Metabolic acidosis as an underlying mechanism of respiratory distress in children with severe acute asthma.
OBJECTIVE
1) To alert the clinician that increasing rate and depth of breathing during treatment of acute asthma may be a manifestation of metabolic acidosis with hyperventilation rather than worsening airway obstruction; and 2) to describe the frequency of metabolic acidosis with hyperventilation in children with severe acute asthma admitted to our pediatric intensive care unit.


METHODS
Retrospective medical record review.


METHODS
University-affiliated children's hospital.


METHODS
All patients admitted to the pediatric intensive care unit with a diagnosis of asthma between January 1, 2005, and December 31, 2005.


METHODS
None.


RESULTS
Fifty-three patients with asthma (median age 7.8 yrs, range 0.7-17.9 yrs; 35 [66%] male; 46 [87%] black and 7 [13%] white) were admitted to the pediatric intensive care unit during the study period. Fifteen (28%) patients developed metabolic acidosis with hyperventilation (pH <7.35, Pco2 <35 torr [4.6 kPa], and base excess < or = -7 mmol/L) during their hospital course. Of these, lactic acid was assessed in four patients and was elevated in each; all had hyperglycemia (blood glucose >120 mg/dL [6.7 mmol/L]). Patients who developed metabolic acidosis with hyperventilation received asthma therapy similar to that received by patients who did not develop the disorder. Metabolic acidosis resolved contemporaneously with tapering of beta2-adrenergic agonists and administration of supportive care. All patients survived.


CONCLUSIONS
Metabolic acidosis with hyperventilation manifesting as respiratory distress can occur in children with severe acute asthma. A pathophysiologic rationale exists for the contribution of beta2-adrenergic agents to the development of this acid-base disorder. Failure to recognize metabolic acidosis as the underlying mechanism of respiratory distress may lead to inappropriate intensification of bronchodilator therapy. Supportive care and tapering of beta2-adrenergic agents are recommended to resolve this condition.
Meert
Kathleen L
KL
Children's Hospital of Michigan, Wayne State University School of Medicine, Detroit, MI, USA. kmeert@med.wayne.edu
Clark
Jeff
J
Sarnaik
Ashok P
AP
D000138:Acidosis / Q000175:diagnosis / Q000209:etiology*; D000208:Acute Disease; D000293:Adolescent; D001249:Asthma / Q000150:complications* / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D005260:Female; D006776:Hospitals, Pediatric; D006801:Humans; D006985:Hyperventilation / Q000209:etiology / Q000378:metabolism; D007223:Infant; D015278:Intensive Care Units, Pediatric; D008297:Male; D008485:Medical Audit; D008824:Michigan; D012131:Respiratory Insufficiency / Q000209:etiology* / Q000378:metabolism; D012135:Respiratory Sounds; D012189:Retrospective Studies; D012720:Severity of Illness Index