Forced-air Warming Device Research Articles

The Effect of Brief Warming during Induction of General Anesthesia and Warmed Intravenous Fluid on Intraoperative Hypothermia in Patients Undergoing Urologic Surgery.

Background and Objectives: Transurethral urologic surgeries frequently lead to hypothermia due to bladder irrigation. Prewarming in the preoperative holding area can reduce the risk of hypothermia but disrupts surgical workflow, preventing it from being of practical use. This study explored whether early intraoperative warming during induction of anesthesia, known as peri-induction warming, using a forced-air warming device combined with warmed intravenous fluid could prevent intraoperative hypothermia. Materials and Methods: Fifty patients scheduled for transurethral resection of the bladder (TURB) or prostate (TURP) were enrolled and were randomly allocated to either the peri-induction warming or control group. The peri-induction warming group underwent whole-body warming during anesthesia induction using a forced-air warming device and was administered warmed intravenous fluid during surgery. In contrast, the control group was covered with a cotton blanket during anesthesia induction and received room-temperature intravenous fluid during surgery. Core temperature was measured upon entrance to the operating room (T0), immediately after induction of anesthesia (T1), and in 10 min intervals until the end of the operation (Tend). The incidence of intraoperative hypothermia, change in core temperature (T0-Tend), core temperature drop rate (T0-Tend/[duration of anesthesia]), postoperative shivering, and postoperative thermal comfort were assessed. Results: The incidence of intraoperative hypothermia did not differ significantly between the two groups. However, the peri-induction warming group exhibited significantly less change in core temperature (0.61 ± 0.3 °C vs. 0.93 ± 0.4 °C, p = 0.002) and a slower core temperature drop rate (0.009 ± 0.005 °C/min vs. 0.013 ± 0.004 °C/min, p = 0.013) than the control group. The peri-induction warming group also reported higher thermal comfort scores (p = 0.041) and less need for postoperative warming (p = 0.034) compared to the control group. Conclusions: Brief peri-induction warming combined with warmed intravenous fluid was insufficient to prevent intraoperative hypothermia in patients undergoing urologic surgery. However, it improved patient thermal comfort and mitigated the absolute amount and rate of temperature drop.

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.

Perioperative cutaneous complications in an elderly patient due to inappropriate use of a forced-air warming device and underbody blanket: a case report

Forced-air warming is commonly utilized to prevent perioperative hypothermia. Underbody warming blankets are often employed to secure a larger area for patient warming. While forced-air warming systems are generally regarded as safe, improper usage poses a risk of cutaneous complications. Additionally, the influence of underbody blankets on cutaneous complications remains uncertain. We present a case of cutaneous complications resulting from the improper utilization of a forced-air warming device and an underbody blanket. A 79-year-old man presented to the hospital for robotic proctectomy under general anesthesia. The surgery lasted for 7 hours, and the forced-air warming device with underbody blanket operated continuously for 5 hours intraoperatively. The surgery was completed without any incidents. However, first-degree burns on the patient’s back, along with superficial decubitus ulcers on his right scapula, were observed after surgery. To prevent cutaneous complications, clinicians must adhere to the manufacturer's guidelines when utilizing a forced-air warming system. Compared to overbody blankets, underbody blankets have limitations in monitoring cutaneous responses. Ensuring patient safety requires selecting an appropriate blanket for scheduled operations.

Are Intra-operative Forced Air Warming Devices a Possible Source for Contamination During Hand Surgery?

Background Forced air warming (FAW) devices are routinely utilized in operating rooms for patient temperature control. However, there have been some controversy and conflicting evidence on whether they are a possible source of surgical site infections (SSIs) and contamination. Methods A total of 144 petri dishes were randomized to either a control or experimental group (72 in each group). Each trial consisted of six petri dishes in three locations (floor, table, and operative limb). Two dishes at each location were closed sequentially at one hour, two hours, and three hours. Two control and two experimental trials were performed in two separate operating suites with two different FAW devices. The petri dishes were then analyzed for growth for 48 hours. Two culture swabs from each FAW device hose were obtained and analyzed. Results None of the culture swabs analyzed showed any growth on blood or chocolate agar culture media. There was no significant difference in bacterial colony-forming units per cubic meter(CFU/m3) air between the trial and control groups in each location at one hour of exposure. At two hours of exposure, there was a significantly higher bacterial CFU/m3air in the experimental group in the operative limb. At three hours of exposure, there was a significantly higher bacterial CFU/m3airin the experimental group on the floor. However, overall, there was no difference in bacterial CFU/m3 air in both study groups at different times of exposure, incubation, or location. Conclusion Our study was unable to identify any statistically significant risk of contamination associated with the use of FAW devices. However, our study design was limited due to the absence of operating room staff during testing. For this reason, we recommend further research into this topic with the use of an active operating room, which includes simulated movement from the surgeon, anesthesia, scrub technician, nursing, and any other operating room staff who may be present during a real operation.

SP9.8 An Audit of Intraoperative Hypothermia Rates in Adults Undergoing Emergency Surgery in a Tertiary General Surgical Unit and Evaluation of the Efficacy of Preoperative and Intraoperative Forced-Air Warming on Achieving Intraoperative Normothermia

Abstract Aims Surgical site infections (SSIs) inflict significant economic burden on the NHS. Preoperative and intraoperative hypothermia are risk factors for SSIs. Evidence shows that maintenance of intraoperative normothermia significantly reduces SSI rates. Perioperative SSI bundles addressing factors including hair removal, antibiotic prophylaxis, skin preparation, drape positioning, and hypothermia are critical to improving SSI rates. We aim to audit rates of intraoperative hypothermia in our surgical caseload and evaluate the efficacy of preoperative and intraoperative forced-air warming through bespoke gowns in achieving intraoperative normothermia. Methods We conducted a retrospective audit of the intraoperative core temperatures of all adult patients undergoing surgical procedures on the emergency theatre list of a general surgery department and who had a temperature at knife-to-skin recorded (n=88). We then ran a prospective trial, outfitting patients listed for surgery (n=15) with forced-air warming gowns. Patients underwent forced-air warming with the gowns for 45 minutes on the surgical ward, throughout anaesthetic induction, and intraoperatively. Patient core temperature was measured at baseline, upon arrival at the anaesthetic room, and at knife-to-skin. Results Baseline audit data showed over 18% of patients were hypothermic at knife-to-skin. Contrastingly, 100% of patients wearing forced-air warming gowns were normothermic at knife-to-skin. The mean core temperature at knife-to-skin was significantly higher in patients wearing warming gowns (p=0.012). Conclusions Forced-air warming gowns are superior to traditional hospital gowns, blankets and surgical access forced-air warming devices in achieving intraoperative normothermia. They are an effective, sustainable, and cost-neutral, ‘all-in-one’ alternative to current perioperative protocol and will reduce SSI rates.

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.

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.

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.

Effects of a Heated Anesthesia Breathing Circuit on Body Temperature in Anesthetized Rhesus Macaques (Macaca mulatta).

This study evaluated the effects of using a heated anesthesia breathing circuit in addition to forced-air warming on body temperature in anesthetized rhesus macaques as compared with forced-air warming alone. Hypothermia is a common perianesthetic and intraoperative complication that can increase the risk of negative outcomes. Body heat is lost through 4 mechanisms during anesthesia: radiation, conduction, convection, and evaporation. Typical warming methods such as forced-air warming devices, conductive heating pads, and heated surgical tables only influence radiative and conductive mechanisms of heat loss. A commercially available heated breathing circuit that delivers gas warmed to 104 °F can easily be integrated into an anesthesia machine. We hypothesized that heating the inspired anesthetic gas to address the evaporative mechanism of heat loss would result in higher body temperature during anesthesia in rhesus macaques. Body temperatures were measured at 5-min intervals in a group of 10 adult male rhesus macaques during 2 anesthetic events: one with a heated anesthesia breathing circuit in addition to forced-air warming, and one with forced-air warming alone. The addition of a heated breathing circuit had a significant positive effect on perianesthetic body temperature, with a faster return to baseline temperature, earlier nadir of initial drop in body temperature, and higher body temperatures during a 2-h anesthetic procedure. Use of a heated anesthesia breathing circuit should be considered as a significant refinement to thermal support during macaque anesthesia, especially for procedures lasting longer than one hour.

Effect of active warming during general anaesthesia on post-operative body temperature, shivering, thermal comfort, pain, nausea and vomiting in adult patients: a randomized clinical trials protocol

&lt;p&gt;&lt;strong&gt;Background: &lt;/strong&gt;This study aims to investigate the effects of individual and combined use of intraoperative forced-air warming and warmed intravenous and irrigation fluids on post-operative body temperature, shivering, thermal comfort, pain, nausea and vomiting in adult patients receiving general anaesthesia.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods: &lt;/strong&gt;This is a randomised controlled clinical trial. A 2x2 factorial design will used in the experiment. Eligible patients will be randomly assigned to one of four groups. We attempt to report this randomized controlled trial to comply with the spirit. The study population will consist of 120 adult patients receiving general anaesthesia at university hospitals in Turkey. After the induction of anaesthesia, the first group (n=30) will be warmed with only forced-air warming device, the second group (n=30) will receive only warmed intravenous and irrigation fluids, forced-air warming as well as warmed intravenous (IV) and irrigation fluids will be applied to the third group (n=30), the fourth group (n=30) will consist of the control group without any intervention. Blood and blood products to be applied intraoperatively to all groups will be heated to 37°C.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt; The primary outcome measures are post-operative body temperature, shivering, thermal comfort, pain, nausea and vomiting. The primary results will be subjected to a one-way analysis of variance for covariant such as amount of bleeding and volume of intraoperative fluids.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Trial registration: &lt;/strong&gt;The trial has been registered in clinical trials: https://clinicaltrials.gov/. Registration number: NCT04907617).&lt;/p&gt;

A STUDY OF WARMING DEVICES AND PERIOPERATIVE FACTORS POTENTIALLY CONTRIBUTING TO SURGICAL FIELD CONTAMINATION IN SMALL ANIMAL PATIENTS

Bacterial contamination on surgical drapes may increase the risk of surgical site infection (SSI). This preliminary investigation analyzed the relationship between forced-air warming devices and bacterial contamination on surgical drapes in small animal soft tissue surgery settings. The subjects of this study were canine and feline patients enrolled in clean surgical procedures at the National Taiwan University Veterinary Hospital. Bacterial colonies on surgical drapes were sampled on agar plates immediately prior to and 1[Formula: see text]h after skin incision. Cases with bacteria growth on the post-incision sampled agar were considered with surgical field contamination (SFC). Intraoperative warming methods (forced-air warming systems or circulating water blankets) and other factors that potentially contribute to SFC (drape material, patient features, surgical procedure types, surgeons, and number of operating room personnel) were recorded. The study comprised 57 operations, 28 cases belonged to the circulating water blanket group and 29 belonged to the forced-air warming system group. No differences in contamination rate were detected among intraoperative warming methods, drape materials, patient characteristics, surgical procedure types, or number of operating room personnel. However, a significant difference in contamination rate was detected among surgeons.

Efficacy of an Infrared Radiator for Hypothermia Prevention in a Simulated Setup of Entrapped Vehicle Accident Victims

BackgroundProlonged extrication of entrapped patients after road traffic accidents increases the risk of sustained hypothermia. Accident-related hypothermia increases mortality in severely injured patients, and prehospital efforts to prevent hypothermia are essential. We evaluated various warming measures regarding their preclinical suitability and efficacy for patient warming, tested in realistically-simulated road traffic accident scenarios under cold ambient conditions in a climate chamber. MethodsThe effects of a chemical warming blanket (CWB), forced-air warming (FAW) device, or infrared radiator (IRR) on the core body and skin surface temperature of a subject previously exposed to a cold environment (5°C for 12 minutes) was recorded via temperature sensors and thermographically, respectively. Physiological parameters such as oxygen saturation, blood pressure, and heart rate were also monitored. ResultsUnder cold environmental conditions, all devices were able to compensate or overcompensate the cooling of body parts directly exposed to the heating measure. In the body areas that were not directly warmed (back, lower extremities), only the CWB limited further cooling. FAW and IR irradiation rapidly and effectively warmed the heat-exposed areas (head and arms). However, both methods – but especially the IRR – led to a noticeably accelerated cooling in body parts not directly exposed to heat (back, legs). ConclusionThe increased mortality associated with hypothermia in severely injured crash victims during prolonged vehicle extrication has intensified efforts to prevent sustained hypothermia. The use of a CWB, FAW or IRR are in principle all suitable for reducing or compensating for heat loss. The ongoing cooling of those body parts not directly exposed to the heat source was interpreted as a steal phenomenon in regional blood flow. However, the practicality and effectiveness of these measures, combined with their logistical requirements, must be evaluated in real extrication scenarios.

Thermal Burn Injury from a Forced-Air Warming Device in an Anesthetized Dog with Peripheral Hypoperfusion

Thermal Burn Injury from a Forced-Air Warming Device in an Anesthetized Dog with Peripheral Hypoperfusion

Effect of temperature maintenance by forced-air warming blankets of different temperatures on changes in inflammatory factors in children undergoing congenital hip dislocation surgery.

BackgroundHypothermia is associated with many adverse clinical outcomes in pediatric patients, and thus, it is important to find an effective and safe method for preventing peri-operative hypothermia and its associated adverse outcomes in pediatric patients. This study aimed to investigate the effect of forced-air warming blankets with different temperatures on changes in the transforming growth factor-β (TGF-β), tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-10 levels in children undergoing surgical treatment for developmental displacement of the hip (DDH).MethodsThe study included 123 children undergoing surgery for DDH under general anesthesia. The patients were randomly assigned to three groups, using a random number table: the 32, 38, and 43°C groups according to the temperature setting of the forced-air warming blankets. For each patient, body temperature was recorded immediately after anesthesia induction and intubation (T0), at initial incision (T1), at 1 h after incision (T2), at 2 h after incision (T3), at the end of surgery (T4), immediately upon return to the ward after surgery (T5), and then at 12 h (T6), 24 h (T7), 36 h (T8), and 48 h (T9) after the surgery. The serum levels of TGF-β, TNF-α, IL-1β, and IL-10 were measured at T0 and T4 for all groups.ResultsThe number of patients with fever in the 38°C group was significantly less than those in the 32 and 43°C groups (χ2 = 6.630, P = 0.036). At T0, the body temperatures in the 38 and 43°C groups were significantly higher than that in the 32°C group (F = 17.992, P < 0.001). At T2, the body temperature was significantly higher in the 43°C group than those in the 32 and 38°C groups (F = 12.776, P < 0.001). Moreover, at T4, the serum levels of TGF-β (F = 3286.548, P < 0.001) and IL-10 (F = 4628.983, P < 0.001) were significantly increased in the 38°C group, and the serum levels of TNF-α (F = 911.415, P < 0.001) and IL-1β (F = 322.191, P < 0.001) were significantly decreased in the 38°C group, compared with the levels in the 32 and 43°C groups.ConclusionForce-air warming blankets set at 38°C maintained stable body temperature with less adverse outcome and effectively inhibited the inflammatory response in pediatric patients undergoing surgery for DDH.Clinical trial registrationChiCTR1800014820; http://www.chictr.org.cn/showproj.aspx?proj=25240.

Comparison of two forced-air warming devices during foot and ankle surgery: a randomised controlled trial.

Inadvertent perioperative hypothermia is a frequent problem associated with surgical patients which can have significant consequences during surgery and in the immediate postoperative period. We compared 35 randomised patients using over vs. under body forced air heating. There were no statistically significant differences between some demographic and surgical parameters such as: age, weight, height, body mass index, length of anaesthesia and operation. Statistically significant differences were found between the patient's admission to the operating room and 30 minutes and the end of the procedure on the under body patients group. This study analyses a uniform population of patients (Foot and Ankle Surgery) previously not studied and supports the use of under body blankets.

Prevention of Perioperative Hypothermia: A Prospective, Randomized, Controlled Trial of Bair Hugger Versus Inditherm in Patients Undergoing Elective Arthroscopic Shoulder Surgery

To determine if a clinically significant difference in the core body temperature (CBT) exists between the Bair Hugger (BH) and Inditherm (IT) warming devices in patients undergoing arthroscopic shoulder surgery. This was a parallel, 2-treatment, prospective, randomized, controlled trial conducted in patients undergoing elective arthroscopic shoulder surgery in the beach-chair position using room-temperature irrigation fluid. The BH was used as the indicative forced-air warming device, whereas the IT served as the indicative resistive heating system. By use of a minimal clinically significant difference of 0.6°C and standard deviation of 0.6°C, a power analysis showed that a sample size of 90 patients (45 per group) would be required. Patients fulfilling the inclusion criteria were recruited from the clinics of the senior authors. Anesthetic and surgical protocols were standardized. The intraoperative CBT was recorded every 5 minutes using a nasopharyngeal thermistor probe. Demographic data as well as the volume of irrigation fluid used were also noted. A steady decline in the CBT was observed in both groups up to 30 minutes after induction of anesthesia. Beyond 30 minutes, the BH group showed a gradual increase in temperature whereas it continued to decline in the IT group. A statistically significant difference in the CBT was observed from 60 minutes onward (P= .025). This difference continued to increase up to 90 minutes (P < .001). At no time was a rise in the CBT observed in the IT group. At completion of the study and surgical procedure, 13 of 47 patients in the BH group and 32 of 44 patients in the IT group had hypothermia (P= .0002). The CBT was statistically significantly better with the use of the BH compared with the IT mattress. However, the differences in the CBT did not reach the level of clinical significance of 0.6°C. Far fewer patients in the BH group had hypothermia at the end of surgery. Therefore, this study supports the use of the BH in elective arthroscopic shoulder surgery for the prevention of hypothermia. Level I.

Prevalence of hypothermia on admission to recovery room remains high despite a large use of forced-air warming devices: Findings of a non-randomized observational multicenter and pragmatic study on perioperative hypothermia prevalence in France.

BackgroundDespite the availability of effective warming systems, the prevalence of hypothermia remains high in patients undergoing surgery. Occurrence of perioperative hypothermia may influence the rate of postoperative complications. Recommendations for the prevention of inadvertent perioperative hypothermia have been developed and are effective to reduce the frequency of perioperative hypothermia when professionals comply with. French Society of Anesthesiology (SFAR) decided to promote guidelines for the prevention of inadvertent hypothermia, and to conduct beforehand a pragmatic assessment of the prevalence of hypothermia in France. The hypothesis was that the rate of hypothermic patients (Tc<36°C) admitted to the RR remains high (around 50%), and that was the consequence of a warming device underutilization and/or was related to the type of health facilities.MethodsAn observational, prospective and multi-centric study was conducted in France between October 2014 and May 2016 among patients over 45 years undergoing non-cardiac, non-outpatient surgery with anesthesia lasting >30 minutes in 52 centers. Patients undergoing pulmonary or proctologic surgery and those having non-invasive procedures performed under general anesthesia (for example, digestive endoscopy) were excluded from our study. Patients being operated under plexus anesthesia alone, surgeries involving hemorrhaging or infection, and patients presenting at least one organ failure were also excluded. The primary endpoint was the percentage of patients with a core temperature (Tc) <36°C on admission to the recovery room (RR).ResultsAmong 893 subjects (median age 66.9 years), prevalence of hypothermia on admission to the RR was 53.5%. At least one warming system was used for 90.4% of the patients. Identified risk factors for Tc<36°C included age≥70 years (OR = 1.41 [CI95%: 1.02–1.94]), duration of anesthesia from 1 to 2 hours (OR = 1.94 [CI95%: 1.04–3.64]) and a decrease in Tc of >0.5°C between anesthesia induction and surgical incision (OR = 1.82 [CI95%: 1.15–2.89]). Only a combination of pre-warming and intraoperative warming prevented a Tc<36°C (OR = 0.48 [CI95%: 0.24–0.96]).ConclusionsThe prevalence of hypothermia among patients admitted to the RR remains high. Our results suggest that only the combination of pre-warming and intraoperative warming significantly decreases it.

Peri-operative temperature measurement. Guideline or fantasy?

Introduction Perioperative hypothermia is common but associated with adverse outcomes and is defined as patient core temperature below 36.0°C. During the first 30 to 40 minutes of anaesthesia, a patient's temperature can drop to below 35.0°C. National guidelines advise1: • Temperature to be measured and documented in the hour before patient leaves ward • If • Maintain active warming throughout intraoperative phase • Temperature should be 36.0°C before transfer from/to the ward Additionally it is suggested that: - Induction of anaesthesia should not begin unless temperature is 36.0°C - Intravenous fluids (500 ml or more)/blood products should be warmed to 37°C using a fluid warming device - Warm patients intraoperatively from induction of anaesthesia, using a forced-air warming device if they are undergoing anaesthesia for more than 30 minutes, or anaesthesia for less than 30 minutes but are at higher risk of inadvertent perioperative hypothermia. - The patient's temperature should be measured and documented before induction and every 30 minutes until the end of surgery - Temperature should be measured and documented on admission to the recovery room and then every 15 minutes. If the patient's temperature is Methods The electronic charts of 31 patients undergoing routine thoracic surgery of duration over 30 minutes in a dedicated cardiothoracic unit over a two-week period were reviewed. The use of peri-operative temperature measurement was examined. Results 41% of patients had a temperature measured on arrival in the operating department. At 30 minutes into the procedure only 29% had temperature recorded. In the PACU 11 (32%) of patients had temperature measured, and of these only 6 (19%) had an arrival temperate over 36.0oC. Subsequently 1/31 patient had temperature measured every 15 minutes and just 4/31 patients had temperature recorded every 30 minutes. However 42% of patients had temperature recorded at discharge from the PACU. Discussion These data show a small improvement when compared to a previous audit of a similar cohort of patients (38 patients undergoing elective thoracic surgery over 30 minute duration) as shown below: Temperature recorded 2018 2017 Arrival O R 41% 24% 30 min O R 29% 24% Arrival PACU 32% 24% Leave PACU 42% 5% However no single data point exceeded 50% despite efforts to educate operating department staff on the requirement to record temperature and the benefits of actively warming patients.

Forced Air Contamination Risk in the OR

BACKGROUND Patient warming to maintain perioperative normothermia is known to reduce temperature-related complications, improve overall postoperative results and shorten patient hospital stays. Forced-air warming (FAW) devices—commonly used in operating theaters—can introduce bacteria into the surgical environment, increasing both possible contamination and attributable Surgical Site Infection (SSI) risks. A number of published studies point toward a surface-component contamination and tissue-air risk connection. This investigation was designed to seek new data regarding any FAW-bacteria correlation in an effort to both better understand possible, associated, FAW-use risks and contribute to infection-control protocols that more effectively assist in mitigating or diminishing consequential Healthcare Associated Infection (HAI) risk. METHODS A total of 320 surface and air samples were collected and cultured from in and around 35 unique FAW devices actively in-use in operating room (OR) settings at three hospital facilities in an associated acute-care system. Surface samples were taken from multiple FAW device points: the internal hose surface, the proximal hose end and the distal hose end. Each retrieved sample was bagged, plated and incubated under sterile procedures. RESULTS The results show that 24.4 percent (78 of 320) of all samples collected were at higher than maximum acceptable Colony Forming Unit (CFU) pathogens levels. Forty-two and half, 42.5, percent (136 of 320) of all samples were at higher than minimum acceptable CFU levels; 37.2 percent (119 of 320) were equipment samples; 5.3 percent (17 of 320) were air samples. Study results also identified a correlation of positive airborne samples for instances that had high-pathogen contamination in the warmer-temperature components, resulting in a possible increased patient infection risk and possible attributable SSI as primary concerns. CONCLUSIONS FAW device-component contamination may be a risk in the OR. Cross-contamination of the environment remains a risk as well. A reduction in surface and airborne CFUs may positively reduce SSI and HAI infection risk.

What is the predictor of the intraoperative body temperature in abdominal surgery?

Inadvertent hypothermia is a relatively common intraoperative complication. Few studies have investigated predictors of body temperature change or the effect of the blanket type used with a forced-air warming device during the intraoperative period. We investigated the predictive factors of intraoperative body temperature change in scheduled abdominal surgery. We retrospectively reviewed the data from 2574 consecutive adult patients who underwent scheduled abdominal surgery in the supine position. Temperature data were collected from anesthesia records. Multiple regression analysis was performed at 60, 120, and 180min after the surgical incision to identify the factors influencing body temperature change. We conducted nonlinear regression analysis using the equation ΔT = α (e-γt-1)+βt, where ΔT represented the change in intraoperative core temperature (°C), t represented the surgical duration (minutes), and α, β, and γ were constants. The intraoperative core temperature change was explained by the equation ΔT = 0.59 (e- 0.018t-1) + 0.0043t. Younger age, higher body mass index (BMI), male sex, laparoscopic surgery, and use of an underbody blanket were associated with increased core temperature at 1 or 2h after surgical incision. Male sex and an underbody blanket remained strong predictive variables even 3h after surgical incision, whereas BMI had little explanatory power at this timepoint. The difference in the heating effect of an underbody versus an overbody blanket was 0.0012°C per minute. The blanket type of the forced-air warmer, age, sex, laparoscopic surgery, and BMI are predictors of intraoperative core temperature change.