This protocol follows the guidelines of our institution&#39;s human research ethics committee.
1. Assessment Guidelines Prior to Placement
NOTE: Although there are no formal contraindications listed in the U.S. labelling, it is recommended that the esophageal temperature management device be used with caution in patients with known esophageal deformity, evidence of esophageal trauma, and in patients known to have ingested acidic or caustic poisons within the prior 24 hours.
<ol>
	<li>Obtain all equipment, including appropriate heat exchange unit, the esophageal temperature management device, an appropriate securement device, water-based lubrication packets, and a circumferential bite block.</li>
	<li>Place Foley thermistor and/or rectal temperature probe and connect one to the heat exchange unit. A second temperature source is recommended for verification, and may be connected to the patient monitor.</li>
	<li>Connect the esophageal temperature management device to the appropriate heat exchanger, power on the unit, set the patient target temperature according to hospital protocol, and place the heat exchanger in automatic mode. Ensure that water is flowing through the esophageal temperature management device and confirm that no leaks are present.</li>
</ol>
2. Device Insertion
<ol>
	<li>Measure the appropriate insertion depth for the esophageal temperature management device by extending it from the patient&#39;s lips to the earlobe and then from the earlobe to the tip of the xiphoid process; mark the insertion depth on the device (Figure 2).</li>
</ol>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/56579/56579fig2.jpg" /> 
Figure 2. Measuring an esophageal temperature management device for placement. This schematic illustrates the appropriate procedure for determining device placement depth, as described in step 2.1. <a href="//cloudfront.jove.com/files/ftp_upload/56579/56579fig2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol start="2">
	<li>Lubricate the esophageal temperature management device generously (approximately 15 cm of the distal end) with water-soluble lubricant (Figure 3).</li>
</ol>
<img alt="Figure 3" class="xfigimg" src="/files/ftp_upload/56579/56579fig3.jpg" /> 
Figure 3. Lubricating the esophageal temperature management device. This schematic illustrates the appropriate procedure for applying water soluble lubrication to the device prior to insertion, as described in step 2.2. <a href="//cloudfront.jove.com/files/ftp_upload/56579/56579fig3large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol start="3">
	<li>Place the patient as flat as tolerated and insert the esophageal temperature management device using gentle pressure posteriorly and downwards through the mouth, past the oropharynx, and into the esophagus. A gentle jaw thrust may be required to assist passage of the device.&#160;If clinically feasible, the addition of slight neck extension, induced with support under the shoulders if needed, may further ease passage of the device. Advance the device with light pressure until the required length of tube has been inserted. Secure the bite block in place (Figure 4).</li>
</ol>
<img alt="Figure 4" class="xfigimg" src="/files/ftp_upload/56579/56579fig4v2.jpg" /> 
Figure 4. Inserting the esophageal temperature management device. This schematic illustrates the appropriate patient positioning for inserting the device, as described in step 2.3. <a href="//cloudfront.jove.com/files/ftp_upload/56579/56579fig4v2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol start="4">
	<li>Confirm placement of the esophageal temperature management device in accordance with hospital protocol.
	<ol>
		<li>Inject air with a syringe through the central lumen while auscultating over the stomach for a &#34;swoosh&#34; or a &#34;burp&#34; indicating gastric placement.</li>
		<li>Aspirate gastric contents with a syringe through the central lumen.</li>
		<li>Confirm the location and placement with an x-ray.</li>
	</ol>
	</li>
	<li>Secure with a securement device or tape in accordance with hospital protocol. Ensure the tube and tube set connections are not in contact with the patient&#39;s skin, as direct contact between the tube and exposed skin may cause shivering.</li>
	<li>For stomach decompression, connect the central lumen to low-intermittent suction using standard suction tubing.</li>
</ol>
3. Temperature management &#8211; cooling
<ol>
	<li>Ensure heat exchanger is set to automatic mode and the appropriate goal temperature (typically from 32 &#176;C to 37&#160;&#176;C, depending on institutional protocol) is set.</li>
	<li>Initiate shivering prophylaxis with medications as per unit protocol (prophylactic intervention is recommended with non-sedating medications to start; for example, acetaminophen, buspirone, magnesium, and skin counterwarming).</li>
	<li>Evaluate for shivering using the Bedside Shivering Assessment Scale at regular intervals, or anytime temperature reduction is not proceeding as expected. Shivering occurs in a caudal progression and will first be identified at the mandible or pectoralis muscles; early intervention is imperative. Additional treatment for shivering may include meperidine, dexmedetomidine, fentanyl, propofol, or neuromuscular blockade.</li>
</ol>
4. Temperature management &#8211; maintenance
<ol>
	<li>Monitor and record water temperature hourly; if the water temperature drops below 10 &#176;C for 1 h (or more than once when patient is at target temperature), first assess for shivering.</li>
	<li>Periodically reposition the esophageal temperature management device in accordance with hospital protocol.</li>
</ol>
5. Temperature management &#8211; warming
<ol>
	<li>Follow local hospital guideline for rewarming rate if rewarming from intentional hypothermia.</li>
	<li>Set a maximum rewarming rate if rewarming from accidental hypothermia, or preventing perioperative hypothermia.</li>
</ol>
6. Troubleshooting
NOTE: A kink or pinch in the system may cause an occlusion alert on the external heat exchanger. If the cause cannot be found, stop treatment and remove the esophageal temperature management device.
<ol>
	<li>Utilize standard approaches for clearing blocked gastric tubes if the central lumen of the esophageal temperature management device becomes clogged or blocked; if unsuccessful, replace the device.</li>
	<li>If there is a discrepancy greater than 0.5 &#176;C between temperature sources, pause therapy to investigate the issue.</li>
	<li>As leak in the system may cause an increase in accumulated liquid in the suction canister, if a larger than expected volume of water accumulates in the suction canister, stop treatment and remove the esophageal temperature management device to examine for leaks. 
	NOTE: Factors which may affect warming or cooling include body mass, environmental conditions, shivering, and clinical condition; patients greater than 120 kg may exhibit slower responses to intended temperature changes, and smaller patients may take longer to warm.</li>
	<li>If the patient is not cooling or warming as expected:
	<ol>
		<li>Ensure the esophageal temperature management device is at the correct depth.</li>
		<li>Ensure adequate water flow and that the device is cold or warm to touch (as appropriate).</li>
		<li>Ensure the external heat exchanger is set appropriately in automatic mode with desired target temperature and appropriate water temperature (4 &#176;C to 42 &#176;C).</li>
		<li>Confirm the temperature probe is intact and accurate; check with secondary source.</li>
		<li>Check the patient for heat generation (shivering or fever generation for example), heat loss (hemodynamic instability or medication administration) and ensure the environmental temperature is consistent with temperature modulation goal.</li>
	</ol>
	</li>
</ol>
7. Device removal
<ol>
	<li>Press &#34;Monitor&#34; to stop the external heat exchanger, close the clamps if present, and withdraw the device.</li>
	<li>Disconnect the device from the tube set connections and dispose as per institutional policy.</li>
	<li>Turn off the heat exchange unit.</li>
</ol>

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The authors Melissa Naiman, Maria Gray, and Erik Kulstad are employees of Attune Medical that produces the esophageal temperature management device described in this manuscript. The authors Ahmed Hegazy, Joseph Haymore, Neeraj Badjatia, and Andrej Markota received complimentary devices to conduct clinical evaluations.

Modification and troubleshooting required for this protocol is generally limited to that featured above, and involves the typical monitoring of patient care employed in critical care settings. Modulating core temperature is critical to patient outcomes in a growing range of clinical scenarios. These include the intentional induction of hypothermia from normothermia, rewarming from inadvertent or intentional hypothermia, and actively maintaining normal body temperature (i.e., normothermia) during conditions in which inadvertent hypothermia are common, such as in the operating room. As specific clinical examples, patients who suffer ischemia-reperfusion injury, such as occurs during cardiac arrest, benefit from cooling (generally to temperatures below normal body temperature) followed by gentle rewarming and fever prevention for up to 3 days after resuscitation28,29,30. Neonates suffering from hypoxic ischemic encephalopathy obtain improved outcomes if cooled below normal body temperature31. The cooling of kidney donors after neurologic death, prior to organ transplant, has been shown to reduce the rate of delayed graft function32. Controlling fevers in septic shock patients may reduce vasopressor requirements and contribute to reducing early mortality33. Maintaining normothermia in patients undergoing surgical procedures reduces surgical wound infections, myocardial complications, blood loss, and transfusion requirements, while shortening length of stay and reducing the likelihood of death10,11,16.
Limitations of the technique include challenges encountered in managing critical care patients. While targeted temperature management promotes good outcomes, the most common temperature modulation techniques introduce risks to patients and logistical challenges to providers (including difficulties in placement, bloodstream infections, blood clots, skin damage, and cost). Esophageal temperature management is designed to overcome these shortcomings34,35,36. When appropriately managed, the esophageal temperature management device does not come into contact with the vasculature (as do the intravascular temperature modulation devices) or skin (as do the surface temperature modulation devices), thereby avoiding blood clots, bloodstream infection, and skin degradation. The device can be placed quickly by a variety of healthcare providers, typically in a matter of minutes21,37. The insertion technique mimics standard orogastric tube placement, which minimizes workflow disruptions that might delay therapy initiation. Using a core approach also appears to pose significantly less shivering burden than surface approaches27,38,39,40&#160;. This has the advantage of reducing sedative and anti-shivering medication costs, which then shortens the patient length of stay via quicker awakening from the lower degree of sedation required. These features, considered in concert with the clinical performance described above, support esophageal temperature management as a viable option for providers in the emergency department, intensive care unit, and operating room. A growing set of data published on the device likewise supports this new approach21,22,23,24,27,41.
Critical steps within the protocol include initiating flow within the device prior to insertion, providing adequate lubrication to the device in order to assure easy placement, performing gastric suctioning and decompression to allow maximum contact between device and patient, and addressing any patient shivering that may develop. Following this protocol will provide optimum results and allow a high degree of performance and safety in the care of this important patient population.

There is significant need for patient temperature management when treating a wide range of conditions, including cardiac arrest, refractory or recurrent fever, neurogenic fever, and major surgery. In the United States, a half-million cardiac arrests annually originate either in the hospital (for example, in patients who are undergoing care for general medical or surgical conditions)1 or out of the hospital (for example, at home or in public venues, who are then brought to the emergency department)2. In both scenarios, patient outcomes are significantly improved when active temperature management is administered3 and targeted temperature management (TTM) has been a standard of care for cardiac arrest since 2005. Over 5 million patients are admitted to intensive care units annually in the U.S4&#160;. Of these, fever develops in up to 45% of non-neurologically injured patients5 and up to 70% of neurologically injured patients6. Fever control in the intensive care unit is associated with improved outcomes and reduced risk of death, because elevated temperature increases metabolic demands, worsens cerebral ischemia, and increases neuronal loss7. At least 10 million surgeries performed annually in the U.S. require active patient warming to prevent inadvertent perioperative hypothermia8. In the operating room, patients undergoing surgery should maintain a body temperature above 36 &#176;C to avoid a large number of adverse effects. Unplanned decreases in body temperature before, during, or after surgery increase blood loss, infections, and hospital length of stay, which adds $7,000 or more per patient to hospitalization costs9,10,11,12.
Despite great clinical need, the most widely administered temperature management protocols demonstrate inadequate performance or introduce significant risk to the patient. Surface devices (such as water blankets, conduction mattresses, and forced-air covers) are cumbersome, have limited heat transfer capacity, and must be removed to allow access to the patient for patient care and procedures. Intravascular devices are invasive, difficult to place, and predispose patients to infections and blood clots. Existing approaches to prevent inadvertent perioperative hypothermia fail to maintain normothermia up to 70% of the time12,13,14,15,16 and a retrospective analysis of post-cardiac arrest cooling found that overall, 30% of patients failed to reach target temperature within 6 h17.
The esophageal approach to patient temperature management offers substantial advantages to existing technologies18. The esophageal temperature management device maintains the functionality of the gastric tube typically placed in the critical care and surgical patient populations. It allows continuous gastric suction and decompression of gas and liquids while adding the ability to control a patient&#39;s temperature safely and efficiently by leveraging the favorable heat exchange environment of the esophagus (Figure 1). Temperature modulation is achieved by connecting the esophageal temperature management device to any of several external heat exchangers (also called chillers) that use water as the coolant. Several vendors produce compatible heat exchangers that are available in hospitals for powering existing temperature control products (most often water blankets). Nurses, nurse practitioners, or physicians typically place an esophageal temperature management device, but it can also be inserted by any provider trained to place a standard orogastric tube. The esophageal temperature management device does not restrict access to the patient, need not be sterile, avoids the risk of needle stick injuries among providers, and avoids the risks of skin complications, bloodstream infections, and blood clots in the patient. Therefore, the purpose of this method is to provide a low-risk alternative method for controlling patient temperature in critical care and operating room settings.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/56579/56579fig1.jpg" /> 
Figure 1. Esophageal temperature management device placement. Device proximity to the great vessels and heart promote efficient heat transfer at the patient&#39;s core. <a href="//cloudflare.jove.com/files/ftp_upload/56579/56579fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

<table><tbody><tr><td>EnsoETM</td><td>Attune Medical</td><td>ECD01</td><td>Device compatible with Gaymar/Stryker Medi-Therm III and Stryker Altrix Precision Temperature Management System</td></tr><tr><td>EnsoETM</td><td>Attune Medical</td><td>ECD02</td><td>Device compatible with Cincinnati SubZero Blanketrol II and Cincinnati SubZero Blanketrol III</td></tr><tr><td>Gaymar/Stryker Medi-Therm III</td><td>Stryker</td><td>n/a</td><td>Compatible heater-cooler with the ECD01</td></tr><tr><td>Cincinnati SubZero Blanketrol II</td><td>Gentherm</td><td>n/a</td><td>Compatible heater-cooler with the ECD02</td></tr><tr><td>Cincinnati SubZero Blanketrol III</td><td>Gentherm</td><td>n/a</td><td>Compatible heater-cooler with the ECD02</td></tr><tr><td>Stryker Altrix Precision Temperature Management System</td><td>Stryker</td><td>n/a</td><td>Compatible heater-cooler with the ECD01</td></tr><tr><td>Water-soluble lubricant</td><td>Various</td><td>n/a</td><td>Standard water-soluble lubricant used to ease insertion of tubes, catheters, and digits</td></tr><tr><td>Securement device</td><td>Various</td><td>n/a</td><td>E.g., Guard360 by PrimeGuard Medical</td></tr></tbody></table>

esophageal heat transfer for patient temperature control and targeted temperature management

Controlling patient temperature is important for a wide variety of clinical conditions. Cooling to normal or below normal body temperature is often performed for neuroprotection after ischemic insult (e.g. hemorrhagic stroke, subarachnoid hemorrhage, cardiac arrest, or other hypoxic injury). Cooling from febrile states treats fever and reduces the negative effects of hyperthermia on injured neurons. Patients are warmed in the operating room to prevent inadvertent perioperative hypothermia, which is known to cause increased blood loss, wound infections, and myocardial injury, while also prolonging recovery time. There are many reported approaches for temperature management, including improvised methods that repurpose standard supplies (e.g., ice, chilled saline, fans, blankets) but more sophisticated technologies designed for temperature management are typically more successful in delivering an optimized protocol. Over the last decade, advanced technologies have developed around two heat transfer methods: surface devices (water blankets, forced-air warmers) or intravascular devices (sterile catheters requiring vascular placement). Recently, a novel device became available that is placed in the esophagus, analogous to a standard orogastric tube, that provides efficient heat transfer through the patient&#39;s core. The device connects to existing heat exchange units to allow automatic patient temperature management via a servo mechanism, using patient temperature from standard temperature sensors (rectal, Foley, or other core temperature sensors) as the input variable. This approach eliminates vascular placement complications (deep venous thrombosis, central line associated bloodstream infection), reduces obstruction to patient access, and causes less shivering when compared to surface approaches. Published data have also shown a high degree of accuracy and maintenance of target temperature using the esophageal approach to temperature management. Therefore, the purpose of this method is to provide a low-risk alternative method for controlling patient temperature in critical care settings.

Aggregate Data 
In terms of cooling, maintenance, and warming rates, esophageal temperature management performs similarly to other advanced temperature management technologies. An analysis of 30 patients treated for up to 36 hours with esophageal temperature management found that the average time to temperature was 2.7 h (SD &#177;2.8 h) and that 96% of temperature readings recorded during the maintenance period were within &#177;1 &#176;C19. Performance was consistent across all protocols, regardless of target temperature (Figure 5, Figure 6, Figure 7, Figure 8). Performance remained consistent with treatment durations longer than 72 h (Figure 9 and Figure 10).
Notable Cases 
Numerous case studies describe the application of esophageal temperature management in practice, including for the treatment of post cardiac arrest ischemia-reperfusion injury, central fever reduction, and maintenance of operative normothermia20,21,22,23,24,25,26,27. Though the esophageal temperature management method was initially conceived in the context of cardiac arrest treatment, the following cases highlight its successful translation into other critical care and perioperative domains.
Case 1: Meningitis 
A 36 year-old woman with a weight of 64 kg was admitted with severe Streptococcus pyrogenes meningitis. Her body temperature increased from 38.2 &#176;C on admission to 40.0 &#176;C six hours later; IV acetaminophen and external cooling blankets proved unsuccessful to adequately decrease temperature.
The esophageal temperature management was initiated at 48 h and the patient&#39;s temperature dropped from 39.4 &#176;C to 37.8 &#176;C in 4 hours. The patient&#39;s temperature continued to drop towards 36.6 &#176;C during the next 12 hours and was maintained between 36 &#176;C and 37 &#176;C for 5 days. Gastroscopy on day 7 revealed no changes attributable to the esophageal temperature management device.
Case 2: Severe Burn and Pyrexia Reversal 
A 49 year-old male weighing 86 kg was admitted with 49% circumferential burns that included full thickness burns to both legs, left arm, and left torso. Two days after admission, the patient was brought to the operating room for surgical procedures that included staged excision and grafting of the leg wounds. Upon placing the esophageal temperature management device and initiating temperature management, the patient&#39;s core temperature was maintained at normothermia while allowing the operating suite temperature to be decreased successfully to 24 &#176;C. Subsequently, on day 22 of the patient&#39;s hospitalization, the patient developed a fever due to E. coli and Candida septicemia resistant to conventional cooling methods. Esophageal temperature management was again initiated, reducing the patient&#39;s temperature from 40 &#176;C to the set point of 38.5 &#176;C, and this temperature was maintained despite restricting the minimum allowable water temperature to 12 &#176;C.
<img alt="Figure 5" class="xfigimg" src="/files/ftp_upload/56579/56579fig5.jpg" /> 
Figure 5. Temperature curve for 33 &#176;C protocol. 17 post-cardiac arrest patients were cooled to 33 &#176;C for 24 h and then rewarmed over a 4 h period to 37 &#176;C. Normothermia was then maintained for another 8 h. Each data point represents a single temperature measurement from a single patient. <a href="https://cloudflare.jove.com/files/ftp_upload/56579/56579fig5large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 6" class="xfigimg" src="/files/ftp_upload/56579/56579fig6.jpg" /> 
Figure 6. Temperature curve for 35 &#176;C protocol. 6 post-cardiac arrest patients were cooled to 35 &#176;C for 24 h and then rewarmed over a 4 h period to 37 &#176;C. Normothermia was then maintained for another 8 h. Each data point represents a single temperature measurement from a single patient. <a href="https://cloudflare.jove.com/files/ftp_upload/56579/56579fig6large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 7" class="xfigimg" src="/files/ftp_upload/56579/56579fig7.jpg" /> 
Figure 7. Temperature curve for refractory fever patients. 4 refractory fever patients were cooled to either 36.5 &#176;C or 38 &#176;C. See inset legend for details. <a href="https://cloudflare.jove.com/files/ftp_upload/56579/56579fig7large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 8" class="xfigimg" src="/files/ftp_upload/56579/56579fig8.jpg" /> 
Figure 8. Temperature curve for perioperative normothermia. 3 severe burn patients (40 - 50% body surface area) were warmed during surgery to prevent inadvertent hypothermia. All patients maintained core temperatures above 36 &#176;C and the ambient temperature in the OR was maintained at 27 &#176;C. <a href="https://cloudflare.jove.com/files/ftp_upload/56579/56579fig8large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 9" class="xfigimg" src="/files/ftp_upload/56579/56579fig9.jpg" /> 
Figure 9. Extended duration esophageal temperature management in cardiac arrest patients. 18 patients were cooled to 33 &#176;C for 24 h and then rewarmed over an 8 h period to 36 &#176;C. Normothermia was then maintained for up to 122 h. <a href="https://cloudflare.jove.com/files/ftp_upload/56579/56579fig9large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 10" class="xfigimg" src="/files/ftp_upload/56579/56579fig10.jpg" /> 
Figure 10. Extended duration esophageal temperature management in refractory fever patients. 18 patients were cooled for up to 454 h according to hospital protocol, including a target temperature of 37.5 &#176;C (green triangles), 37 &#176;C (purple diamonds), 36.7 &#176;C (red triangles), 36.5 &#176;C (orange squares), or 36 &#176;C (blue circles). <a href="https://cloudflare.jove.com/files/ftp_upload/56579/56579fig10large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about Esophageal Heat Transfer for Patient Temperature Control and Targeted Temperature Management at JoVE.com

Esophageal Heat Transfer for Patient Temperature Control and Targeted Temperature Management

This study presents a novel method to provide efficient patient temperature control for cooling or warming patients. A single use, triple lumen device is placed into the esophagus, analogous to a standard orogastric tube, and connects to existing heat exchange units to perform automatic patient temperature management.

Controlling patient temperature is important for a wide variety of clinical conditions. Cooling to normal or below normal body temperature is often ...

esophageal-heat-transfer-for-patient-temperature-control-targeted

Research

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JoVE Journal

JoVE Core

Nursing

Medicine

Unit 1

Vital Signs: Temperature

Healthcare Delivery Systems

SCIENTISTS IN ACTION

24.2K Views.  University of Illinois at Chicago. Deze studie presenteert een nieuwe methode om efficiënte patiënt temperatuurregeling voor koelen of verwarmen van patiënten. Een eenmalig gebruik, triple lumen apparaat wordt geplaatst in de slokdarm, analoog aan een standaard orogastric buis, en verbindt met bestaande warmtewisselaars voor het uitvoeren van de automatisch patiënt temperatuur beheer.

Video: Esophageal Heat Transfer for Patient Temperature Control and Targeted Temperature Management

Bronchial Thermoplasty:  A Novel Therapeutic Approach to Severe Asthma

Bronchial thermoplasty is a non-drug procedure for severe persistent asthma that delivers thermal energy to the airway wall in a precisely controlled manner to reduce excessive airway smooth muscle. Reducing airway smooth muscle decreases the ability of the airways to constrict, thereby reducing the frequency of asthma attacks. Bronchial thermoplasty is delivered by the Alair System and is performed in three outpatient procedure visits, each scheduled approximately three weeks apart. The first procedure treats the airways of the right lower lobe, the second treats the airways of the left lower lobe and the third and final procedure treats the airways in both upper lobes. After all three procedures are performed the bronchial thermoplasty treatment is complete.
Bronchial thermoplasty is performed during bronchoscopy with the patient under moderate sedation. All accessible airways distal to the mainstem bronchi between 3 and 10 mm in diameter, with the exception of the right middle lobe, are treated under bronchoscopic visualization. Contiguous and non-overlapping activations of the device are used, moving from distal to proximal along the length of the airway, and systematically from airway to airway as described previously. Although conceptually straightforward, the actual execution of bronchial thermoplasty is quite intricate and procedural duration for the treatment of a single lobe is often substantially longer than encountered during routine bronchoscopy. As such, bronchial thermoplasty should be considered a complex interventional bronchoscopy and is intended for the experienced bronchoscopist. Optimal patient management is critical in any such complex and longer duration bronchoscopic procedure. This article discusses the importance of careful patient selection, patient preparation, patient management, procedure duration, postoperative care and follow-up to ensure that bronchial thermoplasty is performed safely.
Bronchial thermoplasty is expected to complement asthma maintenance medications by providing long-lasting asthma control and improving asthma-related quality of life of patients with severe asthma. In addition, bronchial thermoplasty has been demonstrated to reduce severe exacerbations (asthma attacks) emergency rooms visits for respiratory symptoms, and time lost from work, school and other daily activities due to asthma.

Bronchial thermoplasty is a non-drug procedure for severe persistent asthma that delivers thermal energy to the airway wall in a precisely controlled manner to reduce excessive airway smooth muscle. Reducing airway smooth muscle decreases the ability of the airways to constrict, thereby reducing the frequency of asthma attacks.

Bronchial thermoplasty is a non-drug procedure for severe persistent asthma that delivers thermal energy to the airway wall in a precisely controlled ...

Near-Infrared Temperature Measurement Technique for Water Surrounding an Induction-heated Small Magnetic Sphere

A technique to measure the temperature of water and non-turbid aqueous media surrounding an induction-heated small magnetic sphere is presented. This technique utilizes wavelengths of 1150 and 1412 nm, at which the absorption coefficient of water is dependent on temperature. Water or a non-turbid aqueous gel containing a 2.0-mm- or 0.5-mm-diameter magnetic sphere is irradiated with 1150 nm or 1412 nm incident light, as selected using a narrow bandpass filter; additionally, two-dimensional absorbance images, which are the transverse projections of the absorption coefficient, are acquired via a near-infrared camera. When the three-dimensional distributions of temperature can be assumed to be spherically symmetric, they are estimated by applying inverse Abel transforms to the absorbance profiles. The temperatures were observed to consistently change according to time and the induction heating power.

A technique utilizing wavelengths of 1150 and 1412 nm to measure the temperature of water surrounding an induction-heated small magnetic sphere is presented.

A technique to measure the temperature of water and non-turbid aqueous media surrounding an induction-heated small magnetic sphere is presented. This ...

Engineering

Magnetic Resonance-Guided High Intensity Focused Ultrasound Generated Hyperthermia: A Feasible Treatment Method in a Murine Rhabdomyosarcoma Model

Magnetic resonance-guided high intensity focused ultrasound (MRgHIFU) is an established method for producing localized hyperthermia. Given the real-time imaging and acoustic energy modulation, this modality enables precise temperature control within a defined area. Many thermal applications are being explored with this noninvasive, nonionizing technology, such as hyperthermia generation, to release drugs from thermosensitive liposomal carriers. These drugs can include chemotherapies such as doxorubicin, for which targeted release is desired due to the dose-limiting systemic side effects, namely cardiotoxicity. Doxorubicin is a mainstay for treating a variety of malignant tumors and is commonly used in relapsed or recurrent rhabdomyosarcoma (RMS). RMS is the most common solid soft tissue extracranial tumor in children and young adults. Despite aggressive, multimodal therapy, RMS survival rates have remained the same for the past 30 years. To explore a solution for addressing this unmet need, an experimental protocol was developed to evaluate the release of thermosensitive liposomal doxorubicin (TLD) in an immunocompetent, syngeneic RMS mouse model using MRgHIFU as the source of hyperthermia for drug release.

Presented here is a protocol to use controlled hyperthermia, generated by magnetic resonance-guided high intensity focused ultrasound, to trigger drug release from temperature-sensitive liposomes in a rhabdomyosarcoma mouse model.

Magnetic resonance-guided high intensity focused ultrasound (MRgHIFU) is an established method for producing localized hyperthermia. Given the real-time ...

Cancer Research

Magnetic-, Acoustic-, and Optical-Triple-Responsive Microbubbles for Magnetic Hyperthermia and Pothotothermal Combination Cancer Therapy

The precision delivery of anti-cancer agents which aim for targeted and deep-penetrated delivery as well as a controlled release at the tumor site has been challenged. Here, we fabricate iron oxide nanoparticle shelled microbubbles (NSMs) through self-assembly, synergizing magnetic, acoustic, and optical responsiveness in one nanotherapeutic platform. Iron oxide nanoparticles serve as both magnetic and photothermal agents. Once intravenously injected, NSMs can be magnetically guided to the tumor site. Ultrasound triggers the release of iron oxide nanoparticles, facilitating the penetration of nanoparticles deep into the tumor due to the cavitation effect of microbubbles. Thereafter, magnetic hyperthermia and photothermal therapy can be performed on the tumor for combinational cancer therapy, a solution for cancer resistance due to the tumor heterogeneity. In this protocol, the synthesis and characterization of NSMs including structural, chemical, magnetic and acoustic properties were performed. In addition, the anti-cancer efficacy by thermal therapy was investigated using in vitro cell cultures. The proposed delivery strategy and combination therapy holds great promise in cancer treatment to improve both delivery and anticancer efficacies.

Presented here is a protocol for the fabrication of iron oxide nanoparticle-shelled microbubbles (NSMs) through self-assembly, synergizing magnetic, acoustic, and optical responsiveness in one nanotherapeutic platform for magnetic hyperthermia and photothermal combination cancer therapy.

The precision delivery of anti-cancer agents which aim for targeted and deep-penetrated delivery as well as a controlled release at the tumor site has ...

Bioengineering

Simulating the Influence of a Bipolar Radiofrequency Hyperthermia System on Tumors

A Computational Modeling Approach to Investigate the Influence of Hyperthermia on the Tumor Microenvironment

The biophysical properties of the tumor microenvironment differ substantially from normal tissues. A constellation of features, including decreased vascularity, lack of lymphatic drainage, and elevated interstitial pressure, diminishes the penetration of therapeutics into tumors. Local&#160;hyperthermia within the tumor can alter microenvironmental properties, such as interstitial fluid pressure, potentially leading to improvements in drug penetration. In this context, multi-physics computational models can provide insight into the interplay between the biophysical parameters within the tumor microenvironment and can guide the design and interpretation of experiments that test the bioeffects of local hyperthermia.
This paper describes a step-by-step workflow for a computational model coupling partial differential equations describing electrical current distribution, bioheat transfer, and fluid dynamics. The main objective is to study the effects of hyperthermia delivered by a bipolar radiofrequency device on the interstitial fluid pressure within the tumor.&#160;The system of mathematical expressions linking electrical current distribution, bioheat transfer, and interstitial fluid pressure is presented, emphasizing the changes in the distribution of the interstitial fluid pressure that could be induced by the thermal intervention.

Author Spotlight: Computing the Effects of a Local Radiofrequency Hyperthermia Intervention on Tumor Biomechanics

The article describes a protocol to simulate the transient temperature profiles and the coupled spatiotemporal variation of the interstitial fluid pressure following the heating delivered by a dipolar radiofrequency hyperthermia system. The protocol can be used to assess the response of biophysical parameters characterizing the tumor microenvironment to interventional hyperthermia techniques.

The biophysical properties of the tumor microenvironment differ substantially from normal tissues. A constellation of features, including decreased ...

Cooling or Warming the Esophagus to Reduce Esophageal Injury During Left Atrial Ablation in the Treatment of Atrial Fibrillation

Ablation of the left atrium using either radiofrequency (RF) or cryothermal energy is an effective treatment for atrial fibrillation (AF) and is the most frequent type of cardiac ablation procedure performed. Although generally safe, collateral injury to surrounding structures, particularly the esophagus, remains a concern. Cooling or warming the esophagus to counteract the heat from RF ablation, or the cold from cryoablation, is a method that is used to reduce thermal esophageal injury, and there are increasing data to support this approach. This protocol describes the use of a commercially available esophageal temperature management device to cool or warm the esophagus to reduce esophageal injury during left atrial ablation. The temperature management device is powered by standard water-blanket heat exchangers, and is shaped like a standard orogastric tube placed for gastric suctioning and decompression. Water circulates through the device in a closed-loop circuit, transferring heat across the silicone walls of the device, through the esophageal wall. Placement of the device is analogous to the placement of a typical orogastric tube, and temperature is adjusted via the external heat-exchanger console.

The goal of this protocol is to describe the use of esophageal temperature modulation to counteract esophageal thermal injury from left atrial ablation for the treatment of atrial fibrillation.

Ablation of the left atrium using either radiofrequency (RF) or cryothermal energy is an effective treatment for atrial fibrillation (AF) and is the most ...

In Vitro and In Vivo Delivery of Magnetic Nanoparticle Hyperthermia Using a Custom-Built Delivery System

Hyperthermia has long been used in the treatment of cancer. Techniques have varied from the intra-tumoral insertion of hot iron rods, to systemically delivered tumor antibody-targeted magnetic nanoparticles, at temperatures from 39 &#730;C (fever-level) to 1,000 &#730;C (electrocautery) and treatment times from seconds to hours. The temperature-time relationship (thermal dose) dictates the effect with high thermal doses resulting in the tissue ablation and lower thermal doses resulting in sublethal effects such as increased blood flow, accumulation of drugs and immune stimulation. One of the most promising current medical therapies is magnetic nanoparticle hyperthermia&#160; (mNPH). This technique involves activating magnetic nanoparticles, that can be delivered systemically or intratumorally, with a non-invasive, non-toxic alternating magnetic field. The size, construct and association of the magnetic nanoparticles and the frequency and field strength of the magnetic field are major heating determinants. We have developed sophisticated instrumentation and techniques for delivering reproducible magnetic nanoparticle hyperthermia in large and small animal models and cultured cells. This approach, using continuous, real time temperature monitoring in multiple locations, allows for the delivery of well-defined thermal doses to the target tissue (tumor) or cells while limiting non-target tissue heating. Precise control and monitoring of temperature, in multiple sites, and use of the industry standard algorithm (cumulative equivalent minutes at 43 &#730;C /CEM43), allows for an accurate determination and quantification of thermal dose. Our system, which allows for a wide variety of temperatures, thermal doses, and biological effects, was developed through a combination of commercial acquisitions and inhouse engineering and biology developments. This system has been optimized in a manner that allows for the rapid conversion between ex vivo, in vitro, and in vivo techniques. The goal of this protocol is to demonstrate how to design, develop and implement an effective technique and system for delivering reproducible and accurate magnetic nanoparticle therapy (mNP) hyperthermia.

This protocol presents techniques and methodology necessary for the accurate delivery of magnetic nanoparticle hyperthermia using a sophisticated delivery and monitoring system.

Hyperthermia has long been used in the treatment of cancer. Techniques have varied from the intra-tumoral insertion of hot iron rods, to systemically ...

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.&#160;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.

This study utilized advanced informatics techniques to compare procedure duration in patients undergoing radiofrequency atrial ablation treated with active esophageal cooling to those treated with traditional luminal esophageal temperature monitoring. Contextual inquiry, workflow analysis, and data mapping were utilized. The findings demonstrated reduced procedure time and variability with active cooling.

Various methods are utilized during radiofrequency (RF) pulmonary vein isolation (PVI) for the treatment of atrial fibrillation (AF) to protect the ...

Investigation of the Electrophysiological and Thermographic Safety Parameters of Surgical Energy Devices During Thyroid and Parathyroid Surgery in a Porcine Model

In thyroid and parathyroid surgery, surgical energy devices (SEDs) provide more efficient hemostasis than conventional clamp-and-tie hemostasis in areas with rich blood supply. However, when a SED is activated near the recurrent laryngeal nerve (RLN), the heat generated by the SED may injure the nerve irreversibly. To safely apply SEDs in thyroid/parathyroid surgery, this article introduces experimental porcine model studies to investigate the activation and cooling safety parameters of SEDs in standardized electrophysiological (EP) and thermographic (TG) procedures, respectively. In the EP safety parameter experiments, continuous intraoperative neuromonitoring (C-IONM) is applied to demonstrate the RLN function in real-time. The EP activation study evaluates the safe activation distance of SEDs; the EP cooling study evaluates the safe cooling time of SEDs. In the TG safety parameter experiment, a thermal imaging camera is used to record the temperature change after activating the SED. The TG activation study evaluates the lateral thermal spread distance after SED activation in a dry or humid environment and whether smoke and splashing are generated; the TG cooling study evaluates the cooling time. This will help establish the safety parameters of newly developed SEDs used in thyroid/parathyroid surgery and provide safety guidelines to avoid RLN injury and related complications.

The safe application of newly developed surgical energy devices in thyroid/parathyroid surgery attracts the attention of surgeons. Animal experimental models can avoid unnecessary trials and errors in human surgery. This report aims to demonstrate electrophysiological and thermographic methods to evaluate the safety parameters of SEDs in thyroid/parathyroid surgery.

In thyroid and parathyroid surgery, surgical energy devices (SEDs) provide more efficient hemostasis than conventional clamp-and-tie hemostasis in areas ...

Assessing Continuity Index in Pulmonary Vein Isolation with Esophageal Cooling 

Determination of Continuity Index Values in Atrial Fibrillation Ablation with Proactive Esophageal Cooling

Radiofrequency (RF) ablation to perform pulmonary vein isolation (PVI) for the treatment of atrial fibrillation involves some risk to collateral structures, including the esophagus. Proactive esophageal cooling using a dedicated device has been granted marketing authorization by the Food and Drug Administration (FDA) to reduce the risk of ablation-related esophageal injury due to RF cardiac ablation procedures, and more recent data also suggest that esophageal cooling may contribute to improved long-term efficacy of treatment. A mechanistic underpinning explaining these findings exists through the quantification of lesion placement contiguity defined as the Continuity Index (CI). Kautzner et al. quantified the CI by the order of lesion placement, such that whenever a lesion is placed non-adjacent to the prior lesion, the CI is incremented by the number of segments the catheter tip has moved over. 
To facilitate real-time calculation of the CI and encourage further adoption of this instrument, we propose a modification in which the placement of non-adjacent lesions increments the CI by only one unit, avoiding the need to count potentially nebulous markers of atrial segmentation. The objective of this protocol is to describe the methods of calculating the CI both prospectively during real-time PVI cases and retrospectively using recorded case data. A comparison of the results obtained between cases that utilized proactive esophageal cooling and cases that used luminal esophageal temperature (LET) monitoring is then provided.

Author Spotlight: Improving Lesion Contiguity in Pulmonary Vein Isolation via Proactive Esophageal Cooling

This protocol describes the methods used to determine the continuity index in patients undergoing pulmonary vein isolation procedures using radiofrequency ablation and demonstrates the differences in continuity index between ablation procedures using proactive esophageal cooling as compared to procedures using traditional luminal esophageal temperature monitoring.

Esophageal Heat Transfer for Patient Temperature Control and Targeted Temperature Management

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