Hamilton G5 - Contraindications for Use; How the P;V Tool Works

9-4 624074/07
9 P/V tool maneuver option
9.1.4 Contraindications for use
• Patients who are breathing spontaneously
• Patients with unstable cardiovascular dynamics
• Patients with confirmed or suspected intracranial hyper-
tension
• Patients who cannot tolerate high intrapulmonary pressure
for other reasons
• Patients vulnerable to baro- or volutrauma
• Leaks in the system (patient and/or breathing circuit)
9.1.5 How the P/V Tool works
The P/V Tool records the pressure-volume relation of the lungs
at close to zero flow. Perform these tasks as presented:
1. Maneuver initiation. The operator initiates the maneuver
by pressing
Start/Stop .
2. Prolonged exhalation. The exhalation phase of the cur-
rent control breath is prolonged, and pressure is reduced
to the operator-set
Pstart level. The exhalation lasts
10 x RCexp, or a minimum of 6 s and a maximum of 15 s.
3. Linear pressure increase (inflation limb). The breathing
circuit is pressurized linearly to the operator-set
Ptop pres-
sure at the operator-set
Ramp speed . Resultant volume
changes are recorded.
4. Pause at
Ptop. When the pressure reaches Ptop , any
operator-set
Tpause is performed. The inspiratory and
expiratory valves are closed during the pause.
5. Linear pressure decrease (deflation limb). Pressure is
released linearly to the operator-set
End PEEP level. The
Ramp speed defines the rate of pressure decrease.
6. Ventilation resumes at new PEEP
(End PEEP). Ventila-
tion resumes when
End PEEP is reached. The P/V Tool win-
dow remains open with the curve frozen for analysis.