Comparison of train-of-four and best clinical assessment during continuous paralysis

Evaluation of Rocuronium Continuous Infusion in Critically Ill Patients During the COVID-19 Pandemic and Drug Shortages

Background: Limited data exist to support the use of rocuronium continuous infusions in the intensive care unit (ICU). Objective: To evaluate the dosing and monitoring of adult patients who received rocuronium for hypoxemic respiratory failure during the Coronavirus Disease 2019 (COVID-19) pandemic. Methods: This was a retrospective, single-center study from March 1, 2020 to May 31, 2020. We identified all adult patients admitted to any ICU who received rocuronium via continuous infusion. Patients were excluded if they received rocuronium for <6 hours. The main outcome of this study was to determine the median rocuronium maintenance continuous infusion rate in the ICU. Secondary outcomes of this study included the initial continuous infusion rate, duration of therapy, cumulative dose, frequency and median of rocuronium boluses, time to resolution of neuromuscular blockade, and the relationship between the hourly administration rates of rocuronium and train-of-four (TOF) assessments. Results: Seventy-one patients and 97 paralytic infusions were included. Fifty-nine patients (83%) were positive for SARS CoV-2. Of the 97 rocuronium infusions, the median dose at initiation was 3 (3-5) mcg/kg/min and duration of infusion was 45 (23.6-92.5) hours. The median continuous infusion maintenance rate was 4.3 (2.8-7.2) mcg/kg/min. There was a negligible correlation between the dose of rocuronium and the TOF results (r = .04). A total of 1775 TOFs were assessed, of which 46.2% were over-paralyzed, 35.7% well-paralyzed, and 18.1% under-paralyzed. Conclusions: The initial and maintenance infusion doses in our analysis were lower than what have been previously referenced.

Comparison of three cisatracurium dosing strategies in acute respiratory distress syndrome: A focus on drug utilization and improvement in oxygenation

Purpose

Three continuous dosing strategies of cisatracurium (CIS) for acute respiratory distress syndrome (ARDS) have been described in the literature. After implementation of a ventilator synchrony protocol (VSP), we sought to determine which continuous CIS dosing strategy utilized the least amount of drug without compromising efficacy.

Methods

We retrospectively reviewed patients with ARDS receiving continuous CIS from January 1, 2013 to December 31, 2018. We categorized patients into one of three dosing strategies: fixed dose (FD), titration based solely on train-of-four (TOF), or the VSP. We documented drug consumption and determined efficacy by comparing the change in PaO₂/FiO₂ ratio (P/F) and oxygenation index (OI) from baseline up to 48 h.

Results

A total of 1047 patients were screened, and 189 met inclusion criteria (VSP = 69, TOF = 99, FD = 21). Drug consumption (mg) was significantly lower in the VSP arm: 415 [IQR 318–528] compared to both the TOF: 665 [IQR 472–927] and the FD arms: 1730 [IQR 1695–1800], p < 0.001 for each. The change in P/F and OI from baseline were statistically equivalent at all time points.

Conclusion

Without impacting efficacy of gas exchange, a protocol using ventilator synchrony for CIS titration required significantly less drug compared to TOF-based titration and a fixed dosing regimen.

Neuromuscular Blockade Monitoring in Acute Respiratory Distress Syndrome: Randomized Controlled Trial of Clinical Assessment Alone or With Peripheral Nerve Stimulation

BACKGROUND

Whether train-of-four (TOF) monitoring is more effective than clinical monitoring to guide neuromuscular blockade (NMB) in patients with acute respiratory distress syndrome (ARDS) is unclear. We compared clinical monitoring alone or with TOF monitoring to guide atracurium dosage adjustment with respect to drug dose and respiratory parameters.

METHODS

From 2015 to 2016, we conducted a randomized controlled trial comparing clinical assessments every 2 hours with or without corrugator supercilii TOF monitoring every 4 hours in patients who developed ARDS (Pao2/Fio2 <150 mm Hg) in a cardiothoracic intensive care unit. The primary outcome was the cumulative atracurium dose (mg/kg/h). Secondary outcomes included respiratory parameters during the neuromuscular blockade.

RESULTS

A total of 38 patients in the clinical + TOF (C + TOF) group and 39 patients in the clinical (C) group were included in an intention-to-treat (ITT) analysis. The cumulative atracurium dose was higher in the C + TOF group (1.06 [0.75-1.30] vs 0.65 [0.60-0.89] mg/kg/h in the C group; P < .001) compared to C group, as well as the atracurium daily dose (C + TOF - C group mean difference = 0.256 mg/kg/h [95% confidence interval {CI}, 0.099-0.416], P = .026). Driving pressures during neuromuscular blocking agent (NMBA) administration did not differ between groups (P = .653). Intensive care unit (ICU) mortality was 22% in the C group and 27% in the C + TOF group (P = .786). Days on ventilation were 17 (8-26) in the C group and 16 (10-35) in the C + TOF group.

CONCLUSIONS

In patients with ARDS, adding TOF to clinical monitoring of neuromuscular blockade did not change ICU mortality or days on mechanical ventilation (MV) but did increase atracurium consumption when compared to clinical assessment alone. TOF monitoring may not be needed in all patients who receive neuromuscular blockade for ARDS.

The Implementation of Protocol-Based Utilization of Neuromuscular Blocking Agent Using Clinical Variables in Acute Respiratory Distress Syndrome Patients

Supplemental Digital Content is available in the text.

Objectives:

The recent conflicting data on the mortality benefit of neuromuscular blocking agents in acute respiratory distress syndrome and the potential adverse effects of continuous neuromuscular blocking agent necessitates that these medications should be used judiciously with dose reduction in mind. The aims of the study were to improve the process of care by provider education of neuromuscular blocking agent titration and monitoring and to determine the impact of clinical endpoint based neuromuscular blocking agent titration protocol.

Design:

We conducted a proof-of-concept historically controlled study of protocol-based intervention standardizing paralytic monitoring and titration using clinical variables. Education of the protocol was provided to ICU staff via bedside teaching and workshops. The primary outcomes were the time to reach goal paralysis and cumulative neuromuscular blocking agent dose. Secondary outcomes included maintenance of deeper sedation (Richmond Agitation and Sedation Scale –5) prior to neuromuscular blocking agent initiation, total time on mechanical ventilation, length of stay, and mortality.

Setting:

Medical ICU at a quaternary academic hospital between March 2019 and June 2020.

Patients:

Adult severe acute respiratory distress syndrome (Pao₂/Fio₂ <150) patients requiring neuromuscular blocking agent for greater than or equal to 12 hours. Eighty-two patients fulfilled inclusion criteria, 46 in the control group and 36 in the intervention group.

Interventions:

Education and implementation of standardized protocol.

Measurements and Main Results:

Compared with the control group, the time to reach goal paralysis in the intervention group was shorter (8.55 ± 9.4 vs 2.63 ± 5.9 hr; p < 0.0001) on significantly lower dose of cisatracurium (total dose 1,897.96 ± 1,241.0 vs 562.72 ± 546.7 mg; p < 0.0001 and the rate 5.84 ± 2.66 vs 1.99 ± 0.95 µg/kg/min; p < 0.0001). Deeper sedation was achieved at the time of initiation of neuromuscular blocking agent in the intervention arm (mean Richmond Agitation and Sedation Scale –3.3 ± 1.9 vs –4.3 ± 1.7; p = 0.015). There was no significant difference in total time on mechanical ventilation, length of ICU stay, length of hospital stay, and mortality between the two groups.

Conclusions:

Implementation of comprehensive education, standardization of sedation prior to neuromuscular blocking agent initiation, integration of clinical variables in determining paralysis achievement, and proper use of peripheral nerve stimulation served as optimal strategies for the titration and monitoring of neuromuscular blocking agent in acute respiratory distress syndrome. This reduced drug utilization while continuing to achieve benefit without causing adverse effects.

Neuromuscular blocking agents for acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is an acute inflammatory process that impairs the ability of the lungs to oxygenate thereby resulting in respiratory failure. Treatment of ARDS is often a multimodal approach using both nonpharmacologic and pharmacologic treatment strategies in addition to trying to reverse the underlying cause of ARDS. Neuromuscular blocking agents (NMBAs) have been prescribed to patients with ARDS as they are thought to decrease inflammation, oxygen consumption, and cardiac output and help facilitate ventilator synchrony. NMBAs have only been evaluated in patients with early, severe ARDS in three multicenter, randomized, controlled trials (n = 432), but have resulted in decreased inflammation and improved oxygenation, ventilator-free days, and mortality. Despite reports of NMBAs being associated with adverse effects like postparalytic quadriparesis, myopathy, and prolonged recovery, these effects have not been seen in patients receiving short courses of NMBAs for ARDS. A large multicenter, prospective, randomized, placebo-controlled trial is ongoing to confirm benefit of NMBAs in early, severe ARDS when adjusting for limitations of the previous studies. The current available literature suggests that 48 h of NMBA therapy in patients with early, severe ARDS improves mortality, without resulting in additional patient harm.

Use of neuromuscular blocking agents in acute respiratory distress syndrome

Acute respiratory distress syndrome is the result of an acute inflammatory response of the lungs, causing severe hypoxemia. A variety of therapeutic modalities have been extensively studied, with only a few demonstrating improvement in survival. Specifically, mechanical ventilation with use of low tidal volumes, prone positioning, and treatment with neuromuscular blocking agents have proven beneficial. This article focuses on the utilization of neuromuscular blocking agents in this entity. In particular, we briefly review the mechanism of action of neuromuscular blockades, the latest published evidence supporting their use in acute respiratory distress syndrome, and current recommendations for their utilization in clinical practice.

Design and Rationale of the Reevaluation of Systemic Early Neuromuscular Blockade Trial for Acute Respiratory Distress Syndrome

The Reevaluation of Systemic Early Neuromuscular Blockade (ROSE) trial is a multicenter, randomized trial designed to assess the efficacy and safety of early neuromuscular blockade in patients with moderate to severe acute respiratory distress syndrome. This document provides background for interpretation of the trial results, and highlights unique design approaches that may inform future trials of acute illness. We describe the process by which ROSE was chosen as the inaugural trial of the multidisciplinary Prevention and Early Treatment of Acute Lung Injury Network, provide the trial methodology using the Consolidated Standards of Reporting Trials framework, and discuss key design challenges and their resolution. Four key design issues proved challenging-feasibility, choice of sedation depth in the control group, impact of emphasizing early treatment on enrollment criteria and protocol execution, and choice of positive end-expiratory pressure strategy. We used literature, an iterative consensus model, and internal surveys of current practice to inform design choice. ROSE will provide definitive, Consolidated Standards of Reporting Trials adherent data on early neuromuscular blockade for future patients with acute respiratory distress syndrome. Our multidisciplinary approach to trial design may be of use to other trials of acute illness. Clinical trial registered with www.clinicaltrials.gov (NCT02509078).

How to reduce cisatracurium consumption in ARDS patients: the TOF-ARDS study

Background

Neuromuscular blocking agents (NMBAs) have been shown to improve the outcome of the most severely hypoxemic, acute respiratory distress syndrome (ARDS) patients. However, the recommended dosage as well as the necessity of monitoring the neuromuscular block is unknown. We aimed to evaluate the efficiency of a nurse-directed protocol of NMBA administration based on a train-of-four (TOF) assessment to ensure a profound neuromuscular block and decrease cisatracurium consumption compared to an elevated and constant dose regimen. A prospective open labeled study was conducted in two medical intensive care units of two French university hospitals. Consecutive ARDS patients with a PaO₂/FiO₂ ratio less than 120 with a PEEP ≥5 cm H₂O were included. Cisatracurium administration was driven by the nurses according to an algorithm based on TOF monitoring. The primary endpoint was cisatracurium consumption. The secondary endpoints included the quality of the neuromuscular block, the occurrence of adverse events, and the evolution of ventilatory and blood gas parameters.

Results

Thirty patients were included. NMBAs were used for 54 ± 30 h. According to this new algorithm, the initial dosage of cisatracurium was 11.8 ± 2 mg/h, and the final dosage was 14 ± 4 mg/h, which was significantly lower than in the ACURASYS study protocol (37.5 mg/h with a constant infusion rate (p < 0.001). The overall cisatracurium dose used was 700 ± 470 mg in comparison with 2040 ± 1119 mg for patients had received the ACURASYS dosage for the same period (p < 0.001). A profound neuromuscular block (TOF = 0, twitches at the ulnar site) was obtained from the first hour in 70% of patients. Modification of the cisatracurium dosage was not performed from the beginning to the end of the study in 60% of patients. Patient–ventilator asynchronies occurred in 4 patients.

Conclusion

A nurse-driven protocol based on TOF monitoring for NMBA administration in ARDS patients was able to decrease cisatracurium consumption without significantly affecting the quality of the neuromuscular block.

Clinical assessment and train-of-four measurements in critically ill patients treated with recommended doses of cisatracurium or atracurium for neuromuscular blockade: a prospective descriptive study

Background

Despite few studies, a monitoring of a neuromuscular blockade with a train of four (TOF) is recommended in intensive care unit (ICU). Our objective was to compare the results of ulnar and facial TOF measurements with an overall clinical assessment for neuromuscular blockade in ICU patients treated with recommended doses of atracurium or cisatracurium, including patients with acute respiratory disease syndrome (ARDS).

Methods

We prospectively included in two ICUs 119 patients, 94 with ARDS, who required a neuromuscular blockade for more than 24 h. Three levels of neuromuscular blockade were defined: “over-paralyzed” (TOF = 0), “well-paralyzed” (TOF = 1–2), and “under-paralyzed” (TOF = 3–4). Physicians blinded for TOF counts were asked to classify patients clinically as “over-paralyzed,” “well-paralyzed,” or “under-paralyzed”. Patients were assessed two times daily.

Results

For the whole population 996 ulnar and facial TOF measurements and clinical assessments were obtained (846 with cisatracurium and 150 with atracurium). Proportions of patients classified as over-paralyzed, well-paralyzed, and under-paralyzed based on TOF measurements and clinical assessments differed significantly (p < 0.0001). The number of observed agreements between clinical assessments and facial TOF measurements was of 19.08% (κ = 0.06) and of 17.37% with ulnar TOF measurements (κ = 0.04), while it was of 62.75% between ulnar and facial TOF measurements (κ = 0.45). Results were similar for cisatracurium and atracurium. Repeated facial TOF measurements performed on the first 4 days of mechanical ventilation in ARDS patients showed that the proportion of patients TOF = 1–2 was around 8% and did not vary significantly with time (p = 0.9), proportion of patients TOF = 3–4 increased from 24 to 40% (p = 0.01), proportion of patients TOF = 0 decreased from 71 to 53% (p = 0.005) while objectives for protective ventilation were achieved. Proportions of facial and ulnar TOF = 0 were significantly higher among patients with ICU-acquired weakness (ICU-AW) versus those who did not develop ICU-AW (51 vs. 40%, p = 0.03, and 76 vs. 62%, p = 0.006, respectively).

Conclusions

The study provides data on clinical and TOF monitoring of neuromuscular blockade, which are widely divergent in ICU patients receiving recommended doses of benzylisoquinoliniums.

Electronic supplementary material

The online version of this article (doi:10.1186/s13613-017-0234-0) contains supplementary material, which is available to authorized users.

Perceived safety and efficacy of neuromuscular blockers for acute respiratory distress syndrome among medical intensive care unit practitioners: A multicenter survey

PURPOSE

Neuromuscular blocking agents (NMBAs) are frequently used in patients with acute respiratory distress syndrome (ARDS). The purpose of this survey is to describe providers' knowledge and perceived efficacy and safety of NMBAs in patients with ARDS.

MATERIALS AND METHODS

We performed a prospective, multicenter survey of medical intensive care unit intensivists, fellows, nurse practitioners (NPs), physician's assistants (PAs), and pharmacists at 5 tertiary care centers between July 2012 and May 2013.

RESULTS

A total of 335 surveys were sent to providers, with a 47% response rate. Ninety-eight percent of providers correctly identified that NMBAs lack anxiolytic and analgesic properties. The effect of end-organ damage on NMBA clearance was less commonly identified by NPs/PAs for both hepatic (P=.0077) and renal (P=.0272) dysfunction compared with physicians. More NP/PAs identified the association of consciousness with the use of NMBAs than physicians (P=.047). Forty-two percent of prescribers reported always or frequently using continuous-infusion NMBAs in patients with severe ARDS, with 89% initiating NMBAs because of ventilator dyssynchrony. Prescribers perceived continuous NMBAs to be more effective than inhaled prostaglandins (74% vs 56%) in severe ARDS but less safe (45% vs 84%). Train of 4 was identified by 54% of prescribers as their primary method for titration.

CONCLUSION

Providers are knowledgeable about NMBAs, but educational opportunities exist. Perceptions about the efficacy and safety of NMBAs varied among prescribers, and inconsistencies existed in the prioritization of management strategies for ARDS.

Neuromuscular Blockade in the 21st Century Management of the Critically Ill Patient

Neuromuscular blockings agents (NMBAs) have a controversial role in the ventilatory and medical management of critical illness. The clinical concern surrounding NMBA-induced complications stems from evidence presented in the 2002 clinical practice guidelines, but new evidence from subsequent randomized trials and studies provides a more optimistic outlook about the application of NMBAs in the ICU. Furthermore, changes in the delivery of critical care, such as protocolized care pathways, minimizing or interrupting sedation, increased monitoring techniques, and overall improvements in reducing immobility, have created a modern, 21st century ICU environment whereby NMBAs may be administered safely. In this article we start with a review of the mechanism of action, side effects, and pharmacology of commonly used NMBAs. We then address the rationale for NMBA use for an expanding number of indications (endotracheal intubation, acute respiratory distress syndrome, status asthmaticus, increased intracranial and intra-abdominal pressure, and therapeutic hypothermia after cardiac arrest), with an emphasis on NMBA use in facilitating lung-protective ventilation for respiratory failure. We end with an appraisal over the importance of monitoring depth of paralysis and the concerns of complications, such as prolonged skeletal muscle weakness. In the context of adequate sedation and analgesia, monitored NMBA use (continuous or bolus administration) can be considered for the small number of clinical indications in critically ill patients for which evidence currently exists.

Association Between Train-of-Four Values and Gas Exchange Indices in Moderate to Severe Acute Respiratory Distress Syndrome

BACKGROUND

Acute respiratory distress syndrome (ARDS) is associated with a mortality rate of approximately 40%. Neuromuscular blockade is associated with an improvement in oxygenation and a reduction in mortality in ARDS.

OBJECTIVE

The goal of this evaluation was to determine if the depth of paralysis, determined by train-of-four (TOF) monitoring, correlates with gas exchange in moderate to severe ARDS.

METHODS

This was a retrospective review of moderate to severe ARDS patients who were prescribed >12 hours of continuous infusion cisatracurium between January 1, 2013, and December 31, 2014, with a PaO₂:FiO₂ ratio <150 and documented TOF and arterial blood gases. Patients were evaluated for inclusion at 12, 24, and 48 hours after initiation of neuromuscular blockade.

RESULTS

A total of 378 patients were screened for inclusion, with 107 evaluable patients meeting criteria at baseline. Poor correlation existed between TOF and oxygenation index (OI) at 12 (τ = 0.03), 24 (τ = 0.15) and 48 hours (τ = 0.08). When controlling for proning and baseline OI, the depth of paralysis did not have a significant effect on OI at 12, 24, or 48 hours.

CONCLUSIONS

This evaluation demonstrates that the use of TOF monitoring for neuromuscular blockade does not correlate with gas exchange markers in moderate to severe ARDS.

Surviving sepsis campaign: international guidelines for management of severe sepsis and septic shock: 2012

OBJECTIVE

To provide an update to the "Surviving Sepsis Campaign Guidelines for Management of Severe Sepsis and Septic Shock," last published in 2008.

DESIGN

A consensus committee of 68 international experts representing 30 international organizations was convened. Nominal groups were assembled at key international meetings (for those committee members attending the conference). A formal conflict of interest policy was developed at the onset of the process and enforced throughout. The entire guidelines process was conducted independent of any industry funding. A stand-alone meeting was held for all subgroup heads, co- and vice-chairs, and selected individuals. Teleconferences and electronic-based discussion among subgroups and among the entire committee served as an integral part of the development.

METHODS

The authors were advised to follow the principles of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to guide assessment of quality of evidence from high (A) to very low (D) and to determine the strength of recommendations as strong (1) or weak (2). The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasized. Some recommendations were ungraded (UG). Recommendations were classified into three groups: 1) those directly targeting severe sepsis; 2) those targeting general care of the critically ill patient and considered high priority in severe sepsis; and 3) pediatric considerations.

RESULTS

Key recommendations and suggestions, listed by category, include: early quantitative resuscitation of the septic patient during the first 6 hrs after recognition (1C); blood cultures before antibiotic therapy (1C); imaging studies performed promptly to confirm a potential source of infection (UG); administration of broad-spectrum antimicrobials therapy within 1 hr of recognition of septic shock (1B) and severe sepsis without septic shock (1C) as the goal of therapy; reassessment of antimicrobial therapy daily for de-escalation, when appropriate (1B); infection source control with attention to the balance of risks and benefits of the chosen method within 12 hrs of diagnosis (1C); initial fluid resuscitation with crystalloid (1B) and consideration of the addition of albumin in patients who continue to require substantial amounts of crystalloid to maintain adequate mean arterial pressure (2C) and the avoidance of hetastarch formulations (1C); initial fluid challenge in patients with sepsis-induced tissue hypoperfusion and suspicion of hypovolemia to achieve a minimum of 30 mL/kg of crystalloids (more rapid administration and greater amounts of fluid may be needed in some patients) (1C); fluid challenge technique continued as long as hemodynamic improvement, as based on either dynamic or static variables (UG); norepinephrine as the first-choice vasopressor to maintain mean arterial pressure ≥ 65 mm Hg (1B); epinephrine when an additional agent is needed to maintain adequate blood pressure (2B); vasopressin (0.03 U/min) can be added to norepinephrine to either raise mean arterial pressure to target or to decrease norepinephrine dose but should not be used as the initial vasopressor (UG); dopamine is not recommended except in highly selected circumstances (2C); dobutamine infusion administered or added to vasopressor in the presence of a) myocardial dysfunction as suggested by elevated cardiac filling pressures and low cardiac output, or b) ongoing signs of hypoperfusion despite achieving adequate intravascular volume and adequate mean arterial pressure (1C); avoiding use of intravenous hydrocortisone in adult septic shock patients if adequate fluid resuscitation and vasopressor therapy are able to restore hemodynamic stability (2C); hemoglobin target of 7-9 g/dL in the absence of tissue hypoperfusion, ischemic coronary artery disease, or acute hemorrhage (1B); low tidal volume (1A) and limitation of inspiratory plateau pressure (1B) for acute respiratory distress syndrome (ARDS); application of at least a minimal amount of positive end-expiratory pressure (PEEP) in ARDS (1B); higher rather than lower level of PEEP for patients with sepsis-induced moderate or severe ARDS (2C); recruitment maneuvers in sepsis patients with severe refractory hypoxemia due to ARDS (2C); prone positioning in sepsis-induced ARDS patients with a PaO2/FIO2 ratio of ≤ 100 mm Hg in facilities that have experience with such practices (2C); head-of-bed elevation in mechanically ventilated patients unless contraindicated (1B); a conservative fluid strategy for patients with established ARDS who do not have evidence of tissue hypoperfusion (1C); protocols for weaning and sedation (1A); minimizing use of either intermittent bolus sedation or continuous infusion sedation targeting specific titration endpoints (1B); avoidance of neuromuscular blockers if possible in the septic patient without ARDS (1C); a short course of neuromuscular blocker (no longer than 48 hrs) for patients with early ARDS and a Pao2/Fio2 < 150 mm Hg (2C); a protocolized approach to blood glucose management commencing insulin dosing when two consecutive blood glucose levels are > 180 mg/dL, targeting an upper blood glucose ≤ 180 mg/dL (1A); equivalency of continuous veno-venous hemofiltration or intermittent hemodialysis (2B); prophylaxis for deep vein thrombosis (1B); use of stress ulcer prophylaxis to prevent upper gastrointestinal bleeding in patients with bleeding risk factors (1B); oral or enteral (if necessary) feedings, as tolerated, rather than either complete fasting or provision of only intravenous glucose within the first 48 hrs after a diagnosis of severe sepsis/septic shock (2C); and addressing goals of care, including treatment plans and end-of-life planning (as appropriate) (1B), as early as feasible, but within 72 hrs of intensive care unit admission (2C). Recommendations specific to pediatric severe sepsis include: therapy with face mask oxygen, high flow nasal cannula oxygen, or nasopharyngeal continuous PEEP in the presence of respiratory distress and hypoxemia (2C), use of physical examination therapeutic endpoints such as capillary refill (2C); for septic shock associated with hypovolemia, the use of crystalloids or albumin to deliver a bolus of 20 mL/kg of crystalloids (or albumin equivalent) over 5 to 10 mins (2C); more common use of inotropes and vasodilators for low cardiac output septic shock associated with elevated systemic vascular resistance (2C); and use of hydrocortisone only in children with suspected or proven "absolute"' adrenal insufficiency (2C).

CONCLUSIONS

Strong agreement existed among a large cohort of international experts regarding many level 1 recommendations for the best care of patients with severe sepsis. Although a significant number of aspects of care have relatively weak support, evidence-based recommendations regarding the acute management of sepsis and septic shock are the foundation of improved outcomes for this important group of critically ill patients.

Pharmacotherapy for acute respiratory distress syndrome

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) represent a continuum of a clinical syndrome of respiratory failure due to refractory hypoxia. Acute respiratory distress syndrome is differentiated from ALI by a greater degree of hypoxemia and is associated with higher morbidity and mortality. The mortality for ARDS ranges from 22-41%, with survivors usually requiring long-term rehabilitation to regain normal physiologic function. Numerous pharmacologic therapies have been studied for prevention and treatment of ARDS; however, studies demonstrating clear clinical benefit for ARDS-related mortality and morbidity are limited. In this focused review, controversial pharmacologic therapies that have demonstrated, at minimum, a modest clinical benefit are discussed. Three pharmacologic treatment strategies are reviewed in detail: corticosteroids, fluid management, and neuromuscular blocking agents. Use of corticosteroids to attenuate inflammation remains controversial. Available evidence does not support early administration of corticosteroids. Additionally, administration after 14 days of disease onset is strongly discouraged. A liberal fluid strategy during the early phase of comorbid septic shock, balanced with a conservative fluid strategy in patients with ALI or ARDS during the postresuscitation phase, is the optimum approach for fluid management. Available evidence supports an early, short course of continuous-infusion cisatracurium in patients presenting with severe ARDS. Evidence of safe and effective pharmacologic therapies for ARDS is limited, and clinicians must be knowledgeable about the areas of controversies to determine application to patient care.

Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock, 2012

OBJECTIVE

To provide an update to the "Surviving Sepsis Campaign Guidelines for Management of Severe Sepsis and Septic Shock," last published in 2008.

DESIGN

A consensus committee of 68 international experts representing 30 international organizations was convened. Nominal groups were assembled at key international meetings (for those committee members attending the conference). A formal conflict of interest policy was developed at the onset of the process and enforced throughout. The entire guidelines process was conducted independent of any industry funding. A stand-alone meeting was held for all subgroup heads, co- and vice-chairs, and selected individuals. Teleconferences and electronic-based discussion among subgroups and among the entire committee served as an integral part of the development.

METHODS

The authors were advised to follow the principles of the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to guide assessment of quality of evidence from high (A) to very low (D) and to determine the strength of recommendations as strong (1) or weak (2). The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasized. Recommendations were classified into three groups: (1) those directly targeting severe sepsis; (2) those targeting general care of the critically ill patient and considered high priority in severe sepsis; and (3) pediatric considerations.

RESULTS

Key recommendations and suggestions, listed by category, include: early quantitative resuscitation of the septic patient during the first 6 h after recognition (1C); blood cultures before antibiotic therapy (1C); imaging studies performed promptly to confirm a potential source of infection (UG); administration of broad-spectrum antimicrobials therapy within 1 h of the recognition of septic shock (1B) and severe sepsis without septic shock (1C) as the goal of therapy; reassessment of antimicrobial therapy daily for de-escalation, when appropriate (1B); infection source control with attention to the balance of risks and benefits of the chosen method within 12 h of diagnosis (1C); initial fluid resuscitation with crystalloid (1B) and consideration of the addition of albumin in patients who continue to require substantial amounts of crystalloid to maintain adequate mean arterial pressure (2C) and the avoidance of hetastarch formulations (1B); initial fluid challenge in patients with sepsis-induced tissue hypoperfusion and suspicion of hypovolemia to achieve a minimum of 30 mL/kg of crystalloids (more rapid administration and greater amounts of fluid may be needed in some patients (1C); fluid challenge technique continued as long as hemodynamic improvement is based on either dynamic or static variables (UG); norepinephrine as the first-choice vasopressor to maintain mean arterial pressure ≥65 mmHg (1B); epinephrine when an additional agent is needed to maintain adequate blood pressure (2B); vasopressin (0.03 U/min) can be added to norepinephrine to either raise mean arterial pressure to target or to decrease norepinephrine dose but should not be used as the initial vasopressor (UG); dopamine is not recommended except in highly selected circumstances (2C); dobutamine infusion administered or added to vasopressor in the presence of (a) myocardial dysfunction as suggested by elevated cardiac filling pressures and low cardiac output, or (b) ongoing signs of hypoperfusion despite achieving adequate intravascular volume and adequate mean arterial pressure (1C); avoiding use of intravenous hydrocortisone in adult septic shock patients if adequate fluid resuscitation and vasopressor therapy are able to restore hemodynamic stability (2C); hemoglobin target of 7-9 g/dL in the absence of tissue hypoperfusion, ischemic coronary artery disease, or acute hemorrhage (1B); low tidal volume (1A) and limitation of inspiratory plateau pressure (1B) for acute respiratory distress syndrome (ARDS); application of at least a minimal amount of positive end-expiratory pressure (PEEP) in ARDS (1B); higher rather than lower level of PEEP for patients with sepsis-induced moderate or severe ARDS (2C); recruitment maneuvers in sepsis patients with severe refractory hypoxemia due to ARDS (2C); prone positioning in sepsis-induced ARDS patients with a PaO (2)/FiO (2) ratio of ≤100 mm Hg in facilities that have experience with such practices (2C); head-of-bed elevation in mechanically ventilated patients unless contraindicated (1B); a conservative fluid strategy for patients with established ARDS who do not have evidence of tissue hypoperfusion (1C); protocols for weaning and sedation (1A); minimizing use of either intermittent bolus sedation or continuous infusion sedation targeting specific titration endpoints (1B); avoidance of neuromuscular blockers if possible in the septic patient without ARDS (1C); a short course of neuromuscular blocker (no longer than 48 h) for patients with early ARDS and a PaO (2)/FI O (2) <150 mm Hg (2C); a protocolized approach to blood glucose management commencing insulin dosing when two consecutive blood glucose levels are >180 mg/dL, targeting an upper blood glucose ≤180 mg/dL (1A); equivalency of continuous veno-venous hemofiltration or intermittent hemodialysis (2B); prophylaxis for deep vein thrombosis (1B); use of stress ulcer prophylaxis to prevent upper gastrointestinal bleeding in patients with bleeding risk factors (1B); oral or enteral (if necessary) feedings, as tolerated, rather than either complete fasting or provision of only intravenous glucose within the first 48 h after a diagnosis of severe sepsis/septic shock (2C); and addressing goals of care, including treatment plans and end-of-life planning (as appropriate) (1B), as early as feasible, but within 72 h of intensive care unit admission (2C). Recommendations specific to pediatric severe sepsis include: therapy with face mask oxygen, high flow nasal cannula oxygen, or nasopharyngeal continuous PEEP in the presence of respiratory distress and hypoxemia (2C), use of physical examination therapeutic endpoints such as capillary refill (2C); for septic shock associated with hypovolemia, the use of crystalloids or albumin to deliver a bolus of 20 mL/kg of crystalloids (or albumin equivalent) over 5-10 min (2C); more common use of inotropes and vasodilators for low cardiac output septic shock associated with elevated systemic vascular resistance (2C); and use of hydrocortisone only in children with suspected or proven "absolute"' adrenal insufficiency (2C).

CONCLUSIONS

Strong agreement existed among a large cohort of international experts regarding many level 1 recommendations for the best care of patients with severe sepsis. Although a significant number of aspects of care have relatively weak support, evidence-based recommendations regarding the acute management of sepsis and septic shock are the foundation of improved outcomes for this important group of critically ill patients.

Current therapeutic uses, pharmacology, and clinical considerations of neuromuscular blocking agents for critically ill adults

OBJECTIVE

To summarize literature describing use of neuromuscular blocking agents (NMBAs) for common critical care indications and provide a review of NMBA pharmacology, pharmacokinetics, dosing, drug interactions, monitoring, complications, and reversal.

DATA SOURCES

Searches of MEDLINE (1975-May 2011), EMBASE (1980-May 2011), and Cumulative Index to Nursing and Allied Health Literature (1981-May 2011) were conducted to identify observational and interventional studies evaluating the efficacy or safety of NMBAs for management of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), status asthmaticus, elevated intracranial pressure (ICP), and therapeutic hypothermia.

STUDY SELECTION AND DATA EXTRACTION

We excluded case reports, animal- or laboratory-based studies, trials describing NMBA use during rapid sequence intubation or in the operating room, and studies published in languages other than English or French.

DATA SYNTHESIS

Clinical applications of NMBAs in intensive care include, but are not limited to, immobilizing patients for procedural interventions, decreasing oxygen consumption, facilitating mechanical ventilation, reducing intracranial pressure, preventing shivering, and management of tetanus. Recent data on ARDS demonstrated that early application of NMBAs improved adjusted 90-day survival for patients with severe lung injury. These results may lead to increased use of these drugs. While emerging data support the use of cisatracurium in select patients with ALI/ARDS, current literature does not support the use of one NMBA over another for other critical care indications. Cisatracurium may be kinetically preferred for patients with organ dysfunction. Close monitoring with peripheral nerve stimulation is recommended with sustained use of NMBAs to avoid drug accumulation and minimize the risk for adverse drug events. Reversal of paralysis is achieved by discontinuing therapy or, rarely, the use of anticholinesterases.

CONCLUSIONS

NMBAs are high-alert medications used to manage critically ill patients. New data are available regarding the use of these agents for treatment of ALI/ARDS and status asthmaticus, management of elevated ICP, and provision of therapeutic hypothermia after cardiac arrest. To improve outcomes and promote patient safety, intensive care unit team members should have a thorough knowledge of this class of medications.

Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock: 2008

OBJECTIVE

To provide an update to the original Surviving Sepsis Campaign clinical management guidelines, "Surviving Sepsis Campaign Guidelines for Management of Severe Sepsis and Septic Shock," published in 2004.

DESIGN

Modified Delphi method with a consensus conference of 55 international experts, several subsequent meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee. This process was conducted independently of any industry funding.

METHODS

We used the Grades of Recommendation, Assessment, Development and Evaluation (GRADE) system to guide assessment of quality of evidence from high (A) to very low (D) and to determine the strength of recommendations. A strong recommendation (1) indicates that an intervention's desirable effects clearly outweigh its undesirable effects (risk, burden, cost) or clearly do not. Weak recommendations (2) indicate that the tradeoff between desirable and undesirable effects is less clear. The grade of strong or weak is considered of greater clinical importance than a difference in letter level of quality of evidence. In areas without complete agreement, a formal process of resolution was developed and applied. Recommendations are grouped into those directly targeting severe sepsis, recommendations targeting general care of the critically ill patient that are considered high priority in severe sepsis, and pediatric considerations.

RESULTS

Key recommendations, listed by category, include early goal-directed resuscitation of the septic patient during the first 6 hrs after recognition (1C); blood cultures before antibiotic therapy (1C); imaging studies performed promptly to confirm potential source of infection (1C); administration of broad-spectrum antibiotic therapy within 1 hr of diagnosis of septic shock (1B) and severe sepsis without septic shock (1D); reassessment of antibiotic therapy with microbiology and clinical data to narrow coverage, when appropriate (1C); a usual 7-10 days of antibiotic therapy guided by clinical response (1D); source control with attention to the balance of risks and benefits of the chosen method (1C); administration of either crystalloid or colloid fluid resuscitation (1B); fluid challenge to restore mean circulating filling pressure (1C); reduction in rate of fluid administration with rising filing pressures and no improvement in tissue perfusion (1D); vasopressor preference for norepinephrine or dopamine to maintain an initial target of mean arterial pressure > or = 65 mm Hg (1C); dobutamine inotropic therapy when cardiac output remains low despite fluid resuscitation and combined inotropic/vasopressor therapy (1C); stress-dose steroid therapy given only in septic shock after blood pressure is identified to be poorly responsive to fluid and vasopressor therapy (2C); recombinant activated protein C in patients with severe sepsis and clinical assessment of high risk for death (2B except 2C for postoperative patients). In the absence of tissue hypoperfusion, coronary artery disease, or acute hemorrhage, target a hemoglobin of 7-9 g/dL (1B); a low tidal volume (1B) and limitation of inspiratory plateau pressure strategy (1C) for acute lung injury (ALI)/acute respiratory distress syndrome (ARDS); application of at least a minimal amount of positive end-expiratory pressure in acute lung injury (1C); head of bed elevation in mechanically ventilated patients unless contraindicated (1B); avoiding routine use of pulmonary artery catheters in ALI/ARDS (1A); to decrease days of mechanical ventilation and ICU length of stay, a conservative fluid strategy for patients with established ALI/ARDS who are not in shock (1C); protocols for weaning and sedation/analgesia (1B); using either intermittent bolus sedation or continuous infusion sedation with daily interruptions or lightening (1B); avoidance of neuromuscular blockers, if at all possible (1B); institution of glycemic control (1B), targeting a blood glucose < 150 mg/dL after initial stabilization (2C); equivalency of continuous veno-veno hemofiltration or intermittent hemodialysis (2B); prophylaxis for deep vein thrombosis (1A); use of stress ulcer prophylaxis to prevent upper gastrointestinal bleeding using H2 blockers (1A) or proton pump inhibitors (1B); and consideration of limitation of support where appropriate (1D). Recommendations specific to pediatric severe sepsis include greater use of physical examination therapeutic end points (2C); dopamine as the first drug of choice for hypotension (2C); steroids only in children with suspected or proven adrenal insufficiency (2C); and a recommendation against the use of recombinant activated protein C in children (1B).

CONCLUSIONS

There was strong agreement among a large cohort of international experts regarding many level 1 recommendations for the best current care of patients with severe sepsis. Evidenced-based recommendations regarding the acute management of sepsis and septic shock are the first step toward improved outcomes for this important group of critically ill patients.

Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock: 2008

OBJECTIVE

To provide an update to the original Surviving Sepsis Campaign clinical management guidelines, "Surviving Sepsis Campaign guidelines for management of severe sepsis and septic shock," published in 2004.

DESIGN

Modified Delphi method with a consensus conference of 55 international experts, several subsequent meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee. This process was conducted independently of any industry funding.

METHODS

We used the GRADE system to guide assessment of quality of evidence from high (A) to very low (D) and to determine the strength of recommendations. A strong recommendation indicates that an intervention's desirable effects clearly outweigh its undesirable effects (risk, burden, cost), or clearly do not. Weak recommendations indicate that the tradeoff between desirable and undesirable effects is less clear. The grade of strong or weak is considered of greater clinical importance than a difference in letter level of quality of evidence. In areas without complete agreement, a formal process of resolution was developed and applied. Recommendations are grouped into those directly targeting severe sepsis, recommendations targeting general care of the critically ill patient that are considered high priority in severe sepsis, and pediatric considerations.

RESULTS

Key recommendations, listed by category, include: early goal-directed resuscitation of the septic patient during the first 6 hrs after recognition (1C); blood cultures prior to antibiotic therapy (1C); imaging studies performed promptly to confirm potential source of infection (1C); administration of broad-spectrum antibiotic therapy within 1 hr of diagnosis of septic shock (1B) and severe sepsis without septic shock (1D); reassessment of antibiotic therapy with microbiology and clinical data to narrow coverage, when appropriate (1C); a usual 7-10 days of antibiotic therapy guided by clinical response (1D); source control with attention to the balance of risks and benefits of the chosen method (1C); administration of either crystalloid or colloid fluid resuscitation (1B); fluid challenge to restore mean circulating filling pressure (1C); reduction in rate of fluid administration with rising filing pressures and no improvement in tissue perfusion (1D); vasopressor preference for norepinephrine or dopamine to maintain an initial target of mean arterial pressure > or = 65 mm Hg (1C); dobutamine inotropic therapy when cardiac output remains low despite fluid resuscitation and combined inotropic/vasopressor therapy (1C); stress-dose steroid therapy given only in septic shock after blood pressure is identified to be poorly responsive to fluid and vasopressor therapy (2C); recombinant activated protein C in patients with severe sepsis and clinical assessment of high risk for death (2B except 2C for post-operative patients). In the absence of tissue hypoperfusion, coronary artery disease, or acute hemorrhage, target a hemoglobin of 7-9 g/dL (1B); a low tidal volume (1B) and limitation of inspiratory plateau pressure strategy (1C) for acute lung injury (ALI)/acute respiratory distress syndrome (ARDS); application of at least a minimal amount of positive end-expiratory pressure in acute lung injury (1C); head of bed elevation in mechanically ventilated patients unless contraindicated (1B); avoiding routine use of pulmonary artery catheters in ALI/ARDS (1A); to decrease days of mechanical ventilation and ICU length of stay, a conservative fluid strategy for patients with established ALI/ARDS who are not in shock (1C); protocols for weaning and sedation/analgesia (1B); using either intermittent bolus sedation or continuous infusion sedation with daily interruptions or lightening (1B); avoidance of neuromuscular blockers, if at all possible (1B); institution of glycemic control (1B) targeting a blood glucose < 150 mg/dL after initial stabilization ( 2C ); equivalency of continuous veno-veno hemofiltration or intermittent hemodialysis (2B); prophylaxis for deep vein thrombosis (1A); use of stress ulcer prophylaxis to prevent upper GI bleeding using H2 blockers (1A) or proton pump inhibitors (1B); and consideration of limitation of support where appropriate (1D). Recommendations specific to pediatric severe sepsis include: greater use of physical examination therapeutic end points (2C); dopamine as the first drug of choice for hypotension (2C); steroids only in children with suspected or proven adrenal insufficiency (2C); a recommendation against the use of recombinant activated protein C in children (1B).

CONCLUSION

There was strong agreement among a large cohort of international experts regarding many level 1 recommendations for the best current care of patients with severe sepsis. Evidenced-based recommendations regarding the acute management of sepsis and septic shock are the first step toward improved outcomes for this important group of critically ill patients.

Use of Sedatives and Neuromuscular Blockers in a Cohort of Patients Receiving Mechanical Ventilation

OBJECTIVE

To describe the use of sedatives and neuromuscular blocking agents (NMBs) and their impact in outcome in an international cohort of patients receiving mechanical ventilation.

METHODS

We analyzed the database of a prospective, multicenter cohort of 5,183 adult patients who received mechanical ventilation for > 12 h. We considered that a patient received a given agent when it was administered for at least 3 h in a 24-h period.

RESULTS

A total of 3,540 patients (68%; 95% confidence interval [CI], 67 to 69%) received a sedative at any time while receiving mechanical ventilation. The median number of days of use was 3 (interquartile range [IQR], 2 to 6 days). The persistent use of sedative was associated with more days of mechanical ventilation (median, 4 days [IQR, 2 to 8 days], vs 3 days [IQR, 2 to 4 days] in patients who did not receive sedatives [p < 0.001]); more weaning days (median, 2 days [IQR, 1 to 3 days], vs 2 days [IQR, 1 to 5 days] in patients who did not receive sedatives [p < 0.001]); and longer length of stay in the ICU (median, 8 days [IQR, 5 to 15 days], vs 5 days [IQR, 3 to 9 days] in patients who did not receive sedatives [p < 0.001]). Six hundred eighty-six patients (13%; 95% CI, 12 to 14%) received an NMB for at least 1 day. The median number of days of use was 2 (IQR, 1 to 4 days). The administration of an NMB was independently related with age, a normal previous functional status, main reason of mechanical ventilation (patients with ARDS received more NMBs), and with patient management (patients requiring permissive hypercapnia, prone position, high level of positive end-expiratory pressure, and high airways pressure).

CONCLUSIONS

The use of sedatives is very common, and their use is associated with a longer duration of mechanical ventilation, weaning time, and stay in the ICU. NMBs are used in 13% of the patients and are associated with longer duration of mechanical ventilation, weaning time, stay in the ICU, and higher mortality.

Bispectral Index Monitoring in the Intensive Care Unit Provides More Signal Than Noise

The bispectral index (BIS) is processed electroencephalographic technology used in concert with clinical evaluations to objectively evaluate a patient's level of consciousness and probability of recall. Although the BIS has been extensively studied in the operating room setting, differences in patient populations, goals of treatment, and the environments themselves necessitate the development of BIS data specific to the intensive care unit. Data have evolved over the last several years, but for many reasons, the results and conclusions have varied. Yet within the data are important consistencies that help define the usefulness of BIS in patients who cannot be evaluated with subjective assessment tools such as the Sedation-Agitation Scale or the Richmond Agitation-Sedation Scale. Some of these patients cannot be evaluated with such tools because they lack motor responsiveness due to therapeutic paralysis or because they are receiving deep sedation. Bispectral index scores that are higher than expected in clinically sedated patients can often be traced to electromyographic activity or to the possibility of inadequate sedation and analgesia. The BIS must not be regarded as the sole indicator of level of consciousness, but should be used as part of an integrated approach to the evaluation of carefully selected patients with critical illness.

Sedation, analgesia, and neuromuscular blockade for high-frequency oscillatory ventilation

OBJECTIVE

To provide a comprehensive review of the issue related to the administration of sedative, analgesic, and neuromuscular blocking agents (NMBA) to patients who are receiving ventilatory support for acute respiratory distress syndrome (ARDS) with high-frequency oscillatory ventilation.

RESULTS

Sedative, analgesic, and NMBA are used with great frequency in patients with severe ARDS who are undergoing high-frequency oscillatory ventilation. In particular, the use of NMBA has been higher than for other ARDS populations. Important considerations for effective treatment include careful patient evaluation, patient-based medication selection, identification of treatment goals with periodic re-assessment, titration of medications to objective parameters such as sedation scales and peripheral nerve stimulation, use of intermittent therapy when feasible, implementation of drug interruption strategies, and discontinuation of medications at the earliest possible time. It is important to recognize that patients evolve from severe ARDS through phases of recovery to the resolution of respiratory failure and that ventilatory management, as well as sedative and related medication requirements, will vary markedly over the course of this process.

CONCLUSIONS

A multidisciplinary, structured approach that is based on the considerations described should help achieve optimal results in this challenging patient population.

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.

A prospective randomized comparison of train-of-four monitoring and clinical assessment during continuous ICU cisatracurium paralysis

STUDY PURPOSE

Train-of-four (TOF) monitoring is often recommended during the continuous use of neuromuscular blockade (NMB) [paralysis] in the ICU. Prior study results are conflicting regarding the benefits of TOF monitoring.

DESIGN

Thirty patients in the medical ICU were randomized to TOF monitoring (n = 16) or to clinical assessment (n = 14) during continuous cisatracurium infusion. TOF monitoring was done at least every 4 h, with the goal being maintenance of one to two twitches. Statistical analysis was performed by two-tailed, unpaired t test (with Bonferroni correction for multiple comparisons), chi(2), and Fisher exact test, with p < 0.05 considered significant. Given a power of 80%, and the variance seen in the two groups, we estimate that the sample size used is sufficient to detect a change of > or = 60 min between groups for recovery time.

RESULTS

The mean recovery time after cessation of paralytics was no different between TOF and clinical assessment (45 +/- 7 min vs 38 +/- 10 min, respectively [mean +/- SEM]). No differences were noted for mean APACHE (acute physiology and chronic health evaluation) II entry scores, glomerular filtration rates, or use of corticosteroids. No significant differences were noted between TOF monitoring and clinical assessment in mean total paralysis time (4,118 +/- 1,012 min vs 3,188 +/- 705 min, respectively), mean total cisatracurium dose (920 +/- 325 mg vs 715 +/- 167 mg), or dosage (2.3 +/- 0.2 microg/kg/min vs 2.9 +/- 0.2 microg/kg/min).

CONCLUSIONS

TOF monitoring does not lead to improved recovery time or lower cisatracurium dosing compared with monitoring by clinical assessment. We conclude that TOF monitoring is unnecessary, and careful titration of the neuromuscular blocking agent by clinical assessment alone is sufficient in patients undergoing continuous cisatracurium NMB.

Effect of neuromuscular blocking agents on gas exchange in patients presenting with acute respiratory distress syndrome*

OBJECTIVE

To evaluate the effects of a 48-hr neuromuscular blocking agents (NMBA) infusion on gas exchange over a 120-hr time period in patients with acute respiratory distress syndrome.

DESIGN

Multiple center, prospective, controlled, and randomized trial.

SETTING

Four adult medical or mixed medical-surgical intensive care units.

PATIENTS

A total of 56 patients with acute respiratory distress syndrome with a PaO2/FiO2 ratio of <150 at a positive end-expiratory pressure of > or =5 cm H2O.

INTERVENTIONS

After randomization, patients received either conventional therapy without NMBA (control group) or conventional therapy plus NMBA for the next 48 hrs. The initial ventilator mode was volume-assist/control. The ventilator remained on assist-control mode throughout the initial 48-hr period in both groups. Tidal volume was 6-8 mL/kg ideal body weight.

MEASUREMENTS AND MAIN RESULTS

When analyzed for the entire 120 hrs, there was a significant effect of the NMBA on the course of PaO2/FiO2 ratio (p =.021). Separate comparisons at each time point indicated that patients randomized to the NMBA group had a higher PaO2/FiO2 at 48, 96, and 120 hrs after randomization. Moreover, a decrease of positive end-expiratory pressure (p =.036) was only found in the NMBA group. Two-way repeated-measures analysis of variance exhibited a decrease in positive end-expiratory pressure over time (p =.036). Concerning short-term effects, there was no modification of PaO2/FiO2 ratio 1 hr after randomization in either group. Only one patient (from the control group) developed pneumothorax.

CONCLUSIONS

Use of NMBA during a 48-hr period in patients with acute respiratory distress syndrome is associated with a sustained improvement in oxygenation.

An algorithm for train-of-four monitoring in patients receiving continuous neuromuscular blocking agents

Neuromuscular blocking agents (NMBA) are increasingly being used in the management of critically ill patients. These medications are used to facilitate mechanical ventilation. Strange and colleagues estimated that only 4% of intensive care units utilize train-of-four (TOF) monitoring on a regular basis and that 70% never use this type of monitoring. The ease of use and low cost of the equipment lends itself to the increasingly frequent recommendations for this type of monitoring. Although unwilling to go so far as to establish this as a standard of care, the American College of Critical Care Medicine of the Society of Critical Care Medicine released an executive summary recommending train-of-four monitoring for patients receiving continuous or sustained NMBAs. This protocol and algorithm was developed to facilitate the objective monitoring of patients receiving continuous NMBAs.

Pharmacodynamics and atracurium and laudanosine concentrations during a fixed continuous infusion of atracurium in mechanically ventilated patients with acute respiratory distress syndrome

The present study was designed to assess the pharmacodynamics and the plasma levels of atracurium and laudanosine found during a 72-hour fixed rate infusion of atracurium in acute respiratory distress syndrome patients without renal or liver failure. Nine sedated and mechanically ventilated acute respiratory distress syndrome patients without renal or liver failure were paralysed with a bolus of atracurium (1 mg x kg(-1)) followed by a 72-hour continuous infusion (1 mg x kg(-1) x h(-1)). The count of train-of-four (TOF) and TOF ratio were monitored by an accelerograph until full neuromuscular recovery (T4/T1 > or = 0.7). Atracurium and laudanosine concentrations were measured from the onset to four days after cessation of the infusion. An electroencephalogram was recorded daily. Analysis showed that TOF count was always < or = 3 until cessation of the infusion. Following cessation, neuromuscular recovery occurred between 31 and 96 minutes (median value = 45 min). The highest atracurium and laudanosine concentrations ranged from 3.3 to 5.8 microg x ml(-1) and from 3 to 20 microg x ml(-1) respectively. In four patients with renal impairment, the highest laudanosine concentration was > 10 microg x ml(-1). No seizure was recorded. A fixed infusion rate of atracurium in acute respiratory distress syndrome patients provided an effective muscle paralysis with a rapid neuromuscular recovery but can lead to accumulation of laudanosine in patients with renal impairment.

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.

Pharmacokinetic-pharmacodynamic modeling of atracurium in intensive care patients

The authors have studied 10 critically ill patients with acute respiratory distress syndrome who required a neuromuscular blocking drug to assist mechanical ventilation. Patients received a bolus dose of 1 mg/kg of atracurium followed by a constant infusion rate of 1 mg/kg/h of this drug for 72 hours. Neuromuscular block was monitored using an accelerograph. Blood samples were obtained over a 96-hour period. A preliminary independent analysis was done to estimate the individual pharmacokinetic parameters; data were consistent with a one-compartment model. The pharmacodynamic data analysis was then performed using the changes in train-of-four (TOF) count as an index of the therapeutic effect of atracurium. Pharmacokinetic-dynamic variables were calculated using the Sheiner model and the Hill equation. The elimination half-life of atracurium averaged 22 minutes. Mean volume of distribution and plasma clearance were 217 ml/kg and 550 ml/min, respectively. There was a significant hysteresis loop when the TOF count was plotted against predicted plasma atracurium concentrations. The mean sigmoidicity factor, gamma, was 4.04. The concentration producing 50% of the Emax was 1.36 micrograms/mL, and the mean ke0 was 0.059 min-1. Recovery time ranged from 30 to 80 minutes, and none of the patients of this study had residual paralysis.

Guidelines in pulmonary medicine: a 25-year profile

OBJECTIVE

We attempted to identify clinical practice guideline and pathway articles in the area of pulmonary medicine published in peer-reviewed journals since 1974.

DESIGN

Review.

DATA SOURCES

MEDLINE, the Cochrane Database, Best Evidence, and Abstracts of Clinical Care Guidelines from January 1974 to December 1998.

STUDY SELECTION

All articles contained relevant search terms for pulmonary topics and were included irrespective of setting (primary or specialty, inpatient or outpatient). Controlled and uncontrolled trials as well as observational studies and consensus opinion/statements were all identified. The articles were stratified by design as well as by pulmonary topic.

DATA EXTRACTION

Limited data on study type, study focus, year of publication, and results of study were abstracted.

RESULTS

Our criteria yielded 271 articles, including 115 consensus statements and expert opinion guidelines; 30 controlled studies, meta-analyses, or systematic reviews; and 126 uncontrolled trials and observational studies. Of these, 82 articles (30.3%) related to asthma, 46 articles (17.0%) related to COPD, and 36 articles (13.3%) related to pneumonia. In addition, we tracked the increasing publication of all guideline-related pulmonary articles; randomized, controlled trials (RCTs); systematic reviews; and consensus statements by year for the past 25 years.

CONCLUSION

Pulmonary guidelines are increasingly published in peer-reviewed journals, but few are tested clinically in RCTs. There is continued reliance on consensus statements and expert opinion. Pulmonary guideline publications have continued to dramatically increase in number and in importance since 1974, both on the local level and internationally.