Hiccups in a Preterm LBW Baby on SCANU with HIE Grade 2 + PNA

• SCANU = Special Care Neonatal Unit (step-down/level II NICU)
• Preterm LBW = Low birth weight preterm neonate
• PNA = Pneumonia (neonatal)
• HIE 2 = Hypoxic-Ischemic Encephalopathy, Sarnat Stage II (moderate)

What Are Neonatal Hiccups?

• Afferent: phrenic nerve, vagus nerve, thoracic sympathetic chain
• Center: brainstem (medullary "hiccup center") + spinal cord C3-C5
• Efferent: phrenic nerve to diaphragm

Clinical Significance in THIS Baby

1. Physiological (Benign/Developmental)

• Hiccups in neonates, especially preterm, are largely physiological and expected. UCL research (Whitehead et al., 2019, Clinical Neurophysiology) showed each hiccup triggers large cortical brainwaves - likely helping the developing brain learn to regulate voluntary breathing by mapping diaphragmatic input.
• They are not a sign of distress on their own.

2. Respiratory Impact - IMPORTANT in PNA + Preterm

• Hiccups transiently interrupt the normal breathing pattern
• They can cause or worsen SpO₂ desaturations
• May trigger apneic episodes (especially relevant in preterm with immature respiratory drive)
• Brouillette et al. (J Pediatrics, 1980) showed hiccups can affect ventilation in clinically significant ways in young infants
• In a baby already on respiratory support or close monitoring, hiccup-associated desaturations need to be charted and distinguished from true apnea of prematurity

3. Neurological Significance - CRITICAL in HIE Grade 2

4. Hiccups as a Brainstem Integrity Marker

• Persistent or returning hiccups in an encephalopathic neonate can indicate preserved brainstem function - which is actually a positive prognostic sign in HIE
• Conversely, absent hiccups in a deeply encephalopathic neonate can indicate severe brainstem depression
• In HIE Grade 2, presence of hiccups generally reflects that the lower brainstem (medullary centers at C3-C5) is intact

5. Feeding-Related Trigger

• Post-feed hiccups are very common in neonates due to gastric distension stimulating the vagus
• In a preterm LBW baby with PNA, this increases risk of aspiration during hiccup episodes
• Ensure feed volumes are appropriate, burping/positional measures after feeds

Management Approach

• Observe: Is there a "hic" sound? Does it stop with holding/repositioning?
• If any doubt in HIE Grade 2: get aEEG or EEG - this is standard of care anyway in moderate HIE

• Monitor SpO₂ trend during hiccup episodes
• If causing significant desaturations in a baby on PNA treatment, adjust respiratory support accordingly
• Document frequency and duration

• Feed-related: reduce feed bolus volume, increase frequency; ensure correct NG/OG tube position
• Gastric distension: aspirate NG tube if tummy appears distended
• Temperature/irritation: ensure baby is comfortable and normothermic

• Confirm therapeutic hypothermia status (HIE Grade 2 is a standard indication if ≥36 weeks, ≥1800g, and within 6 hours of birth)
• Note: Preterm infants (<36 weeks) are generally NOT candidates for standard therapeutic hypothermia protocols - this is a critical point in a preterm LBW baby with HIE
• Continue seizure surveillance with aEEG
• Phenobarbitone is first-line if seizures confirmed (20 mg/kg IV loading dose)

• Ensure correct nasogastric tube placement to decompress stomach
• No pharmacological intervention is routinely needed for benign neonatal hiccups
• Baclofen, chlorpromazine, and metoclopramide (used in adults) are NOT used in neonates for hiccups

Bottom Line

1. Hiccups are common and mostly benign in preterm neonates - expect ~15 min/day
2. In the context of HIE Grade 2, always rule out subtle seizures with aEEG/EEG - do not dismiss as benign without evaluation
3. PNA makes respiratory impact more significant - watch for hiccup-triggered desaturations
4. Preserved hiccups = positive brainstem sign in an encephalopathic neonate
5. Therapeutic hypothermia eligibility must be assessed - most preterm LBW infants do NOT qualify for standard cooling protocols (requires ≥36 weeks GA)