Introduction:
The human body works continuously to maintain the body's acid-base (alkali) balance. When the amount of alkali in the body increases, it is said to be alkalosis. Changes in metabolism or breathing can be seen with chemical changes in the acid-base balance.
What Is Respiratory Alkalosis?
Respiratory alkalosis is not a disease, but it is a symptom that occurs secondary to other problems, such as hyperventilation. In hyperventilation, a person starts breathing too fast, which causes an imbalance in the blood's oxygen and carbon dioxide. Due to this fast breathing, the carbon dioxide level is reduced in the blood. This condition of decreased carbon dioxide in the blood is denoted as hypocapnia. Following this, the pH of the blood gets disturbed. Blood becomes alkaline with increased pH. Hyperventilation is a result of many conditions, such as pregnancy, anxiety, pain, tumor trauma, anemia, liver diseases, cardiac issues, shortness of breath, etc.
What Are the Causes of Respiratory Alkalosis?
Central Causes (They Have an Effect Through the Respiratory Center):
- Stroke.
- Head injury.
- Anxiety-hyperventilation syndrome.
- Various drugs like analeptics and salicylate intoxication.
- Endogenous compounds like progesterone during pregnancy and toxins in patients with liver disease.
- Other conditions like fear, stress, etc.
Pulmonary Causes (They Act Through the Intrapulmonary Receptors):
What Are the Effects of Hypocapnia?
The effects of low carbon dioxide levels on the CNS (central nervous system) are:
- Increased neuromuscular irritability.
- Decrease in CBF(cerebral blood flow) with hypocapnia.
- Decrease in intracranial pressure.
- Confusion.
The effects of low carbon dioxide levels on CVS (cardiovascular system) are:
- Cardiac arrhythmias.
- Decreased myocardial contractibility.
- Left side shifting of the hemoglobin oxygen dissociation curve.
- Cerebral vasoconstriction which results in decreased cerebral blood flow.
- Slight fall in plasma level.
What Are the Types of Respiratory Alkalosis?
Respiratory alkalosis can be classified as:
- Acute Respiratory Alkalosis: This occurs at a rapid rate and is a short-term condition. It has a more high pH. The response of the kidneys gets quite slow.
- Chronic Respiratory Alkalosis: This is a long-term condition. The kidneys have more time to decrease the bicarbonate level.
What Are the Symptoms of Respiratory Alkalosis?
The symptoms usually depend on the amount of fall in carbon dioxide. They also vary as per the type of respiratory alkalosis, as in:
- Acute respiratory alkalosis includes lightheadedness, syncope, cramps, confusion, dizziness, fatigue, etc. The other signs are tachypnea (when the respiratory rate is elevated than normal) and hyperpnea (hyperpnea is the increased volume with or without an increase in respiratory rate).
- Chronic respiratory alkalosis: It does not show symptoms as such, as it is asymptomatic.
What Is Puedorespiratory Alkalosis?
Puedorespiratory alkalosis occurs in mechanically ventilated patients. It has low arterial carbon dioxide levels with increased pH due to mechanical ventilation and severe metabolic acidosis due to poor systemic perfusion, for example, in cardiogenic shock during CPR (cardiopulmonary resuscitation). It occurs when mechanical ventilation (hyperventilation) removes the excess amount of alveolar carbon dioxide. When carbon dioxide is exhaled in a larger amount, it causes respiratory alkalosis in the blood and poor systemic perfusion, and cellular ischemia that results in cellular acidosis, hence acidosis of venous blood.
How Is Respiratory Alkalosis Diagnosed?
It is diagnosed by:
- Blood test: Arterial blood gas mechanism (ABG) test: In this test, blood is drawn from the artery that determines the acid-alkaline nature of the blood.
- Serum electrolyte measurement
- Check for the underlying cause.
- Chest X-rays/lung X-rays: They may show the presence of multiple lung alveoli.
- CT scan of the chest.
- Confirmatory Diagnosis: It is given by ABG test PaCO2 levels less than 35 mmHg, and arterial pH tends to be more than 7.45 (that may be near normal in the chronic stage).
- Bicarbonate Level (HCO3): Normal or decreased, which is less than 25 mEq/L.
- Serum Potassium: Decreased.
- Serum Calcium: Decreased.
- Serum Chloride: Increased.
- pH of Urine: Increases (greater than seven).
- A blood test may sometimes reveal anemia(decreased oxygen-carrying capacity of blood).
- A blood culture may show sepsis (by gram-negative bacteria, usually).
- Toxicology screening may reveal poisoning via salicylates.
What Is the Treatment of Respiratory Alkalosis?
- Respiratory alkalosis is not a life-threatening disease. The treatment of respiratory alkalosis is determined by the underlying cause.
- Monitor the patient properly. His respiratory rate, depth, etc. The main cause is hyperventilation, find out its type and whether it is caused due to anxiety, fear, etc.
- The main motive is to increase the level of carbon dioxide in the blood.
- Provide a safe and healthy environment to the patient.
- Slow and deep breathing is advised. Ask the patient to speak in a slow and calm tone.
- Breathing in a paper bag with a mask is suggested. This can compensate for the level of lost CO2.
- Monitoring and graphing of ABGs to be done. Pulse oximetry is also suggested.
- Monitoring of serum potassium levels and compensating them, if required.
- Check the plasma levels.
- Provide medication for pain and sedatives.
- If the levels get too low artificial administration of CO2 is suggested. Re-breathing masks are also provided.
- Respiratory rate and tidal volume are reduced.
- In the case of chronic respiratory cases, underlying causes need to be treated. The primary aim of respiratory alkalosis is to improve airway function. A few medications to treat respiratory alkalosis are:
- In asthmatic patients, bronchodilators are suggested for expanding airways.
- Antibiotics, in case of sepsis.
- Diuretics, in case of increased fluid retention lungs.
- Corticosteroids to reduce inflammation.
- Mechanical ventilation in people with severe respiratory acidosis.
Conclusion:
Respiratory alkalosis is a condition with a decreased level of carbon dioxide, which is less than 35 mmHg and an increased pH of more than 7.45. This can be acute or chronic, depending upon its duration. If treated promptly, this is not a serious condition but can be fatal if left untreated. It can be prevented by promoting a healthy lifestyle, such as living in a healthy environment, weight management avoiding smoking, exercising, etc. It can be treated as per the underlying cause. In case of excessive reduction in CO2 level, artificial supplementation is done. Breathing via a paper bag is also suggested.
