Hi,
Thanks for your question.
After going through your question, I can understand your concern.
As you have mentioned there was
internal bleeding during procedure.
The bleeding was in upper part of gastrointestinal system.
To excreted that blood has to pass through whole digestive tract.
Due to effect of different types of digestive enzymes blood turns black while excretion through stool.
Usually it took aroud 36 to 96 hours to pass any type of partical to travel from stomach (food storing bag) to
rectum and to be excreted in stool.
So you can wait for another 2 to 3 days to clear black colored stool.
For safer side repeat your
Haemoglobin level to see any significant drop in reading as compared to any postoperative reading available.
Which can help in timely detection of any active internal bleeding if present.
Hope this helps you , if so do vote as helpful.