title: Incidence of hypo- and hypercarbia in severe traumatic brain injury before and after 2003 pediatric guidelines.
abstract: OBJECTIVE
  To examine the incidence of severe hypocarbia (PaCO2 <30 mm Hg) in patients with severe pediatric traumatic brain injury before and after publication of the 2003 pediatric guidelines (PG).
  
  
  METHODS
  Retrospective cohort analysis.
  
  
  METHODS
  Harborview Medical Center, Seattle, Washington (January 1, 1995, to December 31, 2005).
  
  
  METHODS
  Children <15 yrs of age with severe pediatric traumatic brain injury.
  
  
  METHODS
  None.
  
  
  RESULTS
  The pre-PG group (before August 1, 2003) included 375 patients and the post-PG group included 89 patients. Post PG guidelines, there was a trend toward earlier (45 vs. 32 mins; p = .05) and more frequent (7.1 vs. 8.4 samples; p = .06) PaCO2 sampling within 48 hrs of admission. Children 0-2 yrs had a longer time (75.0 mins) between admission and first PaCO2 sample than older children (44.3 mins; p < .01). The youngest children also had the highest incidence of severe hypocarbia on the first PaCO2 sample (31% vs. 19%; p = .02). Incidence of severe hypocarbia was high and did not decline (60% vs. 52%; p = .2) after the PG guidelines. However, over the 11 yrs, the odds of severe hypocarbia decreased (adjusted odds ratio 0.9; 95% confidence interval 0.84-0.96). During both periods, the incidence of severe hypocarbia was highest during the first 2 hrs after hospital admission. Intracranial pressure monitors were used more frequently post-PG. In 62 of 82 (77%) patients with severe hypocarbia in whom an intracranial pressure monitor was in place, the preceding intracranial pressure was <20 mm Hg. Severe hypocarbia independently predicted inpatient mortality (adjusted odds ratio 2.8; 95% confidence interval 1.3-5.9).
  
  
  CONCLUSIONS
  Although PaCO2 sampling was more frequent during the post-PG period and severe hypocarbia decreased during successive study years, the incidence of severe hypocarbia remained high during the first 48 hrs after hospital admission during the post-PG period. Time to PaCO2 sampling was longer in young children and associated with more severe hypocarbia. The presence of severe hypocarbia predicted mortality.
authors.affiliation: School of Medicine, University of Washington, Seattle, WA, USA.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Curry
authors.forename: Will
authors.initials: W
authors.lastname: Hollingworth
authors.forename: Richard G
authors.initials: RG
authors.lastname: Ellenbogen
authors.forename: Monica S
authors.initials: MS
authors.lastname: Vavilala
mesh_terms: D000293:Adolescent; D001930:Brain Injuries / Q000401:mortality / Q000503:physiopathology*; D002245:Carbon Dioxide / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D019983:Guideline Adherence; D017408:Guidelines as Topic; D006801:Humans; D006935:Hypercapnia / Q000453:epidemiology* / Q000209:etiology; D016857:Hypocapnia / Q000453:epidemiology* / Q000209:etiology; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D015278:Intensive Care Units, Pediatric; D008297:Male; D012121:Respiration, Artificial; D012189:Retrospective Studies; D012720:Severity of Illness Index; D014481:United States / Q000453:epidemiology
chemical_list: D002245:Carbon Dioxide