DANGER CAN LURK in the most innocent warm-weather pursuits. Summer brings hot, humid weather, thunderstorms, and the potential for unexpected encounters with venomous inhabitants of the natural world. This article will review the most common summertime hazards, describe frontline emergency care interventions, and advise commonsense prevention strategies. Knowing how to avoid risk altogether is best, but when summer emergencies do occur and time is crucial, knowing how to intervene can minimize harm and even make the difference between life and death.
The heat poses risks to anyone who can't effectively cool down after exposure to high environmental temperatures. Consider the scores of deaths that result when heat waves strike across the world. Of the heat-related illnesses—heat cramps, heat syncope, heat exhaustion, and heatstroke—only heatstroke is a true medical emergency. However, less-severe forms of heat illness can be precursors to heatstroke if not appropriately treated.
Heat-related illnesses are more common when the temperature is above 95° F (35° C) and the humidity is greater than 80%.1 Other risk factors include age extremes (infants and older adults), dehydration, fatigue or sleep deprivation, obesity, cardiovascular disease, fever, muscular exertion, mental impairment, seizures, burns (including sunburn), and the use of certain drugs, including anticholinergics, beta-adrenergic blockers, angiotensin-converting enzyme inhibitors, diuretics, amphetamines, and cocaine.2
When a heatstroke victim's temperature regulatory mechanisms fail, body temperature may exceed 104° F (40° C).2 Without prompt and effective treatment, organ system failure results and the victim has a high risk of death.
Heatstroke is best differentiated from other heat-related illnesses by mental status changes that occur as a consequence of a critically elevated body temperature. Thermal injury to the brain produces anxiety, confusion, bizarre behavior, loss of coordination, hallucinations, agitation, seizures, and coma.3 Other manifestations include hypotension, tachycardia, and tachypnea. Although skin will typically be hot and dry, some heatstroke victims continue to perspire.
In the field setting, the first treatment priority is to rapidly cool the patient. Remove as much clothing as practical and place ice packs on the victim's neck, axillae, chest, abdomen, and groin. If available, use a garden hose or even a spray bottle of water to moisten the victim's skin, then use a fanning action to take full advantage of evaporative heat loss.
Another very good option is to immerse the victim in cool water to quickly reduce body temperature. The common wisdom is to avoid immersion in ice-cold water because shivering generates body heat and increases oxygen consumption. By causing subcutaneous vasoconstriction, ice water immersion may also slow heat transfer via conduction. But some evidence suggests that immersion in icy water may be safe and effective because of the beneficial effects of very rapid cooling.2,4
Because impaired consciousness threatens airway integrity, don't give anything by mouth if the victim isn't fully awake and alert. Maintain and monitor the ABCs (airway, breathing, and circulation).
Call for an ambulance right away so that the patient can be transported to the hospital quickly. At the scene, emergency medical services (EMS) personnel will administer high-concentration oxygen and establish I.V. access to infuse 0.9% sodium chloride solution for rehydration. They'll avoid Ringer's lactate because the liver can't metabolize lactate effectively when the patient is hyperthermic, worsening lactic acidosis.3
At the hospital, aggressive cooling measures—such as temperature-regulating blankets and iced gastric and peritoneal lavage—should continue until the patient's body temperature is lowered to approximately 100.4° F (38° C).2 The patient will be monitored with a continuous core temperature measuring device, such as a rectal probe or indwelling urinary catheter with a thermistor, to ensure that cooling measures don't inadvertently cause hypothermia.
If the patient starts to shiver, the healthcare provider may order diazepam (a benzodiazepine), or chlorpromazine (a neuroleptic). Once the preferred treatment for shivering, chlorpromazine has fallen out of favor because it lowers the seizure threshold, interferes with thermoregulation, and may cause many other serious adverse reactions such as hypotension.5 Also make sure benzodiazepines are available for I.V. administration in case seizures develop because, like shivering, seizures further elevate body temperature.
After the patient is stabilized, anticipate admission to an ICU for continued advanced life-support monitoring and interventions.
Preventing heat-related illnesses
Give patients this commonsense advice to prevent heat-related illnesses.
- Wear light-colored, loose clothing and a hat when you go outdoors in hot weather.
- Take time to acclimate to hot weather conditions before participating in strenuous activities. Children who participate in sports or other activities in hot weather, especially those who wear heavy uniforms such as marching band members, require special attention because they're more prone to heat-related illness than adults.6
- Assure adequate hydration and nutrition. Consume water or sports drinks frequently during activities in hot weather, even if you don't feel thirsty. But don't take salt tablets, which may irritate the stomach and cause electrolyte abnormalities.
- Take frequent rest breaks in shady or air-conditioned areas to cool down.
Although "near drowning" was once the term typically applied to an episode of drowning with survival, the American Heart Association now recommends abandoning this term. To promote uniform resuscitation language, drowning is used to describe immersion or submersion in a liquid, with or without survival.7,8
Drowning in water occurs year-round, but it's most commonly associated with summertime water sports. The latest drowning guidelines no longer classify drowning according to fresh- or saltwater aspiration. Although theoretically important, the actual clinical effects haven't been found to be significant in patient care.8
The typical drowning victim is a child or teenager. Although victims usually aspirate water into the lungs, laryngospasm or breathholding can produce asphyxiation without aspiration.8 Contaminants such as chemicals, algae, microbes, sand, and mud exacerbate lung damage and lead to pulmonary infection.1
The outcome of drowning is closely linked to the amount of time the victim was submerged, the degree of hypoxic central nervous system damage, the victim's age, the presence of coexisting illnesses or injuries, and water temperature. Hypothermia may protect cerebral tissues from hypoxic damage by reducing the cerebral metabolic rate. Survival rates are better when submersion occurs in icy cold water, particularly in children when hypothermia occurs before hypoxia.8
Children may also benefit from a more pronounced diving reflex. This physiologic response to asphyxia triggers bradycardia, a reduction in cardiac output, and vasoconstriction to reduce myocardial oxygen consumption and enhance blood flow to the heart and brain.
Events surrounding the drowning incident also play a role. Did the victim have a seizure, myocardial infarction, or stroke while in the water as a possible cause of the event? Did the victim sustain head or cervical spine trauma from diving into shallow water or bodysurfing? These circumstances complicate the rescue and influence emergency care delivery.
The immediate priority in managing a drowning incident is to reach the victim rapidly and provide ventilation.8 Ideally, a flotation device such as a raft or surfboard can be used to enable a safe rescue from the water without jeopardizing other lives.
Before making a rescue attempt, always consider your personal swimming ability as well as any environmental or natural hazards. Don't attempt a deepwater rescue if you're not a capable swimmer or if the attempt would be hazardous to you or other rescuers.
In the past, spinal immobilization was common practice for nearly all drowning victims. However, attempts to stabilize the spine under difficult conditions in the water often occurred at the expense of adequate airway management and ventilation. Current guidelines recommend spinal stabilization only for those drowning victims with injury mechanisms highly associated with spinal trauma, such as diving, bodysurfing, and use of water slides.8 The more important focus is now on effectively ventilating the patient during the rescue—an intervention highly correlated with survival.
Keep in mind that if the victim is potentially hypothermic, gentle handling is crucial to prevent ventricular fibrillation, a grave complication of having a cold, irritable heart.9
Once the victim is safely removed from the water, perform other measures, such as chest compressions if the victim is in cardiac arrest, as necessary. But don't use subdiaphragmatic abdominal thrusts (Heimlich maneuver) to clear water out of the airways. This is no longer recommended because it delays effective rescue techniques and may cause complications such as vomiting and aspiration. Rescue breathing can achieve ventilation even with water in the lungs.10 Aspirated water will be absorbed from the lungs into the general circulation.
EMS personnel will administer oxygen, endotracheally intubate the unresponsive patient, apply spinal immobilization devices if needed, and establish vascular access. At the hospital, the intubated victim will undergo continued advanced life-support care, including gastric decompression with a nasogastric or orogastric tube to prevent aspiration of gastric contents and improve ventilatory function. Abdominal distension impairs diaphragmatic excursion and inhibits ventilation.
Early on, predicting clinical outcome can be difficult. A victim who survives may experience transient or permanent neurologic damage. However, a prompt rescue and aggressive resuscitation offer the greatest probability for survival and complete recovery.
Stress water safety
Prevention is the best intervention for water-related tragedies. With that in mind, incorporate basic water safety measures into public and patient education whenever possible.
- Continuously supervise children who are in or near the water.
- Don't drink alcoholic beverages while in or around water.
- Never swim alone.
- Don't dive into shallow water or into water of unknown depth; jump in feet first.
- Maintain appropriate water rescue equipment and flotation devices, including life jackets, on boats and around water.
Lightning strikes occur year-round and kill on average 67 people each year in the United States; more than 80% of victims are male.11 Most lightning-related injuries occur in the summer when thunderstorms are common and more people are outdoors.
Besides directly striking a victim, lightning can kill by splashing or side flashing off a nearby strike area or by traveling through the ground ("step voltage"). Less than one-third of lightning victims die, but many survivors sustain permanent disabilities.11
Of the relatively few victims who suffer a cardiac arrest immediately after the strike, asystole is the typical finding. Although the intrinsic automaticity of cardiac cells may restore an organized cardiac rhythm, prolonged respiratory arrest from thoracic muscle spasm and impairment of the medullary respiratory center can cause a secondary hypoxic cardiac arrest. In this second-arrest scenario, victims suffer either asystole or ventricular fibrillation.
The explosive forces generated by a lightning strike can produce multisystem trauma, including a host of craniocerebral injuries such as intracranial hemorrhages and cerebral edema. Central nervous system effects include immediate but transient paralysis and mottling of extremities (keraunoparalysis) that can persist for minutes to hours, loss of consciousness, amnesia, confusion or disorientation, photophobia, and seizures.12 Talking on a hard-wired telephone during an electrical storm places an individual at high risk for telephone-mediated lightning injuries and carries the risk of tympanic membrane rupture, blindness, retinal detachment and cataracts, and death.13-15
Lightning also produces burn injuries, although most are superficial and heal without incident. They commonly result from superheated metal objects in contact with the victim's skin, such as a belt buckle, jewelry, or cell phone. The presence of unusual fern or treelike burn patterns on the skin, termed erythematous arborization or Lichtenberg figures, is characteristic of lightning injury.
Not all lightning effects are immediately obvious after the initial injury. Possible long-term complications include fatigue syndromes, subtle cognitive impairments, and posttraumatic stress disorder.12,16 Victims may need neurorehabilitation to promote recovery.
Victims of lightning strike aren't electrically charged and pose no danger to rescuers. However, the storm can continue to threaten everyone at the incident scene, so moving to adequate shelter is a high priority.
Initial emergency care is directed at supporting ABCs, immobilizing the spine, and providing advanced life support. Victims who show signs of life immediately after the strike have the best prognosis.
When dealing with more than one lightning-strike casualty, give priority to victims in cardiopulmonary arrest. This concept, called "reverse triage," stems from the fact that spontaneous cardiac activity often returns despite respiratory arrest from thoracic muscle spasm and paralysis of the medullary respiratory center. The goal is to prevent the second hypoxic cardiac arrest by supporting ventilation and circulation.
Begin CPR immediately and follow standard advanced cardiac life-support guidelines for defibrillation and drug therapy. Skin mottling and diminished or absent peripheral pulses may occur initially due to arterial vasospasm as a direct result of the lightning strike, but these usually resolve spontaneously in several hours. However, the survivor may still have ECG and myocardial perfusion abnormalities indicating serious myocardial injury.
In the ED, the victim will be evaluated and receive routine care for any complications. Educate the patient about possible long-term consequences and recommend a support group such as Lightning Strike and Electric Shock Survivors International.
Preventing lightning injuries
Given the very serious consequences of lightning strikes, prevention is the best management strategy. Incorporate these key messages into patient education.
- Get out of water and seek shelter whenever you hear thunder.
- Be aware that lightning can strike without warning, even when the sky is clear. Commercial lightning detectors are available to warn people of lightning potential during outdoor activities.
- Avoid standing near doorways, windows, fireplaces, or cave entrances, because these openings attract lightning. Also stay away from isolated metal sheds and avoid touching or standing near metal objects.
- Don't stand under the tallest object in the area, such as a single tree or a tower—lightning is attracted to the highest point in the area. A densely spaced stand of trees offers more protection.
- Don't stand near plumbing fixtures or use a hard-wired telephone—lightning can travel through plumbing and telephone lines. Turn off electronic equipment and appliances. Keep in mind that although cell phones don't conduct electricity through wiring, their metal components conduct electricity and can cause burns if lightning strikes.
BEE AND WASP STINGS
Reactions to another common summer hazard, bee and wasp stings, can range from local pain to life-threatening anaphylaxis. If a nest or hive is disturbed, bees and wasps may attack in a swarm, inflicting multiple stings that produce more severe reactions from the venom's cumulative effects, even in people who aren't allergic to bee stings.17
A local reaction to a bee or wasp sting consists of instant pain, followed by a wheal-and-flare reaction. Edema can extend several inches beyond the sting site and can even encompass an entire extremity.
Besides the local reaction, a host of systemic effects are possible depending upon the degree of a person's sensitivity to venom: generalized edema, nausea, vomiting, and diarrhea. Clinical signs of an allergic reaction include urticaria, pruritus, respiratory distress with bronchospasm and laryngeal edema, hypotension, loss of consciousness, cardiac dysrhythmias, and cardiac arrest.18
Removing the stinger is the first priority. The longer the stinger stays in place, the greater the venom absorption.19 Tweezers have been historically avoided because it was thought that pinching the stinger's venom sac could inject more venom, but at least one research study indicates that the most important aspect of removal is rapid removal.19 So, choose the quickest available method of stinger removal by either scraping it out with an item such as a credit card, knife blade, or needle, or use tweezers if that's all you have. Then apply an ice pack, if available, or hold the site under cold running water.
If the patient is having a mild reaction—for example, just pruritus and urticaria—initial treatment with an antihistamine may be all that's required, but you should still obtain emergency medical assistance as soon as possible in case the reaction escalates. However, if the victim experiences wheezing or facial edema and respiratory distress—signs of a severe allergic reaction—immediately administer epinephrine, if available, then call 911. As with any serious systemic reaction, assess and support the ABCs.
Many people with a history of severe allergic reactions to insect stings carry a prescribed epinephrine kit or pen. Help the patient use a personal epinephrine kit as necessary. Because absorption is more predictable, the IM route is preferable to the subcutaneous route. After reaching the hospital, the patient may be placed on continuous cardiac monitoring and receive additional doses of epinephrine 1:10,000 solution via slow I.V. push.
An antihistamine such as diphenhydramine and an H2 blocker such as cimetidine are also indicated to treat a serious reaction. In the field, oral liquid diphenhydramine may be easier for the victim to swallow than the tablet form.
If you're caring for the patient at the hospital, prepare to administer supplemental oxygen, initiate continuous cardiac and BP monitoring, ensure I.V. access, and administer crystalloid fluid (0.9% sodium chloride) for hypotension. For severe signs and symptoms, the patient may require additional doses of epinephrine in a 1:10,000 solution via slow IV push from EMS personnel or the ED team once continuous cardiac monitoring and resucitation equipment are available. Other medications to anticipate include albuterol or a similar bronchodilator to relieve bronchospasm, parenteral antihistamines and corticosteroids to attenuate the acute inflammatory and immune responses, and tapered doses of oral corticosteroids to manage or prevent delayed serum sickness or a recurrence of anaphylaxis.20
Inform people with an allergy to insect stings that subsequent allergic reactions may be more severe. Advise them to carry an epinephrine kit or pen (available by prescription) at all times and to wear a medical-alert bracelet. Also advise them to learn how to use the kit or pen before an emergency occurs. Many of these products have training devices that allow patients to simulate the correct technique for self-administering epinephrine. To help prevent bee and wasp stings, tell patients to avoid wearing perfume and dark colors when outside (wearing white is best), keep screens in windows and doors, and keep lids on trash cans.
In warm weather, snakes become more active. Most are nonvenomous, but one or more species of poisonous snake can be found in nearly every state. Snakes are most likely to bite defensively when suddenly confronted by a human at close range.
In the United States, the vast majority of snakebite emergencies are caused by snakes from the Crotalidae family (pit vipers), a group that includes rattlesnakes, copperheads, and water moccasins. Coral snakes, the other poisonous variety, are from the Elapidae family. These snakes are found mostly in the south and southwest. Due to their generally nonaggressive nature, coral snakes account for less than 1% of venomous snake bites.21
Pit vipers are best recognized by the presence of fangs and a triangular head that houses the venom glands. Some 7,000 to 8,000 snakebites are reported to poison control centers each year in the United States, but less than a half-dozen people die as a result of the bite.22 Most fatalities are young children, older adults, and victims who don't receive timely or adequate treatment. Most snakebite fatalities are associated with rattlesnake envenomation.22
The first step in treating snakebite is to determine whether the victim has been envenomated. Signs and symptoms depend on the type and amount of venom injected, the bite location, and the victim's age, size, and general health. Local manifestations include one or more puncture wounds in the skin (depending on number of fangs and number of strikes), pain, edema, and erythema or ecchymoses adjacent to the bite site. Vesicles or hemorrhagic bullae may appear. Systemic responses include a minty, rubbery, or metallic taste in the mouth; tingling or paresthesias of the scalp, face, and lips; muscle fasciculations; nausea; vomiting; hypotension; muscle weakness; seizures; and coagulopathies.22 However, some of these signs and symptoms can result from the victim's anxiety and panic about being bitten by a snake. If the bite site shows no evidence of local tissue edema or erythema within 8 hours, progression to systemic injury is less likely.
If in doubt about the victim's condition, assume the victim has been envenomated until proven otherwise. The first intervention is to move the victim to a safe place away from the snake. Have the victim remain still in a comfortable position to slow the circulation of venom. Next, before edema develops, remove any jewelry or constricting clothing.
To limit spread of the venom, splint and immobilize the affected limb and keep it below heart level, if possible. Keep the victim warm and calm. Don't offer alcohol or stimulants such as caffeinated drinks, because these accelerate the absorption of venom.23
Arrange for emergency transportation to the hospital. If transport will be delayed because the victim is in a remote location and the bite is on an extremity, consider applying a 2- to 4-cm-wide constricting band proximal to the wound to impede lymphatic flow (but not venous drainage or arterial flow). Don't apply the band as tightly as a tourniquet.
Using a constricting band is controversial because it may worsen the local necrotizing effects by holding venom in the tissues.22 This is a professional judgment call based on balancing the risk of systemic effects against the risk of limb damage. If you apply a band, assess distal circulation frequently and loosen the band if it becomes tight with the onset of edema.
Contrary to what's portrayed in the movies, don't incise and suck the wound or apply ice to it. Likewise, the effectiveness of commercial snakebite kits isn't supported by research.22
In the hospital, the snakebite victim requires supportive care, including ABC management, oxygen therapy, large-bore I.V. access infusing crystalloid fluids, cardiac and BP monitoring, pain management, tetanus prophylaxis, and wound care. Baseline diagnostic studies are indicated, including a coagulation profile, complete blood cell count, serum electrolytes, creatine kinase, blood type and screen, urinalysis, and an ECG. Obtain a careful history including a description of the snake, time of the bite, type of field care rendered, and any previous episodes of snakebites or administration of antivenin. Measure and record the circumference of the bitten extremity every 15 to 30 minutes to monitor the progression of edema.1
Because the potency of venom varies, the decision to administer antivenin as well as the amount is determined by the timing, type, and severity of the envenomation. Antivenin is most effective within 4?hours of the bite and less effective after 12 hours, but may reverse coagulopathy even beyond 24 hours.24 Contact the regional poison control center for guidance on antivenom administration and ongoing care.
Snakebite prevention is best accomplished through maintaining a keen awareness of snakes and their habits. Use extreme caution in known snake habitats: swamps, caves, rocks, ledges, tall grass, woodpiles, bushes, heavy underbrush, and crevices. When in these areas, wear boots and protective clothing, such as rugged trousers and heavy gloves. Use a walking stick or trekking poles while walking or hiking, especially on warm nights when snakes are most active. Hike with a partner, not alone. Don't place hands or feet in areas that haven't been inspected.
If you see a snake, don't handle or harass it and stay out of striking distance. Snakes are capable of envenomation at birth, so don't assume a young snake is harmless. Because of the bite reflex, even a dead or decapitated snake can inflict a bite for up to an hour after death. So, as a general rule, it's safer not to try to kill or capture the snake with the goal of bringing it to the hospital for identification. If the snake is available for transportation, don't handle it directly; carry it in a sealed container.
By being continuously aware of the environment, including the weather and other living creatures that occupy the world with us, many environmental emergencies can be avoided. But when they do happen, the right actions at the right time provide the best opportunity for survival.