RECURRENT APNOEAS
History
Baby Carmichael is admitted to the neonatal unit on the day of birth because of a low blood glucose. He was born at 35 weeks’ gestation by vaginal delivery after 48 hours of ruptured membranes but an otherwise uneventful pregnancy. His birth weight was 2.0 kg (ninth centile). His mother had two previous pregnancies which resulted in liveborn infants. This baby was thought to be jittery within a few hours of birth, and blood glucose was 1.8 mmol/L. A breast-feed was attempted, but he did not latch on well. He was admitted to the neonatal unit at that point for a nasogastric feed, some blood tests were done and the blood glucose rose to 3.2 mmol/L after the first feed. At the age of 6 hours he became apnoeic and a neonatal nurse stimulated him and gave some oxygen. Over the next hour he had five more apnoeic episodes requiring stimulation, and on the last occasion he required a brief period of facemask intermittent positive pressure ventilation.
Examination
Baby Carmichael does not appear dysmorphic, jaundiced or cyanosed. He appears lethargic (reduced spontaneous movement) and his tone feels reduced on handling. Respiratory rate is 50/min with no signs of increased effort, oxygen saturation is 95 per cent in air, and heart rate is 180 beats/min. His temperature is 37.8C. Femoral pulses, heart sounds and breath sounds are normal. The abdomen is soft with normal bowel sounds. His fontanelle is normotensive. His palate and genitalia are normal.
INVESTIGATIONS
Normal
Haemoglobin 17 g/dL 14–22 g/dL
White cell count 21 109/L 10–26 109/L
Platelets 153 109/L 150–400 109/L
C-reactive protein (CRP) 7 mg/L 5 mg/L
Glucose 3.1 mmol/L 2.8–4.5 mmol/L
Venous blood gas
pH 7.17 7.35–7.42
PaCO2 7.1 4.7–6.0 kPa
Bicarbonate 19 20–26 mmol/L
Base excess 8.5 2.5 to 2.5 mmol/L
Questions
• What is the definition of an apnoea?
• What is the most likely reason for the recurrent apnoeas in this baby?
• What additional information about the mother and her treatment would be helpful?
• How should this baby be managed?
Medicine
An apnoea is an episode of cessation of breathing lasting more than 20 s, or a shorter time if there is bradycardia or a colour change. This is distinct from the normal newborn pattern of periodic breathing, where fast respiration alternates with pauses of up to 10 s.
Causes of apnoea in a newborn
• Apnoea of prematurity
• Lung disease, e.g. respiratory distress syndrome
• Congenital heart disease
• Sepsis
• Hypoglycaemia
• Hypothermia
• Sedative drugs (administered to mother in labour, or to baby)
• Neurological insults – cerebral haemorrhage, oedema or seizures
• Anaemia
• Gastro-oesophageal reflux
In this case, the most likely diagnosis is sepsis. The baby was born prematurely after prolonged rupture of membranes – both risk factors for sepsis. He was hypoglycaemic, a common finding in septic newborns, and he has had recurrent and worsening apnoeas. He is lethargic and has a slightly raised temperature. White cell count and CRP are unremarkable, but this is often the case early in the course of neonatal sepsis. The blood gas shows a mixed metabolic and respiratory acidosis, indicating hypoperfusion and hypoventilation. This would be typical of early-onset group B streptococcal (GBS) sepsis. There is no information provided about whether the mother had any microbiological samples taken, received intrapartum antibiotics, had a fever or had evidence of chorioamnionitis. These are all factors which would affect the risk of sepsis in the newborn. It is also important to know whether the mother received any drugs during labour which may suppress neonatal respiration, e.g. pethidine, or whether she uses any illicit drugs. Given the presence of two risk factors for early-onset GBS sepsis, if the mother had not received adequate intrapartum antibiotic prophylaxis, the baby should have been assessed, cultures taken and antibiotics commenced at birth. If this was not done as soon as the baby showed the first signs of jitteriness and hypoglycaemia, sepsis should have been suspected. This baby is now in a dangerous situation, where apnoeas may progress to a respiratory arrest. Management priorities are to secure the airway with optimal positioning of the head, ensure adequate breathing with either CPAP or intub ation, establish vascular access, give fluid boluses to achieve cardiovascular stability and administer antibiotics as early as possible. After this, further assessment for the source of the sepsis, and to exclude other causes of apnoea, can be undertaken.
KEY POINTS
• Apnoeas are a final common manifestation of many disease processes in the neonate.
• Any neonate with apnoeas requires prompt evaluation.
• Antibiotics must be administered urgently to a neonate with suspected early-onset sepsis.
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