Intraoperative Temperature Monitoring Research Articles

AB097. SOH24AB_039. Intra-operative temperature monitoring: an audit of compliance to the national standard at University Hospital Limerick

AB097. SOH24AB_039. Intra-operative temperature monitoring: an audit of compliance to the national standard at University Hospital Limerick

Spatiotemporal estimations of temperature rise during electroporation treatments using a deep neural network

The nonthermal mechanism for irreversible electroporation has been paramount for treating tumors and cardiac tissue in anatomically sensitive areas, where there is concern about damage to nearby bowels, ducts, blood vessels, or nerves. However, Joule heating still occurs as a secondary effect of applying current through a resistive tissue and must be minimized to maintain the benefits of electroporation at high voltages. Numerous thermal mitigation protocols have been proposed to minimize temperature rise, but intraoperative temperature monitoring is still needed. We show that an accurate and robust temperature prediction AI model can be developed using estimated tissue properties (bulk and dynamic conductivity), known geometric properties (probe spacing), and easily measurable treatment parameters (applied voltage, current, and pulse number). We develop the 2-layer neural network on realistic 2D finite element model simulations with conditions encompassing most electroporation applications. Calculating feature contributions, we found that temperature prediction is mostly dependent on current and pulse number and show that the model remains accurate when incorrect tissue properties are intentionally used as input parameters. Lastly, we show that the model can predict temperature rise within ex vivo perfused porcine livers, with error <0.5 °C. This model, using easily acquired parameters, is shown to predict temperature rise in over 1000 unique test conditions with <1 °C error and no observable outliers. We believe the use of simple, readily available input parameters would allow this model to be incorporated in many already available electroporation systems for real-time temperature estimations.

Using a Normothermia Bundle With Perioperative Prewarming to Reduce Patient Hypothermia

PurposeTo determine if implementing a normothermia bundle, which includes preoperative forced-air warming blankets, reduces incidence of inadvertent perioperative hypothermia (IPH). DesignIntervention study using retrospective chart review. MethodsPatients received a preoperative forced-air warming blanket and temperature management with the normothermia bundle. Temperature status data was collected from patient charts to evaluate the incidences of IPH and findings from this data analysis was used to measure improvement in perioperative temperature management. FindingsOf 200 patients, 63 (31.5%) remained normothermic, 37 (18.5%) had at least one documented hypothermic temperature, and 100 (50%) had no documented temperature during the intraoperative phase of care. Although compliance with intraoperative temperature monitoring decreased by 13% postintervention, the incidence of documented IPH in reviewed records was decreased by 3.6-fold. ConclusionImplementing a normothermia bundle that includes a preoperative forced-air warming blanket may lower the incidences of IPH, especially in surgical cases lasting over 120 minutes.

Intraoperative Temperature Monitoring with Zero Heat Flux Technology (3M SpotOn Sensor) in Comparison with Tympanic and Oesophageal Temperature and Hypotermia Risk Factors: An Observational Study.

ObjectiveInadvertent hypothermia (body temperature below 35°C) is a common and avoidable challenge during surgery under anaesthesia. It is related to coagulation (clotting) disorders, an increase in blood loss, and a higher rate of wound infection. One of the methods for non-invasive monitoring of the core body temperature is the 3M SpotOn zero heat flux method. In this approach, sensors placed at the frontal region of the patient measure the skin temperature by creating an isothermic channel. The study aimed to determine the risk factors for hypothermia and compare the 3M SpotOn zero heat flux method with the tympanic membrane (eardrum) and oesophageal (food pipe) temperature measurement methods.DesignObservational.Data sourcesThe patients’ data were collected, including age, gender, weight, BMI, other illnesses, smoking history, type of anaesthesia, duration of surgery, operating room temperature, pulse rate, blood pressure, blood loss, and transfusions. Body temperature was measured by the tympanic membrane method before and after surgery, oesophageal method during surgery, and SpotOn measurements throughout all three periods were recorded.Eligibility criteriaInclusion criteria was: adult patients, both genders, who had undergone major abdominal cancer surgery at the trialists’ institution, in whom the SpotOn zero heat flux, tympanic membrane, and oesophageal temperature measurement methods had all been used. Participant exclusion criteria was the absence of recorded data.ResultsIn this study, inadvertent intraoperative hypothermia incidence was 38.1% in the recovery room. Although gender, presence of comorbidities, history of smoking, administration of epidural anaesthesia, and requirement of blood transfusion [red blood cells (RBCs) and fresh frozen plasma (FFP)] did not affect hypothermia significantly during admission to the recovery room, prewarming the patient throughout the operation prevented the occurrence of hypothermia significantly (p=0.004). Additionally, as the American Society of Anaesthesiologists (ASA) physical status score worsened, the rate of hypothermia increased significantly (Frequency: 1st degree, 29.4%; 2nd degree, 47.5%; 3rd degree, 66.7%; X2Slope- p=0.047).ConclusionThe most significant risk factor was found to be not prewarming the patient as a strict procedure, and as the ASA physical status score worsened, the rate of hypothermia increased significantly. Besides, the SpotOn method provided temperature measurements as good as the oesophageal temperature measurements. Clinical Trial registration: ISRCTN 14027708.

Intraoperative zero-heat-flux thermometry overestimates esophageal temperature by 0.26\xa0\xb0C: an observational study in 100 infants and young children

In pediatric anesthesia, deviations from normothermia can lead to many complications, with infants and young children at the highest risk. A measurement method for core temperature must be clinically accurate, precise and should be minimally invasive. Zero-heat-flux (ZHF) temperature measurements have been evaluated in several studies in adults. We assessed the agreement between the 3M Bair Hugger™ temperature measurement sensor (TZHF) and esophageal temperature (TEso) in children up to and including 6 years undergoing surgery with general anesthesia. Data were recorded in 5 min-intervals. We investigated the accuracy of the ZHF sensor overall and in subgroups of different age, ASA classification, and temperature ranges by Bland–Altman comparisons of differences with multiple measurements. Change over time was assessed by a linear mixed model regression. Data were collected in 100 children with a median (1st–3rd quartile) age of 1.7 (1–3.9) years resulting in 1254 data pairs. Compared to TEso (range from 35.3 to 39.3 °C; median 37.2 °C), TZHF resulted in a mean bias of +0.26 °C (95% confidence interval +0.22 to +0.29 °C; 95% limits of agreement −0.11 to +0.62 °C). Lin’s concordance correlation coefficient was 0.89. There was no significant or relevant change of temperature over time (0.006 °C per hour measurement interval, p = 0.199) and no relevant differences in the subgroups. Due to the mean bias of +0.26 °C in TZHF, the risk of hypothermia may be underestimated, while the risk of hyperthermia may be overestimated. Nevertheless, because of its high precision, we consider ZHF valuable for intraoperative temperature monitoring in children and infants.

Perioperative Temperature Management in Children: What Matters?

We carried out a prospective observational study in children undergoing anesthesia in our tertiary pediatric unit. We included 869 patients (<16 y) undergoing emergency/elective surgeries over 2 months. Our team recorded the incidence of hypothermia (tympanic core temperature < 36°C) within 15 minutes of arrival to the postanesthetic care unit. We collected data such as patient demographic, surgical, anesthetic (including monitoring and warming measures used), and operating theater (OT) temperature. We performed statistical analysis to identify risk factors associated with hypothermia. Postoperative hypothermia incidence was 12.3% (107/869). The mean core temperature on arrival to the postanesthetic care unit was 36.6°C (+SD 0.45) in normothermic patients versus 35.6°C (+SD 0.34) in hypothermic patients. Multivariable analysis identified starting ambient OT temperature [odds ratio (OR) = 0.83, confidence interval (CI): 0.71-0.96; P = 0.010], intraoperative temperature monitoring (OR = 0.49, CI: 0.28-085; P = 0.011), use of occlusive dressing (OR = 0.35, CI: 0.15-0.85; P = 0.020), and active forced-air warming (OR = 0.42, CI: 0.25-0.70; P = 0.001) as factors independently protective of postoperative hypothermia. Hypothermia occurred less frequently with emergency vs. elective procedures (OR 0.43, CI: 0.21-0.91; P = 0.026). Routine core temperature monitoring and active forced-air warming are useful measures to prevent hypothermia. Additionally, occlusive covers and controlling ambient OT temperature are cost-effective and safe methods to reduce inadvertent hypothermia.

Enhanced Recovery After Surgery (ERAS) in gynecologic oncology: an international survey of peri-operative practice

IntroductionEnhanced Recovery After Surgery (ERAS) programs have been shown to improve clinical outcomes in gynecologic oncology, with the majority of published reports originating from a small number of specialized centers....

AB243. Key performance indicators in a major teaching hospital anaesthetics department

Background: At present there are no national guidelines on performance measurement for anaesthesia in Ireland. The aim of this study was to determine if we are achieving key performance indicators (KPIs) in areas of intraoperative temperature monitoring, post-operative nausea and vomiting (PONV), and post-operative pain when compared with international literature.

Intra-operative temperature monitoring with two non-invasive devices (3M Spoton® and Dräger Tcore®) in comparison with the Swan-Ganz catheter

BackgroundThe measurement of core body temperature in the pulmonary artery (Swan-Ganz catheter) is regarded as the reference standard. Nowadays, new non-invasive methods of measuring core temperature have emerged, such as the 3M SpotOn® and the Dräger Tcore® sensor. MethodsA cross-sectional descriptive study was conducted on patients undergoing scheduled cardiac surgery. Both devices, and the Swan-Ganz catheter, were simultaneously evaluated. The correlation of temperature values was measured using the intra-class correlation coefficient and Spearman's rank or Pearson correlation analysis. The repeated-measurements version of the Bland and Altman test were used to determine the level of agreement. ResultsA total of 289 measurements were made. Analysis of Spearman rank correlation between the Swan-Ganz catheter and 3M SpotOn® pair yielded a correlation coefficient (r) of 0.82 [95% confidence interval (95% CI); 0.77–0.85, p<0.001], and the result of ICC was 0.88 (95% CI; 0.85–0.90). Bland–Altman analysis showed a bias (SD) of 0.21°C (0.34) [−2.27 to 2.71]. The Swan-Ganz catheter and Dräger Tcore® pair showed r-values of 0.78 (95% CI; 0.73–0.82 and p<0.001), and ICC of 0.78 (95% CI; 0.74–0.82). This pair showed a bias of 0.48°C (0.42) [−2.02–2.98]. ConclusionsBoth the 3M SpotOn® and the Dräger Tcore® provided a high degree of accuracy and precision in measuring the core temperature, and could be used for the control of normothermia in the patient undergoing cardiac surgery.

Perioperative Temperature Measurement Considerations Relevant to Reporting Requirements for National Quality Programs Using Data From Anesthesia Information Management Systems.

Perioperative hypothermia may increase the incidences of wound infection, blood loss, transfusion, and cardiac morbidity. US national quality programs for perioperative normothermia specify the presence of at least 1 "body temperature" ≥35.5°C during the interval from 30 minutes before to 15 minutes after the anesthesia end time. Using data from 4 academic hospitals, we evaluated timing and measurement considerations relevant to the current requirements to guide hospitals wishing to report perioperative temperature measures using electronic data sources. Anesthesia information management system databases from 4 hospitals were queried to obtain intraoperative temperatures and intervals to the anesthesia end time from discontinuation of temperature monitoring, end of surgery, and extubation. Inclusion criteria included age >16 years, use of a tracheal tube or supraglottic airway, and case duration ≥60 minutes. The end-of-case temperature was determined as the maximum intraoperative temperature recorded within 30 minutes before the anesthesia end time (ie, the temperature that would be used for reporting purposes). The fractions of cases with intervals >30 minutes between the last intraoperative temperature and the anesthesia end time were determined. Among the hospitals, averages (binned by quarters) of 34.5% to 59.5% of cases had intraoperative temperature monitoring discontinued >30 minutes before the anesthesia end time. Even if temperature measurement had been continued until extubation, averages of 5.9% to 20.8% of cases would have exceeded the allowed 30-minute window. Averages of 8.9% to 21.3% of cases had end-of-case intraoperative temperatures <35.5°C (ie, a quality measure failure). Because of timing considerations, a substantial fraction of cases would have been ineligible to use the end-of-case intraoperative temperature for national quality program reporting. Thus, retrieval of postanesthesia care unit temperatures would have been necessary. A substantive percentage of cases had end-of-case intraoperative temperatures below the 35.5°C threshold, also requiring postoperative measurement to determine whether the quality measure was satisfied. Institutions considering reporting national quality measures for perioperative normothermia should consider the technical and logistical issues identified to achieve a high level of compliance based on the specified regulatory language.

Intraoperative temperature monitoring with zero heat flux technology (3 M SpotOn sensor) in comparison with sublingual and nasopharyngeal temperature

Intraoperative temperature monitoring with zero heat flux technology (3 M SpotOn sensor) in comparison with sublingual and nasopharyngeal temperature

A rare case of congenital insensitivity to pain with anhydrosiss

Congenital insensitivity to pain syndrome with anhydrosis (CIPA) is a rare inherited disorder. It is characterized by loss of pain and temperature sensation, lack of sweating and mild mental retardation. This disorder belongs to hereditary sensory and autonomic neuropathy family (type IV). Because of these abnormalities, patients require special anesthetic care. They include titration of intraoperative opioids, an anesthetic to ensure co-operation and immobility and intra-operative temperature monitoring. Here we report a 7-year-old female child with CIPA posted for restoration and cementation for dental caries along with sural nerve and skin biopsy.

Long-term oncological follow-up on laparoscopic cryoablation of renal masses with intra-operative temperature monitoring

Long-term oncological follow-up on laparoscopic cryoablation of renal masses with intra-operative temperature monitoring

Survey on intraoperative temperature management in Europe

Inadvertent perioperative hypothermia causes serious morbidity in surgical patients. However, recent reports suggest that patients might still be hypothermic after elective surgery. We thus surveyed intraoperative temperature monitoring and management practices in Europe. Postal survey of 801 representative hospitals from 17 European countries on the same day. The questions addressed the number of surgical procedures and type of anaesthesia performed, mode and site of temperature monitoring and method of patient warming. Mean and standard error of the mean or count and percentage were calculated. The t-test or contingency table analysis with the Fisher's exact test were used. Eight thousand and eighty-three surgical procedures were assessed from 316 responding hospitals (39.4%). Overall, patient temperature monitored in 19.4% and 38.5% of the patients were actively warmed. Under general anaesthesia, body temperature was monitored in 25% and during regional anaesthesia in 6%, P = 0.0005. Nasopharyngeal temperature was most often taken under general anaesthesia, while tympanic temperature was preferred during regional anaesthesia. Under general anaesthesia, 43% of patients were actively warmed as compared to 28% with regional anaesthesia, P = 0.0005. Forced-air warming was the method of choice for both general and regional anaesthesia. Intraoperative temperature monitoring is still uncommon and hence active patient warming is not a standard of care in Europe. Awareness of perioperative hypothermia is critical to its prevention, and thus temperature monitoring is a pre-requisite. The objective is to maintain normothermia in patients throughout surgery. A European practice guideline for perioperative patient temperature management is warranted.

Precision and Accuracy of Intraoperative Temperature Monitoring

Using tympanic membrane (TM) temperature as a standard for core temperature, we quantitated the accuracy and precision of seven other temperature monitoring sites during anesthesia, namely, the nasopharynx, esophagus, rectum, bladder, axilla, forehead, and great toe. Accuracy was quantitated as the difference between TM temperature and the temperature at each of the other sites; precision was quantitated as the correlation between TM temperature and the temperature at each of the other sites. Results indicate that the accuracy of measurements made using the great toe, forehead, and axilla is less than the accuracy of measurements made using the nasopharynx, esophagus, bladder, and rectum. Precision of measurements made using the nasopharynx, esophagus, and bladder is greater than the precision at the axilla, forehead, and rectum, and much higher than the precision at the great toe. Measurements of body temperature using the nasopharynx, esophagus, and bladder are recommended for intraoperative use as providing the best combination of accuracy and precision.

Precision and Accuracy of Intraoperative Temperature Monitoring

Precision and Accuracy of Intraoperative Temperature Monitoring

HYPERTHERMIA DURING ANESTHESIA.

The development of hyperthermia in an anesthetized patient can be a serious threat to the patient's life. Once the temperature rise begins, it proceeds at an ever increasing rate. It may go unrecognized until a sudden deterioration in the patient's condition calls attention to his plight. The physiologic abnormalities associated with the hyperthermia include dehydration, hypotension, hypoxia, and acidosis. Treatment must be prompt if irreversible tissue damage or death are to be avoided, and includes rapid cooling, rehydration, and correction of the electrolyte and acid-base abnormalities. Prevention must include adequate evaluation and treatment of preoperative temperature elevations and hypermetabolic states. Use of intraoperative temperature monitoring would enable the anesthesiologist to recognize and treat the elevated temperature before it climbed seriously high and led to physiological decompensation.