THAT TERMINOLOGY
What is hemodynamics?
Hemodynamics:
•Flow of blood & factors affecting it
•Study of blood circulation
•Hemodynamic monitoring involves assessment and interpretation of several physiological parameters pertaining to the cardiovascular and pulmonary systems
Name 3 examples of non-invasive hemodynamic monitoring.
Examples of non-invasive hemodynamic monitoring:
•HR,
•NIBP,
•SpO2,
•Respiratory variables,
•Urine output,
•ECG monitoring
•JVP
•Cap refill
How could normal sinus rhythm affect CO?
NSR = Normal cardiac output
Name 2 arterial line insertion sites
•Brachial
•Radial
•Femoral
What is cardiac output?
Cardiac output:
•Amount of blood pumped out of the LV in 1 minute (L/min)
•CO = HR x SV
Name 5 factors that may lower cardiac output
•Affecting rate (i.e. drugs, brady-arrhythmias)
•Affecting contractility (i.e. heart attack)
•Affecting preload (i.e. hypovolemia, systemic vasodilation)
•Affecting afterload (i.e. systemic vasodilation)
How could underlying A-fib with V-paced beats affect CO?
Underlying Afib with V-paced beats
• Good rate – normal cardiac output, but loss of atrial kick (~30% of cardiac output)
Name 2 indications for an arterial line
Patients with:
•Fluctuating, unstable blood pressure
•Cardiovascular instability
•Vasoactive IV infusions
•Requirement for frequent arterial blood gas sampling
What is preload?
Preload:
•End-diastolic stretch on myocardial muscle fibers, the degree to which cardiac muscle fibers are stretched prior to contraction
•Muscle fiber length at end-diastole
Administration of __________contributes to increased preload?
IV fluid
- Preload is the volume of blood in the ventricles at the end of diastole. Administering fluids increases this volume
How could a run of SVT affect CO?
Run of SVT - decrease in cardiac output due to a decreased filling time.
Do you need to use an alcohol swab before drawing blood from an arterial line?
Yes, you are accessing the patient’s circulation system – aseptic technique!
What is afterload?
Afterload:
•Total force opposing ventricular ejection
•The force the ventricles must develop to pump blood effectively against the pressure present in the vascular system
•Resistance or pressure the muscles of the muscle of the ventricles must overcome to open the pulmonary or aortic valves and eject blood
What medication, would you give in the ED, will enhance the heart's contractility, directly increasing cardiac output?
Digoxin
May also be ordered these meds for CCU patients:
Dobutamine
Milrinone
Isoproterenol
Bradycardia-induced low cardiac output may require __________?
- Atropine or epinephrine to increase HR
- Transcutaneous pacing
- Vasoactive medications to support perfusion
What is your priority action if an arterial line becomes dislodged?
Apply pressure and call the MD
Explanation: Immediate pressure is needed to prevent exsanguination; notify the provider urgently
What is contractility?
Contractility:
•Strength of the heart's contraction independent of preload and afterload.
•Affected by sympathetic stimulation, medications, and electrolyte levels.
Low cardiac output often triggers _______ & ________.
Low cardiac output often triggers compensatory tachycardia and hypertension.
How could 3rd degree heart block affect CO?
• Loss of atrial kick (~30% of cardiac output)
• Ventricular rate is low – risk of low cardiac output – pt potentially symptomatic at a rate of 40
What is the priority if the arterial waveform becomes dampened?
Check for kinks or air bubbles
Explanation: A dampened waveform may indicate mechanical issues like kinks, bubbles, or clotting.