CLINICAL MANAGEMENT OF NEAR DROWNING PATIENTS
ON SITE AND IN THE EMERGENCY. ROOM
by
NIRU PRASAD, M.D., F.A.A.P., F.A.C.E.P.
DEPARTMENT OF EMERGENCY MEDICINE
WEST BLOOMFIELD CENTER
HENRY FORD HOSPITAL
DEPARTMENT OF AMBULATORY PEDIATRICS
ST. JOSEPH MERCY HOSPITAL
PONTIAC, MI
INTRODUCTION
Drowning is the cause of approximately 8,000 deaths per year in the United States. Two-thirds of the victims are children less than four years of age. About 80 percent of these deaths can be prevented by proper supervision since children can drown in the bath tub, swimming pool, fish tanks, hot tubs. etc. Supervised swimming events have reduced the incidence of unusual drowning. Accidental and suicidal incidence of drowning in the lake water and ocean are further precipitated by alcohol, drug abuse, and underestimation of environmental hazards.
DEFINITIONS
Drowning - drowning is defined as asphyxia and death resulting from prolonged submersion in water.
Near Drowning - the asphyxia associated with drowning is generally due to aspiration of fluid in the lungs. however, it may develop from acute laryngospasm immediately after submersion leading to acute airway obstruction and the victim has survived for a minimum of 24 hours following the accident.
Wet Drowning - further hypoxia after the initial period of laryngospasm leads to aspiration of fluids in both lungs due to relaxation of glottis leading to pulmonary edema. The rapid sequence of events after submersion hypoxia, laryngospasm. fluid aspiration, ineffective circulation, brain injury, and brain death may occur within five to ten minutes of submersion.
Fresh water drowning - the difference in pathophysiology of aspiration of fresh water (hypotonic) and salt water (hypertonic) have little clinical significance in humans because the outcome is the same. Fresh water drowning produces hemodilution and intravasculer hemolysis. Aspiration of large amounts of sea water leads to hemoconcentration and hypovolemia.
Factors predisposing the drowning event play an important role towards management of the victims. a.) Use of alcohol or other drugs. b.) Extreme fatigue. c.) Intentional hyperventilation prior to diving or swimming under shallow water may lead to a blackout spell. d.) Sudden acute illness like epilepsy or myocardial infarction. e.) Head or spinal cord injury sustained during diving or surfing accidents. f.) Venomous sting by aquatic animals. g.) Decompression illness or air embolism associated with scuba diving.
PATHOPHYSIOLOGY OF DROWNING
Two types of pathophysiology have been observed in drowning. In 10 to 20 percent of victims dry drowning occurs where acute laryngospasm results in asphyxia and the glottis relaxes only after the respiratory efforts have ceased. In these cases there is no fluid aspirated in the lungs.
Wet drowning - After an initial period of hypoxia a large amount of fluid is aspirated into the lungs leading to decrease in P02, an increase in PCO2, and a fall in blood pH. When fresh water is aspirated (22 cc/kg) the hypotonic fluid is absorbed through the pulmonary capillary membrane resulting in the wash out of the lung surfactant and alveolar collapse, intrapulmonary shunting, and hypoxia. With salt water drowning the osmotic gradient favor transudation of fluid into alveoli leading to pulmonary edema and hypoxemia. The hypertonic fluid also causes damage to pulmonary capillary membrane with leakage of plasma protein into the aveoli. The net result of drowning is ventilation perfusion mismatch. intrapulmonary shunting, and hypoxemia. The prognostic factors for survival with good neurologic function are:
a.) Duration of hypoxic episode, i.e., length of submersion and time until effective CPR is given. b.) The temperature of the water. Submersion in cold water has better prognosis since hypothermia has a protective effect on brain function.
SYMPTOMS AND SIGNS
Patients with severe near drowning may suffer frank pulmonary edema, respiratory failure, shock, anoxic encephalopathy, brain edema, and cardiac arrest. The patient may be unconscious, semiconscious. or awake. Cyanosis, trismus, apnea, tachypnea, and wheezing may be present. The presence of pink froth from the mouth and nose indicates pulmonary edema. The cardiovascular manifestations may include tachycardia, arrhythmia, hypotension, shock, and cardiac arrest.
HISTORY
Important information to obtain during the history: a.) How long the child was submerged? b.) Did the child have any spontaneous respiratory effort upon rescue? Was there a heart rate? c.) How quickly did resuscitation begin following rescue? d.) Was the child diving in shallow water? e.) Does the child have history of seizure disorder?
Management on site.
1.) Get the victim out of the water. CPR may be started while the victim is still in the water.
2.) If the victim is breathing, place him on his side. He should be able to eject water himself but must be carefully watched.
3.) If not breathing begin CPR and shout for help.
4.) Paramedics with ALS Providers should -
a.) Intubate the victim if no heart or respiration rate.
b.) Establish IV line with Ringer's lactate (warmed if available). Keep open rate.
c.) Follow the ACLS protocol regarding drug therapy.
Drowning with severe hypothermia, if heart rate is slow do not intubate since the victim might develop asystole. Start rewarming the patient.
ASSESSMENT
During the primary survey, note for presence of spontaneous respiratory effort and a heart rate even if very slow. Following rescue of drowning victim with severe hypothermia if the heart rate is present and very slow, intubation should not be attempted as it may lead to irritation of vagus nerve resulting in asystole with severe bradycardia. Some perfusion of the brain is occurring. In this case bag mask ventilation is preferred.
PREHOSPITAL MANAGEMENT
a.) Assess airway, breathing, circulation. b.) Clean the airway of obstruction. c.) Control the airway with chin lift or jaw thrust method. protect the C spine if trauma is suspected. d.) Begin mouth to mouth or mouth to mask ventilation if no breathing is present. Ventilate with bag valve mask with high flow, high concentration oxygen as soon as equipment is available. e.) Begin CPR if no heart rate is palpable. f.) Remove the wet clothing and wrap in blanket. g.) For hypothermia, wrap in dry warm blanket and initiate rewarming while enroute to the hospital. h.) Transport patient immediately to a hospital with a Pediatric Intensive Care Unit.
PARAMEDICS WITH ADVANCE LIFE SUPPORT UNIT SHOULD
a.) Intubate the child if there is no heart or respiratory rate. b.) Establish an IV line with warm Ringer's lactate. An intraosseous infusion may be used for children. c.) Follow the ACLS Drug Protocol if needed. d.) Ventilate the child with positive pressure breathing.
FURTHER TREATMENT AT SITE INCLUDES
a.) Clear the victim's mouth with a finger sweep. b.) Place the victim in the head down position to allow fluid drainage from the mouth. c.) Give oxygen in high concentration by continuos positive airway pressure. d.) Perform Heimlich maneuver if needed. After initial stabilization victims who survive can be separated into three groups.
1.) Awake victims who are neurologically responsive and who may have signs and symptoms of respiratory compromise.
2.) Children with spontaneous respirations Glasgow Coma scale of over 5.
3.) Children with Glasgow Coma scale under 4.
In general, Group l will need mild supportive care and should be observed for development of respiratory and neurologic complication. Group 2 may re3uire more intensive therapy but generally have a chance for good outcome. Group 3 have severe neurologic injury and are at high risk for death or serious neurologic impairment.
STEPS IN TREATMENT OF NEAR DROWNING
1.) Establish airway, breathing, and circulation. CPR and Advance Cardiac Life Support as soon as possible. 2.) Check for hypothermia. If present, begin rewarming. 3.) Draw blood for appropriate lab tests - complete blood count, BUN, creatinine, electrolytes, calcium, magnesium, prothrombin time, and partial thromboplastin time before starting IV line. 4.) EKG. 5.) Blood and sputum cultures. 6.) Place nasogastric tube. 7.) Obtain chest x-ray. 8.) Ventilation with positive end-expiratory pressure. 9.) Chest physical therapy and suction. 10.) Treat with B adrenergic agent and Aminophyllin. 11.) Bronchoscopy if needed for gross aspiration of particulate matter. 12.) Correct fluid and electrolyte abnormalities. 13.) Place Foley catheter if needed. 14.) Consider early transfer for intensive cerebral resuscitation. 15.) Admit to hospital for observation.
MANAGEMENT IN THE EMERGENCY ROOM
1.) Assess ventilation - give 100% oxygen. Respiratory therapy is aimed towards keeping PO2 above 80 and PCO2 below 40. Positive end-expiratory pressure or constant positive airway pressure should be considered in any child with oxygen requirement above 40% after initial stabilization. If there is any evidence that brain
edema is developing, attempt hyperventilation to maintain PCO2 25 to 35. Protect the airway from hypoxia and aspiration if the child has depressed gag reflex. The aerosolized adrenergic therapy should be tried. Aminophyllin IV should be given if there is wheezing due to aspiration of fluid into the lungs. 2.) Stabilize the C spine. 3.) Start two IV lines with Ringer's lactate or normal saline - keep open and draw appropriate aboratory studies. 4.) Assess briefly the neurological status - pupillary response to light, posture to pain or command. spontaneous respiration. 5.) Continue basic and advance life support until the victim is stable. 6.) Obtain more history. 7.) Place the patient on a cardiac monitor, obtain blood gases. 8.) Fluid therapy should be minimized at maintenance rate in order to prevent brain edema and maintain urine output l cc/kg/hr. Frequent blood count and electrolytes determinations are done to check for hyperglycemia, hypoglycemia, and the syndrome of inappropriate antidiuretic hormone excess. 9.) Avoid giving sodium bicarbonate unless there is severe metabolic acidosis. 10.) Diuretics may increase the clearance of interstitial lung water. This is very helpful if acute pulmonary edema develops. 11.) Antibiotics should be reserved for patients with highly suspected or documented infection or those submerged in contaminated water.
FURTHER MANAGEMENT
All children who survive a near drowning episode should be admitted to the hospital for further observation of delayed complications. With more seriously injured children think about multiple organ system failure, i.e., CNS, kidney. lungs, liver, etc. It is particularly important to watch for disseminated intravascular coagulation and renal failure.
Children with severe neurologic deterioration need very close observation in an Intensive Care Unit. Management of these patients include: Intracranial pressure monitoring, intubation and hyperventilation to maintain PCO2 below 30 and P02 above 80, fluid restriction, diuretics, steroids and barbiturates.
GLASGOW COMA SCALE
A full neurologic examination of patient includes level of consciousness, vital signs. pupillary function, mental status, and motor strength in all extremities. The Glasgow Coma Scale is the most widely used effective tool to determine the level of consciousness.
TEST RESPONSE SCORE Eye opening Spontaneous 4 To voice 3 To pain 2 None l
Best Verbal Response Oriented 5 Confused 4 Inappropriate 3 Garbled sound 2 None l
Best Motor Response Follows command 6 Localizes pain 5 Withdraws from pain 4 Abnormal flexion 3 Abnormal extension 2 decerebrate None l
Total point score = 3 - 15
Steps in treatment of near drowning patients with severe neurologic deficit.
Airway control with endotracheal intubation.
Hyperventilation to maintain P02 above 90 mm Hg and PCO2 24 - 30 mm Hg
Intravenous fluids with normal saline or Ringer's lactate to maintain circulation.
Elevate head of bed to 30 degrees with cervical spine control. Nasogastric tube.
Mannitol l gm/kg intravenous infusion over 15 - 20 minutes.
Intracranial pressure monitor for Glasgow Coma Scale below 7.
Prophylactic anticonvulsant Dilantin 12 mg/kg IV at rate of 25 - 50 mg/minute.
Cardiac monitor for arrythmia during infusion.
Controversial treatments. Steroids. Barbiturate Coma. Burr holes. Mannitol before herniation.
TREATMENT OF IMMERSION HYPOTHERMIA
Measure the patient's core temperature and treat hypothermia as needed. Hypothermia improves the chance of survival If the patient is in full cardiac arrest (ventricular fibrillation, pulseless, ventricular tachycardia, or asystole) use core rewarming technique since defribrillation will not be effective.
1 have summarized the treatment of hypothermia in table form.
CONDITION TEMPERATURE TREATMENT
Mild hypothermia T. above 95 degrees F. Passive rewarming stable cardio- (35 degrees C.) plus external vascular status rewarming
Moderate hypothermia T. above 90 degrees F. Active external stable cardiovascular (32 degrees C.) rewarming plus status noninvasive core Brief immersion rewarming (heated period humidified oxygen, warm IV fluids)
Severe hypothermia Unconscious T below 86-90 Active core unstable cardio- degrees F. (30-32 degrees C.) rewarming vascular status or CPR cardiac arrest Defribrillation when temperature above 95 degrees F.
The passive external rewarming consists of removing the patient from the cold environment, thoroughly drying, and protecting from further heat loss with warm blankets.
Active external rewarming involves heated bath, heated blankets, heat pads around the body.
Active core rewarming consists of warming the central circulation by warm IV fluids, heated humidified oxygen, hemodialysis, peritoneal dialysis, or cardiopulmonary bypass.
In summary. I have discussed with you the management of the near drowning victim on site and in the Emergency Room. Psychological and social support for the child and family should be available with the onset of therapy. The family should also be informed of the possibility of neurological insult and any further delayed complications if anticipated. suggestions to the parents should be made regarding effective pool barriers, proper supervision. and CPR training to prevent the incident from happening. An emphasis has been put on early aggressive prehospital management of these patients for better prognosis and survival.
BIBLIOGRAPHY
Zanga, Joseph R., Manual of Pediatric Emergencies
Wilkins, Earl W., Jr., Emergency Medicine Textbook, 1989.
Tho, Mary and Saunders, Earl E., Current Emergency Diagnosis and Treatment. 1990
Advanced Cardiac Life support Manual, 1988 Brady, Pediatric Emergencies, 1992
"Intracranial Monitoring as a Guide to Prognosis in Near Drowned Patients," Journal of Pediatrics, 1983, 102:215
"Near Drowning and Cold Water Immersion," Annals of Emergency Medicine, 1984 Martin, T. G., 13:263 - 283
"Prognostic Factors in Pediatric Cases of Drowning and Near Drowning," Orlowskij, P., JACEP 1979-8 176 - 179
Emergency Medicine Reports, May 4, 1992