Hemodynamics Flashcards
CO
4-8 L/min
HR x SV
CI
2-4 L/min based on BSA
SV
50-100 mL
Amount of blood ejected with each beat
Affected by preload, afterload, and contractility
MAP
> 65
CVP
2-8 mmHg
The pressure of blood in the thoracic vena cava, near the right atrium
Reflects the amount of blood returning to the heart (PRELOAD) and the ability of the heart to pump the blood into the arterial system
Pulmonary Artery Pressure (PAP)
20–25 / 8–10 mmHg
PCWP
4-12 mmHg
Indirect estimate of L atrium pressure
L sided PRELOAD
SVR
900-1400 dynes/sec/cm
Pressure the Left ventricle encounters to push blood into the body
LEFT SIDED AFTERLOAD
PVR
150-300 dynes/sec/cm
Pressure the Right ventricle encounters to push blood into the pulmonary arteries
RIGHT SIDED AFTERLOAD
Subclavian venous saturation (ScVO2)
70%
Measured by central line
Mixed venous saturation (SvO2)
60-80%
Measured by Pa catheter
Beta 1 receptors
Located: heart
Agonism: Increases chronotropy (HR) and inotropy (contractility)
Beta 2 receptors
Located: Bronchioles and blood vessels
Agonism: Bronchodilates, vasodilates
Alpha 1 Receptors
Located: Blood vessels
Agonism: vasoconstrict
D1, D2 Receptors
Located: Heart
Agonism: Increase chronotropy and inotropy
D4, D5 Receptors
Located: blood vessels
Agonism: vasoconstrict
Vasopressin 1 Receptors
Located: blood vessels
Agonism: vasoconstrict
Preload
Blood returning to the heart and available for ejection (Ventricle filling)
Inadequate: Tachycardia, dysrhythmias, valvular stenosis, tamponade, hypovolemia, diastolic dysfunction
Tx–volume expanders
Excessive/increased: Bradycardia, tricuspid/mitral valve regurgitation, hypervolemia
Tx–Correct volume overload (diuretics, vasodilators, milrinone, nitroglycerine, hydralazine)
Contractility
Squeeze of the heart
LV/RV ejection
Inadequate–CAD, ischemia/infarct causing RWA, negative inotropes (BB, CCB)
Afterload
Pressure in the vasulature the heart must overcome to pump blood out
Measured by SVR and PVR
Increased afterload: systemic/pulm HTN, valvular stenosis
Decreased afterload: vasodilators
TX FOR INCREASED SVR: nitroprusside, carvedilol, labetalol (alpha-beta blockers), CCB, hydralazine, ACEI-ARBs
TX FOR INCREASED PVR: NO, inhaled prostaglandins, PDE-inhibitors, endothelin receptor antag
VO2 (volume O2)
200-300 mL/min
Amount of oxygen extracted by peripheral tissues over one minute
Commonly indexed by patient’s BSA
Normal index 110-160 ml/min/m2
Phenylephrine
MOA: Alpha 1 agonist –> peripheral vasoconstriction
Indications: Distributive shock, hypotension w/ tachycardia
ADE: Splanchnic hypoperfusion, peripheral vasoconstriction
Norepinephrine
MOA: Mixed alpha-1 and beta-1 agonist –> peripheral vasoconstriction (a1), increased chronotropy and inotropy (B1)
Indications: Distributive shock
ADE: Arrhythmias, peripheral vasoconstriction
Epinephrine
ADE: Mixed alpha-1 and beta-1 agonist –> peripheral vasoconstriction (a1), increased chronotropy and inotropy (B1)
Indications: Distributive shock
Cardiac arrest, anaphylaxis, heart blocks, bradycardia
ADE: Splanchnic hypoperfusion, increased myocardial O2 demand
Dopamine
MOA: Mixed, dose dependent–
– dopaminergic agonist –> increased chronotropy and inotropy
– beta-1 agonist –> increased chronotropy and inotropy
– and alpha-1 agonist –> peripheral vasoconstriction
Indications: distributive shock, bradycardia
ADE: Tachycardia, cardiac dysrthymias
Vasopressin
MOA: V1 receptor agonist –> peripheral vasoconstriction
Indications: Refractory septic shock, Diabetes insipidus, GI bleeding
ADE: Splanchnic hypoperfusion
Dobutamine
MOA: Beta-1 agonist –> increased chronotropy and inotropy
Indication: Cardiogenic shock, decompensated heart failure
ADE: hypotension, increased myocardial oxygen demand
Milrinone
ADE: Phosphodiesterase 3-inhibitor
Indication: Cardiogenic shock, decompensated heart failure
ADE: Hypotension
Thrombocytopenia
Arrhythmias
Isoproterenol
MOA: Beta-1 and Beta-2 agonist –> increased chronotropy/inotropy, bronchodilator, peripheral vasodilator
Indication: Bradyarrhythmias, AV block
ADE: hypotension, arrhythmias
