Sandbox: sadaf: Difference between revisions
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| align="left" style="background:#F5F5F5;" + |Normal | | align="left" style="background:#F5F5F5;" + |Normal | ||
|- | |- | ||
! colspan="2" align="center" style="background:#DCDCDC;" + | | ! colspan="2" align="center" style="background:#DCDCDC;" + |Osmolar gap | ||
(Osmolality – Osmolarity) | (Osmolality – Osmolarity) | ||
| align="left" style="background:#F5F5F5;" + |>10 | | align="left" style="background:#F5F5F5;" + |>10 | ||
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|- | |- | ||
! colspan="2" rowspan="3" align="center" style="background:#DCDCDC;" + |[[Anion gap]] | ! colspan="2" rowspan="3" align="center" style="background:#DCDCDC;" + |[[Anion gap]] | ||
[Na] – {[Cl]+[ | [Na<sup>+</sup>] – {[Cl<sup>-</sup>]+[HCO3<sup>-</sup>]} | ||
| align="left" style="background:#F5F5F5;" + |<8 | | align="left" style="background:#F5F5F5;" + |<8 | ||
| align="left" style="background:#F5F5F5;" + |Low | | align="left" style="background:#F5F5F5;" + |Low |
Revision as of 14:14, 7 May 2018
Acid Base Disorders
Approach
Normal range
Blood gas analysis | Vessel | Range | Interpretation |
---|---|---|---|
Oxygen Partial Pressure (pO2) | Arterial | 80 to 100 mmHg (10.6 to 13.3 kPa) | Normal |
<80 mmHg | Hypoxia | ||
Venous | 35 to 40 mmHg | Normal | |
Oxygen Saturation (SO2) | Arterial | >95% | Normal |
<95% | Hypoxia | ||
Venous | 70 to 75% | Normal | |
pH | Arterial | <7.35 | Acidemia |
7.35 to 7.45 ([H+] 35 to 45 nmol/L) | Normal | ||
>7.45 | Alkalemia | ||
Venous | 7.26 to 7.46 | Normal | |
Carbon Dioxide Partial Pressure (pCO2) | Arterial | <35 mmHg | Low |
35 to 45 mmHg (4.7 to 6.0 kPa) | Normal | ||
>45 mmHg | High | ||
Venous | 40 to 45 mmHg | Normal | |
[HCO3-] | Arterial | <22 mmol/L | Low |
22 to 26 mmol/L | Normal | ||
>26 mmol/L | High | ||
Venous | 19 to 28 mmol/L | Normal | |
Base Excess (BE) | Arterial | <-3.4 | Acidemia |
-3.4 to +2.3 mmol/L | Normal | ||
>2.3 | Alkalemia | ||
Venous | -2 to -5 mmol/L | Normal | |
Osmolar gap
(Osmolality – Osmolarity) |
>10 | Abnormal | |
Anion gap
[Na+] – {[Cl-]+[HCO3-]} |
<8 | Low | |
8 to 16 | Normal | ||
>16 | High |
Compensation formula
Primary disorder | pH | PaCO2 | [HCO3-] | Compensation |
---|---|---|---|---|
Metabolic acidosis | ↓ | ↓ | ↓ | Respiratory |
Metabolic alkalosis | ↑ | ↑ | ↑ | Respiratory |
Respiratory acidosis | ↓ | ↑ | ↑ | Renal |
Respiratory alkalosis | ↑ | ↓ | ↓ | Renal |
Approach to acid–base disorders
Check pH on ABG | |||||||||||||||||||||||||||||||||||||||||
pH < 7.35=Acidosis | pH > 7.45=Alkalosis | ||||||||||||||||||||||||||||||||||||||||
Check PaCO2 | |||||||||||||||||||||||||||||||||||||||||
PaCO2 > 45mm Hg = Respiratory acidosis | PaCO2 Normal or < 35mm Hg = Metabolic acidosis | Check PaCO2 | |||||||||||||||||||||||||||||||||||||||
PaCO2 > 45mm Hg = Metabolic alkalosis | PaCO2 < 35mm Hg = Respiratory alkalosis | ||||||||||||||||||||||||||||||||||||||||
[HCO3-] > 29 | Check [HCO3-] | ||||||||||||||||||||||||||||||||||||||||
Normal or slight decrease = Acute respiratory alkalosis | Decreased < 24 = Chronic respiratory alkalosis | ||||||||||||||||||||||||||||||||||||||||
Management of Acidosis
pH < 7.35 | |||||||||||||||||||||||||||||||||||||||||||||||||||
Acidosis | |||||||||||||||||||||||||||||||||||||||||||||||||||
Determine the primary disorder Metabolic or respiratory? | |||||||||||||||||||||||||||||||||||||||||||||||||||
Check [HCO3-] and PaCO2 | |||||||||||||||||||||||||||||||||||||||||||||||||||
Low [HCO3-] and Low to normal PaCO2 | High PaCO2 and High to normal [HCO3-] | ||||||||||||||||||||||||||||||||||||||||||||||||||
Metabolic acidosis | Respiratory acidosis | ||||||||||||||||||||||||||||||||||||||||||||||||||
Check for respiratory compensation Calculate expected PCO2 | Check for renal compensation Calculate expected [HCO3-] | ||||||||||||||||||||||||||||||||||||||||||||||||||
Decrease in PaCO2=1.25 x (24- measured HCO3-)? | Acute acidosis? Increase [HCO3-]=0.1 x (measure PaCO2-40)? | Chronic acidosis? Increase [HCO3-]=0.1 x (measure PaCO2-40)? | |||||||||||||||||||||||||||||||||||||||||||||||||
PaCO2 too low? Mixed metabolic acidosis with respiratory alkalosis | PaCO2 too high? Mixed metabolic acidosis with respiratory acidosis | [HCO3-] too low? Mixed respiratory acidosis with metabolic acidosis | [HCO3-] too high? Mixed respiratory acidosis with metabolic alkalosis | [HCO3-] too low? Mixed respiratory acidosis with metabolic acidosis | E04=[HCO3-] too high? Mixed respiratory acidosis with metabolic alkalosis | ||||||||||||||||||||||||||||||||||||||||||||||
Measured PaCO2 is equal to expected value? Compensated metabolic acidosis | Measured [HCO3-] is equal to expected value? Compensated respiratory acidosis | Measured [HCO3-] is equal to expected value? Compensated respiratory acidosis | |||||||||||||||||||||||||||||||||||||||||||||||||
Click here for the management of metabolic acidosis | Click here for the management of respiratory acidosis | ||||||||||||||||||||||||||||||||||||||||||||||||||
Approach to Metabolic Acidosis
pH<7.35 And [HCO3-]<24 meq/L | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Metabolic acidosis | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Calculate the anion gap (AG) Na+ - Cl- - HCO3- | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Low AG AG<8 | Normal AG 8<AG<16 | High AG AG>16 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
Check albumin Correct the AG if albumin is low For every decrease of 1 g/dl of albumin, AG is decreased by 2.5 meg/L | Check Ca2+, Mg2+, K+, immunoglobulins High levels of these unmeasured cations decrease the AG | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Check urine AG Na+ + K+ - Cl- | Check ΔAG/ΔHCO3- | R/O low Ca2+, Mg2+, K+ | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
Negative urine AG GI causes RTA type II | Positive urine AG Renal failure RTA type I RTA type IV | ΔAG/ΔHCO3-<1 High AG metabolic acidosis combined with normal AG metabolic acidosis | 1<ΔAG/ΔHCO3-<2 Pure high AG metabolic acidosis | ΔAG/ΔHCO3->2 High AG metabolic acidosis combined with metabolic alkalosis | |||||||||||||||||||||||||||||||||||||||||||||||||||||
Metabolic Acidosis
Disease | PH | Poisoning | AG | Loss of consciousness | Fever | ||||
---|---|---|---|---|---|---|---|---|---|
Methanol | Low | Yes | High | ||||||
Metformin | Low | High | |||||||
Uremia | Low | High | |||||||
Diabetic ketoacidosis | Low | High | |||||||
Paraldehyde | Low | Yes | High | ||||||
Propylene glycol | Low | Yes | High | ||||||
Infection | Low | High | |||||||
Ischemia | Low | High | |||||||
Isoniazid | Low | High | |||||||
Ethylene glycol | Low | Yes | High | ||||||
Ethanol | Low | Yes | High | ||||||
Salicylates | Low/high | Yes | High | ||||||
Starvation | Low | High | |||||||
Diarrhea | Low | Nl | |||||||
Ureteral diversion | Low | Nl | |||||||
Renal tubular acidosis | Low | Nl | |||||||
Hyperalimentation | Low | Nl | |||||||
Addison's disease | Low | Nl | |||||||
Acetazolamide | Low | Nl | |||||||
Ammonium chloride | Low | Nl | |||||||
Congenital chloride diarrhea | Low | Nl | |||||||
Amphotericin B | Low | Nl | |||||||
Toluene | Low | Nl | |||||||
Cholestyramine | Low | Nl | |||||||
post hypocapnea | Low | Nl | |||||||