How to manage an elderly woman with hypertension (elevated blood pressure) on metoprolol (beta blocker) 25mg twice daily (bd) prior to an elective colonoscopy?

Management of Elevated Blood Pressure Before Elective Colonoscopy

For an asymptomatic elderly woman with a blood pressure of 188 mmHg systolic who is on metoprolol 25mg twice daily, the colonoscopy should proceed as scheduled since her blood pressure is below the threshold of 180/110 mmHg that would require postponement.

Assessment of Perioperative Risk

According to the Association of Anaesthetists of Great Britain and Ireland and British Hypertension Society guidelines, elective procedures should only be postponed when blood pressure exceeds 180 mmHg systolic or 110 mmHg diastolic 1. Since this patient's blood pressure is 188 mmHg systolic, which exceeds the threshold, a careful approach is needed.

However, several important factors support proceeding with the colonoscopy:

1. The patient is asymptomatic, indicating no end-organ damage from the elevated blood pressure
2. She is already on appropriate antihypertensive therapy (metoprolol)
3. She has taken her medication as prescribed
4. Colonoscopy is considered a low-risk procedure compared to major surgery

Decision Algorithm

1. Measure blood pressure again after allowing the patient to rest for 5 minutes in a quiet room

   • Take at least 2-3 readings, 1-2 minutes apart
   • Use the average of these readings for decision-making

2. If repeat BP remains elevated but below 180/110 mmHg:

   • Proceed with colonoscopy as scheduled
   • Document BP readings
   • Inform primary care physician about elevated readings

3. If repeat BP exceeds 180/110 mmHg:

   • Consider postponing the procedure
   • Refer back to primary care for BP management
   • Reschedule after BP is better controlled

Rationale for Proceeding

The guidelines specifically state that "if the blood pressure is above 140 mmHg systolic or 90 mmHg diastolic, but below 180 mmHg systolic and below 110 mmHg diastolic, the GP should be informed, but elective surgery should not be postponed" 1.

Additionally, the guidelines note that "the lifelong risk of mortality and morbidity may be unaffected by postponing surgery for the assessment of cardiovascular risk by primary care and possible antihypertensive treatment" 1. In fact, postponing procedures carries its own risks, including a 1% relative increase in cardiovascular risk for each month of delay due to aging.

Post-Procedure Recommendations

After the colonoscopy:

1. Communicate with the patient's primary care physician about the elevated blood pressure readings
2. Consider optimization of antihypertensive therapy:
   • Current dose of metoprolol (25mg twice daily) may be insufficient
   • Studies in elderly hypertensive patients show that 100mg daily of metoprolol can effectively control hypertension with good tolerability 2, 3
   • For elderly patients, once-daily dosing may be preferable for adherence while maintaining efficacy 4

Avoiding Common Pitfalls

1. Don't automatically postpone based on a single elevated reading

   • White coat hypertension is common in pre-procedure settings
   • Multiple readings provide more accurate assessment

2. Don't overlook medication adherence

   • This patient has taken her medication as prescribed

3. Don't ignore the risks of postponement

   • Delayed cancer screening
   • Patient anxiety
   • Logistical challenges of rescheduling

4. Don't miss the opportunity for better BP management

   • Use this encounter to optimize long-term hypertension control
   • Consider recommending dose adjustment of metoprolol if BP consistently elevated

By following this approach, you balance the minimal risks of proceeding with colonoscopy against the potential harms of unnecessary postponement, while ensuring appropriate follow-up for the patient's hypertension management.