Neuromuscular Blockade

Pharmacodynamics

• decreased ventilator dyssynchrony
• improved lung compliance
• decreased metabolic demand

Recommendations (2016 Clinical Practice Guidelines)

Short-Term Indications

1. Indicated for facilitation of intubation

Long-Term Indications and Contraindications

1. Use NMB in severe ARDS with PF ratio < 150 (ACURASYS/ROSE trials)
2. Do not routinely use NMB in status asthmaticus
3. Trial NMB in those with life-threatening profound hypoxemia, respiratory acidosis, hemodynamic compromise.
4. Consider NMB for overt shivering in therapeutic hypothermia.
5. Reduce dose in myasthenia gravis patients.

Adjunct Care

1. Analgesia and sedation should be used prior to and during NMB.
2. NMB patients should get structured physiotherapy.
3. Scheduled eye care
4. Maintain a blood glucose less than 10 mM

Dosing and Withdrawal

1. Use ideal body weight or adjusted body weight if the patient is obese
2. Withdraw NMB at the end of life
3. Use TOF in combination with overall clinical assessment

Specific NMBAs

Benzylisoquinolinium Agents

Atracurium Cisatracurium Mivacurium

Aminosteroidal Agents

Rocuronium Vecuronium Pancuronium

Reversal Agents

Less commonly used; current critical care trends allow for spontaneous recovery most of the time and pharmacologic reversal is uncommon.

Acetylcholinesterase Inhibitors

Neostigmine and edrophonium and pyridostigmine antagonize the action of NMBAs by inhibiting acetylcholinesterase, increasing the junctional concentration of acetylcholine. Median reversal time is approx. 15 minutes. These only really work if there is sufficiently low NMBA anyways (TOF > 3). Increases muscarinic activity, so give in conjunction with glycopyrrolate or another antimuscarinic to avoid significant bradycardia and bronchoconstriction.

Sugammadex

This is an encapsulating gamma-cyclodextrin compound that binds rocuronium and vecuronium. Compound is renally excreted. Binding happens in the plasma. Can uniquely reverse deep and profound levels of NMB and is faster than spontaneous recovery from succinylcholine.

Complications of Neuromuscular Blockade

• due to immobility and paralysis:
  • ICU-acquired weakness (ICUAW): critical illness polyneuropathy (CIP), critical illness myopathy, (CIM), and critical illness neuromyopathy (CINM)
  • DVT risk is highly increased as well
  • pressure ulcers, nerve injuries
  • unintended awareness and recall
• on extubation
  • hypoxemia
  • need for reintubation
  • increased rsk of pneumonia and upper airway obstruction
  • post-extubation stridor

References

1. Murray MJ, DeBlock H, Erstad B, et al. Clinical Practice Guidelines for Sustained Neuromuscular Blockade in the Adult Critically Ill Patient. Critical Care Medicine. 2016;44(11):2079-2103. doi:10.1097/CCM.0000000000002027
2. Renew JR, Ratzlaff R, Hernandez-Torres V, Brull SJ, Prielipp RC. Neuromuscular blockade management in the critically Ill patient. Journal of Intensive Care. 2020;8(1):37. doi:10.1186/s40560-020-00455-2