Ambulation on a vent – Part I

Acute Care

Early mobility in the hospital setting is getting more scrutiny and study – there are several recent articles in the NYT as well including one here. My CI suggested that I look at the literature on it and do an inservice on ambulation on ventilators, which they would like to start doing.  This is Part I of III – I will post the rest in the next week, and also give my view of PT, acute care, and being a student in acute care (Photo credit – Acute Care, originally uploaded by HelloMokona).

Result of inactivity/ bedrest

  • 4 hrs of bed rest: muscles deteriorate
  • 8 hrs: contractures start
  • 48 hrs: reduced perfusion, increased hemodynamic instability, increased risk for ischemia and injury
  • 1 week: 10% loss of strength in HEALTHY volunteers
  • Muscles – sarcomeres shorten, reducing contracting force and strength; slow fibers convert to fast
  • Inflammatory diseases – can cause diaphragmatic contractile dysfunction
  • Unloading/ resting diaphragm = decreased endurance
  • Sensory deprivation – anxiety, depression, disturbed sleep (therefore medicated)
  • Sense of fatigue – leads to self-limitation

Critical Illness Neuromyopathy

  • Develops during ICU (vs GB or myasthenia gravis)
  • Cardinal locomotor sign – proximal weakness, grossly symmetrical
  • Scored by a MMT sum of arm abd, elbow flex, wrist ext, hip flex, knee ext, DF, with 0 = no visible contraction, 1 = visible but no movement, 2 = active but not AG, 3 = active, AG, 4 = active, AG and resistance (NOTE: doesn’t say how much resistance!), 5 = normal power
  • <48 – significant weakness; may have sensory, DTR, muscle mass loss
  • Can be diagnosed with EMG which shows reduced action potential, and spontaneous activity occurring, but noted to not always be feasible
  • Pts with CINM – increased days on vent, longer weaning, immobility

Outcomes of prolonged ventilation

  • DVT’s, pneumonia
  • Residual weakness (12 months after admission, still have significant residual weakness – 66% of NV in 6 min walk test)
  • Sensory deficits (Study: vented >28 days: 59% with motor or sensory deficits, 95% with EMG evidence of chronic partial denervation)
  • Increased mortality (Study: PMV 98-00 – 1yr mortality 58%, 22% died in hospital, 36% died within 1 yr of d/c, 57% of survivors got off the vent)
  • Discharge location (Study: d/c disposition: 17% home, 35% to rehab, 23% to SNF.  Study: >96hrs on vent 45% to SNF, median time to home 7 months 53% had 1 or more re-admits within 12 months
  • Cognitive deficits (Reports of 27% d/c with cognitive deficits)49% of survivors return to work at 1 yr


—  Winkelman C.  Inactivity and inflammation in the critically ill patient.  Crit Care Clin. 2007; 23:21-34.

—  De Jonghe B, Lacherade J, Durand M, Sharshar T.  Critical illness nueromuscular syndromes.  Crit Care Clin.  2007; 23:55-69.

—  Carson SS.  Outcomes of prolonged mechanical ventilation.  Curr Opin Crit Care. 2006; 12:405-411.

—  Fletcher SN, Kennedy DD, Ghosh IR, et al.  Persistent neuromuscular and neurophysiologic abnormalities in long-term survivors of prolonged critical illness.  Crit Care Med 2003; 31:1012-1016.

—  Engoren M, Arslanian-Engoren C, Fenn-Buderer N.  Hospital and long-term outcome after tracheostomy for respiratory failure.  Chest 2004.  125:220-227

—  Cox CE, Carson SS, Holmes GM, Howard A, Carey TS.  Increase in tracheostomy for prolonged mechanical ventilation in North Carolina, 1993-2002.  Crit Care Med 2004; 32:2219-2226.

—  Douglass SL, Daly BJ, Gordon N, Brennan PF.  Survival and quality of life: short-term versus long-term ventilator patients.  Crit Care Med 2002; 30:2655-2662.

—  Nelson JE, Meier DE, Litka A, et al.  The symptom burden of chronic critical illness.  Crit Care Med 2004; 32:1527-1534.

—  Herridge MS, Cheung AM, Tansey CM, et al.  One year outcomes in survivors of the acute respiratory distress syndrome.  N Engl J Med 2003; 348:683-693.

—  Dowdy DW, Eid MP, Dennson CR, et al.  Quality of life after acute respiratory distress syndrome: a meta-analysis.  Intensive Care Med 2006; 32:1115-1124.

—  Davydow DS, Gifford JM, Desai SV, Bienvenu OJ, Needham DM.  Depression in general intensive care unit survivors: a systematic review.  Intensive Care Med Published online.


3 responses to “Ambulation on a vent – Part I

  1. Hi, this is great work! I was wondering if you might be interested in adding your work/allowing your work to be added to Physiopedia? We would love to have this kind of evidence-based article added to our cardiorespiratory section. Rachael

  2. That’d be great and a very welcome addition to Physiopedia, Thanks!

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