Respiratory alkalosis resident survival guide
|Respiratory alkalosis Resident Survival Guide Microchapters|
Editor-In-Chief: C. Michael Gibson, M.S., M.D. ; Associate Editor(s)-in-Chief: Rinky Agnes Botleroo, M.B.B.S.
Synonyms and keywords: Approach to respiratory alkalosis, Respiratory alkalosis management, Respiratory alkalosis Workup
The normal physiological pH of blood is 7.35 to 7.45. An increase above this range is known as alkalosis. Respiratory alkalosis is a state where the body’s pH is more than 7.45 secondary to some respiratory or pulmonary cause.Respiratory alkalosis is characterized by the presence of low pCO2and high pH (>7.40). Respiratory alkalosis occurs when a person breathes too quickly or too deep and carbon dioxide levels drop too low. This causes the pH of the blood to increase and become too alkaline. It is also known as the primary hypocapnia in which patients usually present with hyperventilation. The resultant alkalinization of body fluids is balanced by a decrease in serum [HCO3-]. Secondary hypocapnia should be differentiated from primary hypocapnia, as the former occurs in response to metabolic acidosis. When respiratory alkalosis develops, a decrease in serum [HCO3-] occurs within a few minutes. This is due to non-bicarbonate buffering as well as H+ release from tissues. This buffering from various sources persists for several hours, and the resultant acid-base disturbance is called acute respiratory alkalosis. During acute respiratory alkalosis, the H+ secretion in both proximal tubule and cortical collecting duct is suppressed. When alkalemia persists, renal compensation starts with a decrease in both H+ secretion and basolateral exit of [HCO3-]in the proximal tubule. This lowers more serum [HCO3-], due to which the pH is maintained close to normal. The complete renal compensation takes 2–3 days to occur, and when a new steady state is established, it is called chronic respiratory alkalosis.
Life-threatening causes of Respiratory Alkalosis include:
- Central Nervous System related causes:
- Hypoxemic causes: Hypoxic stimulation leads to hyperventilation.
- Pulmonary Causes:
- Extrinsic Causes(deliberate or iatrogenic):
|Patient with Acute Respiratory Alkalosis|
|Take complete history|
Ask the following questions regarding CNS manifestations
paresthesia due to reduced blood flow to the skin
❑ Ask if they had experienced tremor of the hand when the wrist is extended, sometimes said to resemble a bird flapping its wings to check asterexis
❑ If there is any history of loss of consciousness
❑ Ask about any event of seizures
|Do complete physical examination|
Examination of Cardiovascular System
❑ Irregular rhythm may be seen
❑ Palpable P2, right ventricular heave may be seen if patient has pulmonary hypertension
|Do following tests|
❑ Persistent hyponatremia, hypokalemia, hypophosphatemia, and low ionizedCa2+
❑Increased WBC if there is any infection
❑ Decreased hemoglobin if there is anemia
❑ Increased Hematocrit which is suggestive of exposure to high altitude
❑ Abnormal liver function tests in liver disease
❑ Increased T3 and T4 and low TSH in a patient of hyperthyroidism
❑ Positive urine β-human chorionic hormone if patient is pregnant
❑ When both respiratory alkalosis and high Anion gap metabolic acidosis are present—suspect salicylate intake
Do Arterial Blood Gas (ABG)
❑ Low pCO2, low serum [HCO3−], high pH
Do Chest X-ray
- Respiratory alkalosis is not self-limiting.
- Correction of the primary disorder of the respiratory alkalosis is needed
- Shown below is an algorithm summarizing the treatment of Respiratory Alkalosis:
|If patient comes with Anxiety or hyperventilation syndromes|
❑ Breathing into a paper or plastic bag
❑ Mild sedation
❑ To view treatment of panic attack click here
|If patient is Hypoxic|
❑ Give O2
|Respiratory Alkalosis||Salicylates overdose|
❑ Urinary alkalinization
❑ Forced diuresis
|If patient has Hyperthyroidism|
|If patient has Asthma|
|If patient has Pneumonia|
|If patient has pulmonary oedema|
|If patient has pulmonary embolism|
|If patient has history of going to high altitude climbing|
❑ Reduce ventilatory rate and tidal volume
❑ Increase dead space
❑ Mild sedation without skeletal muscle paralysis
- Patient may experience faster and deeper breathing, physician should provide reassurance and empathy which can help to get patient's breathing under control.
- Physicians should look for the underlying cause and its severity.
- A patient who suffers from regular respiratory alkalosis can seek help from a therapist and can learn breathing exercises, meditation, and regular exercise.
- Patients should not hesitate to seek help from professionals in case of recurrence of respiratory alkalosis.
- "Respiratory Alkalosis - StatPearls - NCBI Bookshelf".
- Hopkins E, Sanvictores T, Sharma S. PMID 29939584. Missing or empty
- Hasan, Ashfaq (2009). "Respiratory Alkalosis": 207–212. doi:10.1007/978-1-84800-334-7_9.
- Reddi, Alluru S. (2018). "Respiratory Alkalosis": 441–448. doi:10.1007/978-3-319-60167-0_33.
- "Respiratory Alkalosis: Symptoms, Treatments, and Prevention".