Double-blind, randomized, multicenter study of doxacurium vs. pancuronium in intensive care unit patients who require neuromuscular-blocking agents

Effects of Natural Products on Neuromuscular Junction

Neuromuscular junction (NMJ) disorders result from damage, malfunction or absence of one or more key proteins involved in neuromuscular transmission, comprising a wide range of disorders. The most common pathology is antibody-mediated or downregulation of ion channels or receptors, resulting in Lambert-Eaton myasthenic syndrome, myasthenia gravis, and acquired neuromyotonia (Isaac's syndrome), and rarely congenital myasthenic syndromes caused by mutations in NMJ proteins. A wide range of symptomatic treatments, immunomodulating therapies, or immunosuppressive drugs have been used to treat NMJ diseases. Future research must be directed at better understanding of the pathogenesis of these diseases, and developing novel disease-specific treatments. Numerous secondary metabolites, especially alkaloids isolated from plants have been used to treat NMJ diseases in traditional and clinical practices. An ethnopharmacological approach has provided leads for identifying new treatment for NMJ diseases. In this review, we performed a literature survey in Pubmed, Science Direct, and Google Scholar to gather information on drug discovery from plant sources for NMJ disease treatments. To date, most research has focused on the effect of herbal remedies on cholinesterase inhibitory and antioxidant activities. This review provides leads for identifying potential new drugs from plant sources for the treatment of NMJ diseases.

Review of Continuous Infusion Neuromuscular Blocking Agents in the Adult Intensive Care Unit

The use of continuous infusion neuromuscular blocking agents remains controversial. The clinical benefit of these medications may be overshadowed by concerns of propagating intensive care unit-acquired weakness, which may prolong mechanical ventilation and impair the inability to assess neurologic function or pain. Despite these risks, the use of neuromuscular blocking agents in the intensive care unit is indicated in numerous clinical situations. Understanding pharmacologic nuances and clinical roles of these agents will aid in facilitating safe use in a variety of acute disease processes. This article provides clinicians with information regarding pharmacologic differences, indication for use, adverse effects, recommended doses, ancillary care, and monitoring among agents used for continuous neuromuscular blockade.

Analytic reviews: managing the agitated patient in the ICU: sedation, analgesia, and neuromuscular blockade

Physical and psychological distress is exceedingly common among critically ill patients and manifests generically as agitation. The dangers of over- and undertreatment of agitation have been well described, and the intensive care unit (ICU) physician must strike a balance in the fast-paced, dynamic ICU environment. Identification of common reversible etiologies for distress may obviate the need for pharmacologic therapy, but most patients receive some combination of sedative, analgesic, and neuroleptic medications during the course of their critical illness. As such, understanding key pharmacologic features of commonly used agents is critical. Structured protocols and objective assessment tools can optimize drug delivery and may ultimately improve patient outcomes by reducing ventilator days, ICU length of stay, and by reducing cognitive dysfunction.

Neuromuscular blockers in early acute respiratory distress syndrome

BACKGROUND

In patients undergoing mechanical ventilation for the acute respiratory distress syndrome (ARDS), neuromuscular blocking agents may improve oxygenation and decrease ventilator-induced lung injury but may also cause muscle weakness. We evaluated clinical outcomes after 2 days of therapy with neuromuscular blocking agents in patients with early, severe ARDS.

METHODS

In this multicenter, double-blind trial, 340 patients presenting to the intensive care unit (ICU) with an onset of severe ARDS within the previous 48 hours were randomly assigned to receive, for 48 hours, either cisatracurium besylate (178 patients) or placebo (162 patients). Severe ARDS was defined as a ratio of the partial pressure of arterial oxygen (PaO2) to the fraction of inspired oxygen (FIO2) of less than 150, with a positive end-expiratory pressure of 5 cm or more of water and a tidal volume of 6 to 8 ml per kilogram of predicted body weight. The primary outcome was the proportion of patients who died either before hospital discharge or within 90 days after study enrollment (i.e., the 90-day in-hospital mortality rate), adjusted for predefined covariates and baseline differences between groups with the use of a Cox model.

RESULTS

The hazard ratio for death at 90 days in the cisatracurium group, as compared with the placebo group, was 0.68 (95% confidence interval [CI], 0.48 to 0.98; P=0.04), after adjustment for both the baseline PaO2:FIO2 and plateau pressure and the Simplified Acute Physiology II score. The crude 90-day mortality was 31.6% (95% CI, 25.2 to 38.8) in the cisatracurium group and 40.7% (95% CI, 33.5 to 48.4) in the placebo group (P=0.08). Mortality at 28 days was 23.7% (95% CI, 18.1 to 30.5) with cisatracurium and 33.3% (95% CI, 26.5 to 40.9) with placebo (P=0.05). The rate of ICU-acquired paresis did not differ significantly between the two groups.

CONCLUSIONS

In patients with severe ARDS, early administration of a neuromuscular blocking agent improved the adjusted 90-day survival and increased the time off the ventilator without increasing muscle weakness. (Funded by Assistance Publique-Hôpitaux de Marseille and the Programme Hospitalier de Recherche Clinique Régional 2004-26 of the French Ministry of Health; ClinicalTrials.gov number, NCT00299650.)

A Markov computer simulation model of the economics of neuromuscular blockade in patients with acute respiratory distress syndrome

Background

Management of acute respiratory distress syndrome (ARDS) in the intensive care unit (ICU) is clinically challenging and costly. Neuromuscular blocking agents may facilitate mechanical ventilation and improve oxygenation, but may result in prolonged recovery of neuromuscular function and acute quadriplegic myopathy syndrome (AQMS). The goal of this study was to address a hypothetical question via computer modeling: Would a reduction in intubation time of 6 hours and/or a reduction in the incidence of AQMS from 25% to 21%, provide enough benefit to justify a drug with an additional expenditure of $267 (the difference in acquisition cost between a generic and brand name neuromuscular blocker)?

Methods

The base case was a 55 year-old man in the ICU with ARDS who receives neuromuscular blockade for 3.5 days. A Markov model was designed with hypothetical patients in 1 of 6 mutually exclusive health states: ICU-intubated, ICU-extubated, hospital ward, long-term care, home, or death, over a period of 6 months. The net monetary benefit was computed.

Results

Our computer simulation modeling predicted the mean cost for ARDS patients receiving standard care for 6 months to be $62,238 (5% – 95% percentiles $42,259 – $83,766), with an overall 6-month mortality of 39%. Assuming a ceiling ratio of $35,000, even if a drug (that cost $267 more) hypothetically reduced AQMS from 25% to 21% and decreased intubation time by 6 hours, the net monetary benefit would only equal $137.

Conclusion

ARDS patients receiving a neuromuscular blocker have a high mortality, and unpredictable outcome, which results in large variability in costs per case. If a patient dies, there is no benefit to any drug that reduces ventilation time or AQMS incidence. A prospective, randomized pharmacoeconomic study of neuromuscular blockers in the ICU to asses AQMS or intubation times is impractical because of the highly variable clinical course of patients with ARDS.

Sedation, analgesia, and neuromuscular blockade in sepsis: An evidence-based review

OBJECTIVE

In 2003, critical care and infectious disease experts representing 11 international organizations developed management guidelines for sedation, analgesia, and neuromuscular blockade in sepsis that would be of practical use for the bedside clinician, under the auspices of the Surviving Sepsis Campaign, an international effort to increase awareness and improve outcome in severe sepsis.

DESIGN

The process included a modified Delphi method, a consensus conference, several subsequent smaller meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee.

METHODS

The modified Delphi methodology used for grading recommendations built on a 2001 publication sponsored by the International Sepsis Forum. We undertook a systematic review of the literature graded along five levels to create recommendation grades from A to E, with A being the highest grade. Pediatric considerations to contrast adult and pediatric management are in the article by Parker et al. on p. S591.

CONCLUSION

There is no preferred sedative or analgesic agent for use in the critically ill septic patient during mechanical ventilation. Protocols should be utilized for administration of sedation with predefined sedation scale targets. Either intermittent bolus sedation or continuous infusion sedation to predetermined end points with daily interruption/lightening of continuous infusion sedation with awakening and re-titration, if necessary, are recommended. Neuromuscular blockade should be avoided if possible and, if used continuously, requires twitch monitoring.

Neuromuscular-blocking drugs. Use and misuse in the intensive care unit

The use of NMB agents for more than 24 to 48 hours in critically ill patients is associated with many potential complications. Neuromuscular-blocking drugs should be used only when their use is essential for optimal patient care. The indications for neuromuscular blockade must be defined clearly, and patients should be evaluated during treatment for the need for continued muscle relaxation. The smallest doses of NMB agents that will accomplish clinical goals should be used. This dosage can be determined through clinical evaluations and peripheral nerve monitoring. It is essential that all patients treated with NMB drugs receive appropriate sedation and analgesia. Myopathies, neuropathies, and alterations of the neuromuscular junction can occur in the ICU setting, and nondepolarizing muscle relaxants seem to be involved in the development of these disorders. Clinicians should be aware of risk factors that may predispose certain patients to neuromuscular complications, including sepsis and the use of high-dose steroids. Neuromuscular-blocking agents should be avoided in these patients if possible. Although not proved, early recognition and treatment of iatrogenic neuromuscular complications may improve patient outcome.

The pharmacokinetics of cisatracurium in patients with acute respiratory distress syndrome

Continuous neuromuscular blockade is often necessary in patients being treated for acute respiratory distress syndrome (ARDS) to optimize oxygenation. In this study, neuromuscular blockade (no response to two responses at the train-of-four stimulation at the orbicularis oculi muscle) was achieved in six patients with ARDS by a continuous infusion of cisatracurium. The plasma concentration of cisatracurium during the infusion averaged 1.00 (0.25-1.45) microg/mL, expressed as median (range). The clearance and half-life were 6.5 (3.3-7.6) mL. min(-1). kg(-1) and 25 (16-48) min, respectively. The laudanosine plasma concentrations were 0.70 (0.12-1.20) microg/mL. The pharmacokinetic variables of cisatracurium are similar to those of patients without organ failure undergoing elective surgery. Plasma laudanosine levels always remained well less that those associated with seizure activity in animal models. Long-term infusion of cisatracurium was not associated with any side effects. Cisatracurium is a suitable muscle relaxant when deep and continuous levels of muscle relaxation are required in patients treated for ARDS.

IMPLICATIONS

We studied the pharmacokinetics of cisatracurium in six patients treated for respiratory distress syndrome by continuous muscle relaxation. A deep degree of neuromuscular blockade corresponding to abolition of two responses at the orbicularis oculi to train-of-four stimulation was obtained in all patients. The pharmacokinetic variables observed in these severely ill patients were similar to those of anesthetized patients. No accumulation of laudanosine was seen. Cisatracurium appears to be suitable when continuous muscle relaxation is required in critically ill patients.

Paralysis in the critically ill: intermittent bolus pancuronium compared with continuous infusion

OBJECTIVES

To compare recovery times from neuromuscular blockade between two groups of critically ill patients in whom pancuronium was administered by continuous infusion or intermittent bolus injection. To compare the mean pancuronium requirements (milligrams per kilogram per hour) and to assess the incidence of prolonged recovery times (>12 hrs) and residual muscle weakness.

DESIGN

Prospective, observational cohort.

SETTING

Intensive care unit in a university-affiliated hospital.

PATIENTS

A total of 30 mechanically ventilated patients who required pharmacologic paralysis. Patients were excluded if they had renal failure (creatinine clearance <30 mL/min), heart rate >130 beats/min, hepatic failure, peripheral nerve disease or myopathy, stroke, spinal cord damage, or myasthenia gravis.

INTERVENTIONS

Patients were assigned to receive pancuronium either by continuous infusion (n = 14) or intermittent bolus (n = 16). Depth of paralysis was titrated to maintain one or two responses to Train-of-Four stimulation with an accelerograph and desired clinical goals. Recovery time was defined as time from discontinuation of muscle relaxant until the amplitude of the fourth twitch, measured every 15-30 min using an accelerograph, was 70% the amplitude of the first twitch (Train-of-Four > or = 0.7).

MEASUREMENTS AND MAIN RESULTS

These patients included the only three patients with status asthmaticus in our study. The groups were similar with respect to age, sex, weight, Acute Physiology and Chronic Health Evaluation II score, mode of ventilation, creatinine clearance, indications for paralysis, and duration of pancuronium administration. The median time for patients to recover from paralysis was 3.5 hrs (95% confidence interval, 1.82-5.18) in the infusion group vs. 6.3 hrs (95% confidence interval, 3.40-9.19) in the intermittent bolus group (p = .10). Less drug was administered in the intermittent group (mean, 0.02+/-0.01 mg/kg/hr) than by infusion (mean, 0.04+/-0.01 mg/kg/hr; p < .001). Six patients (five in the infusion group and one in the intermittent group) developed persistent severe muscle weakness. In addition, six different patients (three from each group) had prolonged recovery >12 hrs.

CONCLUSIONS

Our study suggests that recovery time after paralysis with continuous infusion is faster than that after intermittent bolus injection. Although more pancuronium was administered in the continuous-infusion group, recovery time was not prolonged as a consequence. It is uncertain whether pancuronium given by infusion increases the risk of persistent muscle weakness.

Monitoring neuromuscular blockade in the intensive care unit: the peripheral nerve stimulator

Traditionally, neuromuscular blocking agents (NMBAs) have been administered in the operating room as an adjunct to anesthetics. Recent studies in the United States have indicated that 98% of the anesthesiologists and critical care nurses surveyed use NMBAs at least occasionally. When monitoring the use of NMBAs, a combination of clinical monitoring and peripheral nerve stimulator monitoring has been recommended. However, the most effective techniques have yet to be described. Understanding the complexities of NMBAs and the absolute need for accurate monitoring techniques is imperative for clinicians. The purpose of this literature review is to evaluate current literature regarding monitoring techniques of NMBAs and to guide the advanced practice nurse's role in critical care.

[The use of curare-like agents in resuscitation]

OBJECTIVE

To analyse current data on use of neuromuscular blocking agents (NBA) in the intensive therapy unit (ITU) patients and to propose practice guidelines.

DATA SOURCES

We did a Medline search of French and English language articles on NBA administration in ITU patients from 1960 to 1998. Data were also selected from our own collection of articles and books.

STUDY SELECTION

Original articles, clinical cases, letters to the editor and review articles were considered.

DATA EXTRACTION

Data on pharmacology of NBA in the ITU patient were extracted, as well as data on administration patterns and cost.

DATA SYNTHESIS

The indications for myorelaxation in ITU patients include either short term use, as in anaesthesia, or long term administration for facilitation of mechanical ventilation, control of increased intracranial pressure, status epilepticus, tetanus and oxygen demand in case of muscular hyperactivity, diagnostic and therapeutic procedures facilitation. A beneficial effect of NBA on the prognosis of the disease for which these agents have been used is not yet proven. Suxamethonium, because for its short onset time and duration of action, is the agent of choice for endotracheal intubation if myorelaxation is required. Among the benzylisoquinolines, atracurium and besilate of cisatracurium are convenient agents in ITU patients, whereas mivacurium is of no special interest. Among the aminosteroids, pancuronium and vecuronium are the most often used agents in the ITU. Rocuronium has not yet been extensively assessed. Myorelaxants carry risks for morbidity and mortality. The difficulty to assess the neurological status and the level of sedation is a recognised adverse effect. An accidental disconnection from the circuit and the resulting asphyxia is nowadays recognised without delay by the ventilator. NBAs increase the rate of bronchopulmonary infections. Cardiovascular complications include extreme bradycardia or sinus arrest following vecuronium administration, and cardiac arrest after suxamethonium injection mainly in burned or traumatised patients. Conversely to anaesthesia, NBAs do not carry a significant risk for anaphylactic or anaphylactoid complications in the ITU. Tachyphylaxis occurs mainly in burns and other pathologies modifying acetylcholine receptors. Neuromuscular complications include myopathy from steroids, postparalytic syndrome, deconditioning syndrome and intensive care polyneuropathy. Prolonged curarisation after discontinuation of NBA administration has a multifactorial origin and must be differentiated from neuromuscular complications. For prolonged neuromuscular blockade, pancuronium, vecuronium and atracurium are the agents of choice. The association with an adequate sedation is essential. Assessment of depth of neuromuscular blockade is not based on clinical symptoms but on train-of-four (TOF) twitch monitoring. A convenient basic relaxation is usually obtained with the suppression of the two last responses to TOF.

CONCLUSION

The use of NBA in ITU patient should result from a rational decision making procedure, the blockade titrated with a TOF monitor and maintained as superficially and shortly as possible.

Dose response, recovery, and cost of doxacurium as a continuous infusion in neurosurgical intensive care unit patients

OBJECTIVES

To determine the optimal dosing of doxacurium as a continuous infusion in neurosurgical patients with traumatic brain injury; to determine the effects of bolus administration of doxacurium on heart rate (HR), blood pressure (BP), and intracranial pressure (ICP); to monitor neuromuscular recovery after discontinuation of prolonged doxacurium infusion; and to compare the cost of doxacurium with other current neuromuscular blocking drugs.

DESIGN

Prospective, open-label study.

SETTING

Neurosurgical intensive care unit (ICU) of a university-affiliated teaching hospital.

PATIENTS

Eight critically ill, mechanically ventilated patients with traumatic head injury and normal renal and hepatic function. Patients had ICP monitoring.

INTERVENTIONS

A bolus injection of doxacurium (0.05 mg/kg) followed by a continuous infusion (0.015 mg/kg/hr), adjusted to maintain one twitch during Train-of-Four nerve stimulation of the adductor pollicis muscle.

MEASUREMENTS AND MAIN RESULTS

Bolus injections of doxacurium did not alter the HR, BP, or ICP. Patients were paralyzed 66 +/- 12 (SEM) hrs, with recovery of the fourth twitch occurring 118 +/- 19 mins after infusion of the doxacurium was discontined. There were no incidences of prolonged weakness, myopathy, or other adverse events.

CONCLUSIONS

Continuous infusion of doxacurium provides stable neuromuscular blockade for neurosurgical patients with traumatic brain injury. Doxacurium is devoid of clinically important interactions with HR, BP, or ICP and is less costly than other neuromuscular blockers used in the ICU.

A prospective, randomized, controlled evaluation of peripheral nerve stimulation versus standard clinical dosing of neuromuscular blocking agents in critically ill patients

OBJECTIVES

To determine if vecuronium doses individualized by peripheral nerve stimulation are lower than those doses chosen by standard clinical techniques; and to determine whether patients monitored by peripheral nerve stimulation exhibit shorter recovery times and less prolonged neuromuscular blockade after discontinuation of vecuronium than control patients.

DESIGN

A prospective, randomized, controlled, single-blind trial.

SETTING

Two ten-bed medical intensive care units of a 937-bed tertiary care, not-for-profit, teaching hospital and health system.

PATIENTS

Mechanically ventilated patients requiring continuous neuromuscular blockade as part of their therapy.

INTERVENTIONS

After obtaining written, informed consent and baseline neurologic examinations, patients were randomized to treatment, where dosing was individualized by peripheral nerve stimulation or standard clinical assessment. Doses in the peripheral nerve stimulation group were adjusted to 90% blockade (Train-of-Four of 1/4). The standard clinical dosing group received doses individualized to clinical response by the medical team (blinded to Train-of-Four). Differences between groups were evaluated by Wilcoxon matched-pairs signed rank test.

MEASUREMENTS AND MAIN RESULTS

A total of 77 patients (35 standard clinical patients vs. 42 peripheral nerve stimulation patients) were enrolled in the study. Despite no difference in initial doses and time to reach 90% blockade or clinical response between groups, the peripheral nerve stimulation group used less drug than the standard clinical group (0.040 +/- 0.028 vs. 0.070 +/- 0.030 mg/kg/hr, respectively, p = .001). The total cumulative amount of vecuronium for the episode of paralysis was greater in the control group (285.8 +/- 246.6 vs. 137.1 +/- 106.4 mg, p = .001). The peripheral nerve stimulation group recovered neuromuscular function (relative risk of 1.85, with 95% confidence interval [CI] of 1.02-3.35, p = .039) and spontaneous ventilation (relative risk of 1.86, 95% CI 1.00-3.45, p = .047) faster than the control group. In patients, adjusting for renal dysfunction, the likelihood of a faster recovery in the peripheral nerve stimulation group increased for neuromuscular function (relative risk of 1.89, 95% CI of 1.07-3.32, p = .018) and spontaneous ventilation (relative risk of 2.27, 95% CI of 1.23-4.21, p = .019). Patients with combined renal and liver failure similarly demonstrated a faster recovery in the peripheral nerve stimulation group. The recovery was affected to a lesser extent by adjusting for concurrent aminoglycoside and corticosteroid administration.

CONCLUSIONS

Use of peripheral nerve stimulation for monitoring the degree of blockade and adjusting drug doses in continuously paralyzed critically ill medical patients results in lower doses of vecuronium to maintain a desired depth of paralysis, and allows a faster recovery of neuromuscular function and spontaneous ventilation.

Monitoring interactions between spontaneous respiration and mechanical inflations in preterm neonates

OBJECTIVES

To determine the value of a new bedside monitor in assessing the interactions between spontaneous respiratory activity and ventilator inflations in preterm infants; and to monitor continuously the degree of patient-ventilator synchrony and the stability of spontaneous respiratory effort during different modes of ventilation and in response to care procedures.

DESIGN

A prospective, observational study of physiologic variables recorded by a computerized monitoring system.

SETTING

A neonatal intensive care unit in a teaching hospital.

PATIENTS

Thirty-one neonates (median gestational age of 28 wks [range 24 to 36]; median birth weight of 942 g [range 624 to 2940]) were monitored during conventional mandatory ventilation at rates ranging from 47 to 108 inflations/min, and 22 infants (median gestational age of 27.5 wks [range 25 to 40]; median birth weight of 1345 g [range 510 to 3490]) were monitored during patient-triggered ventilation. All infants were sedated as part of the routine care policy.

INTERVENTIONS

Spontaneous respiration (abdominal pressure capsule) and ventilator inflations (airway pressure) were recorded continuously for periods of up to 3 days in mechanically ventilated preterm infants.

MEASUREMENTS AND MAIN RESULTS

The monitoring system uses the Frequency Tracking Locus method to derive the interaction Score, which quantifies the degree of entrainment of the spontaneous respiratory pattern by the ventilator. This analysis was applied to airway pressure and abdominal capsule signals. A perfect 1:1 interaction between spontaneous inspirations and mechanical inflations returns an interaction Score of 1.00, and irregular interactions return a score of > 1.5. During conventional mandatory ventilation, a total of 53,074 16-sec epochs (representing 782,811 spontaneous breaths) were studied in 31 preterm infants: 27.4% of epochs showed a 1:1 interaction, 60.5% a non 1:1 interaction, and 12.1% indicated a passive (i.e., infant apneic) response by the infant, despite excluding periods when paralyzing agents were used. The median interaction Score value during 1:1 interactions was 1.2, whereas for non 1:1 interactions the interaction Score was 2.2. One to one entrainment occurred at conventional mandatory ventilation rates between 50 and 85 inflations/min: for many infants, such entrainment was achievable over a range of conventional mandatory ventilation rates, while in some infants respiration was unstable at all rates of conventional mandatory ventilation. During passive ventilation, the median Interaction Score was 1.0. During patient-triggered mechanical ventilation, approximately 67,150 spontaneous respiratory cycles, represented by 3,592 16-sec epochs, were studied in 22 infants. Overall, 19.5% (702) of epochs showed the criteria for ideal triggering by spontaneous inspiration and 19.6% (703) showed autotriggering. In 60.9% (2187) of epochs, a non 1:1 interaction was noted. During ideal patient-triggered mechanical ventilation, the median interaction Score was 1.14; during passive (autotriggered) ventilation, the median Interaction Score was 1.05; and during non 1:1 ventilation, the median score was 1.74. "Autotriggering" was found frequently in infants of < or = 28 wks gestation. The monitor was able to distinguish between stable and unstable interactions and apnea during conventional mandatory ventilation and patient-triggered mechanical ventilation by reference to the Interaction Score value.

CONCLUSIONS

We describe a new kind of bedside monitor for the Interpretation of respiratory data. Unlike other methods, it is able to give the clinician a continuous measure of patient-ventilator interaction which is easy to interpret. It appears to have wide-spread application in neonatal intensive care nurseries where the babies' own breathing efforts can affect the efficiency of respiration and cause unwanted physiologic instability. The monitor can be used to determine the optimal ventilatory settings to

Neuromuscular transmission and its pharmacological blockade. Part 4: Use of relaxants in paediatric and elderly patients, in obstetrics, and in the intensive care unit

The pharmacodynamic and pharmacokinetic characteristics of the non-depolarizing muscle relaxants are dependent on age. Thus differences are found between paediatric patients, adults, and elderly patients. Muscle relaxants cross the placenta and thus may cause problems in the fetus. Many of the potential adverse effects of relaxant administration are seen more pronounced in intensive care patients. Prolonged effects and problems in wearing patients from the ventilator are observed when muscle relaxants are used in such patients. Critical illness neuropathy is a syndrome different from relaxant induced neuromyopathy, but may be enhanced by relaxant administration.

Recovery from doxacurium infusion administered to produce immobility for more than four days in pediatric patients in the intensive care unit

Doxacurium was administered by titrated infusion to 14 pediatric patients for 4.7-12.3 days after laryngotracheal reconstruction to produce minimum spontaneous movement and less than five posttetanic movements of the first toe after stimulation of the posterior tibial nerve. Recovery was documented by stimulation of the ulnar nerve with 2 Hz for 2 s (train-of-four [TOF]) at intervals of 1 min and measurement of the ratio of the fourth to the first response (TOF ratio) at the adductor pollicis. During spontaneous recovery, the TOF ratio was between 0.4 and 0.7 for 0.6-3.3 h, mean (SEM) 2.2 (0.31) h. The TOF ratio equaled 1 between 4.7 and 23.0 h, mean (SEM) 11.0 (2.1) h after termination of doxacurium infusion. In six of the patients, weakness and decreased coordination were noted for a few days to weeks postoperatively. There were no complications related to impairment of upper airway function or ventilation in those patients who had recovery of neuromuscular transmission to the extent of TOF ratio equal to 1 prior to extubation or in those patients in whom weakness or lack of coordination was noted after tracheal extubation.

Oxygen delivery, oxygen consumption, and gastric intramucosal pH are not improved by a computer-controlled, closed-loop, vecuronium infusion in severe sepsis and septic shock

OBJECTIVE

To investigate the influence of the neuromuscular blocking agent vecuronium on oxygen delivery (DO2), oxygen consumption (VO2), oxygen extraction ratio, and gastric intramucosal pH in heavily sedated patients with severe sepsis or septic shock.

DESIGN

Prospective, randomized, placebo-controlled, cross-over trial.

SETTING

University hospital intensive care unit.

PATIENTS

Eighteen mechanically ventilated patients with severe sepsis or septic shock.

INTERVENTIONS

All patients were heavily sedated. After baseline measurement, a computer-controlled, closed-loop infusion of either vecuronium or saline was initiated and further measurements were made at 40 and 60 mins. The procedure was repeated with the alternative agent after return of neuromuscular function.

MEASUREMENTS AND MAIN RESULTS

DO2, VO2, intramucosal pH were monitored using pulmonary artery catheters, a gas exchange monitor, and gastric tonometers. Changes from baseline were compared (paired t-test, p = .05). The vecuronium closed-loop infusion achieved T1 between 5% and 15% at 40 mins. There was a significant difference in the changes from baseline for static respiratory compliance in the vecuronium closed-loop infusion group compared with the saline closed-loop infusion group. There was no significant difference in the change from baseline for systemic or pulmonary vascular resistance, DO2, VO2, oxygen extraction ratio, or intramucosal pH.

CONCLUSIONS

In these patients, vecuronium infusion achieved the targeted level of paralysis and improved respiratory compliance but did not alter intramucosal pH, VO2, DO2, or oxygen extraction ratios. With deep sedation, neuromuscular blockade in severe sepsis/septic shock does not significantly influence oxygen flux and should be abandoned as a routine method of improving tissue oxygenation in these patients.

Postal survey on the long-term use of neuromuscular block in the intensive care

OBJECTIVE

To assess the long-term use of neuromuscular blocking (NMB) agents in intensive care, especially with reference to the potential problems of the long-term use of NMB drugs in the intensive care unit (ICU).

METHOD

A postal survey questionnaire was sent to 409 ICUs in Great Britain.

RESULTS

Two hundred thirty-eight completed questionnaires were returned and analysed. Most ICUs were anaesthetist-led (85.8%) with only five ICUs being staffed by full-time intensivists. Facilitation of mechanical ventilation and increased intracranial pressure were the main indications for the prolonged use of neuromuscular blockade. Atracurium and vecuronium (83%) were administered most commonly by bolus alone (13.8%), bolus followed by continuous infusion (23.9%) or continuous infusion only (60.9%). The most frequently cited criteria for the use of either vecuronium or stracurium were their pharmacokinetics and haemodynamic stability. Neuromuscular block was most commonly monitored clinically (91.7%), with only 8.3% of the responders using a peripheral nerve stimulator. All responders indicated the concomitant use of sedatives (propofol/midazolam alone or in combination in 89.4% of responders) and/or opioids (morphine, fentanyl or alfentanil in 74.8% of respondents) with muscle relaxants.

CONCLUSION

Most responders agreed that while neuromuscular block in the ICU population may provide advantages, it cannot be considered benign. Indeed, a great majority consider that NMB agents should be used only as a last option and -for as short a period as possible.

Does a full-time, 24-hour intensivist improve care and efficiency?

This article reviews the hypothesis that staffing with full-time intensive care physicians leads to improvements in the management of ICUs and in the outcome for ICU patients. Variations in the professional organization of critical care units in the United States are discussed. The advantages and disadvantages of open, closed, and transitional (comanagement) ICU organizational structures are presented.

Practice parameters for sustained neuromuscular blockade in the adult critically ill patient: an executive summary. Society of Critical Care Medicine

OBJECTIVE

The development of practice parameters for achieving sustained neuromuscular blockade in the adult critically ill patient for the purpose of guiding clinical practice.

PARTICIPANTS

A task force of more than 40 experts in disciplines related to the use of neuromuscular blocking agents in the intensive care unit was convened from the membership of the American College of Critical Care Medicine (ACCM) and the Society of Critical Care Medicine (SCCM).

EVIDENCE

The task force members provided the personal experience and determined the published literature (MEDLINE articles, textbooks, pharmacopeias, etc.) from which consensus would be sought. Published literature was reviewed and classified into one of four predetermined categories, according to study design and scientific value.

CONSENSUS PROCESS

The task force met several times as a whole, and numerous times in smaller groups by teleconference, over a 1-yr period to identify the pertinent literature and arrive at consensus recommendations for the whole task force to discuss. Consideration was given to the relationship between the weight of scientific information and the experts' viewpoints. Over the next year, draft documents were composed by a task force steering committee and debated by the task force members until consensus was reached by nominal group process. The task force draft was then reviewed, assessed, and edited by the Board of Regents of the ACCM. After steering committee approval, the draft document was reviewed and approved by the SCCM Council.

DATA SYNTHESIS

To facilitate rapid communication of the three recommendations contained within the complete and unabridged practice parameter document, an executive summary was prepared for publication by the ACCM Board of Regents, and this executive summary was approved by the task force steering committee and the SCCM Executive Council.

CONCLUSIONS

A consensus of experts provided three recommendations with supporting data for achieving sustained neuromuscular blockade in critically ill patients: a) pancuronium is the preferred neuromuscular blocking agent for most critically ill patients; b) vecuronium is the preferred neuromuscular blocking agent for those patients with cardiac disease or hemodynamic instability in whom tachycardia may be deleterious; c) patients receiving neuromuscular blocking agents should be appropriately assessed for the degree of blockade that is being sustained. This executive summary selectively presents supporting information and is not intended as a substitute for the complete document.