acid-base

Question 1

Normal pH value

Answer 1

7.35-7.45

Question 2

normal CO2 level

Answer 2

35-45

Question 3

normal pO2 level

Answer 3

80-100

Question 4

normal HCO3 level

Answer 4

22-26

Question 5

What is ketoacidosis

Answer 5

high anion gap metabolic acidosis due to excessive blood concentration of ketone bodies (ketoanionis)

Question 6

The basic underlying mechanism of diabetic ketoacidosis

Answer 6

• lack of insulin in the body -> elevation of glucagon -> release of glucose by the liver (normally suppressed by insulin) from glycogen via glycogenolysis and gluconeogenesis
• high glucose level in urine, loss of H2O, K+ and Na2+ = osmotic diurses -> polyuria, dehydration, polydipsia
• absence of insulin -> release of FA (lipolysis) thich liver converts into acetyl CoA (beta oxidation)
• acetyl CoA is metabolised into ketone bodies under severe states of energy deficiency = ketogenesis
• final producats are aceto-acetate and beta hydroxybutyrate
• ketone bodies = new energy source, but they make blood acidic (metabolic acidosis)
• alkaline reserves (K and Na) are lost so further acidosis
• buffering with bicarbonate system, but not enough so hyperventilation occurs (Kussmaul respiration in extreme cases)

Question 7

List clinical features of DKA (symptoms) (3)

Answer 7

1. classic symptoms of hyperglycemia: short period of time: polyuria, polydipisa, wt loss, thirst
2. other symptoms: general weakness, malaise and lethargy
   - nausea, vomiting and abdominal pain
   perspiration
   distrubed consciousness and confusion
   symptoms underlying infections or other condition: fever, abd pain, dysuria, chest pain

Question 8

Precipitating factors for ketoacidosis (9)

Answer 8

1. stress
2. infections: UTI, CHest, fungal
3. stroke,
4. pregnancy
5. steroids
6. trauma
7. pancreatitis
8. surgery
9. hyperthyroidism

Question 9

Physical signs of DKA

Answer 9

a. general signs: ill appereance and disturbed conscioussness
b. dehydration : dry hot skin, loss of turgor, dry tongue, sunken eyes, dark circles under the eyes
c. vital signes: tachy, hypotension, tychpnea
d. specific signs: ketotic breath (fruity breath similar to nail polish remover), acidotic breath (Kussmauls respiration deep and rapid), abdominal tenderness

Question 10

What happens to sodium in DKA?

Answer 10

sodium is usually low because hyperglycemia leads to loss of water and sodium with it

Question 11

what happens to potassium in DKA?

Answer 11

Serum K: Usually high (hyperkalemia) secondary to:
1. -Shift of K from intracellular to extracellular compartment due to:
Insulin deficiency and hyperglycemia.
Extracellular hyperosmolarity.
Acidosis.
↑ Catabolism and breakdown of cellular protein.
2.-Impaired cellular uptake of K.

Question 12

List complications of DKA (4)

Answer 12

1. complications of associated illnesses
2. adult respiratory distress syndrome
3. thromboembolism
4. complications of treatment

Question 13

List complications of DKA treatment (4)

Answer 13

1. hypokalemia (can lead to cardiac arrythmias, cardiac arrest, respiratory muscle weakness)
2. hypoglycemia
3. overhydration and acute pulmonary edema (treating children with dKA, adulst with compromised renal or cardiac function, elderly with incipient CHF)
4. neurlogical complications (cerebral edema, only in chidlren with DKA, increases mortality, related to severity duration and rapid correction of DKA)

Question 14

Order of DKA evaluation (10)

Answer 14

1. ABC
2. cardiac monitoring
3. physical examination
4. IV access: 2 large bore lines (16-18G)
5. CVP may be needed
6. blood sugar
7. catheter
8. urinalasys for ketones
9. ECG
10. Infection screen (BC, blood and urine cultrue, CRP, chest X ray)

Question 15

Main 3 things to resolve in DKA

Answer 15

1. fluid replacement
2. insulin
3. potassium

Question 16

Describe how do you manage fluid replacement

Answer 16

0.9 saline is the replacement of choice
typical fluid loss is 100ml/kg, so for average man 70kg=7L

u prva 4h, daj 500mL/h
u narednih 8h, daj 500mL svaka 2h
narednih 8h, daj 1000mL

When blood glucose <15mmol/L add 5 % glucose to rehydration fluid

this regimen may not be appropriate for all: reassess frequently, especially if young, elderly, pregnant, or comorbidites

bicarbonate may increase risk of cerebral edema and is not recommended

Question 17

Insulin management DKA

Answer 17

add 50 units human soluble insulin to 50 mL 0.9%saline

infuse continuously at 0.1 unit/kg/h

continue patient’s regular long-acting insulin at usual doses and times

aim for a fall in iblood ketones of 0.5mmol/L/h, or a rise in venous bicarbonate of 3mmol/L/h with a fall of glucose of 3mmol/L/h

if not achieving this, increase insulin infusion by 1unit/h until target rates achieved

Question 18

How would you manage potassium in DKA

Answer 18

Tpical deficit is 3-5mmol/kg, plasma K falls with treatment as K enters cells

dont add K to the first bag of IV

Then add potassium to the most recent VBG result

When < 3.5 mmol/L, give 20 mmol/hr
*When plasma potassium is 3.5-5.0 mmol/L, give 10 mmol/hr

Question 18

How would you manage potassium in DKA

Answer 18

Tpical deficit is 3-5mmol/kg, plasma K falls with treatment as K enters cells

dont add K to the first bag of IV

Then add potassium to the most recent VBG result

When < 3.5 mmol/L, give 20 mmol/hr
*When plasma potassium is 3.5-5.0 mmol/L, give 10 mmol/hr