Hypertension and Surgery

1. Hypertension and Surgery
Dr. Basit

2. • the most common medical reason for postponing surgery
• well known to be a risk factor for cardiovascular catastrophe
• Sympathetic activation during the induction of anesthesia can
cause the blood pressure to rise by 20 to 30 mmHg and the heart
rate to increase by 15 to 20/min in normotensive individuals
• These responses may be more pronounced in patients with
untreated hypertension in whom the systolic blood pressure can
increase by 90 mmHg and heart rate by 40/min.

3. • Patients with preexisting hypertension are more likely to
experience intraoperative blood pressure lability, which may lead
to myocardial ischemia.
• Blood pressure and heart rate slowly increase as patients recover
from the effects of anesthesia during the immediate postoperative
period.

4. PERIOPERATIVE RISKS ASSOCIATED WITH
HYPERTENSION

5. • The level of risk is dependent upon the severity of hypertension.
• cardiovascular responses that potentially increase the risk of
surgery
• diastolic hdysfunction
• systolic dysfunction
• renal impairment
• cerebrovascular and coronary occlusive disease

6. Severe hypertension
• patients with untreated severe hypertension (mean systolic and
diastolic pressure of 211 and 105 mmHg, respectively) have
exaggerated hypotensive responses to the induction of anesthesia
and marked hypertensive responses to noxious stimuli

7. Mild to moderate hypertension
• Patients with less marked hypertension (diastolic pressure less
than 110 mmHg) do not appear to be at increased operative risk.
• when hypertension has caused end-organ disease such as
congestive heart failure and renal insufficiency, the probability of
adverse cardiac outcome in the perioperative period increases
significantly

8. Secondary hypertension
• Patients with suspected secondary hypertension ideally should
undergo a diagnostic evaluation prior to elective surgery.
• most patients are not at increased perioperative risk as long as
the hypertension is not severe and serum electrolytes and renal
function are normal.

9. MANAGEMENT OF PATIENTS ON CHRONIC
ANTIHYPERTENSIVE THERAPY
Oral antihypertensive medications should be
continued up to the time of surgery.

10. Safety of antihypertensive drugs
preoperatively
• Diuretics
• ACE/ARB
• Ca channel blockers
• Centrally acting sympatholytic drugs
• Beta blockers

11. POSTOPERATIVE HYPERTENSION
A history of hypertension preoperatively is the
most important risk factor for postoperative
hypertension

12. Indications for therapy
• Any patient who experiences a marked rise in blood pressure following
surgery should be treated immediately.
• Remedial causes of hypertension such as pain, agitation, hypercarbia,
hypoxia, hypervolemia, and bladder distention should be excluded or
treated.
• Patients on chronic antihypertensive therapy should resume their usual
medications postoperatively as needed.
• Therapy should be considered for patients with a sustained systolic blood
pressure above 180 mmHg or diastolic blood pressure greater than 110
mmHg, once remedial causes have been excluded or treated.

13. Choice of drugs
• With the exception of beta blockers and clonidine, it is not necessary for
patients receiving chronic antihypertensive therapy who are unable to
resume oral medications to continue the same class of drugs
postoperatively
• Patients taking diuretics may be given
parenteral furosemide or bumetanide
• Patients taking an ACE inhibitor may be given parenteral enalaprilat.
• Patients taking centrally acting agents can be given a clonidine patch.
• Patients taking calcium channel blockers can be given
intravenous nicardipine.