We would like to thank Dr Gong et al.1 for their interest in our article2 and their observations. In response to their questions and comments, we would like to mention the following aspects.
First, regarding the type of solution for perioperative fluid replacement, none of the patients in our study received colloids during the study observation period. The type of replacement solution was crystalloid (Ringer's solution). There were not significant differences between study groups in mean amounts of crystalloid administration during the intraoperative and postoperative periods (i.e. during the first 24 h): 3815 ± 812 ml in the total intravenous anaesthesia group and 3925 ± 717 ml in the isoflurane group. Moreover, none of the patients received less than 2500 ml or more than 5500 ml of crystalloid during the first 24 h, as recommended. Large volumes may significantly influence the immune response.3,4 Prophylactic antibiotics were administered to all patients according to national and international guidelines and included intravenous metronidazole 0.5 g and ceftriaxone 2 g 60 min before induction.5 Standard mechanical bowel preparation was done in both study groups. We agree with assertion of Dr Gong et al.1 that antibiotics may influence the immune response and infection rate, but in our study groups, there were no differences in the dose and duration of antibiotic prophylaxis.
As to the parenteral nutrition, we would like to mention that none of our patients received parenteral nutrition before, or immediately after, surgery. Early oral fluids and oral nutritional supplements were started the day of surgery until normal food intake was achieved as suggested in guidelines.6 All our patients underwent elective surgery and none suffered from malnutrition.
Second, we agree with Dr Gong et al.1 that the type of surgery is important for the surgical stress and immune response. This is why in our study, only curative colonic and rectal resections with anastomosis were included. Lower rectal cancer patients were not considered because of the high risk of abdominoperineal resection with definitive colostomy. We did not mention this specifically as an exclusion criteria, but the type of surgery was mentioned in Table 1 and unintended rectal amputations were excluded from the study as shown in the study flow chart. We also mentioned in our study that surgery was performed by the same surgical team in all cases.
In response to the observation regarding details of surgical techniques, we may specify that rectal resection with partial mezorectal resection for superior rectal and rectosigmoid tumours was done in five patients (one superior rectal and four rectosigmoid) in the total intravenous anaesthesia group and in seven patients (two superior rectal and five rectosigmoid) in the isoflurane group. In each group, one patient underwent total rectal resection with coloanal anastomosis and temporary ileostomy for mid-rectal cancer. As shown in Table 1, there were no significant differences in surgical procedures between the study groups.
Third, we also agree with Dr Gong et al.1 that carcinoembryonic antigen is an important marker for prognosis and postoperative monitoring of these patients. However, due to a large interindividual variability in carcinoembryonic antigen levels, an accurate relationship between carcinoembryonic antigen and interleukin levels cannot be established. In our study groups, median carcinoembryonic antigen levels were 2.9 (range, 0.5 to 46.8) ng ml−1 in the total intravenous anaesthesia group and 3.5 (range, 1.5 to 39.5) ng ml−1 in the isoflurane group. Moreover, we have excluded from the study patients with pre and intraoperative signs of metastasis and organ invasion. Most of the tumours in our study were adenocarcinoma without significant differences between groups. Moderately differentiated adenocarcinomas were present in 46.7% of patients in both study groups. Well differentiated adenocarcinomas were present in 20% of patients in the total intravenous anaesthesia group and in 23.3% of patients in the isoflurane group. Poorly differentiated adenocarcinomas were present in the rest of the patients in both study groups.
Finally, we regret that accidentally, in the Table 1, three instead of two patients were reported in the ASA III subgroup; we thank Dr Gong et al.1 for highlighting this mistake.
In conclusion, we agree with most issues raised by Dr Gong et al.1 and we have tried to clarify the less clear aspects of our article. However, we would like to stress that there were no significant differences in any of the above-mentioned aspects between study groups.
Acknowledgements relating to this article
Assistance with the letter: none.
Financial support and sponsorship: none.
Conflicts of interest: none.
1. Gong L, Dong C, Ouyang W. Influence of total intravenous anaesthesia and isoflurane on plasma interleukin concentrations after colorectal cancer surgery. Eur J Anaesthesiol
2. Margarit SC, Vasian HN, Balla E, et al. The influence of total intravenous anaesthesia and isoflurane anaesthesia on plasma interleukin-6 and interleukin-10 concentrations after colorectal surgery for cancer: a randomised controlled trial. Eur J Anaesthesiol
3. Rhee P, Wang D, Ruff P, et al. Human neutrophil activation and increased adhesion by various resuscitation fluids. Crit Care Med
4. Lee CC1, Chang IJ, Yen ZS, et al. Effect of different resuscitation fluids on cytokine response in a rat model of hemorrhagic shock. Shock
5. Romanian Ministry of Health. Antibiotic prophylaxis guidelines in surgery [Internet] 2010 [updated 2013 Dec 13; cited 2014 Sept 17]. Available from: http://www.ms.ro/documente/Anexa%20-Ordin%20-ghid%20de%20profilaxie%20antibiotica%20in%20chirurgie_863_1718.pdf
6. Gustafsson UO, Scott MJ, Schwenk W, et al. Guidelines for perioperative care in elective colonic surgery: Enhanced Recovery After Surgery (ERAS) Society recommendations. Clin Nutr