ADVANCED PREHOSPITAL CARE

Patients requiring continued resuscitation or those with concern for hypothermia may require more advanced prehospital care which cannot be delivered by typical bystanders such as definitive airway management, supplemental oxygen or mechanical ventilatory support, gastric decompression, or thermal insulation.11,15 Aggressive resuscitation attempts should be initiated unless clear signs of death or as limited by operational requirements. Patients have survived prolonged submersion historically, especially in the hypothermic environment.13 For this level of care, use the typical ABCDE format below.

AIRWAY

- Assess patency of the patient's airway; consider foreign bodies unique to drowning injuries such as sand or seaweed and perform finger sweep if there is a visible obstruction.
- If the patient is unconscious and unable to maintain their own airway, place the patient in the recovery position (lateral recumbent) to minimize risk of aspiration. 10-11
- In the obtunded patient, consider early intubation if an expert in airway management is available. Definitive airway is required in patients with respiratory arrest as soon as feasible. Continued use of BVM will increase risk of emesis. If a unit is trained for the capability, intubation will decrease risk of aspiration if it is available in the pre-hospital environment.
- Due to concern for increased pulmonary airway pressures required for ventilation of the drowning patient, the use of supraglottic airways (e.g., laryngeal mask airways) is discouraged and maintaining a seal may be ineffective.10

BREATHING

- Immediately perform five rescue breaths in a patient who remains unconscious and in respiratory arrest.10,18
- If the patient is breathing spontaneously, immediately apply O2 at 15 liters/min by nonrebreather as soon as possible and until discontinued by medical officer.10-11
- Consider early use of positive pressure to maintain PEEP. Aspiration can reduce surfactant and increase atelectasis.
- Avoid head down positioning or abdominal thrusts as they decrease ventilation and increase risk of vomiting, which can lead to aspiration. Heimlich maneuver is NO LONGER recommended for drowning.16,19
- Goal oxygen saturation is 92-96%: Place pulse oximeter on ear lobe or forehead for more accurate readings.20,21

CIRCULATION

- While pulses may be difficult to identify due to hypothermia or hypotension, absence of a pulse necessitates initiation of Basic Life Support/Advanced Cardiac Life Support (ACLS) protocols. See Table 2 for CPR guidance in the drowning patient.
- Most common dysrhythmias are asystole and pulseless electrical activity. Defibrillation is not indicated with these rhythms. Attempts to attach an AED should not be made if it delays or interferes with compressions and ventilation.10,11,13
- Shockable rhythms (ventricular fibrillation or ventricular tachycardia) are present in <6% of patients and have a more positive prognosis.1
- Obtain IV access when able. Intraosseous access is an acceptable alternative if unable to obtain IV access. Administering ACLS medications through the endotracheal tube is discouraged in the drowning patient.10,11
- Many drowning patients will be volume depleted intravascularly and will have volume responsive hemodynamics. In patients who are mechanically ventilated or receiving positive pressure, hypotension may be more common as increased intrathoracic pressure reduces central venous return/preload. IV crystalloid should be considered if available. In the hypothermic patients, warmed IV fluids at 43°C (109°F) should be considered.16
- Use of IV fluids must be judicious given the increased risk for noncardiogenic pulmonary edema in these patients.
- Notably, many ACLS interventions, including pacing, atropine, lidocaine, and defibrillation, are ineffective with low core body temperatures. Antiarrhythmics should be withheld for core temperatures of < 30 °C (86 °F).
- Emphasis should be placed on chest compressions and ventilations to maintain perfusion.18

DISABILITY (NEUROLOGIC)

- Initial determination of Glasgow Coma Score should be completed to guide additional resuscitative efforts.
- If circumstances surrounding the drowning are unwitnessed and loss of consciousness is persistent, consider other etiologies other than hypoxemia, such as head injury, intoxication, arterial gas embolism (AGE). This will depend on circumstances surrounding the event (e.g., scuba diver surfacing unconscious or with neuro complaint).12
- If AGE is suspected, begin notification of hyperbaric chamber team (See Appendix B).
- The following have not shown benefit in the unconscious drowning patient: hyperosmolar agents (e.g., mannitol or hypertonic saline), hyperventilation, barbiturate coma, intracranial pressure monitoring.
- Glucose – maintain between 80-140 mg/dL for ventilated patients.

ENVIRONMENT (HYPOTHERMIA MANAGEMENT)

- Keep the victim warm (use core temperature instead of infrared devices - a low range refrigerator thermometer may be necessary). Stabilize body temperature - dry and insulate the patient to prevent heat loss.11,21-22
- Mild hypothermia: 34-35°C (93.2-95°F): passive rewarming (i.e. warm blankets and environment).
- Moderate hypothermia: 30-34°C (86-93.2°F): active external rewarming will be required when available (i.e. heating blankets, radiant heat, forced hot air, warmed IV fluids at 43°C (109°F), warm water packs).
- Severe hypothermia: < 30°C (86°F): active internal rewarming will be required when available (peritoneal lavage, esophageal rewarming tubes, cardiopulmonary bypass, extracorporeal circulation); consider extracorporeal membrane oxygenation. Withhold ACLS medications until temperature >30°C (86°F).16

DISPOSITION

- Gastric decompression: Consider placement of an orogastric or nasogastric tube in the stabilized, intubated patient given the increased risk of emesis from resuscitative efforts.
- Evacuation: Evacuate if victim required resuscitation, was unresponsive in the water, or has dyspnea or other respiratory symptoms.
- Continue resuscitation and transport to higher level of care unless there are obvious signs of death.

TERMINATING RESUSCITATION EFFORTS11,19

- If the victim has been submerged for greater than 60 minutes, in-water rescue should transition to body recovery.
- In the non-hypothermic patient, resuscitation may be stopped after 30 minutes of CPR without return of spontaneous circulation.
- In the hypothermic patient, continue resuscitation until patient is rewarmed to 30-34 °C/86-93 °F, then continue CPR. Efforts may be discontinued if the patient remains asystolic for greater than 20 minutes. Lowest known documented initial temperature in patient with full neurologic recovery was 56.6°F/13.7 °C.
- Duration of submersion correlates with risk of death or severe neurologic impairment as noted:10
  - 0-5 min – 10%
  - 6-10 min – 56%
  - 11-25 min – 88%
  - >25 min – nearly 100%

Table 2. Cardiopulmonary resuscitation (CPR) in the Drowning Patient10