Aeration strategy at birth influences the physiological response to surfactant in preterm lambs. Issue 6 (November 2019)

• Record Type: Journal Article
• Authors: Tingay, David Gerald; Togo, Andrea; Pereira-Fantini, Prue M; Miedema, Martijn; McCall, Karen E; Perkins, Elizabeth J; Thomson, Jessica; Dowse, Georgie; Sourial, Magdy; Dellacà, Raffaele L; Davis, Peter G; Dargaville, Peter Anderson
• Is Part Of: Archives of disease in childhood. Volume 104:Issue 6(2019)
• Page Start: F587
• Publication Date: 2019-11
• Subjects: animal research -- neonatology -- respiratory -- resuscitation; Infants -- Diseases -- Periodicals; Newborn infants -- Diseases -- Periodicals; Fetus -- Diseases -- Periodicals; 618.920105
• DOI: 10.1136/archdischild-2018-316240
• Languages: English
• ISSNs: 1359-2998

Abstract

Abstract : Background: The influence of pressure strategies to promote lung aeration at birth on the subsequent physiological response to exogenous surfactant therapy has not been investigated. Objectives: To compare the effect of sustained inflation (SI) and a dynamic positive end-expiratory pressure (PEEP) manoeuvre at birth on the subsequent physiological response to exogenous surfactant therapy in preterm lambs. Methods: Steroid-exposed preterm lambs (124–127 days' gestation; n=71) were randomly assigned from birth to either (1) positive-pressure ventilation (PPV) with no recruitment manoeuvre; (2) SI until stable aeration; or (3) 3 min dynamic stepwise PEEP strategy (maximum 14–20 cmH2 O; dynamic PEEP (DynPEEP)), followed by PPV for 60 min using a standardised protocol. Surfactant (200 mg/kg poractant alfa) was administered at 10 min. Dynamic compliance, gas exchange and regional ventilation and aeration characteristics (electrical impedance tomography) were measured throughout and compared between groups, and with a historical group (n=38) managed using the same strategies without surfactant. Results: Compliance increased after surfactant only in the DynPEEP group (p<0.0001, repeated measures analysis of variance), being 0.17 (0.10, 0.23) mL/kg/cmH2 O higher at 60 min than the SI group. An SI resulted in the least uniform aeration, and unlike the no-recruitment and DynPEEP groups, the distribution of aeration and tidal ventilation did not improve with surfactant. All groups had similar improvements in oxygenation post-surfactant compared with the corresponding groups not treated with surfactant. Conclusions: A DynPEEP strategy at birth may improve the response to early surfactant therapy, whereas rapid lung inflation with SI creates non-uniform aeration that appears to inhibit surfactant efficacy.