ICU Acquired Weakness

Introduction[edit | edit source]

Intensive Care Unit

Intensive care unit-acquired weakness (ICU-AW), is a skeletal muscle disorder that commonly occurs following sepsis, mobility restriction, hyperglycemia, and glucocorticoids or neuromuscular blocking agents use [1]. The three subsets of ICUAW are Critical Illness Neuromyopathy (CINM), Critical Illness Polyneuropathy (CIP) and Critical Illness Myopathy (CIM)).[2][3] This muscle weakness evolves as a secondary disorder while patients are in the ICU with life-threatening conditions. [4]

ICUAW's causes

  • Generalized muscle weakness, effecting respiratory muscles more often than the limb muscles.[4]
  • Delayed mobilization
  • Prolongated hospitalization.[3][5]

Knowledge of ICUAW among clinicians, such as physiotherapists, enhances effective delivery of healthcare to ICU patients. This page examines the literature on ICUAW including its management and physiotherapy role in ICUAW. See also Physiotherapists Role in ICU

In this 4 minute video we explain what ICUAW is and how important it is that early rehabilitation is started.

[6]

Overview of ICU acquired weakness

Risk Factors[edit | edit source]

Modifiable risk factors
  • Long critical illness
  • Neuromuscular junction blockers
  • High dose corticosteroids
  • High dose anti hypotensive drugs
  • Immobility, prolonged bed rest
  • Hyperglycaemia
  • Use of aminoglycosides
Non-modificable risk factors
  • Female
  • Initial low muscle mass
  • Malnutrition prior to admission
  • Severe sepsis
  • Multiorgan system failure
  • Severe illness

[7]

Clinical Presentation[edit | edit source]

Common clinical presentation of ICUAW is

  • Presents about 1 week into the critical illness
  • Sensation is (generally) preserved, but peripheral sensation can eventually be lost
  • A generalized, usually symmetrical, limb weakness, with proximal muscles more affected than the distal muscles.
  • Cranial nerve function and autonomic nervous system function usually preserved[7]
  • Reduction of tendon reflexes,
  • Facial grimacing to painful stimulation without withdrawal of limbs is another clinical presentation.
  • May have autonomic dysfunction[5]

Diagnostic Procedures[edit | edit source]

Diagnosis of ICUAW may involve: [5]

  • Medical Research Council (MRC) sum score for muscle strength evaluation. The MRC sum score ranges between 0 and 60, and a score of <48 is suggesting ICUAW.
  • Electrophysiological like EMG, Nerve Conduction (NC) test to evaluates neuromuscular integrity
  • Handheld dynamometry and handgrip strength for evaluating some neuromuscular function
  • Maximal inspiratory pressure to assess inspiratory muscle strength,

Outcome Measures[edit | edit source]

  1. Muscle strength (MRC) and Neuromuscular integrity evaluation (electrophysiological testing-EMG, NC)
  2. Respiratory Muscles assessment (Incentive spirometer)
  3. Functional Independence Measure (FIM)

An exploratory study investigating functional outcomes at hospital discharge and health-related quality of life after six months in critically ill patients with severe, moderate, or no ICUAW suggested that the participants without ICUAW had superior functional performance at hospital discharge and shorter length of hospital stays when compared to participants with ICUAW. The primary functional outcomes for this analysis were the Functional Independence Measure (FIM) and the 6-Minute Walk Test (6MWT) at hospital discharge. Additional secondary outcomes of interest were FIM at ICU discharge, Timed ‘Up & Go’ at hospital discharge, hospital length of stay and discharge destination, tracheostomy incidence, ICU readmissions, hospital, and 6-month mortality as well as participants’ health-related quality of life determined with the Short Form 36 (SF-36) six months after hospital discharge[8].

Physiotherapy Role in ICUAW[edit | edit source]

  1. Respiratory Muscle Training: Respiratory muscle weakness is a common feature of ICUAW patients. One explanation for this is that the critically ill patient depends on the mechanical ventilator for a longer period of time, which makes the respiratory muscles weak. Inspiratory muscle training when the patient is on a mechanical ventilator and when weaned improves the strength of the respiratory muscle[9]. Inspiratory muscle training can be achieved by [10]: Spontaneous breathing by means of a nonlinear resistor that increases respiratory workload; Insensitive trigger threshold can be used during assisted mechanical ventilation support; A threshold device (a device that provides a known constant inspiration resistance through the use of a flow-independent one-way valve) can also be used.
  2. Physical Training: Involves joint mobilization and muscle training regimes that aim to increase muscle strength, minimize atrophy, improve muscle mass, and function. It can be divided into the ICU admission period when the patient is on a ventilator and post ICU rehabilitation when the patient is weaned. A review by Nobuto Nakanishi et al. shows there exists progressive muscle atrophy in critically ill patients, and physical therapy, electrical muscle stimulation, muscle protective ventilator settings, and glucose control can help prevent atrophy and preserve muscle mass[11]. A systematic review and meta-analysis suggest early rehabilitation in the ICU reduces the incidence of developing ICUAW[12].
    • Physical training for patients with ICUAW during admission includes: Passive range of motion treatment sessions Passive cycling Electrical muscle stimulation (EMS)

The EMS can also be used in preventing ICUAW.[9]

Post ICU

Post-ICU Physical therapy rehabilitation of a patient with ICUAW is not limited to the following[9]:

  • Strength training program
  • Aerobic session such as walking, arm and leg cycling exercises,
  • Functional activities therapy regime
  • And the provision of self-help manuals and program

Prevention[edit | edit source]

ICUAW is a recurring complication of critical illness, with negative short- and long-term consequences and should be avoided if possible[4]. A recent Cochrane review outlines some preventative measures:

  • Strict glucose control
  • Early mobility rehabilitation
  • Electrical muscle stimulation (EMS) may have a preventative role, but this technique requires further study.

Good sense suggests these measures:

  • Adequate nutrition
  • Electrolyte replacement
  • Minimal use of steroids, sedation and NMJ blockade
  • Physiotherapy with limb mobilisation while still critically ill
  • Effort to wean ventilation[7]

References[edit | edit source]

  1. Wenkang Wang et al Intensive Care Unit-Acquired Weakness: A Review of Recent Progress With a Look Toward the Future Available: https://www.frontiersin.org/articles/10.3389/fmed.2020.559789/full (accessed 29.12.2022)
  2. Vanhorebeek I, Latronico N, Van den Berghe G. ICU-acquired weakness. Intensive Care Medicine. 2020 Feb 19:1-7.
  3. 3.0 3.1 Judemann K, Lunz D, Zausig YA, Graf BM, Zink W. Intensive care unit-acquired weakness in the critically ill: critical illness polyneuropathy and critical illness myopathy. Der Anaesthesist. 2011 Oct;60(10):887-901.
  4. 4.0 4.1 4.2 Vanhorebeek I, Latronico N, Van den Berghe G. ICU-acquired weakness. Intensive care medicine. 2020 Apr;46(4):637-53.Available:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7224132/ (accessed 25.12.2022)
  5. 5.0 5.1 5.2 Hermans G, Van den Berghe G. Clinical review: intensive care unit acquired weakness. Critical care. 2015 Dec;19(1):274.
  6. IC Connect ICU acquired weakness Available from https://www.youtube.com/watch?v=8cbw14lWLkY&feature=emb_logo
  7. 7.0 7.1 7.2 Deranged Physiology ICU-acquired weakness Available:https://derangedphysiology.com/main/required-reading/neurology-and-neurosurgery/Chapter%20209/icu-acquired-weakness (accessed 25.12.2022)
  8. Eggmann S, Luder G, Verra ML, Irincheeva I, Bastiaenen CH, Jakob SM. Functional ability and quality of life in critical illness survivors with intensive care unit acquired weakness: A secondary analysis of a randomised controlled trial. PloS one. 2020 Mar 4;15(3):e0229725.
  9. 9.0 9.1 9.2 Hodgson CL, Tipping CJ. Physiotherapy management of intensive care unit-acquired weakness. Journal of physiotherapy. 2017 Jan 1;63(1):4-10.
  10. Anderlini A, de Andrade FM, Figueiroa JN, Lemos A, Bezerra AL. Inspiratory muscle training and physical training for reducing neuromuscular dysfunction in critically ill adults in intensive care units. The Cochrane database of systematic reviews. 2017 May;2017(5).
  11. Nakanishi N, Takashima T, Oto J. Muscle atrophy in critically ill patients: a review of its cause, evaluation, and prevention. The Journal of Medical Investigation. 2020;67(1.2):1-0.
  12. Anekwe DE, Biswas S, Bussières A, Spahija J. Early Rehabilitation Reduces the Likelihood of Developing Intensive Care Unit-Acquired Weakness: A Systematic Review and Meta-Analysis. Physiotherapy. 2019 Dec 19.