Mechanical Ventilation In Neonatal Respiratory Distress

Have you ever thought about how important breathing is? For newborns who have complications that occur either during pregnancy or at birth, breathing becomes a challenge that can affect their existence. This article introduces you to the complex world of neonatal respiratory distress.

Mechanical ventilation is a significant component in managing neonatal respiratory distress, offering essential respiratory assistance to newborns confronting breathing issues. By ensuring sufficient oxygenation and ventilation, mechanical ventilation aids in overcoming respiratory challenges and enhancing the likelihood of survival among newborns. Through precise adjustment of settings and modes, mechanical ventilation optimizes respiratory function and reduces the burden on the infant's lungs, contributing to their overall health and well-being.

Continue exploring to discover more details about neonatal respiratory distress and learn more about the significant role that mechanical ventilation plays in the management of this crucial condition. What are the associated risks and what other modern techniques are used today, I can find out by going through the article in front and looking for more details in the indicated references.

Neonatal respiratory distress

Respiratory distress is a leading cause of neonatal intensive care unit (ICU) admissions. Respiratory distress manifests with rapid breathing, nasal widening, chest retractions, and grunting, potentially leading to respiratory failure without prompt identification and treatment. A comprehensive evaluation, including medical history, clinical assessment, and diagnostic imaging, assists in diagnosing various conditions.¹

When newborns experience respiratory distress, healthcare providers assess various potential causes to determine the underlying condition. The most frequent culprits include transient tachypnea of the newborn, respiratory distress syndrome (also known as hyaline membrane disease), and meconium aspiration syndrome. However, less common but still significant factors may contribute to respiratory distress, such as delayed transition, infections like pneumonia or sepsis, and nonpulmonary issues like anaemia, congenital heart disease, or certain medications. Additionally, persistent pulmonary hypertension of the newborn and pneumothorax are less common yet noteworthy conditions that can lead to respiratory distress.²

Mechanical ventilation

Mechanical ventilation serves as a vital life-sustaining intervention. It involves the utilization of a mechanical ventilator, which acts as a device to assume the respiratory workload when an individual's natural breathing capacity is insufficient. A ventilator mode consists of a set of parameters that specify how a mechanical ventilator aids a patient's breathing. These parameters include factors like the timing, volume, and pressure of breath delivery, allowing for customization based on the patient's respiratory needs and condition. Mechanical ventilation operates based on two primary control variables: volume control (VC) and pressure control (PC). 

Mechanical ventilation serves to support respiratory function by aiding in oxygenation and the removal of carbon dioxide. During inspiration, muscles such as the diaphragm and intercostal muscles facilitate lung expansion to draw in air. Infants, characterized by their distinct anatomy, particularly rely on the diaphragm for breathing efforts, which can increase the likelihood of respiratory challenges. Ventilators assist by delivering airflow into the lungs to optimize respiratory function.³ 

In neonatal conventional ventilation, increasing oxygen uptake in the lungs involves raising the inspired oxygen level (FiO2), optimizing lung volume, and maximizing pulmonary blood flow. Carbon dioxide removal is achieved by adjusting tidal volume or ventilator rate.⁴

In mechanical ventilation, trigger and synchronization refer to the coordination between the patient's breathing efforts and the delivery of breaths by the ventilator. This ensures that the patient receives support when needed, enhancing the effectiveness of ventilation. Limiting inflation involves controlling the flow of gas during inspiration to avoid overinflation and potential lung injury. Cycling determines when inspiration ends and expiration begins, with settings based on either time or flow. These features are crucial for optimizing ventilation and supporting patients effectively during respiratory therapy.⁵

After deciding on invasive mechanical ventilation, it's important to reduce the risk of lung injury caused by ventilation. This involves selecting the right ventilation mode and settings. Whether to use conventional or high-frequency ventilation depends on the baby's condition and hospital protocols. Each baby's lung condition is unique, so factors like lung flexibility, airway resistance, and how hard it is for the baby to breathe should be considered.⁵ 

Causes of neonatal respiratory distress

The causes of respiratory distress in a newborn are diverse and multisystemic. Frequent causes encompass transient tachypnea of the newborn, neonatal pneumonia, respiratory distress syndrome (RDS), and meconium aspiration syndrome (MAS). 

Respiratory distress syndrome (RDS) also called Hyaline membrane disease (HMD), commonly affects premature infants and those born to mothers with diabetes during pregnancy. It arises due to inadequate alveolar surfactant levels, resulting in heightened surface tension within the alveoli and diminished lung capacities. This leads to radiographic findings of diffuse fine granular infiltrates. Infants with RDS typically display respiratory distress symptoms shortly after birth, characterized by rapid breathing, nasal flaring, grunting, and retractions of the chest wall.¹

Management of neonatal respiratory distress beyond ventilation

Treatment for neonatal respiratory distress involves oxygen therapy, surfactant administration, antibiotics for suspected infections, and, in critical cases, extracorporeal membrane oxygenation (ECMO). Pneumothorax may require needle decompression or chest tube drainage, with small pneumothoraces sometimes resolving without invasive measures. Collaboration between family physicians and neonatal intensivists is crucial, and transfer to a higher acuity hospital may be necessary if specialized care is unavailable.²

The management of neonatal respiratory distress involves addressing a spectrum of conditions, elucidated within distinct contexts outlined in the subsequent investigation:⁶

• Pulmonary hypertension: identified by elevated pressure in lung blood vessels, causing respiratory distress and cyanosis. Differentiating it from cyanotic heart disease is vital, often aided by a hyperoxia test
• Transient tachypnea of the newborn (TTN): prevented by avoiding elective cesarean sections before the onset of labour in infants younger than 39 weeks gestation. Administering antenatal glucocorticoids can reduce respiratory morbidity
• Perinatal pneumonia: antibiotic treatment, tailored to specific organisms like Group B streptococcus (GBS) in term infants, is crucial for managing this common newborn condition
• Respiratory distress syndrome (RDS): managed with supplemental oxygen, with severe cases requiring intubation and surfactant therapy. Guidelines for surfactant administration vary among institutions
• Meconium aspiration syndrome (MAS): supportive care includes supplemental oxygen and, in severe cases, CPAP or mechanical ventilation. Exogenous surfactant reduces the need for ECMO and lowers the risk of complications such as pneumothorax

A thorough medical history aids in diagnosing respiratory distress, with differential diagnoses varying by gestational age. Physical examination, including assessment for apnea, tachypnea, cyanosis, and cardiac and lung abnormalities, helps identify specific conditions. Severity assessment guides immediate interventions; mild distress may warrant observation, while severe distress requires resuscitation and diagnostic tests. Continuous reassessment, every two hours, allows for updates to treatment plans and parental education.²

Long-term outcomes and follow-up

Neurodevelopmental outcomes

Extended periods of mechanical ventilation correlate strongly with neurodevelopmental impairments in premature infants afflicted with severe respiratory distress syndrome (RDS). Mechanical ventilation, through the induction of positive intrathoracic pressure, may impede venous return, thereby reducing cardiac preload and compromising cardiac output, consequently resulting in fluctuating cerebral blood flow with potential long-term adverse repercussions. Furthermore, the regulation of carbon dioxide (CO2) exchange in mechanically ventilated infants typically involves manipulation by the healthcare team based on predetermined parameters.⁷

Respiratory outcomes

Preterm infants often develop bronchopulmonary dysplasia (BPD), which causes ongoing respiratory symptoms, lung function issues, and difficulty with exercise, even as they grow older.

Term infants who require MV may also experience complications like chronic lung disease and neurological problems such as seizures and abnormal brain findings. These issues can persist into adolescence and adulthood, impacting their respiratory health and overall well-being.

Innovative ventilation methods aim to improve respiratory outcomes by minimizing lung damage. Common practices include stabilizing newborns at risk of respiratory distress syndrome (RDS) using continuous positive airway pressure (CPAP) and avoiding intubation and mechanical ventilation (MV) when possible. Less invasive surfactant administration (LISA) is increasingly used to circumvent the need for intubation and MV. Early CPAP has been shown to reduce the risk of bronchopulmonary dysplasia (BPD) and respiratory issues. Nasal masks may offer greater benefits than prongs, and gradual pressure weaning during CPAP increases success rates. Nasal intermittent positive pressure ventilation (NIPPV) has demonstrated lower rates of treatment failure, MV, mortality, and BPD compared to CPAP or HHFNC. ⁸

Future directions in neonatal respiratory care

In the past, newborns with severe lung conditions faced high mortality rates until mechanical ventilation (MV) was introduced in the 1960s. MV, offered as intermittent positive pressure ventilation (IPPV) or intermittent negative pressure ventilation (INPV), became widespread in neonatal intensive care during the 1960s and 1970s. 

Despite MV being a standard treatment today, questions remain about its introduction in earlier care practices. A review of randomized controlled trials is essential to assess the balance of benefits and harms associated with MV and provide insights into its use in modern neonatal care.⁹

Summary

Neonatal respiratory distress poses a significant challenge in neonatal intensive care units (NICUs), often requiring mechanical ventilation (MV) as a crucial intervention. MV employs various modes tailored to address specific respiratory requirements, focusing on factors like timing, volume, and pressure of breath delivery. Despite its essential function, prolonged MV can lead to adverse neurodevelopmental consequences, especially in preterm infants with severe respiratory distress syndrome (RDS), due to potential alterations in hemodynamics and cerebral blood flow. Additionally, respiratory outcomes such as bronchopulmonary dysplasia (BPD) and chronic lung disease may endure into adolescence and adulthood, impacting long-term respiratory wellness. To address these challenges, innovative ventilation strategies aim to minimize lung damage and enhance outcomes, with early continuous positive airway pressure (CPAP) and less invasive surfactant administration (LISA) demonstrating promising results. Further investigation is warranted to optimize ventilation strategies and improve long-term respiratory outcomes for neonates.

FAQs

What are the indications for mechanical ventilation in newborns?

The reasons for using mechanical ventilation in newborns include respiratory failure, insufficient lung function, severe episodes of apnea and bradycardia, congenital heart defects, neurological disorders, and postoperative care.

What are the four criteria for mechanical ventilation initiation?

Four indicators are:

1. Respiratory rate exceeding 30 breaths per minute
2. Inability to sustain arterial oxygen saturation above 90% with an inspired oxygen fraction (FIO2) surpassing 0.60
3. pH below 7.25
4. Partial pressure of carbon dioxide (PaCO2) exceeding 50 mm Hg, unless it's a chronic and stable condition

What is the golden minute of neonatal resuscitation?

The concept of the "Golden Minute" in newborn resuscitation emphasizes the critical importance of initiating ventilation or chest compressions within one minute after delivery if needed.