The effect of analgesic method on postoperative pulmonary function tests and neuroendocrine response in patients undergoing thoracic surgery with general anesthesia

Introduction: Postoperative thoracotomy pain is one of the most severe and may occur due to retraction, resection or rib fracture, disarticulation of the costovertebral joints, intercostal nerve damage and/or pleural irritation with a chest tube. Neuraxial block techniques (thoracic epidural, paravertebral, erector spina plane, intercostal block) applied to this region aim to prolong the duration of postoperative analgesia and increase the quality of anesthesia as well as reducing anesthetic and opioid consumption (during and after surgery) with all the positive results, including early mobilization and reduction in the incidence and prolongation of atelectasis in the postoperative period. Inadequate pain management after thoracotomy leads to various pulmonary complications. Surgical injury induces a stress response with the activation of endocrine, metabolic and immunological mediators aimed at restoring hemostasis and inducing tissue repair. In our study, we aimed to determine the effect of analgesic method on postoperative pulmonary function tests, stress hormone and proinflammatory response in cases undergoing elective thoracotomy surgery. Patients and Method: Between June 2021 and January 2022, 72 patients with ASA I-II risk score, aged 18-75, who were scheduled for elective thoracotomy surgery at Akdeniz University Medical Faculty Hospital, were included in the study without gender discrimination. After the patients were informed about the effects and possible complications of ESP block and conventional analgesics; the choice of analgesic method was left to the patient. 36 patients who chose the ESP block application were included in the Block group, and 36 patients who did not choose the block application and chose only IV analgesic use were included in the control group. Demographic characteristics of the patients, BMI, comorbidities, type of surgery, duration of surgery, amount of surgical incision, intraoperative opioid consumption, total analgesic amount in 48 hours, rescue analgesic amount, VAS scores, amount of fentanyl used in intensive care, extubation times from intensive care and hospital discharge times were recorded. Pulmonary function tests of the patients were performed. Blood samples were taken to measure IL-6, TNF-α, cortisol, CRP, insulin and blood glucose levels preoperatively, at the 3rd hour after postoperative extubation, and at the 24th postoperative hour. While evaluating the findings, they were evaluated using the SPSS 23.0 statistical program for statistical analysis. For statistical significance, the p value was determined to be less than 0.05. Results: The median age of 72 patients included in the study was 58 (IQR=43- 65), 53 (IQR=39-63) years in the erector spina plan (ESP) block group and 60 (IQR=57-67) years in the control group. The age of the patients in the block group was found to be significantly lower than those in the control group (p=0.007). The rate of male patients in both groups was 55.6%; the rate of female patients is 44.4%. While 75% of the patients in the ESP group had an ASA score of 1, 69.4% of the patients in the control group had an ASA score of 2, which was statistically significant (p<0.001). Educational status, body mass index (BMI) and BMEPS (The Brief Measure of Emotional Preoperative Stress) test of the patients were statistically similar. Intraoperative remifentanil use was calculated as 0.097 mcg/kg/min in the ESPB group and 0.111 mcg/kg/min in the control group, and it was found to be statistically significantly lower in the block group (p=0.008). While the amount of fentanyl used in the patients from the end of the operation to extubation was 336.11±138.16 mcg in the control group, 187.5±144.61 mcg was used in the block group, and it was found to be significantly lower in the block group (p<0.001). The time to extubation was similar in both groups. VAS values at rest and coughing at the 3rd hour after extubation, 24th and 48th hours postoperatively were found to be significantly lower in the block group than in the control group (p<0.001). While 5 mg of morphine was administered to 3 patients in the ESP group between 0- 3 hours after extubation, paracetamol was administered to 7 patients and 5 mg of morphine to 6 patients in the control group, these differences were statistically significant (p=0.006). Dexketoprofen use was less in the block group than in the control group between the 3rd and the postoperative 24th hours after extubation (p=0.001). In this process, no additional analgesics were used in the block group, while paracetamol was used in 4 patient, 5 mg morphine was used in 4 patients in the control group, and intercostal block was performed in 1 patient. The rate of not using additional analgesics was found to be significantly higher in the block group than in the control group, and the use of paracetamol and morphine was significantly higher in the control group than in the block group (p=0.002). Dexketoprofen use between 24-48 hours postoperatively was also less in the block group than in the control group (p=0.039). Pulmonary function tests were performed preoperatively, at the 3rd hour after extubation, at the postoperative 24th hour, and at the postoperative 48th hour, and PFT results were found to be similar in both groups (p>0.05). All laboratory parameters (IL-6, TNF-α, cortisol, CRP, insulin and blood glucose) at the 3rd hour after extubation were found to be statistically similar between the groups (p>0.05). However, there was a decrease in IL-6 and TNF-α levels in the ESPB group compared to the preoperative period, while an increase in TNF-α concentrations and an insignificant increase in IL-6 concentrations were observed in the control group. Cortisol level at the postoperative 24th hour was 12.48±9.04 µg/dl in the block group and 18.01±8.4 µg/dl in the control group (p=0.009). The CRP level at the postoperative 24th hour was 112.05±46.48 mg/dl in the block group and 155.98±59.31 mg/dl in the control group (p=0.001). The blood glucose value at the postoperative 24th hour was 128(112-144.5) mg/dl in the block group and 158.5 mg/dl (121.5-201) in the control group (p=0.015). Cortisol, CRP and blood glucose values were found to be significantly lower in patients in the block group compared to the patients in the control group. Other laboratory parameters at the postoperative 24th hour were similar between the groups (p>0.05).