Evidence Based Practice Flashcards
Types of observational studies
Cohort studies
Case-control studies
Cross-sectional studies
Evidence based medicine (EBM) approaches a clinical dilemma as a clinical question using what pneumonic?
PICO
P-patients problem
I- clinical intervention
C- comparison of the intervention with at least one alternative
O- desired outcome used to compare interventions
Margination
A process in which white blood cells, or leukocytes, relocate from their normal central location in the bloodstream to the periphery along the endothelium wall. As margination progresses, leukocytes adhere to endothelial cells, before migrating from the blood to the tissue, where they are responsible for limiting the harmful stimuli and beginning the process of repair.
What type of questions is the PICO model best applied to?
Foreground questions (specified knowledge questions that affect clinical decisions)
Inflammation
Reaction of vascularized tissue in the body to local injury or insult.
Excessive inflammation can be pathogenic
Clinical signs: redness, fever, swelling, pain
Vascular and cellular components of inflammation
Vascular- following injury, the body increases blood flow to the site through dilation of the arterioles. This ultimately leads to dilation of the capillaries and venules. This allows increased permeability of macromolecules into the tissue space. This causes swelling/edema.
Cellular- as fluid is lost in the tissue space, large amounts of RBCs, WBCs, and platelets remain behind causing blood viscosity to increase. This increase in viscosity causes margination.
Histamine
Mediator of inflammation
Stored in granular tissue of mast cells
Once released, produces vasodilation and increased vascular permeability
Factor XII (Hageman factor)
Mediator of inflammation
Stored in an inactive form in plasma
Once activated, this plasma protein triggers the activation of 4 different cascades of systems important to inflammation and repair (coagulation cascade, kinin cascade, fibrinolytic cascade, complement cascade)
Coagulation cascade
leads to thrombin formation, which converts fibrinogen into fibrin, ultimately leading to clot formation
Kinin cascade
Leads to the production of bradykinin. Bradykinin is a peptide that causes vascular dilation and increases permeability
Fibrinolytic cascade
Involves the conversion of plasminogen into the active protease plasmin. Plasmin has two important functions: degradation of fibrin clots and activation of the complement cascade
Complement cascade
Has many important functions. Produces proteins that form the membrane attack complex, which attacks harmful microorganisms. Additional activated proteins in this cascade are mediators of inflammation causing vasodilation, increasing vascular permeability, promoting chemotaxis and phagocytosis, and initiating histamine release.
Arachidonic acid
A fatty acid found in many cell membranes. Two different pathways metabolize arachidonic acid, which results in the production of potent inflammatory mediators.
Prostaglandins and thromboxanes are produced from arachidonic acid through the cyclooxygenase pathway
Prostaglandins
Induce vasodilation and increase vascular permeability
Thromboxanes
Facilitate platelet aggregation, which is important to the healing and repair process.
Lipoxygenase pathway
results in the production of leukotrienes. Leukotrienes initiate chemotactic activities for WBC, causing vasodilation, and increase vascular permeability
Hemodynamics
Defined as the function of blood flow or circulation and the forces involved. Alterations or disturbances in the normal pattern of blood flow can be harmful to the organs and tissues of the body.
Edema
The abnormal accumulation of fluids in the interstitial spaces of cells or tissues
Water composition in the body
Intracellular compartment- contains approximately 2/3rds of total body water
Extracellular compartment- stores the remaining 1/3rd of total body water
The extracellular compartment is further divided into the interstitial space and plasma space, which are separated by the capillary wall.
What is normal exchange of water controlled by?
Controlled by hydrostatic and osmotic pressure, which is regulated by plasma proteins. Disruption of this normal exchange explains the etiology of edema
Causes of edema
Increased hydrostatic pressure Decreased osmotic pressure Increased vascular permeability caused by inflammation Obstruction of a lymphatic channel Sodium retention
Congestion
A passive process in which the drainage of blood from a given area is interrupted. An example of congestion can be seen in valvular stenosis. In this disorder, blood volume is increased in the cardiac chamber preceding the valve that is failing to open properly.
Increase in blood volume
Hyperemia
An active process in which blood flow is increased to a given area. An example of this process can be seen in acute inflammation.
Increase in blood volume.
Hemorrhage
the loss or escape of blood from the circulatory system. Accumulation of this lost blood may be external or enclosed within the tissue space of the body.
Hematoma
Referred to the accumulation of blood within the tissues and can range in severity for mild (bruise) to more severe (subdural hematoma)
Petechiae
Pinpoint hemorrhages seen most commonly on dermal or mucosal areas
Purpuras
Widespread hemorrhages slightly larger than petechiae usually found under the dermal surface
Ecchymoses
Larger, often blotchy hemorrhages that also are found on mucosal or dermal areas
Thrombosis
The pathologic process of formation of a blood clot within the circulatory system. The formed clot is referred to as a thrombus.
Virchows triad
Thrombus formation
- ) Decreased blood flow
- ) Injury or abnormality of the endothelial wall of the vessel
- ) Changes to the normal properties or processes of blood coagulation
Most thrombi are formed because of what?
decreased blood flow
On the venous side, blood pressure is lower (as compared to the arterial blood)
Embolism
the lodging of a detached mass, or embolus, from one area of the bloodstream to another. Most emboli are formed from blood clots and are referred to as thromboemboli
Infarction
the process of forming an ischemic necrosis within a tissue or organ
Shock
A serious condition involving decreased perfusion of tissues and organs because of inadequate blood flow. Signs and symptoms can include cold, mottled skin, mental status changes, and oliguria
Hypovolemic shock
Due to an inadequate volume of circulating blood most commonly caused by hemorrhage or trauma. In hypovolemic shock, cardiac output (CO) is reduced because of decreased venous return and systemic vascular resistance (SVR) is high because of compensatory vasoconstriction
Distributive shock
Due to an inadequate volume of circulating blood; however, fluid is not actually leaving the body as is seen in hypovolemic shock. Infections (septic), anaphylaxis (anaphylactic shock), and medications (neurogenic shock) are common causes of circulatory vasodilation leading to this type of shock.
CO usually is normal to elevated and SVR is reduced in distributive shock
Cardiogenic shock
Caused by cardiac malfunction and is most commonly seen in patient suffering myocardial infarction or cardiac arrhythmias. CO is reduced and SVR is increased in cardiogenic shocl
Shock can potentially progress through which 3 stages?
Nonprogressive stage-reflex neurohumoral mechanisms are activated, and normal circulation is restored
Progressive stage- tissue and organs remain hypoperfused, thereby increasing damage and decreasing likelihood of compensation. This condition can be seen in cases with severe blood loss.
Irreversible stage
Agenesis
the failure of organ formation during embryo formation
Aplasia
failure of organ or tissue development
Hyperplasia
the enlargement in the size of an organ or tissue because of cellular proliferation
The maintenance of blood pressure depends on what 2 factors?
Cardiac output and systemic vascular resistance
What is HTN most commonly caused by?
Increases in SVR
ANP
Atrial natiuretic peptide is secreted by the atria of the heart in response to increased blood flow. ANP increases urinary excretion of sodium and water thereby causing a decrease in blood pressure.
Nitric oxide
Potent vasodilator released by the endothelial cells in response to changes in blood pressure. Oxidative stress has been suggested to cause a deficiency in nitric oxide, and thus HTN
Endothelin
Vasoconstricting substance. Overstimulation can cause HTN
Insulin is necessary for
the transport of glucose into cells, where it is stored as glycogen to be used for energy
Insulin is produced
by the beta cells of the islets of Langerhans of the pancreas
In addition to glucose uptake, insulin stimulates
amino acid uptake, and thus, protein synthesis by muscle. It can also stimulate fatty acid storage in adipose tissues.
Symptoms of DM
polyuria, polydipsia, polyphagia, fatigue, weight loss
How do most cases of T1DM happen?
Most result from an immune-mediated destruction of beta cells of the pancreas by T-lymphocytes.
The majority of calories should come from
Fruits, vegetables, whole grains, legumes, and nuts
Intake of red meats and saturated fats should be limited
Calories recommended intake
1,800-2,000 kcal/day
Carb recommended intake
45-65% of total daily calories
