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Biomedical subjects

J F Crul

Publications and source records attributed to J F Crul.

At least 19 recordsLinked to original sources

A scoring system for basic cardiac life support skills in training situations.

A valid and reproducible system for determining basic cardiac life support (BCLS) skills can help to evaluate the effect of instruction courses and to estimate the results of educational activities. The aim of this study was to develop and test such a system in accordance with the Standards and Guidelines of the American Heart Association (AHA). Five criteria were defined in advance towards such a system (1) Inadequate techniques must be reflected by a fail score. (2) Skilled persons should achieve a pass score. (3) The effect of training must be reflected by an improvement of the score. (4) Inter- and intra-observer variability must be negligible. (5) The system should be simple to apply. The system was developed, and in order to test the system, the BCLS skills of 40 ambulance nurses were tested once and those of 148 lay people twice. All cardiopulmonary resuscitation (CPR) attempts were performed on a mannequin. The relevant parameters of the attempt were continuously recorded and printed. Penalty points were assigned in a predefined way for aberrations of the techniques advised in the Standards and Guidelines. The system satisfied the five criteria mentioned above. It therefore offers a reliable and reproducible evaluation of BCLS skills.

Allied Health Personnel

The effects of a 16-N-homopiperidino analogue of vecuronium on neuromuscular transmission in anaesthetized cats, pigs, dogs and monkeys, and in isolated preparations.

Org 9991, a 16-N-homopiperidinium substituted vecuronium analogue, has been tested for neuromuscular blocking activity in anaesthetized cats, pigs, dogs and monkeys, and in isolated nerve-muscle preparations. Org 9991 exhibited non-depolarizing neuromuscular blocking activity of the competitive type, being reversible by neostigmine and showing no endplate channel blocking action in isolated preparations. In cats, 50% vagal block was observed at doses of Org 9991 approximately 10 times those producing 50% neuromuscular block; no ganglion block was seen at these doses. Effects on blood pressure or heart rate at 90% twitch blocking doses were either minor or absent. The potency and time course of action of Org 9991 remained similar in all four species: i.e. 90% block at ca 200-300 micrograms kg-1; onset time ca 1.2-1.9 min; duration 90% ca 4.5-8.9 min. This study suggests that 16-N-homopiperidinium analogues of vecuronium may provide leads in the quest for a potent non-depolarizing replacement for suxamethonium.

Androstanols

Cardiopulmonary resuscitation on the general ward: no category of patients should be excluded in advance.

In this study 91 consecutive CPR cases in 90 patients on general wards were evaluated during 18 months. Fifteen patients (16.5%) could be discharged, which is relatively favourable in comparison to the literature. Children proved to have a better chance to leave the hospital alive than adults (6/18 vs. 9/72; P less than 0.05). No factors with negative predictive value before the cardiopulmonary arrest could be isolated. Even oncological patients, often described as a prognostically poor category, with a success rate of 27% (6/22) did not differ from other categories. Patients with isolated respiratory arrest, ventricular tachycardia or ventricular fibrillation at the arrival of the CPR-team had a better chance to be discharged from the hospital. A rapid decrease in survival was noted if a CPR attempt lasted longer than 10 min (P less than 0.001). When there is no return of vital signs within 30 min the CPR attempt can be stopped. During follow-up period (mean 6 month) 2 of the 15 survivors (13.3%) died from a non-cardiopulmonary cause. It is concluded that no category of patients can be excluded from CPR in advance. Although ultimate success rate for CPR in the general wards will rarely exceed 15%, CPR has to be initiated in most cases of cardiopulmonary arrest.

Adolescent

The efficacy and safety of nalbuphine (NUBAIN) in balanced anesthesia. A double blind comparison with fentanyl in gynecological and urological surgery.

In a prospective double blind study the efficacy and safety of nalbuphine as an analgesic in balanced anesthesia has been compared to fentanyl. In 63 patients, ASA class I-III, major gynecological or urological surgical procedures were performed under balanced anesthesia. Analgesia could be satisfactory maintained in all cases, but in cases of nalbuphine more hypnotics were necessary to keep the patients unconscious. The ratio of fentanyl and nalbuphine consumption was 1:200 (by weight). The nalbuphine cases can be distinguished by: more stable but higher arterial pressures and absence of arrythmia; lower incidence of nausea and vomiting in the postoperative period; less respiratory depression at the end of anesthesia, not needing antagonists, as compared to 11 patients needing antagonization in the fentanyl group; and a larger incidence of minor local allergic reactions at the injection site. Awareness was not observed in any patient of either group. Although nalbuphine has a weaker analgesic and hypnotic effect, it is perfectly possible to provide balanced anesthesia in combination with a hypnotic and a muscle relaxant. Advantages are the absence of respiratory depression as well as nausea and vomiting in the postoperative period.

Adolescent

Pulse oximetry in the recovery room.

Haemoglobin oxygen saturation (SO2) was measured percutaneously with a pulse oximeter, in a group of 150 healthy ambulant volunteers to determine the range of normal values. The measuring site was not arterialised in advance. SO2 was below 94% in 13.3% of cases, while in no case was it below 90%. SO2 was then measured in 350 patients in the recovery room after a variety of surgical and anaesthetic procedures. Only 1.1% of patients who received additional oxygen following general anaesthesia exhibited an SO2 below 90%, compared to 16.7% of similar cases who did not receive additional oxygen. Administration of additional oxygen raised the SO2 above 90% in all the latter cases. In only 55.3% of those who did not receive additional oxygen was the SO2 above 94%, compared to 86.7% of normal volunteers and 73.9% of patients who received additional oxygen. This study reiterates the need to administer supplemental oxygen to all patients in the recovery room, unless facilities are available to measure SO2. A lower alarm limit of 90% is appropriate for the peri-operative period when using the Criticare Systems 501 oximeter.

Adolescent

4-Aminopyridine potentiates neostigmine and pyridostigmine in man.

To elucidate the interaction of 4-aminopyridine with neostigmine and pyridostigmine, the authors studied 57 anesthetized surgical patients using a technique of constant infusion of pancuronium to quantitate antagonist activity. 4-Aminopyridine, 0.15 or 0.35 mg/kg, produced no antagonism, while 0.5 mg/kg produced a mean 24 +/- 6 per cent (peak) antagonism. The dose that produced 50 per cent antagonism (ED50) of neostigmine alone was 22 micrograms/kg; with 0.35 mg/kg 4-aminopyridine, it was 7 micrograms/kg. The ED50 of pyridostigmine alone was 110 micrograms/kg; with 0.35 mg/kg 4-aminopyridine, it was 27 micrograms/kg. 4-Aminopyridine prolonged the onset times of both neostigmine and pyridostigmine, but prolonged the duration of action of neostigmine only. At a given level of antagonism of pancuronium, adding 4-aminopyridine 0.35 mg/kg, to neostigmine and to pyridostigmine decreased the amounts of atropine needed to prevent a change in heart rate by 68 and 70 per cent, respectively. The authors conclude that 4-aminopyridine potentiates antagonism of a pancuronium-induced neuromuscular blockade by neostigmine or pyridostigmine. Also, less atropine is needed to prevent cardiac muscarinic stimulation when 4-aminopyridine is used with either neostigmine or pyridostigmine.

Adult

Effect of different anesthetics on the pharmacokinetics and pharmacodynamics of pancuronium in the cat.

To investigate the effect of different anesthetics on the pharmacokinetics and pharmacodynamics of pancuronium, 120 microgram/kg i.v., cats were anesthetized with either pentobarbital (N = 4), ketamine (N = 4), enflurane (N = 5), or halothane (N = 5). A longer onset time and duration of neuromuscular blockade occurred during enflurane and halothane anesthesia. The apparent elimination half-life was longer and the total voluem of distribution at steady state larger during halothane anesthesia. The plasma concentration of pancuronium required for neuromuscular blockades was less during enflurane than during the other three anesthetics. We conclude that inhalation anesthetics may prolong a neuromuscular blockade by altering both the pharmacokinetics and pharmacodynamics of pancuronium.

Adjuvants, Anesthesia

Effect of tetrahydroaminoacridine and 4-aminopyridine on recovery from ketamine-diazepam anesthesia in the macacus rhesus monkey.

Tetrahydroaminoacridine (T.H.A., Tacrine) 1 mg/kg, and 4-aminopyridine (Pymadin) 0.2 and 1.0 mg/kg i.v., significantly reduced the recovery time when the were administered after ketamine-diazepam anesthesia in Maccacus Rhesus monkeys. Anesthesia was induced with ketamine (50 mg), diazepam (1.2 mg) and sodium glycopyrrolate (0.02 mg) as a secretiondrying agent, as a single bolus injection. Anesthesia was continued with ketamine by constant infusion of a solution of 5 mg/ml, at a speed of 20 mg/ml, at a speed of 20 ml/hour, during 30 minutes. The 5 monkeys in the control group were allowed to recover spontaneously. The test series consisted of the same monkeys, with an adequate rest period of one or more weeks between anesthesias. Recovery was indicated by production of nystagmus, and by an awake pattern in the EEG. Clinical signs, restlessness and purposeful movements, were also used.

4-Aminopyridine

The comparative influence of gamma-hydroxy butyric acid, althesin and etomidate on the neuromuscular blocking potency of pancuronium in man.

The potentiating effect of gamma-hydroxy butyric acid (GHB), Althesin and etomidate on pancuronium was studied in man. GHB proved to influence pancuronium the least whereas Althesin and etomidate potentiate considerably. It is concluded that the amount of non-depolarizing relaxant needed depends on the type of anesthesia given. For neuromuscular blocking studies, GHB and/or thiopentone anesthesia seem to be preferable.

Alfaxalone Alfadolone Mixture

Potentiation of neostigmine and pyridostigmine by 4-aminopyridine in the rat.

The interaction between 4-aminopyridine and neostigmine or pyridostigmine was studied in vivo in the rat sciatic nerve-anterior tibialis preparation using the constant infusion of pancuronium technique. The ED50 (dose of drug which produced a 50% antagonism) of neostigmine, pyridostigmine and 4-aminopyridine were 18, 49 and 440 microgram kg(-1) respectively. The addition of 100 microgram kg(-1) of 4-aminopyridine, which produced no antagonism by itself, decreased the neostigmine ED50 to 7.4 microgram kg(-1). The addition of 200 microgram kg(-1) of 4-aminopyridine, which produced a 30% antagonism by itself, decreased the ED50 of pyridostigmine to 11 microgram kg(-1). We conclude that both neostigmine and pyridostigmine interact with 4-aminopyrine synergistically.

Aminopyridines

The role of the recovery room for the safety of anesthesia.

Three groups of activities taking place in the recovery room are separately analyzed and compared with the same done on the wards. It is concluded that all three of them are preferably done in the recovery room. When these principles are followed, mortality in the direct postoperative period can be reduced to an absolute minimum. Data from 50,000 cases confirmed this statement.

Critical Care

Hypothermia and the pharmacokinetics and pharmacodynamics of pancuronium in the cat.

We tested the effect of hypothermia on the pharmacokinetics and pharmacodynamics of pancuronium in the cat. In 14 cats given pancuronium, 120 microgram/kg i.v., we found that neuromuscular block lasted between 2.5 and 3.0 times longer at 29 degrees C (N = 5) than at 34 degrees C (N = 5) or 39 degrees C (N = 4). The apparent plasma elimination half-life was 46 +/- 7 min (S.E.) at 29 degrees C as compared to 21 +/- 2 and 25 +/- 6 min at 34 and 39 degrees C, respectively. The volume of distribution of the central compartment and total volume of distribution at steady state were less at 29 and 34 dgrees C than at 39 degrees C. Total plasma clearance was 4.3 +/- 0.4 ml/kg/min at 29 degrees C and 10.7 +/- 0.9 and 10.9 +/- 1.5 ml/kg/min at 34 and 39 degrees C, respectively. The reduced plasma clearance resulted at least in part from a markedly reduced biliary and urinary excretion of pancuronium at 29 degrees C as compared to 34 and 39 degrees C. In four other cats, the plasma concentration of pancuronium was correlated with depression of twitch tension under steady-state conditions. The ED50 of pancuronium (plasma concentration required for a 50% depression of twitch tension) was 0.035 and 0.073 microgram/ml at 29 and 38 degrees C, respectively. We conclude that a pancuronium neuromuscular block is prolonged at 29 degrees C because of an increased sensitivity of the neuromuscular junction to pancuronium and delayed biliary and urinary excretion.

Animals

The comparative potency and pharmacokinetics of pancuronium and its metabolites in anesthetized man.

To determine the potency of pancuronium and its metabolites, 3-OH-, 17-OH- and 3,17-OH-pancuronium, cumulative dose-response curves were determined in five anesthetized patients with each drug. Pancuronium (ED50 = 0.041 mg/kg) was 2 times more potent than 3-OH-pancuronium (ED50 = 0.082 mg/kg), 50 times more potent than 17-OH-pancuronium (ED50 = 2.0 mg/kg) and 54 times more potent than 3,17-OH--pancuronium (ED50 = 2.15 mg/kg). In 21 other patients, one equipotent dose of either pancuronium or one of its metabolites was given as an i.v. bolus. Onset time and duration of neuromuscular blockade from 3-OH- and 3,17-OH-pancuronium did not differ significantly from that of pancuronium; 17-OH-pancuronium had a shorter duration of action than did pancuronium. Although pancuronium tended to have a slightly longer elimination half-life, the pharmacokinetics of the four drugs did not differ significantly. The elimination half-lifes were 110, 68, 73 and 71 min for pancuronium and its 3-OH, 17-OH and 3,17-OH derivatives, respectively. We conclude that although pancuronium is more potent than its 3-OH, 17-OH and 3,17-OH metabolites, the pharmacokinetics of these three metabolites do not differ from each other and from that of pancuronium.

Dose-Response Relationship, Drug

Relationship of the serum concentration of pancuronium to its neuromuscular activity in man.

The relationship between the time course of the decay of serum concentrations of pancuronium and its neuromuscular blocking effect has been investigated after the intravenous administration of 50, 80 and 100 microgram/kg doses to anesthetized patients. Following administration of these doses, maximal neuromuscular block in the adductor pollicis muscle developed in about 7, 2.5, and 2 minutes and lasted about 20, 40, and 60 minutes, respectively. The times from start of recovery to return of twitch tension to 25, 50, and 75 per cent of control were similar in the different dosage groups, but occurred progressively later with increasing doses. At times of 25, 50, and 75 per cent recovery mean serum concentrations (pooled values) were 0.13 +/- 0.01,0.11 +/- 0.01, and 0.10 +/- 0.01 microgram/ml (+/- SEM), respectively. Neuromuscular transmission to the adductor pollicis muscle started to recover at a mean serum pancuronium concentration of 0.21 +/- 0.03 microgram/ml. The data obtained in this study are in agreement with the experimental and clinical findings of similar studies with d-tubocurarine, and indicate that there is a correlation between the serum concentrations of muscle relaxants and the intensity of their neuromuscular activities.

Adolescent