title: Double lumen endotracheal tube for percutaneous tracheostomy.
abstract: BACKGROUND
  Percutaneous dilational tracheostomy is normally a bronchoscope-guided procedure. The insertion of a bronchoscope into an endotracheal tube (ETT) affects resistance, flow, and alveolar pressure. To improve airway management and ventilation during percutaneous tracheostomy, we developed a double lumen endotracheal tube (DLET). The aim of this in vitro study was to compare the linear constant of the Rohrer equation (K1), the nonlinear constant of the Rohrer equation (K2), the inspiratory and expiratory airway resistance, and ventilatory and airway pressures using the DLET with different standard sized ETTs.
  
  
  METHODS
  A trachea and lung model was used to compare the DLET to ETTs with 7, 7.5, and 8 mm inner diameters with and without a bronchoscope (4.5 mm external diameter), and 4 and 5 mm inner diameter ventilation tubes (F4, F5) of a translaryngeal tracheostomy. For each device, the pressure drop across the device and the Rohrer equation linear constant (K1) and nonlinear constant (K2) were calculated during a continuous flow of 10-90 L/min, the inspiratory and expiratory airway resistance values were calculated during volume controlled mechanical ventilation, and respiratory airway pressure values were calculated during volume and pressure controlled mechanical ventilation.
  
  
  RESULTS
  DLET had lower K2, pressure drop, and inspiratory and expiratory airway resistance compared with conventional ETTs plus fiberoptic bronchoscope. Furthermore, during mechanical ventilation, DLET had a lower value of peak pressure, mean pressure, and intrinsic PEEP than the other ETTs plus fiberoptic bronchoscope.
  
  
  CONCLUSIONS
  Use of the DLET during percutaneous dilational tracheostomy allows fiberoptic bronchoscopy without imposing excessive airway resistance. Reduced tube resistance during this procedure may confer additional safety in what is well known to be a hazardous procedure.
authors.affiliation: Department of Neuroscience and Reproductive and Odontostomatological Sciences, University of Naples "Federico II," Naples, Italy vargas.maria82@gmail.com.
authors.forename: Maria
authors.initials: M
authors.lastname: Vargas
authors.affiliation: Department of Neuroscience and Reproductive and Odontostomatological Sciences, University of Naples "Federico II," Naples, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Servillo
authors.affiliation: Department of Neuroscience and Reproductive and Odontostomatological Sciences, University of Naples "Federico II," Naples, Italy.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Tessitore
authors.affiliation: Anaesthesia and Intensive Care Unit, Istituto di Ricovero e Cura a Carattere Scientifico Neuromed, Pozzilli, Italy.
authors.forename: Fulvio
authors.initials: F
authors.lastname: Aloj
authors.affiliation: Department of Anesthesia and Intensive Care, Istituto di Ricovero e Cura a Carattere Scientifico, Azienda Ospedaliera Universitaria San Martino IST, University of Genoa, Genoa, Italy.
authors.forename: Iole
authors.initials: I
authors.lastname: Brunetti
authors.affiliation: Department of Anesthesia and Intensive Care, Istituto di Ricovero e Cura a Carattere Scientifico, Azienda Ospedaliera Universitaria San Martino IST, University of Genoa, Genoa, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Arditi
authors.affiliation: Department of Anesthesia and Intensive Care, Istituto di Ricovero e Cura a Carattere Scientifico, Azienda Ospedaliera Universitaria San Martino IST, University of Genoa, Genoa, Italy.
authors.forename: Dorino
authors.initials: D
authors.lastname: Salami
authors.affiliation: Department of Anesthesiology and Critical Care and the Department of Respiratory Care, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Kacmarek
authors.affiliation: Department of Surgical and Integrated Sciences and the Department Anesthesia and Intensive Care, Istituto di Ricovero e Cura a Carattere Scientifico, Azienda Ospedaliera Universitaria San Martino IST, University of Genoa, Genoa, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Pelosi
mesh_terms: D000403:Airway Resistance; D004867:Equipment Design; D006801:Humans; D007442:Intubation, Intratracheal / Q000295:instrumentation*; D008954:Models, Biological; D011175:Positive-Pressure Respiration / Q000379:methods*; D014139:Tracheostomy / Q000379:methods*
keywords: airway management; double lumen endotracheal tube; intensive care; tracheostomy