Background: It would be advantageous for the treatment of neonatal respiratory distress syndrome if effective amounts of surfactant could be delivered by nebulization. Objective: To investigate lung deposition and distribution of nebulized porcine surfactant using an investigational eFlow® neonatal nebulizer. Methods: While lying on one side, 1-day-old piglets inhaled 200 mg·kg^-1 of nebulized surfactant via mask, nasal prongs, or tracheal tube. The surfactant was diluted with normal saline to 40 mg·ml^-1 and labeled with ^99mtechnetium-labelled nanocolloid. Undiluted surfactant (80 mg·ml^-1) was instilled tracheally in a fourth group. Each group had 8 animals. Lung deposition was measured by gamma scintigraphy, and deposition values were presented as a percentage of the nebulized or instilled dose. Results: The median lung deposition of inhaled surfactant was 5% (range 3-16) via mask, 14% (2-40) via prongs, and 45% (25-56) via tracheal tube (p < 0.05). It was 88% (71-96) with instillation. In all groups, the surfactant preferentially went to the dependent lung. Deposition ratios (upper lung/both lungs) were 0.32 (0.13-0.58), 0.15 (0.05-0.58), 0.16 (0.11-0.23), and 0.08 (0.03-0.46). Conclusions: Using this nebulizer, the lung depositions of porcine surfactant were 45% via endotracheal tube and 14% via nasal-continuous positive airway pressure (prongs). These figures might be physiologically relevant, but still have to be confirmed in efficacy studies.

Background Nasal continuous positive airway pressure support (nCPAP) is the standard of care for prematurely born infants at risk of neonatal respiratory distress syndrome (nRDS). However, nasal intermittent positive pressure ventilation (NIPPV) may be an alternative to nCPAP in babies requiring surfactant, and in conjunction with surfactant nebulization, it could theoretically reduce the need for invasive mechanical ventilation. We compared lung deposition of nebulized poractant in newborn piglets supported by nCPAP or NIPPV. Methods Twenty‐five sedated newborn piglets (1.2‐2.2 kg) received either nCPAP (3 cmH2O, n = 12) or NIPPV (3 cmH2O positive end expiratory pressure+3 cmH2O inspiratory pressure, n = 13) via custom‐made nasal prongs (FiO2 0.4, Servo‐i ventilator). Piglets received 200 mg kg−1 of technetium‐99m‐surfactant mixture continuously nebulized with a customized eFlow‐Neos investigational vibrating‐membrane nebulizer system. Blood gases were taken immediately before, during, and after nebulization. The deposition was estimated by gamma scintigraphy. Results Mean surfactant deposition in the lungs was 15.9 ± 11.9% [8.3, 23.5] (mean ± SD [95% CI]) in the nCPAP group and 21.6 ± 10% [15.6, 27.6] in the NIPPV group (P = .20). Respiratory rates were similar in both groups. Minute volume was 489 ± 203 [360, 617] in the nCPAP group and 780 ± 239 [636, 924] mL kg−1 min−1 in the NIPPV group (P = .009). Blood gases were comparable in both groups. Conclusion Irrespective of the noninvasive ventilatory support mode used, relatively high lung deposition rates of surfactant were achieved with nebulization. The amounts of deposited surfactant might suffice to elicit a pulmonary function improvement in the context of nRDS.

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Early adrenaline administration does not improve circulatory recovery during resuscitation from severe asphyxia in newborn piglets.Linnér, Rikard; Werner, Olof; Perez de Sá, Valéria; Cunha Goncalves, Doris General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.• Users may download and print one copy of any publication from the public portal for the purpose of private study or research.• You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal Take down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. (28) AbstractAim of the study: To investigate the effects of early intravenous adrenaline administration on circulatory recovery, cerebral reoxygenation, and plasma catecholamine concentrations, after severe asphyxia-induced bradycardia and hypotension.Methods: One-day-old piglets were left in apnoea until heart rate and mean arterial pressure were less than 50 min -1 and 25 mmHg, respectively. They randomly received adrenaline, 10 µg kg -1 (n=16) or placebo (n=15) and were resuscitated with air ventilation and, when needed, closed-chest cardiac massage (CCCM). Eight not asphyxiated animals served as time controls.Results: CCCM was required in 13 piglets given adrenaline and in 13 given placebo. (ns). In the time controls, the concentrations were 0.4 (0.2-0.6) nmol l -1 of adrenaline and 1.8 (1.3-2.4) nmol l -1 of noradrenaline. (28)Conclusion: The high endogenous catecholamine levels, especially those of noradrenaline, may explain why early administered adrenaline did not significantly improve resuscitation outcome.

BACKGROUND: Earlier attempts to deliver effective lung doses of surfactant by aerosolization were unsuccessful, mostly because of technical shortcomings. We aimed at quantifying the lung deposition of poractant alfa with a new supraglottic delivery system for surfactant atomization in an experimental neonatal model. METHODS: The method involved six sedated 1-day-old piglets lying in the lateral decubitus, spontaneously breathing on nasalmask continuous positive airway pressure (nCPAP). A pharyngeal cannula housing a multi-channel air-blasting atomization catheter was placed through the mouth with its tip above the glottis entrance. In all, 200 mg kg −1 of a 99m Tc-surfactant mixture was atomized through the catheter synchronously with inspiration. Six intubated control piglets received an equal amount of intratracheally instilled 99m Tc-surfactant mixture. The percentage of the 99m Tc-surfactant mixture deposited in the lungs was estimated by scintigraphy. RESULTS: Median (range) deposition in the lungs was 40% (24-68%) after atomization and 87% (55-95%) after instillation (p < 0.001). Overall, almost 80% of the deposited surfactant was in the dependent lung. Effective atomization time (atomizer on) was 28 (17-52) min, yielding an output rate of 0.1-0.2 mL min −1 . CONCLUSIONS: Without endotracheal intubation, in spontaneously breathing newborn piglets, this new supraglottic atomizer delivery system attained a median lung deposition of 40% of the nominal dose of surfactant.