Cave Rescue Presents Threat of Hypothermia

 

 
 
 

Collin Hu, EMT-E | James A. Spotila, PhD, EMT-B | From the October 2012 Issue | Friday, September 28, 2012


Preventing the onset of hypothermia is difficult when ambient conditions can’t be controlled. This is illustrated by a 2011 cave rescue in rural southwest Virginia. A man wedged in a fissure at the entrance of a cave was exposed to sub-freezing air temperatures for 12 hours until extricated. The rescue effort included up to 50 first responders from Carilion Clinic LifeGuard, which was in charge of patient care; Blacksburg Volunteer Rescue Squad; the Virginia Tech Cave Club; the Newport Volunteer Rescue Squad; the Giles County Volunteer Rescue Squad; the Newport Volunteer Fire Department and the Virginia Tech Rescue Squad.

EMTs succeeded in keeping the patient warm by using chemical heat packs, an electric blanket and hair dryer, and by keeping the patient physically active. This article summarizes this event. It also presents the physiological aspects of hypothermia, and the importance of a creative, flexible approach to complex rescue scenes in challenging environments.

Saved from the Cold
On a late winter afternoon in 2011, multiple fire, rescue and EMS units were dispatched to the edge of a farm in rural Virginia for a patient reportedly trapped at the entrance to a natural limestone cave. The 26-year-old patient had been wedged in an irregular rock fissure in a semi-standing position for more than two hours prior to 9-1-1 being called.

Initial concerns of a crush injury or related trauma were quickly replaced by fear of exposure-induced hypothermia. Though dry, the patient was clad in only a t-shirt and pants, and much of his body was in full contact with bedrock. The air temperature dropped below freezing with the onset of nightfall.

The challenge posed to the EMTs was not one of assessment, but how to keep a nearly inaccessible patient warm for a scene time that would last almost 12 hours.

After initial efforts to pull the patient free failed, rescue specialists were called in. Extricating the patient was a long process that required the removal of small protruding rock edges from the walls of the fissure using handheld percussion hammers and then extricating the patient in an upward direction.

Members of a cave rescue team worked from within the cave, below the fissure, chiseling away rock and pushing the patient upward, while a heavy tactical rescue (HTR) team above the cave entrance removed rock from around the patient’s upper torso and pulled him upwards using ropes secured to his waist.

Progress was measured in inches per hour. The patient’s body was initially pinned in several places, confining his left leg in a bent position beneath him. But as he was lifted, he became snagged by additional rock ledges that had to be removed, resulting in a repetitive cycle of chiseling and lifting that went on for hours.

The patient remained alert and oriented throughout the ordeal. EMS initially found his skin was cold and pale. He was uncomfortable, but was not showing signs of significant hypothermia. However, his condition slowly worsened, reaching a low point seven hours after becoming stuck. At his worst, still four hours before being extricated, the patient was lethargic, shivering moderately, and without radial or pedal pulses. He exhibited a Glasgow Coma Scale (GCS) score of 14, a heart rate of 90 beats per minute, respirations of 20 on ambient air, and blood pressure of 76/54.

Through creative efforts undertaken to actively warm him (see below) and after his body was steadily shifted to a more comfortable position by the rescue efforts, the patient’s condition gradually improved over the course of an hour. His color improved, he became more vibrant, and vital signs improved to GCS of 15, heart rate of 64 beats per minute and blood pressure of 115/85.

The patient was ultimately freed in stable condition after almost 11 hours stuck in the cave. His vital signs after he was placed on a backboard and in the ambulance were: heart rate 118, respirations 18, blood pressure 175/121, and skin still pale and cold. Despite an air temperature of 14° F when he was extricated at 3 a.m., his core temperature had only dropped to 96.8° F. Active warming efforts by EMTs had been successful at preventing systemic hypothermia. The patient was further assessed in the ambulance and then flown by Carilion Clinic LifeGuard to Carilion Roanoke Memorial Hospital, from which he was released the next day.

Systemic Hypothermia
Hypothermia is separated into three phases: mild, moderate and severe.(1) Mild hypothermia begins when the core body temperature, which normally varies among individuals from 98–100° F, drops below 95° F.(2)

As core temperature drops, several physiologic changes occur as the body begins to conserve and attempt to generate heat. This process occurs through activation of the sympathetic nervous system and includes shivering, hyperglycemia, tachycardia, vascular constriction and hypertension.(3)

When core body temperature drops below 89.6° F, moderate hypothermia sets in.(2) It results in significant altered mental status including hallucinations, agitation, somnolence and possible loss of pupillary reflex. Other findings include bradycardia, decreased cardiac output and hypoventilation.3 ECG abnormalities are also common, specifically a J or Osborn wave, which is specifically a distortion of early membrane repolarization and indicative of moderate hypothermia.(4)

In severe hypothermia (when body temperature drops below 82.4° F), a patient will exhibit marked stupor and all shivering will cease.(2) The patient will experience progressively worsening bradycardia, hypotension and hypoapnea, progressing to shock and multi-organ system failure.(3)

This patient exhibited signs of mild hypothermia throughout the incident. During the time when he had his lowest blood pressure readings and became increasingly lethargic, EMTs on scene were concerned about potential onset of moderate hypothermia.

Although it was not possible to quantify the patient’s temperature by direct measurement due to his confined position, his rapid recovery suggests his condition never advanced beyond the mildest stage of hypothermia.

The rates at which a patient’s core temperature drops and stages of hypothermia are experienced are highly dependent on ambient conditions. The timescale can vary from minutes (i.e., when submersed in cold water) to days (i.e., when exposed to freezing air temperatures with inadequate clothing).

During this cave rescue, onset of hypothermia was slow because the patient was dry and winds were calm, particularly due to shielding by rock formations. The bedrock he was in direct contact with initially lowered his temperature by conductive heat loss more rapidly than heat lost directly to the atmosphere. This is because the rock was colder than the afternoon air temperature. However, the rock walls eventually worked to insulate him, because the cooling of the rock surface lagged behind the plummeting temperature of the air. (Note: Had the patient been trapped inside the cave, as opposed to its entrance, the ambient temperature would have been a constant 54° F, the mean annual temperature for this location.) The patient’s large body mass of around 220 lbs. also contributed to relatively slow conductive heat loss.

Discussion
This rescue illustrates the challenges when key factors that are normally taken for granted on calls are absent, namely patient access, a stable environment and limited scene time. Unlike most situations, it wasn’t possible to remove this patient to a safe ambient setting.

Because of his confinement, it was difficult to even obtain vital signs. It wasn’t possible to establish an IV or intraosseous access, given the limited access to his extremities and because of the rigorous motions involved in the rescue. EMTs couldn’t have placed defibrillator pads on the patient had they been needed, and even oxygen by mask wasn’t feasible because of the amount of hammering around the patient’s head and the motion required of him during the effort. Keeping the patient warm, which was the primary goal of the EMTs during the rescue effort, also required flexibility and creativity.

The orientation and confinement of the patient prevented wrapping him in blankets or additional clothing. The primary effort to warm him consisted of applying 20-minute duration chemical heat packs wherever accessible, including his hips, arms and neck. The responding units quickly depleted all of their heat packs and eventually drained the storerooms of several neighboring EMS agencies, ultimately consuming about 175 packs.

Other means of warming included a propane space heater, but this couldn’t be brought close enough to be effective and posed a risk of fumes and fire to the rescuers inside the cave. An electric hair dryer borrowed from a local farmer was moderately successful at warming the air around the patient’s upper body, while an electric blanket draped over the patient’s head and shoulders helped as well.

Perhaps the most important warming was from the patient himself. During the course of the extrication, particularly the final few hours after his spirit was buoyed by the steady gains main by removing rock, the patient was very active, almost frantic, in his efforts to wiggle free and pull himself up and out with the rescuers’ assistance. Although this auto-warming helped keep hypothermia at bay, the fear was that the patient would exhaust himself or suffer further injuries and then quickly succumb to the cold. Fortunately, he was extricated in time.

Conclusion
The lesson to take away is that some calls require creative, even ingenious efforts to keep patients alive and bring them to safety. In this case, first responder thinking had to evolve quickly and then continuously adjust and seek out alternatives as the rescue effort stretched on.

When hypothermia from exposure is a risk, anything that warms without harming should be considered. Prolonged wintertime rescues like this also require special attention to scene safety to avoid cold-related injury and exhaustion of the first responders themselves.

This rescue illustrates that in addition to standard qualities of first responders, particularly diligence, selflessness, calmness and professionalism, some complex rescue scenes demand creativity and flexibility as well.

References
1. McSwain NE. “Environmental Trauma I: Heat and Cold” in PHTLS Prehospital Trauma Life Support, 6th Edition. Mosby Jems/Elsevier: St. Louis. 424–437, 2007.
2. Stephen RL. “Hypothermia and Frostbite.” Emergency Medicine. Saunders/Elsevier: Philadelphia. 1445–1450, 2008.
3. Hanania N & Zimmerman JL. Accidental hypothermia. Crit Care Clin. 1999;15(2):235–249.
4. Nolan J & Soar J. The ECG in hypothermia. Resuscitation 2005;64(2):133–134.




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Related Topics: Patient Care, Medical Emergencies, virginia tech rescue squad, virginia tech cave club, newport volunteer rescue squad, newport volunteer fire department, hypothermia, giles county volunteer rescue squad, extrication, cave rescue, carilion clinic lifeguard, blacksburg volunteer rescue squad, Jems Features

 

Collin Hu, EMT-E

Collin Hu, EMT-E, is second lieutenant in the U.S. Army, and a fourth-year medical student at the Edward Via College of Osteopathic Medicine. He is a member of the Blacksburg (Va.) Volunteer Rescue Squad.

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James A. Spotila, PhD, EMT-B

James A. Spotila, PhD, EMT-B, is associate professor of geology at Virginia Polytechnic Institute and State University and a member of the Blacksburg Volunteer Rescue Squad.

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