Effects of manual hyperinflation in preterm newborns under mechanical ventilation

Abstract

ObjectiveTo assess the effects of manual hyperinflation, performed with a manual resuscitator with and without the positive end-expiratory pressure valve, on the respiratory function of preterm newborns under mechanical ventilation.MethodsCross-sectional study of hemodynamically stable preterm newborns with gestational age of less than 32 weeks, under mechanical ventilation and dependent on it at 28 days of life. Manual hyperinflation was applied randomly, alternating the use or not of the positive end-expiratory pressure valve, followed by tracheal aspiration for ending the maneuver. For nominal data, the two-tailed Wilcoxon test was applied at the 5% significance level and 80% power.ResultsTwenty-eight preterm newborns, with an average birth weight of 1,005.71 ± 372.16g, an average gestational age of 28.90 ± 1.79 weeks, an average corrected age of 33.26 ± 1.78 weeks, and an average mechanical ventilation time of 29.5 (15 - 53) days, were studied. Increases in inspiratory and expiratory volumes occurred between time-points A5 (before the maneuver) and C1 (immediately after tracheal aspiration) in both the maneuver with the valve (p = 0.001 and p = 0.009) and without the valve (p = 0.026 and p = 0.001), respectively. There was also an increase in expiratory resistance between time-points A5 and C1 (p = 0.044).ConclusionLung volumes increased when performing the maneuver with and without the valve, with a significant difference in the first minute after aspiration. There was a significant difference in expiratory resistance between the time-points A5 (before the maneuver) and C1 (immediately after tracheal aspiration) in the first minute after aspiration within each maneuver.

Manual hyperinflation in children

“…Only the study by Viana et al. ( 17 ) included a sample calculation. Soudararajan et al ( 18 ) obtained a convenience sample, Novais de Oliveira et al ( 19 ) based their sample size on previous studies, and the other studies (Gregson et al, de Oliveira et al and Koop et al) did not address this issue.…”

“…Briefly, the interventions performed involved the use of MH with or without the use of positive end expiratory pressure (PEEP) valve, ( 17 ) MH with thoracic vibrocompression (TVC), ( 18 ) and an analysis of the performance of three manual resuscitators from different manufacturers in terms of the ventilatory data of two test lungs (neonatal and pediatric) with different oxygen flow rates. ( 20 ) In addition, the influence of professional experience on MH performance, ( 19 ) the contribution of TVC to the increase in expiratory flow during MH ( 5 ) and the clinical variables after MH was performed were analyzed.…”

“…Regarding the method of application of the maneuver, four studies mentioned thus of slow insufflation with and inspiratory pause ranging from 2 to 3 seconds, followed by rapid release during the expiratory phase. ( 17 , 19 - 21 ) Three studies reported the use of chest compressions during expiration. ( 17 , 18 , 21 ) Only one study did not mention the method of application of MH.…”

“…( 17 , 19 - 21 ) Three studies reported the use of chest compressions during expiration. ( 17 , 18 , 21 ) Only one study did not mention the method of application of MH. ( 5 )…”

“…( 18 ) Gregson et al, Viana et al, Novais de Oliveira et al and de Oliveira et al focused mainly on ventilatory data, such as inspiratory pulmonary volume (PVinsp), expiratory lung volume (PVexp), inspiratory pulmonary resistance (PRinsp), expiratory pulmonary resistance (PRexp), tidal volume (Vt), inspiratory pressure peak, PIF, PEF and inspiratory time (Tinsp). ( 5 , 17 , 19 , 20 ) Only Gregson et al evaluated the force applied by the operator during chest compressions in MH. ( 5 )…”