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Monday, March 16, 2015

Congestive Heart Failure 101

CHF, Congestive Heart Failure, overview, guide, nursing school, nurse, nursing, RN, NCLEX, Cardiac, Med-Surg


Congestive Heart Failure (CHF) 101

CHF occurs when the heart cannot adequately pump blood to the rest of the body. There are two different types: Left and Right. They both produce a wide variety of clinical symptoms. It causes imbalances among fluid and electrolytes. This post will give you the 101 on Congestive Heart Failure.

Before we jump in too deep, lets talk about the Renin-Angiotensin Aldosterone System (RAAS). Because cardiac output is decreased it stimulates the RAAS to release Angiotensin II because it is a vasoconstrictor. This will result in retaining water and sodium. That's why a lot of these patients are on fluid restrictions. A lot of times CHF will eventually lead to kidney failure. You'll watch these patients' labs for their BNP (brain natriuretic peptide), BUN, and Creatinine levels. 

Left Sided Heart Failure


We know that blood flows through the heart by coming in from the Vena Cava--> Right Atrium --> Right Ventricle--> Pulmonary Artery--> Lungs--> Pulmonary Veins--> Left Atrium--> Left Ventricle--> Aorta--> Rest of the Body.

So if we have left sided heart failure where the left side of the heart is not pumping blood as efficiently as it should and resulting in a build up of excess blood.... where does this blood back up into?

The {LUNGS}

Great! If you feel like you get these mixed up think L for Left/Lung. 

So blood backs up into the lungs. Think of what will happen if there's excess fluid putting pressure on the lungs. What does this patient look like?

Clinical Manifestations of Left Sided Heart Failure


  • Dyspnea
  • Crackles
  • Tachycardia
  • Dry, hacking cough
  • Paroxysmal nocturnal dyspnea
  • Weight gain
I think you can picture how having excess fluid on the lungs can lead to most of these symptoms. The patient develops tachycardia because the heart is trying to make up for its deficit by pumping more frequently, however the cardiac output is still not sufficient. These patients gain weight because of the excess fluid retention.

Right Sided Heart Failure


This usually occurs after left sided heart failure has occurred and is backing up so much in the lungs that it begins to back up into the right side of the heart. When it backs up in the right side of the heart, then the patient will start to have blood back up into the rest of their body. What do you think this will look like?

Clinical Manifestations of Right Sided Heart Failure


  • Generalized edema
  • Jugular venous distention
  • Abdominal distention
  • Hepatomegaly
  • Splenomegaly
  • Anorexia/Nausea
  • Nocturia
  • Weight gain
I think you can picture the blood backing up all over the body and understand how that causes the edema, jugular venous distention, abdominal distention. Nocturia occurs because oxygen demands are decreased at rest/sleep. So whereas before the RAAS was stimulated, now since demands aren't so high, there is less renal vasoconstriction and the kidneys can filter. 


Electrolyte Imbalances



  • Hyponatremia
    • Since the patient in CHF will retain water, this will dilute the sodium content in their body and cause hyponatremia.
  • Hypokalemia
    • If treated with potassium-losing diuretics excessively the patient can develop hypokalemia.
  • Hyperkalemia
    • If the patient is being treated with potassium-sparring diuretics that can lead to hyperkalemia or if they are taking an ARB and have renal impairment.
  • Hypomagnesemia
    • Typically is only a problem for patient with moderate/severe CHF and those who are being treated aggressively with thiazides or loop diuretics.
  • Metabolic Acidosis
    • As tissues get less and less oxygen, lactic acid is produced. This is a cation. So to compensate the pH and bicarb go down, now putting the patient into metabolic acidosis.
  • Respiratory Acidosis
    • When the patient has left sided heart failure, the excess fluid around the lungs prevents the patient from having an effective breathing pattern. Now the patient can't get rid of CO2 correctly and goes into Respiratory Acidosis. CO2 goes up, pH goes down.

Treatment of Congestive Heart Failure


  • Diuretics
  • Fluid Restriction
  • Sodium Restriction
  • NSAIDS are CONTRAINDICATED 

Diuretics are used to promote excretion of sodium and water through the kidneys. The patient's body may not absorb oral diuretics because of swollen intestines, so you might have to give diuretics through an IV.
Fluid is restricted to usually less than 2000 mL/day. I've had a patient as low as 1000 mL, although usually it's around 1500 mL. That's the doctor's call. I think my patient was so restricted because he was so unrestricted at home that we had to act fast. 

Sodium is restricted to usually about 2-3 grams a day. However, that seems kind of like a lot of sodium to me. The normal healthy adult is supposed to get no more than 2300 mg. Granted, I usually exceed that (thanks to keeping track of my diet via MyFitnessPal). But still, you get the point. Low salt. 

You don't want these patients to use NSAIDS because they can decrease renal blood flow even more which will lead to taking on more fluid retention. So make sure if your patient is taking a diuretic and not seeing results like they should, ask them about their use of NSAIDS.


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Ok. I talked a lot about the RAAS, and diuretics, so you might want to go back and look at my posts on them:
Renin-Angiotensin-Aldosterone System
Diuretics: Everything a Nurse Needs to Know

What are some things that you are struggling to understand in school right now? Leave a comment below and I will be happy to make a post on that topic!!

Xoxo,

Nightingale


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