Charles, John

Kundrot, Craig

Norcross, Jason

Steinberg, Susan

NASA Technical Reports Server

Decompression Sickness 
Case Study of Identification of Knowledge and 
Disposition Gaps Using Principles of Continuous 
Risk Management 
Jason Norcross  Wyle Science, Technology and Engineering Group 
Susan Steinberg, Ph.D. Wyle Science, Technology and Engineering Group 
Craig Kundrot, Ph.D. NASA Human Research Program 
John Charles, Ph.D.  NASA Human Research Program 
 
February 15, 2012 
https://ntrs.nasa.gov/search.jsp?R=20120007755 2019-08-30T20:00:42+00:00Z
Page No. 2 HRP Investigators Workshop 2012 
Human Research Program 
Evidence Risk 
Gap 
Task 
Deliverable 
Deliverable 
Task Deliverable 
Gap 
Task Deliverable 
Task 
Deliverable 
Deliverable 
Research continually informs the evidence base  
HRP Program Architecture 
Risk mitigated to 
acceptable level 
Page No. 3 HRP Investigators Workshop 2012 
Human Research Program 
Translating  R&D into  
Continuous Risk Management 
CRM  
Decision 
Flow 
CRM Activities R& D Activity Gap Target for 
closure 
Risk 
Definition 
Likelihood (L) 
Consequence (C)   
Mission Attributes 
Time frame 
Data mining 
Enabling Technology 
Phenomenon 
Mechanism 
 
Knowledge  ID mission 
attributes 
Quantify 
likelihood, 
uncertainty, 
consequence 
Policy ID quantitative 
closure criteria for 
disposition gaps 
Epidemiology, 
statistics, clinical care 
guidelines 
 
Disposition-
policy 
NASA approval 
of acceptable 
level  risk 
Disposition Watch 
Accept 
Mitigate 
Techwatch 
Standards 
ID &  develop 
countermeasures 
Mitigation Yearly update 
Flight rule 
↓ L or C 
Page No. 4 HRP Investigators Workshop 2012 
Human Research Program 
Focusing Mitigation Gaps 
R&D Activities Category of Gap Target for closure Deliverables 
Research on 
phenomenon or 
mechanism 
Conceptual model ID risk factors for 
countermeasure 
development 
Model 
Clinical Procedure Predict Quantitative 
modeling 
Model 
Clinical Procedure 
 
Prevent Countermeasure 
to ↓L ± CI 
Countermeasure 
Clinical Procedure Diagnose Measurement 
protocol 
Technology_Tool 
Clinical Procedure Treat ↓ C Countermeasure 
Clinical Procedure Detect/Monitor Flight technology Technology_tool 
Clinical Procedure 
 
Rehab ↓ C Countermeasure 
Clinical Procedure Surveillance Protocol Technol gy_tool 
Page No. 5 HRP Investigators Workshop 2012 
Human Research Program 
First Draft – Defining the Gaps 
 DCS had been a 
gap under the broad 
EVA risk 
 DCS had no defined 
gaps, but many 
tasks 
 Initial draft looked 
for similarity in the 
tasks  
• Did not consider 
closure criteria or 
interim metrics 
Nucleation Mechanisms 
Microgravity effects on VGE 
Intermittent Recompression 
Microgravity 
effects on DCS? 
DCS Treatment Model 
DCS Risk Definition 
Nitrogen Elimination 
Predictive Model for DCS 
DCS prevention and 
treatment 
Bubble 
mechanisms? 
 
Page No. 6 HRP Investigators Workshop 2012 
Human Research Program 
Gap Type 
DCS 1: What is the effect of 
microgravity on DCS? 
Knowledge Gap: Data, phenomenon, 
mechanism 
 
DCS 2: How does activity level during 
depressurization affect DCS? 
Knowledge Gap: Data, phenomenon, 
mechanism 
 
DCS3: What are the physiological 
characteristics that increase DCS risk? 
Knowledge Gap: Data, phenomenon, 
mechanism 
DCS 4: What affects N2 elimination? Knowledge Gap: Data, phenomenon, 
mechanism 
DCS 5: What are the mechanisms that 
cause bubble formation and growth? 
Knowledge Gap: Mechanism 
DCS6: How can DCS be prevented 
and/or treated in flight? 
Mitigation gap 
 
DCS Gaps – First Draft 
 
Initial 
• Too much overlap with several tasks 
straddling 2, 3 or more gaps 
• Knowledge gaps are the most 
difficult to define closure criteria 
• Gaps were not worded with clos re 
in mind 
• Mitigation gap held everything 
else: 
• Risk definition 
• Prediction models 
• Procedures/Flight Rules 
• Treatment  
 
Page No. 7 HRP Investigators Workshop 2012 
Human Research Program 
Gap Type Target for Closure 
DCS 1: We do not know the acceptable DCS risk 
with respect to the work efficiency index (WEI) for 
exploration. 
Risk definition & 
disposition-policy 
HSRB approval  
Approved NASA Standard / Requirement 
DCS 2:  We do not know the contribution of specific 
DCS risk factors to the development of DCS in the 
Space Flight Exploration Environment? 
Knowledge gap: 
Data, 
phenomenon, 
mechanism 
Obtain effect size as a function of individual 
variance for each risk factor of interest in 
order to include in the DCS prediction 
model 
DCS3: We do not know the conditions that cause 
bubble formation, growth and elimination in human 
tissue 
Knowledge gap: 
Mechanism 
 
List putative causes to investigate/set of 
outcomes to be explained 
DCS 4: We do not know to what extent can 
physiological and environmental factors be 
incorporated and validated in a model DCS for 
micro and reduced gravity? 
Mitigation gap- 
Prediction (Model) 
 
Validated model for expected Exploration 
environment, which meets requirements of 
NASA-STD-7009 
DCS 5: We do not know what validated procedures 
will adequately prevent DCS? 
 
Mitigation gap- 
Prevention 
PB procedures that meet the accept criteria 
for DCS prevention, which will be based on 
the definition of acceptable risk standard for 
the Exploration environment 
DCS6: We do not know what new developments 
related to DCS will come from other investigators? 
 
Mitigation gap - 
Watch 
Current year/IRP end date x100=% 
completion 
DCS Interim Gaps- Post HRP Review  
- Gap creation determined by target for closure 
On paper, these gaps 
sounded different, but 
when trying to identify 
how to keep track of 
interim metrics, we saw 
that they needed to be 
reorganized. 
Page No. 8 HRP Investigators Workshop 2012 
Human Research Program 
Gap 2 and 3 Task Reorganization 
Gap 2 - Risk Factors 
 Nucleation Mechanisms 
 Prevalence of VGE after 
Depressurization in Microgravity 
 Exploration EVA Environment 
Characterization 
 EVA Simulator Development 
 Data Mining for DCS 
Physiological Risk Factors 
 N2 Elimination 
 Abbreviated Purge 
 Exercise Saturation Equivalent 
Testing 
 
Gap 3 - Bubble Mechanisms 
 Intermittent Recompression 
 Animal Models to Evaluate DCS 
 
 
 Exercise Saturation Equivalent 
Testing 
 Nucleation Mechanisms 
 N2 Elimination 
 
Page No. 9 HRP Investigators Workshop 2012 
Human Research Program 
DCS Gaps – Final 
- Both target for closure and interim metrics considered 
Gap Type Target for Closure 
DCS 1: We do not know the acceptable DCS 
risk with respect to the work efficiency index 
(WEI) for exploration scenarios. 
Risk definition & 
disposition -policy 
HSRB approval  
Approved NASA Standard / Requirement 
DCS 2:  We do not know the contribution of 
specific DCS risk factors to the development of 
DCS in the Space Flight Exploration 
Environment. 
Knowledge gap: 
Data, 
phenomenon, 
mechanism 
Obtain effect size as a function of individual 
variance for each risk factor of interest in order 
to include in the DCS prediction model 
DCS3: We do not know the mission related 
factors that contribute to DCS risk 
Knowledge gap: 
Data, phenomenon 
 
EVA Simulator for PB validation trials 
DCS 4: We do not know to what extent can 
physiological and environmental factors be 
incorporated and validated in a model DCS for 
micro and reduced gravity? 
Mitigation gap- 
prediction (Model) 
 
Validated model for expected Exploration 
environment, which meets requirements of 
NASA-STD-7009 
DCS 5: We do not know what validated 
procedures will adequately prevent DCS? 
 
Mitigation gap- 
prevention 
PB procedures that meet the accept criteria for 
DCS prevention, which will be based on the 
definition of acceptable risk standard for the 
Exploration environment 
DCS6: We do not know what new 
developments related to DCS will come from 
other investigators? 
 
Mitigation gap - 
Watch 
Current year/IRP end date x100=% completion 
 
Page No. 10 HRP Investigators Workshop 2012 
Human Research Program 
Gap 2 and 3 Task Reorganization 
Final 
Start 
Gap Task 
Final 
Gap Rationale 
2 , 3 Nucleation Mechanisms 2 
Gap 2 focus is physiological and not 
DRM specific 
2 , 3 N2 Elimination 2 
2 Abbreviated Purge 2 
2 Prevalence of VGE after Depressurization in Microgravity 2 
3 Intermittent Recompression 2 
3 Animal Models of Recompression 2 
2 Data Mining for DCS Physiological Risk Factors - 
This is really a subset of work done in 
many of the tasks and did not need to be 
called out separately 
2 Exploration EVA Environment Characterization 3 
Gap 3 focus is on external factors 
(Environment and EVA factors) and is 
DRM specific 2 EVA Simulator Development 3 
2 , 3 Exercise Saturation Equivalent Testing 4 
Results of this work will actually feed into 
a separate model / tool to facilitate DCS 
research 
Page No. 11 HRP Investigators Workshop 2012 
Human Research Program 
 
Example Interim Metrics 
 
DCS 1 – Risk Definition (DRM Specific) 
Task DRM NEA Lunar Mars 
Define Exploration mission success drivers 0 0 0 
Define medical operational drivers and 
consequences 
0 0 0 
Analyze trades between levels of risk, prevention 
and treatment 
0 0 0 
Develop DCS Disposition Policy for Exploration 
Program 
0 0 0 
Define acceptable DCS risk for Exploration Program 0 0 0 
HSRB Approval of DCS Risk 0 0 0 
Approved DCS Risk Prevention Standard 
(Deliverable) 
0 0 0 
Approved DCS Treatment Standard (Deliverable) 0 0 0 
Closure metric €= (number of tasks completed/number of tasks) x 100 
Note: 0=incomplete, 1=complete 
Page No. 12 HRP Investigators Workshop 2012 
Human Research Program 
 
Example Interim Metrics 
 
DCS 2 – Risk Factor Contributions 
# Task Title Step # Step Title 
Step 
Weight 
Status: 
0=incomplete 
1=complete 
1 
Nucleation 
Mechanisms 
1 Experiment 1 10% 0 
2 Experiment 2 10% 0 
3 Experiment 3 10% 0 
4 Experiment 4 10% 0 
2 VGE in Microgravity 
1 
VGE monitoring capabilities in 
microgravity while depressurized 
10% 0 
2 # subjects complete/# subject needed 10% 0 
3 N2 Elimination 1 # subjects complete/# subject needed 10% 0 
4 
Intermittent 
Recompression 
1 # subjects complete/# subject needed 10% 0 
5 
Animal Model of 
Recompression 
1 # animals complete/# animals needed 10% 0 
8 Abbreviated Purge 1 # subjects complete/# subject needed 10% 0 
Closure metric €= Step Weight x Completion Status Gap Closure: 0% 
Page No. 13 HRP Investigators Workshop 2012 
Human Research Program 
 
Example Interim Metrics 
 
DCS 4 – Models 
Credibility Factor 
Exercise Saturation 
Equivalent Model 
DCS Prediction 
Model 
DCS Treatment 
Model 
Target 
Score 
Actual 
Score 
Target 
Score 
Actual 
Score 
Target 
Score 
Actual 
Score 
Verification 2 1 3 2 2 1 
Validation 2 0 3 2 2 1 
Input Pedigree 3 2 4 2 3 2 
Results Uncertainty 2 1 3 2 2 1 
Results 
Robustness 3 2 3 2 3 2 
Use History 3 0 4 2 2 1 
M&S Management 2 1 4 1 4 1 
People 
Qualifications 3 1 3 1 4 1 
This addresses model development, but what about model maintenance ? 
Page No. 14 HRP Investigators Workshop 2012 
Human Research Program 
 HRP is an applied research program aimed at mitigating risk. 
 The described method provides a unifying framework for identifying 
gaps and their metrics that can provide meaningful information to 
continuous risk management. 
• Identification - gaps address each area of CRM decision flow 
• Focus – for closeable gaps 
 Avoid combination of risk definition and disposition in same gap  
 Use of standard concept of clinical care to focus mitigation gaps 
 Consolidation of knowledge gaps on the mechanism of DCS helped 
us achieve well defined closure criteria and interim metrics 
 Current orientation of HRP - destination agnostic 
• Use of interim metric for each exploration DRM 
Conclusions 


Decompression Sickness: Case Study of Identification of Knowledge and Disposition Gaps Using Principles of Continuous Risk Management

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server