“Doppler Ultrasonography” plus 2 more nursing article(s): NursingCrib.com Updates

Doppler Ultrasonography
Serum Creatinine
Electrocardiography (ECG)

Posted: 07 Sep 2010 07:55 PM PDT

Doppler ultrasonography evaluates blood flow in the major blood vessels of the arms and legs and in the extracranial cerebrovascular system. A handheld transducer directs high- frequency sound waves to the artery or vein being tested. The sound wave strike moving red blood cells and are reflected back to the transducer at frequencies that corresponds to blood flow velocity through the vessel. The transducer then amplifies the sound waves to permit direct listening and graphic recording of blood flow. Measurement of systolic pressure helps detect the presence, location, and extent of peripheral arterial occlusive disease.

Pulse volume recorder testing may be performed along with Doppler ultrasonography to yield a quantitative recording of changes in blood volume or flow in extremity or organ.

Purpose of Doppler Ultrasonography

To help diagnose venous insufficiency and superficial and deep vein thrombosis (popliteal, femoral, and iliac).
To help diagnose peripheral artery disease and arterial occlusion.
To monitor the patient who has had arterial reconstruction and bypass grafts.
To detect abnormalities of carotid artery blood flow associated with such conditions as aortic stenosis.
To evaluate possible arterial trauma.

Doppler Ultrasonography Procedure

Patient Preparation

Explain to the patient that Doppler ultrasonography is used to evaluate blood flow in the arms and legs or neck. Tell him who will perform the test and when.
Reassure the patient that the test doesn't involve risk or discomfort.
Inform the patient that he'll be asked to move his arms to different positions and to perform breathing exercises as measurements are taken.
Advise him that a small ultrasonic probe resembling a microphone is placed at various sites along veins or arteries, and blood pressure is checked at several sites.
Check with the vascular laboratory about special equipment or instructions.

Implementation

Doppler ultrasonography is performed bilaterally.
The patient is assisted into the supine position on the examination table with his arms at his sides.

Peripheral arterial evaluation

For peripheral arterial evaluation in the leg, the usual test sites are the common and superficial femoral, popliteal, posterior tibial, and dorsalis pedis arteries.
For peripheral arterial evaluation in the arm, the usual test sites are the subclavian, brachial, radial, and ulnar arteries.
Brachial blood pressure is measured, and the transducer is placed at various points along the test arteries.
The signals are monitored, and the waveforms are recorded for later analysis.
The blood flow velocity is monitored and recorded over the test artery.
Segmental limb blood pressures are obtained to localize arterial occlusive disease.

Peripheral venous evaluation

For peripheral venous evaluation in the leg, the usual test sites are the popliteal, superficial and common femoral veins, and posterior tibial vein.
For extracranial cerebrovascular evaluation, usual test sites are the supraorbital artery; the common, external, and internal carotid a arteries; the vertebral arteries; and the brachial, axillary, subclavian, and jugular veins.
The transducer is placed over the appropriate vessel, waveforms are recorded, and respiratory modulations are noted.
Proximal limb compression maneuvers are performed.
Augmentation after release of compression is noted to evaluate venous valve competency.
For test involving the legs and feet, the patient is asked to perform Valsalva's maneuver, and venous blood flow is recorded.

Nursing Interventions

Remove the conductive gel from the patient's skin.
Assist the patient to a comfortable position.

Interfering Factors

Unknown

Precautions

Bradyarrhythmias may occur if the probe is placed near the carotid sinus.
Make sure that the Doppler probe isn't placed over an open or draining lesion.

Serum Creatinine

Posted: 07 Sep 2010 07:43 PM PDT

A quantitative analysis of serum creatinine levels, the serum creatinine test provides a more sensitive measure of renal damage than do blood urea nitrogen levels because renal impairment is virtually the only cause of creatinine elevation.

Creatinine is a non-protein end product of creatinine metabolism that appears in serum in amount proportional to the body's muscle mass.

Purpose of Serum Creatinine Test

To assess glomerular filtration.
To screen for renal damage.

Serum Creatinine Test Procedure

Patient Preparation

Confirm the patient's identity using two patient identifiers according to facility policy.
Explain to the patient that the serum creatinine test is used to evaluate kidney function.
Tell the patient that the test requires a blood sample.
Explain to the patient that he may experience slight discomfort from the tourniquet and the needle puncture.
Instruct the patient that he doesn't need to restrict food and fluids.
Notify the laboratory and the practitioner of medications the patient is taking that may affect test results; they may need to be restricted.

Implementation

Perform a venipuncture and collect the sample in a 3 or 4 ml clot activator tube.
Handle the sample gently to prevent hemolysis.
Send the sample to the laboratory immediately.

Nursing Interventions

Send the sample to the laboratory immediately.
Apply direct pressure to the venipuncture site until bleeding stops.
Assess the venipuncture site for hematoma formation; if one develops, apply pressure.
Inform the patient that he may resume his usual medications that were discontinued before the test, as ordered.

Interpretation

Normal Results

In men, 0.8 to 1.2 mg/dl (SI, 62 to 115 pmol/L)
In women, 0.6 to 0.9 mg/dl (SI, 53 to 97 pmil/L)

Abnormal Results

Elevated levels generally indicate renal disease that has seriously damaged 50% or more of the nephrons.
Elevated levels may also indicate gigantism and acromegaly.

Interfering Factors

Ascorbic acid, barbiturates, and diuretics that may possibly increase.
Exceptionally large muscle mass, such as found in athletes that may possibly increase despite normal renal function.
Phenolsulfonphthalein given within the previous 24 hours (possible increase, if the test is based on Jaffe's reaction.

Complications

Hematoma to the puncture site.

Electrocardiography (ECG)

Posted: 07 Sep 2010 07:31 PM PDT

Electrocardiography is the most commonly used test for evaluating cardiac status, graphically records the electrical current (electrical potential) generated by the heart. This current radiates from the heart in all directions and, on reaching the skin, is measured by electrodes connected to an amplier and strip chart recorder. The standard resting ECG uses five electrodes to measure the electrical potential from 12 different leads; the standard limb leads (I,II,III), the augmented limb leads (aVf, aVL, and aVr), and the precordial, or chest, leads (V1 through V6).

ECG tracings normally consist of three identifiable waveforms: the P wave, the QRS complex, and the T wave. The P wave depicts atrial depolarization; the QRS complex, ventricular depolarization; and the T wave, ventricular repolarization.

Computerized ECG machines use small electrode tabs that peel off a sheet and adhere to the patient's skin. The entire ECG tracing is displayed on a screen so abnormalities can be corrected before printing; then it's printed on one sheet of paper. Electrode tabs can remain on the patient's chest, arms, and legs to provide continuous lead placement for serial ECG studies.

Purpose of Electrocardiography (ECG)

To help identify primary conduction abnormalities, cardiac arrhythmias, cardiac hypertrophy, pericarditis, electrolyte imbalances, myocardial ischemia, and the site and extent of myocardial infarction.
To monitor recovery from an MI.
To evaluate the effectiveness of cardiac medication.
To assess pacemaker performance
To determine effectiveness of thrombolytic therapy and the resolution of ST-segment depression or elevation and T-wave changes.

Electrocardiography (ECG) Procedure

Patient Preparation for Electrocardiography (ECG)

Explain to the patient the need to lie still, relax, and breathe normally during the procedure.
Note current cardiac drug therapy on the test request form as well as any other pertinent clinical information, such as chest pain or pacemaker.
Explain that the test is painless and takes 5 to 10 minutes.

Implementation

Place the patient in a supine or semi-Fowler's position.
Expose the chest, ankles, and wrists.
Place electrodes on the inner aspect of the wrists, on the medical aspect of the lower legs, and on the chest.
After all electrodes are in place, connect the lead wires.
Press the START button and input any required information.
Make sure that all leads are represented in the tracing. If not, determine which electrode has come loose, reattach it, and restart the tracing.
All recording and other nearby electrical equipment should be properly grounded.
Make sure that the electrodes are firmly attached.

Nursing Interventions

Disconnect the equipment, remove the electrodes, and remove the gel with a moist cloth towel.
If the patient is having recurrent chest pain or if serial ECG's are ordered, leave the electrode patches in place.

Interpretations

Normal Results

P wave that doesn't exceed 2.5 mm (0.25 mV) in height or last longer than 0.12 second.
PR interval (includes the P wave plus the PR segment) persisting for 0.12 to 0.2 second for heart rates above 60 beats/min.
QT interval that varies with the heart rate and lasts 0.4 to 0.52 second for heart rates above 60 beats/min.
Voltage of the R wave leads V1 through V6 that doesn't exceed 27 mm.
Total QRS complex lasting 0.06 to 0.1 second.

Abnormal Results

Myocardial infarction (MI), right or left ventricular hypertrophy, arrhythmias, right or left bundle-branch block, ischemia, conduction defects or pericarditis, and electrolyte abnormalities.
Abnormal wave forms during angina episodes or during exercise.

Precautions

The recording equipment and other nearby electrical equipment should be properly grounded to prevent electrical interference.
Double-check color codes and lead markings to be sure connectors march.
Make sure that the electrodes are firmly attached, and reattached them if loose skin contact is suspended. Don't use cables that are broken, frayed, or bare.

Interfering Factors