👤 By the CinnaRN Clinical Content Team🕐 Updated 2026-08-23🏷️ Physiological Adaptation🔖 Free to read, print, and share
Also known as: low CO2 · hyperventilation · high pH from lungs · over-breathing
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Use this quick-reference guide to spot, treat, and prevent Respiratory Alkalosis on the NCLEX. Keep it handy during review and on exam day!
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📒 The 1-minute cheat sheet
🧪 Labs
pH > 7.45, PaCO₂ < 35
Blowing off too much CO₂
🩺 Signs
Lightheaded, tingling fingers
Tetany, dizzy, palpitations
✅ Do
Slow breathing, reassure pt
Rebreathe (paper bag) if anxiety
⚠️ Causes
Anxiety, panic, fear
Fever, pain, PE, high altitude
📚 Respiratory Alkalosis — full study notes
The cheat sheet above is your quick recall card. These notes go deeper — what it is, what to do first, what must be reported, and what to teach.
Respiratory alkalosis is a high blood pH (above 7.45) caused by excessive exhalation of carbon dioxide from hyperventilation, reflected in a low PaCO2 (below 35). Common causes include anxiety/panic, pain, fever, hypoxia, salicylate (aspirin) overdose, and over-aggressive mechanical ventilation. Because CO2 is an acid, blowing off too much CO2 raises pH. Anxiety-driven hyperventilation is the classic and most common cause.
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Key points
Understand these first
ABG pattern: high pH (over 7.45) with low PaCO2 (under 35 mmHg); the low CO2 drives the disorder.
Hyperventilation is the cause, so the client breathes rapidly and deeply.
Increased neuromuscular excitability causes tingling/numbness of fingers, toes, and around the mouth, plus muscle cramps and spasms.
Lightheadedness, dizziness, and a feeling of panic or chest tightness are common.
Severe alkalosis can cause carpopedal spasm, tetany, and seizures.
It is usually acute; renal compensation (excreting bicarbonate) takes hours to days and is limited.
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Nursing priorities
What to do, in order
Help the client slow and control their breathing using calm coaching and reassurance.
Identify and treat the underlying cause (relieve anxiety, treat pain, fever, hypoxia, or salicylate toxicity).
For anxiety-driven hyperventilation, encourage slow breathing or breathing into cupped hands/paper bag if appropriate to rebreathe CO2.
Monitor ABGs, oxygen saturation, and for tetany or paresthesias.
Provide oxygen and address hypoxia if that is the trigger for hyperventilation.
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Red flags — report now
Escalate immediately
Hyperventilation that does not resolve, or with hypoxia - look for a serious cause (PE, sepsis, salicylate overdose) and notify provider.
Tetany, carpopedal spasm, or seizures - report immediately.
In a salicylate overdose, respiratory alkalosis may progress to mixed acid-base disturbance - escalate.
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Labs & values
Numbers to know
pH normal 7.35-7.45; respiratory alkalosis pH greater than 7.45
PaCO2 normal 35-45 mmHg; decreased (under 35) in respiratory alkalosis
HCO3 normal 22-26 mEq/L; decreased with renal compensation in chronic cases
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Patient teaching
What patients must know
Practice slow, controlled breathing and relaxation techniques for anxiety.
Recognize early signs of hyperventilation, such as tingling and dizziness.
Seek care for sudden shortness of breath, chest pain, or breathing fast with no clear cause.
❓ Respiratory Alkalosis: NCLEX FAQs
What are the priority nursing interventions for Respiratory Alkalosis?
Help the client slow and control their breathing using calm coaching and reassurance. Identify and treat the underlying cause (relieve anxiety, treat pain, fever, hypoxia, or salicylate toxicity). For anxiety-driven hyperventilation, encourage slow breathing or breathing into cupped hands/paper bag if appropriate to rebreathe CO2. Monitor ABGs, oxygen saturation, and for tetany or paresthesias.
What are the warning signs of Respiratory Alkalosis a nurse must report?
Hyperventilation that does not resolve, or with hypoxia - look for a serious cause (PE, sepsis, salicylate overdose) and notify provider. Tetany, carpopedal spasm, or seizures - report immediately. In a salicylate overdose, respiratory alkalosis may progress to mixed acid-base disturbance - escalate.
What do I need to know about Respiratory Alkalosis for the NCLEX?
ABG pattern: high pH (over 7.45) with low PaCO2 (under 35 mmHg); the low CO2 drives the disorder. Hyperventilation is the cause, so the client breathes rapidly and deeply. Increased neuromuscular excitability causes tingling/numbness of fingers, toes, and around the mouth, plus muscle cramps and spasms. Lightheadedness, dizziness, and a feeling of panic or chest tightness are common.
What patient teaching is important for Respiratory Alkalosis?
Practice slow, controlled breathing and relaxation techniques for anxiety. Recognize early signs of hyperventilation, such as tingling and dizziness. Seek care for sudden shortness of breath, chest pain, or breathing fast with no clear cause.
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Quick Tip
ABG pattern: high pH (over 7.45) with low PaCO2 (under 35 mmHg); the low CO2 drives the disorder.