The reliability of a linear analogue for evaluating pain

Area of Science:

• Pain Management
• Psychometrics
• Clinical Assessment

Background:

• Assessing subjective pain intensity is crucial in clinical settings.
• Shorter visual analogue scales (VAS) may introduce greater variability in pain reporting.
• The reliability and validity of different VAS lengths require investigation.

Purpose of the Study:

• To compare the variability and reproducibility of linear analogue scales (LAS) of different lengths (5, 10, 15, 20 cm) for pain rating.
• To evaluate the impact of a pharmacological agent (pethidine) on LAS performance.
• To determine the suitability of LAS for assessing severe pain, such as labor pain.

Main Methods:

• Patients rated pain using LAS of varying lengths (5, 10, 15, 20 cm).
• Reproducibility was assessed through repeated ratings of recalled pain and constant stimuli.
• The effect of intramuscular pethidine (150 mg) on LAS accuracy and reproducibility was examined.

Main Results:

• LAS of 10, 15, and 20 cm showed significantly less variability than a 5 cm scale.
• LAS demonstrated good correlation for repeated pain ratings over time.
• Pethidine administration did not significantly affect the accuracy or reproducibility of the LAS ratings.

Conclusions:

• Longer linear analogue scales (10-20 cm) are more reliable and less variable for pain assessment than shorter scales.
• The linear analogue rating method is reproducible and sensitive to genuine changes in pain perception.
• Linear analogue scales are a suitable tool for recording patient opinions of severe pain, including labor pain.