Compared with laparotomy, laparoscopic surgery is more suitable for less trauma and less complications. However, laparoscopic surgery is more prone to nausea and vomiting, postoperative pain still exists, many of them reach moderate pain, even severe pain. The nature of pain is mainly visceral pain, and even the pain is more severe than the surgical wound. Visceral pain is different from perceived physical pain. Patients may not feel well-defined pain, but produce a subjective abdominal discomfort that is difficult to say. However, such subjective abdominal discomfort can lead to anxiety, irritability, sweating and other negative emotions accompanied by nausea and vomiting, and even affect cardiovascular and respiratory functions [4]. Therefore, more and more attention should be paid to visceral pain after laparoscopic surgery.
Lovatisis et al. [5] reported that the incidence of severe pain after laparoscopic surgery can reach 10%. Poor postoperative pain control will affect the subjective experience and comfort of patients, thus prolonging the length of hospital stay, delaying postoperative rehabilitation, which is not conducive to the development of enhanced recovery after surgery (ERAS). Moreover, if the postoperative pain is not given adequate treatment, it may become a persistent chronic pain which is often ignored [6].
Patient controlled intravenous analgesia (PCIA) is easy to operate, and patients can add analgesic drugs according to their pain or not. It is safe and widely used in postoperative analgesia.
In 2017, the expert consensus on adult postoperative pain management proposed at the anesthesiology branch of Chinese Medical Association pointed out that strong opioids, namely narcotic analgesics, are the most commonly used drugs for the treatment of moderate to severe acute pain [8]. Opioid drugs are the most commonly used and effective postoperative analgesia, which mainly play the role of three types of receptors: µ, κ, δ [9, 10]. Although all three receptors have analgesic effect, the analgesic mechanism and analgesic effect are not the same due to the different distribution of receptors and different types of receptors. Activation of µ receptor mainly mediates analgesia above spinal cord, κ receptor mainly mediates analgesia and sedation at spinal level, δ receptor mainly couples with µ receptor in structure and regulates µ receptor in function The role of receptors [10, 11].
In fact, PCIA using opioids is indeed the most commonly used postoperative analgesia mode in clinical practice [12]. Sufentanil is commonly used in postoperative PCIA due to its very strong analgesic effect, which belongs to the central µ receptor agonist. It has satisfactory therapeutic effect on the body, but has limited effect on visceral pain [13]. However, its adverse reactions such as nausea and vomiting, respiratory depression, pruritus, tolerance and dependence are obvious, which limit the use of sufentanil to a certain extent. As an opioid receptor agonist antagonist, nabuprofen is also commonly used in postoperative PCIA, but its analgesic effect is weaker than sufentanil. However, in visceral pain model, κ - receptor agonist is the most effective opioid agonist, and its effect on u receptor is weak. Therefore, u receptor related nausea, vomiting, dizziness, headache, drowsiness, restlessness, pruritus, pruritus, nausea, vomiting, dizziness, headache, drowsiness, restlessness, pruritus, nausea, vomiting, dizziness, headache, drowsiness, restlessness, pruritus, nausea, vomiting, dizziness, headache The incidence of adverse reactions such as urinary retention decreased significantly * [14]. Based on the advantages and disadvantages of opioid agonists and antagonists, Cepeda MS [15] and firouzian a [16] pointed out that opioid agonists and antagonists can achieve stronger analgesia and reduce the adverse reactions of opioid drugs when the drug ratio is right. Therefore, it is very important to find a method of medication that does not affect the analgesic effect but also reduces the side effects of drugs. On the one hand, it is necessary to reduce visceral pain and minimize side effects.
Some studies have found that when an appropriate amount of nalbuphine combined with µ receptor agonists can produce good analgesic effect and reduce adverse reactions [17, 18]. Objective to evaluate the optimal dosage of nabufen and sufentanil for PCIA after gynecological laparoscopic surgery. The results showed that the analgesic effect of low-dose nalbuphine combined with sufentanil in group B did not change. However, the moderate dose and high-dose combination of nalbuphine and sufentanil significantly reduced the incidence of opioid related side effects and significantly enhanced the analgesic effect of opioids. This is consistent with the research results of Luo Chong [19] that 1 mg / kg of nabufen combined with 1 µ g / kg sufentanil for postoperative analgesia in patients with laparoscopic radical hysterectomy for cervical cancer can reduce the dosage of strong opioids, effectively relieve the pain of patients and have no other serious complications. However, compared with group C, there was no significant difference in analgesic effect and moderate dose of nabufen in group D, but the adverse reactions such as drowsiness and dizziness increased. This suggests that moderate dose of nabufen combined with sufentanil can be used as the best combination to prevent visceral pain after gynecological laparoscopic surgery.