ABG 简明血气分析.ppt

Respiratory Alkalosis pH 7.50 PaCO2 30 HCO3 22 Metabolic Acidosis pH 7.30 PaCO2 40 HCO3 15 Metabolic Alkalosis pH 7.50 PCO2 40 HCO3 30 What are the compensations? Respiratory acidosis ? metabolic alkalosis Respiratory alkalosis ? metabolic acidosis In respiratory conditions, therefore, the kidneys will attempt to compensate and visa versa. In chronic respiratory acidosis (COPD) the kidneys increase the elimination of H+ and absorb more HCO3. The ABG will Show NL pH, CO2 and HCO3. Buffers kick in within minutes.Respiratory compensation is rapid and starts within minutes and complete within 24 hours.Kidney compensation takes hours and up to 5 days. Mixed Acid-Base Abnormalities Case Study No. 3: 56 yo neurologic dz required ventilator support for several weeks.She seemed most comfortable when hyperventilated to PaCO2 28-30 mmHg.She required daily doses of lasix（速尿） to assure adequate urine output and received 40 mmol/L IV K+ each day.On 10th day of ICU her ABG on 24% oxygen VS: ABG Results pH 7.62 BP 115/80 mmHg PCO2 30 mmHg Pulse 88/min PO2 85 mmHg RR 10/min HCO3 30 mmol/L VT 1000ml BE 10 mmol/L MV 10L K+ 2.5 mmol/L Interpretation: Acute alveolar hyperventilation (resp. alkalosis) and metabolic alkalosis with corrected hypoxemia. Case study No. 4 27 yo retarded ? with insulin-dependent DM arrived at ER from the institution where he lived. On room air ABG VS: pH 7.15 BP 180/110 mmHg PCO2 22 mmHg Pulse 130/min PO2 92 mmHg RR 40/min HCO3 9 mmol/L VT 800ml BE -30 mmol/L MV 32L Interpretation: Partly compensated metabolic acidosis. Case study No. 5 74 yo ? with hx chronic renal failure and chronic diuretic therapy was admitted to ICU comatose and severely dehydrated. On 40% oxygen her ABG VS: pH 7.52 BP 130/90 mmHg PCO2 55 mmHg Pulse 120/min PO2 92 mmHg RR 25/min HCO3 42 mmol/L VT 150ml BE 17 mmol/L MV 3.75L Interpretation: Partly compensated metabolic alka