electrolytes acid base renal failure Flashcards
pCO2 compensation acute metabolic acidosis
pCO2 = HCO3 x 1.5 + 8
pCO2 compensation acute metabolic alkalosis
pCO2 = HCO3 x 0.9 + 15
Contrast induced nephropathy
24-48h later; Urine Na < 1; non-oliguric, ATN sediment
Effect of hypoalbuminemia on AG
AG falls 2.5 meq for every 1 gm of albumin decrease
Urine anion gap
-10 to +10; negative in metabolic acidosis due to NH4 secreton. Positive is RTA
Anion Gap GOLDMARK
Glycols (ethylene and propylene), Oxoproline, Lactate L, Lactate D, Methanol, ASA, Renal failure, Ketoacidosis
Lactic acidosis types
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
5-oxoproline (pyroglutamic acid); cyclized glutamine
Typical profile: Women»men • Malnourished • Chronic paracetamol (acetaminophen) use decreases glutathione stores • Kidney and/or liver dysfunction; inborn errors of metabolism
Hyponatremia
MDMA ecstacy stimulates ADH, marathon runners, water ingestions, post op SIADH; thiazides; edematous states (CHF,cirrhosis)
SIADH criteria-inappropriately hold water
Nl vol, Low serum Osm, high urine osm, high urine Na
Cerebral salt wasting
SIADH criteria, plus volume depleted: brain injury, SAH
Vasopressin antagnoist
Tolvaptin (po), Conivaptin (iv) Rx in SIADH, CHF
Sodium correction rate
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)
Diabetes insipidus
Polyuria: Central (hypopit, brain inj) or Nephrogenic (vasopressin resistant)
Free water calculation in hypernatremia
Water Deficit=Total Body Water x (Serum Na-Target Na+)/Target Na+
(TBW=lean wt x 0.5 men, 0.4 women)
SIADH drugs
-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
thyrotoxicosis periodic paralysis
Male, activated Na/K ATPase casues profound hypkalemia, threat thyrotoxic first, caution with hyperK rebound
hypermagnesia
Bradycardia, Weakness, treat with calcium. Hx drinking epson salts
FeNa=
FeNa= [Pcr x UNa/ Ucr xPNa] x 100
Hypocalcemia
Weakness, tetany, treat with caclium infusion
Serum Osm =
Sosm= 2Na + BUN/2.8 + Glu/18 +EtOH/3.7
Water replacement calculation
Water = TBW (kg) x Na observed-Na goal/Na goal
Male 0.6 x kg; Femal 0.5 x kg
treatment of hypercalcemia
Saline for volume
Calcitonin (short term)
Bisphosphonantes (long term) not in renal failure
Succinylcholine and hyperkalemia
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)
Rare causes of hypokalemia
- 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)
bladder pressure/compartment syndrome
IAP> or equal to 12. Abd compartment syndrome (ACS)>equal to 20 assoc with new organ dysfunction
Drug dosing during RRT determinants
- primarily renal cleared, 2. Low MW (<1L), 4. not high protein binding
type of RRT in AKI
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
