Non-invasive ventilation and surfactant treatment as the primary mode of respiratory support in surfactant-deficient newborn piglets

Abstract

BackgroundNasal continuous positive airway pressure (NCPAP) and nasal intermittent positive pressure ventilation (NIPPV), forms of non-invasive ventilation (NIV) for respiratory support, are increasingly being chosen as the initial treatment for neonates with surfactant (SF) deficiency. Our objective was to compare NCPAP with NIPPV with or without SF administration as a primary mode of ventilation.MethodsTwenty-four newborn piglets with SF-deficient lung injury produced by repetitive bronchoalveolar lavages were randomly assigned to NCPAP or NIPPV, with or without SF administration (InSurE method). We evaluated pulmonary, systemic (hemodynamic and oxygen metabolism), and cerebral effects.ResultsSF-deficient piglets developed respiratory distress (F:1, pH<7.2, P>70 mm Hg, P<70 mm Hg, and C<0.5 ml/cmHO/kg). Gradual improvements in pulmonary status were observed in both NIV groups, with NIPPV achieving lower lung inflammation markers and injury scores. Both SF-treated groups obtained significantly better respiratory outcomes than groups not treated with SF before NIV. All NIV-treated groups showed low brain injury scores.ConclusionIn spontaneously breathing SF-deficient newborn piglets, NIPPV is a suitable NIV strategy. SF administration in combination with NCPAP or NIPPV improves pulmonary status providing extra protection against pulmonary injury. No injury to the developing brain was observed to be associated with these NIV strategies, with or without SF therapy.

Cerebral oxygenation associated with INSURE versus LISA procedures in surfactant‐deficient newborn piglet RDS model

“…Limitations of this study include the use of newborn piglets (2‐4 days old), which require SF washout lavage to induce lung injury. The SF washout lavage model has been frequently used in adult and juvenile animals to implement successful animal models of acute pulmonary failure in the context of RDS . The newborn piglet model was chosen because the brain maturation, lung volume, and birth weight resemble those of newborn infants.…”

“…As previously described, 2‐ to 4‐day‐old newborn piglets were sedated with an i.m. ketamine‐diazepam‐atropine injection and anesthetized with sevofluorane (2‐3%).…”

“…SF‐deficient lung injury was achieved by repetitive saline lavage (30 mL/kg; 37°C with F iO2 = 1) . After the first bronchoalveolar lavage (BAL), the PEEP was increased to 5 cmH 2 O, and PIP and RR were adjusted to a maximum of 25 cmH 2 O and 45 bpm, respectively.…”

“…Lung injury was scored by a pathologist blinded to treatment group using a semi‐quantitative scoring system. Pathological signs of lung injury (atelectasis, alveolar and interstitial inflammation, alveolar and interstitial hemorrhage, edema, and necrosis) were each scored on a 0‐4 point scale: 0 corresponding to no injury; 1, 2, and 3 to injury to 25%, 50%, and 75% of the field, respectively; and four to injury across the field . Moreover, all seven lung injury scores were summed in order to obtain a mean total lung injury score for each group, with a minimum value of 0 and maximum of 28, values higher than 12 corresponding to quite severe lung injury …”

“…Pathological features of brain injury (necrosis, inflammation, hemorrhage, edema and infarction) were each scored on a 0‐ to 3‐point scale: 0 corresponding to no injury; and 1, 2, and 3 to injury to mild, moderate, and severe injury across the field, respectively. The presence of more than five necrotic cells/field was considered to indicate neuronal necrosis (score range: 0‐20) …”