A patient with CHD may present with collapse and shock, which is defined as an acute state where the circulation is inadequate to meet the metabolic demands of tissues.
However, other cardiac conditions (e.g. cardiomyopathies, arrhythmias, pericardial effusion, etc.) may also present in a shocked state. There are also many non-cardiac causes of shock (e.g. sepsis, anaphylaxis, inborn errors of metabolism) which must be considered in the differential diagnosis of shock and metabolic acidosis.
Collapse and/or shock due to structural heart disease is usually associated with left-sided obstructive lesions that result in inadequate systemic blood flow (e.g. aortic stenosis, coarctation of aorta).
Specific features of shock include:
- Reduced spontaneous movements
- Mottled skin
- Prolonged capillary refill time
- Decreased pulses or narrow pulse pressure
- Hypothermia and widening of toe-core temperature difference
- Tachycardia
- Tachypnoea and respiratory distress
- Hypotension
- Oliguria/ anuria
- Lactic acidosis
Management
General principles
General principles of resuscitation are essential; airway, breathing then circulation. Maintain adequate inspired oxygenation, regardless of the cause.
There is often a concern that oxygen administration may be dangerous, (e.g. might close a life-sustaining ductus). In general resuscitation, this is highly unlikely and standard resuscitation interventions should be used first. Once the cause of collapse is known, this may then be modified.
Management of the neonate
- Strongly consider commencing a prostaglandin infusion even before a diagnosis has been made.
- Starting dose of PGE2 is typically 0.05 – 0.1 mcg/kg/minute
- Monitor for apnoea
- Consider volume expansion, but only repeat if there is an improvement
- Volume expansion
- Judicious fluid administration: Only administer fluid if there is good evidence of hypovolemia
- Follow local policy on whether to use colloid or crystalloid but consider:
- Plasma expander (e.g. 4.5% Human Albumin Solution) 5 ml/kg
- Normal Saline 10 ml/kg
- Packed red cells 5 ml/kg if there is evidence of recent blood loss or PCV <0.35
- Give fluid volume cautiously in increments over 30 minutes
- Larger boluses may be required for rapid intravascular expansion in hypovolemic patients
- Discuss with a pediatric cardiologist early
- Consider Invasive BP monitoring (always be aware of possibility of coarctation)
- Consider CVP monitoring
- Correct metabolic acidosis
- Consider inotropes if there is:
- Large heart on chest radiograph
- No improvement with fluid bolus
- Catecholamines (adrenaline, noradrenaline, dopamine, dobutamine)
- Phosphodiesterase inhibitors (milrinone, enoximone) rarely used in the emergency situation
- Use markers of tissue perfusion to decide threshold for intervention
- Assess effects of intervention using HR, BP, acid base status and perfusion
Non-cardiac causes of collapse and shock in the infant:
The table below outlines the management you should always consider when a sick collapsed baby presents to the ED.
Learning Bite
Do not forget non-cardiac causes of shock in a patient with CHD, especially sepsis.