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.

The effect of forced-air warming blanket position during spinal surgery on patients' intra-operative body temperature.

BACKGROUND: The use of body-warming systems is recommended by international anaesthesia societies for patients undergoing surgery. Limited research is however available on the influence of positioning of forced-air warming blankets for patients undergoing spinal surgery. This study aimed to investigate how patients' intra-operative body temperature was affected by the position of forced-air warming blankets while undergoing spinal surgery on a spinal table. DESIGN: A randomized comparative experimental study was conducted with 60 adult patients undergoing posterior spinal surgery. METHODS: Patients were randomized into full underbody (n = 30) or surgical access (n = 30) forced-air warming blanket groups. Intra-operative body temperature was recorded at regular time intervals. The student's T-test, Chi-square, and MANOVA tests were performed to determine the differences between the two groups. RESULTS: Intraoperative hypothermia was significantly lower in the full underbody group than in the surgical access group (p = 0.020). The change in body temperature differed significantly between the two groups from 15 min until 240 min, with a mean difference of 0.5 °C. CONCLUSION: The full underbody position of the forced-air warming blanket was effective for maintaining normal range core body temperature. The use of full underbody forced-air warming blanket for spinal surgery when patients are positioned on a spinal table in a prone position is recommended.

Effect of a Forced-Air Warming Blanket on Different Parts of the Body on Core Temperature of Patients Undergoing Elective Open Abdominal Surgery: A Randomized Controlled Single-Blind Trial.

PURPOSE: This study aimed to determine the effect of a forced-air warming blanket placed on different body parts on the core temperature of patients undergoing elective open abdominal surgery. DESIGN: Prospective, single-center, randomized, controlled, single-blind trial. METHODS: A total of 537 patients who underwent open abdominal surgery were randomized into groups A, B, and C and provided with different forced-air warming blankets. Group A was given an upper body blanket, group B a lower body blanket, and group C an underbody blanket. The incidence of intraoperative hypothermia, the time maintaining the core temperature over 36 â„ƒ before hypothermia, the duration of hypothermia, the rewarming rate, and relevant complications were compared among three groups. FINDINGS: Intraoperative hypothermia occurred in 51.4% of patients in group B, 37.6% of patients in group A, and 34.1% of patients in group C (P = .002). Maintaining the core temperature above 36 â„ƒ was longer before hypothermia in groups A and C (log-rank P = .006). In groups A and C, the duration of hypothermia was shorter, the rewarming rate was higher, and the incidence of shivering and postoperative nausea and vomiting were lower, compared to group B. CONCLUSIONS: In patients undergoing elective open abdominal surgery, a forced-air warming blanket on the upper body part or underbody area decreased intraoperative hypothermia, prolonged the time to maintain the core temperature above 36 â„ƒ before hypothermia, and could better prevent further hypothermia when the core temperature had decreased below 36 â„ƒ. In addition, it was significantly superior in reducing shivering and postoperative nausea and vomiting in the postanesthesia care unit.

Effects of different thermal insulation methods on the nasopharyngeal temperature in patients undergoing laparoscopic hysterectomy: a prospective randomized controlled trial.

BACKGROUND: This study explored the comparison of the thermal insulation effect of incubator to infusion thermometer in laparoscopic hysterectomy. METHODS: We assigned 75 patients enrolled in the study randomly to three groups: Group A: Used warming blanket; group B: Used warming blanket and infusion thermometer; group C: Used warming blanket and incubator. The nasopharyngeal temperature at different time points during the operation served as the primary outcome. RESULTS: The nasopharyngeal temperature of the infusion heating group was significantly higher than that of the incubator group 60 min from the beginning of surgery (T3): 36.10 ± 0.20 vs 35.81 ± 0.20 (P<0.001)90 min from the beginning of surgery (T4): 36.35 ± 0.20 vs 35.85 ± 0.17 (P<0.001). Besides, the nasopharyngeal temperature of the incubator group was significantly higher compared to that of the control group 60 min from the beginning of surgery (T3): 35.81 ± 0.20 vs 35.62 ± 0.18 (P<0.001); 90 min from the beginning of surgery (T4): 35.85 ± 0.17 vs 35.60 ± 0.17 (P<0.001). Regarding the wake-up time, that of the control group was significantly higher compared to the infusion heating group: 24 ± 4 vs 21 ± 4 (P = 0.004) and the incubator group: 24 ± 4 vs 22 ± 4 (P = 0.035). CONCLUSION: Warming blanket (38 °C) combined infusion thermometer (37 °C) provides better perioperative thermal insulation. Hospitals without an infusion thermometer can opt for an incubator as a substitute. TRIAL REGISTRATION: This trial was registered with ChiCTR2000039162 , 20 October 2020.

Effect of Forced-Air Warming Blanket on Perioperative Hypothermia in Elderly Patients Undergoing Laparoscopic Radical Resection of Colorectal Cancer.

The study aimed to evaluate the effect of forced-air warming blanket combined with conventional thermal insulation measures on inadvertent perioperative hypothermia (IPH) in elderly patients undergoing laparoscopic radical resection of colorectal cancer. A total of 70 elderly patients undergoing laparoscopic radical resection of colorectal cancer with general anesthesia were included, and divided into conventional warming treatment (CT) group or forced-air warming treatment (FT) group. In the FT group, based on the conventional warming strategy, patients received prewarming with the forced-air warming blanket (38°C) for ≥20 minutes before induction of anesthesia, and received this treatment continuously during operation. The core body temperature, recovery time from anesthesia, extubating time, and length of stay in the postanesthesia care unit were recorded. The incidence of IPH and postoperative shivering was observed. The incidence of IPH was significantly lower, and average minimum body temperature during the operation was significantly higher in the FT group than that in the CT group (5.7% vs. 22.8% and 36.23°C vs. 35.89°C, respectively). The intraoperative body temperature decreased less (0.32°C vs. 0.69°C), the recovery time from anesthesia was faster (12.8 minutes vs. 17.1 minutes), and the incidence of postoperative shivering was less (2.8% vs. 28.6%) in the FT group than the CT group. In elderly patients undergoing laparoscopic radical resection of colorectal cancer, use of forced-air warming blankets combined with conventional warming measures is more effective to maintain normal body temperature during the perioperative period and reduce the incidence of IPH.

Sources of contamination in the operating room: A fluorescent particle powder study.

This study utilized fluorescent particle powder to investigate 2 potential sources of sterile field contamination in the operating room (OR): forced-air warming blankets and OR light manipulation. In part 1, sterile draping for knee replacement surgery was performed on a mannequin in a sterile OR, comparing field contamination with the forced-air warming on versus off during draping. In part 2, OR lights coated with fluorescent powder were manipulated over a sterile field. Proper operation of these devices may reduce the particle burden on the surgical field.

An Unusual Cause of Electrocardiographic Artefact: A Patient's Warming Blanket.

In electrocardiography, an electrocardiographic (ECG) artefact is used to indicate a misleading or confusing alteration in data or observation not arising from the heart. Although technological advancements have produced monitors that may provide accurate data and reliable heart rate alarms, interferences of the displayed electrocardiogram such as (but not limited to) electrical interference by outside sources, electrical noise from elsewhere in the body, poor contact and machine malfunction continue to occur. Artefacts are extremely common, and knowledge regarding them is necessary to prevent misinterpretation of a heart's rhythm, which can often lead to unnecessary and unwarranted diagnostic and interventional procedures. Here we report a case of ECG artefacts that occur owing to a patient's warming blanket and its consequences.

Active perioperative patient warming using a self-warming blanket (BARRIER EasyWarm) is superior to passive thermal insulation: a multinational, multicenter, randomized trial.

STUDY OBJECTIVE: Incidence of inadvertent perioperative hypothermia is still high; therefore, present guidelines advocate "prewarming" for its prevention. Prewarming means preoperative patient skin warming, which minimizes redistribution hypothermia caused by induction of anesthesia. In this study, we compared the new self-warming BARRIER EasyWarm blanket with passive thermal insulation regarding mean perioperative patient core body temperature. DESIGN: Multinational, multicenter randomized prospective open-label controlled trial. SETTING: Surgical ward, operation room, postanesthesia care unit at 4 European hospitals. PATIENTS: A total of 246 adult patients, American Society of Anesthesiologists class I to III undergoing elective orthopedic; gynecologic; or ear, nose, and throat surgery scheduled for 30 to 120 minutes under general anesthesia. INTERVENTIONS: Patients received warmed hospital cotton blankets (passive thermal insulation, control group) or BARRIER EasyWarm blanket at least 30 minutes before induction of general anesthesia and throughout the perioperative period (intervention group). MEASUREMENTS: The primary efficacy outcome was the perioperative mean core body temperature measured by a tympanic infrared thermometer. Secondary outcomes were hypothermia incidence, change in core body temperature, length of stay in postanesthesia care unit, thermal comfort, patient satisfaction, ease of use, and adverse events related to the BARRIER EasyWarm blanket. MAIN RESULTS: The BARRIER EasyWarm blanket significantly improved perioperative core body temperature compared with standard hospital blankets (36.5°C, SD 0.4°C, vs 36.3, SD 0.3°C; P<.001). Intraoperatively, in the intervention group, hypothermia incidence was 38% compared with 60% in the control group (P=.001). Postoperatively, the figures were 24% vs 49%, respectively (P=.001). Patients in the intervention group had significantly higher thermal comfort scores, preoperatively and postoperatively. No serious adverse effects were observed in either group. CONCLUSIONS: Perioperative use of the new self-warming blanket improves mean perioperative core body temperature, reduces the incidence of inadvertent perioperative hypothermia, and improves patients' thermal comfort during elective adult surgery.

Clinical considerations in the use of forced-air warming blankets during orthognathic surgery to avoid postanesthetic shivering.

BACKGROUND: During head and neck surgery including orthognathic surgery, mild intraoperative hypothermia occurs frequently. Hypothermia is associated with postanesthetic shivering, which may increase the risk of other postoperative complications. To improve intraoperative thermoregulation, devices such as forced-air warming blankets can be applied. This study aimed to evaluate the effect of supplemental forced-air warming blankets in preventing postanesthetic shivering. METHODS: This retrospective study included 113 patients who underwent orthognathic surgery between March and September 2015. According to the active warming method utilized during surgery, patients were divided into two groups: Group W (n = 55), circulating-water mattress; and Group F (n = 58), circulating-water mattress and forced-air warming blanket. Surgical notes and anesthesia and recovery room records were evaluated. RESULTS: Initial axillary temperatures did not significantly differ between groups (Group W = 35.9 ± 0.7℃, Group F = 35.8 ± 0.6℃). However, at the end of surgery, the temperatures in Group W were significantly lower than those in Group F (35.2 ± 0.5℃ and 36.2 ± 0.5℃, respectively, P = 0.04). The average body temperatures in Groups W and F were, respectively, 35.9 ± 0.5℃ and 36.2 ± 0.5℃ (P = 0.0001). In Group W, 24 patients (43.6%) experienced postanesthetic shivering, while in Group F, only 12 (20.7%) patients required treatment for postanesthetic shivering (P = 0.009, odds ratio = 0.333, 95% confidence interval: 0.147-0.772). CONCLUSIONS: Additional use of forced-air warming blankets in orthognathic surgery was superior in maintaining normothermia and reduced the incidence of postanesthetic shivering.

Effect of Self-warming Blankets on Intravascular Hypothermia for Severe Traumatic Brain Injury / 中国康复理论与实践

Objective:To investigate the effect of constant temperature blankets on intravascular hypothermia for severe traumatic brain injury (sTBI). Methods:A total of 112 inpatients with sTBI from January, 2013 to December, 2018 were reviewed. They were divided into control group (n = 58) and observation group (n = 54) according to whether a self-warming blanket was used. They were assessed with Bedside Shivering Assessment Scale (BSAS). Their dosages of anti-shivering medicine, coagulation and intracranial pressure were recorded. The scores of Glasgow Outcome Scale Extended (GOSE) and the mortality one, six and twelve months after discharge were observed. Results:The incidence and severity were less in the observation group than in the control group (χ2 = 16.212, P < 0.01). The dosage of anti-shivering medicine was less in the observation group than in the control group (t > 1.269, P < 0.05). The hypercoagulation relieved significantly six hours after hypothermia in the observation group, and it was stable twelve hours after hypothermia. For the control group, the hypercoagulation relieved significantly twelve hours after hypothermia, and it was stable 24 hours after hypothermia. The intracranial pressure decreased more in the observation group than in the control group. The GOSE score and the mortality were less in the observation group than in the control group (t > 1.168, P < 0.05) one, six and twelve months after discharge. Conclusion:Application of self-warming blankets in intravascular hypothermia for sTBI may relieve shivering, hypercoagulation and intracranial pressure, to improve the outcome of patients.

Clinical considerations in the use of forced-air warming blankets during orthognathic surgery to avoid postanesthetic shivering

BACKGROUND: During head and neck surgery including orthognathic surgery, mild intraoperative hypothermia occurs frequently. Hypothermia is associated with postanesthetic shivering, which may increase the risk of other postoperative complications. To improve intraoperative thermoregulation, devices such as forced-air warming blankets can be applied. This study aimed to evaluate the effect of supplemental forced-air warming blankets in preventing postanesthetic shivering. METHODS: This retrospective study included 113 patients who underwent orthognathic surgery between March and September 2015. According to the active warming method utilized during surgery, patients were divided into two groups: Group W (n = 55), circulating-water mattress; and Group F (n = 58), circulating-water mattress and forced-air warming blanket. Surgical notes and anesthesia and recovery room records were evaluated. RESULTS: Initial axillary temperatures did not significantly differ between groups (Group W = 35.9 ± 0.7℃, Group F = 35.8 ± 0.6℃). However, at the end of surgery, the temperatures in Group W were significantly lower than those in Group F (35.2 ± 0.5℃ and 36.2 ± 0.5℃, respectively, P = 0.04). The average body temperatures in Groups W and F were, respectively, 35.9 ± 0.5℃ and 36.2 ± 0.5℃ (P = 0.0001). In Group W, 24 patients (43.6%) experienced postanesthetic shivering, while in Group F, only 12 (20.7%) patients required treatment for postanesthetic shivering (P = 0.009, odds ratio = 0.333, 95% confidence interval: 0.147-0.772). CONCLUSIONS: Additional use of forced-air warming blankets in orthognathic surgery was superior in maintaining normothermia and reduced the incidence of postanesthetic shivering.

The Effects of Blanket Application on Reducing Cold Discomfort after Cesarean Section / 기본간호학회지

PURPOSE: This study was to examine the changes in cold discomfort according to the type of blanket used after surgery. Methods: Women scheduled for Cesarean Section were divided into two groups. After the surgery, 30 patients were covered with a warming blanket which was set at 40degree C by the warmer and the other 30 patients were covered with an ordinary blanket. Both group's cold discomfort was measured at 5 time points using a mercury thermometer, shivering scale, and subjective thermal sensation scale. Data were analyzed by using mean scores with t-test, paired t-test using the SPSS/WIN program. RESULT: At 30 min after being covered with the blanket, the axillary temperature had returned to the pre-operation temperature in both groups. At 45 min after being covered with the blanket, the women in the warming blanket group had no further shivering but for those in the ordinary blanket group shivering continued. At 45 min after being covered with the blanket, the women in the warming blanket group had returned to the condition before surgery. but those in the ordinary blanket group continued to complain of cold sensation. CONCLUSION: This study suggests that use of a warming blanket helps to relieve cold discomfort following surgery. This study is also expected to enhance understanding of the importance of subjective data by exploring the difference between subjective complaints and objective data about cold discomfort.