electrolytes acid base renal failure

Question 1

pCO2 compensation acute metabolic acidosis

Answer 1

pCO2 = HCO3 x 1.5 + 8

Question 2

pCO2 compensation acute metabolic alkalosis

Answer 2

pCO2 = HCO3 x 0.9 + 15

Question 3

Contrast induced nephropathy

Answer 3

24-48h later; Urine Na < 1; non-oliguric, ATN sediment

Question 4

Effect of hypoalbuminemia on AG

Answer 4

AG falls 2.5 meq for every 1 gm of albumin decrease

Question 5

Urine anion gap

Answer 5

-10 to +10; negative in metabolic acidosis due to NH4 secreton. Positive is RTA

Question 6

Anion Gap GOLDMARK

Answer 6

Glycols (ethylene and propylene), Oxoproline, Lactate L, Lactate D, Methanol, ASA, Renal failure, Ketoacidosis

Question 7

Lactic acidosis types

Answer 7

A-tissue hypoxia (e.g., shock)
B-Increased production, decreased utilization:
Drugs and Toxins: ASA, Ethanols, propylene glycol (medication dilutant cocaine, linezolid, b-agonists, linezolid
Malignancy, diabetes, infection, inborn errors of metabolism
Type D-jejunal bypass, short gut, DKA, propylene glycol

Question 8

5-oxoproline (pyroglutamic acid); cyclized glutamine

Answer 8

Typical profile: Women»men • Malnourished • Chronic paracetamol (acetaminophen) use decreases glutathione stores • Kidney and/or liver dysfunction; inborn errors of metabolism

Question 9

Hyponatremia

Answer 9

MDMA ecstacy stimulates ADH, marathon runners, water ingestions, post op SIADH; thiazides; edematous states (CHF,cirrhosis)

Question 10

SIADH criteria-inappropriately hold water

Answer 10

Nl vol, Low serum Osm, high urine osm, high urine Na

Question 11

Cerebral salt wasting

Answer 11

SIADH criteria, plus volume depleted: brain injury, SAH

Question 12

Vasopressin antagnoist

Answer 12

Tolvaptin (po), Conivaptin (iv) Rx in SIADH, CHF

Question 13

Sodium correction rate

Answer 13

Sodium level correction < 8 mmol/L in 24 hours or <18 mmol/L in 48 hours. Faster increases risk of osmotic demyelination syndrome (locked in, quadriparesis)

Question 14

Diabetes insipidus

Answer 14

Polyuria: Central (hypopit, brain inj) or Nephrogenic (vasopressin resistant)

Question 15

Free water calculation in hypernatremia

Answer 15

Water Deficit=Total Body Water x (Serum Na-Target Na+)/Target Na+
(TBW=lean wt x 0.5 men, 0.4 women)

Question 16

SIADH drugs

Answer 16

-NSAIDS
-MDMA (Ecstasy)
-Chemotherapy: iv cyclophosphamide, Carbamazepine, Vincristine or vinblastine
-Antipsychotics: Thiothixene, phenothiazines, Haloperidol,
tricyclic antidepressants
-Antidepressants: serotonin-reuptake inhibitors, MAO inhibitors
-Bromocriptine
-Clofibrate
-General anesthesia
-Narcotics, opiate derivatives
-Exogenous ADH: vasopressin, desmopressin, oxytoxin

Question 17

thyrotoxicosis periodic paralysis

Answer 17

Male, activated Na/K ATPase casues profound hypkalemia, threat thyrotoxic first, caution with hyperK rebound

Question 18

hypermagnesia

Answer 18

Bradycardia, Weakness, treat with calcium. Hx drinking epson salts

Question 19

FeNa=

Answer 19

FeNa= [Pcr x UNa/ Ucr xPNa] x 100

Question 20

Hypocalcemia

Answer 20

Weakness, tetany, treat with caclium infusion

Question 21

Serum Osm =

Answer 21

Sosm= 2Na + BUN/2.8 + Glu/18 +EtOH/3.7

Question 22

Water replacement calculation

Answer 22

Water = TBW (kg) x Na observed-Na goal/Na goal

Male 0.6 x kg; Femal 0.5 x kg

Question 23

treatment of hypercalcemia

Answer 23

Saline for volume
Calcitonin (short term)
Bisphosphonantes (long term) not in renal failure

Question 24

Succinylcholine and hyperkalemia

Answer 24

Contraindicated in diseases with increased acetylcholine receptors:
• Most neuromuscular diseases: Amyotrophic lateral sclerosis, multiple sclerosis, Hemiparesis, spinal cord injury, Acute inflammatory demyelinating polyneuropathy, Inherited myopathies
• Can be used in: • Myasthenia gravis (receptors blocked)

Question 25

Rare causes of hypokalemia

Answer 25

• Glue/paint sniffing (toluene) metabolized to hippurate, that is excreted as Na and K salts
• Barium ingestion (deplitory) blocks K movement out of cells
• b agonist (Clenbuterol-banned performance enhancer or heroin adulterant)

Question 26

bladder pressure/compartment syndrome

Answer 26

IAP> or equal to 12. Abd compartment syndrome (ACS)>equal to 20 assoc with new organ dysfunction

Question 27

Drug dosing during RRT determinants

Answer 27

1. primarily renal cleared, 2. Low MW (<1L), 4. not high protein binding

Question 28

type of RRT in AKI

Answer 28

CRRT-most successful negative fluid balance
No survival benefit any method
CRRT-better preserved cerebral perf if ICP
CRRT-greater mortality than IHD
CRRT-greater HD independence