40D / 208 – INCREASED FUNCTIONAL RESIDUAL
UNIVENTRICULAR HEART PHYSIOLOGY.
LS Nordhagen, IL Matthews, E Thaulow, M Grønn.
Rikshospitalet - Oslo (Norway)
CAPACITY
IN
INFANTS
WITH
Background: Our previous research in infants with Univentricular hearts (UVH) has shown decreased
tidal lung volume and compliance of the respiratory system measured soon after birth and improving
with age and after surgical treatment .Commercially available equipment can measure functional
residual capacity (FRC) and ventilation inhomogeneity. Measurement of these can improve our
understanding of lung physiology in children with UVH hearts.
Objective: Compare FRC and ventilation inhomogeneity in children with UVH versus healthy children,
soon after birth and between 3 and 9 months of age.
Methods: 17 newborn infants with UVH and 23 healthy newborn infants had their FRC and ventilation
inhomogeneity measured during natural sleep. The test was repeated between 3-9 months of age in
14 children with UVH and 16 healthy children.
All the children were recruited from the National Hospital. FRC and ventilation inhomogeneity was
measured with a multiple breath washout technique. An ultrasonic device measures the flow and
change in molar mass by using SF6 as a tracer gas.
Results: The table shows mean, median, 95% Confidence intervals, minimum, maximum and p-value
Age(days)
Weight (kg)
SPO2 (%)
FRC (ml/kg)
MR0
MR1
MR2
LCI
Age(days)
Weight (kg)
SPO2 (%)
FRC (ml/kg)
MR0
MR1
MR2
LCI
Healthy newborn infants
(n=23)
Mean (95%CI)
Median (min, max)”
3(3,4)”
3.4(3.2,3.6)
99(95,100)”
21.2(19.5,23.0)
1.7(1.5,2.1)”
3.6(2.1,5.8)”
12(7.2,28)”
9.1(6.9,10.0)”
Healthy infants
(3-9 months old) n=16
Mean (95%CI)
Median (min, max)”
111.5(80,229)”
6.7(6.0,7.4)
99 (97,100)”
17.6(15.3,19.9)
1.5(1.3,2.1)”
3.1(2.2,5.6)”
13.4(7.7,29.5)”
8.3(6.3,10.0)”
Newborn infants with
(n=17)
Mean (95%CI)
Median (min, max)”
3(3,9)”
3.4(3.1,3.7)
92(55,99)”
21.0(19.4,22.6)
1.9(1.3,2.4)”
3.7(2.2,8.3)”
16(7.2,50.1)”
9.3(6.9,12.6)”
Infants with UVH
(3-9 months old) n=14
Mean (95%CI)
Median (min, max)”
122.5(92,265)”
6.5(5.9,7.0)
74.5(57,88)”
22.7(20.2,25.3)
1.6(1.3,1.9)”
3.0(2.0,5.6)”
14.3(6.5,29.6)”
8.3(7.0,10.5)”
UVH
p-value*
0.034*
0.677
<0.001*
0.835
0.137
0.902
0.244
0.147
p-value*
0.190
0.594
<0.001*
0.003*
0.626
0.338
0.868
0.886
Abbreviations: UVH univentricular hearts, FRC functional residual capacity, MR moment ratios, LCI lung clearing index.
There was no significant difference in FRC, moment ratios (MR) and lung clearing index (LCI)
measured soon after birth, although there was a tendency for a higher LCI in the infants with UVH
(p=0.09). At 3 to 6 mounts of age the infants with UVH had a higher FRC than the healthy infants.
Conclusion: infants with Univentricular hearts aged 3 to 9 months have increased FRC which may
indicate gas trapping, similar to our previous findings in children 8 to 16 years of age.