Submersion injury and hypothermia — formative SAQs

SAQ 1 — Rescue-breath-first resuscitation and Szpilman severity (10 marks)

A 3-year-old is pulled from a backyard swimming pool after an unwitnessed submersion of approximately four minutes. On arrival she is unresponsive and not breathing, with frothy secretions at the mouth and a slow, weak pulse. The water was warm. A bystander has called an ambulance but has not begun resuscitation. [3] [5]

Questions

1. Outline your immediate resuscitation sequence at the scene, including the order of rescue breaths, pulse check and compressions. (5 marks) [5]

2. Stratify this child by the Szpilman drowning classification, and describe the observation strategy and the lung-injury management over the next hours. (5 marks) [3]

Model answer

Rescue-breath-first sequence (5). I open the airway with a head tilt and chin lift, or a jaw thrust if there is any suggestion of a dive or a fall that raises cervical spine injury. Because she is not breathing normally, I give five rescue breaths, each about one second with enough volume to produce gentle chest rise, before I check the pulse. The pulse check takes under ten seconds — the brachial pulse in this small child — and because she has a slow, weak pulse with poor perfusion I begin chest compressions at fifteen to two if the heart rate is under sixty beats per minute with poor perfusion, or if there is no pulse. I attach oxygen and a bag-valve-mask with a two-hand jaw-thrust seal, remove her wet clothes, dry and insulate her, handle her gently, and measure a low-reading core temperature. I do not attempt to drain water, hang her head-down, or use abdominal thrusts, because these delay ventilation and provoke vomiting. [5]

Szpilman stratification and observation (5). This child has frothy secretions, which indicates pulmonary oedema; with a slow, weak pulse she sits at Szpilman grade four (pulmonary oedema with hypotension) or grade five if she progresses to isolated respiratory arrest. Grades four and five carry mortalities of roughly fourteen per cent and a third respectively, which is far higher than the near-zero mortality of grades one and two. Her lung injury is managed with oxygen titrated up the respiratory support ladder — high-flow nasal cannula, continuous positive airway pressure, non-invasive ventilation, or intubation and lung-protective ventilation for failing gas exchange. Because the drowning lung can evolve and worsen over four to six hours, I observe her in hospital even if she improves, and I discharge only a child who is asymptomatic with normal saturations and a normal examination over a sustained period. I check the glucose, the electrolytes, and a blood gas, and I take a careful history for a channelopathy or a seizure. [3]

SAQ 2 — Hypothermic submersion cardiac arrest (10 marks)

A 6-year-old has fallen through ice into a lake and been submerged for an estimated twenty-five minutes. He is pulled out cold, pale, and pulseless. Cardiopulmonary resuscitation is in progress. On arrival in the emergency department his core temperature reads 26 degrees Celsius and the monitor shows ventricular fibrillation. Intraosseous access is in place. [6] [9]

Questions

1. Describe your rewarming strategy by Swiss stage, and state the indications for extracorporeal rewarming. (5 marks) [6] [8]

2. State the defibrillation and adrenaline rules for this hypothermic arrest, and the temperature at which resuscitation may be terminated. (5 marks) [5] [6]

Model answer

Rewarming strategy (5). This child is Swiss stage four — profound hypothermia, core below twenty-four degrees is stage four, and at 26 degrees with no vital signs he is in stage three to four (unconscious with no vital signs). I continue high-quality cardiopulmonary resuscitation, remove his wet clothes, dry and insulate him, and handle him gently to avoid precipitating ventricular fibrillation. Because he is in cardiac arrest from profound hypothermia, I escalate immediately to active internal rewarming — warmed humidified oxygen at forty-two to forty-six degrees, warmed intravenous crystalloid at approximately forty degrees, and body cavity lavage — and, crucially, I arrange extracorporeal rewarming with extracorporeal membrane oxygenation or cardiopulmonary bypass as early as the system allows, because extracorporeal rewarming is the treatment of profound hypothermic cardiac arrest and the Saczkowski 2018 meta-analysis shows meaningful survival. Passive and active external rewarming are reserved for milder stages, not for an arrested stage four patient. [6] [8]

Defibrillation, drugs and termination (5). The core is below thirty degrees, so the myocardium is refractory to defibrillation and drugs. I deliver a single shock at the standard energy for the ventricular fibrillation, and if it fails I withhold further shocks and adrenaline until the core rises above thirty degrees, because repeated shocks and drug doses below thirty degrees are ineffective and divert effort from rewarming. Once the core is above thirty degrees, I resume standard shocks and adrenaline, but I lengthen the interval between adrenaline doses because drug clearance is slowed in hypothermia. I continue resuscitation until the core reaches at least thirty-two degrees before considering termination, because the maxim holds that nobody is dead until they are warm and dead — and prolonged resuscitation of cold-water submersion can recover with good neurological outcome. [5] [9]