JW, Matzke GR. Acid–Base Disorders. In: DiPiro, JT, Talbert
RL, Yee GC, Matzke GR, Wells BG, Posey LM. Pharmacotherapy: A Pathophysiologic
Approach. 8th ed. http://accesspharmacy.com/content.aspx?aid=7984321.
Accessed August 8, 2012.
- Acid–base disorder characterized by primary decrease
in PaCO2 that leads to elevation in pH.
- Increases in neurochemical stimulation via central or
- Physical increases in ventilation via voluntary or artificial
means (e.g., mechanical ventilation)
- Paco2 decreases when
ventilatory CO2 excretion exceeds metabolic CO2 production,
usually because of hyperventilation.
- Earliest compensatory response
is to chemically buffer excess bicarbonate by releasing hydrogen ions
from intracellular proteins, phosphates, and hemoglobin.
- Kidneys increase bicarbonate elimination with prolonged respiratory
alkalosis (>6 hours).
- Usually asymptomatic if condition chronic and mild.
- Decreased cerebral blood flow may result in:
- Decreased intellectual functioning
- Nausea and vomiting can occur, probably due to cerebral hypoxia.
- Cardiac arrhythmias
Means of Confirmation
- Primary tools for determining cause of acid–base
disorders and designing therapy:
- Blood gases
- Serum electrolytes
- Medical history
- Clinical condition
- Metabolic panel
- Serum chloride usually
- Serum potassium, phosphorus, and ionized calcium usually decreased.
- Arterial blood gases (ABG) measured to determine oxygenation
and acid–base status.
- Correction of acid–base disorder
- Treatment often unnecessary because most patients have
few symptoms and only mild pH alterations (i.e., pH <7.50).
- Direct measures (e.g., treatment of pain, hypovolemia,
fever, infection, or salicylate overdose) can be effective.
- Rebreathing device (e.g., paper bag) can help control hyperventilation
in patients with anxiety/hyperventilation syndrome.
- Adjust ventilator if respiratory alkalosis associated with
- Initiate oxygen therapy with severe hypoxemia.
- ABG measurements primary tools for evaluation of therapeutic
- Monitor closely to ensure resolution of
simple acid–base disorders without deterioration to mixed disorders
due to compensatory mechanisms.
- Monitor metabolic panel.
- Resolution of underlying disorder determines prognosis.