Checklists

In the past 20 years, dive injuries and fatalities declined even as participation in scuba diving increased. This decline can be attributed to better training, equipment, research and access to health care. With the increase in participation there exists a need for continued improvement in diver safety. DAN’s research is an important part of the effort to enhance divers’ understanding of the risks, promote better protocols and raise safety awareness in the dive community.

Background

We know the most common causes of dive fatalities are drowning, arterial gas embolism and cardiac incidents. The majority of these deaths are labeled drowning, but most experts believe that drowning is usually preceded by other debilitating injuries. In 2008 a DAN^® study investigated 947 diving deaths and suggested a common chain of events in these deaths: the triggering event, the disabling agent, the disabling injury and the cause of death.

In an earlier study, researchers used a similar approach to review all work-related deaths in Australia that occurred from 1982 to 1984, identifying precursor events and contributing factors. Both these studies concluded that prevention strategies aimed at reducing triggers and precursor events could reduce injuries and fatalities.

It is not easy to look back at accidents and establish their root causes, but this approach allowed the authors of both studies to conclude most accidents are caused by preventable mishaps — unplanned and unwanted events that increase the risk of injury. The mishaps identified in both studies could be categorized as human errors, equipment problems or environmental factors. The most common diving mishaps are out-of-air scenarios, rapid ascents, equipment problems and entrapment. Reducing mishaps, especially human errors and equipment problems, seems to be the key to decreasing injuries and fatalities.

Checklists

One way to reduce mishaps is to remember important safety procedures and follow them. Avoiding, omitting, neglecting or failing to understand the importance of such procedures leads to human errors. These errors can compound with increasing stress, difficult-to-operate or malfunctioning equipment and environmental challenges. A checklist is a handy tool for reducing errors, improving performance and meeting safety standards.

Outside of Diving

Checklists have proven effective in high-risk disciplines including aviation and surgery. In aviation, their use is well enforced. Pilots and crews of military and commercial aircraft all have checklists for various procedures they must adhere to; completion and submission is required.

The World Health Organization (WHO) has promoted surgical checklists during the past four years. They have been found to reduce deaths and complications by streamlining communication among surgical teams and hospital staff.

The benefits of using checklists have also been demonstrated in recreational settings. A program called “Bikes, Blades and Boards,” conducted at Hamilton Health Sciences in Hamilton, Ontario, judged children’s performance wearing helmets using a helmet checklist and addressed mishaps related to fit, adjustment and condition of helmets. Children who participated in the program and used the checklist scored better in helmet use than children who did not. The experimental group retained the helmet-using skills even a year after the intervention.

In Diving

Standard predive procedures include a review of equipment, the dive plan and responses to unplanned events. We hypothesize that the use of a predive checklist reinforces these steps and reduces mishaps related to human error and equipment problems. Such reinforcement may be especially important in recreational diving because of the significant intervals between dives (months or even years) for many recreational divers.

Checklists have a long history in diving. U.S. Navy divers employ a thorough predive checklist before dives, and compliance is strictly regulated. The Professional Association of Diving Instructors (PADI) uses the acronym “BWRAF” when teaching predive checks to recreational divers. The acronym stands for BCD, Weights, Releases, Air and Final OK. Many mnemonics are used, including the well-known “Begin With Review And Friend” and a colorful variety of others. The National Association of Underwater Instructors (NAUI) diving manual features various checklists including one that uses the acronym “SEA BAG.” The safety topics referenced by this acronym are Site survey, Emergency, Activity, Buoyancy, Air, and Gear and go. The intent of this “on-site” checklist is similar to that of a predive checklist, but it provides a general review of safety considerations rather than a step-by-step list of tasks to complete. The American Academy of Underwater Sciences (AAUS) also advises divers to conduct a predive check and provides a format in its manual.

Divers are trained to conduct predive safety checks and may acknowledge the benefits checklists offer, but compliance is questionable. The extent to which any of these checklists are actually used is unknown, and no formal evaluations of their efficacy have been conducted.

Evaluation of a Predive Checklist

There is no gold standard of predive checklists. With input from dive-medicine researchers, dive instructors, physicians trained in dive medicine and diver medical technicians (DMTs), DAN developed a predive checklist for evaluation. It was pretested on 16 divers in a field setting to ensure clarity of content, assess the effort involved in completion and determine the acceptability of the checklist to divers.

To evaluate the checklist’s effectiveness, DAN conducted an intervention trial in the summer of 2012. The intervention groups of divers used DAN’s predive checklist, while the control group did not. At the end of each dive day, researchers asked all divers to complete a questionnaire about diving mishaps. The data were collected and are currently being analyzed; the incidence of mishaps between the two groups will be compared.

Extreme depth-time profiles and running low on air are known to increase divers’ risk of injury. To address these variables, researchers included a dive plan in the intervention: Participants were asked to plan the depth of their dive and to estimate their breathing-gas needs at different stages of the dive. Additionally, the intervention tool included four safety tips and a postdive log for divers to record actual dive parameters.

If the checklist promotes closer adherence to safety guidelines as we hypothesize, the primary benefit will be a decrease in mishaps related to equipment and human error and a consequent reduction in the incidence of injuries. Additional benefits from a public health perspective may include a decrease in the financial burden of treatment costs, a reduction in lost productive time due to injury, disability or death, and safer, more enjoyable experiences for divers. The checklist and the results from the intervention trials will be made public once the analysis is complete.