Apnea of Prematurity: Pathogenesis, Signs & Symptoms, and Complications Physiologic immaturity from birth at < 37 weeks gestation Authors: Akaya Blair Reviewers: Dasha Mori Michelle J. Chen Danielle Nelson* * MD at time of publication ↓ Synaptic connection & poor myelination Fetal brain areas responsible for breathing are poorly developed Immature neurologic respiratory function Immature mechanical respiratory function Poor hypopharyngeal muscle tone (soft upper airway helps with size and compliance of airway) Nasal obstruction (e.g. anatomic and/or iatrogenic [suctioning, NG tubes]) Neonate is reliant on nose breathing Airway is unable to remain open (patent) Laryngeal/tracheal abnormalities (e.g. tracheomalacia, laryngeal edema, tracheal stenosis) Anatomical narrowing leading to ↑ airway resistance ↑ Risk of mechanical airway obstruction Disruption of central respiratory drive ↓ Sensitivity to increased CO2 in the ventral medulla oblongata Disruption of peripheral respiratory reflex pathways ↓ Sensitivity to CO2 levels in peripheral carotid bodies and aortic bodies Large head size forces neck into flexion when laying supine Immature airway sensitive to collapse when in flexion ↑ Hypotonia (decreased muscle tone) in REM sleep ↓ Signaling to brainstem Brainstem unable to mount appropriate ventilatory response to insufficient oxygen Upper airway collapse Apnea of prematurity Respiratory pauses >20 sec or pauses <20 sec with bradycardia (<100 beats per minute), central cyanosis, and/or oxygen saturation <85% in neonates born at <37 weeks gestation and with no underlying disorders causing apnea. Most apneas in apnea of prematurity are central or mixed. ↓ Breathing rate Bradycardia (<100 bpm) ↓ Oxygen to brain Poor neurodevelopmental outcomes (e.g. cognitive function, brain adaptive potential and plasticity) Hypoxemia (↓blood oxygen levels where SpO2 <85%) ↓ Oxygen and hemoglobin to mucous membranes (e.g. lips) & fingers and toes (periphery) Central & peripheral cyanosis (bluish discoloration) ↓ Oxygen to retina Abnormal growth of blood vessels in eyes Retinopathy of prematurity (changes in visual acuity and possible blindness) Death/impairment in cell function from lack of oxygen ↑ Risk of infant mortality Imbalanced oxygen intake and CO2 output in lungs Body transiently ↑ HR to unsuccessfully try to compensate for ↓ tissue oxygenation Respiratory failure Respiratory rate >60 ↓ Heart rate
↓ Blood pressure
Head bobbing Abdominal breathing
Skin mottling
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Published Mar 21, 2024 on www.thecalgaryguide.com