Clinical Trial: The Use of Constant-flow Technique for Determining the Lower Inflexion Point of Pressure-volume Curve and Intrinsic PEEP During One-lung Ventilation

Study Status: Active, not recruiting
Recruit Status: Active, not recruiting
Study Type: Interventional

Official Title:

Brief Summary:

One method for treating intraoperative hypoxia during one-lung ventilation (OLV) is application of PEEP to the dependent lung. However, only a minority of patients benefit from this maneuver. The effect of applied PEEP on oxygenation depends on the relation between the total end-expiratory pressure and the lower inflexion point (LIP) of pressure-volume curve (1). LIP during OLV can be determined with super-syringe technique, but is too complicated for routine operating room use. An alternative is the constant-flow method which is easy and widely used in intensive care settings (2). The investigators goal was to confirm that the constant-flow method as applied by an intensive care ventilator works during OLV.

Methods: After IRB approval and written, informed consent, data were obtained from 20 patients during OLV for thoracic surgery who were ventilated with an AVEA (VIASYS Healthcare) critical-care ventilator. During two-lung ventilation (TLV) and OLV 8 ml•kg-1 tidal volume was used. During OLV, ventilation periods of ten minutes, with and without 5 cmH2O PEEP were alternated. During each period, the investigators recorded arterial blood partial pressures, respiratory and hemodynamic values, intrinsic PEEP (PEEPi), and LIP. PEEPi and LIP were determined using the automatic mode of the ventilator; specifically, LIP was determined with a continuous flow of 3L/minute.

Detailed Summary:
Sponsor: The Cleveland Clinic

Current Primary Outcome:

• intrinsic positive end-expiratory pressure (PEEP) during ventillation [ Time Frame: 10 minutes ]
  constant-flow method useful for determination of intrinsic positive end-expiratory pressure (PEEPi) during OLV
• lower inflexion point (LIP) of P-V curve during one lung ventillation (OLV) [ Time Frame: 10 minutes ]
  constant-low method useful for determination of lower inflexion point (LIP) of P-V curve during one lung ventillation (OLV).
• net change of Lower Inflexion Point (LIP)- intrinsic positive end-expiratory pressure (PEEPi) ditstance with PEEP [ Time Frame: 10 minutes ]
  Relationship between the net change of lower inflexion point (LIP)- positive end-expiratory pressure (PEEPi) ditstance with and without positive end-expiratory pressure (PEEP) and change of PaO2 is useful during OLV for determination of patients reaction for application extternal positive end-expiratory pressure (PEEP)
• net change of lower inflexion point (LIP)-PEEPi ditstance without PEEP [ Time Frame: 10 minutes ]
  Relationship between the net change of lower inflexion point (LIP)-intrinsic positive end-expiratory pressure (PEEPi) ditstance with and without positive end-expiratory pressure (PEEP) and change of PaO2 is useful during one lung ventillation (OLV) for determination of patients reaction for application external positive end-expiratory pressure (PEEP).

Original Primary Outcome: Same as current

Current Secondary Outcome:

Original Secondary Outcome:

Information By: The Cleveland Clinic

Dates:
Date Received: February 2, 2012
Date Started: December 2011
Date Completion: March 2018
Last Updated: December 15, 2016
Last Verified: December 2016