Biomedical subjects

J Ducharme

Publications and source records attributed to J Ducharme.

44 records · Page 3Linked to original sources

PubMed1991

Pharmacokinetics and pharmacodynamics of atracurium obtained with arterial and venous blood samples.

To determine the influence of sampling site on atracurium pharmacokinetic-pharmacodynamic relationships, blood was drawn simultaneously from the radial artery and peripheral vein during a 20-minute period after injection of atracurium, 0.2 mg/kg, in eight patients. Atracurium and laudanosine concentrations were measured by HPLC. Neuromuscular blockade was measured at the adductor pollicis, after stimulation of the ulnar nerve. Venous levels were lower than corresponding arterial values for up to 20 minutes, and this difference was marked for the early samples. Neuromuscular blockade was maximum after 5 to 7 minutes, much later than the peak venous concentration (1 to 3 minutes). Nonparametric analysis yielded (mean +/- SEM) a rate constant, concentration for 50% blockade, and slope of the effect-concentration relationship of 0.092 +/- 0.01 min-1, 379 +/- 27 ng/ml, and 7.3 +/- 1.67, respectively, when based on arterial samples. The values were statistically different (0.135 +/- 0.011 min-1, 235 +/- 42 ng/ml, and 3.41 +/- 0.37, respectively) when venous levels were used (p less than 0.05). It is concluded that forearm venous levels do not correspond to adductor pollicis neuromuscular blockade and the kinetics and kinetic-dynamic relationship for atracurium are heavily dependent on sampling site.

Adolescent↗

PubMed1991

Pharmacokinetics and pharmacodynamics of atracurium with and without previous suxamethonium administration.

Suxamethonium increases neuromuscular block produced by non-depolarizing agents administered subsequently. To determine if this effect has a pharmacokinetic or pharmacodynamic origin, 18 ASA physical status I or II adults received atracurium 0.2 mg kg-1, with (n = 10) or without (n = 8) previous injection of suxamethonium 1 mg kg-1, during a thiopentone-nitrous oxide-isoflurane (0.5% end-tidal) anaesthetic. Arterial blood samples were obtained and plasma atracurium concentration measured by HPLC. Train-of-four stimulation was applied to the ulnar nerve and the force of contraction of the adductor pollicis muscle was recorded. Mean (SEM) volume of distribution was slightly greater with previous suxamethonium (143 (13) ml kg-1) than without (109 (5) ml kg-1) (P less than 0.04). Mean elimination half-life was unaffected (20.3 (0.8) min and 20.4 (1.6) min, respectively). Neuromuscular block was more intense and recovery was slower with previous administration of suxamethonium. Atracurium concentration at 50% block (Cpss50) was 305 (30) ng ml-1 with and 454 (25) ng ml-1 without previous suxamethonium (P less than 0.01). It is concluded that suxamethonium may be associated with a slight increase in the volume of distribution of atracurium, but this effect is more than compensated by a decrease in atracurium concentration required for a given effect.

Adult↗

PubMed1990

Determination of atracurium and laudanosine in human plasma by high-performance liquid chromatography.

A high-performance liquid chromatographic method coupled with fluorometric detection has been developed for the determination of atracurium and its major end-product laudanosine in human plasma. The method enables good separation of atracurium from its metabolites after direct precipitation of plasma proteins. The assay is sensitive, reproducible and linear for atracurium concentrations ranging from 31.25 to 8000 ng/ml. In a clinical setting, drugs commonly administered during anesthesia did not interfere with the assay. This method provides a simple and time-saving alternative to existing methods.

Atracurium↗

PubMed1990

Influence of extreme obesity on the body disposition and neuromuscular blocking effect of atracurium.

The pharmacokinetics and pharmacodynamics of atracurium, a nondepolarizing neuromuscular blocking agent, were compared between morbidly obese patients and nonobese patients. Atracurium besylate (0.2 mg/kg) was administered intravenously as a bolus to patients who had received anesthesia. The force of contraction of the adductor pollicis was measured and plasma samples were collected for a 2-hour period. The concentrations of atracurium and its major end product, laudanosine, were determined by use of a chromatographic method. The pharmacokinetic-pharmacodynamic relationship was characterized by use of several models. No difference was observed between obese patients and nonobese patients in atracurium elimination half-life (19.8 +/- 0.7 versus 19.7 +/- 0.7 minutes), volume of distribution at steady state (8.6 +/- 0.7 versus 8.5 +/- 0.7 L), and total clearance (444 +/- 29 versus 404 +/- 25 ml/min). However, if values were expressed on a total body weight basis, there was a difference between obese and nonobese patients in the volume of distribution at steady state (0.067 versus 0.141 L/kg) and total clearance (3.5 +/- 0.2 versus 6.6 +/- 0.5 ml/min/kg). Although atracurium concentrations were consistently higher in obese patients than in nonobese patients, there was no difference in the time of recovery from neuromuscular blockade between the two groups. Consequently, the median effective concentration was higher in obese than in nonobese patients (470 +/- 46 versus 312 +/- 33 ng/ml).

Adult↗

PubMedDate not supplied

Emergency pain management: a Canadian Association of Emergency Physicians (CAEP) consensus document.

Pain is the most common presenting complaint heard in Emergency Medicine, yet it is poorly controlled. Evaluation of this pain should be with use of objective pain scales completed by the patient, not relying on physician impression. Treatment modalities available in the Emergency Department, a review of medications and their dosing as well as specifics to pediatric pain management are presented. The final section reviews situation or diagnosis specific pain control: headaches, renal colic, polytrauma victims, abdominal pain, soft tissue injury and acute arthritis. These recommendations are based on a Canadian Association of Emergency Physicians (CAEP) consensus conference held in April 1993. The literature was reviewed extensively and used as the basis for the consensus workshops and discussion. At the writing of the consensus paper, however, no specific ideas were borrowed from any one article. The appended bibliography is suggested reading, selected from the larger literature review. There are to date few controlled multi centre trials in overall pain management that would allow guidelines to be produced.

Analgesia↗

PubMedDate not supplied

A prospective blinded study on emergency pain assessment and therapy.

A prospective blinded observational study was carried out to document acute pain assessment and management in an academic emergency department. Over a 2-month period, 42 patients with a primary complaint of pain were studied. Physicians and nurses did not document levels of pain or changes in pain during patient stays. Eleven of 42 patients had severe pain upon arrival, 5 of whom received medications, only 1 obtaining good relief. No other patient received medication, although five others received some intervention for their pain. Eleven of 38 patients who were discharged home had severe pain on discharge. Despite minimal pain relief, patient satisfaction with pain management was relatively high. Pain assessment and treatment may be poorer than previous retrospective studies have indicated.

Acute Disease↗

PubMedDate not supplied

Procedural sedation and analgesia in the emergency department. Canadian Consensus Guidelines.

Procedural sedation and analgesia are core skills in emergency medicine. Various specialty societies have developed guidelines for procedural sedation, each reflecting the perspective of the specialty group. Emergency practitioners are most likely to embrace guidelines developed by people who understand emergency department (ED) skills, procedures, conditions, and case mix. Recognizing this, the Canadian Association of Emergency Physicians (CAEP) determined the need to establish guidelines for procedural sedation in the ED. In March, 1996, a national emergency medicine (EM) working committee, representing adult and pediatric emergency physicians, was established. This committee teleconferenced with representatives of the Canadian Anesthetic Society (CAS) to identify problems, perspectives, and controversial issues, and to define a process for guideline development. The EM committee subsequently reviewed existing literature, determined levels of evidence, and developed the document, which evolved based on feedback from the CAS and CAEP Standards Committees. The final version was approved by the CAEP Standards Committee and the CAEP Board of Directors, then submitted for peer review. These guidelines discuss the goals, definitions, and principles of ED sedation, and make recommendations for pre-sedation preparation, patient fasting, physician skills, equipment and monitoring requirements, and post-sedation care. The guidelines are aimed at non-anesthesiologists practicing part-time or full-time emergency medicine. They are applicable to ED patients receiving parenteral analgesia or sedation for painful or anxiety-provoking procedures. They are intended to increase the safety of procedural sedation in the ED.

Adult↗

PubMedDate not supplied

Canadian Association of Emergency Physicians Guidelines for the acute management of migraine headache.

The aim of this article is to provide an evidence-based guideline on the management of acute migraine headaches in the Emergency Department setting. After a Medline search that covered 1965 to the present, all randomized controlled trials were reviewed. Recommendations as to the efficacy of abortive anti-migraine medications were based on the Canadian Medical Association's Guideline for Guidelines. Classes of medications that are discussed include: dopamine antagonists, serotonin agonists, opioids, local anesthetics, non-steroidal anti-inflammatory agents, and steroids. The recommendations are limited to discussing the efficacy of specific medications, adverse effects to be expected, as well as associated headache rates after discharge. Specific recommendations as to which medication might offer a superior treatment have not been proposed due to lack of proper comparative trials as well as lack of information on headache and quality of life after discharge from the Emergency Department.

Canada↗