Merck Manual

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Outpatient Procedures


Paul K. Mohabir

, MD, Stanford University School of Medicine;

André V Coombs

, MBBS, Texas Tech University Health Sciences Center

Reviewed/Revised Nov 2020 | Modified Sep 2022
View Patient Education


The general rule is for patients to have no oral intake after midnight the night before surgery. For certain gastrointestinal procedures, cleansing enemas or oral antibiotic bowel preparations must be started 1 to 2 days before surgery. When other prophylactic antibiotics are needed before a procedure, the initial dose must be given within 1 hour before the surgical incision and discontinued within 24 hours after surgery.

Discharge precautions

Before discharge, patients should be free of severe pain and should be able to think clearly, breathe normally, drink, walk, and urinate.

If sedatives (eg, opioids, benzodiazepines) were used during an outpatient procedure, patients should not leave the hospital unaccompanied. Even after anesthetic effects have apparently worn off and patients feel fine, they are likely to be weak and have subtle residual effects that make driving inadvisable; many patients require opioids for pain. Older patients may be temporarily disoriented because of the combined effects of anesthesia and surgical stress and may develop urinary retention caused by immobility and anticholinergic drug effects.

View Patient Education
NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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