Recognising Respiratory Alkalosis for Student Nurses
Learn how to recognise respiratory alkalosis, assess rapid or deep breathing and connect blood-gas abnormalities with the patient's wider clinical condition.
What is respiratory alkalosis?
Respiratory alkalosis is an acid-base disturbance associated with increased ventilation and reduced carbon dioxide. Blood-gas results may show a raised pH and reduced carbon dioxide, but these findings must always be interpreted alongside the patient's clinical condition.
Breathing increases
Respiratory rate, depth or both may increase enough to remove additional carbon dioxide.
PaCO₂ may fall
Reduced carbon dioxide forms an important part of the respiratory alkalosis pattern.
pH may rise
The blood may become more alkaline when carbon dioxide falls significantly.
What might you notice?
| Finding | Possible presentation | Why it matters |
|---|---|---|
| Tachypnoea | Respiratory rate is increased from the patient's baseline. | Increased ventilation may reduce carbon dioxide. |
| Deep breathing | Breaths appear deeper or more forceful than previously. | Ventilation depends on both respiratory rate and depth. |
| Light-headedness | The patient reports dizziness or feeling faint. | This may accompany significant hyperventilation. |
| Tingling | Tingling may occur around the mouth or in the hands and feet. | Altered sensation can occur during significant respiratory alkalosis. |
| Palpitations | The patient reports awareness of a rapid heartbeat. | This should be assessed within the wider clinical picture. |
| Confusion | New agitation, confusion or reduced concentration. | Neurological change requires further assessment and escalation. |
Ask the most important question: why?
Respiratory alkalosis tells you something about ventilation. It does not by itself tell you what is driving that change.
Why might a patient hyperventilate?
Breathing problems
Hypoxaemia, respiratory disease or other acute respiratory problems may stimulate increased ventilation.
Infection and physiological stress
Fever, significant infection and other acute illnesses may be associated with an increased respiratory rate.
Pain or anxiety
Pain and psychological distress can increase ventilation, but other serious causes should be considered first where clinically relevant.
Context changes the meaning
A rapidly breathing anxious patient with otherwise stable observations presents a different clinical picture from a rapidly breathing patient with chest pain, hypoxaemia, fever, hypotension or reduced consciousness.
Assess the breathing pattern carefully
Measure respiratory rate
Count accurately and compare the result with previous observations.
Observe depth and effort
Determine whether breathing is unusually deep, laboured or associated with increased work of breathing.
Assess oxygenation
Review oxygen saturation against the patient's prescribed target and assess the wider respiratory picture.
Look for associated symptoms
Ask about chest pain, breathlessness, dizziness, tingling, palpitations and pain.
Review blood-gas findings
Note the reported pH, carbon dioxide and other values in the context of the clinical team's interpretation.
Escalate deterioration
Rapid breathing associated with physiological deterioration or concerning symptoms requires appropriate clinical review.
Use ABCDE to find the cause of deterioration
Airway
Confirm airway patency and identify any immediate airway concern.
Breathing
Assess respiratory rate, depth, effort, oxygen saturation, chest movement and ability to speak.
Circulation
Assess pulse, blood pressure, peripheral perfusion and other signs of cardiovascular compromise.
Disability
Assess consciousness and identify dizziness, confusion, agitation or neurological change.
Exposure
Consider temperature, pain, infection, recent illness and other relevant findings.
Escalate
Escalate according to the severity of the patient's overall clinical condition and local procedures.
Understand the broad respiratory pattern
Student nurses do not need to independently provide definitive acid-base interpretation. However, understanding the relationship between ventilation, carbon dioxide and pH helps make blood-gas results more clinically meaningful.
Ventilation increases
The patient moves more air through the lungs than required for current carbon dioxide production.
Carbon dioxide falls
Increased ventilation removes more carbon dioxide from the body.
pH may increase
Reduced carbon dioxide can shift the blood towards alkalinity.
Ventilation → CO₂ → pH
Remembering this relationship helps you understand the broad respiratory alkalosis pattern without losing focus on the patient.
When should respiratory alkalosis increase your concern?
- A rapidly increasing respiratory rate.
- New or worsening breathlessness.
- Rapid breathing associated with chest pain.
- Abnormal oxygen saturation or increasing oxygen requirement.
- Fever or other evidence of significant infection.
- Hypotension or other signs of circulatory deterioration.
- New confusion, agitation or reduced responsiveness.
- A worsening blood-gas abnormality on repeat testing.
- A significant change from the patient's previous respiratory pattern.
Look for changes over time
Mild tachypnoea
Respiratory rate is slightly above the patient's previous baseline.
Breathing increases
Respiratory rate rises further and the patient reports increasing breathlessness and dizziness.
Wider deterioration
The patient becomes increasingly unwell and blood-gas results show a respiratory alkalosis pattern.
The trend is the warning
Progressive tachypnoea combined with new symptoms and worsening physiological observations should prompt reassessment and escalation.
Putting the findings together
Example
A patient admitted with an acute illness has become increasingly tachypnoeic during the shift.
Their respiratory rate has risen considerably from earlier and they now report breathlessness and light-headedness.
They are breathing deeply, their pulse has increased and their latest blood gas is reported as showing low carbon dioxide with a respiratory alkalosis pattern.
The concern is not simply the alkalosis. It is the combined pattern of increasing ventilation, new symptoms and changing physiological observations.
As a student nurse, recognise the change, assess the patient using ABCDE and promptly communicate the respiratory trend and blood-gas findings to the registered and medical team.
Respiratory alkalosis recognition errors to avoid
- Automatically attributing rapid breathing to anxiety.
- Looking at the blood gas without assessing the patient.
- Ignoring the respiratory-rate trend.
- Failing to ask about chest pain or worsening breathlessness.
- Ignoring circulatory or neurological changes.
- Trying to independently diagnose the underlying cause.
- Delaying escalation while attempting detailed blood-gas interpretation.
Describe the breathing change and the wider pattern
Example escalation
“I'm concerned about Ms Jones. Her respiratory rate has increased considerably from earlier and she is now breathing deeply and reporting breathlessness and light-headedness. Her pulse has also increased and the latest blood gas has been reported as showing respiratory alkalosis.”
This communicates the respiratory trend, associated symptoms, physiological changes and blood-gas finding.
Recognise → assess → communicate → escalate
Notice increased ventilation
Identify tachypnoea, deep breathing and a significant change from the patient's baseline.
Find the wider pattern
Use ABCDE and consider oxygenation, circulation, symptoms and blood-gas findings.
Report what has changed
Communicate the respiratory trend, associated deterioration and reported acid-base abnormality.
Build your blood-gas and respiratory assessment skills
Continue developing your ability to connect breathing patterns, blood-gas abnormalities and patient deterioration through the NurseNet Clinical Confidence pathway.
Explore Clinical Confidence →