Chapter 40- Oxygenation Flashcards
Ventilation:
Process of moving gases into and out of the lungs
Major inspiratory muscle of respiration:
Diaphragm
Innervated by the phrenic nerve
Perfusion:
ability of the cardiovascular system to pump oxygenated blood to the tissues and return deoxygenated blood to the lungs
Work of breathing:
effort required to expand and contract the lungs
Inspiration is a _____ process:
active process stimulated by chemical receptors in the aorta
Expiration is a ___ process
passive process that depends on the elastic recoil properties of the lungs, requiring little to no muscle work
Atelectasis:
collapse of the alveoli that prevents normal exchange of oxygen and carbon dioxide
Stroke volume:
Volume of blood ejected from the ventricles
Cardiac output:
amount of blood ejected from the left ventricle each minute
Cardiac output equation:
Stroke volume X heart rate
Preload:
amount of blood in the left ventricle at the end of diastole, often referred to as end-diastolic volume
Afterload:
resistance to left ventricular ejection
myocardial contractility:
affects stroke volume and cardiac output
poor ventricular contraction decreases the amount of blood ejected
Four factors that influence adequacy of circulation, ventilation, perfusion and transport of respiratory gases to the tissues:
physiological
developmental
lifestyle
environmental
Hypovolemia:
extracellular fluid loss and reduced circulating blood volume
Conditions affecting chest wall movement:
pregnancy
obesity
musculoskeletal abnormalities
trauma
neuromuscular diseases
CNS alterations
3 primary alterations:
hypoventilation
hyperventilation
hypoxia
Hypoxemia:
refers to a decrease in the amount of arterial oxygen
Goal of ventilation is to:
normal arterial carbon dioxide tension between 35 mm Hg to 45 mm Hg
normal arterial oxygen tension: 80-100 mm Hg
Hypoventilation:
occurs when alveolar ventilation is inadequate to meet the oxygen demand of the body or eliminate sufficient carbon dioxide
BODY RETAINS CARBON DIOXIDE
Hyperventilation:
state of ventilation in which the lungs REMOVE CARBON DIOXIDE FASTER than it is produced by cellular metabolism
Hypoxia:
inadequate tissue oxygenation at the cellular level
results from a deficiency in oxygen delivery or oxygen use at cellular level
Causes of hypoxia include:
decreased hemoglobin level and lowered oxygen carrying capacity of blood
diminished concentration of inspired oxygen which occurs at high altitudes
inability of the tissues to extract oxygen from the blood as with cyanide poisoning
decreased diffusion of oxygen from the alveoli to the blood as in pneumonia
poor tissue perfusion with oxygenated blood as with shock
impaired ventilation as with multiple rib fractures or chest trauma
Clinical signs and symptoms of hypoxia:
apprehension
restlessness
inability to concentrate
decreased level of consciousness
dizziness
behavioral changes
patient with hypoxia is unable to lie flat and appears both fatigued and agitated
