Neonatal lung injury Antonio Souto [email protected]Médico coordenador Unidade de Medicina Intensiva Pediátrica Unidade de Medicina Intensiva Neonatal Hospital Padre Albino Professor de Pediatria nível II Faculdades Integradas Padre Albino Catanduva / SP
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•Specific decisions about respiratory care practice during the first day of life influence the outcome of a very low birth weight infant
•Failure to decrease ventilatory support may increase the risk of developing chronic lung disease, intraventricularhemorrhage, and retinopathy of prematurity
Several studies show that optimizing lung recruitment reduces lung inflammation,
improves surfactant function, and decreases lung injury.
• Lung immaturity, alveolar atelectasis, and edema decrease the gas volume
• Only a small portion of the lung may be recruited and available for ventilation
TV of 10 TV of 10 TV of 10 TV of 10 mLmLmLmL/kg delivered may be equivalent to /kg delivered may be equivalent to /kg delivered may be equivalent to /kg delivered may be equivalent to
20 to 30 20 to 30 20 to 30 20 to 30 mLmLmLmL/kg and will result in volutrauma/kg and will result in volutrauma/kg and will result in volutrauma/kg and will result in volutrauma
Prolonged Prolonged Prolonged Prolonged hyperoxiahyperoxiahyperoxiahyperoxia initiates a lung injury initiates a lung injury initiates a lung injury initiates a lung injury sequence that can lead to inflammation, diffuse sequence that can lead to inflammation, diffuse sequence that can lead to inflammation, diffuse sequence that can lead to inflammation, diffuse
alveolar damage, progressive pulmonary alveolar damage, progressive pulmonary alveolar damage, progressive pulmonary alveolar damage, progressive pulmonary dysfunction, and death.dysfunction, and death.dysfunction, and death.dysfunction, and death.
Cytokines and biotrauma in ventilator-induced lunginjury
Pulmonary and systemic inflammatory responses to acute lung injury
Significant potential exists for the lungs to Significant potential exists for the lungs to Significant potential exists for the lungs to Significant potential exists for the lungs to interact with, and contribute to, the interact with, and contribute to, the interact with, and contribute to, the interact with, and contribute to, the
circulating pool of inflammatory cells.circulating pool of inflammatory cells.circulating pool of inflammatory cells.circulating pool of inflammatory cells.
•Increased expression of tumor necrosis factor–[alpha] by alveolar macrophages
Manifestations of lung injury were almost completely Manifestations of lung injury were almost completely Manifestations of lung injury were almost completely Manifestations of lung injury were almost completely abrogated in granulocyteabrogated in granulocyteabrogated in granulocyteabrogated in granulocyte----depleted rabbitsdepleted rabbitsdepleted rabbitsdepleted rabbits
Injure the alveolarInjure the alveolarInjure the alveolarInjure the alveolar----capillary barriercapillary barriercapillary barriercapillary barrier
•Efflux of inflammatory mediators into the general circulation.
•A systemic inflammatory response can also be promoted by translocation of bacteria and endotoxin from the air spaces into the circulation.
•Findings in recent human studies in adults show that ventilatory strategy has an impact on pulmonary and systemic cytokines and that these changes are associated with multisystem organ failure.
Changes in lung volume are dependent on regional lung compliance
Optimal is the tidal volume that creates a Optimal is the tidal volume that creates a Optimal is the tidal volume that creates a Optimal is the tidal volume that creates a homogeneous delivery of each breath to the homogeneous delivery of each breath to the homogeneous delivery of each breath to the homogeneous delivery of each breath to the open lung units without creating volutraumaopen lung units without creating volutraumaopen lung units without creating volutraumaopen lung units without creating volutrauma
•The most important volume to optimize is FRC
•An open lung allows more uniform distribution of each tidal volume breath and reduces the potential for volutrauma
What can we do clinically to prevent What can we do clinically to prevent What can we do clinically to prevent What can we do clinically to prevent atelectraumaatelectraumaatelectraumaatelectrauma????
•Comparing nurseries that more commonly use assisted ventilation with nurseries that use CPAP in the initial treatment of very low birth weight infants
•most of the increased risk of chronic lung disease most of the increased risk of chronic lung disease most of the increased risk of chronic lung disease most of the increased risk of chronic lung disease was explained was explained was explained was explained ““““simply by the initiation of simply by the initiation of simply by the initiation of simply by the initiation of mechanical ventilation.mechanical ventilation.mechanical ventilation.mechanical ventilation.””””•Practice differences influence outcome
When to provide mechanical ventilation?When to provide mechanical ventilation?When to provide mechanical ventilation?When to provide mechanical ventilation?
A problem is the potential risks of waiting to A problem is the potential risks of waiting to A problem is the potential risks of waiting to A problem is the potential risks of waiting to interveneinterveneinterveneintervene
•delaying the “appropriate” use of surfactant
Well-designed trials in which CPAP is compared with early intubation are needed
Thus, a Thus, a Thus, a Thus, a ““““normalnormalnormalnormal”””” PaCOPaCOPaCOPaCO2222 value should value should value should value should remain the target until more data from remain the target until more data from remain the target until more data from remain the target until more data from
human studies are availablehuman studies are availablehuman studies are availablehuman studies are available
Preventing oxygenPreventing oxygenPreventing oxygenPreventing oxygen----induced lung injuryinduced lung injuryinduced lung injuryinduced lung injuryTin W, Milligan DW, Tin W, Milligan DW, Tin W, Milligan DW, Tin W, Milligan DW, PennefatherPennefatherPennefatherPennefather P, Hey E. Pulse P, Hey E. Pulse P, Hey E. Pulse P, Hey E. Pulse oximetryoximetryoximetryoximetry, severe , severe , severe , severe retinopathy, and outcome at one year in babies of less than 28 wretinopathy, and outcome at one year in babies of less than 28 wretinopathy, and outcome at one year in babies of less than 28 wretinopathy, and outcome at one year in babies of less than 28 weeks eeks eeks eeks gestation. Arch gestation. Arch gestation. Arch gestation. Arch DisDisDisDis Child Fetal Neonatal Ed 2001; 84:F106Child Fetal Neonatal Ed 2001; 84:F106Child Fetal Neonatal Ed 2001; 84:F106Child Fetal Neonatal Ed 2001; 84:F106----F110F110F110F110
•Oxygen for 8 weeks
•saturation of 88% to 98% X saturation of 70% to 90%
•saturation of 88% to 98%saturation of 88% to 98%saturation of 88% to 98%saturation of 88% to 98%
your mind If these strategic principles If these strategic principles If these strategic principles If these strategic principles are followed, we can reduce are followed, we can reduce are followed, we can reduce are followed, we can reduce the pulmonary and systemic the pulmonary and systemic the pulmonary and systemic the pulmonary and systemic
inflammatory changes inflammatory changes inflammatory changes inflammatory changes associated with ventilatorassociated with ventilatorassociated with ventilatorassociated with ventilator----
induced lung injury and induced lung injury and induced lung injury and induced lung injury and hopefully promote better hopefully promote better hopefully promote better hopefully promote better