Breathing intolerance index in healthy infants

Background The breathing intolerance index ( BITI ) is used to justify ventilator use in adult patients with pulmonary or chest wall disease. BITI in ventilated patients is mostly ≥0.15. The mean BITI of healthy adults in the upright sitting position and the supine position is 0.050 ± 0.009 and 0.057 ± 0.016, respectively. The aim of this study was to establish a normal BITI in infants. Methods Thirty healthy infants were examined in the supine position. BITI was defined as BITI = ( T i/ T tot) × ( TV / VC ), where T i is inspiratory time, Ttot is total breath cycle duration, TV is tidal volume, and VC is vital capacity. TV and T i/ T tot were obtained from tidal breathing at rest and VC was obtained spirometrically. BITI was calculated using customized software. Results The mean ± SD BITI of 30 healthy infants in the supine position was 0.120 ± 0.013. The BITI of infants was significantly higher than that of adults. Conclusions BITI was measured in healthy infants. Further evaluation is needed to determine the significance and usefulness of BITI .