[Effect of ischemic tourniquet pressure on the intensity of postoperative pain]].

OBJECTIVE

To evaluate the influence of tourniquet pressure (TP) on the postoperative pain of patients undergoing total knee arthroplasty (TKA).

MATERIAL AND METHODS

This prospective double-blind study enrolled 86 patients scheduled for TKA. The patients were randomized to groups to receive either a high TP (400 mgHg) or a low TP (100 mgHg above systolic pressure). A spinal block was performed in each patient. Intravenous morphine and metamizol were infused through a patient-controlled analgesia device. Postoperative pain was estimated on a visual analog scale (VAS). We also recorded the amount of morphine infused, functional recovery of the limb and the presence of complications.

RESULTS

Surgical field conditions were considered good in all but two low PT cases. Postoperative pain was less intense in the low TP group at 6, 12, 24 and 36 hours, and that group required less morphine (11.38 +/- 4.9 mg vs. 15.13 +/- 4.9 mg, p < 0.05). More patients achieved 90 degrees flexion four days after surgery in the low TP group (65%) than in the high TP group (41%) (p < 0.05).

CONCLUSIONS

Applying a lower-than-usual TP in orthopedic surgery could be sufficient for reducing postoperative pain while still providing a bloodless surgical field.