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arterial blood gas (ABG)

Indications: - evaluation of acid-base status - ventilation-perfusion abnormalities - hypoxemia - hypercarbia Normal range: - room air - pO2: 70-100 mm Hg - pCO2: 35-45 mm Hg - pH:* 7.38-7.44 (H+ 40 nmol/L) * pH measurements may be obtained from venous blood, collected & analyzed as arterial blood. pH values are a mean of -0.04 pH units lower with venous blood (2 SDs -0.11 to + 0.04) [2]. In the elderly, pO2 (PaO2) is generally less than that in younger patients. (see PaO2) Clinical significance: 1) arterial blood is used to measure a) oxygen (O2) b) carbon dioxide (CO2) c) pH 2) these measurements are important for establishing a) acid-base status b) ventilation-perfusion abnormalities 3) consider use of pulse oximetry plus transcutaneous CO2 if pH not needed Procedure: - arteries of choice for obtaining specimen: a) radial artery b) brachial artery c) femoral artery

Related

base excess transcutaneous blood gas monitoring

General

chemistry panel

References

  1. Clinical Diagnosis & Management by Laboratory Methods, 19th edition, J.B. Henry (ed), W.B. Saunders Co., Philadelphia, PA. 1996
  2. Journal Watch 21(24):196, 2001 - Kelly AM, McAlpine R, Kyle E. Venous pH can safely replace arterial pH in the initial evaluation of patients in the emergency department. Emerg Med J. 2001 Sep;18(5):340-2. PMID: 11559602 Free PMC Article
  3. Treger R, Pirouz S, Kamangar N, Corry D. Agreement between central venous and arterial blood gas measurements in the intensive care unit. Clin J Am Soc Nephrol. 2010 Mar;5(3):390-4. PMID: 20019117 Free PMC Article
  4. Wagner PD. The physiological basis of pulmonary gas exchange: implications for clinical interpretation of arterial blood gases. Eur Respir J. 2015 Jan;45(1):227-43. Review. PMID: 25323225 Free Article

Component-of

coma panel

Components

partial pressure of carbon dioxide (paCO2) in arterial blood partial pressure of oxygen in arterial blood (PaO2) pH in blood