Management of a premature infant’s first hour of life in the delivery room can result in short- and long-term injury, developmental delay, and death.1 Delivery room practices are contributing factors to long-term development and may influence the development of chronic lung disease.2 As few as six manual breaths via bag and mask can cause lung injury.3 Infants diagnosed with chronic lung disease have a high risk of mortality in the first year of life and respiratory disorders such as respiratory distress, hypoxia, atelectasis, pulmonary hemorrhage, and interstitial emphysema account for 12.6 percent of total deaths in the neonatal period.2,4
Accordingly, the processes and interventions associated with the neonate’s respiratory adaptation to extrauterine life present the opportunity for Respiratory Therapists to significantly impact care.
Transition to extrauterine life is one of the most intense periods of human adaption. Circulation, fluid balance, gas exchange, sensory input, and metabolic independence change within seconds. Events surrounding premature birth are often chaotic, stressful, intense, susceptible to error, and wrought with miscommunication. Accordingly, some have postulated the first hour of neonatal life parallels concepts upon which the Golden Hour of Trauma is based.1
“The Golden Hour” of trauma traditionally refers to the hour after a traumatic event when the chance for survival is highest.5 In essence, the sooner a patient receives definitive care by a trained team, the better their chance of survival. To optimize care standardized processes and practices revolve around notification, team response, preparation, resuscitation, stabilization and procedures, and transfer.6 In infant care the team may include a Physician, Neonatal Practitioner, Nurse, Respiratory Therapist, and Parents and Family. Components of Golden Hour care focus on circulation and perfusion, fluids and electrolytes, metabolic independence, nutrition, management of respiratory status, thermoregulation, and neurologic considerations.6 Here we will focus on aspects related to respiratory intervention and stabilization.
An overarching goal of neonatal respiratory resuscitation is to use the least amount of intervention necessary to support normal gas exchange while minimizing lung injury.7 The more specific goals of neonatal respiratory support are to maintain adequate oxygenation through establishing and maintaining functional residual capacity, achieving adequate pulmonary blood flow, improving lung compliance and decreasing work of breathing, treating apnea, and providing assisted ventilation.6 These specific goals can be grouped into maintaining adequate oxygenation, maintaining adequate minute ventilation, and preventing iatrogenic complications.
In order to maintain adequate oxygenation and minute ventilation we must establish and maintain functional residual capacity, or recruit and stabilize alveoli. Three essential therapies promote lung recruitment and stabilization: Manual ventilation, CPAP, and surfactant delivery8. Crying recruits lung volume and in mature lungs the lung structure and surfactant stabilize alveoli. Preterm infants may need assistance in the form of gentle stimulation to induce crying or through manual ventilation to overcome immature lung structure and a lack of endogenous surfactant.8 Manual ventilation can be achieved through self-inflating bags, flow-inflating bags, and T-piece resuscitators.8 T-piece resuscitators have been shown to provide consistent peak inspiratory pressures (PIP) and positive end-expiratory pressure (PEEP) regardless of operator(9). Initial critical opening pressures during ambu or Neopuff ventilation should be individualized with initial breaths often requiring higher inflation pressures and subsequent breaths often requiring less pressure. Term infant inflation pressure may reach 30 cmH20 while premature infants may need 20-25 cmH20 of initial pressure10. Efforts should induce a gentle chest rise and produce an increase in heart rate, rising oxygen saturation, and bilateral breath sounds.
In addition to crying and manual ventilation, CPAP can assist in recruiting and stabilizing alveoli. CPAP stabilizes lung inflation at end-exhalation, allowing the next breath to further recruit the lung(10). Early application of CPAP can also reduce lung damage by preventing shear forces produced when recruited alveoli collapse during exhalation and then are forced upon at the next inhalation3. CPAP levels should be individualized, but reach at least 4-5 cmH206. Like manual ventilation, appropriate CPAP levels should produce a stabilization of heart rate and oxygen saturation.
Surfactant delivery is an additional method to recruit and maintain alveoli. Although many hospitals have their own protocols concerning surfactant delivery, some basic concepts apply. Surfactant is most frequently indicated in the preterm infant in the presence of Respiratory Distress Syndrome (RDS). RDS is defined in the preterm infant by the presence of acute respiratory distress with disturbance in in gas exchange. The chest x-ray contains a ground glass appearance and may have air bronchograms and decreased lung volume(11). Surfactant dysfunction can occur in preterm infants, meconium aspiration, pneumonia, and pulmonary hemorrhage11. Recommendations for administering exogenous surfactant delivery include in intubated infants with RDS, meconium aspiration requiring >50% oxygen, infants with pneumonia and an oxygenation index > 15, and pulmonary hemorrhage leading to clinical decline11. The benefits of surfactant administration must be weighed against the risks of therapy, including bradycardia, tachypnea, hypoxemia, hyperventilation, baro- or volutrauma, and pulmonary hemorrhage(11).
Now that we’ve introduced you to the very basis of respiratory considerations during the Neonatal Golden Hour, our next post we’ll cover specific tips for respiratory resuscitation during the Golden Hour.