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Fluid Filled Monitor
Harry Hoerr; Fluid Filled Monitoring
| Question | Answer |
|---|---|
| What are some components of a fluid filled system? | -Fluid filled intravascular catheter -Low compliance tubing -Pressure Transducer -Amplifier/Monitor -Fluid System |
| Will soft or hard tubing decrease natural frequency? | Soft tubing will decrease natural frequency` |
| What will small bubbles do in the fluid system? | Small bubbles might cause a decrease in the natural frequency. |
| What will large bubbles do in the fluid filled system? | Large bubbles will cause severe damping of the system. |
| How would we obtain a preferred frequency response range? | Short, stiff, wide-bore catheter (7 Fr or 18 gauge) connected directly to the tranducer with no air anywhere in the system |
| When the ventricle contracts which comes first, the pressure waveform or the flow of blood? | Whe the ventricle contracts the pressure waveform precedes the actual flow of blood. |
| When is there the biggest change in pulse pressure? diastolic or systolic? | Biggest difference in start times (i.e. pressure changes) occurs in systole |
| What is the equation for MAP? | MAP = (systolic + (distolic x 2)) / 3 |
| What percentage of the cardiac cylce is diastole? | 2/3 : The MAP pressure equation assumes that diastole is 2/3 of the cardiac cycle, which is true at a heart rate of 60 beats per minute. |
| How is the ACTUAL mean arterial pressure determined? | Actual Mean Arterial Pressure is determined by the area under the arterial pressure curve DIVIDED by the BEAT PERIOD. |
| Why is MAP a good assessment tool? | -MAP is the same in all parts of arterial tree.-MAP not affected by overshoot artifact & frequency response of the system.-Pulmonary & Systemic vascular resistance values are calculated using MAP.-MAP represents the inlet pressure of systemic & cerebral |
| Changes in the pressure waveform reflect changes in..... | Changes in pressure waveform reflect changes in cardiovascular function. (stroke volume, ventricular function, systemic vascular resistance) |
| What are some indirect manual techniques of measuring arterial blood pressure? | -Auscultation, Palpation, Auscultation assisted by doppler, Manometer oscillation observation, Photoelectric devices (pulse oximeter) |
| What are some things you need to think about when using auscultation to measure mean arterial pressure? | -May be up to 20 mmHg lower then direct. -Deflate cuff at 3mmHg/sec. -Proper cuff size -Problems with damping of the sound in patients w/ reduced stroke volume and severe vasoconstriction. Diastolic reading when sounds become muffled or disappear. |
| What are some indirect automated techniques for measuring arterial blood pressure? | -Oscillometery. -Infrasonde. -Ultrasonic determination of axial flow. -Arterial tonometry. -(All depend on adequate pulsatile blood flow to the extremities) (May determine mean pressure) (Good for following trends in stable patiens) |
| What does palpation determine? | Systolic |
| What does auscultation assisted by doppler determine? | Systolic (Easier to determine pressure in "Shocky" patients) |
| What does a manometer oscillation observation determine? | Determines systolic and mean(first oscillation-systolic, maximal oscillation-mean, minimal oscillation in hypotensive patients) |
| What does a phtotelectric device (pulse oxymeter) determine? | Systolic only (Patient motion a problem, problems when arterioloes of extremities constricted. |
| What are regional arterial pressure gradients due to? | -Atherosclerosis, PVD, Aortic Dissection, Arterial Embolism, Surgical Retraction, Patient Position |
| What are generalized arterial pressure gradients due to? | Severe vasoconstriction and shock. -Peripheral Vasodilation w/ rewarming during and after CPB, Normal widening of the peripheral pulse pressure |
| What are some cuff problems? | -Too Small (over estimation) -Arm Shape -Extrinsic cuff compression -limb position relative to heart. |
| What are some physiological problems and method limitations when measuring arterial pressure? | -rapid pressure changes -dysrhythmias -Severe vasoconstriction and shock -Shivering (vasoconstriction) and patient movement -beat-to-beat variations |
| Does the indirect method over or under estimate pressures? | Indirect -- Underestimates |
| Does the direct method over or under estimate pressures? | Direct -- Overestimate |
| Who are some patients that need continuous arterial pressure monitoring? | Critically ill, Injured, Undergoing major surgery, Neurologic. (Provides the ability to detect sudden changes, allows for an immediate assessment of a therapy, evaluate changes in a trend.) |
| What types of patients are in need for serial blood gasses? Indications for arterial cannulation. | Patients: Respiratory Failure, management of ventilatory support, treatment of severe acid-base disturbances (Those that need 3-4 arterial blood samples a day.) |
| What are some contraindications of arterial cannulation? | -PVD -Hemorrhagic disorders -On anticoagulants or receiving thrombotic agents |
| Where should you not insert a catheter in? | Area of Infection, Site of previous vascular surgery, Through synthetic vascular graft material. |
| How fast does the pressure wave travel? | 10 meters per second |
| How fast does blood flow travel? | 0.5 meters/second(much slower than pressure wave) |
| What does Phase 1 (inotropic component) of the Arterial wave represent? | -Energy created by contracting LV transferred to the aorta. -Pessure wave created(startsmoving down arterial tree -Aortic Valve Opens -Anacrotic rise -First part of stroke volume pumped into aortic root. |
| What does Phase 2 (volume displacement)of the arterial wave represent? | Movement of blood into the aorta fills out ans sutains the pressure pulse. Has a rounded appearance that results from continued ejection of SV/displacement of blood/distensionof arterial wall. - |
| What does the anacrotic notch represent? | Marks the change from inotropic component to displacement. |
| What does Phase 3 (late systole and diastole) represent? | -Closure of aortic valve. -Continuous decline as blood moves from aortic root to the peripheral vessels. -Undulations ma result from reflected pressure waves. |
| Does a depressed contractiliy curve have a small or large volume of area under the curve? | Large |
| Does a hyperdynamic contractility curve have a small or large volume of area under the curve? | Small |
| What could cause a high amplitude in the inotropic spike? | Inotropic Spike -- Increased rate of LV pressure generation & increased acceleration of aortic blood flow (increased BP) -Increased reflection of pressure waves from the periphery (vasoconstriction) -Overshoot artifact |
| What could cause a decrease in amplitude in the inotropic spike? | Myocardial depression -Hypovolemia -decreased reflection of pressure waves from the periphery (vasodilation) |
| What are some physiological factors affecting waveforms? | -Arrhythmias -Hypertension -Hypotension -Age -Vasoconstriction -Hypovolemia -Respiration Variation (high PEEP puts pressure on the heart) |
| What does age have to do with a waveform? | Aging -- Difference between central aortic and distal systolic pressures decrease |
| Where are some direct arterial cannulation sites? | -Radial Artery -Brachial Artery -Axillary Artery -Femoral Artery -Dorsalis Pedis Artery |
| What are some Direct Arterial Complications? | -Embolism -Vascular insufficiency (distal ischemia) -Ischemic necrosis of overlying skin -Infection -Hemorrhage -Accidental intra-arterial drug injection -Vasculitis -Arterial Dissection |
Created by:
allievisner2
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