Patient Assessment and Monitoring
Assessment priorities
Use airway, breathing, circulation first, then procedure-specific focus. Obtain baseline full vital signs and a focused history: anticoagulants, allergies (especially latex and sedatives), sleep apnea, prior reactions, and last oral intake. During sedation, continuous pulse oximetry and capnography plus intermittent blood pressure are expected; vital signs at least every 5 minutes intraprocedurally and every 15 minutes in recovery are standard.
Abdominal assessment technique
Inspect, auscultate, percuss, then palpate - auscultate before palpation so you do not alter bowel sounds. Note distension, rigidity, rebound tenderness, and absent bowel sounds; these flag perforation or ileus. Pain out of proportion to the examination is a red flag.
Recognizing complications early
Capnography detects hypoventilation and apnea before SpO2 falls; a rising ETCO2 or loss of waveform precedes desaturation. Hypotension with bradycardia during colonoscopy is the classic vagal response to colonic distension - stop insufflation, reposition, give fluids, and anticipate atropine if it persists. Post-ERCP pain with fever is pancreatitis, not "trapped gas." Tachycardia with falling blood pressure and a rigid abdomen suggests perforation.
Traps
Do not rely on SpO2 alone; supplemental oxygen can mask hypoventilation while CO2 climbs. Do not attribute post-procedure abdominal pain to insufflation without reassessing vital signs and the abdomen. Orthostatic vitals require lying-to-standing measurement and reflect volume loss, not merely age.
Worked example
During colonoscopy a patient becomes diaphoretic with HR 48 and BP 84/50. Reasoning: bradycardia plus hypotension equals a vagal response. Actions: stop the procedure and insufflation, place supine or Trendelenburg, give an IV fluid bolus, monitor; if no response, anticipate atropine.
Rule of thumb
Treat the trend, not the single number: two consecutive abnormal readings warrant action.