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
Seek emergency care for:
Severe or rapidly worsening chest or abdominal pain
Trouble breathing, fainting, or confusion
Heavy bleeding
A swollen, painful leg with sudden breathlessness
A cold, pale, numb, or very painful limb
A rapidly worsening abdomen with severe illness
Other emergency signs, for anyone
Someone who is struggling to breathe, gasping, choking, or cannot get words out
Someone who has chest pain, tightness or pressure lasting more than a few minutes
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
Contact your surgical team promptly for increasing redness or drainage from the incision, persistent vomiting, worsening pain, fever, difficulty eating or drinking, reduced bowel function, or a new change in a dialysis fistula’s usual vibration.
The article also says
Use the discharge instructions for contact details and symptom thresholds specific to your operation.
Every sign above is quoted from the sofidex article on Anastomosis. If you are not sure, err upward — it is always reasonable to be checked.