Forced-air Warming Research Articles

Forced-air prewarming prevents hypothermia during living donor liver transplantation: a randomized controlled trial

Despite various intraoperative thermal strategies, core heat loss is considerable during liver transplantation and hypothermia is common. We tested whether forced-air prewarming prevents hypothermia during liver transplantation. Adult patients undergoing living donor liver transplantation were randomly assigned to non-prewarming group (n = 20) or prewarming group (n = 20). Patients in prewarming group underwent 30-min forced-air warming before anesthetic induction. During surgery, core temperature was measured in the pulmonary artery. The primary outcome was intraoperative hypothermia (< 36.0 °C). The secondary outcomes included plasma lactate concentration. Intraoperative hypothermia risk was significantly lower in prewarming group than in non-prewarming group (60.0% vs. 95.0%, P = 0.020). The difference in hypothermia incidence between groups was greater in the post-induction phase (20.0% vs. 85.0%, P < 0.001) than in the anhepatic or post-reperfusion phase, suggesting that prewarming mainly acts on preventing post-induction core-to-peripheral heat redistribution. Hypothermia duration was significantly shorter in prewarming group (60 [0–221] min vs. 383 [108–426] min, P = 0.001). Lactate concentration decreased during 3 h after graft reperfusion in prewarming group, whereas it continuously increased in non-prewarming group (− 0.19 [− 0.48 to 0.13] mmol/L vs. 1.17 [3.31–0.77] mmol/L, P = 0.034). In conclusion, forced-air prewarming decreases the incidence and duration of intraoperative hypothermia with potential clinical benefit while mainly acting by preventing the core-to-peripheral heat redistribution.Clinical trial registration: Registered at the Clinical Research Information Service (https://cris.nih.go.kr, [KCT0003230]) on 01/10/2018.

Effect of forced-air warming blankets on indoor air quality in unidirectional flow operating theatres

Perioperative hypothermia increases the likelihood that a patient will get a surgical site infection, which is one of the biggest public health problems. Controversy exists regarding the effect of forced-air warming systems on the disruption of unidirectional discharge of ultra-clean air in operating theaters. However, researchers agree that thermal blankets are indeed useful to prevent hypothermia. This work aims to analyze the effect of a forced-air warming blanket on the indoor air quality in the surgical field of a high-performance operating theater as a function of the supply velocity employing Computational Fluid Dynamics. An operating theater, its facilities, medical staff, and patient covered with a drape were modeled. Ten cases with driving speeds between 0.20 and 0.40 m/s at 0.05 m/s intervals, with thermal blankets ON and OFF, were simulated. Both air renewal and particle dispersion results in the breathing zone were analyzed. The results show that the use of thermal blankets to avoid patient hypothermia is acceptable at discharge velocities of 0.30 m/s because both the decontamination kinetics and air renewal are improved by 45.6% and 37.6%, respectively. Unfavorable results were obtained for the rest of the case studies with different supply velocities.

Incidence of postoperative hypothermia and shivering and risk factors in patients undergoing malignant tumor surgery: a retrospective study

BackgroundPerioperative hypothermia and shivering are common and can cause adverse outcomes. The aim of this study was to investigate the incidence of postoperative hypothermia and shivering and their risk factors in patients undergoing malignant tumor surgery.MethodsThis retrospective study collected data from patients with American Society of Anesthesiologists physical status (ASA) I or II who underwent scheduled surgery from November 2020 to March 2021 at Fudan University Shanghai Cancer Center. Each patient’s core body temperature was measured at three time points: time point 1 (arrival at the postanesthesia care unit (PACU)), time point 2 (after 30-min care in the PACU), and time point 3 (at discharge from the PACU). At time point 1, if the patient’s body temperature was below 36 ℃, we provided an active forced-air warmer. At time point 2, if it was still below 36 ℃, the forced-air warmer was still applied until the patient was discharged from the PACU. If it reached 36 ℃, the forced-air warmer would be switched off. Univariate and multivariate logistic regression combined with stepwise methods and linear regression were used to explore risk factors for postoperative hypothermia and shivering.ResultsThe numbers (percentage) of 202 patients who developed postoperative hypothermia at the different time points were 52 (25.7%), 37 (18.3%) and 28 (13.9%). Eight patients (4.0%) experienced shivering. Multivariate logistic regression showed that high weight (OR = 0.923, 95% CI: 0.884 to 0.964, P = 0.0003) and low estimated blood loss (OR = 0.252, 95% CI: 0.115 to 0.550, P = 0.0005) were protective factors against hypothermia, while long surgical duration (OR = 3.339, 95% CI: 1.675 to 6.655, P = 0.0006) was an independent risk factor for hypothermia at time point 1. There was no risk factor associated with the occurrence of shivering (P > 0.05). There was a significant difference between the hypothermia and normothermia groups in the median length of stay in the PACU (59.0 vs. 49.0 min, P = 0.0123).ConclusionsPostoperative hypothermia occurred frequently. Weight, estimated blood loss and surgical duration were significantly associated with hypothermia on arrival at the PACU.

Effect of Short Duration Used of Active Prewarming for Preventing Hypothermia in Non-Anesthetized Volunteer: A Randomized-Controlled Trial

Background: Prewarming with a forced-air warmer device at least 30 minutes before entering the operating room (OR) helps to prevent inadvertent perioperative hypothermia (IPH), although doing so on a regular schedule may be difficult. Prewarming for a short time may reduce IPH and is more practical. Objective: To investigate the incidence of hypothermia in non-anesthetized volunteers who used a forced-air warmer device for 10 minutes before entering the OR. Materials and Methods: The present study was a prospective, randomized-controlled trial that included 32 non-anesthetized volunteers. Sixteen volunteers were randomly assigned to receive prewarming using a forced-air warmer set at 38℃ for 10 minutes as the PW group and 16 other volunteers did not receive prewarming as the NW group, before entering a 20℃ OR for an hour. The primary outcome was the incidence of hypothermia in the OR. The secondary outcomes were a change in body temperature in the OR, thermal comfort, the requirement for an additional forced-air warmer device, and complications such as skin rash and burn. Results: The incidence of hypothermia in the OR was 25% in the PW group and 18.75% in the NW group, with no statistically significant differences (p&gt;0.999). There were no significant differences in body temperature between groups. In the waiting room, about 50% of the PW group and none of the NW group reported feeling hot discomfort (p=0.002). However, there were no significant differences in thermal comfort when entering the OR and PACU. No participant asked for an additional forced-air warmer device, and there were no observable device-related complications. Conclusion: A short-term use of active prewarming cannot reduce the incidence of hypothermia in non-anesthetized volunteers. Keywords: Short duration; Active prewarming; Hypothermia

A Nomogram for Predicting Unplanned Intraoperative Hypothermia in Patients With Colorectal Cancer Undergoing Laparoscopic Colorectal Procedures.

Unplanned intraoperative hypothermia is a complication that can lead to a variety of negative outcomes, such as cardiovascular events. We aimed to develop and validate an intraoperative hypothermia risk prediction nomogram for patients with colorectal cancer undergoing laparoscopic colorectal procedures. We conducted a prospective cohort study with 1,091 patients (ie, 765 in the training cohort, 326 in the validation cohort) from October 2020 to November 2021. We included six predictors in the nomogram model: body mass index, diabetes diagnosis, ambient temperature, ambient humidity, duration of surgery, and use of a forced-air warmer. The model performed well, and the area under the curve was 0.855. These results, together with an external validation value, mean that health care professionals can use the nomogram to calculate the intraoperative hypothermia risk for patients undergoing laparoscopic colorectal procedures and make clinical decisions based on the results.

Health Technology Assessment for the Prevention of Peri-Operative Hypothermia: Evaluation of the Correct Use of Forced-Air Warming Systems in an Italian Hospital.

This study investigates the implications of using a system for the maintenance of normothermia in the treatment of patients undergoing surgery, determining whether the FAW (Forced-Air Warming) systems are more effective and efficient than the non-application of appropriate protocols (No Technology). We conducted Health Technology Assessment (HTA) analysis, using both real-world data and the data derived from literature, assuming the point of view of a medium-large hospital. The literature demonstrated that Inadvertent Perioperative Hypothermia (IPH) determines adverse events, such as surgical site infection (FAW: 3% vs. No Technology: 12%), cardiac events (FAW: 3.5% vs. No Technology: 7.6%) or the need for blood transfusions (FAW: 6.2% vs. No Technology: 7.4%). The correct use of FAW allows a medium saving of 16% per patient to be achieved, compared to the non-use of devices. The Cost Effectiveness Value (CEV) is lower in the hypothesis of FAW: it enables a higher efficacy level with a contextual optimization of patients' path costs. The social cost is reduced by around 30% and the overall hospital days are reduced by between 15% and 26%. The qualitative analyses confirmed the results. In conclusion, the evidence-based information underlines the advantages of the proper use of FAW systems in the prevention of accidental peri-operative hypothermia for patients undergoing surgery.

Comparative Efficacy of Six Active Warming Systems for Intraoperative Warming in Adult Patients Undergoing Laparoscopic Surgery: A Systematic Review and Network Meta-Analysis.

Intraoperative hypothermia is very common and harmful in adult patients undergoing laparoscopic surgery. A variety of active warming systems has received close attention and has been researched by related scholars. However, the relative efficacy of these systems and which active warming system is preferred for such patients remain unclear. The aim of this study was to compare and rank six active warming systems regarding intraoperative warming efficacy in adult patients undergoing laparoscopic surgery. Following the PRISMA 2020 guidelines, relevant randomized controlled trials (RCTs) on the efficacy of different active warming systems in warming adult patients undergoing laparoscopic surgery were searched from five English databases and three Chinese databases. The quality of the studies was assessed using the Cochrane Risk of Bias tool (RoB2). The outcome was the final intraoperative core temperature. We estimated direct effects by using pairwise meta-analysis, estimated relative effects and ranking with the consistency model to conduct an NetworkMeta-Analysis (NMA). We used GRADE (Grading of Recommendations Assessment, Development, and Evaluation) to assess the certainty of the evidence. Sensitivity analysis was performed to test the robustness of the results. This study is registered with PROSPERO, with number CRD42022309057. In total, 19 RCTs involving 6 active warming systems and comprising 1364 patients were included in this NMA. The NMA once again confirmed the validity of forced-air warming (FAW) systems compared with other active warming systems, and further showed that underbody FAW was associated with more remarkable warming efficacy in different types of FAW systems. NMA was used to perform an exhaustive comparison of the warming efficacy of six active warming systems and indicated that underbody FAW was most likely to be the most effective warming system in adult patients undergoing laparoscopic surgery; however, considering the sparsity of the network, our results should be cautiously interpreted. Furthermore, a large number of high-quality RCTs comparing the warming efficacy of different competitive active warming systems are needed.

Modeling iatrogenic intraoperative hyperthermia from external warming in children: A pooled analysis from two prospective observational studies.

Maintenance of normothermia is an important quality metric in pediatric anesthesia. While inadvertent hypothermia is effectively prevented by forced-air warming, this therapeutic approach can lead to iatrogenic hyperthermia in young children. To estimate the influence of external warming by forced air on the development of intraoperative hyperthermia in anesthetized children aged 6 years or younger. We pooled data from two previous clinical studies. Primary outcome was the course of core temperature over time analyzed by a quadratic regression model. Secondary outcomes were the incidence of hyperthermia (body core temperature >38°C), the probability of hyperthermia over the duration of warming in relation to age and surface-area-to-weight ratio, respectively, analyzed by multiple logistic regression models. The influence of baseline temperature on hyperthermia was estimated using a Cox proportional hazards model. Two hundred children (55 female) with a median age of 2.1 [1st -3rd quartile 1-4.2] years were analyzed. Mean temperature increased by 0.43°C after 1 h, 0.64°C after 2 h, and reached a peak of 0.66°C at 147 min. Overall, 33 children were hyperthermic at at least one measurement point. The odds ratios of hyperthermia were 1.14 (95%-CI: 1.07-1.22) or 1.13 (95%-CI: 1.06-1.21) for every 10 min of warming therapy in a model with age or surface-area-to weight ratio (ceteris paribus), respectively. Odds ratio was 1.33 (95%-CI: 1.07-1.71) for a decrease of 1 year in age and 1.63 (95%-CI: 0.93-2.83) for an increase of 0.01 in the surface-to-weight-area ratio (ceteris paribus). An increase of 0.1°C in baseline temperature increased the hazard of becoming hyperthermic by a factor of 1.33 (95%-CI: 1.23-1.43). In children, external warming by forced-air needs to be closely monitored and adjusted in a timely manner to avoid iatrogenic hyperthermia especially during long procedures, in young age, higher surface-area-to-weight ratio, and higher baseline temperature.

Preoperative Forced-Air Warming Strategy: Is It Effective in Averting Intraoperative Hypothermia in Elderly Trauma Surgical Patients?

Background and objectivesInadvertent perioperative hypothermia is expected in the elderly during central neuraxial anesthesia. We aimed to compare the incidence of intraoperative hypothermia (< 36-degree celsius) between preoperative forced-air warming for 30 minutes and non-warming groups. Also, we compared the time to develop hypothermia, perioperative shivering, duration of intraoperative active warming, metabolic acidosis, surgical site infections, coagulation derangements, and post-anesthesia care unit (PACU) stay.Material and methodologyA total of 100 American Society of Anesthesiologists (ASA) I-III (Age > 60 years) patients scheduled to undergo femur fracture surgeries under central neuraxial anesthesia were enrolled in this single-blinded prospective randomized study. They were randomly allocated into Group A (active forced-air warming for 30 minutes in the preoperative period) and Group B (without forced-air warming). Then, patients were transferred to the operation theatre, where central neuraxial anesthesia was administered for surgery. An infrared tympanic membrane thermometer measured the core body temperature during the different study points.ResultsThe intraoperative hypothermia incidences were 26.0% and 68.0% in groups A and B, respectively. The mean time for developing hypothermia was found to be 143.08 ± 26.26 min and 25.88 ± 9.25 min in groups A and B, respectively. The mean duration of intraoperative active warming was observed to be 15.6 minutes and 103.6 minutes in groups A and B, respectively. The shivering and surgical site infection (SSI) grades were lower in group A.ConclusionA preoperative forced-air warming strategy for 30 minutes helps in reducing the incidence of intraoperative hypothermia and shivering in elderly patients undergoing femur fracture surgeries under central neuraxial anesthesia.

Validation of a Prediction Model for Intraoperative Hypothermia in Patients Receiving General Anesthesia.

Objectives There have been no fully validated tools for the rapid identification of surgical patients at risk of intraoperative hypothermia. The objective of this study was to validate the performance of a previously established prediction model in estimating the risk of intraoperative hypothermia in a prospective cohort. Methods In this observational study, consecutive adults scheduled for elective surgery under general anesthesia were enrolled prospectively at a tertiary hospital between September 4, 2020, and December 28, 2020. An intraoperative hypothermia risk score was calculated by a mobile application of the prediction model. A wireless axillary thermometer was used to continuously measure perioperative core temperature as the reference standard. The discrimination and calibration of the model were assessed, using the area under the receiver operating characteristic curve (AUC), Hosmer–Lemeshow goodness-of-fit test, and Brier score. Results Among 227 participants, 99 (43.6%) developed intraoperative hypothermia, and 10 (4.6%) received intraoperative active warming with forced-air warming. The model had an AUC of 0.700 (95% confidence interval [CI], 0.632–0.768) in the overall cohort with adequate calibration (Hosmer–Lemeshow χ2 = 13.8, P=0.087; Brier score = 0.33 [95% CI, 0.29–0.37]). We categorized the risk scores into low-risk, moderate-risk, and high-risk groups, in which the incidence of intraoperative hypothermia was 23.0% (95% CI, 12.4–33.5), 43.4% (95% CI, 33.7–53.2), and 62.7% (95% CI, 51.5–74.3), respectively (P for trend <0.001). Conclusions The intraoperative hypothermia prediction model demonstrated possibly helpful discrimination and adequate calibration in our prospective validation. These findings suggest that the risk screening model could facilitate future perioperative temperature management.

Comparison of the Effect of Forced-air Warming and Warmed Intravenous Fluid on the Comfort and Prevention of Shivering After Spinal Anesthesia in Patients Undergoing Orthopedic Surgery

PurposeThis study aimed to compare the effect of forced-air warming and warmed intravenous fluid on the comfort and prevention of shivering after spinal anesthesia in patients undergoing orthopaedic surgery. DesignRandomized controlled clinical trial. MethodsA total of 120 patients were randomly divided into three groups: forced-air warming (38°C), warmed intravenous fluid (37°C), and the control group. Patients' comfort and severity of shivering were measured and recorded five times (immediately and 15 minutes after spinal anesthesia, end of the surgery, time of entrance to the recovery room, and 15 minutes after entering the recovery room), and compared with each other. FindingsThere was a significant difference between the three groups in terms of comfort at all points of evaluation times (P < .001). The comfort score in the control group was significantly higher than the two intervention groups (P < .001). Moreover, the comfort score in the warmed intravenous fluid group was significantly higher than the forced-air warming group (P < .001). In addition, there was a significant difference in shivering severity between the three groups at the end of the surgery, entrance to the recovery room, and 15 minutes after surgery (P < .001). The majority of patients in the forced-air warming group (90%) had no shivering at all three times, while the warmed IV fluid and control groups was 65% and 30% respectively. ConclusionsNon-pharmacological methods such as forced-air warming and warmed intravenous fluid can provide comfort and prevent shivering in orthopaedic patients undergoing spinal anesthesia. However, the use of forced-air warming is more effective than warmed intravenous fluid in providing comfort and preventing shivering in these patients. It is recommended that these methods be used in the operating room to provide comfort and prevent shivering in these patients.

Redistributional Hypothermia Prevention by Prewarming with Forced-Air: Exploratory, Open, Randomized, Clinical Trial of Efficacy.

Avoiding redistributional hypothermia that decreases core temperature by 0.5-1.5°C within the 1st hour of surgery is difficult. The efficacy of prewarming using a forced-air warming (FAW) device with a lower-body blanket on redistribution hypothermia during epidural procedures have not been investigated. After ethics approval, 113 patients undergoing laparoscopic surgery under general anesthesia combined with epidural anesthesia were enrolled. Intervention (prewarming) group patients who were warmed from operating room entry, including during epidural anesthesia, was compared with the control group that was warmed from just before surgery started. In total, 104 patients (52, control; 52, prewarming) were analyzed. In the prewarming group, compared to the control group, the core temperature 20 minutes after anesthesia induction (36.9 ± 0.4 vs. 37.1 ± 0.4°C, p < 0.02) was significantly higher. The core temperature was higher in the prewarming group than in the control group until 3 hours after the surgery. In the prewarming group, compared to the control group, the core temperature-time integral below baseline till 180 minutes after surgery start (65.1 ± 64.0 vs. 8.1 ± 18.6°C/min, p < 0.0001) or 30 minutes after anesthesia induction (5.3 ± 6.2 vs. 2.0 ± 4.7°C/min, p < 0.0001) were significantly smaller. Postoperative shivering was comparable between the groups. Prewarming during epidural catheter insertion with a FAW device could safely prevent a core temperature decrease induced by redistribution or heat loss without additional preparation, effort, space, or time requirements.

Combined Forced Air Warming and Warm Intravenous Fluid Strategy for Perioperative Hypothermia in Cesarean Delivery: A Systematic Review and Meta-Analysis

PurposeEvaluate the effect of a combined forced-air warming (FAW) and warm intravenous fluid (IVF) modality on maternal and neonatal outcomes in cesarean delivery under neuraxial anesthesia. DesignSystematic Review and Meta-analysis. MethodsAn extensive search was conducted using PubMed, Cochrane Library, MEDLINE, CINAHL, Google Scholar, and other grey literature. Only randomized controlled trials examining the combined modality on maternal temperatures were included. Risk ratio (RR), mean difference (MD), and standardized mean difference (SMD) were used to estimate outcomes with suitable effect models. Quality of evidence was assessed using the Risk of Bias and GRADE system. FindingsNine trials involving 595 patients were included. Combined strategy showed a smaller change in maternal temperature from baseline by 0.42°C (MD, –0.42; 95% CI, –0.62 to –0.22; P < .0001), higher temperature on PACU arrival (MD, 0.46; 95% CI, 0.11–0.82; P = .01), 15 minutes (MD, 0.43; 95% CI, 0.19–0.67; P = .0004) and 30 minutes after surgery (MD, 0.38; 95% CI, 0.12–0.64; P = .005). Combined strategy also reduced the incidence of hypothermia (RR, 0.55; 95% CI, 0.31–0.95; P = .03), and shivering (RR, 0.40; 95% CI, 0.28–0.58; P < .00001) with improvement in maternal comfort score (SMD; 0.38; 95% CI, 0.08–0.69; P = .01). However, there were no differences in clinical indicators of adverse neonatal outcomes. Lack of participants blinding, and substantial heterogeneity were limitations of this review. ConclusionThe use of combined FAW and warm IVF is an effective strategy in mitigating perioperative hypothermia in cesarean delivery under neuraxial anesthesia.

Fire in the Operating Room: Surgical Case Report From a Forced-Air Warming Device Equipment Fire

Surgical fires are critical life-threatening events that can result in patient morbidity and mortality. This case report describes an equipment fire originating from a forced-air warming device occurring during a shoulder arthroscopy operation and discusses how the surgical team responded to mitigate risks to the patient and staff. Rapid response by the anesthesia professional and the surgical team helped prevent the fire from negatively impacting patient and staff safety. The patient was discharged from the hospital without any complications. We recommend that surgical teams engage in a coordinated and continual cycle of fire prevention, including enhanced education and interprofessional team training.

Prewarming for Prevention of Hypothermia in Older Patients Undergoing Hand Surgery Under Brachial Plexus Block.

BackgroundOlder patients are more vulnerable to inadvertent perioperative hypothermia. Prewarming contributes to the prevention of inadvertent perioperative hypothermia in patients under general or neuraxial anesthesia. However, the effects of brachial plexus block (BPB) on thermoregulation and the efficacy of prewarming in the prevention of hypothermia in older patients undergoing surgery with BPB remain unclear. This study evaluated the effects of BPB on thermoregulation and the efficacy of prewarming during BPB in older patients.MethodsPatients aged ≥65 years were randomly allocated to receive either standard preoperative insulation (control group, n=20) or preanesthetic forced-air warming for 20 minutes before BPB (prewarming group, n=20). During the perioperative period, tympanic temperatures were measured. Thermal comfort scores and shivering grades were also obtained.ResultsThe tympanic temperatures at the end of surgery did not differ between the groups (36.9°C±0.5°C and 37.0°C±0.4°C in the control and prewarming groups, respectively; p=0.252). The maximum temperature change was significantly lower in the prewarming group compared to the control group (0.36°C±0.4°C and 0.65°C±0.3°C, respectively; p=0.013). The hypothermia incidence and severity, thermal comfort scores, and shivering grades did not differ between the groups.ConclusionRegardless of the application of prewarming, BPB did not cause a clinically significant impairment of thermoregulation. Moreover, the efficacy of prewarming appeared to be low; thus, it may not be routinely required in patients undergoing orthopedic hand surgery under BPB.

The effect of warm and humidified gas insufflation in gynecological laparoscopy on maintenance of body temperature: a prospective randomized controlled multi-arm trial

BackgroundHypothermia is defined as a decrease in body core temperature to below 36 °C. If intraoperative heat-preserving measures are omitted, a patient’s temperature will fall by 1 – 2 °C. Even mild forms of intraoperative hypothermia can lead to a marked increase in morbidity and mortality. Using warm and humidified gas insufflation in laparoscopy may help in the maintenance of intraoperative body temperature.MethodsIn this prospective randomized controlled study, we investigated effects of temperature and humidity of the insufflation gas on intra- and postoperative temperature management. 150 patients undergoing gynecologic laparoscopic surgery were randomly assigned to either insufflation with non-warmed, non-humidified CO2 with forced air warming blanket (AIR), humidified warm gas without forced air warming blanket (HUMI) or humidified warm gas combined with forced air warming blanket (HUMI+). We hypothesized that the use of warmed laparoscopic gas would have benefits in the maintenance of body temperature and reduce the occurrence of hypothermia.ResultsThe use of warm and humidified gas insufflation alone led to more hypothermia episodes with longer duration and longer recovery times as well as significantly lower core body temperature compared to the other two groups. In the comparison of the AIR group and HUMI + group, HUMI + patients had a significantly higher body temperature at arrival at the PACU (Post Anaesthesia Care Unit), had the least occurrence of hypothermia and suffered from less shivering.ConclusionThe use of warm and humidified gas insufflation alone does not sufficiently warm the patients. The optimal temperature management is achieved in the combination of external forced air warming and insufflation of warm and humidified laparoscopy gas.

Therapeutic Hyperthermia Is Associated With Improved Survival in Afebrile Critically Ill Patients With Sepsis: A Pilot Randomized Trial.

To test the hypothesis that forced-air warming of critically ill afebrile sepsis patients improves immune function compared to standard temperature management. Single-center, prospective, open-label, randomized controlled trial. One thousand two hundred-bed academic medical center. Eligible patients were mechanically ventilated septic adults with: 1) a diagnosis of sepsis within 48 hours of enrollment; 2) anticipated need for mechanical ventilation of greater than 48 hours; and 3) a maximum temperature less than 38.3°C within the 24 hours prior to enrollment. Primary exclusion criteria included: immunologic diseases, immune-suppressing medications, and any existing condition sensitive to therapeutic hyperthermia (e.g., brain injury). The primary outcome was monocyte human leukocyte antigen (HLA)-DR expression, with secondary outcomes of CD3/CD28-induced interferon gamma (IFN-γ) production, mortality, and 28-day hospital-free days. External warming using a forced-air warming blanket for 48 hours, with a goal temperature 1.5°C above the lowest temperature documented in the previous 24 hours. We enrolled 56 participants in the study. No differences were observed between the groups in HLA-DR expression (692 vs 2,002; p = 0.396) or IFN-γ production (31 vs 69; p = 0.678). Participants allocated to external warming had lower 28-day mortality (18% vs 43%; absolute risk reduction, 25%; 95% CI, 2-48%) and more 28-day hospital-free days (difference, 2.6 d; 95% CI, 0-11.6). Participants randomized to external forced-air warming did not have a difference in HLA-DR expression or IFN-γ production. In this pilot study, however, 28-day mortality was lower in the intervention group. Future research should seek to better elucidate the impact of temperature modulation on immune and nonimmune organ failure pathways in sepsis.

Effect of active forced air warming during the first hour after anesthesia induction and intraoperation avoids hypothermia in elderly patients

BackgroundThe study aimed at exploring an optimal temperature model of forced air warming during the first hour after induction and intraoperation to prevent hyperthermia for elderly patients undergoing laparoscopic abdominal surgery.MethodsThere were 218 patients that were randomly divided into 3 groups warmed with a forced-air warmer during surgery: Group L (intraoperative warming set to 38 °C, n = 63), Group H (intraoperative warming set to 42 °C, n = 65) and Group LH (intraoperative warming set to 42 °C for the first hour then set to 38 °C, n = 65). Core temperature in the preoperative room and PACU was measured by a tympanic membrane thermometer and in the operation room, a nasopharyngeal temperature probe was recorded. The rate of perioperative hypothermia, defined as a reduction in body temperature to < 36 °C was recorded as the primary outcome. Intraoperative anesthetic dosage, recovery time, adverse events, thermal comfort and satisfaction score were measured as secondary outcome.ResultsThe incidence of intraoperative and postoperative hypothermia was significantly lower in Group LH and Group H than Group L (18.75 and 15.62% vs 44.44%, P<0.001; 4.69 and 4.69% vs 20.63%, P<.05). Anesthetic dosage of rocuronium was lower in Group L than other two groups, with the opposite result of recovery time. The number of patients with shivering was higher in Group L but sweating was higher in Group H. Both of the thermal comfort and satisfaction score was highest in Group LH.ConclusionA temperature pattern of forced air warming set at 42 °C during the first hour after anesthesia induction and maintained with 38 °C was a suitable choice for elderly patients undergoing laparoscopic abdominal surgery lasting for more than 120 min.Trial registrationChictr.org.cn ChiCTR-2,100,053,211.

Попередження інтраопераційної ненавмисної гіпотермії у пацієнтів із політравмою

Актуальність. Ненавмисна гіпотермія розвивається спонтанно як наслідок травми, хірургічного втручання та наркозу в результаті порушення відповідності теплопродукції тепловтрат і пригнічення компенсаторної терморегуляційної відповіді. Мета: вивчити ефективність способу корекції інтраопераційної ненавмисної гіпотермії з використанням системи конвекційного обігріву в пацієнтів із політравмою. Матеріали та методи. Обстежено 20 пацієнтів із політравмою, яким проводились ургентні оперативні втручання. Пацієнти були розділені на 2 групи: I — основна група (n = 10), в якій інтраопераційно проводилося активне зігрівання системою конвекційного обігріву WarmAir 135 (CSZ) з використанням ковдр для зігрівання в умовах операційної; II — контрольна група (n = 10) без використання конвекційного зігрівання. Вивчалася температура ядра тіла (Тсо): початково, через 30, 60 хвилин і наприкінці операції. Розраховувалися наступні показники: мінімальна (Тмін.) і максимальна (Тмакс.) температура, середня температура (Тср.), температурний діапазон (Тдіап. = Tмакс. – Тмін.). Результати. У всіх пацієнтів із політравмою та проведенням ургентних хірургічних втручань відзначається розвиток клінічно значущої ненавмисної гіпотермії. На етапі 60 хвилин інтраопераційного періоду Тсо була вірогідно вище в I групі (35,38 ± 0,28 °С) порівняно з пацієнтами II групи (34,70 ± 0,39 °С) (p &lt; 0,05). Виявлено вірогідно вищий рівень середньої Тсо в I групі (35,53 ± 0,66 °С) порівняно з II групою (34,67 ± 1,74 °С) пацієнтів (p &lt; 0,05). Діапазон температур, який являє собою різницю максимальної та мінімальної Тсо, був вірогідно нижче в I групі пацієнтів (1,36 ± 0,74 °С) порівняно з II групою (4,55 ± 1,11 °С) (p &lt; 0,05). Висновки. Використання в комплексі інтенсивної терапії конвекційної системи зігрівання хоча й не дозволяє досягти вихідних значень Тсо, але попереджає прогресування поглиблення гіпотермії, ефективно забезпечуючи підтримку температурного гомеостазу у критичних пацієнтів із політравмою.

Determining the Effectiveness of Forced-Air Warming Blankets in Maintaining Postoperative Body Temperature: A Randomized Controlled Trial

PurposeThe aim of this study is to determine the effectiveness of forced-air warming blankets in normalizing body temperature in the postoperative period. DesignRandomized controlled trial MethodsThe study sample consisted of patients (N = 67) who underwent lung lobectomy in the Thoracic Surgery Service of a university hospital. Forced-air warming blankets were used in the treatment group and 100% cotton blankets were used in the control group. Patients’ body temperatures were monitored using a tympanic thermometer until it reached 37°C. FindingsThe body temperature of the patients in the treatment group reached 37°C in a shorter time than that of the patients in the control group (52.27 ± 29.79 min and 139.0 ± 81.93 min, respectively; P < .001), and that the perception of comfort of the patients in the treatment and control groups increased (P < .001) after warming. ConclusionsWe recommend that forced-air warming blankets are used for patients undergoing lung lobectomy in order to reach normal body temperature in a shorter time.