1.2 Improvement of lung function
A retrospective study of pulmonary function in preterm infants found
that preterm infants born at less than 32 weeks may have significantly
reduced airflow during childhood and adolescence and that impairment of
pulmonary function was partially associated with the degree of BPD29. Young people with very low birth weight with
combined BPD have significantly reduced lung ventilation, as evidenced
by a low expiratory volume on exertion and reduced expiratory
volume/exertional lung volume in one second on
exertion30.Caffeine improves lung function by
increasing lung volume and airway compliance, decreases airway
resistance, improves respiratory muscle strength, and helps wean
premature infants from mechanical ventilation31. A
clinical study on the effect of caffeine treatment on pulmonary function
in preterm infants (birth weight <1500 g and gestational age
<31 weeks) showed that early caffeine treatment significantly
increased forced vital capacity(FVC) and forced expiratory volume(FEV)
by five-fold in preterm infants without BPD, while this trend remained
in preterm infants with BPD 32. Doyle et
al.demonstrated a significant effect of caffeine on expiratory flow ;a
group of patients who weighed less than 1250 g at birth, and did not
receive early caffeine treatment ,had a lower of expiratory forced
expired volume in 1 second (FEV1), FVC, and the forced expired flow from
25% to 75% of the FVC (FEF25-75%) at 11 years of
age33. Another study found that caffeine treatment
resulted in a sustained rapid increase in diaphragmatic activity and
tidal volume (VT) in preterm infants and that caffeine did not always
affect end-expiratory lung volume (EELV), respiratory rate, or
inspiratory and expiratory times34.
Caffeine treatment has also been shown to improve lung function by
increasing lung volume, total lung volume, and by improving lung
elasticity and compliance in a rabbit model35. In a
preliminary study, carried out in baboons, early caffeine treatment,
combined with prophylactic surfactant treatment, was found to improve
lung function over 24 hours by significantly reducing airway resistance
and increasing lung compliance36.