Field Health Beat: Hypothermia

By Mary Gouchnour Hudson

ARPP field crew are susceptible to Cold Exposure, or Hypothermia, due to the environmental conditions in which we live and work. Cold, wind, and rain during both the May/June and October/November field seasons may intensify the effects of working drenched in water on the screendeck and topside during other operational activities. Cold temperatures in October/November can be especially brutal. Two-hour long dive rotations drain heat rapidly from the divers, with water temperatures averaging in the low-to-mid seventies during May/June and in the low sixties in October/November. Hypothermia may occur in 80 degree tropical waters after long dives, and it may strike hikers caught in inclement weather in mild temperatures, so the cold Aucilla River water here is a real concern.

Hypothermia occurs when the body’s regulatory mechanisms are overwhelmed, and the normal body core temp of 98.6 F begins to fall. There are three main stages : mild, moderate, and severe.

Mild Hypothermia (98.6-95 degrees F)

Signs and symptoms can include: sensation of cold, shivering, foot-stamping, urge to urinate, increased heart rate, slight incoordination of hand movements, fatigue, and mental dullness. The victim will be awake, shivering, complaining of being cold, and conversing intelligently. With slow cooling, the individual may not be aware of being cold and may not shiver, exhibiting primarily fatigue, loss of manual dexterity, decrease in mental capacity and memory, and loss of strength. Diver performance and judgement are seriously degraded. For divers this can present a direct safety hazard.

Once these symptoms are recognized by the diver or his partner, the dive should end and the appropriate supervisory personnel notified. Topsiders should take a break and warm-up. Screendeckers should also take a warm-up break; if you are pulling lone duty, then signal the divemaster to send either additional weather gear and a warm beverage or replacement personnel. Mild hypothermia is usually a non-emergency and can be treated with warm beverages, a change of clothes, and rest. If the victim does not improve within thirty minutes or seems to be getting worse, suspect moderate hypothermia and notify the divemaster and senior most qualified medical crew on site.

Moderate Hypothermia (95-90 degrees F)

Signs and symptoms can include: weakness, drowsiness, mental dullness, memory impairment, decreased or suspended shivering, increased muscle incoordination, stumbling gait, confusion, and slurred speech. The victim will be awake, but may appear confused, apathetic, uncooperative, withdrawn, and uncommunicative. At this point, a cold exposure emergency should be declared, and the divemaster on duty and senior most medically qualified crew member will coordinate emergency efforts. Crew members should stand ready to continue operations or assist with the rescue effort as directed.

Typically, passive re-warming procedures include changing from wet clothes to dry ones, warm beverages, blankets between the victim and the ground, covering the head with a warm hat or a blanket, covering the victim with blankets, and shielding from rain and/or wind. Any further rewarming procedures are generally not recommended; however, in a remote setting, the emergency directors may provide further instruction if necessary. They will then proceed with the emergency evacuation plan as they deem necessary.

Severe Hypothermia (89 degrees F and below)

Signs and symptoms can include: no shivering, paradoxical undressing, complaints of loss of vision, inability to follow commands, inability to walk, muscle rigidity, decreased blood pressure, decreased heart rate, decreased respirations, dilated pupils, unconsciousness, and the appearance of death. Rough handling or improper re-warming may cause cardiac arrest, so extreme care is needed. After passive re-warming, personnel should be prepared to initiate CPR if indicated, taking care to treat the victim gently. Emergency directors will initiate the medical emergency and evacuation plan, and personnel should stand ready to assist according to dive plan protocols.

The ARPP’s commitment to safety through education, policy, and enforcement continues to provide staff, volunteers, and visitors with the best security possible in a potentially hazardous environment. Good science, combined with dedication to safety first, allows us all to enjoy the wonders of the Aucilla River.