Oxygenation Flashcards
The exchange of respiratory gases occurs
between the environment and the blood.
Respiration is
the exchange of oxygen and carbon dioxide during cellular metabolism.
supply the oxygen demands of the body.
The cardiac and respiratory systems
control the rate and depth of respiration in response to changing tissue oxygen demands.
Neural and chemical regulators
The process of moving gases into and out of the lungs
Ventilation
The ability of the cardiovascular system to pump oxygenated blood to the tissues and return deoxygenated blood to the lungs
Perfusion
Exchange of respiratory gases in the alveoli and capillaries
Diffusion
Work of breathing =
The effort required to expand and contract the lungs.
Surfactant =
Chemical produced in the lungs to maintain the surface tension of the alveoli and keep them from collapsing.
Atelectasis =
Collapse of the alveoli that prevents the normal exchange of oxygen and carbon dioxide.
active process, stimulated by chemical by chemical receptors in the aorta
Inspiration
passive process that depends on the elastic recoil properties of the lungs, requiring little or no muscle work
Expiration
Compliance =
ability of the lungs to distend or expand in response to increased intraalveolar pressure
Airway resistance =
increase in pressure that occurs as the diameter of the airway diameter by bronchoconstriction
Oxygen transport
Lungs and cardiovascular system
Depends on lungs (ventilation), blood flow to the lungs and tissues (perfusion), rate of diffusion, and oxygen-carrying capacity
Pulmonary circulation
Moves blood to and from the alveolar capillary membranes for gas exchange
Carbon dioxide transport
Diffuses into red blood cells and is rapidly hydrated into carbonic acid
Tidal volume =
amount of air exhaled after normal inspiration
Residual volume =
the amount of air left in the aveoli after full expiration
Forced vital capacity (FVC):
the maximum amount of air that can be removed from the lungs during forced expiration
Hemoglobin carries
O2 and CO2
Neural regulation
- Central nervous system controls the respiratory rate, depth, and rhythm.
- Cerebral cortex regulates the voluntary control of respiration.
Chemical regulation
- Maintains the rate and depth of respirations based on changes in the blood concentrations of CO2 and O2, and in hydrogen ion concentration (pH)
- Chemoreceptors sense changes in the chemical content and stimulate neural regulators to adjust.
Cardiovascular Physiology involves
delivery of deoxygenated blood (blood high in carbon dioxide and low in oxygen) to the right side of the heart and then to the lungs, where it is oxygenated.
Cardiovascular Physiology: Oxygenated blood then travels
from the lungs to the left side of the heart and the tissues.
Myocardial pump
- Two atria and two ventricles
- As the myocardium stretches, the strength of the subsequent contraction increases (Starling’s law).
Coronary artery circulation
Coronary arteries supply the myocardium with nutrients and remove wastes.
Myocardial blood flow
Unidirectional through four valves
S1: mitral and tricuspid close
S2: aortic and pulmonic close
Systemic circulation
Arteries and veins deliver nutrients and oxygen and remove waste products.
Cardiac output
Amount of blood ejected from the left ventricle each minute
Stroke volume
Amount of blood ejected from the left ventricle with each contraction
Cardiac output (CO) =
Stroke volume (SV) × Heart rate (HR)
Preload
End-diastolic pressure
Afterload
Resistance to left ventricular ejection
Autonomic nervous system
Influences the rate of impulse generation and the speed of conduction pathways
Sympathetic nervous system
Increases the rate of impulse generation and impulse transmission and innervates all parts of the atria and ventricle
Parasympathetic system
Decreases the rate and innervates atria, ventricles, and sinoatrial and atrioventricular nodes
Conduction system
Originates with the sinoatrial (SA) node or pacemaker and is transmitted to the atrioventricular (AV) node, bundle of His, and Purkinje fibers
An electrocardiogram (ECG) reflects
the electrical conduction system of the heart.
Physiological factors affecting Oxygenation
Decreased oxygen-carrying capacity
Hypovolemia
Decreased inspired oxygen concentration
Increased metabolic rate
Conditions affecting chest wall movement
Pregnancy, obesity, neuromuscular disease, musculoskeletal abnormalities, trauma, CNS alterations
Other factors
Influences of chronic diseases
Hyperventilation
Ventilation in excess of that required to eliminate carbon dioxide produced by cellular metabolism
Hypoventilation
Alveolar ventilation inadequate to meet the body’s oxygen demand or to eliminate sufficient carbon dioxide
Hypoxia
Inadequate tissue oxygenation at the cellular level
Cyanosis
Blue discoloration of the skin and mucous membranes
Disturbances in conduction
Caused by electrical impulses that do not originate from the SA node (dysrhythmias)
Altered cardiac output
Insufficient volume is ejected into the systemic and pulmonary circulation; the result of left-sided or right-sided heart failure
Impaired valvular function
Acquired or congenital disorder of a cardiac valve by stenosis or regurgitation
Myocardial ischemia
Coronary artery flow to the myocardium insufficient to meet myocardial oxygen demands; results in angina, myocardial infarction (MI) and/or acute coronary syndrome (ACS)
Angina pectoris: transient imbalance between myocardial oxygen supply and demand
Cardiopulmonary rehabilitation
Controlled physical exercise; nutrition counseling; relaxation and stress management; medications; oxygen; compliance; systemic hydration
Restorative and Continuing Care
Cardiopulmonary rehab
Respiratory muscle training
Breathing exercises
Respiratory muscle training prevents
respiratory failure in patients w/ COPD
Breathing exercises
Pursed-lip breathing: deep inspiration and prolonged expiration through pursed lips to prevent alveolar collapse
Diaphragmatic breathing: for patient w/ pulmonary disease, post-op patients, and women in labor to promote relaxation and provide pain control
Ask about
Degree of breathlessness If distance ambulated without fatigue has increased Rating the breathlessness from 0 to 10 Which interventions reduce dyspnea Frequency of cough and sputum production
Perform
Observe respiratory rate before, during, and after any activity.
Assess any sputum produced.
Auscultate lung sounds for improvement in adventitious sounds.
