ICL11_Barotrauma - Ear/Sinus Block - Clinical Finding Form (CliFF)

Sep 23, 2026

Uploaded by Angel

Clinical Finding Form (CliFF) for ICL11 Barotrauma (Ear/Sinus Block) defines ear and sinus barotrauma as a mission-dependent medical condition driven by ambient pressure changes during EVA activities. The document explains risk timing, under-reporting limitations, and the per-crewmember incidence accounting method. It details how the MEDPRAT Evidence Library model imports incidence categories, EVA-related statuses, and distribution parameters, and summarizes spaceflight, analog, and terrestrial literature to support an overall Bayesian incidence proportion estimate.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages13

Reading Time33 min

AccessFree to download

Background

EVA and ambient pressure mechanism

Limitations and risk accounting

Under-reporting and transition events

Per-crewmember incidence implementation

Incidence data model

Imported fields and distribution sampling

Literature basis

Spaceflight incidence

Analog literature

Terrestrial literature

Overall incidence summary

Bayesian posterior and parameter values

Incidence details

Table: incidence model structure

Clinical Finding Form (CliFF) ICL11_Barotrauma (Ear/Sinus Block) This condition is most likely to be associated with ambient pressure changes during an EVA. Therefore. inflight data would be most applicable. Barotrauma of the ear and sinuses occurs when there are pressure changes in the gases trapped within these cavities. This condition happens when there is a difference in pressure between the enclosed volume and the ambient pressure , and the change in ambient pressure overcomes the capacity of the enclosed space to equalize. Changes in pressure occur during space flight missions when the crewmember is transferring between habitable volumes of differing pressures (such as in an airlock) , when pressurizing and depressurizing for an EVA, and when contingencies result in changing pressures in the spacecraft. During some space shuttle missions, the cabin pressure was lowered to 10.2 psi to reduce the amount of time needed to pre-breathe by EVA astronauts. It is felt that the risk of barotrauma at constant cabin pressure is extremely low and can be considered zero. Accordingly, the incidence is based on the number of EVA’s that are performed during a mission with each participating crewmember at risk. It is felt that this approach represents a significant improvement from the previous IMM CLIFF that covered this condition. This medical condition is mission phase dependent. It is postulated to occur only during the pressure changes associated with EVA. The risk is considered to be zero during periods when the cabin pressure remains constant. Limitations • Under-reporting for this condition could have occurred during past space missions since barotrauma may be mild and easily cleared by the crew. This could result in underestimation of the incidence. • If there are significant cabin pressure changes during transition from a lunar/Martian lander and habitat to an orbiting vehicle , these events may also result in barotrauma. Each such occurrence should be considered as a separate at-risk event , equal to an individual EVA. Reconsideration of these risks will need to be done after IMPACT 1.0. • It is important that MPRAT implement the calculated incidence on a per-crewmember basis. In other words, if three crewmembers experience a pressure change as a result of an EVA, these are three separate events. INCIDENCE DATAINCLUDED IN THE MODEL The model imports the following incidence information from the MEDPRAT Evidence Library Database: incidence data category, space adaption status, EVA status, incidence data type , incidence and occurrence distribution data and incidence data characteristics. Data category defines the type of data available for incidence calculations (i.e. raw data vs. adjusted data) . Space adaptation identifies medical events that where onset occurs in the first 5-7 days of flight and does not reoccur. EVA-related incidence values identify medical events that occur only during an EVA. Incidence values types vary by data category and define the number of medical events per person-year (rates) or medical events per person at-risk (proportion) for each medical condition. Incidence values can be modified by crew characteristics such as gender sex and certain crew medical history characteristics. Modifying characteristics are noted below and incidence values are listed individually for each characteristic. Distributions are assigned to medical events incidence values and occurrences in the model. For each crewmember in a given trial, the incidence and number of occurrences of each medical condition are randomly selected from these probability distributions. Detailed descriptions of the distributions are included in the MEDPRAT Technical Description Document. INCIDENCE DATA SPACEFLIGHT LITERATURE Spaceflight incidence was somewhat difficult to ascertain as the key paper used in previous CLIFF (Walton , 2010) was unable to be found via search. A similar incidence was calculated using instances of barotrauma

FAQs

What triggers ear and sinus barotrauma during missions?

Ear and sinus barotrauma occurs when ambient pressure changes overcome the enclosed pressure equalization capacity in gases trapped within the ear and sinus cavities, most notably during EVA-related pressurization and depressurization events.

Why is per-crewmember incidence important in the model?

The document specifies implementing incidence on a per-crewmember basis: if multiple crewmembers experience the same EVA pressure change, each experience is treated as a separate at-risk event.

How were incidence values derived for the overall estimate?

Overall incidence uses Bayesian posterior calculations based on inflight experience of 48 events over 467 person-EVAs with an uninformative prior, summarized with a Beta distribution and corresponding mean and standard deviation.

Sep 23, 2026

Uploaded by Angel