Apnoea of prematurity is a developmental disorder of respiratory control that occurs in preterm infants born at < 34 weeks’ gestational age.
Apnoea of prematurity is defined as:
- Cessation of breathing (airflow) for ≥ 20 seconds, or
- Cessation of breathing (airflow) for < 20 seconds with vital changes
- Bradycardia (< 80 – 100 bpm or a drop in ≥ 30 bpm from baseline)
- Desaturation (< 85%)
Its prevalence is inversely related to gestational age. At < 28 weeks, almost all neonates are affected.
It usually occurs 2-3 days post-delivery. Apnoea on day 1 of life is not apnoea of prematurity.
Definition of terms
| Term | Definition |
|---|---|
| Periodic breathing | Cessation of airflow for periods less than 10 seconds occurring at least thrice in succession without change in vitals (no desaturation or bradycardia). Commonly seen in preterms 2 – 6 weeks of life during quiet sleep. Usually resolves by 39 – 42 weeks post-menstrual age. Prominent during active sleep and is eliminated by CPAP. |
| Intermittent hypoxia | Short and repetitive episodes of hypoxemia and desaturation without bradycardia or apnoea |
| Apnoea of infancy | Apnoea occurring in term babies. It is always pathological. |
| Persistent apnoea | Apnoea that continues past 37 weeks post-menstrual age |
| Extreme apnoea event | Apnoea of more than 30 seconds and/or heart rate < 60 bpm for > 10 seconds |
| Brief Resolved Unexplained Event (BRUE) | An acute, frightening event with apnoea, bradycardia, color change, or choking. Low-risk BRUE requires only parental education. |
Types of apnoea
| Classification | Description |
|---|---|
| Mixed apnoea (40 – 50%) | Contains elements of both central and obstructive apnoea |
| Central apnoea (30 – 40%) | Cessation of both airflow and respiratory effort |
| Obstructive apnoea (10 – 20%) | Cessation of airflow in the presence of continued respiratory effort. Due to secretions or the collapse of pharyngeal muscles |
- Pathophysiology
- Immature respiratory control
- Poor brainstem development
- Reduced CO2 sensitivity
- Hypoxia → apnoea (instead of tachypnoea)
- Abnormal reflexes
- Laryngeal reflex → apnea with feeds or secretions
- Vagal dominance → bradycardia
- High levels of GABA and adenosine → suppression of the central urge to breathe
- Poor pharyngeal tone and reduced chest wall compliance → airway collapse during sleeping
- Immature respiratory control
- Differentials – other causes of apnoea
- Maternal sedation
- Magnesium use peripartum
- Birth asphyxia
- Hypoglycaemia
- Early-onset sepsis
- Respiratory distress: apnoea might indicate worsening disease
- Causes of secondary apnoea
- Temperature instability
- Intraventricular hemorrhage
- Sepsis
- Necrotizing enterocolitis
- Pneumonia
- Gastroesophageal reflux or aspiration
- Electrolyte disturbances
- Investigations
- Sepsis screen
- Blood glucose
- Electrolytes
- Chest radiograph to rule out lung disease
- Cranial ultrasound to rule out intraventricular haemorrhage
- EEG to rule out seizures in some cases
- Polysomnography
- Treatment
- Positioning with the neck neutral
- Thermoneutral environment
- Minimal stimulation
- Gentile tactile stimulation during episodes
- Caffeine citrate
- Blocks adenosine receptors → increases respiratory drive
- Has a longer half-life and a higher therapeutic index than theophylline
- It also has fewer side effects
- Theophylline is rarely used
- CPAP if apnea persists despite caffeine
- Mechanical ventilation for severe or refractory cases
- Caffeine can be stopped once the neonate is apnea-free for 5 – 7 days (usually at 34 – 35 weeks postmenstrual age)
- Observe for 5 – 7 days before discharge
- Clinical course of apnoea of prematurity
- Starts day 2 – 3
- Peaks at 1 – 2 weeks
- Resolves by 34 – 36 weeks postmenstrual age
