[N11] LEC 4: Oxygenation

Oxygen

Oxygen

odorless gas that constitutes approximately 21% of the air we breathe

Cellular metabolism

produces carbon dioxide, which must be eliminated from the body to maintain normal acid-base balance.

respiratory system

provides the essential first process in this integrated system, that is, movement and transfer of gases between the atmosphere and the blood

1. Pulmonary Ventilation

2. Alveolar-capillary gas exchange

3. Transport of oxygen and carbon dioxide (between the tissues and the lungs)

4. Systemic diffusion (Movement of oxygen and carbon dioxide between the systemic capillaries and the tissues)

Four components/processes of respiration

Ventilation

movement of air in and out of the lungs as we inhale and exhale

Alveolar-capillary gas exchange

involves the diffusion of oxygen and carbon dioxide between the alveoli and the pulmonary capillaries

mouth nose pharynx larynx

What composes the upper respiratory system?

trachea and lungs bronchi bronchioles alveoli pulmonary capillary network pleural membranes

What composes the lower respiratory system?

pharynx

a shared pathway for air and food

larynx

a cartilaginous structure that can be identified externally as the Adam’s apple

larynx

important for maintaining airway patency and protecting the lower airways from swallowed food and fluids

respiratory membrane

The alveolar and capillary walls form the _______

intrapleural pressure

pressure in the pleural cavity surrounding the lungs

intrapleural pressure

always slightly negative in relation to atmospheric pressure.

intrapulmonary pressure

pressure within the lungs

intrapulmonary pressure

always equalizes with atmospheric pressure.

tidal volume

500 mL of air is inspired and expired with each breath. This is known as

anterior neck muscles intercostal muscles muscles of the abdomen

Accessory muscles of respiration

Lung compliance

the expansibility or stretchability of lung tissue, which plays a significant role in the ease of ventilation

atelectasis

collapse of a portion of the lung.

lung recoil

the continual tendency of the lungs to collapse away from the chest wall

Surfactant

a lipoprotein produced by specialized alveolar cells, acts like a detergent, reducing the surface tension of alveolar fluid

Diffusion

the movement of gases or other particles from an area of greater pressure or concentration to an area of lower pressure or concentration.

partial pressure

the pressure exerted by each individual gas in a mixture according to its concentration in the mixture

PO2

100 mmHg in alveoli and 60 mmHg in venous blood of pulmonary arteries

PCO2

45 mmHg in venous blood entering the pulmonary capillaries and 40 mmHg in alveoli

hemoglobin; oxyhemoglobin

97% of oxygen combines loosely with ______ as _______

hematocrit

the percentage of the blood that is erythrocytes

respiratory center

a number of groups of neurons located in the medulla oblongata and pons of the brain

medulla oblongata

a chemosensitive center in the ___________ is highly responsive to increases in blood CO2 or hydrogen ion concentration

carotid bodies; aortic bodies

special neural receptors sensitive to decreases in O2 concentration are located outside the central nervous system in the ________ and __________ located above and below the aortic arch

2 weeks of age

When do the lungs reach full inflation in neonates?

FALSE; lower PO2

TRUE or FALSE: The higher the altitude, the higher the PO2 an individual breathes

• Patency (open airway) • The movement of air into or out of the lungs • The diffusion of oxygen and carbon dioxide between the alveoli and the pulmonary capillaries • The transport of oxygen and carbon dioxide via the blood to and from the tissue cells.

Respiratory function can be altered by conditions that affect:

eupnea

Normal respiration; quiet, rhythmic, and effortless

Tachypnea

rapid respirations; seen with fevers, metabolic acidosis, pain, and hypoxemia.

Bradypnea

abnormally slow respiratory rate, which may be seen in clients who have taken drugs such as morphine or sedatives, who have metabolic alkalosis, or who have increased intracranial pressure (e.g., from brain injuries)

Apnea

the absence of any breathing

Hypoventilation

inadequate alveolar ventilation; may be caused by either slow or shallow breathing, or both

hypercarbia or hypercapnia

increased levels of carbon dioxide

Hyperventilation

the increased movement of air into and out of the lungs

Kussmaul’s breathing

One particular type of hyperventilation that accompanies metabolic acidosis; body attempts to compensate for increased metabolic acids by blowing off acid in the form of CO2

Cheyne-Stokes respirations

marked rhythmic waxing and waning of respirations from very deep to very shallow with short periods of apnea commonly caused by chronic diseases, increased intracranial pressure, or drug overdose

Biot’s (cluster) respirations

shallow breaths interrupted by apnea; may be seen in clients with CNS disorders

Orthopnea

inability to breathe easily unless sitting upright or standing

dyspnea.

Difficulty breathing or the feeling of being short of breath (SOB)

Hypoxemia

reduced oxygen levels in the blood

Rapid pulse Rapid, shallow respirations and dyspnea Increased restlessness or light-headedness Flaring of the nares Substernal or intercostal retractions Cyanosis

Clinical Manifestations of Hypoxia

1. The blood must contain about 5 g or more of unoxygenated hemoglobin per 100 mL of blood

2. the surface blood capillaries must be dilated

Cyanosis requires two conditions, what are those?

TRUE (Note: why???)

TRUE or FALSE: Severe anemia or the administration of epinephrine will eliminate cyanosis as a sign even if the client is experiencing hypoxia

3 to 5 minutes

The cerebral cortex can tolerate hypoxia for only _________ before permanent damage occurs.

Acute

Acute or Chronic Hypoxia? - Person usually appears anxious, tired, and drawn

Chronic

Acute or Chronic Hypoxia? - client often appears fatigued and is lethargic; fingers and toes may be clubbed

sputum specimens throat cultures visualization procedures venous and arterial blood specimens pulmonary function tests

Diagnostic tests to assess respiratory status, function, and oxygenation.

Tidal volume (VT)

Volume inhaled and exhaled during normal quiet breathing

Inspiratory reserve volume (IRV)

Maximum amount of air that can be inhaled over and above a normal breath

Expiratory reserve volume (ERV)

Maximum amount of air that can be exhaled following a normal exhalation

Residual volume (RV)

The amount of air remaining in the lungs after maximal exhalation

Total lung capacity (TLC)

The total volume of the lungs at maximum inflation; calculated by adding the VT, IRV, ERV, and RV

Vital capacity (VC)

Total amount of air that can be exhaled after a maximal inspiration; calculated by adding the VT, IRV, and ERV

Inspiratory capacity

Total amount of air that can be inhaled following normal quiet exhalation; calculated by adding the VT and IRV

Functional residual capacity (FRC)

The volume left in the lungs after normal exhalation; calculated by adding the ERV and RV

Minute volume (MV)

The total volume or amount of air breathed in 1 minute

Ineffective Airway Clearance

NANDA Diagnosis; inability to clear secretions or obstructions from the respiratory tract to maintain a clear airway

Ineffective Breathing Pattern

NANDA Diagnosis; inspiration and/or expiration that does not provide adequate ventilation.

Impaired Gas Exchange

NANDA Diagnosis; excess or deficit in oxygenation and/or carbon dioxide elimination at the alveolar-capillary membrane.

Activity Intolerance

NANDA Diagnosis; insufficient physiological or psychological energy to endure or complete required or desired daily activities

alveolar collapse

Shallow respirations may potentiate _______________, which may cause decreased diffusion of gases and subsequent hypoxemia.

pooling of respiratory secretions

The result of inadequate chest expansion is ________________________, which ultimately harbor microorganisms and promote infection.

semi-Fowler’s or high-Fowler’s

The ___________ or ___________ position allows maximum chest expansion in clients who are confined to bed, particularly those with dyspnea

“good lung down"

Clients with severe pneumonia or other pulmonary disease in one lung, if positioned laterally, should be generally positioned with the ______________ down

dyspneic

____________________ clients often sit in bed and lean over their overbed tables (which are raised to a suitable height), usually with a pillow for support.

FALSE; Not harmful

TRUE or FALSE: Swallowing secretions are harmful

expectorate (spit out)

When coughing raises secretions high enough, the client may either _______________ or swallow them

deep-breathing exercises; coughing

The nurse can facilitate respiratory functioning by encouraging ____________ and ____________ to remove secretions from the airways.

huff

The ____ cough helps prevent the high expiratory pressures that collapse diseased airways

hydration

Adequate ______________ maintains the moisture of the respiratory mucous membranes

humidifiers

devices that add water vapor to inspired air.

nebulizers

used to deliver humidity and medications; they may be used with oxygen delivery systems to provide moistened air directly to the client.

bronchodilators

reduce bronchospasm; enhance the sympathetic nervous system

anti-inflammatory drugs

They work by decreasing the edema and inflammation in the airways and allowing a better air exchange e.g. glucocorticoids

leukotriene modifiers

These medications suppress the effects of leukotrienes on the smooth muscle of the respiratory tract.

drugs that help “break up” mucus, making it more liquid and easier to expectorate.

Guaifenesin

a common expectorant found in many prescription and nonprescription cough syrups.

codeine

When frequent or prolonged coughing interrupts sleep, a cough suppressant such as ________ may be prescribed.

digitalis glycosides

medication that act directly on the heart to improve the strength of contraction and slow the heart rate.

Beta-adrenergic stimulating agents

medication that increase cardiac output, thus improving O2 transport; dobutamine

Beta-adrenergic blocking agents

medication that affects the sympathetic nervous system to reduce the workload of the heart; popranolol

incentive spirometer

also referred to as sustained maximal inspiration devices (SMIs), measure the flow of air inhaled through the mouthpiece

flow-oriented volume-oriented

Two types of spirometers:

flow-oriented spirometer

spirometer that consists of one or more clear plastic chambers containing freely movable colored balls or disks.

volume-oriented spirometer

spirometer wherein When the client inhales, a piston-like plate or accordion-pleated cylinder rises as the client inspires, and markings on the side indicate the volume of inspiration achieved by the client.

vibration

series of vigorous quiverings produced by hands that are placed flat against the client’s chest wall.

Postural drainage

the drainage by gravity of secretions from various lung segments; two to three times daily depending on the degree of lung congestion

mucus clearance device (MCD)

used for clients with excessive secretions such as cystic fibrosis, COPD, and bronchiectasis

flutter mucus clearance device

an example of a mucus clearance device; small, handheld device with a hard plastic mouthpiece at one end and a perforated cover at the other end

hypoxemia

Supplemental oxygen is indicated for clients who have _____________ due to the reduced ability for diffusion of oxygen through the respiratory membrane, hyperventilation, or substantial loss of lung tissue due to tumors or surgery

severe anemia or blood loss

Others who may require oxygen are those with _________________, or similar conditions in which there are inadequate numbers of RBCs or hemoglobin to carry the oxygen.

over 4 L/min

liter flows that require humidifier

very low liter flows about 1 to 2 L/min

liter flows that do not require humidifier