Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
We examined the effects of Pressure Support (PS) and Volume Guarantee (VG) modes of a prototype Drager Babylog ventilator on peak and mean airway pressures (PIP & Paw), inspiratory time (Tin) and tidal volume (TV) in 12 ventilated newborn infants (mean birth weight 1720±1280 g, gest. age 30.5±5.8 wk, age at time of study 25.8±31.5 days). In PS each breath is supported as in Assist/Control (A/C) and is terminated when inspiratory flow declines to 15% of baseline. In VG the device regulates PIP to achieve a preset TV. Data for 200-600 breaths were downloded directly from the ventilator pressure and volume monitoring module using proprietary software (Lufu 3, Drager, Lubeck) and analyzed using ABstat statistical software. Mean values and breath to breath variability (mean SD) were compared for 20 minute periods of A/C or synchronized intermittent mandatory ventilation (SIMV) followed by PS, PS with VG and back to baseline: A/C-PS-PS+VG-AC (n=6) or SIMV-PS-PS+VG-SIMV (n=6) using ANOVA for repeated measures. PS and PS+VG led to shorter Tin (reflecting breath termination) and thus to lower Paw, compared to A/C. Mean PIP was similar in PS+VG compared to the other modes but more variable, reflecting the servocontrol of PIP. TV did not differ between modes and tended to be less variable in PS+VG. PS and PS+VG led to higher and less variable PIP and Paw, compared to SIMV because each breath is supported. TV was similar in SIMV, PS and PS+VG but less variable with PS and PS+VG, again reflecting support of all breaths in PS as opposed to SIMV. The ventilator prototype functioned as intended, though breath to breath tidal volume variability was not completely eliminated. Data expressed as mean± SD. + p<0.01; * p<0.05 Table
