title: Randomized controlled trial of volume-targeted synchronized ventilation and conventional intermittent mandatory ventilation following initial exogenous surfactant therapy.
abstract: We set out to evaluate the impact of volume-targeted synchronized ventilation and conventional intermittent mandatory ventilation (IMV) on the early physiologic response to surfactant replacement therapy in neonates with respiratory distress syndrome (RDS). We hypothesized that volume-targeted, patient-triggered synchronized ventilation would stabilize minute ventilation at a lower respiratory rate than that seen during volume-targeted IMV, and that synchronization would improve oxygenation and decrease variation in measured tidal volume (V(t)). This was a prospective, randomized study of 30 hospitalized neonates with RDS. Infants were randomly assigned to volume-targeted ventilation using IMV (n = 10), synchronized IMV (SIMV; n = 10), or assist/control ventilation (A/C; n = 10) after meeting eligibility requirements and before initial surfactant treatment. Following measurements of arterial blood gases and cardiovascular and respiratory parameters, infants received surfactant. Infants were studied for 6 hr following surfactant treatment. Infants assigned to each mode of ventilation had similar birth weight, gestational age, and Apgar scores at birth, and similar oxygenation indices at randomization. Three patients were eliminated from final data analysis because of exclusionary conditions unknown at randomization. Oxygenation improved significantly following surfactant therapy in all groups by 1 hr after surfactant treatment (P < 0.05). No further improvements occurred with time. Total respiratory rate was lowest (P < 0.05) and variation in tidal volume (V(t)) was least in the A/C group (P < 0. 05). Minute ventilation (V(')(E)), delivered airway pressures, respiratory system mechanics, and hemodynamic parameters were similar in all groups. We conclude that volume-targeted A/C ventilation resulted in more consistent tidal volumes at lower total respiratory rates than IMV or SIMV. Oxygenation and lung mechanics were not altered by synchronization, possibly due to the volume-targeting strategy. Of the modes studied, A/C, a fully-synchronized mode, may be the most efficient method of mechanical ventilator support in neonates receiving surfactant for treatment of RDS.
authors.affiliation: Infant Pulmonary Research Center, Children's Hospital-St. Paul and the Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA.
authors.forename: J D
authors.initials: JD
authors.lastname: Mrozek
authors.forename: E M
authors.initials: EM
authors.lastname: Bendel-Stenzel
authors.forename: P A
authors.initials: PA
authors.lastname: Meyers
authors.forename: D R
authors.initials: DR
authors.lastname: Bing
authors.forename: J E
authors.initials: JE
authors.lastname: Connett
authors.forename: M C
authors.initials: MC
authors.lastname: Mammel
mesh_terms: D001784:Blood Gas Analysis; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007322:Instillation, Drug; D007385:Intermittent Positive-Pressure Ventilation; D008297:Male; D010100:Oxygen / Q000378:metabolism; D011446:Prospective Studies; D011659:Pulmonary Gas Exchange; D011663:Pulmonary Surfactants / Q000008:administration & dosage / Q000627:therapeutic use*; D012127:Respiratory Distress Syndrome, Newborn / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D015656:Respiratory Mechanics; D013990:Tidal Volume; D016896:Treatment Outcome
chemical_list: D011663:Pulmonary Surfactants; D010100:Oxygen