Cold Stress Injuries, Potable Water, and Water Testing

Assessing and Treating Cold Stress Exposure Injuries

• Four common types of cold stress injuries:
  • Cold shock
  • Nonfreezing injuries
  • Freezing injuries
  • Hypothermia
• "Non-freezing" and "freezing" injuries refer to localized areas of the body exposed to cold stress, potentially causing temporary impairment, permanent scarring, or loss of the affected body part.
• Whole-body cold stress can lead to hypothermia, which, if severe or untreated, can result in organ damage or death.

Cold Shock

• Not a true "shock" in the medical sense.
• May occur when personnel move from heated areas into air-conditioned spaces.
• Individuals experience rapid body heat loss due to increased sweat evaporation from wet skin and damp clothing.
• Protection measures for those entering cold rooms (walk-in freezers, cold storage boxes) include suitable clothing or limiting exposure frequency and duration.

Non-freezing Cold Injury

• Localized injuries occurring at ambient temperatures above 32° F, associated with prolonged exposure to cold water or dampness.

Trench Foot

• A non-freezing cold injury of the feet.
• Symptoms:
  • Cold
  • Numbness
  • Paresthesia
  • Itching
  • Painful weight bearing
  • Progressing to anesthesia ("walking on blocks of wood")
  • Painful blisters
  • Local hemorrhage
• Signs:
  • Pallor
  • Mottled purple coloration
  • Swelling
  • Edema
• After re-warming, sensation returns with paresthesia, pain, and increased heat sensitivity.
• Severe cases may involve blisters, circulatory compromise, local hemorrhage, and ecchymosis, potentially leading to a prolonged post-inflammatory phase with compromised blood supply.
• May result in peripheral neuropathy.

Chilblain (chilblains)

• A red or purple discoloration of the distal extremity skin (including ears and nose) occurring after exposure to cold (generally moist cold).
• Most common in young women but can occur at any age, with relapses characteristically in autumn and winter.
• May be associated with underlying connective tissue disorders (specifically lupus erythematosus).
• Symptoms:
  • Pruritic
  • Painful (especially burning) red patches on the fingers and/or toes, generally bilaterally.
  • Sunlight may aggravate the lesions.
  • Significant scarring may result.
• Primary preventive measure: keeping clothing and exposed extremities dry.

Frostbite

• Occurs at environmental temperatures below freezing.
• The extent of tissue destruction depends primarily on the environmental temperature and length of exposure.
• Symptoms include a cold or burning sensation, progressing to numbness.
• Classifications:
  • First (superficial)
  • Second (full-thickness, usually with clear blisters)
  • Third (skin and subcutaneous tissue, sometimes with hemorrhagic blisters)
  • Fourth degree (deeper structures, including tendons, muscles, and bone).
• Signs:
  • White patches
  • Diffuse redness
  • Hardening or waxy appearance of the skin
  • Mottled gray coloration
  • Tenderness
  • Diminished light touch
  • Anesthesia (no sensation)

Hypothermia

• A general cooling of the body's core temperature.
• Primary contributing factors: whole body exposure to cold temperatures, wind, wet clothing, or cold water immersion.
• Victims of severe hypothermia should be immediately evacuated to a medical treatment facility.
• Persons with those conditions should take extra precautions to wear adequate clothing and equipment, or avoid cold stress exposure entirely.

Treatment of Cold Stress Injuries

• Take standard precautions
• Remove patient from environment
• Protect injured area from further injury/exposure
• Assess patient's vital signs.
• Administer O_2
• Remove wet or restrictive clothing and all jewelry
• Assess for skin blanching, white/waxy
• Assess for loss of feeling / sensation
• Assess to ensure skin remains soft / firm
• As rewarming begins assess casualty for tingling sensation
• Assess for swelling
• Assess for blistering (Do not break blisters)
• Assess for flushing, mottling and/or cyanosis
• Splint extremity
• Cover Extremity
• Do not rub or massage area
• Do not re-expose
• Apply heat
• Do not allow patient to use extremity
• If transport is delayed:
  • Immerse effected part in warm water, 100-105 degrees F
  • Maintain water at that temp
  • Continuously stir water
  • Continue until that part is soft and color and sensation return
  • Dress the area with a dry sterile dressing
  • Protect from refreezing
  • Expect patients to complain of severe pain

Treatment of Hyperthermia

• Take standard precautions
• Remove from environment
• Remove wet clothing, cover with blanket
• Avoid rough handling of casualty
• Do not allow casualty to walk or exert energy
• Administer O_2
• Add warming blankets or additional blankets if available
• Place heat to groin, axillary and cervical areas
• Turn up heat in treatment area or transport vehicle
• Do not provide anything by mouth
• Do not massage extremities
• Monitor vital signs
• Treat for shock
• Transport

Summary and Review

Potable Water

• Drinking water must be potable and palatable.
• Ideal water temperature range for palatability: 50-60 degrees F (10-15 degrees C).
• Potable water is treated and disinfected water deemed safe to drink by Preventive Medicine personnel; it may be considered purified.
• Bases ashore and within the continental U.S. typically have access to a municipal water supply, for which the municipality is responsible.
• In the field, the HM is frequently called upon to approve field and shipboard water sources and recommend disinfection methods before water is considered safe to drink
• All water is considered unsafe until it has been tested and disinfected if necessary
• Approval of water sources should be based on a thorough surveillance of the situation, including the color, odor, and the clarity of the water; the presence of vegetation, dead animals at the water point and possible sources of pollution upstream and onboard.
• Seek out the best available water for the unit

Procedures to produce potable water

• Iodine tablets are a form of chemical disinfection for small containers like canteens or water jugs.
• Tablets are composed of an iodine compound and are available through the Federal Supply System in bottles of 50 tablets deteriorate in storage and must be steel gray.
• Tablets that are completely yellow or brown, that stick together, or crumble easily are no longer effective and must not be used.
• Water in canteens:
  • Fill the canteen with the cleanest, clearest water available.
  • Add two iodine tablets to each 1-qt canteen full of water, or four tablets to 2-qt canteens. Tincture of iodine, 2 percent, may be used in place of the tablets. Five drops of the liquid are equivalent to one iodine tablet.
  • Put the cap on the canteen. Shake the canteen to dissolve the tablets.
  • Wait 5 min. Loosen the cap slightly and tip the canteen over to allow leakage around the canteen threads.
  • Tighten the cap and wait an additional 25 min before drinking.
• Water in 5-gal containers:
  • Fill a 5-gal container with the cleanest, clearest water available
  • Dissolve 40 iodine tablets in a canteen cup full of water to disinfect any type of water. Add this solution to the 5-gal container of water and agitate the solution.
  • Place the cap on the container loosely. Wait 5 min and then agitate the container vigorously to allow leakage to rinse the threads around the neck of the can.
  • Tighten the cap and wait an additional 25 min before using the water for any purpose.
• Personal hydration systems:
  • Use four iodine tablets for 70- or 72-oz water reservoirs and six for 100- or 102-oz reservoirs.
  • Allow 30 min of contact time before drinking the water.
  • If the water to be treated is cloudy or discolored, either double the dosage or use Chlor-Floc in a separate container.
• Chlorine bleach:
  • Calcium hypochlorite is the chemical of choice for disinfection but when it is not available for disinfection of bulk supplies, commercial household chlorine bleach (unscented sodium hypochlorite) can be used in its place. Household bleach is normally a 5 percent or 50,000 mg/L chlorine solution. Add two drops of bleach per quart of water to be disinfected and let it stand for 30 min before drinking. If a dropper is not available, wet a cloth or stick with bleach and allow it to drip into the water.
  • Use four drops from a standard 10-milliliter (mL) dropper for a 70-oz reservoir, and six drops for the 100-oz reservoir. Mix the added bleach in the reservoir water and let it stand for 30 min before drinking it.
• Boiling:
  • Use only in emergencies, Boiling is an expedient means of disinfecting small quantities of water when no other means is available.
  • To be effective in killing most disease-producing organisms, the water must be held at a rolling boil for 5 min at sea level.
  • At sea level, water boils at 212 °F or 100 °C. However, the boiling temperature decreases by about 1 °F for every 500-ft increase in elevation and 1.1 °C per 1,000-ft increase.
  • To achieve the same microbiological kill at higher elevations, the water must be boiled for longer periods. Hence, the command surgeon may prescribe longer boiling times at higher altitudes and in areas where certain heat-resistant organisms are prevalent.
  • Boiled water must be kept in a covered, uncontaminated container since boiling does not impart any residual disinfectant.
  • Where Cryptosporidium parvum is suspected to be present in untreated water, boiling is the recommended emergency water treatment method because of the relative ineffectiveness of chlorine and iodine against that organism.

Non-Potable Water

• In the operational environment, water from any untreated or treated source (including bottled water) that has not been tested and determined by the appropriate medical authority to be safe for deployed personnel to drink is considered non-potable.
• Preventive Medicine personnel can recommend authorizing the use of non-potable water for showers and personal sanitation to a commander after they have evaluated the associated risk and found it to be acceptable.
• They must test the water to ensure that it meets the acceptable criteria and that it has a minimum FAC residual of 1 milligram per liter (mg/L) (or 1 part per million (ppm) after a 30-min contact time for it to be acceptable for showering and personal sanitation.
• Personnel must label non-potable water storage tanks, taps, and spigots that have been approved for showering and personal sanitation with identifying signs such as, "NONPOTABLE WATER. DO NOT DRINK," or "DISINFECTED NONPOTABLE WATER. DO NOT DRINK - APPROVED FOR SHOWERING (AND/OR PERSONAL SANITATION) ONLY," as applicable.
• Additional signs such as "USE ONLY BOTTLED WATER TO BRUSH TEETH" may also be posted as appropriate.

Water Testing

DPD (diethyl-p-phenylene diamine) Test

• The comparator gives direct readings for both chlorine and bromine.
• The chlorine and bromine comparator is read over two ranges.
  • Low range: 0.1 - 1.0 ppm chlorine or 0.2 -2.2 ppm bromine
  • High range: 2.0 - 10.0 ppm chlorine or 4.4 - 22.2 ppm bromine
• To read the test in low range place the sample test tube in a slot directly behind one of the colorless windows located on the back of the comparator and read the low-range comparison.
• To read the test sample in high range place the sample tube in one of the openings located on top of the comparator and make the reading.
• The test sample tube is moved from one position to another until a color match is made.
• A variety of DPD test kits are available and the specific manufacturer's instructions for testing should be followed.
• The following general procedure is used to obtain both FAC and TBR:
  1. Open potable water tap and let flow not less than 2 or 3 minutes.
  2. Rinse the test tube with the water to be tested.
  3. Fill test tube with sample water to the marked line (10 ml).
  4. Add one DPD No. 1 tablet, cap the test tube, and shake to dissolve.
  5. Remove the cap from the test tube and immediately compare the test sample color with the color standards in the comparator. Color matching shall be completed within 60 seconds after addition of the DPD No. 1 tablet.
  6. Record the value of the matching color standard. If the color falls between consecutive color standards, take an intermediate value. If the color is deeper than
  7. 0-ppm chlorine or 11.0-ppm bromine color standard, add an additional DPD No. I tablet to obtain a full color response. No formulation is required with the extra tablet; take a direct reading and record.

Chloramine Test

• Total residual chlorine can be determined by using a DPD No. 4 tablet.
• The use of this tablet will not differentiate the type of chlorine, but will indicate the level of total disinfectant present.
• The test procedures for chloramines (total chlorine) residual are as follows:
  1. Rinse the test tube with the test sample, then fill to the mark.
  2. Add one DPD No. 4 tablet and allow the tablet to effervesce for rapid disintegration, then cap the test tube and shake to mix.
  3. The color that results represents the total residual chlorine.
  4. When testing for halogens in the water supply, determine whether bromine or chlorine is being used and record as either bromine or chlorine following testing.
  5. Record all findings in log provided by Preventive Medicine Department (if applicable). Any abnormal findings report to PMTs or applicable higher authority.
     • Date and location of sample taken
     • Results
     • Initials of HM