Oxygenation ch. 40 Flashcards
what is the amount of air inspired and expired with each breath, in milliliters, and is usually set by the patient’s ideal body weight (5 to 8 mL/kg).
tidal volume
what is the purpose of using the incentive spirometer.
helps minimize the chance of fluid build-up in the lungs and to help reduce the incidence of postoperative pulmonary atelectasis.The patient breathes in from the device as slowly and as deeply as possible, then holds his/her breath for 2-6 seconds. This provides back pressure which pops open alveoli.
what structures create a negative pleural pressure and increase the size of the thorax for inspiration.
the contraction of the diaphragm and external intercostal muscles.
what acid-base status increases the ability of hemoglobin to release oxygen to the tissues
acidemia
what acid-base status decreases the ability of hemoglobin to release oxygen to the tissues.
Alkalemia
what are some Causes of hypoxia include
1) a decreased hemoglobin level and lowered oxygen-carrying capacity of the blood; (2) a diminished concentration of inspired oxygen, which occurs at high altitudes; (3) the inability of the tissues to extract oxygen from the blood, as with cyanide poisoning or alkalemia; (4) decreased diffusion of oxygen from the alveoli to the blood, as in pneumonia or atelectasis; (5) poor tissue perfusion with oxygenated blood, as with shock,; and (6) impaired ventilation, as with multiple rib fractures or chest trauma.
why will administering high levels of oxygen extinguish the stimulus to breathe in COPD.
In these patients it is the change in the oxygen level that stimulates changes in ventilation as opposed to In a healthy person’s lungs, the chemoreceptors are sensitive to small changes in carbon dioxide levels instead.
what nerve controls the function of the diaphragm
phrenic nerve
where does the phrenic nerve exit on the spinal cord.
at the fourth cervical vertebra
The major inspiratory muscle of respiration is what
diaphragm
what is surfactant
is the chemical produced in the lungs to maintain the surface tension of the alveoli and keep them from collapsing
patients with COPD,especially emphysema, frequently use what muscles to increase lung volume.
Accessory muscles.
what is compliance
is the ability of the lungs to distend or expand in response to increased intraalveolar pressure.
in what kinds of diseases would you see decreased compliance in?
Pulmonary edema, interstitial and pleural fibrosis, and congential or traumatic structural abnormalities such as kyphosis or fractured ribs.
what does expiration depend on?
the elastic recoil properties of the lungs.
How does advanced COPD affect respirations?
It causes loss of the elastic recoil of the lungs and thorax.
what is Atelectasis?
it is the collapse of the alveoli that prevents normal exchange of oxygen and carbon dioxide.
patients with certain pulmonary diseases have decreased production of what chemical from the lungs and this sometimes develops into what adverse condition
surfactant, and atelectasis.
what are normal lung values determined by?
age, gender, and height.
what does the elevation of the patient’s clavicles during inspiration indicate
use of accessory muscles, ventilation fatigue, air hunger, or decreased lung expansion.
what is the term for maximum amount of air that can be removed from the lungs during forced expiration.
forced vital capacity
the thickness of the alveoli affects the rate of what
diffusion of respiratory gases.
why does increased thickness of the alveolar membrane impedes diffusion?
Because gases take longer to transfer across the membrane.
what types of respiratory conditions cause thickened alveolar membranes.
pulmonary edema, pulmonary infiltrates (pneumonia) or pulmonary effusion.
what are the three things that influences the capacity of the blood to carry oxygen.
- The amount of the dissolved oxygen in the plasma, 2. The amount of hemoglobin, 3. and the tendency of hemoglobin to bind with oxygen.
the more stretch on the ventricular muscle, the greater the contraction and the greater the stoke volume.
Frank-starling law of the heart.
when does starling law not apply
in the diseased heart (cardiomyopathy, or MI)
During ventricular diastole what valves open and cause blood flow from the higher pressure atria into the ventricles,
Mitral and tricuspid.
what happens to the valves during ventricular systole
ventricular pressure rises and closes the mitral and tricuspid valves. semilunar valves open (aortic and pulmonic) valves open,and blood flows form the ventricles into the aorta and pulmonary artery.
which coronary artery has the most abundant supply and feeds the more muscular left ventricular myocardium.
Left anterior descending coronary artery.
what is the normal cardiac output in the healthy adult at rest
4 to 6 L/min
what factors affect stroke volume
The amount of blood in the left ventricle at the end of diastole (preload), the resistance to left ventricular ejection (afterload), and myocardial contractility.
what is a good clinical measure of afterload
the diastolic aortic pressure.
what is the process of transporting carbon dioxide out of the body.
1.carbon dioxide diffuses into red blood cells and is rapidly hydrated into carbonic acid. 2. The carbonic acid then dissociates into hydrogen and bicarbonate ions. 3. Hemoglobin buffers the hydrogen ion, and the Bicarb diffuses into the plasma. 4. reduced hemoglobin (Deoxyhemoglobin) combines with carbon dioxide, and the venous blood transports the majority of carbon dioxide back to the lungs to be exhaled.
What is preload?
It is the end-diastolic volume
what is afterload?
Is the resistance to left ventricular ejection. the heart works harder to overcome the resistance so blood can be fully ejected from the left ventricle.
what does hypertension do to afterload
increases it. increasing cardiac workload.
what three conditions cause extracellular fluid loss and reduced stroke volume. and what would the medical term be for describing decreased fluid volume be called.
hemorrhaging, shock, dehydration (hypovolemia)
what is the primary pathological factor in right sided- heart failure and what happens during it.
elevated pulmonary vascular resistance as a result from pulmonary diseases. As the PVR continues to rise, the right ventricle works harder, and the oxygen demand of the heart increases. As the failure continues, the amount of blood ejected from the right ventricle declines, and blood beings to “back up” in the systemic circulation.
what causes S1 sounds
closure of mitral and tricuspid valves
what causes S2 sounds
closure of semilunar valves (aorta and pulmonic)
how does heart rate affect cardiac output
because of the relationship between rate and diastolic filling time.
what will a sustained heart rate greater than 160 beat/min affect cardiac output
diastolic filling time decreases, decreasing stoke volume and cardiac output.
what part of the nervous system influences the rate of impulse generation and the speed of transmission through the conductive pathway and the strength of atrial and ventricular contractions.
the autonomic nervous system.
what nerve fibers increase the rate of impulse generation and speed of transmission.
sympathetic
What nerve fibers originating from the vagus nerve decrease the rate of the heart.
Parasympathetic
what does the AV node do
It assists atrial empty by delaying the impulse before transmitting it through the bundle of his and the ventricular purkinje fibers.
what does the qt interval indicate
it represents the time needed for ventricular depolarization and repolarization.
what is the normal QT interval?
0.12 to 0.42 this interval varies inversely with changes in heart rate.
what changes in electrolyte values increase the QT interval
hypocalcemia
what kinds of drugs increase the QT interval
Disopyramide (norpace) or amiodarone (Cordarone)
shortening of the QT interval occurs when?
With digitalis therapy, hyperkalemia, and hypercalcemia.
respiratory disorders usually include what three conditions
hyperventilation, hypoventilation, and hypoxia.
Cardiac disorders include what conditions?
disturbances in conduction (arrhythmias, heart blocks) impaired valvular function, myocardial hypoxia, cardiomyopathic conditions, and peripheral tissue hypoxia.
what two conditions decrease the oxygen carrying capacity of blood by reducing the amount of available hemoglobin to transport oxygen
anemia and toxic substances.
what is anemia the result of
Decreased hemoglobin production( such as aplastic anemia or iron deficiency anemia), increased red blood cell destruction (hemolysis), and/or blood loss (hemorrhage).
what are the symptoms of anemia
fatigue, decreased activity tolerance, increased breathlessness, increased heart rate (to compensate for the lack of oxygen circulating), and pallor (especially seen in the conjunctiva of the eye).
what is the physiological response to chronic hypoxemia (low oxygen in the blood).
is the development of increased red blood cells (polycythemia). This is a adaptive response of the body to increase the amount of hemoglobin and the available oxygen-binding sites.