Results of airway clearance techniques in respiratory mechanics of preterm neonates under mechanical ventilation.

OBJECTIVES This research aimed to evaluate the repercussions of specific chest physiotherapy procedures in mean airway resistance and in dynamic compliance in preterm infants in mechanical ventilation. METHODS Eighteen preterm infants in conventional mechanical ventilation were submitted to one session of chest physiotherapy (manual chest compression during expiration + intermittent aspiration of intratracheal cannula). Mean airway resistance and dynamic compliance measurements were taken prior to, 10, 40 and 70 minutes after intervention using a pneumotachograph with graphic display (Newport Navigator GM-250®), coupled to a flow transducer (Varfley-Bicore®). For analysis of results the infants were divided into 2 groups; less than 5 days (group mechanical ventilation <5) and 5 days or more (group mechanical ventilation >5) on mechanical ventilation. Values were analyzed by Friedman Test, with Dunn's Multiple Comparisons Test (p<0,05 significant). RESULTS In group mechanical ventilation <5 a significant reduction of mean airway resistance was observed at the 10th minute after intervention (p<0,05). There were no significant alterations in dynamic compliance. The group mechanical ventilation >5 mean airway resistance had a significant reduction at the 10th (p<0,001), 40th (p<0,05) and 70th (p<0,05) minute after intervention. The dynamic compliance improved significantly only at the 10th minute (p<0,05). CONCLUSIONS The airway clearance techniques used in preterm neonates under conventional mechanical ventilation >5 improved mean airway resistance and dynamic compliance, with best results for the mean airway resistance.