Non-dependent Lung High Frequency Positive Pressure Ventilation (HFPPV) and Right Ventricular Function
Condition: Lung Diseases; Esophageal Diseases
MeSH terms: Esophageal Diseases; Lung Diseases
Study type: Interventional
Phase: Phase 1

Summary: 
      The investigators hypothesized that the application of volume-controlled HFPPV to the
      non-dependent lung during one-lung ventilation (OLV) for thoracotomy in patients with good
      pulmonary functions and mild-to-moderate pulmonary dysfunction may provide preservation of
      the right ventricular (RV) function, adequate oxygenation and optimum surgical conditions.

      The investigators evaluated the effects of IL-HFPPV on RV ejection fraction (REF), RV
      end-diastolic volume (RVEDVI), RV stroke work (RVSWI), pulmonary vascular resistance (PVRI),
      and stroke volume (SVI) indices, oxygen delivery (DO2) and uptake (VO2), shunt fraction (Qs:
      Qt), and surgical field conditions during OLV for thoracotomy in patients with good and
      mild-to-moderate impaired pulmonary functions.
    

Detailed description: 
      One-lung ventilation (OLV) provides an adequate operative field, but is opposed by the
      induced hypoxic pulmonary vasoconstriction (HPV) in the non-ventilated lung. It may preserve
      overall oxygen delivery, however with deleterious increase in shunt fraction and pulmonary
      vascular resistance.1-2Right ventricular (RV) overload resulting from these increases in its
      afterload influences postoperative morbidity and mortality. Intrinsic positive end-expiratory
      pressure (PEEPi) occurs frequently during OLV for thoracic surgery in the dependent lung of
      patients with pulmonary hyperinflation as opposed to patients with normal pulmonary
      function.3 The different approaches for the correction of hypoxemia during OLV may require
      some degree of recruitment of the non-dependent lung (IL), with different maneuvers such as
      the application of continuous positive pressure ventilation (CPAP) or high frequency jet
      ventilation (HFJV) to the non-dependent lung. These recruitment strategies, although they may
      improve arterial saturation, may concurrently decrease cardiac output, therefore having
      contradictory effects on overall oxygen delivery.4-6 Gas trapping may occur with increased
      ventilatory frequency during HFJV. This may impair RVEF through the increases in RV
      afterload.7 Therefore, the use of high frequency positive pressure ventilation (HFPPV) using
      tidal volumes just greater than the dead space increases arterial oxygen tension (PaO2) and
      the carbon dioxide excretion (VCO2) linearly with increasing peak airway pressure.8 We
      hypothesized that the application of volume-controlled HFPPV to the non-dependent lung during
      OLV for thoracotomy in patients with good pulmonary functions and mild-to-moderate pulmonary
      dysfunction may provide preservation of the RV function, adequate oxygenation and optimum
      surgical conditions.

      We evaluated the effects of IL-HFPPV on RV ejection fraction (REF), RV end-diastolic volume
      (RVEDVI), RV stroke work (RVSWI), pulmonary vascular resistance (PVRI), and stroke volume
      (SVI) indices, oxygen delivery (DO2) and uptake (VO2), shunt fraction (Qs: Qt), and surgical
      field conditions during OLV for thoracotomy in patients with good and mild-to-moderate
      impaired pulmonary functions.
    

Intervention name(s): conventional OLV followed with IL-HFPPV
Intervention type(s): Procedure
Intervention description(s): The patients' lungs were mechanically ventilated with intermittent positive pressure ventilation using fraction of inspired oxygen (FiO2) of 0.5 in air, tidal volume (VT) of 8 mL/kg, inspiratory to expiratory [I: E] ratio of 1:2.5, zero positive end-expiratory pressure (PEEP), respiratory rate (R.R) was adjusted to achieve an arterial carbon dioxide tension (PaCO2) 35-45 mm Hg and peak inspiratory pressures were limited to 35 cm H2O. After pleurotomy, OLV was initiated with the same ventilatory settings for the dependent lung. After 30 min, the non-dependent collapsed lung was ventilated using HFPPV mode (IL-HFPPV) with another identical ventilator, with an internal circuit of low compliance, using FiO2 of 0.5 in air, VT 3 mL/kg, I: E ratio <0.3 and R.R 60 breaths/min.
Other intervention name(s): KONTRON ABT 5300 ventilator, UK
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Thoracotomy; one lung ventilation; HFPPV; right ventricular function.