Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
1
Is any of this happening now?
Call 911
HLHS in an undiagnosed or untreated newborn is an emergency.
Call emergency services if a baby:
Becomes blue, gray, very pale, limp, or difficult to wake
Has severe breathing difficulty, pauses in breathing, or grunting
Cannot feed because of breathlessness or weakness
Has cold, mottled skin with a weak response
Collapses or becomes unresponsive
For a child already receiving HLHS care, follow the cardiac team's emergency plan.
Do not delay emergency care while waiting for a routine appointment.
And for anyone, someone who:
has chest pain, tightness or pressure lasting more than a few minutes
Other emergency signs, for anyone
Someone who is struggling to breathe, gasping, choking, or cannot get words out
Someone who has sudden weakness or drooping on one side of the face or body, slurred speech, or sudden confusion
Someone who is unconscious, or cannot be woken
Someone who is bleeding heavily and it will not stop with firm pressure
Someone who has had a seizure that will not stop, or does not wake up afterwards
Someone who has lips or skin that look pale, blue, grey or blotchy
Someone who you believe has taken an overdose or swallowed something poisonous
2
Is any of this happening?
Be seen today
Seek urgent help for a clear change from the child's usual color, breathing, oxygen level, alertness, feeding, urine output, or circulation.
Contact the cardiac team promptly for less sudden changes such as worsening feeding, repeated vomiting, slower weight gain, new swelling, increasing tiredness, palpitations, reduced activity, or fever around the time of a procedure.
And for anyone, someone who:
is getting rapidly more short of breath, or has gained several pounds in a few days with swelling
3
Does any of this apply?
Book an appointment
Routine follow-up remains important when the child appears well.
Scheduled visits are used to monitor heart function, surgical pathways, growth, development, rhythm, liver health, and medicines.
Every sign above is quoted from the sofidex article on Hypoplastic left heart syndrome. If you are not sure, err upward — it is always reasonable to be checked.