79 / 208
Use of indirect calorimetry to detect overfeeding
77
4
Figure 1.
Correlation between RQ-RQ
macr
and caloric intake/mREE (r=0.627, p<0.001). Dotted line
represents the generally applied cut-off value for overfeeding
RQ = Respiratory Quotient, mREE = measured Resting Energy Expenditure
DISCUSSION
This study showed that when different definitions indicating overfeeding were applied to a
group of critically ill mechanically ventilated children, a wide variation in the proportion of
children identified as overfed was found, ranging from 23% to 50%. RQ exceeded RQ
macr
+0.05
from a ratio caloric intake/mREE of 165%.
Overfeeding in critically ill children has been predominantly reported with the definition
based on the ratio caloric intake/REE (Table 1)
14,21-25,27,28
. The proposed and frequently used
upper limits of 110% or 120% are, however, consensus based and not derived from sound
studies with clinical endpoints. A recent systematic review in which 9 studies were summarized
and a recent single-center study by Jotterand Chaparro et al., investigated the influence of
energy and protein intake on protein balance in critically ill children. It was found that a
minimum
intake of respectively 57 and 58 kcal/kg/day and of 1.5 g protein/kg/day were
required to achieve a positive protein balance
19,20
. Taking into account a ratio caloric intake/
mREE >110% and >120%, a subgroup analysis of our study showed that 36% and 23% of the
children, respectively, did not achieve this minimal energy intake of 57 kcal/kg/day but would
be identified as being overfed. This identification of a patient as being overfed while they can
be presumed to have a negative protein balance would be a contradiction, regardless of the