Clinical Trial Details
— Status: Enrolling by invitation
Administrative data
| NCT number |
NCT05831228 |
| Other study ID # |
Pro00111000_1 |
| Secondary ID |
|
| Status |
Enrolling by invitation |
| Phase |
N/A
|
| First received |
|
| Last updated |
|
| Start date |
September 1, 2023 |
| Est. completion date |
March 30, 2024 |
Study information
| Verified date |
July 2023 |
| Source |
Duke University |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Interventional
|
Clinical Trial Summary
The purpose of this study is to understand how ketogenic food products affect oxygen toxicity
in undersea divers. Oxygen toxicity affecting the central nervous system, mainly the brain,
is a result of breathing higher than normal oxygen levels at elevated pressures as can be
seen in SCUBA diving or inside a hyperbaric (pressure) chamber. This is a condition that may
cause a wide variety of symptoms such as: vision disturbances, ear-ringing, nausea,
twitching, irritability, dizziness, and potentially loss of consciousness or seizure. Because
nutritional ketosis has been used to reduce or eliminate seizures in humans, it may be
beneficial to reduce oxygen toxicity as well. The investigators hope this study will provide
a help to develop practical and useful methods for improving the safety of undersea Navy
divers, warfighters and submariners.
Description:
Central nervous system (CNS) oxygen toxicity continues to be a risk for military divers and
constrains their operations. Manifestations of this condition range from nausea, twitching,
and tinnitus to seizures and unresponsiveness, and the latter may lead to death by drowning.
The NAVY has a need for better methods to prevent or delay the onset of CNS oxygen toxicity
(CNSOT) and to safely expand the scope of diving operations. It is the broad objective of
this study to generate information that will enhance warfighter safety and performance in
relevant NAVY operations by reducing the risk of CNS oxygen toxicity.
It is known that nutritional ketosis through a diet with a high fat-to-carbohydrate ratio
(ketogenic diet) can reduce the frequency and severity of epileptic seizures in humans, and a
recent animal study has shown that dietary ketosis also delays the onset of CNSOT. In recent
years, ketone ester food products ketone esters have been made commercially available which
may elevate circulating ketone levels. The investigators aim to investigate whether ketosis
from commercially available ketogenic food products prior to a dive will delay the onset of
CNSOT.
The first aim of this study will be to determine the effect of ketone food product ingestion
on serum ketone levels, and document any relevant side effects. Post-ingestion ketone levels
will be trended for 3 different ketone food product regimens in 15 total subjects. Data will
be used to select the optimal ketone food product strategy to investigate in the second aim.
This second aim will be to evaluate the primary hypothesis, that pre-dive ketone food
products will prolong latency to CNSOT. To assess this, 20 subjects will be studied in a
randomized, controlled, double-blind, crossover methodology. After consuming either the
ketone food product or placebo, each subject will complete an immersed, head out hyperbaric
oxygen exposure while exercising on an underwater cycle ergometer at 2.06 ATA (35 fsw) until
oxygen toxicity symptoms develop or the maximum time limit of 120 minutes is reached. The
experiment will be repeated on a different day by each subject after consuming the opposite
(ketone food products or placebo). Primary outcome will be time to manifestation of CNSOT.
Physiologic monitoring throughout the study will provide secondary endpoints such as
cognitive performance, sympathetic nervous system stimulation via electrodermal activity,
electroencephalography, cardiorespiratory measures and end-tidal CO2/O2/N2; all adding to our
understanding of CNSOT physiology which may guide future mitigation and monitoring
strategies.
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