Eggena 6 Flashcards
the patient had severe
anemia
the patient’s anemia had resulted from
relatively slow bleeding into the GI tract which was responsible for producing black looking stools.
guaiac test
demonstrates the presence of occult blood in the specimen.
because blood loss had been gradual, the kidneys
had had ample time to retain extra salt and water and, thus, to keep the circulating blood volume normal.
the concentration of hemoglobin and the hematocrite were reduced because
formation of red blood cells and synthesis of hemoglobin could not keep pace with the loss of blood.
the oxygen content of his arterial blood was
reduced. The oxygen carrying capacity of blood was reduced by more than 1/2 and was only about 90% saturated because of age related changes in lung structure and the presence of edema fluid in the inferior lobes.
when the brain does not obtain the oxygen it needs, a person becomes
nervous, irritable, sleepless, dizzy and may faint. It also leads to muscle weakness, which are the major complaints of the man.
when oxygen demands of tissues are not met in anemia, vascular smooth muscle
in precapillary vessels relaxes and more blood flows to tissues as a compensatory response (autoregulation of blood flow)
with increased blood flow in anemia
tissues can be supplied with adequate oxygen even though less oxygen is extracted from each unit of blood.
the increased venous return to the heart leads to an
increase in cardiac ouput, which can be calculated by the Fick principle.
The fick principle of CO was
twice the normal resting cardiac output, so the man has compensated for a two fold reduction in oxygen carrying capacity of blood by doubling cardiac output.
While cardiac output was increased,
there is little or no reserve in cardiac output to meet the increased oxygen requirements of tissues on exertion, so that symptoms of feeling weak and faint typically appeared when the main walked or climbed a few stairs.
the twofold increase in cardiac output was due to
a reduction in the resistance of his peripheral circulation.
the reduction in peripheral resistance was due to
peripheral vasodilation and diminished blood viscosity. both an increase in diameter of vessels as well as a decrease in blood viscosity decreases the resistance to blood flow.
stroke volume =
SV = CO/HR
frank-starling law of the heart
an increase in venous return distends the ventricles more and causes more to be ejected. The greater the volume of blood ejected into the aorta, the higher the sysstolic blood pressure and pulse pressure.
pulse pressure is proportional to
SV/C
the compliance of arteries
decreases with advances. The reduction in arterial compliance together with an increase in stroke volume were responsible for the high systolic blood pressure.
the reduction in total peripheral resistance was primarily responsible for
low diastolic blood pressure.
the high pulse pressure was responsible for
the bounding forceful radial artery pulse and the capillary pulsations under his fingernails.
high output failure
failure of the heart even though it pumps more than the normal amount of blood. The left ventricle cannot handle the increase in preload (venous return) and fails to eject the usual 2/3 of its end diastolic volume.
left ventricular failure leads to
an increase in pulmonary capillary pressure and pulmonary edema.
pulmonary edema starts at the
base of the lungs where it is detected on asucultation as moist rales.
the patient stuggled for air when asked to lie down (orthopnea) because
lying flat causes a greater portion of his lungs than before to be beneath heart level, and his lungs became congested and difficult to expand.
