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B W Brandom

Publications and source records attributed to B W Brandom.

54 records · Page 3Linked to original sources
PubMed1989

Clinical pharmacology of mivacurium chloride (BW B1090U) in children during nitrous oxide-halothane and nitrous oxide-narcotic anesthesia.

We determined the dose-response relationships of mivacurium (BW B1090U) in children (2-10 years) during nitrous oxide-halothane anesthesia (0.8% end-tidal) and during nitrous oxide-narcotic anesthesia. Neuromuscular blockade was monitored by recording the electromyographic activity of the adductor pollicis muscle resulting from supramaximal stimulation at the ulnar nerve at 2 Hz for 2 seconds at 10-second intervals. To estimate dose-response relationships, for each anesthetic background four subgroups of nine patients received single bolus doses of 20-120 micrograms/kg mivacurium. The ED50 and ED95 (estimated from linear regression plots of log-dose vs. probit of effect) were 52 micrograms/kg and 89 micrograms/kg during halothane anesthesia and 62 micrograms/kg and 103 micrograms/kg during narcotic anesthesia. Nine additional patients in each anesthetic group received 250 micrograms/kg mivacurium. Three of the 18 patients given 250 micrograms/kg mivacurium developed cutaneous flushing; in one of these mean arterial pressure decreased 32% for less than 1 minute; no significant changes in heart rate occurred. With the increase in mivacurium dose from 120 micrograms/kg to 250 micrograms/kg the times to onset of 90% and maximum neuromuscular block decreased by 0.5 to 1 minute, and the times to recovery of neuromuscular transmission to 5% (T5) or 25% (T25) increased by 2-4 minutes. The recovery index (T25-75) in patients anesthetized with halothane was 4.3 +/- 1.5 minute (mean +/- SD); the time to complete recovery (T4:1 greater than or equal to 0.75) was 19.8 +/- 7.4 minutes.

Age Factors↗
PubMed1989

Effects of cholestatic hepatic disease and chronic renal failure on alfentanil pharmacokinetics in children.

The role of the liver and the kidney in alfentanil metabolism has not been defined. The effects of cholestatic hepatic disease and chronic renal failure on the pharmacokinetics of alfentanil were evaluated in 9 children undergoing liver transplantation and 10 children undergoing kidney transplantation. These findings were compared with data from 10 children with normal hepatic and renal function undergoing other surgical procedures. There was no statistical difference among the 3 groups with respect to apparent volume of distribution, half-life, or clearance. In a subgroup of 3 patients undergoing liver transplantation alfentanil kinetics were determined both before and after the allograft was incorporated into the recipient's circulation. Though both volume of distribution and elimination half-life increased in the posttransplantation period, only the decrease in clearance was statistically significant. Thus, it appears that alfentanil may be a useful anesthetic agent in pediatric patients with cholestatic hepatic disease or chronic renal failure. The dose of alfentanil in these patients need not be altered except in the period immediately after liver transplantation.

Adolescent↗
PubMed1989

In vitro metabolism of mivacurium chloride (BW B1090U) and succinylcholine.

The in vitro rates of metabolism of mivacurium chloride and succinylcholine in pooled human plasma were compared. In addition, the rate of metabolism of mivacurium in buffered solutions of butyrylcholinesterase (E.C. 3.1.1.8) and acetylcholinesterase (E.C. 3.1.1.7) was determined. Succinylcholine concentrations were measured spectrophotometrically, and mivacurium concentrations were determined with a high-pressure liquid chromatographic assay. The hydrolysis of mivacurium in plasma followed first-order kinetics, and the rate of hydrolysis decreased as plasma was serially diluted. The Michaelis-Menten constant (Km) for mivacurium metabolism in plasma was 245 mumol/L, and the maximum velocity (Vmax) was 50 U/L; the Km for succinylcholine was 37 mumol/L, and Vmax was 74 U/L. At comparable multiples of the Km the hydrolysis rate of mivacurium was 70% of that of succinylcholine. Mivacurium was metabolized significantly in solutions containing butyrylcholinesterase, but only minimally in solutions containing acetylcholinesterase.

Butyrylcholinesterase↗
PubMed1989

Intravenous ranitidine antagonizes intense atracurium-induced neuromuscular blockade in rats.

The neuromuscular action of ranitidine, an H2-receptor antagonist, was investigated by determining its effect on atracurium-induced neuromuscular blockade in urethane-anesthetized and mechanically ventilated male Sprague-Dawley rats. An intravenous bolus and an infusion of atracurium were administered to produce a stable 93 +/- 5% (n = 11) neuromuscular blockade as judged by tibialis anterior muscle twitch response. Ranitidine administered as a 1, 5, or 10 mg/kg normal body weight IV bolus during continuous atracurium infusion produced marked antagonism of neuromuscular paralysis. The percentage of antagonism (25 +/- 9%; n = 4; 53 +/- 19%, n = 4; and 79 +/- 9%, n = 3, respectively) was linearly related to the dose of ranitidine (r = 0.86, P less than 0.05). These results suggest that IV ranitidine has a significant anticholinesterase action against atracurium-induced neuromuscular blockade.

Animals↗
PubMed1988

Pharmacokinetics of sufentanil in adolescent patients with chronic renal failure.

The role of the kidney in sufentanil elimination or metabolism has not been defined. The effects of chronic renal failure (CRF) on the pharmacokinetic profile of sufentanil were evaluated in six adolescent patients undergoing renal transplantation, and these findings were compared with data from age-matched control patients with normal renal function who were undergoing other surgical procedures. Patients with CRF weighed significantly less than did the control patients (28.7 +/- 5.7 vs 44.7 +/- 12.9 kg [mean +/- SD]). Although there was no statistical difference in the rate of clearance or apparent volume of distribution and half-life between the two groups, clearance and half-life were more variable among patients with CRF. In these patients, therefore, sufentanil dose must be carefully administered based on responses elicited in individual patients.

Adolescent↗
PubMed1988

Clinical pharmacology of doxacurium chloride (BW A938U) in children.

The neuromuscular effects of doxacurium were studied in 26 children during halothane-nitrous oxide-oxygen anesthesia. Neuromuscular blockade was measured using electromyographic activity of the adductor pollicis muscle after supramaximal stimulation of the ulnar nerve at 2 Hz for 2 seconds at 10-second intervals. To estimate the cumulative dose-response relation, nine patients received incremental doses of doxacurium (2.5-10 micrograms/kg); nine patients received 27.5 micrograms/kg (the estimated ED95); eight patients received 50 micrograms/kg (1.8 X ED95). The ED25, ED50, ED75, and ED95 (estimated from linear regression plots of log dose vs probit of effect) were 11.5, 14.8, 19.0, and 27.3 micrograms/kg, respectively. Clinical duration (T25) was 27.8 +/- 10.3 (mean +/- SD) minutes at 1 X ED95 and 50.6 +/- 15.6 minutes at 1.8 X ED95. Time to recovery of the train-of-four ratio to 0.75 was 63.1 +/- 32.9 minutes at 1 X ED95 and 108.5 +/- 25.7 minutes at 1.8 X ED95. There were no significant changes in heart rate or mean arterial pressure after bolus administration of any dose of doxacurium.

Age Factors↗
PubMed1988

Mivacurium chloride (BW B1090U)-induced neuromuscular blockade during nitrous oxide-isoflurane and nitrous oxide-narcotic anesthesia in adult surgical patients.

The neuromuscular and cardiovascular effects of mivacurium were studied in 90 adult patients during nitrous oxide-oxygen-isoflurane (n = 45, ISO group) and nitrous oxide-oxygen-narcotic (n = 45, BAL group) anesthesia. Neuromuscular blockade was measured using electromyographic activity of the adductor pollicis muscle after supramaximal stimulation of the ulnar nerve at 2 Hz for 2 seconds at 10-second intervals. To estimate dose-response relations, three subgroups of nine patients in the ISO group received mivacurium doses of 0.025, 0.03, and 0.04 mg/kg, respectively. Similarly, three subgroups of nine patients in the BAL group received mivacurium doses of 0.03, 0.04, and 0.05 mg/kg, respectively. The ED50 and ED95 of mivacurium in each group were estimated from linear regression plots of log dose vs probit of maximum percentage depression of neuromuscular function. The estimated ED50 values for the ISO and BAL groups were 0.029 and 0.041 mg/kg, respectively. The estimated ED95 values for the ISO and BAL groups were 0.045 and 0.058 mg/kg, respectively. Recovery indexes were measured in 26 patients who received ED95 or greater doses of mivacurium in either the ISO or BAL groups. The recovery index was shorter in the BAL group (5.5 +/- 1.6 minutes [n = 10]), than in the ISO group (7.4 +/- 3.0 minutes [n = 16]). The addition of isoflurane (0.5-0.75% end-tidal concentration) to nitrous oxide-narcotic anesthesia augments the degree of neuromuscular blockade from a given dose of mivacurium and also prolongs the recovery index.

Adult↗
PubMed1986

Pharmacokinetics of atracurium in anaesthetized infants and children.

The pharmacokinetics of atracurium were studied in infants and children anaesthetized with isoflurane and nitrous oxide in oxygen. There were no significant differences in volume of distribution (area) (139 v. 152 ml kg-1), clearance (5.1 v. 5.3 ml kg-1 min-1), T1/2 alpha (2.1 v. 2.0 min), or T1/2 beta (19.1 v. 20.3 min) between children with normal hepatic and renal function and those with moderately impaired hepatic function presenting for hepatic transplantation. There were significant differences in volume of distribution (area) (176 v. 139 ml kg-1) and in clearance of atracurium (9.1 v. 5.1 ml kg-1 min-1) between infants and children with normal excretory function. In infants the clearance of atracurium in ml m-2 min-1 (153 v. 133) tended to be greater and the T1/2 alpha and T1/2 beta tended to be shorter (1.0 v. 2.0 and 13.6 v. 19.1) than in children with normal excretory function; however, these trends did not reach statistical significance. Plasma laudanosine concentration was around 100 ng ml-1 greater in patients with liver disease than in normal children from 15-45 min following a bolus of atracurium 0.5 mg kg-1.

Anesthesia, Inhalation↗
PubMed1985

Enflurane, halothane and isoflurane do not inhibit angiotensin converting enzyme activity.

We studied the effect of halothane, enflurane and isoflurane on angiotensin converting enzyme (ACE) activity using [3H]-benzoyl-phenylalanyl-alanyl-proline (BPAP) as a substrate. Isolated rabbit lungs were perfused in a recirculating system in vitro with BPAP in Krebs-Ringer solution. The rate of metabolism and per cent metabolism were determined before and after treatment for 30 minutes with four MAC multiples of enflurane, halothane or isoflurane. The effects of the anaesthetics on ACE activity were determined by calculating per cent inhibition of metabolism of BPAP using data from the control and test period for each lung. The average metabolism of BPAP at 15 minutes during the control period was 76.5 per cent (+/- 1.92 SEM). No anaesthetic significantly inhibited metabolism of BPAP. Likewise there was no effect on BPAP first order kinetics. Although potent inhalation anaesthetics may alter the renin-angiotensin-aldosterone axis, they do not affect this crucial step.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1985

Atracurium infusion requirements in children during halothane, isoflurane, and narcotic anesthesia.

We were interested in determining the dose-response relationship of atracurium in children (2-10 yr) during nitrous oxide-isoflurane anesthesia (1%) and the atracurium infusion rate required to maintain about 95% neuromuscular blockade during nitrous oxide-halothane (0.8%), nitrous oxide-isoflurane (1%), or nitrous oxide-narcotic anesthesia. Neuromuscular blockade was monitored by recording the electromyographic activity of the adductor pollicis muscle resulting from supramaximal stimulation at the ulnar nerve at 2 Hz for 2 sec at 10-sec intervals. To estimate dose-response relationships, three groups of five children received 80, 100, 150 micrograms/kg atracurium, respectively. During isoflurane anesthesia, the neuromuscular block produced by 80 micrograms/kg was 23.6% +/- 6.5 (mean +/- SEM), by 100 micrograms/kg was 45% +/- 7.2, and by 150 micrograms/kg was 64% +/- 8.7. The ED50 and ED95 (estimated from linear regression plots of log dose vs probit of effect) were 120 micrograms/kg and 280 micrograms/kg, respectively. At equipotent concentrations, halothane and isoflurane augment atracurium neuromuscular block to the same extent, compared to narcotic anesthesia. Atracurium steady-state infusion requirements averaged 6.3 +/- 0.6 micrograms . kg-1 . min-1 during halothane or isoflurane anesthesia; the requirements during balanced anesthesia were 9.3 +/- 0.8 micrograms . kg-1 . min-1 (P less than 0.05). There was no evidence of cumulation during prolonged atracurium infusion.

Anesthesia, General↗
PubMed1984

Clinical pharmacology of atracurium in infants.

The neuromuscular effects of atracurium were studied in 25 infants anesthetized with 1.0% end-tidal halothane and N2O-O2. Neuromuscular blockade was monitored by recording the electromyographic activity of the adductor pollicis muscle resulting from supramaximal stimulation of the ulnar nerve at 2 Hz for 2 sec at 10-sec intervals. To estimate dose-response relationships, three groups of five infants received 60, 80, and 100 micrograms/kg atracurium, respectively; another ten infants received 300 micrograms/kg (2 X ED95). The neuromuscular block produced by 60 micrograms/kg was 27% +/- 10.9 (SEM), by 80 micrograms/kg was 34% +/- 8.0 and from 100 micrograms/kg was 70% +/- 8.3. The ED50 and ED95 (estimated from linear regression plots of log dose vs probit of effect) were 85 micrograms/kg and 150 micrograms/kg, respectively. Neuromuscular blockade lasted 23 +/- 1.6 min at 1 X ED95 and 32.5 +/- 5.2 min at 2 X ED95. Changes in heart rate and mean arterial pressure were clinically insignificant.

Adolescent↗
PubMed1983

Clinical pharmacology of atracurium in paediatric patients.

The potency of atracurium was determined in adolescents and children during nitrous oxide-halothane and nitrous oxide-thiopentone-fentanyl anaesthesia using single dose-response curves. Dose-response curves were parallel. The effective doses producing 95% twitch depression (ED95) (mg kg-1) during nitrous oxide-halothane were larger in younger children than in the adolescents. Halothane (0.8% end-tidal) did not significantly potentiate atracurium when compared with thiopentone-fentanyl. On a microgram m-2 basis there was no difference in the ED95 between patients of different age or those anaesthetized with different techniques. At approximately 95% twitch depression intubating conditions were excellent in all groups. Minimal cardiovascular effects were noted at several multiples of the ED95.

Adolescent↗
PubMed1983

Uptake and distribution of halothane in infants: in vivo measurements and computer simulations.

We measured uptake of halothane (the fraction of halothane in expired gas divided by the fraction of halothane in inspired gas, FE/FI) with a mass spectrometer over time in 7 infants less than 3 months of age. FE/FI for halothane in these infants increased more rapidly than has been described in adults by others. In addition, we developed a mathematical model for halothane uptake and distribution that incorporates age-dependent anatomic and physiologic parameters (alveolar ventilation, functional residual capacity, cardiac output, brain volume, etc). The model closely predicts FE/FI for halothane measured in the infants. At 5 min observed FE/FI was 0.67, at 15 min observed FE/FI was 0.80, while the predicted FE/FI values were 0.65 and 0.82, respectively. The model predicts that the myocardial and brain halothane concentrations will increase more rapidly in the infant than in the adult. Achievement of high myocardial halothane concentrations early in the anesthetic induction may cause the hypotension and bradycardia commonly seen in infants. Sensitivity of the infant myocardium to halothane would further exacerbate the effect of more rapid myocardial uptake.

Adult↗
PubMed1982

Enflurane, halothane, and isoflurane inhibit removal of 5-hydroxytryptamine from the pulmonary circulation.

We were interested in determining the effect of enflurane, halothane, and isoflurane on the uptake and removal of 5-hydroxytryptamine (5-HT) and phenylethylamine (PEA) from the lung. Isolated rabbit lungs were perfused in a recirculating system in vitro with 0.1 microM [14C]5-HT or 0.1 microM [14C]PEA in Krebs-Ringer solution. The rate of removal and percentage of removal of the bioamines were determined before and after either 1, 2, or 4 MAC multiples of the potent anesthetics. Because of variation in removal of bioamines among lungs from different animals, the effects of anesthetics on bioamine removal were determined by calculating the percentage of inhibition of removal using data from the control and test period for each lung. At 2 MAC concentrations, the anesthetics inhibited 5-HT removal 11.1%, at 4 MAC concentrations the anesthetics inhibited 5-HT removal 29.8% and significantly prolonged the half-life (t 1/2) of 5-HT removal. There was significant (10.8%) inhibition of PEA removal at 4 MAC concentrations for the three anesthetics. As uptake of 5-HT is the rate-limiting step in 5-HT removal, these data demonstrate a uniform depression of 5-HT uptake by the three potent anesthetics. The rate-limiting step of PEA uptake, metabolism by monoamine oxidases, is inhibited at 4 MAC concentrations of anesthetics.

Anesthetics↗
PubMedDate not supplied

Mivacurium infusion during nitrous oxide-isoflurane anesthesia: a comparison with nitrous oxide-opioid anesthesia.

STUDY OBJECTIVE: To determine the potentiation of the neuromuscular blockade induced by a titrated infusion of mivacurium in the presence of isoflurane versus a nitrous oxide (N2O)-opioid anesthesia. DESIGN: An open-label, controlled study. SETTING: The inpatient anesthesia service of two university medical centers. PATIENTS: Thirty adults divided into two groups. INTERVENTION: An intravenous infusion of mivacurium during anesthesia with N2O-opioid or N2O-isoflurane. MEASUREMENTS AND MAIN RESULTS: A neuromuscular blockade was monitored by recording the electromyographic activity of the adductor pollicis muscle resulting from supramaximal stimulation at the ulnar nerve at 2 Hz for 2 seconds at 10-second intervals. The mivacurium infusion rate was significantly less in the presence of isoflurane [4.0 +/- 0.8 micrograms/kg/min (mean +/- SEM)] than during N2O-opioid anesthesia (6.4 +/- 0.6 micrograms/kg/min). The recovery rates did not differ between anesthetic groups. After the termination of the infusion, spontaneous recovery to T4/T1 of at least 0.75 occurred in an average of 17.9 +/- 1.5 minutes, with a mean recovery index (T25-75) of 6.0 +/- 0.7 minutes. CONCLUSION: Isoflurane anesthesia reduces the infusion rate of mivacurium required to produce about 95% depression of neuromuscular function.

Adult↗
PubMedDate not supplied

The incidence of tissue coring during the performance of caudal injection in children.

BACKGROUND AND OBJECTIVES: The performance of caudal injection (CI) has become a routine part of pediatric anesthesia. The intraoperative and immediate postoperative complications of CIs have been reported extensively. Although the long-term consequences of CI are unknown, they may include the development of epidermoid tumors in the spinal canal. Such tumors have been attributed to tissue coring (the process by which pieces of tissue are removed by a needle as it passes through the tissue) and the subdural deposition of such tissue. METHODS: In this study, we examine the internal needle of 20-gauge i.v. cannulae from 50 CIs for evidence of tissue coring. RESULTS: We found a total coring incidence of 54% (95% confidence interval = 40-68%). Epidermal tissue was present in 33% of the positive samples. Fat was present in 67% of the positive samples and bloody material in 26%. This study provides an estimate (with a 95% confidence interval) of the rate of coring during CI performed with hollow point needles. CONCLUSIONS: These findings suggest that technical modifications may improve patient safety. The results also have implications for long-term follow-up of caudal anesthetics. Techniques for reducing the incidence of tissue coring during the performance of CI are discussed.

Anesthesia, Caudal↗