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Biomedical subjects

C Meistelman

Publications and source records attributed to C Meistelman.

At least 37 records · Page 2Linked to original sources
PubMed2000

Evaluation of donor cardiac function for heart transplantation: experience of a French academic hospital.

OBJECTIVES: The diagnostic and therapeutic approaches for evaluation and management of cardiac function in brain-dead patients vary from country to country. The aim of the present study was to describe the results of the evaluation of brain-dead patients as potential cardiac donors in a French teaching hospital that manages the largest number of brain-dead patients in France. METHODS: Demographic parameters, the causes of brain death, clinical evolution, hemodynamic parameters, doses of inotropic and/or vasopressive drugs, the results of echocardiographic examination, and several biochemical markers of myocardial cell injury were retrospectively collected. RESULTS: Seventy-one consecutive brain-dead patients admitted to the intensive care unit of the Academic Hospital of Nancy from October 1st, 1998 to September 30, 1999 were analyzed. Twenty-nine patients were considered as potential heart donors: 22 males and 7 females aged 33 +/- 3 years (Mean + SEM). The cause of brain death was head trauma in 17 cases (59%), cerebrovascular disease in 10 cases (34%), and cerebral anoxia related to cardiac arrest in 2 cases (7%). Eighteen hearts (18/29 or 66%) were harvested and transplanted with a favorable outcome at one month in 17 cases. In 11 cases, the heart was not harvested, nine (9/29 or 31%) because of myocardial dysfunction upon subsequent echocardiographic examination and 2 because of the lack of matched recipients. CONCLUSION: Comparison of these results with those of other groups suggests that hormonal substitution with insulin and triiodothyronine in the presence of myocardial dysfunction could be of potential interest to correct myocardial dysfunction and increase the number of donor hearts.

Academic Medical Centers↗
PubMed1999

[Pharmacodynamics and safety of mivacurium in infants and children under halothane-nitrous oxide anesthesia].

OBJECTIVES: To determine pharmacodynamic effects and safety of mivacurium in paediatric patients. STUDY DESIGN: Multicentric, prospective, open, non-randomized study. PATIENTS: Forty-eight three-month-old to eight-year-old physical class ASA I or II children. METHOD: Anaesthesia was induced and maintained with halothane and nitrous oxide. Tracheal intubation was performed without a neuromuscular blocking agent. Neuromuscular blockade was measured with a strain force transducer after train-of-four stimulation of the ulnar nerve at the wrist every ten seconds. A single bolus dose of mivacurium (0.2 mg.kg-1) was injected during 15 seconds in patients allocated into three groups. Group 1: three to 12-month-old infants (n = 15), group 2: one- to three-year-old children (n = 16) and group 3: three- to eight-year-old children (n = 17). Onset and recovery parameters were measured in each patient. Heart rate and noninvasive arterial blood pressure were recorded every minute for five minutes after mivacurium injection. RESULTS: Following halothane administration for 29 and 32 min, and a FEThalothane = 1 vol%, mivacurium (0.2 mg.kg-1) determined a 100% neuromusmcular blockade in all patients. The onset time was 71 +/- 34 s (mean +/- SD) in all patients and did not differ between groups. Time to 25% and 95% recovery of the first twitch and recovery index for all the patients were 12 +/- 3 min, 19 +/- 5 min and 4 +/- 2 min respectively and did not differ between groups. No prolonged paralysis was observed. No significant changes of HR and BP occurred. CONCLUSIONS: Following 0.2 mg.kg-1 of mivacurium in patients aged between three months to eight years, a complete blockade occurs with a rapid onset time and a short duration of action, without significant cardiovascular effect.

Anesthetics, Inhalation↗
PubMed1997

Monitoring orbicularis oculi predicts good intubating conditions after vecuronium in children.

PURPOSE: The aim of the study was to compare visual estimation of onset of neuromuscular blockade at both the adductor pollicis (AP) and the orbicularis oculi (OO) in children and to determine if monitoring the OO could predict good intubating conditions during vecuronium-induced neuromuscular blockade. METHODS: Thirty ASAI--II children (1.5-9 yr) were studied. Anaesthesia was induced with 6-8 mg.kg-1 thiopentone. The ulnar nerve at the wrist and the temporal branch of the facial nerve were stimulated every 10 sec using train-of-four (TOF) stimuli. Vecuronium, 0.15 mg.kg-1, was administered as a bolus. The responses at both the OO and the AP were evaluated visually. Patients were randomly divided into two groups. In the AP group (n = 15), the trachea was intubated when the AP was completely blocked. In the OO group (n = 15), intubation was performed when the OO was completely blocked. Intubating conditions were scored on a scale of 1 to 4. RESULTS: All the patients had complete blockade at both the orbicularis oculi and the adductor pollicis. In the two group, time from injection of vecuronium to complete neuromuscular blockade was shorter at the orbicularis oculi than at the adductor pollicis, 1.5 +/- 0.5 min vs 2.3 +/- 0.7 min, respectively, (P < 0.05; mean +/- SD) in the AP group, 1.7 +/- 0.3 min vs 2.3 +/- 0.8 min, respectively in the OO group (P < 0.05). Intubating conditions were excellent in all patient except one, where it was rated as good. They did not differ between groups. CONCLUSION: Following administration of 0.15 mg.kg-1 vecuronium in children, monitoring of the OO can detect good intubating conditions 0.7 min earlier than with monitoring of the AP.

Child↗
PubMed1997

ORG 9487 neuromuscular block at the adductor pollicis and the laryngeal adductor muscles in humans.

BACKGROUND: ORG 9487 is a new steroidal nondepolarizing muscle relaxant with a rapid onset of action. This study was designed to determine the neuromuscular blocking profile of ORG 9487 at the adductor muscles of the larynx and the adductor pollicis. METHODS: In 30 adults, anesthesia was induced with propofol (2-5 mg/kg) and fentanyl (2-3 microg/kg). After train-of-four stimulation, the block of the laryngeal adductor muscles was evaluated by measuring the pressure changes in the cuff of the tracheal tube placed between the vocal cords, and the force of the contraction of the adductor pollicis was measured with a force transducer. Patients were randomly allocated to receive ORG 9487 at intravenous bolus doses of 0.75, 1.5 or 2 mg/kg (n = 10 in each group). RESULTS: Time to peak effect was significantly shorter at the vocal cords than at the adductor pollicis muscle (P < 0.001). Onset time at the vocal cords was 62 +/- 16 s, 62 +/- 13 s, and 52 +/- 14 s (mean +/- SD) after doses of 0.75, 1.5, and 2 mg/kg, respectively (not significant). Onset time at the adductor pollicis muscle was 126 +/- 33 s, 96 +/- 20 s, and 82 +/- 21 s after 0.75, 1.5, and 2 mg/kg doses, respectively (P < 0.001). Maximum block was significantly less intense at the vocal cords than at the adductor pollicis muscle (69 +/- 15% vs. 94 +/- 4% after 0.75 mg/kg; 86 +/- 7% vs. 97 +/- 4% after 1.5 mg/kg; and 91 +/- 5% vs. 99 +/- 1% after 2 mg/kg). After 1.5 mg/kg duration to 25%, recovery was 3.7 +/- 2.2 min versus 10.2 +/- 2.5 min at the vocal cords and the adductor pollicis muscle, respectively, and 75% recovery occurred at 9.7 +/- 3.7 min at the vocal cords and at 18.3 +/- 5.2 min at the adductor pollicis muscle. CONCLUSIONS: ORG 9487 has a rapid onset of action at the laryngeal adductor and the adductor pollicis muscles. Onset and duration of action are faster at the vocal cords than at the adductor pollicis muscle. However, the maximum block obtained at the laryngeal muscles was less than at the adductor pollicis, regardless of the dose of ORG 9487.

Adult↗
PubMed1997

Neuromuscular blockade: is it still useful in the ICU?

Neuromuscular relaxants may be administered to ICU patients for days or weeks. The most frequent indications are facilitation of mechanical ventilation and management of neurosurgical patients after severe head injury. Tachyphylaxis can be observed in ICU patients but the major problem remains the prolonged weakness which can occur after long-term administration of muscle relaxants. The mechanisms are still poorly understood and under investigation. Although neuromuscular monitoring provides guidelines for the administration of muscle relaxants in critically ill patients, it does not prevent the development of a myopathy.

Humans↗
PubMed1996

[Effects of propofol on blood concentration of cyclosporine].

OBJECTIVE: This study was designed to assess whether propofol modifies the blood concentrations of cyclosporine and lipoproteins, which bind cyclosporine. STUDY DESIGN: Prospective open study. PATIENTS: Fifteen consecutive grafted patients, scheduled for surgery allowing them to resume their oral treatment postoperatively. Their immunosuppressive treatment, included cyclosporine (Cy A), at a steady-state dosage. METHODS: Blood samples were drawn and residual Cy A blood concentrations were measured the days before and after anaesthesia and before and immediately after discontinuing the propofol infusion. Serum triglycerides, cholesterol, high-density lipoprotein (HDL) concentrations were measured before and immediately after discontinuing the propofol infusion. RESULTS: The 15 patients were given propofol by infusion for 30-210 min (mean 85 +/- 59 min). They received a total dose of propofol of 696 +/- 497 mg, a total fentanyl dose of 175 +/- 82 micrograms, and a total midazolam dose of 2.8 +/- 0.8 mg. The residual cyclosporine blood concentrations were similar the day before (142 +/- 47 ng.mL-1) and following anaesthesia (128 +/- 46 ng.mL-1) (P = 0.08). Serum cholesterol concentrations were not significantly influenced by propofol infusion, but serum triglycerides levels increased (1.46 +/- 0.66 vs 1.97 +/- 0.81 g.L-1), and HDL and LDL levels decreased (0.54 +/- 0.20 vs 0.47 +/- 0.18 g.L-1; 1.44 +/- 0.42 vs 1.28 +/- 0.37 g.L-1). CONCLUSION: Propofol by infusion does not modify the cyclosporine concentration. It is concluded that propofol may be a suitable agent for intravenous anaesthesia in cyclosporine treated patients, provided a close postoperative monitoring of cyclosporine blood concentrations is maintained.

Adult↗
PubMed1996

Mivacurium neuromuscular block at the adductor muscles of the larynx and adductor pollicis in humans.

BACKGROUND: Laryngeal muscles must be paralyzed for tracheal intubation. Time to peak effect (onset time) is shorter and intensity of blockade is less at laryngeal muscles compared with the adductor pollicis. The authors' aim in this study was to determine the neuromuscular effects of mivacurium at the laryngeal adductor muscles and the adductor pollicis. METHODS: In 22 adults, anesthesia was induced and maintained with propofol and alfentanil. The force of contraction of the adductor pollicis was recorded, and the laryngeal response was evaluated by measuring the pressure change in the cuff of a tracheal tube positioned between the vocal cords after train-of-four stimulation. Mivacurium (0.07 mg.kg-1 or 0.14 mg.kg-1) was given intravenously (10s). RESULTS: With 0.07 mg.kg-1 mivacurium, onset time was 151 +/- 40 s(mean +/- SD) at the larynx and 241 +/- 79 s at the adductor pollicis, respectively (P < 0.005). Maximum block was 78 +/- 18% and 95 +/- 8%, respectively (P < 0.002), and time to 90% recovery was 11.1 +/- 2.9 min and 23.3 +/- 7.6 min, respectively (P < 0.001). With 0.14 mg.kg-1 mivacurium, onset time also was more rapid at the vocal cords (137 +/- 20 s) than at the adductor pollicis (201 +/- 59 s, P < 0.01). Maximum block was 90 +/- 7% and 99 +/- 1% (P < 0.005), and time to 90% recovery was 16.4 +/- 4.9 min and 27.4 +/- 7.8 min, respectively (P < 0.01). CONCLUSIONS: With mivacurium, onset and recovery are faster at the laryngeal muscles, but block is less intense than at the adductor pollicis. A dose greater than 0.14 mg.kg-1 mivacurium is necessary to ensure complete relaxation at the vocal cords.

Adult↗
PubMed1995

Pharmacokinetics and pharmacodynamics of rocuronium at the vocal cords and the adductor pollicis in humans.

The pharmacokinetic-pharmacodynamic relationship of rocuronium at the laryngeal adductor muscles and the adductor pollicis was determined in eight patients during general anesthesia. Rocuronium was administered as an infusion at a rate of 100 micrograms.kg-1.min-1 over 5 minutes. The half-life of transport between plasma and biophase (effect compartment) was significantly shorter at the adductor laryngeal muscles (2.7 +/- 0.6 minutes, mean +/- SD) than at the adductor pollicis (4.4 +/- 1.5 minutes, p = 0.003). The concentration in the effect compartment producing 50% of the maximum effect was significantly greater at the adductor laryngeal muscles (1424 +/- 148 micrograms.L-1) than at the adductor pollicis (823 +/- 157 micrograms.L-1, p = 0.0001). The shorter onset of neuromuscular blockade at the laryngeal muscles than at the adductor pollicis may be explained by a faster transfer rate at the laryngeal adductor muscles neuromuscular junction than at the adductor pollicis neuromuscular junction.

Adult↗
PubMed1995

Monitoring the onset of neuromuscular block at the orbicularis oculi can predict good intubating conditions during atracurium-induced neuromuscular block.

This study was designed to assess whether monitoring the orbicularis oculi (OO) can predict good tracheal intubating conditions. Fifty patients, ASA grade I or II were studied. Anesthesia was induced with thiopental (5 mg/kg) and fentanyl (3 micrograms/kg). The ulnar and facial nerves were simultaneously stimulated using train-of-four (TOF) stimulations every 10 s. The responses of the adductor pollicis (AP) and the OO were estimated visually. Patients were randomly allocated to receive either atracurium 0.5 mg/kg (n = 30) or 0.3 mg/kg (n = 20). In each group, endotracheal intubation was performed randomly when the OO or the AP was completely blocked. If complete block was not obtained, intubation was performed 300 s after administration of atracurium. Intubating conditions were scored on a 1 to 4 scale. All intubations were performed by the same physician unaware of the dose and the muscular responses. After 0.5 mg/kg, both muscles were completely blocked in all patients. The average onset time (time from the injection of atracurium to the disappearance of all muscular responses after TOF) was shorter at the OO (2.35 +/- 0.12 min) than at the AP (3.59 +/- 0.15 min) (P < 0.001) (mean +/- SD). Endotracheal intubating conditions were comparable in both groups: good or excellent after 0.5 mg/kg. After 0.3 mg/kg, complete block was achieved only 2/20 at the OO and 12/20 at the AP. Intubating conditions were comparable in both groups: poor or inadequate, except in the two patients with complete OO block, for whom conditions were good.(ABSTRACT TRUNCATED AT 250 WORDS)

Atracurium↗
PubMed1994

Neuromuscular effects of vecuronium and neostigmine in Montreal and Paris.

The potency of vecuronium was reported to be greater in Montréal than in Paris. This study was designed to determine whether there were differences in onset, duration, and reversibility with neostigmine between both centres. Twenty ASA I or II adults (ten men, ten women), aged 18-65 yr were studied in each of the two cities, during a standard thiopentone-fentanyl-nitrous oxide (60-70%) - isoflurane 0.5% end-tidal anaesthetic. Train-of-four stimulation was applied every 20 sec to the ulnar nerve at the wrist and the force of contraction of the adductor pollicis muscle was measured. Vecuronium, 0.1 mg.kg-1, was given as a bolus, and neostigmine, 0.04 mg.kg-1, was administered, with atropine 0.02 mg.kg-1, at 25% first twitch height recovery. Onset time to maximum blockade was (mean +/- SD) 3.9 +/- 1.3 min in Paris vs 4.5 +/- 1.3 min in Montréal (NS). Duration from injection to 25% first twitch recovery was shorter (28.5 +/- 6.8 min) in Paris than in Montréal (39.1 +/- 7.3 min) (P < 0.0001). Time from injection of neostigmine to a train-of-four ratio of 70% was not different in Paris (6.3 +/- 2.2 min) from Montréal (5.6 +/- 1.9 min). It is concluded that the duration of an "intubating" dose of vecuronium is longer in Montréal, but, when given at 25% first twitch recovery, neostigmine has the same efficacy in Montréal as in Paris.

Adolescent↗
PubMed1994

Comparison of twitch depression of the adductor pollicis and the respiratory muscles. Pharmacodynamic modeling without plasma concentrations.

BACKGROUND: Although the respiratory muscles (the diaphragm and the laryngeal adductors) recover from paralysis more rapidly than does the adductor pollicis, patients can develop complete paralysis of the respiratory muscles, but not of the adductor pollicis, after bolus administration of vecuronium. The authors used a pharmacodynamic model not requiring muscle relaxant plasma concentrations to reconcile these findings. METHODS: The pharmacodynamic model is based on the traditional model, in which: (1) vecuronium concentration at the neuromuscular junction (C(effect)) is a function of the plasma concentration versus time curve and a rate constant for equilibration between plasma and the neuromuscular junction (k(eo)); and (2) effect is a function of C(effect), the steady-state plasma concentration that produces 50% effect (C50), and a factor to explain the sigmoid relationship between concentration and effect. In the absence of vecuronium plasma concentrations, an empiric model (rather than the usual effect compartment model) can be used to mimic the time delay (proportional, but not identical, to 1/k(eo)) between dose and effect. The model can be used to estimate the steady-state infusion rate that produces 50% effect (IR50), equal to the product of C50 and vecuronium plasma clearance; IR50 for different muscle groups then can be compared to assess relative sensitivity. The authors applied this model to published effect data for subjects given 40-70 micrograms/kg vecuronium in whom paralysis of three muscle groups was measured during opioid/propofol anesthesia. RESULTS: For IR50, the ratio of values for the larynx:diaphragm:adductor pollicis was 1.4:1.2:1; for the equilibration constant (inversely proportional to the time delay), the ratio for the respiratory muscles to the adductor pollicis was 2.5:1. CONCLUSIONS: Vecuronium concentrations peak earlier at the respiratory muscles than at the adductor pollicis, possibly the result of greater perfusion to these organs, leading to earlier onset of paralysis. The observation that bolus injection of vecuronium produces greater paralysis of the respiratory muscles than of the adductor pollicis, despite greater resistance of the respiratory muscles, can be explained by differential rates of equilibration between plasma and various muscles.

Humans↗
PubMed1994

Visual estimation of train-of-four responses at the orbicularis oculi and posttetanic count at the adductor pollicis during intense neuromuscular block.

Posttetanic count (PTC) predicts the time to return of train-of-four (TOF) responses at the adductor pollicis (AP) muscle. The duration of neuromuscular block at the orbicularis oculi (OO) is shorter than at the AP. The aim of this study was to assess whether TOF at the OO can predict, as accurately as PTC does, the time to return of TOF at the AP. Twenty patients, ASA grade I or II, were studied. Anesthesia was induced with propofol, 2-3 mg/kg, intravenously (IV), and fentanyl, 2-3 micrograms/kg IV, and maintained with a propofol infusion. Ulnar and facial nerves were stimulated simultaneously with TOF every 20 s. PTC at the AP was repeated every 5 min. The number of twitches after PTC was estimated by feeling the responses at the thumb. TOF responses at the OO were monitored visually. TOF responses at the AP were recorded using a force transducer. Patients were assigned randomly to receive either atracurium, 0.5 mg/kg (n = 10), or pancuronium, 0.1 mg/kg (n = 10). Times from injection to the first response to PTC (PTC1), to the reappearance of the first response of TOF at the OO (T1OO), and to the reappearance of the first response of TOF at the AP (T1AP) were recorded. After pancuronium and atracurium, PTC1 and T1OO recovered before T1AP (P < 0.001). In all patients, PTC1 recovered earlier than T1OO (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Intravenous↗
PubMed1994

Pharmacokinetics of rocuronium bromide in paediatric patients.

Rocuronium 0.8 mg kg-1 was given to 22 children between the ages of 3 months and 8 years during anaesthesia with N2O/O2, 60:40, and halothane. Blood samples were collected for 360 min for determination of rocuronium concentrations. The pharmacokinetics were best described by a two-compartment model. Two models were fitted, one proportional to weight and the other adjusted for age. Using the first model, volumes and clearances were all proportional to weight: in the second model, only the volume of the second compartment and clearance from the central compartment were proportional to age. The results do not support the use of body surface area, rather than weight for the calculation of paediatric doses of rocuronium. In this study, the volume of the central compartment was larger than the figure obtained in an adult population.

Androstanols↗
PubMed1993

Respiratory mechanics in anaesthetised patients after neostigmine-atropine. A comparison between patients with and without chronic obstructive pulmonary disease.

The aim of this study was to compare the effects of pharmacological reversal of neuromuscular blockade on static compliance and resistance in patients with and without chronic obstructive pulmonary disease (COPD). Twenty patients were studied: 12 patients were free of respiratory disease (NCOPD) and had normal pulmonary function tests. Eight subjects (COPD) had a clinical history of chronic bronchitis and a FEV1 < 70% of the predicted value. All patients were anaesthetised with a continuous infusion of methohexitone and alfentanil. Airway pressure (Paw) was recorded continuously. Static compliance (Crs) was calculated from the relationship between 21 syringe volume (250 ml step) and Paw. Total respiratory resistance (Rrs) was measured at two levels of inspiratory flow and tidal volume. These measurements were made before vecuronium (control), after injection of vecuronium to abolish the first neuromuscular response to train of four, 5 and 15 min after administration of neostigmine 40 micrograms.kg-1 and atropine 10 micrograms.kg-1. In COPD patients Crs and Rrs were significantly greater (1450 +/- 580 ml.kPa-1 and 1.06 +/- 0.68 kPa.l-1.s-1) than in normal patients (1000 +/- 380 ml.kPa-1 and 0.58 +/- 0.22 kPa.l-1.s-1) (P < 0.01). In both groups Crs and end-expiratory pulmonary volume were similar before injection of vecuronium and after neostigmine-atropine administration. In both groups, Rrs was not altered significantly by neostigmine-atropine for the two inspiratory flows. These results suggest that neostigmine-atropine mixture is associated with small changes in respiratory mechanics, and the changes are similar in COPD compared with normal patients.

Airway Resistance↗