Flashcards in Med Surg Exam 2 Deck (165)
What do bases bind with?
Free H+ ions
What is a buffer?
any mechanism that resists changes in pH by converting a strong acid or base to a weak acid or base
What are some examples of chemical buffers?
carbonic acid-sodium bicarbonate system
What is the most active buffer system?
Carbonic acid-sodium bicarbonate system
How do you keep acids in balance with bases?
acids must be neutralized and excreted
What are two neutralizers?
CO2 (acid) and HCO3 (base) are neutralizers
What is normal acid base balance?
20 bicarbonate ions (HCO3) to 1 carbonic acid (H2CO3)
What must be controlled to maintain the acid base balance ratio?
Both bicarbonate ions and carbonic acid must be controlled.
How is CO2 continuously formed?
intracellular metabolic processes (cellular respiration)
Increased respiration means? (resp. compensation)
More CO2 produced
Decreased respiration means?(resp. compensation)
Less CO2 produced
How quickly does respiratory compensation occur?
within minutes (to preserve acid base balance)
How does the respiratory system regulate H+ concentration?
CO2 excretion (exhalation)
CO2 retention (to prevent alkalosis)
How does the renal system help acid base balance?
Excrete H+ ions
Reabsorbs (conserves) bicarbonate
Forms new bicarb (carbonic acid loses H+ ions)
What is the carbonic acid disassociation formula?
CO2 + H2O↔️H2CO3↔️H+HCO3
How do the kidneys compensate in acidosis?
excreting H+ (K+ stays) "If you're staying, I'm outta here"
How do the kidneys compensate in alkalosis?
saves H+ (K+ goes) "i'm staying, get outta here"
Is renal compensation a stronger or weaker mechanism than respiratory compensation?
Stronger. It takes longer to respond 24-48 hours.
When is renal compensation fully stimulated?
When the Acid/Base imbalance lasts for several hours or several days
What causes respiratory acidosis?
Accumulation of CO2
COPD with CO2 retention (cant blow off co2)
Hypoventilation due to: sedation, overdose, anesthesia, change in LOC Closed head injury CVA
What are signs of respiratory acidosis?
headache, confusion, drowsiness, dyspnea, muscle weakness, elevated blood K+
What are causes of respiratory alkalosis?
Hypoxia (trying to get O2)
What are signs of respiratory alkalosis?
What are causes of metabolic acidosis?
diabetic ketoacidosis, end stage renal disease
lactic acidosis & starvation
What are signs of metabolic acidosis?
changes in LOC
What are causes of metabolic alkalosis?
overuse of antacids
What are signs of metabolic alkalosis?
Decrease in Ca++
decrease in respirations
arrythmia r/t decrease in K+
How long after exposure does it take for the HIV virus to show up on a diagnostic test?
What is the diagnostic test ELISA used for?
The initial screening for HIV
Why is ELISA test used if there is a possibility of a false positive?
Because the test is inexpensive and mostly accurate. Anyone with a positive result must have additional testing to confirm the diagnosis
What is the Western Blot test used for?
To confirm the diagnosis of HIV when the results of an ELISA are positive
How does the ELISA test work?
Pt's serum is mixed with HIV grown in a culture. If the pt has antibodies to HIV, they bind to the HIV antigens and can be detected (a positive test)
How does the Western Blot test work?
Detects serum antibodies to four specific major HIV antigens. The presence of antibodies to at least two major HIV antigens is a positive test.
Three ways most common for transmission of HIV
Sexual, parenteral, perinatal
What do the results of a bone marrow aspiration or biopsy show?
Reflects degree and quality of bone marrow activity....indicates what different cell types/ quantity / proportion of each are present....can confirm spread of cancer cells from other tumor sites
Does bone marrow aspiration or biopsy require informed/signed consent?
What is obtained in a bone marrow aspiration?
Cells and fluid suctioned from the bone marrow
What is obtained in a bone marrow biopsy?
Solid tissue and cells obtained by coring out an area of bone marrow with a large bore needle
Who can perform a bone marrow aspiration or biopsy?
Physician, advanced practice nurse, or physician assistant
What is most common site for bone marrow aspiration/biopsy?
Iliac crest....May use sternum if more marrow is needed
What can pt expect to feel during bone marrow aspiration/ biopsy?
Heavy sensation of pressure and pushing, sometimes audible crunching sound can be heard. Painful pulling as the marrow is aspirated into needle. For biopsy, more pressure and discomfort is felt
Procedure for bone marrow aspiration
Skin site is cleaned, needle is inserted with twisting motion, marrow is aspirated into needle, needle is rapidly withdrawn, tissue supported at the site
Procedure for bone biopsy
Small incision is made in skin, biopsy needle inserted, pressure and several twisting motions are needed to ensure coring, external pressure applied to site until hemostasis is ensured...May use pressure dressing/sandbags to reduce bleeding
What is the number 1 nursing priority after bone marrow aspiration/biopsy?
Prevention of excessive bleeding
Follow up care for bone marrow aspiration/biopsy
Cover site with dressing, monitor for bleeding, infection, bruising. Avoid contact sports or potential trauma activities for 48 hours, aspirin free pain relievers, ice pack
Tissue responsible for blood formation (WBCs, RBCs, platelets)
Immature, unspecialized, undifferentiated cells produced in the bone marrow.
Blood stem cells
A growth factor made in the kidneys that is specific for the RBC
The three major types of plasma proteins
Albumin, globulins, fibrinogen
A main function of ALBUMIN
Maintains osmotic pressure of the blood, preventing plasma leakage to tissues
A main function of GLOBULINS
Transporting substances and functioning as antibodies
A main function of FIBRINOGEN
An inactive protein that is activated to form fibrin; important in blood clotting
The largest proportion of blood cells.
Red blood cells (erythrocytes)
The normal life span of a RBC
Name 2 items recycled items allocated from RBCs
This substance is essential in hemoglobin, allowing it to transport up to four molecules of oxygen (the heme part transports oxygen).
What is the function of the globin portion of hemoglobin?
Carries carbon dioxide
Selective growth of stem cells into mature erythrocytes.
What is the trigger for RBC production?
An increase in the need for tissue oxygenation
Stimulates increased RBC production in the bone marrow during hypoxia.
Growth factor erythropoietin
Substances needed to form hemoglobin and RBCs.
Iron, vitamin B12, folic acid, copper, pyridoxine, cobalt, nickel. A lack of any of these = anemia.
Perform actions important for protection through inflammation and immunity.
Stick to injured blood vessel walls and form platelet plugs that can stop the flow of blood from an injured site.
Bone marrow production of platelets is precisely controlled by this growth factor.
Percentage of platelets in circulation/ percentage of platelets stored in the spleen
Destroys old or imperfect RBCs, breaks down the hemoglobin released from these destroyed cells, stores platelets, and filters antigens.
Produces prothrombin and most of the blood clotting factors.
The multi-step process of controlled blood clotting.
Three sequential processes result in blood clotting.
Platelet aggregation, blood clotting cascade, fibrin clot formation
Substances that cause platelets to clump.
ADP, calcium, thromboxane A2, collagen.
Conditions directly in the blood itself that first activate platelets and then trigger the blood clotting cascade.
Outside of the blood that can activate platelets.
An inactive protein made in the liver, acted on by thrombin to aid in blood clot formation.
Fibrin (converted to fibrinogen)
Anti-clotting forces involve two types of actions.
1. activated clotting factors are limited
2. fibrinolysis (prevents over-enlargement of clot)
Protein C,, Protein S, antithrombin III
4 assessments for hematologic disorders
1. capillary refill
2. hair distribution
3. skin moisture
4. skin color
Anticoagulants do not break down existing clots. How do they work?
They interfere with one or more steps in the blood clotting cascade.
Drugs that selectively break down fibrin threads present in formed blood clots.
Fibrinolytic or thrombolytic drugs
The protein plasminogen activated to plasmin does what to fibrin?
Directly attacks and degrades it molecularly.
How does aspirin interfere with blood clotting?
a. prevents vitamin K synthesis
b. inhibits the activation of platelets
c. increases the rate of platelet destruction
d. prevents fibrin from assembling into long strands
b. inhibits production of substances that activate platelets such as thromboxane.
The single most common symptom of anemia.
Pinpoint hemorrhagic lesions in the skin
Blood in the urine appearing red or dark brownish gold
Is the normal adult spleen palpable?
Taking a drop of blood and spreading it over a slide.
Peripheral blood smear
Complete blood count: RBC, WBC, hematocrit, hemoglobin level
RBC in 1mm cubed of blood
WBC in 1mm cubed of blood
Hct % of RBCs in total blood volume
Determining bone marrow function: a reticulocyte is an immature RBC that still has its nucleus
reflects the number of platelets in ciruclation
Detects abnormal forms of hemoglobin (sickle cell disease)
Leukocyte alkaline phosphatase: enzyme produced by normal mature neutrophils; elevated levels during stress or infection
Direct test: detects antibodies against RBCs that may be attached to a persons RBCs
Indirect test: detects presence of circulating antiglobulins
Serum ferritin test
measures amount of free iron in the plasma
Protein that transports iron from the intestines to cell storage sites.
Test measured by taking a sample of blood and adding measured amounts of iron to it (total iron-binding capacity).
Prothrombin time: how long blood takes to clot (normal 11-12.5 seconds)
International normalized ration: divide the patient's PT by the established standard PT (normal 0.7-1.8)
Partial thromboplastin time: assesses the intrinsic clotting cascade and the action of factors II, V, VIII, IX, XI, and XII
Therapy monitored using PT levels
Therapy monitored using PTT or anti-factor Xa tests
unfractionated heparin (Calciparin)
Anti-factor Xa test
Measures amount of anti-activated factor X in blood affected by heparin: used mainly to monitor heparin levels
Platelet aggregation test
Mix patient's plasma with an agonist substance that should cause clumping (collagen, epinephrine, ADP, ristocetin).
Performed to evaluate the patient's hematologic status when other tests show persistent abnormal findings that indicate a possible problem in blood cell production or maturation. Reflects the degree and quality of bone marrow activity present.
Bone marrow aspiration and biopsy
BP > 180/120 must be lowered immediately to prevent damage to target organs
BP is very high but non evidence of immediate or progressive target organ damage
what are the 2 serum markers of myocardial damage
Troponin T and I,
Creatine kinase (CT)
What could be cause of bruit heard over an artery?
caused by things other than disease, examples are family history, over age 60, diet, physical inactivity, obesity, excessive alcohol intake, smoking
result of specific disease states and drugs, examples are kidney disease (number 1 cause), Cushing's disease, brain tumors, pregnancy, encephalitis
plaque in artery
Where is the major site of antibody production
What is given in case of heparin overdose?
What is given in case of cumadin or warfarin overdose?
total cholesterol level
less than 200 mg/dL
less than 150 mg/dL
greater than 40 mg/dL
LDL level for cardio pt's
less than 70 mg/dL
shows electrical activity of heart, detect dysrhythmias, and site and extent of MI...non-invasive and can be performed by nurse
shows information about structure and movement of heart. useful for assessing heart valves. Uses ultrasound, non-invasive
pharmacologic stress echocardiogram pt prep
NPO for 3-6 hours before test and careful monitoring of pt before and after test
venous duplex ultrasonography
use of ultrasound to assess flow of blood through veins of arms and legs
shows how heart responds to increased workload...can be done with treadmill or with medicines...resting EKG and then carefully monitored while exercising.
what should pt be instructed on before stress test?
have a light meal a few hours prior to test and may have to hold certain meds.
What should be in room during a stress test?
emergency equipment and a cardiologist
use of dye injected into arteries to evaluate blood flow in extremeties, mesentery, and brain...invasive and signed consent must be obtained
use of contrast dye to evaluate blood flow in heart, invasive and requires signed consent
Why is hypertension nicknamed the silent killer?
usually NO symptoms other than elevated blood pressure
What are some early symptoms of hypertension?
headaches, facial flushing, dizziness, fainting
What are some late and serious symptoms of hypertension related to organ damage?
retinal and other eye changes, renal damage, MI, cardiac hypertrophy, stroke
insufficient oxygen supply to meet requirements of myocardium
necrosis that occurs when severe ischemia is prolonged, irreversible damage to tissue
classic symptoms of MI
tightness, choking, or heavy sensation. pain may radiate to neck, jaw, shoulders, back, or arm (usually left), anxiety, dyspnea, SOB, dizziness, nausea, vomiting
atypical symptoms of MI (often seen in women)
indigestion, pain between shoulders, aching jaw, chocking sensation that comes with exertion, fatigue, sleep disturbance, dyspnea
the pain subsides with rest or NGC
characterized by increased frequency and severity and is not relieved by rest and NGC...call 911
What are the 1st line barriers to infections?
PHYSICAL BARRIERS-Skin, Mucous Membranes, Cilia, Sneeze/Cough reflex, WBC's phagocytosis
CHEMICAL BARRIERS- Enzymes in saliva and tears. HCL acid in GI tract
What are the characteristics of active immunity?
It can be natural because the body makes antibodies during an illness.
Or it can be artificial because of vaccines or immunizations to help the body build up antibodies (ex. MMR, small pox, polio).
It is long lasting.
This is the best immunity.
Requires boosters to maintain quick response.
What are the characteristics of passive immunity?
Can be natural when passed from mother to fetus or baby through breast milk.
Provides a short-term protection against specific antigens.
Can be artificial if antibodies were produced outside of body and given to pt. via mimmunization. (Used for snake bites, rabies, tetanus).
Common agents that cause Anaphylaxis shock
Antibiotics (Penicilin, cephalosporins, tetracycline, streptomycin etc.)
Adrenocorticotropic hormone, insulin, protamine, vasopressin.
Vaccines, lidocaine, procaine, muscle relaxants.
ACE inhibitors, ARBs, Chemotherapy agents, Monoclonal antibodies, Opiates
Peanuts, Shellfish, Eggs, legumes, Grains, Berries, Preservatives, Bananas.
Pollens, molds, latex,
Insects- bees, wasps, hornets, Fire ants, Snake venom
Common symptoms of Anaphylactic Reactions.
Initially- anxious: stress response.
Pruritus, Hives, Eyes and lips may swell.
Inflammatory response releases bradykinin which
causes- bronchiolar constriction- wheezes, Larynx swelling (hoarsness & stridor)- needs immediate intubation.
Hypotension- because of vasodilation and capillary permeability from histamine and serotonin (causes increase in mucous)
How to manage Anaphylactic Reactions
Intubation and ventilation
Epinephrine (can prevent vasoconstriction and bronchodilator)
Antihistamines (benedryl, H2 receptor blocker- ranitidine)
What is Histamine's function with allergies?
Histamine causes an inflammatory response by opening up capillaries to allow proteins and WBC to travel to a specific location to fight off any infection. Proteins draw in the WBCs to create a more general inflammatory reaction
What is the function of T-Cells?
They attack the antigen directly.
What is the function of B-Lymphocytes?
They create antibodies that can neutralize, eliminate or destroy a specific antigen/OR they become memory cells that are inactive until the same antigen shows up which stimulate antibody production for a more rapid response.
What is the function of Helper T-Cells?
Release cytokines, Simulate B-cell and cytotoxic T-cell activity.
Secrete lymphokines which increases WBC activity.
What is the function of Cytotoxic T-Cells?
Recognizes infected "self cells"
Destroys Parasites, viruses, protozoans, bacteria.
What is the function of Killer T-Cells?
Respond to "non-self" antigen without being sensitzed.
Used for cancer therapy.
Seek and Destroy- transplants/cancer/ unhealthy tissue.
Bind to surface of invading cell.
Destroys cell by changing inside of the cell.
It kicks ass!!!!
What is the function of Suppressor T-cells?
Has opposite effect of helper T-Cells.
prevents immune system from over reacting.
prevents the formation of antibodies that attach to 'self' proteins. If this doesn't work well then there is an auto-immune disease.
Produce lymphokines that inhibit most of the immune system cells.
Calls of immune response when threat ends.
What is a scratch test?
It is a test that shows which allergies a person is vulnerable to (rhinitis, asthma, urticaria ((hives)). It can show an immediate hypersensitivity reaction usually within 15-20 minutes. Wheal show up when a reaction is positive
What is an intradermal test?
It's a test that is used for suspected causing allergens which did not test positive on a scratch test. This test has an increased risk of an adverse reaction. Sera is injected intradermally and the pt is observed for erythema and wheal formation. Degree of allergy is estimated by size of response.
It is important to have emergency equipment in case of anaphylaxis.
What is the Oral food change test?
It is used for allergic rhinitis when the allergen is eaten. This is used to identify specific allergens if skin testing is not conculsive and if keeping a food diary has failed to determine the offending food items.
What is in vitro testing?
Used in pt's who have extensive dermatoses resulting in the inability of skin testing. It produces higher test sensitivity and specificity by using a matrix capsule containing antigen bound to a hydrophilic carrier to produce enhanced specific IgE binding with lower nonspecific IgE binding. Disadvantages are potential decrease in sensitivity, added cost, and lack of immediate and visible response.
What are the factors that affect Immunity?
Age- thymus shrinks (T and B cell production slows)
Nutrition- Protein calorie malnutrition (inadequate protein to make cells.
Pre-existing disease- dulls immune response (renal failure, diabetes, burns, etc. causes immunosuppression).
Disease Treatments- Medications (corticosteroids suppress immune function)
Virulence of the organism, Number of Organisms, Innate/species resistance
Which statement best exemplifies the client's protection from cancer provided by cell-mediated immunity (CMI) after exposure to asbestos?
A. Cytotoxic and cytolytic T-cells destroy cells that contain the major histocompatibility complex of a processed antigen.
B. Helper and inducer T-cells recognize self-cells versus non-self-cells and secrete lymphokines that can enhance the activity of white blood cells.
C. Suppressor T-cells prevent hypersensitivity when a client is exposed to non-self-cells or to proteins.
D. Balance elicits protection when helper or inducer T-cells outnumber suppressor T-cells by a ratio of 2:1.
Optimal function of CMI requires a balance between helper and inducer T-cells and suppressor T-cells. This balance occurs when helper and inducer T-cells outnumber suppressor T-cells by a ratio of 2:1.
What are Type 1 Hypersensitivity (allergic) reactions?
acute inflammation in response to a normally harmless antigen
Pollen, Animal dander, Food, Drugs, Anaphylaxis
What are Type 2 Hypersensitivity (allergic) reactions?
ABO blood compatibility, Rh incompatibility, Hemolytic anemia's
What are Type 3 Hypersensitivity (allergic) reactions?
Immune complexes with antigens attached to the lining of Blood vessels. Autoimmun disorders (Rheumatoid arthritis, Systemic Lupus Erythematosis (SLE).
What are Type 4 Hypersensitivity (allergic) reactions?
Delayed reactions- occurs up to 48 hours later.
Most contact dermatitis (Poison Ivy, PPD, T-Cells sensitized by TB).
What are Type 5 Hypersensitivity (allergic) reactions?
Fail to recognize 'self' cells.
Immune system is 'on' for specific cell types (Graves Disease- TSH receptors are the target.
Type 1 Diabetes Mellitus)
What is the normal range for blood pH?
What is the normal range for PaCO2?
What is the normal range for PaO2?