clis oms i fall 2014 block 2. mosby’s anion gap (pages 66-67) a venous blood evaluation of...

CLIs OMS I Fall 2014

Block 2

MOSBY’S

Anion gap (pages 66-67)• A venous blood evaluation of patients with acid-base disorders• Attempts to identify cause of the disorder and also to monitor ongoing therapies for

acid-base abnormality• Test explanation:

• Difference between cations and anions in extracellular space• (sodium + potassium) – (chloride + bicarbonate) Normal: 12 (+/- 4)• Test should be adjusted downwards if potassium is eliminated from test Normal: 16 (+/- 4)• Bicarb is actually venous CO2 not arterial bicarb, because test is venous sample• Determines cause of metabolic acidosis, most acidotic states result in increased AG• The build up of ketoacids and lactic acid will cause increased AG• Albumin is one of the leading factors in increasing AG• Nephrotic syndrome ( decrease in anions) or increased calcium or magnesium will cause

decreased AG • Increased bicarb causes low AG• Hypoproteinemia and increased immunoglobulins can lower AG• Gives a complex metabolic picture along with ABG

• Interfering factors:• Decreasing factors: hyperlipidemia, acetazolamide, lithium, polymyxin B, spironolactone, and

sulindac• Increasing factors: carbenicillin, carbonic anhydrase inhibitors (acetaloamide), diuretics,

ethanol, methanol, penicillin, and salicylate

Anion Gap – Increased and Decreased Values

• Increased Levels:• Lactic acidosis , DKA , alcoholic ketoacidosis , alcohol intoxication,

starvation (b/c of increased ketoacids) , renal failure (b/c non-excretion of organic anions decreases bicarb) , diarrhea (loss of bicarb from GI triact) , hypoaldosteronism ( b/c of decreased H+/Na+ pump activity in distal renal tubule)

• Decreased levels:• Excess alkali ingestion , multiple myeloma , chronic vomiting or

gastric suction (b/c of loss of gastric acid) , hyperaldosteronism , hypoproteinemia ( b/c loss of anionic proteins increases bicarb), lithium toxicity

Arterial blood gases • Monitor patients on ventilators, monitor critically ill

nonventilator patients, establish preoperative baseline parameters, and regulate electrolyte therapy

• pH –log[H+]• Acids normally found in blood: carbonic, dietary, lactic and

ketoacids• Elevated indicates alkalosis• Decreased indicates acidosis• Normal pH: 7.35-7.45 (slightly larger range in infants and

children)• pH (Venous): 7.31-7.41 - It is more acidic b/c it contains more CO2

Blood gases• PCO2• Measure of partial pressure of carbon dioxide in the blood• Measure of ventilation (faster and deeper breathing removes

more CO2) PCO2 is a major medullary drive for respiration.• 10% free floating in plasma, 90% carried by RBCs• Respiratory component of acid-base determination• Co2 and pH are inversely proportional• Normal PCO2 = 35-45 mmHg (again infants and v. young children

wider range)• PCO2 (venous) = 40-50 mmHg• This is a measure of partial pressure, don’t confuse with HCO3-

concentration.

Blood gases• HCO3- (or CO2 content) Concentration• Measure of the metabolic component of the acid-base equilibrium• Regulated by the kidney• Directly proportional to pH (CO2 would be an indirect measure of bicarbonate)• In alkalosis kidneys excrete more into the urine to lower pH (compensating)• Adult Normal HCO3-: 21-28 mEq/mL (infants lower)

• PO2• Pressure of oxygen dissolved in plasma• Indirect measure of O2 content• Determines effectiveness of oxygen therapy• Determines the force of oxygen to diffuse across the pulmonary alveoli

membrane • Low if O2 diffusion difficulties (eg Pneumonia, shock lung, congestive failure)• Low if ventilation/profusion rations are off (under ventilated or over perfused

alveoli)• Normal PO2 = 80-100 mmHg (newborns less)• PO2 (venous) = 40-50 mmHg

Blood gases• Oxygen saturation

• Percentage of hemoglobin saturated with oxygen• As PO2 decreases so does saturation of hemoglobin (think about the sigmoidal shape of the

disassociation curve >75% stat, things are going very badly for the patient)

• Normal Adult/Child O2 saturation = 95%-100%• Oxygen content

• The amount of oxygen in the blood• Nearly all of it is bound to hemoglobin• Arterial: 15-22 vol%• Venous: 11-16 vol %

• Base excess/deficit• Amount of anions in the blood, bicarbonate being the largest. Also hemoglobin, proteins,

phosphates. • Normal Base Excess = 0 +/- 2 mEq/L• Negative base excess indicates metabolic acidosis (eg lactic acidosis)• positive alkalosis (either metabolic or compensation to prolonged respiratory acidosis)

• Alveolar to Arterial O2 difference • Normally should be <10 mmHg

How to interpret ABG levels • 1. Evaluation the pH

• If the pH is < 7.4 acidosis is present• If the pH is > 7.4 alkalosis is present

• 2. Next look at the PCO2 (careful: text same, order different from book)

• A. If the PCO2 is high with acidosis = Respiratory acidosis (primary problem is with decreased breathing eg drugs or lung disease)

• B. If the PCO2 is low with acidosis = Metabolic acidosis (with increased ventilation to blow off of CO2)

• C. If PCO2 is high with alkalosis = Metabolic alkalosis (with compensatory retention of CO2, down ventilation)

• D. If PCO2 is low with alkalosis = Respiratory alkalosis (Primary problem is hyperventilation)• 3. Next look at the bicarbonate ion (HCO3-)

• Respiratory acidosis you would expect to see high HCO3- [kidneys compensating with increased reabsorption]

• Metabolic acidosis you would expect to see a low HCO3- [lack of bicarb is part of primary problem Ex: diabetes, renal failure]

• Metabolic alkalosis you would expect to see a high HCO3- [excess bicarb is part of primary problem Ex: prolonged vomiting]

• Respiratory alkalosis you would expect to see a low HCO3- [kidneys decrease reabsorption to compensate]

Cholesterol• Normal Findings:

Adult: <200 mg/dLChild: 120-200 mg/dLNewborn: 53-135 mg/dL

• -Needed for production of steroids, sex hormones, bile acids, and cellular membranes

• -The main lipid associated with arteriosclerotic disease• -Metabolized by the liver• -75% bound inside LDL and 25% is in HDL• - Main component of LDL (minimal in HDL and VLDL)• - Testing is typically part of a lipid profile (by itself is not an accurate predictor of

heart disease)• - Individual cholesterol levels can vary daily by 15%• -Positional changes affect levels (15% decrease seen in lateral recumbent position,

often seen in hospitalized patients)• -Repeat tests should be done for abnormal values and an average will be

established• -Used to predict risk of CHD within the Framingham Coronary Prediction algorithm

(determines overall risk of ischemic event)

Cholesterol

• Increased levels: liver disease, pregnancy, oorophorectomy, postmenopausal status, familial hyperlipidemias or hypercholesterolemias, hypothyroidism, uncontrolled diabetes mellitus, nephrotic syndrome, xanthomatosis, hypertension, atherosclerosis, biliary cirrhosis, stress

• Drugs that increase levels: adrenocorticotropic hormone, anabolic steroids, beta-adrenergic blocking agents, corticosteroids, cyclosporine, epinephrine, oral contraceptives, phenytoin, sulfonamides, thiazide diuretics, and vit D

Cholesterol

• Decreased levels: liver disease, malabsorption, malnutrition, acute myocardial infarction (6-8 weeks following), advanced cancer, hyperthyroidism, cholesterol-lowering medication, pernicious anemia, hemolytic anemia, sepsis, stress,

• Drugs that decrease levels: allopurinol, androgens, bile salt-

binding agents, captopril, chlorpropamide, clofibrate, colchicine, colestipol, erythromycin, isoniazid, liothyronine, MAO inhibitors, niacin, nitrates, and statins

Creatinine kinase

• Adult/elderly (values higher after exercise): 55-170 units/L (males); 30-135 units/L (females)• Newborn: 68-580 units/L

• Isoenzymes: CK-MM: 100%, CK-MB: 0%, CK-BB: 0%

This test is used to support the diagnosis of myocardial muscle injury…it can also be used to indicate neurologic or skeletal muscle diseases.

CK is predominantly found in heart muscle, skeletal muscle, and brain…CK levels elevate when muscles or nerve cells are damaged:

• Rise within 6 hrs. after damage• Levels peak at 18 hours (if damage is not persistent)• Return to normal in 2-3 days

Interfering Factors: IM injections, strenuous exercise, early pregnancy, muscle massDrugs that cause increased CK levels: alcohol, amphotericin B, ampicillin, anesthetics, anticoagulants, aspirin, colchicine, dexamethasone, lithium, lidocaine, morphine, statins.

Creatinine kinaseElectrophoresis is used to detect the 3 CK isoenzymes:

• CK-BB (CK1): Found predominantly in the brain and lung• CK-MB (CK2): specific for myocardial cells.

• Rise 3-6 hrs. post-infarction, levels peak at 12-24hrs., return to normal in 12-48 hrs.

• Do not usually rise with transient chest pain cause by angina, PE, or CHF.

• Will see a rise in patients with shock, malignant hyperthermia, myopathies, or myocarditis.

• CK-MB levels used to determine the appropriateness of thrombolytic therapy (MI)

• CK-MM (CK3): makes up almost all of the circulatory total CK enzymes in healthy people. Increases in CK-MM suggest skeletal muscle damage.

*See Chart p. 201—levels of Troponin, CK-MB, and Myoglobin post-MI*

Creatine kinase, pp.

CK is the main cardiac enzyme used to detect MI…others used include: Lactic dehydrogenase (LDH), and aspartate amino transferase (AST)

*See Chart p. 201—levels of Troponin, CK-MB, and Myoglobin post-MI*

AVOID IM injections in patients with cardiac disease (they cause elevated CK levels)

Interfering Factors: IM injections, strenuous exercise, early pregnancy, muscle massDrugs that cause increased CK levels: alcohol, amphotericin B, ampicillin, anesthetics, anticoagulants, aspirin, colchicine, dexamethasone, lithium, lidocaine, morphine, statins.

D-dimer• Normal Findings: <0.4 mcg/mL• ELISA and ELFA test, (Enzyme-linked fluorescent immunoassay is faster and more reliable)

• D-dimer is used to identify intravascular clotting by assessing both thrombin and plasmin activity. (Disseminated intravascular coagulation).

• D-dimer is a fibrin degradation fragment that is made through lysis of cross-linked (d-dimerized) fibrin. The D-dimer assay provides a highly specific measurement of the amount of fibrin degradation that occurs…normal plasma does not have detectable amounts of d-dimer fragments.

D-dimer• D-dimer may be used in combination with the Fibrin Degradation

Products assay for high sensitivity and specificity of disseminated intravascular coagulation (DIC).

• Levels of D-dimer will increase during thrombolytic therapy of fibrin clots and can be used to determine the duration of anticoagulant therapy in patients with DVT.

• High D-dimer levels are associated with PE, DVT, sickle cell anemia, and thrombosis of malignancy.

Factor V-Leiden• Normal: Negative FVL• The test is used to diagnose factor V-Leiden thrombophilia

• Factor V is an important factor in reaction 4 (common pathway) of normal hemostasis. The term “factor V-Leiden” refers to an abnormal form of factor V in which there is a specific glutamine to arginine substitution at nucleotide 1619 in the gene of factor V.

• FVL is inactivated 10 times slower than regular factor V due to a mutation in the site where protein C normally binds to deactivate and breakdown factor V. Result: increased thombin generation and a mild hypercoagulable state.

• FVL is the most common hereditary blood coagulation disorder in the US.(5% of Causcasian, 1.2% of Black Americans). Only about 10% of patients with FVL experience a thrombotic event.

• Testing for FVL is sometimes preceded by a screening coagulation test called the activated protein C (APC) resistance test, used to identify the resistance of factor V to activated protein C.

Factor V-Leiden

• Individuals who are candidates for FVL testing include those who have:• Experienced a thrombotic event without any predisposing factors• A strong family history of thrombotic events• Experienced a thrombotic event before 30 years of age• Experienced DVT during pregnancy or while on birth control pills• Had venous thrombosis at usual sites• Experienced an arterial clot

Lipoproteins• Lipoproteins Should be collected after a 12-14 hour fast.• Measured and classified by their density.• Interfering Factors: smoking and alcohol ingestion decrease HDL, binge

eating alter lipoproteins, HDL values are age and sex-dependent, HDL values (similar to cholesterol) decrease for 3 months post-MI, elevated HDL in hypothyroid, high triglyceride levels make LDL calculations inaccurate.

• General Categories:• Chylomicrons-carry TAGs from the intestine à liver, skeletal muscle, adipose tissue• VLDLs- carry newly synthesized TAGs from liver adipose tissue. VLDLs are the

predominant carriers of triglycerides. To a lesser degree, VLDLs are also associated with increased risk of CAD because they can be converted to LDL by lipoprotein lipase in skeletal muscle.

• IDLs- intermediates between VLDLs and LDLs, not detectable in blood• LDLs- carry cholesterol from liver cells of the body. “bad cholesterol”• HDLs- collects cholesterol from the body’s tissues and brings it back to the liver,

protective effect against heart disease. Out of the 5 subclasses of HDL, only 2b is cardioprotective

Lipoproteins• Risk for Coronary Heart Disease Based on Ratio of Cholesterol to HDL• High levels of LDLs are atherogenic…target levels vary according to risk

profile of patient (see p. 359). LDL= total cholesterol- ((TGs/5)-HDL). SGGE divides LDL into 7 classes based on particle size. IIIa and IIIb are the most commonly elevated forms, IVa and IVb are associated with aggressive arterial plaques (nearly all patients with IVa and IVb levels greater than 10% of total LDL have a cardiovascular events within months!)

• LDL patterns have been identified to assess risk of CAD:• (LDLs can be lowered with diet, exercise, and statins)• LDL Pattern A: mostly large LDL particles, no increased risk for coronary artery

disease (CAD)• LDL Pattern B: mostly small LDL particles associated with increased risk for CAD• Intermediate pattern: small and large LDL molecules, carries an intermediate risk.

Lipoproteins• Lipoproteins- accurate predictor of heart disease• -Proteins in the blood whose main purpose is to transport

cholesterol, triglycerides, and other insoluble fats• -Used as markers to indicate the levels of lipids

Risk for Heart Disease Male Female

High 60 mg/dL 70 mg/dL

Moderate 45 mg/dL 55 mg/dL

Low 25 mg/dL 35 mg/dL

Risk of CHD Male Female

½ the average 3.4 3.3

Average (3:1) 5.0 4.4

2x average (moderate) 10.0 7.0

3x average (high) 24.0 11.0

Prothrombin time• Adequacy of extrinsic system and common pathway• Activation of factor X in the presence of factor V and

phospholipid and calcium• Stimulates platelet aggregation and converts fibrinogen to

fibrin in clot stabilization• Tests:• Factors I (fibrinogen), II (prothrombin), V, VII, and X

PT• Hepatocellular liver disease (cirrhosis, hepatitis, neoplastic

invasive processes) Factors I, II, V, VII, IX, X

• Obstructive biliary disease bile necessary for fat absorption decreases A,D,E and K are all fat soluble. II, VII, IX, X all dependent on vitamin K, differentiate from liver disease because it responds to vitamin K

• Coumarin ingestion (warfarin) interfere with vitamin K associated factors; effects long lasting, can be fixed by vitamin K. Monitors warfarin tx.

PT and INR• Evaluate extrinsic and common pathway• Fibrinogen, prothrombin, V, VII, X• Decreased levels: hepatocellular disease affect factors I, II, V, VII, IX, and X• Obstructive biliary disease causes fat malabsorption A, D, E, and K affected• Coumarin (warfarin) ingestion• INR is a stardardized ratio to correct for laboratory, environmental

variations in clotting time, unrelated to sample quality. • Warfarin interferes with vitamin K may be enhanced by aspirin, quinidine,

sulfa, and indomethacin• Barbituates, chloral hydrate and oral contraceptives cause increased

coumarin drug binding decreasing the effects• Alcohol can prolong• Diet high in fat or leafy vegetables may shorten OT• Diarrhea or malabsorption can prolong

Troponins

• Normal Findings: Cardiac Troponin T: <0.2 ng/mL• Cardiac Troponin I: <0.03 ng/mL

• This test is performed on patients experiencing chest pain to determine if the pain is caused by cardiac ischemia. It is a specific indicator of cardiac muscle injury.

• Cardiac troponins are biochemical markers for cardiac disease and can actually be used in patients with unstable angina to determine the likelihood of a cardiac event. Their sensitivity and specificity are similar to that of CK-MB (but troponins are even more sensitive)—Cardiac troponin levels become elevated as early as 3 hrs. post-myocardial injury and stay elevated for 7-14 days (7-10 days for troponin I, 10-14 days for troponin T)

• ELISA method w/monoclonal Abs—fast, can be done bedside.

Troponins• If reinfarction is suspected, troponins may not be as helpful

because levels could still be elevated from the first ischemic event. [Stay elevated longer than CK-MB]

• Cardiac troponins are useful for the following situations:• Evaluation of patient with unstable angina• Detection of reperfusion associated with coronary recanalization• Estimation of MI size• Detection of perioperative MI• Evaluation of severity of PE• Congestive heart failure

• Interfering factors: Troponin T levels are falsely elevated in dialysis patient.

Oximetry• >95% is normal

• Monitors arterial oxygen saturation in patients at risk for hypoxemia. Surgery, cardiac stress testing, mechanical ventilation, heavy sedation, lung function testing or trauma

• Non-invasive measures how many hemoglobin have oxygen attached to them

• Fetal oxygen saturation monitoring: if heart is in distress but saturation is fine you can avoid c-section, placed on cheek between 30 and 70%

• Interfering factors:• Falsely elevated in carboxyhemoglobin poisoning• Severe anemia• Nail polish (can put monitor on pt’s ear)

Radiology, Ch 1

• Be familiar with the different kind of views and when you might use Lateral, versus AP, versus PA• Eg, PA and AP have similar appearances, but difference in

magnification of the heart• AP is the standard portable technique w/ the pt sitting or supine

• The density of the object determines how much of the x-ray beam will be absorbed or attenuated. As the density of an object increases, fewer x-rays pass through it.

• Table 1.1-Basic radiograph film densities or appearances• Radiographic films, photographic films and the currently used

phosphor plates for digital radiography all respond in a similar manner to light and x-rays

Radiology, Ch 1• Computed radiography (CR) or digital radiography (DR) is the process of

producing a digital radiographic image; instead of film, a special phosphor plate is exposed to the x-ray beam. • The intensity of the emitted light depends on local radiation exposure

Contrast media: The use of intravascular pharmaceuticals to differentiate between normal and abnormal tissues, to define vascular anatomy, and to improve visualization of some organs (use chemically bound iodine)• Generally, there is a difference in uptake between normal and abnormal

tissues; the whiter the contrast media appears is referred to as enhancement

• There are complications using high-osmolar contrast agents in infants and individuals w/ compromised renal function• Vomiting, pain at injection site, respiratory sx, urticarial, generalized burning

sensation • Low osmolar contrast agents reduces these, but not for pts w/ nephropathies;

alternatives should be sought for pts w/ DM, vascular dz or renal dysfx

Radiology, Ch 1• Uses for iodinated compounds: angiography, myelography, arthrography, CT

• Angiography: injection of iodinated contrast media directly into a vein or artery via a needle/catheter• Arthrography: injection of contrast media or air into a joint; less important since the invention of CT and

MRI• Air can improve contrast

• Myelography: placement of contrast media in the spinal subarachnoid space, especially by LP; useful for dx of dz near the spinal canal/cord • Also generally less useful since the invention of CT/MRI

• Barium is used for contrast in the GI tract (introduced by swallowing, an intestinal tube, or an enema); called a double-contrast study• Safer, better tolerated, sensitive, specific; lower concentration, not volume can be used for bowel

visualization in CT• Barium studies are contraindicated if there is any potential for extravasation of the barium into the

mediastinum or peritoneum• Use water-soluble contrast agents in this case

• Standard iodinized compounds are NOT used in MRI• Use gadolinium; other medals like iron oxide• Gadolinium does NOT produce an MR signal but causes changes in local magnetic fields by inducing TI

shortening in tissues where it has localized• Useful for imaging tumors, infx, cerebral vascular accidents• Lesions will be whiter than the surrounding tissues• Gadolinium is low-risk for rxns, but can cause a severe connective tissue disorder called nephrogenic

sclerosing fibrosis; usually only happens in pts on dialysis or creatinine clearance e< 30 mg/DL

Radiology, Ch1• CT-sectional anatomy imaging in the sagittal, coronal, axial planes (Fig 1.7)

• Looks at “slices of bread” as opposed to the “whole loaf”)• CT images are produced by a combination of x-rays, computers and detectors

• Pts generally don’t have problems w/ breath holding since images only take a few seconds

• Average scan takes 10-20 minutes• See figs 1.9-10• As in a radiography, the amount of X-ray beam that passes through each slice is inversely

proportional to the density of the tissues• X-rays strike detectors, and the detectors convert incident x-rays to an electron stream;

this stream is digitized into CT units or “Hounsfield” units• Density principles are the same as radiography; one major difference is that a radiograph

displays the entire anatomic structure, whereas a CT image visualizes “slices”• Can be accomplished w/ or w/o contrast-contrast will highlight pathologic tissues

• Contrast not needed for intracerebral hemorrhage, suspected fracture, or fracture fragment within a joint

• Contrast used for evaluating liver, kidney, and brain for suspected neoplasms• Table 1.2-indications for CT imaging• Helical-/Spiral CT; patient continuously moves through the gantry (see Fig 1.11)

Radiology, Ch 1• Multislice/Dynamic CT-multiple contiguous rows of detectors

w/ only one rotation around the X-ray tube around the pt; large volumes can be scanned at one time• Especially beneficial in CT angiography, dynamic CT• Table 1.3-advantages and disadvantages of multislice CT

• Dual Source: 2 different x-ray energies that originate from a single tube; use multiple detectors and helical scanning• Gray value in CT images dependent on density, thickness, and

energy of x-rays (same object could have different gray values depending on if you used hih versus low energy)

• Dual energy applications: direct removal of bone for angiographic imagine, plaque characterization, lung perfusion, identifying tendons, ligaments, assessment of tissue composition

• Radiation dose is a concern using dual-source scanners

Radiology, CH 1• MRI-essentially the imaging of photons; displays anatomy in the axial, sagittal and coronal plane;

slice thickness varies between 1 and 10 mm • Although the magnetic fields are generally believed to be harmless, caution should be used in the

first trimester (teratogenic, possible acoustic damage)• Can be a problem for pts w/ claustrophobia• Table 1.4 and 1.5• Hydrogen protons absorb the broadcast radio wave energy and resonate; as the protons decay back

to normal state and relax, they continue to resonate and broadcast radio waves that can be detected by a radio wave receiver set to the same frequency as the broadcast radio waves and the H+ spin frequency• Bottom line: there are many H+ atoms/protons in fat-> the image will be very bright; bone will be black

• Radio wave signal intensity is determined by the number of H+ atoms and the T1/T2 relaxation times• T1-if listening early during decay after radio signal discontinued• T2- listening late; water will be a lighter gray and fat appears gray

• Table 1.6• T1 used for anatomic information; T2 used for pathology because pathology has + water/hydrogen

and will light up well• T1 has better resolution; T2 has better contrast• To differentiate between CT and MR; look at the fat; subcutaneous fat will be black on CT and white

on MRI; bones will have a gray medullary canal and white cortex on radiographs and CT images; on TI MR all of the bone medullary cavities will be white and bone cortex will be black

Radiology, Ch 1• MRA-non-interventional study to image vessels w/o needles,

catheters, contrast media (though gadolinium could be used)

• Flowing blood will be black, but special imagine techniques can light it up

• 3D images of vasculature• Imaging arteries/veins in head and neck, abdomen, chest, and

extremities• F-MRI• Assesses brain/cardiac function as oxygenated/deoxygenated

blood cause variations• Identifies areas that are active/inactive as working areas of the

brain consume more oxygen; changes in hemoglobin oxygenation= BOLD method; Images are T2-weighted

• Good for cognitive tests

Radiology Ch 1• Functional Cardiac MRI- measures left ventricular volume and ejection

fraction• Delayed contrast enhancement can distinguish infarct from normal

myocardium (bright signal=regions of infarct/scar)• Diffusion-Weighted MRI• Sensitive to cell injuries of multiple etiologies• Used in the diagnosis of ischemic stroke, can reliably detect hypoxic

ischemia within minutes of symptom onset• Susceptibility-weighted MRI-sensitive to venous blood hemorrhage and

iron storage; useful for assessing TBI, stroke, hemorrhage, MS, tumors• Magnetic Resonance Spectroscopy-metabolite concentrations in the

body; protons from water are suppressed so that NAA, choline, creatinine etc can be detected. Used to evaluate lesions to determine cancer, since cancer has shown and elevation of choline and a reduction in NAA. Also used for stroke imaging and inflammatory dz

Radiology Ch 1• Ultrasonography-Table 1.7 and 1.8• Safe, painless, inexpensive, well-tolerated• Produces sectional images in multiple planes (like CT and MRI)• Solid organs usually have a homogenous echo pattern; fluid filled

organs have fewer “internal echoes”• Digitizes sound waves, converting images to black, white and gray

Radiology 101:Pages 25-32Reading frontal chest x-ray• Designed to look at lungs, not trauma to the ribs etc.• R marker should be on your left side• Glance over the image for any obvious abnormality always

look at your four corners• Anterior posterior and posteroanterior• Start at top and make sure trachea is midline• Move to heart, transverse diameter of cardiac silhouette

should not be more than 50% transverse diameter of thoracic cage

• Greater the distance between and object and film, the greater the magnification

Radiology 101:Frontal chest X-ray (continued)• Right heart convex, left cardiac border at the top should be

concave• Left ventricle makes up left heart• SVC makes straight right border• In enlargement left superior border becomes convex• Left enlargement cardiac apex moves down and out• Right enlarges right border is more protuberant• Left and right pulmonary arteries form hilar shadows, left

should be more cephalad• Aorta forms knob• Aortopulmonary window between knob and pulmonary

artery shadow; should be concave or suspect mass or adenopathy

Radiology 101:Pages 25-32Frontal chest X-ray (continued)• Mediastinum shadow is caused by great vessels and vascular

pedicle• Pedicle extends from thoracic inlet to base of heart; right

border is SVC left is aortic knob• Divide lungs into horizontal thirds• Domed diaphragm with right side higher than left• Lateral costophrenic angles should be sharp and acute• Look at lower cervical spine and ribs• Ribs we see are posterior arcs anterior ribs are angled

downward

Radiology 101:Lateral radiograph• Right ventricle is anterior border• Left ventricle is inferior-posterior cardiac border• Left atrium forms superior-posterior cardiac border• IVC can be seen as it enters from abdomen• If left ventricle is 2 cm or more posterior to IVC then it is

enlarged• Evaluating hila left is posterior to line drawn down from

tracheal air column and one third the size of the right• Silhouette sign when two objects of similar density are in

direct juxtaposition interface or borders are lost

DRUGS TO KNOW

Drug Uses Side effects Contraindications Therapeutic considerations

Aspirin (ASA)

MOA-Inhibits synthesis of prostaglandin by cyclooxygenase; inhibits platelets aggregation; has antipyretic (anti-fever) and analgesic activity. Metabolized by the liver.

Prophylaxis against transient ischemic attack, MI, acute coronary syndrome, prevent reocclusion, arthritis, mild pain or fever

GI bleeding, acute renal insufficiency, thrombocytopenia, Reye dz, asthma, tinnitus, dyspepsia, occult bleeding, prolonged bleeding, rash

NSAID induced sensitivity, chickenpox of flu like symptoms, G6PD deficiencyBleeding like hemophilia, von Willebrand thrombocytopenia

Inhibit both Cox 1 and 2Use cautiously with GI bleeds impaired renal function, vit K deficiency, purpura, hepatic impairment


Atenolol

MOA: Blocks response to beta-adrenergic stimulation; cardio selective for beta 1 receptors at low doses with little to NO effect on beta two (safer in asthmatics) Limited metabolization in liver.

Beta-blocker (B1 specific)

HTN, angina, thyroid storm, HF AV block, bradyarrythmia, sedation, decreased libido, mask hypoglycemia, depression, dyspnea, wheezing

Bronchial asthma, COPD, cardiogenic shock, decompensated heart failure, 2nd and 3rd degree AV block, severe sinus bradycardia

Beta one selective adrenergic antagonists


AtorvastatinPg 330

MOA: HMG-COA reductase inhibitor, inhibits rate-limiting step in cholesterol biosynthesis by competitively inhibiting HMG-COA reductase

Class: Inhibitor of cholesterol synthesis (Statin)Mech: inhibits HMG-CoA reductaseIndications:• Hypercholesterolemia• Familial

hypercholesterolemia• Coronary

atherosclerosis• Prophylaxis for coronary

aterosclerosis

• Myopathy-increased risk

• Rhabdomyolysis• Hepatotoxicity• Abdominal pain

(constipation, diarrhea, nausea)

• Headache

• Active liver disease• Pregnancy and lactation

• Up to 60% dec. in LDL• 10% HDL increase• 40% Triglyceride dec.• Drug of choice

for lowering LDL, one of the most potent

• Metabolism by P450 3A4

• Combo with bile acid sequestrant yields lower LDL

• Co-admin with Niacin-> inc. risk of myopathy

• Co-admin with gemfibrozil can induce rhabdomyolysis

Drug Clinical app Adverse affects Contraindications Therapeutic considerations

Atropine

MOA: Antimuscarinic; inhibits action of acetylcholine at parasympathetic sites in smooth muscle, CNS, and secretory glands. Increases cardiac output and dries secretions. Metabolized: Liver

Anticholinergic Agent, Anticholinesterase overdose, bradycardia, excessive salivation and mucus production during surgery

“No See, No Pee, No Spit, No Sh*t” Blurry vision, xerostomia (dry mouth), constipation, urinary hesitancy, increased IOP, loss of taste, hypotension, confusion, coma, ataxia, insomnia, headache,

Actions of PNS inhibited

Narrow Angle glaucoma marginal nicotinic effect; more effective at reversal of exogenous rather than endogenous cholinergic activity


Clopidogrel (Plavix)

MOA: Inhibitor of adenosine (ADP)- induced pathway for platelet aggregation.

Metabolized in liver by CYP450 enzymes.

ACS, recent MI, stroke, peripheral artery disease, CAD, cardioembolic stroke

1-10% URI, chest pain, headache, flu like syndrome, arthralgias, pain, dizziness, diarrhea, depression, rhinitis, rash, UTI <1% neutropenia, acute liver failure, TTP, hypotension, hepatitis, myalgia, eczema

Active bleeding disorder Needs loading dose. Less side effects tha ticlopidne


Eptifibatide (integrelin)- antiplatelet agent

MOA: blocks binding of fibrinogen & von willebrand factor of glycoprotein IIB/IIIA receptor on platelet surface.

Acute coronary syndrome, percutaneous coronary intervention

Major bleeding, intracerebral hemorrhage, hypotension, bleeding

History of bleeding, recent major surgery, recent stroke, intracranial hemorrhage, uncontrolled hypertension

Don’t give with second , second anti GIIb-IIIa agent, minimize arterial and venous puncture, synthetic peptide as parenteral


Heparin- Anticoagulant

MOA:

Low dose: inactivates factor Xa and inhibits conversion of prothrombin to thrombin

High dose: inactivates factor IX, X, XI, & XII and thrombin and inhibits conversion of fibrinogen to fibrinAlso inhibits activation of factor VIII

Prevent embolism, thrombosis, prevent systemic embolism with MI, unstable angina, open heart surgery, DIC, maintain patency IV cath

Hemorrhage, heparin induced thrombocytopenia, hypersensitivity, prolonged clotting time, mucosal ulceration, hematoma

Heparin induced thrombocytopenia, active major bleeding, bleeding tendencies, open ulcerative wounds, conditions that increase capillary permeability, severe HTN, bacterial endocarditis

Unfractionated causes thrombocytopenia more than LMW, antihistamines, cardiac glycosides, nicotine and tetracycline affect abilityCephalosporins, penicillins, oral anticoagulants, platelet inhibitors may increase affectsDon’t use ginger, garlic, ginkgo


Metoprolol (Lopressor) – Beta Blockers, Beta 1 selective

MOA: Blocks response to beta-adrenergic stimulation; cardio selective for beta 1 receptors at low doses with little to NO effect on beta two (safer in asthmatics) [B2 are in bronchiole smooth muscle, blocking causes bronchoconstriction]

Metabolized in liver by

CYP2D6.

AMI, CHF, HTN, Angina, Hyperthyroidism, Acute Tachy,

Side Effects: 1-10% Dizziness, headache, tiredness, depression, diarrhea, pruritus, dyspepsia, heart failure, wheezing, nausea

Asthma or COPD, cardiogenic shock, Decompensated cardiac failure, 2nd & 3rd degree AV

Beta 1 selective adrenergic antagonists


Ramipril (Altace) – ACE Inhibitor “End in pril”

MOA: Competitively inhibits angiotensin-converting enzymes, resulting in decreased plasma angiotensin II concentrations; BP may be reduced in part through decreased vasoconstriction increased renin, activity, and decreased aldosterone secretion; increases renal blood flow

Hypertension, heart failure, diabetic nephropathy, myocardial infarction

>10% Cough (if cough switch to an ARB), hypotension, 1-10% headache, angina, dizziness, N/V, postural hypotension, syncope, vertigo, <1% angioedema

Hx of angioedema, bilateral renal artery stenosis [They depend on RAA axis for renal perfusion], renal failure, pregnacny

3 patterns of metabolism: 1) active drug --> active metabolite 2)prodrug -->active drug 3) active drug and excreted unchanged. Cough and angioedema are caused by bradykinin action: potentially life-threatening. Delay progression of cardiac contractile dysfunction in heart failure and after MI, and delay progression of diabetic nephropathy

Drug Clinical app Adverse effects Contraindications Therapeutic considerations

Simvastatin(Zocor) – Lipid Lowering Agent, Statin

MOA: HMG-COA reductase inhibitor, inhibits rate-limiting step in cholesterol biosynthesis by competitively inhibiting HMG-COA reductase

Hypercholesteremia, familial, coronary atherosclerosis, prophylaxis for coronary atherosclerosis

Myopathy, rhaddomyolysis, hepatotoxicity, dermatomyositis, abdominal pain, constipation, diarrhea, nausea, headache

Active liver disease pregnancy and lactation

Lowering LDL metabolized by P450, 3A4 inhibitors increase risk of myopathy, combo with bile acid sequestrant or cholesterol absorption inhibitor additive decrease in LDL, combo with niacin maybe used in high LDL and low HDL increases risk of myopathy, gemfibrozil decreases statin clearance induce rhabdo


Tissue plasminogen activator (t-PA) (Alteplase, Activase) – Thrombolytics

MOA: Recombinant human tissue-type plasminogen activator (t-pa); produces local fibrinolysis. Promotes thrombolysis by converting plasminogen to plasmin which degrades fibrin and fibrinogen.

AMI = acute MI, PE, Acute Ischemic Stroke

pulmonary edema, arterial embolism, bleeding, DVT, hypotension, intracranial hemorrhage, stroke, fever, chills, N/V, sepsis, shock

Internal bleeding, intracranial/spinal trauma, surgery, masses, recent stroke, uncontrolled hypertension

Binds to newly formed thrombi with high affinity, causing fibrinolysis at the site of a thrombusCan generate a systemic lytic state and cause unwanted bleeding

Drug Clinical app Adverse effects Contraindications Therapeutic considerations

triamterene/Hydrocholorothiazide (Maxide,Dyazide) – Thiazide Combos, HTN

Triamterene – Direct effect on renal distal tubule to inhibit Na reabsorption. Inhibits Na/K-ATPase, decreases Ca and MG and hydrogen excretion =Postassium sparing diuretic

HCTZ- inhibits Na reabsorption in distal renal tubules; results in increased excretion of Na and water also K and H ions. -is a sulfa drug

HTN, adjunct in edema states associated with HF, cirrhosis, renal dysfunction, corticosteroid and estrogen

Arrhythmia, stevens-johnson, pancreatitis, hepatotoxicity, SLE, hypotension, alkalosis, vasculitis, photosensitivity, electrolyte abnormalities, impotence, restlessness, blurrred vision, headache, hyperglycemia, hyperuricemia

Anuria, hypersensitivity to sulfonamides, co administration with agents that prolong QT

First line in treating HTN, diminish hypercalcuria in patients at risk for nephrolithiasis, decreases glucose tolerance may unmask diabetes, don’t use with antiarrhythmic


Warfarin (Coumadin) – Anticoagulants

MOA: Interferes with hepatic synthesis of vitamin K dependent clotting factors II, VII, IX, & X as well as proteins C and S.

Venous Thrombosis, DVT, Afib, Cardiac Valve Replacement, Post MI

1-10% Intraocular Hemorrhage, UNK Freq – abd pain, rash, pruritus, tissue necrosis, headache, lethargy, anemia, hemorrhage, fever, purple toe syndrome,

Pregnancy, Hemorrhage, Bleeding tendency, uncontrolled Hypertension

Monitor with PT/INR. Many drug-drug interactions, never give to pregnant woman, can cause skin necrosis, receive fresh frozen plasma if hemorrhaging occurs

clis oms i fall 2014 block 2. mosby’s anion gap (pages 66-67) a venous blood evaluation of...

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