Resting energy expenditure, calorie and protein consumption in critically ill patients: a retrospective cohort study

Abstract

BackgroundIntense debate exists regarding the optimal energy and protein intake for intensive care unit (ICU) patients. However, most studies use predictive equations, demonstrated to be inaccurate to target energy intake. We sought to examine the outcome of a large cohort of ICU patients in relation to the percent of administered calories divided by resting energy expenditure (% AdCal/REE) obtained by indirect calorimetry (IC) and to protein intake.MethodsIncluded patients were hospitalized from 2003 to 2015 at a 16-bed ICU at a university affiliated, tertiary care hospital, and had IC measurement to assess caloric targets. Data were drawn from a computerized system and included the % AdCal/REE and protein intake and other variables. A Cox proportional hazards model for 60-day mortality was used, with the % AdCal/REE modeled to accommodate non-linearity. Length of stay (LOS) and length of ventilation (LOV) were also assessed.ResultsA total of 1171 patients were included. The % AdCal/REE had a significant non-linear (p < 0.01) association with mortality after adjusting for other variables (p < 0.01). Increasing the percentage from zero to 70 % resulted in a hazard ratio (HR) of 0.98 (CI 0.97–0.99) pointing to reduced mortality, while increases above 70 % suggested an increase in mortality with a HR of 1.01 (CI 1.01–1.02). Increasing protein intake was also associated with decreased mortality (HR 0.99, CI 0.98–0.99, p = 0.02). An AdCal/REE >70 % was associated with an increased LOS and LOV.ConclusionsThe findings of this study suggest that both underfeeding and overfeeding appear to be harmful to critically ill patients, such that achieving an Adcal/REE of 70 % had a survival advantage. A higher caloric intake may also be associated with harm in the form of increased LOS and LOV. The optimal way to define caloric goals therefore requires an exact estimate, which is ideally performed using indirect calorimetry. These findings may provide a basis for future randomized controlled trials comparing specific nutritional regimens based on indirect calorimetry measurements.

Feeding route or learning route for nutrition in critically ill

“…Based on current knowledge the early caloric delivery might be optimal at 70-90% of measured energy expenditure (4,5). In both NUTRIREA-2 and CALORIES trial only assumptions have been made on the individual caloric goal: 20-25 or 25 kcal/kg/day.…”

Muscle mass and physical recovery in ICU: innovations for targeting of nutrition and exercise

“…The accurate determination of caloric needs and objective measures of over-/under-feeding over time in critical care has long been a challenge for ICU practitioners and a recent large observational cohort has been conducted on this topic [32*]. Indirect calorimetry, despite its limitations in the hospital setting, has been traditionally utilized for estimating energy needs [32*].…”

“…Indirect calorimetry, despite its limitations in the hospital setting, has been traditionally utilized for estimating energy needs [32*]. The next evolution of modern indirect calorimetry is described in this issue by De Waele (REF) However, indirect calorimetry has traditionally proven expensive, has significant limitations in the ICU (i.e.…”

Timing of the initiation of parenteral nutrition in critically ill children

“…Furthermore, the use of equations to estimate total caloric goals, although practical, may not reflect accurate metabolic demands in the critically ill. Estimation of energy expenditure, as opposed to measuring metabolic needs with indirect calorimetry, could falsely over or under estimate caloric goals (16, 21). Overfeeding in PN, which typically occurs in the early phases of illness, could potentially contribute to unfavorable outcomes among those who received early PN initiation (18, 22).…”