HTN Flashcards
Definition of HTN
BP > 140/90 on at least two occasions
Reading should be measured at least 1-2 weeks apart
__% of adults in the US have HTN
24%
Two types of HTN
1) Essential (95% of cases)
- Unknown cause (idiopathic)
- Strong genetic link (maybe related to inherited biochemical abnormalities)
- Associated with drinking, smoking, and OSA
2) Secondary (5% of cases)
- HTN with a known cause
- Renal problems is main cause
- Also endocrine, pregnancy, neurologic, drug induced, and OSA
Treatment for essential HTN
1) Lifestyle Modification
- Recommended for those without CV disease or end organ damage
2) Drug therapy
- Used in combo with lifestyle modification
- Drug therapy recommended for those with other existing comorbidities (DM, high cholesterol, angina, smoking) and/or have evidence of end-organ damage
Lifestyle modification involved for treating HTN
Weight loss Decrease ETOH intake Exercise Stop smoking Consume enough calcium and potassium Eat less sodium
Treatment of Secondary HTN
1) Treat the cause
- Usually d/t renal artery stenosis (kidneys perceive this as decreased blood flow and activate the RAAS) or primary aldosteronism
- So usually, require surgery
2) Drug therapy if not a candidate for surgery
Anesthesia considerations for patients on beta blockers
Rebound SNS stimulation (d/t upregulation of receptors)
Avoid in BBs in asthmatics, COPD, CHF, HB, Sick Sinus
Continue BB therapy
Anesthesia considerations for patients on methyldopa
A2 agonist used to treat HTN
Can cause rebound HTN and will decrease anesthetic requirements
Anesthesia considerations for patients on clonidine
A2 agonist
Rebound HTN and decrease in anesthetic requirements
Anesthesia considerations for patients on prazosin
A1 blocker
Compensatory vasoconstriction is blocked, so there may be an exaggerated drop in BP during spinal/epidural block
Anesthesia considerations for patients on hydralazine
Causes potassium influx and hyperpolarization
May cause angina in those with ischemic heart disease
Anesthesia considerations for patients on ACE inhibitors (prils)
Drop in BP and hemodynamic instability. This is one of the few meds that we may tell people to hold. Remember these people will be very dry.
Anesthesia considerations for patients on Angiotensin II blockers (artans)
BP drop with induction
Definition of hypertensive crisis
Acute DBP > 130
What can a hypertensive crisis cause?
Encephalopathy
SAH
CHF
Renal insufficiency
How to treat hypertensive crisis?
Goal is to treat promptly, but gradually. Monitor BP reduction with an a-line.
- Decrease MAP by 20% during first 2 hours
- Gradually reduce BP to normal over the next 24-48 hours
- Achieve this with NTG or nipride** (use foley to measure UO, want to make sure the kidneys are still able to perfuse. Remember they are very sensitive to drops in BP! They can’t really autoregulate below a MAP of 80)
Specific meds we can use to treat a hypertensive crisis
Place an a-line to closely monitor our reduction in BP!!
Nitroprusside 0.5-10 mcg/kg/min
- Drug of choice** (short DOA)
NTG 5-200 mcg/min
Labetalol 40-80mg Q 10 min
Esmolol 50-300 mcg/kg/min
If you have a patient with HTN, you are wondering about these these
Do they keep their HTN under control?
What’s their drug regimen?
Do they have any evidence of end-organ damage? (Angina, CHF, Renal insufficiency, CVA, PVD, etc)
Goals on induction for pts with HTN
Minimize SNS stimulation on DVL
- Do so with additional narcotic, lidocaine (topical or IV), and by increasing volatile agent
Lidocaine IV 1-1.5mg/kg
Lidocaine Topical 5cc of 2-4%
Goals during maintenance for pts with HTN
It is common for patients with HTN to have wide hemodynamic shifts. Our goal, therefore, is to adjust anesthetic depth in a way that minimizes hemodynamic shifts. How the fuck do we do that?
- Choose an IA that can be easily adjusted (low BG coefficient like desflurane)
- Use a balanced technique like the pros
- Have phenylephrine and ephedrine available
- Consider neo gtt if unable to get adequate depth of anesthesia
Post-op goals for pts with HTN
Minimize SNS stimulation from pain and N/V
This induction agent is inappropriate for those with HTN
Ketamine
How to treat intra-operative HTN
It’s usually due to pain!!
Opioids (if d/t pain) IAs (will decrease SVR) BBs NTG SNP (hang a drip if a longer case)
Intra-op HTN is more common in patients with
Essential HTN
Do patients with HTN handle HTN or hypotension better?
HTN! It’s what they’re used to!
How to treat intra-op hypotension
- Reduce anesthetic depth (often caused by being too deep)
- Fluids
- Sympathomimetics (neo and ephedrine)
- Is their rhythm normal? If not, fix that shit.
- Make sure their CO2 is normal
Monitoring used for those with HTN
5 Lead EKG**
If the patient has ventricular dysfunction and is having extensive surgery, then get a-line, CVP, PA cath
TEE in extreme cases and you’re tryna get fancy
Goals on emergence for pts with HTN
Again we're avoiding SNS outflow We want a smooth emergence! - Opioids - Lidocaine - BBs, NTG - Deep extubation (if not a difficult airway)
As we shut the gasses off, we’ll see a rebound increase in BP. Work in the stuff above as appropriate.
How should HTN be treated post-op as long as pain is under control?
Labetalol 5-20mg IV Q 10min
Hydralazine 2.5-10 mg IV Q 10-20 min
NTG 0.5-10 mcg/kg/min if a-line present
