Ketamine versus Dexmedetomidine Sedation in the Attenuation of Surgical Stress Response and Postoperative Pain: A Retrospective Study

Introduction: Surgical procedures cause stress response in the body. This response involves endocrine, metabolic, haematologic and immunologic reactions. Ketamine has an anti-proinflammatory effect as limiting exacerbation of systemic inflammation. Likewise, dexmedetomidine has anti-stress, sedative, analgesic actions and decreases surgical stress response and leads to better stable haemodynamic properties. Aim: To compare effects of ketamine, dexmedetomidine and determine correlation between postoperative pain scores and serum C-reactive protein on surgical stress response. Materials and Methods: Electronic records of 121 patients who had inguinal hernia repair were analysed retrospectively. Patients' age, sex, operation time, sedation drug, preoperative and postoperative C-Reactive Protein (CRP) and leukocyte levels, postoperative visual analogue scale scores were recorded. Normality of the variables were analysed by Kolmogorov-Smirnov test and homogeneity was analysed by Levene's test. Mean tests were compared using independent t-test if data distribution was normal or using nonparametric Mann-Whitney U-test if data were not distributed normally. Pearson's correlation was used to analyse correlation between VAS score and postoperative CRP level. The p-value <0.05 was considered statistically significant. Results: Postoperative mean CRP level was 42.3 +/- 9 mg/dL in ketamine group and 65.4 +/- 6.6 mg/dL in dexmedetomidine group. Mean visual analogue scale at postoperative 24th hour was 2.6 +/- 0.8 in ketamine group and 3 +/- 0.7 in dexmedetomidine level. These differences were statistically significant (p<0.05). Leukocyte counts were similar between groups. There was a moderate positive correlation between postoperative 24th hour CRP levels and pain scores. Conclusion: Ketamine was found to be more effective then dexmedetomidine at attenuation of surgical stress response. Postoperative serum CRP level was correlated with postoperative pain scores.