Effects of preoperative warming on the occurrence of surgical site infection: A systematic review and meta-analysis

Enhanced Recovery after Surgery - Evidence and Practice

AbstractEnhanced Recovery After Surgery (ERAS) is a global initiative comprised of a series of evidence-based interventions in the preoperative, intraoperative, and postoperative surgical phases. When implemented as a bundle, ERAS interventions both improve clinical outcomes and provide cost savings to the health care system. This review provides an update on the current evidence for individual ERAS elements to improve quality of care as well as practical recommendations for multidisciplinary teams to implement their own ERAS programs.

Intraoperative Hypothermia Versus Normothermia in Breast Reconstruction: A Systematic Review and Meta-Analysis

Despite advancements in breast reconstruction, the precise impact of intraoperative hypothermia on postoperative complications remains unclear. Recent literature suggests that intraoperative hypothermia is a risk factor for impaired wound healing and increases the incidence of surgical site infections. This study examines the effect of intraoperative hypothermia on postoperative outcomes in breast reconstruction. We searched PubMed, Embase, and Cochrane Library for studies comparing hypothermia with normothermia in breast reconstruction. A meta-analytical method was employed to estimate the risk of postoperative complications among patients undergoing breast reconstruction. Data synthesis employed the random-effects models, presenting the results as risk ratio (RR) with corresponding 95% confidence intervals (CIs). Statistical analysis was performed using Review Manager 5.4 (Cochrane Collaboration), and heterogeneity was assessed using I2 statistics. Four studies meeting our inclusion criteria were included in the meta-analysis, comprising 871 participants. The average age and body mass index were 52.98 years and 27.76 kg/m2, with a follow-up duration of 3-6 months. In our analysis, intraoperative hypothermia was associated with an increase in the incidence of wound healing complications in breast reconstruction (RR 1.68; 95% CI 1.24 to 2.27; p = 0.0008). Despite lower incidence of infection, hematoma, seroma, and necrosis in the hypothermia group, no significant differences were observed. Our meta-analysis assessing intraoperative hypothermia in breast reconstruction indicates that hypothermia is a significant risk factor for wound healing complications.

Hypothermia: Pathophysiology and the propensity for infection

Hypothermia in combination with infection presents a complex challenge in clinical and battlefield medicine. Multifaceted physiological and immunological consequences of hypothermia drastically change the risk, progression, and treatment of a concomitant infection. Managing hypothermia and infection in extreme cold settings is particularly relevant in an era with increased risk of military operations in Polar climates. Here, we discuss the elevated instance of infection during accidental and therapeutic hypothermia and speculate how a compromised immune system may contribute. We focus on skin and soft tissue infections and sepsis, which are among the serious infectious complications of hypothermia and battlefield injuries. We also present the challenges associated with treating infections under hypothermic conditions. Finally, we advocate for a renewed focus on identifying causal relationships between hypothermia and infection risk and assessing established infection treatment regiments in hypothermic patients to enhance trauma management and survival outcomes in hypothermia-related injuries.

Effects of different forced-air warming systems on the core temperature of patients: a manikin and multi-center clinical study

BACKGROUND

The use of forced-air warming (FAW) blankets is widely recognized for preventing shivering and hypothermia in patients under general anesthesia. Various types of products are currently available for hospitals, and we have conducted a preliminary evaluation of insulation equipment based on expert opinions and initial parameters. However, we lack real-world experiments and accurate clinical data to validate these parameters and the accuracy of our decision-making results. This study aims to confirm the effectiveness of different FAW systems by assessing the thermal protection and operational characteristics of the equipment in both experimental and clinical settings, thereby enhancing our evaluation database.

METHODS

In the manikin test, we conducted six tests including heat distribution and heating rate, heater outlet temperature stability, etc. In the clinical study, patients were randomly assigned to four groups [Group A (Bair Hugger Therapy, 3 M, St. Paul, MN, USA; 63500); Group B (EQUATOR® level I, Smith Medical ASD, MN, USA; Snuggle Warm, SW-2013); Group C (Jiang Men Da Cheng Medical Devices Co., Ltd, China; IOB-006); and Group D (Shang Hai Nest Tech Medical Materials Co., Ltd, China; BH-017)], with each group comprising 30 individuals. At the start of anesthesia induction, the FAW blanket was activated and set to 43 °C until the completion of surgery. The primary endpoint was the average core body temperature during surgery. Secondary endpoints included hemodynamic and surgical variables, adverse events, and recovery metrics.

RESULTS

In the manikin test, the observed results of the experimental parameters (heat distribution, air pressure difference, and hole observation test) for Group A are superior to those of the other groups. In the clinical study, although the mean perioperative core body temperature remained above 36 °C across all groups [Group A: 36.31 ± 0.04; Group B: 36.26 ± 0.06; Group C: 36.17 ± 0.03; Group D: 36.25 ± 0.05], patients in Group A maintained higher temperatures compared to the other groups (p < 0.001).

CONCLUSIONS

Among patients undergoing laparoscopic radical resection of colorectal cancer with general anesthesia, all four FAW systems effectively prevented perioperative hypothermia. However, the system in Group A minimized heat loss more effectively than the others, providing superior thermal protection.

TRIAL REGISTRATION

ChiCTR2200065394, 03/11/2022.

Contrasting seasonality of the incidence of incisional surgical site infection after general and gastroenterological surgery: an analysis of 8436 patients in a single institute

BACKGROUND

While seasonality of hospital-acquired infections, including incisional SSI after orthopaedic surgery, is recognized, the seasonality of incisional SSI after general and gastroenterological surgeries remains unclear.

AIM

To analyse the seasonality and risk factors of incisional SSI after general and gastroenterological surgeries.

METHODS

This was a retrospective, single-institute, observational study using univariate and multivariate analyses. The evaluated variables included age, sex, surgical approach, surgical urgency, operation time, wound classification, and the American Society of Anesthesiologists physical status (ASA-PS).

FINDINGS

A total of 8436 patients were enrolled. General surgeries (N = 2241) showed a pronounced SSI incidence in summer (3.9%; odds ratio (OR): 1.87; 95% confidence interval (CI): 1.05-3.27; P = 0.025) compared to other seasons (2.1%). Conversely, gastroenterological surgeries (N = 6195) showed a higher incidence in winter (8.3%; OR: 1.38; 95% CI: 1.10-1.73; P = 0.005) than in other seasons (6.1%). Summer for general surgery (OR: 1.90; 95% CI: 1.12-3.24; P = 0.018) and winter for gastroenterological surgery (1.46; 1.17-1.82; P = 0.001) emerged as independent risk factors for incisional SSI. Open surgery (OR: 2.72; 95% CI: 1.73-4.29; P < 0.001) and an ASA-PS score ≥3 (1.64; 1.08-2.50; P = 0.021) were independent risk factors for incisional SSI in patients undergoing gastroenterological surgery during winter.

CONCLUSION

Seasonality exists in the incisional SSI incidence following general and gastroenterological surgeries. Recognizing these trends may help enhance preventive strategies, highlighting the elevated risk in summer for general surgery and in winter for gastroenterological surgery.

The Effect of Prewarming on Perioperative Hypothermia: A Systematic Review and Meta-analysis of Randomized Controlled Studies

PURPOSE

One of the methods for maintaining perioperative normothermia is prewarming. This study was conducted to investigate the effect of a preoperative prewarming intervention on perioperative body temperature.

DESIGN

Systematic review and meta-analysis.

METHODS

A literature review was conducted using PubMed, CINAHL, Cochrane Central, Science Direct, Springer Link, Scopus, Web of Science, and Ovid databases. Randomized controlled trials that investigate the effect of prewarming on body temperature in the prevention of perioperative hypothermia were included. The review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement guidelines. Methodological quality was assessed using the Cochrane Collaboration "risk of bias" tool. Meta-analysis was performed with Comprehensive Meta-Analysis, version 2. Moderator analysis and publication bias assessment were performed. Funnel plots were analyzed using Orwin's fail-safe N, Trim, and Fill test method to investigate the source of heterogeneity.

FINDINGS

A total of 907 studies were found. The systematic review included 27 studies. Of these, 23 were included in the intraoperative meta-analysis, and 16 were included in the postoperative meta-analysis. According to the meta-analysis results, the prewarming intervention was effective in maintaining normothermia in the intraoperative (Hedge's g = 0.972, 95% confidence intervaI = 0.674 to 1.270) and postoperative (Hedge's g = 0.818, 95% confidence intervaI = 0.520 to 1.114) periods.

CONCLUSIONS

The findings of this systematic review and meta-analysis showed that preoperative prewarming played a significant role in providing and maintaining perioperative normothermia.

Exploring Thermal Dynamics in Wound Healing: The Impact of Temperature and Microenvironment

Exploring the critical role of thermal dynamics in wound healing, this manuscript navigates through the complex biological responses initiated upon wound infliction and how temperature variations influence the healing trajectory. Integrating biothermal physics, clinical medicine, and biomedical engineering, it highlights the significance of thermal management in wound care, emphasizing the wound microenvironment's division into internal and external domains and their collaborative impact on tissue repair. Innovations in real-time wound temperature monitoring, especially through intelligent wireless sensor dressings, are spotlighted as transformative, enabling precise wound condition management. The text underscores the necessity for further research to elucidate thermal regulation's molecular and cellular mechanisms on healing processes. It advocates for standardized protocols for localized heating treatments, integrating them into personalized wound care strategies to enhance therapeutic outcomes, improve patient well-being, and achieve cost-effective healthcare practices. This work presents a forward-looking perspective on refining wound management through sophisticated, evidence-based interventions, emphasizing the interplay between thermal dynamics and wound healing.

Prewarming Parturients for Cesarean Section Does Not Raise Wound Temperature But Body Heat and Level of Comfort: A Randomized Trial

PURPOSE

Prewarming before cesarean section lowers the rates of surgical site infections (SSIs). We hypothesized that this effect is explained due to a higher core temperature resulting in a higher wound temperature.

DESIGN

We conducted an open-labeled randomized study with on-term parturients scheduled for elective cesarean section under spinal anesthesia. Participants were randomized into an intervention group (prewarming) and a control group.

METHODS

Core and wound temperature, comfort level, and examination results were taken at defined times until discharge from the postanesthesia care unit (PACU). There was a follow-up visit and interview 1 day after the procedure. The primary outcome was a difference in wound temperature. The secondary outcomes were differences in core temperature, patient comfort, blood loss, SSI, and neonatal outcome.

FINDINGS

We randomized a total of 60 patients, 30 per group. Prewarming lead to a significantly higher core temperature. Additionally, patient comfort was significantly higher in the prewarming group even after discharge from PACU. We did not find a difference in wound temperature, SSI, neonatal outcome, or blood loss.

CONCLUSIONS

Prewarming before cesarean section under spinal anesthesia maintains core temperature and improves patient comfort but does not affect wound temperature.

Proceedings of the United Kingdom Periprosthetic Joint Infection Meeting 2022: Combined and Arthroplasty Sessions

Considerable variation in practice exists in the prevention, diagnosis, and treatment of periprosthetic joint infection (PJI), which is a devastating complication for patients and surgeons. The consensus principle has been increasingly embraced by the orthopaedic community to help guide practice, especially where high-level evidence remains unavailable. The third United Kingdom Periprosthetic Joint Infection (UK PJI) Meeting was held in Glasgow on April 1, 2022, with more than 180 delegates in attendance, representing orthopaedics, microbiology, infectious diseases, plastic surgery, anesthetics, and allied health professions, including pharmacy and arthroplasty nurses. The meeting comprised a combined session for all delegates, and separate breakout sessions for arthroplasty and fracture-related infection. Consensus questions for each session were prepared in advance by the UK PJI working group, based upon topics that were proposed at previous UK PJI Meetings, and delegates participated in an anonymized electronic voting process. We present the findings of the combined and arthroplasty sessions of the meeting in this article, and each consensus topic is discussed in relation to the contemporary literature.

Inadvertent intraoperative hypothermia during general anesthesia: current state of the problem (literature review)

Inadvertent intraoperative hypothermia is an extremely common complication of the perioperative period, which is the cause of a variety of negative effects. This may be an effect on the hemostatic system, immunity, metabolism of drugs, the occurrence of postoperative chills, which leads to a prolongation of the terms and a decrease in the quality of treatment. We analyzed publications in the databases MedLine, PubMed, Google Scholar, Web of Science, Scopus for the period 2008–2023, which contained information on the physiology of the thermoregulatory system, its functioning under general anesthesia, as well as the effect of inadvertent intraoperative hypothermia on various functional systems. We reviewed meta-analyses, systematic reviews, clinical guidelines, observational studies, and case series supplemented by a review of the literature lists in relevant publications. We demonstrated the physiology of thermoregulation system, as well as changes in its functioning under general anesthesia. We shown the impact of inadvertent intraoperative hypothermia on various functional systems. We demonstrated methods of prevention that minimize the risk of inadvertent intraoperative hypothermia.

Strategies to prevent surgical site infections in acute-care hospitals: 2022 Update

The intent of this document is to highlight practical recommendations in a concise format designed to assist acute-care hospitals in implementing and prioritizing their surgical-site infection (SSI) prevention efforts. This document updates the Strategies to Prevent Surgical Site Infections in Acute Care Hospitals published in 2014. This expert guidance document is sponsored by the Society for Healthcare Epidemiology of America (SHEA). It is the product of a collaborative effort led by SHEA, the Infectious Diseases Society of America (IDSA), the Association for Professionals in Infection Control and Epidemiology (APIC), the American Hospital Association (AHA), and The Joint Commission, with major contributions from representatives of a number of organizations and societies with content expertise.

Late summer is a risk factor for periprosthetic joint infection after total joint arthroplasty: A retrospective cohort study

To explore whether season is a risk factor of periprosthetic joint infection (PJI) after total joint arthroplasty (TJA) and explain it with the theory of traditional Chinese medicine. This was a retrospective cohort study. Only patients who suffered from PJI within 1 month after TJA were included in the study. Occurrence of PJI was the outcome of this study. Chi-squared test and t test was used to assess differences for baseline characteristics. Chi-square test was used to analyze whether season was related to the occurrence of PJI. Logistic regression was used to evaluate the association between season and occurrence of PJI. The incidence of PJI in summer is significantly higher than that in winter, whether after total knee arthroplasty (Chi-square value = 6.455, P = .011) or total hip arthroplasty (Chi-square value = 6.141, P = .013). Summer was an independent risk factor for PJI (OR = 4.373, 95% confidence interval = 1.899-10.673, P = .004). To be more exact, compared to nonlate summer (19.51%), and PJI is mainly concentrated in late summer (80.49%). Late summer was an independent risk factor of PJI after TJA. The infection rate of PJI after TJA in late summer is higher than other seasons. A more thorough preoperative disinfection procedure is needed in late summer.

Incidence of Severe Hypothermia and Its Impact on Postoperative Surgical Complications and Time Delay to Adjunct Treatments in Breast Surgery Cancer Patients: A Case-Controlled Study

Introduction: Unintended postoperative hypothermia frequently occurs upon arrival in the post anesthesia care unit (PACU). As part of our quality assurance program in anesthesia, we regularly monitor the incidence of this complication through our anesthesia information management system (AIMS). In this case-controlled retrospective study, our goal was to detect the incidence of unintended severe hypothermia in our breast surgery cancer patients, and subsequently to analyze the consequence of this complication in terms postoperative cutaneous infection, as well as its impact on further complementary treatment, such as radiotherapy and chemotherapy. Methods: This study was a retrospective analysis conducted through our AIMS system from 2015 through 2019, with extraction criteria based on year, type of surgery (breast), and temperature upon arrival in PACU. A tympanic temperature of less than 36 °C was considered to indicate hypothermia. Severe hypothermia was considered for patients having a temperature lower than 35.2 °C (hypothermic) (n = 80), who were paired using a propensity score analysis with a control group (normothermic) (n = 80) of other breast cancer surgery patients. Extracted data included time of surgery, sex, age, ASA status, and type and duration of the intervention. Results: The mean incidence of hypothermia was 21% from 2015 through 2019. The body mass index (BMI) was significantly lower in the hypothermia group before matching, 23.5 ± 4.1 vs. 26.4 ± 6.1 kg/m² in normothermic patients (p < 0.05). The hypothermia group also had significantly fewer monitoring and active warming devices. No difference was noted for wound complications. Time to complementary chemotherapy and or radiotherapy did not differ between groups (52 ± 21 days in group hypothermia vs 49 ± 22 days in the control group). Conclusion: Severe intraoperative hypothermia remains an important quality assurance issue in our breast surgery cancer patients, but we could not detect any long-term effect of hypothermia.

Short-Periods of Pre-Warming in Laparoscopic Surgery. A Non-Randomized Clinical Trial Evaluating Current Clinical Practice

Background: Pre-warming prevents perioperative hypothermia. We evaluated the current clinical practice of pre-warming and its effects on temperature drop and postoperative complications; Methods: This prospective, observational pilot study examines clinical practice in a tertiary hospital on 99 patients undergoing laparoscopic urological surgery. Pre-warming was performed in the pre-anesthesia room. Patients were classified into three groups: P 0 (non-prewarmed), P 5–15 (pre-warming 5–15 min) and P > 15 (pre-warming 15–30 min). Tympanic temperature was recorded in the pre-anesthesia room, prior to anesthesia induction, and in the PACU. Esophageal temperature was recorded intraoperatively. The occurrence of shivering, pain intensity, length of stay in PACU, and postoperative complications during hospital stay were also recorded; Results: After pre-warming, between-group difference in body temperature was higher in P > 15 than in P 0 (0.4 °C, 95% CI 0.14–0.69, p = 0.004). Between P 5–15 and P 0 difference was 0.2 °C (95% CI 0.04–0.55, p = 0.093). Temperature at the end of surgery was higher in pre-warmed groups [mean between-group difference 0.5 °C (95% CI 0.13–0.81, p = 0.007) for P 5–15; 0.9 °C (95% CI 0.55–1.19, p < 0.001) for P > 15]. Pain and shivering was less common in pre-warmed groups. Postoperative transfusions and surgical site infections were lower in P > 15; Conclusion: Short-term pre-warming prior to laparoscopic urological surgery decreased temperature perioperative drop and postoperative complications.

Effects of a preoperative forced-air warming system for patients undergoing video-assisted thoracic surgery: A randomized controlled trial

BACKGROUND

The incidence of intraoperative hypothermia is still high despite the proposal of different preventive measures during thoracoscopic surgery. This randomized control study evaluated the effects of 30-minute prewarming combined with a forced-air warming system during surgery to prevent intraoperative hypothermia in patients undergoing video-assisted thoracic surgery under general anesthesia combined with erector spinae nerve block.

METHODS

Ninety-eight patients were randomly and equally allocated to prewarming or warming groups (n = 49 each). The primary outcome was the incidence of intraoperative hypothermia. Secondary outcomes were core temperature, irrigation and infused fluid, estimated blood loss, urine output, type of surgery, intraoperative anesthetic dosage, hemodynamics, recovery time, the incidence of postoperative shivering, thermal comfort, postoperative sufentanil consumption and pain intensity, patient satisfaction, and adverse events.

RESULTS

The incidence of intraoperative hypothermia was significantly lower in the prewarming group than the warming group (12.24% vs 32.65%, P = .015). Core temperature showed the highest decrease 30 minutes after surgery start in both groups; however, the rate was lower in the prewarming than in the warming group (0.31 ± 0.04°C vs 0.42 ± 0.06°C, P < .05). Compared with the warming group, higher core temperatures were recorded for patients in the prewarming group from T1 to T6 (P < .05). Significantly fewer patients with mild hypothermia were in the prewarming group (5 vs 13, P = .037) and recovery time was significantly reduced in the prewarming group (P < .05). Although the incidence of postoperative shivering was lower in the prewarming group, it was not statistically significant (6.12% vs 18.37%, P = .064). Likewise, the shivering severity was similar for both groups. Thermal comfort was significantly increased in the prewarming group, although patient satisfaction was comparable between the 2 groups (P > .05). No adverse events occurred associated with the forced-air warming system. Both groups shared similar baseline demographics, type of surgery, total irrigation fluid, total infused fluid, estimated blood loss, urine output, intraoperative anesthetic dosage, hemodynamics, duration of anesthesia and operation time, postoperative sufentanil consumption, and pain intensity.

CONCLUSION

In patients undergoing video-assisted thoracic surgery, prewarming for 30 minutes before the induction of anesthesia combined with a forced-air warming system may improve perioperative core temperature and the thermal comfort, although the incidence of postoperative shivering and severity did not improve.

Intraoperative thermal insulation in off-pump coronary artery bypass grafting surgery: a prospective, double blind, randomized controlled, single-center study

Background

About 50% patients who underwent off-pump coronary artery bypass grafting (OPCAB) experienced perioperative hypothermia. Pre-warming and intraoperative infusion of amino acid injection are the most popular perioperative insulation measures in recent years, but neither of them can completely prevent intraoperative hypothermia. The objective is to investigate the effect of preoperative warming and/or intraoperative infusion of amino acid injection on body temperature in patients undergoing OPCAB.

Methods

A prospective, double blind, randomized controlled, single-center study. Seventy-two patients were randomly divided into 4 groups: control group, pre-warming group, amino-acid group and multi-mode group. Pre-warming and multi-mode group were pre-heated with warming blankets and forced-air warming system before induction. After that, amino-acid and multi-mode group were infused with 18-amino acid solution. The perioperative temperature and complications were monitored.

Results

The temperature of control and amino-acid group decreased significantly, but amino-acid group recovered to preoperative level faster. The temperature of pre-warming group was stable, and that in multi-mode group increased at 60 min after the start of surgery. There was a significant difference in temperature at each time, and no difference in the incidence of complications between the groups.

Conclusions

Preoperative warming and/or intraoperative infusion of amino acid injection can effectively reduce hypothermia in OPCAB surgery. Pre-warming before anesthesia is more effective, and the combination of the two methods has the best effect.