Journal of Critical Care
Volume 25, Issue 3 , Pages 483-488, September 2010

Impact of endotracheal tube size on preextubation respiratory variables☆☆☆

  • Sangeeta Mehta, MD, FRCPC

      Affiliations

    • Division of Respirology and Interdepartmental Division of Critical Care Medicine, Department of Internal Medicine, Mount Sinai Hospital and University of Toronto, Toronto, Ontario, Canada M5G 1X5
    • Corresponding Author InformationCorresponding author. Mount Sinai Hospital, Toronto ON, Canada M5G 1X5. Tel.: +1 416 586 4800x4604; fax: +1 416 586 8480.
    • ,
  • Matthew J. Heffer, MD

      Affiliations

    • Division of Respirology and Interdepartmental Division of Critical Care Medicine, Department of Internal Medicine, Mount Sinai Hospital and University of Toronto, Toronto, Ontario, Canada M5G 1X5
    • ,
  • Nava Maham, MD

      Affiliations

    • Division of Respirology and Interdepartmental Division of Critical Care Medicine, Department of Internal Medicine, Mount Sinai Hospital and University of Toronto, Toronto, Ontario, Canada M5G 1X5
    • ,
  • David L. Nelson, RRT

      Affiliations

    • Division of Pulmonary and Critical Care Medicine, Rhode Island Hospital and Brown University, Providence, RI 02906, USA
    • Division of Respiratory Care, Rhode Island Hospital and Brown University, Providence, RI 02906, USA
    • ,
  • James R. Klinger, MD, FCCP

      Affiliations

    • Division of Pulmonary and Critical Care Medicine, Rhode Island Hospital and Brown University, Providence, RI 02906, USA
    • ,
  • Mitchell M. Levy, MD, FCCM

      Affiliations

    • Division of Pulmonary and Critical Care Medicine, Rhode Island Hospital and Brown University, Providence, RI 02906, USA

published online 15 January 2010.

Abstract 

Purpose

Many parameters have been evaluated to predict successful extubation. These are all affected by extrapulmonary variables. The purpose of this study was to evaluate the effect of endotracheal tube (ETT) size on preextubation predictors of successful extubation.

Materials and Methods

Twenty-two intubated and mechanically ventilated subjects were recruited when ready for extubation. Subjects were ventilated with T-piece, continuous positive airway pressure (CPAP) of 5 cm H2O, and pressure support ventilation (PSV) of 5 cm H2O in randomized order for 15 minutes each. Pulmonary mechanics—including respiratory frequency (f), tidal volume (VT), f/VT ratio, negative change in esophageal pressure, pressure time product (PTP), work of breathing, and the airway occlusion pressure 100 milliseconds after the onset of inspiratory flow—were measured using a microprocessor-based monitor at the end of each interval. After extubation, measurement of pulmonary mechanics was repeated at 15 and 60 minutes.

Results

In patients with 7.0- or 7.5-mm ETT compared with patients with 8.0-mm ETT, (1) f was significantly higher during all ventilatory modes and 15 minutes after extubation; (2) VT during PSV and CPAP was significantly lower; (3) mean f/VT was significantly higher (122 ± 57 vs 69 ± 35, P = .026); and (4) PTP was significantly higher during CPAP, PSV, and 15 minutes after extubation. There was a nonsignificant trend toward increased negative change in esophageal pressure, work of breathing, and airway occlusion pressure 100 milliseconds after the onset of inspiratory flow in the smaller-ETT group.

Conclusions

The ETT size has a significant impact on f, VT, f/VT ratio, and PTP.

Abbreviations: CPAP, continuous positive airway pressure, ETT, endotracheal tube, f, respiratory frequency, P0.1, airway occlusion pressure 100 milliseconds after the onset of inspiratory flow, ΔPes, negative change in esophageal pressure, PSV, pressure support ventilation, PTP, pressure time product, RSBI, rapid shallow breathing index, VT, tidal volume, WOB, work of breathing

Keywords: Respiratory mechanics, Work of breathing, Ventilator weaning, Mechanical ventilation

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☆ Study institution: Rhode Island Hospital, Providence, RI.

☆☆ Support/Conflicts: Allied Health Care Products, Riverside, CA, provided the CP-100 and esophageal catheters. None of the authors has any financial or nonfinancial competing interests.

PII: S0883-9441(09)00282-2

doi:10.1016/j.jcrc.2009.11.005

Journal of Critical Care
Volume 25, Issue 3 , Pages 483-488, September 2010

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