After administering activated charcoal to a patient, what is the most critical observation to make?

The most critical observation to make after administering activated charcoal is to be alert for vomiting. This is essential because activated charcoal works by binding to toxins in the gastrointestinal tract, and if the patient vomits, there is a risk that the charcoal could be expelled, potentially reducing its effectiveness in treating the poisoning or overdose. Additionally, vomiting may pose a risk of aspiration, which can lead to serious respiratory complications.

Documenting the intervention is important for maintaining accurate medical records, but it does not provide immediate insight into how the patient is reacting to the treatment. Monitoring blood pressure is also valuable, as it can indicate the patient’s overall hemodynamic status, but it does not directly relate to the specific concerns associated with the use of activated charcoal. Calling medical control may be necessary in certain situations, but being aware of the patient's immediate condition—especially regarding vomiting—takes precedence after administering activated charcoal.