In this study, we found that intravenous lidocaine infusion was as effective as dexmedetomidine in reducing the incidence of CRBD and lessening the requirement of rescue tramadol.
CRBD caused by intra-operative urinary catheterization is a common and distressing complication, and it is a recognized risk factor for postoperative emergence agitation [20]. However, CRBD is frequently neglected in clinical practice. Severe CRBD is usually accompanied by behavioral responses, such as a strong vocal response, shaking of arms and legs, and pulling out the urinary catheter. Thus, management of CRBD might be helpful in reducing postoperative emergence agitation, decreasing the workload of medical staff and improving patient comfort.
It has been reported that certain surgeries, such as bladder surgery, prostate surgery, urinary tract surgery, and lower abdominal surgeries (such as obstetric and gynecological surgery), which can cause bladder spasms, are more likely to be associated with CRBD [1, 21, 22]. Consideration that the surgeries are respected to the bladder or urethra can cause CRBD, in addition to the postoperative discomfort or pain originating from the surgical site, also seem to aggravate CRBD. In this investigation, patients undergoing open abdominal hysterectomy and hysteromyomectomy with the same-size catheter, we found a high incidence of CRBD up to 71.8%.
Dexmedetomidine is a selective a2-adrenoceptor agonist with analgesic, sympatholytic and sedative properties, without respiratory depression. Some studies have shown that dexmedetomidine decreases the incidence and severity of CRBD. The drug acts by M3 receptors [16, 17, 23]. In our study, we found that dexmedetomidine reduced the incidence of CRBD as well as the additional tramadol requirement for CRBD but not the different severity (mild, moderate, and severe) of CRBD. This difference may be explained by female gender and surgery properties in our study. Considering that dexmedetomidine was stopped at the end of the surgery, the postoperative sedative was higher in the dexmedetomidine group than in the other groups.
Intravenous lidocaine infusion has been demonstrated to decrease intra-operative opioid requirements, reduce postoperative pain, nausea and vomiting, ameliorate postoperative ileus, shorten the length of hospital stay [18, 19]. The mechanisms of systemically managing lidocaine include antagonism of NMDA receptors, anti-inflammatory effects on histamine, prostaglandins and kinins, suppressing C-afferent neuronal activity and neural excitability in dorsal horn neurons, and inhibiting spinal visceromotor neurons [18, 19, 24]. In this study, we found that intravenous lidocaine infusion had the similar effect of intravenous dexmedetomidine infusion on preventing of CRBD. We suggest that it may act though an anti-inflammatory effect and blockade of C-afferent neuronal activity.
There were some limitations in this study. First, since it was well known that lidocaine infusions and dexmedetomidine infusions could modulate all sorts of postoperative discomfort, but we did not evaluate the level of discomfort related not only to bladder discomfort, but also surgical pain or other discomfort. Second, this study was limited to the period of the drug metabolism in the immediate postoperative period, and failed to address patient bladder discomfort beyond 6 hours. Moreover, the severity of CRBD was recorded as three grades as mild, moderate, and severe which various descriptors were applied to these levels. But, if we used visual analog scale (VAS) or verbal rating scale (VRS) to evaluate CRBD, the severity of CRBD might had significant difference among the three groups in this study. Furthermore, we did not evaluate the efficacy of all types of surgery, different surgeries have different degrees of interference. Therefore, further studies are warranted.