Internal Medicine

P1: SBT

0521779407-02 CUNY1086/Karliner 0 521 77940 7 June 7, 2007 19:18

56 Acute Respiratory Acidosis Acute Respiratory Alkalosis

■Causes of Acute Respiratory Acidosis

➣Airway obstruction – laryngospasm, bronchospasm (severe

asthma), obstructive sleep apnea

➣Circulatory catastrophes – cardiac arrest, severe pulmonary

edema, massive pulmonary embolus

Note: In severe circulatory failure or cardiac arrest, arterial

blood may show a low PCO2 even though venous blood PCO2 is

high (termed “pseudorespiratory alkalosis”) due to preservation

of ventilation in the face of a marked reduction in pulmonary

perfusion. Should be treated as respiratory acidosis.

➣CNS depression – anesthesia, sedatives, cerebral trauma

➣Neuromuscular impairment – Guillain-Barre, myasthenic crisis, ́

cervical cordotomy, drugs and toxins

➣Ventilatory restriction – pneumothorax, flail chest, adult respira-

tory distress syndrome (ARDS)

➣Iatrogenic mishaps – anesthesia equipment failures

management

■Reestablish airway.

■Relieve bronchospasm.

■Ensure adequate oxygen delivery.

■Assisted ventilation as needed

■Use bicarbonate only when other approaches fail to improve venti-

lation, as a temporizing measure to increase pH.

specific therapy

n/a

follow-up

■Correct underlying cause.

complications and prognosis

■Excellent if cause can be corrected, otherwise poor with limited sur-

vival, death, if process not rapidly reversed

Acute Respiratory Alkalosis..............................

F. JOHN GENNARI, MD

history & physical

■Air hunger

■Numbness (circumoral), tingling in extremities