Exercise in Critical Care

Original Editor - David Gillette

Top Contributors - Kim Jackson, Rachael Lowe, David Gillette, Karen Wilson and Samuel Adedigba  


Early mobility in the hospital setting is getting more scrutiny and study.  This page on ambulation on a ventilator is broken into four parts: Part I: Background; Part II: Case Reports; Part III: Research Studies; Part IV: Future Direction.

Part I: Background

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

Part II: Case Reports

As of  March 2009, there were four case reports found in a search of PubMed. There is one additional report that is inaccessible (in Phys Ther from 1972).
1. Burns JR, Jones FL. Early ambulation of patients requiring ventilatory assistance. Chest. 1975; 68:608.

In this letter to the editor, the authors acknowledge the problems of bedrest and the problems of ambulating a patient on a respirator, and give a brief description of their walker, and their antecdotal impression (developed over 3 years of the program) of facilitated/hastened weaning and minimizing problems of bedrest.

2. Kirshblum SC, Bach JR. Walker modification for ventilator-assisted individuals: case report. Am J Phys Med Rehabil. 1992; 71:304-306.

The purpose of this report was to give a report on ambulating a patient using 24-hr non-invasive ventilator support. The patient was a 53 y.o. male with Milroy's disease, respiratory faulure, restrictive pulmonary disease, and a history of R mid-lobe pneumonectomy and acute respiratory failure. Before being admitted he could walk <200' and climb 5 or fewer steps before experiencing dyspnea.

He was admitted and intubated, given bilateral chest tubes, treated for pneumonia, and diagnosed with pulmonary fibrosis. He was given a trach at day 52, and 4 months of attempted vent weaning failed. However he did convert from Intermittent Positive Pressure Ventilation via the trach to IPPV via mouth during the day and nose at night. At 7 months he was transferred to rehab, dependent in all ADL's and only able to take a few steps.

The facility commenced a comprehensive rehab program consisting of diaphragmatic/ glossopharyngeal breathing, biofeedback, and general strength/ mobility/ endurance. As the pt was not able to manuever a wheelchair with all the equipment required, they modified a walker to assist. He was d/c'ed home after 60 days independent in all ADL's and ambulated >400' with the walker with his O2 sats >94%, and eventually returned to work full-time. At the time of the writing he was still on IPPV for 20 hrs/day with an improved vital capacity (660ml to 1050ml).

Strengths: Presents possibility of vent-dependent individual regaining functional ability and social roles

Limitations: case study; no criteria for beginning ambulation; no specifics of rehab program or walker modifications

3. Smith T, Forrest G, Evans G, Johnson RK, Chandler N. The Albany Medical College ventilator walker. Arch Phys Med Rehabil. 1996; 77:1320-1321.

The purpose of this report was to describe the design and use of a walker that could accomodate a ventilator and O2 tank. After describing considerations and the construction of the walker, they presented a 69 y.o. female admitted for an elective CABG, complicated by a difficult vent weaning due to obesity, hemi-diaphram paralysis, CHF, left lower lung atelectasis, and obstructive air flow secondary to secretions. She received a trach one month after the surgery, and two days later started using the walker two times a day. Over the next week the PT reported significant improvement in strength and functional mobility. Five months after the initial surgery she could walk without an assistive device or supplemental O2.

Strengths: specifics for walker dimensions

Limitations: case study; no specific criteria for beginning ambulation.

4. Perme CS, Southard RE, Joyce DL, Noon GP, Loebe M. Early mobilization of LVAD recipients who require prolonged mechanical ventilation. Tex Heart Inst J. 2006; 33:130-133.

The purpose of this case report was to "report our regimen of mobilization with the aid of a prortable ventilator, in patients with cardiac cachexia and LVAD implantation. Further, we describe the specific physical therapy interventions used in an LVAD patient who required prolonged mechanical ventilation after device implantation."

The authors generally present their physical therapy evaluation which includes ventilator settings or O2 requirements, their PT interventions (positioning, strengthening and breathing exercises, bed mobility, transfers, gait, and education; with frequency 1x/day 6-7days/wk, 15 minutes - 1 hr), and criteria for termination of PT session (significant drop in LVAD flow, hypotension signs/symptoms, severe/ intolerable dyspnea, O2 level <90%, significant chest pain, extreme fatigue, and request of pt to stop).

Case report: 51 y.o. male with heart failure secondary to dilated cardiomyopathy, and a R lower lobe nodule. Over next 5 weeks pt became progressively worse in his cardiac function, developed renal insufficiency and repiratory failure which resulted in him being intubated. He was placed on an LVAD and they resected his right lower lobe, which was further complicated by medical problems requiring continued ventilation. PT was ordered on Day 7 after he failed the first weaning trial. He was given LE strengthening exercises and mobilization (sit EOB, stand, and bed<>chair), and he was progressed to gait training activities around the ICU while on a vent. In his 49 day ICU stay he was vented 48 days and received 25 daily PT sessions (17 LE exercise sessions, 22 EOB sessions, 21 standing sessions, and 18 gait training sessions, 4 of which they used a portable ventilator). The patient improved to a T-collar, ambuation without vent support, and was weaned from the vent. After 6 weeks he had a heart transplant and d/c'ed home.

Strengths: Gave more specifics of PT involvement

Limitations: case study; no specific criteria for beginning ambulation other than that they can take a few steps; unclear as to session length/ consistency or ventilation while ambulating.

Part III: Research Studies

(as of March 2009)

1. Bailey P, Thomsen GE, Spuhler VJ, Blair R, Jewkes J, Bezdjian L et al. Early activity is feasible and safe in respiratory failure patients. Crit Care Med. 2007; 35:139-145.

In this study the researchers wanted to know if early activity in critically ill patients was feasible and safe. In this prospective cohort study, the participants patients in a RICU (n=103) who had been on a vent for >4 days (only exclusion criteria was <4days). Pts had to be neurologically responsive to verbal stimulation, meet specific respiratory conditions (FIO2 <0.7, Positive end-expiratory pressure <11cm H2O), and meet circulatory criteria (absence of orthostatic hypotension and catacholamine drips). Those not meeting all 3 criteria had a trial of activity with close monitoring for adverse events. The activity plan required a PT, RT, RN, critical care technician, 2x/day. Activity events included sitting EOB, standing, ambulating. Adverse events were low and did not require extubation, increased cost, or longer stay. Avg ambulation at d/c was 212’ (69% could ambulate 100' or more); age not a factor in participation. Their conclusion was that early activity is feasible and safe in this population, and is a possible therapy to prevent or treat critical illness-related neuromuscular complications. This study did not have a control group, so they could not say that early activity improves d/c time or long-term outcomes.

2.Thomsen GE, Snow GL, Rodriguez L, Hopkins RO. Patients with repiratory failure increase ambulation after transfer to an intensive care unit where early activity is a priority. Crit Care Med. 2008; 36:1119-1124.

At the same location as the Bailey study, the researchers hypothesized that "ambulation of patients with acute respiratory failure would increase with transfer to an intensive care unit where activity is a key component of patient care." Their participants (N=104) were patients who were vented >4 days, did not have a neurological disease that prevented activity (e.g. stroke), were not readmitted to the RICU, and were not terminally ill. Those patients were also required to have been in another hospital ICU for 2 days before being transferred to this unit, and have a stay on their unit of 2 or more days so they could compare activity levels. To start the activity protocol they had to be able to follow commands, have FiO2 <0.7 and positive end-expiratory pressure <11cm H2O, no catecholemine drips and no sign of orthostatic hypotension. During ambulation (yes/no, and how far recorded each time) they would monitor O2 sats and BP. They concluded that transferring a patient who is having acute respiratory failure to their unit significantly improved ambulation, even when taking the underlying pathophysiology into account; that the ICU setting "may contribute unnecessary immobilization throughout the course of acute respiratory failure;" and that sedatives significantly reduce the possibility of ambulation. They also called for further reserach to determine if ICU immobility affects long-term neuromuscular dysfunction and if early activity in the ICU improves outcomes.

3. Morris PE, Goad A, Thompson C, Taylor K, Harry B, Passmore L et al. Early intensive care unit mobility thereapy in the treatment of acute respiratory failure. Crit Care Med. 2008; 36:2238-2243.

In this study, the researchers wanted to answer if physical therapy in the intensive care unit provides benefit (the theory is sound, but there is no data). In a medical intensive care unit, patients who were intubated within the past 48 hours and admitted to the MICU within 72 hours were enrolled. Inclusion criteria was >18 years old and having an ET tube, while exclusion criteria was inability to walk before their ICU illness (use of AD were allowed), cognitive impairment before the illness (defined as "nonverbal"), immuncompromised/on prednisone before admission, having a neuromuscular disease such as myasthenia gravis, Guillan-Barre or ALS which could impair weaning from the vent, acute stroke, BMI >45, hip fracture, unstable c-spine or a pathological fracture, being on a vent >48 hours before being transferred from another facility, >72 hours for current admittance or transferring from another hospital with >72 hour stay, a DNR order upon admission, recent hospitalization (30 days), cancer treatment in last 6 months, and re-admit to ICU during this stay.

Interestingly, "it was determined a priori that only patients who survived to a hospital discharge would be included in the outcome analyses based on results of prestudy data that found few patients who died in the ICU achieved sufficient wakefulness to be considered for [PT] before their death. Thus, outcome data were compared for patients in the Usual Care Group with patients in the Protocol group who survived to hospital discharge."

Patients were assigned to the Usual Care group (N=165) or the Protocol group (N=165) with a block design. The UCG included usual treatment (PROM), whereas the PG received four levels of treatment in the protocol (1 - PROM, 2 - PROM, active resistance, sitting, 3 - same as #2 but now sitting EOB, and 4 - same as #3 but adding active transfers and building to ambulation. This protocol was implemented 7d/wk with an RN, a CNA, and a PT. Primary outcomes were the proportion of patients receiving PT in the total number of patients surviving to discharge. Their conclusion was that early mobility was feasible, safe, did not increase costs, and reduced ICU and hospital length of stays for those receiving the protocol.

Part IV: Future Directions

We know that immobility has negative reprecussions for the patient, and that being on a ventilator has even more negative repercussions. There are studies to show that PT and ambulation of patients on a ventilator is feasible and safe. So where do we go from here?

Address barriers to mobility

A few to consider from Morris and Stiller references:

  • Safety concerns
    - dislodging lines or tubes
    - reducing already low oxygenation and hemodynamic parameters (NOTE: the Stiller references and Gosselink reference contain a good flowchart to start with)
  • Sedation (which reduces mentation)
  • Cost
    - number of workers needed
    - mobility aids needed (do we need to build our own?)
  • Obesity
  • Time

Changing a culture

Given the cost to the patient being immobilized and on a vent, are addressing the barriers a benefit? Even if it is, it will likely require a culture change - on the unit and in the hospital. So how to do that? Those who have gone before (Hopkins et al) have laid out a path that they believe will help with this culture change:

Stage 1 - establish a sense of urgency
-look at pt at d/c; understand limitations they have and are faced with

Stage 2 - create a powerful guiding coalition
-nurse manager, physician director, and a few influential people who are committed to change

Stage 3 - create a vision
-for your job, what can you do as part of the process of care?

Stage 4 - communicate the vision
-get the idea to other ICU’s about the importance of early ambulation

Stage 5 - empower others to act
-being able to share small parts of your job – d/c a line or flush a tube – learn how to work with each other and what each other does

Stage 6 - plan and create short-term wins
-e.g. as # of admissions increased to RICU, the FTE increased

Stage 7 - consolidating improvements, making more change
-reporting adherence rates to desired action

Stage 8 - institutionalize new approaches
-within the team ("this is how it is done") and outside (respect for and desire to follow the new approach)


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