INITIAL NOTIFICATION AND CASE QUALIFICATION

The data collection process begins with an initial notification either from individuals that were aware of the fatality or from publicly available information acquired from active internet searches and automated internet alerts.

Google Alerts are used to monitor online news media outlets for keywords involving breath-hold and scuba related deaths. Sorting through media alerts is tedious work. Regardless of how refined the criteria, the number of redundant or irrelevant reports far exceeds the number of unique accident cases. Other fatality notifications come from individual reports. For example, friends and acquaintances of the victims and DAN members that are aware of DAN’s data collection efforts. The DAN Medical Services Call Center (MSCC) is the most valuable single resource. When called, the DAN Medical Services Department assists with diving incident management, regardless of whether the victim is a DAN member.

All reports of recreational compressed gas diving fatalities, that occur in the United States or Canada, or involve United States or Canadian citizens; regardless of location, are followed-up by a DAN staff member. For this report, recreational compressed diving includes: conventional students, certified divers, and diving professionals (i.e. instructors and dive guides), involved in diving that does not qualify as commercial. Rebreather diving fatalities are also reported for recreational compressed gas diving fatalities. Any dive-related deaths that occur outside the United States or Canada and involve citizens of other countries are not followed up on due to logistical constraints.

Non-recreational diving (i.e. military, commercial, fishing, public safety) are not followed up on by DAN staff. Breath-hold fatalities, including freediving and snorkeling, are reported separately and can be found in Section four of this report. DAN attempts to collect as much breath-hold fatality data as possible, when relevant contact information is available, regardless of the geography of the accident or citizenship of the victim.

REPORTS FROM WITNESSES AND NEXT OF KIN

DAN uses the Fatality Reporting Form to collect data from witnesses and family members. The form may be downloaded from the DAN website: diversalertnetwork.org/files/DivingFatalityReportingForm.pdf.

When necessary, DAN may contact additional family members to assist in the data-collection process. The family decides whether to complete the Fatality Reporting Form and/or authorize the release of the victim’s autopsy report.

The incident reporting form on the DAN website (dan.org/safety-prevention/incident-reporting/) may be used to report diving fatalities.

INVESTIGATOR AND MEDICAL EXAMINER REPORTS

Local law enforcement agencies, medical examiners, the coroners office, and both the United States Coast Guard (USCG) and Canadian Coast Guard frequently investigate diving-related deaths in their respective territories. DAN does not conduct investigations of diving fatalities.

Not all victims are subject to autopsies, and sometimes it takes over a year to complete investigations/produce reports. DAN tries to obtain all relevant reports; however, administrative hurdles exist and, in many cases (often due to privacy regulations by investigating agencies) reports cannot be collected, which impedes our ability to conduct analyses.

DATA ENTRY AND ANALYSIS

The DAN Research division maintains the diving fatality data on a secure server. Once all pertinent information has been collected and compiled, the results are analyzed and published in the DAN Annual Diving Report.

NUMBER OF FATALITIES COLLECTED IN 2018

Worldwide, via a combination of internet research and incident reporting, DAN was informed about 189 pertinent deaths involving diving. The number of follow-up (a citizen of, or an incident occurring within the United States or Canada) and non-follow-up cases from 2008 to 2018 are shown in Figure 1-1.

Figure 1-1

Number of Dive Fatalities by Year.

These values indicate that the number of follow-up cases reported in 2018 was less than in previous years, while the non-follow-up cases remained at a similar level. A breakdown of collected cases by DAN diver classifications is shown in Table 1-1 and highlighted in Map 1-1.

Table 1-1

Total Number of Collected Fatalities Worldwide in 2018 (n=189).

Map 1-1

Total number of Collected Fatalities Worldwide in 2018.

GEOGRAPHIC AND SEASONAL DISTRIBUTION OF FATALITIES

The number of follow-up scuba fatalities in the United States, Canada, and other countries for 2018 is shown in Table 1-2. It illustrates a significant drop in the number of reported cases that occurred in the United States and other countries, while follow-up fatalities in Canada remained constant as compared to the 10-year average.

Table 1-2

Number of follow-up cases in the United States, Canada and other countries for 2018 (n=55).

The number of follow-up scuba fatalities in the United States, Canada and other countries for 2018 is highlighted in Map 1-2.

Map 1-2

Number of follow-up scuba fatalities in the United States, Canada and other countries for 2018.

In trying to understand why there are fewer cases for 2018 than in previous years, the data’s geographic origin was explored. Table 1-3 shows cases by state in the United States. Florida and California, the two states that consistently had the highest numbers of scuba deaths in the past, averaged fewer cases than the 10-year average. Hawaii reported the most cases in 2018, and Massachusetts stood out with three times as many fatalities than its average over the last 10 years.

Table 1-3

The Number of reported cases in the United States by the state, for 2018, compared to previous 10-year average. Disclaimer: the cases indicated in the 10-year average were rounded to reflect whole numbers as they pertain to individuals themselves.

In Canada, the number of cases in 2018 was similar to the ten-year average, showing no deviance to the pattern. These results are shown in Table 1-4.

Table 1-4

Number of follow-up cases in Canada by province for 2018. Disclaimer: the cases indicated in the 10-year average were rounded to reflect whole numbers as they pertain to individuals themselves.

The number of deaths of United States or Canadian citizens that occurred outside their home countries are shown in Table 1-5. Overall, the 2018 average was less than the 10-year average for all participating countries except for Mexico; where a higher number of fatalities were reported. The Grand Cayman Tourism Board confirmed the two scuba fatalities that were reported.

Table 1-5

The number of fatal diving accidents for United States & Canadian citizens occurring in countries outside of the United States and Canada. Disclaimer: the cases indicated in the 10-Year Average were rounded to reflect whole numbers as they pertain (more...)

The 2018 data was compared to the 10-year data in three counties within Florida and California that are known for their high fatality counts (Table 1-6). In all six counties the number of fatalities in 2018 was less than that reported for the previous ten years. Information from the San Diego Medical Examiner (sandiegocounty.gov/content/sdc/me.html) indicated two scuba fatalities while DAN’s reporting system initially captured only one. The number of fatalities reported directly to DAN’s Medical Services Call Center was significantly less, as compared to previous years (see Table 1-7 below).

Table 1-6

Number of U.S cases in counties with most scuba fatalities.

Table 1-7

Total number of divers’ death notifications received through the emergency line.

After a thorough review of the data, it was concluded that in 2018 there were fewer scuba deaths in the United States and Canada than in previous years.

DEMOGRAPHICS OF DECEDENTS

Figure 1-2 shows the distribution of fatalities worldwide, by age and sex. Eighty percent of decedents were male (male, n=44; female, n=11), the average age was 54 years, and the median age was 56 years. A total of 67% of the fatalities recorded were 50 years of age or older. The youngest fatality was 10 years old, and the oldest fatality was 73 years old.

Figure 1-2

Age and sex distribution of reported fatal scuba accidents worldwide in 2018.

The previously noted trend of increasing age of victims seem to have tapered somewhat after reaching the mean age of 54 in 2015 (see Figure 1-3). While increasing age does not increase fatality risk when diving directly, it may affect health and physical fitness; both of which can indirectly increase risk. It remains however, that for most people, recreational scuba diving can be safely achieved if practiced responsibly.

Figure 1-3

Mean age of Fatalities by year (2004–2018).

DAN aims to identify populations that may be at an increased risk of suffering fatal incidents while diving continuously, with the aim of improving safety standards more uniformly over time. While the average age of recreational divers is (in general) rising, there appears to be a plateau at around sixty to seventy years of age, which may correlate with the stabilization of the average age of fatalities.

Other relevant factors, including health history, lifestyle, anthropomorphic measures (i.e. body weight and height), diving certification, and experience level were less available. Most of DAN’s knowledge on the health of divers invovled in fatal accidents is obtained from autopsy reports. Less commonly, DAN receives follow-up reports containing fatality information.

CHARACTERISTICS OF FATAL DIVES

The characteristics of a dive are typically comprised of its qualities or features, and serve as key identifiers to the person, place, or type of dive. Dives can be characterized by distinctive marks, focal features, critical attributes, location/topography/region, style, etc. All dives outlined below are categorized by characteristics including platform and environment, spearfishing and harvesting, training, underwater/non-commercial work, and wreck.

In 2018 known fatalities were a direct result of the following diving activities: leisurely diving or sightseeing (n=40), spearfishing (n=4), hunting/game collecting (n=4), training (n=3); and instructing (n=2), and other (unreported) diving activities (n=2).

In 18 cases, dives were made from a vessel with 19 cases orginating from a beach. In 16 cases, the platform was not reported. Most fatal dives occurred in an ocean/sea environment (n=40, 75%), nine in lake or quarry, and two in rivers or springs. In two cases, a description of the environment was missing. At least three instances occurred during wreck diving and one in a cave.

CASES — SPEARFISHING OR HARVESTING

The below cases involved divers that were participating in spearfishing or harvesting; however, the causes of deaths for all four were not necessarily attributed to these activities. All diver fatalities/victims are referred to in the below cases as, Diver ‘A’.

Case 2018-009. An experienced male diver in his thirties was harvesting lobster in choppy waters with two buddies. They entered the water at around 10:30 am from the shoreline. All three divers maintained visual contact throughout the dive. It was noted that on two separate occasions, Diver ‘A’ surfaced and then descended again. Diver ‘A’ had a precedent of doing this to re-establish location. When the dive was complete, all three divers surfaced together. Diver ‘A’ then turned on his back, took his regulator out of his mouth, and began a surface swim back to shore. His dive buddies decided to swim underwater to avoid the chop. When the buddies reached shore, they realized Diver ‘A’ was not with them. They looked back and saw his fins partially sticking out of the water. They swam back and found him face down and at an angle with his regulator out of his mouth. According to the dive computers that Diver ‘A’ and both of his buddies were wearing, the log shows that Diver ‘A’ came near the shore but sank beneath the water shortly before the other two divers reached the shoreline. Diver ‘A’ was underwater for 12 minutes before his body was retrieved. The medical examiner ruled this death a drowning.

Case 2018-021. An experienced male diver in his seventies, was diving solo and using a rebreather to spearfish. A friend who was diving on the other side of the same boat realized that he had not seen Diver ‘A’ for 30 minutes and started to look for him. He saw Diver ‘A’ yellow fins at the rear of the boat near the drift line, approximately 20 feet of seawater (fsw) (6.1 meters of seatwater [msw]) below the surface. Diver ‘A’ looked to be loosely entangled in the drift line, but his mask and regulator were still in place. He was pulled back to the boat and rescue breaths were attempted. Diver ‘A’ died despite additional medical efforts. It was reported that Diver ‘A’ had too much weight, his equipment was poorly maintained, and the diluent tank was empty. The medical examiner reported many issues involving his cardiac health (hypertensive and atherosclerotic cardiovascular disease; a stent in the left anterior descending coronary artery; myocardial fibrosis; cardiomegaly; and arterionephrosclerosis), but determined that the cause of death was drowning due to running out of gas and resultant loss of consciousness.

Case 2018-022. An experienced diver in his late forties participated in a spearfishing dive with a buddy. The buddy had a leaky air tank and returned to the raft, where he waited for Diver ‘A’ to finish his dive. When Diver ‘A’ did not return, the buddy alerted the harbormaster of a missing diver. His body was recovered the following day. Diver ‘A’ was reported as healthy prior to the dive. Without a detailed autopsy report available, Diver ‘A’ was classified as “a drowning from unknown causes” case.

Case 2018-036. A male diver in his late thirties was solo diving for scallops on a dive charter. When he did not surface as scheduled, other divers went back down to search for him. Diver ‘A’ was found tangled in his buoy line and out of air. The U.S. Coast Guard determined contributing causal factors, including: inexperience diving at the site and diving for scallops; a high rate of air consumption; use of a medication known to cause drowsiness, dizziness, and visual disturbances, insufficient evaluation by the diver and vessel master of the diver’s experience level for the scallop dive, entanglement in the dive line, limited self-rescue options as the diver did not carry an emergency source of air or dive knife, and limitations to rescue (as assistance was not readily available to the diver).

CASES — TRAINING

Two divers in their fifties died while training other divers. In one case, an instructor became unconscious and drowned while teaching students at 6.1 msw (20 fsw). In another case, an assistant instructor experienced a heart attack at the surface after a check-out dive with a student.

Additionally, one rebreather training diver died at the start of a rebreather dive, outside of supervised instructional time.

Case 2018-010. A male diver in his thirties died in a rebreather diving incident. He had started training on a rebreather six months prior and had 100 hours on the unit. He was a student participating in a trimix class but was reportedly not being supervised by an instructor when the incident occurred. Diver ‘A’ was on the surface talking with the boat crew while another diver went down to check visibility. A divemaster noticed Diver ‘A’ descending rapidly without his mouthpiece in his mouth. Reports are unclear as to whether the diver who checked for the sites visibility was also the divemaster who noticed Diver ‘A’ descending. The divemaster swam after Diver ‘A’, caught up with him at a depth of 38 msw (124 fsw), and brought him back to the surface. The boat crew initiated cardiopulmonary resuscitation (CPR) and transported Diver ‘A’ to the hospital where he was pronounced dead. The oxygen cylinder of his rebreather was not turned on. Diver ‘A’ was obese (BMI 33.1), but the medical examiner did not find any other major health issues. The cause of death was ruled as drowning due to hypoxia and loss of consciousness.

Case 2018-019. A male student in his late fifties was diving with a dive instructor. They were practicing switching from primary to secondary regulator when the instructor noticed Diver ‘A’ was having problems (not indicated what type of problems), so, the instructor brought him to the surface. On arrival at surface Diver ‘A’ was not breathing and CPR was started, but the victim never recovered. He was pronounced dead at the scene. The autopsy was not available. The cause of death remains unknown.

Case 2018-035. A female diver, in her early fifties, was completing her deep-water certification when she did not surface. The news report said she did not respond to the instructor’s signal to surface. No other details were available regarding the dive. The autopsy revealed complications of drowning, obesity (BMI 34.2), and hypertensive cardiovascular disease with mild cardiac hypertrophy (430 gr); as well as slight left ventricular hypertrophy (1.5 cm). It is likely that a disabling cardiac event occurred preceding drowning, which was ruled to be the cause of death.

CASES — NON-COMMERCIAL UNDERWATER WORK

Case 2018-011. A male diver in his forties was assisting with the retrieval of a tractor that fell into a canal, which was a maximum of 20 feet (6.1 m) deep. He was tied to a rope with an onshore tender. When the tender noticed the diver was staying underwater longer than expected, he pulled on the rope and found that the diver was dead. An autopsy was conducted; however, neither autopsy nor investigation reports were available.

Case 2018-045. An experienced male diver in his mid-sixties was diving with a colleague from a kayak. Diver ‘A’ surfaced after being down to 80 fsw (24 msw) for 20 minutes while repairing a mooring buoy. Upon emerging, he said that he did not feel well. Witnesses reported foam coming out of his mouth. Diver ‘A’ removed his weight system and attempted to remove the rest of his gear, but collapsed suddenly. A friend towed him to shore and called for help. Despite the response of emergency personnel and CPR efforts, Diver ‘A’ died at the scene. The medical examiner reported obesity (BMI 32.1), cardiomegaly (600 g), left ventricular hypertrophy (2.1 cm), and hypertensive cardiovascular disease. The medical examiner determined the cause of death as asphyxia due to drowning. DAN reviewers established immersion pulmonary edema (IPE) as both the disabling condition and the cause of death.

CASES — WRECK DIVING

Case 2018-012. A male diver in his late thirties was solo diving a wreck located at about 90 fsw. When he was overdue returning to the dive boat, a rebreather diver went down to look for him and found Diver ‘A’ entangled in a line. He put a regulator from a bailout tank in the mouth of Diver ‘A’, untangled him, and ascended. The rescue diver said he was breathing on the way to the surface. Once at the surface, Diver ‘A’ began vomiting but was conscious and speaking. The rescue was hampered by challenges with getting the diver onboard the vessel due to his body mass (136 kilograms/300 pounds). He was brought aboard, taken ashore (five-minute boat ride), and transferred to a waiting ambulance. Diver ‘A’ was then taken to the hospital, where he died shortly after arrival. Reports indicated that he had suffered a medical event either on the way to the surface or on the way to the hospital, but medical documentation could not be obtained to confirm this.

Case 2018-023. Diver ‘A’ was an experienced diver in his late sixties. He reportedly ran out of air while diving a shipwreck at 130 fsw (40 msw). He shared air for a time with another diver. The report does not indicate how long both divers shared air, nor does it make clear why the divers did not ascend immediately. Eventually, the other diver ascended and told people on the surface about Diver ‘A’ being left behind. A different diver went down and found Diver ‘A’ dead at the bottom. The autopsy revealed a blunt force injury, hypertensive and atherosclerotic cardiovascular disease, and cardiomegaly. The medical examiner determined the cause of death as drowning due to running out of gas. The head injury remained unexplained.

Case 2018-029. A male diver in his late forties was diving a wreck at the bottom of a lake (26.5 meters/87 feet deep). Upon surfacing, the Diver ‘A’ struggled to remove his diving helmet and, after a short time, became limp. His friends hauled him back on the boat. They had difficulty removing the helmet as they were not familiar with it. Diver ‘A’ was unconscious. His friends began CPR and brought him ashore where he was taken to a hospital and pronounced dead. Upon examination of his Go-Pro video and his dive computer profiles, the investigator concluded that the victim was either very low on or out of it and that he surfaced too quickly from a depth of 18 mfw (58 ffw). His ascent rate, as recorded by the dive computer, was 31 m/min (102 ft/min.) Information about tank pressure was not available. An autopsy was done, but the report was not released. A rapid ascent is often associated with an arterial gas embolism (AGE). However, the trigger for the emergency ascent after a relatively short dive, remains unknown.

FATALITIES BY DIVE PHASE

For the purpose of analysis, we use the following dive-phase categories: on the surface before diving, during the dive (including descent and ascent), and on the surface after diving. Dive-phase information was either directly or indirectly available in 41 of the 53 cases (79%).

In 29 cases the problem was noticed underwater by the affected diver or by another diver. In 13 cases, DAN was able to establish the following as a likely trigger:

• Cardiac events (3)
• IPE (2)
• Out of air (2)
• Entanglement (2)
• Nitrogen narcosis (1)
• Rapid ascent resulting in AGE (3)

PRE-DIVE

When death occurs at the surface before descent (pre-dive), the question arises as to whether it was coincidental or had a causality related to the dive. Pre-dive death happened in two cases, that are explained in more detail (Case 2018-008 below and Case 2018- 010 on page 10.)

Case 2018-008. A female in her thirties stopped moving after she dived into the water. The divemaster with her noticed and immediately brought Diver ‘A’ back to the boat. She was rushed to the nearest hospital, but could not be resuscitated. This sudden death may have been caused by a variety of reasons, but most likely was of cardiac in nature, and the immersion was likely the provocative factor.

ASCENT

In the four cases listed below, witnesses became aware that the ascending diver had developed a problem while coming up from his or her dive. However, one could argue that the divers decided to ascend because of the issues experienced while at depth.

Case 2018-017. Diver ‘A’ was an uncertified young boy who was diving with his father. He was breathing from his father’s spare regulator. At 7.6 mfw (25 ffw), Diver ‘A’ suddenly dropped the regulator and swam quickly to the surface. At the surface, he experienced an undisclosed medical emergency and later died on his way to the hospital. Diver ‘A’ most likely panicked, rushed to the surface while holding his breath, developed a lung overexpansion injury (also known as lung barotrauma), and died due to the AGE.

Case 2018-024. An experienced male diver in his late sixties signaled that he was out of gas 15 minutes into a dive to 9 msw (30 fsw) breathing enriched air (nitrox). Reports are unclear to whether Diver ‘A’ and his buddy shared air or if he used a backup air source as they surfaced. Upon reaching the surface, his buddy reported that Diver ‘A’ seemed agitated and was mumbling incoherently. Diver ‘A’ lost consciousness while waiting for retrieval and sank before his buddy could get to him. The inspection of the diver’s equipment revealed no reason for the breathing difficulty. Diver ‘A’ had sufficient reserve (162 bars/2350 psi) in his air tank, thus, the breathing problem he experienced was due to acute health issues and not to a lack of gas in his tank. The autopsy report noted a BMI of 24.6, little atherosclerosis, and some myocardial fibrosis. The report mentions “heavy lungs, filled with foam” and fluid present in the lungs and airways. Toxicology tests identified two blood pressure medications and opiates. The cause of death ruled by the medical examiner was cardiac-related death, while the DAN reviewers qualified it as immersion pulmonary edema (IPE).

Case 2018-030. A male diver in his sixties was diving with a group to 20.3 msw (61 fsw) when he reportedly noticed his air tank was approximately half empty. Diver ‘A’ signaled to his dive guide that he was going to ascend. At the surface, the boat crew realized he was unresponsive and jumped in to retrieve him and bring him back to the boat. The crew started CPR and recalled the remaining divers in the water. Diver ‘A’ was taken to the hospital where he was pronounced dead. The medical examiner established cardiac arrest as the cause of death. Other findings include obesity (BMI 31), high blood pressure, left ventricular hypertrophy, and cardiomegaly.

Case 2018-039. A male diver in his late fifties surfaced from a dive and was reported to have foam coming from his mouth. CPR was performed for 45 minutes. Diver ‘A’ was taken to the hospital where he was pronounced dead. In this case, while the witnesses became aware of Diver ‘A’ having problems upon ascent, it is suspected that IPE started before his ascent.

POST-DIVE

Three divers surfaced, exited the water, and lost consciousness. In all three cases, sudden cardiac death is most likely the cause of death, but in Case 2018- 038, we do not have any details to substantiate that assumption.

Case 2018-037. A male diver in his early seventies got back on the boat after a dive and complained that his suit felt too tight. He was assisted out of his suit and was given oxygen, after which he said that he felt better. However, a few minutes later, a crew member noticed Diver ‘A’ slumped over and unresponsive. The divemaster attempted CPR, and the diver began to vomit. CPR was resumed during transportation to the hospital, where the diver was pronounced dead upon arrival. Sudden tightness in the chest may have many causes, but with rapid progression to death and without other accompanying symptoms, it was presumed a likely sudden cardiac death.

Case 2018-038. A male diver in his fifties collapsed on the boat after returning from a dive and could not be revived. No additional details could be obtained.

Case 2018-040. A female diver in her sixties, accompanied by her husband, was diving to 18.3 msw (55 fsw). After several minutes, she signaled that she was out of air. The husband and the divemaster offered their secondary regulators to Diver ‘A’, which she declined, insisting on ascending. The divemaster noted that Diver ‘A’ had 2000 psi left in her tank. He assisted her in a controlled emergency surface ascent. Reports do not indicate whether Diver ‘A’ continued breathing from her own regulator after being informed of her remaining air, nor does it specify if she accepted a secondary regulator for the emergency ascent. At the surface, she was conscious and answered questions, in short, one-word responses. After boarding the dive vessel, she became unconscious, apneic and pulseless. CPR was initiated without success. Diver ‘A’ was declared deceased at the hospital.

CARDIAC CONDITIONS

Medical examiners reported cardiomegaly (an enlarged heart) in eight cases; however, the reference values were not reported. The heart’s weight in healthy people is generally proportional to body size expressed as weight, height, or body surface area (BSA). Still, there is a great level of variability.

Age and illness additionally affect the size of the heart. Reference values are based on various sample measurements and vary depending on size, makeup, and ethnic origin. We compared the heart weights of eight cases with two sets of reference values to determine if cardiomegaly was present.^{2, 3}

Four cases met criteria outlined by Vanhaebost et al. (2014) and one case outlined by Wingren et al. (2015). Some medical examiners may adopt a simple rule that a heart weight greater than 500 grams indicates cardiomegaly and a left ventricular wall thickness of 1.5 cm or greater indicates left ventricular hypertrophy (LVH).¹

Other medical examiners may defer to the appearance of the heart, microscopic changes in heart muscle, and the presence of factors that might cause the heart to work harder, increasing its muscle mass.¹ The latter was assumed to be utilized by medical examiners in most cases in our dataset.

In Table 1-9, we show the presence of obesity, hypertension, LVH, and significant atherosclerotic coronary disease, all of which were ruled cardiomegaly. Additionally, extensive co-morbidities were present in all cases.

Table 1-9

Contributing medical conditions in eight cases with cardiomegaly.

Table 1-8

Heart weight and reference values in eight cases with cardiomegaly determined by a medical examiner.

While it is not known whether these parameters played a role in the medical examiner’s diagnosis of cardiomegaly, such specific data diagnosis helped DAN’s reviewers establish cardiac issues as the disabling condition.

The largest heart observed was in Case 2018-031 (see below), and is classified as cardiomegaly according to all three references.^{1, 2, 3}

Case 2018-031. A male diver in his fifties surfaced after a dive and yelled for help before losing consciousness. He was transported to the hospital where he was pronounced dead. He had a history of past methamphetamine abuse in addition to several chronic conditions, including: congestive heart failure, asthma, hyperlipidemia, and hypertension. The official cause of death was acute methamphetamine toxicity. His heart weighed 710 grams.

In satisfying the criteria outline by one of three references, three more cases classified cardiomegaly.

Case 2018-006. A male diver in his late fifties was diving alone with a companion on land as shore support. About an hour later, a group of freedivers saw his body lying motionless on the seafloor. He was about 30 yards from shore, in roughly ten fsw. and was still in all of his scuba gear. The freedivers called for help and retrieved his body. Resuscitation attempts failed, he was pronounced dead at the scene. The diver was morbidly obese (BMI 45), had a history of high blood pressure and a stent placed in his right coronary artery. He also had indications of cardiomegaly (630g) and myocardial infarction.

Case 2018-045. (see page 11)

Case 2018-002. A male diver in his late sixties came to the surface following a dive to 55 fsw. His buddy noticed some blood on the mask of Diver ‘A’ and warned him. Diver ‘A’ cleared his mask, and both divers proceeded to swim towards the boat. Diver ‘A’ indicated that he was having difficulty breathing and the buddy started towing him to the boat. Diver ‘A’ lost consciousness just as they reached the boat. The crew assisted in bringing him on board and administered CPR. Once back at shore, Diver ‘A’ was transported to the hospital where he was pronounced dead. Diver ‘A’ had a history of high blood pressure and a recent cold. His heart weighed 550 g. Toxicology reports showed that the diver tested positive for barbiturates and hydrocodone and that he had extensive coronary heart disease.

Arterial Gas Embolism (AGE) was established as the disabling injury in six cases. In Case 2018-001, the medical examiner reported death due to air embolus in the heart. Other information was not available.

Case 2018-003. A trained cave diver in his fifties died while diving in a familiar cave system. The incident happened at about 51 meters (170 ft) deep. Diver ‘A’ and his buddy had turned for the swim back when the buddy noticed that he was having trouble reeling in his line. He waited for Diver ‘A’ to resolve the problem when he noticed Diver ‘A’ suddenly ascend and resultantly stir up silt in the water. The buddy deployed his safety reel and went to assist. He found the victim at the ceiling with his regulator out of his mouth. The buddy purged the regulator and tried to replace it in the victim’s mouth, but the victim was unresponsive. The buddy unwedged Diver ‘A’ and sent him to the surface while he completed his decompression before surfacing and calling for help. Another diver recovered the body of Diver ‘A’. The medical examiner ruled the cause of death as drowning. DAN reviewers considered subcutaneous emphysema reported by the medical examiner, panic, and a rapid ascent from 53 meters to about 9 meters (175 to about 30 ft); as well as AGE as likely disabling injuries. The victim also had a head injury, which could have rendered him unconscious and caused drowning.

Case 2018-014. According to witnesses, a male diver in his forties surfaced in distress and ceased breathing before his buddy and witnesses could get him to shore. The buddy stated that Diver ‘A’ appeared to be struggling with buoyancy or was running low on air when he signaled to surface. They attempted to do a safety stop, but Diver ‘A’ ascended rapidly, and the buddy followed. Rescuers and EMS administered oxygen and CPR but were unable to resuscitate him. The autopsy report was not available.

Case 2018-017 is described on page 12 and Case 2018-029 on page 11.

Case 2018-047. A male diver in his sixties descended to about 70 fsw with a group. His buddy noticed him swimming away from the group and downwards. She tried to catch up with Diver ‘A’ but began feeling tired before reaching him. The buddy estimated that they were at 56 meters (185 fsw) when she noticed that Diver ‘A’ was no longer swimming, rather he was slowly sinking, vertically. The buddy recalls being assisted by other divers to the surface at this point. The instructor and other witnesses indicated later that Diver ‘A’ continued to descend and ran out of air. He had to pull his emergency cord, sending him up too rapidly. The report does not indicate whether or not this was in an effort to drop weight. Witnesses saw Diver ‘A’ “popping” out of the water. He likely suffered from nitrogen narcosis, and most likely died of AGE.

DISABLING INJURY — IMMERSION PULMONARY EDEMA (IPE)

IPE was the suspected disabling injury in six cases. Four cases involving males were described earlier in this chapter.

Case 2018-051. A woman in her seventies with unknown diving experience indicated she wanted to surface from 60 fsw. When Diver ‘A’ and her buddy reached the surface, she started foaming at the mouth and had to be pulled from the water. Despite resuscitative attempts, death was pronounced at a local hospital soon after. The autopsy did not reveal any preexisting disease.

DISABLING CONDITION — LOSS OF CONCIOUSNESS

Cases 2018-010 and 2018-021 (page 10) both occurred with rebreather diving.

Drug-related deaths were suspected in two cases. In both cases, the drug was methamphetamine (see Case 2018-031).

Case 2018-015. A male diver in his early fifties was diving with a buddy when he suffered medical distress and surfaced. His buddy did not see what happened to Diver ‘A’ but swam over to assist him and found him unconscious and unresponsive with his face underwater. The buddy attempted to rescue the Diver ‘A’, but he sank to about 16.6 meters (50 feet) of depth. Another diver found him and brought him ashore about an hour later. Based on the lack of natural disease signs and positive toxicology tests, the medical examiner ruled acute methamphetamine intoxication as cause of death. Diver ‘A’ probably lost consciousness due to cardiac issues, which methamphetamine use can cause.

Methamphetamines can have effects on multiple organ systems. For divers, it is especially important to be aware of the cardiovascular effects of methamphetamine. An increase in catecholamine activity in the peripheral nervous system may be a consequence of methamphetamine use. The peripheral nervous system is responsible for modulating heart rate and blood pressure. High levels of catecholamines can cause narrowing of bloods vessels, increased heart rate, high blood pressure, and possibly myocardial infarction. The formation of fibrous tissue and increased size of heart muscle cells are features of catecholamine toxicity.⁴

SUICIDE

Case 2018-027. An experienced male diver in his sixties went diving with two young relatives. They encountered strong currents and decided to abort their dive. They were swimming back to shore when the two buddies realized that Diver ‘A’ had disappeared. His body was recovered at the bottom with a dive flag wrapped around him. Diver ‘A’ had a history of depression and panic attacks. The medical examiner ruled the death as suicide by an overdose of sertraline. Some of our reviewers suspected that Diver ‘A’ may have used sertraline to treat a withdrawal of Xanax (used to treat panic or anxiety), which may have caused agitation, confusion, drowsiness, and panic; all of which are likely to occur when facing a strong outgoing tide.