Hemodynamics #4 Flashcards
Swans: Red Short Pigtail
Controls the balloon and the balloon tip.
-can be used to wedge the catheter and float the cat into place
Small blue pigtail
Allows volumes to be infused greater than 2 to 5 mL per hour
- to flush the lines clear end of line
- square wave test (test the dynamic properties of the line and determine damping)
Tubing Resonance Frequency
Tubing has high-frequency resonance so low frequency heart rate doesn’t get amplified by the system
Transducer level
Needs to be placed level with the phlebostatic axis level with the right atrium - fourth intercostal space mid-auxiliary line
-patient needs to remain on his or her back
Zeroing the monitor
Turn stopcock off to the patient
- open up Post to allow atmospheric pressure to enter transducer
- select waveform and zero
- atmospheric pressure no longer contributes to pressure readings on Monitor
Square wave test proper dynamic properties
Damping is correct
-determined between two and five bounces after square wave test
Square wave test hypodynamic
No bounce noted goes directly back into waveform
- hypodynamic. Muffled reading
- overdamp
- rounded or slurred waveforms
Hypodynamic waveform causes
Overdamping caused by air in the line, kinked line,
- increased pressure in pressure bag, failure to Rezero at altitude.
- line more stiff (frozen)
- stop cock closed to patient
Square waveform hyperdynamic
More than five bounces after square waveform
-Underdamping
Hyperdynamic causes
- too much tubing, distal placement
- pressure bag pressures less than 300
- failing to Re-zero on descent (bag looses pressure)
- less stiff
State Anatomic relation w/ arteries, veins nerves and lymphatics
Peripherally moving medial: Nerve, artery, vein, empty space, lymphatics
Define Whipping
Exaggerated waveform readings with distal peripheral artery lines.
-caused by inherent dynamic properties of patients extended vascular system between heart and insertion site
Allen test negative and positive
Negative: (normal) color returns in 6 seconds
-adequate ulnar blood supply to hand.
Positive (abnormal) color takes longer than 6 sec to return to hand. Inadequate ulnar blood supply.
Arterial waveform sharp upslope and dichroic notch.
Sharp upslope: systole (peak represents systolic pressure)
Dicrotic notch: closure of the last heart valve up stream (aortic valve)
(Pulmonic valve is in PA)
-beginning of diastole
Slurring of dictotic notch
Aortic stenosis
Notch becomes blended in.
-Elastic properties of valve bounce back against pressure which causes upper deflection In dicrotic notch.
-stenotic valve does not have these elastic properties. No bounce.
Acrotic notch
On ascending side.
- also represents aortic stenosis.
- systole occurs initial pressures are not enough to force stenotic valve open and slurs upslope.
JGA process of determining high renal flows
Higher flows do not allow adequate time for Na absorption in kidneys. Juxtaglomerular Apparatus sense excess salt, determined higher than normal volume and stimulates elimination of water.
JGA process of determining low renal flows
Less filtrate, flow through nephron is reduced. More Na absorbed due to prolonged absorption time. JGA senses lack of salt. Works to increase BP and water reabsorbtion via Renin release.
Renin-Angiotensin system
- Renin reacts with angiotensinogen in blood
- angiotensinogen converts to angiotensin I in blood
- Angiotensin I interacts sigh angiotensin converting enzyme (ACE) (found in pulmonary epithelium) and converts to angiotensin II
- Angiotensin II is most potent vasoconstrictor
- circulating angiotensin II stimulates kidneys to release aldosterone
- Aldosterone causes Na/K pumps into high gear. Retains Na and water.
Renin-Angiotensin system and cardiogenic shock.
Worsens condition due to sick pump having to overcome increased fluids and vasoconstriction.
- Stretching of atrium promotes release of Atrial Natriuretic Peptide (ANP) aka BNP which interferes w/ aldosterone release.
- can be used to determine degree of heart stretching (CHF primary cause)
- natricore is synthetic ANP (vasodilation & inhibits aldosterone release)
Pressure line readings and spontaneous vs ventilated considerations
Should always be assessed at end exhalation
-baseline wonder will reverse axes when change from spontaneous to mechanical ventilation.
