Management of Neuromuscular Blocking Agents in Critically Ill Patients with Lung Diseases

The use of neuromuscular blocking agents (NMBAs) is common in the intensive care unit (ICU). NMBAs have been used in critically ill patients with lung diseases to optimize mechanical ventilation, prevent spontaneous respiratory efforts, reduce the work of breathing and oxygen consumption, and avoid patient-ventilator asynchrony. In patients with acute respiratory distress syndrome (ARDS), NMBAs reduce the risk of barotrauma and improve oxygenation. Nevertheless, current guidelines and evidence are contrasting regarding the routine use of NMBAs. In status asthmaticus and acute exacerbation of chronic obstructive pulmonary disease, NMBAs are used in specific conditions to ameliorate patient-ventilator synchronism and oxygenation, although their routine use is controversial. Indeed, the use of NMBAs has decreased over the last decade due to potential adverse effects, such as immobilization, venous thrombosis, patient awareness during paralysis, development of critical illness myopathy, autonomic interactions, ICU-acquired weakness, and residual paralysis after cessation of NMBAs use. The aim of this review is to highlight current knowledge and synthesize the evidence for the effects of NMBAs for critically ill patients with lung diseases, focusing on patient-ventilator asynchrony, ARDS, status asthmaticus, and chronic obstructive pulmonary disease.

Current Practice Review in the Management of Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) presents as an acute inflammatory lung injury characterized by refractory hypoxemia and non-cardiac pulmonary edema. An estimated 10% of patients in the intensive care unit and 25% of those who are mechanically ventilated are diagnosed with ARDS. Increased awareness is warranted as mortality rates remain high and delays in diagnosing ARDS are common. The COVID-19 pandemic highlights the importance of understanding ARDS management. Treatment of ARDS can be challenging due to the complexity of the disease state and conflicting existing evidence. Therefore, it is imperative that pharmacists understand both pharmacologic and non-pharmacologic treatment strategies to optimize patient care. This narrative review provides a critical evaluation of current literature describing management practices for ARDS. A review of treatment modalities and supportive care strategies will be presented.

Critical Care Pharmacist Attitudes and Perceptions of Neuromuscular Blocker Infusions in ARDS

BACKGROUND

Current critical care pharmacist (CCP) practices and perceptions related to neuromuscular infusion (NMBI) use for acute respiratory distress syndrome (ARDS) maybe different with the COVID-19 pandemic and the publication of 2020 NMBI practice guidelines.

OBJECTIVE

To evaluate CCP practices and perceptions regarding NMBI use for patients with moderate-severe ARDS.

METHODS

We developed, tested, and electronically administered a questionnaire (7 parent-, 42 sub-questions) to 409 American College of Clinical Pharmacy (ACCP) Critical Care Practice and Research Network members in 12 geographically diverse states. The questionnaire focused on adults with moderate-severe ARDS (PaO2:FiO2<150) whose causes of dyssynchrony were addressed. Two reminders were sent at 10-day intervals.

RESULTS

Respondents [131/409 (32%)] primarily worked in a medical intensive care unit (ICU) 102 (78%). Compared to COVID-negative(-) ARDS patients, COVID positive(+) ARDS patients were twice as likely to receive a NMBI (34 ± 18 vs.16 ± 17%; P < 0.01). Respondents somewhat/strongly agreed a NMBI should be reserved until after trials of deep sedation (112, 86%) or proning (92, 81%) and that NMBI reduced barotrauma (88, 67%), dyssynchrony (87, 66%), and plateau pressure (79, 60%). Few respondents somewhat/strongly agreed that a NMBI should be initiated at ARDS onset (23, 18%) or that NMBI reduced 90-day mortality (12, 10%). Only 2/14 potential NMBI risks [paralysis awareness (101, 82%) and prolonged muscle weakness (84, 68%)] were frequently reported to be of high/very high concern. Multiple NMBI titration targets were assessed as very/extremely important including arterial pH (109, 88%), dyssynchrony (107, 86%), and PaO2: FiO2 ratio (82, 66%). Train-of-four (55, 44%) and BIS monitoring (36, 29%) were deemed less important. Preferred NMBI discontinuation criteria included absence of dysschrony (84, 69%) and use ≥48 hour (72, 59%).

CONCLUSIONS AND RELEVANCE

Current critical care pharmacists believe NMBI for ARDS patients are best reserved until after trials of deep sedation or proning; unique considerations exist in COVID+ patients. Our results should be considered when ICU NMBI protocols are being developed and bedside decisions regarding NMBI use in ARDS are being formulated.

Atracurium Versus Cisatracurium in the Treatment of Acute Respiratory Distress Syndrome

Background: Neuromuscular blocking agents are one of the few medication classes that have demonstrated a clinical benefit in patients with severe acute respiratory distress syndrome (ARDS). However, most literature utilized cisatracurium, and utilization of atracurium is limited to 1 small study. Objective: The purpose of this study was to provide further evidence comparing the safety and efficacy of atracurium versus cisatracurium for the treatment of ARDS. Methods: This multicenter, retrospective, observational cohort noninferiority study was conducted at 3 hospitals within a tertiary health care system. We included subjects diagnosed with ARDS who received either atracurium or cisatracurium for at least 12 hours. The primary outcome measured the change in PaO2/FiO2 (P/F) ratio from baseline to 48 hours after initiation. Results: Baseline characteristics were similar between groups except for a higher median age and a higher proportion of subjects who were COVID-positive in the atracurium group. There were also some noted differences in the baseline P/F ratios. In a multivariable model adjusting for baseline characteristics, the change in the P/F ratio for atracurium was noninferior to cisatracurium at 24, 48, and 72 hours. A significant cost reduction, measured as cost per patient per day, was seen with the use of atracurium ($14.81-$25.16 vs $33.86-$41.91). Conclusion: Atracurium appears to be a safe and cheaper alternative agent in the management of ARDS.

Personalized medicine targeting different ARDS phenotypes: The future of pharmacotherapy for ARDS?

INTRODUCTION

Acute respiratory distress syndrome (ARDS) still represents a major challenge with high mortality rates and altered quality of life. Many well-designed studies have failed to improve ARDS outcomes. Heterogeneity of etiologies, mechanisms of lung damage, different lung mechanics, and different treatment approaches may explain these failures. At the era of personalized medicine, ARDS phenotyping is not only a field of research, but a bedside consideration when implementing therapy. ARDS has moved from being a simple syndrome to a more complex area of subgrouping. Intensivists must understand these phenotypes and therapies associated with a better outcome.

AREAS COVERED

After a brief sum-up of the different type of ARDS phenotypes, we will present some relevant therapy that may be impacted by phenotyping. A focus on pharmacotherapy will be realized before a section on non-pharmaceutical strategies. Eventually, we will highlight the limits of our knowledge of phenotyping and the pitfalls of personalized medicine.

EXPERT OPINION

Biological and morphological ARDS phenotypes are now well studied. The future of ARDS therapy will go through phenotyping that allows a personalized medication for each patient. However, a better assessment of these phenotypes is required, and clinical trials should be conducted with an ad-hoc phenotyping before randomization.

Neuromuscular blocking agents in the intensive care unit

Neuromuscular blocking agents (NMBA) are a controversial therapeutic option in the approach to the critically ill patient. They are not innocuous, and the available evidence does not support their routine use in the intensive care unit. If necessary, monitoring protocols should be established to avoid residual relaxation, adverse effects, and associated complications. This narrative review discusses the current indications for the use of NMBA and the different tools for monitoring blockade in the intensive care unit. However, expanding the use of NMBA in critical settings merits the development of prospective studies.

Biphasic positive airway pressure spontaneous breathing attenuates lung injury in an animal model of severe acute respiratory distress syndrome

OBJECTIVE

To compare the effects of unassisted spontaneous breathing (SB) and complete muscle paralysis (PC) on early severe acute respiratory distress syndrome (ARDS) in an animal model, and to explore the possibility of biphasic positive airway pressure (BIPAP) as lung protective ventilation support for patients in the early stage of severe ARDS.

METHODS

Twelve healthy beagle dogs between the ages of 10 and 15 months were randomly divided into two groups: the SB group (BIPAP_SB) and the PC group (BIPAP_PC). Arterial blood samples were drawn before modelling. Arterial blood gas analysis and mechanical tests were conducted. The animal model of severe ARDS was established using a deep intravenous injection of oleic acid, and BIPAP ventilation was performed for 8 hours. Lung tissue and blood were taken to detect lung function, inflammatory reactions and degree of pathological damage.

RESULTS

At the beginning of the experiment, there was no significant difference in the arterial blood gas analysis between the two groups (p > 0.05). After successful modelling, the oxygenation index and the end-expiratory lung volume in the SB group were significantly higher than those in the PC group 8 hours after MV. Pathologically, the wet-dry ratio and pathological score of the PC group were higher than those of the SB group; the lung injury in the gravity-dependent area in the SB group was less than that in the PC group (p< 0.05).

CONCLUSIONS

In the early stage of severe ARDS induced by oleic acid, compared with PC, retention of the BIPAP mode of SB can reduce the risk of lung injury and improve respiratory function.

Muscle dysfunction in the long coronavirus disease 2019 syndrome: Pathogenesis and clinical approach

In long coronavirus disease 2019 (long COVID‐19), involvement of the musculoskeletal system is characterised by the persistence or appearance of symptoms such as fatigue, muscle weakness, myalgia, and decline in physical and functional performance, even at 4 weeks after the onset of acute symptoms of COVID‐19. Muscle injury biomarkers are altered during the acute phase of the disease. The cellular damage and hyperinflammatory state induced by severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection may contribute to the persistence of symptoms, hypoxaemia, mitochondrial damage, and dysregulation of the renin‐angiotensin system. In addition, the occurrence of cerebrovascular diseases, involvement of the peripheral nervous system, and harmful effects of hospitalisation, such as the use of drugs, immobility, and weakness acquired in the intensive care unit, all aggravate muscle damage. Here, we review the multifactorial mechanisms of muscle tissue injury, aggravating conditions, and associated sequelae in long COVID‐19.

Cisatracurium Continuous Infusion Versus No Neuromuscular Blockade for Acute Respiratory Distress Syndrome on Venovenous Extracorporeal Membrane Oxygenation

The benefit of continuous infusion neuromuscular blockade concurrently with venovenous (VV) extracorporeal membrane oxygenation (ECMO) in patients with acute respiratory distress syndrome who are receiving mechanical ventilation remains unclear. Adult patients with severe acute respiratory distress syndrome requiring VV ECMO were analyzed in 2 groups: continuous infusion neuromuscular blockade with cisatracurium vs no neuromuscular blockade. Similar mechanical ventilation strategies were used. The primary end point was duration of VV ECMO. This single-center, retrospective observational cohort included a total of 47 patients, 28 of whom received continuous infusion cisatracurium and 19 patients who did not receive neuromuscular blockade. There was no difference in the duration of VV ECMO in patients who received cisatracurium, 226.5 hours (interquartile range, 119-362.3) vs 187.0 hours (interquartile range, 108-374) in the group who did not receive a paralytic (P = .64). There were no differences in secondary outcomes of days in the hospital, days free of organ dysfunction, ECMO survival, or discharged alive. Among patients with severe ARDS who were managed with VV ECMO, patients who received continuous infusion cisatracurium had no difference in the duration of VV ECMO compared to the nonparalytic comparator group.

Comparison of fixed dose versus train-of-four titration of cisatracurium in acute respiratory distress syndrome

PURPOSE

To compare the ventilatory and clinical outcomes associated with a fixed-dose cisatracurium infusion versus a titrated infusion strategy in patients with Acute Respiratory Distress Syndrome (ARDS).

MATERIALS AND METHODS

Single-center, retrospective, cohort study in a medical ICU of a tertiary care academic medical center. Adult patients ≥18 years old with a continuous infusion of cisatracurium for ≥12 h for treatment of ARDS were included. The primary outcome was the PaO2 /FiO2 ratio assessed at 24 and 48 h following cisatracurium initiation. Secondary outcomes included amount of average dose of drug administered, 28-day ventilator-free days, LOS, and hospital mortality.

RESULTS

167 patients were included; median baseline PaO2/FiO2 was 97 (76-146), median SOFA score of 9 (7-11), and ICU mortality was 71/167 (43%). In a mixed-effects model, fixed dose and titrated cisatracurium associated with similar changes in PaO2/FiO2 assessed at 24 and 48 h (p = 0.316). Fixed-dose was associated with a >3-fold increase in drug exposure (average dose 6.4 (5.4-8.0) vs. 2.0 (1.5-2.8) mcg/kg/min; p < 0.001, respectively). No differences were observed in secondary clinical endpoints.

CONCLUSION

Fixed-dose cisatracurium was associated with similar ventilatory and clinical outcomes compared to titrated strategy, yet it was associated with a 3-fold increase in dose administered.