NEHA
Dangerous Underwater Breath-holding Behavior-Related Drownings in New York State1988-2011
Hello, everyone, and welcome to the presentation, "Dangerous Underwater Breath-holding Behavior-Relating Drownings in NewYorkState from 1988to 2011."
To ask questions about this presentation, please join the presenter in the Networking Lounge at the designated time listed on the agenda.
I would now like to introduce Amanda Levy, a Public Health Epidemiologist at the NewYorkCity Department of Health and Mental Hygiene, Office of Public Health Engineering.
Thank you for the introduction.
Drowning continues to be one of the leading causes of unintentional injury death in the UnitedStates.Data collected from the Centers for Disease Control, or CDC, show a clear gender, age and racial disparity.They report that nearly 80% of all drowning fatalities occur in males, and that unintentional drowning injury and associated factors are greatest among children ages zero to four and adolescents and young adults ages 15 to 24.Their findings also report greater drowning incidents among African American youth, age 15 to 19 years old, and indicate that these individuals are six times more likely to fatally drown than whites or Hispanics of the same age.
Under the NewYorkState Sanitary Code 6-1, the NewYorkState Department of Health provides regulatory guidance to County Health Department drowning investigations at permanent bathing facilities.State Health provides oversight to the NewYorkState Department of Health and Mental Hygiene Office of Public Health Engineering in their act of surveillance of unintentional drowning injury throughout the counties of Metropolitan NewYorkCity.
This figure highlights data collection estimates on fatal and non-fatal drowning incidents in NewYorkCity from 1988 to 2011.The Office of Public Health Engineering monitors all unintentional fatal and non-fatal drowning incidents reported to our offices from permitted public and private bathing facilities.In addition to incidents reported directly, we review all unintentional drowning data from the Office of Vital Statistics, the Office of the Chief Medical Examiner, and syndromic surveillance from emergency department reports.
Emergency intake codes that match the World Health Organization International Classification of Disease, or IMPULSE CONTROL DISORDERS, Codes 9 and 10 for drowning, fatal and non-fatal submersion incidents, are reported to our department on a regular basis and investigated when warranted.
The goal of the investigation process is to prevent drowning and improve prevention efforts.The more we can understand about the course of events in these deaths and injuries, the more we are able to create strategies and targeted intervention and outreach efforts to prevent these incidents from happening in the future.
In its standard Office of Public Health Engineering drowning investigation, inspectors collect data to identify the body of water or swimming pool characteristics such as dimensions and depths, weather conditions, aquatic supervision level, rescue attempts, emergency and police response, and whether or not any witnesses were present during the incident.To improve prevention efforts, it is important to understand the situations in which drownings occur and the victims' personal risk factors.
Level of supervision is one of the most important variables that we investigate as part of this risk assessment.Our inspectors conduct an extensive review of scheduling and coverage of lifeguards and aquatic staff on site during the incident.Inspectors also capture data through injuries with lifeguards, aquatic managers, witnesses and rescue victims.
Inspectors must also take into consideration the victim's personal risk factors.As previously noted, there is a prevalence of unintentional drowning injury and death among males.Age is also a factor, however.The characteristics of drowning episodes can vary greatly by age and swimming ability.Contextual factors, such as the use of a personal flotation device, alcohol and drug use, preexisting medical conditions, and overall fitness and health are all contributing factors that also must be taken into account in any drowning incident investigation.
In 2011, two drowning fatalities were reported to the Office of Public Health Engineering.Death was precipitated by hyperventilation before breath holding under water.Both victims were observed competitively exercising with one another.One victim was seen sprinting underwater for 30 meters, coming up, and repeating the circuit many times, while the other victim was observed doing pushups beside the pool.According to friends of the victims, they had been counting laps and were competing against each other to see how many laps they could swim by the end of the summer.
Both of the victims were found at the bottom of the pool with their arms crossed.Both men became unconscious underwater after performing intentional hyperventilation breath control exercises before submerging.Lifeguards at the pool facility were familiar with the victims and recognized them as accomplished swimmers.This may have given the lifeguards on duty a false sense of security about the status of the victims.A limiting factor in this type of incident is difficulty that lifeguards have in distinguishing whether a victim is actually unconscious and/or just holding his or her breath.This confusion can delay rescue attempts.
Gender and age factors of the victims in this incident were similar to other data found within U.S. Centers for Disease Control injury statistics.Both victims were in good health, strong swimmers, and said to have been training for the military.
The following figures demonstrate the physiological mechanisms of breath holding in diving.Starting with the top diagram, normal breathing, if we look at breathing, diving and the level of carbon dioxide gas dissolved in the blood and tissue in accordance with Boyle's law that there is an inverse relationship between pressure and gas, the volume of gas in the body must be compressed during descent; and the internal and ambient pressures must be essentially equal.If this equilibrium is not reached, the differences in pressure would result in barotrauma, injuries caused by increased air or water pressure, such as scuba diving, which in the thorax would cause pulmonary edema.
With normal breathing as the diver descends, we see the partial pressure of carbon dioxide gas increasing and the partial pressure of oxygen gas decreasing.The combined effect of falling oxygen levels and rising carbon dioxide produces a significant air hunger, or the need to gasp for air, which prompts the swimmer to come out of submersion.
Moving to the bottom diagram, hyperventilation, with excessive pre-dive hyperventilation, the diver's partial pressure of oxygen falls to a hypoxic level; and consciousness may be impaired or lost before significant air hunger develops and breath-holding blackout occurs.In other words, blackout from low oxygen occurs prior to the trigger level of carbon dioxide to breathe.Most important to note in this diagram is the initial depletion of the carbon dioxide reservoir due to hyperventilation.
The distinguishing characteristic of unintentional drowning deaths from incidents that present with similar clinical features is the phenomenon of hypoxic blackout.In the case of the victims from the 2011 incident, they fell unconscious underwater after performing a series of breath-holding behaviors that lead to a loss of consciousness and subsequent drowning.Cerebral hypoxia is presumably the cause of impaired consciousness in virtually every death in breath-hold diving.
There are additional processes that can make breath holding fatal, such as those individuals with a preexisting medical condition known as long QT syndrome, the heart rhythm that can potentially cause vast chaotic heartbeats.There is strong evidence linking inherited long QT syndrome with an increased risk of drowning due to fatal arrhythmias in the water.
As noted in the previous diagram, during the drowning process, breath holding is followed by a brief spasm of the vocal cords, causing asphyxiation, resulting in oxygen depletion and carbon dioxide buildup in the body.Hyperventilation prior to submersion dives reduces carbon dioxide sensitivity, allowing oxygen to be directed away from the brain and hypoxia to develop, leading to unconsciousness.This state of reduced carbon dioxide in the blood is also known as hypocarbia.
This simple pictograph illustrates how breath holding exercises are hazardous.Hyperventilation prior to breath holding underwater can lead to fainting, known as breath-hold blackout, even in healthy persons.Hyperventilation removes carbon dioxide from the blood, which results in the brain not getting the signal that it needs to breathe, resulting in fainting underwater due to lack of oxygen and resulting in unintentional drowning or injury.
The number of incidents that can be attributed to breath-holding behavior is not fully known, as these incidents are often misdiagnosed as traditional drowning.To assess the prevalence of these behaviors in NewYorkState, the NewYorkCity Department of Health, Office of Public Engineering, collaborated with the NewYorkState Department of Health to conduct a database query of all drowning incidents that occurred during 1988 to 2011 in NewYorkState Department of Health-regulated facilities.Record review included much of the same risk assessment documentation collected as part of a standard drowning investigation, such as police reports, EMS and hospital reports, medical examiners' reports, and witness and lifeguard interviews.
Through a literature review of case studies from swimming experts, researchers and nationwide programs, we generated a listing of key words and conducted a qualitative analysis in our case review.Key words were based on the prevalence of victims' behaviors based on those found from the 2011 case and were classified by the Office of Public Health Engineering with a case definition of dangerous underwater breathing behaviors or DUBBs.
Analysis of the data confirmed that 22 drowning incidents that occurred between 1988 to 2011 were likely to be a result of hypoxic blackout.Based on a detailed review of these case files, the Office of Public Health Engineering determined that 16, or 72%, of these incidents could be classified as meeting the criteria of a dangerous underwater breath-holding behavior incident.
As indicated by the map, the geographic distribution of DUBBs incidents extended across many different jurisdictions within NewYorkState.Clustering is evident within Central NewYorkState and the NewYorkCity area; however, this incidence may be due to greater detail in case reporting from these County Health Department investigations.
From the 16 DUBBs cases, there were a total of 15 drowning incidents.This was due to the 2011 fatality that included two victims.The trends observed in the NewYorkState drowning case data are consistent with other national and regional studies.Studies that examine cases where individuals lost consciousness while swimming appear to be concentrated among health males who are usually considered good, if not advanced-level, swimmers.Similar to most recorded drowning cases nationwide, the majority of persons involved in our case review were male.Swimmers' ages ranged from 7 to 47 years, with an average case age of 17 years.
Swimming ability was characterized as beginner, good, advanced or unknown, based on State Department of Health drowning investigation guidelines.Other contextual factors of the case summary include the type of swimming pool facility.Of the 16 drownings, 7 incidents occurred at outdoor facilities; 7 at indoor facilities; and 1 incident occurred in a wave pool.The remaining incident occurred in a non-regulated stream.All but one of the incidents at the regulated facilities occurred with a lifeguard on duty and involved a lifeguard rescue attempt.The exception was an incident where a member of an advanced high school swimming program was practicing hypoxic behavior at his school's private facility before hours of operation.
Three primary dangerous underwater breathing behaviors were identified as a contributing cause of unintentional drowning injury:intentional hyperventilation, static apnea, and hypoxic training.Case review of behaviors following incidents of intentional hyperventilation illustrated that these swimmers, who began intentional hyperventilation and submersion breath control exercises, were recovered sometime later submerged underwater and not moving.
Representative cases of static apnea illustrate behaviors where participation in breath-holding contests and horseplay with friends resulted in swimmers falling unconscious underwater and being resuscitated.Unintentional drowning injury from hypoxic training were illustrated by the swimmer performing breath-holding exercises in underwater lap swimming, repeatedly submerging themselves for an extended period of time until they became unconscious.
As indicated by the table, the most commonly reported DUBB behavior was static apnea.Four cases were associated with hypoxic training, three cases with intentional hyperventilation, and two fatal cases had a combination of both intentional hyperventilation and hypoxic training behaviors.
As indicated by the graph, all four of the fatalities were due to intentional hyperventilation or a combination of both intentional hyperventilation and hypoxic training behaviors.The victims in these cases were age 17 to 22 years, male, and known to be advanced to expert swimmers.
As illustrated in the incidents described previously, half of drowning fatalities occurred when descendants were engaged in a DUBB co-activity with multiple behaviors with intentional hyperventilation and hypoxic training.We learned that overall, these behaviors are concentrated among those with a higher swimming ability; and in our case study, 50% of all cases were identified as advanced level swimmers.
Targeted policy and education interventions were implemented to include injury prevention initiatives in NewYorkCity.Among these policy changes, swimming pool operators were provided with guidance on how to update written health and safety plans to include training and required signage.Research in safety communication indicates that warning signs serve a critical role in providing information, influencing behavior and serving as a reminder.
As part of our education outreach, the Office of Public Health Engineering joined with an interagency initiative to prevent the incidents of unintentional drowning and provider resources for health and recreation among the youth in NewYorkCity.
Here are a few of the 1,400 participants from the 2014, 2015, and 2016 Learn to Swim NewYorkCity program.
As part of risk messaging to reduce the prevalence of DUBBs, the Office of Public Health Engineering developed a series of signs to be posted in permanent swimming facilities.The signage was field tested through focus groups in outreach with children and adolescents participating in YMCA swim programs and recreational programming throughout NewYorkCity.
Findings from the evaluation indicated that across all swimming levels, the no-breath-holding sign was the most effective; and the pictographic was most comprehensive to children and adolescents.
I would like to thank the following individuals for their work and support with this important research.
For more information about our water safety programs and NewYorkCity DUBBs signage requirements, please visit the following websites.
In closing, most literature does not mention these behaviors as activities to discuss as part of drowning prevention.I would like to thank those that have viewed this presentation and encourage viewers to continue to create a discussion around this important recreational health and safety topic.
Thank you.
Thank you, Amanda.
Thank you, everyone, for attending today's webinar, "Dangerous Underwater Breath-holding Behavior-Relating Drownings in NewYorkState from 1988 to 2011."On behalf of the National Environmental Health Association and our presenters, thank you for joining us today and have a great rest of your day.
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