From the Guidelines
The treatment of respiratory alkalosis caused by a stroke should focus on addressing the underlying neurological injury while managing the acid-base disturbance, with the most recent and highest quality study 1 emphasizing the importance of monitoring oxygen saturation and treating hypoxemia. The goal is to ensure adequate oxygenation and ventilation, as respiratory alkalosis in stroke patients often results from hyperventilation due to brain stem involvement or anxiety. If the patient is on mechanical ventilation, adjust ventilator settings to reduce minute ventilation by decreasing respiratory rate or tidal volume. For conscious patients with voluntary hyperventilation, reassurance and coaching on breathing techniques may help normalize breathing patterns. In severe cases, sedation with medications like benzodiazepines (such as lorazepam 0.5-1mg IV) may be necessary to control hyperventilation. Treat the underlying stroke according to standard protocols, including appropriate reperfusion therapy if indicated, blood pressure management, and prevention of secondary injury, as outlined in guidelines such as those from the American Heart Association 1. Avoid rapid correction of alkalosis as this may cause cerebral vasoconstriction and worsen neurological outcomes. Monitor arterial blood gases regularly to track pH and PCO2 levels, and provide supplemental oxygen to hypoxemic patients, as recommended by studies 1. Respiratory alkalosis in stroke patients occurs because brain injury can disrupt respiratory control centers, leading to hyperventilation and subsequent decrease in carbon dioxide levels, which raises blood pH. Addressing both the respiratory abnormality and the underlying stroke is essential for optimal patient outcomes, prioritizing morbidity, mortality, and quality of life. Some key considerations include:
- Ensuring adequate oxygenation and ventilation
- Monitoring and managing blood pressure
- Preventing secondary injury
- Providing appropriate reperfusion therapy if indicated
- Avoiding rapid correction of alkalosis
- Monitoring arterial blood gases regularly.
From the Research
Treatment of Respiratory Alkalosis Caused by Stroke
- Respiratory alkalosis is a rare but severe complication of acute ischemic stroke (AIS) that results from hyperventilation due to the effect of stroke on the respiratory center 2.
- The treatment of respiratory alkalosis caused by stroke involves correcting the underlying etiology, which in this case is the stroke itself 3.
- Mechanical ventilation has been used to resolve severe respiratory alkalosis in patients with AIS 2.
- Maintaining acid-base balance in the acute stage of the stroke with proper dehydration therapy and oxygen administration is also important 4.
- The extent of motor impairment is positively associated with blood gas abnormalities, including respiratory alkalosis, and initial findings of respiratory alkalosis can predict poor motor recovery during the follow-up period 5.
Key Considerations
- Respiratory alkalosis can produce multiple metabolic abnormalities, including changes in potassium, phosphate, and calcium levels, as well as the development of a mild lactic acidosis 3.
- Renal handling of ions is also affected in respiratory alkalosis, and correction of the underlying etiology is crucial for survival and recovery 2, 3.
- Respiratory alkalosis can be acute or chronic, and metabolic compensation initially consists of cellular uptake of HCO3- and buffering by intracellular phosphates and proteins 6.