What are normal ABG values?
An acceptable normal range of ABG values of ABG components are the following,[6][7] noting that the range of normal values may vary among laboratories and in different age groups from neonates to geriatrics: pH (7.35-7.45) PaO2 (75-100 mmHg) PaCO2 (35-45 mmHg)
What is normal PCO2 level?
The partial pressure of carbon dioxide (PCO2) is the measure of carbon dioxide within arterial or venous blood. It often serves as a marker of sufficient alveolar ventilation within the lungs. Generally, under normal physiologic conditions, the value of PCO2 ranges between 35 to 45 mmHg, or 4.7 to 6.0 kPa.
What is normal base excess on ABG?
A typical reference range for base excess is −2 to +2 mEq/L. Comparison of the base excess with the reference range assists in determining whether an acid/base disturbance is caused by a respiratory, metabolic, or mixed metabolic/respiratory problem.
What is the normal Bicarb level?
Normal bicarbonate levels are: 23 to 30 mEq/L in adults.
What happens if pCO2 is high?
The pCO2 gives an indication of the respiratory component of the blood gas results. A high and low value indicates hypercapnea (hypoventilation) and hypocapnea (hyperventilation), respectively. A high pCO2 is compatible with a respiratory acidosis and a low pCO2 with a respiratory alkalosis.
How do you interpret ABG base excess?
A high base excess (> +2mmol/L) indicates that there is a higher than normal amount of HCO3– in the blood, which may be due to a primary metabolic alkalosis or a compensated respiratory acidosis.
What is a high pCO2 level?
Why does An ABG not measure oxygen saturation?
Infrequently, ABGs will actually represent a venous or mixed sample. The oxygen extraction of the hand isn’t very high, so the level of oxygen in these venous samples may be only slightly lower than arterial blood. Thus, it may not be obvious that the sample was venous. #5. Point-of-care ABG analyzers don’t actually measure oxygen saturation
How is an ABG used to diagnose respiratory failure?
The A-a gradient is the difference in oxygen tension between arterial blood and alveolar gas. Medical school courses love this. However, trying to use the ABG to diagnose the etiology of respiratory failure works poorly in real life: A normal A-a gradient doesn’t exclude pulmonary embolism ( Stein 1995 ).
When to use an ABG instead of pulse oximetry?
The most common situation where ABG is needed to test oxygenation is when pulse oximetry cannot provide a reliable waveform. For example, some patients have non-pulsatile blood flow from a ventricular assist device (VAD) or ECMO.
Why is the ABG often wrong for hypoxemic patients?
The usual assumption is that the ABG reflects the patient’s ongoing condition (for example, if the patient was hypoxemic 15 minutes ago, then they must still be hypoxemic now). This assumption is frequently wrong. #10. Changes in PaO2 are widely misinterpreted.
