Oxygenation Flashcards
Blood is oxygenated through which mechanisms?
- Ventilation
- Perfusion
- Transport of respiratory gases
What controls the rate and depth of respiration in response to changing tissue oxygen demands?
- neural regulators
- chemical regulators
Which system provides the the transport mechanism to distribute oxygen to cells and tissues of the body?
cardiovascular system
Where does the exchange of respiratory gases occur?
between the environment and the blood
What is respiration?
the exchange of oxygen and carbon dioxide during cellular metabolism
What are the three steps in the process of oxygenation?
- Ventilation
- Perfusion
- Diffusion
What moves gases into and out of the lungs?
pressure changes
What causes air to flow into the lungs?
Intrapleural pressure becomes more negative, setting up a pressure gradient between the atmosphere and the alveoli.
Which muscles are used for inspiration?
- diaphragm
- intercostal muscles
note: these muscles contract to create a negative pleural pressure and increase the size of the thorax for inspiration.
What is the process of moving gases into and out of the lungs?
Ventilation
What is the major inspiratory muscle of respiration?
diaphragm
Which nerve innervates the diaphragm?
phrenic nerve
note: exists in the spinal cord at the fourth cervical vertebra.
What is the term that relates to the ability of the cardiovascular system to pump oxygenated blood to the tissues and return deoxygenated blood to the lungs?
Perfusion
How is inspiration stimulated?
Chemical receptors in the aorta
What is the chemical produced in the lungs to maintain the surface tension of the alveoli and keep them from collapsing?
Surfactant
What is the collapse of alveoli that prevents normal exchange of oxygen and carbon dioxide?
Atelectasis
Which observation of a patient’s breathing can indicate ventilatory fatigue, air hunger, or decreased lung expansion?
elevation of the patient’s clavicles during inspiration
What is the term for the ability of the lungs to distend or expand in response to increased intraalveolar pressure?
Compliance
How do diseases such as pulmonary edema, insterstitial and pleural fibrosis, and congenital or traumatic structural abnormalities such as kyphosis or fractured ribs effect respiratory compliance?
decreases compliance
What is the term for the increase in pressure that occurs as the diameter of the airway decreases from mouth/nose to alveoli?
Airway Resistance
What is tidal volume?
the amount of air exhaled after normal inspiration
What is residual volume?
the amount of air left in the alveoli after a full expiration
What is forced vital capacity?
the maximum amount of air that can be removed from the lungs during forced expiration.
What is the process for exchange of respiratory gases in the alveoli and the capillaries?
Diffusion
How does the thickness of the alveolar capillary membrane effect diffusion?
increased thickness impedes diffusion.
What are the three factors that influence the capacity of the blood to carry oxygen?
- The amount of dissolved oxygen in the plasma
- The amount of hemoglobin
- The tendency of hemoglobin to bind with oxygen
Which physiological process produces CO2
cellular metabolism
Which characteristics of respiration does the CNS control?
respiratory rate, depth, and rhythm
Which characteristics of respiration does the cerebral cortex regulate?
voluntary control of respiration (delivers impulse to the respiratory motor neurons by way of the spinal cord)
Which characteristics of respiration is controlled by chemicals?
rate and depth: changes in CO2, O2, H ions (pH)
stimulate the chemoreceptors located in the medulla, aortic body, and carotid body, which in turn stimulate neural regulators to adjust rate & depth.
What is stroke volume?
the volume of blood ejected from the ventricles during systole
How does hemorrhage and dehydration effect stroke volume?
decrease in volume = decrease in stroke volume
What is the Frank-Starling (Starling’s) law of the heart?
As the myocardium stretches, the strength of the subsequent contractions increases
What happens when the myocardium is stretched beyond the physiological limits of the heart?
Results in insufficient stroke volume
What does an insufficient stroke volume lead to?
back up in the pulmonary (left heart failure) or systemic (right heart failure) circulation
What is cardiac output?
the amount of blood ejected from the left ventricle
What is the normal CO in a healthy adult at rest?
4-6L/min
What is the term for the amount of blood in the left ventricle at the end of diastole?
Preload
What is the term for the resistance to left ventricular ejection?
Afterload
Which part of the Autonomic nervous system increases the rate of impulse generation and speed of transmission?
sympathetic
Which part of the Autonomic nervious system decreases the rate of impulse generation and speed of transmission?
parasympathetic
Where does the conduction system of the heart originate?
SA node
What are four factors that influence adequacy of circulation, ventilation, perfusion, and transport of respiratory gasses to the tissues?
- Physiological
- Developmental
- Lifestyle
- Environmental
How does anemia and inhalation of toxic chemicals effect respiratory function?
Decreases the oxygen-carrying capacity of blood by reducing the amount of available hemoglobin to transport oxygen.
What is the physiological response to hypoxemia?
The development of increased red blood cells (polycythemia)
What is the most common toxic inhalant that decreases the oxygen-carrying capacity of blood?
Carbon monoxide
how does CO toxicity effect oxygen carrying capacity?
Hemoglobin strongly binds with CO, creating a functional anemia.
What is the term for abnormally low circulating blood volume?
hypovolemia
How does the body adapt to significant fluid loss?
- peripheral vasoconstriction
- increased HR
- increased CO
What is FiO2?
fraction of inspired oxygen
What causes decreases in FiO2?
upper and lower airway obstruction, or hypoventilation
How does increased metabolic activity effect oxygen demand?
increases oxygen demand
How does the body adapt to increases in CO2?
increases rate and depth of respiration
Which patients are at a greater risk for hypoxemia?
patients with pulmonary diseases
What are the three primary alterations in respiratory functioning?
- hypoventilation
- hyperventilation
- hypoxia
What is the normal arterial CO2 tension (PaCO2) range?
35-45 mmHg
What is the normal arterial O2 tension (PaO2) range?
80-100 mmHg
What is the normal SpO2?
greater than or equal to 95%
What happens when alveolar ventilation is inadequate to meet the oxygen demand of the body or eliminate sufficient carbon dioxide?
Hypoventilation
What is the maximum 02 administration for a patient with COPD?
24% to 28% (1-3L/min)
What does excessive retention of carbon dioxide lead to?
respiratory acidosis and respiratory arrest
What are the initial symptoms of hypoventilation?
- mental status changes
- dysrhythmias
- potential cardiac arrest
What happens if hypoventilation is left untreated?
- status rapidly declines
- convulsions
- unconsciousness
- death
What is the state of ventilation in which the lungs remove carbon dioxide faster than it is produced by cellular metabolism?
Hyperventilation
Which 4 conditions induce hyperventilation?
- severe anxiety
- infection
- drugs
- acid/base imbalance
What does excessive ventilation of carbon dioxide lead to?
respiratory alkalosis
What are signs and symptoms of hyperventilation?
- rapid respirations
- sighing breaths
- numbness and tingling of hands/feet
- lightheadedness
- loss of consciousness
What is the term for inadequate tissue oxygenation at the cellular level?
Hypoxia
What are 6 possible causes of hypoxia?
- decreased hemoglobin
- diminished concentration of inspired oxygen
- inability of the tissues to extract oxygen from blood
- decreased diffusion of O2 from alveoli to the blood
- poor tissue perfusion with oxygenated blood
- impaired ventilation
What are the clinical signs and symptoms of hypoxia?
- apprehension
- restlessness
- inability to concentrate
- decreased LOC
- dizziness
- behavioral changes
How are vital signs affected by hypoxia?
- increased pulse rate
- increased rate/depth of respiration
What causes cyanosis?
presence of desaturated hemoglobin in capillaries
How does a nurse assess hypoxia via cyanosis?
central cyanosis as observed in the tongue, soft palate, and conjunctiva of the eye where blood flow is high
What does peripheral cyanosis indicate?
often result of vasoconstriction and stagnant blood flow
What is the term for a deviation from the normal sinus rhythm caused by electrical impulses that do not originate from the SA node?
dysrhythmias
How are disrhythmias classified?
By cardiac response and site of impulse origin.
What makes atrial fibrillation irregular?
multiple pacemaker cites and the unpredictable conduction to the ventricles
What are abnormal impulses originating above the ventricles called?
supraventricular dysrhythmias
What is the sudden, rapid onset of tachycardia originating from above the AV node called?
Paroxysmal supraventricular tachycardia
What are the disrhythmias caused by an ectopic site of impulse formation within the ventricles called?(2)
- Ventricular tachycardia
- Ventricular fibrillation
Why is ventricular tachycardia life-threatening?
decreased CO and the potential to deteriorate into ventricular fibrillation or sudden cardiac death
What are clinical findings of left-sided heart failure?
- crackles at base of lungs
- hypoxia
- dyspnea during exertion
- cough
- paroxysmal nocturnal dyspnea
What are clinical findings of right-sided heart failure?
- weight gain
- distended neck veins
- hepatomegaly and splenomegaly
- dependent peripheral edema
What are the two types of impaired valvular function?
- stenosis (hardening)
- regurgitation (impaired closure)
What are two common outcomes of myocardial ischemia?
- angina pectoris
- MI
Why are infants and toddlers at risk for upper respiratory tract infections?
- frequent exposure to other children
- immature immune system
- exposure to secondhand smoke
What are the 4 characteristics of chest pain that a nurse needs to assess for?
- location
- duration
- radiation
- frequency
What is the term for an abnormal condition in which a person must sit or stand to breathe comfortably?
orthopnea
What is hemoptysis?
blood sputum
What are characteristics of abnormal sputum?
- green
- bloody (hemoptysis)
- think/thin
- foul odor
- increased/decreased
If hemoptysis is present, where are likely sources of blood?
- upper respiratory tract
- sinus drainage
- GI tract (hematemesis)
How can pH testing help to determine the source of bloody sputum?
blood from upper respiratory/sinus will have alkaline pH, blood from GI will be acidic.
What are the most common sources of environmental exposure in the home?
- cigarette smoke
- CO
- radon
What do clubbed nails often indicate?
- prolonged oxygen deficiency
- endocarditis
- congenital heart defects
what is the term for the when the chest wall contracts during inspiration and expands during exhalation?
paradoxical breathing (asynchronous breathing)
What is the term for an increased rate and depth of respirations?
Kussmaul respiration
What is the term for the absence of respirations for a period of time?
apnea
What is the term for when the respiratory pattern has periods of apnea followed by periods of deep breathing and then shallow breathing followed by more apnea?
Cheyne-Stokes respiration
What causes Cheyne-Stokes respiration?
decreased blood floow or injury to the brainstem
What is the cause of xanthelasma (yellow lesions on the eyelids)?
hyperlipidemia
What is the cause of corneal arcus (whitish opaque ring around junction of cornea and sclera)?
Abnormal finding in young to middle-age adults with hyperlipidemia (normal finding in older adults with arcus senilis)
What is the cause of pale conjunctivae?
anemia
What is the cause of cyanotic conjunctivae?
hypoxemia
What is the cause of petechiae on conjunctivae?
fat embolus or bacterial endocarditis
What is the cause of cyanotic mucous membranes?
hypoxia
What is the cause of pursed-lip breathing
associated with chronic lung disease
What is the cause of neck vein distention?
associated with right-sided heart failure
What is the cause of flaring nares?
air hunger, dyspnea
What is the cause of chest retractions?
increased WOB, dyspnea
What is the cause of chest asymmetry?
chest wall injury
What is the cause of peripheral cyanosis?
vasoconstriction and diminished blood flow
What is the cause of central cyanosis?
hypoxemia
What is the cause of decreased skin turgor?
dehydration (normal in older adults d/t decreased skin elasticity)
What is the cause of dependent edema?
associated with right and left-sided heart failure
What is the cause of periorbital edema?
associated with kidney disease
What is the cause of cyanosis in the fingertips and nail beds?
decreased CO or hypoxia
What is the cause of splinter hemorrhages in the nail beds?
bacterial endocarditis
Why are cardiac enzymes tested?
To diagnose acute myocardial infarcts
What is the normal range for the cardiac enzyme creatinine kinase (CK)?
male: 55-170 units/L
female: 30-135 units/L
Why are cardiac troponins tested?
value elevates as early as 3 hours after myocardial injury. Value for cardiac troponin I often remains elevated for 7-10 days; value for cardiac troponin T for 10-14 days
What is the normal range for cardiac troponin I?
<0.03 ng/mL
What is the normal range for cardiac troponin T?
<0.1 ng/mL
Why is myoglobin tested?
Early index of damage to myocardium in myocardial infarction or reinfarction. increases within 3 hours.
What is the normal range for myoglobin?
<90mcg/L
What is the normal range for serum potassium?
3.5-5 mEq/L
Patients taking ACE inhibitors are at risk for an increase in which electrolyte?
potassium (hyperkalemia)
What is the normal range for fasting cholesterol?
<200mg/dL
What is the normal range for LDLs?
<130
What is the normal range VLDLs (very low density lipoproteins)?
7-32mg/dL
What is the normal range for HDLs?
male: >45 mg/dL
female: >55 mg/dL
What is the normal range for triglycerides?
male: 40-160 mg/dL
female: 35-135 mg/dL
What is the normal range for pH?
7.35-7.45
What is the normal range for PCO2?
35-45 mmHg
What is the normal range for HCO3?
21-28 mEg/L
What is the normal range for PO2?
80-100 mmHg
What is the normal range for SaO2 saturation?
> 95%
What is the normal range for Base excess?
0 ± 2 mEq/L
At what O2 rate is humidification necessary?
> 4L/min
What is the procedure that adds moisture or medication to inspired air by mixing particles of varying sizes with the air?
Nebulization
How does a nurse evaluate the effectiveness of coughing?
- sputum expectoration
- patient’s report of swallowed sputum
- clearing of adventitious lung sounds
What are the 4 coughing techniques
- deep breathing and coughing
- cascade cough
- huff cough
- quad coughing
What are the 3 types chest physiotherapy (CPT) techniques?
- postural drainage
- chest percussion
- vibration
What are two examples of NPPV?
NPPV= noninvasive positive-pressure ventilation
- Continuous positive airway pressure (CPAP)
- Bilevel airway presure (BiPAP)
Which patients are treated with CPAP?
- obstructive sleep apnea
- heart failure
- preterm infants with underdeveloped lungs
What is the term for a catheter inserted through the thorax to remove air and fluids from the pleural space?
chest tube
What are chest tubes commonly used to treat?
pneumothorax or hemothorax to promote lung reexpansion
What is the term for a collection of air in the pleural space?
pneumothorax
What causes a pneumothorax?
The loss of negative intrapleural pressure which causes the lung to collapse
What does PEEP stand for?
Positive end-expiratory pressure
What is the term for the accumulation of blood and fluid in the pleural cavity between the parietal and visceral pleura?
hemothorax
What is the most serious tracheostomy complication?
airway obstruction
What is the junction where the trachea branches into the right and left mainstem bronchi?
carina