Suspected Arterial Gas Embolism After Glossopharyngeal Insufflation In A Breath-Hold Diver
Authors: Mats H. Linér, Johan P. A. Andersson
DOI / Source: 10.3357/ASEM.2571.2010
Date: 01 January 2010
Reading level: Intermediate
Why This Matters for Freedivers
This is a strong warning that packing can, in rare cases, trigger symptoms consistent with arterial gas embolism even at the surface and even in a young, healthy diver. The takeaway is that “more air” is not free — aggressive overexpansion can potentially injure lung tissue and allow gas to reach the arterial circulation, which is a serious safety risk.
Synopsis
Glossopharyngeal insufflation (“lung packing”) is widely used in competitive freediving to push lung volume above normal total lung capacity. Divers do it to store more gas and to make equalisation easier, especially for deep disciplines. But the lungs become very stiff at these extreme volumes, and the pressure across the lung tissue (transpulmonary pressure) can rise dramatically. In simple terms: packing can turn the lungs into an overinflated, high-pressure system — and that can stress delicate structures.
This paper reports a case that the authors personally witnessed in their laboratory. An 18-year-old competitive breath-hold diver (healthy, nonsmoker, training regularly) took part in an experiment that did not involve packing. After the session, he asked to measure his packed lung volume on a spirometer (something the authors say competitive divers often request). He performed a maximal inhale, then packed, then exhaled fully into the spirometer. His packed exhaled volume was 8.66 L compared to a measured vital capacity of 6.79 L earlier that day — a large increase consistent with substantial overexpansion.
Within about 30–60 seconds, he became distressed and developed transient neurological symptoms: tingling (paresthesia) around the right shoulder and reduced touch sensation on the right side of the neck. Motor function remained normal. The symptoms improved over minutes and fully resolved, and he had no recurrence during one hour of observation. The authors interpret the timing and pattern as suggestive of arterial gas embolism (a small amount of gas entering arterial circulation and temporarily affecting nervous tissue), even though the event was short-lived.
The discussion explains why this is plausible. High pressures from overexpansion can potentially cause small lung injuries (pulmonary barotrauma). If gas enters the bloodstream and reaches arteries, it can travel to the brain or other organs. The authors highlight that even minor, transient symptoms should be taken seriously because a larger or differently located embolism could cause severe injury. They also point out other risks linked with packing: circulation changes from increased intrathoracic pressure (reduced venous return and cardiac output), marked drops in blood pressure that can lead to syncope, and potential lung stress that may be relevant to other diving-related lung problems.
Overall, this case doesn’t prove packing always causes embolism — but it clearly shows that packing can produce alarming, immediate neurological signs consistent with a serious mechanism. The authors do not recommend using packing for lung overexpansion and urge divers and diving physicians to be aware of the possible complications.
Abstract
Introduction: Many competitive breath-hold divers employ the technique of glossopharyngeal insufflation in order to increase their lung gas volume for a dive. After a maximal inspiration, using the oral and pharyngeal muscles repeatedly, air in the mouth is compressed and forced into the lungs. Such overexpansion of the lungs is associated with a high transpulmonary pressure, which could possibly cause pulmonary barotrauma.
Case Report: We report a case of transient neurological signs and symptoms occurring within 1 min after glossopharyngeal insufflation in a breath-hold diver. He complained of paresthesia of the right shoulder and a neurological exam revealed decreased sense of touch on the right side of the neck as compared to the left side. Motor function was normal. The course of events in this case is suggestive of arterial gas embolism.
Discussion: Although the diver recovered completely within a few minutes, the perspective of a more serious insult raises concerns in using the glossopharyngeal insufflation technique. In addition to a neurological insult, damage to other organs of the body has to be considered. Both acute and long-term negative health effects are conceivable.