Hamilton -Model P/V Tool Pro -Protective ventilation tool for diagnosis and recruitment
The Protective Ventilation Tool (P/V Tool Pro) performs a respiratory mechanics maneuver that records a quasi-static pressure/volume curve. This method can be used to assess lung recruitability and determine the recruitment strategy to apply. The P/V Tool Pro can also be used to perform a sustained inflation recruitment maneuver and measure the increase in lung volume. It is particularly helpful for ARDS patients, as selecting an appropriate lung recruitment strategy and the correct PEEP setting as an anti-derecruiting force are critical for this patient group. In combination with esophageal pressure measurement, the P/V Tool Pro can give you a clearer understanding of the lung and chest-wall mechanics. This enables you to apply a lung-protective ventilation strategy by titrating the PEEP level (Talmor 2008), and optimizing the parameters for the recruitment maneuver, driving pressure and tidal volume.
- Respiratory mechanics maneuver that records a quasi-static pressure/volume curve
- Easy to assess recruitability of ARDS patients
- Simple and safe way to perform lung recruitment maneuvers
- Can be combined with esophageal pressure measurement
Quasi-static P/V curve
- The P/V Tool is equivalent to the CPAP method for tracing static PV curves of the respiratory system (Piacentini 2009).
- Survival is higher in patients with protective ventilation, including PEEP set based on LIP, than conventional ventilation (Amato 1998).
- In ARDS patients, linear compliance of the respiratory system (Crs) is correlated with recruitability (Veillard-Baron 2003).
- Hysteresis of the P/V curve can be used to assess the recruitability of the lung at the bedside (Demory 2008).
Recruitment maneuver by sustained inflation
- In early ARDS it was possible to open the lung in the majority of patients (Borges 2006).
- During sustained inflation, most of the recruitment ocurred during the first 10 seconds (Arnal 2011).
P/V Tool Pro maneuvers can be performed without having to disconnect the breathing circuit or make changes to the mode or ventilator settings. Normal ventilation can be resumed at any time.
Quasi-static P/V curve
The P/V Tool Pro records the pressure volume relation of the lungs at low flow conditions (2 cmH2O/s). The breathing circuit is pressurized linearly to the operator-set pressure target. When the pressure reaches the target, pressure is reduced back to the starting pressure. The resulting curves can be used to analyze:
- The lower inflection point of the inflation pressure/volume curve
- The linear compliance of the inflation pressure/volume curve
- The hysteresis (the difference in volume between the two curves)
Sustained inflation recruitment maneuver
The breathing circuit is pressurized linearly to the operator-set target pressure at the operator-set ramp speed, and the resulting volume changes are recorded. When the pressure reaches the target, an operator-set pause is executed. After the pause, pressure is released linearly to the operator-set end-PEEP level. The integration of the flow during the pause is the recruited volume.