Blood Chemistry Testing Flashcards
Purpose of testing blood gasses
Evaluate fxn of:
- Lungs
- Kidney
- Blood
What are the arterial blood gases? (7)
pH PaCO2 PaO2 SaO2 HCO3 O2CT Total C02
pH
pH = [H+] in blood Negative log (10x as much b/w levels) Tight range for blood = 7.35-7.45
PaC02
partial pressure of C02
Low = NORMAL –> 35-45mm Hg
High = poor blood ventilation
Pa02
partial pressure of 02
HIGH in arterial (oxygenated) blood = 80-100mm Hg
Ability of lung to oxygenate blood
Sa02
saturation level of blood
% of carrying capacity of blood if all hemoglobin was saturated
94-100%
HCO3
crucial for maintenance of blood pH = kidneys job to control concentration
22-26 mEq/L
O2CT
Actual amount of 02 in blood
15-23%
Low Pa02 with 02CT, and
Sa02 with high PaC02
Not getting 02 into lungs
muscle weakness, airway obstruction, resp center obstruction
DECREASE in: Pa02, 02CT, Sa02
Normal PaC02
Insufficient oxygenation of the blood
pneumothorax, septal defect, interstitial fibrosis
LOW 02CT
Normal: Pa02, Sa02, PaC02
Severe anemia
blood cant carry 02 or decreased blood volume (ie: bleeding)
Total Carbon Dioxide
end of metabolism: CO2 flows out of RBC and dissolves in plasma as carbonic acid
measures all forms of C02 in plasma (most = HCO3)
Normal: 22-26 mEq/L
Test = acid base balancing ability
What are some electrolytes? (7)
Na K Mg PO3 (phosphate) Ca Cl Anion Gap
Na = SODIUM
extracellular cation that maintains osmotic P
Controls body fluid level, membrane depolarization, acid base balance, regulates Cl and K
NORMAL: 135-145 mEq/L
[Na} and water
decrease = more water lost increase = more water absorbed
Hypernatremia
too much Na
- Dehydration
- Water loss exceeding Na loss: (Diabetes Insip, Kidney failure, vomit/diarrhea)
- Increase retention: primary ALD, increased intake
Hyponatremia
too little Na
- Inadequate intake (rare)
- Excessive Na loss: sweating, vomit/diarrhea, adrenal insuf, burns, chronic kidney disease)
K = POTASSIUM
intracellular cation
repolarizes membranes
Disturbance = altered cardiac rhythms, neural impulse transmission, muscle contraction
NORMAL = 3.5-5 mEq/L (most IN the cells)
Hyperkalemia
too much K
- Diet
- Intra to extra cellular shift
- renal failure
- MI
- insulin def / ketoacidosis
Hypokalemia
too little K
- Vomit/Diarrhea
- Diuretic use
- too much ALD produced
- GI / renal issue
- insulin injection w/o supplementation
Magnesium Mg
Crucial for enzymatic activation for DNA synthesis (nucleic acids + proteins)
Co-transports K & Na; Influences PTH and Ca = Most in BONE
NORMAL = 1.3-2.1 mg/dl
HIGH = renal failure...addisons disease LOW = alcoholism, HPT, diuretics, ALDism, pancreaitis
P03 = PHOSPHATE
store / utilize ATP
Ca regulator, Bone formation, RBC production
NORMAL = 2.7-4.5 mg/dl
Hypophosphatemia
too little
Malnutrition, HPT, will suppress child growth
Hyperphosphatemia
too much
Skeletal disease (acromegaly via tumor in pituitary)
Healing fx
hypoparathyroidism
Ca = CALCIUM
1% BODY TOTAL IN BLOOD
40% ionized, 50% bound
— ionized = 8:1g ratio w/ serum albumin
NORMAL:
- total = 8.2-10.2 mg/dl
- ionized = 4.65-5.28mg/dl
Hypercalcemia
too much
HPT, Pagets, MM, Mets, Fx
Hypocalcemia
too little
Hypoparathyroidism, Malabsorption, excessive loss (Cushings)
Cl = CHLORIDE
w/ Na to maintain osmotic P
regulates blood vol/P
Absorbed in intestines, Kidneys excrete
NORMAL = 100-108 mEq/L
— inversely related to HC03
Hyperchloremia
too much
Severe dehydration (dehydration), hyperventilation
Hypochloremia
too little
Assoc w/ low Na + K levels
Vomiting, addisons
Anion Gap
- reflects anion cation balance
- tests: Na + Cl + HCO3
- serum should be neutral
Na = 90% cation
Cl + PO3 = 85% anion
NORMAL = 8-14 mEq/L
Normal Gap Acidosis
Loss of HC03
Renal absorption of Na & Cl increases
Gap remains constant but HCO3 buffer is lost
High Gap Acidosis
Measured by increase in anions
Due to accumulation of metabolic acids (renal failure, ketoacidosis [starvation, DM, alcohol]
