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Clinical Trial/Experimental Study

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Medicine®

Warming with a composite warming strategy reduces intraoperative hypothermia in patients undergoing open hepatectomy for liver cancer A randomized controlled study Nianxun Yi, MDa, Zhangling Wang, MDa, Ran Cui, MDa,*

Abstract Background: This study investigated the application of a composite warming strategy in the perioperative care of patients who underwent open hepatectomy for liver cancer. The clinical efficacy of the composite warming strategy was observed and analyzed, and the factors causing hypothermia were discussed.

Methods: From January 2020 to December 2021, 80 patients were selected for the study. The control group adopted perioperative forced-air warming measures, while the experimental group implemented a composite warming strategy. The clinical data of the 2 groups of patients were compared, and the factors influencing intraoperative hypothermia were explored.

Results: The incidence of hypothermia in the composite warming strategy group was significantly lower than that in the forced- air warming group (P = .015). There were no significant differences in sex, age, BMI, stage of liver cancer, presence of liver cirrhosis, chronic hepatitis, history of alcohol consumption, PLT, PT, pain score, length of hospital stay, etc, between the 2 groups (P > .05). However, there were significant differences in intraoperative fluid volume, anesthesia time, intraoperative blood loss, and PACU observation time (P < .05). Multivariate analysis revealed that intraoperative blood loss, intraoperative fluid replacement volume, and operation time were factors influencing intraoperative hypothermia (P < .05).

Conclusion: The composite warming strategy plays a role in preventing hypothermia during open hepatectomy for liver cancer. The occurrence of hypothermia during open hepatectomy for liver cancer patients is related to intraoperative blood loss, intraoperative fluid replacement volume, and anesthesia time.

Abbreviations: ASA = American Society of Anesthesiologists, BMI = body mass index, NRS = the numeric rating scale, PACU = post-anesthesia care unit, PLT = platelet, PT = prothrombin time, ROC = receiver operating characteristic, VAS = visual analog scale.

Keywords: composite warming strategy, intraoperative hypothermia, open hepatectomy for liver cancer

1. Introduction Perioperative hypothermia, a clinical condition character- ized by a reduction in core body temperature to below 36 °C during the perioperative phase, is a prevalent complication in the context of anesthesia and open abdominal surgical proce- dures. This state precipitates an assortment of perioperative complications, including but not limited to surgical site infec- tions, cardiac arrhythmias, and heart blockages.[1] Further complications include postoperative shivering, enhanced blood loss, prolonged and variable impacts of anesthetic

agents, coagulation disturbances, extended durations in the post-anesthesia care unit (PACU), and increased perceptions of pain.[2–4]

In the realm of surgical procedures, open hepatectomy, a frontline treatment modality for early-stage liver cancer,[5] is associated with a unique susceptibility to hypothermia. This increased risk is attributable to a variety of factors, includ- ing the lengthy duration of surgical intervention, the expan- sive operative field, and the liver’s diminished heat production capacity. Patients with liver cancer are particularly vulnerable to

This study was supported by the Neijiang City Bureau of Science and Technology Project (2021. Grant No. 38).

The authors have no conflicts of interest to disclose.

The authors declare that the research was conducted in accordance with ethical guidelines and approved by the relevant institutional review board or ethics committee. All participants provided informed consent where applicable.

All data generated or analyzed during this study are included in this published article [and its supplementary information files].

The study was approved by the ethics review board of First People’s Hospital of Neijiang City and was registered with ClinicalTrials.gov, NCT06766773. a Department of Anesthesia, The First People’s Hospital of Neijiang, Neijiang, China.

* Correspondence: Ran Cui, Department of Anesthesia, The First People’s Hospital of Neijiang, Neijiang 641000, China (e-mail: [email protected]).

Copyright © 2025 the Author(s). Published by Wolters Kluwer Health, Inc. This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial License 4.0 (CCBY-NC), where it is permissible to download, share, remix, transform, and buildup the work provided it is properly cited. The work cannot be used commercially without permission from the journal.

How to cite this article: Yi N, Wang Z, Cui R. Warming with a composite warming strategy reduces intraoperative hypothermia in patients undergoing open hepatectomy for liver cancer: A randomized controlled study. Medicine 2025;104:8(e41616).

Received: 13 November 2023 / Received in final form: 1 February 2025 / Accepted: 3 February 2025

http://dx.doi.org/10.1097/MD.0000000000041616

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the deleterious effects of hypothermia, this susceptibility often compounded by preexisting liver function impairment. This can exacerbate the risk of coagulation dysfunction and electrolyte imbalance during the operation.[6–10]

Given the potential to enhance the efficiency of postoperative recovery, the imperative to prevent hypothermia during open hepatectomy procedures remains a critical area of clinical focus. The current mainstay of hypothermia prevention in the clinical setting is the forced-air warming system, which is favored for its user friendliness, cost effectiveness, safety, and efficacy.[11,12] However, the applicability of this system is contingent primarily upon the body surface area it covers, limiting its effectiveness in thoracic and abdominal surgeries.[13,14]

Notably, a gap exists in the current body of literature with respect to evaluating the efficacy of warming strategies spe- cific to patients undergoing open hepatectomy. This deficiency restricts our understanding and ability to implement effective warming strategies for this specific cohort of surgical patients. Despite the well-documented benefits of the forced-air warming system, its limitations in terms of operative area coverage, par- ticularly in procedures such as open hepatectomy, cast doubt on its effectiveness. Understanding the unique risk factors for hypothermia in open hepatectomy patients is an essential pre- requisite for the development of effective warming strategies tailored to this patient population. Furthermore, given the par- ticular sensitivity of liver cancer patients to the adverse effects of hypothermia due to existing liver function impairment, there is a compelling need for interventions that take into account the overall health status of the patient, potentially offering a more effective approach to managing hypothermia risk.

Therefore, despite the widespread clinical adoption of the forced-air warming system, its effectiveness in preventing hypo- thermia during open hepatectomy procedures – given the unique risk factors associated with this surgical intervention – remains uncertain. Research aimed at evaluating and developing warm- ing strategies specifically tailored for patients undergoing open hepatectomy is urgently needed, given the distinct vulnerability of these patients to the damaging effects of hypothermia.

In our study, we investigated the practicability and effective- ness of a composite warming strategy during open hepatectomy. Additionally, we conducted a quantitative correlation study on the occurrence rate of hypothermia during this procedure. Our findings suggest that the composite warming strategy may have better outcomes than the forced-air warming system in terms of anesthesia duration, blood loss, fluid replacement volume, and duration of PACU observation. This provides evidence-based guidance for hypothermia prevention during surgery. This research also highlights the potential of a potential, viable, and successful nursing strategy for preventing hypothermia during open hepatectomy, which could be employed in a wider range of open abdominal surgeries.

2. Methods

2.1. Patient selection

We conducted a prospective, single-blind, randomized study of 80 patients who underwent elective open hepatectomy for hepa- tocellular carcinoma from January 2020 to December 2021. All patients meet the inclusion and exclusion criteria. The patients were blinded to their treatment allocation; however, the medical team performing the surgeries and the researchers collecting the data were likely aware of which treatment each patient received. Patients were eligible for inclusion in the study if they met the following criteria: aged between 18 and 75 years and had elec- tive open hepatectomy scheduled for the treatment of hepatocel- lular carcinoma, confirmed by preoperative biopsy or imaging. This study is registered with ClinicalTrials.gov, NCT06766773.

Adequate liver function was determined by a Child–Pugh score of A or B; an American Society of Anesthesiologists physical

status classification of I, II, or well-controlled III; and the provi- sion of informed consent for participation in the research study. Patients who met any of the following criteria were excluded: were aged under 18 or over 75 years, had metastatic liver disease or required emergency liver surgery, had chronic analgesic use for pain management that could interfere with pain assessment, participated in another clinical trial within the previous 30 days, had contraindications to the use of warming devices, such as certain skin conditions or advanced peripheral vascular disease, or were pregnant or lactating. The presence of an implantable device that could be affected by warming strategies, such as pacemakers or defibrillators; cognitive impairment or psychi- atric disorders that could compromise the understanding of the study or informed consent; the use of medications or substances known to impact thermoregulation, including illicit drugs, alco- hol abuse, and antipyretics; a history of malignancies other than liver cancer that could influence survival or perioperative risk; a recent history (within the past 6 months) of myocardial infarc- tion or cerebrovascular accident; uncontrolled diabetes mellitus or other significant endocrine disorders; and severe anemia with hemoglobin levels below a predetermined threshold, potentially affecting oxygen transport and thermoregulation. The selection process was designed to create a homogeneous patient cohort while ensuring patient safety and preserving the integrity of the study findings. Patients were divided into 2 groups according to the use of different warming strategies on the basis of the computer-generated random number list. Informed consent was obtained from each patient prior to surgery. Of the initial 80 patients, 74 were ultimately included in the study. Our random- ized controlled trial was funded by the Neijiang City Bureau of Science and Technology Project.

2.2. Intraoperative body temperature monitoring

Following the commencement of the surgery, a temperature monitoring device (a disposable medical temperature sensor, pro- vided by Yixin Medical New Technology Co., Ltd.) was inserted into the patient’s nasopharynx to record core temperature, while the water blanket and forced-air warming system were activated. Body temperature was recorded every 5 minutes. However, due to the long duration of the operation, we analyzed temperature changes every half hour. In the post anesthesia care unit (PACU), the core body temperature of the patients was measured at 3 time points (time point 1 [upon arrival at the PACU], time point 2 [30 minutes after PACU care], and time point 3 [upon trans- fer from the PACU]) using an infrared ear thermometer (Braun Thermo Scan PRO 6000) at the tympanic membrane.

2.3. Measurement of blood volume loss

The surgical procedure involved the use of a pre-heparinized suction system (25,000 IU of heparin in saline solution) to col- lect and record blood loss efficiently. This system was benefi- cial for preventing clot formation due to the continuous flow of the saline solution. The exact amounts of heparin and saline solutions utilized were meticulously documented. Any remain- ing intraperitoneal losses were aspirated through surgical drains into a designated canister at the culmination of the surgical pro- cedure. The total fluid volume within the canister was quantified using a system capable of discerning differences up to ± 10 mL. The blood volume loss was calculated by subtracting the vol- ume of the added heparin and saline solutions from the total volume collected in the surgical canister.

2.4. Measurement of pain

Pain scores were evaluated by the nurses in the PACU as the patients gradually regained consciousness. The numeric rat- ing scale and the visual analog scale were used to measure

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participants’ pain levels. These scales have been proven to be reli- able and valid tools for pain assessment. Patients were instructed to rate their pain on a Likert scale from 0 to 10, with 0 repre- senting no pain and 10 representing the worst imaginable pain.

2.5. Surgical procedure

All surgeries were performed by the same experienced hepato- biliary surgery team in our hospital. The room temperature was maintained at 24 to 26 °C during the operation. The intraop- erative irrigation solution was heated to 37 °C in a multifunc- tional incubator (FYL-YS-100 L, produced by Beijing Fuyilian Electric Co., Ltd.) for use during operation. The patients were randomly divided into 2 groups. The trial group was subjected to the composite warming strategy (n = 37); the temperature of the operating room was preheated to 24 to 26 °C 30 minutes before the operation, and the patients were covered with a quilt after entering the room. The operating table was covered with a warm water blanket (Tianjin Akefer Technology Development Co., Ltd.), the working temperature was set to 38 °C, and a disposable cotton sheet was used to cover the working tempera- ture. A forced-air heating system was used (WU-505; Jiangmen Dacheng Medical Devices Co., Ltd.). The working temperature was set at 38 to 40 °C, and the patient’s body temperature was raised to 36.5 °C by using a heating blanket in the recovery room after anesthesia (PACU) and the control group (n = 37; with the same operating room conditions, only the forced heated air sys- tem was used during the operation, and the body temperature was recovered and observed in the recovery room after anesthe- sia). To avoid skin burns, the plants were not allowed to touch the skin at a temperature >41.0 °C (Fig. 1).

2.6. Data collection

The primary outcome was intraoperative temperature changes. We compared intraoperative bleeding volume, coagulation function, pain indices, anesthesia time, PACU observation time, etc, between the 2 patient groups. The secondary outcome was the incidence of complications. The intensity of postoperative pain in patients was assessed using a visual analog pain scale.

2.7. Data statistics and analysis

All the statistical analyses were performed using SPSS 26.0 (Chicago). The data were prospectively collected using a com- puterized database. Quantitative data are presented as the mean ± standard deviation or median (M). We analyzed the data using an independent sample t test, 1-way analysis of variance, the chi-square test (one-sided) and Fisher exact test (one-sided). We then constructed receiver operating characteristic (ROC) curves to determine the optimal cutoff values for each index. Subsequently, we grouped the corresponding indices based on these cutoff values and included these data in a multivariate logistic regression model to screen for risk factors causing intra- operative hypothermia. A P value < .05 was considered to indi- cate statistical significance.

3. Results

3.1. Basic information of patients in the composite warming strategy group and the forced-air warming group

Among the 74 patients, 8 in the composite warming strategy group and eighteen in the forced-air warming group experienced hypothermia. Table 1 presents the basic clinical information and intraoperative management of the 2 groups, revealing no sta- tistically significant differences in terms of sex, age, BMI, liver cancer stage, presence of cirrhosis, chronic hepatitis, alcohol consumption history, PLT count, PT, pain rating, or length of hospital stay (P > .05). However, the incidence of hypothermia, intraoperative fluid volume, surgical duration, intraoperative blood loss, and duration of PACU observation were significantly different (P < .05).

3.2. Comparison of intraoperative and PACU temperature changes in the two groups

The core temperature changes in both groups are depicted in Figure 2. The composite warming strategy group began to differ from the forced-air warming group after 210 minutes (P > .05). From 180 minutes onward until the end of the PACU

Figure 1. Trial flow chart.

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observation, the differences gradually stabilized, and a signifi- cant difference appeared (P < .05) (Table 2).

3.3. Comparison of postoperative complications in both groups

We employed the Clavien–Dindo classification to assess post- operative complications in both patient groups, as shown in

Table 1.[15,16] The main postoperative complications in both groups were Grades I and II, and there was no significant differ- ence in the complication grade (P = .157).

In the composite warming strategy group, Grade I complica- tions included 2 instances of vomiting, 2 instances of vomiting accompanied by incision pain, and 2 instances of fever. These complications improved after symptomatic treatment. Grade II complications included 1 patient requiring postoperative blood transfusion and 3 patients with fever and local inflammation at

Table 1

Baseline characteristics and intraoperative management.

Composite warming Forced-air warming P

Baseline characteristics Sex Male 20 19 .816 Female 17 18 Mean age, yr (SD) 44 (10) 43 (8) .206 Mean body-mass index, kg/m2 (SD) 24 (3) 25 (3) .163 Staging of liver cancer Stage I 18 16 .641 Stage II 19 21 Cirrhosis 19 17 .642 Chronic hepatitis 24 20 .344 Hypertension 11 10 .799 Diabetes mellitus type 2 6 4 .499 Chronic kidney disease 2 1 .556 A history of cardiovascular disease 6 8 .556 Previous abdominal or hepatic surgeries 3 2 .644 Mean PLT count (SD) 144 (30) 146 (33) .446 Mean PT, second (SD) 11 (1) 11 (1) .578 Mean anesthesia time, min (SD) 228 (18) 250 (25) .002 Mean intraoperative infusion volume, mL (SD) 913 (200) 1473 (143) .035 Mean postoperative hospitalization time, d (SD) 6 (2) 6 (2) .741 Mean intraoperative bleeding volume, mL (SD) 192 260 <.001 Incidence of hypothermia (%) 8 (21.6%) 18 (48.6%) .015 Mean PACU time, min (SD) 20 (5) 29 (8) .017 Mean pain score (SD) 4 (2) 6 (2) .848 Clavien–Dindo grade I 9 12 .157 II 6 7 IIIa 3 2 IIIb 1 2 IVa 0 1

PACU = post-anesthesia care unit, PLT = platelet, PT = prothrombin time, SD = standard deviation.

Figure 2. Intraoperative temperature changes.

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the window site. Additionally, 1 patient with Grade IIIa com- plications required local anesthesia abdominal puncture, and 1 patient with Grade IIIb complications underwent a second surgery due to bleeding on the second postoperative day.

In the forced-air warming group, Grade I complications included 2 instances of vomiting, 3 instances of incision pain, and 4 instances of fever. These complications improved after symptomatic treatment. Grade II complications included 4 cases requiring postoperative blood transfusion and 2 cases of biliary fistula (the patients were discharged with a drain without any special treatment). Additionally, there were 2 cases of Grade IIIa complications requiring local anesthesia abdominal punc- ture, 2 cases of Grade IIIb complications requiring a second surgery due to bleeding on the second postoperative day, and 1 case of Grade IVa complication leading to acute liver failure on the fifth postoperative day and receiving dialysis treatment. No patients in either group died within 30 days postoperatively.

3.4. Risk factor analysis for the occurrence of hypothermia

Given that the forced-air heating system remains the preeminent choice for intraoperative insulation in clinical practice, we con- ducted a comparative analysis of the forced-air warming group to determine the risk factors for the occurrence of hypothermia. The study focused on the hypothermia and normal temperature subgroups within the forced-air warming group. Significant dif- ferences were observed in critical parameters such as intraopera- tive fluid volume, anesthesia time, and intraoperative blood loss (P < .05), as listed in Table 3.

For the aforementioned 3 factors, the results of the ROC curve analysis showed that the area under the curve for intraoperative blood loss, surgical duration, and intraoperative fluid volume were 0.8348, 0.8231, and 0.7193, respectively (Table 4 and Fig. 3).

By using the Youden index, we determined the following opti- mal cutoff points: anesthesia time of 265 minutes, intraopera- tive blood loss of 245 mL, and intraoperative fluid volume of 1535 mL. Based on these cutoff points, we classified intraoper- ative blood loss, surgical duration, and intraoperative fluid vol- ume and incorporated these classifications into the multivariate analysis model.

Univariate analysis revealed intraoperative blood loss, fluid volume, and anesthesia duration as risk factors for intraopera- tive hypothermia. This was corroborated by multivariate analy- sis, which confirmed that an intraoperative blood loss of 245 mL or more, an intraoperative fluid volume of 1535 mL or greater, and a surgical duration extending 265 minutes or beyond inde- pendently contributed to the risk of intraoperative hypothermia (P < .05) (Table 5).

4. Discussion The present study examined the implications of a compos- ite warming strategy, as opposed to conventional forced-air

warming, in the context of open abdominal liver cancer resection surgery. The focus was primarily on the incidence of periopera- tive hypothermia and surgical complications. A clinical trial was conducted using a randomized design, and the results revealed a significantly decreased incidence of perioperative hypother- mia in patients who underwent composite warming strategies, especially in surgeries exceeding 3 hours. This composite warm- ing strategy effectively mitigated heat loss from the core to the periphery, maintaining the temperature of the core organs. This phenomenon has advantageous implications for vascular tension regulation and perfusion.[17–20] Furthermore, patients subjected to the composite warming strategy experienced less postoperative pain, shorter durations of surgery and PACU observation, and fewer postoperative complications. The study also pinpointed anesthesia time, intraoperative fluid volume, and blood loss as potential high-risk factors for hypothermia.

Open abdominal liver cancer resection remains 1 of the lim- ited options for patients diagnosed with primary liver malignan- cies. The liver, a significant heat-producing and metabolic organ, has a high hypothermia incidence rate of up to 70% under unwarmed conditions, similar to that of other noncardiac sur- geries.[1,21] This high incidence rate is associated with a greater number of postoperative complications.[22] This study proposes a composite warming strategy that combines forced-air warming with water blanket warming, preoperative operating room heat- ing, and rapid sequential postoperative warming. This approach counteracts the potential shortcomings of relying exclusively on forced-air warming in open abdominal surgeries and results in a decreased hypothermia incidence rate of 21.6%, compared to 48.6% in the forced-air warming group. This difference was par- ticularly noticeable for surgeries lasting more than 3 hours.

This study further proposed a strategy to compensate for the poor performance of forced-air warming in abdominal surger- ies. This strategy included a combination of a water blanket and preoperative room warming, followed by rapid postoperative rewarming. The resulting decrease in the temperature gradient from the core to the periphery minimized heat flow from the core to the periphery following anesthesia-induced vasodilation. This strategy ensured a relatively stable body temperature through- out the procedure, which is vital for maintaining vascular ten- sion and organ perfusion, thereby reducing the adverse effects of hypothermia during surgery. Notably, the improved warming strategy did not augment the incidence of complications.

Maintenance of a relatively stable perioperative body tempera- ture is critical for surgical efficacy. Single-factor and multifactor analyses were also conducted on high-risk factors for hypothermia, with blood loss, surgery duration, and intraoperative fluid volume identified as independent factors. In this study, patients with blood loss exceeding 245 mL were found to have an increased risk of hypothermia. The liver, a richly perfused organ often infiltrated by tumors, may experience considerable bleeding despite advance- ments in medical technology aimed at controlling hemorrhage.

Extensive fluid replacement during surgery emerged as another independent risk factor for hypothermia. An increase in

Table 2

Comparison of temperature changes between 2 groups.

0 min 30 min 60 min 90 min 120 min 150 min 180 min 210 min

36.72 ± 0.06 36.55 ± 0.08 36.47 ± 0.1 36.41 ± 0.11 36.38 ± 0.15 36.33 ± 0.18 36.31 ± 0.21* 36.21 ± 0.24* 36.71 ± 0.06 36.44 ± 0.08 36.36 ± 0.1 36.25 ± 0.11 36.15 ± 0.12 36.02 ± 0.13 35.88 ± 0.15* 35.75 ± 0.17*

240 min 270 min PACU 0 min 15 min 30 min F interblock F time F mutually

36.15 ± 0.25* 36.24 ± 0.25* 36.26 ± 0.21* 36.46 ± 0.16* 36.7 ± 0.14* 59.511** 688.799** 112.43** 35.57 ± 0.21* 35.58 ± 0.22* 35.68 ± 0.18* 35.78 ± 0.16* 35.8 ± 90.14*

PACU = post-anesthesia care unit. * The ratio of T1 to the same group P < .05. ** P < .01.

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the volume of fluid replaced can induce a “cold dilution effect,” leading to a decrease in body temperature.[23,24] As the dura- tion of surgery increases, the risk of hypothermia increases. In addition to the decrease in body temperature due to surgical operation and the use of rinsing fluids, the administration of

anesthetics and an increase in blood loss and fluid volume can trigger a series of physiological reactions that potentially exac- erbate the incidence of hypothermia.

Although the difference in pain experienced by patients in the compound insulation group and the control group was not

Table 3

Baseline characteristics and intraoperative management of the hypothermia and normal temperature groups.

Hypothermia Normal temperature P

Baseline characteristics Sex Male 10 9 .618 Female 8 10 Mean age, yr (SD) 41 (6) 41 (6) .951 Mean body-mass index, kg/m2 (SD) 23 (2) 24 (2) .303 Staging of liver cancer Stage I 9 7 .638 Stage II 9 12 Cirrhosis 7 9 .419 Chronic hepatitis 8 11 .63 Intraoperative management Mean PLT count (SD) 143 (13) 149 (13) .153 Mean PT, s (SD) 12 (1) 12 (1) .282 Mean anesthesia time, min (SD) 253 (12) 228 (12) .01 Mean intraoperative infusion volume, mL (SD) 1446 (70) 1402 (50) .042 Mean postoperative hospitalization time, d (SD) 7 (2) 6 (1) .415 Mean intraoperative bleeding volume, mL (SD) 261 (41) 245 (28) .028 Mean PACU time, min (SD) 29 (4) 25 (2) .09 Mean pain score (SD) 7 (1) 6 (1) .063 Clavien–Dindo grade I 6 3 .124 II 4 2 IIIa 1 1 IIIb 1 1 IVa 1 0

PACU = post-anesthesia care unit, PLT = platelet, PT = prothrombin time, SD = standard deviation.

Table 4

Diagnostic efficacy of intraoperative blood loss, intraoperative infusion and anesthesia time for hypothermia.

Diagnostic efficiency index Intraoperative bleeding volume Intraoperative infusion volume Anesthesia time

Area under ROC curve 0.8231 0.7193 0.8289 Youden index (%) 40.6 34.51 46.2 Sensitivity (%) 68.42 78.95 68.42 Specificity (%) 72.22 55.56 77.78 Optimal boundary point 245 mL 1535 265 min

ROC = receiver operating characteristic.

Figure 3. ROC curve of each index. ROC = receiver operating characteristic.

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statistically significant, we believe that pain is a significant con- cern in the context of open hepatectomy for liver cancer and has potential implications for patient prognosis. The experience of pain is not only a subjective discomfort but also a physiological stressor that can trigger a myriad of physiological responses, par- ticularly in the immune and endocrine systems.[25] This, in turn, could impact the healing process, the risk of postoperative com- plications, and, ultimately, patient outcomes. Acute postoperative pain, if poorly managed, can lead to chronic postsurgical pain, a condition affecting a significant proportion of patients following major surgery.[26,27] Studies suggest that chronic postsurgical pain can have long-term implications for quality of life, physical func- tioning, and mental health. Furthermore, uncontrolled acute pain can lead to increased sympathetic nervous system activity, result- ing in tachycardia, hypertension, and increased cardiac work- load, which could predispose patients to cardiac complications.

This study has several limitations. First, the sample size was small, and the results only reflect the experience of a single center. Therefore, the generalizability of the research conclusions still needs to be validated by randomized controlled studies with larger sample sizes. Second, this study did not consider the possible impact of the amount of anesthetic drugs on intraoperative hypothermia. We hope to improve and supplement these limitations in follow-up studies.

5. Conclusion The composite warming strategy has a good preventive effect on hypothermia in open abdominal liver cancer resection surgery. Hypothermia can be prevented by limiting fluid volume, reduc- ing bleeding, and preventing prolonged surgery, all of which can ultimately improve patient prognosis.

Author contributions Conceptualization: Nianxun Yi. Data curation: Nianxun Yi. Investigation: Zhangling Wang. Methodology: Nianxun Yi. Software: Nianxun Yi, Zhangling Wang. Supervision: Zhangling Wang. Validation: Zhangling Wang. Visualization: Zhangling Wang. Writing – original draft: Nianxun Yi. Writing – review & editing: Ran Cui.

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Table 5

Logistic regression analysis of influencing factors of intraoperative hypothermia.

β SE Wald χ2 RR 95% CI P

Anesthesia time 245 min 0.0719 0.0333 4.6335 1.0748 1.0086 to 1.1442 .0314 Intraoperative bleeding volume 275 mL 1.3047 0.5123 6.4815 3.684 1.3358 to 10.2076 .011 Intraoperative infusion volume 1500 mL 0.0075 0.0028 7.1204 1.0075 1.0019 to 1.0132 .0076

CI = confidence interval, RR = relative risk, SE = standard error.