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.

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.

Effect of Prewarming on Perioperative Hypothermia in Patients Undergoing Loco-Regional or General Anesthesia: A Randomized Clinical Trial.

Background and Objectives: Redistribution hypothermia occurs during anesthesia despite active intraoperative warming. Prewarming increases the heat absorption by peripheral tissue, reducing the central to peripheral heat gradient. Therefore, the addition of prewarming may offer a greater preservation of intraoperative normothermia as compared to intraoperative warming only. Materials and Methods: A single-center clinical trial of adults scheduled for non-cardiac surgery. Patients were randomized to receive or not a prewarming period (at least 10 min) with convective air devices. Intraoperative temperature management was identical in both groups and performed according to a local protocol. The primary endpoint was the incidence, the magnitude and the duration of hypothermia (according to surgical time) between anesthetic induction and arrival at the recovery room. Secondary outcomes were core temperature on arrival in operating room, surgical site infections, blood losses, transfusions, patient discomfort (i.e., shivering), reintervention and hospital stay. Results: In total, 197 patients were analyzed: 104 in the control group and 93 in the prewarming group. Core temperature during the intra-operative period was similar between groups (p = 0.45). Median prewarming lasted 27 (17-38) min. Regarding hypothermia, we found no differences in incidence (controls: 33.7%, prewarming: 39.8%; p = 0.37), duration (controls: 41.6% (17.8-78.1), prewarming: 45.2% (20.6-71.1); p = 0.83) and magnitude (controls: 0.19 °C · h-1 (0.09-0.54), prewarming: 0.20 °C · h-1 (0.05-0.70); p = 0.91). Preoperative thermal discomfort was more frequent in the prewarming group (15.1% vs. 0%; p < 0.01). The interruption of intraoperative warming was more common in the prewarming group (16.1% vs. 6.7%; p = 0.03), but no differences were seen in other secondary endpoints. Conclusions: A preoperative prewarming period does not reduce the incidence, duration and magnitude of intraoperative hypothermia. These results should be interpreted considering a strict protocol for perioperative temperature management and the low incidence of hypothermia in controls.

Spatiotemporal Thermal Control Effects on Thermal Grill Illusion.

The thermal grill illusion induces a pain sensation under a spatial display of warmth and coolness of approximately 40 °C; and 20 °C. To realize virtual pain display more universally during the virtual reality experience, we proposed a spatiotemporal control method to realize a variable thermal grill illusion and evaluated the effect of the method. First, we examined whether there was a change in the period until pain occurred due to the spatial temperature distribution of pre-warming and pre-cooling and verified whether the period until pain occurred became shorter as the temperature difference between pre-warming and pre-cooling increased. Next, we examined the effect of the number of grids on the illusion and verified the following facts. In terms of the pain area, the larger the thermal area, the larger the pain area. In terms of the magnitude of the pain, the larger the thermal area, the greater the magnitude of the sensation of pain.

Short interruptions between pre-warming and intraoperative warming are associated with low intraoperative hypothermia rates.

BACKGROUND: Prevention of inadvertent hypothermia is recommended for procedures >30 minutes because hypothermia increases the risk of myocardial ischemia, intraoperative blood loss, transfusion and wound complications. Therefore, short warming interruptions between pre-warming and intraoperative warming might result in lower hypothermia rates. The aim of this retrospective investigation was to determine whether the incidence of inadvertent intraoperative hypothermia was affected by the warming interruption. METHODS: The lowest intraoperative body core temperature value and the warming interruption time were taken from anaesthesia records. Body core temperature was recorded continuously, and a patient was classified to be hypothermic if the lowest recorded temperature value was <36°C. Hypothermia rates and the correlation between warming interruption times and intraoperative hypothermia rates were calculated. RESULTS: Five thousand eighty-four patients were analysed. The intraoperative hypothermia rate was 15.3%. Nineteen patients (0.4%) had a recorded temperature of <35.0°C. An increase in forced-air warming interruption time was significantly associated with an increase in intraoperative hypothermia rates (P < .0001). Patients with interruptions in forced-air warming >20 minutes showed significantly higher hypothermia rates than those with interruptions of ≤20 minutes (P < .0001). CONCLUSION: Intraoperative hypothermia rates increased significantly with longer forced-air warming interruptions between pre-warming and intraoperative warming. Short warming interruptions can preserve the effect of pre-warming and are associated with low intraoperative hypothermia rates.

Efficacy of prewarming prophylaxis method for intraoperative hypothermia during thoracoscopic esophagectomy.

BACKGROUND: This study was performed to elucidate the clinical efficacy of the prewarming prophylaxis method for intraoperative hypothermia during thoracoscopic esophagectomy for esophageal cancer. METHODS: We enrolled 100 consecutive patients with esophageal cancer. Two patients in the prewarming group could not undergo thoracoscopic esophagectomy because of conversion to thoracotomy. The intraoperative core temperature was measured in 50 and 48 patients classified into the control and prewarming groups, respectively. Patients in the prewarming group wore a Bair Hugger warming gown (3 M, Maplewood, MN, USA) in the ward for 30 min before entering the operation room. The primary outcome measure was the difference in the intraoperative body core temperature between the control and prewarming groups, and the secondary outcome measure was the difference in postoperative infectious complications between the control and prewarming groups. RESULTS: The intraoperative core temperature was significantly different between the two groups at each 30-min time point from the starting of operation to the ending of the thoracic procedure (P < 0.001). The incidence of infectious surgical complications was not significantly different between the control and prewarming groups (30.0% vs. 14.6%, respectively; P = 0.11). CONCLUSION: The prewarming prophylaxis method was effective for maintaining normothermia during thoracoscopic esophagectomy.

Impact of brief prewarming on anesthesia-related core-temperature drop, hemodynamics, microperfusion and postoperative ventilation in cytoreductive surgery of ovarian cancer: a randomized trial.

BACKGROUND: General (GA)- and epidural-anesthesia may cause a drop in body-core-temperature (BCTdrop), and hypothermia, which may alter tissue oxygenation (StO2) and microperfusion after cytoreductive surgery for ovarian cancer. Cell metabolism of subcutaneous fat- or skeletal muscle cells, measured in microdialysis, may be affected. We hypothesized that forced-air prewarming during epidural catheter placement and induction of GA maintains normothermia and improves microperfusion. METHODS: After ethics approval 47 women scheduled for cytoreductive surgery were prospectively enrolled. Women in the study group were treated with a prewarming of 43 °C during epidural catheter placement. BCT (Spot on®, 3 M) was measured before (T1), after induction of GA (T2) at 15 min (T3) after start of surgery, and until 2 h after ICU admission (TICU2h). Primary endpoint was BCTdrop between T1 and T2. Microperfusion-, hemodynamic- and clinical outcomes were defined as secondary outcomes. Statistical analysis used the Mann-Whitney-U- and non-parametric-longitudinal tests. RESULTS: BCTdrop was 0.35 °C with prewarming and 0.9 °C without prewarming (p < 0.005) and BCT remained higher over the observation period (ΔT4 = 0.9 °C up to ΔT7 = 0.95 °C, p < 0.001). No significant differences in hemodynamic parameters, transfusion, arterial lactate and dCO2 were measured. In microdialysis the ethanol ratio was temporarily, but not significantly, reduced after prewarming. Lactate, glucose and glycerol after PW tended to be more constant over the entire period. Postoperatively, six women without prewarming, but none after prewarming were mechanical ventilated (p < 0.001). CONCLUSION: Prewarming at 43 °C reduces the BCTdrop and maintains normothermia without impeding the perioperative routine patient flow. Microdialysis indicate better preserved parameters of microperfusion. TRIAL REGISTRATION: ClinicalTrials.gov ; ID: NCT02364219 ; Date of registration: 18-febr-2015.

Influence of oral premedication and prewarming on core temperature of cardiac surgical patients: a prospective, randomized, controlled trial.

BACKGROUND: Perioperative hypothermia is still very common and associated with numerous adverse effects. The effects of benzodiazepines, administered as premedication, on thermoregulation have been studied with conflicting results. We investigated the hypotheses that premedication with flunitrazepam would lower the preoperative core temperature and that prewarming could attenuate this effect. METHODS: After approval by the local research ethics committee 50 adult cardiac surgical patients were included in this prospective, randomized, controlled, single-centre study with two parallel groups in a university hospital setting. Core temperature was measured using a continuous, non-invasive zero-heat flux thermometer from 30 min before administration of the oral premedication until beginning of surgery. An equal number of patients was randomly allocated via a computer-generated list assigning them to either prewarming or control group using the sealed envelope method for blinding. The intervention itself could not be blinded. In the prewarming group patients received active prewarming using an underbody forced-air warming blanket. The data were analysed using Student's t-test, Mann-Whitney U-test and Fisher's exact test. RESULTS: Of the randomized 25 patients per group 24 patients per group could be analysed. Initial core temperature was 36.7 ± 0.2 °C and dropped significantly after oral premedication to 36.5 ± 0.3 °C when the patients were leaving the ward and to 36.4 ± 0.3 °C before induction of anaesthesia. The patients of the prewarming group had a significantly higher core temperature at the beginning of surgery (35.8 ± 0.4 °C vs. 35.5 ± 0.5 °C, p = 0.027), although core temperature at induction of anaesthesia was comparable. Despite prewarming, core temperature did not reach baseline level prior to premedication (36.7 ± 0.2 °C). CONCLUSIONS: Oral premedication with benzodiazepines on the ward lowered core temperature significantly at arrival in the operating room. This drop in core temperature cannot be offset by a short period of active prewarming. TRIAL REGISTRATION: This trial was prospectively registered with the German registry of clinical trials under the trial number DRKS00005790 on 20th February 2014.

Preventing Inadvertent Hypothermia in Patients Undergoing Major Spinal Surgery: A Nonrandomized Controlled Study of Two Different Methods of Preoperative and Intraoperative Warming.

PURPOSE: To evaluate if a Full Access Underbody (FAU) blanket used preoperatively and intraoperatively in patients undergoing major spinal surgery prevents hypothermia compared with current practice and to explore patients' experiences of comfort. DESIGN: A nonrandomized controlled trial. METHODS: Sixty patients were included, 30 in each group. Temperature was assessed on arrival, after connecting to the bladder catheter, and at the start and end of surgery. In the FAU group, comfort was evaluated at arrival and after 10 minutes of prewarming. FINDINGS: The incidence of hypothermia at the start of surgery was significantly lower (relative risk [95% confidence interval], 0.28 [0.13 to 0.59]). Before prewarming, 77% felt comfortable, 20% cold, and 3% hot. After prewarming 60% felt comfortable, 37% hot, and 3% very hot. CONCLUSIONS: Patients using the FAU blanket had a 72% lower incidence of hypothermia at the start of the operation. Attention to thermal comfort during surgery is important.

Effect of pre-warming on perioperative hypothermia during holmium laser enucleation of the prostate under spinal anesthesia: a prospective randomized controlled trial.

BACKGROUND: The purpose of this study is to assess whether the application of preoperative forced air warming set to high temperature (> 43 °C) for brief period can increase temperature on admission to the postanesthesia care unit (PACU) and prevent hypothermia or shivering during holmium laser enucleation of the prostate performed under spinal anesthesia. METHODS: Fifty patients were enrolled were assigned randomly to receive passive insulation (control group, n = 25) or forced-air skin surface warming for 20 min before spinal anesthesia (pre-warming group, n = 25). The primary outcome was temperature at PACU admission. RESULTS: The pre-warming group had a significantly higher temperature on admission to the PACU than the control group (35.9 °C [0.1] vs 35.6 °C [0.1], P = 0.023; 95% confidence interval of mean difference, 0.1 °C-0.5 °C). The trend of decreasing core temperature intraoperatively was not different between groups (P = 0.237), but intraoperative core temperature remained approximately 0.2 °C higher in the pre-warming group (P = 0.005). The incidence of hypothermia on admission to the PACU was significantly lower in the pre-warming group (56% vs 88%, P = 0.025). Shivering occurred in 14 patients in the control group, and 4 patients in the pre-warming group (P = 0.007). CONCLUSION: Brief pre-warming at 45 °C increased perioperative temperature and decreased the incidence of hypothermia and shivering. However, it was not sufficient to modify the decline of intraoperative core temperature or completely prevent hypothermia and shivering. Continuing pre-warming to immediately before induction of spinal anesthesia or combining pre-warming with intraoperative active warming may be necessary to produce clearer thermal benefits in this surgical population. TRIAL REGISTRATION: This trial was registered with Clinicaltrials.gov, NCT03184506 , 5th June 2017.

[Prewarming according to the AWMF S3 guidelines on preventing inadvertant perioperative hypothermia 2014 : Retrospective analysis of 7786 patients]. / Vorwärmung entsprechend der "S3 Leitlinie Vermeidung von unbeabsichtigter perioperativer Hypothermie 2014" : Retrospektive Analyse von 7786 Patienten.

BACKGROUND: Inadvertent perioperative hypothermia, which is defined as a core body temperature of less than 36.0 °C, can have serious consequences in surgery patients. These include cardiac complications, increased blood loss, wound infections and postoperative shivering; therefore, the scientific evidence that inadvertent perioperative hypothermia should be avoided is undisputed and several national guidelines have been published summarizing the scientific evidence and recommending specific procedures. The German AWMF guidelines were the first to emphasize the importance of prewarming for surgery patients to avoid inadvertant perioperative hypothermia; however, in contrast to intraoperative warming, prewarming is so far not sufficiently implemented in clinical practice in many hospitals. Furthermore, a recent study has questioned the effectiveness of prewarming. OBJECTIVE: The aim of this retrospective investigation was to evaluate the hypothermia rates that can be achieved when prewarming in the anesthesia induction room is introduced into the clinical practice and performed in addition to intraoperative warming. MATERIAL AND METHODS: The ethics committee of the Medical Faculty of the Martin Luther University Halle Wittenberg gave approval for data storage and retrospective data analysis from the anesthesia database. According to the existing local standard operating procedure, prewarming with forced air was performed in addition to intraoperative warming in the anesthesia induction room in 3899 patients receiving general anesthesia with a duration of 30 min or longer from January 2015 to December 2016. The results were compared with a control group of 3887 patients from July 2012 to August 2014 who received intraoperative warming but were not subjected to prewarming. Tracheal intubation was carried out in all patients and temperature measurements after the induction of anesthesia were performed using esophageal, urinary catheter or intra-arterial temperature probes. RESULTS: The mean duration of prewarming was 25 min in the treatment group. Patients subjected to prewarming showed an intraoperative hypothermia rate of 15.8% and a postoperative hypothermia rate of 5.1%. Patients without prewarming showed an intraoperative hypothermia rate of 30.4% and a postoperative hypothermia rate of 12.4%. This means a 52% reduction of the intraoperative hypothermia rate and a 41% reduction of the postoperative hypothermia rate for patients who received prewarmimg (p < 0.0001). Multivariate logistic regression revealed that the lack of prewarming was independently associated with intraoperative hypothermia with an odds ratio of 2.5 (95% confidence interval CI 2.250-2.841; p < 0.0001) and postoperative hypothermia with an odds ratio of 2.8 (95% CI 2.316-3.277; p < 0.0001). CONCLUSION: Prewarming, as recommended in the AWMF guidelines, resulted in a significant and clinically relevant reduction in the incidence of inadvertent perioperative hypothermia; therefore, prewarming can still be regarded as an effective method to avoid perioperative hypothermia. Hypothermia rates of 15.8% intraoperatively and 5.1% postoperatively can be achieved in clinical practice, when prewarming is performed in addition to intraoperative warming in the anesthesia induction room directly before the start of surgical procedures.

Reflective Blankets Are as Effective as Forced Air Warmers in Maintaining Patient Normothermia During Hip and Knee Arthroplasty Surgery.

BACKGROUND: The use of forced air warming devices in the operating room has been shown to cause disruption of laminar airflow and a potential for increase in surgical site contamination. In contrast, conductive warming devices such as reflective blankets do not disrupt airflow and therefore have no potential for this increase in surgical site infection. However, some studies have shown them to be inferior to forced air warming devices in maintaining normothermia. We tested the hypothesis that the use of reflective blankets is as effective as forced air warming devices in maintaining intraoperative normothermia after adequate prewarming. METHODS: We performed a randomized, controlled trial of 50 patients undergoing hip or knee arthroplasty using a protocol of prewarming followed by application of either forced air warming device or a reflective blanket and recording the patients sublingual temperature at a 15-minute interval till arrival in the post-anesthesia care unit. RESULTS: There was no significant difference in the sublingual temperatures in the 2 groups at any time point. CONCLUSION: Our study shows that after a period of adequate prewarming, the use of reflective blankets is as effective as the use of forced air warming devices in maintaining normothermia in patients undergoing hip or knee arthroplasty.

The Optimal Time and Method for Surgical Prewarming: A Comprehensive Review of the Literature.

PURPOSE: Inadvertent hypothermia is a common problem in the operating room. This can contribute to many unfavorable outcomes --rising costs, increased complications, and higher morbidity rates. DESIGN: This review determined the optimal method and time to prewarm a surgical patient to prevent perioperative hypothermia. METHODS: CINAHL and PubMed were searched. Fourteen articles were ultimately included in this review. FINDINGS: Based on the literature reviewed, it was suggested that forced-air warming was most effective in preventing perioperative hypothermia. Eighty-one percent of the experimental studies reviewed found that there was a significantly higher temperature throughout surgery and in the postanesthesia care unit for patients who received forced-air prewarming. CONCLUSIONS: Thirty minutes was found to be the average suggested amount of time for prewarming among the literature; however, a minimum of 10 minutes of prewarming was suggested to significantly reduce rates of hypothermia in perioperative patients and decrease the adverse effects of hypothermia.

Efficacy of Prewarming With a Self-Warming Blanket for the Prevention of Unintended Perioperative Hypothermia in Patients Undergoing Hip or Knee Arthroplasty.

PURPOSE: Unintended perioperative hypothermia (UPH) is a common and serious complication for patients undergoing anesthesia. The purpose of this study was to identify the incidence of UPH and evaluate the efficacy of a self-warming blanket on the drop in core temperature and risk of UPH in patients undergoing hip or knee arthroplasty. DESIGN: A case-control study was used. METHODS: Sixty patients were included. Thirty patients received prewarming with a self-warming blanket and forced-air warming intraoperatively; thirty patients received only forced-air warming intraoperatively. FINDING: The incidence of UPH (<36°C) was identified in 13% of the patients in the prewarmed group and 43% of the patients in the control group. Mean core temperature in the prewarmed group was significantly higher and remained above 36°C in the perioperative period. CONCLUSIONS: The study suggests that preoperative warming with a self-warming blanket reduces the incidence of UPH and decreases the drop in core temperature.

"Keeping Them Warm"-A Randomized Controlled Trial of Two Passive Perioperative Warming Methods.

PURPOSE: Inadvertent perioperative hypothermia is a common problem for patients undergoing surgery. Heat redistribution from the body's core to the periphery after induction of anesthesia is the major contributor. DESIGN: A prospective randomized controlled trial was conducted to determine if reflective blankets are more effective than cotton blankets in reducing the core-peripheral temperature gradient and increasing peripheral compartment heat content during the preoperative phase among adult patients undergoing elective surgery of less than 1 hour. About 328 adult patients undergoing general anesthesia were randomly allocated into two groups. METHODS: Data were analyzed using independent t tests for continuous variables and chi-square tests for categorical variables. FINDINGS: There was a significantly smaller reduction in temporal artery/foot temperature gradient (1.13 vs 1.64°C, P < .001) and a significant increase in foot temperature (0.64 vs 0.11°C, P < .001) in the reflective blanket group. CONCLUSIONS: Reflective blankets are more effective than cotton blankets in warming patients' periphery and reducing core-peripheral temperature gradient preoperatively. AUSTRALIAN NEW ZEALAND CLINICAL TRIALS REGISTRY NUMBER: ACTRN12614000931673 (retrospective registration).

[Implementation of a thermal management concept to prevent perioperative hypothermia : Results of a 6­month period in clinical practice]. / Umsetzung eines Wärmemanagementkonzeptes zur Vermeidung von perioperativer Hypothermie : Ergebnisse eines Sechsmonatszeitraums in der klinischen Praxis.

BACKGROUND: Perioperative hypothermia is defined as a core temperature below 36 °C. The literature shows that perioperative hypothermia is a frequent but potentially preventable complication of the surgical process. The risk of experiencing perioperative hypothermia is inherent for all anesthetized patients, independent of the type of surgery. Unless preventative measures are taken, perioperative hypothermia occurs in 50 to 70 % of all surgical patients. In Germany and Austria the guideline "Preventing inadvertent perioperative hypothermia" has been published. In Wolfsburg we started already in 2012 with a standard operating procedure to prevent perioperative hypothermia in all surgical patients. In two clinical departments we established an additional prewarming-protocol starting prior to induction of anaesthesia on the normal ward on the day of surgery. MATERIAL AND METHODS: For a period of 6 months we analyzed all temperature data of patients having undergone surgery, beginning before the start of general anaesthesia until the end of the operation. RESULTS: In total 3228 patients were enrolled into the study. Prewarming was performed in 1329 patients. In 1902 patients active warming was limited to the intraoperative period. The total rate of hypothermia in all patients was 32.6 %, whereas the rate of hypothermia at the end of the operation was 19.3 %. In the group of patients without prewarming the overall rate was 39.1 vs. 25 % at the end of the operation. In the groups of patients with prewarming the total rates of hypothermia were 25.2 and 24.7 % overall and 14.4 and 12.5 % at the end of the operation. In multifactorial regression it could be shown that patients without prewarming had a 1.8-fold increased risk of perioperative hypothermia compared to patients with intraoperative warming only. CONCLUSION: We conclude that temperature management is a challenge in the clinical situation, and that it is difficult to achieve rates of hypothermia close to zero. The addition of prewarming was very effective in improving the results in our patients.

The efficacy of pre-warming on reducing intraprocedural hypothermia in endovascular coiling of cerebral aneurysms.

BACKGROUND: The anesthetic management of patients undergoing endovascular treatment of cerebral aneurysms in the interventional neuroradiology suite can be challenged by hypothermia because of low ambient temperature for operating and maintaining its equipments. We evaluated the efficacy of skin surface warming prior to induction of anesthesia to prevent the decrease in core temperature and reduce the incidence of hypothermia. METHODS: Seventy-two patients were randomized to pre-warmed and control group. The patients in pre-warmed group were warmed 30 minutes before induction with a forced-air warming blanket set at 38°C. Pre-induction tympanic temperature (Tpre) was measured using an infrared tympanic thermometer and core temperature was measured at the esophagus immediately after intubation (T0) and recorded at 20 minutes intervals (T20, T40, T60, T80, T100, and T120). The number of patients who became hypothermic at each time was recorded. RESULTS: Tpre in the control and pre-warmed group were 36.4 ± 0.4°C and 36.6 ± 0.3°C, whereas T0 were 36.5 ± 0.4°C and 36.6 ± 0.2°C. Core temperatures in the pre-warmed group were significantly higher than the control group at T20, T40, T60, T80, T100, and T120 (P < 0.001). Compared to T0, core temperatures at each time were significantly lower in both two groups (P = 0.007 at T20 in pre-warmed group, P < 0.001 at the other times in both groups). The incidence of hypothermia was significantly lower in the pre-warmed group than the control group from T20 to T120 (P = 0.002 at T20, P < 0.001 at the other times). CONCLUSION: Pre-warming for 30 minutes at 38°C did not modify the trends of the temperature decrease seen in the INR suite. It just slightly elevated the beginning post intubation base temperature. The rate of decrease was similar from T20 to T120. However, pre-warming considerably reduced the risk of intraprocedural hypothermia. TRIAL REGISTRATION: Clinical Research Information Service (CRiS) Identifier: KCT0001320. Registered December 19th, 2014.

Prewarming in a pediatric hospital: process improvement through interprofessional collaboration.

A quality improvement project intended to promote maintenance of normothermia through active prewarming was carried out at a pediatric specialty hospital. An alternative active, forced-air warming product (Bair Paws warming gowns) was trialed in place of the existing active warming product (Bair Hugger blankets). Converting to the new product was intended to improve patient and staff compliance with prewarming recommendations. The alternative forced air active warming product was favored by both staff and patients, and the rate of compliance with this practice nearly doubled following the change in product. Extensive interprofessional collaboration and problem solving were required to go from an idea to a fully implemented change. The project demonstrated the importance of collaboration among various disciplines and the positive impact interprofessional collaboration can have on compliance with practice changes.

Clinical Efficacy of 10 Min of Active Prewarming for Preserving Patient Body Temperature during Percutaneous Nephrolithotomy: A Prospective Randomized Controlled Trial.

Background: Percutaneous nephrolithotomy (PNL) poses a risk of hypothermia. Additionally, general anesthesia lowers the thresholds for shivering and vasoconstriction, which leads to dysfunction of central thermoregulation. Perioperative hypothermia is associated with adverse outcomes after surgery. In this study, we aimed to demonstrate that prewarming for 10 min can effectively prevent early hypothermia during PNL. Methods: A total of 68 patients scheduled for elective PNL were recruited to this study from January to June 2022, but two patients were excluded because of a change in the surgical plan. After randomization, patients in the prewarming group (n = 32) received warming using a forced-air warming device for 10 min in the preoperative area before being transferred to the operating room, while the controls (n = 34) did not. The incidence of hypothermia within the first hour after inducing general anesthesia was the primary outcome. Perioperative body temperatures and postoperative recovery findings were also evaluated. Results: Early intraoperative hypothermia decreased significantly more in the prewarming group than in the control group (9.4% vs. 41.2%, p = 0.003). Moreover, the net decrease in core body temperature during surgery was smaller in the prewarming group than in the control group (0.2 °C, vs. 0.5 °C, p = 0.003). In addition, the prewarmed patients had a lower incidence of postoperative shivering and a shorter post-anesthesia-care unit (PACU) stay (12.5% vs. 35.3%, p = 0.031; and 46 vs. 50 min, p = 0.038, respectively). Conclusions: Prewarming for 10 min decreased early hypothermia, preserved intraoperative body temperature, and improved postoperative recovery in the PACU.

Effect of prewarming and continuous warming on tissue dissolving ability of Triton™ versus Twin Kleen™: An in vitro study.

Context: TwinKleen™ and Triton™ are newer all-in-one irrigants that have simultaneous action on both organic and inorganic contents. Studies comparing their tissue dissolving ability (TDA) either at room temperature (RT) or on prewarming (PW) and continuous warming (CW) are not yet reported. Aims: To evaluate and compare the effect of 3% sodium hypochlorite (NaOCl), Twin Kleen™, and Triton™, on the bovine TDA. Materials and Methods: One hundred and twenty tissue specimens (size 4 mm × 4 mm × 2 mm and weight 37 ± 3 mg) were divided into Group 1, normal saline (negative control); Group 2, 3% NaOCl (positive control); Group 3, Twin Kleen™; and Group 4, Triton™ (n = 30) Each group is further divided into three subgroups with ten samples each as sub group a - at room temperature (RT), sub group b - on pre warming (PW) and sub group c- on continuous warming (CW), Tissue specimens were immersed in test tubes with 5 ml of respective irrigants replenished thrice every 15 min. The percentage difference in tissue weights was calculated after 5, 10, and 15 min. Statistical Analysis Used: Multiple intergroup comparisons were done using Tukey's multiple-comparison test, using SPSS software version 23.0. Results: Both Triton™ and 3% NaOCl showed significantly higher dissolution than normal saline and Twin Kleen™ on CW followed by PW than at RT. Twin Kleen™ showed significantly less dissolution at all the tested temperatures. Conclusions: Heating enhances the TDA of Triton™ and 3% NaOCl but not Twin Kleen™. CW showed significantly higher dissolution than PW.