Biomedical subjects

J W van Kleef

Publications and source records attributed to J W van Kleef.

At least 37 records · Page 2Linked to original sources

PubMed1994

[Postoperative pain control in The Netherlands].

OBJECTIVE: To determine how postoperative analgesia care is managed in the Netherlands. DESIGN: Descriptive study (questionnaire). SETTING: Departments of anaesthesiology in all 168 Dutch hospitals. METHOD: Questionnaires were sent inquiring about postoperative pain therapies and their complications, the organisation and management of postoperative analgesic care, the importance of effective pain control, factors of influence on patient's assessment of pain and the management of the quality of postoperative analgesia. RESULTS: The questionnaires of 73% (n = 122) of the hospitals were suitable for analysis. Locoregional analgesic techniques are used, but intermittent intramuscular administration of an opioid is still the analgesic therapy of choice in the postoperative period. 89% of the interviewed anaesthesiologists assess the average intensity of postoperative pain as moderate or severe, and more than half of the interviewed anaesthesiologists answered that effective postoperative pain management is of substantial influence on the postoperative recovery of the patient. CONCLUSION: It is essential to improve postoperative pain control in the Netherlands. Frequent assessments and precise documentation of the intensity of pain and pain relief, on which further therapy can be based, might be a first step in improving postoperative pain control. Optimal postoperative pain management requires the input of equipment and staff.

Analgesia↗

PubMed1994

Improved clean-up procedure for the high-performance liquid chromatographic assay of bupivacaine enantiomers in human plasma and ultrafiltrate in the nanogram per milliliter range.

A clean-up procedure to obtain a minimal detectable concentration of 5-10 ng bupivacaine enantiomer per milliliter human plasma is described. The procedure consists of precipitation of plasma proteins using acetonitrile, followed by solid-phase extraction using a cyano column. The eluate is then made alkaline, and bupivacaine is extracted using n-hexane. After evaporation of n-hexane, the residue is redissolved in the eluent used for HPLC analysis. The HPLC method has been described previously. The minimal detectable concentrations using this method are ca. 8 and 10 ng/ml for R-(+)- and S-(-)-bupivacaine, respectively. For both enantiomers, r2 is > 0.995 over the range of 9.5-760 ng/ml enantiomer.

Bupivacaine↗

PubMed1994

Effects of subanesthetic halothane on the ventilatory responses to hypercapnia and acute hypoxia in healthy volunteers.

BACKGROUND: The peripheral chemoreceptors are responsible for the ventilatory response to hypoxia (acute hypoxic response) and for 30% of the normoxic hypercapnic ventilatory response. To quantify the effects of subanesthetic concentrations of halothane on the respiratory control system, in particular on the peripheral chemoreceptors, we studied the response of humans to carbon dioxide and oxygen at two subanesthetic concentrations of halothane. METHODS: Square-wave changes in end-tidal carbon dioxide tension (7.5-11.3 mmHg) and step decreases in end-tidal oxygen tension (arterial hemoglobin oxygen saturation 82 +/- 2%; duration of hypoxia 5 min) were performed in nine healthy male subjects during 0, 0.05 (HA-1), and 0.1 minimum alveolar concentration (HA-2) halothane. Each hypercapnic response was separated into a fast, peripheral component and a slow, central component, characterized by a time constant, carbon dioxide sensitivity, time delay, and off-set. RESULTS: Fifty-six carbon dioxide responses and 27 oxygen responses were obtained. The peripheral carbon dioxide sensitivities averaged to 0.76 +/- 0.14 l.min-1.mmHg-1 (control), 0.50 +/- 0.12 l.min-1.mmHg-1 (HA-1), and 0.30 +/- 0.08 l.min-1.mmHg-1 (HA-2; P < 0.01 vs. control). The central carbon dioxide sensitivity did not differ significantly among treatment groups (control, 1.47 +/- 0.22 l.min-1.mmHg-1; HA-1, 1.41 +/- 0.51 l.min-1.mmHg-1; and HA-2, 1.23 +/- 0.30 l.min-1.mmHg-1). The time constants of the central chemoreflex loop showed a large decrease during the administration of 0.1 minimum alveolar concentration halothane. The acute hypoxic response declined from 15.0 +/- 3.9 l.min-1 to 10.9 +/- 2.9 l.min-1 (HA-1) and 4.8 +/- 1.4 l.min-1 (HA-2; P < 0.01 vs. control and HA-1). All values are means +/- SEM. CONCLUSIONS: The results show depression of the ventilatory responses to hypoxia and hypercapnia during inhalation of subanesthetic concentrations of halothane. The depression is attributed to a selective effect of halothane on the peripheral chemoreflex loop. The oxygen and carbon dioxide responses mediated by the peripheral chemoreceptors are affected proportionally. It is argued that the decrease in central time constants is caused by an effect of halothane on central neuronal dynamics.

Administration, Inhalation↗

PubMed1994

Pharmacokinetics of alfentanil after epidural administration. Investigation of systemic absorption kinetics with a stable isotope method.

BACKGROUND: The effects of epidurally administered alfentanil may be due in part to its uptake into the systemic circulation. Therefore we examined the systemic absorption kinetics after epidural injection of alfentanil. METHODS: Pharmacokinetics were determined using a stable isotope method in ten patients, undergoing lower abdominal surgery under general anesthesia. After epidural injection of 0.68 mg deuterium-labeled alfentanil (alfentanil-d5), 1 mg unlabeled alfentanil was administered over 1 h by an intravenous infusion. Blood samples were collected for 12 h. Concentrations of alfentanil and alfentanil-d5 were measured by a combination of gas chromatography and mass fragmentography. The systemic absorption profiles of alfentanil-d5 were determined by deconvolution of the plasma alfentanil-d5 concentrations with the biexponential unit disposition functions, derived from the intravenous data. In addition, data were analyzed by moment analysis. RESULTS: The mean (+/- SD) steady-state volume of distribution, total plasma clearance, elimination half-life and mean residence time, derived from the unlabeled alfentanil concentration-time data, were 43.2 +/- 19.5 1,418 +/- 129 ml/min, 119 +/- 34 min, and 103 +/- 26 min, respectively. The absorption of alfentanil-d5 was monophasic in most patients. The mean systemic availability and mean absorption time derived from the deconvolution data were 100 +/- 17% and 114 +/- 24 min. The values determined by moment analysis were 107 +/- 18% and 112 +/- 36 min, respectively. CONCLUSIONS: After epidural administration alfentanil is slowly absorbed into the general circulation. Resulting plasma concentrations are very low and do not contribute appreciably to the systemic opioid effect.

Absorption↗

PubMed1994

Influence of a subanesthetic concentration of halothane on the ventilatory response to step changes into and out of sustained isocapnic hypoxia in healthy volunteers.

BACKGROUND: In humans the ventilatory response to isocapnic hypoxia is biphasic: an initial increase in minute ventilation (VE) from baseline, the acute hypoxic response, is followed after 3-5 min by a slow ventilatory decay, the hypoxic ventilatory decline, and a new steady state, 25-40% greater than baseline VE, is reached in about 15-20 min. The transition from 20 min of isocapnic hypoxia into normoxia results in a rapid decrease in VE, the off-response. In humans, halothane, at subanesthetic concentrations, is known to decrease the acute hypoxic response. In order to investigate the effects of halothane on sustained hypoxia we quantified the effects of 0.15 minimum alveolar concentration halothane on the ventilatory response at the onset of 20 min of hypoxia and at the termination of 20 min of hypoxia by normoxia in healthy volunteers. METHODS: Step changes in end-tidal oxygen tension were performed against a background of constant mild hypercapnia (end-tidal carbon dioxide tension about 1 mmHg above individual resting values) in fourteen male subjects. The end-tidal oxygen tension was forced as follows: 5-10 min at 110 mmHg, 20 min at 44 mmHg, and 10 min at 110 mmHg. In each subject we performed one trial before and one during 0.15 minimum alveolar concentration halothane administration. RESULTS: Ten responses into hypoxia and nine out of hypoxia were considered for analysis. All control trials were performed during wakefulness. Using behavioral characteristics, the central nervous system arousal state of the subjects during halothane inhalation was defined as "anesthesia-induced hypnosis." The acute hypoxic response averaged 10.4 +/- 4.7 l/min for control versus 3.7 +/- 2.4 l/min for halothane trials (P < 0.01). The hypoxic ventilatory decline was 4.8 +/- 2.5 l/min versus 3.9 +/- 2.9 l/min (NS), the off-response was 6.7 +/- 3.2 l/min versus 3.7 +/- 3.0 l/min (P < 0.05) for control versus halothane, respectively. All values are mean +/- SD. CONCLUSIONS: Our results indicate that halothane caused VE to be less than control levels during acute and sustained hypoxia as well as when sustained hypoxia is replaced by normoxia. It is argued that the depression of VE during acute hypoxia is attributed to an effect of halothane on the peripheral chemoreceptors. During sustained hypoxia halothane had no effect on the magnitude of the hypoxic ventilatory decrease, which is probably related to an increase by halothane of inhibitory neuromodulators within the central nervous system. With halothane, the ventilatory decrease when sustained hypoxia is replaced by normoxia is related to the removal of the hypoxic drive at the site of the peripheral chemoreceptors.

Adult↗

PubMed1994

Does subanesthetic isoflurane affect the ventilatory response to acute isocapnic hypoxia in healthy volunteers?

BACKGROUND: Differences in results studying the effects of subanesthetic concentrations of volatile agents on the hypoxic ventilatory response may be related to the conditions under which the subjects were tested. In this study we investigated the effects of 0.1 minimum alveolar concentration (MAC) of isoflurane on the hypoxic ventilatory response without and with audiovisual stimulation. METHODS: Step decreases in arterial hemoglobin oxygen saturation from normoxia into hypoxia (arterial hemoglobin oxygen saturation 80% +/- 2%; duration of hypoxia 5 min) were performed in ten healthy subjects. We obtained four responses per subject: one without isoflurane in a darkened, quiet room; one without isoflurane with audiovisual input (music videos); one in a darkened room at 0.1 MAC isoflurane; and one at 0.1 MAC isoflurane with audiovisual input (subjects were addressed to keep their eyes open). Experiments were performed against a background of isocapnia (end-tidal carbon dioxide tension 1-1.4 mmHg above initial resting values). RESULTS: The hypoxic responses averaged 0.54 +/- 0.09 1.min-1.%-1 (without isoflurane in a darkened, quiet room), 0.27 +/- 0.06 l-min-1.%-1 (in a darkened room at 0.1 MAC isoflurane; P < 0.01), 0.56 +/- 0.131.min-1.%-1 (without isoflurane with audiovisual input), and 0.47 +/- 0.13 l.min-1.%-1 (at 0.1 MAC isoflurane with audiovisual input). Values are means +/- SE. During 0.1 MAC isoflurane administration, all subjects showed a depressed hypoxic response when not stimulated, while with stimulation two subjects had an increased response, four a decreased response and four an unchanged response compared to control. CONCLUSIONS: We observed an important effect of the study conditions on the effects that 0.1 MAC isoflurane has on the hypoxic ventilatory response. A depressant effect of subanesthetic isoflurane was found only when external stimuli to the subjects were absent. With extraneous audiovisual stimuli the effect of isoflurane on the response to hypoxia was more variable. On the average, however, the response then was not depressed by isoflurane.

Acoustic Stimulation↗

PubMed1994

Efficacy of epidurally administered sufentanil versus bupivacaine during thoracic surgery. A randomised placebo-controlled double-blind study.

The efficacy of thoracic epidural sufentanil 50 micrograms was compared with bupivacaine 0.5% with adrenaline 5 micrograms.ml-1 (dose 40 mg) or saline, in 30 patients (n = 10 in each group) undergoing lateral thoracotomy. Sufentanil, bupivacaine or saline was administered epidurally after induction of anaesthesia with sufentanil 1 microgram.kg-1 and thiopentone 2-5 mg.kg-1. Anaesthesia was maintained with nitrous oxide 66% and halothane 0.3%. Supplementary sufentanil 25 micrograms was given whenever the systolic arterial blood pressure increased more than 15 mmHg above the pre-operative value, whenever heart rate exceeded 90 beat.min-1 in the absence of hypovolaemia, or when other autonomic or somatic signs occurred. Fewer patients in the epidural sufentanil (n = 4, p < 0.005) and bupivacaine (n = 1, p < 0.001) groups required supplementary sufentanil compared to the placebo group, in which all patients needed supplementary sufentanil, but there was no statistical difference between the sufentanil and bupivacaine groups. One or more hypotensive episodes occurred in five patients in the sufentanil group, in all patients in the bupivacaine group and in no patient in the placebo group, and the differences were significant (p < 0.02).

Adolescent↗

PubMed1994

An intra-operative comparison of lumbar with thoracic epidural sufentanil for thoracotomy.

The efficacy of thoracic epidural sufentanil 50 micrograms was compared with lumbar epidural sufentanil 50 micrograms in 30 patients (n = 15 in each group) undergoing lateral thoracotomy. Sufentanil was administered epidurally after induction of anaesthesia with sufentanil 1 microgram.kg-1 and thiopentone 2-5 mg.kg-1 intravenously. Anaesthesia, nitrous oxide 66%, halothane 0.3% and sufentanil 25 micrograms intravenously were given whenever the systolic arterial blood pressure increased more than 15 mmHg above the preoperative value and heart rate exceeded 90 beat.min-1 in the absence of hypovolaemia, or when other autonomic or somatic signs were seen. Four patients in the thoracic epidural group and five in the lumbar epidural group needed supplementary sufentanil. Six patients in the thoracic epidural group and three in the lumbar epidural group each had a single hypotensive episode. Lumbar and thoracic epidural sufentanil are equally effective in contributing to intra-operative analgesia for lateral thoracotomy.

Adult↗

PubMed1994

Plasma concentrations of alfentanil following epidural administration.

The plasma concentration-time profile of alfentanil following epidural administration was determined in eight patients undergoing lower abdominal surgery under nitrous oxide (66%)-oxygen (33%)-halothane (0.3%) anaesthesia, supplemented with intravenous sufentanil. Alfentanil (1 mg) was administered epidurally before induction of general anaesthesia. Blood samples for the determination of plasma alfentanil concentrations by capillary gas chromatography were collected at intervals until 12 h after the epidural injection. Peak plasma concentrations [mean (SD)] were 9.7 (2.3)ng.ml-1, and were attained in a median (range) time of 90 (30-120) min. The results suggest that alfentanil is slowly absorbed from the epidural space into the general circulation.

Adult↗

PubMed1994

The effect of epidural administration of alfentanil on intra-operative intravenous alfentanil requirements during nitrous oxide-oxygen-alfentanil anaesthesia for lower abdominal surgery.

The effects of epidural administration of alfentanil on the intravenous alfentanil dose requirements and the plasma concentrations required to suppress responses to surgical stimulation during nitrous oxide-oxygen-alfentanil anaesthesia in 20 patients undergoing lower abdominal surgery were studied. Before induction of anaesthesia, patients in one group (E) received an epidural injection of 1 mg alfentanil, followed by an epidural infusion of alfentanil 0.2 mg.h-1 until skin closure, whilst patients in the other group (C, control) received a continuous infusion of sodium chloride via a sham catheter in order to blind the main investigator to the treatment. Anaesthesia was induced and maintained with nitrous oxide (66%) in oxygen and a 'target'-controlled intravenous infusion of alfentanil. During surgery, the 'target' alfentanil concentration was increased or decreased according to patients' responses. The number of responses to surgical stimulation was smaller in patients from group E (median 1, range 0-3) than in patients from group C (median 4, range 1-15; p < 0.005), even though the alfentanil intravenous infusion rates were smaller in group E [mean (SD): 1.6(0.5) micrograms.kg-1 min-1] than in group C [2.9(1.2) micrograms.kg-1 min-1, p < 0.02]. Both the lowest concentrations associated with no response [133(40) ng.ml-1] and the highest concentrations associated with a response [155(65) ng.ml-1] in group E were lower than those in group C [238(100) ng.ml-1, p < 0.01 and 334(163) ng.ml-1, p < 0.05, respectively]. We concluded that epidural administration of alfentanil reduces intravenous alfentanil requirements during nitrous oxide-oxygen-alfentanil anaesthesia for lower abdominal surgery. The results indicate a spinal mechanism of action of epidural alfentanil.

Abdomen↗

PubMed1994

Pharmacokinetics of the enantiomers of bupivacaine following intravenous administration of the racemate.

1. The pharmacokinetics of R(+)-bupivacaine and S(-)-bupivacaine were investigated following a 10 min intravenous infusion of the racemate (dose 30 mg) in 10 healthy males. 2. The fractions unbound of R(+)- and S(-)-bupivacaine in pre-dose plasma were determined for each subject after in vitro addition of rac-bupivacaine (concentration of each enantiomer: approximately 300 ng ml-1). 3. The total plasma clearance of R(+)-bupivacaine (mean +/- s.d.: 0.395 +/- 0.076 l min-1) was greater (P < 0.0001) than that of S(-)-bupivacaine (0.317 +/- 0.067 l min-1). The volumes of distribution of R(+)-bupivacaine at steady state (84 +/- 29 l) and during the terminal log-linear phase (117 +/- 47 l) were larger (P < 0.0002) than those of S(-)-bupivacaine (54 +/- 20 l and 71 +/- 34 l, respectively). The terminal half-life (210 +/- 95 min) and mean residence time (215 +/- 74 min) of R(+)-bupivacaine were longer than those of S(-)-bupivacaine (157 +/- 77 min, P < 0.01, and 172 +/- 55 min, P < 0.02, respectively). 4. The free percentage of R(+)-bupivacaine (6.6 +/- 3.0 %) was greater (P < 0.0002) than that of S(-)-bupivacaine (4.5 +/- 2.1 %). 5. The plasma clearance of unbound R(+)-bupivacaine (7.26 +/- 3.60 1 min-1) was smaller (P < 0.01) than that of S(-)-bupivacaine (8.71 +/- 4.27 l min-1). Volumes of distribution based on unbound R(+)-bupivacaine concentrations (Vuss: 1576 +/- 934 l; Vu: 2233 +/- 1442 l) did not differ from those of S(-)-bupivacaine (Vuss: 1498 +/- 892 l; Vu: 1978 +/- 1302 l). 6. The enantioselective systemic disposition of bupivacaine can to a large extent be attributed to differences in the degree of plasma binding of the enantiomers.

Adult↗

PubMed1994

Spinal anesthesia with ropivacaine: a double-blind study on the efficacy and safety of 0.5% and 0.75% solutions in patients undergoing minor lower limb surgery.

The purpose of this study was to determine the clinical efficacy and safety of ropivacaine as a local anesthetic for spinal anesthesia. Forty patients between the ages of 18 and 75 yr, scheduled for minor lower limb surgery, were studied. They were randomly allocated to receive either 3 mL glucose-free 0.5% (15 mg) or 0.75% (22.5 mg) ropivacaine in a double-blind fashion. The subarachnoid puncture was performed with a 26-gauge Quincke-point needle at the L3-4 interspace with the patients in the sitting position. The onset of analgesia to pinprick was similar with both concentrations. The median (range) upper level of analgesia obtained with the 0.5% solution was T11 (L4-T5) and was T10-11 (L4-T4) with the 0.75% solution. The duration of analgesia at T12 (P < 0.01) and the total duration of analgesia (P < 0.002) were longer in the 0.75% group. In addition, the area under the number of blocked segments versus time curve was larger with the 0.75% ropivacaine solution (P < 0.001). The incidence of complete motor block of the lower limbs was higher (P < 0.02) and the total duration of motor block longer (P < 0.002) in the 0.75% group. No unexpected adverse events were registered. We conclude that subarachnoid injection of glucose-free ropivacaine solutions results in a variable spread of analgesia, mostly accompanied by a good quality of motor block, in particular with the 0.75% solution.

Adolescent↗

PubMed1993

Preoperative interpleural administration of sufentanil or bupivacaine reduces intraoperative intravenous sufentanil requirements during thoracotomy.

The efficacy of interpleural administration of sufentanil, 50 micrograms, was compared with that of 150 mg of bupivacaine, 0.5%, with epinephrine, 5 micrograms/mL, or saline, in 30 patients (N = 10 in each group) undergoing lateral thoracotomy. Sufentanil, bupivacaine, or saline was administered interpleurally after induction of anesthesia with sufentanil, 1 microgram/kg intravenously, and thiopental, 2 to 5 mg/kg. Anesthesia was maintained with nitrous oxide, 66%, and halothane, 0.3% inspired concentration. Supplementary intravenous sufentanil, 25 micrograms, was given whenever the systolic arterial blood pressure increased more than 15 mmHg above the preoperative value, heart rate exceeded 90 beats/min in the absence of hypovolemia, or when other autonomic or somatic signs of inadequate anesthesia occurred. The additional intravenous sufentanil requirement and the incidence of hypotension were compared between the groups. All patients in the placebo group needed supplementary sufentanil. Significantly fewer patients in the interpleural sufentanil (N = 1, P < 0.0002) and bupivacaine (N = 1, P < 0.0002) groups required supplementary sufentanil compared to the placebo group (N = 10). The time from interpleural administration of the study drug to the first administration of postoperative analgesic was significantly longer (P < 0.001) in the sufentanil group (228 +/- 72 min) and bupivacaine group (242 +/- 76 min) compared to the placebo group (141 +/- 50 min). It was concluded that interpleural administration of either sufentanil or bupivacaine contributes to intraoperative analgesia during thoracotomy.

Adult↗

PubMed1993

Computer-controlled infusion of alfentanil for postoperative analgesia. A pharmacokinetic and pharmacodynamic evaluation.

BACKGROUND: Although computer-controlled infusion (CCI) of alfentanil has been shown to be effective intraoperatively, this technique has not been validated for postoperative use. Therefore, the authors examined the efficacy of this technique in providing postoperative pain relief. The study comprised both a validation of published pharmacokinetic data sets and the definition of the minimum effective analgesic concentrations after major orthopedic surgery. METHODS: The bias and inaccuracy of the implemented pharmacokinetic data set were examined, in 20 patients who had undergone major orthopedic surgery, by determination of the median performance error (MDPE) and median absolute performance error (MDAPE). The performance of two other published pharmacokinetic data sets was also examined by simulating the plasma concentrations that would have been predicted, had these data sets been implemented. The minimum effective analgesic concentrations (MEAC) were determined at the following time points: at the onset of pain, at 9:00 PM on the day of surgery, and at 9:00 AM and 9:00 PM on the first postoperative day. RESULTS: Measured plasma concentration-time profiles generally were parallel to the target concentration-time profiles. The MDPE and MDAPE obtained were 12% and 28%, respectively. The MEACs ranged from < 1 to 175 ng/ml and showed substantial interindividual variability. The median MEACs at the four study times were 59, 52, 65, and 43 ng/ml. The MEAC at 9:00 PM on the first postoperative day was significantly lower than those at the other study times (P < 0.05). CONCLUSION: Computer-controlled infusion of alfentanil provides adequate postoperative analgesia. The study demonstrated that pharmacokinetic data sets that are useful for intraoperative CCI of alfentanil are equally valid in the postoperative phase. Although required plasma concentrations of alfentanil are reasonably stable in time, interindividual variations are large, necessitating individual titration.

Adult↗

PubMed1992

Failure of anaesthesia after accidental subdural catheter placement.

A case is described where an epidural anaesthetic was complicated by dural puncture, following which attempted conversion to a continuous subarachnoid infusion technique resulted in failure of anaesthesia. Accidental subdural catheter placement was confirmed radiologically, subdural spread of solution being demonstrated; however, only minimal anaesthetic effects were produced.

Adult↗

PubMed1992

Continuous interpleural infusion of bupivacaine for postoperative analgesia after surgery with flank incisions: a double-blind comparison of 0.25% and 0.5% solutions.

Postoperative analgesia, as assessed by visual analogue scale scores (0-10) and patient-controlled analgesia morphine requirements, pulmonary function (forced vital capacity and forced expiratory volume in 1 s), and plasma bupivacaine concentrations were studied in patients receiving interpleural blockade with bupivacaine after surgery with a flank incision. Two groups of 10 patients received either 0.5% or 0.25% bupivacaine, both with epinephrine (5 micrograms/mL). Pain relief was initiated when patients had visual analogue scale scores greater than or equal to 4. Patients received 21 mL of bupivacaine 0.25% or 0.5% in a double-blind fashion. One hour later, a continuous infusion of 5 mL/h of the study solution was started. At the same time, patient-controlled analgesia became accessible to the patients. The onset time of pain relief and the area under the visual analogue scale score-time curves over the first 8 h were similar in both groups. Patient-controlled analgesia morphine use was also similar in the 0.25% (21.3 +/- 14.6 mg) and 0.5% (21.0 +/- 16.0 mg) groups (mean +/- SD). In both groups, forced vital capacity and forced expiratory volume in 1 s improved significantly within 60 min (P less than 0.05). Peak plasma concentrations (Cmax) and the area under the plasma concentration-time curve (AUC) over 24 h were higher (P less than 0.001) in the 0.5% group (Cmax, 1.47 +/- 0.37 micrograms/mL; AUC, 1511 +/- 323 micrograms.mL-1.min) than those in the 0.25% group (Cmax, 0.55 +/- 0.22 micrograms/mL; AUC, 680 +/- 118 micrograms.mL-1.min) (mean +/- SD).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

Cognitive function after spinal or general anesthesia for transurethral prostatectomy in elderly men.

Cognitive functions in 53 elderly men who underwent a transurethral prostatectomy were assessed pre-operatively and 4 days and 3 months post-operatively. Thirteen patients had a preference for one particular type of anesthesia, and the remaining 40 were randomly allocated to receive either spinal or general anesthesia. Cognitive function was not different between the groups receiving different types of anesthesia at either time point and did not decrease post-operatively. No pre- or perioperative variable could distinguish the subgroup of patients who had a post-operative decrease of 2 points or more on the Mini-Mental State Examination. No difference in post-operative performance was found in the patient groups with pre-operative Mini-Mental State Examination scores above or under their age-specific norm. It is concluded that neither hospitalization nor the two forms of anesthesia investigated cause a decrease in cognitive function in elderly men.

Aged↗

PubMed1990

Single-dose interpleural versus intercostal blockade: nerve block characteristics and plasma concentration profiles after administration of 0.5% bupivacaine with epinephrine.

Analgesic effects and plasma concentration profiles after interpleural (IP) or intercostal (IC) administration of 21 mL of 0.5% bupivacaine with epinephrine (5 micrograms/mL) were studied in 24 patients (IP group: n = 12; IC group: n = 12) who had undergone cholecystectomy or renal surgery. The number of blocked dermatomes, as assessed by pinprick, was more variable between patients in the IP group (2-9 dermatomes) than in the IC group (6-8 dermatomes). The mean time intervals from the injection to two-dermatome regression and to first need for additional pain medication were 4 h (IP) and 5.5 h (IC) (P less than 0.02) and 5.3 h (IP) and 9.8 h (IC) (P = 0.002), respectively. The degree of postoperative pain was evaluated by means of a visual analogue scale. This gradually increased during the first 4 h in the IP group (P less than 0.001), but not in the IC group. Peak bupivacaine concentrations in arterial plasma were approximately 10% higher than those in venous plasma and were attained more rapidly. Peak arterial plasma concentrations after IP injection (2.07 +/- 0.53 micrograms/mL) were significantly higher (P less than 0.005) than those after IC administration (1.36 +/- 0.48 micrograms/mL). Peak venous plasma concentrations showed a similar difference (IP: 1.86 +/- 0.45 micrograms/mL; IC: 1.21 +/- 0.48 micrograms/mL; P less than 0.005). Peak concentrations were attained later after IP injection both in arterial (IP: 16.3 +/- 4.6 min; IC: 8.8 +/- 5.4 min; P less than 0.002) and venous plasma (IP: 20.0 +/- 7.1 min; IC 13.3 +/- 6.9 min; P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗