Med Surg Exam 2 Flashcards
Normal pH
7.35-7.45
Acidosis
<7.35
Alkalosis
> 7.45
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?
ammonia
phosphates
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”
retains bicarb
How do the kidneys compensate in alkalosis?
saves H+ (K+ goes) “i’m staying, get outta here”
excretes bicarb
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?
hyperventilation
Hypoxia (trying to get O2)
fever-tachypnea
What are signs of respiratory alkalosis?
lightheaded, dizzy
What are causes of metabolic acidosis?
diabetic ketoacidosis, end stage renal disease
lactic acidosis & starvation
What are signs of metabolic acidosis?
Nausea vomiting disorientation kussmaul respirations muscle twitching changes in LOC
What are causes of metabolic alkalosis?
overuse of antacids
vomiting
GI suction
hypokalemia
What are signs of metabolic alkalosis?
tingling numbness 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?
3 months
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?
Yes
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)
Bone marrow
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
erythropoietin
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
120 days
Name 2 items recycled items allocated from RBCs
Iron, hemoglobin
This substance is essential in hemoglobin, allowing it to transport up to four molecules of oxygen (the heme part transports oxygen).
Iron
What is the function of the globin portion of hemoglobin?
Carries carbon dioxide
Selective growth of stem cells into mature erythrocytes.
Erythropoiesis
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.
Leukocytes
Stick to injured blood vessel walls and form platelet plugs that can stop the flow of blood from an injured site.
Platelets