Neobook — clinical reference

Respiratory Distress Syndrome (HMD) and Surfactant Replacement

Persistent Pulmonary Hypertension of the Newborn (PPHN)

Chronic Lung Disease (CLD)/Bronchopulmonary Dysplasia (BPD)

RESPIRATORY DISTRESS SYNDROME (HMD) AND SURFACTANT REPLACEMENT

Place any baby with respiratory distress <34 weeks or <1.8kg on CPAP asap with a PEEP of no less than 5. If possible transfer from labour ward with Neopuff mask sealed on baby’s face, maintaining a PEEP of at least 5. (Consider in bigger babies with respiratory distress that give the impression of prematurity or infants of a diabetic mom). The longer a baby with surfactant deficiency is without PEEP or surfactant, the more hyaline membranes will develop (resulting in more damage to the alveoli). Therefore it will take the baby longer to clear the debris and come off CPAP or nasal prong oxygen. Wean FiO2 by 0.1 (10%) at saturations of 95% or more every 3 minutes until baby is on FiO2 of 0.21 with saturations >88%.

SURFACTANT REPLACEMENT

Indications

Premature baby with HMD. If you are unable to wean the baby to FiO2 < 0.35 within 2 hrs of life, give surfactant therapy. Best practice is to have a CXR in all babies with respiratory distress to exclude pathology other than HMD (eg pneumothorax), but if CXR will delay surfactant administration significantly, postpone CXR. Do not give surfactant in a baby <800g or < 27 gestation (offer CPAP only) or if baby has abnormalities incompatible with life. Surfactant not for use during resuscitation. Discuss with paediatric consultant on call should there be any doubt since there are always exceptions to the rule.

Drug

Preferably use Survanta in babies >1.2kg and Curosurf in babies <1.2kg. (If only one brand is available, use the one available).

Dose

Survanta 100mg/kg (4ml/kg). Curosurf: use dosing chart or 100-200mg/kg. Make sure the surfactant is warmed to room temperature before administration.

Method

Use an ETT with side port or an ETT with NGT cut to the same length as the ETT. Optional: give atropine 0.02mg/kg IVI before intubation. Intubation must be an aseptic procedure. Intubate orally/nasally with black marker on ETT just disappearing between the vocal cords. Check for equal air entry bilaterally. (To confirms that ETT is not in one of the bronchi and surfactant administration will be to both lungs.)
Administer the surfactant as a slow push via side port or NGT. Give +-2ml air bolus afterwards to clear all the surfactant from the side port/NGT into the lung. No positioning of the body is needed. Neopuff only if baby has sats < 88%. If the baby is breathing, extubate and place on CPAP immediately. Document time of administration. Do not suction the airways for 6 hours after surfactant administration if possible.
Wean Fi02 as per instructions above. If FiO2 not 0.35 or less within 2 hours after administration, intubate and transfer to NICU.
Reassess baby 6 hours after administration. If FiO2 requirements again increased to > 0.35, administer second dose of surfactant and consider transfer to TBH (ventilated).
Mechanical ventilation and transfer to NICU is indicated for recurrent or severe apnoea (apnoea needing more than just stimulation to revive baby). Consider blood gas, intubation and NICU in babies with severe sternal/intercostal recession (severe increased work of breathing) despite surfactant administration irrespective of current FiO2 requirement.

MECONIUM ASPIRATION SYNDROME

Ideally if severe meconium aspiration syndrome is confirmed on CXR a meconium lavage should be done at TBH. If the baby is too unstable for transport, give a stat dose of Survanta 6ml/kg.

Carefully watch for PPHN. Treat PPHN aggressively.

PERSISTENT PULMONARY HYPERTENSION OF THE NEWBORN (PPHN)

Definition

Persistence of high pulmonary vascular resistance, therefore pulmonary blood pressure with resultant cyanosis due to right to left shunting across the PDA and/or foramen ovale. It may be associated with perinatal asphyxia, MAS, congenital pneumonia, RDS, congenital diaphragmatic hernia and pulmonary hypoplasia.

Diagnosis

Suspect it if there is cyanosis or low sats on supplemental oxygen with or without respiratory distress. Confirm there is a transcutaneous oxygen saturation gradient >10% between the right arm (preductal [higher sats]) and that from the lower limbs (postductal) circulation (or paO2 gradient > 2.7kPa). Diagnosis confirmed on echocardiogram.

Management

Oxygen is a very potent pulmonary vasculature dilator. Give the highest possible FiO2 to keep preductal sats at least 85% but preferably >95%. If mechanical ventilation is needed to achieve this, aim for pH>7.25, PaCO2 4.5-6kPa, PaO2 6-10kPa. Avoid hyperventilation with pCO2 < 4kPa as this may decrease cerebral perfusion. Consider transfer for HFOV+-nitric oxide+-sildenafil.
Normal saline bolus 20ml/kg then consider inotropes to maintain mean arterial pressure around 50mmHg. May need to increase maintenance fluids to 100-120ml/kg/day. (Choice of inotropes depends on suspected cause, e.g. Sepsis: dopamine/dobutamine plus adrenalin. Asphyxia: dobutamine. Unknown: dopamine)
Refractory hypotension may need hydrocortisone 1mg/kg 6hrly IVI/IMI (stress dose).
Ensure minimal handling and sedate infant. (morphine and midazolam if normotensive, fentanyl and midazolam if hypotensive). Try to avoid muscle relaxants unless absolutely necessary.
If PPHN is secondary to MAS/RDS, administer surfactant
If unable to maintain sats >80%, try to get pH >7.45 by giving a bicarbonate bolus (2ml/kg of 8,5% solution). Consider a bicarbonate infusion.
When alkalinising infants, ensure that normal Ca values are maintained on blood gasses as hypoCa decreases cardiac contractility.
Be aware that hypocarbia and alkalosis have been associated with hearing loss in infants surviving PPHN and should therefore be reserved for refractory cases.
Wean infants very cautiously once improvement is noted.

CHRONIC LUNG DISEASE (CLD)/BRONCHOPULMONARY DYSPLASIA (BPD)

CLD predominantly affects preterm babies who have needed mechanical ventilation on O2 therapy. It can also occur in term infants who needed aggressive ventilator therapy for severe lung disease. The development of CLD is often suspected when mechanical ventilation or oxygen dependence extend beyond 10-14 days. Definitive CXR features of CLD often do not develop until later in the course (usually 3-4weeks of life). Definition: CXR with evidence of CLD plus:

GA at birth	Mild	Moderate	Severe
≤32 weeks	Supplemental O₂ for 28 days and in room air at 36wks CGA or at discharge	Supplemental O₂ for 28 days and FiO2 <0.3 at 36 weeks CGA or at discharge	Supplemental O₂ for 28 days and FiO₂≥0.3 at 36 weeks CGA or at discharge
>32 weeks	Supplemental O₂ for 28 days and room air by postnatal D56 or at discharge	Supplemental O₂ for 28 days and FiO₂ <0.3 by postnatal D56 or at discharge	Supplemental O₂ for 28 days and FiO₂ ≥0.3 by postnatal D56 or at discharge

Prevention

Limit O₂ duration and concentration
CPAP rather than ventilation where possible
Avoid excessive fluid administration in the first week
Treat PDA once diagnosed and needing FiO₂> room air
Use methylxanthines eg caffeine/aminophylline

Treatment

Maintain fluids at 130-150ml/kg/day in order to supply sufficient calories for growth but avoid pulmonary oedema
Supplement nutrition 120-150kcal/day to gain weight at 15-20g/kg/d (dietician consultation).
Consider 5-7 day course of diuretics. HCTZ 1mg/kg/dose 12hrly and spironolactone 1mg/kg/dose 12hrly. Monitor electrolytes while on diuretics. Chronis use of diuretics is associated with complications. Never discharge a patient on diuretics.
Steroids: There is evidence that steroid therapy is associated with a reduction in days on the ventilator. Potential side effects include hyperglycaemia, hypertension, GIT perforation, cardiomyopathy, failure to gain weight and abnormal neurodevelopmental outcome. Decision to use steroids must be made by consultant. Consider use of steroids at D7-14 if the infant is still ventilator dependent and CXR is suggestive of development of CLD.
Bronchospasm: nebulised salbutamol 0.5-1mg/kg/dose 2-6 hrly. (Bronchospasm may not manifest as audible wheezing. A trial of of bronchodilators can be used and the infant assessed for decreased work of breathing after treatment. Bronchial reactivity may be increased secondary to infection (especially viral). Therefore consider investigating in infants whose respiratory function deteriorates.
If not ventilated, wean O₂ accepting sats of 86-93%.
If unable to wean, look for signs of cor pulmonale or a PDA, do ECG and consult cardiologist.
Keep Hb >12g/dl if ventilated and >10g/dl if on O₂ only. If packed cells are needed, infuse furosemide 1-2mg/kg half way through the transfusion.
Infant can be discharged on home oxygen if infant >2000g, gaining weight on full oral feeds and has a good social background.
Immunisation: consider RSV prophylaxis and Influenza vaccine from 6 months of age.

Neonate with Respiratory Distress

Drugs mentioned