II. Physiology

  1. Blood Volume
    1. Adult: 7% or 70 ml/kg (~5 Liter Blood Volume for a 70 kg man)
    2. Child: 8-9% (80-90 ml/kg for a child)
  2. Blood Loss
    1. Each 10% drop in Blood Volume represents ~500 ml blood loss in average adult male (70 kg)

III. Findings: Class I Hemorrhage - Minimal Blood Loss

  1. Characteristics
    1. Blood Volume Loss <15%
    2. Adult blood loss <750 ml
  2. Cardiovascular
    1. Heart Rate normal or mild increase
    2. Pulses normal
    3. Blood Pressure normal
    4. pH normal
  3. Respiratory: Rate normal
  4. Neurologic: Slightly anxious
  5. Skin
    1. Warm and pink
    2. Capillary Refill brisk (<2 seconds)
  6. Renal: Normal Urine Output
    1. Adults: >0.5 ml/kg/hour (>30 cc/hour)
    2. Children: >1 ml/kg/hour
    3. Infants <1yo: >2 ml/kg/hour
  7. Reponse to Crystalloid Bolus (2000 ml in adults, 20 ml/kg in children)
    1. Rapid response with normalization of Vital Signs

IV. Findings: Class II Hemorrhage - Mild Blood Loss

  1. Characteristics
    1. Blood Volume Loss: 15-30%
    2. Adult: 750-1500 ml of blood loss
  2. Cardiovascular
    1. Tachycardia
    2. Diminished peripheral pulses
    3. Blood Pressure normal
    4. Normal pH
  3. Respiratory
    1. Mild Tachypnea
  4. Neurologic
    1. Irritable
    2. Confused
    3. Combative
  5. Skin
    1. Cool extremities
    2. Mottling
    3. Delayed Capillary Refill
  6. Renal
    1. Oliguria
    2. Increased specific gravity
  7. Response to Crystalloid Bolus (2000 ml in adults, 20 ml/kg in children)
    1. Moderate response, but Tachycardia may recurr

V. Findings: Class III Hemorrhage - Moderate Blood Loss

  1. Characteristics
    1. Blood Volume Loss: 30-40%
    2. Adults: 2000 ml blood loss
  2. Cardiovascular
    1. Significant Tachycardia
    2. Thready peripheral pulses
    3. Hypotension
    4. Metabolic Acidosis
  3. Respiratory: Moderate Tachypnea
  4. Neurologic
    1. Irritable
    2. Lethargic
    3. Diminished pain response
  5. Skin
    1. Cool extremities, mottling or pallor
    2. Prolonged Capillary Refills
  6. Renal
    1. Oliguria
    2. Blood Urea Nitrogen (BUN) increased
  7. Reponse to Crystalloid Bolus (2000 ml in adults, 20 ml/kg in children)
    1. Transient response with recurrent Hypotension and Tachycardia
    2. Blood Transfusion needed (typically type specific blood)
    3. Surgical intervention is likely

VI. Findings: Class IV Hemorrhage - Severe Blood Loss

  1. Characteristics
    1. Blood Volume Loss: >40%
  2. Cardiovascular
    1. Severe Tachycardia
    2. Thready central pulses
    3. Significant Hypotension
    4. Significant acidosis
  3. Respiratory: Severe Tachypnea
  4. Neurologic
    1. Lethargic
    2. Coma
  5. Skin
    1. Cold extremities
    2. Pallor
    3. Cyanosis
  6. Renal
    1. Anuria
  7. Reponse to Crystalloid Bolus (2000 ml in adults, 20 ml/kg in children)
    1. No significant response with recurrent Hypotension and Tachycardia
    2. Massive Blood Transfusion needed (starting with O negative blood)
    3. Emergent surgical intervention

VII. References

  1. (2012) ATLS 9th ed, ACOS, Chicago, p. 69, 74

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