Friday, December 13, 2013

Drowning terminology: not what it used to be

Drowning terminology: not what it used to be
Authors: Peter Jones, Kevin Moran, Jonathon Webber
Journal: The New Zealand Medical Journal

This article is a nice and simple educational summary of the definition of drowning published in preparation for summer in New Zealand.  This topic is something that those who focus on drowning research harp on a lot, but it is for good reason.  By simplifying and standardizing the definition, we can all speak the same language, be on the same page, and work together to focus on prevention and treatment.

Jones P, Moran K, Webber J. Drowning terminology: not what it used to be. New Zeal Med J. 2013;126(1386):114-116.

Friday, September 27, 2013

Drowning resuscitation requires another state of mind

Drowning Resuscitation Requires Another State of Mind
Author: Joost Bierens, MD, PhD
Journal: Resuscitation, September 2013

Every nook and cranny of medicine has its "go to" guy/girl; for drowning resuscitation, it's Joost Bierens.  He, along with Dr. David Warner (Duke Anesthesiology) produced this Editorial in response to the previous article I reported on  by Nitta et al.  It brings up some intricacies in the data I missed while reading it myself and re-emphasizes the focus on ventilatory support in the resuscitation of a drowning victim.  The authors tease out some important details about the data, provide their thoughts for why the data showed what it did, and provide recommendations for future research.

Bierns JJ, Warner DS. Drowning resuscitation requires another state of mind.  Resuscitation. 2013 Sep 12.

Thursday, July 11, 2013

Out-of-hospital cardiac arrest due to drowning among children and adults from the Utstein Osaka Project

Out-of-hospital cardiac arrest due to drowning among children and adults from the Utstein Osaka Project
Authors: Masahiko Nitta, et al.
Journal: Resuscitation, Article in Press, 2013

This study out of Japan looked at 11 years of out of hospital cardiac arrest (OHCA) data, primarily focusing on the patients who experienced arrest secondary to drowning and who remained pulseless on EMS arrival.  Using data from a Utstein-style out of hospital cardiac arrest database, the authors compared outcomes between the following three groups: younger children (0-4 years), older children (5-17 years), and adults ( > 18 years).

Breakdown of subjects

  • Total 1737 OHCA due to drowning
    • 1669 adults
    • 32 older children
    • 36 younger children

Important findings:

  • Younger and older children were more likely to receive bystander CPR
  • Rates of return of spontaneous circulation (ROSC)
    • Younger children > older children > adults
    • Significant differences
  • Rates of survival to hospital admission
    • Younger children > older children > adults
    • Significant differences
  • Neurologically favorable outcome 
    • Younger children > older children > adults
    • Significant differences
  • Witnessed event significantly associated with improved one month survival and favorable neurological outcome
  • Overall survival with favorable neurologic outcome: < 1 %
  • Single area
  • Low numbers of children as compared to adults may hamper comparisons
  • Does not include differences in in-hospital treatment, but it is safe to say that most of the neurological insult is likely suffered during initial event
  • Does not include scene information like submersion duration.
The statistic we always worry about is neurological outcome.  In this study, younger children displayed much better outcomes.  This can be attributed to multiple factors including physiologic differences, lack of comorbidities, and the fact that in general children receive more bystander CPR.  In performing studies of this nature, we can uncover differences in the acute treatment of drowning victims which improve outcome.  What I would like to see in future studies is more focus on scene information and acute EMS treatments since that initial time-period has the most effect on neurologic injury.


Monday, June 17, 2013

Effectiveness and safety on in-water resuscitation performed by lifeguards and laypersons

Effectiveness and safety on in-water resuscitation performed by lifeguards and laypersons: A crossover manikin study
Authors: Winkler B, et al.
Journal: Prehospital Emergency Care, July/September 2013

By focusing on hypoxia as our primary cause of systemic injury in the drowning patient, it goes without saying that we should try and reverse it as fast as possible.  It makes sense that providing oxygenation to the patient as soon as possible, even if still in the water, would improve overall outcome.  This positive effect was shown in the only major study on the subject by Dr Szpilman in 2004.  Despite these findings, primarily due to the fact that in-water resuscitation (IWR) is a difficult intervention to perform, there is still question about whether this should be standard treatment.  Current ERC and AHA guidelines call for its use, but specify that it should be done only if it doesn't greatly delay overall treatment/transport and if the rescuer is comfortable performing the task.

Dr Winkler, who previously authored a study on the use of various airway adjuncts in the water, reports his findings on a study using the same study set up, which is designed to measure total rescue time, number of airway submersions, and amount of water aspirated by a simulated manikin victim during the rescue.  This study was primarily focused on evaluating the effectiveness and difficulty of performing IWR, compared with non-ventilation (NV) rescues, using both trained lifeguards and lay-persons.

Important findings:

  • IWR significantly increased rescue time, number of submersions, and volume of aspirated water
    • Lifeguards had significantly better rescue times with IWR and NV
    • No difference in two groups in terms of aspiration with IWR
  • Lifeguards performed significantly better IWR (Tidal volume and minute ventilations)
    • Lifeguards had relatively constant tidal volumes, slightly above recommended volumes
    • Lay-persons had progressively decreasing volumes through out rescue
  • Both groups reported increased difficulty when performing IWR
In terms of how this affects my practice, I don't think the evidence is present to justify performing IWR on all victims or making it standard for all lifeguards to perform.  The current thought by leading experts is that IWR should be attempted if the estimated time to shore or boat is > 5 minutes, and I tend to agree.  I do however think that there is enough evidence for the improved outcome with early ventilation and for the feasibility of IWR to perform 2 breaths, signal to your land-based team, and then begin bringing the patient in.  The most important factor is the confidence and physical capabilities of the rescuer.  This study was performed in a controlled/simulated environment which cannot come close to matching the mental, physical, and environmental stress of a real-world rescue.  All in all, a well designed study to meets the intended goals, and another piece of evidence to keep in the back of our minds.


Friday, May 31, 2013

An Essay on the Epidemiology of Drowning

The discussion of drowning epidemiology is often confusing and misleading. I will attempt to break it down in a meaningful way.

Drowning is defined as "the PROCESS of experiencing repiratory impairment as a result of submersion/immersion in a liquid medium". Drowning can only have 3 outcomes, 1-mortality (death), 2-Survival with morbidity (brain damage), 3- Survival without morbidity (no brain damage). There is no such thing as "near-drowning".

Drowning is often quoted as "the 3rd leading cause of unintentional injury death worldwide". This comes from the World Health Organization (WHO) Global Burden of Disease 2004 update. First, the WHO only logged 388,000 drowing deaths worldwide in 2004. More than 95% of these deaths occur in low and middle income countries (LMIC), where under-reporting is the rule more than the exception. When a person drowns in a remote area, anectdotal evidence suggests that they are simply buried, but never make it to the hospital where the data collection occurs. Compare that to the leading cause of accidental injury death worldwide-motor vehicle collisions (MVC's, AKA Road Traffic Acidents). Nearly every person that is in a serious car collision either gets taken to the hospital (since there are probably other cars around) or at least alert law enforcement or other authorities who can document the incident.

The most conservative estimate is that for every 1 drowning death that occurs, an additional 4 drowning deaths go unrecorded. 388,000 x 4 = 1.55 million. Add that to our original 388,000 and you get 1.94 million drowning deaths per year. But what about all of those non-fatal drowning incidents, some of which result in serious brain damage? For every drowning death, there are an additional 4 to 10 nonfatal drowning incidents. So if we take the most conservative estimate 1.94 million x 4 = 7.76 million drowning incidents per year!!!! This doesn't include floods, tsunamis, natural disasters, or boating accidents, but I won't go there now.

So, lets just go back to that small 388,000 number and break it down a little bit. The WHO says that it is the 3rd leading cause of unintentional injury death. Worldwide, about 2,270 children die every day from ALL causes of unintentional injury. The number 1 cause is car crashes (22.3%) and number 3 is drowning (16.8%). So that begs the question, what is number 2 (31.1%)? Other. Thats right, "Other", which includes categories such as smothering, asphyxia, choking, animal and venomous bites, hypothermia, hyperthermia, and natural disasters. I'd be willing to bet that there a few natural disaster drowning deaths in that category from tsunamis, floods, hurricanes, etc... Hurrican Sandy killed 117 people, nearly a third from drowning. So if the #2 cause of unintentional injury death is "Other", I move it down to #3 and always teach that Drowning is number 2 behind MVC's.

But what about here in the US? Based on the 2010 CDC data, Drowning is the #1 cause of unintentional injury death for children 1-4 (436), followed by MVC's (343). In 5-9 year olds, it is the #2 cause (134) behind MVC's (354). Finaly, in 10-14 year olds, drowning is again #2 (117) behind MVC's (452).

So, I would offer that Drowning, even if we take the really low under-represented numbers, is the #2 cause of unintentional injury death worldwide and in kids uner 14 in the US. It is the #1 cause of unintentional injury death in the US in kids 1-4. So lets give drowing the attention, care, and research that it deserves.

Written by Justin Sempsrott, MD

Friday, February 22, 2013

Efficacy of ventilation and ventilation adjuncts during in-water-resuscitation

Efficacy of ventilation and ventilation adjuncts during in-water-resuscitation
Winkler BE, et al
Resuscitation, 2013

This was a randomized trial performed to evaluate the effectiveness of in-water resuscitation using different airway adjuncts.  This study has many weaknesses, but overall it is always exciting to see randomized trials being conducted within the open water lifesaving community.  Here is a synopsis of the study and its findings:

  • Study design
    • 19 lifeguards participated
    • Each performed 4 rescues in randomized order
      • No ventilations
      • Ventilation with mouth-to-mouth
      • Ventilation with bag valve mask
      • Ventilation with laryngeal tube (supraglottic device)
    • Each rescue was 100 meters
      • Manikin with measurement capabilities used
      • Ventilation performed every 10 seconds
  •  Measurements
    •  Rescue Time: from time of obtaining manikin to crossing finish line
    • Number of manikin submersions
    • Tidal volume and minute volume
    • Aspirated lung fluid in manikin
    • Subjective difficulty per rescuer
  • Results
    • Rescue times longer when ventilations performed
    • More submersions occurred when ventilations performed
    • Increased aspiration with mouth-to-mouth and bag-valve mask
    • Highest tidal volumes with laryngeal mask
      • Lowest with bag-valve
      • Laryngeal mask had stable tidal volumes
      • Adequate minute ventilations with mouth-to-mouth and bag-valve
 As stated before, what I like about this study was it was a fairly nicely designed and standardized look at in water resuscitation.  One weakness of the study is that it only deals with the time between contact with the victim and reaching land.  What it doesn't account for is the difficulty of reaching the patient with airway adjuncts (i.e. getting a bag valve mask out to the patient).  Another weakness was the use of manikins, which can't properly simulate a human's airway or evolving lung compliance due to aspiration, but this is likely the only study design possible.  The idea of using a supraglottic device is enticing since it gives adequate minute ventilations and would theoretically provide a barrier against aspiration, but I do question the feasibility of carrying a device and a bag valve mask to deliver ventilations during a rescue.

Winkler BE, et al. Efficacy of ventilation and ventilation adjuncts during in-water-resuscitation–a randomized cross-over trial. Resuscitation; 2013.

Wednesday, February 6, 2013

Drowning related out-of-hospital cardiac arrests: characteristics and outcomes.

Drowning related out-of-hospital cardiac arrests: Characteristics and outcomes
Authors: Dyson K, Morgans A, Bray J, Matthews B, Smith K
Journal: Resuscitation, January 2013

This article is a retrospective review of data from the Victorian Cardiac Arrest Registry (VACAR), which aimed to answer the following questions:

  • Of those in cardiac arrest following drowning, what is the survival to hospital rate?
  • Of those in cardiac arrest following drowning, what is the survival to discharge rate?
  • What are some factors which determine these rates?
A total of 336 cases were analyzed, 77% of each involved patients < 18 years of age. The following are important findings:
  • 70.5% occurred in the ocean
  • 17.9% were witnessed
    • These individuals were more likely to receive bystander CPR
    • No significant difference in outcome directly related to bystander CPR
  • EMS resuscitation attempted in 48%
    • Only 8% of these survived to discharge
    • Poor survival for those who did not achieve return of spontaneous circulation with EMS
    • No survivors when EMS response time > 12 min
    • Upon arrival of EMS, majority of patients in PEA arrest of asystole
      • PEA: 20% survival to discharge
      • V fib: 30% survival to discharge
      • Asystole: 3% survival to discharge
This study has the following limitations
  • Performed in single region
  • Retrospective (although introduction stated "prospective")
  • Did not include data on lifeguard involvement, especially in cases of delayed EMS arrival
All in all I was very excited to see this study come out.  It is the type of study I would love to see done more in the US, as It gives Emergency Medicine professionals some objective data to base clinical prognosis on.  Unfortunately is does show an overall dismal outcome for those experiencing cardiac arrest due to drowning.  Further study should aim to include major interventions which may affect outcome and neurological outcome at discharge.


Friday, January 18, 2013

ST-segment elevation myocardial infarction after drowning

ST-segment elevation myocardial infarction after drowning

Authors: Hesham Rashad Omar, Madhu Shree Gundavaram, Ehab El-Khabiry, Yaseen Ali, and Enrico Mario Camporesi
Journal: Internal and Emergency Medicine (Italian Society of Internal Medicine)

Very interesting case study.  The morbidity and mortality from drowning stems from the primary hypoxic injury and can been seen in the end organ damage of patients, the most worrisome and devastating of which is usually encephalopathy.  This case highlights the cardiovascular effects of hypoxia in a patient who we would otherwise not expect to see it in.  The paper tells of a 16 year old patient who was brought in after a drowning injury in which the initial ECG showed ST segment elevations consistent with inferior MI.  The patient was then taken to the cath lab, but cath was cancelled due to resolving elevations in a repeat ECG;  eventual troponins were positive.  Unfortunately the patient continued to decompensate from there on out until he was diagnosed as brain dead.  

As we all know, MI can be the inciting event for drowning injury, but in a patient this age we can assume that it was an indicator of end organ injury.  I would have like to have seen a post-mortem report to determine if there was any cardiac abnormalities, but all in all an interesting case.


Monday, January 7, 2013

Lifeguard Fatigue and CPR

Effect of physical fatigue on the quality cardiopulmonary resuscitation: a water rescue study of lifeguards
Authors: Roberto Barcala-Furelos, et al.

This study, out of Spain, provided some evidence to support the idea that fatigue from an in-water rescue leads to sub-optimal CPR.  A study of this nature has been done before, but this one was performed after the updated 2010 CPR protocols.  As you can imagine, it doesn't provide any mind-blowing information, and pretty much serves to tell us what we already know, but this type of evidence may come in handy when designing training programs or lobbying for increased resources.

The basic design of the study:

  • Had lifeguards perform CPR on mannequins both during a resting phase and after enacting a simulated/standardized rescue
  • Used feedback mannequins to monitor quality of CPR
  • Compared CPR quality between genders and between resting and post-rescue 
Important results:
  • Gender did not effect quality of CPR
  • Overall, CPR quality was poor compared to standard
    • Low number of correct ventilations (very important in drowning)
    • Although in increase in compressions after rescue, there were less correct compressions performed
    • Fatigue worsened overall CPR
With high quality CPR, especially ventilations, playing such an important role in survival after drowning, this study should be taken into consideration when designing lifeguard training programs and drafting standard operating procedures.  Steps should be taken to maximize "real-world" scenarios with an emphasis on maintaing high quality skills despite the adrenaline rush and to account for this rescuer fatigue when establishing on-scene protocols and the roles of auxillary responders.