Influence of Nociception Level Monitor (NOL) Guided Analgesic Delivery on Robot-assisted Colorectal Surgery

During anesthesia for surgical procedures, anesthetic and muscle relaxant drugs can bemeticulously administered using Bispectral Index (BIS) and neuromuscular monitors.However, analgesic drugs are still dispensed using poor surrogate parameters such asheart rate and blood pressure. This subjective dosing of analgesic drugs may invariablylead to inappropriate intra‐operative consumption. This may result in tachycardia,hypertension, and postoperative pain due to e.g. insufficient analgesia, or hypotension,bradycardia, respiratory depression and Post‐Operative Nausea and Vomiting (PONV)secondary to excessive analgesia. These effects may be detrimental to the patientsespecially those with multiple comorbidities with limited vital organ reserves such aspatients classified to III or IV by the American Society of Anaesthesia classification(ASA) Similarly, immediate postoperative recovery may also get delayed due to pain,unstable hemodynamics, nausea and vomiting. In that context, there has long been searchfor a monitor which can guide meticulous administration of analgesics. Recently, aNociception Level monitor (NOL) based on advanced software algorithms using multiplephysiological parameters has been developed. It offers an objective score (NOL Index)which relates to the level of intra‐operative pain. NOL technology has been validated andfound superior to existing pain indicators in peer‐reviewed publications. The NOL monitormay offer interesting observations in perioperative nociception levels and appropriateanalgesic consumption in diverse surgeries, including robot‐assisted surgery. Theseobservations may supplement the current efforts towards further advantages in rapidrestitution. Therefore, the investigators are planning a trial where intra‐operativeanalgesics are guided using an NOL monitor.