This prospective randomized study was carried out from November 2019 to May 2020 in Tanta University Hospitals. The trial followed the CONSORT 2010 statement guidelines for conducting a randomized controlled trial.
Ethics approval and consent to participate:
This study was approved by the University's Institutional Review Board (IRB0010038) and written informed consent was obtained from all subjects participating in the trial. The trial was registered prior to patient enrollment. Trial registration (PACTR, No: PACTR201910617459894, Registered 24 October 2019, https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=9479).
Consent for publication:
Seventy-five female patients, aged 30-60, American Society of Anesthesiologists (ASA) physical status Classification I– II, and scheduled for elective laparoscopic hysterectomy were included in the study. The trial followed the CONSORT 2010 guidelines for conducting a randomized controlled trial.
The exclusion criteria included patient refusal, severe respiratory or cardiac disorders, hepatic or renal insufficiency, allergy to any of the study drugs, body mass index >35 kg /m2, uncontrolled diabetes, and use of any drug that might affect the immunity as chemotherapy or hormonal treatment.
Sample size calculation:
Based on previous study, we hypothesized that attenuation in cytokine concentration would be at least 30% 6 h after intravenous dexmedetomidine infusion intraoperative. Therefore, twenty-one patients are required in each group at an alpha value of 0.05 and 90% power of the study. To overcome the dropped-out cases, 25 patients are included in each group.
Patients were randomized into three equal groups (25 patients each) using computer-generated random numbers concealed in sealed opaque envelopes indicating the group of assignment. In group C (control group), patients received general anesthesia (GA) only while in group K (ketamine group), received racemic ketamine, and those in group D (dexmedetomidine group) received dexmedetomidine.
In the preoperative preparatory room, an intravenous line was established; midazolam 2 mg intravenous was given to all patients. A venous blood sample was withdrawn to determine base line values of tumor necrosis factor‑alpha (TNF-α), interleukin-6 (IL-6), C- reactive protein (CRP) which were used as inflammatory biomarkers.
On arrival to the operating theater, monitoring was applied to all participants including electrocardiogram (ECG), non- invasive blood pressure (NIBP) and pulse oximetry (Cardiocaps/5; DatexOhmeda, Helsinki, Finland). Baseline values of heart rate (HR) and mean arterial pressure (MAP) were recorded.
For all patients, GA was induced with fentanyl 1µg /kg, propofol 2mg/kg and cisatracurium 0.15 mg/kg. After endotracheal intubation, capnography was added to the previous monitoring. Patients in group K received racemic ketamine 0.25 mg/kg as intravenous bolus dose over 10 min then intravenous infusion at rate of 250 µg · kg-1 · h-1 While patients in group D received dexmedetomidine 1 µg/kg as intravenous bolus dose over 10 min then intravenous infusion at rate of 0.5 µg · kg-1 · h-1.
Bolus dose of either drugs was given before the skin incision followed by continuous infusion according to the group of assignment. Anesthesia was maintained by isoflurane 1.5-2% in 50% oxygen and cisatracurium 0.03mg/kg as required, and ventilator settings were adjusted to keep EtCO2 between 35 and 40 mmHg.
After completion of the surgical procedure, ondansetron 4 mg intravenous was given and tracheal extubation was done after reversal of neuromuscular block and fulfillment of extubation criteria.
All patients were transferred to the post-anesthesia care unit (PACU) and they were transferred to surgical ward according to modified Aldrete score (if score is ≥9)
Our primary outcome was to assess inflammatory biomarkers TNF-α, IL-6, CRP at the following points: T1; base line before induction of anesthesia, T2; 6 hours after injection of the study drugs, T3; 24 hours after injection of the study drugs.
Venous blood samples were collected in into EDTA tubes. Blood samples from each subject were collected simultaneously over 10–20 minutes. Samples were immediately placed on ice and centrifuged at 2000 g for 10 minutes and then plasma was frozen and stored at −70C° until further analyzes which were performed within 10 days after collection. The sandwich ELISA (enzyme-linked immunosorbent assay) method using commercially available tests (Quantikine ELISA Kit, R&D Systems, Minneapolis, USA) was applied for determination of TNF‑α, IL‑6, CRP levels. The absorbance measurements were performed with a use of the photometer for microplates Elx 800 by Bio-Tek Instruments (USA). The absorbance values were read for the wavelength of λ = 450 nm with Λ correction 540 or 570 nm. The absorbance was converted into concentration units based upon a standard curve.
Secondary measurements were MAP and HR, which were measured at the following points: baseline before induction of anesthesia (T0), immediately after intubation (T1), immediately after end of bolus dose of the study drugs (T2), then every 10 min until the end of surgery. Recovery time was measured from discontinuation of anesthesia and reversal of muscle relaxant until transfer to PACU. Any adverse effects like postoperative nausea and vomiting (PONV), Hypotension (MAP < 65 mmHg), bradycardia (HR< 50 beat/min), over-sedation, and psychomimetic change as agitation, hallucinations, or vivid dreams up to 24 h after the surgery) were recorded.
Data were fed to the computer and analyzed using IBM SPSS software package version 20.0. (Armonk, NY: IBM Corp). The Kolmogorov- Smirnov test was used to verify the normality of distribution of variables; Comparisons between groups for categorical variables were assessed using Chi-square test (Fisher or Monte Carlo). ANOVA was used to compare more than two groups for normally distributed quantitative variables and followed by Post Hoc test (Tukey) for pairwise comparison. ANOVA with repeated measures and Post Hoc test (adjusted Bonferroni) was assessed for comparison between different periods Significance of the obtained results was judged at the 5% level.