bluuebunny/crossref_metadata_2025_split huggingface dataset:
Midlatency auditory evoked potentials during anaesthesia with increasing endexpiratory concentrations of desflurane
Authors: Schwender D. , Klasing S. , Conzen P. , Finsterer U. , Pöppel E. , Peter K. 
Published: January 2009

Background. Under general anaesthesia with the volatile anaesthetics halothane, enflurane and isoflurane, midlatency auditory evoked potentials (MLAEP) are suppressed dose‐dependently. Therefore, MLAEP have been used to measure depth of anaesthesia and to indicate intraoperative awareness. Desflurane is a new volatile anaesthetic and its effects on MLAEP have not been studied previously.Methods. We have studied MLAEP during general anaesthesia with increasing endexpiratory concentrations of desflurane in 12 patients scheduled for elective gynaecological surgery. Auditory evoked potentials were recorded in the awake state and during anaesthesia with endexpiratory steady state concentrations of 1.5, 3.0, 4.5 and 6.0 vol %, of desflurane on vertex (positive) and mastoids on both sides (negative). Latencies of the peaks V, Na, Pa, Nb, Pl (ms) and amplitudes Na/Pa, Pa/Nb and Nb/Pl (μV) were measured.Results. In the awake state, MLAEP had high peak‐to‐peak amplitudes and a periodic waveform. During general anaesthesia with increasing endexpiratory concentration of desflurane, the latency of the brainstem response V increased only slightly. In contrast, MLAEP showed a marked dose‐dependent and statistically significant increase in latencies of Na, Pa, Nb and Pl and decrease in amplitudes of Na/Pa, Pa/Nb and Nb/Pl. Under 6.0 vol % of desflurane MLAEP were severely attenuated or even abolished.Conclusion. Based on these observations, endexpiratory concentrations of ≥4.5 vol % desflurane should suppress awareness phenomena such as auditory perceptions during anaesthesia.
Systemic and central effects of morphine on gastroduodenal motility
Authors: Thorn S.‐E. , Wattwil M. , Lindberg G. , Säwe J. 
Published: January 2009

Gastrointestinal side effects still constitute a major drawback in both acute and chronic use of opioids. The exact mechanism behind the gastrointestinal effects is not known, but experimental studies indicate both central and peripheral actions.In an attempt to clarify to what extent the systemic effects of morphine after epidural administration contribute to the action on gastrointestinal motility, a study aiming to resemble the situation with epidural morphine was designed. Twenty healthy male volunteers were randomly allocated to two groups. Group one (n = 10) received intrathecal (0.4 mg) and intramuscular (4 mg) morphine (IT‐IM‐group). Group two (n=10) received intrathecal (0.4 mg) morphine and i.m. saline (IT‐group).Gastroduodenal activity was assessed by gastric emptying, manometry and electrogastrography. The plasma and urine concentrations of morphine and its inactive metabolite morphine‐3‐ and active metabolite morphine‐6‐glucuronide were also determinedDuring the fasted state the gastrointestinal activity is characterised by a cyclic pattern with a duration of 80–120 min in the duodenum comprising three different phases with intense activity during Phase III. This pattern was seen in all volunteers. After the intrathecal administration the Phase III activity occurred significantly earlier in the IT‐IM group (median 31 min; IR 34 min) compared to IT group (82 min; 37 min) (P< 0.01). The number of Phase IIIs was higher in the IT‐IM group during the first 4 h after the morphine administration, compared to the IT group. However, after 6 h, there was no difference between the groups. The propagation velocity of Phase III decreased significantly in both groups (P< 0.001), but there was no difference between the groups. Tachygastria increased significantly with time in both groups. The acetaminophen absorption test showed that the area under the concentration curve (120 min) was significantly smaller in the IT‐IM group compared to the IT group (P< 0.05). There were no measurable plasma concentrations of morphine or the gluco‐ronidated metabolites M3G and M6G in the group that only received intrathecal morphine.This study showed that intrathecal morphine (0.4 mg) influenced gastroduodenal motility and that intramuscular morphine (4 mg) gave additional effects. These results might be applicable to the epidural situation and are indirect evidence that the gastroduodenal effects of epidural morphine are caused by both central and systemic effects of morphine.
No additional metal particle formation using the needle‐through‐needle combined epidural/spinal technique
Authors: Herman N. , Molin J. , Knape K. G. 
Published: January 2009

Background. Combined epidural/spinal analgesia utilizing a needle‐through‐needle technique has become very popular in anesthesia. However, findings of concave deformities at the orifice of Tuohy needles after spinal needle passage have raised concerns that metal fragments might be deposited within the epidural space. This study was proposed to investigate whether the needle‐through‐needle technique does produce metallic flecks.Methods. Ten unused Tuohy and Hustead epidural needles were inspected microscopically and photomicrographed prior to flushing saline through each into a single tissue culture well. After drying, a single pass was made with a 120 mm 24‐gauge Sprotte needle through each epidural needle to maximal extension while the orifice was within another tissue culture well. Each needle was again flushed into a third well before reexamination and photomicroscopy. Each of the wells was inspected for metallic particles by microscopy. Additional freshly unpackaged Tuohy needles were microscopically examined after exposure to a magnetic field.Results. Comparison of micrographs before and after needle experiments revealed concave deformities at the orifice of all the Tuohy and Hustead needles. No particles were observed in either of the two saline‐flushed wells or within the well in which the needle‐through‐needle passes were made. Inspection of unused Tuohy needles exposed to a magnetic field revealed metal filings “standing up” along the bevel of every needle examined.Conclusions. Metallic particles are not produced by the needle‐through‐needle technique. However, metal particles are an apparent contaminant of all epidural needles and are probably routinely introduced into patients when the needle is placed.
Influence of age on circulation and arterial blood gases in man
Authors: Gunnarsson L. , Tokics L. , Brismar B. , Hedenstierna G. 
Published: January 2009

Background.Modem data on the influence of age on hemodynamic and blood gas data in healthy subjects are sparse, especially in middle aged or older subjects. Most measurements have been done in patients during major surgery or in intensive care when the patients have one or more failing organ systems. This study reports on hemodynamics, blood gases and blood volume in healthy patients prior to anesthesia and elective surgery.Methods.A total of 116 subjects (92 males, 24 females) were investigated prior to anesthesia and elective surgery. No one had received any premedication or was taking regular medication. All subjects were in good physical condition, except for their surgical disease, and clinical examination and history did not reveal any sign of cardiopulmonary disease. Measurements were made of systemic and pulmonary vascular pressures, cardiac output, arterial blood gases and blood volume by131I‐Albumin distribution.Results.Cardiac output, stroke volume, and blood volume correlated to body surface. Relating these variables to body size eliminated almost all differences between the male and female groups. These variables, as well as both systemic and pulmonary artery systolic vascular pressures, were affected by increasing age. Pulmonary capillary wedge and right atrial pressures were not influenced by age. PaO2decreased with age from 14.0 kPa at 20 years to 11.3 kPa at 80, whereas PaCO2was unaltered. No effect of light smoking was found on pulmonary circulation or arterial blood gases. Significant correlations were found between blood volume on the one hand and body size and age on the other hand, but not in regard to sex.
Treatment of acute reflex sympathetic dystrophy with DMSO 50% in a fatty cream
Authors: Zuurmond W. W. A. , Langendijk P. N. J. , Bezemer P. D. , Brink H. E. J. , de Lange J. J. , van Loenen A. C. 
Published: January 2009

Acute Reflex Sympathetic Dystrophy (acute RSD) was defined using a reproducible classification. Elevated temperature of the affected extremity (“calor”), measured by the dorsal side of the observer's hand and mentioned by the patient, pain (“dolor”) measured by the Visual Analogue Scale (VAS), redness (“rubor”), edema (“tumor”) and limited active range of motion (“functio laesa”), all contributed to the classification system. Patients scoring 4 or 5 positive symptoms were considered to have acute RSD.A prospective, randomized and double blind study was performed in 32 patients, all suffering from acute RSD. In all of these patients the primary injury was the result of a previous accident. One patient was taken out of the study because of his surgery. The study involved treatment with a fatty cream with 50% dimethyl sulfoxide (DMSO, group A), or without DMSO (placebo, group B), both for 2 months. All patients received physiotherapy applied within pain limits.Application of the creams resulted in both groups in an improvement of RSD‐scores and VAS‐scores after 2 months. However, the improvement of the RSD score in patients of group A (DMSO‐group) was significantly (P<0.01) better compared to group B. The results suggest a certain activity of DMSO 50% cream in patients suffering from RSD and is, therefore, recommendable.
Malignant hyperthermia (MH) diagnostics: a comparison between the halothane‐caffeine‐and the ryanodine‐contracture‐test results in MH susceptible, normal and control muscle
Authors: Hartung E. , Koob M. , Anetseder M. , Schoemig P. , Krauspe R. , Hogrefe G. , Engelhardt W. 
Published: January 2009

Recent studies demonstrated different contracture responses in muscle from malignant hyperthermia susceptible (MHS) compared to normal (MHN) individuals following exposure to the plant alkaloid ryanodine in‐vitro. To confirm if ryanodine has a specific action in MHS muscle, the effect of a single concentration was investigated in skeletal muscle from MHS, MHN and control subjects using a new evaluation technique. In‐vitro contracture test (IVCT) and MH diagnosis were performed according to the European Protocol in 86 patients sent to us for MH diagnostic testing and in 24 controls. Viable fresh muscle bundles were exposed to a single bolus of ryanodine 1.0 μM. Contracture onset time (OTp: defined as the time (min) from administration of ryanodine to the start of a contracture as measured by a contracture exceeding predrug baseline height), and the time to an increase of the baseline height to 10 mN above the predrug level (10Tp) were recorded.29 patients were identified by IVCT to be MHS, 50 MHN, 7 MHE (equivocal) and 24 controls MHN. The indices from the ryanodine test separated all MHS (OTp: <16 min; 10Tp <27.4 min) from MHN (>18 and >27.7 min) and control subjects (>17.4 and >29 min). Values for MHE (equivocal) individuals ranged from 17.1 to 27.8 min for the OTp and from 32 to 49.2 min for the 10Tp. 5 patients with fulminant MH crises were included in the MHS group and showed the 95% confidence intervals (CI) of the median value ≤8.05min (OTp) and ≤13.35min (IOTP) for MHS. In contrast, CI of the median value for the control group were found to be ≥25.2min (OTp) and 43.15min (10Tp) for normal muscle.Thus the ryanodine test protocol showed markedly different contractures in MHS and MHN or control muscle. These results suggest that MHS muscle has a higher sensitivity to ryanodine. However, the protocol should be investigated for reproducibility and validation of thresholds by other laboratories. Ryanodine can help to improve MH diagnostic tests.
Early cerebral functional outcome after coronary artery bypass surgery using different acid‐base management during hypothermic cardiopulmonary bypass
Authors: Engflhardt W. , Dierks T. , Pause M. , Hartung E. 
Published: January 2009

Background: Cerebral injury can render meaningless an otherwise successful cardiac operation. As carbon dioxide management during hypothermic cardiopulmonary bypass has a major impact on cerebral blood flow during bypass, it may also influence postoperative cerebral function. The objective of this prospective, controlled, double‐blind study was to compare the effect of pH‐stat (temperature correction of blood gas analyses) or α‐stat (no temperature correction) on brain function.Methods: Cerebral function was assessed non‐invasively using neurological examination, a neuropsychological test battery, quantitative electroencephalogram and the cognitive evoked potential P300 preoperatively and on postoperative day 7 or 8. Forty‐five patients undergoing elective aortocoro‐nary bypass grafting in barbiturate/opiate anesthesia were randomised into a pH‐stat‐ (n=23) and an α‐stat‐group (n=22). Membrane oxygenators with arterial line filtration and non‐pulsatile flow at a perfussion pressure of 50–60 mmHg were used throughout.Results: One patient in each group developed a new paresis. Among 49 comparisons of cerebral function parameters, only 3 showed significant differences at the 5%‐level, i.e. exactly what is expected purely by chance. These differences were too small to be clinically relevant and favored either pH‐stat (theta‐amplitude) or α‐stat (subtest 3 of syndrome‐short‐test, number of mistakes in aiming).Conclusion: Under the bypass conditions of this study there was no difference in early cerebral functional outcome between pH‐ or α‐stat carbon dioxide management during hypothermic cardiopulmonary bypass.
Effect of nitrous oxide on human skeletal muscle function
Authors: Eiken O. , Tesch P. A. , Mejkavic I. B. 
Published: January 2009

Background: Nitrous oxide (N2O) is commonly administered in conjunction with parturition, which requires the performance of repeated high‐force voluntary muscle actions. Therefore, we examined the effect of a subanesthetic dose of N2O on the force‐velocity relationship of the quadriceps femoris muscle.Methods: Nine healthy subjects performed maximal voluntary muscle actions once while breathing air and once while breathing a normoxic gas mixture containing 35% (N2O). Peak torque of the knee extensors was measured during concentric muscle contractions at different angular velocities (30, 60, 90, 150 and 210°s‐1), and eccentric (30, 60, 90 and 150°s‐1) and isometric (knee‐joint angle=60°) muscle actions. Maximal angular velocity was determined during unloaded knee extensions.Results: N2O decreased peak torque at any given angular velocity. The overall decrease in peak torque averaged 4.8±2.2% (P<0.001). Likewise, N2O decreased maximal angular velocity by 5.7±4.3% (P<0.01). Thus, the impairment in muscle function induced by a 35% N2O is only minute and hence most likely of little significance in clinical practice.
Cytokines in stored red blood cell concentrates: promoters of systemic inflammation and simulators of acute transfusion reactions?
Authors: Kristiansson M. , Soop M. , Saraste L. , Sundqvist K. G. 
Published: January 2009

Background: The cytokine network has important implications for the systemic inflammatory and metabolic response in trauma and infection. Cytokines exogenously administered to traumatized and infected patients may have implications for the trauma response in these patients. The main objective of this study was to characterize red blood cell concentrates (RBCs) with regard to cytokine content.Methods: We investigated the concentrations of tumor necrosis factor α (TNF), interleukin‐1 β (IL‐1), interleukin‐6 (IL‐6) and interleukin‐8 (IL‐8) in sixteen units of RBCs stored at +4° C during 40 days. Samples from RBCs were taken every tenth day. Healthy volunteers were used as controls.Results: IL‐1 and IL‐8 in RBCs were increased compared to controls, P< 0.01 ‐ P < 0.001 and TNF in RBCs were increased on days 1 and 40 compared to controls, P < 0.05. During storage TNF was highest on day 1, 69 (< 3 ‐ 1060) pg/ml, median (range). IL‐1 concentrations increased during the period of storage from 5 (< 2 ‐ 205) pg/ml to 174 (< 2 ‐ 2180) pg/ml, P < 0.01. IL‐6 was 6 (< 2 ‐ 210) pg/ml on day 1 and did not change over the period of storage. IL‐8 was highest on day 40,164 (15 ‐ 790) pg/ml and compared to day 1 the concentrations were increased on day 10 and day 40, P < 0.05 for both comparisons.Conclusions: The results indicate the presence of TNF, IL‐1, IL‐6 and IL‐8 in stored RBCs, though there was a great variability over the period of storage and between units of RBCs. In some samples of RBCs the content of cytokines reached levels that may be anticipated to contribute to systemic inflammation and the symptomatology of acute transfusion reactions.
PCO2 electrodes at the surface of the kidney detect ischaemia
Authors: Tønnessen T. I. , Kvarstein G. 
Published: January 2009

Background: Under ischaemic (anaerobic) conditions there will be an accumulation of CO2 in the tissue secondary to a build up of protons that is buffered by HCO3‐. We reasoned that CO2 could be measured at the surface of the kidney by PCO2 electrodes to detect ischaemic conditions.Methods: Anaesthetized, mechanically ventilated pigs (25–30 kg) were investigated. Two acute porcine models, one of haemorrhagic shock and one of renal artery stenosis were used. Renal blood flow was gradually decreased, either by successive episodes of bleeding through the arterial cannula or by successive snaring of the renal artery.Results: In both models we found that with decreased blood flow but maintained aerobic metabolism (supply independence) PCO2 both at the surface of the kidney and in the renal vein increased by 2–3 kPa. Thus, the tissue‐venous PCO2 difference did not change much. At DO2crit, i.e., at the transition to supply‐dependent O2 consumption, the tissue PCO2 started to increase rapidly, as did the tissue‐venous PCO2 difference. This is compatible with the notion that a hallmark of ischaemia is decreased ability of the blood to transport away waste products because the contact between large parts of tissue and blood is virtually non‐existent. In the renal artery stenosis model kidney surface PCO2 values rose from a baseline of 6.6±0.6 kPa (mean±SEM) to a value near DO2crit of 10.6±0.8 kPa, reaching a final value of 29.9±3.5 kPa at no flow. PCO2 in the renal vein, however, reached a maximum of only 8.2±0.6 kPa. Numbers very similar to these were also found in the haemorrhagic model. The urine production decreased before the onset of ischaemia. When surface PCO2 values increased sharply indicating ischaemia, the urine production was zero. Lactate production by the kidney correlated very well with increasing tissue PCO2 values further corroborating that anaerobic metabolism was detected with the electrodes.Conclusion: We conclude that PCO2 electrodes placed at the surface of the kidney detect renal cortical ischaemia.
Reduced hypoxic chemosensitivity in partially paralysed man. A new property of muscle relaxants?
Authors: Eriksson L. I. 
Published: January 2009

Background: It was hypothesized that non‐depolarizing neuromuscular blocking agents impair hypoxic chemosensitivity in man.Methods: In thirty randomly allocated male volunteers the hypoxic and hypercarbic ventilatory responses were measured during partial paralysis (TOF ratio 0.70) due to either atracurium (n=10), pancuronium (n=10) or vecuronium (n=10).Results: Hypoxic ventilatory responses were depressed by 306, 287 and 296% (mean SD) at steady‐state infusion of atracurium, pancuronium and vecuronium, respectively. At a TOF ratio of >0.90, the HVR was not different from control measurements.Conclusion: It is concluded that non‐depolarizing neuromuscular blocking agents impair hypoxic ventilatory regulation. Further experimental studies are warranted to fully describe the mechanism(s) responsible for this interaction.
Recall of awareness during cardiac anaesthesia: influence of feedback information to the anaesthesiologist
Authors: Ranta S. , Jussila J. , Hynynen M. 
Published: January 2009

We interviewed 303 cardiac surgery patients to evaluate the incidence of intraoperative awareness with recall.First, we randomly interviewed 99 patients, of whom four patients (4%) reported awareness and recall. We informed the cardiac anaesthesiologists of the results of these interviews, and we also gave general information regarding means to reduce awareness and recall during general anaesthesia. Thereafter, we interviewed 204 consecutive cardiac surgery patients. Now, three of the patients (1.5%) had intraoperative awareness with recall. The reduction in the incidence from 4% to 1.5% was not significant. However, the doses of principal anaesthetic drugs had increased significantly between the two interview phases, while the dose of pancuronium, the main muscle relaxant used, had decreased significantly. Also, there was a significant increase in the number of anaesthesias where anaesthetic agents had been administered continuously instead of bolus or non‐continuous dosing techniques. Between the patients with awareness and recall and those without it, there was no difference in the doses of anaesthetic agents given. The patients with awareness were significantly younger than those not aware.In conclusion, with educational measures and vigilance over the problem, the incidence of intraoperative awareness during cardiac anaesthesia may be reduced. The incidence figure of 1.5% we observed is of the magnitude reported recently by others with modern cardiac anaesthesia techniques.
Propofol anaesthesia in spontaneously breathing paediatric patients during magnetic resonance imaging
Authors: Levatt A. , Colombo N. , Arosio E. M. , Savoia G. , Tommasino C. , Scialfa G. , Boselli L. 
Published: January 2009

Background:The aim of this study was to evaluate the use of propofol to induce and maintain anaesthesia in spontaneously breathing paediatric patients (age 2 weeks ‐ 11 years) during Magnetic Resonance Imaging (MRI) of the CNS.Methods:All patients were spontaneously breathing, without intubation, and received supplemental O2. Pulse rate, blood pressure (BP), electrocardiogram and EtCO2were recorded in all patients, and in 38 subjects SpO2was also monitored. Patients were divided in 2 groups according to their body weights: Group A (n=34, bwt ≤ 10 kg), and Group B (n=48, bwt> Id kg).Results:Dosage of propofol during the time of induction (from insertion of the i.v. cannula to positioning on the MRI table) was significantly higher in smaller children (Group A; 5.4 ± 2.2 (SD) mg/kg) as compared to children with bwt above 10 kg (Group B; 3.7 ± 1.6 mg/kg). Propofol dosage for maintenance of anaesthesia was significantly higher in smaller children (Group A: 10.1 ± 5.7 vs Group B: 7.1 + 3.0 mgkg‐1h‐1, P=0.003). During the time of induction, transient episodes of reduced BP (≤ 20%) occurred in 6 patients in Group A and 2 patients in Group B. During anaesthesia in Group B there was 1 episode of oxygen desaturation (95%), and 3 episodes of short and mild increases of EtCO2(≤ 52 mmHg). No other side effects occurred in any patient. MRI studies were successfully completed, only 3 sequences (Group A) had to be restarted.Conclusion:Propofol can be safely used for total intravenous anaesthesia in children undergoing MRI.