06_McClure_06.indd 139 11/14/2012 11:22:43 PM CHAPTER 6 Neonatology 140 Routine care of the newborn Routine measurements Measure within 1hr of birth: \200 73.5kg ); Weight (term mean \200 Head circumference (mean 750cm). \200 Body length (mean 735cm); Usually babies are not weighed again until day 3 \200\2235 and then alternate daily whilst they remain in hospital. It is normal to lose weight after birth due to water loss, but wei ght loss should not exceed 10% of birth weight. Birth weight should generally be regained b y day 7. Subsequent mean growth is 20 \200\22330g/day until age 6mths. Vitamin K (phytomenadione) To prevent haemorrhagic disease of the newborn, vitamin K1 is ro utinely given within 48hr of birth. Dose 1mg IM (preferred) in term infants or alternatively 2mg orally on days 1 and 7, and, i f breastfeeding, also on day 28. Cord care Immediately after birth clamp the cord with a purpose-made device. Keep the umbil icus clean and dry. Antibiotic powders or sprays are not rou- tinely required. The cord usu ally detaches after 7 \200\22310 days. If umbilical granulomas develop, clean with alcohol wipes and consider chemical cau- tery (silver nitrate stick). Thermal care Babies should be delivered in a warm room, rapidly dried with a warm towel, an d then immediately wrapped or placed skin to skin on the moth- er \200\231s front and then covered with a warm towel and a hat. Routine observations Record soon after birth and then daily whilst in hospital. Mean pulse is 120 \200\223160beats/min, respiratory rate 35 \200\22345breaths/min, and temperature 36. 9*C. Infants should be nursed in an ambient temperature of 20 \200\223 22*C. Bathing Not required until day 2 or 3. Use tepid water. Genitalia should be cleaned super \201 cially only. Do not retract foreskin; it is attached to the glans. Biochemical screening In the UK, all infants should undergo a screening heel prick blood te st placed on a speci \201 c card between day 3 and 10 ( \200\230Guthrie \200\231 test). Re gional variation exists, but commonly screened diseases include: \200 i phenylalanine); congenital hypothyroidism(i TSH); Phenylketonuria ( cystic \201 brosis (i immune-reactive trypsin). Medium chain acetyl-CoA de \201 ciency. Sickle cell disease. \200 06_McClure_06.indd 140 11/14/2012 11:22:43 PM ROUTINE CARE OF THE NEWBORN 141 Positive tests require follow-up and more detailed testing. Newborn hearing screening All infants in the UK will have their hearing screened (otoacoust ic emis- sion \200\224OAE) within the \201 rst 4wks of life. Automatic auditory brainstem re- sponse (AABR) testing is carried out if any uncertainty in OAE response. Neonatal immunization See also b pp.728 \200\223729. In several countries hepatitis B immun iza- tion of all newborns is recommended. In the UK, immunization is only offered to infant s of seropositive mothers. Similarly, in the UK, Bacille Calmette \200\223Gu rin (BCG) sho uld be offered to babies born to parents of ethnic groups or communities with a high incide nce of close contact with a sputum-positive case for tuberculosis (TB). 06_McClure_06.indd 141 11/14/2012 11:22:43 PM CHAPTER 6 Neonatology 142 Milk feeding Methods \200 Bottle. \200 Tube feeding (if too ill/immature to suck). \200 \200 Naso/oro-gastic tube. Silastic naso-jejunal tube (severe gastro-oesophageal re \202 ux (GO R), aspiration, or recurrent apnoeas). Gastrostomy (if required long term, older children). Breastfeeding Breast feeding is a learned skill for both mother and baby. Establishing feed ing can take time, and it is vital that good support is available (breast feeding advisors or midwifes with appropriate training). Advantages d \200 \200 i \200 d \200 \200 d \200 d \200 d \200 Maternal post partum hemorrhage. maternal contraceptive effect. Mild Bonding. Maternal breast cancer risk. Cheap. Infant mortality (less relevant in developed world). GI and respiratory infection rate. Lat er autoimmune disease incidence (e.g. type I diabetes mellitus, atopic diseases). i later IQ. (cid:1) \200 Problems \200 \200 Cracked/sore nipples. Maternal anxiety (breast fed babies can gain weight slower than their bottle-fed couterparts \200\224give reassurance and support). Small risk of hypernatraemic dehydration if low milk intake (suspect if weight loss >10%). Contraindications \200 \200 \200 \200 \200 +ve maternal HIV status (in developed countries). Certain maternal medications (e.g. amioda rone). Maternal herpes zoster over breast. Infantile galactosaemia or phenylketonuria (PKU) . Primary lactose intolerance (very rare). Expressed breast milk (EBM) Usually mother \200\231s own breast milk, but some units have d onor breast milk banks which can be of value, particularly in extreme preterm infants. EBM is usually used to establish feeding in preterm infants, but is also useful when top-up feeds are required, if mother and baby are separated for any reason, or if there are other maternal problems e.g. cracked/sore nipples or breast engorgement. Once expressed, can refrigerate and use within 24 \200\22348hr, or freeze and use for up to 3mths. 06_McClure_06.indd 142 11/14/2012 11:22:43 PM MILK FEEDING 143 Formula milk Normal volume required is 150mL/kg/day. See Box 6.3 for different types of for mula milk available. Advantages \200 \200 Paternal involvement. Milk intake determined. Problems \200 \200 \200 Constipation. Oral thrush. Milk bezoars. Box 6.3 Types of formula milk available \200 Cow \200\231s milk formula: standard milk used. Extensively modi \201 ed, e.g. to d solute load, i iron and vitamins. Formula used from birth is predominantly whey protein, whilst \200\230follow on \200\231 milks (for \200\230hungrier \200\231 infants >6mths old) are pr edominantly casein-based Soya milk: or lactose intolerance, but use not now recommended due to high levels of phyto-oestrogens and availability of other alternatives Hydrolysed cow \200\231s milk formula: peptides. Indicated for prophylaxis or treatment of cow \200\231s o r soya milk protein allergy. Elemental formulas: hydrolysed to amino acids. Indicated for s evere milk protein allergy or malabsorption. In addition, many specialized formula milks ex ist for conditions such as: preterm/LBW infants; gastro-oesophageal re \202 ux (thickened with cornstarch); metabolic diseases; lactose intolerance (lactose- free milk); poor growth (high energy formulas); malabsorption, e.g. Pregestimil . previously recommended for cow \200\231s milk protein allergy e.g. Nutramigen . Contains short e.g. Neocate . Cow \200\231s milk protein is fully Trophic feeding (gut-priming) The term describes practice of feeding small milk volumes (0. 5 \200\2231mL/kg/hr of EBM) to enhance gut structure and function in infants too ill or imm ature to tolerate substantive milk feeds. Evidence suggests that in the preterm infant it i mproves GI motility and function, as well as achieving clinical outcomes of i weight gain, i head growth, d infection risk, and improved later milk tolerance. 06_McClure_06.indd 143 11/14/2012 11:22:43 PM CHAPTER 6 Neonatology 144 Routine neonatal examination Each baby must be examined at least once in the \201 rst wee k, usually on day 1 after birth. Such child health surveillance can be done by a hospital p ediatrician, advanced neonatal nurse practitioner, general practitioner, or specially train ed midwife/nurse. Purpose \200 \200 \200 \200 Maternal reassurance. Health education; explaining common variations. Detecting asymptomati c problems, e.g. congenital heart disease, DDH. Screening for rare, but serious conditions. Order of examination \200 \200 Attending midwife: ask if there are a Mother: medical history, family history, antenatal an d obstetric history, and social history. Ask about feeding and whether baby has passed meco nium/urine. when baby is quiet (if needed use calming techniques like Baby: paci \201 ers, sucking a clean \201 nger, examination after a feed) note: \200 \200 \200 \200 \200 ny concerns or problems. check patient notes for relevant details of the maternal general posture and movements; skin color; listen to the heart and lungs; examine the eyes for size, strabismus ( using an ophthalmoscope examine the eyes for bilateral red re \202 exes to exclude cataract or retinoblastoma (see b pp.614, 916). b pp.908 \200\223910); The remaining examination should proceed as described in the box opposite. 06_McClure_06.indd 144 11/14/2012 11:22:44 PM ROUTINE NEONATAL EXAMINATION 145 Rest of routine neonatal examination The baby should be completely undressed. Examination proceeds as follows in head to toe ord er: \200 Cranium: 33 \200\22337cm at term), assess skull shape, fontanelle positions, tension, and s ize (anterior may be up to 4cm x 4cm, posterior 1cm) Face: Visualize and palpate palate for possible clefts Ears: Neck: Chest: (normal 40 \200\22360/min), pattern, and effort. Palpat e precordium and apex beat Abdomen: inspect shape and umbilical stump. Check for inguinal h ernias. Palpate for masses, liver (normally palpable up to 2cm below costal margin), spleen (normally palpable up to 1cm), kidneys (normally palpable), bladder Genitalia: girls \200 \224 \200 boys \200\224 \200 descended testes (N.B. retractile testes are normal) measure maximum occipital-frontal circumference (normal assess any dysmorphism, nose, chin size. Inspect mouth. \200 \200 assess position, size, shape, and external meatus patency inspect and assess movements; pal pate clavicles. assess shape, symmetry, nipple position, respiratory rate inspect (N.B. the clitoris and labia are normally large) assess size, shape, position of ur inary meatus; palpate for Palpate the arch abnormalities) Anus: Spine: lipoma/pigmentation (may indicate underlying a bnormality); Limbs: assess symmetry, shape, passive and active movements, digit number and shape. Assess palmar creases. Examine hips for DDH (see b p.748) CNS: pulling baby to sitti ng position by holding wrists, and ventral suspension (baby should be able to hold head alm ost horizontally), check moro re \202 ex (symmetrical?) (see b p.558) Finally, check that urine and meconium were passed within the \201 rst 24hr femoral pulses (absence or weakness may indicate aortic \200 assess position and patency inspect for deformity and sacral naevi/dimple/pit/hair patch/ in addition to evaluation of above: assess tone during handling, 06_McClure_06.indd 145 11/14/2012 11:22:44 PM CHAPTER 6 Neonatology 146 Normal variations and minor abnormalities Skin \200 \200 \200 Vernix: Peripheral cyanosis: Post-mature skin: mature babies. Resolves, but topical emollie nts often bene \201 cial. normal \200\230cheesy \200\231 white substance on skin at birth. normal in \201 rst few days after birth. dry peeling skin, prone to cracking, common in post- Head \200 Skull molding: molding and are harmless. Resolves within 2 \200\2233 days. Pre-auricular pi ts, skin tags, or accessory auricles: be associated with hearing loss or other abnormalitie s. Test hearing and consider surgical referral for cosmetic reasons. Caput succedaneum, chi gnon, and cephalhaematoma: overriding skull bones with palpable ridges are part of usually isolated, but can see b p.126. Eyes \200 Blocked lacrimal duct leads to recurrent sticky eye; responds to regular eye toilet until d ucts open. This may persist for months, but only consider surgery if >12mths. If purulent t hen secondary bacterial conjunctivitis is likely. Take swab for M, C&S (including swab for chlamydia). Treat with antibiotic eye drops (see also b p.918). Subconjunctival hemorrhage: cord around the neck. Harmless and resolves within a few weeks. associated with precipitate deliveries or Mouth \200 \200 \200 Epstein \200\231s pearls: Tongue-tie: Ranula: cyst). Oral candidiasis (thrush): oral antifu ngal, e.g. nystatin suspension 1mL 6-hourly. self-resolving white inclusion cysts on palate/gums. shortened tongue frenulum (see b p.882). self-resolving bluish mouth \202 oor swelling (mucus retention mucosal white \202 ecks and erythema. Treat with Heart See b p.228. Murmurs are detected in 1 \200\2232% of all newborns, but only 1 in12 w ill represent congenital heart disease. If murmur heard, evaluate in context of other clinical \201 ndings (cyanosis, signs of he art failure, peripheral pulses). An innocent heart murmur is likely \200 Murmur is grade 1 \200\2232/6, systolic, not harsh, loudest at the left sternal edge. Remai ning cardiovascular examination is normal. Good evidence exists to support the use of pre and post-ductal satu- ration readings (right arm = pre, foot = post) as part of assessment of a pathological murmur. ECG and 4-limb BP should also be performed. Echocardiography should be obtained in infants where there is cli nical concern. 06_McClure_06.indd 146 11/14/2012 11:22:44 PM NORMAL VARIATIONS AND MINOR ABNORMALITIES 147 If murmur persists in an otherwise well infant, in whom no echocardiog- raphy has been perf ormed, then arrange for repeat examination in a few days to weeks and consider referral for cardiac assessment. Umbilicus See also b pp.874 \200\223875. \200 Umbilical hernia: strangulates and almost all spontaneously resolve within 12mths. Single u mbilical artery: associated with several syndromes and IUGR. protuberant swelling involving the umbilicus. Rarely usually isolated and of no signi \201 cance, but can be Genitalia \200 Undescended testes: \200\230persuaded \200\231 into the scrotum). If still undescended at 1yr refer to a surgeon (see b p.878). Hydrocele: surgeon (see b p.868). Vaginal mucoid or b loody discharge: withdrawal. Almost always spontaneously resolves. Vaginal/hymenal skin tag s: Inguinal hernias can rarely be present from birth. Refer to a surgeon. N.B. There is a r elatively high likelihood of strangulation/incarceration. differentiate from retractile testes (can be common and most resolve by a year. If persists refer to a due to maternal estrogen \200 spontaneously shrink (b p.881). Limbs \200 found in 72% of normal babies. May be associated Single palmar crease: with chromosomal abnormalities, e.g. trisomy 21. Polydactyly: Refer t o a surgeon. Syndactyly: familial. If toes only are affected require no treatment. Postural deformities: malpresentation, e.g. breech. Positional talipes is usually equinovarus or ca lcaneovalgus. If affected joint can easily be massaged back to normal neutral position, def ormity will rapidly resolve. If \201 xed (structural) refer to orthopedic surgeon/physiot herapist. These children are also at increased risk of DDH (see b p.748). can be isolated or associated with other abnormalities. most common between the second and third toes. Often common, especially after oligohydramnios or Miscellaneous \200 \200 see b pp.130 \200\223131. Jaundice: Sacral coccygeal pits: require spinal imaging. Breast swelling: lactate. Spontane ously resolves over several weeks. If does not resolve then endocrinology investigation is warranted. require no action if within natal cleft. Higher pits almost always due to maternal hormones and may 06_McClure_06.indd 147 11/14/2012 11:22:44 PM CHAPTER 6 Neonatology 148 Newborn \202 uid and electrolyte balance Normal \200 \200 775% term, 785% at 26/40). The newborn baby is largely water ( There is a large extracellular compartment (65% of body weight at 26/40 compared to 40% by term, 20% in adult). There is a rapid loss of extracell ular \202 uid after birth. Decreased pulmonary vascular resistance increases blood \202 ow to left atrium, thereby inducing increased Atrial Natriuretic Peptide release (i GFR/d Na+ reabsorbtion/ d rennin-angiotensin aldosterone system). Physiological increased urine o utput at Na/K ATPase activity is low at birth, but increases steadily (Na/K ATPase is respo nsible for reabsorbing Na+ from renal tubular lumen, in turn creating a gradient to allow r eabsorption of Glucose, Na+ and amino acids. Immature infants have lower enzyme activity. \200 \200 712 \200\22324hr after birth. Preterm babies have \200 \200 \200 \200 A variable ability to excrete a sodium load. An excellent ability to deal with water load. Modulated by ADH (osmo and baro-receptors). A tendency to lose sodium in urine over \201 rst weeks as the increased glomerular \201 ltration rate (GFR) exceeds ability to resorb Na+. A high transepidermal water loss (TEWL). Evaporation from immature skin, <28/40. To re duce nurse in incubator with 80% humidity Respiration related water losses (ventilated and spontaneously breathing infants) can be countered with warm-humidi \201 ed gasses. Sick in fants (e.g. respiratory distress syndrome (RDS)) will have delayed dieresis; \200 + will further delay diuresis and may worsen giving additional Na outcome; attempts to induce diuresis (e.g. with Furosemide) unlikely t o be helpful. Postnatal weight loss \200 Weight loss after birth is normal; \200 \200 Rising sodium suggests dehydration (term a nd preterm infants). Failure to lose weight may suggest \202 uid retention/overload. Infa nts with >10% weight loss require further assessment of feeding; \200 \200 \200 \200 \200 \200 up to 10 % in well term infants over the \201 rst week of life; greater in preterm/VLBW. \200 \200 risk of hypernatraemic dehydration; usually breast-fed infants with unrecognized poor feedi ng; weigh all babies day 3 (some suggest day 5); check U&E if weight loss >12%; support mot her with breast expressing/top-up feeds; may require admission/NG feeds/IV \202 uids 06_McClure_06.indd 148 11/14/2012 11:22:44 PM NEWBORN FLUID AND ELECTROLYTE BALANCE 149 Speci \201 c disturbances Hyponatraemia \200 \200 + < 130mmol/L. Na Causes: \200 \200 \200 \200 \200 \200 \200 \200 water overload (most common in \201 rst-week); maternal \202 uid overload; iatrogenic; sick infant (e.g. birth asphyxia, sepsis); excess renal loss (common \200\230late \200\231 cause in preterm infants); GI loss, e.g. diarrhea, NG aspirates, high output stoma; draina ge of ascites/CSF; other (e.g. hypoadrenalism of any cause, Bartter syndrome/Fanconi syndro me). \200 Symptoms: Treatment: supplementation) Take care as too rapid correction can cause neurologi cal damage. irritability, apnoeas, seizures. dependent on underlying cause (e.g. \202 uid restriction / Na+ Hypernatraemia \200 \200 + >150mmol/L. Risk of seizures if Na Causes: normally retain water also). Two major at-risk groups: \200 water depletion (usual), excess Na+ administration (unusual as extreme preterm infants in \201 rst days of life (excess water losses, e.g. TEWL); breast -fed infants with poor intake (see b p.142). Treatment: increase \202 uid intake (caution with rapid correction). Hypokalaemia K \200 + <2.5mmol/L \200\224causes: excess losses (diarrhea, vomiting, NG aspirate, stoma, renal/ diuretics); inadequate intake (failure to recognize daily requirement, e.g. TPN). Correct with supplementation (IV or enteral): \200 caution with enteral if GI disturbance ; \200 extreme caution with IV infusion as risk of heart arrythmia. Hyperkalaemia K \200 \200 \200 + >7.5mmol/L OR >6.5mmol/L and ECG changes. Failure of K+ excretion, e.g. renal failure. Causes: Treatments: \200 \200 \200 myocardial stabilization: calcium gluconate; elimination: calcium resonium, dialysis; re-di stribution: salbutamol, insulin. 06_McClure_06.indd 149 11/14/2012 11:22:44 PM CHAPTER 6 Neonatology 150 Respiratory distress syndrome RDS refers to lung disease caused by surfactant de \201 cien cy. The disease is largely seen in preterm infants. RDS is rare >32wks gestation. Causes Surfactant de \201 ciency causes alveolar collapse, increased work of breathing and hypoxia (due to intrapulmonary shunting of blood). Increased risk of RDS is associated wit h CS delivery; hypothermia; perinatal hypoxia; me- conium aspiration; congenital pneumonia; maternal diabetes mellitus; past family history (see b p.152). Presentation Cyanosis, tachypnoea, chest in drawing, grunting within 4hr of birth. If untre ated, the disease worsens over 48 \200\22372hr and then (depending on severity) resolves ov er 5 \200\2237 days. Investigations \200 (b p.156): bilateral, diffuse \200\230ground-glass \200\231 appearance CXR (generalized atelectasis), airway bronchograms, reduced lung volume (see Fig, 6.3). SpO \200 2 monitoring and blood gasses. Management \200 Good delivery room resuscitation. This may involve intubation and administration of surfact ant (extremely preterm) or nasal CPAP. Respiratory support will depend on the severity. May need O CPAP (b p.160), or ventilation (b pp.162 \200\223165). Surfactant (Curosurf ventila tion, and should be considered in all extremely preterm (<27/40) infants and when oxygen re quirement exceeds 30 \200\22340%. \200 \200 \200 Antibiotics: been excluded, as it ca n mimic or coexist with RDS. Nutrition tube feeds with minimal volumes and slowly increase as tolerated. If unstable, start parenteral nutrition after 24 \200\22348hr. 2, nasal or Survanta ) requires intubation and given as bolus down ETT; give 2nd dose if oxygen requirement remains high (FiO further dose s are sometimes required. 2>0.3); e.g. penicillin and gentamicin, until congenital pneumonia has : use IV \202 uids until the baby is stable. Then start gastric Prognosis The majority have a good recovery. Mortality is 5 \200\22310% and depends on seve rity and gestation. Bronchopulmonary dysplasia may develop (715% of cases, inversely propor tional to gestational age). Prevention \200 Corticosteroids (betamethasone/dexamethasone, 2 doses, 12-hourly) given to mother 1 \200 \2237 days before birth decreases incidence and mortality by 40%. Maximum bene \201 t 24hr after \201 rst dose and lasts 7 days. Treat co-existing morbidities that inhibit surfact ant production developing, e.g. hypothermia, acidosis, infection. 06_McClure_06.indd 150 11/14/2012 11:22:44 PM RESPIRATORY DISTRESS SYNDROME 151 06_McClure_06.indd 151 11/14/2012 11:22:44 PM CHAPTER 6 Neonatology 152 Acute respiratory diseases All of the diseases presented below have signs of respiratory di stress (b p.150). Cerebral hypoxia, congenital heart disease, and metabolic aci- dosis can induce respiratory distress (suspect if CXR is normal). Transient tachypnoea of the newborn (TTN) \200 \200 Caused by delayed clearance/absorption of lung \202 uid after birth. Presents within 4hr after birth. Common after elective CS. CXR: shows streaky perihilar changes and \202 uid in lung horizontal \201 ssures. Treatment: supplemental O 2. Consider nasal CPAP and anti biotics. Spontaneously resolves within 24hr. \200 Congenital pneumonia \200 \200 Caused by aspiration of infected amniotic \202 uid. Associated with prolonged rupture of membranes (PROM), chorioamnionitis, fetal hypoxia. Usually group B streptococci, listeria, chlamydia. Presents in \201 rst 24hr. CXR: patchy shadowing and consolidation. Respirator y support: and gentamicin) after septic screen; chest physiotherapy. Prognosis: pulmonary h ypertension of newborn (PPHN). Escherichia coli, other Gram \200\223ve bacteria, \200 antibiotics (benzylpenicillin, or ampicillin if listeria, depends on severity and associated sepsis or persistent Meconium aspiration syndrome (MAS) (1 \200\2235/1000 live births) \200 \200 5% of term infants with meconium-stained liquor develop MAS. Hypoxia results in gasping and meconium passage combination that leads to aspiration. Meconium aspiration inhibits surfac tant, obstructs the respiratory tract, and induces pneumonitis. Presents with respiratory d istress soon after birth. Associated with pulmonary air leaks and PPHN. CXR: generalized lu ng over in \202 ation with patchy collapse/consolidation +/ \200\223 air leaks. Prevention : to prevent further hypoxia and gasping. If baby is apnoeic at birth, visualize the larynx and suck out any meconium from larynx/trachea. Tracheal suction is not recommended for vig orous infants. Treatment: (IPPV) or high frequency oscillatory ventilation (HFOV) if ventil ation required; surfactant; antibiotics (since listeria can cause antenatal meconium passag e); treat any PPHN (b p.168); consider ECMO if severe. mortality <5%. Survivors do well, bu t there is i risk of Prognosis: asthma and, if extracorporeal membrane oxygenation (ECMO) i s needed, neurological sequelae. in utero, a if liquor is meconium-stained, delivery should be expedited supplemental O2; intermittent positive pressure ventilation Pulmonary air leaks Commonly secondary to other respiratory disease (e.g. RDS, MAS) or to a ssisted ventilation. 06_McClure_06.indd 152 11/14/2012 11:22:44 PM ACUTE RESPIRATORY DISEASES 153 Pneumothorax Spontaneous pneumothorax occurs in 72% term infants. Incidence is increased in prematurity and respiratory disease. \200 Features: If large, present with respiratory distress. Tension pneumothorax (see b p.214) i s life-threatening (signs: respiratory distress, cyanosis, mediastinal shift away from affe cted side, d chest movement and air entry on affected side, transillumination lights up aff ected side). CXR: collapsed lung (see Fig. 6.4). Treatment: are severe or worsening, insert chest drain (b p.214). In emergency, perform needle aspiration before chest drain. Prognos is: RDS. Also i risk of periventricular hemorrhage in preterms. majority are small, asymptomatic, and resolve spontaneously. shows ipsilateral translucency, lack of peripheral lung markings, none if asymptomatic. Give O2 as required. If symptoms excellent in term infants. Mortality is doubled in infants with Pulmonary interstitial emphysema (PIE) Air leak into lung parenchyma results in small airwa y and alveolar col- lapse. Follows high IPPV, particularly in preterm infants with severe R DS or MAS. \200 Signs: inspiratory crackles. CXR lucencies/bullae, generalized or local ( see Fig. 6.5). Treatment: superior. Unilateral PIE: nurse infant with affected side down. I n refractory cases consider selective intubation to ventilate the healthier lung. Prognosis : bronchopulmonary dysplasia. respiratory distress; chest hyperexpansion; poor air entry; coarse (b p.157): hyperin \202 ation; \200\230honeycomb \200\231 pattern of cystic high FiO2, low PIP, low PEEP, fast rate IPPV; HFOV may be mortality 25 \200\22350%. There is an increased risk of Pneumomediastinum Often preceded by asymptomatic pneumothorax/PIE. \200 CXR: and splayed from below ( \200\230sail \200\231 sign). Treatment: translucency around the heart extending superiorly; thymus lifted usually no treatment is required. Pneumopericardium: usually occurs with other air leaks associated with IPPV and can lead to cardiac tamponade (with quiet heart sounds, hypo- tension, bradycardia, cyanosis). \200 \200 \200 CXR: Treatment: Prognosis: translucency around the borders of a small heart. urgent needle drainage inserted under the xiphisternum. high mortality if symptomatic. Pneumoperitoneum Air can occasionally track into the peritoneum from a pulmonary air leak. AXR con \201 rms the diagnosis. Severe abdominal disten- tion could impair ventilation. Dr ain if symptomatic. Massive pulmonary hemorrhage (1/1000 live births) Usually due to haemorrhagic pulmonary oed ema in VLBW infants. Small bleeds are associated with tracheal trauma from ETT or suction. It is associated with: PDA, heart failure, PIE, hydrops foetalis, perinatal hypoxia, sepsis , coagulopathy, \202 uid overload, surfactant therapy. 06_McClure_06.indd 153 11/14/2012 11:22:44 PM CHAPTER 6 Neonatology 154 Signs \200 \200 \200 \200 Rapid systemic collapse. Profuse bloodstained \202 uid welling up from upper airway. Resp iratory crackles on auscultation. CXR. Virtual \200\230white out \200\231. Consider echoca rdiography to detect PDA. Treatment i \200 \200 \200 \200 \200 \200 O2 and ventilatory pressures. Frequent endotracheal suction. Correct hypovolaemia and coagu lopathy. Consider blood transfusion. Consider surfactant. Treat known associations. Milk aspiration Term infants can accidentally aspirate a feed. The usual causes are: \200 Swallowing incoordination, e.g. preterm, neurological disease. \200 Upper airway or oeso phageal disorders, e.g. tracheo-oesophageal \201 stula, gastro-oesophageal re \202 ux. Presentation Sudden choking or respiratory distress during or after a feed, often with exce ssive milk in the mouth, or aspiration pneumonia. CXR: normal or patchy collapse/consolidation in the upper lobes. Treatment If well, observe only. If unwell, respiratory support and broad spectrum antibiot ics are needed. Investigate cause and use gastric or naso- jejunal tube feeding. Period of IV \202 uids or feeding may be necessary. Apnoea Apnoea can result from any severe illness. Management \200 \200 Support respiration. Investigate and correct primary cause. Apnoea of prematurity \200 \200 \200 i as gestation d). Common below 34wks gestation (incidence Between episodes the infant is well. Consider and e xclude other diagnoses (see b pp.48, 128). Treatment Tactile stimulation, blood transfusion, continuous tube gastric feeds, caffeine o r theophylline, nasal CPAP, or IPPV. Prognosis Short-lived apnoeas appear to cause no harm and should resolve by 34wks gestation . 06_McClure_06.indd 154 11/14/2012 11:22:44 PM ACUTE RESPIRATORY DISEASES 155 06_McClure_06.indd 155 11/14/2012 11:22:45 PM CHAPTER 6 Neonatology 156 Neonatal X-rays Fig. 6.3 Respiratory distress syndrome. Bilateral, diffuse \200\230ground-glass \200\231 a ppearance (due to generalized atelectasis), airway bronchograms, reduced lung volume. 06_McClure_06.indd 156 11/14/2012 11:22:45 PM NEONATAL X-RAYS 157 Fig. 6.4 Left tension pneumothorax. Left chest hyperlucency and hyperin \202 ation, collap sed left lung (absence of peripheral lung markings), mediastinum shifted to the right. Fig. 6.5 Pulmonary interstitial emphysema. Bilateral lung hyperin \202 ation (hyperlucency and downward displacement of diaphragm) with multiple radiolucent cystic areas. PIE may be unilateral. Isolated large bullae may appear. Cardiac compression may occur. 06_McClure_06.indd 157 11/14/2012 11:22:45 PM CHAPTER 6 Neonatology 158 Fig. 6.6 Bronchopulmonary dysplasia. Hyperexpansion, diffuse patchy collapse and \201 bro sis interspersed by radiolucent cystic areas and area of emphysema in left lower lung. Fig. 6.7 Congenital diaphragmatic hernia. Air- \201 lled bowels loops \201 ll left hemit horax with absence of left lung markings and mediastinal shift to the right. 06_McClure_06.indd 158 11/14/2012 11:22:46 PM NEONATAL X-RAYS 159 Fig. 6.8 Necrotizing enterocolitis. Dilated loops of thick walled bowel and pathognomonic a ppearance of gas in the gut wall (pneumatosis intestinalis) evident in the left lower abdom en (gut seen side on) and center (gut seen end on \200\223 \200\230halo sign \200\231). G as evident in the portal venous system may also be seen and indicates severe disease (not p resent on this X-ray). 06_McClure_06.indd 159 11/14/2012 11:22:46 PM CHAPTER 6 Neonatology 160 Neonatal respiratory support Supplemental oxygen Excess oxygen is toxic, particularly in pr eterm infants. All infants receiving supplemental oxygen should have SpO2 monitoring as a m inimum. If sig- ni \201 cant hypoxia, consider an arterial line to directly monitor PaO2. Term infant \200\231s oxygen saturation levels should be >95% in air \200\224usually (cid:2 )97%. (cid:1) The \200\230correct \200\231 saturation range for preterm ((cid:1)32/40, (ci d:1)1500g) infants has not been determined. Maintaining SpO2 around 90 \200\22395% and avoi dance of \200\230swings \200\231 in either saturation or FiO2 is reasonable whilst evidenc e from large RCTs is awaited. Supplemental oxygen can be given via: \200 \200 Head box (concentration easily monitored). Nasal cannula <2L/min (cannot monitor effective FiO gas \202 ow rate, FiO2, and tidal volume, can \200\231t humidify effectively). >2L/mi n. Can be effectively humidi \201 ed. High \202 ow nasal cannula Generates CPAP effect. 2 \200\224depends on CPAP Prevents airway collapse and loss of lung volume. Maintenance of functional residual c apacity above closing volume reduces work of breathing. Uses \200 \200 \200 RDS and respiratory support, particularly for preterm infants. Post-extubation. In upper ai rway obstruction. Method \200 \200 Nasal mask or binasal prongs, rarely face mask or via ETT. Usual pressure is 5 \200\2236cmH but i risk of pulmonary air leaks as pressure i. Some equipment can deliver bi-level CPAP with or without synchronization to spontaneous breaths. 2O. Probable safe upper level is 8cmH2O, Complications \200 Pulmonary air leaks, e.g. pneumothorax. (particularly if treating RDS in an infant who has not received surfactant). Nasal trauma. Baby upset leading to hypoxia. i Upper GI distensio n or perforation (insert gastric tube on free drainage to reduce risk, rarely seen with mod ern equipment). \200 \200 Airway resistance and effort of breathing. \200 Positive pressure ventilation Intermittent positive pressure ventilation (IPPV) See b p.162 . High frequency oscillatory ventilation (HFOV) See b p.164. Synchronized ventilation Nomen clature confusing, but includes the following: \200 Synchronized intermittent positive pressure ventilation (SIPPV)/assist control/patient-trig gered ventilation (PTV): every spontaneous patient breath can trigger time-limited positive pressure in \202 ation. 06_McClure_06.indd 160 11/14/2012 11:22:47 PM NEONATAL RESPIRATORY SUPPORT 161 Synchronized intermittent mandatory ventilation (SIMV breaths is pre-set; any other spontan eous patient breaths are unassisted \200\224in case of apnoea the set rate is given. Pressu re support: all spontaneous breaths are supported by positive pressure for as long as inspi ratory \202 ow continues above a de \201 ned threshold. Can be combined with other modes . ): rate of triggered Studies in newborn infants show no particular advantage for SIPPV or SIMV compared to conve ntional IPPV during acute stages of respiratory illnesses such as RDS. May be useful during weaning, or if infant is not synchronizing with ventilator. Smaller infants may not be abl e to trigger breaths (older ventilators). Autocycling can cause over ventilation in PTV. Extracorporeal life support (ECLS) Provided only in a very small number of specialist cente rs in the UK. Also known as extracorporeal membrane oxygenation (ECMO), ECLS reduces mortal ity in severe respiratory disease, e.g. meconium aspiration syn- drome, persistent pulmonar y hypertension of the newborn.1 Early transfer to an ECLS center is important as these infa nts are often critically unwell. Criteria for eligibility: severe, but reversible cardiac or respiratory disease and oxygena tion index persistently >30 \200\22340 where: Oxygenation index = [(mean airway pressure \227 FiO2)/PaO2 (kPa)] \227 100 FiO2 is expressed as a decimal, e.g. 30% O2 = 0.3 Contraindications \200 Weight <1.8kg. \200 Gestation <34wks. \200 Severe congenital malformation. \200 Intracranial hemorrha ge or poor CNS prognosis (e.g. severe HIE). \200 Coagulopathy. Technique Blood taken from a major cannula is passed through a membrane oxy- genator and th en returned to the body. Blood is heparinized (activated clotting time 2 \200\2233 \227 no rmal) and low level conventional ventilation is main- tained. ECMO is maintained until dise ase recovery. May be: \200 double lumen cannula in right jugular vein or right Venous \200\223venous: atrium; Venous \200\223arterial: right carotid artery. blood drawn from right jugular vein and returned to Outcome Survival rates are high for reversible lung pathologies. Up to 10% of ECMO survivor s suffer major long-term problems. Complications include brain injury (secondary to neck ve ssel trauma, thromboembo- lism, CNS hemorrhage, complication of pre-ECMO disease/therapy) a nd peripheral thromboembolic phenomenon, e.g. may cause renal failure. Reference 1 UK Collaborative Trial Group (1996). UK collaborative randomized trial of neona tal extracor- poreal membrane oxygenation. Lancet 348: 75 \200\22382. 06_McClure_06.indd 161 11/14/2012 11:22:47 PM CHAPTER 6 Neonatology 162 Conventional positive pressure ventilation IPPV via ETT with continuous \202 ow of heated and humidi \201 ed gas allows the non-paralyzed baby to breathe spontaneously. The ventil ator is time- cycled, pressure limited (TCPL) where the user sets the positive inspira- tor y pressure (PIP), inspiration time (Ti) and ventilator rate. In this mode the tidal volume is determined by the lung compliance. Some ventilators can adjust PIP within a set range to deliver a set tidal volume (volume guarantee). Some ventilators can terminate inspiration when a set volume is reached or when inspiratory \202 ow is declining below a threshold l evel. Whichever method is chosen the user must be familiar with the operation and limitatio ns of the ventilator. Indications \200 \200 \200 \200 \200 \200 \200 \200 \200 Worsening respiratory failure, e.g. RDS. Impending or actual respiratory arrest from any ca use. Recurrent apnoeas. Massive pulmonary hemorrhage. Severe cardiac failure. Persistent pu lmonary hypertension of the newborn. Severe congenital lung malformation, e.g. diaphragmati c hernia. Severe HIE. Anesthesia. Ventilation parameters \200 \200 \200 \200 \200 Peak inspiratory pressure (PIP). PEEP. TI and expiratory (TE) time (often expressed as I:E ratio). Inspired O Gas \202 ow (L/min) through ventilator circuit (may not be adjustable) . 2% or fraction inspired O2 (FiO2). Monitoring ventilation \200 Review and adjust ventilation settings soon after commencement (see Box 6.4 for care princi ples). Monitor blood gasses and adjust ventilation as appropriate. Acceptable limits will d epend on the clinical situation, however, as a guide in preterm infants; pH 7.2 \200\2237.3 5, PCO2 5 \200\2238kPa, PO2 6 \200\22310kPa, saturation 90 \200\22395%, expired tidal volum e around 5mL/kg. \200 2 is too low \200\224i FiO2, or i mean airway pressure (the latter by If PaO either i PIP, i PEEP, or d TE which will i rate as TI stays constant). Do the opposite if PaO2 is too hig h. If PaCO PIP, or d PEEP, or i rate. Do the opposite if PaCO2 is too low. 2 is too high \200\224i alveolar ventilation, i.e. minute volume, by i 06_McClure_06.indd 162 11/14/2012 11:22:47 PM CONVENTIONAL POSITIVE PRESSURE VENTILATION 163 Box 6.4 Care principles in assisted ventilation in newborns Endotracheal tube (ETT) Use correct size and secure appropriately. Elective intubation Give prior sedation with opiate, e.g. morphine or fen- tanyl, and muscl e relaxant, e.g. suxamethonium (ONLY if staff experi- enced in airway management are presen t). Minimal handling Reduces episodes of deterioration. Sedation/analgesia Evidence does not support routine use of morphine infusion for ventilate d preterm infants. (cid:1) Prolonged neuromuscular relaxation (e.g. Vecuronium) \200 \200 Consider in speci \201 c circumstances, e.g. severe meconium aspiration Give sedation/anal gesia to paralyzed infants, e.g. morphine infusion