The body has three main buffers that minimise any changes in pH that occur when acids or bases are added, namely haemoglobin, HCO3 — and proteins. However, HCO3 — is the most important buffer in the blood and is the dominant buffer in the interstitial fluid. At an intracellular level buffering occurs instantly, but the effect is small. The following are the commonly reported parameters of ABG results see Box 2 for the normal reference ranges :.
Other parameters commonly found on ABG reports are: haemoglobin, glucose and electrolytes sodium, potassium, chloride and ionised calcium. The pH should be assessed first. A pH of less than 7. Having determined if the patient is acidotic or alkalotic, check the HCO3 — and the PaCO 2 to classify the results as follows:. It is possible for patients to have a mixed respiratory and metabolic alkalosis or acidosis.
This occurs when primary respiratory and primary metabolic disturbances exist simultaneously. If the two processes oppose each other, pH derangement will be minimised see step 3. Check to see if the patient is compensating for his or her acid-base imbalance.
This may create some apparently normal results amongst some deranged ones. When interpreting acid-base status, it is important always to take the clinical context into account.
For example, if presented with ABG results showing a normal pH, low PaCO 2 and low HCO 3 — in a diabetic patient with high levels of ketones in urine the most likely primary disorder is metabolic acidosis diabetic ketoacidosis , rather than respiratory alkalosis see Box 3. For a patient with metabolic acidosis it can be useful to calculate the anion gap because this can give some indication of the underlying cause of the acid-base imbalance.
The following equation can be used to estimate the anion gap:. If possible, the underlying cause of the acid-base derangement should be treated because without doing this the problem can recur. In some instances, it may not be possible to treat the underlying cause and drug treatment may be required to correct the acid-base imbalance. Someone who is hyperventilating breathes very deeply or rapidly. Panic attacks and anxiety are the most common causes of hyperventilation.
Others include:. Make an appointment with your doctor. Overbreathing is a sign that respiratory alkalosis is likely to develop. However, low carbon dioxide levels in the blood also have a number of physical effects, including:. Treating the condition is a matter of raising carbon dioxide levels in the blood. The following strategies and tips are useful for respiratory alkalosis caused by overbreathing due to panic and anxiety.
Doing this several times can give the body the carbon dioxide it needs and bring levels back up to where they should be. The symptoms of respiratory alkalosis can be frightening. This often causes faster and deeper breathing, making things worse. Having a calm loved one provide reassurance could help get your breathing under control.
To do this, try breathing while pursing the lips or breathing through one nostril. For the second approach to be useful, the mouth and the other nostril need to be covered. The above strategies are very simple ways to address respiratory alkalosis. People who often experience overbreathing due to anxiety can use these methods at home. Anyone experiencing overbreathing and the symptoms of respiratory alkalosis for the first time should go to the hospital right away.
The strategies described in the previous section should only be used if a doctor has confirmed the exact cause of overbreathing. Overbreathing symptoms are very similar to the symptoms of other serious health conditions. The recovery process depends on the cause. If you develop respiratory alkalosis due to conditions such as anxiety, you can usually expect to recover fully. Symptoms should disappear shortly after carbon dioxide levels in the blood are brought back to normal.
In other cases, it may be a true medical emergency. The outlook will then depend on the severity of the underlying cause. Prevention is a matter of addressing the cause of hyperventilation. The most common causes are psychological: stress, panic, and anxiety.
You can adjust to and learn to control these causes. For more information about blood gases and interpretation of acid base abnormalities, refer to Bicarbonate under our Chemistry section of eClinPath. Phone: Fax: Email: diagcenter cornell. Business Hours Monday-Friday: ampm Saturdays limited service : ampm. Bring to lab immediately after collection. Remove needles from syringes!! DO NOT leave the sample without notifying someone in the lab that the sample has arrived. Venous blood gas pO2, pCO2, pH, bicarb.
CO2, base excess. A low pH is compatible with acidemia and a high pH with alkalemia. It is the partial pressure tension of oxygen in a gas phase in equilibrium with blood. High or low values indicate blood hyperoxia or hypoxia, respectively. It is the partial pressure of pCO2 in a gas phase in equilibrium with the blood.
The pCO2 gives an indication of the respiratory component of the blood gas results.
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