FMP Cardiac Critical Care – Questions & Answers
Cardiac responses to hypoxia - ✔️ Hypoxia can result from changes
in perfusion status
-Pump, pipe, fluid, or flow issues
-Ex. pulmonary vasoconstrictive response = hypercapnia, hypoxia, and
resulting acidosis can increase pulmonary hypertension, creating a spiral that
worsens perfusion and in turn increases hypoxia
Changes in contractility
-Inotropic changes
-Frank Starling law (greater stretch from preload = greater contractile force =
greater stroke volume)
Changes in rate
-Chronotropic changes
-Heart rate [HR] increases in an attempt to increase stroke volume [SV]
maintain adequate cardiac output [CO]
- CO = SV x HR
Cardiac Output (CO) - ✔️ CO = SV x HR
Normal Cardiac Index (2.5-5 L/min)
-Assessment of the cardiac output based on the patient's size (BSA)
Dependent on
-Preload
-Afterload
-Stroke volume
-Contractility
Force of left ventricle contraction must overcome pressure in the aorta in
order to create forward flow
Pulmonary Vascular Resistance (PVR) - ✔️ Measures afterload of the
right ventricle
-Normal = 50-250 dynes
,Increased PVR
-Acidosis
-Hypercapnia
-Hypoxia
-Atelectasis
-ARDS
Decreased PVR
-Alkalosis
-Hypocapnia
-Vasodilating drugs
Systemic Vascular Resistance (SVR) - ✔️ Measures afterload of the
left ventricle
-Normal = 800-1200 dynes
Increased SVR
-Hypothermia
-Hypovolemic shock
-Decreased CO
Decreased SVR
-Anaphylaxis
-Neurogenic shock
-Septic shock
-Vasodilating drugs
Heart Sounds - ✔️ S1: "Lub"
-Mitral and tricuspid valves close
S2: "Dub"
-Aortic and pulmonic valves close
S3: "dub-lub-dub" (second sound pronounced)
-Overfilling of left ventricle
-Congestive heart failure, chordae tendineae dysfunction
S4: "lub-dub-dub" (first sound pronounced)
-Weak left ventricle
, -Hypertrophic cardiomyopathy, hypertension (HTN), new or old infarction
Heart Valve Auscultation Points - ✔️ "All Physicians Take Money"
Aortic valve
-2nd to 3rd intercostal, right of sternum
Pulmonic valve
-2nd to 3rd intercostal, left of sternum, opposite of aortic valve
Tricuspid valve
-4th to 5th intercostal space, left of sternum
Mitral valve
-4th to 5th intercostal space, left midclavicular line
Essential Electrolyte Functions - ✔️ Sodium
-Flows into the cell to initiate depolarization
Potassium
-Flows out of the cell to initiate repolarization
-Hypokalemia: increased cardiac irritability
-Hyperkalemia: decreased automaticity/conduction
Calcium
-Maintains depolarization of pacemaker cells/myocardial contractility
-Hypocalcemia: decreased contractility and increased irritability
-Hypercalcemia: increased contractility
Magnesium
-Stabilizes cell membrane
-Hypomagnesemia
Cardiac Monitoring - ✔️ Change in structure or function of cardiac
cells can be seen on EKG
Cardiac monitoring
-Continuous monitoring of patients condition, often by 3, 5, or 12 lead
Cardiac responses to hypoxia - ✔️ Hypoxia can result from changes
in perfusion status
-Pump, pipe, fluid, or flow issues
-Ex. pulmonary vasoconstrictive response = hypercapnia, hypoxia, and
resulting acidosis can increase pulmonary hypertension, creating a spiral that
worsens perfusion and in turn increases hypoxia
Changes in contractility
-Inotropic changes
-Frank Starling law (greater stretch from preload = greater contractile force =
greater stroke volume)
Changes in rate
-Chronotropic changes
-Heart rate [HR] increases in an attempt to increase stroke volume [SV]
maintain adequate cardiac output [CO]
- CO = SV x HR
Cardiac Output (CO) - ✔️ CO = SV x HR
Normal Cardiac Index (2.5-5 L/min)
-Assessment of the cardiac output based on the patient's size (BSA)
Dependent on
-Preload
-Afterload
-Stroke volume
-Contractility
Force of left ventricle contraction must overcome pressure in the aorta in
order to create forward flow
Pulmonary Vascular Resistance (PVR) - ✔️ Measures afterload of the
right ventricle
-Normal = 50-250 dynes
,Increased PVR
-Acidosis
-Hypercapnia
-Hypoxia
-Atelectasis
-ARDS
Decreased PVR
-Alkalosis
-Hypocapnia
-Vasodilating drugs
Systemic Vascular Resistance (SVR) - ✔️ Measures afterload of the
left ventricle
-Normal = 800-1200 dynes
Increased SVR
-Hypothermia
-Hypovolemic shock
-Decreased CO
Decreased SVR
-Anaphylaxis
-Neurogenic shock
-Septic shock
-Vasodilating drugs
Heart Sounds - ✔️ S1: "Lub"
-Mitral and tricuspid valves close
S2: "Dub"
-Aortic and pulmonic valves close
S3: "dub-lub-dub" (second sound pronounced)
-Overfilling of left ventricle
-Congestive heart failure, chordae tendineae dysfunction
S4: "lub-dub-dub" (first sound pronounced)
-Weak left ventricle
, -Hypertrophic cardiomyopathy, hypertension (HTN), new or old infarction
Heart Valve Auscultation Points - ✔️ "All Physicians Take Money"
Aortic valve
-2nd to 3rd intercostal, right of sternum
Pulmonic valve
-2nd to 3rd intercostal, left of sternum, opposite of aortic valve
Tricuspid valve
-4th to 5th intercostal space, left of sternum
Mitral valve
-4th to 5th intercostal space, left midclavicular line
Essential Electrolyte Functions - ✔️ Sodium
-Flows into the cell to initiate depolarization
Potassium
-Flows out of the cell to initiate repolarization
-Hypokalemia: increased cardiac irritability
-Hyperkalemia: decreased automaticity/conduction
Calcium
-Maintains depolarization of pacemaker cells/myocardial contractility
-Hypocalcemia: decreased contractility and increased irritability
-Hypercalcemia: increased contractility
Magnesium
-Stabilizes cell membrane
-Hypomagnesemia
Cardiac Monitoring - ✔️ Change in structure or function of cardiac
cells can be seen on EKG
Cardiac monitoring
-Continuous monitoring of patients condition, often by 3, 5, or 12 lead
