Hypertension

It affects about 60 million people in the US, and nearly 2/3 above 65 have HTN

Essential/primary HTN 95% of all cases

Remedial/secondary HTN has an identifiable cause and is possibly treatable (e.g., pheochromocytoma, coarctation of the aorta, renal artery stenosis, renal disease, primary aldosteronism (Conn disease)

HTN accelerates and exacerbates the onset of atherosclerotic changes in the arterial vessels of the target organs

HTN is the primary risk factor for coronary artery disease, stroke, and renal failure

HTN is a significant cause of CHF and cardiomyopathy related to increased afterload (chronic vasoconstriction)

Classifications

Anesthetic considerations

Keep BP +/- 20% of the baseline MAP

Pre-medicate to reduce anxiety

Lab studies as indicated (pt on diuretics) EKG, CXR, BMP

Continue antihypertensive on the day of surgery except diuretics

Patients may be intravascular depleted and/or have less response to sympathomimetics

Hypovolemic due to renal compensation mechanisms (high BP will lead to decreased levels of ADH and secretion of water), vasoconstriction, or diuretics

Anticipate hypertensive response to laryngoscopy, limit duration of DL to < 15 seconds

Administer fentanyl (2-3 mcg/kg) just before anticipated induction to blunt response to DL

Consider lidocaine 1 mg/kg IV one minute before induction to attenuate systemic responses

Adequate hydration before induction may help prevent postinduction hypotension

Monitor for myocardial ischemia (lead V5)

Minimize wide fluctuations of SBP during maintenance

SLOW induction with known hypertension

Administration of volatile anesthetics allows for rapid adjustment of the depth of anesthesia in response to changes in SBP.

Invasive monitoring may be helpful if extensive surgery is planned and there is evidence of LV dysfunction

Treat elevations with

• Esmolol 0.25-0.5mg/kg
• Labetalol 5 mg
• Hydralazine 5-20mg
• Nitroglycerin IV
• Cardene