How can I best support my child’s recovery?
The reason this is so critical to discuss is because drowning is one of the leading causes of death for toddlers (ages 1-4) across the world. In fact, drowning is fatal in 13% of pediatric cases and a large number of ER visits involve children who are rescued after a submission or near-drowning. More specifically, children between ages 1-4 are mostly likely to drown in swimming pools, though sometimes oceans and lakes (especially for those children who are neurodivergent). Moreover, those under age 1 are most likely to drown in a bathtub, as 84% of bathtub drownings were children under 2 years of age. Young children are at high risk because their motor, cognitive, and self-help skills are not fully developed. Though less likely overall, children between 2-5 are still susceptible to drowning in a bathtub, especially after a fall or seizure. In fact, children with epilepsy are 6x more likely to drown than those without epilepsy and a majority of those drownings occur in a bathtub.
So let’s talk about how drownings most often happen, so we can do our best to be aware and cautious in these situations. First, it is important to know that children as young as 8-10 months can climb into a bath tub by themselves. In fact, some children have drowned in bathtubs when they were full because of a power or water outage. For drownings in bathtubs specifically, the most common causes are lapses in supervision often secondary to distraction, parents getting towels/soap/other item, or in some cases parental substance use. Unfortunately, some parents may not have received proper safety education and may not be aware that children can drown so quickly or are unable to right themselves if they overturn in a tub. Drownings that occur in swimming pools largely occur during “non-swim times”, when the pool is unsupervised or adults are asleep. Most pool drowning incidents occur during the summer and at night time (i.e., up to 85% of cases).
As much as it is awful to think amount, it can be very important to understand what happens to a child’s body after a drowning. In the short term, once a child begins to aspirate liquid into their lungs, carbon dioxide retention and hypoxia can result in cardiac arrest in as little as 5 minutes. When a child is in cold water, they can struggle more to breathe and thus aspirate more quickly, resulting in cooling of their body temperature. Hypothermia slows metabolism and decreases oxygen demands, so cold water can actually be protective in this way once hypothermia sets in. Of note, hypothermia is a normal outcome of drowning, even if the child was in warm water. Additionally, for children, they tend to experience a more rapid decrease in their body temperature which allows them to survive longer periods of hypoxia. When in hypothermia, a child may enter a metabolic crisis as adrenaline and noradrenaline are suppressed in the body, which can then result in hyperglycemia (low blood sugar). The resulting metabolic disturbance can also result in hypernatremia (too much sodium in the blood) which often leads to neurological impairment. Drowning or near-drowning injuries can result in hypoxic-ischemic injury, which is when a lack of oxygen causes a lack of blood flow in the brain, resulting in brain damage. This damage is generally irreversible in children, especially for drownings that lasted 4 minutes or more.
In terms of long-term effects, sadly, some children who survive will experience seizures, autonomic instability, muscle weakness, and even paraplegia (muscle weakness or near paralysis). The parts of the brain most often affected include the basal ganglia, cortical gray matter, and the hippocampus, which most likely to affect motor and attention/memory functioning. The combination of basal ganglia and thalamic injury result in more significant cognitive and neuromotor deficits. For those who recover much of their function after a near drowning, they do tend to have residual memory, attention/executive function, and visual-perceptual deficits as well as emotional lability, though largely preserved motor function, consistent with frontal and occipital impairments and more focal vs. generalized brain damage. On the other hand, some survivors will remain comatose and unresponsive for weeks. For every child who dies from drowning, 8 children receive emergency care for nonfatal drowning, many of whom require lifelong care (i.e., at least 40%). There is a correlation between a lack of damage to the white matter and motor function preservation and as a result in some cases, there is a significant difference between motor impairment and all other functions including cognitive, perceptual and social-emotional functioning, which can result in “locked-in” state, where the child is conscious and able to perceive most everything but cannot motor their body to communicate. Locked-in syndrome is also sometimes referred to as Conrad syndrome after a young man named Conrad Tulles who is a near-drowning survivor and advocate).
Neuroimaging at the time of the injury is an important piece of determining the extent of brain damage in terms of intervention and long-term prognosis. Children often have irregular EEGs (a test measuring electrical discharges from the brain) indicative of seizures or atypical brain activity after hypoxic-ischemic brain injury. Children who suffer near drownings are likely to have gray matter injury on MRI, while white matter (faster more efficient neurons) lesions can develop up to a week later, a similar pattern to neonatal brain injuries. Those who are comatose for a period of time tend to have an MRI that reveals diffuse atrophy of the brain. MRI scans should be completed between 3 and 7 days post-injury for most accurate results, it is recommended that the child receive both DWI and TI/T2 imaging on brain MRI, so parents may want to be aware to advocate for this. An fMRI (functional MRI) can be extremely useful after brain injury- especially to detect white mater damage. When there is white matter loss, it is primarily in the motor system, while gray matter is more wide spread. More significant white matter loss is usually associated with more severe and pervasive injury.
In terms of who is most likely to have a “full” recovery (e.g., back to or close to baseline), neurological impairment is most affected by the duration of drowning, whether they required resuscitation and if it was delayed, and the temperature of the water, also vary by age/brain maturity. Brain injury and cardiac arrest were the leading cause of long-term neurological complications. Motor impairment was most common in hypoxic injury and the extent of damage was correlated with alertness at admission and whether the child recovered a pulse prior to transport to the hospital. Children that require a higher degree of care upon hospital admission were more likely to have been without a caregiver for a period of time while submerged. Other factors that led to the poorest outcomes included: being submerged longer than 5 minutes (generally biggest indicator), delay of 10 mins of more for CPR, being less than 3 years old, and a Glasgow Coma scale (measures brain injury impact) less than 5. Spontaneous movement and intact brain stem functions are a good predictor of possible complete recovery.
Neuroplasticity, or the brains ability to repair itself and create new pathways, is strongest in the initial days and weeks after brain injury. There is some newer research that have demonstrated benefit from low-dose dexamethasone on brain swelling/inflammation in rats who experienced drowning. It is important to prevent brain inflammation because neuroinflammation can result in secondary neuronal death. Dexamethasone was able to cross the blood-brain barrier and was shown to prevent and slow cell death; however, it did not completely prevent it. Secondary brain damage can be prevented or reduced by competent care in the emergency department, depending on how quickly the child can be transported and normal physiological functions are restored (e.g., need to be gradually warmed to about 90 degrees or higher) as well as avoidance of secondary complications. On the other hand, therapeutic hypothermia (controlled cooling of the body) may be protective against brain injury in terms of improving long-term neurological outcomes; however, there are some risks of cardiac side effects and efficacy has been inconsistent. Another big area of recent research is the use of stem cells. Mesenchymal stem cells (MSCs) have high immunosuppressive ability, with overall results after near-drowning being promising; however, there has been significant variability in effectiveness in terms of type of brain injury, strain of stem cells use used, dose, delivery route, and time of infusion post-injury. For some, stem cells were found to improve sensorimotor and cognitive function in those who endured a brain injury. For those who experienced a benefit, the closer to the time of injury, the better improvement, and improvements were generally observable after only 1 week and almost all experienced benefit by 3 weeks. The highest efficacy was observed when the stem cells were infused directly into brain cavity/lumbar, though more recently the research has shown good efficacy from IV administration, which is much less invasive with less potential side effects, as they are generally safe and well-tolerated. As mentioned, there is a strong correlation between drowning and hypoxic-ischemic encephalopathy, regardless of whether it is acquired (drowning) or congenital (present from birth), as the same structures within the brain are affected. The basal ganglia, thalamus, internal capsule, and cerebellum (all structures within the brain) are most often affected in those with the poorest prognosis, consistent with HIE at birth. HIE can also result in cerebral palsy, epilepsy, and cognitive deficits similar to those with who “recover” from drowning. Spastic quadriparesis is also a common outcome of near drownings, generally resembling that seen in cerebral palsy. As such, it is thought that some of the effective interventions may be similar to those born with HIE or cerebral palsy. For example, there is some recent evidence that certain medications and/or supplements that can prevent ferroptosis (a type of iron-dependent cell death) in HIE, and this intervention may be extended to those with near-drowning HIE. It has been found to be generally most effective when administered between 24 and 72 hours after the drowning injury. More specifically, there is some evidence that supports the administration of ferrostatin, deferoxamine, and metformin, as well as melatonin, coQ10, and NAC may help to prevent ferroptosis, as they are though to remove iron and serve as antioxidants, but this is still a very new area of research. Additionally, EPO (short for erythropoietin) may be able to stop both ferroptosis and apoptosis (which is the death of damaged cells) and also stimulate bone marrow to make new red blood cells, though there has been variable evidence of effectiveness, as it appears to be dose and timing dependent.
Now let’s redirect back to the positive in terms of how we can prevent a drowning from occurring. Safety education/drowning prevention and first aid training can prevent such a tragedy. One study showed that parents who received tailored safety advice from pediatricians decreased their unsafe bathing practices compared to those who only received generic safety information. Early swimming lessons, pool fencing, and pool covers have been shown to have a significant benefit in terms of preventing drownings. In the hospital, parents require objective and clear information about prognosis including possibly of Conrad syndrome and options for interventions and long-term care. Some parents expressed being offended by recommendations (e.g., withdraw nutrition, remove life support) in terms of both the actual advice and the way in which it was communicated to the family. It is very important that parents be present at the bedside of their critically ill child and be allowed to collaborate in the decision-making about treatment and care when appropriate. And finally, some overall safety advice for parents: gather everything you need prior to adding water to bath, take your infant out of the bath if you have to leave the room for any reason, and avoid phones or other distractions during bath time. Additionally, pool alarms, safety locks and other protective devices can be crucial as well. And now, we will hear more specifically about some of the latest research and preventative tools regarding water safety from two medical professionals.