Background and objective: The number of fluctuations in skin conductance per second has been shown to correlate with postoperative pain. In this context, the effects of cholinesterase inhibitors and anticholinergic drugs used for the reversal of muscle relaxants were investigated.
Methods: Muscle relaxant effects were reversed in 30 patients with neostigmine and glycopyrrolate. No reversal agents were given to 30 controls. Patients' level of pain was quantified using a numeric rating scale (0-10) at several time points in the recovery room. The number of fluctuations in skin conductance per second was measured simultaneously.
Results: The number of fluctuations in skin conductance per second was significantly higher in patients with no and severe pain in the control compared with the reversal group (no pain 0.19 vs. 0.12; severe pain 0.40 vs. 0.19). The number of fluctuations in skin conductance per second was less sensitive to identify time points with moderate/severe pain in the reversal group.
Conclusion: Skin conductance-based assessment of pain is affected by reversal agents.