Chapter 8 Hemodynamic Monitoring Flashcards
- Hemodynamic monitoring common in critical care unit
* Studies relationships among several variables:
- Heart rate
- Blood flow
- Oxygen delivery
- Tissue perfusion
Cardiovascular system • Pressure = • Pressure— • Flow: • Resistance:
- Pressure = flow × resistance
- Pressure—force exerted on the liquid
- mm Hg
- Flow: amount of fluid moved over time
- L/min or mL/min
- Resistance: opposition to flow
CARDIAC OUTPUT • Cardiac output: • CO = • Ejection fraction— • Normal:
• Cardiac output—volume of blood ejected from heart/min
• CO = HR × Stroke volume (volume of blood ejected with each beat)
• 4 to 8 L/min
• Ejection fraction—fraction of blood ejected with
each beat
• Normal 60% to 70%
PRELOAD • Degree of? • Volume of blood in? • Frank-Starling law • Example =
- Degree of muscle fibers’ stretch before systole
- Volume of blood in ventricle prior to contraction (LVEDV/LVEDP)
- Frank-Starling law
- Increased stretch = increased volume
- Stretch is within physiological limits
- Example = balloon
AFTERLOAD • Pressure or? • Related to? • Systemic vascular resistance? • Pulmonary vascular resistance? • Example =
• Pressure or resistance against flow
• Related to lumen size and viscosity
• Systemic vascular resistance: Force overcome by the left ventricle upon contraction
• Pulmonary vascular resistance: Force overcome by the right ventricle upon contraction
• Example = opening door against wind
CONTRACTILITY

- Force of ventricular contraction
* How well the heart is pumping
SYSTEMIC VASCULAR RESISTANCE (SVR)
- Peripheral vascular resistance
- Diameter of blood vessels
- Arterial BP = CO × SVR
CARDIAC OUTPUT VERSUS INDEX
• Index is a better assessment; based on?
• CI =
• Calculated on?
- Index is a better assessment; based on body size
- CI = CO ÷ body surface area
- Calculated on the computer after entering patient’s height and weight
HEMODYNAMIC MONITORING
• Noninvasive modalities
• Noninvasive blood pressure
• Assessment of jugular venous pressure
• Assessment of serum lactate levels (to see if the patient is meeting their metabolic needs).
-normal they will go to med surg or tele
-elevated they need more intensive care
-correlation/indicator if patient will decompensate and crash
central venous pressure normal range
Normal is 7 to 9 cm
HEMODYNAMIC MONITORING
• Invasive modalities
- Arterial pressure monitoring
- Pulmonary artery pressure monitoring
- Right atrial pressure monitoring
COMPONENTS OF INVASIVE HEMODYNAMIC MONITORING (5)
- Invasive catheter
- Noncompliant pressure tubing
- Transducer and stopcocks
- Flush system
- Bedside monitor
ACCURACY IN HEMODYNAMIC MONITORING
• Level =
• Zero reference
• Dynamic response testing
• Level = phlebostatic axis
• Fourth intercostal space, midaxillary line
• Approximate level of right atrium
• Zero reference
• Negate atmospheric pressure
• Zeroing stopcock is leveled at phlebostatic axis and “zeroed”
• Dynamic response testing
• Square wave test (to make sure tube is in proper place and you are getting right reading from it)
-always assess patient and make sure your readings are accurate
ARTERIAL PRESSURE MONITORING
Invasive technique to monitor arterial blood pressure
• Sites:
1) Radial artery
• Allen’s test prior to insertion to verify collateral circulation in the extremity
• Issues related to predictability of Allen’s test
2) Brachial artery
3) Femoral artery
ARTERIAL PRESSURE MONITORING
• Equipment
- Pressurized flush solution with transducer
- Pressure at 300 mm Hg (Why does this need to be high?) because it has to counteract their blood pressure.
- A-line catheter (angiocath)
Arterial Pressure Monitoring Complications
Major complications 1) Thrombosis • Clot if flush not used appropriately 2) Embolism • Air entering system/clot dislodgment 3) Hemorrhage • Loose connections/catheter dislodgment (they can loose blood rapidly) 4) Infection (can have phlebitis of artery itself)
RAP/CVP MONITORING

1) Right atrial pressure (RAP)—catheter in right atrium
• Proximal port of pulmonary artery catheter
2) Central venous pressure (CVP)—catheter in superior or inferior vena cava
• Triple lumen
- Values similar and terms interchanged
RAP/CVP
• Direct measurement of?
• Right ventricular (RV) preload or?
• Normal value
- Direct measurement of pressure in right atrium
- Right ventricular (RV) preload or right ventricular end diastolic pressure (RVEDP)
- Normal value: 2 to 6 mm Hg
- Recorded end exhalation as a mean value