BMP

Question 1

Anion Gap

Answer 1

• used to determine the cause of Metabolic Acidosis
• normal range 8-16
• equation:
  • ANION GAP = ([Na⁺] + [K⁺]) - ([HCO₃^-] + [Cl^-])
• if anion gap is HIGH, suggests that an acid is “soaking” up HCO₃^-

Question 2

Causes of an anion gap metabolic Acidosis

Answer 2

CAT MUDPILES

• Carbon Monoxide
• Aminoglycosides
• Theophylline
• Methanol
• Uremia
• DKA
• Paraldehyde
• Iron, Isoniazid
• Lactic Acidosis
• Ethanol, Ethylene Glycol
• Salicylate/ASA/Aspirin

Question 3

What is in a BMP?

Answer 3

• calcium
• Carbon dioxide
• chloride
• creatinine
• glucose
• potassium
• urea nitrogen (BUN)
• sodium

Question 4

When do you order a BMP?

Answer 4

• screening for diabetes and renal disease
• monitoring of kidney function in pts on meds
• to explore cause of sxs the pt is c/o
• in acute illness or trauma to help evaluate the state of the patient
  *

Question 5

Fish Bone

Answer 5

1. Na⁺
2. K⁺
3. Cl^-
4. CO₂^-
5. BUN
6. Cr
7. Glucose

Question 6

Sodium

Answer 6

Main Cation of the extracellular space

normal range 135-145 mEq/L

**Critical Values : <120 or >160

sodium in the blood = balance of dietary sodium and renal excretion

hyperglycemia can lead to low sodium → for every 60mg/100ml > normal - sodium decreased by 1mEq

→ glucose pulls water into ECF and dilutes the sodium

Question 7

Potassium

Answer 7

Normal Range: 3.3-5 mmol/L

Critical Value <3 or >6.1

Major intracellular cation

• intracellular concentration of K⁺ = 150 mEq/L
• potassium is excreted in the kidneys
• small variations = effect HR and cardiac contractility
• normally supplied by the diet
• important role in protein synthesis, acid base balance, sodium reabsorption
• Collection Errors:
  
  • opening and closing fist with tourniquet will increase K
  • hemolysis of blood in collection or processing can increase K

Question 8

Chloride

Answer 8

Major Extracellular Anion

normal 95-110mmol?L

Critical values <80 or >115

• maintain electrical neutrality mostly as a salt NaCl
• effects water balance
• acts as buffer to assist in acid base balance
• shifts in chloride are usually related to sodium or bicarb

Question 9

Carbon Dioxide

Answer 9

aka Bicarbonate HCO₃^-

measure of CO₂ in the blood

normal: 24-32mmol/L

critical <10 or >40

• assists in evaluating pH status of pt
• major role in acid base balance
• negative charge: important for electrical neutrality
• venous blood sample NOT as accurate arterial blood gas in finding the CO₂ levels

Question 10

Arterial Blood Gas

Answer 10

collected from arteries NOT veins

special processing → immediately placed on ice and brought to lab

• Normal Values:
  
  • pH = 7.35-7.45
  • PaO₂: >90mmHg
  • PaCO₂: 35-45mmHg
  • HCO₃^-: 18

Question 11

Arterial Blood Gas

Answer 11

collected from arteries NOT veins

special processing → immediately placed on ice and brought to lab

• Normal Values:
  
  • pH = 7.35-7.45
  • PaO₂: >90mmHg
  • PaCO₂: 35-45mmHg
  • HCO₃^-: 24-32 mEq/L

Question 12

BUN

Answer 12

Blood urea nitrogen

indirect rough measurement of renal function and GFR

must have normal liver fx to be a valid test

• Normal Range: 8-22mg/dL
  
  • critical >100 (no critical low)
• BUN = formed in the liver at the end of protein metabolism then excreted through the kidneys
• increased BUN = azotemia
• BUN may be low in severe liver disease (decreased synthesis of BUN)
• non-renal causes:
  
  • pre-renal azotemia: result of pathological condition that causes BUN to rise before kidneys
  • post-renal azotemia: BUN accumulates in kidneys due to ureteral or urethral obstruction

Question 13

Creatinine

Answer 13

• Average Adult Range = 0.44-1.27mg/dL
  
  • critical value >4
• Measurement of renal function
• lean body mass effects level of creatinine
• * in general, doubling of creatinine = >50% reduction of GFR ***
• used as estimate of GFR (eGFR)

normal is variable and is dependent on age, gender, and muscle mass → should trend these!

Question 14

Creatinine Clearance Test

Answer 14

requires urine collection for 24 hours and a serum creatinine level for 24 hours

expensive and takes a lot of time → more efficient and reasonable for everyday practice to use eGFR

Question 15

Glucose

Answer 15

• Normal Range for Fasting Adult: 70-99
  
  • critical values:
    
    • male: <50 or >450
    • female: <40 or >450
    • infant: <40
    • newborn: <30 or >300

Question 16

Calcium

Answer 16

• Normal Calcium Range: 8.6-10.5 mg/dl (total Ca²⁺ in the blood)
  
  • critical <6 or >13
• necessary for metabolic pathways
  
  • muscle contractility, cardiac function, and neural transmission
• serum Ca²⁺ → reflection of parathyroid hormone (PTH) and parathyroid function
• levels must be elevated on 3 different times to be considered hypercalcemia

Question 17

BUN:Creatinine Ratio

Answer 17

Normal: 20:1

• Low:
  
  • acute tubular necrosis
  • low protein intake
  • starvation
  • severe liver disease
• High:
  
  • pre-renal uremia
  • high protein intake
  • after GI bleeding
• High with raised creatinine:
  
  • post-renal obstruction
  • pre-renal uremia with renal disease