Preoperative sleep disturbance and anxiety worsen postoperative pain for patients undergoing surgeries. Research indicates that a significant proportion of patients, ranging from 8.8% to 79.1%, experience disturbances in sleep or anxiety prior to surgery. These preoperative issues have been shown to have lasting and intricate effects on postoperative pain, fatigue, and depression. Therefore, it is imperative for clinical doctors to promptly identify preoperative sleep disturbances and anxiety in order to offer appropriate support to patients.

Colorectal cancer is the fifth leading cause of death in China, with nearly 40% of patients experiencing insomnia before surgery, consistent with our previous studies. A case-control study demonstrated a protective association between improved sleep quality and relief of postoperative pain in colorectal cancers. Furthermore, individuals undergoing laparoscopic colorectal surgery showed a higher likelihood of experiencing visceral pain compared to somatic pain. Acute visceral pain has the potential to progress into chronic visceral pain, resulting in behavioral manifestations such as anxiety, fear, and depression, which may persist and exacerbate into enduring chronic pain, ultimately impacting the individual's quality of life. Currently, studies have shown that disturbed preoperative sleep has become a significant predictor of both acute and chronic postoperative pain. Therefore, finding effective interventions to promote preoperative sleep is a continuing consideration for clinicians.

Pharmacological intervention is the primary approach for preoperative sleep disturbances or anxiety. Finding appropriate drug is a challenge that needs to be solved in the clinical practice. There is currently a lack of evidence-based medical guidelines regarding pharmacologic interventions for preoperative sleep disturbances and anxiety. Research has indicated that zolpidem can enhance sleep quality in patients prior to surgery, decrease the need for analgesics during the procedure, and alleviate postoperative pain. Nevertheless, there is a demand for agents that possess both short-term hypnotic and anxiolytic properties, whereas zolpidem solely exhibits hypnotic effects. Midazolam, a short-acting benzodiazepine, is often used before anesthesia for its short-term hypnotic and anxiolytic effects. Studies have found that midazolam oral solution is safe and effective for short-term use in clinical pre-surgical settings. There are no studies on using oral midazolam solution to improve sleep and reduce anxiety in colorectal cancer patients before surgery. Our previous research found that a dose of 7.2mg can effectively induce sleep with minimal side effects in 50% patients before surgery.

In summary, the present study intends to carry out a prospective,randomized,double-blind,placebo-controlled clinical study to investigate the hypothesis that preoperative oral midazolam solution could reduce acute postoperative pain, promote early recovery, and reduce the risk of chronic pain in patients with poor sleep or anxiety before colorectal cancer surgery. It is postulated that the potential benefits of preoperative oral midazolam solution may be attributed to decreased stress levels, and lowered inflammation markers.