title: A repeated measures, randomised cross-over trial, comparing the acute exercise response between passive and active sitting in critically ill patients.
abstract: BACKGROUND
  Early mobilisation of critically ill patients is safe and beneficial, but the metabolic cost of exercise remains unquantified. This study compared the acute exercise response in critically ill participants during passive and active sitting.
  
  
  METHODS
  We conducted a prospective, randomised, cross-over study, in ventilated patients receiving rehabilitative physiotherapy. Ten participants completed a passive chair transfer, or a sit on the edge of the bed, followed by the alternate exercise activity on the consecutive day. The primary outcome measure was oxygen consumption.
  
  
  RESULTS
  In comparison to resting supine, a passive chair transfer elicited no change in oxygen consumption, carbon dioxide production or minute ventilation; but mean arterial pressure (91.86 mmHg (95% CI 84.61 to 99.10) to 101.23 mmHg (95% CI 93.35 to 109.11) (p = 0.002)) and heart rate (89.13 bpm (95% CI 77.14 to 101.13) to 97.21 bpm (95% CI 81.22 to 113.20) (p = 0.008)) increased. Sitting on the edge of the bed resulted in significant increases in oxygen consumption (262.33 ml/min (95% CI 201.97 to 322.70) to 353.02 ml/min (95% CI 303.50 to 402.55), p = 0.002), carbon dioxide production (171.93 ml/min (95% CI 131.87 to 211.98) to 206.23 ml/min (95% CI 151.03 to 261.43), p = 0.026), minute ventilation (9.97 l/min (95% CI 7.30 to 12.65) to 12.82 l/min (95% CI 10.29 to 15.36), p < 0.001), mean arterial pressure (86.81 mmHg (95% CI 77.48 to 96.14) to 95.59 mmHg (95% CI 88.62 to 102.56), p = 0.034) and heart rate (87.60 bpm (95% CI 73.64 to 101.56) to 94.91 bpm (95% CI 79.57 to 110.25), p = 0.007). When comparing the 2 activities, sitting on the edge of the bed elicited a significantly larger increase in oxygen consumption (90.69 ml/min (95% CI 44.04 to 137.34) vs 14.43 ml/min (95% CI -27.28 to 56.14), p = 0.007) and minute ventilation (2.85 l/min (95% CI 1.70 to 3.99) vs 0.74 l/min (95% CI -0.92 to 1.56), p = 0.012).
  
  
  CONCLUSIONS
  Sitting on the edge of the bed is a more metabolically demanding activity than a passive chair transfer in critically ill patients.
authors: Department of Physiotherapy, University Hospital Southampton NHS Foundation Trust, Tremona Road, SO16 6YD Southampton, UK ; Anaesthesia and Critical Care Research Unit, University Hospital Southampton NHS Foundation Trust, Tremona Road, SO16 6YD Southampton, UK ; Integrative Physiology and Critical Illness Group, Clinical and Experimental Sciences, University of Southampton, University Hospital Southampton, Tremona Road, SO16 6YD Southampton, UK.
authors: Nikki
authors: N
authors: Collings
authors: Anaesthesia and Critical Care Research Unit, University Hospital Southampton NHS Foundation Trust, Tremona Road, SO16 6YD Southampton, UK ; Integrative Physiology and Critical Illness Group, Clinical and Experimental Sciences, University of Southampton, University Hospital Southampton, Tremona Road, SO16 6YD Southampton, UK ; Southampton NIHR Respiratory Biomedical Research Unit, University Hospital Southampton, Tremona Road, SO16 6YD Southampton, UK.
authors: Rebecca
authors: R
authors: Cusack
mesh_terms: D001794:Blood Pressure / Q000502:physiology; D002245:Carbon Dioxide / Q000378:metabolism; D016638:Critical Illness / Q000534:rehabilitation*; D018592:Cross-Over Studies; D004434:Early Ambulation; D015444:Exercise / Q000502:physiology*; D005081:Exercise Therapy; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D011187:Posture / Q000502:physiology*; D012123:Pulmonary Ventilation / Q000502:physiology
chemical_list: D002245:Carbon Dioxide
keywords: Critical illness; Early ambulation; Exercise; Oxygen consumption; Physiotherapy; Rehabilitation