title: [Effect of changes in body weight on rest energy expenditure in critically ill patients].
abstract: OBJECTIVE
  Critically ill patients may present rapid and significant variations in body weight in excess of 20%, attributed to acute changes in the volume of extracellular water. These changes should not alter the level of metabolic activity, as the extracellular compartment is metabolically inactive. The purpose of this study has been to verify whether or not the rapid changes in body weight presented by critically ill patients over short periods of time alter the at-rest energy expenditure (GER in its Spanish acronym).
  
  
  METHODS
  Out of a group of 55 critically ill patients whose GER had been repeatedly measured, 15 were chosen as two of their GER measurements complied with the following clinical conditions: a difference in body weight of more than 5%, a time difference of less than 10 days between both measurements, a variation of less than 20% in the calorie intake, a difference in axillary temperature of less than 1 degree centigrade (degree C) and the same sedation and/or analgesia. All of the patients presented acute kidney failure. Their GER was measured with a system based on the bell spirometer (Calorimet).
  
  
  RESULTS
  The variation in body weight was 7.3 +/- 2.12 kg. The difference between the GER with high and low body weight was, in absolute terms, 154 +/- 162 kcal/day (p = 0.003) and, in terms of body weight, -0.6 +/- 1.9 kcal/kg/day (p = 0.21). A statistically significant (r = 0.77 and p > 0.001) linear relationship was observed between the variations in body weight and the GER expressed as a percentage [[symbol: see text] GER (%) = -1.77 + [symbol: see text] peso (%)].
  
  
  CONCLUSIONS
  The variation in body weight presented by critically ill patients over short periods of time is associated with changes in the GER.
authors.affiliation: Servicio de Medicina Intensiva, Hospital Son Dureta, Palma de Mallorca.
authors.forename: J M
authors.initials: JM
authors.lastname: Raurich
authors.forename: J
authors.initials: J
authors.lastname: Ibáñez
authors.forename: P
authors.initials: P
authors.lastname: Marsé
mesh_terms: D001835:Body Weight; D016638:Critical Illness; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D008297:Male; D012146:Rest / Q000502:physiology*