Case Study 3: Blanche Devereaux is a 78-year-old widow who was brought to the em

Question

Case Study 3:

Blanche Devereaux is a 78-year-old widow who was brought to the emergency room one evening by her sister. Earlier in the day, she had seen bright red blood in her stool. She continued with her daily activities. However, the bleeding continued all day. By dinnertime, she could no longer ignore it. Blanche takes aspirin, as needed, for arthritis, sometimes up to 12 tablets daily. In the emergency room, she was light-headed and her skin was pale and cool to the touch. Her hematocrit was 26% (normal for women, 35%-45%). The ER doctor ordered orthostatic vital signs. Below are the results of the test:

Measurement

Supine

Standing

Blood Pressure

88/60

74/46

Heart Rate

106 bpm

130 bpm

1. What is the definition of circulatory shock? What are some causes of circulatory shock?

2. After blood loss, what is the fundamental problem in shock? Why does shock occur due to loss of blood?

3. Calculate Mrs. Devereaux’s pulse pressure and mean arterial pressure while supine and standing.

4. What was the compensatory mechanism that leads to her heart rate being fast in both positions?

Measurement

Supine

Standing

Blood Pressure

88/60

74/46

Heart Rate

106 bpm

130 bpm

Explanation / Answer

1. What is the definition of circulatory shock? What are some causes of circulatory shock?

Circulatory shock, commonly known as shock, is a life-threatening medical condition of low blood perfusion to tissues resulting in cellular injury and inadequate tissue function. The typical signs of shock are low blood pressure, rapid heart rate, and signs of poor end-organ perfusion (i.e.: low urine output, confusion, or loss of consciousness).

There are three stages of shock: Stage I (also called compensated, or nonprogressive), Stage II (also called decompensated orprogressive), and Stage III (also called irreversible).

In Stage I of shock, when low blood flow (perfusion) is first detected, a number of systems are activated in order tomaintain/restore perfusion. The result is that the heart beats faster, the blood vessels throughout the body become slightlysmaller in diameter, and the kidney works to retain fluid in the circulatory system. All this serves to maximize blood flow to themost important organs and systems in the body. The patient in this stage of shock has very few symptoms, and treatment cancompletely halt any progression.

In Stage II of shock, these methods of compensation begin to fail. The systems of the body are unable to improve perfusionany longer, and the patient's symptoms reflect that fact. Oxygen deprivation in the brain causes the patient to becomeconfused and disoriented, while oxygen deprivation in the heart may cause chest pain. With quick and appropriate treatment,this stage of shock can be reversed.

In Stage III of shock, the length of time that poor perfusion has existed begins to take a permanent toll on the body's organsand tissues. The heart's functioning continues to spiral downward, and the kidneys usually shut down completely. Cells inorgans and tissues throughout the body are injured and dying. The endpoint of Stage III shock is the patient's death.

2.After blood loss, what is the fundamental problem in shock? Why does shock occur due to loss of blood?

Shock is caused by three major categories of problems: cardiogenic (meaning problems associated with the heart'sfunctioning); hypovolemic (meaning that the total volume of blood available to circulate is low); and septic shock (caused byoverwhelming infection, usually by bacteria).

Cardiogenic shock can be caused by any disease, or event, which prevents the heart muscle from pumping strongly andconsistently enough to circulate the blood normally. Heart attack, conditions which cause inflammation of the heart muscle(myocarditis), disturbances of the electrical rhythm of the heart, any kind of mass or fluid accumulation and/or blood clot whichinterferes with flow out of the heart can all significantly affect the heart's ability to adequately pump a normal quantity of blood.

Hypovolemic shock occurs when the total volume of blood in the body falls well below normal. This can occur when there isexcess fluid loss, as in dehydration due to severe vomiting or diarrhea, diseases which cause excess urination (diabetesinsipidus, diabetes mellitus, and kidney failure), extensive burns, blockage in the intestine, inflammation of the pancreas(pancreatitis), or severe bleeding of any kind.

Septic shock can occur when an untreated or inadequately treated infection (usually bacterial) is allowed to progress. Bacteriaoften produce poisonous chemicals (toxins) which can cause injury throughout the body. When large quantities of thesebacteria, and their toxins, begin circulating in the bloodstream, every organ and tissue in the body is at risk of their damagingeffects. The most damaging consequences of these bacteria and toxins include poor functioning of the heart muscle; wideningof the diameter of the blood vessels; a drop in blood pressure; activation of the blood clotting system, causing blood clots,followed by a risk of uncontrollable bleeding; damage to the lungs, causing acute respiratory distress syndrome; liver failure;kidney failure; and coma.

Initial symptoms of shock include cold, clammy hands and feet; pale or blue-tinged skin tone; weak, fast pulse rate; fast rate ofbreathing; low blood pressure. A variety of other symptoms may be present, but they are dependent on the underlying cause of shock.

3. Calculate Mrs. Devereaux’s pulse pressure and mean arterial pressure while supine and standing.

use the formula

MAP = [(2 x diastolic)+systolic] / 3    for Mean arterial pressure

Supine:[(2 x 60)+80] / 3 =69.33mmHg

Standing:[(2 x 46)+74] / 3 =55.33mmHg

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