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Ventilator-derived VCO
2
measurements to determine REE
59
3
The statistical analyses were performed using IBM SPSS statistics 21 forWindows (IBM, Chicago
IL, USA). All statistical tests were two-sided and statistical significance was defined as a p-value
<0.05.
RESULTS
Measurements were performed in 41 children, themedian age was 2.3 years (IQR 0.3 to 8.4) and
56% were male. Seventy-two percent of the children were admitted with a medical diagnosis,
mostly due to respiratory insufficiency (39%). Patient characteristics are shown in Table 1a. A
controlled ventilation mode was used in 66% of the children; median fractional inspired O
2
was 0.26 (IQR 0.21 to 0.31). Metabolic measurements, performed on the 2
nd
day of ICU stay
(median), lasted 30 minutes on average. Ventilator settings and metabolic measurement data
are shown in Table 1b.
Table 1a.
Patient characteristics for all children and for subgroups based on compatibility of the indirect
calorimetry (IC) and ventilator method (defined as a difference ≤10% or >10% between IC and ventilator-
derived VCO
2
values
All children
N=41
Difference ≤10%
N=18
Difference >10%
N=23
P-value
Age (yr)
Age < 3 year
Median (IQR)
%
2.3 (0.3-8.4)
51.2
7.4 (3.3-11.9)
22.2
0.6 (0.2-4.6)
73.9
<0.001
b
0.002
c
Male sex
%
56.1
55.6
56.5
0.95
c
Weight (kg)
Weight < 10 kg
Median (IQR)
%
12.7 (6.1-28.5)
46.3
22.5 (14-41.8)
16.7
6.3 (4.6-16)
69.6
0.001
b
0.002
c
Height (cm)
Median (IQR)
88
(63-135)
121
(103-150)
65
(54-98)
<0.001
b
Diagnosis
Surgery
Medical
- Respiratory
%
29.3
71.7
38.7
27.8
72.2
30.4
69.6
0.85
c
PRISM score
Median (IQR)
10 (5-16)
12 (7-16)
9 (5-17)
0.44
b
LOS ICU (days)
Median (IQR)
7 (4-17)
9 (4-24)
7 (4-11)
0.76
b
Survival
%
92.7
94.4
91.3
0.70
c
Temperature (ºC)
Mean ± SD 37.3 ± 1.0
37.6 ± 1.2
37.1 ± 0.7
0.18
a
Use of medication
Sedatives
Catecholamines
Muscle relaxants
Beta blockers
%
87.8
24.4
7.3
0
88.9
27.8
11.1
0
87.0
21.7
4.3
0
0.85
c
0.66
c
0.41
c
1.00
c
P-values are calculated for differences between the two subgroups using the following tests:
a
Independent
samples t-test,
b
Mann-Whitney test,
c
Chi-square test.
IQR= Interquartile Range, PRISM= Paediatric Risk of Mortality, LOS= Length of Stay, ICU= Intensive Care
Unit, SD= Standard Deviation