No clinical evidence of acute opioid tolerance after remifentanil-based anaesthesia
ABSTRACT We have prospectively assessed whether remifentanil-based anaesthesia is associated with clinically relevant acute opioid tolerance, expressed as greater postoperative pain scores or morphine consumption. Sixty patients undergoing elective gynaecological, non-laparoscopic, surgery were randomly assigned to receive remifentanil (group R, n=30) or sevoflurane (group S, n=30) based anaesthesia. Postoperative analgesia was provided with morphine through a patient-controlled infusion device. Mean (SD) remifentanil infusion rate in group R was 0.23 (0.10) microg kg(-1) min(-1) and mean inspired fraction of sevoflurane in group S was 1.75 (0.70)%. Mean (SD) cumulative morphine consumption during the first 24 postoperative hours was similar between groups: 28.0 (14.2) mg (group R) vs 28.6 (12.4) mg (group S). Pain scores, were also similar between groups during this period. These data do not support the development of acute opioid tolerance after remifentanil-based anaesthesia in this type of surgery.
SourceAvailable from: Javier Benito de la Víbora[Show abstract] [Hide abstract]
ABSTRACT: Perioperative opioids reduce inhalational anaesthetic requirements. The initial hypoalgesia may, however, be followed by a rebound hyperalgesia. To determine whether prior opioid administration influences inhalational anaesthetic requirements, which might be associated with opioid-induced hyperalgesia. A prospective, randomised, experimental study. Experimental Surgery, La Paz University Hospital, Madrid, Spain. Seventy-nine adult male Wistar rats. Sevoflurane minimum alveolar concentration (MAC) and mechanical nociceptive thresholds (MNTs) were assessed at baseline and 7 days later following opioid treatment with remifentanil 120 μg kg h, buprenorphine 150 μg kg, methadone 8 mg kg or morphine 10 mg kg. The duration of the effect of remifentanil on MAC and MNT was evaluated in addition to the preventive effect of ketamine 10 mg kg on remifentanil-induced hyperalgesia. The effect of different opioid treatments on MAC and MNT was evaluated using analysis of variance (ANOVA). All studied opioids produced an immediate reduction in sevoflurane MAC, followed by an increase (16%) in baseline MAC 7 days later (P < 0.05), although the immediate MAC reduction produced by these opioids at that time was not different. Remifentanil produced a decrease in MNT (P < 0.05), which was associated with an increase in the MAC (P < 0.05) that persisted at 21 days. The effect of remifentanil on MNT and MAC was blocked by ketamine. Opioid-induced hyperalgesia was associated with an increase in the MAC in normal rats who had not undergone surgery. Both effects lasted 21 days and were prevented by ketamine.European Journal of Anaesthesiology 04/2015; 32(4):232-41. DOI:10.1097/EJA.0000000000000188 · 3.01 Impact Factor
Article: Opioid-induced hyperalgesia[Show abstract] [Hide abstract]
ABSTRACT: Perioperative opioid-induced hyperalgesia (OIH) can be defined as the "increased perception of pain after opioid-based anesthesia and surgery" since hyperalgesia is defined as "increased pain from a stimulus that normally provokes pain." OIH has been identified mainly after remifentanil-based anesthesia in surgical patients given the high dose and rapid withdrawal used. The mechanisms of OIH have been postulated mainly by the cellular-level adaptation in internalization of the receptors and downregulation of intracellular coupling, upregulation of spinal dynorphins, and activation of N-methyl-D-aspartate receptors have been postulated as well. The clinical aspects of OIH with various causes, especially remifentanil, have been investigated. Pros and cons related to remifentanil-induced hyperalgesia have been suggested. The dose and duration of remifentanil used in surgery and anesthesia can be the appropriate factors for OIH, including the way of setting for the control groups of those studies, and the methods for evaluating the pain. Opioids remain one of the most powerful pain killers for acute pain management. Opioids are sometimes necessary for perioperative analgesia, but OIH can be an unavoidable risk. Ongoing interest in OIH and the development of anesthesia optimized for its prevention will increase the quality of perioperative life.Journal of the Korean Medical Association 01/2014; 57(1):41. DOI:10.5124/jkma.2014.57.1.41 · 0.18 Impact Factor