Definition
Cardiac marker tests identify blood analytes associated with myocardial infarction (MI), commonly known as a heart attack.
Purpose
Cardiac markers help physicians to assess acute coronary syndromes and to identify and manage high-risk patients. Creatine kinase-MB (CK-MB), myoglobin, homocysteine, C-reactive protein (CRP), troponin T (cTnT), and troponin I (cTnI) are all used for assessment of the suspected acute myocardial infarction. CK-MB, cTnT, and cTnI may also be used to identify and manage high-risk patients.
Precautions
C-reactive protein results may be affected by the use of oral contraceptives, NSAIDs, steroids, salicyltes, intrauterine devices (IUDs), and overnight sample refrigeration. Homocysteine levels may be affected by smoking, diabetes, and coffee.
Description
Creatine kinase (CK)
Creatine kinase is an enzyme responsible for transferring a phosphate group from ATP to creatine. It is composed of M and/or B subunits that form CK-MM, CKMB, and CK-BB isoenzymes. Total CK (the activity of the MM, MB, and BB isoenzymes) is not myocardial-specific. However, the MB isoenzyme (also called CK-2) comprises about 40% of the CK activity in cardiac muscle and 2% or less of the activity in most muscle groups and other tissues. In the proper clinical setting, MB is both a sensitive and specific marker for myocardial infarction. MB usually becomes abnormal three to four hours after an MI, peaks in 10 to 24 hours, and returns to normal within 72 hours. However, an elevated serum MB may occur in people with severe skeletal muscle damage (such as in muscular dystrophy or a crush injury) and renal failure. In such cases, the CK index (MB divided by total CK) is very helpful. If the index is under 4%, a nonmyocardial cause of a high MB should be suspected. C-MB is considered the benchmark for cardiac markers of myocardial injury. Measurement of CK-MB may be performed via electrophoresis or immunoassays; the latter demonstrates better analytical sensitivity and better precision.
CK-MB isoforms can be used to determine whether thrombolytic therapy (such as treatment with tissue plasminogen activator to dissolve a blood clot in the coronary artery) has succeeded. MB isoforms are different molecular forms of MB found in the circulation. When MB is released into the blood, the terminal lysine of the M sub-unit is removed by an enzyme in the plasma. This results in a molecule with faster electrophoretic mobility, called CK-21. This is the prevalent form of MB in the blood. The slower form, designated CK-22, is the unmodified cardiac form of MB. After successful thrombolytic therapy, the unmodified form of MB is rapidly flushed into the blood, causing it to become the dominant isoform.
Myoblobin
Myoglobin is a protein found in both skeletal and myocardial muscle. It is released rapidly after tissue injury and may be elevated as early as one hour after myocardial injury, though it may also be elevated due to skeletal muscle trauma. However, if myoglobin values do not rise within three to four hours after a person shows acute symptoms, it is highly unlikely that he or she had an MI. There are several measurement methods available, including fluorometric, nephelometric, and turbid-metric assays; plus immunochromatography-based tests designed for qualitative, point-of-care testing.
Troponin T and troponin I
Troponin C, I, and T are proteins that form the thin filaments of muscle fibers and regulate the movement of contractile proteins in muscle tissue. Skeletal and cardiac forms are structurally distinct, and antibodies can be produced that react only with the cardiac forms of troponin I and troponin T.
Cardiac troponin T (cTnT) and cardiac troponin I (cTnI) are the newest additions to the list of cardiac markers. Troponins are specific to heart muscle. They have enabled the development of assays that can detect heart muscle injury with great sensitivity and specificity. While these markers have been used mainly to aid in the diagnosis of chest-pain patients with nondiagnostic electrocardiograms, they are also used as prognostic indicators of a MI. According to the American Heart Association, "Several studies have identified a measurable relationship between cardiac troponin levels and long-term outcome after an episode of chest discomfort. They suggest that these tests may be particularly useful to evaluate levels of risk. In other words, it's possible that the results of a troponin test could be used to identify people at either low risk or high risk for later, serious heart problems."
Several commercially available quantitative immunoassays are available for for the measurement of cTnI and cTnT. There is also a qualitative cTnI test, targeted at bedside testing.
C-reactive protein (CRP)
CRP is a protein found in serum or plasma at elevated levels during a inflammatory processes. The protein can be measured via a variety of methods, including EIA or ELISA, for the quantitative or semiquantitative determination of C-reactive protein in human serum, particle agglutination tests that provide semiquantitative results, and laser and rate nephelometery tests that measure antigen-antibody complexes by light dispersion.
CRP binds to the C polysaccharide of the capsule of Streptococcus pneumoniae. It is a sensitive marker of acute and chronic inflammation and infection, and in such cases is increased several hundred-fold. Several recent studies have demonstrated that CRP levels are useful in predicting the risk for a thrombotic event. These studies suggest that a high-sensitivity assay for CRP be used that is capable of measuring the very low level normally found in serum (0.1 to 2.5 mg/L). Heart patients who have persistent CRP levels between 4 and 10 mg/L, with clinical evidence of low-grade inflammation, should be considered to be at increased risk for thrombosis. People can be stratified into four groups of increased risk based upon the quartile in which their CRP levels fall.
Homocysteine
Homocysteine is an amino acid. According to the American Heart Association, studies have shown that too much homocysteine in the blood is related to a higher risk of coronary heart disease, stroke, and peripheral vascular disease; and that it may also have an effect on atherosclerosis. High levels of homocysteine are the result of inheritance or dietary excess and have been implicated in vascular-wall injury. One immunoassay is available for it. It is believed that laboratory testing for plasma homocysteine levels can improve the assessment of risk, particularly in patients with a personal or family history of cardiovascular disease, but in whom the well-established risk factors (smoking, high blood cholesterol, high blood pressure, physical inactivity, obesity, and diabetes) do not exist. Homocysteine levels are obtained via high-performance chromatography with electrochemical detection.
Preparation
These assays require a sample of blood, which is typically obtained via a standard venipuncture procedure. Homocysteine tests require the patient to fast. Homocysteine is stable only in separated refrigerated or frozen plasma for 48 hours.
Aftercare
Discomfort or bruising may occur at the puncture site, or the person may feel dizzy or faint. Applying pressure to the puncture site until the bleeding stops reduces bruising. Warm packs to the puncture site relieve discomfort.
Complications
There are no complications associated with these tests.
Results
Normal results vary, based on the laboratory and method used. Unless otherwise specified, the following information is from the American College of Cardiology and the American Heart Association.
* Total CK: Reference value is 38 to 174 units/L for men and 96 to 140 units/L for women. The values begin to rise within four to six hours and peak at 24 hours. Values return to normal within three to four days.
* CK-MB: Reference value is 10 to 13 units/L. The values begin to rise within three to four hours and peak at 10 to 24 hours. Values return to normal within two to four days.
* Troponin T: Reference value is less than 0.1 ng/mL. The values begin to rise within two to four hours and peak at 10 to 24 hours. Values return to normal within five to 14 days.
* Troponin I: Reference value is less than 1.5 ng/mL. The values begin to rise within two to four hours and peak at 10 to 24 hours. Values return to normal within five to 10 days.
* CK-MB isoforms: Reference value is a ratio of 1.5 or greater. The values begin to rise within two to four hours and peak at six to 12 hours. Values return to normal within 12 to 24 hours.
* Myoglobin: Reference value is less than 110 ng/mL. The values begin to rise within one to two hours and peak at four to eight hours. Values return to normal within 12 to 24 hours.
* Homocysteine: The normal fasting level for plasma is five to 15 micromol/L. Moderate, intermediate, and severe hyperhomocysteinemia refer to concentrations between 16 and 30, between 31 and 100, and less than 100 micromol/L, respectively.
* C-reactive protein: According to the U.S. Food and Drug Administration, in healthy people, reference values are below 5 mg/dL; in various diseases, this threshold is often exceeded within four to eight hours after an acute inflammatory event, with CRP values reaching approximately 20 to 500 mg/dL.
Health care team roles
Cardiac marker tests are usually performed by clinical laboratory scientists, medical technologists, or clinical laboratory technicians.//enotes.com
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Showing posts with label DIAGNOSTIC PROCEDURES. Show all posts
Showing posts with label DIAGNOSTIC PROCEDURES. Show all posts
Saturday, February 27, 2010
Friday, December 18, 2009
Abdominal Ultrasound
enotes.com
Definition
Abdominal ultrasound uses high frequency sound waves to produce two-dimensional images of the body's soft tissues, which are used for a variety of clinical applications, including diagnosis and guidance of treatment procedures. Ultrasound does not use ionizing radiation to produce images, and in comparison to other diagnostic imaging modalities, it is low cost, safe, fast, and versatile.
Purpose
Abdominal ultrasound is used in the hospital radiology department and emergency department, as well as in physician offices for a number of clinical applications. Ultrasound has a great advantage over x-ray imaging technologies in that it does not damage tissues with ionizing radiation. Ultrasound is also generally far better than plain x-rays at distinguishing the subtle variations of soft tissue structures, and can be used in any of several modes, depending on the area of interest.
As an imaging tool, abdominal ultrasound generally is indicated for patients afflicted with chronic or acute abdominal pain; abdominal trauma; an obvious or suspected abdominal mass; symptoms of liver disease, pancreatic disease, gallstones, spleen disease, kidney disease and urinary blockage; or symptoms of an abdominal aortic aneurysm.
Specifically:
* Abdominal pain. Whether acute or chronic, pain can signal a serious problem—from organ malfunction or injury to the presence of malignant growths. Ultrasound scanning can help doctors quickly sort through potential causes when presented with general or ambiguous symptoms. All of the major abdominal organs can be studied for signs of disease that appear as changes in size, shape, and internal structure.
* Abdominal trauma. After a serious accident, such as a car crash or a fall, internal bleeding from injured abdominal organs is often the most serious threat to survival. Neither the injuries nor the bleeding may be immediately apparent. Ultrasound is very useful as an initial scan when abdominal trauma is suspected, and it can be used to pinpoint the location, cause, and severity of hemorrhaging. In the case of puncture wounds, from a bullet for example, ultrasound can locate the foreign object and provide a preliminary survey of the damage. (CT scans are sometimes used in trauma settings.)
* Abdominal mass. Abnormal growths—tumors, cysts, abscesses, scar tissue, and accessory organs—can be located and tentatively identified with ultrasound. In particular, potentially malignant solid tumors can be distinguished from benign fluid-filled cysts. Masses and malformations in any organ or part of the abdomen can be found.
* Liver disease. The types and underlying causes of liver disease are numerous, though jaundice tends to be a general symptom. Ultrasound can differentiate between many of the types and causes of liver malfunction, and is particularly good at identifying obstruction of the bile ducts and cirrhosis, which is characterized by abnormal fibrous growths and reduced blood flow.
* Pancreatic disease. Inflammation and malformation of the pancreas are readily identified by ultrasound, as are pancreatic stones (calculi), which can disrupt proper functioning.
* Gallstones. Gallstones are an extremely common cause of hospital admissions. These calculi can cause painful inflammation of the gallbladder and also obstruct the bile ducts that carry digestive enzymes from the gall-bladder bladder and liver to the intestines. Gallstones are readily identifiable with ultrasound.
* Spleen disease. The spleen is particularly prone to injury during abdominal trauma. It may also become painfully inflamed when infected or cancerous.
* Kidney disease. The kidneys are also prone to traumatic injury and are the organs most likely to form calculi, which can block the flow of urine and cause further systemic problems. A variety of diseases causing distinct changes in kidney morphology can also lead to complete kidney failure. Ultrasound imaging has proven extremely useful in diagnosing kidney disorders, including blockage or obstruction.
* Abdominal aortic aneurysm. This is a bulging weak spot in the abdominal aorta, which supplies blood directly from the heart to the entire lower body. A ruptured aortic aneurysm is imminently life-threatening. However, it can be readily identified and monitored with ultrasound before acute complications result.
* Appendicitis. Ultrasound is useful in diagnosing appendicitis, which causes abdominal pain.
Ultrasound technology can also be used for treatment purposes, most frequently as a visual aid during surgical procedures—such as guiding needle placement to drain fluid from a cyst, or to guide biopsies.
Precautions
Ultrasound waves of appropriate frequency and intensity are not known to cause or aggravate any medical condition.
The value of ultrasound imaging as a medical tool, however, depends greatly on the quality of the equipment used and the skill of the medical personnel operating it. More accurate results are obtained when ultrasound is performed by a clinician skilled in sonography. Basic ultrasound equipment is relatively inexpensive to obtain, and any physician with the equipment can perform the procedure whether specifically trained in ultrasound scanning and interpretation or not. Patients should not hesitate to verify the credentials of technologists and physicians performing ultrasound scanning, as well as the quality of the equipment used and the benefits of the proposed procedure.
In cases where ultrasound is used as a treatment tool, patients should educate themselves about the proposed procedure with the help of their doctors—as is appropriate before any surgical procedure. Also, any abdominal ultrasound procedure, diagnostic or therapeutic, may be hampered by a patient's body type or other factors, such as the presence of excessive bowel gas (which is opaque to ultrasound). In particular, very obese people are often not good candidates for abdominal ultrasound.
Description
Ultrasound includes all sound waves above the frequency of human hearing—about 20 thousand hertz, or cycles per second. Medical ultrasound generally uses frequencies between one and 10 megahertz (1-10 MHz). Higher frequency ultrasound waves produce more detailed images, but are also more readily absorbed and so cannot penetrate as deeply into the body. Abdominal ultrasound imaging is generally performed at frequencies between 2-5 MHz.
An ultrasound scanner consists of two parts: the transducer and the data processing unit. The transducer both produces the sound waves that penetrate the body and receives the reflected echoes. Transducers are built around piezoelectric ceramic chips. (Piezoelectric refers to electricity that is produced when you put pressure on certain crystals such as quartz.) These ceramic chips react to electric pulses by producing sound waves (they are transmitting waves) and react to sound waves by producing electric pulses (receiving). Bursts of high-frequency electric pulses supplied to the transducer cause it to produce the scanning sound waves. The transducer then receives the returning echoes, translates them back into electric pulses, and sends them to the data processing unit—a computer that organizes the data into an image on a television screen.
Because sound waves travel through all the body's tissues at nearly the same speed—about 3,400 miles per hour—the microseconds it takes for each echo to be received can be plotted on the screen as a distance into the body. The relative strength of each echo, a function of the specific tissue or organ boundary that produced it, can be plotted as a point of varying brightness. In this way, the echoes are translated into an image.
Four different modes of ultrasound are used in medical imaging:
* A-mode. This is the simplest type of ultrasound in which a single transducer scans a line through the body with the echoes plotted on screen as a function of depth. This method is used to measure distances within the body and the size of internal organs.
* B-mode. In B-mode ultrasound, a linear array of transducers simultaneously scans a plane through the body that can be viewed as a two-dimensional image on screen.
* M-Mode. The M stands for motion. A rapid sequence of B-mode scans whose images follow each other in sequence on screen enables doctors to see and measure range of motion, as the organ boundaries that produce reflections move relative to the probe. M-mode ultrasound has been put to particular use in studying heart motion.
* Doppler mode. Doppler ultrasonography includes the capability of accurately measuring velocities of moving material, such as blood in arteries and veins. The principle is the same as that used in radar guns that measure the speed of a car on the highway. Doppler capability is most often combined with B-mode scanning to produce images of blood vessels from which blood flow can be directly measured. This technique is used extensively to investigate valve defects, arteriosclerosis, and hypertension, particularly in the heart, but also in the abdominal aorta and the portal vein of the liver.
The actual procedure for a patient undergoing an abdominal ultrasound is relatively simple, regardless of the type of scan or its purpose. Fasting for at least eight hours prior to the procedure ensures that the stomach is empty and as small as possible, and that the intestines and bowels are relatively inactive. This also helps the gallbladder become more visible. Prior to scanning, an acoustic gel is applied to the skin of the patient's abdomen to allow the ultrasound probe to glide easily across the skin and also to better transmit and receive ultrasonic pulses. The probe is moved around the abdomen's surface to obtain different views of the target areas. The patient will likely be asked to change positions from side to side and to hold the breath as necessary to obtain the desired views. Usually, a scan will take from 20 to 45 minutes, depending on the patient's condition and anatomical area being scanned.
Ultrasound scanners are available in different configurations, with different scanning features. Portable units, which weigh only a few pounds and can be carried by hand, are available for bedside use, office use, or use outside the hospital, such as at sporting events and in ambulances. Portable scanners range in cost from $10,000 to $50,000. Mobile ultrasound scanners, which can be pushed to the patient bedside and between hospital departments, are the most common comfiguration and range in cost from $100,000 to over $250,000, depending on the scanning features purchased.
Preparation
A patient undergoing abdominal ultrasound will be advised by the physician about what to expect and how to prepare. As mentioned above, preparations generally include fasting.
Aftercare
In general, no aftercare related to the abdominal ultrasound procedure itself is required. Discomfort during the procedure is minimal.
Complications
Properly performed, ultrasound imaging is virtually without risk or side effects. Some patients report feeling a slight tingling and/or warmth while being scanned, but most feel nothing at all.
Results
As a diagnostic imaging technique, a normal abdominal ultrasound is one that indicates the absence of the suspected condition that prompted the scan. For example, symptoms such as abdominal pain radiating to the back suggest the possibility of, among other things, an abdominal aortic aneurysm. An ultrasound scan that indicates the absence of an aneurysm would rule out this life-threatening condition and point to other, less serious causes.
Because abdominal ultrasound imaging is generally undertaken to confirm a suspected condition, the results of a scan often will confirm the diagnosis, be it kidney stones, cirrhosis of the liver, or an aortic aneurysm. At that point, appropriate medical treatment as prescribed by a patient's physician is in order.
Health care team roles
Ultrasound scanning should be performed by a registered and trained ultrasonographer, either a technologist and/or a physician (radiologist, obstetrician/gynecologist). Ultrasound scanning in the emergency department may be performed by an emergency medicine physician, who should have appropriate training and experience in ultrasonography.
Read More ..
Definition
Abdominal ultrasound uses high frequency sound waves to produce two-dimensional images of the body's soft tissues, which are used for a variety of clinical applications, including diagnosis and guidance of treatment procedures. Ultrasound does not use ionizing radiation to produce images, and in comparison to other diagnostic imaging modalities, it is low cost, safe, fast, and versatile.
Purpose
Abdominal ultrasound is used in the hospital radiology department and emergency department, as well as in physician offices for a number of clinical applications. Ultrasound has a great advantage over x-ray imaging technologies in that it does not damage tissues with ionizing radiation. Ultrasound is also generally far better than plain x-rays at distinguishing the subtle variations of soft tissue structures, and can be used in any of several modes, depending on the area of interest.
As an imaging tool, abdominal ultrasound generally is indicated for patients afflicted with chronic or acute abdominal pain; abdominal trauma; an obvious or suspected abdominal mass; symptoms of liver disease, pancreatic disease, gallstones, spleen disease, kidney disease and urinary blockage; or symptoms of an abdominal aortic aneurysm.
Specifically:
* Abdominal pain. Whether acute or chronic, pain can signal a serious problem—from organ malfunction or injury to the presence of malignant growths. Ultrasound scanning can help doctors quickly sort through potential causes when presented with general or ambiguous symptoms. All of the major abdominal organs can be studied for signs of disease that appear as changes in size, shape, and internal structure.
* Abdominal trauma. After a serious accident, such as a car crash or a fall, internal bleeding from injured abdominal organs is often the most serious threat to survival. Neither the injuries nor the bleeding may be immediately apparent. Ultrasound is very useful as an initial scan when abdominal trauma is suspected, and it can be used to pinpoint the location, cause, and severity of hemorrhaging. In the case of puncture wounds, from a bullet for example, ultrasound can locate the foreign object and provide a preliminary survey of the damage. (CT scans are sometimes used in trauma settings.)
* Abdominal mass. Abnormal growths—tumors, cysts, abscesses, scar tissue, and accessory organs—can be located and tentatively identified with ultrasound. In particular, potentially malignant solid tumors can be distinguished from benign fluid-filled cysts. Masses and malformations in any organ or part of the abdomen can be found.
* Liver disease. The types and underlying causes of liver disease are numerous, though jaundice tends to be a general symptom. Ultrasound can differentiate between many of the types and causes of liver malfunction, and is particularly good at identifying obstruction of the bile ducts and cirrhosis, which is characterized by abnormal fibrous growths and reduced blood flow.
* Pancreatic disease. Inflammation and malformation of the pancreas are readily identified by ultrasound, as are pancreatic stones (calculi), which can disrupt proper functioning.
* Gallstones. Gallstones are an extremely common cause of hospital admissions. These calculi can cause painful inflammation of the gallbladder and also obstruct the bile ducts that carry digestive enzymes from the gall-bladder bladder and liver to the intestines. Gallstones are readily identifiable with ultrasound.
* Spleen disease. The spleen is particularly prone to injury during abdominal trauma. It may also become painfully inflamed when infected or cancerous.
* Kidney disease. The kidneys are also prone to traumatic injury and are the organs most likely to form calculi, which can block the flow of urine and cause further systemic problems. A variety of diseases causing distinct changes in kidney morphology can also lead to complete kidney failure. Ultrasound imaging has proven extremely useful in diagnosing kidney disorders, including blockage or obstruction.
* Abdominal aortic aneurysm. This is a bulging weak spot in the abdominal aorta, which supplies blood directly from the heart to the entire lower body. A ruptured aortic aneurysm is imminently life-threatening. However, it can be readily identified and monitored with ultrasound before acute complications result.
* Appendicitis. Ultrasound is useful in diagnosing appendicitis, which causes abdominal pain.
Ultrasound technology can also be used for treatment purposes, most frequently as a visual aid during surgical procedures—such as guiding needle placement to drain fluid from a cyst, or to guide biopsies.
Precautions
Ultrasound waves of appropriate frequency and intensity are not known to cause or aggravate any medical condition.
The value of ultrasound imaging as a medical tool, however, depends greatly on the quality of the equipment used and the skill of the medical personnel operating it. More accurate results are obtained when ultrasound is performed by a clinician skilled in sonography. Basic ultrasound equipment is relatively inexpensive to obtain, and any physician with the equipment can perform the procedure whether specifically trained in ultrasound scanning and interpretation or not. Patients should not hesitate to verify the credentials of technologists and physicians performing ultrasound scanning, as well as the quality of the equipment used and the benefits of the proposed procedure.
In cases where ultrasound is used as a treatment tool, patients should educate themselves about the proposed procedure with the help of their doctors—as is appropriate before any surgical procedure. Also, any abdominal ultrasound procedure, diagnostic or therapeutic, may be hampered by a patient's body type or other factors, such as the presence of excessive bowel gas (which is opaque to ultrasound). In particular, very obese people are often not good candidates for abdominal ultrasound.
Description
Ultrasound includes all sound waves above the frequency of human hearing—about 20 thousand hertz, or cycles per second. Medical ultrasound generally uses frequencies between one and 10 megahertz (1-10 MHz). Higher frequency ultrasound waves produce more detailed images, but are also more readily absorbed and so cannot penetrate as deeply into the body. Abdominal ultrasound imaging is generally performed at frequencies between 2-5 MHz.
An ultrasound scanner consists of two parts: the transducer and the data processing unit. The transducer both produces the sound waves that penetrate the body and receives the reflected echoes. Transducers are built around piezoelectric ceramic chips. (Piezoelectric refers to electricity that is produced when you put pressure on certain crystals such as quartz.) These ceramic chips react to electric pulses by producing sound waves (they are transmitting waves) and react to sound waves by producing electric pulses (receiving). Bursts of high-frequency electric pulses supplied to the transducer cause it to produce the scanning sound waves. The transducer then receives the returning echoes, translates them back into electric pulses, and sends them to the data processing unit—a computer that organizes the data into an image on a television screen.
Because sound waves travel through all the body's tissues at nearly the same speed—about 3,400 miles per hour—the microseconds it takes for each echo to be received can be plotted on the screen as a distance into the body. The relative strength of each echo, a function of the specific tissue or organ boundary that produced it, can be plotted as a point of varying brightness. In this way, the echoes are translated into an image.
Four different modes of ultrasound are used in medical imaging:
* A-mode. This is the simplest type of ultrasound in which a single transducer scans a line through the body with the echoes plotted on screen as a function of depth. This method is used to measure distances within the body and the size of internal organs.
* B-mode. In B-mode ultrasound, a linear array of transducers simultaneously scans a plane through the body that can be viewed as a two-dimensional image on screen.
* M-Mode. The M stands for motion. A rapid sequence of B-mode scans whose images follow each other in sequence on screen enables doctors to see and measure range of motion, as the organ boundaries that produce reflections move relative to the probe. M-mode ultrasound has been put to particular use in studying heart motion.
* Doppler mode. Doppler ultrasonography includes the capability of accurately measuring velocities of moving material, such as blood in arteries and veins. The principle is the same as that used in radar guns that measure the speed of a car on the highway. Doppler capability is most often combined with B-mode scanning to produce images of blood vessels from which blood flow can be directly measured. This technique is used extensively to investigate valve defects, arteriosclerosis, and hypertension, particularly in the heart, but also in the abdominal aorta and the portal vein of the liver.
The actual procedure for a patient undergoing an abdominal ultrasound is relatively simple, regardless of the type of scan or its purpose. Fasting for at least eight hours prior to the procedure ensures that the stomach is empty and as small as possible, and that the intestines and bowels are relatively inactive. This also helps the gallbladder become more visible. Prior to scanning, an acoustic gel is applied to the skin of the patient's abdomen to allow the ultrasound probe to glide easily across the skin and also to better transmit and receive ultrasonic pulses. The probe is moved around the abdomen's surface to obtain different views of the target areas. The patient will likely be asked to change positions from side to side and to hold the breath as necessary to obtain the desired views. Usually, a scan will take from 20 to 45 minutes, depending on the patient's condition and anatomical area being scanned.
Ultrasound scanners are available in different configurations, with different scanning features. Portable units, which weigh only a few pounds and can be carried by hand, are available for bedside use, office use, or use outside the hospital, such as at sporting events and in ambulances. Portable scanners range in cost from $10,000 to $50,000. Mobile ultrasound scanners, which can be pushed to the patient bedside and between hospital departments, are the most common comfiguration and range in cost from $100,000 to over $250,000, depending on the scanning features purchased.
Preparation
A patient undergoing abdominal ultrasound will be advised by the physician about what to expect and how to prepare. As mentioned above, preparations generally include fasting.
Aftercare
In general, no aftercare related to the abdominal ultrasound procedure itself is required. Discomfort during the procedure is minimal.
Complications
Properly performed, ultrasound imaging is virtually without risk or side effects. Some patients report feeling a slight tingling and/or warmth while being scanned, but most feel nothing at all.
Results
As a diagnostic imaging technique, a normal abdominal ultrasound is one that indicates the absence of the suspected condition that prompted the scan. For example, symptoms such as abdominal pain radiating to the back suggest the possibility of, among other things, an abdominal aortic aneurysm. An ultrasound scan that indicates the absence of an aneurysm would rule out this life-threatening condition and point to other, less serious causes.
Because abdominal ultrasound imaging is generally undertaken to confirm a suspected condition, the results of a scan often will confirm the diagnosis, be it kidney stones, cirrhosis of the liver, or an aortic aneurysm. At that point, appropriate medical treatment as prescribed by a patient's physician is in order.
Health care team roles
Ultrasound scanning should be performed by a registered and trained ultrasonographer, either a technologist and/or a physician (radiologist, obstetrician/gynecologist). Ultrasound scanning in the emergency department may be performed by an emergency medicine physician, who should have appropriate training and experience in ultrasonography.
Read More ..
Saturday, December 12, 2009
Upper GI Endoscopy
www.gicare.com
Upper GI endoscopy, sometimes called EGD (esophagogastroduodenoscopy), is a visual examination of the upper intestinal tract using a lighted, flexible fiberoptic or video endoscope. The upper gastrointestinal tract begins with the mouth and continues with the esophagus (food tube) which carries food to the stomach. The
J-shaped stomach secretes a potent acid and churns food into small particles. The food then enters the duodenum, or small bowel, where bile from the liver and digestive juices from the pancreas mix with it to help the digestive process.
Equipment
The flexible endoscope is a remarkable piece of equipment that can be directed and moved around the many bends in the gastrointestinal tract. Endoscopes now come in two types. The original pure fiberoptic instrument has a flexible bundle of glass fibers that collect the lighted image at one end and transfer the image to the eye piece. The newer video endoscopes have a tiny, optically sensitive computer chip at the end. Electronic signals are then transmitted up the scope to the computer which then displays the image on a large video screen. An open channel in these scopes allows other instruments to be passed through in order to take tissue samples, remove polyps and perform other exams.
Reasons for the Exam
Due to factors related to diet, environment and heredity, the upper GI tract is the site of numerous disorders. These can develop into a variety of diseases and/or symptoms. Upper GI endoscopy helps in diagnosing and often in treating these conditions:
ulcers --which can develop in the esophagus, stomach, or duodenum; occasionally ulcers can be malignant tumors of the stomach or esophagus difficulty in swallowing upper abdominal pain or indigestion
intestinal bleeding -- hidden or massive bleeding can occur for various reasons
esophagitis and heartburn -- chronic inflammation of the esophagus due to reflux of stomach acid and digestive juices
gastritis -- inflammation of the lining of the stomach
Preparation
It is important not to eat or drink anything for at least eight hours before the exam. The physician instructs the patient about the use of regular medications, including blood thinners, before the exam.
The Procedure
Upper GI endoscopy is usually performed on an outpatient basis. The throat is often anesthetized by a spray or liquid. Intravenous sedation is usually given to relax the patient, deaden the gag reflex and cause short-term amnesia. For some individuals who can relax on their own and whose gagging can be controlled, the exam is done without intravenous medications. The endoscope is then gently inserted into the upper esophagus. The patient can breath easily throughout the exam. Other instruments can be passed through the endoscope to perform additional procedures if necessary. For example, a biopsy can be done in which a small tissue specimen is obtained for microscopic analysis. A polyp or tumor can be removed using a thin wire snare and electrocautery (electrical heat). The exam takes from 15 to 30 minutes, after which the patient is taken to the recovery area. There is no pain with the procedure and patients seldom remember much about it.
Results
After the exam, the physician will explain the results to the patient and family. If the effects of the sedatives are prolonged, the physician may suggest an interview at a later date when the results can be fully understood. If a biopsy has been performed or a polyp removed, the results are not available for three to seven days.
Benefits
An upper GI endoscopy is performed primarily to identify and/or correct a problem in the upper gastrointestinal tract. This means the test enables a diagnosis to be made upon which specific treatment can be given. If a bleeding site is identified, treatment can stop the bleeding, or if a polyp is found, it can be removed without a major operation. Other treatments can be given through the endoscope when necessary.
Alternative Testing
Alternative tests to upper GI endoscopy include a barium x-ray and ultrasound (sonogram) to study the organs in the upper abdomen. Study of the stools, blood and stomach juice can provide indirect information about a gastrointestinal condition. These exams, however, do not allow for a direct viewing of the esophagus, stomach and duodenum, removal of polyps or biopsies.
Side Effects and Risks
A temporary, mild throat irritation sometimes occurs after the exam. Serious risks with upper GI endoscopy, however, are very uncommon. One such risk is excessive bleeding, especially with removal of a large polyp. In extremely rare instances, a perforation, or tear, in the esophagus or stomach wall can occur. These complications may require hospitalization and, rarely, surgery. Quite uncommonly, a diagnostic error or oversight may occur. Due to the mild sedation, the patient should not drive or operate machinery following the exam. For this reason, someone else should be available to drive the patient home.
Summary
Upper GI endoscopy is a simple outpatient exam that is often performed with the patient lightly sedated. The procedure provides significant information upon which specific treatment can be given. In certain cases, therapy can be administered directly through the endoscope. Serious complications rarely occur from upper GI endoscopy. The physician can answer any question the patient has.
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Upper GI endoscopy, sometimes called EGD (esophagogastroduodenoscopy), is a visual examination of the upper intestinal tract using a lighted, flexible fiberoptic or video endoscope. The upper gastrointestinal tract begins with the mouth and continues with the esophagus (food tube) which carries food to the stomach. The
J-shaped stomach secretes a potent acid and churns food into small particles. The food then enters the duodenum, or small bowel, where bile from the liver and digestive juices from the pancreas mix with it to help the digestive process.
Equipment
The flexible endoscope is a remarkable piece of equipment that can be directed and moved around the many bends in the gastrointestinal tract. Endoscopes now come in two types. The original pure fiberoptic instrument has a flexible bundle of glass fibers that collect the lighted image at one end and transfer the image to the eye piece. The newer video endoscopes have a tiny, optically sensitive computer chip at the end. Electronic signals are then transmitted up the scope to the computer which then displays the image on a large video screen. An open channel in these scopes allows other instruments to be passed through in order to take tissue samples, remove polyps and perform other exams.
Reasons for the Exam
Due to factors related to diet, environment and heredity, the upper GI tract is the site of numerous disorders. These can develop into a variety of diseases and/or symptoms. Upper GI endoscopy helps in diagnosing and often in treating these conditions:
ulcers --which can develop in the esophagus, stomach, or duodenum; occasionally ulcers can be malignant tumors of the stomach or esophagus difficulty in swallowing upper abdominal pain or indigestion
intestinal bleeding -- hidden or massive bleeding can occur for various reasons
esophagitis and heartburn -- chronic inflammation of the esophagus due to reflux of stomach acid and digestive juices
gastritis -- inflammation of the lining of the stomach
Preparation
It is important not to eat or drink anything for at least eight hours before the exam. The physician instructs the patient about the use of regular medications, including blood thinners, before the exam.
The Procedure
Upper GI endoscopy is usually performed on an outpatient basis. The throat is often anesthetized by a spray or liquid. Intravenous sedation is usually given to relax the patient, deaden the gag reflex and cause short-term amnesia. For some individuals who can relax on their own and whose gagging can be controlled, the exam is done without intravenous medications. The endoscope is then gently inserted into the upper esophagus. The patient can breath easily throughout the exam. Other instruments can be passed through the endoscope to perform additional procedures if necessary. For example, a biopsy can be done in which a small tissue specimen is obtained for microscopic analysis. A polyp or tumor can be removed using a thin wire snare and electrocautery (electrical heat). The exam takes from 15 to 30 minutes, after which the patient is taken to the recovery area. There is no pain with the procedure and patients seldom remember much about it.
Results
After the exam, the physician will explain the results to the patient and family. If the effects of the sedatives are prolonged, the physician may suggest an interview at a later date when the results can be fully understood. If a biopsy has been performed or a polyp removed, the results are not available for three to seven days.
Benefits
An upper GI endoscopy is performed primarily to identify and/or correct a problem in the upper gastrointestinal tract. This means the test enables a diagnosis to be made upon which specific treatment can be given. If a bleeding site is identified, treatment can stop the bleeding, or if a polyp is found, it can be removed without a major operation. Other treatments can be given through the endoscope when necessary.
Alternative Testing
Alternative tests to upper GI endoscopy include a barium x-ray and ultrasound (sonogram) to study the organs in the upper abdomen. Study of the stools, blood and stomach juice can provide indirect information about a gastrointestinal condition. These exams, however, do not allow for a direct viewing of the esophagus, stomach and duodenum, removal of polyps or biopsies.
Side Effects and Risks
A temporary, mild throat irritation sometimes occurs after the exam. Serious risks with upper GI endoscopy, however, are very uncommon. One such risk is excessive bleeding, especially with removal of a large polyp. In extremely rare instances, a perforation, or tear, in the esophagus or stomach wall can occur. These complications may require hospitalization and, rarely, surgery. Quite uncommonly, a diagnostic error or oversight may occur. Due to the mild sedation, the patient should not drive or operate machinery following the exam. For this reason, someone else should be available to drive the patient home.
Summary
Upper GI endoscopy is a simple outpatient exam that is often performed with the patient lightly sedated. The procedure provides significant information upon which specific treatment can be given. In certain cases, therapy can be administered directly through the endoscope. Serious complications rarely occur from upper GI endoscopy. The physician can answer any question the patient has.
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Saturday, December 5, 2009
Urodynamic study
About urodynamic study
Urodynamic study can help find what's causing urinary incontinence (involuntary leakage) or retention (difficulty in passing urine). It checks how your bladder, the muscle around the neck of your bladder (sphincter) and the tube through which urine flows out of the body (urethra) are working.
The purpose of urodynamic study is to find out whether your:
* symptoms are due to involuntary contractions (squeezing) of your bladder muscles
* bladder pressure is normal during filling and emptying
* bladder capacity is normal
What are the alternatives?
Your doctor may suggest alternative imaging tests, such as plain X-rays of the urinary system, CT (computed tomography) scan or renal ultrasound. Urodynamic study is usually only done if an obvious cause of incontinence or voiding problems isn't found.
Preparing for your procedure
Urodynamic study is usually done as an out-patient procedure. This means you have the test and go home the same day.
You may be asked to keep a record of how much you urinate (called a voiding diary) over three days. You will need to record what type of fluid you drink, when and how much, and the timing and volume of urine output each day. You will need to record when you feel urgency or leak urine. The hospital will give you detailed advice about how to complete a voiding diary beforehand. This diary helps your doctor better understand your bladder problem. You may also be asked to stop any current bladder medication for at least a week beforehand.
You can eat and drink as usual before having urodynamic study. You may be asked to come to your appointment with a full bladder.
At the hospital your nurse may check your heart rate and blood pressure, and test your urine for infection. If you have a urinary infection (known as a urinary tract infection, UTI) your doctor may decide not to proceed with the test and ask you to come back after the infection has cleared.
The procedure may involve X-rays to help your doctor confirm your diagnosis. A radiographer (a health professional trained to perform imaging procedures) usually operates the X-ray machine and produce images on film or in digital format.
You must tell your doctor or radiographer about any medicines you are taking and if you have any allergies, glaucoma or heart disease. If you are a woman of childbearing age, you must tell your doctor or radiographer if you could be pregnant. X-rays are safe for adults, but may harm your developing baby. If you're pregnant, your doctor will discuss alternatives to the procedure.
Your doctor will usually ask you to sign a consent form. This confirms that you understand the risks, benefits and possible alternatives to the procedure and have given your permission for it to go ahead.
About the procedure
Urodynamic study usually takes 15 to 30 minutes.
You will need to remove your lower clothing and put on a hospital gown. You may need to lie back on a special X-ray table, which can be moved into different positions.
Fine tubes (catheters) with sensors attached to the tip are passed into your bladder through the urethra, and placed in your vagina or rectum. You doctor may apply a local anaesthetic gel around the entrance of your urethra beforehand to minimise any discomfort. You may feel the sensation of needing to pass urine as the catheters are put in.
With the catheters in place, the study may include the following tests.
* Filling cystometry - This test measures bladder capacity, bladder contractions and urinary leakage. Your bladder is slowly filled with sterile water. You will be asked to report any sensation you feel. You may be asked to cough, stand or bear down during the test.
* Voiding uroflometry - This test measures the strength of your urinary flow. You will be asked to urinate into a container linked to a computer that records your urine flow. The amount of urine left in your bladder after voiding is also measured.
* Urethral pressure study - This test measures the pressure and flow of urine out of your bladder. You will be asked to urinate while a sensor in the urethra measures the urethral pressure.
* Video cystourethrography - This test helps to identify structural problems in the bladder or urethra. The bladder is filled with contrast fluid (special dye that shows up in X-rays) and X-rays are taken as the fluid is voided.
* Electromyogram - This test helps measure muscle contractions that control urination. Electrode patches may be placed near the rectum or urethra to make the recording. You may be asked to try to tighten or relax your sphincter muscles.
What to expect afterwards
You will be able to go home when you feel ready. You can drive if you wish.
Results
Your results may be discussed with you immediately after the test or at a later date. Alternatively, a report may be sent to the doctor who recommended your test.
Recovering from urodynamic study
Drink plenty of clear fluids over 48 hours to help flush your bladder and reduce your risk of urinary infection.
Contact your GP if you develop any of the following symptoms, as you may have developed an infection:
* severe pain or pain that lasts for more than 48 hours
* high temperature
* burning sensation on passing urine or if your urine starts to smell
* heavy blood-stained urine
What are the risks?
Urodynamic study is commonly performed and generally safe. However, in order to make an informed decision and give your consent, you need to be aware of the possible side-effects and the risk of complications of this procedure.
If the test involves X-rays, you will be exposed to some X-ray radiation. The level of exposure is about the same as the background radiation that you would receive naturally from the environment over 12 to 14 months. X-rays can harm a developing baby. If you are, or think you may be pregnant, tell your doctor before your appointment.
Side-effects
These are the unwanted but mostly temporary effects of a successful procedure.
Side-effects of urodynamic study include:
* feeling some discomfort when passing urine
* feeling mild stinging when passing urine
* some blood in the urine for 24 hours
Complications
This is when problems occur during or after the procedure. Most people are not affected. Complications of urodynamic study are uncommon but can include:
* urinary tract or bladder infection (cystitis) - you may need antibiotics to treat this
* damage to the urethra - this may require treatment with medicines or surgery
* allergic reaction to contrast dye - medicines are available to treat this
The exact risks are specific to you and differ for every person, so we have not included statistics here. Ask your doctor to explain how these risks apply to you.
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Sunday, August 23, 2009
Standards Procedure (Skill) of ECG
Clinical Indications:
Ø Known or Suspected Cardiac Patient
Ø Known or Suspected Tricyclic Overdose
Ø Electrical Injuries
Ø Syncope
Procedure:
a. Assess patient and monitor cardiac status.
b. Administer oxygen per patient condition as tolerated.
c. If patient is unstable, definitive treatment is the priority. If the patient is stable or stabilized after treatment, perform a 12-lead ECG.
d. Prepare ECG monitor and pre-cordial lead cables.
e. Enter patient demographic data.
f. Expose the chest and prep as necessary. Modesty should be considered.
g. Apply chest leads and limb leads as follows:
v RA----right arm
v LA----left arm
v RL----right leg
v LL----left leg
v V1----4th intercostal space at right sternal border
v V2----4th intercostal space at left sternal border
v V3----Directly between V2 and V4
v V4----5th intercostal space at midclavicular line
v V5----Level with V4 at the left anterior axillary line
v V6----Level with V5 at the left midaxillary line
h. Instruct patient to remain still.
i. Press the 12 lead acquisition button on the monitor.
j. If the monitor detects a problem, such as loose leads, bad connection, noisy data, the monitor will alarm. The EMT-P should address the problem.
k. Once acquired, transmit to the appropriate receiving facility.
l. Contact the receiving facility to notify them of the patient and the incoming 12-lead.
m. Monitor and reassess the patient enroute and continue treatment protocol.
n. Attach a copy of the 12-lead with the patient’s record at the hospital.
o. Document the procedure, time, results and findings on the ACR.
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Ø Known or Suspected Cardiac Patient
Ø Known or Suspected Tricyclic Overdose
Ø Electrical Injuries
Ø Syncope
Procedure:
a. Assess patient and monitor cardiac status.
b. Administer oxygen per patient condition as tolerated.
c. If patient is unstable, definitive treatment is the priority. If the patient is stable or stabilized after treatment, perform a 12-lead ECG.
d. Prepare ECG monitor and pre-cordial lead cables.
e. Enter patient demographic data.
f. Expose the chest and prep as necessary. Modesty should be considered.
g. Apply chest leads and limb leads as follows:
v RA----right arm
v LA----left arm
v RL----right leg
v LL----left leg
v V1----4th intercostal space at right sternal border
v V2----4th intercostal space at left sternal border
v V3----Directly between V2 and V4
v V4----5th intercostal space at midclavicular line
v V5----Level with V4 at the left anterior axillary line
v V6----Level with V5 at the left midaxillary line
h. Instruct patient to remain still.
i. Press the 12 lead acquisition button on the monitor.
j. If the monitor detects a problem, such as loose leads, bad connection, noisy data, the monitor will alarm. The EMT-P should address the problem.
k. Once acquired, transmit to the appropriate receiving facility.
l. Contact the receiving facility to notify them of the patient and the incoming 12-lead.
m. Monitor and reassess the patient enroute and continue treatment protocol.
n. Attach a copy of the 12-lead with the patient’s record at the hospital.
o. Document the procedure, time, results and findings on the ACR.
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Electromyography (EMG)
http://www.emedicinehealth.com
Electromyography (EMG)
Electromyography, or EMG, involves testing the electrical activity of muscles. Often, EMG testing is performed with another test that measures the conducting function of nerves. This is called a nerve conduction study. Because both tests are often performed at the same office visit and by the same personnel, the risks and procedures generally apply to both tests.
Muscular movement involves the action of muscles and nerves and needs an electrical current. This electrical current is much weaker than the one in your household wiring.
In some medical conditions the electrical activity of the muscles or nerves is not normal. Finding and describing these electrical properties in the muscle or nerve may help your doctor diagnose your condition.
EMG may aid with the diagnosis of nerve compression or injury (such as carpal tunnel syndrome), nerve root injury (such as sciatica), and with other problems of the muscles or nerves. Less common medical conditions include amyotrophic lateral sclerosis, myasthenia gravis, and muscular dystrophy.
Risks
People usually have a small amount of discomfort during EMG testing because of pin insertion. Disposable needles are used so there is no risk of infection.
During nerve conduction studies, small electrodes are taped to the skin or placed around fingers. You typically experience a brief and mild shock, which may be a bit unpleasant. Most people find it only slightly annoying.
EMG Preparation
No specific preparation is needed for the testing.
During the Procedure
During EMG, small pins or needles are inserted into muscles to measure electrical activity. The needles are different than needles used for injection of medications. They are small and solid, not hollow like hypodermic needles. Because no medication is injected, discomfort is much less than with shots.
* You will be asked to contract your muscles by moving a small amount during the testing.
* With nerve conduction studies, small electrodes will be taped to your skin or placed around your fingers. You typically will experience a mild and brief tingling or shock, which may be a bit unpleasant.
* The person who administers the test will explain the procedure. Often muscle activity is monitored through a speaker during the test, which may make a popping or soft roaring noise. The EMG technician will be looking at an oscilloscope, which looks like a small TV set during the procedure.
* Testing may take 30-60 minutes.
After the Procedure
If you are having this test in a doctor’s office, you will be sent home following the procedure without any restriction of activities. Some people may have minor aches and pains from the testing.
Read More ..
Electromyography (EMG)
Electromyography, or EMG, involves testing the electrical activity of muscles. Often, EMG testing is performed with another test that measures the conducting function of nerves. This is called a nerve conduction study. Because both tests are often performed at the same office visit and by the same personnel, the risks and procedures generally apply to both tests.
Muscular movement involves the action of muscles and nerves and needs an electrical current. This electrical current is much weaker than the one in your household wiring.
In some medical conditions the electrical activity of the muscles or nerves is not normal. Finding and describing these electrical properties in the muscle or nerve may help your doctor diagnose your condition.
EMG may aid with the diagnosis of nerve compression or injury (such as carpal tunnel syndrome), nerve root injury (such as sciatica), and with other problems of the muscles or nerves. Less common medical conditions include amyotrophic lateral sclerosis, myasthenia gravis, and muscular dystrophy.
Risks
People usually have a small amount of discomfort during EMG testing because of pin insertion. Disposable needles are used so there is no risk of infection.
During nerve conduction studies, small electrodes are taped to the skin or placed around fingers. You typically experience a brief and mild shock, which may be a bit unpleasant. Most people find it only slightly annoying.
EMG Preparation
No specific preparation is needed for the testing.
During the Procedure
During EMG, small pins or needles are inserted into muscles to measure electrical activity. The needles are different than needles used for injection of medications. They are small and solid, not hollow like hypodermic needles. Because no medication is injected, discomfort is much less than with shots.
* You will be asked to contract your muscles by moving a small amount during the testing.
* With nerve conduction studies, small electrodes will be taped to your skin or placed around your fingers. You typically will experience a mild and brief tingling or shock, which may be a bit unpleasant.
* The person who administers the test will explain the procedure. Often muscle activity is monitored through a speaker during the test, which may make a popping or soft roaring noise. The EMG technician will be looking at an oscilloscope, which looks like a small TV set during the procedure.
* Testing may take 30-60 minutes.
After the Procedure
If you are having this test in a doctor’s office, you will be sent home following the procedure without any restriction of activities. Some people may have minor aches and pains from the testing.
Read More ..
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