Heart failure in neonates

P29.0

DESCRIPTION

Clinical syndrome reflecting the inability of the myocardium to meet the oxygen, nutritional or metabolic requirements of the body. Heart failure may be acute or chronic.

The main causes of heart failure are:

  • Congenital heart abnormalities:
    • Left-sided outflow obstruction, e.g. interrupted aortic arch, co-arctation of the aorta and aortic valve stenosis.
    • Left to right shunts, VSD and PDA.
    • Hypoplastic left heart.
    • Complex congenital heart lesions.
  • Acquired conditions:
    • fluid overload,
    • sepsis,
    • hypoglycaemia,
    • hypoxia,
    • acidosis,
    • severe anaemia,
    • dysrhythmias,
    • cardiomyopathy,
    • pneumopericardium,
    • hyperthyroidism,
    • hypertension.

DIAGNOSTIC CRITERIA

Diagnosis relies on history, physical examination and a chest X-ray.

Clinical

  • Acute heart failure may present with shock, i.e. cardiogenic shock.
  • Heart failure is usually associated with fluid retention and congestion.
  • History of recent onset of:
    • poor feeding,
    • tachypnoea (> 60 breaths/minute),
    • sweating, and
    • poor or excessive weight gain in excess of 30 g/24 hours.
  • Physical findings:
    • tachycardia (> 180 beats/minute),
    • gallop rhythm (with/without a cardiac murmur),
    • cardiomegaly,
    • features of cardiogenic shock, i.e. cold wet skin, weak pulses, hypotension,
    • reduced urinary output,
    • pulmonary venous congestion and fluid retention,
    • systemic venous congestion,
    • hepatomegaly, and
    • signs and symptoms of underlying condition/disease.
  • Always check the femoral pulses.

Special Investigations

  • Radiology: cardiomegaly is usually present, cardiothoracic ratio > 60%. Caution - thymic shadow may be present.
  • Electrocardiogram may show evidence of hypertrophy of one or more heart chambers and/or dysrhythmias.
  • Echocardiography may show a reduced ejection fraction or shortening fraction of left ventricle.

GENERAL AND SUPPORTIVE MEASURES

  • Nurse in a neutral thermal environment.
  • Restrict fluids, but ensure adequate nutrition.
    • Administer 75% of estimated daily fluid requirements.
    • Use breast milk or low-salt milk formulae.
    • Tube feeding.
  • Treat the underlying condition, e.g. sepsis and cardiac tamponade.

MEDICINE TREATMENT

First treat shock, if present.

To prevent hypoxia:

  • Oxygen via face mask, nasal cannula or head box.

Combination medicine therapy is usually indicated,


Afterload reduction: ACE inhibitor or vasodilator

Monitor blood potassium levels and stop potassium supplements while patient is on an ACE inhibitor.
ACE inhibitors are contraindicated in renal failure, bilateral renal artery stenosis or a single functioning kidney.

Consider ACE inhibitors in persistent heart failure where left sided outflow obstruction has been excluded, other measures have failed and only after consultation with a paediatrician or paediatric cardiologist.

  • Captopril, oral, 0.01–0.05 mg/kg/dose, 8–12 hourly, initially.
    • Adjust dose and interval based on response.
    • Administer 1 hour before feeding.
    • Continue as long as needed to control the heart failure

Diuretics

Continue diuretic therapy as long as needed to control heart failure.
Monitor blood potassium levels.

Potassium supplements may be necessary if furosemide is used without spironolactone.
Hypokalaemia and hypochloraemic alkalosis may increase digitalis toxicity.

  • Furosemide, IV/oral, 1–3 mg/kg/24 hours as a single daily dose, or in 4 divided oral doses.

WITH/ WITHOUT

  • Spironolactone, oral, 1–3 mg/kg/dose, once daily.

Inotropic support

May help to stabilise patients with severe myocardial dysfunction, hypotension or low cardiac output.
May be lifesaving in severe myocarditis or cardiogenic shock.

  • Dobutamine, IV infusion, 2.5–15 mcg/kg/minute.
    • Continue until myocardial function and blood pressure improve.
    • Ensure normovolaemia.
    • Monitor blood pressure.

Acute left-heart failure: acute pulmonary oedema or pulmonary venous congestion

  • Oxygen 100%, via nasal cannula.
  • Furosemide, IV, 1–3 mg/kg, immediately.

For patients not responding to furosemide:

  • Morphine, IV, 0.1 mg/kg.
  • Inotropic support, as above.
  • Afterload reduction, as above.

To raise the alveolar pressure above pulmonary capillary pressure, intubate with intermittent positive ventilation.
Titrate oxygen according to saturation, 90–94%.

SURGICAL TREATMENT

Palliative or corrective surgery for certain congenital heart lesions.

REFERRAL

  • Deterioration despite adequate treatment.
  • For determination of the underlying cause, and initiation of specialised, after stabilisation.