Table 4

Relationships between daytime PaCO2 and clinic SpO2, body composition and lung volume at different levels of BMI

BMI>30 kg/m2
n=245
BMI>40 kg/m2
n=176
BMI>50 kg/m2
n=84
Rp ValueRp ValueRp Value
Correlation with PaCO2BMI (kg/m2)0.2540.0050.2180.0040.3510.001
SpO2 (%)−0.555<0.001−0.487<0.001−0.426<0.001
FVC−0.429<0.001−0.487<0.001−0.472<0.001
  • BMI, body mass index; FVC, forced vital capacity; PaCO2, arterial partial pressure of carbon dioxide; SpO2, oxygen saturation.