Acid-Base

Card Set Information

Author:
Ambestul
ID:
12277
Filename:
Acid-Base
Updated:
2010-03-31 08:22:01
Tags:
renal quiz 4
Folders:

Description:
acid-base disturbances
Show Answers:

Home > Flashcards > Print Preview

The flashcards below were created by user Ambestul on FreezingBlue Flashcards. What would you like to do?


  1. Normal [H]
    0.00004 mEq/L or 40 mEq/L
  2. Modified Henderson-Hasselbach equation
    pH=6.1+log[(HCO3)/(0.03 x PCO2)]
  3. pK of bicarbonate
    6.1-most important for physiologic buffering system, regulated by kidney
  4. pK of phophate
    6.8, most useful in intracellular
  5. time it takes for respiratory compensation
    occurs in minutes, max effect 12-24 hours, chemical buffer system is first-line and immediate but limited in scope
  6. time it takes for metabolic compensation
    responds within hours, max effect within 2-5 days, takes longer and max effect takes longer
  7. normal ratio of PCO2/HCO3
    24
  8. metabolic acidosis
    decreased pH, decreased HCO3, compensation decrease PaCO2
  9. respiratory acidosis
    decrease pH, increase in PaCO2, compensate increase in HCO3
  10. metabolic alkalosis
    increased pH, increased HCO3, compensate by increase PaCO2
  11. respiratory alkalosis
    increased pH, decreased PaCO2, compensated decrease HCO3
  12. Winter's equation-metaboic acidosis
    Paco2=[(1.5 x HCO3) +8] +-2
  13. Winter's Equation-Metabolic alkalosis
    PaCO2=40 + [(HCO3-25) x 0.6 +-2
  14. Repiratory Acidosis-compensation for acute
    Acute: pH = 7.4 – [(PaCO2 –40) x 0.008] +- 0.02
  15. Respiratory acidosis-compensation for chronic
    Chronic (> 12-24 hrs): pH = 7.4 –[(PaCO2 –40) X 0.003] +_ 0.02
  16. Respiratory alkalosis-compensation for acute
    Acute: pH= 7.4 + [(40-PaCO2) x 0.008] +- 0.02
  17. Respiratory alkalosis-compensation for chronic
    Chronic (> 6-12 hrs): pH= 7.4 + [(40-PaCO2) x 0.003] +- 0.02
  18. normal pH range
    7.35-7.45
  19. normal range of PaCO2
    partial pressure arterial carbon dioxide, 35-45 mmHg
  20. normal range PaO2
    partial pressure arterial oxygen 80-100 mmHg
  21. HCO3 normal range
    calculated value 22-26 mEq/L
  22. verify accuracy
    HCO3 of ABG to HCO3 (or CO2) from blood chemistry panel, or calculated pH to pH from ABG
  23. amount of variation of pH when comparing
    plus or minus 0.02
  24. amount of variation of difference in HCO3
    plus or minus 2
  25. Anion gap
    Calculation: Na - [(Cl + HCO3)]=about 9 (3-12)
  26. increased antion gap means:
    ↑ Anion Gap (> 12) = accumulation of unmeasured anions, calculate especially for metabolic acidosis but also for others to not miss a toxicology
  27. Metabolic acidosis
    pH <7.35 HCO3<22
  28. Respiratory acidosis
    pH <7.35 PaCO2>45
  29. Metabolic alkalosis
    pH >7.45 HCO3>26
  30. Respiratory alkalosis
    pH>7.45 PaCO2<35
  31. increased anion gap metabolic acidosis (AGMA)
    “KUSMAL” Æ Ketoacidosis, Uremia, Salicylate, Methanol, Antifreeze, (ethylene glycol), Lactic acidosis
  32. Non Anion Gap metabolic acidosis (NAGMA) or hyperchloremic metabolic acidosis
    USEDCART-urrethral diversions, small bowel, exogenous chloride, diarrhea, carbonic anhydrase inhibitors, adrenal insufficiency, renal tubular acidosis, topamax
  33. Life threatening metabolic acidosis
    (HCO3- < 8 mEq/L or pH < 7.2)
  34. treatment for life threatening metabolic acidosis
    IV sodium bicarb
  35. calculate bicarb deficit
    Base deficit (mEq) = 0.5 x Kg x (desired HCO3 - observed HCO3- )
  36. desired HCO3 and pH to treat to for metabolic acidosis with IV sodium bicarb
    10 mg/L and pH NMT 7.20
  37. alternative treatment of life-threatening metabolic acidosis and when to use?
    Tromethamine (THAM)- (150 mEq/500 ml or 0.3 N solution), LOTS of SEs, only use in cardiac transplantation
  38. dose of THAM (2 possible)
    • ml of THAM=1.1 x Kg x (desired HCO3-observed HCO3)
    • OR
    • 1-5mM/kg over 1 hr
  39. treatment of asymptomatic or chronic acidemia
    oral bicarb replacement,administer over 3-5 days to avoid volume overload followed by maintenance 1-3 mEq base/Kg/day if metaboic acidosis persists
  40. dose of sodium bicarb tablets
    • 325 and 650
    • each 650 mg tab=7.7 mEq HCO3
  41. citrate and citric acid solutions
    citrate metabolized to bicarb by liver
  42. Sodium citrate/citric acid (Bicitra®, Shohls Solution)
    Each ml contains 1 mEq Na+ & 1 mEq HCO3
  43. Potassium citrate/citric acid (Polycitra®)
    each ml contains 1 mEq Na, 1 mEq K and 2 mEq HCO3, don't use in CKD
  44. other option for chronic or asymptomatic acidemia
    • IV sodium acetate or sodium lactate,
    • Metabolized to HCO3
    • -
    • Substituted for usual chloride salts in TPN
  45. 3rd option for asymptomatic or chornic acidemia
    dialysis, if already have access, for severe life-threatening metabolic acidosis
  46. Chloride responsive-Urine Cl<10 meq/L, pH 7.45-7.6
    • 1. 0.9% NaCl +/- KCL
    • 2. Acetazolamide
  47. Chloride responsive-Urine Cl<10 meq/L, pH >7.6
    • 1. HCL
    • 2. NH4Cl
    • 3. Arginine
    • 4. Dialysis
  48. chloride-resistant
    urine Cl > 20 mEq/L


    • 1. Correct underlying problem
    • 2. Potassium repletion if K < 3.5
  49. monitoring for metabolic alkalosis
    Measure ABG’s & serum K+ every 2-4 hrs depending upon severity
  50. Sodium Chloride Responsive
    • 1. treat underlying cause
    • 2. Replace volume with 0.9% NaCl & add KCL as necessary
  51. Acetazolamide - if volume or sodium intolerant & add KCL if needed
    • 􀂃 Carbonic Anhydrase inhibitor diuretic
    • 􀂃 Promotes bicarbonate diuresis
    • 􀂃 Dose: 250 – 375 mg IV or PO qd - bid
    • 􀂃 Onset w/in 2 hrs; max effect w/in 15 hrs; duration 24 hours
  52. Acid Replacement - calculate chloride deficit(base excess)
    (a) Cl (mEq) deficit = 0.5 x Kg x (desired HCO3 - observed HCO3 ) (b) CL (mEq) deficit = 0.2 x Kg x ( 103 - observed Cl-)
  53. Ammonium chloride (100 mEq H+ in 20 ml) Æ Add to 500 cc NS
    • 1. combines with CO2 and releases HCL following hepatic metabolism to urea
    • 2. CNS toxicity limits dose/rate of infusion
    • 3. calc Cl deficit and admin 1/2 avoid ammonium overload
    • 4. recomm max adult dose=20gm (374 mEq H)/24 hr
    • 5. recom max peds dose=16mg/kg IV or 75 mg/kg PO qd
    • 6. caution in pts with liver(enchephalopathy) or reanl disease(uremia)
  54. Arginine HCL
    • a.300 ml (10% soln)=142.5 mEq of HCl via hepatic metabolism
    • b. infuse 10g/hr
    • c. caution: pts with CKD (increase K & BUN)
  55. Sodium Chloride Resistant
    • a. correct underlying
    • b. exogenous cs admin-dec dose
    • c. endo cs source-surgery
    • d. spironolactone-mc receptor antag
    • e. aggressive potassium replacement
  56. Treatment of respiratory acidosis
    • treat underlying
    • restore/maintain airway
    • oxygen
  57. causes of respiratory acidosis
    • Perfusion Abnormalities;
    • Airway obstruction
    • Aspiration
    • COPD
    • Neuromuscular Abnormalities;
    • Trauma, stroke Brainstem or cervical cord injury Guillain-Barre’ syndrome Myasthenia gravis Status epilepticus Narcotic or sedative overdose Obesity, Poliomyelitis, MS Tumors
    • Miscellaneous;
    • Mechanical ventilator malfunction Overfeeding with TPN (RQ > 1)
  58. causes of respiratory alkalosis
    • central stimulation of respiration:
    • Anxiety Pain Fever Brain tumors, CVA’s Head trauma Infections Pregnancy Progesterone Catecholamines, Theophylline Salicylates Nicotine Peripheral stimulation of respiration;
    • Pulmonary emboli CHF Altitude Asthma Hypotension Pneumonia Interstitial lung damage
    • Miscellaneous;
    • Hepatic cirrhosis Gram negative sepsis Heat exposure
  59. treatment for respiratory alkalosis
    • identify and treat underlying
    • re-breathing device
    • adjust mechanical ventilation
  60. Algorithm-metabolic acidosis
    • 1. Verify
    • Accuracy
    • Compare HC03 from ABG’s with HC03 (or CO2) on Chemistry panel or calculate HC03 or pH using modified Henderson-
    • Hasselbach Equation
    • 2. Identify
    • Primary
    • Disorder

    • pH < 7.35 & HCO3
    • - < 22
    • 3. Calculate
    • Expected
    • Compensation
    • Winter’s Equation:
    • PaCO2 = [(1.5 x HCO3) + 8] ± 2
    • 4. Identify
    • Mixed
    • Disorder
    • Observed < Expected →
    • Co- Respiratory Alkalosis
    • Observed >Expected →
    • Co - Respiratory Acidosis
    • 5. Identify
    • Other
    • Metabolic
    • Problems
    • Calculate Anion Gap
    • Na+ - (Cl- + HCO3
    • -) = 3-11
    • ↑ Anion Gap (>12) →AGMA
    • Anion Gap < 12 → NAGMA
    • 6. Treat
    • Appropriately
    • • Bicarb (IV / PO)
    • • Na Acetate or Na Lactate
    • • THAM
    • • Dialysis
  61. algorithm-metabolic alkalosis
    • Metabolic Alkalosis
    • pH > 7.45 & HCO3
    • - > 26
    • 3. Calculate
    • Expected
    • Compensation
    • Winter’s Equation:
    • PaC02 =
    • 40 + [(HC03 – 25) x 0.6] ±2
    • 4. Identify
    • Mixed
    • Disorder
    • Observed < Expected →
    • Co- Respiratory Alkalosis
    • Observed >Expected →
    • Co - Respiratory Acidosis
    • 5. Identify
    • Other
    • Metabolic
    • Problems

    • Calculate Anion Gap
    • (suggested)
    • Check Urine Chloride
    • Urine Cl < 10 mEq/L →
    • NaCl Responsive
    • Urine Cl > 20 mEq/L →
    • NaCl Resistant
    • Dependent on above Urine
    • Chloride
  62. algorithm-respiratory acidosis
    • Respiratory Acidosis - < 22
    • pH < 7.35 & PaCO2 > 45
    • 3. Calculate
    • Expected
    • Compensation
    • Acute:
    • pH = 7.4 –[ (PaCO2-40) x 0.008]
    • Chronic (> 12-24 hrs):
    • pH = 7.4 –[ (PaCO2-40) x 0.003]
    • 4. Identify
    • Mixed
    • Disorder

    • Observed < Expected →
    • Co -Metabolic Acidosis
    • Observed > Expected →
    • Co -Metabolic Alkalosis
    • 5. Identify
    • Other
    • Metabolic
    • Problems
    • Calculate Anion Gap
    • (suggested)
    • Restore/Maintain Airway
    • Oxygen
  63. algorithm-Respiratory Alkalosis
    • pH > 7.45 & PaCO2 < 35
    • 3. Calculate
    • Expected
    • Compensation
    • Acute:
    • pH = 7.4 + [(40- PaCO2) x 0.008]
    • Chronic (> 6-12 hrs):
    • pH = 7.4 +[ (40- PaCO2) x 0.003]
    • 4. Identify
    • Mixed
    • Disorder
    • Observed < Expected →
    • Co - Metabolic Acidosis
    • Observed > Expected →
    • Co - Metabolic Alkalosis
    • 5. Identify
    • Other
    • Metabolic
    • Problems
    • Calculate Anion Gap
    • (suggested)
    • Identify
    • Other Metabolic Problems
    • 6. Treat
    • Appropriately
    • Rebreathing device
    • Adjust mechanical
    • ventilation
  64. HCL (0.1 normal)
    • a. add NMT 100-250 mEq HCL to 500 ml glass container of D5W or NS
    • b. admin thru central line
    • c, infuse over 12-24 hours
    • d. ABGs and electrolytes q4-8hrs and adjust
    • e. DC when pH 7.5

What would you like to do?

Home > Flashcards > Print Preview