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The MicroRPM (Respiratory Pressure Meter) is our portable, non-invasive solution for the accurate assessment and management of the strength of the respiratory muscles. The handheld MicroRPM measures,

  • PImax/MIP (Maximal Inspiratory Pressure at the Mouth)
  • PEmax/MEP (Maximal Expiratory Pressure at the Mouth)
  • SNIP (Sniff Nasal Inspiratory Pressure)

In addition, with the optional PUMA PC software connected via Serial Port, live graphical displays, predicted values, incentive animations, measurements of fatigue (MRPD, MRR and Tau) and much, much more are available.

The MicroRPM is easy to use, operated by a simple three setting slide bar (Off, MIP/MEP, SNIP) and comes in a sturdy carry case. It is battery operated with a clear digital display of the results in CMH2O, using the latest piezo resistive pressure sensing technology for accurate and reliable measurement.

The respiratory muscles perform the vital function of sustaining ventilation, driving the inspiratory and expiratory breathing cycle, determining the ability to breathe.

The deterioration of the respiratory muscles, a result of pulmonary disease (COPD muscle atrophy, dystrophy and myopathy) or neuromuscular conditions (such as Motor Neurone Disease, Multiple Sclerosis, Surgical Trauma and Tetraplegia), leads to increasing levels of dyspnoea, disability and the eventual dependence upon mechanical ventilation. The above list is by no means exhaustive, but the early detection of respiratory muscle weakness, not always possible through the monitoring of lung volumes alone, enables early and effective treatment, with an improved quality of life as a result.

The lightweight MicroRPM is a simple, convenient device to quickly and efficiently monitor the strength of this important muscle group, to aid the early diagnosis of the respiratory muscle condition and monitor the subsequent effects of treatment (e.g. pharmacology, nutrition) and rehabilitation (e.g. exercise, inspiratory muscle training).

PImax/MIP

Maximal Inspiratory Pressure at the mouth is measured at RV (Residual Volume), lungs empty. A forceful inspiratory manoeuvre leading to a sustained maximal effort, during which time the best one second average is calculated, is followed by a natural release upon fatigue. The best result from 3 tests, with a suitable 1 or 2 minute recovery period between efforts, is used as the value of inspiratory muscle strength.

PEmax/MEP

Maximal Expiratory Pressure at the mouth is measured at TLC (Total Lung Capacity), lungs full. A forceful expiratory manoeuvre leading to a sustained maximal effort, during which time the best one second average is calculated, is followed by a natural release upon fatigue. The best result from 3 tests, with a suitable 1 or 2 minute recovery period between efforts, is used as the value of expiratory muscle strength.

Image Left: A typical graphical display, available on PUMA PC Software, for a PImax or PEmax manoeuvre. The shaded area represents the best one second from which an average pressure is calculated.

SNIP

Sniff Nasal Inspiratory Pressure is measured at FRC (Functional Residual Capacity), the bottom of the tidal breathing cycle, through one plugged nostril whilst the other remains open. A forceful, maximal inspiratory sniff is performed and a peak pressure value reported. The best result from between 5 and 10 tests is used as the value of sniff nasal inspiratory muscle strength.

Image Left: A typical graphical display, available on PUMA PC Software, for a SNIP manoeuvre.

PUMA PC Software

The PUMA (Pulmonary Management) PC software is a user-friendly, multi-window database management platform for the performance and analysis of respiratory muscle measurements. It provides a range of professional tools, such as:

  • Real time pressure graphs for mouth and nasal pressures
  • Pre and post medication/exercise tests
  • Report printouts
  • Trend graphs
  • Curve overlay facility
  • Predicted value sets
  • Incentive animation graphics
  • Search and sort functions

Additional measurements of fatigue are also included in the standard PUMA PC software:

  • MRPD (Maximum Rate of Pressure Development)
  • MRR (Maximum Rate of Relaxation)
  • Tau

Specifications


  • Measurements:

    PImax/MIP (Maximal Inspiratory Pressure at the Mouth)
    PEmax/MEP (Maximal Expiratory Pressure at the Mouth)
    SNIP (Sniff Nasal Inspiratory Pressure)





  • With Puma:

    MRPD (Maximum Rate of Pressure Development)
    MRR (Maximum Rate of Relaxation)
    Tau





  • Operating Pressure:

    ±300 cmH 2 O (±5PSID)



  • Burst Pressure:

    ±700 cmH 2 O (±20PSID)



  • Resolution:

    1 cmH 2 O



  • Accuracy:

    ±3%



  • Power Supply:

    Single 9V PP3



  • Dimensions:

    170x60x26mm



  • Weight:

    175g (unit); 750g (complete)



  • Operating Temperature

    0° C - 40° C



  • Operating Humidity:

    30% - 90% RH



  • Storage Temperature:

    -20° C - +70° C



  • Storage Humidity

    10% - 90% RH



Bibliography

  • 1 - ATS/ERS Statement on Rerspiratory Muscle Testing Am J Respir Crit Care Med Vol 166. pp 518-624, 2002

  • 2 - On the capacity of the lungs and on the respiratory functions. Hutchinson J. Med Chir Trans 1846; 29: 137-252

  • 3 - Maximal Respiratory Pressures: Normal Values and relationship to Age and Sex Leo F. Black and Robert E. Hyatt. American Review of Respiratory Disease, Volume 99, 1969

  • 4 - Predicted normal values for maximal respiratory pressures in Caucasian adults and children. S H Wilson, N T Cooke, R H T Edwards, S G Spiro. Thorax 1984: 39.535-538

  • 5 - Tests of Respiratory Muscle Function. Dudley F. Rochester, Clinics in Chest Medicine-Vol. 9. No.2. June 1988

  • 6 - Inspiratory Muscle training combined with general exercise reconditioning in patients with COPD. Paltiel Weiner, Yair Azgad, Rasem Ganam. Chest 1992;102:1351-1356

  • 7 - Resistive Inspiratory Muscle training in subjects with chronic cervical spinal cord injury. Alyssa Rutchik, Ann R. Weissman, Peter L. Almenoff, Ann M. Spungen,William A. Bauman, David R. Grimm Arch Phys Med Rehabil Vol 79, March 1998

  • 8 - Respiratory muscle disease: worth buying some equipment ? M.I. Polkey. Respiratory muscle laboratory, Royal Brompton Hospital. London

  • 9 - Dependence of maximal sniff generated mouth and transdiaphragmatic pressures on lung volume. Wanke, T., Schenz, G., Zwick, H., Popp, W., Ritschka, L., Flicker, M. (1990) Thorax. 45(5): pp 352-355.

  • 10 - Maximal Values of sniff nasal inspiratory pressure in healthy subjects.. Uldry, C., Fitting, J-W. (1995) Thorax. 50: pp. 371-375.

  • 11 - Sniff nasal inspiratory pressure. A non-invasive assessment of inspiratory muscle strength.Heritier, F., Rahm, F., Pasche, P., Fitting, J.W. (1994) American Journal of Respiratory Care Medicine. 150: pp. 1678- 1683.

  • 12 - Respiratory Muscle Testing. Moxham, J. (1996) Monaldi Arch Chest Dis. 51(6): pp 483-488. Review.

  • 13 - Sniff nasal inspiratory pressure: reference values in Caucasian children. Stefanutti, D., Fitting, J-W. (1999). American Journal Respiratory Care Medicine. 159: pp 107-111.