An Introduction to Neonatology

The Neonatal Intensive Care Unit Neonatology is a subspecialty of paediatrics concerned with the care of newborn infants. Mostly this covers preterm and low birthweight infants, but also includes congenital abnormalities. The Neonatal Intensive Care Unit (NICU) at Addenbrooke’s is a Level 3 Unit, meaning you may see babies with quite complex needs and rare conditions. This introduction aims to give you an idea of some of the common things you might see on the ward round. If you have any further questions, please ask the team you are shadowing. Infant in an incubator Acute Neonatal Transfer Team (ANTS)

The Preterm Infant A preterm infant is an infant born earlier than 37 weeks gestation. The normal gestational period is 40 weeks. Preterm birth is common for twins. Preterm infants have many systemic difficulties, relating to the immaturity of their organs. It is useful to think in terms of organ systems in order to treat the neonate holistically. Respiratory Cardiovascular Gastrointestinal Neurological Metabolic Infection Infant in an incubator

Respiratory When infants are born prematurely, their lungs are underdeveloped. Surfactant is not produced until 36 weeks gestation, meaning they are at high risk of suffering from Respiratory Distress Syndrome (RDS). Infants are given surfactant and steroids and usually need ventilatory support. This can be invasive ventilation or non-invasive and you will see a variety of tubes and machines used. O2 saturations and respiratory rate are constantly monitored by machines. Invasive mechanical ventilation Non-invasive ventilation Nasal cannula

Cardiovascular Often in preterm babies there is a persistent connection between the aorta and pulmonary artery, a patent ductus arteriosus (PDA). Sometimes this closes spontaneously as the baby grows. However, it can sometimes cause shunting of blood away from the systemic circulation and into the pulmonary circulation. This can lead to pulmonary hypertension and organ ischaemia. PDAs can be treated with prostaglandin inhibitors (NSAIDs like ibuprofen) or surgical ligation. You may see some congenital heart abnormalities such as ventricular and atrial septal defects, or Tetralogy of Fallot. These can be visualised with an echocardiogram (ultrasound of the heart). Ductus arteriosus Echocardiogram

Gastrointestinal Preterm babies are at high risk of a serious gastrointestinal disease called necrotising enterocolitis (NEC). The intestines become inflamed and necrotic, which can lead to a perforation. Signs of NEC are a distended abdomen, feeding problems or vomiting. Treatment is with antibiotics or surgery. Preterm babies do not yet have a sucking reflex so need to be fed enterally (a nasogastric tube into the stomach) or parenterally (peripheral intravenous line to deliver fluids into the circulation). Mothers are encouraged to express breast milk for their baby, as breast milk can be protective against NEC. Nasogastric tube for enteral feeding Long line for parenteral nutrition Expressing breast milk

Neurological A hypoxic episode around the time of birth can cause hypoxic-ischaemic encephalopathy (HIE). This can lead to long term brain damage and impairment (e.g. developmental delay, epilepsy and cerebral palsy). Infants who suffer a hypoxic episode can be cooled to around 34°C for 72 hours, in order to halt inflammation and brain tissue injury. The cerebral vessels are delicate and prone to injury. Sometimes they can rupture and bleed into the ventricles causing an intraventricular haemorrhage (IVH). This can be assessed by cranial ultrasound. An IVH can resolve by itself, or lead to long term brain damage. Infant being cooled Cranial ultrasound showing an IVH

Metabolic Preterm infants have difficulties regulating temperature due to their small size and high energy demands. The incubator helps regulate body temperature. Measurements are taken regularly to monitor for signs of fever and infection. Jaundice is usually only a short-term problem for term babies. However, in preterm infants jaundice can persist for much longer as the liver is immature and cannot metabolise bilirubin. High levels of bilirubin can lead to brain dysfunction. Phototherapy uses light to break down bilirubin in the blood. Incubator Phototherapy

Infection With relatively immature immune systems, preterm babies are at increased risk of infection and sepsis. Infections can disrupt growth and development. It is therefore important all staff and visitors observe hand hygiene rules. The most common bacterial infection of neonates is with Group B Streptococcus (GBS). This is often transmitted from the mother and can be treated with benzylpenicillin. Many practical procedures are carried out on a sterile field to reduce contamination with Staphylococcus from the skin and avoid infections from intravenous lines. Sterile insertion of a central venous line

Congenital Abnormalities If you would like to remind yourself, here are some congenital abnormalities you have learnt about in anatomy and embryology. You may come across some of these on NICU. Patent ductus arteriosus, ventricular septal defects and atrial septal defects Tetralogy of Fallot Tracheo-oesophageal fistula and oesophageal atresia Cleft lip and palate Gastroschisis and exomphalos Spina bifida Cleft lip Exomphalos

Top Tips You will need to wash your hands every time you go into a different room on NICU to prevent infection spread. If you are unsure, just follow what everyone else in the team is doing. Most of the babies are in incubators that are often covered by blankets. This makes it difficult to see them unless you go right up to the incubator and lift the blanket. This is alright for you to do and often the consultant will encourage it! You learn a lot by observing the babies. There are a lot of acronyms used on NICU. If you are not sure what something means, just ask! It can really help your understanding. As well as the doctors, observe the role of nurses, dieticians and pharmacists. Consultants and doctors sometimes get confused about the different stages of medical students. If someone is teaching or asking questions that are beyond your stage of learning, explain to them what stage you are at and ask them if they could explain in a bit more detail to help you understand. Above all, have fun! Enjoy being in a clinical setting and take in as much as you can. This is very different to all the lectures and seminars you attend as a pre-clinical student, so make the most of this opportunity to learn some clinical medicine!