title: Continuous glucose monitoring--a study of the Enlite sensor during hypo- and hyperbaric conditions.
abstract: BACKGROUND
  The performance and accuracy of the Enlite(™) (Medtronic, Inc., Northridge, CA) sensor may be affected by microbubble formation at the electrode surface during hypo- and hyperbaric conditions. The effects of acute pressure changes and of prewetting of sensors were investigated.
  
  
  METHODS
  On Day 1, 24 sensors were inserted on the right side of the abdomen and back in one healthy individual; 12 were prewetted with saline solution, and 12 were inserted dry. On Day 2, this procedure was repeated on the left side. All sensors were attached to an iPro continuous glucose monitoring (CGM) recorder. Hypobaric and hyperbaric tests were conducted in a pressure chamber, with each test lasting 105 min. Plasma glucose values were obtained at 5-min intervals with a HemoCue(®) (Ängelholm, Sweden) model 201 glucose analyzer for comparison with sensor glucose values.
  
  
  RESULTS
  Ninety percent of the CGM systems operated during the tests. The mean absolute relative difference was lower during hyperbaric than hypobaric conditions (6.7% vs. 14.9%, P<0.001). Sensor sensitivity was slightly decreased (P<0.05) during hypobaric but not during hyperbaric conditions. Clarke Error Grid Analysis showed that 100% of the values were found in the A+B region. No differences were found between prewetted and dry sensors.
  
  
  CONCLUSIONS
  The Enlite sensor performed adequately during acute pressure changes and was more accurate during hyperbaric than hypobaric conditions. Prewetting the sensors did not improve accuracy. Further studies on type 1 diabetes subjects are needed under various pressure conditions.
authors.affiliation: Göteborg Pediatric Growth Research Center, Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg, Göteborg, Sweden. peter.adolfsson@vgregion.se
authors.forename: Peter
authors.initials: P
authors.lastname: Adolfsson
authors.forename: Hans
authors.initials: H
authors.lastname: Örnhagen
authors.forename: Bengt M
authors.initials: BM
authors.lastname: Eriksson
authors.forename: Ken
authors.initials: K
authors.lastname: Cooper
authors.forename: Johan
authors.initials: J
authors.lastname: Jendle
mesh_terms: D000005:Abdomen; D000328:Adult; D000465:Algorithms; D001273:Atmosphere Exposure Chambers; D015374:Biosensing Techniques / Q000295:instrumentation*; D001786:Blood Glucose / Q000378:metabolism*; D015190:Blood Glucose Self-Monitoring; D006801:Humans; D008991:Monitoring, Physiologic / Q000379:methods*; D013548:Sweden
chemical_list: D001786:Blood Glucose