Respiratory Alkalosis is a common acid–base imbalance that occurs when the body loses too much carbon dioxide (CO₂) through rapid or deep breathing. CO₂ plays a crucial role in maintaining blood pH, and when its levels drop too quickly, the blood becomes too alkaline. This creates a physiological imbalance that can affect multiple organs, especially the brain, muscles, and cardiovascular system.
Although Respiratory Alkalosis is often temporary, it can also indicate underlying conditions such as anxiety disorders, lung disease, infections, or metabolic disturbances. Understanding its causes, symptoms, and treatment is essential for timely management, especially in hospital settings or during respiratory emergencies.
This detailed guide explores everything you need to know about Respiratory Alkalosis, including its mechanisms, risk factors, diagnosis, treatment options, and commonly asked questions.
What is Respiratory Alkalosis?
Respiratory Alkalosis occurs when excessive exhalation of carbon dioxide (hyperventilation) leads to a reduction in the partial pressure of CO₂ (PaCO₂). Carbon dioxide helps regulate acidity levels in the blood. When CO₂ levels fall, the blood becomes more alkaline, causing the pH level to rise above 7.45.
Normal Blood Values
pH: 7.35 – 7.45
PaCO₂: 35 – 45 mmHg
HCO₃⁻: 22 – 26 mEq/L
In Respiratory Alkalosis:
pH increases (>7.45)
PaCO₂ decreases (<35 mmHg)
The kidneys may compensate by excreting bicarbonate, but this takes time, making acute cases clinically significant.
Causes of Respiratory Alkalosis
1. Anxiety and Panic Disorders
Emotional stress, fear, and panic attacks are the most common triggers, causing rapid breathing.
2. Hypoxemia
Low blood oxygen stimulates faster breathing.
Common causes:
High altitude
Lung diseases such as pneumonia or pulmonary embolism
3. Fever and Infections
High fever increases metabolic demand and respiratory rate.
4. Pain or Trauma
Severe pain, injuries, or trauma can disrupt normal breathing patterns.
5. Medications
Drugs that stimulate the brain’s respiratory centre:
Aspirin toxicity
Progesterone
Respiratory stimulants
6. Central Nervous System Disorders
These conditions alter respiratory control:
7. Mechanical Overventilation
Incorrect ventilator settings can cause excessive CO₂ removal.
8. Liver Diseases
Severe liver failure may lead to hyperventilation.
Symptoms of Respiratory Alkalosis
Symptoms may be mild or severe depending on how quickly CO₂ levels drop.
Neurological Symptoms
Restlessness followed by lethargy
Confusion
Light-headedness
Irritability
Tremors
Decreased level of consciousness
Cardiac Symptoms
Dysrhythmias
Respiratory Symptoms
Compensatory hypoventilation (in chronic cases)
Gastrointestinal Symptoms
Metabolic Symptoms
Muscle cramps
Sudden alkalosis may cause fainting or seizures due to reduced cerebral blood flow.
Pathophysiology
Rapid breathing removes too much CO₂, reducing carbonic acid and raising blood pH. Higher pH affects many systems:
Increased binding of calcium → tingling, muscle cramps
Cerebral vasoconstriction → dizziness
Altered potassium balance → hypokalemia
Chronic cases allow time for kidney compensation by excreting bicarbonate.
Diagnosis of Respiratory Alkalosis
1. Arterial Blood Gas (ABG)
The most accurate test.
Findings:
High pH
Low PaCO₂
Normal/low HCO₃⁻
2. Electrolyte Test
Often shows low potassium and low ionised calcium.
3. Chest X-ray
Checks for lung infections or structural issues.
4. ECG
Evaluates arrhythmias.
5. Pulse Oximetry
Assesses oxygen levels.
6. Toxicology Screening
Important when aspirin toxicity is suspected.
Treatment of Respiratory Alkalosis
1. Breathing Techniques
Useful for anxiety-induced cases:
Slow breathing
Pursed-lip breathing
Guided relaxation
2. Treat Hypoxemia
Oxygen therapy
Treatment of lung diseases
Managing anemia
3. Control Fever or Infection
Using antipyretics or antibiotics.
4. Manage Pain
Proper pain relief helps prevent hyperventilation.
5. Adjust Ventilator Settings
In ICU patients, ventilator rate and volume must be corrected.
6. Address Salicylate Poisoning
Activated charcoal
Fluids
Dialysis in severe cases
7. Manage CNS Conditions
Treating infections, inflammation, or lesions regulates breathing.
8. Electrolyte Replacement
Correcting potassium and calcium levels restores neuromuscular and cardiac stability.
Complications
Untreated Respiratory Alkalosis may lead to:
Reduced cerebral blood flow
Loss of consciousness
Chronic cases may overwhelm compensatory mechanisms leading to severe imbalance.
Prevention Tips
Practice slow breathing during stress
Avoid high doses of aspirin
Manage chronic lung diseases properly
Stay hydrated
Seek early treatment for fever and infections
Use ventilators only under expert supervision
Frequently Asked Questions (FAQ)
1. What is the most common cause of Respiratory Alkalosis?
Hyperventilation due to anxiety or panic is the leading cause.
2. Can it develop quickly?
Yes, it can appear within minutes during rapid breathing episodes.
3. Is Respiratory Alkalosis dangerous?
Mild cases are manageable, but severe untreated cases can lead to seizures and arrhythmias.
4. How is it diagnosed?
Primarily through an Arterial Blood Gas (ABG) test.
5. Does it resolve naturally?
Stress-related cases may resolve once breathing normalises.
6. Can children get it?
Yes, due to fever, anxiety, infections, or ventilator-related issues.
7. Is it related to high altitudes?
Yes. Low oxygen levels at high altitudes can cause hyperventilation leading to alkalosis.
8. How is it different from Metabolic Alkalosis?
Respiratory Alkalosis is caused by CO₂ loss, whereas Metabolic Alkalosis results from high bicarbonate or acid loss.
9. Can dehydration cause it?
Indirectly, as dehydration-associated fever or anxiety may trigger rapid breathing.
10. What should you do during hyperventilation?
Practise slow, controlled breathing and seek help if symptoms persist.
Respiratory Alkalosis is a significant but often reversible condition caused by excessive CO₂ loss through hyperventilation. It may arise from stress, lung disease, fever, or metabolic conditions. Early identification and treatment are essential to avoid complications such as arrhythmias, fainting, or seizures. Proper diagnosis through ABG testing and management of the underlying cause ensures restoration of normal acid–base balance and overall health.
#BhaloTheko
Disclaimer:
No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.
Sparsh Doctor List
