Case Study: The Bleeding Patient - Week 3

Case Presentation

Patient Demographics

Name: James Morrison
Age: 35 years old
Gender: Male
Medical History: No significant history, non-smoker, social alcohol use
Current Medications: None

Chief Complaint

Brought in by ambulance following high-speed motorcycle accident. Reported by paramedics as having significant blood loss at scene.

History of Present Illness

James was riding his motorcycle when he collided with a vehicle. He was thrown approximately 10 meters. Bystanders reported he was initially conscious but became increasingly confused. Paramedics found him with an obvious deformity of his right femur and a deep laceration on his right thigh. Estimated blood loss at scene: 1500-2000ml. No loss of consciousness reported. He was helmeted.

Vital Signs & Physical Examination

Initial Vital Signs (Emergency Department)

Blood Pressure

82/54

mmHg

Heart Rate

128

bpm

Respiratory Rate

24

/min

Temperature

35.8

°C

SpO2

94%

room air

GCS

14

E4V4M6

Physical Examination Findings

General: Alert but confused, pale, diaphoretic, cool extremities
Airway: Patent, C-spine immobilized
Breathing: Equal air entry bilaterally, no cyanosis
Circulation: Tachycardic, thready peripheral pulses, capillary refill 4 seconds
Right Thigh: Gross deformity mid-shaft femur, 20cm open wound with active bleeding, exposed bone fragments visible
Abdomen: Soft, non-distended, no obvious injury
Neuro: Moving all extremities, confused but follows commands

Laboratory Results

Test	Result	Reference Range	Status
Hemoglobin	112 g/L	130-170 g/L	LOW
Hematocrit	34%	40-50%	LOW
WBC	15.8 x10⁹/L	4.5-11.0 x10⁹/L	HIGH
Platelets	245 x10⁹/L	150-400 x10⁹/L	Normal
Lactate	4.2 mmol/L	0.5-2.2 mmol/L	HIGH
pH	7.32	7.35-7.45	LOW
Base Excess	-4.5 mmol/L	-2 to +2	LOW
INR	1.1	0.9-1.2	Normal
Fibrinogen	1.2 g/L	2.0-4.0 g/L	LOW

Clinical Reasoning Questions

1. What classification of hemorrhagic shock is James experiencing based on his vital signs?

Class I (< 15% blood loss) Class II (15-30% blood loss) Class III (30-40% blood loss) Class IV (> 40% blood loss)

Correct! Class III (30-40% blood loss)

James shows the classic signs of Class III hemorrhagic shock:
• Systolic BP < 90 mmHg (82/54)
• Heart rate > 120 bpm (128)
• Confusion/altered mental status
• Cool, clammy skin
• Capillary refill > 3 seconds
• Estimated 1500-2000ml blood loss (James likely has ~5000ml total blood volume; 30-40% = 1500-2000ml)

Class IV would show more profound hypotension and unconsciousness.

2. What is the primary physiological mechanism causing James' tachycardia?

Direct cardiac stimulation from blood loss Baroreceptor-mediated sympathetic activation to maintain cardiac output Hypoxia stimulating cardiac centers directly Pain-induced catecholamine release only

Correct! Baroreceptor-mediated sympathetic activation

The baroreceptor reflex is a negative feedback mechanism:
• Decreased blood volume → decreased venous return → decreased stroke volume
• Decreased arterial pressure → reduced stretch of baroreceptors (aortic arch, carotid sinuses)
• Baroreceptors send fewer signals to the medulla oblongata
• Result: Decreased parasympathetic tone + increased sympathetic tone
• Effect: Tachycardia + vasoconstriction to maintain cardiac output (CO = HR × SV)

This compensatory mechanism attempts to maintain perfusion to vital organs.

3. Why is James' hematocrit (34%) NOT lower despite significant blood loss?

He is not actually bleeding as much as estimated His bone marrow is rapidly producing new red blood cells Hematocrit always stays normal in acute blood loss Fluid shifts from interstitial space dilute blood gradually, not immediately

Correct! Fluid shifts dilute blood gradually

This is a CRITICAL concept in acute hemorrhage:
• Initially: Both plasma and red cells are lost together → hematocrit stays the same
• Over 24-72 hours: Interstitial fluid shifts into intravascular space (hemodilution)
• Result: Hematocrit falls as plasma volume is restored but RBCs are not replaced
• Clinical implication: Early hematocrit can be misleadingly normal in acute blood loss

Hemoglobin (112 g/L) is also diluted; James' true pre-hemorrhage hemoglobin was likely ~150 g/L.

4. What component of James' blood should be prioritized for transfusion based on his labs?

Packed red blood cells and fresh frozen plasma (1:1 ratio) Platelets only Cryoprecipitate only Albumin solution

Correct! Packed red blood cells and FFP (1:1 ratio)

James has evidence of significant blood loss AND early coagulopathy:
• Low hemoglobin (112 g/L) → needs red cells for oxygen-carrying capacity
• Low fibrinogen (1.2 g/L) → needs clotting factors (FFP contains fibrinogen)
• Massive transfusion protocol calls for balanced component therapy
• 1:1:1 ratio (RBC:FFP:Platelets) reduces coagulopathy and mortality in trauma

Albumin (D) would expand plasma volume but not address oxygen-carrying capacity or coagulopathy.

5. What explains James' elevated lactate (4.2 mmol/L)?

Liver damage from trauma releasing lactate Excessive muscle activity during the accident Tissue hypoperfusion causing anaerobic metabolism and lactic acid production Respiratory acidosis from pain-induced hyperventilation

Correct! Tissue hypoperfusion causing anaerobic metabolism

Lactate elevation in shock indicates:
• Decreased tissue perfusion from hypovolemia
• Inadequate oxygen delivery to meet metabolic demands
• Cells switch to anaerobic glycolysis
• Pyruvate is converted to lactate (instead of entering Krebs cycle)
• Results in lactic acidosis (low pH, negative base excess)

Elevated lactate is a marker of tissue hypoperfusion and predictor of mortality in trauma. The goal is to normalize lactate through adequate resuscitation.

Bioscience Integration

Blood Components and Their Functions

James' blood loss affects all components:

Red Blood Cells (Hematocrit 34%): Carry hemoglobin for oxygen transport. Loss → tissue hypoxia, anaerobic metabolism
Plasma (55% of blood volume): Contains clotting factors, albumin, electrolytes. Loss → coagulopathy, volume depletion
Platelets (245 x10⁹/L): Form primary hemostatic plug. Currently adequate but consumption may occur
White Blood Cells (15.8 x10⁹/L): Elevated due to stress response (demargination and release from bone marrow)

Hematocrit calculation: (RBC volume / Total blood volume) × 100. Normal is 40-50% in men.

Compensatory Mechanisms in Hemorrhagic Shock

The body activates multiple compensatory systems:

Neural: Baroreceptor reflex → increased HR, vasoconstriction (shunts blood to vital organs)
Hormonal: RAAS activation → aldosterone increases Na+/water retention; ADH increases water reabsorption
Fluid shifts: Interstitial fluid moves into intravascular space (Starling forces)
Cellular: Increased oxygen extraction by tissues (decreased mixed venous O2 saturation)

These mechanisms maintain perfusion initially, but decompensation occurs when blood loss exceeds 30-40%.

Nursing Implications

Immediate: Large-bore IV access (2 lines), fluid resuscitation with warmed crystalloids or blood products
Monitoring: Vital signs q5-15min, urine output (goal >0.5ml/kg/hr), mental status, capillary refill
Interventions: Direct pressure on bleeding, limb immobilization, prepare for OR, blood product administration
Warmth: Prevent hypothermia (impairs coagulation) with warming blankets
Complications: Coagulopathy, acidosis, hypothermia ("lethal triad"), ARDS, multi-organ failure

Self-Assessment Questions

Review: Why does James have normal platelets but low fibrinogen?

Think about consumption vs. production...

Answer: Platelets are consumed in clotting at injury sites, but bone marrow can rapidly release stored platelets (causing the normal count). Fibrinogen is consumed faster than it can be synthesized by the liver, especially with ongoing bleeding and consumption coagulopathy. Fibrinogen has a longer half-life (4 days) and liver synthesis cannot keep up with massive consumption.

Apply: Calculate James' approximate blood volume and blood loss.

Use standard formulas for blood volume...

Answer: For adult males: ~70ml/kg. James weighs approximately 75kg (estimated):
• Total blood volume: 75kg × 70ml/kg = 5,250ml (~5L)
• Class III shock = 30-40% loss = 1,575-2,100ml
• This matches the paramedic estimate of 1500-2000ml at scene
• Remaining blood volume: ~3-3.5L (explaining the 34% hematocrit after hemodilution)

The Bleeding Patient

Learning Objectives