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Flashcards in HTN Deck (28)
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1

Definition of HTN

  1. BP > 140/90 on at least two occasions
  2. Reading should be measured at least 1-2 weeks apart
  • Prehypertension:  120-130/80-89
  • Stage 1 HTN: 140-159/90-99
  • Stage 2 HN: ≥160/≥100

2

Two types of HTN

  1. Essential - Unknown etiology (idiopathic)
    • 95% of cases 
    • Strong genetic link (maybe related to inherited biochemical abnormalities)
    • Possible Naimbalences
    • Associated with drinking, smoking, and OSA
  2. Secondary -  Know etiology 
    • 5% of cases
    • Renal problems is main cause
    • Also due to endocrinepregnancy, neurologic, drug induced, and OSA

3

Treatment for essential HTN

  1. Lifestyle Modification
    • Recommended for those without CV disease or end organ damage (Decrease Na intake, take in enough K and Ca exercise, lose weight, stop smokin and drinkin)
  2. 2nd line treatment: Drug therapy ​​(with lifestyle mod) 
    • Stage I: diuretic - 1st line
    • Stage II: dual therapy
    • Stage III: continue adding
    • Diabetic: ACE-I are 1st line drugs

4

Treatment of Secondary HTN

Treat the cause

  1. Often times surgical
    • pheochromocytoma- adrenalectomy
    • renal artery stenosis/primary aldosteronism- angioplasty (HTN d/t activation of RASS because kidneys perceive decreased blood flow
  2.  Drug therapy if not a candidate for surgery

5

Anesthesia considerations for patients on ß-blockers. Who should they be avoided in?

  • Patients who are on them should be take them the  morning of surgery to prevent rebound SNS stimulation
  • Rebound SNS stimulation is d/t upregulation of receptors
  • AVOID in ß-blockers
    • Asthmatics
    • COPD
    • CHF
    • HB
    • Sick Sinus Syndrome 

6

Anesthesia considerations for patients on Methyldopa and Clonidine?

  1. A2 agonist used to treat HTN
  2. Can cause rebound HTN
  3. Will DECREASE anesthetic requirements

7

Anesthesia considerations for patients on Prazosin

  1. A1 blocker
  2. Compensatory vasoconstriction is blocked
    • there may be an exaggerated drop in BP during spinal/epidural block

8

Anesthesia considerations for patients on Hydralazine

  1. Causes potassium influx and hyperpolarization
  2. May cause angina in those with ischemic heart disease (not sure the mechanism of action)

9

Anesthesia considerations for patients on ACE inhibitors 

  1. They are the 'prils
  2. Associated with drop in BP and hemodynamic instability.
  3. tell patients to HOLD THE MORNING OF SURGERY (24-48 hours)
  4. If they take it they will have very labile blood pressures!!!
  5. may not respond to phenylephrine of ephedrine - use vasopressin

(BP regulated by three systems - GA knocks out the autonomic, ACE-I take out the RAAS and that leaves the vasopressin system left →they are very likely to be volume dependent (if they take their meds). Hypotension responsive to fluid and sympathomimethic drugs- if they are resistant ususally vasopressin or a vasopressin analough will do the trick!)

10

Anesthesia considerations for patients on Angiotensin II blockers 

  1. 'Artans
  2. Drop in BP with induction 

(Patients who take ARBS may be refracitve to convetional vasoconstrictors like phenylephrine and ephedrine → may need to use vasopressin or vasopressin analogue)

11

Definition of hypertensive crisis

  • Acute DBP > 130 mmHg

                        or  

  • parturient with a DBP> 109 mmHg

12

What can a hypertensive crisis cause?

  1. Encephalopathy
  2. SAH (Subarachnoid Hemorrhage)
  3. CHF
  4. Renal insufficiency

13

How is a hypertensive crisis treated?

 

  1. Goal is to lower BP promptly, but gradually.
  2. Monitor BP reduction with an a-line. and end organ profusion with a foley 
    • Decrease MAP by 20% during first 2 hours 
    • Then even more gradually reduce BP over the next 24-48 hours (160/110 - if no signs of end organ ischemia)
  3. Pharmacologic interventions include
    • Sodium Nitroprusside (Nipride): 0.5-10.0 mcg/kg/min
      • Immediaate onset and short DOA
      • DRUG OF CHOICE
    • Nicardipine (dihydropiridine CCB) - says Stoelting
    • NTG: 5-200 mcg/min
    • Labetolol: 40 - 80 mg q 20 min
    • Esomolol: 50-300 mcg/kg/min

14

The preoperative evaluation of a person with essential hyperteshion should elicit which things?

  1. The adequacy of BP controll
    1. Is it controlled or uncontrolled?
      • a DBP of 110-115 should have surgery postponed
    2. What is their normal Blood Pressure
    3. What is their medication therapy?
    4. Do they have evidence of end-organ damage?
      • AnginaCHF, LV hypertrophy
      • Renal insufficiency
      • CVA
      • Peripehral Vascular Disease

15

Anesthetic management of INDUCTION for patients with HTN 

  1. Minimize SNS stimulation on DVL and intubation  (they often have exagerated HTN with this and tachycardia and HTN is a risk for ISCHEMIA) 
  2. What to do? 
    1. Increasing volatile agent
    2. Give Esmolol prior to DVL: 10-20 mg
    3. additional opioids 
    4. Lidocaine
      • IV: 1-1.5 mg/kg
      • LTA: 5cc of 2-4%
  3. ​​​​ Efficient DVL: <15 sec
  4. NO KETAMINE!!!

16

Management of MAINTINENCE of anesthesia for patients with HTN

GOAL = to adjust anesthetic depth to minimize wide shifts in hemodynamics

(It is common for patients with HTN to have wide hemodynamic shifts) 

  1. Chose a VA that is easily and quickly titrated
    • Low BG coefficient→ des (0.42) or sevo (0.69) - low solubility
    • +/- iso (1.4)
  2. Rely on multiple agents! = better total coverage 
    • Use a balanced technique(N2O, opioids, versed)
  3. Have phenylephrine and ephedrine readily available -
    • Consider neo gtt if unable to get adequate depth of anesthesia (i dont get this, but it is in the notes)

17

Post-op goals for pts with HTN

Minimize SNS stimulation from pain and N/V

opioids, anti-nausea

18

What are the blood gas coeficients of the volitile agents?

 

  • Nitrous Oxide: 0.47
  • Desflurane: 0.42
  • Sevoflurane: 0.69
  • Isoflurane: 1.4
  • Enflurane: 1.8
  • Halothane: 2.3

19

Treatment of intraoperative HYPERtension

  1. It's usually due to pain!! →Opioids (if d/t pain)
  2. Increase volitile anesthetics →will decrease SVR 
  3. ß-Blockers
  4. NTG and SNP (Nipride) →hang a drip for a longer case or need sustained controll 

20

Treatment of intraoperative HYPOtension

  1. Reduce anesthetic depthoften caused by being too deep
  2. Fluids
  3. Sympathomimetics (neosinephrine and ephedrine)
  4. Is their rhythm normal? →They may be in a Junctional
    1. Ephedrine is a good choice →will bring up HR
    2. Maintain Normocapnea→ HTN in patients with hypercarbia →increases heartrate and BP
    3. If the rhythm is not normal → AVOID high concentrations of IAs 

21

Bonus ****

What is premissive hypercapnea?

Allowing the PaCO2 to increase up to 55mmHg spontaneously breathing patients to avoid or delay the need for endotracheal intubation

 

22

Monitoring used for those with HTN

  1. 5 Lead EKG
  2. If the patient has ventricular dysfunction and is having extensive surgery
    • →then get a-line, CVP, and/or PA cath
  3. may want to use a TEE in extreme cases

23

Anesthesia management of emergence in a patient with HTN

Goal = Nice smooth controlled emergence → these patients will have exagerated responses → if they had labile pressures durring the surgery they will likely have labile pressures at emergence

  1. Minimize SNS outflow! When the gasses start to come off the patient will begin to become hypertensive → be ready to treat or pre-treat as anticipated
    • Opioids  
    • Lidocaine
    • ß-blockers (esmolol, labetolol)
    • NTG
  2. Deep extubation (if not a difficult airway) →avoids the SNS stimulation of being awake with the ETT

24

Treatment of potoperative HTN

  1. If pain is adequately controlled→prompt treament is necessitated to decrease the risk of myocardial ischemia, stroke, dysrhythmias and CHF
  2. Treat with: 
    • Labetalol:  5-20 mg IV Q 10 min (ß1 and ß2)
    • Hydralazine: 2.5-10 mg IV Q 10-20 min (arterial > venous)
    • Sodium Nitroprusside0.5-10 mcg/kg/min if  an a-line is present

25

How to treat a intraop junctional rhythm

  1. decrease anesthetic depth
  2. maintain normocapnea

(junctional rhythm in a healthy patient is directly realted to anesthetic depth)

26

Pulmonary arterial HTN

  • PAP (mean pulmonary artery pressure) > 25 mm Hg at rest or
  • PAP (mean pulmonary artery pressure) > 30 mm Hg with exercise

&

  • PAOP (pulmonary artery occlusion pressure) =
  • PVR (pulmonary vascular resistance) > 3 Wood units (mm Hg/L/min) - normal 0.2-1.6 woods or 20-130 dyn

27

Pulm artery HTN treatment

  1. Oxygen, Anticoagulation, and Diuretics
  2. Calcium Channel Blockers
    • Nifedipine, diltiazem, and amlodipine
  3. Phosphodiesterase inhibitors
    • dilate pulmonary blood vessels and improve cardiac output
  4. Nitric oxide (NO)
    • improves V˙ /Q˙ matching and improves oxygenation by relaxing pulmonary vascular smooth muscle
  5. Prostacyclins
    • epoprostenol, treprostinil, iloprost
    • are systemic and pulmonary vasodilators that also have antiplatelet activity.
  6. Endothelin Receptor Antagonists
    • Bosentan

28

Pulm artery HTN anesthtetic 

  • Hypoxia, hypercarbia, and acidosis must be aggressively controlled  
    • they cause increased PVR
  • avoid ketamine & etomidate 
    • may inhibit pulmonary vasorelaxation
  • monitor CVP and intra-arterial BP
  • maintenance with IA
    • Systemic hypotension can be corrected with fluids, phenylephrine, or more potent vasoconstrictors if needed