Objective: To compare pressure support ventilation combined with volume guarantee (PSV-VG) to synchronized intermittent mandatory ventilation (SIMV) regarding safety, course of blood gases, and infant-ventilator interaction in premature infants.
Design: Prospective, two-treatment, crossover pilot study.
Setting: Tertiary care neonatal unit.
Patients: Twenty-five ventilated premature infants: median (range) gestational age 26.1 wks (23.1-35.7), birth weight 765 g (450-3170), age at study 5 days (2-27), in their weaning phase.
Interventions: Infants were studied for three 30-min periods, starting from SIMV, followed by PSV-VG, and back again to SIMV. After concluding the last period, all infants were switched back to PSV-VG. On the next day, infants were studied in the opposite direction. During each period, vital parameters, ventilation parameters, degree of physical activity, duration of rhythmic breathing, and the number of vital signs monitor alarms were recorded.
Measurements and main results: Nineteen infants (84%) could be successfully ventilated with PSV-VG till the next day. PSV-VG achieved a similar oxygenation level as SIMV but with significantly lower ventilation pressures. Comparable ventilation was achieved, but infants with strong respiratory drive were more liable to hyperventilation episodes during PSV-VG. Although infants breathed more rhythmically during PSV-VG, suggesting better infant-ventilator synchrony, the infants' behavioral state and the fluctuations in blood gases did not differ.
Conclusions: The potentials of PSV-VG to improve infant-ventilator synchrony and to decrease pressure needed to ventilate premature lungs are promising, even though the changes were small. However, its benefits during acute illness and on the final outcome remain to be proven.