Influence of the “Squeeze Jacket” on Lung Function in Young Infants

Abstract

The possible influence of the "squeeze jacket" on measurements of lung function in young infants was examined in 29 infants. In 19 infants, a comparison was made between jacket off and jacket on with the arms held inside the jacket. With the jacket on (arms inside), we found a significant reduction in thoracic gas volume (TGV). Passive compliance of the respiratory system (Crs) was also significantly decreased, while the resistance of the respiratory system (Rrs) was significantly increased. An additional 10 infants were studied comparing jacket off with jacket on (arms outside) and jacket on (arms inside). TGV was significantly less with the jacket on (arms inside) compared to jacket off and jacket on (arms outside), while Rrs and mouth pressure at end-inspiratory occlusion (Pm) were significantly increased. There was no difference between jacket off and jacket on (arms outside). These observations suggest that the squeeze jacket with the arms held at the infant's side inside the jacket exerts a restricting effect on chest and abdominal wall movement and leads to errors in the measurements. To avoid these potential errors, measurements should be made without the jacket on or with the arms held outside the jacket.

Influence of jacket placement on respiratory compliance during raised lung volume measurements in infants

“…The latter was not measured in this study due to time constraints. A reduction of both compliance and lung volume during tidal breathing following jacket fastening was reported previously, 20 and it has been noted that even the placement of respiratory inductance bands may decrease C rs . 21 A few years ago, preliminary recommendations were made that the jacket should be applied loosely enough during the raised volume technique to allow full expansion of the chest without restriction, and that this could potentially be checked by measuring in¯ation volumes immediately prior to and after jacket placement.…”

A novel non-invasive technique for measuring the residual lung volume by nitrogen washout with rapid thoracoabdominal compression in infants

“…The compression jacket consisted of an inflatable plastic plate held over the chest and abdomen with a firm vinyl outer layer. RTC was performed with the arms outside the jacket to avoid possible splinting of the chest wall 15. The firm vinyl outer layer (Herculite 80, Vicar International, New Jersey, USA) was modified for the present study by inserting a 14 inch zipper (“Separating Sport Zipper”; Coats and Clark, Greenville, South Carolina, USA) so that the firm outer layer could be loosened during FRC measurement with minimal disturbance to the sleeping infant to avoid any possible limitation to chest wall excursions during tidal breathing.…”

Tidal forced expirations

“…2) Most studies are currently performed with the arms outside the jacket [15]. In cases in which the arms are wrapped inside the jacket, this should be explicitly reported.…”