Paradoxically, children drowning in icy cold water had better chances than those having accidents in warmer months.
Compared with children who spontaneously recover their circulation within the half-hour, death or severe brain damage – in most cases, a vegetative state – is “significantly more likely” if resuscitation continues for more than 30 minutes.
The study reached its conclusions after a review of cases by pediatric intensivists and anesthesiologists from the Netherlands. In total, the drownings of 160 children were analyzed, all of which occurred outdoors between the years 1993 and 2012.
The study is the largest of its kind, say the Dutch researchers, who examined outcomes after prolonged resuscitation in children who suffered cardiac arrest with hypothermia due to drowning.
The authors – led by Dr. Joke Kieboom of the Beatrix Children’s Hospital at the University of Groningen, Netherlands – conclude:
“These findings suggest that there is no therapeutic value of restitution beyond 30 minutes for drowned children with cardiac arrest and hypothermia. Our findings challenge the current recommendation.”
Overall in the study, only 44 children (28% of the total) were still alive 1 year after their accident, which involved pure drowning because any events complicated by a traffic or boating accident, for example, were excluded from the analysis.
Of the 160 children included in the study, 98 had received prolonged resuscitation attempts lasting more than 30 minutes, and, of those children:
- 87 died (9 in 10)
- 11 survived (1 in 10) – but in a vegetative state or with severe neurological damage.
By contrast, the outcomes were good for the children who had not needed prolonged resuscitation. Of the 62 children receiving less than 30 minutes of resus, 17 survived, and the results were positive:
- Good neurological outcome in 10 children
- Mild neurological disability in 5 children
- Moderate neurological disability in 2 children.
The maximum duration of resuscitation that was associated with a good outcome was 25 minutes.
Is new guidance needed?
While the researchers call for a change to the guidance on advanced life support after drowning, they specify that this applies only to children drowning with cardiac arrest and hypothermia, and not to cases in winter months or to accidents in other “exceptional circumstances” such as involving a motor boat. More data would be needed to establish any new recommendations in these cases.
The present guidelines developed by the European Resuscitation Council to deal with cardiac arrest as a result of drowning state that advanced life support efforts by doctors and paramedics should not be stopped until “there is clear evidence that such attempts are futile” – specifying, for example, “massive traumatic injuries, rigor mortis, putrefaction, etc.”
Other current guidance followed by emergency health care workers, published in the New England Journal of Medicine, also states that in cases of drowning with hypothermia, when advanced life support arrives following bystander cardiopulmonary resuscitation (CPR), it should continue until the patient is “rewarmed” and asystole (no output from the heart) has persisted for “more than 20 minutes.”
Drowning is a major cause of death
A report from the World Health Organization in 2014 states: “Drowning is a serious and neglected public health threat claiming the lives of 372,000 people a year worldwide.”
An editorial article accompanying the study paper seconds this view. It says drowning has received less attention than other matters of public health, “despite the numbers of deaths from drowning being equivalent to two thirds of global deaths from malnutrition and over one half of deaths from malaria.”
The overall outcomes after drowning – whatever the duration of resuscitation efforts – remain poor, especially because that specialist medical attention may not come quickly and may be too late anyway. The WHO report says this is because “unlike other injuries, survival is determined almost exclusively at the scene of the incident, and depends on two highly variable factors:”
- How quickly the person is removed from the water
- How swiftly proper resuscitation is performed.
Prevention, therefore, is “vital” in tackling the problem of drowning, through measures such as barriers at relevant locations, children being taught basic safety awareness and swimming, and bystanders being made aware of how to make “safe rescue” attempts.
Chances may be better for winter drowning
The authors propose that suffering a cardiac arrest in ice-cold water is likely to have a better outcome after resuscitation than if the drowning occurs in the warmer water of other seasons.
They caution, however, that the study did not gain enough data on winter drownings to draw definitive conclusions, observing just 17 children who drowned in the colder winter months.
Most drowning accidents occurred in spring, summer or fall, but there were good outcomes for:
- 5 of the 17 children drowned in winter (29%), compared with
- 12 of the 143 children drowned in the other seasons (8%).
The editorial article also picks up on the better chances in winter conditions, saying the study “identifies cooling as an important protective mechanism.” It says:
“Children were more likely to have a better outcome if the event occurred in winter, when water temperatures were 0-8 degrees C.”
The commentary cites evidence that “paradoxically, icy cold water clearly does have neuroprotective effects in adults” and notes that this new association with cold drowning in children – not found in previous studies of adults drowned in winter – may be because the cooling of children is enhanced by a larger skin area in relation to their total body volume (children have a larger surface-area-to-volume ratio).
Better chances in cold water could be skewed by shorter times spent submerged in the water compared with when drowning occurs in warmer water, caution the authors and commentators.
But the authors point out that, in their study, “the median estimated durations of submersion, however, were not different for winter and the other seasons.”
Further, the paper argues, there is a similar phenomenon observed in other resuscitation situations in icy cold conditions: “People in avalanches with cardiac arrest caused by hypothermia have a good prognosis compared with people in avalanches with cardiac arrest caused by asphyxia and subsequent hypothermia.”
Written by Markus MacGill