Credits
Neal W. Pollock, PhD; Mary F. Riddle, BA; Jenna M. Wiley, BS; Stefanie D. Martina, BS; Mitchell N. Mackey, BS Divers Alert Network, 6 West Colony Place, Durham, NC 27705

Introduction

• Breath-hold diving, in-water activity with a mask but without the use of scuba or surface-supply breathing gas, has grown in popularity as an underwater activity with numerous sub-disciplines.
• While generally safe, the aquatic realm is unforgiving and serious injury or death can occur. Learning from breath-hold incidents is important to increase diver awareness and promote safety.

Methods

• Divers Alert Network (DAN) developed a dedicated database to collect breath-hold incidents from 2004 forward.
• Cases are identified through automated keyword internet searches and voluntary submission. Incidents are followed up through requests to participants or local authorities.
• DAN reviewed cases from 2006 through 2011.
• Data are reported as number (n) of cases and/or mean±SD with ranges.
• The percentage of known data is specified for variables with incomplete records.

Results

• A total of 417 cases were captured; 308 fatal and 109 non-fatal.
• 51±9 (40-63) fatal cases annually (Figure 1).
• Incidents were reported from 56 countries.
• 46% in America; 11% in Australia; and single digits elsewhere.
• Victims were 41±17 (5-93) years of age (92% known) (Figure 2).
• Most victims were male (86%).
• Dive activity was described as snorkeling (46%), spearfishing (25%), freediving (18%) and collecting (11%) (92% known).
• Incidents were reported in ocean (90%), swimming pools (3.6%), lakes/quarries (3.3%), rivers/springs (1.8%) and other (1.3%) (94% known).
• Witnesses were present in 61% of cases (64% known) but generally with incomplete details of the event.
• The majority of victims were diving with a partner or group (59% known) (Figure 3).
• Disabling injuries were most obvious with acute animal or boat trauma. The most common disabling agent was loss of consciousness, typically intuited in fatal cases from witness reports and/or circumstances due to the lack of physical evidence.
• Initial triggers were frequently impossible to confirm in fatal cases.
• Excessive hyperventilation was most frequently suspected.
• Health issues implicated for many older victims.

Conclusions

• Breath-hold incidents frequently present with incomplete history and poor physical evidence.
• Excessive hyperventilation is the most commonly identified risk.
• Additional information is required to identify triggers and disabling injuries. Fully detailed non-fatal case reporting will likely be critical to improve our understanding of contributing factors

New Initiatives

• Augmenting the ongoing case capture program, DAN has developed an online reporting system to collect case reports for which more complete information may be available.
• Subgroup focus on breath-hold, rebreather and open-circuit modes.
• Incident Report