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Lipshutz AKM, Caldwell JE, Robinowitz DL, Gropper MA. An analysis of near misses identified by anesthesia providers in the intensive care unit. BMC Anesthesiol 2015; 15:93. [PMID: 26082147 PMCID: PMC4468961 DOI: 10.1186/s12871-015-0075-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 06/09/2015] [Indexed: 11/23/2022] Open
Abstract
Background Learning from adverse events and near misses may reduce the incidence of preventable errors. Current literature on adverse events and near misses in the ICU focuses on errors reported by nurses and intensivists. ICU near misses identified by anesthesia providers may reveal critical events, causal mechanisms and system weaknesses not identified by other providers, and may differ in character and causality from near misses in other anesthesia locations. Methods We analyzed events reported to our anesthesia near miss reporting system from 2009 to 2011. We compared causative mechanisms of ICU near misses with near misses in other anesthesia locations. Results A total of 1,811 near misses were reported, of which 22 (1.2 %) originated in the ICU. Five causal mechanisms explained over half of ICU near misses. Compared to near misses from other locations, near misses from the ICU were more likely to occur while on call (45 % vs. 19 %, p = 0.001), and were more likely to be associated with airway management (50 % vs. 12 %, p < 0.001). ICU near misses were less likely to be associated with equipment issues (23 % vs. 48 %, p = 0.02). Conclusions A limited number of causal mechanisms explained the majority of ICU near misses, providing targets for quality improvement. Errors associated with airway management in the ICU may be underappreciated. Specialist consultants can identify systems weaknesses not identified by critical care providers, and should be engaged in the ICU patient safety movement.
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Affiliation(s)
- Angela K M Lipshutz
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, 505 Parnassus Avenue, San Francisco, CA, 94143, USA.
| | - James E Caldwell
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, 505 Parnassus Avenue, San Francisco, CA, 94143, USA.
| | - David L Robinowitz
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, 505 Parnassus Avenue, San Francisco, CA, 94143, USA.
| | - Michael A Gropper
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, 505 Parnassus Avenue, San Francisco, CA, 94143, USA.
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Abstract
Sugammadex is a cyclodextrin molecule that encapsulates and inactivates rocuronium and vecuronium. As a result, any degree of neuromuscular block produced by rocuronium or vecuronium can be rapidly and completely reversed without autonomic effects. Because sugammadex is optimised for reversing rocuronium it is most likely to be used in conjunction with this drug. Sugammadex will allow deep levels of block to be maintained until the very end of surgery, and will allow block to be reversed at any time after rocuronium administration, even just a few minutes. The recommended dose-range is 2-16 mg.kg-1 (ascender), depending on the level of block. The availability of sugammadex reversal may increase the use of rocuronium, and decrease the use of suxamethonium and benzylisoquinoline neuromuscular blocking drugs. In addition, it will certainly increase pharmacy costs, which may be offset by faster recovery and discharge from the post-anesthesia recovery unit. Sugammadex may also change monitoring practices in that post-tetanic count will be required to quantify deep block, and quantitative monitoring of recovery may be driven by cost concerns in order to allow the use of the smallest dose of sugammadex that gives a satisfactory train-of-four ratio. Alternatively, monitoring may essentially be abandoned since a large dose of sugammadex will reliably reverse any degree of rocuronium-induced block. The ultimate clinical utility of sugammadex will be clear only after large-scale clinical use.
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Affiliation(s)
- J E Caldwell
- Department of Anesthesia and Perioperative Medicine, University of California, San Francisco, CA, USA.
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Abstract
Administration of a nondepolarizing neuromuscular blocking drug (muscle relaxant) is a standard practice in many anesthetic scenarios. These muscle relaxants work by competitive antagonism of the neurotransmitter acetylcholine at nicotinic cholinergic receptors within the neuromuscular junction of skeletal muscle (Martyn et al; Neuromuscular physiology and pharmacology, anesthesia. Edited by RD Miller, Philadelphia, Churchill Livingstone, 2000). At the conclusion of the procedure for which the muscle relaxant was administrated, there will be a greater or lesser degree of residual muscle weakness. It is usually necessary to pharmacologically reverse this residual weakness to restore full function to the patient's muscles. Indeed, failure to reverse neuromuscular block is associated with increased perioperative morbidity and mortality (Arbous et al; Impact of anesthesia management characteristics on severe morbidity and mortality. Anesthesiology 2005;102:257-268; quiz 491-2). Pharmacologic reversal currently relies on the administration of an anticholinesterase drug, which decreases the metabolism of acetylcholine at the neuromuscular junction and allows its concentration to increase and hopefully overcome the effect of the muscle relaxant. This approach to reversal has significant limitations; the mechanism of reversal is indirect, the efficacy is limited and unpredictable, and undesirable autonomic responses occur. This review will address these limitations.
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Affiliation(s)
- James E Caldwell
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, CA 94143-0648, USA.
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Muravchick S, Caldwell JE, Epstein RH, Galati M, Levy WJ, O'Reilly M, Plagenhoef JS, Rehman M, Reich DL, Vigoda MM. Anesthesia Information Management System Implementation: A Practical Guide. Anesth Analg 2008; 107:1598-608. [DOI: 10.1213/ane.0b013e318187bc8f] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Abou-Arab MH, Heier T, Caldwell JE. Dose of alfentanil needed to obtain optimal intubation conditions during rapid-sequence induction of anaesthesia with thiopentone and rocuronium. Br J Anaesth 2007; 98:604-10. [PMID: 17403707 DOI: 10.1093/bja/aem064] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The primary aim of the present study was to determine the dose of alfentanil that must be added to a rapid-sequence induction (RSI) regimen using thiopentone and rocuronium to obtain optimal intubation conditions in >95% of the individuals. METHODS A total of 60 ASA I patients were randomly allocated to five different alfentanil dose groups (0, 15, 30, 45, or 60 microg kg-1). A blinded dose of alfentanil followed by thiopentone 4 mg kg-1 and rocuronium 1 mg kg-1 was administered in rapid succession, and tracheal intubation was attempted 40 s thereafter. The relationship between the alfentanil dose and the probability of optimal intubation conditions was determined by non-linear logistic regression analysis. Blood pressure (BP) changes were recorded continuously using an intra-arterial catheter. RESULTS The success rate of optimal intubation conditions increased with increasing doses of alfentanil. The alfentanil dose needed to obtain optimal intubation conditions in >95% of the patients was 36.4 (CI 33.4-39.4) microg kg-1. In 12 patients, the systolic BP declined to <90 mm Hg during the 3 min immediately after intubation. CONCLUSION Adding 36-40 microg kg-1 alfentanil to a regimen of thiopentone and rocuronium during RSI of anaesthesia may significantly increase the success rate of optimal intubation conditions. Significant hypotension requiring vasopressor treatment may occur.
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Affiliation(s)
- M H Abou-Arab
- Department of Anesthesia, Aker University Hospital, Oslo, Norway
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6
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Abstract
Muscle strength is reduced during hypothermia, both in the presence and in the absence of neuromuscular blocking drugs. A 2 degrees C reduction in body temperature may double the duration of neuromuscular blockade. Central body and muscle temperatures decline in parallel, as long as peripheral vasoconstriction does not occur. A reduction in muscle strength must be expected at a body temperature less than 36 degrees C (corresponding to a muscle temperature of approximately 35 degrees C). Local cooling of the hand may make adductor pollicis twitch tension monitoring less useful during clinical anesthesia. The efficacy of neostigmine is maintained during mild hypothermia. The use of a nerve stimulator is strongly recommended to monitor the effect of neuromuscular blocking drugs during intraoperative hypothermia.
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Affiliation(s)
- Tom Heier
- Department of Anesthesia, Aker University Hospital, Oslo, Norway.
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Wright PMC, McCarthy G, Szenohradszky J, Sharma ML, Caldwell JE. Influence of chronic phenytoin administration on the pharmacokinetics and pharmacodynamics of vecuronium. Anesthesiology 2004; 100:626-33. [PMID: 15108978 DOI: 10.1097/00000542-200403000-00024] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND The duration of action of vecuronium is reduced in patients receiving phenytoin. In this study, the authors examined, simultaneously, the influence of phenytoin on both the pharmacokinetics and the pharmacodynamics of vecuronium. METHODS This study was approved by the institutional review board of the University of California, San Francisco, and patients gave written informed consent. Twenty-two patients, 11 taking phenytoin and all scheduled to undergo prolonged neurosurgical procedures with general anesthesia, participated in the study. In 12 patients (6 phenytoin, 6 control), vecuronium was infused at 7.5 microg x kg(-1) x min(-1) until the first response (T1) of each train-of-four decreased by 50%; in the remaining 10 patients (5 phenytoin, 5 control), 200 microg/kg vecuronium was infused over 10 min. Arterial blood samples were drawn at intervals over the next 5-7 h. Plasma concentrations of vecuronium and 3-desacetylvecuronium were measured by capillary gas chromatography. Pharmacokinetic and pharmacodynamic modeling was used to characterize the disposition of vecuronium and patient responses to it in the two groups. RESULTS Clearance was typically increased by 138% (95% confidence interval, 93-183%) in patients taking phenytoin. The effect of vecuronium was well described using a sigmoid Emax model. The concentration of vecuronium giving 50% twitch depression was increased 124% (45-202%) in patients taking phenytoin. CONCLUSIONS Chronic phenytoin therapy reduces the effect of vecuronium by mechanisms that include both increased vecuronium metabolism and reduced sensitivity of the patient to circulating concentrations of vecuronium.
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Affiliation(s)
- Peter M C Wright
- Department of Anaesthesia and Perioperative Care, University of California, San Francisco, 94143-0648, USA.
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Talke P, Caldwell JE, Brown R, Dodson B, Howley J, Richardson CA. A comparison of three anesthetic techniques in patients undergoing craniotomy for supratentorial intracranial surgery. Anesth Analg 2002; 95:430-5, table of contents. [PMID: 12145066 DOI: 10.1097/00000539-200208000-00036] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
UNLABELLED Several anesthetic techniques have been used successfully to provide anesthesia for resection of intracranial supratentorial mass lesions. One technique used to enhance recovery involves changing anesthesia from vapor-based to propofol-based for cranial closure. However, there are no data to support a beneficial effect of this approach in the immediate postoperative period after craniotomy. We evaluated 3 anesthetic techniques in 60 patients undergoing elective surgery for supratentorial mass lesions. Patients were randomly assigned to three anesthesia study groups: propofol infusion, isoflurane inhalation, and these two techniques combined. In the combination group, once the dura was closed, isoflurane was discontinued and propofol infusion simultaneously started. We studied intra- and postoperative hemodynamics and several recovery variables for 2 h after the end of anesthesia. Baseline and average intraoperative blood pressure and heart rate values did not differ among the groups. Heart rate and blood pressure increased similarly in all groups in response to intubation and pin placement and postoperatively. None of the recovery event times (open eyes, extubation, follow commands, oriented, Aldrete score) or psychomotor test performance differed significantly. We conclude that the sequential administration of isoflurane and propofol did not provide earlier recovery and cognition than the intraoperative use of isoflurane alone. IMPLICATIONS We evaluated three anesthetic techniques with and without propofol in patients undergoing elective surgery for supratentorial mass lesions by using a prospective, randomized clinical study design and found that the three anesthetics did not differ in intra- or postoperative hemodynamic stability or early postoperative recovery variables.
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Affiliation(s)
- Pekka Talke
- Department of Anesthesia and Perioperative Medicine, University of California, San Francisco, California 94143, USA.
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Heier T, Clough D, Wright PMC, Sharma ML, Sessler DI, Caldwell JE. The influence of mild hypothermia on the pharmacokinetics and time course of action of neostigmine in anesthetized volunteers. Anesthesiology 2002; 97:90-5. [PMID: 12131108 DOI: 10.1097/00000542-200207000-00013] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND The pharmacokinetics, maximum effect, and time course of action of neostigmine were studied in seven human volunteers. METHODS Each volunteer was studied twice, during both normothermia and hypothermia. Anesthesia was induced with 30 microg/kg alfentanil and 3 mg/kg propofol, and was maintained with 60-70% nitrous oxide and 0.7-0.9% isoflurane. The mechanical response of the adductor pollicis to train-of-four stimulation of the ulnar nerve was recorded, and central body temperature maintained stable at either less than 34.5 degrees C or greater than 36.5 degrees C by surface cooling or warming. Before neostigmine administration, a stable 5% twitch height was obtained by an infusion of vecuronium, and the infusion rate remained unchanged thereafter. Neostigmine, 70 microg/kg, was then infused over 2 min, and blood samples for estimation of neostigmine concentrations were collected at intervals for 240 min. RESULTS With hypothermia, the central volume of distribution of neostigmine decreased by 38%, and onset time of maximum effect increased (4.6 vs. 5.6 min). Hypothermia did not change the clearance (696 ml/min), maximum effect, or duration of action of neostigmine. CONCLUSIONS The efficacy of neostigmine as an antagonist of vecuronium-induced neuromuscular block is not altered by mild hypothermia.
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Affiliation(s)
- Tom Heier
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, California 94143-0648, USA
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Greif R, Greenwald S, Schweitzer E, Laciny S, Rajek A, Caldwell JE, Sessler DI. Muscle relaxation does not alter hypnotic level during propofol anesthesia. Anesth Analg 2002; 94:604-8; table of contents. [PMID: 11867383 DOI: 10.1097/00000539-200203000-00023] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
UNLABELLED Electromyographic (EMG) activity can contaminate electroencephalographic signals. Paralysis may therefore reduce the Bispectral Index (BIS) by alleviating artifact from muscles lying near the electrodes. Paralysis may also reduce signals from muscle stretch receptors that normally contribute to arousal. We therefore tested the hypothesis that nondepolarizing neuromuscular block reduces BIS. Ten volunteers were anesthetized with propofol at a target effect site concentration of 3.8 plus/minus 0.4 microg/mL. A mivacurium infusion was adjusted to vary the first twitch (T1) in a train-of-four to 80%, 30%, 20%, 15%, 10%, 5%, or 2% of the prerelaxant intensity. At each randomly assigned T1, we measured BIS and frontal-temporal EMG intensity. BIS averaged 95 plus/minus 4 before induction of anesthesia, and decreased significantly to 40 plus/minus 5 after propofol administration. However, there were no significant differences at the designated block levels. Frontal-temporal EMG intensity averaged 47 plus/minus 3 dB before induction of anesthesia, and decreased significantly to 27 plus/minus 1 dB after propofol administration. However, there were no significant differences at the designated block levels. These data suggest that the BIS level and EMG tone are unaltered by mivacurium administration during propofol anesthesia. IMPLICATIONS Neuromuscular block level did not alter Bispectral Index (BIS) during propofol anesthesia, either by reducing electromyographic artifact or by decreasing afferent neuronal input. The BIS will thus comparably estimate sedation in deeply unconscious patients who are paralyzed, partially paralyzed, or unparalyzed.
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Affiliation(s)
- Robert Greif
- Department of Anesthesiology and Intensive Care Medicine, Donauspital-SMZO, Vienna, Austria
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Abstract
BACKGROUND Because tactile evaluation is the most common form of clinical neuromuscular monitoring, this study examines the relative efficacy of antagonizing residual block at different levels of recovery of the tactile train-of-four (TOF) response. METHODS Anesthesia was induced in 64 adults with 2-5 microg/kg fentanyl and 1-3 mg/kg propofol and maintained with fentanyl, propofol, and nitrous oxide. The tactile response of the adductor pollicis to TOF stimulation was evaluated at one arm, and the mechanomyographic response was recorded at the other. Patients received 0.15 mg/kg cisatracurium and were randomized to receive 0.07 mg/kg neostigmine on reappearance of the first (group I), second (group II), third (group III), or fourth (group IV) tactile TOF response (16 patients per group). Times from administration of neostigmine until the TOF ratio recovered to 0.7 (R0.7), 0.8 (R0.8), and 0.9 (R0.9) were measured. RESULTS Data are presented as median with range in parentheses. R0.7 was 10.3 (5.9-23.4), 7.6 (3.2-14.1), 5.0 (2.0-18.4), and 4.1 (2.4-11.0) min in groups I, II, III, and IV, respectively (P < 0.05, group I > II, III, and IV, group II > IV). R0.8 was 16.6 (8.9-30.7), 9.8 (5.3-25.0), 8.3 (3.8-27.1), and 7.5 (3.0-74.5) min in groups I, II, III, and IV, respectively (P < 0.05, group I > II, III, and IV, group II > IV). R0.9 was 22.2 (13.9-44.0), 20.2 (6.5-70.5), 17.1 (8.3-46.2), and 16.5 (6.5-143.3) min in groups I, II, III, and IV, respectively (no intergroup differences). Ten minutes after neostigmine, a TOF ratio of 0.7 or greater was achieved in 50, 75, 88, and 93% of patients in groups I, II, III, and IV, respectively (P < 0.05 group I > II, III, and IV). At 30 min, a TOF ratio of 0.9 or less was observed in 21, 13, 13, and 7% of patients in groups I, II, III, and IV respectively (no intergroup differences). CONCLUSIONS To achieve rapid (within 10 min) reversal to a TOF ratio of 0.7 in more than 87% of patients, three or four tactile responses should be present at the time of neostigmine administration. It was not possible within 30 min to achieve a TOF ratio of 0.9 in all patients, regardless of the number of tactile responses present at neostigmine administration.
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Affiliation(s)
- Hans Kirkegaard
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, USA.
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Heier T, Feiner JR, Lin J, Brown R, Caldwell JE. Hemoglobin desaturation after succinylcholine-induced apnea: a study of the recovery of spontaneous ventilation in healthy volunteers. Anesthesiology 2001; 94:754-9. [PMID: 11388524 DOI: 10.1097/00000542-200105000-00011] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Because of the rapid recovery of neuromuscular function after succinylcholine administration, there is a belief that patients will start breathing sufficiently rapidly to prevent significant oxygen desaturation. The authors tested whether this belief was valid. METHODS Twelve healthy volunteers aged 18-45 yr participated in the study. After preoxygenation to an end-tidal oxygen concentration greater than 90%, each subject received 5 mg/kg thiopental and 1 mg/kg succinylcholine. Oxygen saturation (SaO2) was measured at both a finger and an ear lobe (beat to beat). During the period of apnea and as they were recovering, the volunteers received continuous verbal reassurance by the investigators. If the SaO2 decreased below 80%, the volunteers received chin lift and, if necessary, assisted ventilation. The length of time the subject was apneic and level of desaturation were related by linear regression analysis. One hour after recovery and again 1 week later, subjects were asked a series of questions regarding their emotional experience. RESULTS In six volunteers, SaO2 decreased below 95% during apnea; in four, SaO2 decreased below 80%, necessitating chin lift and assisted ventilation in three. Apnea time was significantly longer in volunteers who reached SaO2 less than 80% than in those who did not (7.0+/-0.4 and 4.1+/-0.3 min, respectively), and there was a significant correlation between the length of time the subject was apneic and the magnitude of desaturation. CONCLUSIONS Spontaneous recovery from succinylcholine-induced apnea may not occur sufficiently quickly to prevent hemoglobin desaturation in subjects whose ventilation is not assisted.
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Kirkegaard-Nielsen H, Caldwell JE, Abengochea A, Berry PD, Heier T. Does discontinuation of desflurane at the time of neostigmine administration speed recovery from cisatracurium block compared to that with a propofol-based technique? Acta Anaesthesiol Scand 2001; 45:618-23. [PMID: 11309015 DOI: 10.1034/j.1399-6576.2001.045005618.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Volatile anaesthetics are known to influence the effect of neostigmine as an antagonist of neuromuscular block. The aim of the present study was to investigate whether discontinuation of desflurane at the time of neostigmine administration shortens reversal time from cisatracurium block, compared to that with a propofol-based anaesthesia. METHODS Ten volunteers were studied twice. For one study, anaesthesia was induced with alfentanil and propofol and maintained with nitrous oxide 70% and propofol 150 microg. kg-1. min-1. For the other study, experimental conditions were replicated except that desflurane 6% was administered and the dose of propofol was only 50 microg. kg-1. min-1. The evoked mechanical response of the adductor pollicis to train-of-four (TOF) stimulation was recorded. Neuromuscular block was induced with cisatracurium 0.2 mg. kg-1. When the magnitude of the first TOF response (T1) had recovered to 10%, the block was antagonized with neostigmine 70 microg. kg-1. At this time, propofol was decreased to 50 microg. kg-1. min-1, or the desflurane was discontinued. RESULTS There were no significant differences between the two techniques of anaesthesia in the rate of neostigmine-induced recovery of the TOF ratio. The times (mean+/-SD) to achieve TOF ratios of 0.7, 0.8, and 0.9 were (propofol first, desflurane second) 6.1+/-2.2 and 6.5+/-1.6 min; 10.4+/-4.2 and 9.6+/-2.7 min; 17.1+/-6.9 and 21.0+/-13.0 min, respectively. CONCLUSION Discontinuing desflurane does not speed neostigmine-induced recovery from cisatracurium neuromuscular block, when compared to that during propofol-based anaesthesia.
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Affiliation(s)
- H Kirkegaard-Nielsen
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, CA, USA.
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Abstract
Large concentrations of alpha(2) agonists cause vasoconstriction. However, the threshold of the vasoconstrictive effect in humans is not known. We studied seven volunteers to determine the lower limit of the vasoconstrictive effect of clonidine. Subjects were studied while they were awake, and they were anesthetized with propofol/alfentanil/N(2)O. Arterial blood pressure was continuously monitored via radial arterial catheter and vasoconstriction via finger volume plethysmography measuring infrared light transmitted through a fingertip (LTF). Clonidine was administered, targeting plasma clonidine concentrations of 0.3, 0.45, 0.68, 1.0, 1.5, and 2.25 ng/mL. The maximum change from preclonidine values for systolic blood pressure (SBP) and LTF was analyzed by using repeated measures analysis of variance. In awake subjects, clonidine (2.25 ng/mL) decreased LTF by 14%+/-13% and SBP from 141+/-7 to 110+/-15 mm Hg (P<0.0001). In contrast, clonidine (2.25 ng/mL) increased LTF in anesthetized subjects by 21%+/-16% and SBP from 91+/-7 to 106+/-19 mm Hg (P<0.0001). We conclude that the same dose of clonidine that decreased blood pressure and caused vasodilation in awake subjects had the opposite effect in anesthetized subjects with reduced sympathetic tone, increasing blood pressure and causing vasoconstriction in human digital vasculature. Our findings suggest that the lower threshold for clonidine-induced vasoconstriction in human digital vasculature is 1.0 ng/mL.
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Affiliation(s)
- P O Talke
- Department of Anesthesia and Perioperative Medicine, University of California, San Francisco, California 94143-0648, USA.
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16
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Abstract
UNLABELLED There are situations in anesthesia in which it may be desirable to achieve rapid tracheal intubation with perfect conditions, i.e., no coughing or straining. To determine the dose of rocuronium that gives a high probability of achieving perfect conditions for rapid (within 60 s) tracheal intubation, we administered a range of doses of rocuronium, some larger than used previously. Sixty adults, anesthetized with thiopental 4 mg/kg IV and alfentanil 10 microg/kg IV, received rocuronium 0.4 to 2.0 mg/kg IV. We used logistic regression to define the relationship of rocuronium dose to probability of achieving perfect intubation conditions. We estimated the doses giving 90% and 95% probability of achieving perfect intubation and used resampling to determine confidence limits for these estimates. Rocuronium 1.85 and 2.33 mg/kg gave, respectively, 90% and 95% probability of perfect intubation conditions. The confidence limits (5th and 95th percentile) for these estimates were 1.15 to 2.31 and 1.23 to 3.22 mg/kg, respectively. In conclusion, it is possible to achieve perfect intubation conditions with large doses of rocuronium, but the long duration of action and expense may limit the usefulness of the technique. IMPLICATIONS We found that it is possible to have a 90% probability of achieving perfect conditions for rapid tracheal intubation with large (up to 2.0 mg/kg) doses of rocuronium. These large doses of rocuronium may be useful in, for instance, head trauma or open globe injuries if succinylcholine is contraindicated.
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Affiliation(s)
- T Heier
- Ullevaal University Hospital, Oslo, Norway
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Caldwell JE, Heier T, Wright PM, Lin S, McCarthy G, Szenohradszky J, Sharma ML, Hing JP, Schroeder M, Sessler DI. Temperature-dependent pharmacokinetics and pharmacodynamics of vecuronium. Anesthesiology 2000; 92:84-93. [PMID: 10638903 DOI: 10.1097/00000542-200001000-00018] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND The authors evaluated the influence of temperature on the pharmacokinetics and pharmacodynamics of vecuronium because mild core hypothermia doubles its duration of action. METHODS Anesthesia was induced with alfentanil and propofol and maintained with nitrous oxide and isoflurane in 12 healthy volunteers. Train-of-four stimuli were applied to the ulnar nerve, and the mechanical response of the adductor pollicis was measured. Volunteers were actively cooled or warmed until their distal esophageal temperatures were in one of four ranges: < 35.0 degrees C, 35.0-35.9 degrees C, 36.0-36.9 degrees C, and > or = 37.0 degrees C. With temperature stabilized, vecuronium was infused at 5 microg x kg(-1) x min(-1) until the first response of each train-of-four had decreased by 70%. Arterial blood (for vecuronium analysis) was sampled at intervals until the first response recovered to at least 90% of its prevecuronium level. Vecuronium, 20 microg x kg(-1) x min(-1), was then infused for 10 min, and arterial blood was sampled at intervals for up to 7 h. Population-based nonlinear mixed-effects modeling was used to examine the effect of physical characteristics and core temperature on vecuronium pharmacokinetics and pharmacodynamics. RESULTS Decreasing core temperature over 38.0-34.0 degrees C decreases the plasma clearance of vecuronium (11.3% per degrees C), decreases the rate constant for drug equilibration between plasma and effect site (0.023 min(-1) per degrees C), and increases the slope of the concentration-response relationship (0.43 per degrees C). CONCLUSIONS Our results show that reduced clearance and rate of effect site equilibration explain the increased duration of action of vecuronium with reducing core temperature. Tissue sensitivity to vecuronium is not influenced by core temperature.
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Affiliation(s)
- J E Caldwell
- Department of Anesthesia and Perioperative Care, University of California-San Francisco, 94143-0648, USA.
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Fleming NW, Chung F, Glass PS, Kitts JB, Kirkegaard-Nielsen H, Gronert GA, Chan V, Gan TJ, Cicutti N, Caldwell JE. Comparison of the intubation conditions provided by rapacuronium (ORG 9487) or succinylcholine in humans during anesthesia with fentanyl and propofol. Anesthesiology 1999; 91:1311-7. [PMID: 10551582 DOI: 10.1097/00000542-199911000-00023] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Currently, the only approved muscle relaxant with a rapid onset and short duration of action is succinylcholine, a drug with some undesirable effects. Rapacuronium is an investigational nondepolarizing relaxant that also has a rapid onset and short duration and consequently should be compared with succinylcholine in its ability to facilitate rapid tracheal intubation. METHODS This prospective, randomized clinical trial involved 336 patients. Anesthesia was induced with fentanyl and propofol and either 1.5 mg/kg rapacuronium or 1.0 mg/kg succinylcholine. The goal was to accomplish tracheal intubation by 60 s after administration of the neuromuscular blocking drug. Endotracheal intubation was performed, and conditions were graded by a blinded investigator. Recovery of neuromuscular function was assessed by electromyography. RESULTS Intubation conditions were evaluated in 236 patients. Intubation by 60 s after drug administration occurred in 100% of patients with rapacuronium and in 98% with succinylcholine. Intubation conditions were excellent or good in 87% of patients with rapacuronium and in 95% with succinylcholine (P < 0.05). The time (median and range) to the first recovery of the train-of-four response was 8.0 (2.8-20.0) min with rapacuronium and 5.7 (1.8-17.7) min with succinylcholine (P < 0.05). The overall incidence of adverse effects was similar with both drugs. CONCLUSIONS A 1.5-mg/kg dose of rapacuronium effectively facilitates rapid tracheal intubation. It can be considered a valid alternative to 1.0 mg/kg succinylcholine for this purpose.
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Affiliation(s)
- N W Fleming
- Department of Anesthesiology, University of California, Davis, USA
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Fisher DM, Reynolds KS, Schmith VD, Hsu J, Sokoll MD, Lennon RL, Caldwell JE. The Influence of Renal Function on the Pharmacokinetics and Pharmacodynamics and Simulated Time Course of Doxacurium. Anesth Analg 1999. [DOI: 10.1213/00000539-199909000-00049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Fisher DM, Reynolds KS, Schmith VD, Hsu J, Sokoll MD, Lennon RL, Caldwell JE. The influence of renal function on the pharmacokinetics and pharmacodynamics and simulated time course of doxacurium. Anesth Analg 1999; 89:786-95. [PMID: 10475326 DOI: 10.1097/00000539-199909000-00049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
UNLABELLED Doxacurium's clearance (C1) is markedly decreased in patients with renal failure undergoing kidney transplantation. However, no studies have determined the influence of renal function (as assessed by creatinine clearance [CrCl]) on its pharmacokinetics in patients without renal failure. We studied 53 patients aged 19-59 yr. During N2O/isoflurane anesthesia, doxacurium was infused over 10 min, plasma was sampled for up to 6 h, and twitch tension was measured. A three-compartment model was fit to plasma concentration data and an effect compartment model to twitch data. Mixed-effects modeling was used to determine the influence of covariates, including CrC1, on doxacurium's pharmacokinetic/pharmacodynamic parameters. Obesity decreased both doxacurium's Cl (1.1% per percent above ideal body weight [IBW]) and its neuromuscular junction sensitivity (0.4% per percent above IBW). Cl increased 0.6% per mL/min increase in CrCl. In addition, the rate constant for equilibration between plasma concentration and effect decreased 46% per 1% increase in isoflurane, central compartment volume decreased 86% per 1% increase in isoflurane concentration, and slow distributional Cl decreased 69% per mg/ 100 mL increase in serum albumin. Simulations showed that the latter two covariates influence the time course of bolus doxacurium administration minimally. Both obesity and renal dysfunction prolong doxacurium's recovery markedly. When dosing is based on IBW, effects of CrCl on neuromuscular recovery are smaller compared with dosing based on actual weight. Therefore, obese patients should be dosed based on IBW. No further dosage adjustment is necessary for patients with renal dysfunction; however, recovery will take longer in patients with moderate-to-severe renal dysfunction. IMPLICATIONS We examined the factors influencing doxacurium's pharmacokinetic and pharmacodynamic characteristics. Both creatinine clearance and obesity significantly influence its time course. The effect of obesity is minimized if patients are dosed based on ideal body weight.
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Affiliation(s)
- D M Fisher
- Department of Anesthesia, University of California San Francisco, 94143-0648, USA.
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Abstract
BACKGROUND Rapid tracheal intubation with rocuronium has not been studied using a probability-based approach. The authors aimed to predict doses of rocuronium giving 90% and 95% probability of in intubation within 60 s and to estimate their durations of action. METHODS After premedication with midazolam, 2 mg, anesthesia was induced in 80 subjects with fentanyl, 2 microg/kg, followed 3 min later by propofol, 2 mg/kg. Patients received randomly rocuronium, 0.0, 0.4, 0.8, or 1.2 mg/kg (n = 20/ dose). Laryngoscopy began 40 s later, aiming for intubation at 60 s, and conditions were graded perfect, acceptable, or unacceptable, with the first two conditions being successful intubation. Anesthesia was maintained with isoflurane 0.5-1.0% (end-tidal) and fentanyL Duration of action was time until reappearance of the first tactile train-of-four response. The dose versus fraction of patients with successful intubation was analyzed by logistic regression. Doses giving 90% and 95% (D90 and D95) probability of successful intubation were calculated. RESULTS intubation was successful in 7, 11, 18, and 19 patients in the 0.0, 0.4, 0.8, and 1.2 mg/kg groups, respectively. The D90 and D95 doses (95% confidence limits in parentheses) were 0.83 (0.59-1.03) and 1.04 (0.76-1.36) mg/kg, respectively. Estimated time until first tactile train-of-four response after D90 and D95 doses was 32 and 46 min, respectively. CONCLUSIONS After induction with fentanyl and propofol, rocuronium, 1.04 mg/kg gives 95% probability of successful intubation at 60 s.
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Affiliation(s)
- H Kirkegaard-Nielsen
- Department of Anesthesia and Perioperative Care, University of California, San Francisco 94143-0648, USA
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Talke P, Caldwell JE, Richardson CA. Sevoflurane increases lumbar cerebrospinal fluid pressure in normocapnic patients undergoing transsphenoidal hypophysectomy. Anesthesiology 1999; 91:127-30. [PMID: 10422937 DOI: 10.1097/00000542-199907000-00020] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The data on the effect of sevoflurane on intracranial pressure in humans are still limited and inconclusive. The authors hypothesized that sevoflurane would increase intracranial pressure as compared to propofoL METHODS: In 20 patients with no evidence of mass effect undergoing transsphenoidal hypophysectomy, anesthesia was induced with intravenous fentanyl and propofol and maintained with 70% nitrous oxide in oxygen and a continuous propofol infusion, 100 microg x kg(-1) x min(-1). The authors assigned patients to two groups randomized to receive only continued propofol infusion (n = 10) or sevoflurane (n = 10) for 20 min. During the 20-min study period, each patient in the sevoflurane group received, in random order, two concentrations (0.5 times the minimum alveolar concentration [MAC] and 1.0 MAC end-tidal) of sevoflurane for 10 min each. The authors continuously monitored lumbar cerebrospinal fluid (CSF) pressure, blood pressure, heart rate, and anesthetic concentrations. RESULTS Lumbar CSF pressure increased by 2+/-2 mmHg (mean+/-SD) with both 0.5 MAC and 1 MAC of sevoflurane. Cerebral perfusion pressure decreased by 11+/-5 mmHg with 0.5 MAC and by 15+/-4 mmHg with 1.0 MAC of sevoflurane. Systolic blood pressure decreased with both concentrations of sevoflurane. To maintain blood pressure within predetermined limits (within+/-20% of baseline value), phenylephrine was administered to 5 of 10 patients in the sevoflurane group (range = 50-300 microg) and no patients in the propofol group. Lumbar CSF pressure, cerebral perfusion pressure, and systolic blood pressure did not change in the propofol group. CONCLUSIONS Sevoflurane, at 0.5 and 1.0 MAC, increases lumbar CSF pressure. The changes produced by 1.0 MAC sevoflurane did not differ from those observed in a previous study with 1.0 MAC isoflurane or desflurane.
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Affiliation(s)
- P Talke
- Department of Anesthesia, University of California, San Francisco, 94143-0648, USA.
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Abstract
UNLABELLED The neuromuscular effects of dexmedetomidine in humans are unknown. We evaluated the effect of dexmedetomidine on neuromuscular block and hemodynamics during propofol/alfentanil anesthesia. During propofol/alfentanil anesthesia, the rocuronium infusion rate was adjusted in 10 volunteers to maintain a stable first response (T1) in the train-of-four sequence at 50% +/- 3% of the pre-rocuronium value. Dexmedetomidine was then administered by computer-controlled infusion, targeting a plasma dexmedetomidine concentration of 0.6 ng/mL for 45 min. The evoked mechanical responses of the adductor pollicis responses (T1 response and T4/T1 ratio), systolic blood pressure (SBP), heart rate (HR), and transmitted light through a fingertip were measured during the dexmedetomidine infusion and compared with predexmedetomidine values using repeated-measures analysis of variance and Dunnett's test. Plasma dexmedetomidine levels ranged from 0.68 to 1.24 ng/mL. T1 values decreased during the infusion, from 51% +/- 2% to 44% +/- 9% (P < 0.0001). T4/T1 values did not change during the infusion. Plasma rocuronium concentrations increased during the infusion (P = 0.02). Dexmedetomidine increased SBP (P < 0.001) and decreased HR (P < 0.001) (5-min median values) during the infusion compared with values before the infusion. Dexmedetomidine increased the transmitted light through the fingertip by up to 41% +/- 8% during the dexmedetomidine infusion (P < 0.001).We demonstrated that dexmedetomidine (0.98 +/- 0.01 microg/kg) increased the plasma rocuronium concentration, decreased T1, increased SBP, and decreased finger blood flow during propofol/alfentanil anesthesia. We conclude that dexmedetomidine-induced vasoconstriction may alter the pharmacokinetics of rocuronium. IMPLICATIONS We studied the effect of an alpha2-agonist (dexmedetomidine) on rocuronium-induced neuromuscular block during propofol/alfentanil anesthesia. We found that the rocuronium concentration increased and the T1 response decreased during the dexmedetomidine administration. Although these effects were statistically significant, it is unlikely that they are of clinical significance.
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Affiliation(s)
- P O Talke
- Department of Anesthesia, University of California, San Francisco 94143-0648, USA.
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Talke PO, Caldwell JE, Richardson CA, Kirkegaard-Nielsen H, Stafford M. The Effects of Dexmedetomidine on Neuromuscular Blockade in Human Volunteers. Anesth Analg 1999. [DOI: 10.1213/00000539-199903000-00031] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Szenohradszky J, Caldwell JE, Wright PM, Brown R, Lau M, Luks AM, Fisher DM. Influence of renal failure on the pharmacokinetics and neuromuscular effects of a single dose of rapacuronium bromide. Anesthesiology 1999; 90:24-35. [PMID: 9915309 DOI: 10.1097/00000542-199901000-00006] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Because renal function affects the elimination of muscle relaxants, each new muscle relaxant must be evaluated in patients with renal failure. Accordingly, the neuromuscular effects and pharmacokinetics of rapacuronium were identified in patients with renal failure. METHODS Rapacuronium (1.5 mg/kg) was administered to 10 healthy volunteers and 10 patients with renal failure who were undergoing non-transplant surgery, were 18-45 yr old, and were anesthetized with propofol. The adductor pollicis muscle twitch tension was monitored. Plasma samples were obtained frequently for a period of 8 h to measure the concentrations of ORG9487 and its metabolite, ORG9488. Pharmacokinetic parameters were determined using mixed-effects modeling. RESULTS One patient was excluded from analysis because he was taking phenytoin chronically. Twitch depression at 1 min was less in patients than in healthy volunteers (median values: 92% in patients, 99% in volunteers). The times to 90% and peak twitch depression; to 10%, 25%, and 75% twitch recovery; and to 70% and 80% train-of-four ratios were similar in volunteers and patients. Rapacuronium's clearance was 32% less in patients with renal failure; in both groups, clearance decreased 0.909% per year of age compared with the value in a 30 yr old. The steady state distribution volume was 14% less in women than in men and 16% less in patients than in volunteers. For ORG9488, clearance was 85% less in patients than in volunteers. CONCLUSIONS The neuromuscular effects of a single dose of rapacuronium are affected minimally by renal failure. However, the decreased clearance of rapacuronium and its potent metabolite in renal failure suggests that repeated dosing of rapacuronium may lead to prolonged effects in patients with renal failure.
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Affiliation(s)
- J Szenohradszky
- Department of Anesthesia, University of California, San Francisco, USA
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Segredo V, Caldwell JE, Wright PM, Sharma ML, Gruenke LD, Miller RD. Do the pharmacokinetics of vecuronium change during prolonged administration in critically ill patients? Br J Anaesth 1998; 80:715-9. [PMID: 9771295 DOI: 10.1093/bja/80.6.715] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Neuromuscular blocking drugs may be administered over several days to patients in the intensive care unit (ICU), but their pharmacokinetics have been studied at only one point in time, or assumed to be constant throughout the period of administration. We sought to determine if, in individual patients, the pharmacokinetics of vecuronium changed over the course of its administration in the ICU. In six critically ill patients, we measured plasma vecuronium concentrations during two periods: first, during initial administration of vecuronium and second, after its administration continuously for 3-6 days. A pharmacokinetic model was fitted to these plasma concentration data, and its parameters permitted to vary between the periods to determine if they had altered. Individual clearance values during the study ranged from 1.4 to 4.4 ml kg-1 min-1. During prolonged administration, vecuronium clearance increased in three and decreased in two patients. This change ranged from a 61% decrease to a 58% increase, and was not linked to any clinical factor. The steady-state volume of distribution (range 368-1765 ml kg-1; median 494 ml kg-1) did not change in any patient during the study. The change in clearance of vecuronium during its prolonged administration in critically ill patients suggests that future studies of neuromuscular blocking drugs in the ICU should take account of their changing pharmacokinetics over the course of administration.
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Affiliation(s)
- V Segredo
- Department of Anesthesia, University of California, San Francisco 94143-0648, USA
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Caldwell JE, Abildgaard F, Dzakula Z, Ming D, Hellekant G, Markley JL. Solution structure of the thermostable sweet-tasting protein brazzein. Nat Struct Biol 1998; 5:427-31. [PMID: 9628478 DOI: 10.1038/nsb0698-427] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The fruit of Pentadiplandra brazzeana Baillon contains a small, sweet-tasting protein named brazzein. The structure of brazzein in solution was determined by proton nuclear magnetic resonance spectroscopy at pH 5.2 and 22 degrees C. The brazzein fold, which contains one alpha-helix and three strands of antiparallel beta-sheet, does not resemble that of either of the other two sweet-tasting proteins with known structures, monellin and thaumatin. Instead, the structure of brazzein resembles those of plant gamma-thionins and defensins and arthropod toxins. Sequence comparisons predict that members of a newly-identified family of serine proteinase inhibitors share the brazzein fold.
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Affiliation(s)
- J E Caldwell
- Graduate Program in Biophysics, University of Wisconsin-Madison 53706, USA
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Caldwell JE, Abildgaard F, Ming D, Hellekant G, Markley JL. Complete 1H and partial 13C resonance assignments at 37 and 22 degrees C for brazzein, an intensely sweet protein. J Biomol NMR 1998; 11:231-232. [PMID: 9679299 DOI: 10.1023/a:1008262104643] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- J E Caldwell
- Graduation Program in Biophysics, University of Wisconsin-Madison 53706, USA
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Lee HW, Caldwell JE, Dodson B, Talke P, Howley J. The effect of clonidine on cerebral blood flow velocity, carbon dioxide cerebral vasoreactivity, and response to increased arterial pressure in human volunteers. Anesthesiology 1997; 87:553-8. [PMID: 9316960 DOI: 10.1097/00000542-199709000-00015] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Because patients may be taking clonidine chronically or may be receiving it as a premedication before surgery, the authors investigated its effect on cerebral hemodynamics. METHODS In nine volunteers, middle cerebral artery mean blood flow velocity (Vm) was measured using transcranial Doppler ultrasonography (TCD). CO2 vasoreactivity was measured before clonidine administration (preclonidine), 90 min after clonidine, 5 microg/kg orally, then following restoration of mean arterial pressure (MAP) to the preclonidine level. In addition, Vm was measured after a phenylephrine-induced 30-mmHg increase in MAP. RESULTS After clonidine administration, Vm decreased from 62 +/- 9 to 48 +/- 8 cm/s (P < 0.01), and MAP decreased from 86 +/- 10 to 63 +/- 5 mmHg (P < 0.01; mean +/- SD). Clonidine decreased the CO2 vasoreactivity slope from 2.2 +/- 0.4 to 1.2 +/- 0.5 cm x s(-1) x mmHg(-1) (P < 0.05); restoring MAP to the preclonidine level increased the slope to 1.60 +/- 0.5 cm x s(-1) x mmHg(-1), still less than the preclonidine slope (P < 0.05). CO2 vasoreactivity expressed as a percentage change in Vm, decreased after clonidine, 3.5 +/- 0.8 versus 2.4 +/- 0.8 %/mmHg (P < 0.05); this difference disappeared after restoration of MAP, 3.1 +/- 1.2 %/mmHg. With a 30-mmHg increase in MAP, Vm increased by 13% before and after clonidine (P < 0.05). CONCLUSIONS Clonidine, 5 microg/kg orally, decreases Vm and slightly attenuates cerebral CO2 vasoreactivity, therefore decreased cerebral blood flow and mildly attenuated CO2 vasoreactivity should be anticipated.
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Affiliation(s)
- H W Lee
- Department of Anesthesia, University of California, San Francisco 94143-0648, USA
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Lee HW, Caldwell JE, Wilson CB, Dodson B, Howley J. Venous bleeding during transsphenoidal surgery: its association with pre- and intraoperative factors and with cavernous sinus and central venous pressures. Anesth Analg 1997; 84:545-50. [PMID: 9052298 DOI: 10.1097/00000539-199703000-00014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Venous bleeding during transsphenoidal surgery for resection of pituitary tumors is a common problem that interferes with the performance of the surgical procedure. In this study, data were collected prospectively from 50 patients to determine whether there were pre- or intraoperative factors (e.g., patient demographics, type and grade of pituitary tumor, intraoperative hemodynamics) associated with venous bleeding which might be used to predict its occurrence. In addition, central venous pressure (CVP), and cavernous sinus pressure (CSP) were measured in 13 patients to evaluate the relationship of these pressures to each other and to the severity of venous bleeding. During resection of the pituitary tumor, the severity of venous bleeding was graded as minimal, moderate, or severe, the latter two grades requiring therapeutic intervention. Moderate bleeding requiring intervention occurred in 15 of the 50 patients, and resolved in all cases. Moderate bleeding was not related to CSP or CVP, and no specific associated factor was observed. CSP was not correlated with CVP, and was higher than that predicted from the CVP and the position of the patient or the hydrostatic gravitational pressure gradient. These results suggest that it is not possible to predict in advance which patients will have problems with venous bleeding, but that simple therapeutic maneuvers are effective.
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Affiliation(s)
- H W Lee
- Department of Anesthesia, University of California 94143-0648, USA
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Lee GC, Iyengar S, Szenohradszky J, Caldwell JE, Wright PM, Brown R, Lau M, Luks A, Fisher DM. Improving the design of muscle relaxant studies. Stabilization period and tetanic recruitment. Anesthesiology 1997; 86:48-54. [PMID: 9009939 DOI: 10.1097/00000542-199701000-00008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND The results from studies of muscle relaxants show wide variations among institutions. The authors hypothesized that some of this variability could be explained by differences in duration of nerve stimulation before drug administration (stabilization period). METHODS Train-of-four stimulation was applied every 12 s to both ulnar nerves and adductor pollicis twitch tension was measured in anesthetized participants given 30 micrograms/kg vecuronium. In phase 1, the stabilization period was > 30 min for both extremities. In phase 2-4, stabilization period was 20 min for one extremity and 2 min for the other. In addition, in phase 3, a 2-s 50-Hz tetanus initiated the 2-min stimulation period; in phase 4, duration of tetanus was 5 s. Twitch recovery was recorded until stable for more than 15 min. Time to 25% recovery (clinical duration) was calculated based on two indices: predrug and final (recovery) twitch tension. Values for onset and clinical duration were compared by paired parametric and nonparametric tests. RESULTS In phase 1, predrug and recovery twitch tension were similar in each extremity, and onset and clinical duration did not differ between extremities, permitting paired comparisons in remaining studies. In phase 2, onset was more rapid with 20-min of prestimulation. With 20-min prestimulation, predrug and recovery twitch tension were similar; with 2-min prestimulation, recovery twitch tension exceeded predrug values. When referenced to predrug twitch tension, clinical duration was shorter with 2-min, that with 20-min prestimulation. Initiating stimulation with 2-s or 5-s 50-Hz tetani (phases 3, 4) abolished differences between extremities in onset and recovery. CONCLUSIONS With only train-of-four stimulation (no tetani), onset and clinical duration vary with duration of prestimulation, suggesting that a brief period of predrug stimulation is inadequate. However, lengthy prestimulation may be impractical in clinical studies. Tetanic stimulation for 2 or 5 s obviates the need for prolonged stabilization during studies of muscle relaxants.
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Affiliation(s)
- G C Lee
- Department of Anesthesia, University of California, San Francisco 94143-0648, USA
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Abstract
BACKGROUND To determine which of atracurium or vecuronium is associated with fewer adverse cardiovascular and pulmonary events in high-risk patients, the authors administered these drugs to patients with known asthma. METHODS Sixty patients aged 18-75 yr taking bronchodilators chronically for asthma were anesthetized with midazolam, fentanyl, nitrous oxide, and isoflurane; the trachea was intubated without paralysis. When anesthetic conditions and mechanical ventilation were stable, patients were randomly given 0.5 mg/kg atracurium or 0.1 mg/kg vecuronium over 5-10 s, and a blinded observer recorded cardiovascular, pulmonary, and cutaneous signs of adverse reactions for 6 min. RESULTS Arterial pressures and heart rate decreased after atracurium, and systolic pressure and heart rate decreased with vecuronium; these changes were small in magnitude. Cardiovascular effects (decrease in blood pressure or change in heart rate) > 10% were common with both atracurium (60% of patients) and vecuronium (57%). Cardiovascular effects > 20% were more frequent with atracurium (37%) than with vecuronium (13%, P < 0.05). The incidence of noncardiovascular adverse events (increase in peak airway pressure > 5 cmH2O, tidal volume decrease > 10%, rashes, and wheezing) did not differ between atracurium (17%) and vecuronium (7%). The largest increase in peak airway pressure was 5.1 cmH2O in a patient whose tidal volume decreased 16% with vecuronium; in the remaining patients, tidal volume decreased < 10%. No patients experienced inspiratory wheezing, marked decreases in arterial oxygen saturation, or marked increases in end-tidal carbon dioxide tension. CONCLUSIONS The authors conclude that, in patients with asthma, adverse cardiovascular events are more common with atracurium than with vecuronium.
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Affiliation(s)
- J E Caldwell
- Department of Anesthesia, University of California, San Francisco 94143-0648, USA
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Abstract
The purpose of this study was to measure the degree of residual neuromuscular block at different times after a single dose of vecuronium, and to evaluate the effectiveness of two different doses of neostigmine in antagonizing this residual block. Train-of-four (TOF) ratios were examined for up to 4 h after a single dose of vecuronium, 0.1 mg/kg, in 60 patients during nitrous oxide/isoflurane/fentanyl anesthesia. The effect of neostigmine, 40 micrograms/kg, was studied at 1,2,3, or 4 h. The effect of neostigmine, 20 micrograms/kg, was studied at 2 or 4 h after the vecuronium. Before neostigmine administration, the TOF ratio was less than 0.75 in 17 patients (including one patient at 4 h). Neostigmine produced an increase in TOF ratio in 52 patients and a decrease in 8. The TOF ratio decreased after neostigmine only, at 2,3, or 4 h after vecuronium, when the TOF ratio was > or = 0.9 and when neostigmine 40 micrograms/kg was administered. One patient, at 1 h, had a TOF ratio of 0.00 and this did not reach 0.75 until 57 min after neostigmine, 40 micrograms/kg. There was a high incidence (50%) of adverse cardiovascular effects after both doses of neostigmine. In making the decision as to whether neostigmine should be administered, the risk to the patient of residual neuromuscular block must be balanced against the adverse cardiovascular effects of the neostigmine.
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Affiliation(s)
- J E Caldwell
- Department of Anesthesia, University of California, San Francisco 94143-0648, USA
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Caldwell JE. New muscle relaxants. West J Med 1995; 162:51-2. [PMID: 7863657 PMCID: PMC1022593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The Council on Scientific Affairs of the California Medical Association presents the following epitomes of progress in anesthesiology. Each item, in the judgment of a panel of knowledgeable physicians, has recently become reasonably firmly established, both as to scientific fact and clinical importance. The items are presented in simple epitome, and an authoritative reference, both to the item itself and to the subject as a whole, is generally given for those who may be unfamiliar with a particular item. The purpose is to assist busy practitioners, students, researchers, and scholars to stay abreast of progress in medicine, whether in their own field of special interest or another. The epitomes included here were selected by the Advisory Panel to the Section on Anesthesiology of the California Medical Association, and the summaries were prepared under the direction of Dr Jackson and the panel.
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Wright PM, Caldwell JE, Miller RD. Onset and duration of rocuronium and succinylcholine at the adductor pollicis and laryngeal adductor muscles in anesthetized humans. Anesthesiology 1994; 81:1110-5. [PMID: 7978469 DOI: 10.1097/00000542-199411000-00004] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Rocuronium, a new nondepolarizing muscle relaxant, has a rapid onset of activity and may be suitable as a component of a rapid-sequence induction of anesthesia. We evaluated a range of doses on onset and duration of effect at the larynx and the adductor pollicis and compared these characteristics with those of succinylcholine. METHODS Forty-eight patients aged 18-70 yr, of ASA physical status 1-3, were randomly allocated to receive succinylcholine (1 mg/kg) or one of three doses of rocuronium (0.4, 0.8, or 1.2 mg/kg) during surgery. Anesthesia was induced and maintained with propofol and fentanyl. The trachea was intubated without the use of muscle relaxants, and the cuff of the endotracheal tube placed between the vocal cords. Neuromuscular transmission was monitored by mechanomyography at the laryngeal adductor and adductor pollicis muscles. Muscular activity was evoked with supramaximal stimuli in a train-of-four sequence every 12 s to the anterior branch of the recurrent laryngeal nerve and the ulner nerve. RESULTS At the laryngeal adductors, peak effect exceeded 99% in all patients given succinylcholine and in none (0%), five (42%), and ten (83%) of those given rocuronium 0.4, 0.8, and 1.2 mg/kg, respectively. At the adductor pollicis, peak effect exceeded 99% in all study patients except two who received rocuronium 0.4 mg/kg (peak effects 91% and 97%). Onset of effect with succinylcholine was significantly more rapid at the laryngeal adductors (34 +/- 12 s, mean +/- SD) than at the adductor pollicis (56 +/- 15 s); this was true also for rocuronium 0.4 mg/kg (92 +/- 29 s and 155 +/- 40 s for the laryngeal adductors and adductor pollicis, respectively). Onset times were similar at the two muscle groups with rocuronium 0.8 and 1.2 mg.kg-1: 96 +/- 29 and 74 +/- 36 s with 0.8 mg/kg and 54 +/- 30 and 65 +/- 21 s with 1.2 mg/kg at the laryngeal adductors and the adductor pollicis, respectively. CONCLUSIONS The laryngeal adductors are more resistant to the action of rocuronium than is the adductor pollicis. Consequently, the onset of effect of rocuronium, in doses greater than 0.8 mg/kg, is similar to that of succinylcholine at the adductor pollicis but is significantly delayed compared with that of succinylcholine at the laryngeal adductors.
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Affiliation(s)
- P M Wright
- Department of Anesthesia, University of California, San Francisco 94143-0648
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Caldwell JE, Szenohradszky J, Segredo V, Wright PM, McLoughlin C, Sharma ML, Gruenke LD, Fisher DM, Miller RD. The pharmacodynamics and pharmacokinetics of the metabolite 3-desacetylvecuronium (ORG 7268) and its parent compound, vecuronium, in human volunteers. J Pharmacol Exp Ther 1994; 270:1216-22. [PMID: 7932174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The pharmacology of 3-desacetylvecuronium, the principal metabolite of vecuronium, was investigated. We studied 12 healthy volunteers, each on two occasions. First they received 3-desacetylvecuronium alone and then, on a later occasion, vecuronium. Six subjects received a large dose of each drug (pharmacokinetic study), the remaining six received a small dose (pharmacodynamic study). Drug concentrations in plasma and urine were measured using capillary gas chromatography. Neuromuscular block was assessed by measuring force of contraction of the adductor pollicis. Drug plasma concentration vs. time and neuromuscular effect data were analyzed by nonlinear mixed-effects modeling. 3-Desacetylvecuronium, compared with vecuronium (median, range in parentheses), had a smaller plasma clearance, 3.51 (2.11-6.57) vs. 5.39 (5.04-7.19) ml.kg-1.min-1; a larger steady-state distribution volume, 254 (215-410) vs. 152 (111-170) ml.kg-1; a longer terminal elimination half-life 116 (44-672) vs. 34 (25-61) min and a longer mean residence time, 67 (42-145) vs. 26 (18-32) min (P < .05). Renal clearances of 3-desacetylvecuronium and vecuronium were 0.85 (0.15-1.24) and 0.58 (0.16-0.66) ml.kg-1.min-1, respectively (P < .05). Conversion to 3-desacetylvecuronium accounted for 12% of vecuronium's clearance. Concentrations of 3-desacetylvecuronium and vecuronium that produced 50% neuromuscular block were 123 (109-154) and 102 (71-123) ng.ml-1, respectively (P < .05). 3-Desacetylvecuronium is a potent neuromuscular blocking drug and may be responsible for episodes of prolonged paralysis after long-term administration of vecuronium to patients in intensive care units.
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Affiliation(s)
- J E Caldwell
- Department of Anesthesia, University of California, San Francisco
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Abstract
We have examined postoperative muscle pain and early increases in serum concentrations of myoglobin after administration of suxamethonium to see if these changes were dependent on the dose of drug. Thirty ASA I and II adult patients undergoing day-case surgery received a standard anaesthetic technique, including one of three doses of suxamethonium: 0.5, 1.5 or 3.0 mg kg-1. The incidence of postoperative myalgia and the severity of fasciculations were greater after suxamethonium 1.5 mg kg-1 than after a dose of 0.5 or 3.0 mg kg-1. Serum concentrations of myoglobin increased in a dose-dependent manner. Intubating conditions were significantly better with suxamethonium 1.5 or 3.0 mg kg-1 than with 0.5 mg kg-1. Changes in serum concentrations of calcium and potassium were small and similar in the three groups. We conclude that a dose of 3.0 mg kg-1 of suxamethonium provided a better combination of intubating conditions and minimal postoperative myalgia than the two lower doses.
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Affiliation(s)
- C McLoughlin
- Department of Anesthesia, University of California, San Francisco 94143-0648
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Abstract
Desflurane is a new volatile anaesthetic agent, with qualitative physiological and pharmacological effects similar to those of previously available drugs of this type. The feature that sets desflurane apart from other halogenated, volatile anaesthetics is its low solubility in blood and body tissues. Therefore, its uptake, distribution and elimination are more rapid than those for similar drugs. Desflurane undergoes negligible metabolism, and should have a low potential for producing toxic effects. Because it has a high vapour pressure desflurane needs a special delivery system, a heated, pressurised vaporizer. Its low solubility gives it the ability to produce rapid alterations in depth of anaesthesia and rapid emergence and recovery from anaesthesia.
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Affiliation(s)
- J E Caldwell
- Department of Anesthesia, University of California, San Francisco
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Heier T, Caldwell JE, Sharma ML, Gruenke LD, Miller RD. Mild intraoperative hypothermia does not change the pharmacodynamics (concentration-effect relationship) of vecuronium in humans. Anesth Analg 1994; 78:973-7. [PMID: 7909212 DOI: 10.1213/00000539-199405000-00024] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
To investigate the effect of mild hypothermia on the neuromuscular junction sensitivity to vecuronium, we determined the pharmacodynamics (concentration-effect relationship) of vecuronium in 10 patients (ASA physical class I or II; age range, 21-46 yr; weight range, 54-104 kg), during isoflurane-nitrous oxide-fentanyl anesthesia. Five were cooled to a mean temperature of 34.4 degrees C and five were maintained normothermic at a mean temperature of 36.8 degrees C. Neuromuscular function was monitored by measuring the evoked mechanical response of the adductor pollicis muscle after supramaximal train-of-four stimulation of the ulnar nerve at the wrist. Vecuronium, 3 micrograms.kg-1.min-1, was infused for 10 min, venous blood sampled for 60 min, and twitch tension and plasma concentration data were used to determine pharmacodynamic variables in each patient. Results for the hypothermic and normothermic groups were compared by Mann-Whitney U-test. There were no differences in any pharmacodynamic variable between the hypothermic and normothermic patients. For the hypothermic and normothermic patients, respectively, steady-state plasma concentrations of vecuronium producing 50% neuromuscular block (Css50) were 73 +/- 13 ng/mL (mean +/- SD) and 79 +/- 31 ng/mL; the rate constants for equilibration of vecuronium between the plasma and the neuromuscular junction (Keo) were 0.27 +/- 0.14 per min-1 and 0.26 +/- 0.11 per min, and the power functions representing the slope of the concentration-effect relationship (gamma) were 5.7 +/- 1.9 and 4.4 +/- 1.8.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- T Heier
- Department of Anesthesia, University of California, San Francisco 94143-0648
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Szenohradszky J, Caldwell JE, Sharma ML, Gruenke LD, Miller RD. Interaction of rocuronium (ORG 9426) and phenytoin in a patient undergoing cadaver renal transplantation: a possible pharmacokinetic mechanism? Anesthesiology 1994; 80:1167-70. [PMID: 8017655 DOI: 10.1097/00000542-199405000-00028] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- J Szenohradszky
- Department of Anesthesia, University of California, San Francisco 94143-0648
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Chen L, Richardson JS, Caldwell JE, Ang LC. Regional brain activity of free radical defense enzymes in autopsy samples from patients with Alzheimer's disease and from nondemented controls. Int J Neurosci 1994; 75:83-90. [PMID: 8050854 DOI: 10.3109/00207459408986291] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Several lines of evidence support the hypothesis that oxygen free radicals are involved in the destruction of neurons in various degenerative disorders of the central nervous system. The activities of superoxide dismutase, catalase and glutathione peroxidase, three enzymes that contribute to the cellular defenses against free radical damage, were measured in different areas of autopsy brains from patients with Alzheimer's disease and from age matched controls. All brains were removed within 24 hours of the time of death and were cut in half sagitally. One half was stored frozen at -86 degrees C and the other half was examined histologically to confirm the presence or absence of Alzheimer's disease. Samples were taken from the frozen half for the enzyme assays. In control brains, the activity of superoxide dismutase is significantly higher in the cerebellum, frontal cortex and hippocampus than it is in the temporal cortex, parietal cortex and entorhinal cortex. The activity of catalase is significantly higher in cerebellum and frontal cortex than in hippocampus, parietal cortex and entorhinal cortex. Glutathione peroxidase activity is uniform across all brain areas studied. In Alzheimer's brains, superoxide dismutase activity is not statistically different among the various brain regions studied, but it is significantly lower than control in the cerebellum (-27%), frontal cortex (-27%) and hippocampus (-35%). Catalase is significantly higher in Alzheimer's cerebellum, frontal cortex and temporal cortex than in Alzheimer's hippocampus, parietal cortex and entorhinal cortex. However, there are no significant differences in catalase activity between Alzheimer's and control samples.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- L Chen
- Department of Pharmacology, College of Medicine, University of Saskatchewan, Saskatoon, Canada
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Heier T, Caldwell JE, Eriksson LI, Sessler DI, Miller RD. The effect of hypothermia on adductor pollicis twitch tension during continuous infusion of vecuronium in isoflurane-anesthetized humans. Anesth Analg 1994; 78:312-7. [PMID: 7906109 DOI: 10.1213/00000539-199402000-00019] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The effect of total body cooling on force of contraction of the adductor pollicis was determined during a constant rate infusion of vecuronium. Anesthesia was induced with thiopental and maintained with isoflurane/nitrous oxide in eight volunteers (study group) and seven surgical patients (control group). After train-of-four (TOF) stimulation of the ulnar nerve, we measured the amplitude of the first response (T1) in the train and the ratio of the fourth-to-first response (TOF ratio). Vecuronium was then administered as an intravenous (i.v.) bolus, 25 micrograms/kg, followed by continuous i.v. infusion, 25 micrograms.kg-1 x h-1; central body (core) temperature was maintained stable for 60 min, at the end of which T1 and TOF responses were constant. In the study group, core temperature was then reduced (using circulating-water blankets) by a mean of 2.6 degrees C, decreasing the T1 and TOF ratio, respectively, by 19% and 18% per degrees C reduction in adductor pollicis temperature. Normothermia was maintained in the control group for a mean of 111 min, with no significant change in T1 and TOF responses. We conclude that, during a constant-rate infusion of vecuronium, the magnitude of neuromuscular block increases significantly when adductor pollicis temperature decreases secondary to core cooling.
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Affiliation(s)
- T Heier
- Department of Anesthesia, University of California, San Francisco 94143-0648
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Szenohradszky J, Trevor AJ, Bickler P, Caldwell JE, Sharma ML, Rampil IJ, Miller RD. Central nervous system effects of intrathecal muscle relaxants in rats. Anesth Analg 1993; 76:1304-9. [PMID: 8098920 DOI: 10.1213/00000539-199306000-00020] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
When given for a sufficient time and dose intravenously, neuromuscular blocking drugs eventually can enter the cerebrospinal fluid (CSF). To study the potential pharmacologic consequences of neuromuscular blocking drugs in the CSF, a model was developed in the rat by using an intrathecal infusion of these drugs. A cannula was stereotaxically implanted in a lateral cerebral ventricle of anesthetized male Sprague-Dawley rats (250-300 g). Several days later, the effects of an intraventricular infusion (5 microL/min) of atracurium (0.804 mumol/mL), pancuronium (0.172 mumol/mL), and vecuronium (21.978 mumol/mL) were studied in unanesthetized rats. These rats (n = 6 in each group) exhibited dose-dependent hyperexcitability, during drug infusion, with seizures occurring at threshold doses of (mean), 0.12, 0.26, and 0.065 +/- 0.010 and 3.32 mumol/kg of atracurium, pancuronium, and vecuronium, respectively. The neuromuscular ED50 (intravenous dose required to produce a 50% depression of twitch tension) in rats determined by other investigators are 0.408, 0.115, and 0.352 mumol/kg for atracurium, pancuronium, and vecuronium, respectively. Therefore, seizure threshold doses were not related to the potencies of these drugs as neuromuscular blocking drugs. Based on these data, central nervous system effects were studied over the subseizure dose range approximating 1/100, 1/10, and 1/5 of the cumulative dose causing seizures for each drug (n = 5 for each dose). At 1/100 of seizure dose, decreased locomotor activity and piloerection occurred. At 1/10 to 1/5 of seizure dose, agitation, shivering, splayed limbs, and whole body shaking resulted.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J Szenohradszky
- Department of Anesthesiology, School of Medicine, University of California, San Francisco
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Szenohradszky J, Fisher DM, Segredo V, Caldwell JE, Bragg P, Sharma ML, Gruenke LD, Miller RD. Pharmacokinetics of rocuronium bromide (ORG 9426) in patients with normal renal function or patients undergoing cadaver renal transplantation. Anesthesiology 1992; 77:899-904. [PMID: 1443743 DOI: 10.1097/00000542-199211000-00010] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
To determine the effect of end-stage renal disease on the pharmacokinetics of reocuronium bromide (ORG 9426), a new nondepolarizing monoquaternary steroidal neuromuscular blocking drug, the authors administered 600 micrograms/kg rocuronium (2 x ED95) intravenously to ten patients undergoing cadaver renal transplantation and ten healthy patients undergoing elective minor surgery (controls). All patients were anesthetized with nitrous oxide (50-70% in oxygen) and isoflurane (end-tidal concentrations of 1.2 +/- 0.5% and 0.8 +/- 0.2%, mean +/- SD, for control and transplant groups, respectively). Plasma concentrations of rocuronium were determined by capillary gas chromatography. A population-based pharmacokinetic analysis (NONMEM) was used to determine typical values, standard errors, and interindividual variability for the pharmacokinetic parameters and to determine whether these values differed between control and renal transplant patients. Total plasma clearance (2.89 +/- 0.25 ml.kg-1.min-1, mean +/- SE) and volume of the central compartment (76.9 +/- 10.6 ml/kg) did not differ between control and renal transplant patients, whereas volume of distribution at steady state was greater in renal transplant patients (264 +/- 19 ml/kg) than in control patients (207 +/- 14 ml/kg). This resulted in a longer elimination half life in renal transplant patients (97.2 +/- 17.3 min) compared to controls (70.9 +/- 4.7 min). The authors conclude that renal failure and renal transplantation alter the distribution but not the clearance of rocuronium.
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Affiliation(s)
- J Szenohradszky
- Department of Anesthesia, University of California, San Francisco 94143-0648
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Langner CA, Lodge JK, Travis SJ, Caldwell JE, Lu T, Li Q, Bryant ML, Devadas B, Gokel GW, Kobayashi GS. 4-oxatetradecanoic acid is fungicidal for Cryptococcus neoformans and inhibits replication of human immunodeficiency virus I. J Biol Chem 1992; 267:17159-69. [PMID: 1512254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Candida albicans and Cryptococcus neoformans are major causes of systemic fungal infections, particularly in patients with acquired immunodeficiency syndrome. Metabolic labeling studies revealed that these organisms synthesize a small number of N-myristoylproteins, the most prominent being 20-kDa ADP-ribosylation factors (Arfs). C. albicans Arf has approximately 80% identity with the essential Arf1 and Arf2 proteins of Saccharomyces cerevisiae. [3H]Myristic acid analogs with oxygen for -CH2- substitutions at C4, C6, C11, and C13 are incorporated into cellular N-myristoylproteins, phospholipids, and neutral lipids produced by these three yeasts during exponential growth at 30 degrees C in complex media. Analog- and organism-specific differences in the efficiency of labeling of proteins and lipid classes were observed. The effects of oxatetradecanoic acids with oxygen for -CH2- substitutions at C3-C13 on C. neoformans, C. albicans, and S. cerevisiae were assessed during mid-log phase growth at 30 degrees C. A single dose of 3-oxa-, 4-oxa-, 5-oxa- or 6-oxatetradecanoic acid (O3-O6, final concentration = 300 microM) was able to inhibit growth of C. neoformans in the order O4 greater than O5 greater than O3 approximately O6. The other compounds were inactive. 4-Oxatetradecanoic acid was fungicidal, producing a 10,000-fold reduction in viable cell number 1 h after administration and continued suppression of cell growth for 7 h. A clear dose response was observed over a concentration range of 100-300 microM. 4-Oxatridecanoic acid was 100-fold less potent in reducing cell viability than 4-oxatetradecanoic acid but more potent than 5-oxatridecanoic acid. O4 produced approximately 10-100-fold reductions in the viability of C. albicans and S. cerevisiae at 300-500 microM, respectively, whereas O5 and O6 were less active. Since N-myristoylation of the Pr55gag polyprotein precursor produced by human immunodeficiency virus I (HIV-I) is essential for its assembly, we also assessed the antiviral effects of 4-oxatetradecanoic acid. O4 is able to produce a 50% reduction in the replication of HIV-I in acutely infected human T-lymphocyte cell lines at a concentration of 18 microM. Together, these data suggest that (i) the position of the oxygen for methylene substitution is a critical determinant of the fungicidal activity of O4 and (ii) NMT may be an attractive therapeutic target for treating opportunistic fungal infections in patients infected with HIV-I.
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Affiliation(s)
- C A Langner
- Department of Molecular Biology and Pharmacology, Washington University School of Medicine, St. Louis, Missouri 63110
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Abstract
BACKGROUND The muscle relaxant vecuronium is sometimes administered to facilitate mechanical ventilation. Neuromuscular paralysis lasting up to seven days may occur after the termination of long-term administration (i.e., more than two days) of vecuronium in critically ill patients. We investigated the role of clinical factors and plasma concentrations of vecuronium and its metabolite in causing this prolonged neuromuscular blockade. METHODS We studied 16 critically ill adult patients (8 women and 8 men) who had received vecuronium to facilitate mechanical ventilation for at least two consecutive days. Clinical factors and plasma concentrations of vecuronium and 3-desacetylvecuronium, the active metabolite of vecuronium, were compared in patients with and without prolonged neuromuscular blockade. In addition, we performed detailed pharmacokinetic studies in the patients without prolonged neuromuscular blockade. RESULTS Seven of the 16 patients had prolonged neuromuscular blockade, lasting from six hours to more than seven days, after the termination of vecuronium therapy. These seven patients, six of whom were women, had higher plasma magnesium concentrations and lower arterial blood pH values than the nine patients without prolonged neuromuscular blockade. They also had higher plasma concentrations of 3-desacetylvecuronium and a higher frequency of renal failure (seven of seven patients vs. four of nine patients, P less than 0.03). In the patients without prolonged neuromuscular blockade, the mean (+/- SD) plasma clearance, elimination half-life, and volume of distribution of vecuronium were 2.5 +/- 1.0 ml per kilogram of body weight per minute, 299 +/- 154 minutes, and 1.1 +/- 0.6 liters per kilogram, respectively. CONCLUSIONS Prolonged neuromuscular blockade after the termination of long-term treatment with vecuronium is associated with metabolic acidosis, elevated plasma magnesium concentrations, female sex, and probably more important, the presence of renal failure and high plasma concentrations of 3-desacetylvecuronium.
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Affiliation(s)
- V Segredo
- Department of Anesthesia, University of California, San Francisco 94143-0648
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