Oxygen Administration in Infants

• Joseph Priestley is credited with discovering oxygen in 1774, which Antoine Lavoisier later named.
• Arvo Ylppö recommended the intragastric administration of oxygen to infants, nearly 150 years after its discovery.
• In 1934, Dr. Julius Hess created the first inhaled oxygen delivery device for premature infants, called an "oxygen box".
• Oxygen administration aims to achieve adequate tissue oxygenation, using a system appropriate for the patient's size, gestational and postnatal age, and clinical condition.
• It is vital to provide oxygen therapy at safe levels, using the lowest possible fraction of inspired oxygen (Fio2) due to potential adverse reactions.

Indications

• A primary indication for oxygen therapy is to correct hypoxemia (low oxygen content in the blood).
• Untreated hypoxemia can progress to hypoxia (low tissue oxygen) and potentially anoxia (absent tissue oxygen), leading to anaerobic metabolism and lactic acidosis.
• Hypoxemia can result from decreased alveolar ventilation, decreased inspired oxygen, impaired ventilation-perfusion relationships, shunting, diffusion defects, or short red blood cell transit times.
• Oxygen delivery depends on hemoglobin concentration, its oxygen saturation, blood circulation rate, and oxygen unloading efficiency to tissues.
• Oxygen administration is appropriate if hypoxia is clinically suspected, but Pao2 or Spo2 is needed shortly after.
• In emergencies like respiratory distress or cardiopulmonary arrest, oxygen therapy is administered immediately, even without lab results.

Evidence of Hypoxemia

• In children, Pao2 below 80 mm Hg and Spo2 below 95% usually indicate hypoxemia.
• Treatment is initiated if Spo2 is less than 90% or Pao2 is less than 60 mm Hg.
• Due to fetal hemoglobin's higher affinity for oxygen, an Spo2 of 85% to 90% is normal for immediate postnatal Pao2 of 50 to 60 mm Hg.
• In neonates, hypoxemia is indicated by Pao2 less than 50 mm Hg and Spo2 less than 88%, necessitating oxygen therapy initiation.
• Pao2 and Spo2 are key clinical indicators for initiating, monitoring, adjusting, and terminating oxygen administration.

Clinical Signs and Symptoms

• Early signs of hypoxia include tachycardia and tachypnea.
• Worsening hypoxia can lead to decreased ventilation, apnea, and bradycardia.
• Other signs include grunting, nasal flaring, retractions, paradoxical breathing, cyanosis, irritability, and restlessness.
• Prolonged hypoxia may result in decreased consciousness, lethargy, and flaccidity.
• Cyanosis is an unreliable indicator of tissue hypoxia.

Complications

• Two main categories of complications exist: adverse physiologic effects and equipment-related complications.
• Consequences of hypoxia outweigh the potential risks of oxygen, however risks are still present when administered.
• In lung disorders like cystic fibrosis and bronchopulmonary dysplasia, the normal ventilation response is blunted due to carbon dioxide retention.
• Excessive supplemental oxygen decreases respiratory drive, causing hypoventilation and respiratory acidosis, which may lead to respiratory arrest.
• In lung patients, use low Fio2 and adjust based on Pao2 or Spo2 monitoring.
• Excessive oxygen can cause retinopathy of prematurity (ROP).
• Avoid high levels of oxygen can suppress the growth of factors resulting in leading to retinal and cerebral constriction in premature neonates, resulting in ischemia.
• Current practice is to maintain Spo2 levels at 88% to 95% and a PaO2 value of 50 to 80 mm Hg in premature neonates.
• Oxygen needs to be vigilantly managed without causing death and disability
• High concentrations of oxygen have been linked to atelectasis, pulmonary vasodilation, and pulmonary fibrosis.
• High oxygen = increased alveolar oxygen = decreased alveolar nitrogen
• The blood rapidly absorbs the oxygen, gas volume decreases, and atelectasis develops.
• High Fio2 levels may also cause pulmonary vasodilation, leading to increased intrapulmonary shunting and worsening arterial oxygen delivery.
• Pulmonary fibrosis has been reported in patients with Paraquat poisoning and those receiving bleomycin.

Oxygen Administration

• Many devices used to deliver oxygen to neonatal and pediatric patients are smaller versions of adult devices.
• Devices classified as variable-performance (low-flow) or fixed-performance (high-flow) systems.
• Variable-performance systems don't meet inspiratory demand, Fdo2 varies with ventilation rate and depth and gas flow rate.
• Variable-performance systems comprise low-flow nasal cannulas, nasopharyngeal catheters, tracheostomy oxygen adapters, simple oxygen masks, partial-rebreathing masks, and nonrebreathing masks.
• Fixed-performance systems meet or exceed inspiratory demand, giving accurate, ventilation-pattern independent Fdo2.
• This category contains high-flow nasal cannulas (HFNCs), air-entrainment masks, air-entrainment nebulizer systems, and oxygen blender systems.
• The last category includes enclosure systems for controlling oxygen concentration, temperature, and humidity.

Nasal Cannula

• Nasal cannulas have flexible small-bore tubing ending in two soft prongs (0.25 to 1 cm long).
• Oxygen flows through the cannula into the nasopharynx, acting as an anatomic reservoir.
• Cannulas provide low oxygen concentrations (24% to 45%), with Fio2 varying with inspiratory flow.
• Allows caregivers to feed and provide patient care, provides increased patient mobility.
• Cannulas are contraindicated in patients with nasal obstructions
• Select size to ensure nares aren't occluded, the lightweight tubing is wrapped around the ears and held under the chin
• In small or active infants, secure to face and position tubing for securing behind the head
• Application includes a flow meter and bubble humidifier.