Dive accident insights: current causes chaos

Overview of a incident resulting in decompression illness as a result of an unexpected current, courtesy of DAN - the Divers Alert Network

September 12, 2022

Divers on safety line - stock image

DAN

A 35-year-old British woman living in Singapore with roughly 2000 dives over a 19-year period - a qualified PADI and SSI Instructor (in non-teaching status) with specialities including deep and drift dive.

The TripA week’s liveaboard in the Maldives

The Dives

Three dives a day for the five days before the incident.
Almost all dives were deep, between 20 and 30 metres, with many of the morning dives below 30 metres.
On all dives, the diver remained well within no-decompression limits and carried out a safety stop on every dive.
Strong currents were present on most of the dives, in some cases the group was swimming against the current for significant portions of the dives.

Dive Profiles

The third dive of the day was to 40 metres. During the dive, it was discovered that the current had been misread. The group tried to swim against it into a channel. The current was too strong to swim against and the guide called the dive.
During the ascent and extended safety stop of around eight minutes (some of the group were in deco), the group were pulled out away from the channel and towards the open ocean.
The group surfaced a long way from the boat and there was a squall approaching. Even with SMBs and whistles, the group could not attract the attention of the boat that was waiting inside the atoll, a significant distance away. The current was still pulling the divers out to sea and the group was unable to stay together.
After around 10 minutes, the diver, who was the closest to the atoll, decided to swim across the current to reach an island to try to raise the alarm.
After about 15 minutes of extremely strenuous swimming, she was spotted by a speed boat which radioed the liveaboard. The liveaboard sent the dhoni (a traditional Maldivian boat), which picked the divers up just as the squall hit.

Onset of Symptoms
That night, the diver felt slightly nauseated but put it down to stress and went to bed early.

During the night she felt extremely mild tingling in her feet but it was so slight that she thought she could be imagining it. As nausea persisted, she decided to sit out the dive the next morning.

Feeling better after resting all morning, she did some snorkelling and then made the final dive of the trip that afternoon. That night she was still very tired and went to bed early.

After 24 hours, during which the whole group rested and slept, she flew back to Singapore. On arrival, she slept for 23 hours before going to work.

For the next three days the fatigue worsened, despite sleeping for around 14 hours a night. Her thinking became progressively con- fused, her short term memory was increasingly severely affected, she found it hard to walk in a straight line and by the third day her head and neck were numb.

Diagnosis
She called DAN AP and the hyperbaric doctor in Singapore who advised her to go to the chamber for immediate treatment. After undertaking tests at the hospital it was confirmed the diver had decompression illness (DCI) with peripheral neurological symptoms.

Treatment
The diver underwent three recompression treatments: The first a Table 6, followed by a Table 5 the next day and a further Table 5 treatment two days later.

Recovery
After the first chamber treatment the diver’s neurological symptoms and fatigue had improved greatly. She was sent home but the symptoms returned, with vertigo and nausea. Over the course of the next week she completed two further treatments. After the third treatment, the diver’s mental functions stabilised. However, for the next six months, she was easily fatigued.
After periods requiring any level of mental focus, she would suffer attacks of vertigo and nausea which required her to lie down with no light or sound stimulation for at least 15 or 20 minutes before it would pass. These attacks would occur several times a day at first, gradually decreasing in frequency and severity. The hyperbaric doctor prescribed pharmaceutical-grade ginkgo biloba and coenzyme Q-10 to assist in neurological recovery. Two years on, there is evidence that the diver’s memory is still mildly affected. The diver was advised to test for a PFO but the test was inconclusive.

Costs
US$8,454. All costs were fully covered by DAN AP.

Lessons to Learn

Use a line and float to remain visible to the boat throughout a cur- rent-prone dive.
Any symptom within 24 hours after diving should be considered possibly dive-related and expert diving medical advice, like DAN AP’s, should be sought promptly.
Avoid denial of symptoms.
Prompt and correct oxygen first aid and often subsequent recompression is important to help recovery.