Esophageal Temperature Research Articles

Optimal Positioning of Nasopharyngeal Temperature Probes in Infants and Children: A Prospective Cohort Study.

The nasopharynx is an easily accessible core-temperature monitoring site, but insufficient or excessive nasopharyngeal probe insertion can underestimate core temperature. Our goal was to estimate optimal nasopharyngeal probe insertion depth as a function of age. We enrolled 157 pediatric patients who had noncardiac surgery with endotracheal intubation in 5 groups: (1) newborn to 6 months old, (2) infants 7 months to 1 year old, (3) children 13 to 23 months old, (4) children 2 to 5 years old, and (5) children 6 to 12 years old. A reference esophageal temperature probe was inserted at an appropriate depth based on each patient's height. A nasopharyngeal temperature probe was inserted from the naris at 10 cm in newborn and infants, 15 cm in children aged 1 to 5 years old, and 20 cm in children who were 6 years or older. The study nasopharyngeal probes were withdrawn 1, 2.5, or 2 cm (depending on age) 10 times at 5-minute intervals. Optimal probe insertion distances were defined by limits of agreement (LOAs) between nasopharyngeal and esophageal temperatures <0.5 °C. Optimal nasopharyngeal temperature probe position ranged from 6 to 10 cm in infants up to 6 months old, 7 to 8 cm in infants 7 to 12 months old, 7.5 to 12 cm in children 13 to 23 months old, and 10 to 12 cm in children aged 6 years and older. The 95% LOAs were <0.5 °C for all age categories except the 2- to 5-year-old group where the limits extended from -0.67 °C to 0.52 °C at 9 cm. At the optimal position within each age range, the bias (average nasopharyngeal-to-esophageal temperature difference) was ≤0.1 °C. Nasopharyngeal thermometers accurately measure core temperature, but only when probes are inserted a proper distance, which varies with age. As with much in pediatrics, nasopharyngeal thermometer insertion depths should be age appropriate.

Systemic Prostacyclin Analogues for Frostbite Require Careful Monitoring.

Frostbite interventions are not well studied, but recent evidence suggests combining a prostacyclin analog with hyperbaric oxygen can be beneficial.1 We treated an otherwise healthy 24-year-old, 75-kg female who had been found unresponsive in the snow with significant skin exposure for 2 hours. She had bradycardia to the 30’s (beats per minute), an initial esophageal temperature of 24°C, and suffered significant grade 3 frostbite on her feet and toes. She received standard treatments per hospital protocol including rewarming and bilateral catheter-directed intra-arterial infusions of alteplase 0.5 mg/h and heparin 250 units/h. Both medications were stopped after 4 hours for profound thrombocytopenia (platelets 45 × 103/μL). The thrombocytopenia was associated with a 4 g/dL drop in hemoglobin, although she had no obvious bleeding. Subcutaneous heparin was continued for deep vein thrombosis prophylaxis, but no other anti-coagulant or anti-platelet agents were used during her admission. Epoprostenol, a prostacyclin analogue, was started as an IV infusion at 0.5–2 ng/kg/min for 6 hours on hospital day 2 and repeated daily for 6 days.1 Studies from Europe and Canada suggest prostacyclin analogues, classically used for treating pulmonary arterial hypertension, can reduce amputation rates in cases of severe frostbite, due to vasodilatory effects.2

Esophageal Protection and Temperature Monitoring Using the Circa S-Cath™ Temperature Probe during Epicardial Radiofrequency Ablation of the Pulmonary Veins and Posterior Left Atrium

Although epicardial bipolar radiofrequency ablation should diminish the risk of esophageal thermal injury in comparison to an endocardial ablation, cases of lethal atrio-esophageal fistula have been reported. To better understand this risk and to reduce the possibility of a thermal injury, we monitored the esophageal temperature with the Circa S-Cath™ temperature probe during and immediately after the ablation while implementing three procedural safety measures. Twenty patients (15 males; 63 ± 10 years) were prospectively enrolled (November 2019-February 2021). All patients underwent an epicardial ablation procedure, including an antral left and right pulmonary vein isolation with bidirectional bipolar clamping, and a roof and inferior line using unidirectional bipolar radiofrequency. Three procedural preventive mitigations were implemented: (1) transesophageal echocardiographic visualization of the atrio-esophageal interface, with probe retraction before the energy delivery; (2) lifting the ablated tissue away from the esophagus during an energy application; and (3) a 30 s cool-off and irrigation period after the energy delivery. The esophageal temperature was recorded using an insulated multisensory intraluminal esophageal temperature probe (Circa S-Cath™). Of the 20 patients enrolled, 7 patients had paroxysmal atrial fibrillation (AF), 8 persistent AF and 5 longstanding persistent AF. The average maximum luminal esophageal temperature observed was 36.2 ± 0.7 °C (34.8-38.2 °C). In our clinical experience, no abrupt increase in the luminal esophageal temperature above the baseline was observed. Since no measurements exceeded the threshold of 39 °C, no prompt interruption of energy delivery was required. Intraluminal esophageal temperature monitoring is feasible and can be helpful in confirming correct catheter position and safe energy application in bipolar epicardial left atrial ablation. Intra-procedural preventive mitigations should be implemented to reduce the risk of esophageal temperature rises.

Radiofrequency Pulmonary Vein Isolation without Esophageal Temperature Monitoring: Contact-Force Characteristics and Incidence of Esophageal Thermal Damage

Esophageal thermal lesions following pulmonary vein isolation (PVI) for atrial fibrillation (AF) potentially harbor lethal complications. Radiofrequency (RF)-PVI using contact force-technology can reduce collateral damage. We evaluated the incidence of endoscopically detected esophageal lesions (EDEL) and the contribution of contact force to esophageal lesion formation without esophageal temperature monitoring. One hundred and thirty-one AF patients underwent contact force-guided RF-PVI. Contact force, energy, force-time-integral, and force-power-time-integral were adopted. During PVI at the posterior segment of the wide antral circumferential line, limits were set for energy (30 W), duration (30 s) and contact force (40 g). Ablations were analyzed postero-superior and -inferior around PVs. Endoscopy within 120 h identified EDEL in six patients (4.6%). In EDEL(+), obesity was less frequent (17% vs. 68%, p = 0.018), creatinine was higher (1.55 ± 1.18 vs. 1.07 ± 0.42 mg/dL, p = 0.016), and exclusively at the left postero-inferior site, force-time-integral and force-power-time-integral were greater (2973 ± 3267 vs. 1757 ± 1262 g·s, p = 0.042 and 83,547 ± 105,940 vs. 43,556 ± 35,255 g·J, p = 0.022, respectively) as compared to EDEL(-) patients. No major complications occurred. At 12 months, arrhythmia-free survival was 74%. The incidence of EDEL was low after contact force-guided RF-PVI. Implementing combined contact force-indices on the postero-inferior site of left-sided PVs may reduce EDEL.

Optimal Insertion Depth of Gastric Decompression Tube with a Thermistor for Patients Undergoing Laparoscopic Surgery in Trendelenburg Position.

Monitoring core temperature is crucial for maintaining normothermia during general anesthesia. Insertion of a gastric decompression tube (GDT) may be required during laparoscopic surgery. Recently, a newly designed GDT with a thermistor for monitoring esophageal temperature has been introduced. The purpose of the present study was to evaluate the optimal insertion depth of a GDT with a thermistor. Forty-eight patients undergoing elective laparoscopic surgery in the Trendelenburg position were included in the study. The GDT was inserted to a depth of nose-earlobe-xiphoid distance (NEX) + 12 cm and withdrawn sequentially, 2 cm at a time, at 5-min intervals. Temperatures of the GDT thermistor were compared with the core temperature of the tympanic membrane (TM) using Bland and Altman analysis. The correlation between optimal insertion depth of the GDT and anatomical distance (cricoid cartilage to the carina, CCD; carina to the left hemidiaphragm, CLHD) was evaluated, and a mathematical model to predict the optimal insertion depth of the GDT with a thermistor was calculated. Temperatures of TM and GDT thermistor at NEX + 4 cm showed good agreement and strong correlation, but better agreement and stronger correlation were seen at the actual location with the most minor temperature differences. The optimal insertion depth of the GDT was estimated as -15.524 + 0.414 × CCD - 0.145 × CLHD and showed a strong correlation with the actual GDT insertion depth (correlation coefficient 0.797, adjusted R2 = 0.636). The mathematical formula using CCD and CLHD would be helpful in determining the optimal insertion depth of a GDT with a thermistor.

Abstract 14986: Reduced Arrhythmia Recurrence at One-Year When Using Active Esophageal Cooling

Introduction: The use of active esophageal cooling instead of traditional luminal esophageal temperature (LET) monitoring during left atrial ablation for the treatment of atrial fibrillation (AF) allows contiguous lesion placement with fewer partially-formed lesions and less catheter repositioning than required with LET monitoring. As a consequence, fewer electrical reconnections, and a lower rate of atrial arrhythmia recurrence, may result. We aimed to determine the association between esophageal protective strategy and recurrence of arrhythmia at one-year. Methods: We performed an IRB-approved review of an existing hospital registry to measure the association between recurrence of arrhythmia at one year follow-up and the use of active esophageal cooling as opposed to LET monitoring. Data were collected from ablations performed between 2017 and 2020. For each patient we recorded the type of esophageal temperature management, rhythm status at one-year follow-up, ejection fraction, and CHA 2 DS 2 -VASc score. Results: Data from a total of 247 ablations were collected. There were 95 ablations that occurred in the actively cooled group and 152 in the LET monitored group. Among those in the actively cooled group, the average CHA 2 DS 2 -VASc score was 1.8, and the average ejection fraction was 61%. In the LET monitored group, the average CHA 2 DS 2 -VASc score was 1.2 and the average ejection fraction was 61%. In the LET monitored group, there were 36 patients who had atrial arrhythmias at one-year follow-up, representing a 24% recurrence rate. In the actively cooled group, 11 patients had recurrence of arrhythmia at one-year, representing a 12% recurrence rate (P=0.02). Conclusions: Patients treated with active esophageal cooling during left atrial ablation had a significantly lower atrial arrhythmia recurrence rate at one-year follow-up when compared to patients provided with traditional LET monitoring during left atrial ablation procedures.

Abstract 14149: High-Power, Low-Duration and Fluoro-Less Atrial Fibrillation Radiofrequency Ablation

Introduction: High power radiofrequency ablation (RFA), a novel technique, is recently being employed for pulmonary vein isolation (PVI) for atrial fibrillation (AF). This study aimed to report our center’s procedural data and preliminary results of a high power RFA technique for AF without fluoroscopic guidance. Methods: Symptomatic AF patients were consecutively enrolled in this prospective observational study and underwent PVI. Ablation index (AI) was marginally used for at least 400 on the posterior wall and 500 on the anterior wall or 15 seconds total at 50 Watt ablation power, whichever came first. Contact-force catheter and esophageal temperature was used during the procedure. Post-ablation esophageal endoscopy was utilized. PVI was performed using CARTO and the ST SF D/F curve ablation catheter in a temperature-controlled mode. Results: PVI was achieved in all (n = 36, mean age: 68±11.3 years, female: 29%, CHADsVASc: 2.8±1.5, LA volume index:60.4±17.2 mL/m2). 29(80%) patients had paroxysmal AF. For left wide antral circumferential ablation (WACA); total duration was 7.4±11.3 min, total ablation sites were 49.9±11.2, average contact force was 9.97±2.2 g and average AI was 363.9±20.5. For right WACA total duration was 6.4±2 min, total ablation sites were 45.6±15.3, average contact force was 13.0±3.5 g and average AI was 403.6±32.9. WACA technique was employed for paroxysmal AF, additional ablation lines were targeted for persistent AF. For the entire flouro-less, 50W study population, average AI was 382.2±26.6, total ablation duration was 18.1±4.7 min, total ablation sessions were 118.4±33.4 and average temperature was 38.7±1.4 degree Celsius. During in-hospital follow-up no major complications such as death, stroke, tamponade, or atrio-esophageal fistula occurred. Conclusions: 50 watts fluoro-less AF RFA is a safe and efficient procedure.

Abstract 11284: Predicting Thermal Injury by Machine Learning Analysis of Luminal Esophageal Temperature Patterns in Atrial Fibrillation Ablation

Introduction: Luminal esophageal temperature (LET) monitoring during catheter ablation for atrial fibrillation (AF) is widely used to reduce the incidence of esophageal thermal injury (ETI). We sought to assess whether specific patterns of LET variation are associated with ETI. Methods: The CIRCA-S multi-sensor probe was used to record LET in AF patients undergoing radiofrequency (RFA) or cryoballoon ablation (CBA) ( Fig A ). Patients underwent upper endoscopy one day after ablation. LET data was analyzed for patterns associated with ETI ( Fig B ). A random forest classifier with 5x stratified cross validation was trained to predict ETI, and SHapley Additive exPlanations (SHAP) analysis was used to assess feature importance in the prediction of ETI. Results: A total of 90 patients (63% paroxysmal AF; 27% female) were included. Among them, 68 patients underwent RFA, and 22 patients CBA. ETI was detected in 11 patients (10 RFA and 1 CBA). In case of RFA, the highest LET recorded was similar between patients who had an ETI and those who did not (40.4 [39.1, 41] vs 40.6 [40.1, 41], p=0.4); however, the rate of LET rise for the highest recorded peak was higher (0.08 [0.03, 0.12] vs 0.02 [0.01, 0.05]; p=0.02) and area under the curve (AUC) for highest peak was smaller (412.5 [206.8, 634.1] vs 545.5 [369.9, 855.1]; p=0.066) in patients who had ETI. In case of CBA, the patient with ETI had a faster LET decline (0.12 vs 0.07 [0.02, 0.14]), and a smaller AUC for the lowest trough (2491.3 vs 2629.3 [1712.6, 5283.2]) compared to patients who had no ETI. SHAP analysis revealed that for the overall population, rate of LET change was the most important feature in the prediction of ETI ( Fig C ), and that a rate of LET change &gt;0.1°C/s is most predictive of ETI ( Fig D ). Conclusion: Rate of LET change and AUC for the recorded temperature are more important predictors of ETI compared to absolute peak temperatures. Prospective studies guided by these parameters are needed to demonstrate their efficacy in reducing ETI.

Abstract 15077: Reconnection of Pulmonary Veins and Left Atrial Posterior Wall Following Catheter Ablation for Atrial Fibrillation in Real-World Patients: Registry Data From a High-Volume Center

Introduction: Durable isolation of the pulmonary veins (PV) and the left atrial posterior wall (LAPW) are considered as key determinants of long-term success after catheter ablation in AF patients. Objective: We aimed to evaluate the PV and LAPW reconnection rate in real-world patients undergoing redo-ablation at our center. Methods: Consecutive AF patients that underwent their first AF ablation at our center from 2015-19 were included in this analysis. At the index procedure, all received electrical isolation of PVs and the LAPW area between the PVs, using radiofrequency (RF) ablation. Procedure was conducted with 3.5-mm irrigated-tip catheter guided by circular mapping catheter, intra-cardiac echocardiography and a 3-D mapping system. RF energy was delivered with a maximum temperature setting of 42 0 C, contact force of 10g and a power of up to 45W. Posterior wall isolation was performed using multiple ablation points covering the whole posterior wall. An esophageal probe was utilized in all patients to monitor esophageal temperature during ablation in the LAPW in close proximity to the esophagus. Complete abolition of all PV potentials rather than decrease in the amplitudes was the end point and confirmed by entrance and/or exit block. All patients were followed up prospectively for 2 years with quarterly evaluation during the first year and bi-annually afterwards and the data was collected in our IRB-approved AF registry. Recovery of conduction in the PVs and LAPW were assessed at the redo procedure using pacing or incremental isoproterenol infusion of 20- 30μg/min for 15-20min. Results: During the study period, 6,817 AF ablation procedures were performed at our institution of which 3,113 AF patients undergoing their first catheter ablation were included in the analysis and prospectively followed up for 2 years. Baseline characteristics of the study population is given in Table 1. At 23.1±12.8 months of follow-up, 614 (19.7%) patients had received redo-ablation, of which 139 (22.6%) had one or more PV or LAPW reconnected. Conclusion: In this series, with experienced operators performing the procedures, the rate of recovery of conduction in the PVs and LAPW was low compared to the reported high incidence rate in the literature.

An Esophageal Cooling Device During Radiofrequency Ablation for Atrial Fibrillation-A Comparison Between Reactive and Proactive Esophageal Cooling.

Esophageal thermal injury is one of the most feared risks of ablation of the posterior left atrium despite the various devices used to monitor esophageal temperature or deviate the esophagus. Reactive cooling, in which cold water is manually instilled into the esophagus via an orogastric tube in response to rises in luminal esophageal temperature (LET), has been used by operators, but the availability of a dedicated esophageal cooling device offers the ability to provide proactive esophageal cooling without having to react to individual temperature rises in the esophagus. The objective of this study was to evaluate the feasibility of using a commercially available esophageal cooling device to provide esophageal protection during left atrial catheter ablation, then to compare this approach to standard LET monitoring with reactive cooling via manual cold-water instillation. In this study, we randomized 6 patients undergoing catheter ablation for atrial fibrillation. Three patients received the standard of care for our site (use of a single-sensor temperature probe, with adjunct ice-water instillation for any temperature increases of >1°C). Three patients underwent standard ablation after placement of the esophageal cooling device at a circulating water temperature of 4°C, without the use of any esophageal temperature monitoring. All patients underwent transesophageal echocardiography and esophagogastroduodenoscopy on the day prior to the ablation, followed by a second esophagogastroduodenoscopy the day after. The 6 patients in this study were enrolled between March and August 2018. In the 3 control patients, 1 had no evidence of esophageal mucosal damage, 1 had diffuse sloughing of the esophageal mucosa and multiple ulcerations, and 1 had a superficial ulcer with a large clot. Both patients with lesions were classified as 2a cases using the Zargar grading scheme for caustic injury. In the 3 patients treated with the cooling device, 1 had no evidence of esophageal mucosal damage, 1 had esophageal erythema (Zargar grade 1), and 1 had a solitary Zargar grade 2a lesion. At 3 months of follow-up, 1 patient in each group had recurrence of atrial fibrillation. Although a number of subsequent studies have confirmed the reduction of esophageal injury with the use of proactive esophageal cooling, this study is the only one to date to compare reactive cooling (via manual cold-water instillation) and proactive cooling (via a dedicated esophageal cooling device). Moreover, this is the first study to support the feasibility of using a dedicated cooling device for this purpose and provides the basis for further investigation.

Targeted Temperature Management Using Esophageal Cooling.

Although specific temperature targets are debated, targeted temperature management (TTM) is a common treatment for postcardiac arrest patients. However, consistently implementing a TTM protocol is challenging, especially in a community hospital. Often, the protocols described in the literature include labor- and cost-intensive methods that are not feasible or sustainable in many health care settings. Esophageal temperature management (ETM) is a TTM method that can be easily utilized alone or combined with surface methods. We sought to evaluate ETM in a cohort of patients treated with TTM after cardiac arrest. Chart reviews were conducted of all patients treated with ETM after cardiac arrest at our community medical center. Initial patient temperature, time to target, supplemental methods (water blankets, chest wraps, or head wraps), and patient survival were extracted for analysis. A total of 54 patients were treated from August 2016 to November 2018; 30 received ETM only, 22 received supplemental cooling, and 2 had treatment discontinued before reaching target due to recovery. Target temperatures ranged from 32°C to 36°C, depending on provider preference. The median time to target temperature for the entire cohort was 219 minutes (interquartile range [IQR] 81-415). For the cohorts without, and with, supplemental cooling modalities, the median time to attain target temperature was 128 minutes (IQR 71-334), and 285 minutes (IQR 204-660), respectively. Survival to intensive care unit discharge was 51.9% for the entire cohort. Survivors exhibited longer times to achieve goal temperature (median 180 minutes in nonsurvivors vs. 255 minutes in survivors). ETM attains target temperature at a rate consistent with current guidelines and with similar performance to alternative modalities. As in other studies, surviving patients required longer times to reach target temperature.

Comparison of tracheal temperature and core temperature measurement in living donor liver transplant recipients: a clinical comparative study

BackgroundBody temperature is a vital sign, and temperature monitoring during liver transplantation is important. Tracheal temperature can be measured via an endotracheal tube with a temperature sensor on the cuff of the tube. This study aimed to investigate the accuracy and trending ability of tracheal temperature measurement compared to those of the core temperature measured at the esophagus and pulmonary artery (PA) in living donor liver transplant recipients.MethodsTwenty-two patients who underwent living donor liver transplantation (LDLT) were enrolled. Patients were intubated using an endotracheal tube with a temperature sensor placed on the inner surface of the tube cuff. Tracheal, esophageal, and PA temperatures were recorded at five time points corresponding to the different phases of liver transplantation. The tracheal and esophageal, tracheal and PA, and esophageal and PA temperatures were compared using Bland–Altman analysis, four-quadrant plot/concordance analysis, and polar plot analysis.ResultsBland–Altman analysis showed an overall mean bias (95% limits of agreement) between tracheal and esophageal temperatures of -0.10 °C (-0.37 °C to 0.18 °C), with a percentage error of 0.27%; between tracheal and PA temperatures, -0.05 °C (-0.91 °C to 0.20 °C), with a percentage error of -0.15%; and between esophageal and PA temperatures, 0.04 °C (-0.27 °C to 0.35 °C), with a percentage error of 0.12%. The concordance rates between tracheal and esophageal temperatures, tracheal and PA temperatures, and esophageal and PA temperatures were 96.2%, 96.2%, and 94.94%, respectively. The polar plot analysis showed a mean angular bias (radial limits of agreement) of 4° (26°), -3° (13°), and 2° (21°).ConclusionsMonitoring core temperature at the inner surface of the endotracheal tube cuff is accurate in all phases of LDLT with good trending ability; thus, it can be an excellent alternative for monitoring during LDLTs.

Significant procedure length reduction when utilizing active esophageal cooling – a six-year single center study

Abstract Background A number of factors can influence procedure duration of left atrial ablation for the treatment of atrial fibrillation (AF). In addition to ablation techniques, the use of auxiliary tools such as intraoperative fluoroscopy and luminal esophageal temperature (LET) monitoring may impact procedure duration. However, unlike recent trends toward zero-fluoroscopy procedures, there has not been a widespread transition to alternative means of esophageal protection. Multi sensor LET monitoring leads to frequent pauses during ablations when dangerous esophageal temperatures have been reached. Although an increased risk of esophageal injury when utilizing LET monitoring as compared to active esophageal cooling has been suggested in recent studies, the degree to which LET monitoring impacts procedure duration has not been well documented. Consequently, we aimed to compare procedure duration in a large single center before and after active esophageal cooling was implemented in place of LET monitoring. Objective Review procedural timing data at a single large hospital before and after the implementation of active esophageal cooling in place of LET monitoring, and compare differences in procedure duration. Methods Using an existing hospital registry of ablation procedures, we obtained procedure durations for left atrial ablations for AF before and after the implementation of active esophageal cooling into the hospital protocol. Data was collected with IRB approval from a single hospital from January 2015 through November 2021. Prior to September 2018, multi-sensor LET monitoring was utilized in all patients, whereas all patients afterwards were treated with active esophageal cooling. Results Data was analyzed from a total of 412 patients. LET monitoring was utilized with 176 patients, while active esophageal cooling was utilized with 236 patients. In the LET monitored group the median procedure length was 191 minutes with an interquartile range (IQR) of 91 minutes. In the actively cooled group, the median procedure length was 147 minutes with an IQR of 61 minutes. This represents a median difference of 44 minutes, or 23% of total procedure time (p&amp;lt;0.001). Conclusion When compared to LET monitoring, the use of active esophageal cooling is associated with a significant time savings in PVI procedures. Funding Acknowledgement Type of funding sources: Private company. Main funding source(s): Attune Medical

Comparison of the acute outcome of two cryoballoon technologies for pulmonary vein isolation: An updated systematic review and meta-analysis

Initial experience suggests that the POLARx cryoballoon system (Boston Scientific) has a similar procedural efficacy and safety as Arctic Front Advance Pro (AFA-Pro, Medtronic). We performed an updated systematic review and meta-analysis comparing POLARx and AFA-Pro. Embase, MEDLINE, Web of Science, Cochrane, and Google Scholar databases were searched until 12/01/2022 for studies comparing POLARx versus AFA-Pro in patients undergoing pulmonary vein (PV) isolation for AF. A total of 8 studies, involving 1146 patients from 11 European centers were included (POLARx n = 317; AFA-Pro n = 819). There were no differences in acute PV isolation, procedure time, fluoroscopy time, ablation time, minimal esophageal temperature, and risk of phrenic nerve palsy or thromboembolic events. Balloon nadir temperatures were lower for POLARx in all PVs. Compared with AFA-Pro, POLARx had a higher rate of first freeze isolation in the left inferior PV (LIPV) (odds ratio [OR]: 2.60; 95 % confidence interval [CI]: 1.06 to 6.43; P = 0.04), higher likelihood of time-to-isolation (TTI) recording in LIPV (OR: 2.91; 95 % CI: 1.54 to 5.49; P = 0.001) and right inferior PV (OR: 3.23; 95 % CI: 1.35 to 7.74; P = 0.008). In contrast, the TTI in LIPV was longer with POLARx in comparison to AFA-Pro (mean difference: 7.61 sec; 95 % CI 2.43 to 12.8 sec; P = 0.004). In conclusion, POLARx and AFA-Pro have a similar acute outcome. Interestingly, there was a higher rate of TTI recording in the inferior PVs with POLARx. This updated meta-analysis provides new safety data on esophageal temperature and thromboembolic events.

PRIOR SARS-COV-2 INFECTION DOES NOT INCREASE RISK OF EXERTIONAL HEAT STROKE OR CAUSE DETRIMENTAL CHANGES IN PLASMA CYTOKINES

BACKGROUND: SARS-CoV-2 is a viral infection that can cause systemic inflammation with fever symptoms and impaired respiration. Animal models suggest that some forms of viral infection can increase risk for exertional heatstroke (EHS), possibly via reductions in the cellular stress response. PURPOSE: To determine if persons with prior clinical diagnosis of SARS-CoV-2 infection exhibit any differences in thermoregulatory or cardiopulmonary responses to 60 min of cycling exercise in hot, dry conditions. METHODS: Nine participants (Age: 22 ± 2 years, Stature: 1.74 ± 0.02 m, Mass: 71.3 ± 3.9 kg, VO2max: 46 ± 2 mL/kg/min) completed 1 hr of cycling in an environmental chamber (35 °C / 35% RH) at an intensity that elicited 9.0 W/kg of metabolic heat production. Four participants had been previously diagnosed with SARS-CoV-2; the other five served as Control. Heart rate (HR), esophageal temperature (Tc), mean body temperature (Tb), physiological strain index (PSI), minute ventilation (Ve), and oxygen consumption (VO2) were examined throughout exercise. Interleukin 1 Receptor Antagonist (IL-1RA) and Interleukin 6 (IL-6) were assayed from plasma samples collected before (Pre), after (Post), and 1 h after (1-Post) exercise. Data were analyzed with RM-ANOVA and Tukey Post Hocs. RESULTS: As compared to Control, persons with prior SARS-CoV-2 infection did not exhibit greater elevations in HR (84 ± 4% of HRmax vs 87 ± 2% of HRmax), Tc (1.4 ± 0.3 °C vs 1.1 ± 0.2 °C), Tb (1.2 ± 0.3 °C vs 1.1 ± 0.2 °C), PSI (6.9 ± 1.0 vs 6.7 ± 0.6), Ve (38.8 ± 4.3 L/min vs 40.5 ± 0.3 L/min) or VO2 (23.8 ± 1.1 ml/kg/min vs 21.0 ± 1.4 ml/kg/min) during 1 hr of cycling exercise at a fixed rate of heat production in hot/dry ambient conditions [all P > 0.05]. There were no differences in plasma IL-1RA between the two groups at any time-point [all P > 0.05]. Despite having similar plasma IL-6 concentrations at baseline (0.5 ± 0.2 pg/ml vs 0.6 ± 0.3 pg/ml), the increase in IL-6 post-exercise was two-fold greater in Control (5.9 ± 1.6 pg/ml vs 2.8 ± 0.6 pg/ml; P = 0.04). CONCLUSIONS: Our data do not provide any evidence of an adverse response to exertional heat stress in persons with prior SARS-CoV-2 infection. Thermal and cardiovascular strain responses were not impaired. Plasma IL-6 was reduced following exercise, but the physiologic relevance of that change remains to be determined.

Reduced Procedure Time and Variability with Active Esophageal Cooling During Radiofrequency Ablation for Atrial Fibrillation.

Various methods are utilized during radiofrequency (RF) pulmonary vein isolation (PVI) for the treatment of atrial fibrillation (AF) to protect the esophagus from inadvertent thermal injury. Active esophageal cooling is increasingly being used over traditional luminal esophageal temperature (LET) monitoring, and each approach may influence procedure times and the variability around those times. The objective of this study is to measure the effects on procedure time and variability in procedure time of two different esophageal protection strategies utilizing advanced informatics techniques to facilitate data extraction. Trained clinical informaticists first performed a contextual inquiry in the catheterization laboratory to determine laboratory workflows and observe the documentation of procedural data within the electronic health record (EHR). These EHR data structures were then identified in the electronic health record reporting database, facilitating data extraction from the EHR. A manual chart review using a REDCap database created for the study was then performed to identify additional data elements, including the type of esophageal protection used. Procedure duration was then compared using summary statistics and standard measures of dispersion.A total of 164 patients underwent radiofrequency PVI over the study timeframe; 63 patients (38%) were treated with LET monitoring, and 101 patients (62%) were treated with active esophageal cooling. The mean procedure time was 176 min (SD of 52 min) in the LET monitoring group compared to 156 min (SD of 40 min) in the esophageal cooling group (P = 0.012). Thus, active esophageal cooling during PVI is associated with reduced procedure time and reduced variation in procedure time when compared to traditional LET monitoring.

Esophageal safety in CLOSE-guided 50 W high-power-short-duration pulmonary vein isolation:The PREHEAT-PVI-registry.

Pulmonary vein isolation (PVI) using high-power-short-duration (HPSD) radiofrequency ablation (RF) is emerging as the standard of care for treatment of atrial fibrillation (AF). While procedural short-term to midterm efficacy and efficiency are very promising, this registry aims to investigate esopahgeal safety using an optimized ablation approach. In a single-center experience, 388 consecutive standardized first-time AF ablation were performed using a CLOSE-guided-fixed-50 W-circumferential PVI and substrate modification without intraprocedural esophageal temperature measurement. Three hundred patients underwent postprocedural esophageal endoscopy to diagnose and grade endoscopically detected esophageal lesions (EDEL) and were included in the analysis. EDEL were detected in 35 of 300 patients (11.6%), 25 of 35 were low-grade Kansas-city-classification(KCC) 1 lesions with fast healing tendencies. Sixpatients suffered KCC 2a lesions, 4 patients had KCC 2b lesions (1.3% of all patients). No esophageal perforation or fistula formation was observed. Patient baseline characteristics, especially patients age, gender, and body mass index did not influence EDEL incidence. Additional posterior box isolation did not increase the incidence of EDEL. In patients diagnosed with EDEL, mean catheter contact force during posterior wall ablation was higher (11.9 ± 1.8 vs. 14.7 ± 3 g, p < .001), mean RF duration was shorter (11.9 ± 1 vs. 10.7 ± 1.2 s, p < .001), while achieved ablation indexwas not different between groups (434 ± 4.9 vs. 433 ± 9.5, n.s.). Incidence of EDEL after CLOSE-guided-50 W-HPSD PVI is lower compared to historical cohorts using standard-power RF settings. Catheter contact force during posterior HPSD ablation should not exceed 15 g.

Prospective comparative analysis of noninvasive body temperature monitoring using zero heat flux technology (SpotOn sensor) compared with esophageal temperature monitoring during pediatric surgery.

Maintaining body temperature in pediatric patients is critical, but it is often difficult to use currently accepted core temperature measurement methods. Several studies have validated the use of the SpotOn sensor for measuring core temperature in adults, but studies on pediatric patients are still lacking. The aim of this study was to investigate the accuracy of the SpotOn sensor compared with that of esophageal temperature measurement in pediatric patients intraoperatively. Children aged 1-8 years with American Society of Anesthesiology Physical Condition Classification I or II scheduled to undergo elective ear surgery for at least 30 min under general anesthesia were enrolled. Body core temperature was measured every 15 min after induction till the end of anesthesia with an esophageal probe, axillary probe, and SpotOn sensor. We included 49 patients, providing a total 466 paired measurements. Analysis of Pearson rank correlation between SpotOn and esophageal pairs showed a correlation coefficient (r) of 0.93 (95% confidence interval [CI] 0.92-0.94). Analysis of Pearson rank correlation between esophageal and axillary pairs gave a correlation coefficient (r) of 0.89 (95% CI 0.87-0.91). Between the SpotOn and esophageal groups, Bland-Altman analysis revealed a bias (SD, 95% limits of agreement) of -0.07 (0.17 [-0.41-0.28]). Between the esophageal and axillary groups, Bland-Altman analysis showed a bias (SD, 95% limits of agreement) of 0.45 (0.22 [0-0.89]). In pediatric patients during surgery, the SpotOn sensor showed high correlation and agreement with the esophageal probe, which is a representative core temperature measurement method.

Abstract P2101: Time Dependence Of Esophageal Injury With And Without Proactive Cooling During High-power Short-duration Radiofrequency Ablation

Background: Recent data suggest that luminal esophageal temperature (LET) monitoring during high-power short-duration (HPSD) ablation may be inadequate to prevent esophageal thermal injury during radiofrequency (RF) ablation. This is due in part to delayed responses to thermal latency and the continued temperature rise that occurs in tissues even after the cessation of RF energy with HPSD settings. Proactive esophageal cooling has been shown to reduce severe esophageal thermal injury during medium-power medium-duration RF ablation, but less is known about the effects in HPSD ablation. Objective: We aimed to quantify the time course of esophageal damage in scenarios with and without proactive esophageal cooling, hypothesizing a reduction in the resulting tissue damage with proactive esophageal cooling. Methods: Using a computer model of RF ablation in the left atrium adjacent to the esophagus, we calculated temperature over time using ablation power of 50 W for 10 s and 90 W for 4 s. We then determined the fraction of resulting damage to esophageal tissue via the Arrhenius equation and by the percentage of tissue above lethal isotherm temperature of 50°C. Transmurality of injury was then plotted over time, and results were compared between ablation with and without proactive esophageal cooling. Results: Esophageal damage increased even after the cessation of RF energy, suggesting significant thermal latency effects under HPSD ablation. Lesion growth continued for &gt;10 s after cessation of 50 W ablation energy, and for &gt;12 s after cessation of 90 W ablation energy without cooling. With proactive cooling, lesion growth after cessation of ablation energy was essentially halted. Without esophageal cooling, maximum injury transmurality reached 79% with 50 W, and 58% with 90 W. With esophageal cooling, injury transmurality remained below 20% with 50 W, and 10% with 90 W, representing reductions of 75% and 83%, respectively. Conclusions: RF ablation using HPSD settings demonstrates significant latency of effect, with tissue damage and lesion growth continuing beyond the cessation of application of RF energy. Proactive esophageal cooling significantly dampens this effect, reducing esophageal injury by up to 83%.

Supplemental reflective blankets and wool socks help maintain body temperature in dogs undergoing celiotomy procedures: a prospective randomized controlled clinical trial.

To compare results for body (esophageal) temperature measurements obtained during celiotomy in normothermic (presurgical) canine patients receiving routine heat support versus routine heat support plus supplemental support (consisting of covering the thorax in a reflective blanket and placing reflective blankets plus wool socks on 3 limbs) in a prospective randomized controlled clinical trial. 44 dogs requiring celiotomy that were presented sequentially to an emergency and specialty referral veterinary hospital. The 44 dogs undergoing celiotomy were randomly assigned to 2 groups. The control group received routine intraoperative heat support consisting of a circulating warm water blanket and either a towel or blanket. The supplemental group received the same routine heat support plus a reflective blanket covering the cervical and thoracic regions and reflective blankets wrapped around 3 limbs and covered with wool socks from the digits to the axillary or inguinal region. Mean esophageal temperature for both the control and supplemental groups dropped throughout celiotomy. Esophageal temperature measurements at several time points were significantly higher for the supplemental group than for the control group. The lowest temperature measurement for the supplemental group, adjusted for initial esophageal temperature and procedure duration, was significantly higher by 0.8 °C than that for the control group. Covering the cervical and thoracic regions with a reflective blanket and wrapping limbs in reflective blankets and wool socks is an affordable adjunctive method to provide passive heat support and minimize perioperative hypothermia in canine patients undergoing celiotomy.