Newly Published
Perioperative Medicine  |   December 2017
Physiologic Evaluation of Ventilation Perfusion Mismatch and Respiratory Mechanics at Different Positive End-expiratory Pressure in Patients Undergoing Protective One-lung Ventilation
Author Notes
  • From the Department of Morphology, Surgery and Experimental Medicine, Intensive Care Unit, Sant’Anna Hospital, Ferrara, Italy (S.S., A.F., G.B., R.R., M.V., N.G.C., C.A.V.); Department of Emergency and Organ Transplant, Aldo Moro University of Bari, Bari, Italy (S.G.); Respiratory and Critical Care Group, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark (D.S.K., S.E.R.); Research Centre on Asthma and Chronic Obstructive Pulmonary Disease, Department of Medical Sciences, University of Ferrara, Ferrara, Italy (M.C.); and Department of Anesthesia and Intensive care, University of Foggia, Foggia, Italy (G.C.).
  • Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are available in both the HTML and PDF versions of this article. Links to the digital files are provided in the HTML text of this article on the Journal’s Web site (www.anesthesiology.org).
    Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are available in both the HTML and PDF versions of this article. Links to the digital files are provided in the HTML text of this article on the Journal’s Web site (www.anesthesiology.org).×
  • Submitted for publication June 17, 2017. Accepted for publication November 7, 2017.
    Submitted for publication June 17, 2017. Accepted for publication November 7, 2017.×
  • Research Support: Support was provided solely from institutional and/or departmental sources.
    Research Support: Support was provided solely from institutional and/or departmental sources.×
  • Competing Interests: None of the authors received compensation to perform this study. Dr. Rees is a board member and minor shareholder of Mermaid Care A/S (Nørresundby, Denmark), who commercially produces the ALPE system. Dr. Karbing has performed consultancy work for Mermaid Care A/S. The other authors declare no competing interests.
    Competing Interests: None of the authors received compensation to perform this study. Dr. Rees is a board member and minor shareholder of Mermaid Care A/S (Nørresundby, Denmark), who commercially produces the ALPE system. Dr. Karbing has performed consultancy work for Mermaid Care A/S. The other authors declare no competing interests.×
  • Correspondence: Address correspondence to Dr. Spadaro: Sant’Anna Hospital, University of Ferrara, 8, Aldo Moro, 44121 Ferrara, Italy. savinospadaro@gmail.com. Information on purchasing reprints may be found at www.anesthesiology.org or on the masthead page at the beginning of this issue. Anesthesiology’s articles are made freely accessible to all readers, for personal use only, 6 months from the cover date of the issue.
Article Information
Perioperative Medicine / Respiratory System / Thoracic Anesthesia
Perioperative Medicine   |   December 2017
Physiologic Evaluation of Ventilation Perfusion Mismatch and Respiratory Mechanics at Different Positive End-expiratory Pressure in Patients Undergoing Protective One-lung Ventilation
Anesthesiology Newly Published on December 7, 2017. doi:10.1097/ALN.0000000000002011
Anesthesiology Newly Published on December 7, 2017. doi:10.1097/ALN.0000000000002011
Abstract

Background: Arterial oxygenation is often impaired during one-lung ventilation, due to both pulmonary shunt and atelectasis. The use of low tidal volume (VT) (5 ml/kg predicted body weight) in the context of a lung-protective approach exacerbates atelectasis. This study sought to determine the combined physiologic effects of positive end-expiratory pressure and low VT during one-lung ventilation.

Methods: Data from 41 patients studied during general anesthesia for thoracic surgery were collected and analyzed. Shunt fraction, high V/Q and respiratory mechanics were measured at positive end-expiratory pressure 0 cm H2O during bilateral lung ventilation and one-lung ventilation and, subsequently, during one-lung ventilation at 5 or 10 cm H2O of positive end-expiratory pressure. Shunt fraction and high V/Q were measured using variation of inspired oxygen fraction and measurement of respiratory gas concentration and arterial blood gas. The level of positive end-expiratory pressure was applied in random order and maintained for 15 min before measurements.

Results: During one-lung ventilation, increasing positive end-expiratory pressure from 0 cm H2O to 5 cm H2O and 10 cm H2O resulted in a shunt fraction decrease of 5% (0 to 11) and 11% (5 to 16), respectively (P < 0.001). The Pao2/Fio2 ratio increased significantly only at a positive end-expiratory pressure of 10 cm H2O (P < 0.001). Driving pressure decreased from 16 ± 3 cm H2O at a positive end-expiratory pressure of 0 cm H2O to 12 ± 3 cm H2O at a positive end-expiratory pressure of 10 cm H2O (P < 0.001). The high V/Q ratio did not change.

Conclusions: During low VT one-lung ventilation, high positive end-expiratory pressure levels improve pulmonary function without increasing high V/Q and reduce driving pressure.