Effects of doxacurium chloride on biventricular cardiac function in patients with cardiac disease

Managing Delirium and Agitation in the Older Emergency Department Patient: The ADEPT Tool

Agitation and delirium are common reasons for older adults to seek care in the emergency department (ED). Providing care for this population in the ED setting can be challenging for emergency physicians. There are several knowledge translation gaps in how to best screen older adults for these conditions and how to manage them. A working group of subject-matter experts convened to develop an easy-to-use, point-of-care tool to assist emergency physicians in the care of these patients. The tool is designed to serve as a resource to address the knowledge translation and implementation gaps that exist in the field. The purpose of this article is present and explain the Assess, Diagnose, Evaluate, Prevent, and Treat tool. Participants were identified with expertise in emergency medicine, geriatric emergency medicine, geriatrics, and psychiatry. Background literature reviews were performed before the in-person meeting in key areas: delirium, dementia, and agitation in older adults. Participants worked electronically before and after an in-person meeting to finalize development of the tool in 2017. Subsequent work was performed electronically in the following months and additional expert review sought. EDs are an important point of care for older adults. Behavioral changes in older adults can be a manifestation of underlying medical problems, mental health concerns, medication adverse effects, substance abuse, or dementia. Five core principles were identified by the group that can help ensure adequate and thorough care for older adults with agitation or delirium: assess, diagnose, evaluate, prevent, and treat. This article provides background for and explains the importance of these principles related to the care of older adults with agitation. It is important for emergency physicians to recognize the spectrum of underlying causes of behavioral changes and have the tools to screen older adults for those causes, and methods to treat the underlying causes and ameliorate their symptoms.

Use of Muscle Relaxants in the Intensive Care Unit

Muscle relaxants are now routinely used in intensive care units despite the relative paucity of literature regarding their use, safety, and efficacy in this setting. Although the theory of the pharmacology of muscle relaxants is simple, many clinicians involved in critical care receive little or no formal education about their use either in medical school or during postgraduate training. Proper dosing, careful monitoring, awareness of possible side effects, and adequate sedation facilitate safe use of muscle relaxants in the intensive care unit. Muscle relaxants are not, however, a substitute for sedatives, hypnotics, amnesties, or analgesics and should rarely, if ever, be used without appropriate sedation and analgesia. A wide variety of agents now available with substantial differences in dosing, pharmacology, and side-effect profiles makes clearly delineated indications for use and end points for discontinuation necessary. Using muscle relaxants without monitoring is like using antiarrhythmics without an electrocardiograph.

Comparison of the cardiovascular effects of cisatracurium and vecuronium in patients with coronary artery disease

PURPOSE

Cisatracurium besylate (Nimbex Injection, Glaxo Wellcome Inc., Research Triangle Park, NC) is an intermediate-acting bis-benzylisoquinolinium neuromuscular blocking drug that is one of the stereoisomers of atracurium. At doses < or = 8 x ED95, it caused no clinically important cardiovascular side effects or histamine release in healthy patients. The purpose of the present study was to investigate the haemodynamic effects of high doses of cisatracurium in patients with coronary artery disease.

METHODS

One hundred patients undergoing myocardial revascularization participated in a pilot study (seven patients) and a double-blinded, randomized, controlled trial comparing the haemodynamic effects of cisatracurium with vecuronium at three centres. The patients were anaesthetized using oxygen 100%, with etomidate, fentanyl and a benzodiazepine, and tracheal intubation was facilitated using succinylcholine. After baseline haemodynamic measurements, the study drug was administered over 5-10 sec according to group assignment: Group A (pilot) cisatracurium, 0.20 mg.kg-1 (4 x ED95), (n = 7); Group B-cisatracurium, 0.30 mg.kg-1 (6 x ED95), (n x ED95), (n = 31); Group C-vecuronium, 0.30 mg.kg-1 (6 x ED95), (n = 31); Group D cisatracurium, 0.40 mg.kg-1 (8 x ED95), (n = 21); Group E-vecuronium, 0.30 mg.kg-1 (6 x ED95), (n = 10). The haemodynamic measurements were repeated at 2, 5, and 10 min after cisatracurium or vecuronium.

RESULTS

Two patients in Group D had > 20% decreases in MAP, but only one required therapy for hypotension. The haemodynamic changes from pre- to post-injection in the cisatracurium patients were minimal and similar to patients receiving vecuronium.

CONCLUSIONS

In patients with coronary artery disease, rapid cisatracurium (4-8 x ED95) boluses and vecuronium (6 x ED95) result in minor, clinically insignificant haemodynamic side effects.

Comparison of neuromuscular, cardiovascular, and histamine-releasing properties of doxacurium and pipecuronium

STUDY OBJECTIVES

To determine the neuromuscular, cardiovascular, and histamine releasing properties of doxacurium and pipecuronium at three times effective ED95 doses (3XFD95).

DESIGN

Prospective, randomized clinical trial of adult patients.

SETTING

University teaching hospital.

PATIENTS

20 ASA status I and II adult patients.

INTERVENTIONS

Subjects were anesthetized with thiopental sodium, fentanyl, and nitrous oxide and oxygen (N2O:O2). Plasma samples were taken preoperatively, after thiopental, and 2 and 5 minutes after doxacurium 75 micrograms/kg or pipecuronium 123 micrograms/kg were given for the determination of histamine levels. The ulnar nerve was stimulated via surface electrodes using train-of-four stimulation at 0.1 Hz. The force of contraction of adductor pollicis was recorded using a mechanomyograph. Recovery of the twitch response was followed and, if necessary, neuromuscular block was antagonized with neostigmine and glycopyrrolate.

MEASUREMENTS AND MAIN RESULTS

Three patients in the doxacurrium group and one patient in the pipecuronium group exhibited a marked increase in plasma histamine levels. In both groups statistically significant changes were seen in heart rate (HR) measurements (p < 0.02). Doxacurium had a slower onset than pipecuronium [3.1 +/- 0.2 min vs. 1.8 +/- 0.1 min (p < 0.0003)] and a more rapid recovery [72 +/- 8 min vs. 123 +/- 9 min (p < 0.01)].

CONCLUSION

Neither drug caused a clinically significant change in HR or histamine release. In the doses chosen for this study, the rate of onset of block is slower with doxacurium while recovery is more rapid. Histamine release in three patients was caused by thiopental, while in a fourth patient it may have been due to doxacurium.

A two-center comparison of the cardiovascular effects of cisatracurium (Nimbex) and vecuronium in patients with coronary artery disease

Cisatracurium (Nimbex) is an intermediate-acting benzylisoquinolinium neuromuscular blocker that is one of the stereoisomers of atracurium. It causes no clinically significant cardiovascular side effects or histamine release in doses up to 8 x ED95 in healthy patients. Seventy patients undergoing elective myocardial revascularization consented to participate in an Institutional Review Board approved pilot study (10 patients) and an open-label, randomized, controlled trial comparing the hemodynamic effects of cisatracurium with vecuronium (60 patients) at two centers. The patients were anesthetized using 100% oxygen, fentanyl, and midazolam, and tracheal intubation was facilitated with succinylcholine. At least 5 min after tracheal intubation, baseline hemodynamic measurements were obtained. The patients received 0.10 mg/kg of cisatracurium (2 x ED95) or 0.10 mg/kg of vercuronium (2 x ED90) as follows: cisatracurium over 60 s (Pilot Group A, n = 5); cisatracurium over 30 s (Pilot Group B, n = 5); cisatracurium over 5-10 s (Group C, n = 30); or vecuronium over 5-10 s (Group D, n = 30). The hemodynamic measurements were repeated at 2, 5, and 10 min after cisatracurium or vecuronium injection. There were no episodes of cutaneous flushing. One patient was hypotensive before and after cisatracurium administration, and was excluded from analysis. Otherwise, there were no episodes of hypotension requiring therapy in any patient after cisatracurium. Fifteen patients overall were excluded from the analysis for one or more of the following: light anesthesia, treatment for hypotension < 10 min prior to baseline, or equipment difficulties.(ABSTRACT TRUNCATED AT 250 WORDS)

Doxacurium block is not influenced by age

STUDY OBJECTIVE

To determine the influence of aging on the efficacy and safety of doxacurium.

DESIGN

Open, randomized, phase III study.

SETTING

Inpatient ophthalmic surgery clinic at a university medical center.

PATIENTS

30 elderly patients (65 years or older) compared with a control group of 30 younger patients (18 to 64 years).

INTERVENTIONS

An elective ophthalmological surgical intervention of more than 2 hours' expected duration with general anesthesia with isoflurane.

MEASUREMENTS AND MAIN RESULTS

Neuromuscular function after a bolus dose of doxacurium was monitored electromyographically. No significant difference was observed in maximum block achieved or onset time. Clinical duration of neuromuscular block was similar in both groups. Hemodynamic changes were clinically unimportant.

CONCLUSION

The use of doxacurium in elderly patients is possible with no need for dose adjustment. Doxacurium might be a good choice for patients with cardiac disease who are scheduled for long surgical procedures.

Hemodynamic and pharmacodynamic comparison of doxacurium and high-dose vecuronium during coronary artery bypass surgery: a cost-benefit study

Doxacurium (DOX), a new nondepolarizing neuromuscular blocking drug (NMBD), was compared in a randomized, double-blind fashion to high-dose vecuronium (VEC) in 60 coronary artery bypass grafting (CABG) patients. A third group of 15 patients older than 70 years of age (DOX-70) was added to compare the effects of DOX to VEC in the older population. Endpoints of the study were hemodynamic stability, ease of ventilation and intubation, anesthesiologist's satisfaction, drug interventions to correct hemodynamic instability, and total cost of the drug. Anesthesia was induced with fentanyl (30 micrograms/kg) along with the NMBD (DOX 80 micrograms/kg, VEC 400 micrograms/kg) over a 2-minute period. Following induction, heart rate (HR) and mean arterial pressure (MAP) were decreased (P < 0.01) in all groups. Tracheal intubation caused the HR to return to baseline in the DOX-70 group. There was no difference in central venous pressure, pulmonary artery occlusive pressure, cardiac index, systemic vascular resistance, and drug intervention for DOX and VEC. None of the patients had evidence of myocardial ischemia. There was a statistically significant but clinically irrelevant decrease in central venous pressure and systemic vascular resistance in the DOX-70 group. The durations of the induction and maintenance doses of DOX were similar in the younger and older patients. Although the intubating dose of VEC had a faster onset of action, this had no effect on the ease of ventilation, conditions for tracheal intubation, and overall anesthesiologist satisfaction. The total cost for each NMBD was not different.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of hemodynamic responses to pipecuronium and doxacurium in patients undergoing valvular surgery while anesthetized with fentanyl

Hemodynamic responses to pipecuronium bromide or doxacurium chloride were compared in patients undergoing valvular heart surgery. Thirty ASA class III-IV patients of either sex, mean age 62 +/- 3 years (+/- SD), weight 70 +/- 3 kg, were randomly selected to receive either doxacurium (0.08 mg/kg) or pipecuronium (0.15 mg/kg). Hemodynamic parameters were determined at preinduction, induction, 2 minutes and 6 minutes following administration of the muscle relaxant. Anesthetic induction consisted of midazolam, 0.10 mg/kg, followed by fentanyl, 5 micrograms/kg. Measured or calculated parameters were as follows: mean arterial pressure, heart rate, cardiac index, mean pulmonary artery pressure, systemic vascular resistance index, central venous pressure, pulmonary capillary wedge pressure, stroke volume index, left and right stroke work indices, and pulmonary vascular resistance index. Awake patients who had been randomly assigned to the pipecuronium group had significantly higher pulmonary capillary wedge pressures (22 +/- 2 v 15 +/- 2 mmHg; P < 0.05) and heart rates (86 +/- 3 v 64 +/- 5 beats/min; P < 0.05) than awake patients in the doxacurium group. Following induction, both wedge pressure and heart rate were not significantly different between the two groups. Compared to hemodynamics at induction, there were no clinically significant changes following administration of pipecuronium or doxacurium.

The use of muscle relaxants in the intensive care unit

Neuromuscular blocking agents are frequently used in the Intensive Care Unit to facilitate tracheal intubation and the application of continuous paralysis. This review will focus on various conditions of the critically ill patient such as multi-organ dysfunction, acid-base and electrolyte imbalance, prolonged immobility, multiple drug interactions and specific disease/injury processes that may affect the pharmacokinetic and pharmacodynamic behaviour of muscle relaxants. As such, due to the complex nature of the critically ill patients, the effects of neuromuscular blocking agents are unpredictable. Therefore, guidelines regarding their administration and the methodology and requirement for continuous bedside monitoring of neuromuscular function will be presented.

Newer neuromuscular blocking drugs. An overview of their clinical pharmacology and therapeutic use

Four new nondepolarising muscle relaxants, pipecuronium bromide, doxacurium chloride, mivacurium chloride and Org 9426 (rocuronium) offer alternatives to the established agents atracurium besilate and vecuronium bromide. Pipecuronium and Org 9426 are steroidal compounds, the latter being a monoquaternary agent, whereas doxacurium and mivacurium are bisquaternary benzylisoquinolinium compounds. Pipecuronium and doxacurium have a relatively slow onset and a long duration of action. Pipecuronium produces maximum block in 3 to 6 min when given in a dose of 45 to 80 micrograms/kg, and a duration of clinical relaxation of between 40 and 110 min. Doxacurium is more potent, but is the least rapid and the longest acting relaxant currently available. When administered in doses of 37 to 80 micrograms/kg, it produces maximum block within 3.5 to 10 min, with a duration of clinical relaxation of 77 to 164 min. The advantage of both pipecuronium and doxacurium is their cardiovascular stability. Both agents are primarily eliminated via the kidneys and both have now been licensed for use in the US. Mivacurium is a muscle relaxant with a short duration of action. When administered in doses of 0.1 to 0.25 mg/kg it produces maximum block in 2 to 4 min, but the duration of clinical relaxation is less than 20 min. Higher doses which could induce a faster neuromuscular block are unfortunately associated with some histamine liberation. The drug is metabolised by plasma cholinesterase. Mivacurium has also been licensed for use in the US. Org 9426 is an agent with a rapid onset but an intermediate duration of action. A dose of 0.5 to 0.6 mg/kg induces maximum block in about 1.5 min and has a duration of clinical relaxation of about 30 min. The rapid onset of effect could be useful for early intubation as an alternative to suxamethonium chloride. However, much more clinical experience is needed with this agent, particularly with regard to duration of action of larger doses and occurrence of side effects. The drug is mainly eliminated via the liver.