NCT01532245

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

• Status: Withdrawn
• Phase: N/A
• Study type: Interventional
• Enrollment: 0 (actual)
• Sponsor: The Cleveland Clinic · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

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.

Conditions

• One Lung Ventillation (OLV)
• Two Lung Ventillation (TLV)
• Positive End Expiratory Pressure (PEEP)
• Zero End-expiratory Pressure (ZEEP)

Interventions

Type	Name	Description
OTHER	two lung ventilation (TLV)	During two-lung ventilation (TLV) and OLV 8 ml•kg-1 tidal volume was used.
OTHER	one lung ventilation (OLV) without PEEP	During OLV, ventilation periods of ten minutes, with and without 5 cmH2O positive end-expiratory pressure (PEEP) were alternated.
OTHER	One lung ventilation (OLV) with positive end-expiratory pressure (PEEP)	During OLV, ventilation periods of ten minutes, with and without 5 cmH2O positive end-expiratory pressure (PEEP) were alternated

Timeline

• Start date: 2011-12-01
• Primary completion: 2018-10-23
• Completion: 2018-10-23
• First posted: 2012-02-14
• Last updated: 2018-10-25