Letters to the Editor: Letters & Announcements
To the Editor:
Collard et al.1 demonstrated that substituting an esmolol infusion for intraoperative fentanyl or remifentanil reduced postoperative fentanyl demand, diminished nausea, and accelerated discharge after laparoscopic cholecystectomy. The study design with two interventions in the same group (eliminating opioids and adding esmolol infusion) does not establish the definite cause-effect relationship.
Opioids provide an initial analgesic effect, but then reduce the pain threshold to less than baseline (opioid-induced hyperalgesia [OIH]) and increase the amount of drug required to achieve the same analgesia (tolerance).2,3 Remifentanil has been shown to increase pain and induce mechanical hyperalgesia after 30 min infusion at the dose 0.05–0.1 μg · kg−1· min−1 in volunteers.4–6 An alternative explanation for the decreased postoperative fentanyl requirement originally attributed to esmolol infusion1 is that non-opioid anesthetic technique does not cause OIH and tolerance.
Both β-blockers and opioids blunt the sympathetic response to nociception during the surgery, whereas a subanesthetic dose of inhalational anesthetics exacerbates this response.7 However, deepening inhaled anesthesia can achieve similar hemodynamic stability in most patients with additional benefit of anesthetic-induced preconditioning.8
OIH is modulated by anesthesia technique (e.g., use of N-methyl- d-aspartate antagonists), and some clinical studies have failed to demonstrate increased pain scores after remifentanil infusion.9 Whether postoperative opioid sparing is caused by the intraoperative opioid avoidance or an intrinsic β-blocker opioid sparing effect remains to be answered in additional studies. Study groups should be matched for intraoperative opioid usage (receive either none or the same dose).
Collard’s group finding that esmolol in the absence of opioids decreases the postoperative fentanyl requirement is clinically significant and relevant for ambulatory surgery. The question as to whether the diminished postoperative analgesic requirement after minimally invasive surgery is a result of presence of esmolol, absence of opioids or combination of these interventions remains to be answered.
Mindaugas Pranevicius, MD
Department of Anesthesiology
Albert Einstein College of Medicine
Jacobi Medical Center
Bronx, New York
Osvaldas Pranevicius, MD, PhD
Department of Anesthesiology
New York Hospital Queens
Flushing, New York
Dr. Carli does not wish to respond.
1.Collard V, Mistraletti G, Taqi A, Asenjo JF, Feldman LS, Fried GM, Carli F. Intraoperative esmolol infusion in the absence of opioids spares postoperative fentanyl in patients undergoing ambulatory laparoscopic cholecystectomy. Anesth Analg 2007;105:1255–62
2.Angst MS, Clark JD. Opioid-induced hyperalgesia: A qualitative systematic review. Anesthesiology 2006;104:570–87
3.Koppert W, Schmelz M. The impact of opioid-induced hyperalgesia for postoperative pain. Best Pract Res Clin Anaesthesiol 2007;21:65–83
4.Angst MS, Koppert W, Pahl I, Clark DJ, Schmelz M. Short-term infusion of the mu-opioid agonist remifentanil in humans causes hyperalgesia during withdrawal. Pain 2003;106:49–57
5.Singler B, Troster A, Manering N, Schuttler J, Koppert W. Modulation of remifentanil-induced postinfusion hyperalgesia by propofol. Anesth Analg 2007;104:1397–403, table of contents
6.Troster A, Sittl R, Singler B, Schmelz M, Schuttler J, Koppert W. Modulation of remifentanil-induced analgesia and postinfusion hyperalgesia by parecoxib in humans. Anesthesiology 2006;105:1016–23
7.Zhang Y, Eger EI II, Dutton RC, Sonner JM. Inhaled anesthetics have hyperalgesic effects at 0.1 minimum alveolar anesthetic concentration. Anesth Analg 2000;91: 462–6
8.Lange M, Redel A, Roewer N, Kehl F. Beta-blockade abolishes anesthetic preconditioning: impact on clinical applicability. Anesthesiology 2007;106:1062
9.Cortinez LI, Brandes V, Munoz HR, Guerrero ME, Mur M. No clinical evidence of acute opioid tolerance after remifentanil-based anaesthesia. Br J Anaesth 2001;87:866–9