Rehabilitation in the Intensive Care Unit

ABSTRACT

Critical illness has many devastating sequelae, including profound neuromuscular weakness and psychological and cognitive disturbances that frequently result in long-term functional impairments. Early rehabilitation begun in the intensive care unit (ICU) is emerging as an important strategy both to prevent and to treat ICU-acquired weakness, in an effort to facilitate and improve long-term recovery. Rehabilitation may begin with range of motion and bed mobility exercise, then may progress when the patient is fully alert and able to participate actively to include sitting and posture-based exercise, bed to chair transfers, strength and endurance exercises, and ambulation. Electrical muscle stimulation and inspiratory muscle training are additional techniques that may be employed. Studies conducted to date suggest that such ICU-based rehabilitation is feasible, safe, and effective for carefully selected patients. Further research is needed to identify the optimal patient candidates and procedures and for providing rehabilitation in the ICU.

KEYWORDS

Rehabilitation - critical illness - muscle - exercise - mobility

REFERENCES

• 1 Nici L, Donner C, Wouters E ATS/ERS Pulmonary Rehabilitation Writing Committee et al. American Thoracic Society/European Respiratory Society statement on pulmonary rehabilitation.  Am J Respir Crit Care Med. 2006;  173 1390-1413
• 2 Ries A L, Bauldoff G S, Carlin B W et al.. Pulmonary rehabilitation: Joint ACCP/AACVPR evidence-based clinical practice guidelines.  Chest. 2007;  131(5, Suppl) 4S-42S
• 3 Global Initiative for Chronic Obstructive Pulmonary Disease .Global strategy for the diagnosis, management and prevention of chronic obstructive pulmonary disease. http://Available at: www.goldcopd.com
• 4 Bourbeau J, Julien M, Maltais F Chronic Obstructive Pulmonary Disease Axis of the Respiratory Network Fonds de la Recherche en Santé du Québec et al. Reduction of hospital utilization in patients with chronic obstructive pulmonary disease: a disease-specific self-management intervention.  Arch Intern Med. 2003;  163 585-591
• 5 Man W DC, Polkey M I, Donaldson N, Gray B J, Moxham J. Community pulmonary rehabilitation after hospitalisation for acute exacerbations of chronic obstructive pulmonary disease: randomised controlled study.  BMJ. 2004;  329 1209-1213
• 6 Garcia-Aymerich J, Lange P, Benet M, Schnohr P, Antó J M. Regular physical activity reduces hospital admission and mortality in chronic obstructive pulmonary disease: a population based cohort study.  Thorax. 2006;  61 772-778
• 7 Pitta F, Troosters T, Probst V S, Spruit M A, Decramer M, Gosselink R. Physical activity and hospitalization for exacerbation of COPD.  Chest. 2006;  129 536-544
• 8 Puhan M A, Scharplatz M, Troosters T, Steurer J. Respiratory rehabilitation after acute exacerbation of COPD may reduce risk for readmission and mortality: a systematic review.  Respir Res. 2005;  6 54-65
• 9 Morris P E. Moving our critically ill patients: mobility barriers and benefits.  Crit Care Clin. 2007;  23 1-20
• 10 Schweickert W D, Hall J. ICU-acquired weakness.  Chest. 2007;  131 1541-1549
• 11 De Jonghe B, Sharshar T, Lefaucheur J P Groupe de Réflexion et d’Etude des Neuromyopathies en Réanimation et al. Paresis acquired in the intensive care unit: a prospective multicenter study.  JAMA. 2002;  288 2859-2867
• 12 Visser L H. Critical illness polyneuropathy and myopathy: clinical features, risk factors and prognosis.  Eur J Neurol. 2006;  13 1203-1212
• 13 Young G B, Hammond R R. A stronger approach to weakness in the intensive care unit.  Crit Care. 2004;  8 416-418
• 14 Witt N J, Zochodne D W, Bolton C F et al.. Peripheral nerve function in sepsis and multiple organ failure.  Chest. 1991;  99 176-184
• 15 Berek K, Margreiter J, Willeit J, Berek A, Schmutzhard E, Mutz N J. Polyneuropathies in critically ill patients: a prospective evaluation.  Intensive Care Med. 1996;  22 849-855
• 16 Johnson K L. Neuromuscular complications in the intensive care unit: critical illness polyneuromyopathy.  AACN Adv Crit Care. 2007;  18 167-180, quiz 181–182
• 17 Dhand U K. Clinical approach to the weak patient in the intensive care unit.  Respir Care. 2006;  51 1024-1040, discussion 1040–1041
• 18 Lacomis D. Neuromuscular weakness related to critical illness. http://Available at: www.uptodate.com
• 19 Green D M. Weakness in the ICU: Guillain-Barré syndrome, myasthenia gravis, and critical illness polyneuropathy/myopathy.  Neurologist. 2005;  11 338-347
• 20 Griffiths R D, Jones C. Seven lessons from 20 years of follow-up of intensive care unit survivors.  Curr Opin Crit Care. 2007;  13 508-513
• 21 Needham D M. Mobilizing patients in the intensive care unit: improving neuromuscular weakness and physical function.  JAMA. 2008;  300 1685-1690
• 22 De Jonghe B, Lacherade J-C, Durand M C, Sharshar T. Critical illness neuromuscular syndromes.  Neurol Clin. 2008;  26 507-520, ix
• 23 Winkelman C. Inactivity and inflammation in the critically ill patient.  Crit Care Clin. 2007;  23 21-34
• 24 Topp R, Ditmyer M, King K, Doherty K, Hornyak III J. The effect of bed rest and potential of prehabilitation on patients in the intensive care unit.  AACN Clin Issues. 2002;  13 263-276
• 25 Convertino V A. Cardiovascular consequences of bed rest: effect on maximal oxygen uptake.  Med Sci Sports Exerc. 1997;  29 191-196
• 26 Timmerman R A. A mobility protocol for critically ill adults.  Dimens Crit Care Nurs. 2007;  26 175-179, quiz 180–181
• 27 Sassoon C S, Caiozzo V J, Manka A, Sieck G C. Altered diaphragm contractile properties with controlled mechanical ventilation.  J Appl Physiol. 2002;  92 2585-2595
• 28 Jubran A. Critical illness and mechanical ventilation: effects on the diaphragm.  Respir Care. 2006;  51 1054-1061, discussion 1062–1064
• 29 Watling S M, Dasta J F. Prolonged paralysis in intensive care unit patients after the use of neuromuscular blocking agents: a review of the literature.  Crit Care Med. 1994;  22 884-893
• 30 Behbehani N A, Al-Mane F, D’yachkova Y, Paré P, FitzGerald J M. Myopathy following mechanical ventilation for acute severe asthma: the role of muscle relaxants and corticosteroids.  Chest. 1999;  115 1627-1631
• 31 Campellone J V, Lacomis D, Kramer D J, Van Cott A C, Giuliani M J. Acute myopathy after liver transplantation.  Neurology. 1998;  50 46-53
• 32 Lacomis D, Giuliani M J, Van Cott A, Kramer D J. Acute myopathy of intensive care: clinical, electromyographic, and pathological aspects.  Ann Neurol. 1996;  40 645-654
• 33 Deconinck N, Van Parijs V, Beckers-Bleukx G, Van den Bergh P. Critical illness myopathy unrelated to corticosteroids or neuromuscular blocking agents.  Neuromuscul Disord. 1998;  8 186-192
• 34 Showalter C J, Engel A G. Acute quadriplegic myopathy: analysis of myosin isoforms and evidence for calpain-mediated proteolysis.  Muscle Nerve. 1997;  20 316-322
• 35 Bolton C F, Young G B, Zochodne D W. The neurological complications of sepsis.  Ann Neurol. 1993;  33 94-100
• 36 Hanson P, Dive A, Brucher J M, Bisteau M, Dangoisse M, Deltombe T. Acute corticosteroid myopathy in intensive care patients.  Muscle Nerve. 1997;  20 1371-1380
• 37 Zochodne D W, Ramsay D A, Saly V, Shelley S, Moffatt S. Acute necrotizing myopathy of intensive care: electrophysiological studies.  Muscle Nerve. 1994;  17 285-292
• 38 Campellone J V. Respiratory muscle weakness in patients with critical illness neuromyopathies: a practical assessment.  Crit Care Med. 2007;  35 2205-2206
• 39 Douglass J A, Tuxen D V, Horne M et al.. Myopathy in severe asthma.  Am Rev Respir Dis. 1992;  146 517-519
• 40 Shee C D. Risk factors for hydrocortisone myopathy in acute severe asthma.  Respir Med. 1990;  84 229-233
• 41 Riggs J E, Pandey H K, Schochet Jr S S. Critical illness myopathy associated with hyperthyroidism.  Mil Med. 2004;  169 71-72
• 42 Road J, Mackie G, Jiang T X, Stewart H, Eisen A. Reversible paralysis with status asthmaticus, steroids, and pancuronium: clinical electrophysiological correlates.  Muscle Nerve. 1997;  20 1587-1590
• 43 Zochodne D W, Bolton C F, Wells G A et al.. Critical illness polyneuropathy. A complication of sepsis and multiple organ failure.  Brain. 1987;  110(Pt 4) 819-841
• 44 Bolton C F, Gilbert J J, Hahn A F, Sibbald W J. Polyneuropathy in critically ill patients.  J Neurol Neurosurg Psychiatry. 1984;  47(11) 1223-1231
• 45 Tennilä A, Salmi T, Pettilä V, Roine R O, Varpula T, Takkunen O. Early signs of critical illness polyneuropathy in ICU patients with systemic inflammatory response syndrome or sepsis.  Intensive Care Med. 2000;  26 1360-1363
• 46 Sander H W, Golden M, Danon M J. Quadriplegic areflexic ICU illness: selective thick filament loss and normal nerve histology.  Muscle Nerve. 2002;  26 499-505
• 47 Garnacho-Montero J, Amaya-Villar R, García-Garmendía J L, Madrazo-Osuna J, Ortiz-Leyba C. Effect of critical illness polyneuropathy on the withdrawal from mechanical ventilation and the length of stay in septic patients.  Crit Care Med. 2005;  33 349-354
• 48 Latronico N, Peli E, Botteri M. Critical illness myopathy and neuropathy.  Curr Opin Crit Care. 2005;  11 126-132
• 49 Bercker S, Weber-Carstens S, Deja M et al.. Critical illness polyneuropathy and myopathy in patients with acute respiratory distress syndrome.  Crit Care Med. 2005;  33 711-715
• 50 Bolton C F. Neuromuscular manifestations of critical illness.  Muscle Nerve. 2005;  32 140-163
• 51 Bednarik J, Lukas Z, Vondracek P. Critical illness polyneuromyopathy: the electrophysiological components of a complex entity.  Intensive Care Med. 2003;  29 1505-1514
• 52 Khan J, Harrison T B, Rich M M, Moss M. Early development of critical illness myopathy and neuropathy in patients with severe sepsis.  Neurology. 2006;  67 1421-1425
• 53 Latronico N, Fenzi F, Recupero D et al.. Critical illness myopathy and neuropathy.  Lancet. 1996;  347 1579-1582
• 54 Di Giovanni S, Molon A, Broccolini A et al.. Constitutive activation of MAPK cascade in acute quadriplegic myopathy.  Ann Neurol. 2004;  55 195-206
• 55 Capasso M, Di Muzio A, Pandolfi A et al.. Possible role for nitric oxide dysregulation in critical illness myopathy.  Muscle Nerve. 2008;  37 196-202
• 56 Rossignol B, Gueret G, Pennec J P et al.. Effects of chronic sepsis on the voltage-gated sodium channel in isolated rat muscle fibers.  Crit Care Med. 2007;  35 351-357
• 57 Rich M M, Pinter M J. Crucial role of sodium channel fast inactivation in muscle fibre inexcitability in a rat model of critical illness myopathy.  J Physiol. 2003;  547(Pt 2) 555-566
• 58 de Letter M A, Schmitz P I, Visser L H et al.. Risk factors for the development of polyneuropathy and myopathy in critically ill patients.  Crit Care Med. 2001;  29 2281-2286
• 59 van den Berghe G, Wouters P, Weekers F et al.. Intensive insulin therapy in the critically ill patients.  N Engl J Med. 2001;  345 1359-1367
• 60 De Jonghe B, Bastuji-Garin S, Sharshar T, Outin H, Brochard L. Does ICU-acquired paresis lengthen weaning from mechanical ventilation?.  Intensive Care Med. 2004;  30 1117-1121
• 61 De Jonghe B, Bastuji-Garin S, Durand M-C Groupe de Réflexion et d’Etude des Neuromyopathies en Réanimation et al. Respiratory weakness is associated with limb weakness and delayed weaning in critical illness.  Crit Care Med. 2007;  35 2007-2015
• 62 Leijten F S, Harinck-de Weerd J E, Poortvliet D C, de Weerd A W. The role of polyneuropathy in motor convalescence after prolonged mechanical ventilation.  JAMA. 1995;  274 1221-1225
• 63 Garnacho-Montero J, Madrazo-Osuna J, García-Garmendia J L et al.. Critical illness polyneuropathy: risk factors and clinical consequences. A cohort study in septic patients.  Intensive Care Med. 2001;  27 1288-1296
• 64 Ali N A, O’Brien Jr J M, Hoffmann S P Midwest Critical Care Consortium et al. Acquired weakness, handgrip strength, and mortality in critically ill patients.  Am J Respir Crit Care Med. 2008;  178 261-268
• 65 Fletcher S N, Kennedy D D, Ghosh I R et al.. Persistent neuromuscular and neurophysiologic abnormalities in long-term survivors of prolonged critical illness.  Crit Care Med. 2003;  31 1012-1016
• 66 Guarneri B, Bertolini G, Latronico N. Long-term outcome in patients with critical illness myopathy or neuropathy: the Italian multicentre CRIMYNE study.  J Neurol Neurosurg Psychiatry. 2008;  79 838-841
• 67 Latronico N, Guarneri B. Critical illness myopathy and neuropathy.  Minerva Anestesiol. 2008;  74 319-323
• 68 Lacomis D, Zochodne D W, Bird S J. Critical illness myopathy.  Muscle Nerve. 2000;  23 1785-1788
• 69 Latronico N, Shehu I, Seghelini E. Neuromuscular sequelae of critical illness.  Curr Opin Crit Care. 2005;  11 381-390
• 70 van der Schaaf M, Beelen A, de Vos R. Functional outcome in patients with critical illness polyneuropathy.  Disabil Rehabil. 2004;  26 1189-1197
• 71 Bolton C F, Laverty D A, Brown J D, Witt N J, Hahn A F, Sibbald W J. Critically ill polyneuropathy: electrophysiological studies and differentiation from Guillain-Barré syndrome.  J Neurol Neurosurg Psychiatry. 1986;  49 563-573
• 72 Latronico N. Neuromuscular alterations in the critically ill patient: critical illness myopathy, critical illness neuropathy, or both?.  Intensive Care Med. 2003;  29 1411-1413
• 73 Zifko U A. Long-term outcome of critical illness polyneuropathy.  Muscle Nerve Suppl. 2000;  9 S49-S52
• 74 Beasley W C. Quantitative muscle testing: principles and applications to research and clinical services.  Arch Phys Med Rehabil. 1961;  42 398-425
• 75 Herridge M S, Cheung A M, Tansey C M Canadian Critical Care Trials Group et al. One-year outcomes in survivors of the acute respiratory distress syndrome.  N Engl J Med. 2003;  348 683-693
• 76 Cheung A M, Tansey C M, Tomlinson G et al.. Two-year outcomes, health care use, and costs of survivors of acute respiratory distress syndrome.  Am J Respir Crit Care Med. 2006;  174 538-544
• 77 Niskanen M, Ruokonen E, Takala J, Rissanen P, Kari A. Quality of life after prolonged intensive care.  Crit Care Med. 1999;  27 1132-1139
• 78 Schelling G, Stoll C, Vogelmeier C et al.. Pulmonary function and health-related quality of life in a sample of long-term survivors of the acute respiratory distress syndrome.  Intensive Care Med. 2000;  26 1304-1311
• 79 Douglas S L, Daly B J, Gordon N, Brennan P F. Survival and quality of life: short-term versus long-term ventilator patients.  Crit Care Med. 2002;  30 2655-2662
• 80 Storch E K, Kruszynski D M. From rehabilitation to optimal function: role of clinical exercise therapy.  Curr Opin Crit Care. 2008;  14 451-455
• 81 Dubois M-J, Bergeron N, Dumont M, Dial S, Skrobik Y. Delirium in an intensive care unit: a study of risk factors.  Intensive Care Med. 2001;  27 1297-1304
• 82 Ely E W, Gautam S, Margolin R et al.. The impact of delirium in the intensive care unit on hospital length of stay.  Intensive Care Med. 2001;  27 1892-1900
• 83 Ely E W, Inouye S K, Bernard G R et al.. Delirium in mechanically ventilated patients: validity and reliability of the confusion assessment method for the intensive care unit (CAM-ICU).  JAMA. 2001;  286 2703-2710
• 84 Griffiths R D, Jones C. Delirium, cognitive dysfunction and posttraumatic stress disorder.  Curr Opin Anaesthesiol. 2007;  20 124-129
• 85 Inouye S K. Delirium in older persons.  N Engl J Med. 2006;  354 1157-1165
• 86 Milbrandt E B, Angus D C. Bench-to-bedside review: critical illness-associated cognitive dysfunction—mechanisms, markers, and emerging therapeutics.  Crit Care. 2006;  10 238-246
• 87 Hopkins R O, Weaver L K, Pope D, Orme J F, Bigler E D, Larson-LOHR V. Neuropsychological sequelae and impaired health status in survivors of severe acute respiratory distress syndrome.  Am J Respir Crit Care Med. 1999;  160 50-56
• 88 Rattray J E, Hull A M. Emotional outcome after intensive care: literature review.  J Adv Nurs. 2008;  64 2-13
• 89 Jones C, Griffiths R D, Slater T, Benjamin K S, Wilson S. Significant cognitive dysfunction in non-delirious patients identified during and persisting following critical illness.  Intensive Care Med. 2006;  32 923-926
• 90 Rubenfeld G D. Interventions to improve long-term outcomes after critical illness.  Curr Opin Crit Care. 2007;  13 476-481
• 91 Winkelman C, Higgins P A, Chen Y-JK. Activity in the chronically critically ill.  Dimens Crit Care Nurs. 2005;  24 281-290
• 92 Morris P E, Goad A, Thompson C et al.. Early intensive care unit mobility therapy in the treatment of acute respiratory failure.  Crit Care Med. 2008;  36 2238-2243
• 93 Needham D M, Wang W, Desai S V et al.. Intensive care unit exposures for long-term outcomes research: development and description of exposures for 150 patients with acute lung injury.  J Crit Care. 2007;  22 275-284
• 94 Hodgin K E, Nordon-Craft A, McFann K K, Mealer M L, Moss M. Physical therapy utilization in intensive care units: results from a national survey.  Crit Care Med. 2009;  37 561-566, quiz 566–568
• 95 Bailey P, Thomsen G E, Spuhler V J et al.. Early activity is feasible and safe in respiratory failure patients.  Crit Care Med. 2007;  35 139-145
• 96 Gosselink R, Bott J, Johnson M et al.. Physiotherapy for adult patients with critical illness: Recommendations of the European Respiratory Society and European Society of Intensive Care Medicine task force on physiotherapy for critically ill patients.  Intensive Care Med. 2008;  34 1188-1199
• 97 Ball C. Improving rehabilitation following transfer from ICU.  Intensive Crit Care Nurs. 2008;  24 209-210
• 98 Martin U J, Hincapie L, Nimchuk M, Gaughan J, Criner G J. Impact of whole-body rehabilitation in patients receiving chronic mechanical ventilation.  Crit Care Med. 2005;  33 2259-2265
• 99 Nava S. Rehabilitation of patients admitted to a respiratory intensive care unit.  Arch Phys Med Rehabil. 1998;  79 849-854
• 100 Martin U J. Whole-body rehabilitation in long-term ventilation.  Respir Care Clin N Am. 2002;  8 593-609
• 101 Perme C S, Southard R E, Joyce D L, Noon G P, Loebe M. Early mobilization of LVAD recipients who require prolonged mechanical ventilation.  Tex Heart Inst J. 2006;  33 130-133
• 102 Jarrett S R, Mogelof J S. Critical illness neuropathy: diagnosis and management.  Arch Phys Med Rehabil. 1995;  76 688-691
• 103 Nagaratnam N, Jamieson G, Chiu K, Ramos C. Critical illness neuropathy.  Neurorehabil Neural Repair. 2001;  15 81-84
• 104 Hopkins R O, Spuhler V J, Thomsen G E. Transforming ICU culture to facilitate early mobility.  Crit Care Clin. 2007;  23 81-96
• 105 Stiller K, Phillips A C, Lambert P. The safety of mobilization and its effects on haemodynamic and respiratory status of intensive care patients.  Physiother Theory Pract. 2004;  20 175-185
• 106 Sciaky A J. Mobilizing the intensive care unit patient: pathophysiology and treatment.  Physiother Theory Pract. 1994;  3 69-80
• 107 Thomsen G E, Snow G L, Rodriguez L, Hopkins R O. Patients with respiratory failure increase ambulation after transfer to an intensive care unit where early activity is a priority.  Crit Care Med. 2008;  36 1119-1124
• 108 Tan T, Brett S J, Stokes T. Guideline Development Group . Rehabilitation after critical illness: summary of NICE guidance.  BMJ. 2009;  338 b822
• 109 Schweickert W D, Pohlman M C, Pohlman A S et al.. Early physical and occupational therapy in mechanically ventilated, critically ill patients: a randomised, controlled trial.  Lancet. 2009;  373 1874-1882
• 110 Zanotti E, Felicetti G, Maini M, Fracchia C. Peripheral muscle strength training in bed-bound patients with COPD receiving mechanical ventilation: effect of electrical stimulation.  Chest. 2003;  124 292-296
• 111 Aldrich T K, Karpel J P, Uhrlass R M, Sparapani M A, Eramo D, Ferranti R. Weaning from mechanical ventilation: adjunctive use of inspiratory muscle resistive training.  Crit Care Med. 1989;  17 143-147
• 112 Bissett B, Leditschke I A. Inspiratory muscle training to enhance weaning from mechanical ventilation.  Anaesth Intensive Care. 2007;  35 776-779
• 113 Sprague S S, Hopkins P D. Use of inspiratory strength training to wean six patients who were ventilator-dependent.  Phys Ther. 2003;  83 171-181
• 114 Martin A D, Davenport P D, Franceschi A C, Harman E. Use of inspiratory muscle strength training to facilitate ventilator weaning: a series of 10 consecutive patients.  Chest. 2002;  122 192-196
• 115 Chang A T, Boots R J, Henderson R, Paratz J D, Hodges P W. Case report: inspiratory muscle training in chronic critically ill patients—a report of two cases.  Physiother Res Int. 2005;  10 222-226
• 116 Caruso P, Denari S DC, Ruiz S AL et al.. Inspiratory muscle training is ineffective in mechanically ventilated critically ill patients.  Clinics (Sao Paulo). 2005;  60 479-484
• 117 Hermans G, Wilmer A, Meersseman W et al.. Impact of intensive insulin therapy on neuromuscular complications and ventilator dependency in the medical intensive care unit.  Am J Respir Crit Care Med. 2007;  175 480-489
• 118 Ginzburg E, Banovac K, Epstein B, Nedd K, Rolnick M, Tannenbaum S. Thromboprophylaxis in medical and surgical patients undergoing physical medicine and rehabilitation: consensus recommendations.  Am J Phys Med Rehabil. 2006;  85 159-166
• 119 Mechanick J I, Brett E M. Nutrition and the chronically critically ill patient.  Curr Opin Clin Nutr Metab Care. 2005;  8 33-39
• 120 Miles J M. Energy expenditure in hospitalized patients: implications for nutritional support.  Mayo Clin Proc. 2006;  81 809-816
• 121 Friese R S. Good night, sleep tight: the time is ripe for critical care providers to wake up and focus on sleep.  Crit Care. 2008;  12 146-147
• 122 Morris P E, Herridge M S. Early intensive care unit mobility: future directions.  Crit Care Clin. 2007;  23 97-110
• 123 Aichenbaum S R, Ring H. Rehabilitation of a patient with critical illness polyneuropathy (CIP) following acute respiratory failure: a case report and review of literature.  Disabil Rehabil. 2003;  25 273-276
• 124 Jones C, Skirrow P, Griffiths R D et al.. Rehabilitation after critical illness: a randomized, controlled trial.  Crit Care Med. 2003;  31 2456-2461
• 125 Weissman C, Kemper M. Stressing the critically ill patient: the cardiopulmonary and metabolic responses to an acute increase in oxygen consumption.  J Crit Care. 1993;  8 100-108
• 126 Vitacca M, Bianchi L, Sarvà M, Paneroni M, Balbi B. Physiological responses to arm exercise in difficult to wean patients with chronic obstructive pulmonary disease.  Intensive Care Med. 2006;  32 1159-1166
• 127 McMahon M M, Benotti P N, Bistrian B R. A clinical application of exercise physiology and nutritional support for the mechanically ventilated patient.  JPEN J Parenter Enteral Nutr. 1990;  14 538-542