UNIT FOUR
562
Clinical Skills and Care
the artery causes the plunger of the syringe to rise as blood enters the syringe. After the needle is withdrawn from the artery, the health-care professional inserts it into a cork to prevent additional air from entering the syringe or uses a special needle that will not allow air to enter the syringe after the blood is drawn. The syringe is then transported to the laboratory in a bag or cup containing icy water, called a slurry, to keep it cold if it will not be tested within 20 minutes. ABGs measure the pH, the partial pressures of oxygen (PaO 2 ) and carbon dioxide (PaCO 2 ), the bicarbonate level (HCO 3 – ), and the oxygen saturation (SaO 2 ) of arterial blood. Information from ABGs will help you know your patient’s pH status. If the pH is above 7.45, the patient is in alkalosis. If the pH is below 7.35, the patient is in acidosis. Both of these conditions require immediate action by the health- care provider to correct. Blood gases also show if the cause of the acidosis or alkalosis is a respiratory problem, which would cause the PaCO 2 to be increased or decreased, or a metabolic problem as a result of kidney regulation of bicarbonate. In that case, the patient’s HCO 3 – levels would be above or below normal. Normal ranges for ABGs, along with the
significance of findings above and below normal, can be found in Table 28.2. ABGs usually are drawn by respiratory therapists or specially trained nurses or laboratory technicians. Registered nurses also may take a sample of arterial blood for ABGs from an arterial line in a critical care setting.
Nursing Interventions for Patients With Impaired Oxygenation
You will use a variety of nursing interventions to help pre- vent decreased oxygenation in your patients who have undergone surgery or who must remain in bed. In addition, there are a number of actions for you to take to improve oxy- genation in your patients with lung disorders. Turn, Cough, and Deep Breathe Patients who have undergone surgery or are on bedrest must be turned every 2 hours to prevent respiratory complications caused by immobility. (See Chapter 16 for a review of com- plications of immobility.) In addition to assisting patients to turn from side to side, you must encourage patients to take three deep breaths and then cough to remove secre- tions from the lungs and airways. Safety: You need to assist
Table 28.1 Respiratory Diagnostic Tests and Their Purposes
Diagnostic Test
Purpose
Signi fi cance of Abnormal Results
Pulmonary function tests
To determine lung capacity, volume, and fl ow rates. Measures the amount of air that can be exhaled with force using a peak fl owmeter. Used to visualize lung fi elds; air appears dark so it can be determined whether all lobes are fi lling with air. Fluid, dense tissue, and in fi ltrate appear white. To determine reaction to the presence of tuberculin bacillus in skin layers.
Used to diagnose obstructive or restrictive lung diseases such as COPD and asthma. Used to determine dosage and frequency of some respi- ratory medications. Can be used by patient to monitor the effectiveness of medications. Used to determine lung fi lling and size of cardiac silhou- ette and to identify tumors, pneumonia, in fi ltrate, and effusions. If skin over and around injection site elevates and indu- rates (gets hard) with or without redness, the result is positive. This indicates past exposure to the disease or current disease. Must be followed up with chest x-ray for con fi rmation. False positives are caused by the malaria vaccine given in many African countries. Used to diagnose lung conditions such as interstitial dis- ease, infection, airway blockage, and cancer; also used to dilate narrowed airways.
Peak fl ow
Chest x-ray
Tuberculin skin test
Bronchoscopy
To visualize trachea and bronchi; to obtain biopsies of abnormal tissue; and to obtain samples of lung cells, fl uids, and other material inside the air sacs.
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