Introduction:

Pressure algometry is a valid method to evaluate the sensory system of pain transmission in humans, using tests such as temporal summation and conditioned modulation of pain. The objective of this work was to carry out a preliminary experience in the Anesthesiology Service of our University Hospital, using pressure algometry as a quantitative sensory test.

Methodology:

In a first stage, a cross-sectional case-control study was carried out, without randomization, where the pressure pain threshold was measured by pressure algometry in 58 patients who consulted in the preoperative evaluation visit. Eighteen had some type of chronic pain (pain group) and 40 had no pain (pain-free group). In a second stage, an observational study was carried out on 36 healthy volunteers, anesthesiology residents. Temporal summation was studied in 16 and conditioned modulation of pain in 20, in both cases using pressure algometry. The application of cuff pressure to the arm was used as a heterotopic stimulus. Both tests were measured at the level of the right trapezius muscle.

Results:

In the group with pain, the pressure pain threshold value was lower than in the group without pain in all the points evaluated. The pain threshold va­lue at the mean pressure of the four regions analyzed in the group with pain, turned out to be lower than in the group without pain, 32.7 ± 10 Newtons versus 42 ± 11.7 Newtons (p = 0.004). The mean pressu­re pain threshold was lower in female patients than in male patients, 36.6 ± 9 Newtons versus 48 ± 11 Newtons (p = 0.001). In the 20 healthy volunteers who underwent the conditioned modulation of pain test at the trapezius level, the pain threshold at the initial pressu­re was 63 ± 27 Newtons and the final pressure was 72 ± 28 Newtons, with an average increase of 9 Newtons (14.2 %). In the 16 in which the temporal summa­tion test was carried out, it was found that the pain level of the numerical visual scale went from 4.1 ± 1.0 to 6.5 ± 1.5 between the first and tenth stimulus.

Conclusions:

The application of pressure algometry in patients who consulted in the preoperative polyclinic, showed that pain thresholds at mean pressure were lower in female patients with chronic pain. In healthy volunteers, temporal summation showed an increase in pain intensity as a normal expression of the "wind-up" phenomenon. In 80 % of healthy volunteers, conditioned pain modulation resulted in an increase in pressure pain threshold with the application of a heterotopic pain stimulus. Pressure algometry is a useful and practical instrument. The information obtained with the quantitative sensory tests can be very useful in the Acute and Chronic Pain Units.

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