EMS, Methods To Cool A Patient In The Field

Article Author:
Deena Wasserman

Article Editor:
Megan Healy

Editors In Chief:
Mitchell Farrell
Brian Froelke

Managing Editors:
Avais Raja
Orawan Chaigasame
Carrie Smith
Abdul Waheed
Khalid Alsayouri
Trevor Nezwek
Radia Jamil
Patrick Le
Anoosh Zafar Gondal
Saad Nazir
William Gossman
Hassam Zulfiqar
Hussain Sajjad
Steve Bhimji
Muhammad Hashmi
John Shell
Matthew Varacallo
Heba Mahdy
Ahmad Malik
Sarosh Vaqar
Mark Pellegrini
James Hughes
Beata Beatty
Beenish Sohail
Nazia Sadiq
Hajira Basit
Phillip Hynes

6/24/2019 11:27:55 AM


Hyperthermia is defined as a body temperature greater than 40 degrees C. Several conditions can cause hyperthermia. In sepsis, the immunologic reaction to the infection most often manifests as a fever. Some toxic ingestions and withdrawal states can cause elevated body temperature. Certain medications can cause a hyperthermic response, such as in neuroleptic malignant syndrome. The most common disease that can be treated by cooling alone is heat-related illness and heat stroke.

Heat-related illness is a spectrum of disease that occurs when the body's thermoregulatory system does not work properly. Heat exhaustion is characterized by elevated core body temperature associated with orthostatic hypotension, tachycardia, diaphoresis, and tachypnea. Heat stroke is defined as elevated core body temperature plus central nervous system involvement (delirium, decreased the level of consciousness, or ataxia). Heat-related illness most often affects athletes (exertional hyperthermia), but can also occur during the warm weather months or in locations with extreme temperatures. Patients with impaired thermoregulation (those at extremes of age, the obese or mentally ill) are at higher risk. The definitive treatment for heat-related illness is total body cooling.

Conduction and evaporation are the two modes of cooling employed in the treatment of heat-related illness. Studies have shown ice water immersion to be the most effective and most rapid. However, there are obvious barriers to performing this in an emergency department. Marathons and other athletic events that have frequent heat-related illness sometimes have this capability. Evaporation (mist and fan) is the second most rapid way to cool a patient. Ice packs to the groin, axilla, neck, and areas near other great vessels have been shown to be less effective. Cooled intravenous fluids have been studied, but there is no clear consensus regarding their benefit (preservation of neurologic function) versus potential harm (induced shivering), but they may be considered. This article will discuss the procedure for performing evaporative cooling with other adjuncts in the field.

The priority in heat-related illness is early recognition and intervention. Military and sports literature has identified 40 degrees C as the target, and the faster the target is achieved, the lower the patient mortality.[1]


Indications for cooling include any signs of heat-related illness in the presence of elevated body temperature. Previously, heat-related illness has been defined as core body temperature greater than 40 degrees C. However, any elevation above normal body temperature in a symptomatic patient is an indication to consider cooling. The objective is to rapidly decrease the temperature below 40 degrees C, with the final goal of reaching the normal range (36 degrees C to 38 degrees C). It is important to note the patient's other vital signs, as hemodynamic instability indicates severe heat stroke, in which case, rapid cooling is the most crucial intervention to stabilize the patient.[2]


The only absolute contraindication to cooling is normal or low body temperature. Hyperthermia in a patient may be a sign of sepsis, toxic ingestion, or withdrawal, or another etiology, in which case disease-specific treatment should not be overlooked. Care should be taken to prioritize the usual resuscitation and emergent management of airway, breathing, and circulation.


Several cooling methods utilize standard equipment, such as:

  • Cold saline
  • Ice packs
  • Sheets/towels

Additional equipment that may be useful includes:

  • Cooling blankets
  • Spray bottle
  • Fan
  • A pool, such as an inflatable children's pool


All of the cooling techniques described in this article can be performed by a single provider. However, additional personnel will allow for faster cooling utilizing parallel interventions.


Make sure to take the patient's vital signs and ensure no immediate airway compromise prior to cooling. The patient should be completely exposed, and intravenous (IV) access obtained.


Continuous application of cold water to the skin can be achieved by either sponging the patient or using a spray bottle. Placing a fan to blow directly on the patient, while also spraying or sponging the patient, will increase the rate of evaporation, and thereby more rapidly decrease body temperature. Another option is to submerge a sheet in cold water and then wring it out and wrap the patient in the damp sheet. This sheet can be changed and re-submerged when it is no longer cool. The downside of these methods is that they require continuous reapplication of the water and ice to maintain efficacy. [2]

Another option is to apply ice packs to the patient. The areas that are most effective in cooling core temperature are the groin, axillae, neck, and torso. Cold saline can be infused with care to monitor for resultant shivering. More frequent ice pack changes and reapplication of cold water will allow for more rapid cooling.[3]

If a pool is available, then ice water immersion should be performed. Fill the pool with water and ice. Place the patient in the pool, taking care to submerge the torso to the groin and axillae preferentially to the extremities. Frequently recheck the patient's vital signs and monitor mental status. When the temperature is below 40 degrees C, removed the patient from the pool.[4]


Overall, cooling is a benign intervention that has few complications. The patient's vital signs must be monitored closely during the cooling process. As mentioned, patients should be monitored for shivering, which will hinder cooling efforts. Critically ill patients may further decompensate during cooling. Additionally, if a patient's body temperature drops below normal (36 degrees C), they will be at risk for the sequelae of hypothermia. An important organ to monitor during the cooling process is the skin. It is susceptible to damage from prolonged exposure to ice. Covering ice packs with a towel or sheet and regularly adjusting the site of application will mitigate this risk.[5]

If the patient was submerged in ice water, make sure to continue to monitor for hypothermia, and wrap the patient in blankets so as not to leave them exposed.[6][7][8]

Clinical Significance

In managing heat-related illness and heat stroke, decreasing core body temperature is the most critical intervention. The techniques described are easy, simple, and effective ways of cooling a patient in the field. They require little training and can be performed by an individual provider. Additionally, they are applicable in many environments. Rapidly identifying patients who would benefit from this intervention is the key to effective management.

Enhancing Healthcare Team Outcomes

EMS will frequently encounter patients with hyperthermia. While cooling the patient can take place via various methods, it is vital to transport the patient to the ED ASAP. The management of hyperthermia is best done under controlled settings by an interprofessional team approach, including nurse practitioner, emergency department physician, internist, and specialty-trained nursing staff, all working collaboratively to achieve optimal patient outcomes. [Level V] If there is a delay in transport, hyperthermia can induce seizures that tend to affect outcomes adversely.

Interested in Participating?

We are looking for contributors to author, edit, and peer review our vast library of review articles and multiple choice questions. In as little as 2-3 hours you can make a significant contribution to your specialty. In return for a small amount of your time, you will receive free access to all content and you will be published as an author or editor in eBooks, apps, online CME/CE activities, and an online Learning Management System for students, teachers, and program directors that allows access to review materials in over 500 specialties.

Improve Content - Become an Author or Editor

This is an academic project designed to provide inexpensive peer-reviewed Apps, eBooks, and very soon an online CME/CE system to help students identify weaknesses and improve knowledge. We would like you to consider being an author or editor. Please click here to learn more. Thank you for you for your interest, the StatPearls Publishing Editorial Team.

EMS, Methods To Cool A Patient In The Field - Questions

Take a quiz of the questions on this article.

Take Quiz
You have a patient who needs immediate cooling. If they are all immediately available, which of the following should you use?

Click Your Answer Below

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

Sign Up
A patient has heat-related illness. To what temperature should the patient be cooled?

Click Your Answer Below

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

Sign Up
A race competitor stops in your medic tent, acting confused. Rectal temperature is found to be 41.7 C. You immediately place the patient in an ice water pool. Which of the following should you do next?

Click Your Answer Below

Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.

Sign Up

EMS, Methods To Cool A Patient In The Field - References


Simple and effective method to lower body core temperatures of hyperthermic patients., O'Connor JP,, The American journal of emergency medicine, 2017 Jun     [PubMed]
Novel application of chemical cold packs for treatment of exercise-induced hyperthermia: a randomized controlled trial., Lissoway JB,Lipman GS,Grahn DA,Cao VH,Shaheen M,Phan S,Weiss EA,Heller HC,, Wilderness & environmental medicine, 2015 Jun     [PubMed]
Effectiveness of Ice-Sheet Cooling Following Exertional Hyperthermia., Butts CL,Spisla DL,Adams JD,Smith CR,Paulsen KM,Caldwell AR,Ganio MS,McDermott BP,, Military medicine, 2017 Sep     [PubMed]
Optimizing Cold-Water Immersion for Exercise-Induced Hyperthermia: An Evidence-Based Paper., Nye EA,Edler JR,Eberman LE,Games KE,, Journal of athletic training, 2016 Jun 2     [PubMed]
Evaluation of Various Cooling Systems After Exercise-Induced Hyperthermia., Tan PM,Teo EY,Ali NB,Ang BC,Iskandar I,Law LY,Lee JK,, Journal of athletic training, 2017 Feb     [PubMed]
Gauer R,Meyers BK, Heat-Related Illnesses. American family physician. 2019 Apr 15;     [PubMed]
Bonifacio SL,McDonald SA,Chock VY,Wusthoff CJ,Hintz SR,Laptook AR,Shankara S,Van Meurs KP, Differences in patient characteristics and care practices between two trials of therapeutic hypothermia. Pediatric research. 2019 Mar 12;     [PubMed]
Young PJ,Bellomo R,Bernard GR,Niven DJ,Schortgen F,Saxena M,Beasley R,Weatherall M, Fever control in critically ill adults. An individual patient data meta-analysis of randomised controlled trials. Intensive care medicine. 2019 Apr;     [PubMed]


The intent of StatPearls is to provide practice questions and explanations to assist you in identifying and resolving knowledge deficits. These questions and explanations are not intended to be a source of the knowledge base of all of medicine, nor is it intended to be a board or certification review of EMS-Community Paramedic. The authors or editors do not warrant the information is complete or accurate. The reader is encouraged to verify each answer and explanation in several references. All drug indications and dosages should be verified before administration.

StatPearls offers the most comprehensive database of free multiple-choice questions with explanations and short review chapters ever developed. This system helps physicians, medical students, dentists, nurses, pharmacists, and allied health professionals identify education deficits and learn new concepts. StatPearls is not a board or certification review system for EMS-Community Paramedic, it is a learning system that you can use to help improve your knowledge base of medicine for life-long learning. StatPearls will help you identify your weaknesses so that when you are ready to study for a board or certification exam in EMS-Community Paramedic, you will already be prepared.

Our content is updated continuously through a multi-step peer review process that will help you be prepared and review for a thorough knowledge of EMS-Community Paramedic. When it is time for the EMS-Community Paramedic board and certification exam, you will already be ready. Besides online study quizzes, we also publish our peer-reviewed content in eBooks and mobile Apps. We also offer inexpensive CME/CE, so our content can be used to attain education credits while you study EMS-Community Paramedic.