He et al. BMC Urol (2021) 21:72 https://doi.org/10.1186/s12894-021-00841-4 RESEARCH ARTICLE Open Access Efects of irrigation fuid temperature during fexible ureteroscopic holmium laser lithotripsy on postoperative fever and shivering: a randomized controlled trial Yue He1,2*, You‑Gang Feng1, Jun He1, Bo Liang1, Ming‑Dong Jiang1, Jun Liu1, Yong‑Ming Kang1, Li‑Ping Ma3, Qin Zhang3, Qi‑Jia Peng3, Tao Yang1, Yao Liu3, Li Luo4 and Min Zhang4 Abstract Background: Flexible ureteroscopic holmium laser lithotripsy is used to treat urinary tract calculi, but postopera‑ tive complications include shivering, fever and infection. To investigate the efects of irrigation fuid temperature on postoperative complications. Methods: This randomized controlled trial included 120 consecutive patients undergoing fexible ureteroscopic holmium laser lithotripsy at the Urology Department, Suining Central Hospital, Sichuan, China between January 2017 and July 2019. Patients were randomized 1:1:1 into three groups (17 °C, 27 °C or 37 °C). Primary outcome was fever incidence (body temperature > 37.5 °C) within 48 h after surgery. Secondary outcomes included shivering incidence during recovery from anesthesia, white blood cell count (WBC), serum procalcitonin (PCT) and incidence of sus‑ pected infection (temperature > 38.5 °C and PCT > 0.5 µg/L). Results: There were 108 patients, (17 °C group, n 36; 27 °C group, n 35; 37 °C group, n 37), received fexible ureteroscopic holmium laser lithotripsy and analyzed.= Age, gender distribution,= body mass= index, ASA grade, stone burden, preoperative creatinine, preoperative core temperature and irrigation fuid volume did not difer signifcantly between groups. 17 °C, 27 °C and 37 °C groups exhibited signifcant diferences in the incidences of postoperative fever (38.9% vs. 17.1% vs. 13.5%) and shivering (22.2% vs. 5.7% vs. 2.7%) (p < 0.05 for all pairwise comparisons). There was no signifcant diference of WBC, PCT and incidence of suspected infection in 37 °C or 27 °C group compared with 17 °C group. One case each of fash pulmonary edema and bleeding occurred in 37 °C group. Conclusion: Warming the irrigation fuid can reduce the incidence of postoperative fever and shivering, but further studies are needed to determine the optimal temperature. Trial registration The trial was registered at the Chinese Clinical Trials Registry and allocated as ChiCTR2000031683. The trial was registered on 07/04/2020 and this was a retrospective registration. Keywords: Irrigation fuid, Temperature, Flexible ureteroscopic holmium laser lithotripsy, Calculi, Holmium: YAG laser Background *Correspondence: [email protected] Calculi can develop in the urinary tract when the urine 1 Department of Urology, Suining Central Hospital, No. 127 Desheng W. Rd., Chuanshan District, Suining City 629000, Sichuan Province, People’s becomes supersaturated with a mineral, leading to the Republic of China formation of crystals comprised of calcium oxalate, cal- Full list of author information is available at the end of the article cium phosphate, uric acid or other substances [1]. Te © The Author(s) 2021. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://crea‑ tivecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdo‑ main/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. He et al. BMC Urol (2021) 21:72 Page 2 of 8 prevalence of urinary calculi is higher in developed coun- short-term postoperative complications including fever tries than in developing countries and has been estimated and shivering. to be around 9% in the USA and 4% in China [2]. Fac- tors associated with an increased risk of urinary calculi in Methods adulthood include male gender, obesity and diabetes mel- Study design litus [1]. Urinary stones often present acutely with pain, Tis was a randomized controlled trial conducted at infection or hematuria, necessitating treatment. A variety the Department of Urology, Suining Central Hospital, of medical [3] and surgical [4, 5] therapies are available Sichuan, China between January 2017 and July 2019. Te for the treatment of urinary calculi, including stone frag- Ethics Committee of Suining Central Hospital, Sichuan mentation by lithotripsy [6]. Province, P.R. China approved the study. All patients read Te development of endoscopic technology and litho- and understood written information describing the study tripsy techniques for the treatment of urinary calculi has aims and protocol, and all patients signed consent forms led to traditional open surgery being replaced by endo- agreeing to participate in this clinical research. scopic procedures [7]. Ureteroscopes introduced via the urethra can reach upper urinary tract calculi in the ure- Patients ter, renal pelvis and calyces, permitting holmium laser Participants were enrolled using the following inclusion lithotripsy to be carried out as a treatment [8]. Te latest criteria: (1) age 18–70 years; (2) American Society of recommendations of the European Association of Urol- Anesthesiologists (ASA) grade I or II [21]; (3) diagnosis ogy, which were published in 2019, recommend fexible of unilateral proximal ureteral calculi and/or renal cal- ureteroscopic lithotripsy as the frst-line surgical treat- culi made by computed tomography (CT); (4) diameters ment option for proximal ureteral/renal calculi with a of all calculi were < 20 mm; and (5) total stone burden diameter < 20 mm [9]. However, postoperative compli- was < 360 mm2. Te exclusion criteria were as follows: (1) cations occur in 2.5–6.7% of patients after ureteroscopic thyroid disease or dysautonomia; (2) bilateral upper uri- stone treatment [10–13], and fever is the most common nary tract stones scheduled to be treated simultaneously postoperative complication of ureteroscopic holmium during surgery; (3) preoperative fever; (4) urinary tract laser lithotripsy [10, 11, 14–18]. Terefore, there is great infection when included in the trial; (5) hydronephro- interest in identifying methods to reduce the incidence of sis > 3 cm on ultrasound; (6) ureteral stenosis. fever after ureteroscopic holmium laser lithotripsy. Te use of irrigation fuid is essential during tran- Randomization and blinding surethral endoscopic surgery. Flexible ureteroscopic Patients were randomized 1:1:1 to 37 °C group, 27 °C lithotripsy is often performed with continuous saline irri- group or 17 °C group. Te random sequence and group- gation through the working channel to improve the vis- ing sequence were generated using the random function ibility when an instrument is inserted, particularly during in Excel (Microsoft Corp., Redmond, WA, USA), and the stone dusting or when a small venous bleed occurs. generated random sequence was put into sequentially Warming the irrigation fuid has been shown to reduce coded, sealed and opaque envelopes. Te envelopes were the incidence of hypothermia and shivering during tran- kept by an investigator (TY) who did not participate in surethral resection of the prostate (TURP) [19]. Fur- the recruitment of patients, intervention or outcome thermore, the use of isothermic irrigation fuid can help evaluation. Te sealed envelope was brought into the to maintain normal body temperature and avoid hypo- operating room with the patient and opened by the anes- thermia during percutaneous nephrolithotripsy (PCNL) thesiologist and nurse who were in charge of setting the [20]. However, the efects of irrigation fuid temperature temperature of the irrigation fuid during surgery. during fexible ureteroscopic holmium laser lithotripsy on body temperature and the postoperative incidences Intervention of shivering, fever, infection and other complications One week before the procedure, a ureteral stent was remain unknown. placed routinely to dilate the ureter. Te irrigation fuid We hypothesized that increasing the temperature of used during surgery was sterile physiological saline. Te the irrigation fuid during fexible ureteroscopic holmium surgical nurse (MLP, ZQ, PQJ), who was responsible for laser lithotripsy would reduce the incidence of shiver- setting the temperature of the irrigation fuid during the ing during recovery from anesthesia and fever during operation, placed the irrigation fuid into a medical incu- the 2-day period after the procedure. Terefore, the aim bator with a pre-set temperature (37 °C, 27 °C or 17 °C) of this randomized controlled trial was to investigate the 6 h before the procedure. Te temperature of the irriga- efects of irrigation fuid temperature during fexible ure- tion fuid was 37 °C for patients in 37 °C group, 27 °C for teroscopic holmium laser lithotripsy on the incidence of patients in 27 °C group, and 17 °C for patients in 17 °C He et al. BMC