Doppler‐guided fluid therapy in gynaecological surgery

We read with great interest the study by McKenny et al. 1 concerning the use of oesophageal Doppler in gynaecological surgery, which did not show a difference in patient outcome after fluid management guided by oesophageal Doppler compared with a control group. This research raises some methodological issues. A heterogeneous participant population was included in the study, one third of the patients undergoing non-oncological surgery and one third undergoing ovarian cancer surgery. Ovarian surgery is very different compared with uterine cancer surgery because of the pathophysiology of these diseases. Hysterectomy for cervical cancer is normally relatively quick, non-haemorrhagic, without major complications and with a very low mortality, and does not generally require advanced care including peri-operative goal-directed therapy 2. In contrast, cytoreduction surgery for advanced ovarian cancer is often of long duration, technically difficult and associated with postoperative morbidity and mortality of up to 40% and 6% respectively 3, 4. Ascites in patients with advanced ovarian cancer (class III and IV of the FIGO classification), secondary to chemical and cellular alterations in peritoneal membrane microvasculature 5 with albumin leakage, may lead to systemic hypovolaemia, complicating peri-operative fluid management. Length of hospital stay for simple hysterectomy is a few days, whereas two weeks is usually reported from referral centres for cytoreductive surgery of advanced ovarian cancer 6. The authors only provide the POSSUM score and duration of surgery to assess the illness severity of the patients. Data provided for these variables match better with low- to intermediate-risk surgery than they do with high-risk surgery. The FIGO score, the number of patients with ascites and thir nutritional status would have been interesting to define the population within the study. In addition, patients in the control group were fit for discharge after seven days when 11 days were scheduled and used for the power calculation, so we do not know if the results can be explained by the study's being underpowered or by a real lack of difference between the groups. In conclusion, we agree with the authors that further discrimination between patients may identify subgroups benefitting from goal-directed therapy. Based on the current study, we believe that the authors were not able to conclude that oesophageal Doppler-guided fluid administration in major gynaecological surgery did not reduce postoperative length of stay.