title: An in vitro and in vivo validation of a novel color-coded syringe device for measuring the intracuff pressure in cuffed endotracheal tubes.
abstract: BACKGROUND
  The clinical practice of pediatric anesthesiology has changed with a transition to the use of cuffed endotracheal tubes (ETTs) in infants and children. The monitoring of intracuff pressure has been suggested as one means to limit the potential for damage to the tracheal mucosa. The current study evaluates the accuracy of a novel, color-coded syringe device which provides three zones (green, clear, and red) to estimate the intracuff pressure.
  
  
  METHODS
  The study was conducted in two phases. Phase 1 was an in vitro study where cuffed ETTs of sizes 4.0 mm, 5.0 mm and 6.0 mm ID were placed into polyvinylchloride tubing of appropriate sizes. A manometer and the syringe device were simultaneously attached to measure the intracuff pressure at the middle of the 3 different zones on the device (red, clear, and green). Phase 2 was an in vivo study where the syringe device and the manometer were simultaneously attached to the pilot balloon to measure the intracuff pressure and the corresponding zone on the color-coded syringe following endotracheal intubation. Statistical analysis included a descriptive reporting of the mean ± SD, median, range, and 95% confidence intervals (CI) of the actual intracuff pressure readings at the three zones of the syringe device during both its in vitro and in vivo use.
  
  
  RESULTS
  For phase 1 of the study, the 95% CI for the green, clear, and red zones were 21.5-21.8, 29.2-29.5, and 46.5-47.4 cmH2O respectively. This correlated well with the manufacturer reported values of 20-30, 30-40, and 40-60 cmH2O for the 3 zones (green, clear, and red respectively). Phase 2 of the study included 200 patients ranging in age from 0.1 to 21.8 years (6.7 ± 5.1 years) and in weight from 4.0 to 129.1 kilograms (29.4 ± 23.3 kgs). The size of the ETTs ranged from 3.0 to 7.0 mm ID. The intracuff pressure measured by the manometer ranged from 4 to 65 cmH2O (27.6 ± 9.7 cmH2O). The 95% CI for the green, clear, and red zones were 20.5-21.7, 27.7-29.1, and 41.2-46.5 cmH2O respectively. There was no significant differences noted when comparing different patient ages or sizes of ETT.
  
  
  CONCLUSIONS
  The current study demonstrates a clinically acceptable correlation between the zones on this novel, color-coded syringe device and the actual measurement of the intracuff pressure obtained by a manometer for both in vitro and in vivo use. This device is a simple, reliable, portable and affordable method to monitor intracuff pressure.
authors.affiliation: Department of Anesthesiology & Pain Medicine, Nationwide Children's Hospital Columbus, Ohio.
authors.forename: Mineto
authors.initials: M
authors.lastname: Kamata
authors.affiliation: Department of Anesthesiology & Pain Medicine, Nationwide Children's Hospital Columbus, Ohio.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kako
authors.affiliation: Department of Anesthesiology & Pain Medicine, Nationwide Children's Hospital Columbus, Ohio.
authors.forename: Archana S
authors.initials: AS
authors.lastname: Ramesh
authors.affiliation: Department of Anesthesiology & Pain Medicine, Nationwide Children's Hospital Columbus, Ohio ; Department of Anesthesiology & Pain Medicine, The Ohio State University Columbus, Ohio.
authors.forename: Senthil G
authors.initials: SG
authors.lastname: Krishna
authors.affiliation: Department of Anesthesiology & Pain Medicine, Nationwide Children's Hospital Columbus, Ohio ; Department of Anesthesiology & Pain Medicine, The Ohio State University Columbus, Ohio ; Department of Pediatrics, Nationwide Children's Hospital and The Ohio State University Columbus, Ohio.
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Tobias
keywords: Intracuff pressure; cuffed endotracheal tube; pediatric anesthesia