Hemodynamics made easy

Hemodynamic Monitoring & Normal Values:

1. Blood pressure:

• a. Normal Systolic = 90-140
• b. Normal Diastolic = 60-90
• c. As BP increases CO & CI usually decrease
• b. As BP decreases CO and CI usually increase

2. Pulse Pressure:

• a. Systolic BP minus Diastolic BP
• b. Normal = 40 mmHg
• c. greater than 40 indicates decreased Stroke Volume (SV)

3. SV (Stroke Volume):

• a. Cardiac Output divided by Heart Rate
• b. Normal = 60 – 130 ml/beat
• c. It's the volume ejected per beat

4. CO (Cardiac Output):

• a. Heart Rate times SV
• b. Normal = 4.8 LPM
• c. More reliable than Mean Airway Pressure (MAP)
  

5. CI (Cardiac Index):

• a. Cardiac Output divided by Body Surface Area (BSA)
• b. Normal = 2.5 LPMm2 or simply CO/2
• c. Decreased with shock, dehydration, cardiac fail, PE.
• d. Increased with hypoxia, low BP.
• e. More reliable measurement than CO.

6. EF(Ejection Fraction):

• a. % of blood volume pushed out of heart per beat.
• b. Normal = 65 – 75%
• c. Reduced with ventricular damage

7. MAP (Mean Arterial Pressure):

• a. systolic BP + (Diastolic*2)/3
• b. Normal = 70 – 105

8. Preload: Blood that returns to ventricles at end diastolic, & refers to stretch of myocardial fibers after it is filled with blood. As the preload increases the heart function increases. As preload increases, heart function increases. Basically, it's the stretching of the heart before contraction. The more blood returned to the heart, the more the stretch will be. The means of measuring preload are:

a. PCWP (Pulmonary Capilary Wedge Pressure):

• 1. Measures left heart function
  
• 2. Normal = 5 – 12 mmHg (same as PAP diastolic)
• 3. greater than 18 = edema forming in lungs (if no signs CHF think ARDS)
• 4. greater than 25 = edema in lungs from left heart failure (CHF)
• 5. greater than 5 – 12 + edema = noncardiogenic edema (ARDS)
• 6. greater than 12 may also indicate Mitral valve stenosis

b. CVP (Central Venous Pressure):

• 1. Measures right heart function
  
• 2. Used to monitor systemic venous drainage (fluid levels)
• 3. Normal = 2 – 6 mmHg
• 4. less than 5 = hypovolemia, fluid restriction, diuretics shock, hemorrhage, vasodilators (Nipride, Morphine) blood thinners, peep, ippb
• 5. greater than 7 = hypervolemia, fluid challenge, increased SNS tone (fight or flight), shock, slow HR, decreased ejection fraction (CHF, pump failure, Aortic valve failure, thick blood)

9. Afterload: Resistance heart must work against, or blood that returns & fills the atria. All other values constant, has an inverse relationship with CO, and is indirectly monitored by Blood Pressure. This is measured by:

a. SVR (Sytemic Vascular Resistance):

• 1. Formula: (MAP minus CVP) divided by CO
  
• 2. Normal = 900 – 1400 dynes or les than 20 mmHg/L/min
• 3. Increased = HTN = vasoconstriction, increased SNS tone, cardiac stimulants (EPI, alpha action drugs), thick blood, narrow valves.
• 4. Decreased by vasodilators, decreased WOH, adequate preload, alpha blockers (Regitine, Dibenzylene), decreased SNS tone.

b. PVR (Pulmonary Vascular Resistance):

• 1. (meanPAP – PCWP)/CO
• 2. Normal = 150 – 250 dynes or less than 2.5 mmHg/L/min
• 3. Increased with hypoxia, pulmonary hypertensin, PE

c. PAP (Pulmonary Artery Pressure):

• 1. Monitors blood moving into lungs, afterload of right ventricle
• 2. Normal is 25/8 (mean = 14)
• 3. PAP diastolic can be used to estimate PCWP.

10. Cardiac Electrolytes:

• a. Potassium: Increases and decreases in this result in majority of cardiac arrhythmias.
• b. Magnesium: Low Mg associated with low K. Results in numbness, tingling, contractions, cramps, seizures, & cardiac arrhythmias.

For a printable cheat sheet with this information click here.

For more information, check out Nurse Bob's Hemodynamic Overview.

Graph above compliments of Kettering National Seminar's CRT/RRT Studyguide.