DISCUSSION
This study shows that ESPB may be applied for postoperative pain management of the PCNL, improves outcomes such as reducing the incidence of emergence agitation and preventing PEFR reduction comparing to preoperative values in recovery room. ESPB provided low VAS and DVAS values within the first 24 hours, and the mean SPO2values of the patients were found to be higher at the 24th hour compared to the control group.
Regional analgesia is an important element of successful postoperative pain-management since they reduce the consumption of opioids which have a high profile of side effects such as respiratory depression, nausea, vomiting, and slowing bowel movements 16. Trend in postoperative pain management has turned from epidural analgesia to the paravertebral, truncal and recently erector spinae plane block since it can be applied easily and has fewer complications17,18.
ESPB was defined by Forero et al. for the treatment of neuropathic chest pain in 2016 and has become popular as a postoperative pain treatment in many surgical procedures. It is a good alternative because of its relatively easy application compared to paravertebral blocks and it does not have complications such as pneumothorax, subarachnoid injection, urinary retention and hypotension.
There is a rapidly expanding literature on the efficacy of the ESPB in postoperative pain management of the PCNL 9-14. Our study may contribute to the relevant literature in several points. We ruled out potential confusion in the subjective evaluation of the patients by questioning the pain caused by the urinary catheter. We comprehensively investigated the pain using serial PEFR measurements and DVAS in association with its features that may be related to cough, respiration and mobilization in addition to the subjective and one-dimensional VAS scale. Additionaly we investigated the positive outcomes of the pain management with serial PEFR-SpO2measurements, assesing recovery agitation, mobilization, oral intake and discharge time.
After thoracic and upper abdominal surgeries, it has been shown that pain affects respiratory muscles and impairs respiratory functions. Pain can reduce vital capacity, may cause development of atelectasis and postoperative hypoxemia 19.
PEFR is an inexpensive, easily accessible respiratory function test that reflects vital capacity. PEFR value may decrease in the early postoperative period due to pain 19. In PNL surgery, Hosseini et al.4 investigated the effectiveness of peritubal ketamine infiltration and Imani et al.20also investigated the analgesic efficacy of ropivacaine infiltration and its effects on PEFR values. In these studies, it was shown that PEFR values decreased significantly in the early postoperative period after PNL, but pain management with peritubal infiltration did not affect PEFR values positively 4,20.
Although there are many predisposing factors in the pathogenesis of recovery agitation after urological surgery, a high level of relationship between pain and postoperative agitation has been reported7.
Our study showed that ESPB provides effective pain management and improves patient outcomes by preventing agitation and negative effects on early pulmonary functions.
For all that there are several limitations of our study. Patient controlled analgesia methods may be preferred instead of intermittent intravenous rescue tramadol analgesia. It can be assumed that this can reduce adverse outcomes of the intermittent bolus intravenous opioids. The exclusion of patients with ASA> II and the small sample size may have caused not to measure the effect of ESPB on length of hospital stay and mobilization time.