This document discusses acid-base disorders and interpretation of arterial blood gases (ABGs). It defines acidosis and alkalosis, and describes respiratory and metabolic causes. Simple and mixed acid-base disorders are explained. Compensation by the lungs and kidneys in response to primary disorders is discussed. A stepwise approach to ABG interpretation is provided, including determining the primary disorder, checking for compensation, calculating the anion gap, and identifying specific etiologies. Characteristics of simple acid-base disturbances and combined disorders are summarized.
26. COMPENSATORY RESPONSE pCO 3 = 55 HCO 3 = 55-40/10 x 4 = 1.5 x 4 = 6 6 + 24 = 30 CHRONIC RESPIRATORY ACIDOSIS HCO3 will increase 4 mmol/L per 10 mmHg increase in PaCO2
27. COMPENSATORY RESPONSE HCO 3 = 80-40/10 x 4 = 16 + 24 = 40 pCO 3 = 80 CHRONIC RESPIRATORY ACIDOSIS HCO3 will increase 4 mmol/L per 10 mmHg increase in PaCO2
28. COMPENSATORY RESPONSE RESPIRATORY ALKALOSIS Acute: HCO3 will decrease 2 mmol/L per 10 mmHg decrease in PaCO2 Chronic: HCO3 will decrease 4 mmol/L per 10 mmHg decrease in PaCO2
60. CASE 3 Expected PCO 2 = 6 x 0.75 = 4.5+40 = 44.5 CompensatedMetabolic Alkalosis serum Na 138 63 K 2.7 34 Cl 96 0 HCO 3 30 0 pH 7.45 5.6 pCO 2 45 Plasma Urine PaCO2 will increase 0.75 mmHg per 1 mmol/L increase in HCO3 from 24
61. CASE 3 Anion Gap = Na – (HCO3+Cl) 138 – (30+96) = 12 NAG Plasma Urine serum Na 138 63 K 2.7 34 Cl 96 0 HCO 3 30 0 pH 7.45 5.6 pCO 2 45
62. CASE 3 Plasma Urine serum Na 138 63 K 2.7 34 Cl 96 0 HCO 3 30 0 pH 7.45 5.6 pCO 2 45 What is the cause of the acid base disorder?
63. CASE 3 What is the cause of the acid base disorder? 1) diuretic intake 2) surreptitious vomiting 3) Bartter’s syndrome 4) Adrenal tumor 5) nonreabsorbable anion
64. CASE 3 How should her acid-base disorder be managed? 1) correct hypokalemia 2) hydrate with NSS 3) administer acidyfing agent 4) give carbonic anhydrase inhibitor
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72. CASE 4 admission after 48 hrs pH = acidosis pCO 2 =acidosis, HCO 3 = alk Respiratory Acidosis serum Na 136 139 K 3.2 3.9 Cl 78 86 HCO 3 40 38 pH 7.33 7.42 pCO 2 78 61 pO 2 43 56
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74. CASE 4 serum Na 136 139 K 3.2 3.9 Cl 78 86 HCO 3 40 38 pH 7.33 7.42 pCO 2 78 61 pO 2 43 56 admission after 48 hrs Expected HCO 3 = 78-40/10 = 3.8 + 24 = 27.8 Respiratory Acidosis & M. Alkalosis
75. CASE 4 serum Na 136 139 K 3.2 3.9 Cl 78 86 HCO 3 40 38 pH 7.33 7.42 pCO 2 78 61 pO 2 43 56 How should this patient be managed? admission after 48 hrs
76. CASE 4 1) intubation and mechanical ventilation 2) low flow oxygenation by nasal prong 3) oxygen by face mask 4) sodium bicarbonate infusion with KCl How should this patient be managed?