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Anesth Pain Med > Volume 11(2); 2016 > Article
Seo, Kim, Oh, Moon, Kim, and Hwang: Effect of electrically heated humidifier on intraoperative core body temperature decrease in elderly patients: a prospective observational study



Core body temperature (TC) can decrease during general anesthesia. Particularly in elderly patients, more aggressive strategies to prevent intraoperative hypothermia may be required. Here, we investigated the effect of a heated humidifier on intraoperative TC decrease in the elderly.


Twenty-four elderly patients were randomly assigned into two groups: those who used a heated humidifier (group H) and those who used a conventional ventilator circuit with a heat moisture exchanger (group C). TC was measured continuously at the esophagus at several time-points during surgery.


In group C, TC significantly decreased 90 minutes after skin incision (P < 0.001), while significant differences were not noted in group H during surgery. Comparing the two groups, TC decreased more in group C than in group H at 60, 90, 120, and 150 minutes after skin incision (group C vs. group H: −0.6°C vs. −0.3°C, P = 0.025; −0.7°C vs. −0.4°C, P = 0.012; −0.9°C vs. −0.4°C, P = 0.006; and −1.0°C vs. −0.5°C, P = 0.013, respectively). There were no significant differences between the two groups for any other parameters.


A heated humidifier is more effective in preventing intraoperative TC decrease in elderly patients than a heat moisture exchanger. However, further studies with a larger population are required to substantiate its clinical use.


Core body temperature (TC) can decrease during general anesthesia and surgery [1]. Various factors including low ambient temperature [2], cold intravenous fluids, open abdominal surgery [3], drug induced vasodilation [2], and the inspiration of cold fresh gas can decrease TC [4], which can contribute to perioperative complications such as delayed awakening and coagulopathy [5,6]. Particularly in elderly patients, heat production can decrease and vasoconstrictor response to a cold stress can be attenuated during surgery [7,8]. This can lead to decreased TC; therefore, careful consideration is required to maintain temperature homeostasis during general anesthesia in elderly patients [9].
Many active warming devices, such as a forced-air warming system and water-circulating mattress, are used to prevent intraoperative TC decrease [10,11]. Electrically heated humidifiers (HH) can deliver warmed gas directly to the lower respiratory tract. Compared to a heat and moisture exchanger (HME), which is widely used during mechanical ventilation, HH may provide additional heat energy, thereby being more effective for maintaining TC [12-15]. However, previous studies comparing HH to a conventional circuit without HME [12] were limited by use of aural canal temperature, which is not representative of TC, [13] or by being performed in specialized surgical conditions such as liver transplantation [15]. Therefore, the effect of HH, compared to HME, on intraoperative TC decrease has not been well defined, particularly in elderly patients under general anesthesia.
Because HH can provide direct heat energy, we thought that using HH would be more effective in preventing TC decrease than using HME. To evaluate the effect of both devices on intraoperative TC change, we serially measured TC at specific time-points and investigated the change in TC from baseline. 


After obtaining approval from our Institutional Review Board and registering with Clinical Research Information Service (registration number: KCT0000910), this study was conducted between March 2013 and December 2013. A total of 24 elderly patients undergoing open urologic surgery were enrolled after obtaining written informed consent. All patients were ASA physical status 1 or 2, and patients with any history of severe cardiopulmonary disease, abnormal pulmonary function on preoperative testing, obese patients (body mass index, BMI > 30 kg/m2), thin patients (BMI < 18.5 kg/m2), and those with abnormal preoperative temperature (> 38°C or < 36°C) were excluded. All patients were evaluated with standard preoperative work-up examinations at our institution. None of the patients were premedicated.
After admission for surgery, all patients were randomly assigned into one of two groups by using computer-generated random numbers. Mechanical ventilation was achieved using a conventional ventilator circuit with HME in group C (n = 12) or using a HH in group H (n = 12). In group C, HME (Humid Vent, Gibeck, Sweden), was placed between the tracheal tube and a Y-piece of the ventilatory circuit. In group H, HH (ANAPOD™, Westmed Inc. Tucson, AZ, USA) was used to deliver warmed and humidified inspiratory gas. HH consisted of an electrically heated wire that was set to 38°C by a servo-control system and water-absorbing sponge in the inspiratory limb.
In accordance with our institutional standards, the same intraoperative patient monitoring protocol was applied in both groups. General anesthesia was induced with thiopental sodium 5 mg/kg, and vecuronium 0.15 mg/kg was used to facilitate tracheal intubation. Anesthesia was maintained by administering 1-3 vol% sevoflurane and 2 L/min of 50% oxygen and medical air mixture. The depth of anesthesia was monitored using the bispectral index (BIS A-1050 Monitor, Aspect Medical Systems, Newton, MA) and was maintained between 40-60 during surgery. Patients were connected to the anesthesia machine (Primus®; Drägerwerk AG & Co., Lübeck, Germany) and ventilated using a tidal volume of 6-8 ml/kg of the patient’s ideal body weight and 8 cmH2O of positive end-expiratory pressure. The respiratory rate was adjusted to maintain normocapnia. Administered intravenous fluid was warmed to 37°C by a fluid warming device, and packed red blood cells were administered at ambient temperature. During surgery, mean blood pressure was maintained > 65 mmHg and heart rate at < 110 beats/min. Transfusion was initiated when the intraoperative hemoglobin level was < 8 g/dl. Patients were aggressively warmed by forced-air warming system (Bair Hugger™, 3M, St. Paul, MN, USA) when TC decreased < 35.5°C or after 150 minutes of skin incision.

Outcome measurement

Temperatures were measured at three different sites (esophagus, aural canal, and right forearm) during surgery. Esophagus temperature, considered as the TC, was continuously measured using an esophageal stethoscope with temperature sensor (Esophageal Stethoscope; DeRoyal Inc., Powell, TN, USA). An esophageal stethoscope was placed at the site where the heartbeat was best heard. Skin temperature (TS) was measured using an attachable probe (Skin temperature probe; Datex-Ohmeda, Helsinki, Finland) that was placed at the center of the anterior aspect of the right forearm. The right forearm of each patient was exposed to ambient environment during the intraoperative period.
To measure the primary outcomes, an esophageal probe was inserted immediately after tracheal intubation to the depth of the maximal cardiac sounds on auscultation. TC was recorded immediately after intubation as the baseline reading. After baseline values were measured, TC was repeatedly recorded at 15, 30, 45, 60, 90, 120, and 150 minutes after skin incision, and at the end of surgery. At each time-point, TS was monitored to assess the peripheral vasodilation occurring at the initial phase of TC decrease. Each TS measurement was performed simultaneously with the corresponding TC measurement.
For other outcomes, we assessed the amount of administered fluid and transfusion incidence. Additionally, we evaluated temperature, the amount of administered opioid, and the incidence of shivering at the postanesthesia care unit.

Statistical analysis

In a previous pilot study, the mean TC decrease from baseline 150 minutes after skin incision was 1.3°C ± 0.5°C in patients using HME and 0.7°C ± 0.5°C in patients using HH. Assuming a type I error of 0.05 and a desired power of 0.80 to test the alternative hypothesis that TC decrease was different between group H and group C, 12 patients were required for the present analysis. All data were expressed as numbers (%), the median [interquartile range], or the mean ± standard deviation (SD). Statistical analyses were performed using IBM SPSS 21.0 (IBM Corp., Armonk, NY, USA). The Shapiro-Wilk test was used to test the normality of the data. Repeated measure analysis of variance was performed to evaluate TC changes in each group. The Mann-Whitney rank-sum test was used to compare temperature between the two groups at each time-point. The student’s t-test was used to compare linear data, and Fisher’s exact test or the chi-square test was used to compare categorical data between groups. A P < 0.05 is considered to be statistically significant.


A total of 24 patients were enrolled, and none dropped out during the course of the study. Demographic data of patients are presented in Table 1. No significant differences were seen in demographics between group C and group H. Intraoperative and postoperative data are listed in Table 2. There were no significant differences in intraoperative data and postoperative outcomes between the two groups.
Table 1
Patient Demographics and Type of Surgery
Variables Group C (n = 12) Group H (n = 12) P value
Age (yr) 70.3 ± 3.8 68.3 ± 2.6 0.15
Body mass index (kg/m2) 23.6 ± 2.7 24.3 ± 3.4 0.56
Duration of anesthesia (min) 376.9 ± 134.6 351.6 ± 109.5 0.62
Ambient room temperature (°C) 23.9 ± 0.8 23.9 ± 0.7 0.98
Type of surgery
 Radical cystectomy 9 (75%) 7 (58%) 0.65
 Radical retropubic prostatectomy 3 (25%) 3 (25%) 0.33
 Radical Nephrectomy (supine position) 0 (0%) 2 (17%) 0.45

Data are expressed as the mean ± SD or numbers (percent).

Table 2
Intraoperative Data and Postoperative Outcomes
Variables Group C (n = 12) Group H (n = 12) P value
Intraoperative data
 MAC-hr 5.9 ± 2.5 5.2 ± 1.3 0.58
 Awake time (seconds) 568.7 ± 258.5 440.8 ± 204.3 0.19
 Crystalloid administered (ml) 4,200 ± 2,106 2,975 ± 1,268 0.09
 Transfusion incidence 7 (58.3%) 3 (25.0%) 0.21
 Packed RBCs administered (unit) 1.5 ± 1.4 0.4 ± 0.8 0.03
Postoperative outcomes
 Temperature at PACU (°C) 36.3 ± 0.4 36.3 ± 0.3 0.65
 Opioid administered (μg) 65.4 ± 28.7 75.0 ± 39.9 0.51
 Shivering at PACU 1 (8.3%) 1 (8.3%)

Data are expressed as the mean ± SD, or number (percent). Awake time was defined as the time from anesthetic discontinuation to the first response to a verbal command. At PACU, intravenous fentanyl was only used for opioid administration. MAC-hr: the integral of minimal alveolar concentration (MAC) by time (hr) of exposure, RBC: red blood cell, PACU: postanesthesia care unit, PaO2: partial pressure of arterial oxygen.

Changes in TC during the entire measurement period are presented in Fig. 1. TS was similarly changed in both groups, with no significant difference in any time-point between group C and group H (Fig. 2, P = 0.919). In group C, TC was significantly lower at 90, 120, and 150 minutes after skin incision compared to baseline (P < 0.001), while in group H, there was no significant TC decrease until the end of surgery (P = 0.46). Between group C and group H, TC differed at 60, 90, 120, and 150 minutes after skin incision (−0.6 [−0.7-−0.4]°C vs. −0.3 [−0.5-−0.1]°C, P = 0.022; −0.7 [−0.9-−0.5]°C vs. −0.4 [−0.7-−0.1]°C, P = 0.015; −0.9 [−1.1-−0.6]°C vs. −0.4 [−0.5-−0.2]°C, P = 0.006; and −1.0 [−1.3-−0.7]°C vs. −0.5 [−0.5-−0.1]°C, P = 0.013, respectively).
Fig. 1
Core body temperature change in group C and group H. In group C (using heat moisture exchanger, light-gray box), the core body temperature significantly decreased compared to the baseline values at 90, 120, and 150 minutes after skin incision, but in group H (using heated humidifier, dark gray box), the core body temperature did not significantly change at these time-points compared to baseline. In the vertical box-plot, the median value is indicated by a horizontal line in the box, and the upper/lower ends of the box indicate the interquartile range. *P < 0.05, compared to the baseline value, †P < 0.05, compared between group C and group H.
Fig. 2
Intraoperative skin temperature in group C and group H. Between group C (using heat moisture exchanger, light-gray box) and group H (using heated humidifier, dark gray box), there were no differences in skin temperature at any time-point. In the vertical box-plot, the median value is indicated by a horizontal line in the box, and the upper/lower ends of the box indicate the interquartile range.


In our present study, the TC decreased significantly in patients using HME, but did not change in patients using HH. Between the two groups, the difference in TC change became significant 90 minutes after skin incision, whilst the TS showed similar values across time points. These findings suggested a role for HH in intraoperative temperature management.
HME was effective in optimizing inspiratory gas, but had no beneficial effect on TC change during general anesthesia [16]. However, HH can directly supply convective heat energy and humidified gas to the tracheobronchial tree, which consequently reduces evaporation from mucosal surfaces. The proportion of heat loss from the respiratory tract is known to be < 10% of the total intraoperative heat loss [17], but the large surface area of tracheobronchial tree may allow for effective delivery of heat energy from warmed inspiratory gas. Moreover, heat loss from mucosal vaporization can decrease > 50% in fully humidified gas [17], which may also contribute to decreased heat loss. Therefore, despite the relatively small proportion of total intraoperative heat loss, directly providing heat energy to the lower respiratory tract via HH may effectively limit TC decrease to < 0.5°C.
Intraoperative TC is known to decrease in two different phases. After anesthesia is induced, TC decreases quickly via core-to-peripheral heat redistribution by anesthetic-induced peripheral vasodilation (phase 1) [1,18-20]. Then, TC decreases slowly by heat loss via convection and radiation (phase 2) [14,20]. In phase 1, anesthetic-induced peripheral vasodilation can make prompt heat redistribution while preserving body heat content constantly and result in TS increase [21]. Our data showed that the TS change during surgery was similar between group H and group C, suggesting that initial peripheral vasodilation did not differ between these groups. In phase 2, the negative balance between heat production and loss was a major cause of TC decrease [1], and peripheral vasodilation in phase 1 subsequently can also contribute to TC decrease [22]. In elderly patients, decreases in both heat production and thermoregulated vasoconstriction may be responsible for the increased risk of intraoperative hypothermia [9]. Thus, we hypothesized that the role of HH on TC decrease is more important in phase 2 than in phase 1 when the ability of heat production is compromised. HH can provide heated inspiratory gas, thereby reducing the temperature gradient between inspiratory and expiratory airflow during mechanical ventilation. Moreover, by maintaining optimal relative humidity, HH may contribute to preventing heat loss via mucosal evaporation. In this regard, by reducing heat loss in the lower respiratory tract, HH may have a superior effect on maintaining TC, particularly in phase 2. In our current study, TC was maintained in group H even at 90 minutes after skin incision, but was significantly decreased in group C.
Intraoperative hypothermia has been associated with increased perioperative morbidity including delayed emergence and increased blood loss [5]. Particularly in elderly patients with decreased thermoregulatory response and drug metabolism, inadvertent hypothermia can cause serious postoperative complications [9,23]. However, our present data showed that emergence time, defined as the time from discontinuation of volatile anesthetics to the first response to a verbal command, was not statistically different between the two groups. Mild intraoperative hypothermia can inhibit platelet aggregation, thereby increasing risk of transfusion [13]. Although the fact that HH is associated with decreased transfusion [12,24,25], and that our data showed a significant amount of administered RBC, our results did not provide sufficient clinical evidence of the role of HH on decreased transfusion due to the relatively small sample size and different proportion of surgery types. Further studies with larger sample sizes are needed to investigate the incidence of postoperative complications.
Several previous studies have reported the effect of HH on the prevention of intraoperative hypothermia, but such studies included cases undergoing specialized surgical conditions such as liver transplantation [15] or did not monitor esophageal temperature as an indication of TC [12,13]. In contrast, in our present study, we monitored esophageal temperature, which is a well-known indicator of TC [1] and focused to the effect in elderly patients. Because TC normally decreases more than 0.5°C during phase 1 [1], the small difference in intraoperative TC change between the two groups in the present study, which was less than 0.5°C, may be clinically important in terms of maintenance of intraoperative temperature homeostasis [7,8]. Elderly patients have decreased skeletal muscle mass, resulting in both lower resting metabolic rate [26] and impaired metabolic response to cold stimulus [27]. Moreover, even in the awakened state, TC may not be maintained because of reduced vasoconstriction response to cold stress [7]. Therefore, elderly patients are more vulnerable to intraoperative hypothermia than younger patients, and the effect of warming devices on maintaining TC during general anesthesia of elderly patients can be important. Our results suggest the usefulness of HH for preventing intraoperative hypothermia.
There were possible limitations to this study of note. First, despite the significant difference in TC between the two groups, the main outcome did not support our hypothesis. Thus, the results of our present study can be regarded as preliminary only and should be interpreted carefully. Intravenous administration of warmed fluid and application of PEEP [28] may have contributed to the relatively small difference in TC in the present study. Moreover, the number of cases of radical cystectomy, which involves intestinal manipulation, was different between the two groups, which may also contribute to the results. However, our study particularly focused on the phases of TC decrease and suggested the role of HH in intraoperative temperature management. Second, although our positive result revealed the usefulness of HH in preventing TC decrease, its effectiveness is still controversial and should not be overestimated. Previous studies showed that forced-air warming system [19], as well as warmed intravenous fluid [29] were more effective on intraoperative TC decrease than HH. Therefore, HH should not be considered a novel device and may contribute, among other various warming techniques, to preventing intraoperative hypothermia.
In conclusion, HH is helpful in preventing TC decrease in elderly patients, particularly a phase 2 TC decrease. Although the present results indicate that HH use is effective during general anesthesia in elderly patients, the results should be interpreted prudently, and further studies with larger populations are needed to substantiate its use in clinical practice.


1. Sessler DI. Temperature monitoring and perioperative thermoregulation. Anesthesiology 2008; 109: 318-38. PMID: 10.1097/ALN.0b013e31817f6d76. PMID: 18648241. PMID: PMC2614355.
crossref pmid pmc
2. Sessler DI. Mild perioperative hypothermia. N Engl J Med 1997; 336: 1730-7. PMID: 10.1056/NEJM199706123362407. PMID: 9180091.
crossref pmid
3. Cereda M, Maccioli GA. Intraoperative temperature monitoring. Int Anesthesiol Clin 2004; 42: 41-54. PMID: 10.1097/00004311-200404220-00005. PMID: 15087740.
crossref pmid
4. Stone DR, Downs JB, Paul WL, Perkins HM. Adult body temperature and heated humidification of anesthetic gases during general anesthesia. Anesth Analg 1981; 60: 736-41. PMID: 10.1213/00000539-198110000-00008. PMID: 7197477.
crossref pmid
5. Sessler DI. Complications and treatment of mild hypothermia. Anesthesiology 2001; 95: 531-43. PMID: 10.1097/00000542-200108000-00040. PMID: 11506130.
crossref pmid
6. Frank SM, Fleisher LA, Breslow MJ, Higgins MS, Olson KF, Kelly S, et al. Perioperative maintenance of normothermia reduces the incidence of morbid cardiac events. A randomized clinical trial. JAMA 1997; 277: 1127-34. PMID: 10.1001/jama.277.14.1127. PMID: 9087467.
crossref pmid
7. Degroot DW, Kenney WL. Impaired defense of core temperature in aged humans during mild cold stress. Am J Physiol Regul Integr Comp Physiol 2007; 292: R103-8. PMID: 10.1152/ajpregu.00074.2006. PMID: 17197640.
crossref pmid
8. Macario A, Dexter F. What are the most important risk factors for a patient’s developing intraoperative hypothermia? Anesth Analg 2002; 94: 215-20. PMID: 10.1097/00000539-200201000-00042. PMID: 11772832.
crossref pmid
9. Jin F, Chung F. Minimizing perioperative adverse events in the elderly. Br J Anaesth 2001; 87: 608-24. PMID: 10.1093/bja/87.4.608. PMID: 11878732.
crossref pmid pdf
10. Hasegawa K, Negishi C, Nakagawa F, Ozaki M. Core temperatures during major abdominal surgery in patients warmed with new circulating-water garment, forced-air warming, or carbon-fiber resistive-heating system. J Anesth 2012; 26: 168-73. PMID: 10.1007/s00540-011-1306-1. PMID: 22189652. PMID: PMC3328673.
crossref pmid
11. Taguchi A, Ratnaraj J, Kabon B, Sharma N, Lenhardt R, Sessler DI, et al. Effects of a circulating-water garment and forced-air warming on body heat content and core temperature. Anesthesiology 2004; 100: 1058-64. PMID: 10.1097/00000542-200405000-00005. PMID: 15114200. PMID: PMC1409744.
crossref pmid pmc
12. Lee HK, Jang YH, Choi KW, Lee JH. The effect of electrically heated humidifier on the body temperature and blood loss in spinal surgery under general anesthesia. Korean J Anesthesiol 2011; 61: 112-6. PMID: 10.4097/kjae.2011.61.2.112. PMID: 21927679. PMID: PMC3167128.
crossref pmid pmc pdf
13. Yam PC, Carli F. Maintenance of body temperature in elderly patients who have joint replacement surgery. A comparison between the heat and moisture exchanger and heated humidifier. Anaesthesia 1990; 45: 563-5. PMID: 10.1111/j.1365-2044.1990.tb14832.x.
crossref pmid
14. Shanks CA. Heat balance during surgery involving body cavities. Anaesth Intensive Care 1975; 3: 114-7. PMID: 1155752.
crossref pmid
15. Han SB, Gwak MS, Choi SJ, Kim MH, Ko JS, Kim GS, et al. Effect of active airway warming on body core temperature during adult liver transplantation. Transplant Proc 2013; 45: 251-4. PMID: 10.1016/j.transproceed.2012.05.088. PMID: 23375310.
crossref pmid
16. Johansson A, Lundberg D, Luttropp HH. The effect of heat and moisture exchanger on humidity and body temperature in a low-flow anaesthesia system. Acta Anaesthesiol Scand 2003; 47: 564-8. PMID: 10.1034/j.1399-6576.2003.00108.x. PMID: 12699514.
crossref pmid
17. Graff TD, Benson DW. Systemic and pulmonary changes with inhaled humid atmospheres: clinical application. Anesthesiology 1969; 30: 199-207. PMID: 10.1097/00000542-196902000-00017.
crossref pmid
18. Matsukawa T, Sessler DI, Sessler AM, Schroeder M, Ozaki M, Kurz A, et al. Heat flow and distribution during induction of general anesthesia. Anesthesiology 1995; 82: 662-73. PMID: 10.1097/00000542-199503000-00008. PMID: 7879935.
crossref pmid
19. Hynson JM, Sessler DI. Intraoperative warming therapies: a comparison of three devices. J Clin Anesth 1992; 4: 194-9. PMID: 10.1016/0952-8180(92)90064-8.
crossref pmid
20. Díaz M, Becker DE. Thermoregulation: physiological and clinical considerations during sedation and general anesthesia. Anesth Prog 2010; 57: 25-32. PMID: 10.2344/0003-3006-57.1.25. PMID: 20331336. PMID: PMC2844235.
crossref pmid pmc
21. Sessler DI. Perioperative heat balance. Anesthesiology 2000; 92: 578-96. PMID: 10.1097/00000542-200002000-00042. PMID: 10691247.
crossref pmid
22. Hart SR, Bordes B, Hart J, Corsino D, Harmon D. Unintended perioperative hypothermia. Ochsner J 2011; 11: 259-70. PMID: PMC3179201.
pmid pmc
23. Kurz A, Plattner O, Sessler DI, Huemer G, Redl G, Lackner F. The threshold for thermoregulatory vasoconstriction during nitrous oxide/isoflurane anesthesia is lower in elderly than in young patients. Anesthesiology 1993; 79: 465-9. PMID: 10.1097/00000542-199309000-00008. PMID: 8363070.
crossref pmid
24. Winkler M, Akça O, Birkenberg B, Hetz H, Scheck T, Arkiliç CF, et al. Aggressive warming reduces blood loss during hip arthroplasty. Anesth Analg 2000; 91: 978-84. PMID: 10.1097/00000539-200010000-00039. PMID: 11004060.
crossref pmid
25. 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: 289-92. PMID: 10.1016/S0140-6736(96)90466-3.
crossref pmid
26. Falk B, Bar-Or O, Smolander J, Frost G. Response to rest and exercise in the cold: effects of age and aerobic fitness. J Appl Physiol (1985) 1994; 76: 72-8.
crossref pmid
27. Horvath SM, Radcliffe CE, Hutt BK, Spurr GB. Metabolic responses of old people to a cold environment. J Appl Physiol 1955; 8: 145-8.
crossref pmid
28. An TH, Yang JW. Effects of PEEP on the thermoregulatory responses during TIVA in patients undergoing tympanoplasty. Korean J Anesthesiol 2011; 61: 302-7. PMID: 10.4097/kjae.2011.61.4.302. PMID: 22110883. PMID: PMC3219776.
crossref pmid pmc pdf
29. Kim E, Lee SY, Lim YJ, Choi JY, Jeon YT, Hwang JW, et al. Effect of a new heated and humidified breathing circuit with a fluid-warming device on intraoperative core temperature: a prospective randomized study. J Anesth 2015; 29: 499-507. PMID: 10.1007/s00540-015-1994-z. PMID: 25771760.
crossref pmid pdf

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