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hemodynamics
AD245 nursing
Question | Answer |
---|---|
Preload | volume of blood in ventricle at end of diastole (REST) - the amount of blood in the ventricle before the next beat. |
Afterload | Resistance to the flow of blood from ventricles thru the aortic and pulmonic valves. |
Contractility | Strenght of contraction. |
Starlings law | As preload increased, CO increases until it reaches a PEAK and then it fails (CO will drop, blood continues to fill till it over flows and it will fail) |
Increased Preload | Increased CO |
What increases preload? | Fluids and vasopressors |
What decreases preload? | hemorrhage and fluid loss |
Increased afterload = | decreased CO |
What causes increased afterload? | HTN |
What decreases afterload? | vasodilators. |
Decreased contractility = | Decreased CO |
What increases contractility? | Adernergic vasopressor |
What decreased contractility? | MI and CHF |
Which labs are considered before giving a swan? | K, Na, mg and Ical |
K (potassium) | 3.5 to 5 |
Na | 135 -145 |
mg | 1.6 to 2.6 |
ical | 4.5 to 5.6 |
CVP | Central venous pressure |
CVP Norm | 4 to 10 |
Where is CVP measured? | Right atrium |
What does CVP measure? | Right atrium pressure |
What does increase CVP indicate? | High blood volume & increase venous tone = decrease R ventricular contractitliy |
What instrument do you need for CVP? | Artline....no need for swan, but swan can measure it if in place. |
CO | 4L to 8L/min of bloodflow |
How many beats per min is a normal HR? | 60 to 80 |
How much blood flow per min is normal for stroke volume? | 60 to 70ml |
Calculation that determines CO | HR x SV = Number of heart beats/min x the amount of ml of blood per min |
What measures the CO? | The swan |
Where is CO measured? | Right atrium |
Example of HR x SV = ??? 80 bpm x 70ml/min = | CO 5600 ml/min or 5.6 L/min |
Cardiac index normal? | 2.8 to 4.2 L/min |
What measures CI | swan ganz |
Where is it measured? | R atrium |
Why is CI better than CO? | Heart is based on clients weight and height. |
SCV02 | Central venous oxygen saturation |
what does swan measure SCVO2? | oxygen saturation rate, the oygen reserve (oxygen not used by the body) |
normal value for SCVO2? | ~ 70% |
what devices measures SCVO2? | artline, not swan |
SvO2 is measured with what? | Swan |
Normal SvO2? | 60 to 80% |
What does <60% of SvO2 indicate? | Decreased oxygen is being delivered to the body. |
What causes <60% of Sv02 | Body is consuming more oxygen because of decreased CO, decreased Hgb, decreased vent support, |
What does >80% Sv02 indicate? | Body is not taking in the blood d/t shunting. Body is not getting enough oxygen |
PA or (PAP)normal | 25/10 mmHg |
what instrument measures the PAP? | Need swan |
What does PAP measure? | Left preload and R Afterload |
What causes an increase in PAP? | Respiratory disorders (pneumonia, ARDS, emphysema) fluid, atelectasis, chest, trauma and pulmonary htn |
PCWP | 6 to 10 mmHG |
This is measured when balloon is inflated and is needs swan ganz? | PCWP |
When balloon is inflated, what does PCWP measure? | Right afterload and Left preload |
When PCWP is >10 mmHg, this indicates? | Left sided heart failure r/t pressure or high fluid. |
MAP normal | 70 to 90 mmHg |
In some cases, what value is okay for MAP? | < 65 mmHg |
What value of MAP indicuated underperfusion? | <60 mmHg |
MAP is measured? | Art line |
SVR measures ? | Systemic vascular resistance, via an artline or B/P |
SVR norm | 900 to 1600 |
What does SVR measure | Left side afterload. |