(1) Intestines. Capillaries surrounding the intestines absorb fluids and
nutrients from the intestines. Before returning to the heart, blood travels to the liver
through the hepatic portal vein. In the liver, some of the nutrients are removed and
stored for future use. The liver also removes bacteria and other types of unwanted
substances from the blood. After passing through the liver, blood returns to the inferior
vena cava through the hepatic vein.
(2) Kidneys. Some of the blood flows through the kidneys. The kidneys act
as filters and remove most of the waste products contained in the blood. The major
waste product removed is urea. The kidneys expel urea and other waste products in
the form of urine.
Section II. GENERAL CONSIDERATIONS REGARDING CARDIAC ARREST
CARDIAC ARREST AND HEART ATTACK
It is important to understand the difference between cardiac arrest and a heart
attack. Cardiac arrest (sudden death) is a result of the sudden and unexpected
cessation of respiration and circulation. That is, the casualty stops breathing, and his
heart stops beating. A heart attack is caused by a blockage of one or more of the
coronary arteries (arteries which provide the heart muscles with oxygen-rich blood).
PRIMARY CAUSES OF CARDIAC ARREST
Cardiac arrest (cessation of the heartbeat) may occur for a number of reasons.
Sixty percent of cardiac arrest cases occur as a result of cardiovascular diseases which
include progression of myocardial infarction (death of myocardial cells due to an
interrupted blood supply) and progression of heart rhythm disorders. Respiratory
disease accounts for fifteen percent of cardiac arrest cases, and digestive and
urogenital disease account for another seven percent of cardiac arrest cases. These
miscellaneous cases make up the remaining three percent: hyperkalemia (abnormally
high potassium concentration in the blood); electrical burns; metabolic disorders such
as acidosis (disease resulting from accumulation of acid or depletion of alkaline in the
blood and body tissues); trauma to the chest; pulmonary embolism (pulmonary artery or
a branch being closed); intracerebral hemorrhage (bleeding in the cerebrum); and
coronary artery spasm. When cardiac arrest occurs, oxygen is not circulated, and the
body uses the oxygen stored in the vital organs in seconds.
MAJOR RISK FACTORS OF CARDIAC ARREST
a. Statistics. Statistics indicate that cardiac arrest is more likely to occur in
these groups of individuals: