title: Metabolic Requirement of Septic Shock Patients Before and After Liberation From Mechanical Ventilation.
abstract: This study identified the difference in energy expenditure and substrate utilization of patients during and upon liberation from mechanical ventilation.
  
  
  
  Patients under intensive care who were diagnosed with septic shock and dependent on mechanical ventilation were recruited. Indirect calorimetry measurements were performed during and upon liberation from mechanical ventilation.
  
  
  
  Thirty-five patients were recruited (20 men and 15 women; mean age, 69 ± 10 years). Measured energy expenditures during ventilation and upon liberation were 2090 ± 489 kcal·d-1and 1910 ± 579 kcal·d-1, respectively ( P < .05). Energy intake was provided at 1148 ± 495 kcal·d-1and differed significantly from all measured energy expenditures ( P < .05). Mean carbohydrate utilization was 0.19 ± 0.1 g·min-1when patients were on mechanical ventilation compared with 0.15 ± 0.09 g·min-1upon liberation ( P < .05). Mean lipid oxidation was 0.08 ± 0.05 g·min-1during and 0.09 ± 0.07 g·min-1upon liberation from mechanical ventilation ( P > .05).
  
  
  
  Measured energy expenditure was higher during than upon liberation from mechanical ventilation. This could be the increase in work of breathing from the continuous positive pressure support, repeated weaning cycles from mechanical ventilation, and/or the asynchronization between patients' respiration and ventilator support. Future studies should examine whether more appropriately matching energy expenditure with energy intake would promote positive health outcomes.
authors.affiliation: 1 Allied Health and Dietetics Department, United Christian Hospital, Hong Kong SAR, China.
authors.forename: Peggy Siu-Pik
authors.initials: PS
authors.lastname: Lee
authors.affiliation: 2 Intensive Care Department, United Christian Hospital, Hong Kong SAR, China.
authors.forename: Kar Lung
authors.initials: KL
authors.lastname: Lee
authors.affiliation: 3 Department for Health, University of Bath, UK.
authors.forename: James A
authors.initials: JA
authors.lastname: Betts
authors.affiliation: 2 Intensive Care Department, United Christian Hospital, Hong Kong SAR, China.
authors.forename: Kin Ip
authors.initials: KI
authors.lastname: Law
mesh_terms: D000368:Aged; D015992:Body Mass Index; D002153:Calorimetry, Indirect; D015331:Cohort Studies; D003422:Critical Care; D016638:Critical Illness / Q000628:therapy*; D002149:Energy Intake; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D018529:Nutritional Support; D012121:Respiration, Artificial; D012772:Shock, Septic / Q000378:metabolism* / Q000628:therapy*; D015300:Ventilator Weaning
keywords: indirect calorimetry; intensive care; measured energy expenditure; metabolic assessment; nutrition; research and diseases; sepsis; septic shock