anemia post hemorrage

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ANEMIA POST HEMORRAGE

HEMATOLOGY – ONCOLOGY DIVISION



DEFINITION

Anemia is characterized by a reduction in the

number of circulating

• red blood cells (RBCs)

• the amount of hemoglobin

or• the volume of packed red blood cells (hematocrit)



CLASSIFICATION

Anemia is classified based on occurrence

as:• Acute

• Chronic



TERMINOLOGY

• Acute anemia denotes a precipitous drop in

the RBC population due to hemolysis or acute

hemorrhage



ETIOLOGY OF ACUTE ANEMIA

In the emergency department

(ED)

acute hemorrhage is by far themost common etiology



• Decreased hemoglobin oxygen affinity

• Redistribution of blood flow

• Increase cardiac output

Physiologic compensation for decrease RBC mass



Increased oxygen extraction of anemic blood by the tissues produces

Increased concentration of deoxyhemoglobin in the rbc

The production of 2,3-diphosphoglycerate (2,3-DPG).

2,3-DPG shifts the hemoglobin-oxygen dissociation curve to the right,

thus allowing the tissues to more easily strip the hemoglobin of its precious

electron-accepting cargo

stimulates

Decrease hemoglobin oxygen affinity



Decrease hemoglobin oxygen affinity



• In anemia selective vasoconstriction of blood vessels subserving certain nonvital

areas allows more blood to flow into critical areas

• The main donor sites who sacrifice their aerobic lifestyle are the skin and kidneys

• Shunting of blood away from cutaneous sites is the mechanism behind the clinical

finding of pallor, a cardinal sign of anemia

• Although the kidney can hardly be thought of as a nonvital area, it receives (in the

normal state) much more blood flow than is needed to meet its metabolic

requirements

• Although (by definition) total body red cell mass is decreased in anemia, in the

chronically anemic patient the total blood volume paradoxically is increased,

due to increased plasma volume

• It is as if the body were trying to make up in blood quantity what it lacks in quality

Redistribution of blood flow



• The heart can respond to tissue hypoxia by increased cardiac output

• The increased output is matched by decreased peripheral vascular resistance

and decreased blood viscosity (thinner blood flows more freely than thick

blood), so that cardiac output can rise without an increase in blood pressure

• Generally, anemia must be fairly severe (hemoglobin < 7 g/dL) before

cardiac output rises

Increased cardiac output



HOW THE BODY IS AFFECTED BY ANEMIA



Assume that the hemoglobin level drops from 15 gm/dL to 5 gm/dL

This patient will be at risk of hypotensive shock (the blood pressure dropping

below normal values)

This shock phenomenon can be initiated with a blood loss of 15% to 25%

The patient will experience and even complain of

[1] tachycardia

[2] tachypnea[3] pallor

[4] diaphoresis

[5] oliguria

[6] apprehension

[7] restlessness

Intense cutaneous vasoconstriction is the rule and the patient will probably

not recognize this



Hemorrhage

Blood loss

Hypovolemia

Shock



Shock classification

Class I (<15% blood loss)

- mild tachycardia may be present

but

- blood pressure is normal.




Class II (15-30% blood loss)

• tachycardia

• tachypnea and

• a decreased pulse pressure are seen




Class III (30-40% blood loss)

• always leads to a measurable decrease in bloodpressure as well as a significant tachycardia

and

• a narrow pulse pressure




Class IV (40% and greater blood loss)

• leads to patient demise unless prompt resuscitative

measures are taken

• Marked tachycardia and significantly decreased blood

pressure are common findings.

• Blood loss greater than 50% leads to loss of pulse and

blood pressure.



Management

• Emergency Department Care

• Evaluate ABCs and immediately treat any life-threateningconditions

• Crystalloid is the initial fluid of choice



Management

Acute anemia due to blood loss

– Monitor with pulse oximetry, cardiac monitor, and a

sphygmomanometer

– Provide supplemental oxygen via nasal cannula or face

mask

– Establish 2 large-bore intravenous lines and rapidly infuse

1-2 L of crystalloids while monitoring the patient carefully

for signs and symptoms of iatrogenic congestive heart

failure



Management


– Blood transfusions for patients who remain hypotensive

after 2 L of crystalloid infusion for young healthy patientswith a hematocrit level below 20 or for elderly patients

with a hematocrit level below 30

– Vasopressors are relatively contraindicated in thetreatment of hypovolemic shock



Management


– Obtain fresh frozen plasma (FFP), coagulation factors, and

platelets, if indicated

– Patients with hemophilia should have samples of the

deficient factors sent for measurement

– Once the patient is stabilized, begin specific measures to

treat the underlying cause of bleeding



Blood transfusion in hemorrhagic anemia

• Blood component

• Complete whole blood if

loss blood volume > 50 % of body blood volume

anemia post hemorrage

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