Respiratory alkalosis resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Rinky Agnes Botleroo, M.B.B.S.

Overview

The first sentence of the overview must contain the name of the disease.

Causes

Life Threatening Causes

Life-threatening causes of Respiratory Alkalosis include

• Sepsis (Cytokine mediated)

Common Causes

• Central Nervous System related causes:
  • Increased Intracranial Pressure
  • Stroke
  • Head injury
  • CNS infection
  • Intracranial hemorrhage
  • Pontine tumors
  • Anxiety Hyperventilation
  • Voluntary Hyperventilation
  • Sepsis(Cytokine mediated)
  • Chronic Liver disease(Toxin mediated)
  • Drugs(Salicylates, progesterone)
  • Pain
• Hypoxemic causes: Hypoxic stimulation leads to hyperventilation.
• Pulmonary Causes:
  • Pneumonia
  • Asthma
  • Pulmonary oedema
  • Pulmonary thromboembolism
• Extrinsic Causes(deliberate or iatrogenic):
  • Excessive minute ventilation during mechanical ventilation

Diagnosis

Shown below is an algorithm summarizing the diagnosis of Respiratory Alkalosis:

Patient with Acute Respiratory Alkalosis

Take complete history

Ask the following questions regarding CNS manifestations ❑If they felt dizzy or confused recently? Light-headedness and Confusion due to reduced cerebral blood flow ❑If they felt numbness or tingling sensation on peripheral parts of the body? Acral 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 seizues

Ask the following questions regarding Cardiovascular manifestations ❑Ask if they felt any chest discomfort or pain? Chest pain due to vasoconstriction ❑If they felt their heart was racing? Ask about cardiac Arrythmia

Ask the following questions regarding Metabolic effects ❑Ask if they have experienced perioral tingling sensations ❑Tetany ❑Ask about any symptoms of mild hyponatremia, hypokalemia, and hypophosphatemia

Do complete physical examination

Vital signs ❑Decreased blood pressure(hypotension) due to hypoxemia ❑Increased heart rate due to fever, anxiety ❑Increased temperature due to infection or sepsis ❑Tachypnea due to Arrhythmias, hypoxemia, pulmonary disease ❑Orthostatic changes due to reduced plasma volume

Examination of respiratory system ❑Inspiratory crackles if patient has Pulmonary edema ❑Inspiratory ronchi and crackles in patient with Pulmonary fibrosis ❑ Tachypnea, pulmonary rub in Pulmonary embolism ❑Prolonged expiratory wheezing in patient with Asthma

Examination of Cardiovascular System ❑Irregular rhythm may be seen ❑palpable P2, right ventricular heave may be seen if patient has Pulmonary hypertension

Examination of Abdomen ❑Ascites in Liver disease ❑Gravid uterus in pregnany woman

Examination of the Extremities ❑Cyanosis due to hypoxemia

Examination of Central Nervous System ❑Tremor, paresthesias ❑ Muscle weakness Hypokalemia, hypophosphatemia ❑Chvostek’s and Trousseau’s signs due to Low ionized Ca2+

Do following tests

Serum Chemistry ❑Persistent hyponatremia, hypokalemia, hypophosphatemia, and low ionized Ca2+ ❑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 ❑In acute respiratory alkalosis, serum [HCO3−] is around 20 mEq/L, because the secondary response to hypocapnia of 20 mmHg is a decrease of 4 mEq/L from normal [[[HCO3]]−] of 24 mEq/L ❑Serum [[[HCO3]]−] from normal level of 24 mEq/L drops to 16 mEq/L in chronic respiratory alkalosis for the same hypocapnia of 20 mmHg.

Do Chest X-ray

Do Blood cultures

Treatment

1. Respiratory alkalosis is not self-limiting.
2. 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

Treatment options ❑Rebreathing into a paper or plastic bag ❑mild sedation ❑Reassurance

If patient is Hypoxic

Treatment options ❑Give O2

Respiratory Alkalosis

Salicylates overdose

Treatment options ❑Urinary alkalinization ❑Forced diuresis ❑Dialysis

If patient has Hyperthyroidism

Treatment options ❑β-Blockers ❑Antithyroid medications

If patient has Asthma

Treatment options ❑Bronchodilators ❑Corticosteroids

If patient has Pneumonia

Treatment options ❑Antibiotics

If patient has Pulmonary oedema

Treatment options ❑Diuretics ❑Treatment and improvement in CHF

If patient has Pulmonary embolism

Treatment options ❑Give O2 ❑Anticoagulation

If patient has history of going to high altitude, climbing

Treatment options ❑Give O2 ❑Acetazolamide

Mechanical ventilation

Treatment options ❑Reduce Ventilatory rate and tidal volume ❑ Increase dead space ❑mild sedation without skeletal muscle paralysis

Do's

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Don'ts

• The content in this section is in bullet points.