If You Can’t Equalise, Abort: A Diving Barotrauma Incident Reviewed

The Diving Barotrauma Incident

The diver, with 200 lifetime dives, completed a single morning dive to a maximum depth of 27m. She reported no troubles equalising or other complications during her descent. Approaching her safety stop near the end of the ascent, she was struck by a sudden headache, nausea and vomiting. She skipped the safety stop and ascended directly to the surface. On the boat, she also experienced an onset of what she called dizziness.

Analysis: Vertigo and Barotrauma Risks

Further discussion revealed that the dizziness was likely vertigo, which is characterised by a spinning sensation and is usually accompanied by nausea and vomiting.

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.

Although much rarer, another possible diagnosis was a very bad sinus barotrauma with gas leaking into the cranial cavity (pneumocephalus). The sudden onset of a massive headache associated with a significant drop in barometric pressure accompanied by nausea, vomiting and vertigo was suggestive of such a rare diagnosis. The diver did report some difficulties equalising and what seemed to have been some sinus pain during descent as well as a sensation of pressure later during ascent. The diver’s recent history of a cold increased the likelihood of a bad sinus barotrauma. Pneumocephalus is usually diagnosed using imaging, but small amounts of gas can be reabsorbed in a short time. Because of the relatively small window for a positive diagnostic image and the harmful — even fatal — nature of pneumocephalus, ruling it out should be a priority.

Evaluation and Treatment

The diver’s X-rays revealed subtle signs that could indicate pneumocephalus, which warranted admission to the hospital. These findings, however, could not be reproduced during a CT scan several hours later. These diagnostic discrepancies prompted some discussions, but based on the case history, symptom presentation and initial imaging, the diagnosis was still thought to be pneumocephalus following sinus barotrauma. The patient had been breathing pure oxygen since surfacing, including during transportation, evaluation and hospital admission, which could have sped up the reabsorption of the gas.

In the absence of concrete evidence of pneumocephalus, the treatment plan was for the patient to continue to breathe oxygen, begin a course of antibiotics, undergo repeat CT scans and be observed for no less than 48 hours. A six-month follow-up appointment revealed the diver had a very good outcome and had no complications during or after her hospital stay.

Diving With Congestion and Equalisation Problems

Problems with sinus inflammation and congestion may be amplified by the sinuses’ natural responses to cold temperature. Exposure to cold triggers a reflex to limit heat that manifests as increased mucus production and swelling of mucous membranes. This is known as ‘cold-induced rhinitis’. Sea water can also have an irritating effect on mucous membranes, further stimulating mucus production.

Normally this has no negative consequences other than copious amounts of clear mucous when we surface but be careful when diving: If you are recovering from a cold or have other predisposing factors such as active allergies, gas movement between sinuses may be significantly more difficult. If you experience mild difficulty equalising at the beginning of a dive, chances are the increased mucus production and swelling of mucous membrane may make equalising even more difficult near the end of the dive. Remember you can always abort a descent; aborting an ascent is a lot more problematic.

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