Updated: 10/4/2018

Cardiac / Vascular Function Curves

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Overview
  • Cardiac output (CO) curve 
    • describes a state of cardiac function
    • a plot of the relationship between CO and right atrial pressure 
      • ↑ venous return → ↑ right atrial pressure → ↑ end-diastolic volume (EDV), end-diastolic fiber length → ↑ CO
      • ↓ venous return → ↓ right atrial pressure → ↓ EDV, end-diastolic fiber length → ↓ CO
  • Vascular return curve
    • describes a state of vascular function
    • a plot of the inverse relationship between venous return and right atrial pressure
      • ↓ right atrial pressure → ↑ ΔP (systemic arteries, right atrium) → ↑ venous return
      • ↑ right atrial pressure → ↓ ΔP (systemic arteries, right atrium) → ↓ venous return
  • Mean systemic pressure
    • also known as mean circulatory pressure
    • the x-intercept of the vascular function curve
    • shows pressure that would be measured throughout cardiovascular system if the heart were stopped
      • stopping the heart guarantees that pressure is equal throughout the vasculature
Inotropic Effects
 
  • Inotropy describes the state of cardiac contractility
  • Positive inotropy (↑ contractility)
    • positive inotropic agent → ↑ cardiac contractility, ↑ stroke volume, and ↑ CO
      • e.g., sympathetic nervous system activity, and digitalis
    • CO curve shifts upward
    • new steady state or equilibrium → ↓ right atrial pressure (EDV)
      • ↓ right atrial pressure → more blood is ejected from the heart on each beat as a consequence of increased contractility and increased stroke volume
  • Negative Inotropy (↓ contractility
    • negative inotropic agent → ↓ cardiac contractility, ↓ stroke volume, ↓ CO
      • e.g., congestive heart failure and narcotic overdose
    • CO curve shifts downward  
    • new steady state, or equilibrium → ↓ CO, ↑ right atrial pressure (EDV)
      • ↑ right atrial pressure → less blood is ejected from the heart on each beat as a consequence of decreased contractility and decreased stroke volume
  • Effects of changes in blood volume
    • increases in blood volume
      • ↑ blood volume (e.g., transfusion) → ↓ venous compliance → ↑ mean systemic pressure
        • ↓ venous compliance → blood is shifted from veins to arteries
      • venous return curve shifts to the right
      • new steady state or equilibrium → ↑ CO and ↑ right atrial pressure (EDV)
    • decreases in blood volume
      • ↓ blood volume (e.g., hemorrhage) → ↑ venous compliance → ↓ mean systemic pressure
        • ↑ venous compliance → blood is shifted from arteries to veins 
      • venous return curve shifts to left
      • new steady state or equilibrium → ↓ CO, ↓ right atrial pressure (EDV)
  • Effects of changes in total peripheral resistance (TPR) 
    • increase in TPR
      • vasoconstriction of arterioles → ↑ TPR
        • e.g., hemorrhage
      • ↑ TPR → ↑ mean arterial pressure (MAP) → ↑ afterload → ↓ CO
        • cardiac function curve shifts downward
      • ↑ TPR → ↓ venous return
        • venous return curve rotates counterclockwise
    • decrease in TPR
      • vasodilation of arterioles → ↓ TPR
        • e.g., exercise
      • ↓ TPR → ↓ MAP → ↓ afterload → ↑ CO
        • cardiac function curve shifts upward
      • ↓ TPR → ↑ venous return
        • venous return curve rotates clockwise
 

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Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Volume  
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Urine  
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2
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(M1.CV.143) A 60-year-old African American gentleman presents to the emergency department with sudden onset "vice-like" chest pain, diaphoresis, and pain radiating to his left shoulder. He has ST elevations on his EKG and elevated cardiac enzymes. Concerning his current pathophysiology, which of the following changes would you expect to see in this patient? Review Topic

QID: 100659
1

No change in cardiac output; increased systemic vascular resistance

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No change in cardiac output; decreased venous return

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Decreased cardiac output; increased systemic vascular resistance

75%

(18/24)

4

Decreased cardiac output; decreased venous return

25%

(6/24)

5

Increased cardiac output; increased systemic vascular resistance

0%

(0/24)

M1

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