Lab Values / Clinical Chem Sem 1

Question 1

What are the normal values of K+ ?

Answer 1

3.5 to 5.0 mmol/L

Question 2

What are the normal values for Na+ ?

Answer 2

136 to 145 mmol/L

Question 3

What are the normal values of Cl- ?

Answer 3

98 to 106 mmol/L

Question 4

What are the normal values of iCa++ ?

Answer 4

1.1 to 1.3 mmol/L

Question 5

Arterial pH normal values ?

Answer 5

7.35 to 7.45

Question 6

Arterial PaCO2 normal values ?

Answer 6

35 to 45 mmHg

Question 7

Normal arterial values for HCO3- ?

Answer 7

21 to 28 mmol/L

Question 8

Normal values of PaO2 ?

Answer 8

80 to 100 mmHg

Question 9

Normal Rage for Base Excess ?

Answer 9

0+ to -2 mmol/L

Question 10

What is the normal values for Creatinine ?

Answer 10

Male : 25-90 U/L

Female : 10 - 70 U/L

Question 11

What are the critical values for BE ? And what do they mean ?

Answer 11

-3 or +3
-3 or more negative = lack of base (HCO3) = metabolic acidosis
+3 or more positive = excess of base (HCO3) = metabolic alkalosis

Question 12

What is the normal range of Anion Gap ?

Answer 12

3 - 11

Question 13

What value is considered an elevated Anion Gap ? What does it mean ? What is it typically caused by ?

Answer 13

HIGH > 12

Indicative of Metabolic Acidosis

Mostly due to increase in Organic Acids (Lactic , Keto, Formic, Oxalic)

Question 14

How do you calculate Anion Gap ?

Answer 14

[Na+] + [K+] minus [Cl-] + [HCO3]

Often you drop the K in the equation, minimal impact ?

Question 15

Explain Hyperchloremic Acidosis .

Answer 15

HYPERChloremic Metabolic Acidosis is a Normal Anion Gap (3-11) Metabolic Acidosis due to HCO3 loss.

Caused by extra loss of HCO3, ie diarrhea, renal……the body retains more Cl- to balance charges

(Sometime it’s due to addition of Cl- (fluids), which dilutes the HCO3 and can precipitate loss of HCO3 renally)

(**connected in concept to Base Excess, a -ve BE (-3 or lower) is indicative of low HCO3 and identifies metabolic acidosis)

Question 16

14 y/o M, unresponsive at home. Presents hypotensive, tachycardic and tachypneic with GCS 10. Labs as follows:

Na 127 K 5.2 Cl 87 BUN 32 CREAT 150 BG 32

pH 6.92 , pCO2 9 , pO2 venous =55, HCO3 - 2, Lactate 3.4

Based on above, what is your workable Dx and Tx concerns and approach?

Answer 16

This is a classic case of Diabetic Keto Acidosis.

Findings: - Acidosis (pH very low, pCO2 also very low, and HCO3 also very low) - - - EXTREME ACIDOSIS (with not much room
to fix itself) - - - how do we know if it is RESP / MET - - - which component is more acidic than normal - - HC03, therefore
EXTREME PARTIALLY COMPENSATED METABOLIC ACIDOSIS - low pH, low HCO3 and low CO2 (compensation, but pH still low, so partial)
- Sugar = 32 - very high
- decreased LOA and elevated RR fit clinical picture
- K high (slight 5.2 > 5.0, critical > 6.5) - - - (K shifts inside cell with insulin treatment, so if giving insulin, might need to add K)
- Na low (< 136) secondary to polyuria

            - ANION GAP = 127 + 5.2  minus 87 + 2 = 43.2  (way higher than normal 3-11) - - -indicates a lot of organic acids
            - aside from Ketoacids, our lactate shows extra Lactic Acid too! >2.2 normal sitting at 3.4
            - does he also have an infection that triggered all this ? fever ? - - - he was hypotensive and tachycardic.......so  Sepsis as well

            - RSI / ETT / VENT would likely decrease his TV (tube diameter) - - - - try NOT to INTUBATE these patients, could kill them by decreasing
              one of their compensatory mechanism

            - Tx - HCO3, Insulin, K, Pressors/Fluid

Question 17

76 M, found decr LOA at home by neighbors. Presents tachypneic and GCS 11. Labs as follows:

NA 135 , K 7.3 , Cl 104 , iCa 0.87 , Creat - 2076

pH 6.92 , pCO2 16 , pO2 102 , HCO3- 3, Lactate 1.2

What is your working Dx, Tx considerations and approach ?

Answer 17

EXTREME METABOLIC ACIDOSIS, partially compensated - - very low pH, very low HCO3, very low pCO2 (CO2 compensated but still pH low)

• CREAT (2076) is HUGE, so ACIDOSIS SECONDARY TO HCO3 LOSS at KIDNEY - - -KIDNEY FAILURE
• HYPERKALEMIA (7.3), crit is > 6.5 - - - - anticipate ECG Changes, Peaked T, flattening P
• iCa is low (0.87 )…normal is 1.1-1.3

Treatment : ISOTONIC HCO3 (3 amps in 1 L bag, run 50 mEq/hr)
Just pushing quick AMPS, might make acidosis worse : HCO3 + H - - - H2CO3 - - - > H20 + CO2 by raising CO2
Calcium Gluconate ? (wasn’t mentioned in Lab, but iCa low, and Hyperkalemic - – seems reasonable

Question 18

37 F, presents to ED with distributive shock and intermittent seizure. Pt appears jaundice and has a distended abdo. LAB as follows:

Na 122 , K 1.9 , Cl 101, BG 2.3 , ALT 1256 , AST 2654

pH 7.13 , pCO2 19, HCO3 11, Lactate 14

What is your working Dx, Tx concerns and approach ?

Answer 18

EXTREME METABOLIC ACIDOSIS, partially compensated. pH Low, HCO3 LOW, pCO2 LOW (compensation)

Liver Enzymes, Jaundice and Distended Abdo suggest Liver Failure.

Neuro, secondary to Liver issues suggest Hepatic Encephalopathy. However, Tylenol OD can present similarly.

No quick fix to these labs, all need slow infusions. Can fix sugar, in case it’s cause of seizure
Liver Failure often have either HIGH or LOW Coags (not shown here)

Will want to measure ETOH and Tylenol Levels. IHx important to discover exact cause.
If Tyl OD - can use MUCOMIST