Respiratory Alkalosis Nursing Management and Interventions

Respiratory alkalosis comes from blowing off too much CO2, usually through hyperventilation, and the fastest cause you will see is anxiety. The pH climbs as PaCO2 falls. Calm the patient, slow the breathing, find the trigger, and watch for the arrhythmias and tetany that follow.

What is Respiratory Alkalosis?

Respiratory alkalosis is an acid-base imbalance marked by decreased partial pressure of arterial carbon dioxide (less than 35 mm Hg) and increased blood pH (greater than 7.45), due to alveolar hyperventilation. Uncomplicated respiratory alkalosis lowers hydrogen ion concentration, which raises blood pH.

Causes

Pulmonary causes include severe hypoxemia, pneumonia, interstitial lung disease, pulmonary vascular disease, and acute asthma. Nonpulmonary causes include anxiety, fever, aspirin toxicity, metabolic acidosis, central nervous system disease, and pregnancy.

Complications

Watch for cardiac arrhythmias and seizures.

Signs and Symptoms

The cardinal sign is deep rapid breathing (40+ bpm). Expect CNS and neuromuscular disturbances: lightheadedness, agitation, circumoral and peripheral paresthesias, carpopedal spasms, twitching, and muscle weakness. A positive Chvostek's sign, nausea and vomiting, and muscle twitching round out the picture.

Assessment

Circulation: a history or presence of anemia and palpitations; hypotension, tachycardia, and irregular pulse or dysrhythmias.

Ego integrity: extreme anxiety, the most common cause of hyperventilation.

Food and fluid: dry mouth, nausea, and vomiting; abdominal distension from an elevated diaphragm (ascites, pregnancy) with vomiting.

Neurosensory: headache and tinnitus; numbness and tingling of the face, hands, and toes with circumoral and generalized paresthesia; lightheadedness, syncope, vertigo, and blurred vision; confusion, restlessness, obtunded responses, and coma; hyperactive reflexes, positive Chvostek's sign, tetany, and seizures; heightened sensitivity to environmental noise and activity; muscle weakness and unsteady gait.

Pain and discomfort: muscle spasms or cramps, epigastric pain, and precordial pain (tightness).

Respiration: dyspnea, a history of asthma or pulmonary fibrosis, or recent move or visit to high altitude; tachypnea with rapid, shallow breathing and hyperventilation (often 40 or more respirations per minute); intermittent periods of apnea.

Safety: fever.

Teaching and learning: use of salicylates or salicylate overdose, catecholamines, or theophylline. Care may require a change in the treatment or therapy of the underlying disease process or condition.

Diagnostic Studies

Confirm the diagnosis with arterial blood gas (ABG) analysis showing PaCO2 less than 35 mmHg and pH elevated in proportion to the fall in PaCO2 (acute) or failing toward normal (chronic). ABG studies reveal abnormal values: pH above 7.45 and partial pressure of carbon dioxide below 35 mmHg.

Arterial pH is greater than 7.45 (may be near normal in the chronic stage). Bicarbonate (HCO3) is normal or decreased, less than 25 mEq/L (compensatory mechanism). PaCO2 is decreased, less than 35 mm Hg (primary). Serum potassium is decreased, serum chloride is increased, and serum calcium is decreased. Urine pH is increased, greater than 7.0.

Run screening tests to find the cause: CBC may reveal severe anemia (decreasing oxygen-carrying capacity); blood cultures may identify sepsis (usually Gram-negative); blood alcohol may be markedly elevated (acute alcoholic intoxication); a toxicology screen may reveal early salicylate poisoning; and chest x-ray or lung scan may reveal multiple pulmonary emboli.

Nursing Priorities

Achieve homeostasis, prevent or minimize complications, and provide information about the condition, prognosis, and treatment needs as appropriate.

Discharge Goals

Restore physiologic balance, keep the patient free of complications, confirm the condition, prognosis, and treatment needs are understood, and put a plan in place to meet needs after discharge.

Care Setting

Respiratory alkalosis does not occur in isolation. It is a complication of a broader problem and usually requires inpatient care in a medical-surgical or subacute unit.

Related Concerns

Use plans of care specific to the predisposing factors: anemias (iron deficiency, pernicious, aplastic, hemolytic), cirrhosis of the liver, craniocerebral trauma, hyperthyroidism, fluid and electrolyte imbalances, chronic heart failure, microbial pneumonia, sepsis or septicemia, and mechanical ventilatory assistance. Other concerns include metabolic acidosis and metabolic alkalosis.

Nursing Diagnosis

Possible nursing diagnoses include impaired gas exchange, ineffective breathing pattern, ineffective tissue perfusion, acute confusion, and risk for injury.

Nursing Interventions and Considerations

Stay alert for changes in neurologic, neuromuscular, or cardiovascular function. Institute safety measures for the patient with vertigo or the unconscious patient. Encourage the anxious patient to verbalize fears, and administer sedation as ordered to relax the patient. Keep the patient warm and dry. Coach the patient to take deep, slow breaths or breathe into a brown paper bag to inspire CO2. Monitor vital signs. Monitor ABGs, primarily PaCO2; a value less than 35 mmHg indicates too little CO2 (carbonic acid).