• Milena Tana, Graeme R Polglase, Francesco Cota, Chiara Tirone, Claudia Aurilia, Alessandra Lio, Cinzia Ricci, Costantino Romagnoli, and Giovanni Vento.
• 1Division of Neonatology, Policlinico A. Gemelli-Università Cattolica del Sacro Cuore, Rome, Italy. 2The Ritchie Centre, MIMR-PHI Institute of Medical Research, Clayton, VIC, Australia. 3Department of Obstetrics and Obstetrics and Gynaecology, Monash University, Clayton, VIC, Australia.
• Crit. Care Med. 2015 Aug 1;43(8):1685-91.

ObjectivesTo evaluate the changes in end-expiratory lung volume during an oxygenation-guided stepwise recruitment procedure in elective high-frequency ventilation. We hypothesized that high continuous distending pressure impedes pulmonary blood flow as evidenced by reduced lung volume measurements using respiratory inductive plethysmography. Changes in oxygenation, ventilation, and peripheral perfusion were evaluated as secondary outcomes.DesignA prospective, single center, observational, nonrandomized study.SettingThe study was conducted in a neonatal ICU in Italy.PatientsHigh-frequency ventilated preterm infants with respiratory distress syndrome.InterventionsDuring the recruitment procedure, end-expiratory lung volume measured by respiratory inductive plethysmography, oxygen saturation, perfusion index, regional cerebral and perirenal tissue oxygenation, heart rate, transcutaneous PCO2, and tidal volume were simultaneously recorded at each airway pressure step.Measurements And Main ResultsIn 12 preterm newborns (gestational age, 27.4 ± 0.2 wk; birth weight, 979 ± 198 g), high-frequency ventilation was initiated at a continuous distending pressure of 10 cm H2O and incrementally increased by 1-2 cm H2O every 2-5 minutes until FIO2 was less than or equal to 0.25. End-expiratory lung volume progressively increased during the initial recruitment, but decreased at the maximum airway pressure in nine patients, indicative of a reduction in pulmonary perfusion. At the end of recruitment, tidal volume was significantly higher (p = 0.002) and oxygenation was significantly improved (p = 0.002); however, mean perfusion index, postductal saturation, and mean renal tissue oxygenation values were significantly reduced (p < 0.05) compared with baseline. Mean cerebral tissue oxygenation and mean transcutaneous PCO2 values were reduced but failed to reach significance.ConclusionsHigh distending lung pressures increased oxygenation but decreased peripheral perfusion with no adverse cerebral side effects. Coupled with the reduction in respiratory inductive plethysmography-derived lung volume, high continuous distending pressure had adverse cardiopulmonary effects. Incorporation of lung volume and hemodynamic and oxygenation variables may guide optimum lung volume determination during high-frequency ventilation recruitment procedure while preventing adverse effects on the pulmonary circulation.

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