title: The prehospital intravenous access assessment: a prospective study on intravenous access failure and access delay in prehospital emergency medicine.
abstract: OBJECTIVE
  Intravenous access in prehospital emergency care allows for early administration of medication and extended measures such as anaesthesia. Cannulation may, however, be difficult, and failure and resulting delay in treatment and transport may have negative effects on the patient. Therefore, our study aims to perform a concise assessment of the difficulties of prehospital venous cannulation.
  
  
  METHODS
  We analysed 23 candidate predictor variables on peripheral venous cannulations in terms of cannulation failure and exceedance of a 2 min time threshold. Multivariate logistic regression models were fitted for variables of predictive value (P<0.25) and evaluated by the area under the curve (AUC>0.6) of their respective receiver operating characteristic curve.
  
  
  RESULTS
  A total of 762 intravenous cannulations were enroled. In all, 22% of punctures failed on the first attempt and 13% of punctures exceeded 2 min. Model selection yielded a three-factor model (vein visibility without tourniquet, vein palpability with tourniquet and insufficient ambient lighting) of fair accuracy for the prediction of puncture failure (AUC=0.76) and a structurally congruent model of four factors (failure model factors plus vein visibility with tourniquet) for the exceedance of the 2 min threshold (AUC=0.80).
  
  
  CONCLUSIONS
  Our study offers a simple assessment to identify cases of difficult intravenous access in prehospital emergency care. Of the numerous factors subjectively perceived as possibly exerting influences on cannulation, only the universal - not exclusive to emergency care - factors of lighting, vein visibility and palpability proved to be valid predictors of cannulation failure and exceedance of a 2 min threshold.
authors.affiliation: aDepartment of Anaesthesiology, Erlangen University Hospital bDepartment of Medical Informatics, Biometry and Epidemiology, Friedrich-Alexander University Erlangen, Erlangen, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Prottengeier
authors.forename: Matthias
authors.initials: M
authors.lastname: Albermann
authors.forename: Sebastian
authors.initials: S
authors.lastname: Heinrich
authors.forename: Torsten
authors.initials: T
authors.lastname: Birkholz
authors.forename: Christine
authors.initials: C
authors.lastname: Gall
authors.forename: Joachim
authors.initials: J
authors.lastname: Schmidt
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002406:Catheterization, Peripheral / Q000592:standards / Q000706:statistics & numerical data*; D002983:Clinical Competence / Q000592:standards / Q000706:statistics & numerical data; D004632:Emergency Medical Services / Q000592:standards / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013997:Time Factors; D017211:Treatment Failure