Thermogenesis – how the body creates heat Work-induced – includes shivering Endocrine – epi and norepi increase cell metabolism Diet induced – metabolic
treatment – remove wet clothing, passive external rewarming, avoid rough handling, active rewarming should wait until in ER, warm IV fuids rewarming shock – reflex reipheral vasodilation, cool blood and acds return from peripheral to core and further worsen core hypothermia, cold diuresis – causes volume depletion, vasoconstriction causes htn, kidneys remove excess fluid
drug metabolism reduced, drugs may remain in peripheral system, when rewarmed pt may get toxic bolus
Near drowning death within 24 hours Dry, water in mouth stimulates larygospsm
Children can live longer. Cold water – can be resucitated up to 30 min in cardiac arrest
Adult respiratory distress syndrome – ARDS fluid leaks into alveoli causing inflammation and resp failure Destruction of surfanctant, aspiration pneumonitis, pneumothorax, renal failure,
Denity or Water – 62.4 lb/ft3, air at sea level 14.7 lb/sq in one mile up 12.2 Boyle’s law – P = 1/V at constant temperature Dalton’s Law – total = sum partial pressures ex air 760torr= 21% O160 torr, 78%N593torr 1% CO2 4 torr Henry’s Law – amount of gas dissolved in liquid proportional to pressure of gas above – ex pop bottle, as we descend N disolved into tissue, if we ascend to quickly turns into bubbles
Barotrauma – “the squeeze” – indury during descent, occurs if diver can not clear middle ear Nitrogen narcosis – state of stupor caused by nitrogen effect on the brain, use helium mixed with oxygen for deep dives. Decompression illness – nitrogen bubbles “bends”, tx decompression chamber Pulmonary overpressure – lung overinflation due to rapid ascent, holding breath air expands causing destruction of alveoli. c/o substernl chest pain, resp distress.
Arteial gas emboli – pressure build up in lungs destroying alveoli can release air bubble into circulation. Neurologic deficits after rapid ascent
Pneumomediastinum – release of gas into visceral pleura and pericardial sac, decreased BP and pulse pressure, cp, irreg heart beat
High altitude illness – decress in ambient pressure causing hypoxia, sob, dizzy, confusion, malaise, anorexia, headache, sleep disturbance, respiraory distress increase with exertion. %O same, partial pressure less. Hypoxic nemtilatory response (HVR) as O decrease resp incease. Decrease in CO2 compensated for by kidneys eliminate more bicarb. Takes 4 to 7 days Cardiovascular changesincreased heart rate to deliver more O to tissues Blood changes – increased red blood cell production – blood dopping
High altitude pulmonary edema (HAPE) vascular constriction and increased pulmonary pressure leads to HAPE tx acetazolamide for diuresis and forces out bicarb
Sections Pathophysiology of Heat and Cold Disorders Heat Disorders Cold Disorders Near-Drowning and Drowning Diving Emergencies High-Altitude Illness Nuclear Radiation
Environmental Emergencies Risk Factors Age Poor General Health Fatigue Predisposing Medical Conditions Medications Homeostasis Tendency of the body to maintain a steady and normal internal environment
Pathophysiology of Heat and Cold Disorders Mechanisms of Heat Gain and Loss Thermal Gradient Wind Relative Humidity Thermogenesis Work-Induced Thermoregulatory Diet-Induced
Pathophysiology of Heat and Cold Disorders Thermolysis Conduction Convection Radiation Evaporation Respiration
Pathophysiology of Heat and Cold Disorders Thermoregulation Body Temperature Core temperature Peripheral temperature The Hypothalmus Heat Dissipation Sweating, vasodilation Heat Conservation Shivering, vasoconstriction
Pathophysiology of Heat and Cold Disorders Thermoreceptors Peripheral thermoreceptors Central thermoreceptors Metabolic Rate Basic metabolic rate Exertional metabolic rate Core temperature measurement
Heat Disorders Hyperthermia Signs of Thermolysis Diaphoresis, increased skin temperature Signs of Thermolytic Inadequacy Altered mentation or altered level of consciousness Manifestations Heat cramps Heat exhaustion Heat stroke
Heat Disorders Predisposing Factors Age of the Patient Health of the Patient Medications Diuretics, beta-blockers, psychotropics, and antihistamines Level of Acclimatization Length and Intensity of Exposure Environmental Factors
Heat Disorders Preventive Measures Maintain adequate fluid intake. Allow time for gradual acclimatization. Limit exposure to hot environments.
Role of Dehydration in Heat Disorders Close Relationship to Heat Disorders Dehydration prevents thermolysis. Signs & Symptoms Nausea, vomiting, and abdominal distress Vision disturbances, decreased urine output Poor skin turgor and signs of hypovolemic shock Treatment Oral fluids if the patient is alert and oriented IV fluids if the patient has an altered mental status or is nauseated
Fever (Pyrexia) Pyrogens Differentiating Fever from Heatstroke Cooling the Fever Patient Consider antipyretic medication. Acetaminophen or ibuprofen Avoid sponge baths.
Cold Disorders Hypothermia Mechanisms of Heat Conservation and Loss Predisposing Factors Age of the Patient Health of the Patient Medications Prolonged or Intense Exposure Coexisting Weather Conditions
Cold Disorders Preventative Measures Dress warmly and ensure plenty of rest. Eat appropriately or at regular intervals. Limit exposure to cold environments. Degrees of Hypothermia Mild Severe Compensated Hypothermia Acute, Subacute, and Chronic Exposure
Hypothermia Treatment Active Rewarming Active external rewarming Active internal rewarming Rewarming Shock Cold Diuresis
Hypothermia Resuscitation BCLS Perform pulse and respiration checks for longer periods. Administer up to 3 shocks with the AED. Follow with CPR, rewarming, and rapid transport. ACLS Intubate and administer up to 3 shocks and initial medications. Establish IV access, begin rewarming, and transport rapidly. Avoid further resuscitation until the core temperature is above 86º F.
Frostbite Superficial Frostbite Freezing of epidermal tissue Redness followed by blanching and diminshed sensation Deep Frostbite Freezing of epidermal and subcutaneous layers White, frozen appearance
Frostbite Treatment Do not thaw the affected area if there is the possibility of refreezing. Do not massage the affected area. Administer analgesia prior to thawing. Transport; rewarm by immersion only if transport is lengthy or delayed. Cover the thawed part with a loose, sterile dressing. Elevate and immobilize the thawed part. Do not puncture or drain blisters. Do not rewarm feet if walking will be required.
Trench Foot Trench Foot Occurs above freezing. Typically occurs from standing in cold water. Symptoms are similar to frostbite. Pain may be present, and blisters may form with spontaneous rewarming. Treatment: Warm, dry, and aerate the feet. Prevention is the best treatment.
Near-Drowning and Drowning Near-Drowning vs. Drowning Pathophysiology of Drowning and Near-Drowning Dry vs. Wet Drowning Fresh-Water vs. Saltwater Drowning Fresh water causes the alveoli to collapse from a lack of surfactant. Salt water causes pulmonary edema and eventual hypoxemia due to its hypertonic nature.
Near-Drowning and Drowning Factors Affecting Survival Cleanliness of Water Length of Time Submerged Victim’s Age and General Health Water Temperature Cold-water drowning. Mammalian diving reflex. The cold-water drowning patient is not dead until he is warm and dead.
Near-Drowning and Drowning Treatment for Near-Drowning Remove the patient from the water. Attempt rescue only if properly trained and equipped. Initiate ventilation while the patient is still in the water. Suspect head and neck injury if the patient experienced a fall or was diving. Place the victim on a long spine board and use c-spine precautions throughout care. Protect the patient from heat loss. Evaluate ABCs. Begin CPR and defibrillation if indicated.
Near-Drowning and Drowning Manage the airway using proper suctioning and airway adjuncts. Administer oxygen at 100% concentration. Use respiratory rewarming, if available. Establish IV of lactated Ringer’s or normal saline at 75 mL/hr. Follow ACLS protocols if the patient is normothermic. Treat hypothermic patients according to hypothermia guidelines. Adult Respiratory Distress Syndrome
Diving Emergencies Scuba The Effects of Air Pressure on Gases Boyle’s Law The volume of a gas is inversely proportional to its pressure if the temperature is kept constant. Dalton’s Law The total pressure of a mixture of gases is equal to the sum of the partial pressures of the individual gases. Henry’s Law The amount of gas dissolved in a given volume of liquid is proportional to the pressure of the gas above it.
Diving Emergencies Pathophysiology of Diving Emergencies Increased dissolution of gases during descent due to Henry’s law. Boyle’s law dictates that these gases have a smaller volume. In a controlled ascent, the process is reversed and the gases escape through respiration. A rapid ascent causes gases to come out of solution quickly, forming gas bubbles in the blood, brain, spinal cord, skin, inner ear, muscles, and joints.
Diving Emergencies Classification of Diving Emergencies Injuries on the Surface Injuries During Descent Barotrauma Injuries on the Bottom Nitrogen narcosis Injuries During Ascent Decompression illness Pulmonary overpressure and subsequent arterial gas embolism, pneumomediastinum, or pneumothorax
Diving Emergencies General Assessment of Diving Emergencies Time at Which Signs and Symptoms Appeared Type of Breathing Apparatus Used Type of Hypothermia-Protective Garment Worn Parameters of the Dive Number of dives, depth, and duration Aircraft Travel following a Dive
Diving Emergencies Factors to Assess Rate of Ascent Associated with panic forcing a rapid ascent Inexperience of the Diver Improper Functioning of Depth Gauge Previous Medical Diseases Old Injuries Previous Episodes of Decompression Illness Use of Alcohol or Medications
Pressure Disorders Decompression Illness May occur with dives of 33’ or more. Signs & Symptoms Occur within 36 hours. Joint/abdominal pain. Fatigue, paresthesias, and CNS disturbances. Treatment Recompression.
Pressure Disorders Treatment Assess ABCs and begin CPR if required. Administer high-flow oxygen and intubate if indicated. Maintain supine position. Protect the patient from heat, cold, wetness, or noxious fumes. Transport and establish IV access. Consult with medical direction regarding administration of dexamethasone, heparin, or diazepam if CNS is involved. If aeromedical evacuation is used, maintain cabin pressure at sea level or fly at the lowest possible altitude. Send diving equipment with the patient for analysis if possible.
Pressure Disorders Pulmonary Overpressure Accidents Can occur in depths as shallow as 6’. Signs & Symptoms Substernal chest pain with associated respiratory distress and diminished breath sounds Treatment Treat as a pneumothorax. Provide rest and supplemental oxygen.
Pressure Disorders Arterial Gas Embolism Signs & Symptoms Onset is within 2–10 minutes of ascent . There is dramatic onset of sharp, tearing pain. Common presentation mimics a stroke; suspect AGE in any patient with neurological deficits immediately after ascent. Treatment Assess ABCs, provide high-flow oxygen. Maintain a supine position; monitor vital signs frequently. Establish IV access and consider administering corticosteroids. Rapidly transport to a recompression chamber.
Pressure Disorders Pneumomediastinum Signs & Symptoms Substernal chest pain, irregular pulse, abnormal heart sounds, hypotension with a narrow pulse pressure, and a change in voice Treatment Provide high-flow oxygen. Establish IV access. Transport for further evaluation.
Pressure Disorders Nitrogen Narcosis Occurs during a dive. Can contribute to accidents during the dive. Signs & Symptoms Altered levels of consciousness and impaired judgment. Treatment Return to shallow depth. Use oxygen/helium mix during dive.
High-Altitude Illness Manifestation Altitudes above 8,000’ Prevention Ascend gradually. Limit exertion. Descend for sleep. Eat a high-carbohydrate diet. Medications Acetazolamide and nifedipine
High-Altitude Illness Types of High-Altitude Illness Acute Mountain Sickness Mild cases include lightheadedness, breathlessness, weakness, headache, nausea, and vomiting. Severe cases include weakness, severe vomiting, decreased urine output, shortness of breath, and an altered level of consciousness. Treatment includes halting of ascent or descent, use of acetazolamide and antinausea drugs and supplemental oxygen.
High-Altitude Illness High-Altitude Pulmonary Edema Mild symptoms include dry cough, shortness of breath, and slight crackles in the lungs. Severe cases develop cyanosis, dyspnea, frothy sputum, weakness, and possibly coma or death. Treatment includes descent and supplemental oxygen, or portable hyperbaric bag; medications such as acetazolamide, nifedipine, and lasix may be useful also.
High-Altitude Illness High-Altitude Cerebral Edema Usually occurs as progression of AMS or HAPE. Symptoms include altered mental status, ataxia, decreased level of consciousness, and coma. Treatment includes descent and supplemental oxygen, or portable hyperbaric bag.
Nuclear Radiation Personal Safety Only appropriately trained and equipped personnel should handle radiation emergencies. Basic Nuclear Physics Atoms Protons, neutrons, and electrons Isotopes and Half-Life Ionizing radiation
Nuclear Radiation Ionizing Radiation Alpha particles Beta particles Gamma rays Neutrons Effects of Radiation on the Body Detection of Radiation RAD and REM Acute and Long-Term Effects
Nuclear Radiation Principles of Safety Time Distance Shielding Clean Accidents Patient is exposed but not contaminated. Dirty Accidents Patient is contaminated by radioactive particles, liquids, gases ,or smoke.
Nuclear Radiation Management Park upwind. Look for signs of radioactive exposure. Use portable instruments to detect radioactivity. Normal emergency care principles should be applied. Externally radiated and internally contaminated patients pose little danger. Externally contaminated patients require decontamination.
Environmental Emergencies Pathophysiology of Heat and Cold Disorders Heat Disorders Cold Disorders Near-Drowning and Drowning Diving Emergencies High-Altitude Illness Nuclear Radiation