Transcript Electrolytes_Resident_Lecture
Electrolyte management in the PICU
2012
Goals
• To discuss the pathophysiology of electrolyte disturbances • To review the acute management of electrolyte disturbances • To discuss 2 cases with audience participation
Case 1
• 13 yo male admitted to the PICU after crashing into a wall during a motorcross competition. • He is intubated with a current GCS of 6T and is receiving aggressive management for increased ICP’s. • Review head CT on next slide • On hospital day 2, his urine output increases to 10ml/kg/h.
Case 1
• HR 120 T 36 BP 110/62 98% on 50% FiO2 • CVP 2 • I/0 balance = -600 • What could be happening?
• What labs would you send?
Case 1
• Differential diagnosis: • Post resuscitation diuresis • Polyuric ATN • Hyperglycemia/post-mannitol • Central Diabetes Insipidus • Cerebral salt wasting • Labs to send: • UA with spec grav • Urine osmolality, Urine sodium • Serum osmolality, Serum sodium • Basic metabolic panel
Case 1
• Na 158 K 4 BUN 25 Creat 0.7 Gluc 140 • Sosm 340 Uosm= 121 • UA sg 1.001 glucose negative • Una= 10 • Sum it up: • Hypernatremia + Hypovolemia + Increased DILUTE urine output
Case 1
• What other information would you want to know?
• Types/amounts of IVF received over the last 24 hours • Whether mannitol or diuretics were given • What is the most likely diagnosis?
• DI • How would you manage this patient?
• Resuscitate with NS if needed • Fluid replacement with 1/2 or 1/4 NS • Vasopressin infusion titrated to UOP 3-4ml/kg/h
Case 1
• Your management strategy is effective and the patient’s UOP slows to 3 4ml/kg/hr. • On hospital day 4, previous therapies to adjust UOP have been discontinued.
• The UOP continues to slow to <1ml/kg/hr.
Case 1
• T 36 HR 89 BP 118/72 CVP 12 • Na= 129, Serum Osm 277 BUN 10 • UA 1.025 Uosm=550 Una= 75 • Sum it up: • Hyponatremia + euvolemia + low UOP that is CONCENTRATED • What diagnoses would you consider?
• SIADH, hythyroidism, glucocorticoid deficiency, psychogenic polydipsia, iatrogenic free water exces • How would you treat this?
• Fluid restriction 30-50% maintenance • Avoid free water excess (use isotonic solutions)
Case 1
• On HD #6, despite fluid restriction and avoidance of excess free water, the sodium continues to trend down. UOP is 3-4ml/kg/hr.
• Serum Na= 125 • Repeat UA = sg 1.015 Una= 250 • Sum it up: • Hyponatremia + euvolemia + high normal UOP that has A LOT of SODIUM • What could be happening? • Cerebral salt wasting
The body keeps your Posm between 280 290 mOsm/L….
thirst vasopressin Plasma osmolality Salt intake
vasopressin Renin-angiotensin thirst Blood pressure/effective ECF Atrial naturietic factor Symphathetic nervous system Salt intake
Hyponatremia
Hyponatremia: Clinical signs and symptoms
• Nausea/vomiting • Lethargy • Headache • Confusion • Seizures • Non-cardiogenic pulmonary edema • These are mostly due to CNS dysfunction and cerebral edema!
Hyponatremia: Causes
• Hypovolemia • Extra-renal sodium loss (Una<10) » Sweat, diarrhea, vomiting » 3rd spacing: trauma, burns, pancreatitis • Renal sodium loss (Una >20) » Diuretics » Mineralocorticoid deficiency » Cerebral salt wasting » Proximal type II RTA • Euvolemia (Una>20) • SIADH • Glucocorticoid deficiency • Hypothryoidism • Psychogenic polydipsia • Drugs: desmopressin, psychoactive agents, chemotx
Hyponatremia: Causes
• Hypervolemia (Una<20) • Acute or chronic renal failure Una>20 • Congestive heart failure • Cirrhosis/hepatic failure • Nephrotic syndrome • Hyperosmolar • Hyperglycemia, mannitol, glycine
SIADH
• Causes • Intracranial pathology, mechanical ventilation, post operative, malignancy, neck surgery, pulmonary pathology • Diagnosis • Patient should be euvolemic • Labs: Serum osm, Urine osm, Una • Urine will be inappropriately concentrated for a patient who is hypoosmolar • Urine Na will be elevated and Urine output will be low • Treatment • 3% NS • Fluid restriction to 30-50% maintenance • Avoid excess free water-->make sure to check drips!
Hyponatremia: Therapy
• Correct rapidly with 3% NS for severely symptomatic patients • 4ml/kg 3%NS will increase [Na] by 5 • Normalize sodium at a rate of 8-12 mEq/L over 24 hours with 0.45% or 0.9% NS • Central pontine myelinolysis • may be irreversible • dysarthria, dysphagia, spastic paresis, coma • Check frequent sodiums (q1 or q2h)
3% NS
• Characteristics • 513 mEq/L • pH= 5.0
• 1027 mosm/L • Can be administered peripherally (in the acute setting) or centrally (recommended) • 3-5 ml/kg will raise serum sodium by 4-6 mEq/L • Adverse effects • Metabolic acidosis and hyperchloremia • Venous irritation/phlebitis
Hypernatremia
Hypernatremia: Clinical signs and symptoms
• Nausea/vomiting • Restless, irritable, or lethargic • Anorexia • Stupor/coma • Subarachnoid hemorrhage--Why?
Hypernatremia: Causes
• Free water loss • Diuretics (loop) • Post obstructive diuresis • Acute and chronic renal disease • Sweating, fistula, burns, diarrhea, vomiting • Diabetes insipidus (central, nephrogenic) • Sodium gain • Hypertonic saline or sodium bicarbonate • TPN • Hyperaldosteronism • Cushing’s syndrome
Hypernatremia: Therapy
• Risk of seizures and cerebral edema if corrected too rapidly • Correct hypovolemia with NS • Correct Na with 0.45% NS • Check Na frequently and adjust fluid therapy for a goal of 0.5-1mEq/L decrease qhour • Urine replacement (0.22% or 0.45% NS) • Vasopressin for central DI
Diabetes insipidus (central)
• Causes • Surgical resection, trauma, tumor infiltration, genetic, • Diagnosis • Rising Na and Serum osmolality • low Uosm and low Urine sg • increased UOP • Treatment • Urine replacement with 1/2 or 1/4 NS • Vasopressin infusion: titrate to UOP 3-4ml/kg/h • Na checks every hour
Body water SIADH Increased CSW decreased Sodium Serum osm low low <280mOsm/L decreased Urine osm >500mOsm/L increased Urine to serum osm ratio >1 >1 Urine output low high DI central decreased high Post resus diuresis Normal or increased normal >300mOsm/L decreased Normal (280 290mOsm/L) variable <1.5
variable high high Urine sodium increased increased decreased variable
Case 2
Case 2
• 15 yo male playing linebacker for high school football team presents in August with syncope, weakness, and palpitations. Bedside I-stat : 7.22/32/98/12/-9 Na 136 K 7 Gluc 189 iCa 0.7
• Cardiac monitors indicated the following:
Case 2
• What is this rhythm?
In case you were wondering, this is BAD!!!!
Case 2
• What electrolyte disturbances does this patient have?
• Hyperkalemia • Metabolic acidosis • Hypocalcemia • What therapies would you initiate? • Calcium gluconate 100mg/kg • Sodium bicarbonate 1mEq/kg • Insulin 0.1 units/kg + D10 or D25 2ml/kg • Kayexalate PR • What other lab studies are needed? • BMP, Mg, Phos, Lactate, CK, Tox screen, Serum osmolality
Case 2
• HR 130 RR 28 BP 90/50 98% on 2L • Obese male, tachypneic, diaphoretic, able to talk, clear breath sounds, no murmur, thready pulses • Na 137 K 7.5 HCO3 12 BUN 28 Creat 1.6 Gluc 190 Ca 6 Mg 1.1 Phos 6 • CK 45000
Case 2
• Despite initial therapies, patient remains hyperkalemic • What would you do? • Continue to administer Na bicarb, insulin/glucose, Calcium gluconate • Place a hemodialysis catheter • Keep a defibrillator and hands-free pads nearby • What disease processes could cause this? • Acute renal failure • Tumor lysis syndrome • Rhabdomyolysis
Hypokalemia
Hypokalemia: Signs and symptoms
• Generalized muscle weakness • Paralytic ileus • Cardiac arrhythmias • Atrial tachycardia • AV dissociation • EKG changes • Flat/inverted T waves • ST segment depression • U waves • Ascending paralysis and impaired respiratory function (K<2)
EKG in hypokalemia
Hypokalemia: Causes
• Renal loss – Primary hyperaldosteronism, hypothermia, genetic syndromes (i.e. Liddle’s), type I and II RTA, drugs (I.e. amphotericin, foscarnet) • GI loss – Vomiting, diarrhea (VIPoma, enteric fistula, malabsorption, jejunoileal bypass) • Transcellular shift Alkalosis, beta agonists, caffeine, insulin, thryrotoxicosis, hypokalemic periodic paralysis
Hypokalemia: treatment
• Determine the cause • When to correct?
• How much?
– 0.5-1 mEq/kg over 1 hour • What to use?
– KCl po or IV – KPhos
Hyperkalemia
Hyperkalemia
• Definition: K>6 mEq/L • Symptoms • EKG changes: peaked T waves, prolonged PR interval, widened QRS, V-fib • Muscle weakness/paresthesias
Hyperkalemia: Causes
• Impaired excretion • Renal failure, mineralocorticoid deficiency, drugs, type IV RTA, • Iatrogenic • Transcellular shift • Acidosis, beta blockers, digitalis overdose, somatostatin • Other • Tumor lysis • rhabdomyolysis
Hyperkalemia: Treatment
• Calcium gluconate • 100mg/kg IV peripheral or central • Insulin/glucose • Insulin 0.1units/kg IV • Glucose 2ml/kg D10 or D25 • The most effective way to quickly lower K!!!
• Sodium bicarbonate • 1-2mEq/kg • Hemodialysis • Kayexalate • 1gram/kg po or PR
Ca, Mg, Phos
Calcium homeostasis
Hormone
Calcium Phosphate PTH Vitamin D
Increase Increase
Calcitonin
Decrease Kidney reabsoption of Ca decreased Increased absorption in kidney and intestine increased Decreased absorption in kidney Increased absorption in kidney and intestine Decreased bone resorption/ decreased kidney reabsorption No effect
Hypocalcemia
• Symptoms appear when iCa<0.7
• Symptoms include: • Neuromuscular irritability (tetany) • Paresthesias of hands/feet • Circumoral numbness • Laryngospasm or bronchospasm • Anxious/irritable/depressed/confused • Hypotension • Rickets • EKG changes include: • Prolonged QT • Non-specific ST-Twave changes
Hypocalcemia: Causes and Diagnosis
• Determine the cause • PTH level • Vitamin D levels (25OHD3 and 1,25OHD3) • 24 hour urine calcium • Hypoparathyroidism • Irradiation, surgery, hypomagnesemia, DiGeorge, polyglandular autoimmune syndrome, storage disease, HIV • Vitamin D deficiency • Malnutrition, malabsorption, hepatobiliary disease, low sun exposure
Hypocalcemia: Causes
• Calcium chelation/precipitation • Tumor lysis, rhabdomyolysis, citrate, foscarnet • Multifactorial • Sepsis, pancreatitis, burns
Hypocalcemia: Treatment
• Calcium gluconate • 25-100mg/kg IV • Calcium chloride • 10-20 mg/kg IV • Must be given centrally • Treat low Magnesium • Treat underlying disease • When should you avoid treating hypocalcemia?
• Tumor lysis syndrome (unless patient is symptomatic)
Hypomagnesemia: Symptoms
• Symptoms: • Refractory hypocalcemia • Diarrhea • Ventricular arrhythmias • Muscle weakness, tremors, tetany • Causes • Decreased intake or malabsorption • Decreased renal reabsorption (familial, diuretics, amphotericin, bartters’s, gitelman’s • Transcellular shift (hyperaldosteronism, pancreatitis, respiratory alkalosis, catecholamines)
Hypomagnesemia
• Treatment • Magnesium sulfate 25-50 mg/kg • Replace potassium and calcium • Oral supplementation
Hypophosphatemia
• Symptoms • Muscle weakness, paralysis • Respiratory depression • Leukocyte and platelet dysfunction • Hemolysis • Causes • Decreased intake or malabsorption • Decreased renal reabsorption (hyperparathyroidism, fanconi ’s, vitamin D deficiency, medications) • Transcellular shift (catecholamines, theophylline, respiratory alkalosis)
Hypophosphatemia: Treatment
• Determine underlying cause (many times it is multifactorial) • Replace using: • NaPhos • Kphos 0.08-0.32 mmol/kg over 4-6 hours