bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vitro contracture test for diagnosis of malignant hyperthermia following the protocol of the European MH Group: Results of testing patients surviving fulminant MH and unrelated low‐risk subjects
Authors: ØRDING H. , BRANCADORO V. , COZZOLINO S. , ELLIS F. R. , GLAUBER V. , GONANO E. F. , HALSALL P. J. , HARTUNG E. , HEFFRON J. J. A. , HEYTENS L. , KOZAK‐RIBBENS G. , KRESS H. , KRTVOSIC‐HORBER R. , LEHMANN‐HORN F. , MORTIER W. , NIVOCHE Y. , RANKLEV‐TWETMAN E. , SIGURDSSON S. , SNOECK M. , STIEGLITZ P. , TEGAZZIN V. , URWYLER A. , WAPPLER F. 
Published: January 2009

Background: Determination of sensitivity and specificity of the in vitro contracture test (IVCT) for malignant hyperthermia (MH) susceptibility using the European MH Group (EMHG) protocol has been performed in some laboratories but only on a small sample from the combined EMHG. Thus, the purpose of the present study was to determine combined EMHG sensitivity and specificity of the test.Methods: Results of IVCT of patients with previous fulminant MH and normal, low‐risk subjects (controls) were collected from 22 centresof the EMHG. IVCT was performed according to the EMHG protocol. Patients were included inthe study if the clinical crisis had a score of at least 50 points with the Clinical Grading Scale. Low‐risk subjects were included provided they did not belong to a family with known MH susceptibility, they had not developed any signs of MH at previous anaesthetics, and they did not suffer from any neuromuscular disease. For inclusion of both MH patientsand low‐risk subjects, at least 1 muscle bundle in the IVCT should have twitches of 10 mN(1 g) or more. For evaluation of individual tests, only muscle bundles with twitch heights of 10 mN (1 g) or more were used.Results: A total of 1502 probands had undergone IVCT because of a previous anaesthesia with symptoms and signs suggestive of MH. Of these, 119 had clinical scores of 50 and above. From these 119 MH‐suspected patients and from 202 low‐risk subjects, IVCT data were collected. Subsequently, 14 MH‐suspected patients were excluded from further analysis for thefollowing reasons: In 3 patients, the suspected MH episode could be fully explained by diseases other than MH; in 11 MHS patients, IVCT was incomplete (n=l), data were lost (n=3), or none of the muscle bundles fulfilled twitch criteria (n=7). Of the remaining 105 MH‐suspected patients, 89 were MHS, 10 MHEh, 5 MHEc, and one MHN. Thus, we observed a diagnostic sensitivity of the IVCT of 99.0% if the MHE group is considered susceptible(95% confidence interval 94.8–100.0%). Of the 202 low‐risk subjects, 3 were MHS, 5 MHEh, 5 MHEc, and 189 MHN. This gives a specificity of the IVCT of 93.6% (95% confidence interval 89.2–96.5%).Conclusion: The IVCT for diagnosis of MH susceptibility in Europe has a high sensitivity and a satisfactory specificity.
4‐chloro‐m‐cresol test ‐ a possible supplementary test for diagnosis of malignant hyperthermia susceptibility
Authors: ØRDING H. , GLAHN K. , GARDI T. , FAGERLUND T. , BENDIXEN D. 
Published: January 2009

Background: In vitro contracture test (IVCT) for diagnosis of MH in our laboratory has a sensitivity of 100% and a specificity of 93%. The results are equivocal in 10–15%, and supplementary tests may thus be required. We have tested the hypothesis that 4‐chloro‐m‐cresol (4‐cmc) may be useful for a supplementary test.Methods: Muscle from 41 consecutive patients from 7 families undergoing diagnostic muscle biopsy with IVCT was exposed in vitro to increasing concentrations of 4‐cmc (25, 50, 75, 100, 150, and 200 umol 1‐‐1), and the force development recorded. Diagnosis of MH susceptibility was made with standard halothane and caffeine tests and included as results MHS (MH susceptible), MHN (MH negative), and MHE (equivoval result).Results: At all concentrations of 4‐cmc, the increase in baseline force was significantly greater in the MHS group compared to the MHN group (P < 0.05). Muscle from 15 MH‐susceptible (MHS) patients responded to 4‐cmc with increasing force at a threshold concentration of 75 umol 1‐‐1 or less, whereas muscle from 23 MH‐non‐susceptible (MHN) patients had thresholds of 100 umol 1‐‐1 or more. The accuracy of the chlorocresol test was thus 100% (95% confidence limits 90.75–100%) at a threshold of 75 umol 1‐‐1. Amplitude of contractures at 2 mmol 1‐‐1 caffeine was not different from contractures at 75 umol 1‐‐1 of 4‐ cmc in either the MHS or the MHN group (P > 0.05). In vivo concentrations of chlorocresol from clinical use of insulin and somatro‐pin are estimated to be 20 times less than the threshold concentration and thus these drugs seem safe in MH patients.Conclusion: 4‐chloro‐m‐cresol may be a suitable aid to clarify puzzling results of standard testing of MH susceptibility.
Incidence of awareness in total i.v. anaesthesia based on propofol, alfentanil and neuromuscular blockade
Authors: NORDSTRÖM O. , ENGSTRÖM A. M. , PERSSON S. , SANDIN R. 
Published: January 2009

Background: There is no reliable technique for monitoring drug concentrations in totali.v. anaesthesia (TIVA) with muscle relaxation. An increased risk of awareness with TIVAhas been stated as a possible drawback (1, 2). The present study was conducted in order toassess the incidence of conscious awareness in TTVA based on propofol, alfentanil and neuromuscular blockade.Methods: One thousand patients anaesthetized with TIVA based on propofol, alfentanil, and neuromuscular blockade were subjected postoperatively to a structured interview for conscious awareness on two separate occasions: on discharge from the post‐anaesthesia care unit, and the day after anaesthesia. Five hundred of these patientswere also interviewed a third time, approximately 1 week later.Results: Two cases of awareness were detected (0.2%). One of these was identified immediately after extubation. The second patient had no memory of intraoperative events or dreams at the first interview, recalled a bad dream on the day after, and had explicit recall of intraoperative events at the interview 8 days later. In both cases, haemodynamic signs of inadequate anaesthesia were present. The incidence of conscious awareness in this study is similar to the lowest previously reported incidence of awareness following general anaesthesia in patientswho had been paralyzed and thereafter subjected to a structured postanesthesia interview.Conclusions: If the true incidence of conscious awareness is to be determined, interviewsmust be extended beyond the first postoperative day. Our study indicates that if appropriate dosing of propofol and alfentanil are adhered to, and proper action is taken in case of haemodynamic alterations suggestive of inadequate anaesthesia, the incidence of conscious awareness in non‐cardiac TIVA with neuromuscular blockade is low.
Cerebral normoxia in the rhesus monkey during isofluraneor propofol‐induced hypotension and hypocapnia, despite disparate blood‐flow patterns
Authors: ENLUND M. , ANDERSSON J. , HARTVIG P. , VALTYSSON J. , WIKLUND L. 
Published: January 2009

Background: Due to a few reports of cerebral dysfunction in connection with isoflurane‐induced hypotension and concomitant hypocapnia, positron emission tomography (PET) was used to measure cerebral oxygenation and blood flow during similar conditions with isoflurane or propofol.Methods: The short‐lived radionuclide 15O was used for measurement of cerebralmetabolic rate of oxygen (CMRO2), cerebral blood flow (CBF) and oxygen extraction ratio (OER) regionally in rhesus monkeys during normotensive/normocapnic and hypotensive/hypocapnic conditions, mean arterial pressure 100–110 and 50–65 mmHg and PaCO2 4.4–5.4 and 3.4‐4.4 kPa, respectively. Isoflurane or propofol anaesthesia was given (n=4 in both groups), supported with 70% nitrous oxide and preceded by ketamine anaesthesia (baseline).Results: PET revealed wide variations in CBF between regions during isoflurane anaesthesia, particularly in comparison with propofol anaesthesia, while rCMRO2 decreased globally in a dose‐dependent manner during both isoflurane and propofol anaesthesia. The metabolism‐flow coupling was intact during propofol but not during isoflurane anaesthesia. Hypotension reduced rCBF, and rOER increased globally with both study drugs when changing from normo‐ to hypotension. However, this rOER increase was not significant when using PaCO2 as a co‐variate, and rOER was never above an arbitrary limit for hypoxia of 70%. Thus, hypocapnia, rather than hypotension, was responsible for the somewhat higher rOER measured.Conclusion: PET indicated adequate cerebral oxygenation during isoflurane and propofol anaesthesia, despite disparate blood‐flow patterns. Hypotension and concomitant moderate hyperventilation reduced rCBF, but did not result in hypoxia.
Neurohistopathological findings after continuous intrathecal administration of morphine or a morphine/ bupivacaine mixture in cancer pain patients
Authors: WAGEMANS M. F. M. , VAN DER VALK P. , SPOELDER E. M. , ZUURMOND W. W. A. , LANGE J. J. DE 
Published: January 2009

Background: As the number of terminal cancer patients receiving continuous intrathecalinfusion of opioids and local anesthetics for relief of pain increases, we decided to investigate the post‐mortem findings of the spinal cord, meninges and nerve roots of patients after continuous intrathecal administration of morphine and combined with bupivacaine.Methods: Neurohistopathological findings were obtained from 10 cancer patients [2 men and 8 women, 29–69 (median 52) yrs old] and 4 controls [4 men, 46–75 (median 64) yrs old]. The cancer patients had been treated for a mean of 98 (range 8–452) d with morphine/NaCl 0.9% or morphine/bupivacaine, administered through a polyamide lumbar catheter. Concomitant radiation therapy and chemotherapeutic drug had been given to 5 and 6 patients, respectively. Cumulative doses of morphine ranged from 22 to 3895 mg, those of bupivacaine from 0 to 3250 mg and of sodium metabisulfite (antioxidant) from 0.6 to 97.4 mg.Results: No macroscopic abnormalities of the catheter tract, dura, leptomeninges, nerve roots or spinal cord were found. Microscopically, focal foreign body giant cells were seenin 2 cases in the area of the catheter pathway both without any sign of inflammation. In one case treated for 103 d, an intrathecal reaction was found. This consisted of small aggregates of lymphocytes predominantly in the leptomeninges and focally in the cord parenchyma. No abnormalities were found in the other cases when using hematoxylin‐eosin and Kluver or Bodian stained specimens, indicating neither myelin nor axonal damage. Microglial reactions were similar in both cancer patients and controls.Conclusion: The discrete and limited neurohistopathological findings in both catheter patients and controls suggest that intrathecal infusion of morphine and bupivacaine via a polyamide catheter is devoid of significant neurotoxic effects in cancer patients.
Suppression of acetylcholine‐induced relaxation by local anesthetics and vascular NO‐cyclic GMP system
Authors: MINAMOTO Y. , NAKAMURA K. , TODA H. , MIYAWAKI I. , KITAMURA R. , VINH V. H. , HATANO Y. , MORI K. 
Published: January 2009

Background:Local anesthetics have been demonstrated to attenuate acetylcholine‐induced relaxation of vascular smooth muscle, but the mechanism responsible has not been elucidated. The present study was undertaken to ascertain whether this effect of local anesthetics is due to suppression of the vascular nitric oxide (NO)‐cyclic GMP (cGMP) system.Methods:Isolated rat aortae were cut into helical strips and mounted in bathing solution to measure isometric tension changes. They were precontracted with phenylephrine (0.3 μM)then exposed to cumulative concentrations of relaxants including acetylcholine, sodium nitroprusside (SNP) and papaverine, in the absence or presence of local anesthetics. Aortaefor cGMP measurements were cut longitudinally into pairs of strips and bathed in the solution without tension. In the absence or presence of anesthetics, they were stimulated with acetylcholine or SNP, and the cGMP content of each strip was radioimmunoassayed.Results:Acetylcholine‐induced, endothelium‐dependent relaxation of phenylephrine‐precontracted aortae was attenuated by lidocaine (30–300 μM), tetracaine (10–30 μM), bupivacaine (10–100 μM) and ropivacaine (30–100 μM). SNP‐inducedrelaxation was attenuated by lidocaine (300 μM), tetracaine (30 μM), bupivacaine (10–100 μM) and ropivacaine (30–100 μM). Papaver‐ine‐induced relaxation was attenuated by lidocaine (300 μM), bupivacaine (30–100 μM) and ropivacaine(30–100 μM), and augmented by tetracaine (30 μM). Cyclic GMP levels in acetylcho‐line‐stimulated aortae were reduced significantly by lidocaine (300 μM), tetracaine(100 μM) and bupivacaine (300 μM) treatment, but not by ropivacaine (300 μM). SNP‐stimulated cGMP levels were reduced by tetracaine (100 μM) but not by any other anesthetics at the concentrations tested.Conclusion:We conclude that lidocaine, tetracaine and bupivacaine suppress acetylcholme‐stimulated formation of cGMP. However, the attenuation of acetylcholine‐induced relaxation by local anesthetics is not totally ascribable to reduced cGMP levels.
Analgesia after upper abdominal surgery using extradural administration of a fixed dose of buprenorphine in combination with lignocaine given at two infusion rates: A comparative study
Authors: WAJIMA Z. , SHITARA T. , ISHIKAWA G. , KANEKO K. , INOUE T. , OGAWA R. 
Published: January 2009

Background: Extradural administration of combinations of local anaesthetics and opioids are frequently employed for postoperative pain relief. There is a scarcity of data on the analgesic effects of variations of the dose of local anaesthetic drug admixed to a fixed dose of opioid.Methods: Twenty‐four patients were investigated after elective upper abdominal surgery. During closure of the abdomen, 2% mepivacaine (8 ml) with buprenorphine 0.1 mg (0.5 ml) was given extradurally. After extubation, patients were randomly allocated to receive continuous extradural infusion of a fixed dose of buprenorphine (0.017 mg/h) in combination with 2% lignocaine at either 2.1 ml/h (low rate group, n = 14) or 6.3 ml/h (high rate group, n = 10). Postoperative pain at rest was assessed using visual analogue scale (VAS) scores and pain at movement by Prince Henry Pain Scale (PHPS)scores. Venous plasma lignocaine concentrations were measured.Results: VAS scores at rest were similar in the two groups at 3 h postoperatively, whereas at 6–24 h postoperatively, VAS scores were higher in the low rate group than in the high rate group. PHPS scores were similar in the two groups at 3 h and at 18 h postoperatively, whereas at 6, 9, 12 and 24 h postoperatively, PHPS scores were higher in the low rate group than in the high rate group. Plasma lignocaine concentrations were higher at23 h postoperatively in the high rate group than at 16 h in both groups, and at 23 h in the low rate group. At 3 h postoperatively, both the systolic and diastolic arterial pressures were higher in the low rate group than control values obtained on admission. Side effects were observed in one patient in the low rate group who complained of dizziness, andin one patient in the high rate group who complained of nausea.Conclusions: When added to a fixed dose of buprenorphine, continuous extradural infusion of 2% lignocaine at high rate provides better postoperative analgesia than when given at low rate without producing significant side effects.
Two cases of fatal air embolism in children undergoing scoliosis surgery
Authors: SUTHERLAND R. W. , WINTER R. J. 
Published: January 2009

Venous air embolism during surgery is a rare but important complication and can be rapidly fatal. We present two cases of fatal air embolism in the prone position occurring in small children undergoing surgery for progressive scoliosis.Venous air embolism is a rare complication in the prone position. This is thought to be because in this position there is virtually no gravitational gradient between the site of surgery and the right atrium.The possible sites of entry of air and ways that this may be minimized are discussed.
Blockade of endogenous nitric oxide production results in moderate hypertension, reducing sympathetic activity and shortening bleeding time in healthy volunteers
Authors: ALBERT J. , SCHEDIN U. , LMDQVIST M. , MELCHER A. , HJEMDAHL P. , FROSTELL C. 
Published: January 2009

Background: Short‐term infusion of NG‐monomethyl‐L‐arginine (L‐NMMA) reversibly inhibits endogenous nitric oxide (NO) production in humans. We studied responses to more long‐lasting (60 min) infusions, at doses high enough to cause effective inhibition of endogenous NO.Results: L‐NMMA significantly elevated mean arterial pressure by 123%, due to an increase in systemic vascular resistance. Cardiac output decreased by 233%, due to a decrease in stroke volume. Pulmonary vascular resistance (P < 0.05) increased, but mean pulmonary arterial pressure was stable. Forearm vascular resistance (P < 0.05) decreased. Bleeding time was shortened by 31 4% (P < 0.01). L‐NMMA infusion reduced NO concentrations in nasal air by 6422% (RO.01). Arterial pressure remained elevated and nasal NO remained depressed 90 min after the infusion, whereas most other responses were reversed at that time. Plasma cGMP showed only minor changes. Plasma norepinephrine decreased, suggesting reflexogenic inhibition of sympathetic activity, whereas epinephrine levels were low and stable throughout the experiment.Conclusion: Dosage of (13.5 mg · kg‐1 in 60 min) L‐NMMA infusion in humans was well tolerated. Pronounced and long‐lasting inhibition of endogenous NO production, as evidenced by measurements in nasal air, resulted in unevenly distributed vasoconstriction, a transient decrease in cardiac output, and reflexogenic sympathetic withdrawal. Furthermore, bleeding time was shortened, suggesting platelet activation.Methods: Eight healthy volunteers had catheters (pulmonary, arterial and venous) placed. Measurements included hemodynamics, endogenous NO levels in nasal air, bleeding time, and cyclic guanosine monophosphate (cGMP) and catecholamines in plasma. L‐NMMA was infused at 0.3 mg · kg‐l · min‐1 during 30 min, followed by 0.15 (n=6) or 0.3 (n=2) mg · kg‐1 · min‐1 during 30 min.
Effect of thoracic epidural anaesthesia on ventilation= perfusion distribution and intrathoracic blood volume before and after induction of general anaesthesia
Authors: HACHENBERG T. , HOLST D. , EBEL C. , PFEIFFER B. , THOMAS H. , WENDT M. , HEDENSTIERNA G. 
Published: January 2009

Background: Gas exchange is impaired during general anaesthesia due to development of shunt and ventilation‐perfusion mismatching. Thoracic epidural anaesthesia (TEA) may affect the mechanics of the respiratory system, intrathoracic blood volume and possibly ventilation‐perfusion (VA/Q) distribution during general anaesthesia.Methods: VA/Q relationships were analyzed in 24 patients undergoing major abdominal surgery. Intrapulmonary shunt (Qs/ QT), perfusion of “low” VA/Q areas, ventilation of “high VA/ regions, dead space ventilation and mean distribution of ventilation and perfusion were calculated from the retention/excretion data of six inert gases. Intrathoracic blood volume (ITBV) and pulmonary blood volume (PBV) were determined with a double indicator technique. Recordings were made before and after administration of 8.5±1.5 ml bupivacaine 0.5% (n=12) or 8.3±1.8 ml placebo (n=12) into a thoracic epidural catheter and after induction of general anaesthesia.Results: Before TEA, QS/QT was normal in the bupivacaine group (222%) and the placebo group (23%). TEA covering the dermatomal segments T 12 to T 4 had no effect on VA/Q relationships, ITBV and PBV. After induction of general anaesthesia S/T increased to 84% (bupivacaine group, P < 0.05) and to 72% (placebo group, P < 0.05). ITBV and PBV decreased significantly to the same extent in the bupivacaine group and the placebo group.Conclusions: TEA has no effect on VA/Q distribution, gas exchange and intrathoracic blood volume in the awake state and does not influence development of S/T and VA/Q inequality after induction of general anaesthesia.
Ropivacaine 7.5 mg/ml for elective Caesarean section. A clinical and pharmacokinetic comparison of 150 mg and 187.5 mg
Authors: IRESTEDT L. , EMANUELSSON B‐M. , EKBLOM A. , OLOFSSON C. , REVENTLID H. 
Published: January 2009

Background: The new, long‐acting local anaesthetic ropivacaine has shown less systemic toxicity than bupivacaine and a concentration of 7.5 mg/ml can therefore be used for epidural anaesthesia in Caesarean section. The present pilot study was undertaken to find indications for an optimal dosage by comparing the clinical effects, quality of anaesthesia and pharmacokinetics of ropivacaine 150 mg (lower dose=LD) vs 187.5 mg (higher dose=HD) for women undergoing elective Caesarean section under epidural anaesthesia.Methods: Sixteen full‐term women scheduled for elective Caesarean section in two equal‐sized consecutive groups received 20 or 25 ml ropivacaine epidurally in this non‐randomised, open study. Study parameters included sensory and motor blockade, circulatory response, intraoperative pain and discomfort, neonatal evaluation and pharmacokinetic determinations.Results: Block height varied between T5 and T2 in the LD group, whereas the HD group produced 4 unnecessarily high blocks (C8 in 3 women and C7 in 1 woman). Surgical anaesthesia was excellent in both groups. Circulatory stability was pronounced in the LD group (no ephedrine given), while 4 women required ephedrine in the HD group. Neonatal outcome as judged by Apgar scores, umbilical blood gas determinations and NACS scores were excellent in both groups. The plasma concentration‐time profiles indicated linearity in the concentration range studied, with similar clearance values to those reported previously. Pla‐cental drug equilibrium was rapid; however, the foetal drug exposure depended on intrauterine exposure time.Conclusions: 20–25 ml ropivacaine 7.5 mg/ml produced very satisfactory conditions for elective Caesarean section under epidural anaesthesia. In this small population, 150 mg ropivacaine seemed optimal, while 187.5 mg produced unnecessarily extended block height in 50% of the women.
Desflurane increases brain tissue oxygenation and pH
Authors: HOFFMAN W. E. , CHARBEL F. T. , EDELMAN G. 
Published: January 2009

Background Desflurane anesthesia can produce cerebral metabolic depression and increase cerebral blood flow. We evaluated the effect of desflurane on brain tissue oxygen pressure (PO2), carbon dioxide pressure (PCO2) and pH during neurosurgery.Methods: Following a craniotomy, the dura was opened and a Paratrend 7 sensor, which measures PO2, PCO2, pH and temperature, was inserted into brain tissue. In 6 control patients in group 1, anesthesia was maintained constant with 3% end‐tidal desflurane over 60 min, including a 30‐min stabilization period. In group 2, 9 patients were ventilated with 3% desflurane under baseline conditions. After a 30‐min stabilization period, baseline tissue gases and pH were measured and end‐tidal desflurane was increased to 6% and then 9% for 15‐min intervals. Mean arterial pressure (MAP) was maintained with intravenous phen‐ylephrine.Results: Under baseline conditions, cardiovascular and brain tissue measures were similar between the 2 groups. Increasing end‐tidal desflurane from 3% to 9% produced burst‐suppression EEG in all patients and significantly increased tissue PO2 and pH and decreased PCO2. No parameters changed significantly in the control group during steady‐state anesthesia.Conclusion: These results show that 9% desflurane can improve brain tissue metabolic status before temporary brain artery occlusion if cerebral perfusion pressure is maintained. This may be particularly important in patients with symptoms of ischemia before surgery.