Incident Insight - If You Can't Equalise, Abort

Sinus barotrauma can be very unpleasant

- Matías Nochetto

THE DIVER

The diver was a 26-year-old woman with approximately 200 lifetime dives.

THE DIVE

She did a single, morning dive to a maximum depth of 27 metres. She reported no troubles equalising or other complications during her descent. Approaching her safety stop near the end of the ascent, however, she was struck by a sudden massive headache, nausea and vomiting. She skipped the safety stop and ascended directly to the surface. The headache and vomiting continued on the boat, and she also experienced an onset of what she called dizziness. The crew helped her remove her gear and administered oxygen. After a few minutes with no improvement, the crew recalled the rest of the divers and called emergency medical services (EMS) and the DAN Emergency Hotline.

ANALYSIS

Further discussion revealed that the dizziness the diver reported was likely true vertigo. Vertigo is characterised by a spinning sensation and is usually accompanied by nausea and vomiting, while dizziness is a sensation of loss of balance.

In a diving context, a sudden onset of vertigo during ascent or descent is suggestive of ear barotrauma, with inner-ear barotrauma (IEBT) being most concerning. Ear pain may or may not be present. Vertigo is also common in cases of inner-ear decompression sickness (IEDCS). Symptom onset for IEDCS is usually not so sudden and dramatic, and the dive profile did not seem to be aggressive enough to immediately suggest IEDCS. Nevertheless, such a diagnosis could not be completely ruled out.

Distinguishing between IEDCS and IEBT can pose a significant diagnostic challenge, but doing so is critical because the two conditions require very different therapeutic approaches, and misdiagnosis and mistreatment could be harmful.