups.Conclusion: Increasing dead‐space volumes can reduce carbon dioxide absorber temperature during low‐ and minimal‐flow sevoflurane anaesthesia.
The pharmacodynamics and pharmacokinetics of mivacurium in children
Authors: Østergaard D. , Gätke M. R. , Berg H. , Rasmussen S. N. , Viby‐Mogensen J. 
Published: March 2003

Background: In children, onset time and duration of action of mivacurium are shorter than in adults. Some suggest that this is due to differences in plasma cholinesterase (pChe), whereas others indicate that there is no difference. The purpose of this study was to evaluate the pharmacodynamics and pharmacokinetics of mivacurium in phenotypically normal children aged 3–6 and 10–14 years old, respectively.Methods: Ten children aged 3–6 years and 10 children aged 10–14 years were studied during halothane anaesthesia. Before induction of anaesthesia, a bloodsample was drawn to measure the pChe activity and phenotype. The neuromuscular block was monitored at the thumb using train‐of‐four (TOF) nerve stimulation every 12 s and mechanomyography. The times to different levels of neuromuscular recovery following mivacurium 0.2 mg/kg were recorded. The concentrations in venous blood of the three isomers and the metabolites of mivacurium were measured.Results: No statistically significant difference was found in pChe activity or in the pharmacodynamics of mivacurium. The onset time was 1.4 min (0.8–1.9) median (range) and 1.3 min (1.1–1.9) and the time to first response to TOF nerve stimulation was 9.6 min (6.5–12.6) and 10.5 min (7.0–14.0) in young and older children, respectively. The pharmacokinetic data were too sparse to allow analysis of the two age groups separately (8 and 8 patients), hence the data were pooled. The median clearances of the cis‐cis, the cis‐trans, and the trans‐trans isomer were 5.5, 51.0 and 30.5 ml/kg/min, respectively.Conclusion: Our data indicate that there are no major differences in pharmacodynamics or pharmacokinetics of mivacurium between young (3–6 years) and older (10–14 years) children.