Description Module
The Description Module contains narrative descriptions of the clinical trial, including a brief summary and detailed description. These descriptions provide important information about the study's purpose, methodology, and key details in language accessible to both researchers and the general public.
Description Module path is as follows:
Study -> Protocol Section -> Description Module
Description Module
Ignite Creation Date:
2025-12-24 @ 6:37 PM
Ignite Modification Date:
2025-12-24 @ 6:37 PM
NCT ID:
NCT03210857
Brief Summary:
The aim of this study is to demonstrate the effect of the voluntary neck extension in the occurrence of an increase in the pulsatility index of the right internal carotid artery in the amateur diver, realizing an apnea of two minutes or more.
Detailed Description:
In literature concerning apnoea, accidents have been described during neck extension.
Accidental drowning are frequent on the French coast every year and many of them concern apneists victims of apnoeic blackout.
Neck extension is thus suspected to possibly produce an apnoeic blackout at the end of the dive since 1965, when Sir Sciarli (diving medicine pioneer) suspected this hypothesis.
Physiologically, during a dive in apnea, the human cardiovascular system is subjected to a parasympathetic dominance, via the apnea reflex and the diving reflex. This parasympathetic dominant could be reinforced during a neck extension at the end of snorkeling during the ascent.
Hypothesis: the neck extension at the end of apnea contributes to increase the pulsatility index of the right internal carotid artery by vagal component and thus causes a decrease in cerebral blood flow and may lead to the initiation of syncope in the healthy amateur free diver or underwater fisherman.
Study:
NCT03210857
Study Brief:
Protocol Section:
NCT03210857