Can the use of a non-invasive monitor (QNox) predict stronger pain after an operation?
The accuracy of the EEG-based qNox monitor to predict moderate-severe acute postoperative pain in peri-operative patients
Prof THomas Ledowski
150 participants
Oct 30, 2018
Observational
Conditions
Summary
The qNox monitoring System (Conox Monitor; Fresenius Kabi) is an electroencephalogram-based (sticky electrode on forehead) dimensionless score (0-100) which claims to reflect levels of analgesia in anaesthetized patients. Higher levels of the score may reflect higher levels of noxious stimulation, or a higher likelihood of a patient to respond to noxious stimuli. Aim of the current study is to investigate whether a higher qNox score during, and at the end of surgery may be associated with a higher likelihood of significant postoperative pain. 150 patients scheduled for non-emergency surgery under sevoflurane/opioid anaesthesia and state entropy depth of anaesthesia monitoring will be included. In addition to standard monitoring, a row of sticky electrodes (similar to the ones used for monitoring the long-established state entropy monitor) will be placed on the patients’ forehead. No other intervention is done for the trial. QNox will be monitored specifically at the end of surgery before patient arousal. Once awake in recovery, patients’ pain will be rated on a numeric rating scale (0-10) every 5 minutes (as per recovery room routine). The first 4 pain ratings will be used to analyse any relationship between qNox and postoperative pain. No other study-related intervention will take place. Participating patients will neither be inconvenienced nor harmed in any way by inclusion in this trial.
Eligibility
Inclusion Criteria1
- Patients at/over 18 years of age scheduled for non-emergency surgery and anaesthesia with sevoflurane/opioid
Exclusion Criteria1
- Patients will be excluded from further analysis if they lack sufficient English language skills to communicate pain on a self-rated pain scale, have a condition or medication known or suspected of interacting with the acquisition of the eeg data (i.e. know epilepsy, known severe mental disorder), chronic pain (with opioid medication at home), use of ketamine at home or perioperatively within 30 min prior to the commencement of QNOX measurements, abuse of amphetamines or opioids, allergy to sticky tape.
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Interventions
Monitoring of the electroencephalogram-based QNox score during anaesthesia and recording 4 pain scores (5 minutely for first 15 min) after admission of a patient to the recovery room after surgery, as well as the total consumption of opioid-analgesics during the entire stay of a patient in the recovery room. This involves placement of a sticky sensor (single use QNox sensor) on the patient's forehead, as well as the patients to rate their pain (0-10) three times on a numeric rating scale for 15 min after recovery room admision.
Locations(1)
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ACTRN12618001662257