Understanding the Cardiovascular System
Cardiovascular diagnostic tests and examinations are conducted by order of the physician to help determine the nature of the specific disease condition. Many of these tests or examinations may be repeated at intervals to determine the patient's progress or response to prescribed treatment. While some are performed on the nursing unit, many others are conducted only in special laboratories and hospital clinics.
The nursing paraprofessional's role in assisting with diagnostic tests and collection of specimens will vary, depending upon the test, the specimen, the condition of the patient, and the local situation and policy. Although they may seldom perform any part of the test themselves, they should be acquainted with those commonly performed in order to give intelligent patient care and appropriate assistance to the doctor, nurse, or technician. Click on the icon below to read about the general nursing knowledge required when preforming a cardiovascular diagnostic procedure.
In general, nurses should know:
(1) How and why the procedure is done and what, if any, reaction is expected from it.
(2) What explanation and physical care the patient should have before, during, and after the procedure. The informed, prepared patient is more apt to cooperate and to tolerate any inconvenience or discomfort incidental to the test.
(3) What equipment, clean or sterile, must be provided when assisting with the procedure and how to care for used equipment following the procedure.
(4) The role of the assistant in relation to that of the doctor, nurse, or technician performing the test.
General Preparatory Measures for Procedures
CAUTION: Always verify with the nurse or doctor what information you may give to the patient.
Procedures vary from one hospital to another concerning nursing unit preparation of patients who are to be sent or escorted to clinics, laboratories, or operating rooms.
These various departments set their own standing operating procedure in accordance with local directives and issue instructions to the nursing units. These instructions and the doctor's orders for the particular patient must be carried out carefully to ensure the best results for the patient.
Some additional tips to help prepare a patient for a procedure are outlined below:
Prepare the Patient Mentally. Tell the patient briefly what to expect and explain his role in the preparation. Mental preparation of the patient gives him emotional security and gains his confidence and cooperation.
Prepare the Patient Physically. Have the patient clean, properly dressed, and protected from exposure or drafts. Make sure that any specific preparation ordered has been accomplished, such as medication, rest for a required period, or restriction on food or liquids.
Have the Right Patient in the Right Place at the Right Time. If he is an ambulatory patient, give him specific directions on how to reach the clinic or laboratory. Transport an otherwise ambulatory patient who has received a sedative or other pretreatment medication in a wheelchair or on a stretcher. The responsibility of nursing unit personnel accompanying the patient ends only after the patient is placed in the care of the personnel who are to perform the procedure.
General Preparatory Measures for Procedures
In addition to the general rules mentioned in the previous paragraph, you should:
Assist the physician as required. This may involve obtaining equipment, opening sterile trays, preparing a sterile field, pouring solutions, preparing the patient's skin, positioning the patient, draping the patient, and assisting the physician in the performance of the procedure.
Reassure the patient and make him as comfortable as possible. NOTE: For some patients and some procedures, two assistants will be needed one to support and observe the patient and one to assist the doctor.
If a specimen is taken, attach to the specimen container a prepared label identifying the patient by name and register number, ward, date, and test. Forward the specimen to the laboratory immediately with the proper laboratory request slip.
General Nursing Care following Diagnostic Procedures
When a diagnostic procedure has been completed, nurses should complete the following duties:
Return the patient to his bed by the means ordered.
Check the orders of the physician who performed the procedure. Observe and report any unusual reactions of the patient. If there are no orders pertaining to taking vital signs, accomplish this nursing measure according to standard nursing unit procedures.
Use appropriate measure to relieve discomfort or pain.
If the patient has been sedated or anesthetized, ensure bed rest until he has completely reacted. Tell him to stay in bed and to signal for any needs. Use side rails according to standard procedures. Ensure the call light is with in reach of the patient.
If the procedure involves the patient's diet, notify food service to serve, modify, or cancel his meal as appropriate.
Explain to the patient that he will be notified when he may resume his normal regime. When this time arrives, inform him promptly.
Fluoroscopy is used to look for abnormal configuration, tumors, and calcifications in the heart, aorta, and pulmonary vessels, to find congestion of the lungs, and to detect pleural or pericardial effusions.
Fluoroscopy shows the heart in action and is used more often than other x-ray methods in cardiologic examinations. During examination of the heart under fluoroscopy, barium is given by mouth so the outline of the esophagus can be seen.
An enlarged left atrium pushes the esophagus aside as it becomes larger. There is no preparation of the patient for this examination.
The aorta and its branches are studied by the injection of a contrast medium through a plastic catheter or with a needle directly into the aorta.
Terms used in connection with the aortogram are retrograde aortogram (retrograde meaning against the direction of blood flow) and translumbar aortogram (meaning the injection is made below the twelfth rib and to the left of the spine). No preparation of the patient is necessary.
This is a procedure in which an opaque medium is injected into a vein followed by a rapid series of x-ray pictures taken of the course of the medium through the heart, to the lungs, back to the heart, and out through the aorta.
The dosage of contrast media is calculated according to the kilograms of body weight. The solution is injected through a large bore (12 gauge) needle held in position in the vein, usually by a "cut down."
Speed of injection is imperative, since the solution must pass through the heart in a large bolus to make possible a good examination. The solution is injected after the patient has been instructed to inhale deeply. The inspiration is held for the entire series of x-rays.
This diagnostic method is recognized for precision in detecting congenital cardiac defects. Individual chambers of the heart are visualized, pathways for the blood stream are demonstrated, and chamber enlargement can be seen.
The opaque medium may cause a flushing sensation as it flows through the body. If necessary, the studies may be conducted under mild anesthesia. After one complete circulation, the opaque media is so diluted that it is no longer visible by x-ray.
No special preparation of the patient is necessary unless anesthesia is to be given. In that event, food may be withheld prior to the studies. A record of the patient's weight should be sent to the x-ray department with him.
This is a procedure in which a radiopaque catheter is manipulated through the heart under fluoroscopic observation. The exterior end of the catheter is connected by a three-way stopcock to a saline filled regulated drip system that also contains a pressure gauge (strain gauge) and a camera.
During the procedure the blood pressures within the heart are automatically transmitted to the strain gauge that, in turn, transmits the pressure to the camera recording the findings on photographic film.
Samples of blood are also withdrawn from the heart chambers and great vessels. The samples are analyzed for oxygen content.
The electrocardiogram (ECG) is a graphic recording of the electrical impulses produced in association with the heartbeat. Impulse formation and conduction produce weak electrical currents that spread throughout the entire body.
By connecting certain points on the body to a recording instrument, these currents can be recorded as a graphic representation of the heartbeat, measured against time. Time is expressed on the special ECG graph paper by vertical and horizontal lines.
The ECG provides quite a bit of valuable information for the small amount of effort involved in obtaining an ECG recording. It is a procedure that is completely noninvasive and without risk to the patient. It is easily performed by anyone with the proper training. The ECG provides information about the heart rate, rhythm, the condition of the myocardium, the presence of ischemia or necrosis, conduction abnormalities, the presence of certain drugs, and the effects of disturbed electrolytes.
Stress testing or exercise testing is done to assess cardiac function. Stress testing is accomplished by having the patient climb stairs, pedal a stationary bicycle, or walk a treadmill. The exercise is gradually increased (climb or walk faster, pedal harder) while the patient is monitored.
Electrocardiogram electrodes attached to the patient record tracings before, during, and after exercise. Additionally, blood pressure, physical appearance, and chest pain levels are monitored closely.
Blood pressure is defined as the pressure exerted by the blood on the walls of the blood vessels. When speaking of blood pressure, it is the arterial blood pressure that we are concerned with. When taking a patient's blood pressure with a sphygmomanometer and stethoscope, it is the arterial blood pressure that is being measured.
Blood pressure is registered by two numbers that represent the pressures exerted during contraction and relaxation of the heart.
Systolic pressure is the maximum pressure occurring during systole, or contraction, of the ventricles. It is the higher of the two numbers. Normal systolic pressure for the average resting adult is between 100-150 mmHg.
Diastolic pressure is the pressure occurring during diastole, the period of relaxation and filling of the ventricles. This is the lowest pressure. Normal diastolic pressure for the average resting adult is between 60-90 mmHg.
Blood pressure is best measured over a large artery. The most commonly used is the brachial artery. The cuff is wrapped around the upper arm and auscultation is done over the brachial artery in the antecubital space.
In patients with hypertension or other cardiovascular disease, it is best to measure blood pressure in both the right and left arms. There should be no more than 5 mmHg difference between the two readings. A greater difference is indicative of vascular disease.
The physician may order blood pressure checks to be done with the patient lying down, sitting, and standing. The corresponding rise or fall in pressure with the change of position may give the physician valuable information about the nature of the cardiovascular disease.
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