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Biomedical subjects

J Spierdijk

Publications and source records attributed to J Spierdijk.

At least 37 records · Page 2Linked to original sources
PubMed1988

The efficacy of flumazenil versus physostigmine after midazolam-alfentanil anaesthesia in man.

The effects of flumazenil and physostigmine were studied in adult surgical patients recovering from midazolam-alfentanil anaesthesia. Thirty-two patients were anaesthetized with midazolam (0.2 mg kg-1 and 0.36-0.66 mg kg-1 h-1 by infusion) and alfentanil (0.15 mg kg-1 and 0.03-0.15 mg kg-1 h-1 by infusion), vecuronium, 50% nitrous oxide in oxygen, intubated and ventilated. The midazolam and alfentanil infusions were stopped at the end of surgery. Residual neuromuscular blockade and ventilatory depression were antagonized and the patients were extubated. In the recovery room, patients received either flumazenil 1 mg or physostigmine 2 mg i.v. over 10 min in a randomized, double-blind way. Before and up to 2 h after injection, patients were asked to perform two psychomotor tests. The degree of sedation and orientation in time and space were also determined. Seventeen patients received flumazenil and 15 patients received physostigmine. Before injection all patients were heavily sedated. After flumazenil, patients were fully awake within 6-7 min but sedation recurred 10-20 min later. After physostigmine, the degree of sedation did not change. The difference in the degree of sedation was significant until 30 min after injection. The time-course of test scores and orientation were similar to that of sedation. No serious side-effects or haemodynamic changes were observed after flumazenil. After physostigmine, seven patients had an increase in heart rate to 140 beats min-1 and blood pressure decreased in three patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Antagonism of midazolam sedation by flumazenil: a placebo-controlled study in patients recovering from intravenous anaesthesia with high doses of midazolam.

Twenty adult surgical patients were anaesthetized with high-dose midazolam and alfentanil by infusion, vecuronium, and intubated and ventilated with 50% N2O in O2. The midazolam and alfentanil infusions were stopped at the end of surgery. Residual neuromuscular blockade and ventilatory depression were antagonized and the patients extubated. In the recovery room, patients were randomly allocated to receive either flumazenil 1 mg of placebo i.v. Before, and until 2 h after injection, patients were asked to perform psychomotor tests. In addition, sedation, comprehension and orientation were scored. The flumazenil (n = 10) and the placebo (n = 10) groups were comparable. Prior to injection all patients were heavily sedated. After flumazenil all were awake within 2-3 min, but fell asleep again 15-60 min later. The improvement in test scores was sustained for a longer time. After placebo, patients awoke in 1-2 h. At 60 and 120 min, test scores in the two groups were similar. Heart rate, blood pressure and respiration rate did not change. No side-effects were observed or reported. It is concluded that flumazenil is an effective and safe antagonist of high dose midazolam, with a rapid onset but a short duration of action.

Adult↗
PubMed1987

Plasma concentrations of epidural bupivacaine in mother and newborn: 0.125% versus 0.375%.

Central venous plasma concentrations of bupivacaine were determined in two groups of 15 parturients each who were given epidural analgesia for labor and vaginal delivery. One group received 10 ml of 0.125% bupivacaine plus epinephrine 1:800,000, the other group received 7 ml of 0.375% bupivacaine plus epinephrine 1:800,000. Plasma concentrations of bupivacaine in the umbilical venous (UV) and the umbilical arterial (UA) blood of their babies were also determined. The mean UA, UV, and maternal central venous (MV) plasma concentrations of bupivacaine differed significantly between the two groups: in patients given 0.375% bupivacaine UA values were 63% higher (P less than 0.01), UV values were 57% higher (P less than 0.01), and the MV values were 34% higher (P less than 0.05) than in patients given 0.125% bupivacaine. The measured plasma concentrations speak in favor of the less concentrated solution of bupivacaine in epidural analgesia for obstetrics. Seven milliliters of bupivacaine 0.375% is suitable for epidural analgesia in obstetrics but a low concentration-low dose technique, using 10 ml of bupivacaine 0.125% plus epinephrine 1:800,000 is safer. It provides good analgesia with minimal or no motor block and is associated with low maternal and neonatal plasma concentrations of bupivacaine, well below toxic levels and, to our knowledge, lower than in any other study.

Anesthesia, Epidural↗
PubMed1987

Pharmacokinetics of lignocaine and bupivacaine in surgical patients following epidural administration. Simultaneous investigation of absorption and disposition kinetics using stable isotopes.

The pharmacokinetics of lignocaine (lidocaine) and bupivacaine following epidural administration were studied in 12 surgical patients using a stable isotope method. Shortly after epidural administration of the agent to be evaluated, a deuterium-labelled analogue was administered intravenously. Plasma concentrations of the unlabelled and the deuterium-labelled local anaesthetics were determined using gas chromatography and mass fragmentography. The pharmacokinetic behaviour of both agents was consistent with a 2-compartment open model and two parallel first-order absorption processes. The mean distribution and elimination half-lives were 12 minutes and 100 minutes for lignocaine, and 22 minutes and 143 minutes for bupivacaine. The mean volumes of the central compartment and the mean steady-state volumes of distribution were: lignocaine, 43L and 99L; bupivacaine, 33L and 68L. Total plasma clearances averaged 0.95 L/min (57 L/h) for lignocaine and 0.52 L/min (31.2 L/h) for bupivacaine. The half-lives, characterising the fast and slow absorption processes, were 9.3 and 82 minutes for lignocaine, and 7.0 minutes and 362 minutes for bupivacaine; the fractions of the doses absorbed in the fast and slow processes were lignocaine 0.38 and 0.58, bupivacaine 0.28 and 0.66, respectively. The results indicate that the local anaesthetics are completely absorbed from the epidural space into the general circulation. The initial absorption rates of both local anaesthetics appear to be similar, but, later, the absorption of bupivacaine proceeds much more slowly than the absorption of lignocaine.

Absorption↗
PubMed1987

Epidural anesthesia with bupivacaine: effects of age on neural blockade and pharmacokinetics.

Effects of aging after epidural administration of 0.5% bupivacaine without epinephrine were studied in two groups of patients, between 20 and 55 yr old and older than 55 yr, respectively. All patients received 95 mg bupivacaine HCl. The onset of analgesia in caudad segments decreased with age and the upper level of analgesia increased with age. Effects of age on duration of anesthesia could not be demonstrated. The total plasma clearance of bupivacaine decreased and the terminal half-life increased with age. Age had no effect on the peak plasma concentrations and time to peak concentrations.

Adult↗
PubMed1987

Spinal anesthesia with glucose-free bupivacaine: effects of age on neural blockade and pharmacokinetics.

Effects of age on spinal anesthesia using glucose-free 0.5% bupivacaine without epinephrine were studied in two groups of patients, one between 20 and 55 yr old, the other older than 55 yr. All patients received 15 mg bupivacaine. The time to onset of analgesia in caudad segments and the time to maximal motor blockade decreased with age. The upper level of analgesia did not change significantly with increasing age. The times to recovery from analgesia at T12 and for the total disappearance of analgesia were longer in the older patient group. Effects of age on duration of motor blockade could not be demonstrated. Peak plasma concentrations of bupivacaine were significantly greater and the total plasma clearance significantly decreased in older patients. Age had no effect on time to peak concentration or the terminal half-life.

Adult↗
PubMed1987

Spinal anesthesia with hyperbaric lidocaine and bupivacaine: effects of epinephrine on the plasma concentration profiles.

The effects of epinephrine on the plasma concentration profiles and some derived pharmacokinetic parameters were studied after subarachnoid injection of hyperbaric lidocaine and bupivacaine solutions. Addition of epinephrine to the local anesthetic solution reduced the mean peak plasma concentration of lidocaine from 526 to 376 ng/ml, but did not significantly reduce the mean peak plasma concentration of bupivacaine (70 vs 56 ng/ml). Epinephrine did not affect the times at which the peak concentrations were reached, the terminal half-lives, or the total plasma clearances. The observed effects of epinephrine on the peak plasma concentrations are consistent with the vascular activity of lidocaine and bupivacaine, respectively.

Adult↗
PubMed1986

Epidural anesthesia with lidocaine and bupivacaine: effects of epinephrine on the plasma concentration profiles.

The effects of epinephrine on the plasma concentrations and derived pharmacokinetic parameters were studied after epidural administration of lidocaine and bupivacaine. Addition of epinephrine to the local anesthetic solutions reduced the mean peak plasma concentrations of lidocaine and bupivacaine from 2.2 to 1.7 micrograms/ml (23%) and from 0.73 to 0.53 microgram/ml (28%), respectively, but did not alter the times at which the peak concentrations were reached. Epinephrine also did not alter the terminal half-lives or the total plasma clearances. The results suggest that addition of epinephrine to minimize plasma concentrations is as relevant with bupivacaine as it is with lidocaine.

Adult↗
PubMed1983

Anaesthetic induction with alfentanil: comparison with thiopental, midazolam, and etomidate.

The speed, side effects and cardiovascular changes associated with anaesthetic induction and endotracheal intubation following alfentanil (20 micrograms/kg/min, IV), thiopental (84 micrograms/kg/min, IV), etomidate (5 micrograms/kg/min, IV) and midazolam (20 micrograms/kg/min, IV) prior to halothane-nitrous oxide general anaesthesia were evaluated and compared in 80 patients undergoing elective general surgical operations. Anaesthetic induction was fastest with etomidate and thiopental (approximately one minute) and slowest with midazolam (about two minutes). Systolic arterial blood pressure (SBP) was decreased at the moment of unconsciousness with thiopental but unchanged with the other compounds. Heart rate (HR) was increased at unconsciousness with midazolam and thiopental but unchanged with etomidate and alfentanil. After intubation HR was increased in all groups except those induced with alfentanil. Arrhythmias were infrequent (5 per cent or less in all groups). Rigidity during induction only occurred with alfentanil (55 per cent) and pain on injection only with etomidate (35 per cent) and alfentanil (5 per cent). Postoperative vomiting was infrequent in all groups (15 per cent) except etomidate (55 per cent). No patient remembered any aspect of laryngoscopy or the operation and all rapidly regained consciousness at the end of operation. The results of this study demonstrate that with the exception of rigidity (which is easily overcome with succinylcholine) and a slightly slower onset of action, alfentanil compares favourably as an induction agent with thiopental and is better than midazolam and etomidate. Alfentanil is superior to all three other induction agents with respect to cardiovascular stability during induction and intubation.

Adjuvants, Anesthesia↗
PubMed1983

Plasma concentrations of lidocaine and bupivacaine after subarachnoid administration.

Plasma concentrations were measured after subarachnoid administration of 75 mg lidocaine in a hyperbaric solution and 15 mg bupivacaine in either a hyperbaric or an isobaric solution. Peak concentration times (tmax), peak concentrations (Cmax), apparent elimination half-lives (t1/2el), and areas under the curves (AUC) were determined. The values of tmax, Cmax, t1/2el and AUC were 66 +/- 32 min, 444 +/- 203 ng/ml, 2.0 +/- 0.3 h, and 87.0 +/- 9.8 mg . 1(-1) . min, respectively, for lidocaine. Those obtained after administration of a hyperbaric bupivacaine solution were 54 +/- 11 min, 63 +/- 22 ng/ml, 3.6 +/- 1.4 h, and 19.1 +/- 5.4 mg . 1(-1) . min. Results, obtained with isobaric bupivacaine solutions, were: 86 +/- 24 min, 63 +/- 15 ng/ml, 3.2 +/- 0.4 h, and 18.1 +/- 5.4 mg . 1(-1) . min. The results indicate roughly similar absorption rates from the subarachnoid space into the general circulation after administration of hyperbaric solutions of lidocaine and bupivacaine. Bupivacaine tended to be absorbed slower when it is administered in an isobaric solution.

Adolescent↗
PubMed1982

A central low vacuum pipeline system for the disposal of waste anaesthetic gases.

An independent low vacuum pipeline system for scavenging waste anaesthetic gases is described. The pipeline system has terminal points in several operating and induction rooms. At each terminal point a connection box is installed, eigher in the wall or in a ceiling pendant. Excess gases from the anaesthetic apparatus or the patient ventilator are collected in a reservoir and subsequently sucked through the pipeline system, together with a surplus of air, extracted from the room via openings in the terminal box. The total suction rate is 100 1/min at each terminal box. Once connected, the system needs no looking after by the anaesthetist. Sub-atmospheric and positive pressures, measured at the point of connection to the anaesthetic apparatus are always between -11 Pa and +60 Pa, complying with the current standards.

Anesthesiology↗
PubMed1981

The Leiden scavenging system: A simple and versatile apparatus to control air pollution in operating rooms.

A scavenging system which can be attached to a variety of anaesthetic machines and ventilators is described. Gas venting can occur via a central vacuum system, a suitable injector, fan or pump, through the exhaust duct of an air-conditioning system, or by a passive system. The resistance and back pressures applied to the anaesthetic apparatus are negligible. Leakage tests showed that the collected gases and vapours were substantially removed by the scavenging device.

Air Pollution↗