Esophageal Heat Transfer for Patient Temperature Control and Targeted Temperature Management

The overall goal of this technique is to insert an esophageal temperature management device for targeted temperature management. This method provides an innovative technique for cooling and warming patients using a device that controls patient temperature directly through the esophagus. The main advantages of this device are that it is easy to use, cost-effective, safe and can be placed by most providers in the operating room, emergency department or intensive care unit.

Demonstrating our procedure will be Stephanie Slisz, our senior clinical specialist at Attune Medical. Before beginning the procedure, obtain all of the necessary equipment including a circumferential bit block, water-based lubrication packets, the appropriate heat-exchange unit, the esophageal temperature management device and securement devices. Before inserting the esophageal temperature management device, connect the device to the heat exchanger and turn the unit on.

Set the patient target temperature according to the hospital protocol and place the heat exchanger in automatic mode. Confirm that water is flowing through the esophageal temperature management device and that there are no leaks. To measure the appropriate insertion depth for the esophageal temperature management device, extend the device from the patient's lips to the earlobe and from the earlobe to the tip of the xiphoid process.

Mark the insertion depth on the device, and generously lubricate the device approximately 15 centimeters from the distal end with water-soluble lubricant. Lay the patient in the supine position as flat as tolerated and use gentle pressure posteriorly and downward through the mouth to insert the esophageal temperature management device past the oropharynx and into the esophagus. A gentle jaw thrust may be required to assist the passage of the device.

Placing the device may be challenging in patients with angioedema, with smoke inhalation or when a C-collar is present. Rotating the device during insertion, displacing the tongue with a Yankauer or using a glidescope may be helpful with difficult insertions. Advance the device with light pressure until the required length of tube has been inserted and secure the bite block in place.

The external heat exchanger must be placed in monitor only mode during the addition of the bite block. Confirm placement and secure the device according to hospital protocol taking care that the esophageal temperature management device and tube set connections are not in contact with the patient's skin. Then, use standard suction tubing to connect the central lumen to low intermittent suction to decompress the stomach.

Before beginning targeted temperature management, confirm that the external heat exchanger is set to automatic mode and the appropriate goal temperature is set according to hospital protocols. Then, initiate the shivering prophylaxis with medications as per unit protocol and use the bedside shivering assessment scale to evaluate for shivering at regular intervals or at any time temperature reduction is not proceeding as expected. Shivering is a frequent side effect of targeted temperature management, therefore it is imperative to have a plan for frequent shivering assessment and early management.

Monitor and record the water temperature hourly. If the temperature drops below 10 degrees Celsius for one hour or more when patient is at target temperature, assess for shivering and treat the patient according to hospital protocol. Periodically reposition the esophageal temperature management device in accordance with hospital protocol.

Then, if rewarming from intentional hypothermia, follow local hospital guidelines for rewarming. If rewarming from accidental hypothermia or preventing perioperative hypothermia, set a maximum rewarming rate before beginning the rewarming. If the patient is not cooling or warming as expected, confirm that the esophageal temperature management device is at the correct depth, that there's adequate water flow and that the device is cold or warm to the touch as appropriate.

Confirm that the external heat exchanger is set appropriately in automatic mode with the desired target temperature and the appropriate water temperature and that the temperature probe is intact and accurate. Check the patient for heat generation or heat loss and confirm that the environmental temperature is consistent with the temperature modulation goal. At the end of the procedure, press monitor only to stop the external heat exchanger and withdraw the device.

Disconnect the device from the tube set connections. Close the clamps if present, and dispose of the device as per institutional policy. Then, turn off the heat exchange unit.

In this representative analysis of 30 patients treated for up to 36 hours with esophageal temperature management, the average time to temperature was 2.7 hours with 96%of the temperature readings recorded during the maintenance period within plus or minus one degree Celsius of each other consistently across all protocols regardless of the target temperature. These performances remain consistent even with treatment durations longer than 72 hours. Before placing the esophageal temperature management device, it is important to ensure that the device is connected to the external heat exchanger and there is adequate water flow to the device.