Progesterone direct effect on respiratory neurons in pregnancy
Pulmonary mechanoreceptor activation
J receptors activated by pulmonary edema and inflammation
Stretch receptors in pneumonia and ILD
Iatrogenic cause
Excessive mechanical ventilation settings
High tidal volume or respiratory rate
Physiologic consequences
Alkalemia effects
Cerebral vasoconstriction causing reduced CBF 2% per mmHg PaCO2 drop
Coronary vasoconstriction risk
Shift in oxygen-hemoglobin dissociation curve leftward
Electrolyte shifts
Hypokalemia from K+ shift into cells
Ionized hypocalcemia from increased protein binding
Hypophosphatemia from alkalemia-driven cellular uptake
Compensation mechanism
Acute: bicarbonate consumed by tissue buffering
Chronic: renal bicarbonate excretion over 2 to 3 days
Maximum chronic compensation limits HCO3 to approximately 12 to 18 mmol/L
Therapeutic Considerations
Treatment principles
Treat the underlying cause — not the alkalosis itself
Respiratory alkalosis is rarely the primary therapeutic target
Correction of pH without addressing cause is inadequate
Avoid dangerous maneuvers
Paper bag rebreathing contraindicated when organic cause not excluded
Intubation in salicylate toxicity removes compensatory alkalosis
Electrolyte monitoring and correction
Potassium and calcium most clinically relevant
Correction may improve symptoms even before PaCO2 normalizes
Prognosis and outcome
Hyperventilation syndrome
Excellent prognosis with behavioral therapy
Recurrence common without psychiatric follow-up
Critically ill patients
Prognosis determined by underlying cause
Persistence of respiratory alkalosis in sepsis associated with higher mortality
Evidence base
No randomized trials exist for isolated respiratory alkalosis treatment
Management is expert consensus and underlying disease guideline driven
Class IIb evidence for most specific interventions
Patient Discharge Instructions
copy discharge instructions
Respiratory alkalosis home care
Rest and avoid strenuous activity until follow-up
Avoid aspirin and salicylate-containing medications unless directed by your doctor
If symptoms were due to anxiety or panic, slow deep breathing exercises at home
Take all prescribed medications as directed
Warning signs to return to ER
Trouble breathing or very fast breathing returning
Chest pain or palpitations
Numbness or tingling in face or hands returning and not resolving
Muscle cramps or spasms in hands or feet
Confusion, difficulty speaking, or weakness on one side of body
Fainting or near-fainting
Fever above 38.5 degrees Celsius
Leg swelling or pain in one leg
Ringing in ears especially if you have taken aspirin recently
Follow-up instructions
Primary care physician within 2 to 3 days
Tell your doctor what medications and supplements you are taking
If panic attacks or anxiety was the cause, speak with your doctor about referral
Breathing technique for hyperventilation syndrome
Breathe in slowly through nose for 4 seconds
Hold breath for 2 seconds
Breathe out slowly through mouth for 6 seconds
Repeat 10 times during an episode
References
Guidelines and key sources
Acid-base disorder guidelines
American Thoracic Society statements on arterial blood gas interpretation
ACEP Clinical Policies on arterial blood gas use in undifferentiated dyspnea
Surviving Sepsis Campaign 2021 guidelines — early recognition and management
PE and DVT guidelines
AHA 2019 guidelines on acute PE management
Wells PE clinical decision tool validation studies
ACEP Level B recommendation for CT pulmonary angiography in suspected PE
Toxicology references
American College of Medical Toxicology salicylate toxicity management guidelines
Extracorporeal Treatment in Poisoning workgroup recommendations for hemodialysis in salicylate toxicity
Evidence summaries
Studies correlating degree of hypocapnia with ICU mortality
RCT evidence for sodium bicarbonate in salicylate urinary alkalinization
Review of physiologic respiratory alkalosis in pregnancy
Coding standards
ICD-10 E87.3 alkalosis
ICD-10 J96.0 acute respiratory failure
SNOMED CT 1207005 respiratory alkalosis disorder
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.