A scuba diving trip in the Maldives turned tragic this week when five Italian tourists failed to return from a deep-sea caving dive.
Authorities are investigating the circumstances surrounding the 160-foot dive, with various speculations suggesting that strong ocean currents, bad weather, fear, or oxygen toxicity might have contributed to the sad incident.
“Something might have gone wrong with the tank,” noted pulmonologist Claudio Micheletto in comments to Italian news. All five divers tragically lost their lives on Thursday.
“Oxygen poisoning or hyperoxia can lead to one of the most horrifying deaths in diving, and it’s a frightening possibility,” Micheletto emphasized, as he leads the respiratory department at the University Hospital of Verona.
The victims included Monica Montefalcone, a marine biology professor at the University of Genoa, and her 20-year-old daughter, Giorgia Somacar.
Additionally, the group included Muriel Odenino from Turin, Gianluca Benedetti from Padua, and Federico Gualtieri from Borgomanero.
As experts work to understand what occurred, here’s what to know about oxygen toxicity.
What is oxygen toxicity?
In simple terms, too much oxygen can be harmful.
Humans typically breathe in about 21% oxygen, but it can become toxic if inhaled in high concentrations or under high pressure for extended periods. This excess oxygen generates unstable molecules known as “free radicals.” These can overwhelm the body’s natural defenses, leading to cell and tissue damage.
Doctors categorize oxygen toxicity into two types.
- Lung oxygen toxicity: Usually a result of prolonged exposure to high oxygen levels, this mainly affects the lungs and airways.
- CNS oxygen toxicity: Occurs with short-term high-pressure exposure, mainly in deep diving, affecting the brain and spinal cord, which can lead to rapid and fatal changes.
How can oxygen poisoning happen? What are the risk factors?
Scuba diving is a common cause of this condition.
Divers generally breathe compressed air from tanks that have a mix similar to surface air — 21% oxygen and 78% nitrogen. But the deeper one dives, the more the pressure alters the situation.
As depth increases, oxygen’s effects intensify. Some experienced divers use gas mixtures with higher oxygen content to extend their dives, but these can become toxic more quickly under certain conditions.
Oxygen poisoning can also occur in medical environments. For example, patients undergoing hyperbaric oxygen therapy for conditions like decompression sickness are exposed to nearly pure oxygen under pressure, which can be lifesaving yet risky if exposure is prolonged.
Additionally, patients on ventilators in ICUs or premature infants receiving high oxygen levels for long durations may be at risk, although lung damage differs from the quick neurological impacts of deep diving.
What symptoms should you be aware of?
Symptoms can differ depending on the type of oxygen toxicity.
Pulmonary oxygen toxicity generally damages the lungs and airways, leading to issues like chest pain, coughing, and trouble breathing. Severe cases can cause parts of the lung to collapse.
On the other hand, CNS oxygen toxicity can strike quickly and is particularly alarming underwater.
Signs include tunnel vision, ringing ears, confusion, dizziness, nausea, numbness, muscle spasms, and sudden seizures. “During a dive, people can feel dizzy, pained, disoriented, and unable to resurface,” Micheletto explained.
Is there a way to treat it?
Yes, but timely intervention is crucial.
If divers exhibit symptoms of CNS oxygen toxicity, the first step is a slow and controlled ascent to lessen oxygen pressure. For those using oxygen-rich gas mixtures, switching to lower-oxygen options can also be beneficial.
Typically, returning to normal air at lower pressures improves most symptoms. However, if seizures happen while underwater, drowning can happen in a split second. In scenarios of pulmonary oxygen toxicity, treatment usually involves reducing or stopping high oxygen exposure.
While permanent damage is uncommon, lung recovery may take several weeks, and a chest drain might be necessary for collapsed lungs.
