Table 10.2 Examples of Arterial Blood Gases in Different clinical Situations PO2, mm Hg Interpretation Example PCO2, mm Hg pH Likely causes Therapy 40 3 40– 0.03 90 5 Normal blood gas None 44 3 7.37 0.03 88 5 Normal blood gas while asleep Hyperventilation 22 7.57 106 Anxiety None Hypoventilation 68 7.10 58 Central nervous system Mechanical ventilation: depression; blockage relieve the cause of upper airway 58 7.21 39 Hypoventilation and Pneumonia; small-airway Oxygen; bronchodilators; hypoxemia obstruction; severe mechanical ventilation asthma 6.99 Birth asphyxia; 61 29 Combined respiratory Oxygen; mechanical and metabolic acidosis near-drowning ventilation; buffers? and hypoxemia 60 7.37 106 Chronic respiratory Patient has chronic lung Treat chronic disease acidosis with metabolic disease and is on oxygen no additional therapy compensation; patient may be necessary is receiving supplemental oxygen 29 7.31 106 Metabolic acidosis with Diabetic: ketoacidosis; Treat the cause: buffers? respiratory compensation dehydration SOURCE B. G. Nickerson and F. Monaco. “Carbon dioxide electrodes, arterial and transcutaneous,” in J. G.Webster (ed.), Encyclopedia of Medical Devices and Instrumentation. New York: Wiley, 1988, pp. 564-569.