ABSTRACT
BLOOD GAS VALUES ■ Arterial pH 7.35-7.45 ■ Arterial oxygen pressure (PaO2) 75-100 mm Hg ■ Arterial carbon dioxide pressure (PaCO2) 35-45 mm Hg ■ Arterial oxygen saturation (SaO2) 95%-100% ■ Mixed venous oxygen pressure (PvO2) 38-42 mm Hg ■ Mixed venous oxygen saturation (SvO2) 70%-75%
INDICATIONS ■ To assess adequacy of oxygenation for diagnostic and ther-
apeutic purposes ■ To determine adequacy of ventilation or carbon dioxide
clearance ■ To assess acid-base status
OXYGENATION VARIABLES ■ Arterial oxygen saturation (SaO2) ■ Arterial oxygen content (CaO2) ■ Arterial oxygen pressure (PaO2) ■ Arterial carbon dioxide pressure (PaCO2) ■ Alveolar-arterial oxygen gradient [P(A-a)O2] ■ Arterial-alveolar oxygen ratio (PaO2/PAO2) ■ PaO2/FIO2 ratio (FIO2 = fraction of inspired oxygen)
Arterial Oxygen Saturation (SaO2) ■ Oxygen saturation of hemoglobin varies with PaO2. ■ With the sigmoid characteristic of oxygen saturation curve,
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(pO2) of 60 mm Hg (SaO2 of 90%).
