Hemodynamic Monitoring and Interpretation
6
Core Parameters
CVP PAP PAOP CO CI SVR
2-6 mmHg
Normal CVP
Right ventricular preload
4-12 mmHg
Normal PAOP
Left ventricular preload
Key Parameters
memorize these normal ranges, they show up everywhereCVP
2-6 mmHg
RV preload
PAP
20-30/8-15
Pulmonary pressure
PAOP
4-12 mmHg
LV preload
CO
4-8 L/min
Pump output
CI
2.5-4.0
Output per m²
SVR
800-1200
Afterload
SvO2
60-80%
O₂ consumption
Shock State Pattern Recognition
PAOP reflects LEFT heart. CVP reflects RIGHT heart. Mixing these up is the #1 error.
| Shock Type | CVP/PAOP | CO/CI | SVR |
|---|---|---|---|
| Hypovolemic | ↓ Low | ↓ Low | ↑ High |
| Cardiogenic | ↑ High | ↓ Low | ↑ High |
| Distributive (early) | ↓ Low | ↑ High | ↓ Low |
| Distributive (late) | ↓ Low | ↓ Low | ↓ Low |
| Obstructive | ↑ High | ↓ Low | ↑ High |
Key Values to Memorize
CVP 2-6 mmHg
PAOP 4-12 mmHg
CO 4-8 L/min
CI 2.5-4.0 L/min/m²
SVR 800-1200 dynes
SvO2 60-80%
you know the parameters, now prove it under pressure
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Practice CCRN QuestionsExam Traps
PAOP reflects the LEFT heart, CVP reflects the RIGHT
This is the single most tested hemodynamic concept. The exam will present a scenario where values suggest left-sided failure and ask which parameter confirms it. If you pick CVP instead of PAOP, you lose the point.
Low SVR with high CO equals early septic shock
Warm, flushed, bounding pulses with a high cardiac output and low SVR screams early distributive shock. The exam loves pairing these values and asking you to identify the shock type.
PA catheter balloon must be deflated immediately after wedge reading
Leaving the balloon inflated risks pulmonary artery rupture or infarction. The exam may describe a nurse who "forgets" and ask you to identify the complication.
CVP alone is unreliable for fluid responsiveness
A single CVP reading does not predict whether a patient will respond to fluids. Trending the value or using dynamic assessments (passive leg raise, pulse pressure variation) is more reliable.
The Golden Rule
CVP = right side. PAOP/Wedge = left side. NEVER mix them up. This is the #1 hemodynamic exam error.
Septic Shock Pattern
Low SVR with high CO? Think early septic shock (warm shock). Low SVR with low CO? Late septic (cold shock).
Your heart is a two-sided pump. The right side pushes blood to the lungs. The left side pushes blood to the body. CO and CI tell you how much water the pump moves per minute.
CVP measures pressure entering the RIGHT pump. PAOP measures pressure leaving the lungs and entering the LEFT pump. They are on different sides of the plumbing system.
SVR measures how tight or relaxed the pipes are. Tight pipes (high SVR) = the pump works harder. Relaxed pipes (low SVR) = blood flows too freely and pressure drops.
When your pump is failing, pressure backs up BEHIND the failing side. Left failure = high PAOP. Right failure = high CVP. The gauges tell you which side is struggling.
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