Pressure target increase in P/V Tool vs. continuous low flow

Author: Simon Franz, Reviewer: Matthias Himmelstoss, Thomas Reimer, Elmar Pätzold, Bernhard Schmitt

Does the Hamilton Medical P/V Tool® provide a real low flow pressure/volume (P/V) loop?

The Hamilton Medical P/V Tool is a pressure-targeted method for producing a quasi-static P/V loop.


Static compliance/flow relationship at a ramp speed of 2 cmH2O/s

Flows of less than or equal to 10 l/min seem to be quick, safe, and reliable for determining the lung mechanics by means of a P/V loop at the bedside.

We suggest using the minimum ramp speed of 2 cmH2O/s to eliminate the pressure change from resistive elements of the respiratory system (1).

When following these recommendations, the flow should be below 10 l/min up to a compliance of 75 ml/cm H2O as shown in the figure left. Most patients assessed for lung recruitability have a respiratory system compliance of less than 75 ml/cmH2O.



Paw/Flow plot

The flow can also be visualized by adding a Paw/Flow plot to the screen.









It is not possible to have control of the expiratory flow, because it is driven by the elastic recoil of the respiratory system. Deriving the deflation limb by means of a pressure-control approach is a reliable method that shows a good correlation with the radiological findings of a CT-scan (2).

With the P/V Tool, Hamilton Medical provides a real low flow pressure/volume loop for assessing lung recruitability. In addition, the P/V Tool can be used for reproducible, standardized and documentable lung recruitment maneuvers. Please refer to the documents available for download below for more information on using the P/V Tool.

Relevant devices: HAMILTON-G5/S1 (sw v2.8x), HAMILTON-C3 (sw v2.0.x), HAMILTON-C6 (sw v1.1.x)

See the documentation available for download below. For documentation in languages other than English, visit our Download area.


  1. Albaiceta, G. M., Taboada, F., Parra, D., Luyando, L. H., Calvo, J., Menendez, R., & Otero, J. (2004).Tomographic Study of the Inflection Points of the Pressure–Volume Curve in Acute Lung Injury. American Journal of Respiratory and Critical Care Medicine, 170(10), 1066-1072. doi:10.1164/rccm.200312-1644OC
  2. Blanc, Q., Sab, J.-M., Philit, F., Langevin, B., Thouret, J.-M., Noel, P., . . . Guérin, C. (2002). Inspiratory pressure-volume curves obtained using automated low constant flow inflation and automated occlusion methods in ARDS patients with a new device. Intensive Care Medicine, 28(7), 990-994. doi:10.1007/s00134-002-1316-4


Product Category Type/Size Date / PN Language
P/V Tool Pro quick reference card
63.3 KB



P/V Tool Pro user guide
1.2 MB



Validation of a new, automatic, pressure ramp method of acquirement<br/><br/>By: Daniela Pasero M.D., Giorgio A. Iotti M.D., and Mirko Belliato M.D.<br/><br/>PN 689213.00
Respiratory system pressure-volume curve
174.1 KB

PN 689213


Related Articles

Low flow, P/V Tool, lung recruitment, pressure volume, curve, recruitment maneuver

Date of Printing: 15.04.2021
The content of this Knowledge Base is intended for informational purposes only. Hamilton Medical AG provides no warranty with respect to the information contained in this Knowledge Base and reliance on any part of this information is solely at your own risk. For detailed instructions on operating your Hamilton Medical device, please refer to the official Hamilton Medical Operator’s Manual for the respective device.