Evaluation of a preoperative pain score in response to pressure as a marker of postoperative pain and drugs consumption in surgical thyroidectomy
The Clinical Journal of Pain, 05/15/2012
Rago R et al. – The use of a preoperative test to assess individual pain threshold may be predictive for postoperative pain and analgesic request. The mathematical and statistical model used in this study confirms that a difference in the value of visual analog scale (VAS) of 3 shall be mathematically eligible for analgesia treatment.Methods
- Patients scheduled for total thyroidectomy underwent a preoperative pain test to assess the VAS value after a fixed stimulus (inflation of a sphygmomanometer with a pressure of 250 mm Hg).
- To estimate the power of the VAS in prediction of the postoperative analgesic requests, authors divided the patients into 3 groups according to the preoperative VAS values (A group, including all patients with preoperative VAS ≤3; B group including patients with preoperative VAS>3 ≤6; C group with preoperative VAS>6).
- Then authors correlated preoperative results with postoperative VAS values and postoperative analgesic drug consumption, analyzing the correlation between the sensitivity and the specificity of the VAS test for a range of different cutoff values.
- 32 patients were included.
- A group (10 patients) showed a medium postoperative VAS<4, and required less analgesics than other groups (ketorolac, 51 mg).
- B group (10 patients) and C group (12 patients) showed higher postoperative VAS value and required more analgesic drug (B, 80 mg; C, 90 mg+1 g acetaminophen).
- Using the receiver operating characteristic or relative operating characteristic examination and calculating the underlying area , authors could measure the discriminating ability of the test and found that the best VAS score cutoff was 3.