Brief Answer: Mildest Respiratory alkalosis, no worries Detailed Answer: Thank you for asking! Normal level of Carbon dioxide in arterial blood gases is 4.7-6.0 kPa or 35-45 mmHg.Now your level of 33 is almost normal though previous figure of 28 was respiratory alkalosis. If you have been a victim of any metabolic disorder like alkalosis or acidosis either metabolic or respiratory then keep having a keen eye on these gases levels. Right now there is nothing to worry about. It needs a complete clinical correlation for this alkalosis as some times excessive breathing can also reduce carbon dioxide levels. Respiratory alkalosis is a disturbance in acid and base balance due to alveolar hyperventilation. Alveolar hyperventilation leads to a decreased partial pressure of arterial carbon dioxide (PaCO2). In turn, the decrease in PaCO2 increases the ratio of bicarbonate concentration to PaCO2 and, thereby, increases the pH level, thus the descriptive term of respiratory alkalosis. The decrease in PaCO2 (hypocapnia) develops when a strong respiratory stimulus causes the respiratory system to remove more carbon dioxide than is produced metabolically in the tissues. Respiratory alkalosis can be acute or chronic. In acute respiratory alkalosis, the PaCO2 level is below the lower limit of normal and the serum pH is alkalemic. In chronic respiratory alkalosis, the PaCO2 level is below the lower limit of normal, but the pH level is relatively normal or near normal. Respiratory alkalosis is the most common acid-base abnormality observed in patients who are critically ill. It is associated with numerous illnesses and is a common finding in patients on mechanical ventilation. Many cardiac and pulmonary disorders can manifest with respiratory alkalosis as an early or intermediate finding. When respiratory alkalosis is present, the cause may be a minor non – life-threatening disorder. However, more serious disease processes should also be considered in the differential diagnosis. Now as i said The treatment of respiratory alkalosis is primarily directed at correcting the underlying disorder. Respiratory alkalosis itself is rarely life threatening. Therefore, emergent treatment is usually not indicated unless the pH level is greater than 7.5. Because respiratory alkalosis usually occurs in response to some stimulus, treatment is usually unsuccessful unless the stimulus is controlled. If the PaCO2 is corrected rapidly in patients with chronic respiratory alkalosis, metabolic acidosis may develop due to the renal compensatory drop in serum bicarbonate. SO seek a pulmonologist for further management and a complete clinical correlation though you have nothing to worry about right now as these levels of CO2 are fine. I hope it helps. Dont forget to close the discussion please. Take care. S Khan

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