Effect of Dexmedetomidine and Esketamine on Catheter-related Bladder Discomfort

Urethral catheterization is commonly used during and after surgery. However, patients with indwelling urinary catheters often present with catheter-related bladder discomfort (CRBD) after awakening from anesthesia. CRBD is characterized by pain and discomfort in the suprapubic area or symptoms like overactive bladder, characterized by frequent and urgent urination, with or without acute incontinence. The incidence of CRBD is relatively high, ranging from 47% to 90%. The development of CRBD not only reduces patients' perioperative satisfaction, but also increases the incidence of postoperative complications, affects patients' postoperative rehabilitation, and prolongs the length of hospital stay. It also increases the workload of medical staff.

The occurrence of CRBD is affected by many factors, such as gender, size of urinary tube, and type of surgery. Studies show that the use of ≥18F catheter increases the incidence of CRBD. After transurethral surgery, such as transurethral resection of bladder tumor (TUR-Bt), transurethral resection of prostate (TURP), and transurethral holmium laser resection of prostate (HoLRP), a 20F catheter is often required for bladder irrigation; the catheter carrying time may be extended for bladder perfusion. Therefore, the incidence of CRBD is higher after such operations.

Dexmedetomidine is a highly selective α2 receptor agonist with analgesic, anxiolytic, and sedative effects. Several randomized trial confirmed that intraoperative use of 0.3-1.0 μg/kg dexmedetomidine reduces the incidence and severity of postoperative CRBD, and the effect persists up to 6 hours after surgery. Ketamine is a non-competitive N-methyl-D-aspartate receptor antagonist and produces analgesic and anti-hyperalgesia effects. A recent meta-analysis found that subanesthetic doses of ketamine (0.25 mg/kg or 0.5 mg/kg) reduce the severity of CRBD within 1-2 hours after surgery and the incidence of CRBD within 2-6 hours after surgery. Esketamine is the S-enantiomer of racemic ketamine and has a higher affinity for NMDA receptors; it is twice as potent as racemic ketamine.

The investigators hypothesize that the combination of dexmedetomidine and esketamine may improve the efficacy in preventing CRBD. This 2x2 factorial trial is designed to observe the effect of dexmedetomidine, esketamine, and dexmedetomidine-esketamine combination on the occurrence of CRBD in patients following transurethral urological surgery.

Inclusion criteria

• Aged 18 years or above;
• Scheduled to undergo transurethral bladder or prostate surgery (including transurethral resection of bladder tumor, transurethral resection of prostate, and transurethral thulium laser prostatectomy) under general anesthesia;
• Required postoperative retention of a three-chamber urinary catheter.

Exclusion criteria

• Indwelling urinary catheters or chronic analgesic therapy for ≥1 month before surgery;
• Uncontrolled hypertension before surgery (resting ward systolic pressure >180 mmHg or diastolic pressure >110 mmHg);
• Severe bradycardia (heart rate ≤50 beats per minute), sick sinus syndrome, or atrioventricular block of degree II or above without pacemaker, or having myocardial infarction, severe heart insufficiency (New York Heart Association class ≥3), or tachyarrhythmia within a year;
• Preoperative history of schizophrenia, epilepsy, Parkinson's disease, myasthenia gravis, or intracranial hypertension;
• Preoperative history of hyperthyroidism and pheochromocytoma;
• Inability to communicate due to coma, severe dementia, or language barrier before surgery;
• Severe liver dysfunction (Child-Pugh grade C), severe renal dysfunction (receiving dialysis before surgery), or Amercian Society of Anesthesiologists classification ≥IV;
• Scheduled admission to the intensive care unit with endotracheal intubation after surgery;
• Other conditions that are considered unsuitable for study participation.