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Med-Surg 2 Exam 2 Questions and
Answers. Verified Solutions
Assessment of Respiratory Function Ch. 20
- The upper respiratory tract, known as the upper airway, warms and filters inspired
air so that the lower respiratory tract (the lungs) can accomplish gas exchange and
diffusion.
o Gas exchange involves delivering oxygen to the tissues through the bloodstream
and expelling waste gases, such as carbon dioxide, during expiration.
- The respiratory system depends on the cardiovascular system for perfusion
Upper Respiratory Tract
- Nose, Sinuses and nasal passages, Pharynx, Tonsils, adenoids, Larynx: epiglottis,
glottis, vocal cords, and cartilages,Trachea
Lower Respiratory Tract
- Two lungs: five lobes
o Left: upper and lower
o Right: upper, middle, and lower
- Pleura, Mediastinum, Bronchi and bronchioles, Alveoli- functional unit
Function of the Respiratory SystemOxygen transport
- Oxygen is supplied to, and carbon dioxide is removed from, cells by the way of
the circulating blood through the thin walls of the capillaries.
- Oxygen diffuses from the capillary through the capillary wall to the interstitial fluid.
- The movement of CO2 occurs by diffusion - from cell to blood.
- Used for cellular respiration
Respiration
- The oxygen concentration in blood within the capillaries of the lungs is lower than in the
lung’s alveoli.
o Because of this concentration gradient, oxygen diffuses from the alveoli to
the blood (from high concentration to low)
- Carbon dioxide has a higher concentration in the blood than in the alveoli.
o Diffuses from the blood into the alveoli (from high concentration to low)
o Gas exchange between the atmospheric air and blood and between blood and
cells of body
o Gas exchange takes place in the alveoli
Ventilation
- Requires movement of the walls of the thoracic cage and of its floor, the diaphragm.
- The effect of these movements is alternately to increase and decrease the capacity of
the chest.
- When the capacity of the chest is increased, air enters through the trachea (inspiration) &
moves into the bronchi, bronchioles, & alveoli, inflates the lungs.
o Contraction of the diaphragm (movement of chamber floor downward) and
contraction of external intercostal muscles increases space in thoracic chamber,
lowering intra-thoracic pressure (there’s more space within the thoracic cage
less pressure) (negative pressure); air enters the airways and inflates the lungs
- When the chest wall and diaphragm return to their previous positions (expiration),
the lungs recoil and force the air out through the bronchi and trachea.
o Relaxation of the diaphragm (movement of chamber floor upward) (there’s less
space within the thoracic cage more pressure) relaxation of external intercostal
, muscles, increasing intrathoracic pressure (positive pressure), air exits the
airways, deflation and elastic recoil of the lungs
- Inspiration occurs during the first 1/3 of the respiratory cycle; expiration occurs during
the latter 2/3. Expiratory phase is normally passive, requiring very little energy.
Air Pressure VariancesAir flows from a region of higher pressure to lower pressure.
Airway Resistance
- Resistance is determined by the radius, or size of the airway through which the air
is flowing, as well as by lung volumes and airflow velocity.
- Causes of increased airway resistance include:
o Contraction of bronchial smooth muscle (asthma)
o Thickening of bronchial mucosa (chronic bronchitis)
o Obstruction of the airway by mucus, a tumor, or a foreign body
o Loss of lung elasticity as in emphysema
Compliance
- Is the elasticity and expandability of the lungs and thoracic structures.
- Increased compliance occurs if the lungs have lost their elastic recoil and become
over-distended (in emphysema).
- Decreased compliance occurs if the lungs and thorax are “stiff.”
o Morbid obesity, Pneumothorax, Hemothorax, Pleural effusion, Pulmonary edema,
Atelectasis, Pulmonary fibrosis, and Acute respiratory distress syndrome
(ARDS).
Lung Volumes and Capacities
- Lung function reflects the mechanics of ventilation, viewed in terms of lung volumes
and lung capacities.
o Lung volumes include tidal volume, inspiratory reserve volume,
expiratory reserve volume, and residual volume.
o Lung capacity is evaluated in terms of vital capacity, inspiratory
capacity, functional residual capacity, and total lung capacity.
Pulmonary Diffusion and Perfusion
- Oxygen crosses the alveolar–capillary membrane into arterial blood by
diffusion, perfusion carries oxygenated blood to all body tissues
- O2 diffuses from areas of higher partial pressure to areas of lower partial pressure
- O2 is transported to the cells of the body by combining with Hemoglobin
- Carbon dioxide is the end-product of metabolic combustion
- CO2 crosses the alveolar–capillary membrane into venous blood by diffusion,
perfusion carries deoxygenated blood back to the lungs
- CO2 diffuses more easily than O2 across the alveolar–capillary membrane
Physical Assessment of the Respiratory System
- Past health, social and family history
- Risk factors
o Smoking
o Exposure to secondhand smoke
o Family history of lung disease
o Genetics (asthma, COPD, CF, Alpha-1antitrypsin deficiency)
o Exposure to allergens and environmental pollutants
o Occupational hazards
Pulmonary Function Tests
, - Used in patients with chronic respiratory disorders to aid diagnosis.
- Performed to assess respiratory function and to determine the extent of dysfunction,
response to therapy, and as screening tests in potentially hazardous industries, such
as coal mining and exposure to asbestos
- Tests include measurements of lung volumes, ventilatory function, and the mechanics
of breathing, diffusion, and gas exchange.
- PFT results are interpreted on the basis of the degree of deviation from normal,
taking into consideration the patient’s height, weight, age, gender, and ethnicity.
Arterial Blood Gas Studies (Interpretation)
- ABG studies aid in assessing the ability of the lungs to provide adequate oxygen
and remove carbon dioxide, which reflects ventilation, and the ability of the
kidneys to reabsorb or excrete bicarbonate ions to maintain normal body pH,
which reflects metabolic states.
o Measurement of arterial oxygenation and carbon dioxide levels.
o Used to assess the adequacy of alveolar ventilation and the ability of the lungs to
provide oxygen and remove carbon dioxide.
o Also assesses acid–base balance
- Levels are obtained through an arterial puncture at the radial, brachial, or femoral
artery or through an indwelling arterial catheter.
- Complications: pain, infection, and hemorrhage.
Arterial
- pH: 7.40 (7.35-7.45)
- PaO2: 80-100 mm Hg
- SaO2: >95%
- PaCO2: 35-45 mm Hg
- HCO3 (Bicarb): 22-26 mEq/L
Bronchoscopy
- Is the direct inspection and examination of the larynx, trachea, and bronchi through either
a flexible fiber-optic bronchoscope or a rigid bronchoscope.
ProcedureThe purposes of diagnostic bronchoscopy are:
o Visualize tissues and determine nature, location and extent of pathologic process
o Collect secretions for analysis and to obtain tissue sample for diagnosis
o Determine whether a tumor can be resected surgically
o Diagnose sources of hemoptysis
- Therapeutic bronchoscopy is used to:
o Remove foreign bodies or secretions from the tracheobronchial tree
o Control bleeding, Treat postoperative atelectasis
o Destroy and excise lesions
o Provide brachytherapy (endo-bronchial radiation therapy).
o Also been used to insert stents to relieve airway obstruction
- Fiber-optic bronchoscopy allows biopsy of previously inaccessible tumors and can
be performed at the bedside.
- The rigid bronchoscope is a hollow metal tube with a light at its end. Used mainly
for removing foreign substances, investigating the source of massive hemoptysis, or
performing endobronchial surgical procedures. It is performed in the OR.
, - Complications include: Reaction to the local anesthetic, infection,
aspiration, bronchospasm, hypoxemia, pneumothorax, bleeding, perforation
Nursing Interventions
- Informed consent is obtained from the patient.
- Food and fluids are withheld for 4 to 8 hours before the test to reduce the risk
of aspiration when the cough reflex is blocked by anesthesia.
- After the procedure, the patient is NPO until the cough reflex returns, because
the preoperative sedation and local anesthesia impair the protective laryngeal reflex
and swallowing.
o Once the patient demonstrates a cough reflex, the nurse may offer ice chips
and eventually fluids.
o Monitor the patient’s respiratory status and observe for hypoxia,
hypotension, tachycardia, dysrhythmias, hemoptysis, and dyspnea.
o A small amount of blood-tinged sputum and fever may be expected within
the first 24 hours.
o Instruct the patient to report any SOB or bleeding immediately.
Thoracentesis Pg. 488
- In some respiratory disorders, pleural fluid may accumulate.
- Thoracentesis (aspiration of fluid and air from the pleural space).
- Purposes include:
o Removal of fluid or air from pleural cavity
o Aspiration of pleural fluid for analysis
o Pleural biopsy
o Instillation of medication into pleural space
- Studies of pleural fluid include:
o Gram stain, Culture & Sensitivity, Amylase, triglycerides
o Acid-fast staining and culture, Glucose, Cancer markers
o Differential cell count, Cytology, pH
o Total protein, Lactic dehydrogenase
Nursing Interventions
- Chest x-ray or ultrasound has been ordered and completed and consent signed
- assess patient for allergies to latex, antiseptic, or local anesthetic; and review
coagulation status (prothrombin time/INR and platelet count).
- Inform the patient about the nature of the procedure as well as:
o The importance of remaining immobile
o Pressure sensations to be experienced
o That minimal discomfort is anticipated after the procedure.
- Obtain baseline VS, O2 Sat, pain level, and respiratory status.
- Position the patient comfortably with adequate supports. If possible, place the patient
upright in one of the following positions:
o Sitting on the edge of the bed with the feet supported and arms on a padded
over- the-bed table.
o Straddling a chair with arms and head resting on the back of the chair.
o Lying on the unaffected side with the head of the bed elevated 30 to 45 degrees
if unable to assume a sitting position.
