Nitric oxide in neonatal hypoxemic respiratory failure

No inhalation in combination with high frequency ventilation treatment in the treatment of neonatal severe respiratory failure

Objective:

To discuss over NO inhalation (iNO) in combination with high frequency ventilation treatment in relieving clinical symptoms and respiratory state of patients with neonatal severe respiratory failure.

Methods:

Ninety newborns with severe respiratory failure who received treatment in our hospital were selected for this study. They were divided into research group and control group according to visiting time. Patients in the control group were given conventional treatment in combination with high-frequency oscillatory ventilation, while patients in the research group were given iNO for treatment additionally besides the treatment the same as the control group. Changes of respiratory function indexes and arterial blood gas indexes of patients in the two groups were compared. Mechanical ventilation time, time of oxygen therapy and the length of hospital stay were recorded. Besides, postoperative outcome and the incidence of complications were analyzed.

Results:

After treatment, the level of PaO₂ of both groups significantly improved, and respiratory function indexes such as partial pressure of carbon dioxide in artery (PaCO₂), oxygenation index (OI), fraction of inspiration O₂ (FiO₂) and mean arterial pressure (MAP) decreased (P<0.05); the improvement of various indexes of the research group was more obvious than that of the control group (P<0.05). Mechanical ventilation time, oxygen therapy time and the length of hospital stay of the research group was much shorter than those of the control group. The incidence of complications in the two groups had no statistically significant difference (P>0.05), but the clinical outcome of the research group was better than that of the control group.

Conclusion:

NO inhalation in combination with high frequency ventilation for treating neonatal severe respiratory failure is effective in improving blood gas index and respiratory function, enhance cure rate, and reduce the incidence of complications and mortality; hence it is safe and effective and worth clinical promotion.

The fetal circulation, pathophysiology of hypoxemic respiratory failure and pulmonary hypertension in neonates, and the role of oxygen therapy

Neonatal hypoxemic respiratory failure (HRF), a deficiency of oxygenation associated with insufficient ventilation, can occur due to a variety of etiologies. HRF can result when pulmonary vascular resistance (PVR) fails to decrease at birth, leading to persistent pulmonary hypertension of newborn (PPHN), or as a result of various lung disorders including congenital abnormalities such as diaphragmatic hernia, and disorders of transition such as respiratory distress syndrome, transient tachypnea of newborn and perinatal asphyxia. PVR changes throughout fetal life, evident by the dynamic changes in pulmonary blood flow at different gestational ages. Pulmonary vascular transition at birth requires an interplay between multiple vasoactive mediators such as nitric oxide, which can be potentially inactivated by superoxide anions. Superoxide anions have a key role in the pathophysiology of HRF. Oxygen (O2) therapy, used in newborns long before our knowledge of the complex nature of HRF and PPHN, has continued to evolve. Over time has come the discovery that too much O2 can be toxic. Recommendations on the optimal inspired O2 levels to initiate resuscitation in term newborns have ranged from 100% (pre 1998) to the currently recommended use of room air (21%). Questions remain about the most effective levels, particularly in preterm and low birth weight newborns. Attaining the appropriate balance between hypoxemia and hyperoxemia, and targeting treatments to the pathophysiology of HRF in each individual newborn are critical factors in the development of improved therapies to optimize outcomes.