Pediatric Drowning Case: Favorable Neurologic Outcomes Possible With Prolonged CPR

A previously healthy 6-year-old male presented to the emergency department with a submersion injury.

Upon arrival, the patient was in cardiac arrest, had a GCS of 3, severe metabolic and respiratory acidosis, and required CPR for a total of 57 minutes prior to return of spontaneous circulation. Despite these findings, the patient had an excellent neurocognitive outcome. A review of the literature of pediatric submersion injuries was performed and showed that our case is unusual because survival after submersion injury complicated by cardiac arrest requiring more than 30 minutes of CPR is extremely rare.

Case
A 6-year-old male was found by his friends submerged in sea water. Family reported he had been submerged for about 10-15 minutes. Lifeguards brought him to shore and noted he was spontaneously breathing but unresponsive. Bag valve mask ventilation was initiated prior to EMS arrival to the scene. When EMS arrived, the patient had a pulse and was breathing spontaneously. Patient was placed on a non-rebreather mask and taken to the emergency department. In route, the patient became pulseless and apneic; initial rhythm was pulseless electrical activity. EMS began CPR, intubated the patient, and arrived at the ED after 15 minutes of CPR.

On arrival, the initial rhythm was PEA. Pediatric Advanced Life Support resuscitation was continued. Vascular access was achieved via IO. Endotracheal tube placement was confirmed. CPR was continued with a total of four rounds of epinephrine 0.01mg/kg. Finally, return of spontaneous circulation was achieved after 42 minutes in the ED. Initial vitals were BP 62/42, temperature 34.3C, HR 50, O2 saturation 95%, and GCS 3.

A point-of-care ABG revealed pH less than 6.85, PaCO2 72 mmHg, base excess –25, PaO2 158 mmHg, and HCO3 10 mmol/L (Table 1). Chest X-ray showed diffuse bilateral pulmonary interstitial and airspace infiltrates with predominantly perihilar distribution. Oxygenation to fractional oxygen ratio (PaO2/FiO2) was 158, indicating moderate acute respiratory distress syndrome (ARDS).

Ventilator settings were set and titrated according to lung protective ventilation strategies.¹ Initial ventilator settings were tidal volume of 6 ml/kg, RR 25, PEEP 10; and FiO2 of 100%. Settings were then titrated to a goal oxygen saturation of 88% to 95%. Bicarbonate pushes at 1mEq/kg were administered to correct the acidosis noted on the initial arterial blood gas. Two lactated ringer boluses at 20cc/kg were given due to hypotension, which improved blood pressure. Shortly after, the patient became hypotensive again and an epinephrine and dopamine drip were started, resolving the hypotension.

Repeat CXR showed worsening of infiltrates consistent with ARDS. Second ABG demonstrated persistent metabolic acidosis with pH of less than 6.85, but improved PaCO2 from 72 to 56. PEEP was then increased to 18 (Table 1).

The third arterial blood gas showed improved pH of 7.01, and the PaO2 decreased to 45mmHg, with the SpO2 range between 50%-80% (Table 1). On exam, an air leak was appreciated and the patient required reintubation. After successful reintubation, the air leak resolved and the SpO2 improved to 75%-85%.

The patient was clinically improving and after 3 hours in the ED was transferred to a nearby tertiary care center. The receiving hospital continued lung protective ventilation strategies and the repeat blood gas showed an improved pH of 7.20. Repeat chest X-ray showed improvement of ARDS. The patient was weaned to BiPAP on hospital day 7, high-flow nasal cannula on hospital day 10, and on hospital day 14 the patient was stable on room air and no longer required any oxygen support. At a 2-year follow-up, the parents reported that the patient made a complete neurologic recovery and continued to be a straight-A student.

Table 1: Arterial blood gas

Discussion
Drowning is defined as respiratory impairment secondary to submersion or immersion in liquid.² Drowning accounts for more than 500,000 deaths per year and is one of the leading causes of death in the pediatric population.³ The most common risk factors for drowning are male sex, poverty, concomitant drug or alcohol use, history of epilepsy and dysrhythmias, and age under 14 years.² For every 1 drowning death, there are 4 non-fatal drowning victims who seek care at emergency departments in the United States.⁴ Survival is influenced by a myriad of factors such as the initial rhythm and duration of CPR, but specific differences that predict mortality and neurocognitive outcomes are difficult to characterize.⁵ Unfortunately, there are currently no definitive guidelines or robust clinical evidence on which to base the duration of CPR in pediatric drowning cases.

The causes of death in drowning are often multifactorial. In toddlers and younger children, drowning can occur quickly with minimal flailing or struggle. The initial mechanism is usually due to water aspiration leading to cough, possible laryngospasm, and more fluid accumulation in the lungs.⁵ This can lead to surfactant washout, atelectasis, and ventilation/perfusion mismatch, causing ARDS. It is estimated that as little as 1-2.2 mL/kg can cause significant alteration in oxygenation.⁵ There is no proven difference between saltwater or fresh water drowning in relation to pulmonary injury.⁶Cardiac arrhythmias are usually caused by hypoxia, hypothermia, electrolyte disturbances, and acidosis. Most drowning patients present in asystole and PEA arrest, but ventricular dysrhythmias have been reported.^4,5 Sepsis, cerebral edema, and disseminated intravascular coagulation can occur within the first 72 hours from the initial insult.⁷

Our case report demonstrates the effectiveness of PALS-guided resuscitation and the benefits of lung-protective ventilator strategies in the initial management of the severe drowning patient. Other reports have led to guidelines that limit resuscitation efforts based on duration of CPR, submersion times, or water temperature.⁸ The likelihood of intact neurological function after a submersion injury is multifactorial. A combination of variables, including the circumstances surrounding the submersion injury and the treatment course, affects the likelihood of intact neurological function after drowning.

The Szpilman clinical score system has been used to prognosticate the clinical outcome and course of pediatric drowning.¹As per the Szpilman classification, drownings can be classified from grades 1 to 6 (Table 2). Our patient belonged to grade 6 — a drowning complicated by cardiopulmonary arrest, which is the most severe type of drowning.

Table 2: Szpilman Clinical Score System

In a South Korean pediatric drowning study, it was shown that poor prognosis after submersion was associated with lower consciousness levels, higher Szpilman scores, greater need for intubation and mechanical ventilator support, and longer duration of oxygen therapy. Poor prognosis was also associated with lower bicarbonate levels as well as higher sodium, AST, and ALT levels.⁹

Our patient had all of the above risk factors yet had an excellent outcome. The CPR duration in out-of-hospital pediatric cardiac arrest is often limited to 30 minutes.¹⁰ However, our patient had a CPR duration of 57 minutes. The appropriate duration of CPR for pediatric out-of-hospital cardiac arrests (OHCA) remains unclear.

In a national retrospective study from Japan, it was found that prehospital EMS-initiated CPR duration for pediatric OHCAs was independently and inversely associated with 30-day favorable outcomes. The duration of prehospital EMS-initiated CPR, beyond which the chance for 30-day favorable outcomes diminished to <1%, was 42 minutes, which is much shorter than the duration of CPR administered in this case.¹¹

In a 2015 Dutch study, the authors published data on 160 pediatric drowning cases that required CPR for more than 30 minutes and followed the long-term outcomes. One of the indicators reported to measure the neurological disability was Pediatric Cerebral Performance Category (PCPC). PCPC is a score from 1-6 where higher scores indicate poor neurologic function. In 98 (61%) of these children, resuscitation was performed for more than 30 minutes; 87 (89%) of those children died, and the 11 who survived all had a PCPC score more than 4, which indicates moderate to severe neurological disability. In the 62 (39%) of children who did not require prolonged resuscitation, 17 (27%) survived, with a PCPC score less than 3 after one year; 10 (6%) had a good neurological outcome (score 1); 5 (3%) had mild neurological disability (score 2); and 2 (1%) had moderate neurological disability (score 3).¹⁰

Conclusion
Pediatric drowning complicated by cardiac arrest must be treated on a case-by-case basis, and in select patients, a duration of CPR longer than 30 minutes is clinically indicated. The patient in this case was successfully treated and had meaningful neurological recovery after prolonged CPR and judicious use of lung-protective mechanical ventilation strategies. This demonstrates that even with prolonged CPR and severe metabolic derangements, favorable neurologic outcomes are possible.

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