title: Variability in the establishment of an external reference point for central venous pressure measurement in children.
abstract: OBJECTIVE
  To investigate the variability in the establishment of the midaxillary line as external reference point (ERP), by different healthcare workers, for the measurement of central venous pressure in children.
  
  
  METHODS
  Descriptive and correlational study carried out in a pediatric intensive care unit of a teaching hospital. During the establishment of the midaxillary line as ERP for central venous pressure measurement, five assessments of the same patient made by healthcare workers and one assessment made by a trained evaluator were compared. A total of 120 assessments were made by 44 healthcare workers, 17 (38.6%) by nursing assistants and nursing technicians, 16 (36.3%) by nurses and 11 (25.1%) by physicians, in addition to 24 assessments made by the trained evaluator. The data were analyzed using the chi-square test, ANOVA, Kruskal-Wallis test and t test. Significance level was set at 5%.
  
  
  RESULTS
  There was statistically significant difference between the assessments made by healthcare workers and by the evaluator (p < 0.001). The comparison of the variability in the measurements made by healthcare workers revealed that 56 (46.7%) measurements were lower than those obtained by the evaluator (range from -0.5 to -9), 44 (36.7%) were higher (range from 0.5 to 4) and 20 (16.7%) were concordant (zero variability). Professional category did not influence the concordance between the ERPs (p = 0.899), or the variability observed (p = 0.778). However, the measurements made by professionals with greater experience in intensive care tended to differ more sharply from those made by the evaluators.
  
  
  CONCLUSIONS
  The indications of the midaxillary line as ERP presented variations when measured by the healthcare team and by the trained evaluator. Variability was not influenced by professional category, and the more experienced the healthcare worker, the greater the probability for underestimation of the ERP. According to the results of this study, such situations may compromise both the efficacy of this procedure and patient safety.
authors.affiliation: Cuidados Intensivos Pediátricos, Universidade Federal de São Paulo (UNIFESP), São Paulo, SP, Brasil.
authors.forename: Aline S C
authors.initials: AS
authors.lastname: Belela
authors.forename: Mavilde L G
authors.initials: ML
authors.lastname: Pedreira
authors.forename: Maria Angélica S
authors.initials: MA
authors.lastname: Peterlini
authors.forename: Denise M
authors.initials: DM
authors.lastname: Kusahara
authors.forename: Werther B
authors.initials: WB
authors.lastname: Carvalho
authors.forename: Gisele C
authors.initials: GC
authors.lastname: Gentil
mesh_terms: D000704:Analysis of Variance; D001367:Axillary Vein / Q000502:physiology*; D001795:Blood Pressure Determination / Q000592:standards*; D002496:Central Venous Pressure / Q000502:physiology*; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D006282:Health Personnel / Q000592:standards; D006801:Humans; D007223:Infant; D015278:Intensive Care Units, Pediatric; D012015:Reference Standards; D018709:Statistics, Nonparametric