A 40-YEAR-OLD MALE did four rebreather dives one day from a liveaboard near Socorro Island. Maximum depths of the dives ranged from 35 to 39m, while dive-times were from 62 to 76 minutes.
The incident occurred on the third day of his series of 10 dives. All dives were uneventful, and he was out of the water at 6pm.

THE INCIDENT
About 3.5 hours after his last dive, the diver experienced nausea, vomiting and difficulty breathing during dinner.
His fellow-divers reported that he was unable to recognise them, and could not recall his home address or date of birth.
Fortunately, two doctors were among the passengers, and they examined the diver and noted dilated pupils, slurred speech, motor weakness and involuntary muscle contractions.
The crew activated the vessel’s emergency action plan. They placed the diver on oxygen at around 10pm, contacted DAN for medical advice, and looked to initiate an evacuation to a suitable medical facility.

THE COMPLICATIONS
Located in the eastern Pacific, Socorro is one of four volcanic islands that make up the Revillagigedos Islands. It is 240 nautical miles and a 24-hour boat-ride from Cabo San Lucas in Mexico.
There is a Mexican military airstrip on Socorro, but the runway is unable to accommodate larger aircraft, including those that can maintain sea-level pressure during flight. Inbound flights require permission from the military and must clear customs and immigration on the mainland before departing. The airstrip is insufficiently lit to allow take-off or landing at night.
As evacuation plans were being made, the diver’s symptoms began to resolve as he breathed the supplemental oxygen.
DAN established direct contact with the small military facility on Socorro, which has a functional hyperbaric chamber and professional staff.
They quickly recognised the severity of the diver’s condition and that a favourable window of opportunity existed to recompress him, and agreed to receive the patient.
There was no doctor at the chamber, but the diver’s improving condition made treatment there a good option.
The diver arrived at the military facility within four hours of his noted decline. He was able to walk in, and the chamber operators administered a US Navy Treatment Table 6, with guidance from DAN doctors.
This led to complete resolution of symptoms, and the diver was released to the boat for monitoring and frequent detailed neurological evaluations by the doctors on the vessel.
A well-known diving doctor also happened to be aboard another dive-boat in the area, and freely rendered his assistance. After a detailed evaluation, he confirmed full resolution of the patient’s symptoms.
The diver made an uneventful return home, and didn’t experience any return of symptoms, aside from some mild, intermittent general soreness.

DISCUSSION
Evacuation of this diver presented many challenges to the medical personnel involved in his care, and there are excellent lessons to be learned at each phase of treatment.
First, quick recognition of serious dive-related problems is important. In many cases, denial can lead to a refusal to accept that something is wrong and needs attention.
Divers may employ hopeful rationalisations to discount early symptoms, because a declared emergency has the potential to end further diving – for both the injured diver and others.
Even when an injury is finally recognised, a desire exists for things to spontaneously improve without the need to notify the divemaster.
In this case, an astute dive-team recognised abnormal symptoms and behaviour that led to a diagnosis of cerebral decompression illness (DCI).
Next, care-givers should administer first aid promptly and conduct further investigation. This dive-team quickly provided oxygen, which resulted in dramatic improvement in the diver’s condition, and then identified medical professionals in the group and engaged them in his care.
They contacted DAN for help with treatment suggestions and evacuation options. In remote locations, it’s important to be familiar with local medical capabilities and evacuation options before emergencies happen.
In this case, a two-leg flight would have been necessary to get the diver to a fully capable hyperbaric facility (at the University of California, San Diego).
There are facilities in Cabo San Lucas, but getting there would still require a flight or long boat-ride. Because of the limited capabilities of the airstrip, an unpressurised aircraft would have had to take the patient to the mainland, where a second flight would deliver him to San Diego for recompression therapy.
Also, symptoms developed in the evening, so any flight to the island would have had to be delayed until it was light, introducing further delay.
DAN notified the Mexican navy of the diver’s serious condition, and they understood that a delay in treatment could lead to a poor outcome.
Despite the busy tempo of the remote diving unit, the commanding officer opened his recompression chamber to a civilian diver. The chamber crew were true professionals, who quickly administered the necessary treatment.
Doctors on the dive-boat re-evaluated him and decided that he could remain aboard and travel back to the mainland according to the ship’s original itinerary. Three days after his treatment, he made an uneventful flight back home.

CONCLUSION
Four fortunate events positively affected this diver’s episode of serious cerebral DCI. First, the well-trained fellow-passengers and crew quickly recognised the problem and monitored his health until he reached the medical facility. Second, they administered O2 quickly, resulting in considerable improvement.
Third, a diving medicine expert was diving in the vicinity and able to help. And fourth, the highly professional Mexican navy opened a restricted facility that enabled definitive treatment and prevented potentially permanent neurological injury to the diver.
He was lucky, but he was also a beneficiary of divers’ willingness to help other divers. Such willingness can overcome significant obstacles, even international borders, as in this case.
Please take time to thank the professionals who are committed to helping injured divers – especially those who keep hyperbaric facilities open 247. They are diving’s unsung heroes.

ASK DAN’S EXPERTS

Is it safe to dive with a perforated tympanic membrane?

A perforated eardrum can be caused by diving, or have other causes, but most traumatic perforations heal spontaneously. Following an interval after they have healed, usually about two months, you can return to diving if your doctor feels the healing is solid and there is no evidence of Eustachian-tube problems.
If the perforation doesn’t heal, an ear surgeon can repair the damage, and after healing the same rules apply.
It’s important to check for chronic nose and sinus problems if there is no healing. Chronic perforations that don’t heal are a contraindication to diving. Some advocate diving with ear-plugs, but any water leakage could cause a severe infection.