Clinical Trial Details
— Status: Enrolling by invitation
Administrative data
| NCT number |
NCT05299736 |
| Other study ID # |
MASHIEN |
| Secondary ID |
NATO STO HFM RTG |
| Status |
Enrolling by invitation |
| Phase |
|
| First received |
|
| Last updated |
|
| Start date |
February 18, 2022 |
| Est. completion date |
May 2024 |
Study information
| Verified date |
March 2022 |
| Source |
Göteborg University |
| Contact |
n/a |
| Is FDA regulated |
No |
| Health authority |
|
| Study type |
Observational
|
Clinical Trial Summary
Operating high-speed boats is dangerous. The purpose of this study is to establish what
levels and what characteristics of impact exposure cause injuries.
Impact-induced injuries are sometimes severe and cause permanent disabilities. The
slamming-impact exposure causes more injuries per workday than seen in most other peacetime
work. 12.
It is however NOT known which levels or kinds of impacts are dangerous and which are safe or
sustainable. To prevent injuries and to reduce fatigue onboard high-speed boats, this
knowledge is crucial.
Current standards and regulations lack relevance. They are based on mean values of
vibrations, and the stated exposure limit values are impossible to comply with even in normal
maritime operations.
The purpose of this study is to establish what levels and what characteristics of impact
exposure cause injuries.
This prospective observation study will measure human impact exposure and correlate this to
the occurrence and development of pain, used to indicate the risk of injury.
Description:
INTRODUCTION The ultimate purpose of the study is to protect professionals operating
high-speed boats from severe impact-induced injuries.
This requires establishing what kinds of impacts are dangerous and defining relevant limits
for sustainable human impact exposure.
Human impact exposure onboard high-speed boats causes pain and injuries, some severe,
permanent, and debilitating, physical fatigue, and cognitive impairment.
Increasing speeds and increasing numbers of high-speed boats used in professional operations
seem to increase these problems both in numbers and severity worldwide.
A lack of knowledge about the actual exposure and understanding of the causes of injuries,
and the implementation of counterproductive regulations, test methods, specifications may
have contributed to the increasing number of injuries.
To determine what impact exposure is dangerous, it is necessary to conduct a prospective
longitudinal study on humans being subjected to the relevant actual real-life exposure at sea
and correlate this exposure in real-time to a physiologic parameter indicating the risk of
acute injury.
Based on the new knowledge, relevant exposure limits can be proposed to protect operators
from injury and allow full operational capability underway and at target or mission.
The new facts may also lay the basis for a new quantitative measurement unit representing the
impact-induced forces challenging the anatomical structures and based on the magnitude and
characteristics of the impacts.
2. BACKGROUND A recent retrospective web survey of self-reported injuries on retired US SOF
(Special Operations Forces) HS boat operators, the SWCC2020 survey, indicates a significant
increase in injuries compared to a similar survey done on active duty personnel 20 years
earlier, Ensign 2000.
The SWCC shows 1.1 injury per person per year served, 50% of injuries affecting the spine,
33% of respondents having been unconscious onboard due to whole-body impacts, 40% of
respondents have a VA Disability rating of 70 to 100%.
This is an extreme work environment, and relatively few individuals in each country are
exposed. Hence, there are still significant knowledge gaps that must be filled to solve the
problems:
What is the actual exposure? When does it get dangerous? Which impact characteristics do
affect the risk of injury? How should these characteristics be weighed against each other? As
the impact exposure is unpredictable and stochastic, it is impossible to simulate in an
artificial environment.
The human body is a highly intricate "apparatus" designed to protect itself from noxious
exposure in several ways: It is also extremely difficult to predict the physiological
response from an unlimited variety of impacts. The body has 360 joints, 206 bones, and 600
muscles reacting to sudden external forces.
Many physiological factors influence how impacts affect the human body: bodyweight, stature,
central gravity, posture, muscular strength, physical shape, training status of the reflex
response, etc.
Many physical factors influence how impacts affect the human body: various characteristics of
the impacts such as peak acceleration value, rise time, frequency content, impact duration,
impact period, number of impacts, the direction of impact/force vectors, etc.
The lack of relevant knowledge has led to non-relevant exposure regulations based on
non-relevant measurement standards. The EU directive 2002/44, designed to control
occupational exposure to continuous vibration, is based on the ISO vibration standard 2631.
These documents use VDV, Vibration Dose Value, to quantify exposure to continuous vibration.
VDV has been shown to lack correlation to exposure to severe discrete impacts. Sed(8) has
been suggested but is also designed to quantify continuous vibration and has the same
limitations.
The vibration exposure limits stipulated by the EU directive 2002/44 lacks relevance for
exposure to discrete impacts. These limits are also impossible to comply with while
conducting sea rescue, law-enforcement missions, or military training in normal sea
conditions.
Hence, they are disregarded in most nations, and operators lack relevant regulatory
protection.
This study is based on the following facts: F. and assumptions: A. F. Hull impacts at sea can
exceed 20 g peak value. A. Higher peak values cause higher risks of injuries. F. Rise times
(time from 0 to peak g) of impacts can be as short as 6 ms A. Shorter rise times can cause
higher and more dangerous impulses. F. Impacts containing lateral forces cause more injuries
than purely vertical A. Impact exposure must be measured so that three force vectors, x,y,
and z, can be analyzed.
F. Impacts measured on a seat differ significantly from impacts measured on humans.
A. Impact exposure measured on the human is more relevant than exposure measured on the seat.
F. Horizontal impacts forces on humans cannot be measured on a seat. A. Human impact exposure
must be measured on the human body. F. Low pass filtering of impact data hides the
information about peak values and rise times A. Exposure data must be collected as unfiltered
raw data. F. Converting exposure data into VDV or Sed(8) changes peak values and rise times.
A. Exposure data must be collected as raw, unfiltered data. F. Pain can exist without injury,
but acute injury normally causes pain. F. Pain can be scientifically monitored using the
Nordic Minister Council PainDrawing form.
A. Events and persistence of pain can be used to indicate incipient injury.
3. METHOD The purpose of the study is to correlate impact exposure on boat hulls and humans
to a physiological parameter possible to use as an indicator of developing an injury. The
only such parameter possible to monitor daily in a cohort of hundreds is pain.
As this non-intervention study aimed to establish the actual normal exposure, exposure data
will be collected only during normal regular activities, and no transits will be done for the
purpose of collecting data.
The research method is designed to record impact exposure on hulls and humans onboard boats
operating in real sea conditions. Accelerations will be recorded as unfiltered, raw data.
This will allow for analysis of all the characteristics of impacts, potentially relevant for
physiological effects and risks of injury. This shall make it possible to assess the
significance of not only peak acceleration values but also of rise-times (time from 0 g to
peak g), impact duration, energy content, slam period (time between slams), and force vector
(direction of impact), etc. This will also make the results transparent and possible to
scrutinize.
3.1 MULTI-AGENCY STUDY DESIGN The collaborative effort aims to gather sufficient volumes of
data to reach statistical power. This requires all agencies to use the same study protocols,
hardware, and software and eventually share the relevant results in a shared database.
Agencies in 16 nations have already expressed their interest in participating. All subject
data will be anonymous and boat data stripped of potentially sensitive operational
information before being submitted to the shared database.
Crucial synergies can also be achieved by sharing costs, data, and results. To achieve
statistically significant results, a sufficient number of boats, subjects, and wave-slam
events can be gathered.
3.2 MEASURING IMPACTS ON HUMANS AND HULLS Whole-body impact will be monitored on two people
on board each boat at all times. Each boat will have a data logger installed for the entire
study period. This will be connected to a 3-axis accelerometer attached to the hull, close to
its COG. Two crew, preferably the coxswain and navigator, will wear 3-axis accelerometers
mounted to kidney belts and connected to the data logger. Recorded data will indicate the
actual, real-life impact exposure and the forces acting on the hulls and humans. This data
will show the real exposure and the relation between hull impacts and human impacts for each
boat type.
3.3 DATA LOGGER AND SENSORS A bespoke data logger device has been developed for this study.
MAREC (Marine Acceleration Recorder) is optimized for ease of use and installation. Installed
onboard and connected to 12 or 24 V DC, it will automatically start recording as soon as the
boat makes a speed of more than 3 kts. MAREC has 10 analog channels, of which 9 are used for
the three 3-axis accelerometers with a ± 25 g range. The sampling rate will be 600Hz. It also
has a built-in GPS receiver logging satellite time, position, heading, and speed. The 16 Gb
internal USB memory can store the data for the entire period of the study. Afterward or even
during the study, the data can be uploaded to a PC for analysis.
3.4 PAIN INDICATES RISK OF INJURY Pain is used to indicate if exposure causes a risk of
injury. All personnel serving onboard the boats will log events and development of pain
during the entire trial period.
A bespoke smartphone app, PainDrawing, will prompt subjects daily to log any relevant pain.
This is built on two scientifically validated methods, VAS, Visual Analogue Scale, and the
Nordic Ministers Council's pain-drawing form. The app can be downloaded for free for both
Android and iPhone.
Pain is the only physiologic parameter that can be used as an indicator of risk of injury and
be monitored and quantified over time, frequently enough to monitor a large cohort. Its
function is to prevent injury. Pain can be present without injury, but rarely an acute injury
manifests without pain.
Pain is also a relevant symptom, or sometimes a condition, which compromises physical
performance, endurance, and even mental capacity. It should be evident that exposure causing
pain during demanding operations must be avoided or limited as much as possible.
3.5 DATA ANALYSIS AND MANAGEMENT Participating agencies and organizations will upload the
collected exposure data to their local computers. The binary files will be converted and
presented in a graphic format legible even by laypersons.
The data analysis software will then select the relevant non-sensitive part for sharing and,
on command, be uploaded to a common big-data database.
A data analysis engine DAE, built for the purpose, will analyze the correlation of the
various characteristics of the impacts to the physiological response, reported as experience
and persistence of pain.
4. RESULTS AND APPLICATIONS Based on the expected results of the study, it will be possible
to calibrate instruments with dashboard-mounted indicators, telling operators when hull
impacts exceed safe levels by green, yellow, or red signals, where red should indicate out of
boundaries.
The results should also indicate the significance of the various analyzed impact
characteristics.
Ultimately the results can lay a base for relevant recommendations for allowable versus
dangerous levels of exposure to whole-body impact.
Participating agencies will gather information about how their various boats perform,
producing slamming impacts in actual use. They will also be able to see how various levels of
operator skills affect exposure.
5. CONCLUSION Current standards and regulations cannot quantify or help control human impact
exposure at sea.
In many fields of medical science, it is only possible to get relevant answers by studying
the human itself. In this case, the new knowledge needed to solve the problem can only be
established by studying what happens in real life.
Scientists and medical professionals have a duty to implement State-of-the-Art knowledge to
find the facts needed to solve these severe occupational health problems. Hence, the
investigators have chosen an empirical approach, investigating what happens to humans in
real-life at sea.
