What is hypertension?
"A sustained elevation of systemic arterial pressure"
Recommendation in JNC VII for treatment of dental patients with hypertension addressed
epinephrine in local anesthetic solutions is not contraindicated, only a minimal adverse cardiovascular response.
when general anesthetic is used with patients taking antihypertensive medications, there is a potential for wide fluctuations in blood pressure and a risk of hypotension.
Why is hypertension important?
- a. Affects 50 million Americans (2/3 of the population from ages 65-74 have high BP) and 1 billion individuals worldwide.
- b. Blood Pressure ≥140/90 mm Hg
- c. Increases with age.
- d. It can lead to pre-mature death.
- e. BP in general is an indicator of present cardiovascular fitness. The lower the BP the better (if not hemorrhaging or dehydrated)
- f. Due to this increase in morbidity it is also a predictor of mortality or early death.
Three life-shortening aspects to HT?
- 1. excess work for the heart (increase in coronary artery disease and also is associated with congestive heart failure)
- 2. strokes and cerebral infarcts
- 3. kidney injury and failure
Describe systemic pathology leading to secondary HT
1. toxemia associated with the pregnancy (preeclampsia and eclampsia)
- 2. constriction of the aorta, arteriosclerosis, kidney disease, metabolic syndrome, many
What is Essential Hypertension?
- primary hypertension or idiopathic hypertension.
- The agent that causes the initial hypertension is generally not known.
What is the early response to HT?
- initial exaggerated pressor response to stimuli response such as cold and excitement.
- over active ANS leading to smooth muscle spasms
- produces only moderate BP elevation, but can create great fluctuations in BP in individuals that are prone to HT
Describe the late response of hypertension.
- Smooth muscle of arterioles become hypertrophic
- This decreases the flow to the capillary bed and over the whole body it increases the peripheral resistance
- Blood pressure elevation becomes sustained, long-term changes will cause the baroreceptors to "re-set" to a higher BP over time.
Progression of hypertension becomes what after late response?
becomes Malignant Hypertension, goes unnoticed for years
Role of kidneys in long-term blood pressure regulation, baroreceptors?
1. Kidneys (baroreceptors) respond to rapid change to BP and are not good for long-term control due to their ability of resetting to the new arterial pressure
2. The key to regulation here is the control of fluids of the body.
Define water (pressure diuresis) and salt (pressure natriuresis).
Increased AP causes a pressure gradient that pushes water/salt out of the body.
What is the equilibirium point of the renal function curve?
where renal output is equal to water and saltintake
What is the infinite gain principle?
Arterial BP will always be returned back to the equilibrium point.
No matter how much fluid is brought in or even salt, the BP will return to an equilibrium (unless damage to kidneys or a lot of water or salt chronically)