The efficacy and dose optimization of sufentanil postoperative patient controlled analgesia after moderate surgery: a single center, randomized, double-blinded trial v1
Authors: Zhen Luming , Wei Haidong 
Published: January 2018

As the “comfort medicine” being developed, pain control rises as a focused issue between patients and physicians. The relief of acute postoperative pain is emphasized among anesthesiologists and surgeons [1-4]. Surgeries injured local tissue, leading to release of histamine and inflammatory factor like bradykinin, prostaglandins, serotonin, and neurotrophic factors etc., which result in the activation of the peripheral nociceptive receptor. The nociceptive signal is transmitted through A δ or C fibers to the dorsal horn of spinal. After serials of complicated modulation, the nociceptive signal is sensed by brain. If the acute pain was not treated properly and in time, the sympathetic nerve system would be stimulated, resulting in increased oxygen consumption of the myocardium, decreased oxygen supply to the myocardium, ultimately increase of perioperative heart ischemia or myocardial infarction. Other harm due to the high tense of sympathetic system is that the recovery of the gastrointestinal function would be delayed, even ileus. Inadequate treatment of the postoperative pain will result in shallow rapid respiration, reluctant to coughing, and eventually increase of the pulmonary complications. It is recognized that lack of postoperative pain control will lead to some undesired influences like the clinic experience of the patients, postoperative rehabilitation, prolonging of the hospital stay, increase of probability of readmission, or even the increased risk of cerebrovascular and cardiovascular events or deaths [5-7]. Besides, if the acute pain was not treated effectively and properly, not only it would severely influence the quality of life, a huge mental distress, but also might develop to chronic pain or neuropathic pain. And it was observed that after surgery, the degree of pain was related to subsequently developed chronic pain [8]. Therefore, in the daily practice of anesthesia, pain free becomes as our main pursuit. The management of postoperative pain consists of multiple models and methods. The old ways relied on the intramuscular injection of analgesics by nurses. While the recent decades, the patient controlled analgesia had shown plenty of advantages like effective pain relief, better medical benefits, the participation of patients and satisfaction. The patient controlled intravenous analgesia (PCIA) as one of the main parts of self-analgesia has now become very prevalent during the postoperative period. In the past morphine or fentanyl was used as the main drug for pain control in PCIA. But these two narcotics are inappropriate for continuously infusion because of the pharmacokinetics which might lead to accumulation of drugs and more side effects. And patients would be reluctant to press if the pain was not well relieved. Sufentanil is one of new narcotics deprived of morphine with stronger efficacy and longer duration of effect time. Sufentanil has more stable pharmacokinetics than morphine or fentanyl and more suitable for long duration infusion. Moreover, it has multiple administration routine like intravenous, intranasal, sublingual administration, all of which had been shown safe and effective in postoperative pain control [9-11]. But there are still some deficiencies in the use of sufentanil for postoperative pain like inadequate analgesia which patients complaining of unbearable pain and demanding more analgesics, or over analgesia which results in over sedation or respiratory depression. The dose and efficacy of sufentanil in PCIA is unclear and a proper reference of sufentanil in PCIA is still lacking. Therefore, its very necessary to assess its analgesic effect and ultimately to optimize the use of sufentanil in PCIA. And we conduct this study to observe the use of sufentanil in PCIA after moderate surgery, and to determine the optimal dose of sufentanil with best pain relief and minimal side effects.