title: Mechanism of lactic acidosis in children with acute severe asthma.
abstract: OBJECTIVE
  Hyperlactatemia and lactic acidosis are common in adults with acute severe asthma however only a few cases have been reported in children. Type A lactic acidosis is associated with impaired oxygen delivery; type B occurs in the presence of normal oxygen delivery and has been described to occur with excessive adrenergic stimulation. Type A and B lactic acidosis can be distinguished by the blood lactate/pyruvate ratio. Our objectives are to 1) investigate the incidence of hyperlactatemia and lactic acidosis in children with acute severe asthma, and 2) determine whether lactate elevation is type A or B.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  University-affiliated tertiary care children's hospital.
  
  
  METHODS
  All children (n = 105) with acute severe asthma admitted to the pediatric intensive care unit between May 1, 2008 and November 30, 2009 were included.
  
  
  METHODS
  Blood lactate concentration was measured on a blood gas analyzer for all blood gas assessments obtained for clinical care. Hyperlactatemia was defined as lactate >2.2 mmol/L and lactic acidosis as lactate >5 mmol/L and pH <7.35. If lactate concentration was >5 mmol/L, consent was requested for measuring blood lactate and pyruvate using enzymatic laboratory methods. Lactate/pyruvate ratio >25:1 indicated type A lactic acidosis.
  
  
  RESULTS
  Eighty-seven (83%) children had lactate >2.2 mmol/L and 47 (45%) had lactate >5 mmol/L. Of those with lactate >5 mmol/L, 33 (70%) had corresponding blood pH <7.35. Lactate/pyruvate ratios were obtained for 16 patients. Of these, lactate/pyruvate ratio was <10 in three patients; 10-25 in 11; >25 in one; and indeterminate in one.
  
  
  CONCLUSIONS
  Lactic acidosis is common in children with acute severe asthma and is primarily type B occurring in the presence of normal oxygen delivery.
authors: Department of Pediatrics, Children's Hospital of Michigan, Wayne State University, Detroit, MI, USA. kmeert@med.wayne.edu
authors: Kathleen L
authors: KL
authors: Meert
authors: LaTasha
authors: L
authors: McCaulley
authors: Ashok P
authors: AP
authors: Sarnaik
mesh_terms: D000140:Acidosis, Lactic / Q000209:etiology* / Q000503:physiopathology; D000293:Adolescent; D001784:Blood Gas Analysis; D001993:Bronchodilator Agents / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006776:Hospitals, Pediatric; D006801:Humans; D015278:Intensive Care Units, Pediatric; D019344:Lactic Acid / Q000097:blood*; D008297:Male; D010102:Oxygen Inhalation Therapy / Q000379:methods; D011446:Prospective Studies; D011773:Pyruvates / Q000097:blood; D018570:Risk Assessment; D012720:Severity of Illness Index; D013224:Status Asthmaticus / Q000150:complications* / Q000503:physiopathology / Q000628:therapy; D016896:Treatment Outcome
chemical_list: D001993:Bronchodilator Agents; D011773:Pyruvates; D019344:Lactic Acid