Infants, children, and adolescents are at higher risk for primary cold injuries due to a combination of physiologic and cognitive factors. This issue describes the workup and management of hypothermia, frostbite, and frostnip in pediatric patients. It provides guidance for prompt diagnosis, management strategies for stabilization, and recommendations for transfer when necessary. You will learn:

•  Why pediatric patients are more susceptible to cold injuries
•  How to determine the severity of hypothermia, based on the patient’s core body temperature and associated clinical findings
•  What types of thermometers are appropriate for use in patients with hypothermia, as well as temperature measurement strategies
•  When CPR should be initiated, and when it is appropriate to stop resuscitation efforts
•  When diagnostic studies are warranted, and which studies should be ordered for patients at different stages of hypothermia
•  Types of rewarming techniques, including passive and active rewarming methods
•  How to manage patients with mild, moderate, or severe hypothermia, as well as those with frostnip or frostbite
•  Indications and evidence for the use of extracorporeal membrane oxygenation

1. Abstract
2. Case Presentations
3. Introduction
4. Critical Appraisal of the Literature
5. Etiology and Pathophysiology
   1. Hypothermia
   2. Peripheral Cold Injuries
      1. Frostnip
      2. Frostbite
6. Differential Diagnosis
7. Prehospital Care
8. Emergency Department Evaluation
   1. History
   2. Physical Examination
      1. Vital Signs
      2. Other Physical Examination Findings
      3. Peripheral Cold Injuries
9. Diagnostic Studies
   1. Laboratory Studies
   2. Other Studies
10. Treatment
    1. Hypothermia
       1. Mild Hypothermia (Hypothermia Stage I)
       2. Moderate Hypothermia (Hypothermia Stages II and III)
          • Hypothermia Stage II
          • Hypothermia Stage III
       3. Severe Hypothermia (Hypothermia Stage IV)
          • Airway Management
          • Circulatory Support
          • Irrigation for Rewarming
          • Extracorporeal Membrane Oxygenation
    2. Peripheral Cold Injuries
11. Special Circumstances
    1. Afterdrop
    2. Hypothermia in the Wilderness Setting
    3. Hypothermia After Trauma
    4. Therapeutic Hypothermia in Children
12. Controversies and Cutting Edge
13. Disposition
14. Summary
15. Risk Management Pitfalls in Management of Pediatric Patients With Cold Injuries
16. Time- and Cost-Effective Strategies
17. Case Conclusions
18. Clinical Pathway for the Management of a Pediatric Patient With Hypothermia
19. Tables and Figures
    1. Table 1. Mechanisms of Heat Loss
    2. Table 2. Differential Diagnosis for Hypothermia
    3. Table 3. Staging of Hypothermia
    4. Table 4. Electrocardiogram Findings In Hypothermia
    5. Table 5. Rewarming Techniques
    6. Table 6. Indications and Contraindications for Extracorporeal Membrane Oxygenation
    7. Figure 1. Possible Electrocardiogram Changes for Patients With Hypothermia
20. References

Abstract

Hypothermia occurs when the core body temperature falls below 35ºC (95ºF) due to primary exposure (eg, environmental exposure) or secondary to other pathologies. Infants, children, and adolescents are at higher risk for primary cold injuries due to a combination of physiologic and cognitive factors, but quick rewarming and appropriate disposition can result in survival and improved neurological outcomes. Treatment for cold injuries is guided by severity and can include passive or active measures. This issue reviews the stages of hypothermia and offers recommendations for emergent management of pediatric patients with hypothermia; guidance is also provided for the identification and management of frostnip and frostbite.

Case Presentations

An EMS call comes in to your ED: “7-year-old girl drowning in a frozen lake. ETA now.” EMS personnel then rush into the trauma bay with CPR in progress. The paramedic reports that the girl had wandered away from her family, who found her 90 minutes later on the bank of a nearly frozen lake. The girl had no pulses on EMS arrival, so they started CPR and brought her straight to the ED. On examination, she is in wet clothing, has no signs of trauma, is pulseless, and has an initial rectal temperature of 23.8ºC (74.8ºF). As you prepare for intubation and continue CPR, you try to control your racing mind and prioritize. What are the best ways to rewarm this patient? What lab tests should you be ordering? Does she need ECMO?

A 17-year-old boy comes into your ED complaining of numbness and hardening of his fingers. He is a previously healthy foreign exchange student who is staying with a host family. The symptoms started yesterday after he went snow skiing for the first time. He says he wore gloves, but he was having a hard time holding the ski poles, so he took them off midway through the day. On examination, the fingertips on both of his hands are firm to the touch, have a dark discoloration, and are without sensation. The firmness and discoloration extend only to the distal interphalangeal joint in most of the fingers, but to the proximal interphalangeal joint in the middle finger of his left hand. The thumb on his right hand has a sizeable blister. As you step out of the room, you shake your head at the idea of skiing without gloves and contemplate the next steps. How do you classify the severity of his cold injuries? Does his thumb need debridement? Should you consult a hand surgeon and/or the burn center? What is the long-term prognosis for his injuries?

Introduction

Pediatric cold injuries can be generalized, as with hypothermia, or they can be localized, as with peripheral injuries. Pediatric patients are at higher risk for cold injury due to their smaller ratio of body mass to body surface area.¹ An understanding of the pathophysiology of cold exposure is necessary to identify the treatment goals for an injury. The appropriate management will vary greatly, depending on the severity of the exposure.

This issue of Pediatric Emergency Medicine Practice describes the workup and emergent management of primary hypothermia in pediatric patients. It provides guidance for prompt diagnosis and management strategies for stabilization, and recommendations for transfer to a pediatric referral center when necessary.

Critical Appraisal of the Literature

A literature search was performed in PubMed using the search terms hypothermia, extracorporeal membrane oxygenation, cold injury, and pediatrics. The search identified 16 review articles and 38 clinical trials; of the clinical trials, 31 pertained to prevention of hypothermia and induced hypothermia in neonates and preterm infants. There is a dearth of literature on the treatment of severe hypothermia in the pediatric patient. Many recommendations are extrapolated from case series and animal studies.

Risk Management Pitfalls in Management of Pediatric Patients With Cold Injuries

6. “I obtained an initial temperature but did not continuously monitor it.”

Continuous temperature monitoring will indicate whether the interventions are working or more aggressive therapy is needed. Having an appropriate probe for monitoring core body temperature is imperative; the temperature measurement method may need to be changed, based on the rewarming method being used.

7. “I was 2 boluses in before I remembered to give heated IV fluids.”

Do not forget to prewarm isotonic fluids before administering a bolus. Cold IV fluids can cancel the benefits of other rewarming therapies. If there is time, prewarm the fluids so that they are ready on the patient’s arrival.

10. “I didn’t think getting the patient to an ECMO center would make a difference.”

If you identify a patient who needs ECMO and it is not available at your center, transfer the patient as early as possible. Contacting the ECMO center yourself can help facilitate the transfer and prepare the accepting hospital’s ECMO team. As a hospital system, performing in situ simulation for a critically ill patient in need of ECMO will help prepare for the infrequent times it occurs. For high-acuity, low-frequency emergencies like this, simulation can identify process and management issues in your hospital.

Tables and Figures

References

Evidence-based medicine requires a critical appraisal of the literature based upon study methodology and number of patients. Not all references are equally robust. The findings of a large, prospective, randomized, and blinded trial should carry more weight than a case report.

To help the reader judge the strength of each reference, pertinent information about the study is included in bold type following the reference, where available. In addition, the most informative references cited in this paper, as determined by the author, are highlighted.

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