CHOOSING A NEGATIVE-PRESSURE VENTILATION PUMP - ARE THERE ANY IMPORTANT DIFFERENCES

Citation
Ie. Smith et al., CHOOSING A NEGATIVE-PRESSURE VENTILATION PUMP - ARE THERE ANY IMPORTANT DIFFERENCES, The European respiratory journal, 8(10), 1995, pp. 1792-1795
Citations number
12
Categorie Soggetti
Respiratory System
ISSN journal
09031936
Volume
8
Issue
10
Year of publication
1995
Pages
1792 - 1795
Database
ISI
SICI code
0903-1936(1995)8:10<1792:CANVP->2.0.ZU;2-S
Abstract
Five negative pressure ventilator pumps were assessed to determine whe ther there were any differences in performance which were likely to be of clinical importance. The pumps tested were the NEV-100 (Lifecare I nc), the Negavent Respirator DA-1 (Dima Italia), the Thompson Maxivent (Puritan Bennett), the CCP-001 and Newmarket pumps (Si-Pian Electroni cs Research Ltd). A patient model was employed to investigate the rela tionship between the pressure waveform of each pump and the tidal volu me generated, the stability of performance on a continuous 8 h test, a nd the response to a change in leak. On the continuous tests, the stab ility was better than +/-1% for the inspiratory/expiratory (I:E) ratio and rate, and better than +/-10%, for the peak negative pressure for all of the pumps. The Negavent and NEV-100 pumps generated a square wa ve of pressure and for the same peak negative pressure produced a tida l volume up to 30% greater than the CCP-001 and the Newmarket pumps, w hich produced a half sine wave. The Maxivent produced an intermediate waveform, with a plateau at peak negative pressure but a curved decay back to atmospheric pressure. It is argued that if the pressure of the pumps producing a half sine wave is made more negative to compensate and produce an equivalent tidal volume, they are more likely to induce upper airway obstruction. The leak compensation of the NEV-100 and Ne gavent pumps was nearly complete but took several breaths to develop, the CCP-001 and Newmarket pumps had a very rapid compensation but this was less complete, whilst the Maxivent has no mechanism for leak comp ensation. From these results, it seems that in patients liable to uppe r airway obstruction the NEV-100 and Negavent pumps would be advantage ous, whilst when rapidly changing leaks impair the efficiency of negat ive pressure ventilation the CCP-001 and Newmarket pumps would be pref erable. The Maxivent pump seems to offer no advantages.