BackgroundThe influence of pressure strategies to promote lung aeration at birth on the subsequent physiological response to exogenous surfactant therapy has not been investigated.ObjectivesTo 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.MethodsSteroid-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 cmH2O; 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.ResultsCompliance 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/cmH2O 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.ConclusionsA 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.
ObjectiveSkin-to-skin care (SSC) has proven psychological benefits; however, the physiological effects are less clearly defined. Regional ventilation patterns during SSC have not previously been reported. This study aimed to compare regional ventilation indices and other cardiorespiratory parameters during prone SSC with supine and prone position cot-nursing.DesignProspective observational study.SettingSingle quaternary neonatal intensive care unit in Australia.Patients20 infants spontaneously breathing (n=17) or on non-invasive ventilation (n=3), with mean (SD) gestational age at birth of 33 (5) weeks.InterventionsThirty-minute episodes of care in each position: supine cot care, prone SSC and prone cot care preceding a 10 min period of continuous electrical impedance tomography measurements of regional ventilation.Main outcome measuresIn each position, ventral–dorsal and right–left centre of ventilation (CoV), percentage of whole lung ventilation by region and percentage of apparent unventilated lung regions were determined. Heart and respiratory rates, oxygen saturation and axillary temperature were also measured.ResultsHeart and respiratory rates, oxygen saturation, temperature and right-left lung ventilation did not differ between the three positions (mixed-effects model). Ventilation generally favoured the dorsal lung, but the mean (95% CI) ventrodorsal CoV was −2.0 (−0.4 to –3.6)% more dorsal during SSC compared with prone. Supine position resulted in 5.0 (1.5 to 5.3)% and 4.5 (3.9 to 5.1)% less apparently unventilated lung regions compared with SSC and prone, respectively.ConclusionsIn clinically stable infants, SSC generates a distinct regional ventilation pattern that is independent of prone position and results in greater distribution of ventilation towards the dorsal lung.
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