Impact of NOL Index Intraoperative Guided Remifentanil Analgesia

Overview

The Physiological Monitoring Device (PMD-200™) system is comprised of a monitor and a designated finger probe containing 4 sensors. The sensors included are Photoplethysmography (PPG), Galvanic Skin Response (GSR), Accelerometer for movement (ACC) and Thermistor for peripheral temperature (TMP). The PMD-200 is intended to be used for assessing the nociception level in anesthetized patients. The purpose of the study is confirmation of a reduction in the dosage of remifentanil allowed by the monitoring of nociception by the NOL which could open the way to a double control of the administration of anesthetic agents: control of the administration of hypnotics by the bispectral index (BIS) and control of the administration of opiate by the NOL.

The PMD-200 continuous pain monitor is intended to be used for assessing changes in pain levels. The system monitors the physiological responses to pain using a relative pain index from 0-100, called the Nociception Level (NOL®) index. In the NOL index, 0 represents no nociception or pain and 100 represents high nociception or pain level. The PMD-200 system consists of a monitor and a specific finger probe containing 4 sensors. The sensors included are Photoplethysmography (PPG), Galvanic Skin Response (GSR), Accelerometer for movement (ACC) and Thermistor for peripheral temperature (TMP). The PMD-200™ is intended to be used for assessing the nociception level in anesthetized patients. The device is European Conformity (CE) marked and commercially available. Meier et al. recently published a randomized trial involving 80 patients for major abdominal surgery, one group receiving routine care and the other NOL-guided analgesia. In the latter group, the remifentanil concentration was reduced when NOL values were below 10 or increased when NOL values were above 25 for at least 1 minute. In both groups, propofol was titrated to have bispectral index values between 45 and 55. Remifentanil administration was reduced in the NOL-guided group: 0.119 ± 0.033 vs 0.086 ± 0.032 μg.kg.min (p \< 0.001). In the NOL- guided group, 2 out of 40 (5%) patients had hypotension (mean blood pressure less than 55 mm Hg) compared to 11 out of 40 (28%) in the control group (p = 0.006) and 16 out of 40 (40%) patients received vasoactive drugs vs 25 out of 40 (63%) (p = 0.044). Previous results cover a small number of patients treated in a single center. The purpose of this study is to confirm this result within a multicenter study involving a larger group of patients. Confirmation of a reduction in the dosage of remifentanil allowed by the monitoring of nociception by the NOL will open the way to a double control of the administration of anesthetic agents: control of the administration of hypnotics by the bispectral index (BIS) and control of the administration of opiate by the NOL.