The Effect of Regional Analgesia on Vascular Tone in Hip Arthroplasty Patients

BACKGROUND: While it is assumed that neuraxial analgesia and pain management may beneficially influence perioperative hemodynamics, few studies provided data quantifying such effects and none have assessed the potential contribution of the addition of a nerve block. QUESTIONS/PURPOSES: This clinical trial compared the visual analog scale (VAS) scores and measurement of arterial tone using augmentation index of patients who received combined spinal-epidural (CSE) only to patients who received both CSE and lumbar plexus block. METHODS: After obtaining written consent, 92 patients undergoing total hip arthroplasty were randomized to receive either CSE or CSE with lumbar plexus block (LPB). Perioperative pain and arterial tone were measured using VAS scores and augmentation index (AI) respectively, at baseline and at various times postoperatively. RESULTS: After the exclusion of 2 patients, 44 patients received CSE alone and 46 patients received CSE and LPB. Patient demographics and perioperative characteristics were similar in both groups. AI continuously decreased after placement of a CSE with or without LBP, beyond full resolution of neuraxial and peripheral blockade. Although the LPB group demonstrated a statistically significant reduction of VAS pain scores in the postanesthesia care unit (PACU; P < 0.05), overall, the addition of a LPB did not significantly reduce the AI when compared to the control group. CONCLUSION: The addition of a LPB provided better pain control in the PACU but did not reduce the AI, compared to the control group. We conclude that the addition of a LPB may have limited ability to affect arterial tone in the presence of a continuous infusion of epidural analgesics. In summary, the addition of a LPB in patients undergoing total hip arthroplasty is clinically effective and provided better pain control, especially in the immediate postoperative period. The continuous decrease on the AI in both groups beyond the full resolution of the neuroaxial and LPB will require further studies.