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Biomedical subjects

L H Booij

Publications and source records attributed to L H Booij.

At least 19 recordsLinked to original sources

Evaluation of the electroencephalographic bispectral index during fentanyl-midazolam anaesthesia for cardiac surgery. Does it predict haemodynamic responses during endotracheal intubation and sternotomy?

The bispectral index, a value derived from the electroencephalogram, has been proposed as a measure of anaesthetic effect. The aim of the present study was to evaluate the bispectral index during midazolam-fentanyl anaesthesia for cardiac surgery for its possible role as a predictor of increases in systolic blood pressure during endotracheal intubation and sternotomy. After institutional approval 15 consenting patients, scheduled for elective cardiac surgery, were selected for the study. Anaesthesia was induced in all patients with a loading dose of fentanyl 7.5-10 micrograms kg-1, midazolam 0.15 mg kg-1 and pancuronium 0.1 mg kg-1. After a further bolus dose of fentanyl 10-12.5 micrograms kg-1 prior to the start of incision and sternotomy, maintenance infusion rates of fentanyl 4-6 micrograms kg-1 h-1 and midazolam 0.1 mg kg-1 h-1 were started and continued through surgery at the discretion of the anaesthetist and guided by the presenting clinical and haemodynamic responses. The control of anaesthesia was never based on the value of the bispectral index. The mean bispectral index value decreased from 95.7 (3.1) at base-line to 59.5 (12.0) after induction of anaesthesia and then remained below 70 throughout surgery. However, there was an important interindividual variability in bispectral index values despite standardized dosages of fentanyl and midazolam. There was no significant correlation between the bispectral index values in the pre-intubation and pre-incision period and the changes in systolic blood pressure during endotracheal intubation and sternotomy, respectively. In conclusion, the large intersubject variability in the bispectral index values should be investigated further in the light of the great variability in the clinical effects of midazolam and fentanyl. The lack of significant correlation between the bispectral index values and the haemodynamic responses suggest that the bispectral index, which is a helpful monitor of anaesthetic depth, is not a very reliable monitor of global anaesthetic adequacy during total intravenous anaesthesia with a combination of midazolam and fentanyl in cardiac surgical patients.

Adjuvants, Anesthesia↗

Similar motor block effects with different disposition kinetics between lidocaine and (+ or -) articaine in patients undergoing axillary brachial plexus block during day case surgery.

AIM: The aim of this investigation was to compare the clinical effects and pharmacokinetics of lidocaine and articaine in two groups of 15 patients undergoing axillary brachial plexus anesthesia. METHOD: The study had a randomized design. Thirty patients were allocated to one of the two groups. Each patient received either lidocaine (600 mg = 2.561 mMol + 5 microg/ml adrenaline) or articaine (600 mg = 2.113 mMol + 5 microg/ml adrenaline), injected via the axilla of the brachial plexus over a period of 30 seconds. Onset of surgical analgesia was defined as the period from the end of the injection of the local anesthetic to the loss of pinprick sensation in the distribution of all three nerves. RESULTS: The mean onset time of sensory block of the median nerve of both lidocaine and articaine were approximately 10 min. Lidocaine is biexponentially eliminated with a t1/2alpha of 9.95 +/- 14.3 min and a t1/2beta of 2.86 +/- 1.55 h. Lidocaine is metabolized into MEGX (mono-ethyl-glycyl-xilidide) (t(max) 2.31 +/- 0.84 h; C(max) 0.32 +/- 0.13 mg/l; t1/2beta 2.36 +/- 2.35 h). Lidocaine total body clearance was 67.9 +/- 28.9 l/h. Articaine is rapidly and monoexponentially eliminated with a t1/2beta of 0.95 +/- 0.39 h. The total body clearance of articaine is higher than that of lidocaine, 1,133 +/- 582 l/h vs 67.9 +/- 28.9 l/h, respectively (p < 0.0001). The volume of distribution (V(d)), of articaine is a factor 16 higher times than that of lidocaine (p < 0.0001). CONCLUSION: For the axillary administration, lidocaine and articaine show similar pharmacodynamics with a different pharmacokinetic behavior and can therefore be used to the clinical preference for this regional anesthetic technique.

Ambulatory Surgical Procedures↗

Comparison of the effects and disposition kinetics of articaine and lidocaine in 20 patients undergoing intravenous regional anaesthesia during day case surgery.

The aim of this investigation was to assess the effects and disposition kinetics of the local anaesthetic drugs (+/-) articaine and lidocaine during intravenous regional anaesthesia (IVRA). The mean onset time of surgical analgesia of articaine was 2.5 +/- 1.1 min and that of lidocaine 11.2 +/- 5.1 min (p = 0.0006). None of the patients exhibited objective symptoms of toxicity, either local or systemic, during injection of articaine or lidocaine, nor were there any subjective complaints. No changes in blood pressure, heart rate or oxygen saturation were observed with these local anesthetics at any time during the procedure, nor after deflation of the tourniquet. After releasing the tourniquet, articaine appears in the blood and is rapidly eliminated with a t1/2 alpha of 5 +/- 3 min and a t1/2 beta of 59 +/- 39 min due to hydrolysis. Lidocaine is rapidly and biexponentially eliminated with similar half-lives of t1/2 alpha of 4 +/- 2 min and a t1/2 beta of 79 +/- 31 min. Total body clearance of articaine (8.9 +/- 3.5 L/min) is ten times greater than that of lidocaine (0.9 +/- 0.4 L/min; p = 0.0005). We concluded that both (+/-) articaine and lidocaine are suitable and safe agents for IVRA with rapid onset of good surgical anaesthesia. Articaine is a racemic mixture, which is nowadays considered as less favourable. After releasing the tourniquet, articaine is eliminated with a t1/2 beta of 60 min and lidocaine with a t1/2 beta of 80 min. Quicker onset and shorter elimination time favours (+/-) articaine over lidocaine for IVRA in day case settings so that patients treated with articaine will be 'drug free' more quickly than those who receive lidocaine. Faster elimination and more rapid onset are important advantages for articaine in IVRA for day-case procedures.

Adult↗

Disposition of lignocaine for intravenous regional anaesthesia during day-case surgery.

Lignocaine is a suitable and safe agent for intravenous regional anaesthesia (IVRA) with rapid onset of good surgical anaesthesia. The onset time of the local anaesthetic action of lignocaine was 11.2 +/- 5.1 min. Satisfactory surgical conditions, evidenced by good sensory blockade were achieved within 20 min, and no additional analgesics were required. There was no trend towards a fixed sequence, radial, median and ulnar in the development of sensory blockade. No patient exhibited objective symptoms of toxicity, either local or systemic, after release of the tourniquet, nor were there any subjective complaints. No changes in blood pressure, heart rate or oxygen saturation were observed at any time during the procedure, or after deflation of the tourniquet. After releasing the tourniquet lignocaine is rapidly and biexponentially eliminated, with a t1/2a of 4.3 +/- 2.1 min and a t1/2 beta of 79.1 +/- 31.2 min. Total body clearance was 0.86 +/- 0.39 L min-1. Eight patients showed rapid release of lignocaine from the exsanguinated area. In two patients the systemic plasma concentration of lignocaine increased more slowly than in the remaining eight. This can be explained by a greater degree of lignocaine absorbtion in the tissues of the arm. Pharmacokinetic constants after rapid and slow absorption were calculated.

Adult↗

Neuromuscular blocking and cardiovascular effects of Org 9487, a new short-acting aminosteroidal blocking agent, in anaesthetized animals and in isolated muscle preparations.

This study was undertaken to investigate the neuromuscular blocking profile and cardiovascular effects of Org 9487, a new aminosteroidal, non-depolarizing, neuromuscular blocking agent structurally related to vecuronium, in anaesthetized animals and in isolated muscle preparations. In in vitro functional assays of neuromuscular blocking activity, Org 9487 was between eight and 15 times less potent than vecuronium. In cats and monkeys the potency of Org 9487 was approximately one-seventh and one-twentieth, respectively, that of vecuronium. In both species, Org 9487 induced rapidly developing (onset times between 1.5 min and 1.9 min) neuromuscular paralysis, which was shorter-lasting than that of vecuronium and similar in time course to suxamethonium. The vagal: neuromuscular blocking dose ratio for Org 9487 was 3 and ganglion block was seen only at approximately 20 times the neuromuscular blocking dose. There was no evidence in the rat that Org 9487, administered at doses up to 3 mg kg-1, inhibited noradrenaline re-uptake. In anaesthetized dogs, Org 9487 (3 x 90% blocking dose) induced only relatively small and transient haemodynamic effects. The administration of clinically relevant doses of neostigmine or pyridostigmine shortened the time-course profile of Org 9487, even when administered during profound neuromuscular block. In animals, Org 9487 is a low potency, nondepolarizing neuromuscular blocking agent with a time course profile similar to that of suxamethonium. Although Org 9487 is less selective than vecuronium for the neuromuscular junction, it is unlikely to produce prohibitive cardiovascular side effects in man.

Adrenergic alpha-Agonists↗

Accelerated recovery and disposition from rocuronium in an end-stage renal failure patient on chronic anticonvulsant therapy with sodium valproate and primidone.

An end-stage renal failure patient, receiving chronic treatment with the anticonvulsants, sodium valproate and primidone, showed accelerated recovery with enhanced elimination (T1/2(z) = 52 min) and clearance (Cl = 14.4 ml min-1 kg-1) of rocuronium. The pharmacokinetic and pharmacodynamic effects of rocuronium in this patient are compared with those published for healthy and renal failure patients. Increased hepatic binding of rocuronium rather than metabolism is suggested as the possible cause of this effect.

Adult↗

[Malignant hyperthermia as a complication of anesthesia: predisposition is hereditary].

The frequency of malignant hyperthermia in the Netherlands is about 1 in 200,000 anaesthesias. Five times a year, an anaesthetic procedure will be complicated by a malignant hyperthermic metabolic disturbance, which can cause death if treatment is not instituted rapidly, by the administration of dantrolene. Suxamethonium and all the anaesthetic vapours can trigger such a reaction. Malignant hyperthermia patients are healthy patients who have a mutation of the ryanodine receptor gene RYR. Predisposition to malignant hyperthermia is inherited as an autosomal dominant condition. So far a genetic malignant hyperthermia test is not available because of genetic heterogeneity. The in-vitro contracture test in skeletal muscle is currently used as a diagnostic test for malignant hyperthermia. Patients who are likely to be at risk based on a clinical grading score, and family members with at least a 25% chance of inheriting malignant hyperthermia, are eligible for this test.

Calcium Channels↗

Neuromuscular transmission and its pharmacological blockade. Part 2: Pharmacology of neuromuscular blocking agents.

Clinically, neuromuscular blockade is induced with either depolarizing or non-depolarizing relaxants. Suxamethonium is the only depolarizing relaxant still in use. It is hydrolysed in the plasma by pseudo-cholinesterase (plasma cholinesterase). In some patients and in particular diseases the plasma cholinesterase activity is low and hence the effect of suxamethonium prolonged. Suxamethonium is characterized by side-effects such as myalgia, fasciculations and increase in intraocular, intracranial and intragastric pressure. More serious adverse reactions are masseter muscle spasm and potassium release, in patients with some neuromuscular diseases and increase in extrajunctional acetylcholine receptors. As non-depolarizing muscle relaxants benzylisoquinolines and steroidal compounds are mainly used. Each relaxant has its own pharmacological characteristics. The effect of most relaxants depends on liver and renal function because the pharmacokinetic behaviour is strongly dependent on these organs. Also, acid base balance disturbances, change in temperature, and neurological diseases have an effect on the profile of the relaxants. A number of drugs (anaesthetics, antibiotics, antiepileptics, etc.) have an effect on neuromuscular transmission, and thus interact with the relaxants. Some non-depolarizing relaxants cause histamine release and cardiovascular effects.

Body Temperature↗

Neuromuscular transmission and its pharmacological blockade. Part 3: Continuous infusion of relaxants and reversal and monitoring of relaxation.

Continuous infusion is an attractive method of administration when muscle relaxation is needed for a longer period. The pharmacokinetic behaviour of a drug is an important determining factor for the suitability of relaxants for continuous infusion. At present mainly intermediately long acting relaxants are used for this purpose. At the end of surgery residual curarization may exist and thus anaesthesiologists prefer to be able to reverse the relaxants. The anticholinesterases neostigmine, pyridostigmine, and edrophonium are used clinically for this reason. Their effect is prolonged in patients with renal failure, and also affected during acid-base disturbances. Some other drugs have been used experimentally for the reversal of neuromuscular blockade, but are inadequate. Special problems can arise when reversal of a mivacurium-induced or antibiotic-induced blockade is wanted, or mivacurium was administered. Monitoring neuromuscular transmission is an important feature to determine the effect of relaxant administration or to detect residual curarization. It is based on stimulation of peripheral nerves with either single twitch, train of four, tetanic or double burst stimulation. The evoked response can be quantitated with mechanomyography, electromyography, or accelerography. The response of the various muscles to nerve stimulation varies due to the different characteristics of the muscles. Clinically, the use of the adductor pollicis muscle is advised.

Electromyography↗

Neuromuscular transmission and its pharmacological blockade. Part 1: Neuromuscular transmission and general aspects of its blockade.

Blockade of neuromuscular transmission is an important feature during anaesthesia and intensive care treatment of patients. The neuromuscular junction exists in a prejunctional part where acetylcholine is synthesized, stored and released in quanta via a complicated vesicular system. In this system a number of proteins is involved. Acetylcholine diffuses across the junctional cleft and binds to acetylcholinereceptors at the postjunctional part, and is thereafter metabolized by acetylcholinesterase in the junctional cleft. Binding of acetylcholine to its postjunctional receptor evokes muscle contraction. Normally a large margin of safety exists in the neuromuscular transmission. In various situations, apart from up-and-down regulation of acetylcholine receptors, adjustment of acetylcholine release can occur. Pharmacological interference can interrupt the neuromuscular transmission and causes muscle relaxation. For this reason both depolarizing and non-depolarizing muscle relaxants are clinically used. The characteristics of an ideal clinical muscle relaxant are defined. In the description of the pharmacology of the relaxants the importance of pharmacodynamic and pharmacokinetic parameters are defined. Stereoisomerism plays a role with the relaxants. Toxins and venoms also interfere with neuromuscular transmission, through both pre- and postjunctional mechanisms.

Down-Regulation↗

Neuromuscular transmission and its pharmacological blockade. Part 4: Use of relaxants in paediatric and elderly patients, in obstetrics, and in the intensive care unit.

The pharmacodynamic and pharmacokinetic characteristics of the non-depolarizing muscle relaxants are dependent on age. Thus differences are found between paediatric patients, adults, and elderly patients. Muscle relaxants cross the placenta and thus may cause problems in the fetus. Many of the potential adverse effects of relaxant administration are seen more pronounced in intensive care patients. Prolonged effects and problems in wearing patients from the ventilator are observed when muscle relaxants are used in such patients. Critical illness neuropathy is a syndrome different from relaxant induced neuromyopathy, but may be enhanced by relaxant administration.

Adult↗

Regional metabolism of articaine in 10 patients undergoing intravenous regional anaesthesia during day case surgery.

AIMS: To study the pharmacokinetics of articaine and its metabolite articainic acid, in patients undergoing intravenous regional anaesthesia. METHODS: Ten patients (three male, seven female, ASA class 1-2), scheduled for surgery of the hand or forearm were included in the study. Articaine (40 ml, 0.5% solution (200 mg) was injected over 30 s. In total fifteen arterial blood samples were taken; one before injection and then at 10 min intervals, starting 10 min after completion of injection, until the tourniquet was released; thereafter blood samples were drawn at intervals of 1, 5, 10, 15, 20, 25, 30, 45, 60, 75 and 90 min. The tourniquet was released 30 min after completing the injection. RESULTS: During tourniquet application and regional analgesia of 30 min duration, 55% of articaine was hydrolysed by plasma (20%) and tissue (35%) esterase activity to the metabolite articainic acid. After releasing the tourniquet, articaine and its metabolite appeared in the blood; articaine was rapidly eliminated with a t1/2z of approximately 60 min. The plasma concentration of the metabolite articainic acid was the sum of the amount formed during IVRA (55%) and the amount formed after tourniquet release (45%). CONCLUSIONS: Articaine is a safe agent for intravenous regional anaesthesia (IVRA) with rapid onset of good surgical anaesthesia. During tourniquet application and regional analgesia, 55% of the administered dose is already hydrolysed, thus reducing the chance of side effects after tourniquet release.

Anesthesia, Intravenous↗

Repeated enflurane anaesthetics and model predictions: a study of the variability in the predictive performance measures.

We quantified the total variability (reproducibility) and the within-patient but between repeat anaesthetics variability (repeatability) in measures which are used to judge the predictive performance of our physiological model. We studied 14 patients who received enflurane closed-circuit anaesthesia on two occasions. The end-tidal concentrations measured and those predicted served to calculate the predictive performance measures of the model: root mean squared error (rmse = total error), bias (systematic error) and scatter (error around the bias). The overall results were: rmse 15 (7)%, bias 0 (14)% and scatter 9 (3)% (grand mean (total SD)). The within-patient SD values were smaller for the rmse (4%) and bias (10%), but not for scatter (3%). The repeat rmse values and biases were linked to the first results. This implies that these performance measures depended partly on the patient. As there was no association between the personal performance measures and age, sex, body weight, body surface area or body mass index, these characteristics cannot be used to further tune the model.

Adolescent↗

Comparison of the disposition kinetics of lidocaine and (+/-)prilocaine in 20 patients undergoing intravenous regional anaesthesia during day case surgery.

OBJECTIVE: The aim of this investigation was to compare the pharmacokinetics of lidocaine and prilocaine in two groups of 10 patients undergoing intravenous regional anaesthesia. METHOD: The study had a randomized design. The patients were allocated to one of the two groups of 10. Each group received either lidocaine (200 mg = 0.855 mM) or prilocaine (Citanest, 200 mg = 0.909 mM), injected intravenously over a period of 30 s. Onset of the surgical analgesia was defined as the period from the end of the injection of the local anaesthetic to the loss of pinprick sensation in the distribution of all three nerves. RESULTS: The mean onset time of surgical analgesia of lidocaine was 11.2 +/- 5.1 min and that of prilocaine was 10.9 +/- 6.0 min. After releasing the tourniquet, lidocaine is bi-exponentially eliminated with a t1/2 alpha of 4.3 +/- 2.1 min and a t1/2 beta of 79.1 +/- 31.2 min. Total body clearance was 0.86 +/- 0.39 litres/min. Prilocaine is rapidly and bi-exponentially eliminated with a t1/2 alpha of 3.0 +/- 1.6 min and a t1/2 beta of 29.9 +/- 15.7 min. The total body clearance of prilocaine is higher than that of lidocaine, 4.15 +/- 1.31 vs. 0.86 +/- 0.39 litres/min, respectively (P = 0.0007). Both compounds show comparable volumes of distribution (Vd, Vss and V beta) and a comparable t1/2 alpha (4.3 +/- 2.1 vs. 3.0 +/- 1.6 min; P = 0.1780). The t1/2 beta for the two compounds were different (P = 0031); 79.1 +/- 31.2 min for lidocaine and 29.9 +/- 15.7 min for prilocaine. The mean residence time (MRT) of lidocaine (193 +/- 233 min) also differed significantly from that of prilocaine (33.4 +/- 19.9 min; P = 0.0022). CONCLUSION: Lidocaine is preferred for relatively long procedures and prilocaine for short procedures.

Adult↗

Epidural metabolism of articaine to its metabolite articainic acid in five patients after epidural administration of 600 mg articaine.

The clinical pharmacokinetics, metabolism and renal excretion of articaine and its metabolite articainic acid have been investigated in man after epidural administration. (+/-)-Articaine and its metabolite (+/-)-articainic acid have different pharmacokinetic constants (P = 0.0079) except for lag-time (tlag; 0.06 min), first phase distribution of elimination (t 1/2 alpha; 0.49 +/- 0.21 h), and elimination half life (t 1/2 beta; 2.19 +/- 0.98 h), which are all the same for both compounds. The total body clearance of articaine (103 +/- 57 L h-1) is 10 times higher than that of the metabolite articainic acid (10.7 +/- 1.80 L h-1, P = 0.0079). With similar half-life (t 1/2 beta) values (2h), the volumes of distribution (V beta) are 10 times higher for the parent drug than for the metabolite ((329 +/- 212 L compared with 38.4 +/- 7.5 L, respectively; P = 0.0079). The difference between the areas under the curves for total plasma articainic acid and that formed in the plasma gives an indication of the percentage metabolism during epidural transfer (5.38 +/- 1.51%). This percentage of metabolism corresponds to a mean epidural transfer time of 5 min. The main compound in the urine is articainic acid (64.2 +/- 14.4%), followed by articainic acid glucuronide (13.4 +/- 4.97%) and the parent drug (1.45 +/- 0.77%). In total, 79.0 +/- 18.5% of the dose is recovered in the urine. The renal clearance of articaine is 22.5 +/- 13.9 mL min-1, whereas that of articainic acid is 119.6 +/- 30.1 mL min-1 (P < 0.0001). The apparent renal clearance of articainic acid glucuronide was 25.4 +/- 12.0 mL min-1. This value does not differ from that of the parent drug (P > 0.8). Articainic acid glucuronide is not present in plasma, but has an apparent renal clearance of 25 mL min-1. These results suggest that articainic acid is glucuronidated by the tubular cells and then excreted.

Adult↗