G. Bernstein et al., RESPONSE-TIME AND RELIABILITY OF 3 NEONATAL PATIENT-TRIGGERED VENTILATORS, The American review of respiratory disease, 148(2), 1993, pp. 358-364
We studied the response time (RT) and reliability of three neonatal pa
tient-triggered ventilator (PTV) systems: the Draeger Babylog(R) 8000,
the Bear Cub(R) enhancement module (CEM), and the Infrasonics Star Sy
nc(R). In 10 adult rabbits, airway flow and pressure recordings showed
the RT of the Star Sync to be shorter than that of the Bear CEM (53 /- 13 versus 65 +/- 15 ms, p < 0.05), and both were shorter than that
of the Babylog (95 +/- 24 ms, p < 0.01) by ANOVA. The RT of the Bear C
EM and the Babylog increased significantly at decreased trigger sensit
ivity settings. All ventilators triggered successfully on assist-contr
ol (A/C). However, the Babylog had a higher rate of asynchrony on SIMV
(30 +/- 25%) than the Bear CEM (1.1 +/- 0.3%) and the Star Sync (1.2
+/- 0.4%), p < 0.01. In 10 infants with respiratory failure, recording
s of airway flow and pressure were made at ventilator inspiratory time
(Tl settings of 0.3, 0.4, and 0.5 s on assist-control and on SIMV at
rates of 15,30,45, and 60 breaths/min. The Star Sync and Bear CEM trig
gered successfully on A/C (100%) and had low rates of asynchrony on SI
MV (1 to 3%). The Babylog had a lower success rate on A/C (70 +/- 12%)
and a higher rate of asynchrony on SIMV (29 +/- 30%) than the other t
wo ventilators; p < 0.01. The lower reliability of the Babylog was due
to its variable refractory period (0.2 to 0.5 s, to equal the set Tl)
. At Tl greater-than-or-equal-to 0.4 s, this caused missed ventilator
triggering on alternate spontaneous breaths, which resulted in phase l
ocking in asynchrony on SIMV at rates of 45 and 60 breaths/min. The St
ar Sync and Bear CEM had shorter RT than previously reported neonatal
PTV systems, and the Babylog had a unique but potentially correctable
design feature that adversely affected its reliability.