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Room Temperature Versus Warm Irrigation Fluid Used for Patients Undergoing Arthroscopic Shoulder Surgery: A Systematic Review and Meta Analysis
ORIGINAL ARTICLE
Room Temperature Versus Warm Irrigation Fluid Used for Patients Undergoing Arthroscopic Shoulder Surgery: A Systematic Review and Meta Analysis Youbin Lin, MD, Chunbin Zhou, MD, Zhaoyong Liu, MD, Kezhou Wu, PhD, Shubiao Chen, MD, Weihao Wang, MD, Yelong Chen, MD, Hu Wang, MD Purpose: The aim of this study was to analyze whether warm irrigation fluid could reduce postoperative adverse effects in patients undergoing arthroscopic shoulder surgery compared with room temperature irrigation fluid. Design: A systematic review and meta-analysis of clinical trials was performed. Methods: A computerized search of electronic databases was performed. The inclusion criteria were studies comparing the clinical effects of room temperature and warm irrigation fluid on patients undergoing arthroscopic shoulder surgery. Findings: Warm irrigation fluid reduced the degree of core body temperature drop and the incidence of hypothermia. A statistically lower incidence of shivering also occurred in the warm irrigation fluid group. Conclusions: The use of warm irrigation fluid better maintains core body temperature and reduces incidence of shivering than room temperature irrigation fluid. Therefore, warm irrigation fluid is a better choice for arthroscopic shoulder surgery. Keywords: irrigation fluid, arthroscopic shoulder surgery, core body temperature, hypothermia, shivering. Ó 2019 by American Society of PeriAnesthesia Nurses
HYPOTHERMIA, DEFINED AS A CORE body temperature #36.0 C, is common in the perioperative period because the central thermoregulation is dysregulated and body heat balance is affected by many factors, such as anesthesia, blood loss, a prolonged operation time, and a cold operating room.1-3 Postoperative hypothermia may result in
hazardous complications such as myocardial ischemia, coagulopathy, surgical wound infection, vomiting, nausea, dizziness, headache, decreased drug metabolism, and shivering.4-9 Owing to these risks, methods of body heat preservation have been instituted for the perioperative period.10-12
Youbin Lin, MD, Chunbin Zhou, MD, Zhaoyong Liu, MD, Kezhou Wu, PhD, Shubiao Chen, MD, Weihao Wang, MD, Yelong Chen, MD, and Hu Wang, MD, Department of Orthopaedics, First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China. Conflict of interest: None to report. Youbin Lin and Chunbin Zhou contributed equally to this study.
Address correspondence to Hu Wang, Department of Orthopaedics, First Affiliated Hospital, Shantou University Medical College, No.57 Changping Road, Shantou, Guangdong 515041, PR China; e-mail address: [email protected]. Ó 2019 by American Society of PeriAnesthesia Nurses 1089-9472/$36.00 https://doi.org/10.1016/j.jopan.2019.06.006
Journal of PeriAnesthesia Nursing, Vol -, No - (-), 2019: pp 1-9
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Despite active and passive warming methods being used in the operating room, hypothermia incidence may be elevated in relation to the duration of anesthesia and the site and extent of surgery.13 Shoulder arthroscopy is a well-established technique in dealing with a variety of shoulder conditions. The most common pathologies treated are instability, rotator cuff tears, subacromial impingement, acromioclavicular joint osteoarthritis, and loose bodies within the joint.14 During the operation, to ensure clear visibility, a large amount of irrigation fluid is required. Considering the shoulder joint is close to the core body structure, the irrigation fluid temperature could adversely affect the core body temperature, resulting in hypothermia-related problems.15-17 The purpose of this study was to compare the use of room temperature and prewarmed irrigation fluid to identify the clinical effects on patients undergoing arthroscopic shoulder surgery. We tested the hypothesis that, compared with room temperature irrigation fluid, the risk of postoperative adverse effects was lower in patients treated with warm irrigation fluid.
Materials and Methods Search Strategy A computerized search of the electronic databases MEDLINE (through PubMed), EMBASE, and the Cochrane Library was performed. There were no restrictions in terms of date, publication, or language of publication. Our searching was performed at March, 2019. The following medical subject heading (MeSH) terms and free words were used in the search strategy: ‘‘therapeutic irrigation’’, ‘‘arthroscopy’’, and ‘‘temperature’’. There were no restrictions in terms of date, publication, or language of publication. The search strategy in Pubmed was as follows: (((((((((((’’Therapeutic Irrigation’’[Mesh]) OR Therapeutic Irrigation[Title/Abstract]) OR Irrigation, Therapeutic[Title/Abstract]) OR Irrigations, Therapeutic[Title/Abstract]) OR Therapeutic Irrigations[Title/Abstract]) OR Lavage[Title/Abstract]) OR Lavages[Title/Abstract]) OR Douching[Title/Abstract])) AND ((((((((((((Surgeries, Arthroscopic[Title/Abstract]) OR Arthroscopic Surgeries[Title/Abstract]) OR Arthroscopic Surgery [Title/Abstract]) OR Surgical Procedures,
Arthroscopic[Title/Abstract]) OR Surgical Procedure, Arthroscopic[Title/Abstract]) OR Procedures, Arthroscopic Surgical[Title/ Abstract]) OR Procedure, Arthroscopic Surgical[Title/Abstract]) OR Arthroscopic Surgical Procedure[Title/Abstract]) OR Arthroscopic Surgical Procedures[Title/ Abstract]) OR Arthroscopies[Title/Abstract]) OR Arthroscopy[Title/Abstract]) OR ‘‘Arthroscopy’’[Mesh]))) AND ((’’Temperature’’ [Mesh]) OR Temperatures[Title/Abstract]) Selection Criteria and Process The present study was in accordance with preferred reporting items for systematic reviews and metaanalyses (PRISMA) guidelines.18,19 Randomized controlled trials or nonrandomized controlled trials in which the use of room temperature irrigation fluid was compared with warm irrigation fluid in arthroscopic shoulder surgery in terms of core body temperature and adverse effects were included. Two authors (Y.L. and C.Z.) independently selected studies with inclusion criteria via screening the titles and abstracts. Then authors reviewed the full texts of the selected studies to determine the inclusion articles. Disagreements were resolved by consulting with a third author. Data Extraction and Management Two authors independently extracted relevant data from eligible studies concerning the room temperature irrigation fluid (RT) group and/or the warm irrigation fluid (W) group and fed them into Microsoft Excel 2007. These included the following categories: study design, conducted country, number of participants, patient characteristics (ie, age, gender, body mass index), anesthesia time, operating time, irrigation fluid volume, intravenous fluid volume, core body temperature, hemoglobin decrease, postoperative weight gain, postoperative pain visual analogue scale (VAS), and adverse effects (hypothermia, shivering, wound infection, vomiting, nausea, dizziness, headache). Assessment of Risk of Bias in Included Studies Two authors independently evaluated the risk of bias of each included study, with the use of Review
IRRIGATION FLUID TEMPERATURE
3
Manager software. Two investigators consulted each other to identify disagreement and to reach consensus by discussion. Any disagreement still existing was verified by W.H.
random-effects model was selected for data analysis.
Test for Heterogeneity
Search Results
The evaluation of statistical heterogeneity was performed with the Higgins I square test. Heterogeneity was considered positive when I2 $ 50%.
Using the search strategy, a total of 41 articles were identified, in which 4 articles met inclusion criteria. A total of 208 patients were included in the systematic review and meta-analysis. The search process is displayed in Figure 1.
Results
Data Analysis For continuous data, pooled results were performed by calculating the mean difference (MD) and its 95% confidence interval (CI) based on the mean value, standard deviation, and the number of participants. For dichotomous data, the risk ratio and its 95% CI was calculated based on the number of events and participants. It was considered statistically significant if the P value was less than 0.05. Assuming heterogeneity existed, a
Study Characteristics The details of the included studies and patient characteristics are summarized in Table 1 and Table 2. The studies included three randomized controlled studies and one nonrandomized controlled study. The study population consisted of 208 patients from three countries. The information about age, gender, and body mass index was mostly provided in studies.
Figure 1. PRISMA flow diagram demonstrating trial inclusion criteria. PRISMA, preferred reporting items for systematic reviews and meta-analyses. This figure appears in color online at www.jopan.org.
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Table 1. Summary of Included Studies Author
Year Country
Board et al15 2008 UK Kim et al20
2009 Korea
Oh et al21
2014 Korea
Pan et al22
2015 China
Study Design
Type of Study
Non-RCT Group RT vs group W RCT Group RT vs group W RCT Group RT vs group W RCT Group RT vs group W
RCT, randomized controlled study; RT, room temperature irrigation fluid; W, warm irrigation fluid.
Risk of Bias in the Included Studies The bias risk assessments were performed and are discussed in the following sections and displayed in Figure 2. Selection Bias A high risk of bias existed at the random sequence generation and allocation concealment during the grouping process in one study.15 Three studies20-22 used randomized controlled methods, and two of them21,22 illustrated the random sequence generation methods. Performance and Detection Bias It was unclear if the participants and personnel were blinded to the performance in all included studies. Furthermore, in almost all studies, it was
unclear if the blinded impartial observer recorded the outcomes. Attrition and Reporting Bias There was a low risk of bias in missing outcome data and selective reporting for studies.
Clinical Results CORE BODY TEMPERATURE. Two studies reported a clear core body temperature drop when using room temperature fluid compared with using warm irrigation fluid.15,20 It was reported clearly that a lower final core body temperature was achieved in the room temperature fluid group than in the warm irrigation fluid group in two studies.20,22 However, another study showed a similar final core body temperature and lowest temperature between the two groups.21 Three studies reported hypothermia perioperatively, involving 184 patients. Two studies clearly reported a lower incidence of hypothermia in the warm irrigation fluid group,20,22 but in another study, a similar incidence of hypothermia was reported between the two groups.21 In general, it was suggested that warm irrigation fluid reduced the degree of core body temperature drop and the incidence of hypothermia. PERIOPERATIVE SHIVERING. Four studies, comprising 208 patients, reported postoperative shivering. The point estimate for the effect size was in favor of the warm irrigation fluid group, and there was statistical significance (risk
Table 2. Patient Characteristics in Included Studies Gender Author Group RT Board et al15 Kim et al20 Oh et al21 Pan et al22 Group W Board et al15 Kim et al20 Oh et al21 Pan et al22
Number of Patients
Mean Age
Male
Female
12 23 36 33
46.42 (20-80) 50.4 (14.5) 58.9 (8.9) 49.2 (11.8)
Not mentioned Not mentioned 14 22 11 22
Not mentioned 24 (3.6) 25.1 (3.7) 24.7 (3.2)
12 23 36 33
45.58 (12-76) 45.8 (13.3) 61.9 (7.8) 47.6 (10.3)
Not mentioned Not mentioned 16 20 17 19
Not mentioned 24.8 (2.7) 26.3 (3.7) 25.7 (3.1)
RT, room temperature irrigation fluid; W, warm irrigation fluid; BMI, body mass index.
BMI
IRRIGATION FLUID TEMPERATURE
5
Figure 2. Illustration summarizing the risk of bias for trails. This figure appears in color online at www.jopan.org.
ratio 5 7.23; 95% CI 5 2.19 to 23.88; P 5 .001; I2 5 0%) (Figure 3), suggesting that a lower incidence of shivering in the warm irrigation fluid group. ANESTHESIA TIME. Data on 184 arthroscopic shoulder surgery patients were pooled from three
trials analyzing the time with general anesthesia.20-22 Although a shorter time duration of anesthesia was shown for room temperature irrigation fluid group in each of the studies, there was no statistical significance (MD 5 24.37; 95% CI 5 212.73 to 3.99; P 5 .31; I2 5 0%) (Table 3).
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Figure 3. Forest plot comparing the risk ratios of the incidence of shivering between room temperature and warm irrigation fluid. CI, confidence interval. This figure appears in color online at www.jopan.org.
OPERATING TIME. Data on 184 arthroscopic shoulder surgery patients were pooled from three trials analyzing the length of the operating time.20-22 There was no statistically significant difference between each group (MD 5 0.09; 95% CI 5 27.25 to 7.42; P 5 .98; I2 5 0%) (Table 3). The operating time in patients receiving room temperature fluid was similar to that in patients receiving warm irrigation fluid. IRRIGATION FLUID VOLUME. Data on 184 arthroscopic shoulder surgery patients were pooled from three trials analyzing the volume of irrigation fluid used in the operation.20-22 Again, there was no statistical significance between groups (MD 5 0.09; 95% CI 5 20.92 to 1.10; P 5 .86; I2 5 0%) (Table 3). INTRAVENOUS FLUID VOLUME. Three studies, involving 184 patients, reported the volume of intravenous fluid used during the operation. It was revealed that the volume of intravenous fluid used in the room temperature irrigation fluid group was less than in the warm irrigation fluid group. For the pooled results, although the point estimate for the effect size was in favor of
the room temperature irrigation fluid group, the difference was not statistically significant (MD 5 234.66; 95% CI 5 288.93 to 19.61; P 5 .21; I2 5 0%) (Table 3). HEMOGLOBIN DECREASE (G/DL). Data on 184 patients undergoing arthroscopic shoulder surgery was pooled from three trials analyzing the blood loss, during the operation, by the decrease in hemoglobin.20-22 There was no statistically significant difference between the two groups (MD 5 20.15; 95% CI 5 20.38 to 0.08; P 5 .20; I2 5 0%) (Table 3). Blood loss in the group receiving room temperature fluid was similar to that in the warm irrigation fluid group. POSTOPERATIVE PAIN VAS. The postoperative pain VAS was reported in three studies involving 184 patients.20-22 Owing to the evaluations of VAS being performed at different time points, we were unable to pool the results for analysis. However, for the reported results, there was no statistically significant difference in VAS between the two groups at each time point. BODY TEMPERATURE RECOVERY. There were only two studies showing the condition of
Table 3. Anesthesia Time, Operating Time, Irrigation Fluid Volume, and Intravenous Fluid Volume for Group RT vs Group W
Anesthesia time Operating time Irrigation fluid volume Intravenous fluid volume Hemoglobin decrease (g/dl)
No. of Studies
WMD
P Value
I2
3 3 3 3 3
24.37 (212.73, 3.99) 0.09 (27.25, 7.42) 0.09 (20.92, 1.10) 234.66 (288.93, 19.61) 20.15 (20.38, 0.08)
0.31 0.98 0.86 0.21 0.20
0% 0% 0% 0% 0%
RT, room temperature irrigation fluid; W, warm irrigation fluid; WMD, weighted mean difference.
IRRIGATION FLUID TEMPERATURE
temperature recovery period in the postanesthesia care unit.21,22 One study indicated that all patients in the two groups returned to normal body temperature within 60 minutes, but that a higher percentage of patients in the warm irrigation fluid group returned to normal within 30 minutes.21 Another study did not describe the details but showed, in a figure, that a faster recovery of body temperature occurred in the warm irrigation fluid group.22 OTHER ADVERSE EFFECTS. In addition to hypothermia and shivering, the incidence of vomiting, nausea, dizziness, and headache was reported in two studies,21,22 and wound infection was reported in another study.15 For all three studies, the incidences between two groups were similar for all adverse effects.
Discussion In this systematic review and meta-analysis, the included studies were composed of three randomized controlled trials and one prospective study. Although we analyzed only four studies, results suggest that irrigation fluid temperature has a significant influence on core body temperature. We found that in situations when there were no statistically significant differences in anesthesia time, operating time, irrigation fluid volume, intravenous fluid volume, and blood loss, warm irrigation fluid reduced the degree of core body temperature drop and the incidence of hypothermia and shivering for patients undergoing arthroscopic shoulder surgery. In addition, the use of warm irrigation fluid was helpful for the restoration of core body temperature to normal after surgery. For the pooled results in the meta-analysis, we found the studies were homogeneous in terms of anesthesia time, operating time, irrigation fluid volume, intravenous fluid volume, and blood loss. As the conditions were similar in terms of anesthetic technique, blanket use, intravenous fluid temperature and volume, irrigation fluid volume, and blood loss, which may affect the results, it would appear that the variation in temperature of the irrigation fluid used in surgery may be the major factor for heterogeneity. The room temperature was set at 22 C, 20 to 22 C, 21 C, and 20 C and the temperature of warm irrigation fluid was set at 36 C, 37 to 39 C, 36 C, and 36 C, respectively, in the four
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studies. As a result, lower incidence of postoperative adverse effects, hypothermia and shivering occurred in the warm irrigation fluid group than in the room temperature irrigation fluid group. Shivering often happened to patients unable to maintain normothermia, and most of them had a core temperature , 36 C. Shivering made patients not only subjectively uncomfortable but was also physiologically stressful and harmful as such events could result in an increase in oxygen demand, catecholamine release, and hypertension.23,24 In our study, the pooled results indicated a statistically lower incidence of shivering occurred in the warm irrigation fluid group. The major factor influencing the incidence of shivering was the temperature of irrigation fluid used during the operation. Results suggested that warm irrigation fluid was beneficial for patients undergoing arthroscopic shoulder surgery. A previous study showed that room temperature irrigation fluid causes a greater drop in core body temperature and higher incidence of shivering and hypothermia than warm irrigation fluid in patients undergoing endoscopic transurethral resection of the prostate.13 Similarly, Dante et al reported that the use of warm irrigation fluid reduced the risk of a decrease in core body temperature during hip arthroscopy.25 In contrast, Kelly et al reported that, during knee arthroscopic surgery, patients receiving warm irrigation fluid were not able to maintain a higher core body temperature than those receiving room temperature irrigation fluids.26 Thus, it was suggested that the affected degree of irrigation fluid temperature on core body temperature was associated with the operative site. The results of our study indicated the core body temperature was susceptible to irrigation fluid temperature during arthroscopic shoulder surgery. The temperature of the warm irrigation fluid was set at 36 C in most of the included studies because it was considered that skin burns or hyperthermia may occur if a temperature greater than 36 C was used. Simon et al reported a case where hot irrigation fluid caused severe damage to joints and soft tissue during knee arthroscopy.27 However, others have reported that using warm irrigation fluid in the range of 37 C to 39 C results in a reduced
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core body temperature drop and lower incidence of hypothermia and shivering,20 and two other studies showed no difference in side effects when using 36 C irrigation fluid, although the core body temperature was affected.21,22 Furthermore, Cheng et al reported that compared with 4 C and 25 C, 37 C irrigation fluid resulted in the least damage to articular cartilage in animal studies, suggesting that 36 C is not the optimum temperature for irrigation fluid applied to arthroscopic shoulder surgery.28 The best temperature of irrigation fluid for arthroscopic shoulder surgery remains to be explored. It was impossible to pool the results of other findings. For VAS, the evaluating time points were different in different studies. For the incidence of vomiting, nausea, dizziness, and headache, there were only two studies reporting these results, and in one study, the number of events was almost zero in both groups. It is clear that there are limitations to our study. The main weakness is that the number of included studies and randomized controlled trials is low. In addition, the heterogeneity is inherent in terms of
core body temperature and incidence of hypothermia. Although a random-effects model was applied to pooled results, substantial differences remained among studies. These differences cause the analyses to be inexact and reduce the credibility of conclusion. Furthermore, the assessment of quality and bias via the Cochrane Group method showed that the included studies have deficiencies in population descriptions, randomization methods, allocation concealment, and blinding. Lastly, although it could be shown that warm irrigation fluid has advantages over room temperature irrigation fluid, the optimum temperature could not be identified for arthroscopic shoulder surgery.
Conclusions Despite the limitations, the results of our systematic review and meta-analysis indicate that, compared with room temperature irrigation fluid, the use of warm irrigation fluid results in better maintenance of core body temperature and reduces the incidence of shivering. Therefore, warm irrigation fluid was a better choice for arthroscopic shoulder surgery.
References 1. The Management of Inadvertent Perioperative Hypothermia in Adults. London: National Collaborating Centre for Nursing and Supportive Care; 2008. 2. Sessler DI. Perioperative heat balance. Anesthesiology. 2000;92:578-596. 3. Buggy DJ, Crossley AW. Thermoregulation, mild perioperative hypothermia and postanaesthetic shivering. Br J Anaesth. 2000;84:615-628. 4. Sessler DI. Complications and treatment of mild hypothermia. Anesthesiology. 2001;95:531-543. 5. Schmied H, Kurz A, Sessler DI, Kozek S, Reiter A. Mild hypothermia increases blood loss and transfusion requirements during total hip arthroplasty. Lancet. 1996;347:289-292. 6. Just B, Delva E, Camus Y, Lienhart A. Oxygen uptake during recovery following naloxone. Relationship with intraoperative heat loss. Anesthesiology. 1992;76:60-64. 7. Frank SM, Fleisher LA, Breslow MJ, et al. Perioperative maintenance of normothermia reduces the incidence of morbid cardiac events. A randomized clinical trial. JAMA. 1997;277: 1127-1134. 8. Kurz A, Sessler DI, Lenhardt R. Perioperative normothermia to reduce the incidence of surgical-wound infection and shorten hospitalization. Study of Wound Infection and Temperature Group. New Engl J Med. 1996;334:1209-1215. 9. Torossian A, Brauer A, Hocker J, Bein B, Wulf H, Horn EP. Preventing inadvertent perioperative hypothermia. Deutsches Arzteblatt Int. 2015;112:166-172.
10. Ng SF, Oo CS, Loh KH, Lim PY, Chan YH, Ong BC. A comparative study of three warming interventions to determine the most effective in maintaining perioperative normothermia. Anesth Analgesia. 2003;96:171-176. table of contents. 11. Ouellette RG. Comparison of four intraoperative warming devices. AANA J. 1993;61:394-396. 12. Kurz A. Thermal care in the perioperative period. Best Pract Res Clin Anaesthesiology. 2008;22:39-62. 13. Jin Y, Tian J, Sun M, Yang K. A systematic review of randomised controlled trials of the effects of warmed irrigation fluid on core body temperature during endoscopic surgeries. J Clin Nurs. 2011;20:305-316. 14. Baraza N, Leith J. Are prophylactic intravenous antibiotics required in routine shoulder arthroscopic surgery? A systematic review of the literature. Joints. 2018;6:54-57. 15. Board TN, Srinivasan MS. The effect of irrigation fluid temperature on core body temperature in arthroscopic shoulder surgery. Arch Orthopaedic Trauma Surg. 2008;128: 531-533. 16. Smith CD, Shah MM. Fluid gain during routine shoulder arthroscopy. J Shoulder Elbow Surg. 2008;17:415-417. 17. Duff J, Di Staso R, Cobbe KA, et al. Preventing hypothermia in elective arthroscopic shoulder surgery patients: a protocol for a randomised controlled trial. BMC Surg. 2012;12:14. 18. Liberati A, Altman DG, Tetzlaff J, et al. The PRISMA statement for reporting systematic reviews and meta-analyses of
IRRIGATION FLUID TEMPERATURE studies that evaluate healthcare interventions: explanation and elaboration. BMJ. 2009;339:b2700. 19. Juni P, Egger M. PRISMAtic reporting of systematic reviews and meta-analyses. Lancet. 2009;374:1221-1223. 20. Kim YS, Lee JY, Yang SC, Song JH, Koh HS, Park WK. Comparative study of the influence of room-temperature and warmed fluid irrigation on body temperature in arthroscopic shoulder surgery. Arthroscopy. 2009;25:24-29. 21. Oh JH, Kim JY, Chung SW, et al. Warmed irrigation fluid does not decrease perioperative hypothermia during arthroscopic shoulder surgery. Arthroscopy. 2014;30: 159-164. 22. Pan X, Ye L, Liu Z, Wen H, Hu Y, Xu X. Effect of irrigation fluid temperature on core body temperature and inflammatory response during arthroscopic shoulder surgery. Arch Orthopaedic Trauma Surg. 2015;135:1131-1139. 23. Rhodes JKJ, Sinclair HL, Battison CG, Harris B, Andrews PJD. Shivering management during therapeutic hypothermia in patients with traumatic brain injury: Protocol
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from the Eurotherm 3235 trial. BMC Emerg Med. 2015;15: A7. 24. Zhou P, Ge S, Wang Y, Xiong W, Wang T, Xue Z. Novamin infusion: a new method to cure postoperative shivering with hypothermia. J Surg Res. 2014;188:69-76. 25. Parodi D, Valderrama J, Tobar C, et al. Effect of warmed irrigation solution on core body temperature during hip arthroscopy for femoroacetabular impingement. Arthroscopy. 2014; 30:36-41. 26. Kelly JA, Doughty JK, Hasselbeck AN, Vacchiano CA. The effect of arthroscopic irrigation fluid warming on body temperature. J Perianesthesia Nurs. 2000;15:245-252. 27. Huang S, Gateley D, Moss AL. Accidental burn injury during knee arthroscopy. Arthroscopy. 2007;23: 1363.e1-1363.e3. 28. Cheng SC, Jou IM, Chern TC, Wang PH, Chen WC. The effect of normal saline irrigation at different temperatures on the surface of articular cartilage: an experimental study in the rat. Arthroscopy. 2004;20:55-61.
Room Temperature Versus Warm Irrigation Fluid Used for Patients Undergoing Arthroscopic Shoulder Surgery: A Systematic Review and Meta Analysis Youbin Lin, MD, Chunbin Zhou, MD, Zhaoyong Liu, MD, Kezhou Wu, PhD, Shubiao Chen, MD, Weihao Wang, MD, Yelong Chen, MD, Hu Wang, MD Purpose: The aim of this study was to analyze whether warm irrigation fluid could reduce postoperative adverse effects in patients undergoing arthroscopic shoulder surgery compared with room temperature irrigation fluid. Design: A systematic review and meta-analysis of clinical trials was performed. Methods: A computerized search of electronic databases was performed. The inclusion criteria were studies comparing the clinical effects of room temperature and warm irrigation fluid on patients undergoing arthroscopic shoulder surgery. Findings: Warm irrigation fluid reduced the degree of core body temperature drop and the incidence of hypothermia. A statistically lower incidence of shivering also occurred in the warm irrigation fluid group. Conclusions: The use of warm irrigation fluid better maintains core body temperature and reduces incidence of shivering than room temperature irrigation fluid. Therefore, warm irrigation fluid is a better choice for arthroscopic shoulder surgery. Keywords: irrigation fluid, arthroscopic shoulder surgery, core body temperature, hypothermia, shivering. Ó 2019 by American Society of PeriAnesthesia Nurses
HYPOTHERMIA, DEFINED AS A CORE body temperature #36.0 C, is common in the perioperative period because the central thermoregulation is dysregulated and body heat balance is affected by many factors, such as anesthesia, blood loss, a prolonged operation time, and a cold operating room.1-3 Postoperative hypothermia may result in
hazardous complications such as myocardial ischemia, coagulopathy, surgical wound infection, vomiting, nausea, dizziness, headache, decreased drug metabolism, and shivering.4-9 Owing to these risks, methods of body heat preservation have been instituted for the perioperative period.10-12
Youbin Lin, MD, Chunbin Zhou, MD, Zhaoyong Liu, MD, Kezhou Wu, PhD, Shubiao Chen, MD, Weihao Wang, MD, Yelong Chen, MD, and Hu Wang, MD, Department of Orthopaedics, First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China. Conflict of interest: None to report. Youbin Lin and Chunbin Zhou contributed equally to this study.
Address correspondence to Hu Wang, Department of Orthopaedics, First Affiliated Hospital, Shantou University Medical College, No.57 Changping Road, Shantou, Guangdong 515041, PR China; e-mail address: [email protected]. Ó 2019 by American Society of PeriAnesthesia Nurses 1089-9472/$36.00 https://doi.org/10.1016/j.jopan.2019.06.006
Journal of PeriAnesthesia Nursing, Vol -, No - (-), 2019: pp 1-9
1
LIN ET AL
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Despite active and passive warming methods being used in the operating room, hypothermia incidence may be elevated in relation to the duration of anesthesia and the site and extent of surgery.13 Shoulder arthroscopy is a well-established technique in dealing with a variety of shoulder conditions. The most common pathologies treated are instability, rotator cuff tears, subacromial impingement, acromioclavicular joint osteoarthritis, and loose bodies within the joint.14 During the operation, to ensure clear visibility, a large amount of irrigation fluid is required. Considering the shoulder joint is close to the core body structure, the irrigation fluid temperature could adversely affect the core body temperature, resulting in hypothermia-related problems.15-17 The purpose of this study was to compare the use of room temperature and prewarmed irrigation fluid to identify the clinical effects on patients undergoing arthroscopic shoulder surgery. We tested the hypothesis that, compared with room temperature irrigation fluid, the risk of postoperative adverse effects was lower in patients treated with warm irrigation fluid.
Materials and Methods Search Strategy A computerized search of the electronic databases MEDLINE (through PubMed), EMBASE, and the Cochrane Library was performed. There were no restrictions in terms of date, publication, or language of publication. Our searching was performed at March, 2019. The following medical subject heading (MeSH) terms and free words were used in the search strategy: ‘‘therapeutic irrigation’’, ‘‘arthroscopy’’, and ‘‘temperature’’. There were no restrictions in terms of date, publication, or language of publication. The search strategy in Pubmed was as follows: (((((((((((’’Therapeutic Irrigation’’[Mesh]) OR Therapeutic Irrigation[Title/Abstract]) OR Irrigation, Therapeutic[Title/Abstract]) OR Irrigations, Therapeutic[Title/Abstract]) OR Therapeutic Irrigations[Title/Abstract]) OR Lavage[Title/Abstract]) OR Lavages[Title/Abstract]) OR Douching[Title/Abstract])) AND ((((((((((((Surgeries, Arthroscopic[Title/Abstract]) OR Arthroscopic Surgeries[Title/Abstract]) OR Arthroscopic Surgery [Title/Abstract]) OR Surgical Procedures,
Arthroscopic[Title/Abstract]) OR Surgical Procedure, Arthroscopic[Title/Abstract]) OR Procedures, Arthroscopic Surgical[Title/ Abstract]) OR Procedure, Arthroscopic Surgical[Title/Abstract]) OR Arthroscopic Surgical Procedure[Title/Abstract]) OR Arthroscopic Surgical Procedures[Title/ Abstract]) OR Arthroscopies[Title/Abstract]) OR Arthroscopy[Title/Abstract]) OR ‘‘Arthroscopy’’[Mesh]))) AND ((’’Temperature’’ [Mesh]) OR Temperatures[Title/Abstract]) Selection Criteria and Process The present study was in accordance with preferred reporting items for systematic reviews and metaanalyses (PRISMA) guidelines.18,19 Randomized controlled trials or nonrandomized controlled trials in which the use of room temperature irrigation fluid was compared with warm irrigation fluid in arthroscopic shoulder surgery in terms of core body temperature and adverse effects were included. Two authors (Y.L. and C.Z.) independently selected studies with inclusion criteria via screening the titles and abstracts. Then authors reviewed the full texts of the selected studies to determine the inclusion articles. Disagreements were resolved by consulting with a third author. Data Extraction and Management Two authors independently extracted relevant data from eligible studies concerning the room temperature irrigation fluid (RT) group and/or the warm irrigation fluid (W) group and fed them into Microsoft Excel 2007. These included the following categories: study design, conducted country, number of participants, patient characteristics (ie, age, gender, body mass index), anesthesia time, operating time, irrigation fluid volume, intravenous fluid volume, core body temperature, hemoglobin decrease, postoperative weight gain, postoperative pain visual analogue scale (VAS), and adverse effects (hypothermia, shivering, wound infection, vomiting, nausea, dizziness, headache). Assessment of Risk of Bias in Included Studies Two authors independently evaluated the risk of bias of each included study, with the use of Review
IRRIGATION FLUID TEMPERATURE
3
Manager software. Two investigators consulted each other to identify disagreement and to reach consensus by discussion. Any disagreement still existing was verified by W.H.
random-effects model was selected for data analysis.
Test for Heterogeneity
Search Results
The evaluation of statistical heterogeneity was performed with the Higgins I square test. Heterogeneity was considered positive when I2 $ 50%.
Using the search strategy, a total of 41 articles were identified, in which 4 articles met inclusion criteria. A total of 208 patients were included in the systematic review and meta-analysis. The search process is displayed in Figure 1.
Results
Data Analysis For continuous data, pooled results were performed by calculating the mean difference (MD) and its 95% confidence interval (CI) based on the mean value, standard deviation, and the number of participants. For dichotomous data, the risk ratio and its 95% CI was calculated based on the number of events and participants. It was considered statistically significant if the P value was less than 0.05. Assuming heterogeneity existed, a
Study Characteristics The details of the included studies and patient characteristics are summarized in Table 1 and Table 2. The studies included three randomized controlled studies and one nonrandomized controlled study. The study population consisted of 208 patients from three countries. The information about age, gender, and body mass index was mostly provided in studies.
Figure 1. PRISMA flow diagram demonstrating trial inclusion criteria. PRISMA, preferred reporting items for systematic reviews and meta-analyses. This figure appears in color online at www.jopan.org.
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Table 1. Summary of Included Studies Author
Year Country
Board et al15 2008 UK Kim et al20
2009 Korea
Oh et al21
2014 Korea
Pan et al22
2015 China
Study Design
Type of Study
Non-RCT Group RT vs group W RCT Group RT vs group W RCT Group RT vs group W RCT Group RT vs group W
RCT, randomized controlled study; RT, room temperature irrigation fluid; W, warm irrigation fluid.
Risk of Bias in the Included Studies The bias risk assessments were performed and are discussed in the following sections and displayed in Figure 2. Selection Bias A high risk of bias existed at the random sequence generation and allocation concealment during the grouping process in one study.15 Three studies20-22 used randomized controlled methods, and two of them21,22 illustrated the random sequence generation methods. Performance and Detection Bias It was unclear if the participants and personnel were blinded to the performance in all included studies. Furthermore, in almost all studies, it was
unclear if the blinded impartial observer recorded the outcomes. Attrition and Reporting Bias There was a low risk of bias in missing outcome data and selective reporting for studies.
Clinical Results CORE BODY TEMPERATURE. Two studies reported a clear core body temperature drop when using room temperature fluid compared with using warm irrigation fluid.15,20 It was reported clearly that a lower final core body temperature was achieved in the room temperature fluid group than in the warm irrigation fluid group in two studies.20,22 However, another study showed a similar final core body temperature and lowest temperature between the two groups.21 Three studies reported hypothermia perioperatively, involving 184 patients. Two studies clearly reported a lower incidence of hypothermia in the warm irrigation fluid group,20,22 but in another study, a similar incidence of hypothermia was reported between the two groups.21 In general, it was suggested that warm irrigation fluid reduced the degree of core body temperature drop and the incidence of hypothermia. PERIOPERATIVE SHIVERING. Four studies, comprising 208 patients, reported postoperative shivering. The point estimate for the effect size was in favor of the warm irrigation fluid group, and there was statistical significance (risk
Table 2. Patient Characteristics in Included Studies Gender Author Group RT Board et al15 Kim et al20 Oh et al21 Pan et al22 Group W Board et al15 Kim et al20 Oh et al21 Pan et al22
Number of Patients
Mean Age
Male
Female
12 23 36 33
46.42 (20-80) 50.4 (14.5) 58.9 (8.9) 49.2 (11.8)
Not mentioned Not mentioned 14 22 11 22
Not mentioned 24 (3.6) 25.1 (3.7) 24.7 (3.2)
12 23 36 33
45.58 (12-76) 45.8 (13.3) 61.9 (7.8) 47.6 (10.3)
Not mentioned Not mentioned 16 20 17 19
Not mentioned 24.8 (2.7) 26.3 (3.7) 25.7 (3.1)
RT, room temperature irrigation fluid; W, warm irrigation fluid; BMI, body mass index.
BMI
IRRIGATION FLUID TEMPERATURE
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Figure 2. Illustration summarizing the risk of bias for trails. This figure appears in color online at www.jopan.org.
ratio 5 7.23; 95% CI 5 2.19 to 23.88; P 5 .001; I2 5 0%) (Figure 3), suggesting that a lower incidence of shivering in the warm irrigation fluid group. ANESTHESIA TIME. Data on 184 arthroscopic shoulder surgery patients were pooled from three
trials analyzing the time with general anesthesia.20-22 Although a shorter time duration of anesthesia was shown for room temperature irrigation fluid group in each of the studies, there was no statistical significance (MD 5 24.37; 95% CI 5 212.73 to 3.99; P 5 .31; I2 5 0%) (Table 3).
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Figure 3. Forest plot comparing the risk ratios of the incidence of shivering between room temperature and warm irrigation fluid. CI, confidence interval. This figure appears in color online at www.jopan.org.
OPERATING TIME. Data on 184 arthroscopic shoulder surgery patients were pooled from three trials analyzing the length of the operating time.20-22 There was no statistically significant difference between each group (MD 5 0.09; 95% CI 5 27.25 to 7.42; P 5 .98; I2 5 0%) (Table 3). The operating time in patients receiving room temperature fluid was similar to that in patients receiving warm irrigation fluid. IRRIGATION FLUID VOLUME. Data on 184 arthroscopic shoulder surgery patients were pooled from three trials analyzing the volume of irrigation fluid used in the operation.20-22 Again, there was no statistical significance between groups (MD 5 0.09; 95% CI 5 20.92 to 1.10; P 5 .86; I2 5 0%) (Table 3). INTRAVENOUS FLUID VOLUME. Three studies, involving 184 patients, reported the volume of intravenous fluid used during the operation. It was revealed that the volume of intravenous fluid used in the room temperature irrigation fluid group was less than in the warm irrigation fluid group. For the pooled results, although the point estimate for the effect size was in favor of
the room temperature irrigation fluid group, the difference was not statistically significant (MD 5 234.66; 95% CI 5 288.93 to 19.61; P 5 .21; I2 5 0%) (Table 3). HEMOGLOBIN DECREASE (G/DL). Data on 184 patients undergoing arthroscopic shoulder surgery was pooled from three trials analyzing the blood loss, during the operation, by the decrease in hemoglobin.20-22 There was no statistically significant difference between the two groups (MD 5 20.15; 95% CI 5 20.38 to 0.08; P 5 .20; I2 5 0%) (Table 3). Blood loss in the group receiving room temperature fluid was similar to that in the warm irrigation fluid group. POSTOPERATIVE PAIN VAS. The postoperative pain VAS was reported in three studies involving 184 patients.20-22 Owing to the evaluations of VAS being performed at different time points, we were unable to pool the results for analysis. However, for the reported results, there was no statistically significant difference in VAS between the two groups at each time point. BODY TEMPERATURE RECOVERY. There were only two studies showing the condition of
Table 3. Anesthesia Time, Operating Time, Irrigation Fluid Volume, and Intravenous Fluid Volume for Group RT vs Group W
Anesthesia time Operating time Irrigation fluid volume Intravenous fluid volume Hemoglobin decrease (g/dl)
No. of Studies
WMD
P Value
I2
3 3 3 3 3
24.37 (212.73, 3.99) 0.09 (27.25, 7.42) 0.09 (20.92, 1.10) 234.66 (288.93, 19.61) 20.15 (20.38, 0.08)
0.31 0.98 0.86 0.21 0.20
0% 0% 0% 0% 0%
RT, room temperature irrigation fluid; W, warm irrigation fluid; WMD, weighted mean difference.
IRRIGATION FLUID TEMPERATURE
temperature recovery period in the postanesthesia care unit.21,22 One study indicated that all patients in the two groups returned to normal body temperature within 60 minutes, but that a higher percentage of patients in the warm irrigation fluid group returned to normal within 30 minutes.21 Another study did not describe the details but showed, in a figure, that a faster recovery of body temperature occurred in the warm irrigation fluid group.22 OTHER ADVERSE EFFECTS. In addition to hypothermia and shivering, the incidence of vomiting, nausea, dizziness, and headache was reported in two studies,21,22 and wound infection was reported in another study.15 For all three studies, the incidences between two groups were similar for all adverse effects.
Discussion In this systematic review and meta-analysis, the included studies were composed of three randomized controlled trials and one prospective study. Although we analyzed only four studies, results suggest that irrigation fluid temperature has a significant influence on core body temperature. We found that in situations when there were no statistically significant differences in anesthesia time, operating time, irrigation fluid volume, intravenous fluid volume, and blood loss, warm irrigation fluid reduced the degree of core body temperature drop and the incidence of hypothermia and shivering for patients undergoing arthroscopic shoulder surgery. In addition, the use of warm irrigation fluid was helpful for the restoration of core body temperature to normal after surgery. For the pooled results in the meta-analysis, we found the studies were homogeneous in terms of anesthesia time, operating time, irrigation fluid volume, intravenous fluid volume, and blood loss. As the conditions were similar in terms of anesthetic technique, blanket use, intravenous fluid temperature and volume, irrigation fluid volume, and blood loss, which may affect the results, it would appear that the variation in temperature of the irrigation fluid used in surgery may be the major factor for heterogeneity. The room temperature was set at 22 C, 20 to 22 C, 21 C, and 20 C and the temperature of warm irrigation fluid was set at 36 C, 37 to 39 C, 36 C, and 36 C, respectively, in the four
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studies. As a result, lower incidence of postoperative adverse effects, hypothermia and shivering occurred in the warm irrigation fluid group than in the room temperature irrigation fluid group. Shivering often happened to patients unable to maintain normothermia, and most of them had a core temperature , 36 C. Shivering made patients not only subjectively uncomfortable but was also physiologically stressful and harmful as such events could result in an increase in oxygen demand, catecholamine release, and hypertension.23,24 In our study, the pooled results indicated a statistically lower incidence of shivering occurred in the warm irrigation fluid group. The major factor influencing the incidence of shivering was the temperature of irrigation fluid used during the operation. Results suggested that warm irrigation fluid was beneficial for patients undergoing arthroscopic shoulder surgery. A previous study showed that room temperature irrigation fluid causes a greater drop in core body temperature and higher incidence of shivering and hypothermia than warm irrigation fluid in patients undergoing endoscopic transurethral resection of the prostate.13 Similarly, Dante et al reported that the use of warm irrigation fluid reduced the risk of a decrease in core body temperature during hip arthroscopy.25 In contrast, Kelly et al reported that, during knee arthroscopic surgery, patients receiving warm irrigation fluid were not able to maintain a higher core body temperature than those receiving room temperature irrigation fluids.26 Thus, it was suggested that the affected degree of irrigation fluid temperature on core body temperature was associated with the operative site. The results of our study indicated the core body temperature was susceptible to irrigation fluid temperature during arthroscopic shoulder surgery. The temperature of the warm irrigation fluid was set at 36 C in most of the included studies because it was considered that skin burns or hyperthermia may occur if a temperature greater than 36 C was used. Simon et al reported a case where hot irrigation fluid caused severe damage to joints and soft tissue during knee arthroscopy.27 However, others have reported that using warm irrigation fluid in the range of 37 C to 39 C results in a reduced
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core body temperature drop and lower incidence of hypothermia and shivering,20 and two other studies showed no difference in side effects when using 36 C irrigation fluid, although the core body temperature was affected.21,22 Furthermore, Cheng et al reported that compared with 4 C and 25 C, 37 C irrigation fluid resulted in the least damage to articular cartilage in animal studies, suggesting that 36 C is not the optimum temperature for irrigation fluid applied to arthroscopic shoulder surgery.28 The best temperature of irrigation fluid for arthroscopic shoulder surgery remains to be explored. It was impossible to pool the results of other findings. For VAS, the evaluating time points were different in different studies. For the incidence of vomiting, nausea, dizziness, and headache, there were only two studies reporting these results, and in one study, the number of events was almost zero in both groups. It is clear that there are limitations to our study. The main weakness is that the number of included studies and randomized controlled trials is low. In addition, the heterogeneity is inherent in terms of
core body temperature and incidence of hypothermia. Although a random-effects model was applied to pooled results, substantial differences remained among studies. These differences cause the analyses to be inexact and reduce the credibility of conclusion. Furthermore, the assessment of quality and bias via the Cochrane Group method showed that the included studies have deficiencies in population descriptions, randomization methods, allocation concealment, and blinding. Lastly, although it could be shown that warm irrigation fluid has advantages over room temperature irrigation fluid, the optimum temperature could not be identified for arthroscopic shoulder surgery.
Conclusions Despite the limitations, the results of our systematic review and meta-analysis indicate that, compared with room temperature irrigation fluid, the use of warm irrigation fluid results in better maintenance of core body temperature and reduces the incidence of shivering. Therefore, warm irrigation fluid was a better choice for arthroscopic shoulder surgery.
References 1. The Management of Inadvertent Perioperative Hypothermia in Adults. London: National Collaborating Centre for Nursing and Supportive Care; 2008. 2. Sessler DI. Perioperative heat balance. Anesthesiology. 2000;92:578-596. 3. Buggy DJ, Crossley AW. Thermoregulation, mild perioperative hypothermia and postanaesthetic shivering. Br J Anaesth. 2000;84:615-628. 4. Sessler DI. Complications and treatment of mild hypothermia. Anesthesiology. 2001;95:531-543. 5. Schmied H, Kurz A, Sessler DI, Kozek S, Reiter A. Mild hypothermia increases blood loss and transfusion requirements during total hip arthroplasty. Lancet. 1996;347:289-292. 6. Just B, Delva E, Camus Y, Lienhart A. Oxygen uptake during recovery following naloxone. Relationship with intraoperative heat loss. Anesthesiology. 1992;76:60-64. 7. Frank SM, Fleisher LA, Breslow MJ, et al. Perioperative maintenance of normothermia reduces the incidence of morbid cardiac events. A randomized clinical trial. JAMA. 1997;277: 1127-1134. 8. Kurz A, Sessler DI, Lenhardt R. Perioperative normothermia to reduce the incidence of surgical-wound infection and shorten hospitalization. Study of Wound Infection and Temperature Group. New Engl J Med. 1996;334:1209-1215. 9. Torossian A, Brauer A, Hocker J, Bein B, Wulf H, Horn EP. Preventing inadvertent perioperative hypothermia. Deutsches Arzteblatt Int. 2015;112:166-172.
10. Ng SF, Oo CS, Loh KH, Lim PY, Chan YH, Ong BC. A comparative study of three warming interventions to determine the most effective in maintaining perioperative normothermia. Anesth Analgesia. 2003;96:171-176. table of contents. 11. Ouellette RG. Comparison of four intraoperative warming devices. AANA J. 1993;61:394-396. 12. Kurz A. Thermal care in the perioperative period. Best Pract Res Clin Anaesthesiology. 2008;22:39-62. 13. Jin Y, Tian J, Sun M, Yang K. A systematic review of randomised controlled trials of the effects of warmed irrigation fluid on core body temperature during endoscopic surgeries. J Clin Nurs. 2011;20:305-316. 14. Baraza N, Leith J. Are prophylactic intravenous antibiotics required in routine shoulder arthroscopic surgery? A systematic review of the literature. Joints. 2018;6:54-57. 15. Board TN, Srinivasan MS. The effect of irrigation fluid temperature on core body temperature in arthroscopic shoulder surgery. Arch Orthopaedic Trauma Surg. 2008;128: 531-533. 16. Smith CD, Shah MM. Fluid gain during routine shoulder arthroscopy. J Shoulder Elbow Surg. 2008;17:415-417. 17. Duff J, Di Staso R, Cobbe KA, et al. Preventing hypothermia in elective arthroscopic shoulder surgery patients: a protocol for a randomised controlled trial. BMC Surg. 2012;12:14. 18. Liberati A, Altman DG, Tetzlaff J, et al. The PRISMA statement for reporting systematic reviews and meta-analyses of
IRRIGATION FLUID TEMPERATURE studies that evaluate healthcare interventions: explanation and elaboration. BMJ. 2009;339:b2700. 19. Juni P, Egger M. PRISMAtic reporting of systematic reviews and meta-analyses. Lancet. 2009;374:1221-1223. 20. Kim YS, Lee JY, Yang SC, Song JH, Koh HS, Park WK. Comparative study of the influence of room-temperature and warmed fluid irrigation on body temperature in arthroscopic shoulder surgery. Arthroscopy. 2009;25:24-29. 21. Oh JH, Kim JY, Chung SW, et al. Warmed irrigation fluid does not decrease perioperative hypothermia during arthroscopic shoulder surgery. Arthroscopy. 2014;30: 159-164. 22. Pan X, Ye L, Liu Z, Wen H, Hu Y, Xu X. Effect of irrigation fluid temperature on core body temperature and inflammatory response during arthroscopic shoulder surgery. Arch Orthopaedic Trauma Surg. 2015;135:1131-1139. 23. Rhodes JKJ, Sinclair HL, Battison CG, Harris B, Andrews PJD. Shivering management during therapeutic hypothermia in patients with traumatic brain injury: Protocol
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from the Eurotherm 3235 trial. BMC Emerg Med. 2015;15: A7. 24. Zhou P, Ge S, Wang Y, Xiong W, Wang T, Xue Z. Novamin infusion: a new method to cure postoperative shivering with hypothermia. J Surg Res. 2014;188:69-76. 25. Parodi D, Valderrama J, Tobar C, et al. Effect of warmed irrigation solution on core body temperature during hip arthroscopy for femoroacetabular impingement. Arthroscopy. 2014; 30:36-41. 26. Kelly JA, Doughty JK, Hasselbeck AN, Vacchiano CA. The effect of arthroscopic irrigation fluid warming on body temperature. J Perianesthesia Nurs. 2000;15:245-252. 27. Huang S, Gateley D, Moss AL. Accidental burn injury during knee arthroscopy. Arthroscopy. 2007;23: 1363.e1-1363.e3. 28. Cheng SC, Jou IM, Chern TC, Wang PH, Chen WC. The effect of normal saline irrigation at different temperatures on the surface of articular cartilage: an experimental study in the rat. Arthroscopy. 2004;20:55-61.