INTRODUCTION: Most U.S. Navy, but few U.S. Air Force, tactical jets use safety pressure (SP) regulators. SP effects have been studied only with confounding differences in regulator design. We compared a CRU-103 SP regulator to a CRU-103 with SP removed. The hypothesis was that SP does not alter breathing, only shifts pressure more positive.

METHODS: Inspiratory flows and mask and hose pressures were measured in 24 subjects (29 for speech at rest, 31 for lung volumes) who breathed in counterbalanced order from both regulators while blind to SP condition.

RESULTS: Both were easy to breathe. Neither was preferred overall. Between regulators, end-expiratory lung volume did not differ. SP stabilized hose pressure and favored inspiration: without speech, hose pressure swings were significantly lower (rest: 25%, exercise: 33%), as were inspiratory work of breathing at rest (33%) and peak inspiratory flow magnitude (rest: 14%; exercise: 11%). Waveforms showed interactions of mask valves and SP at the start and end of expiration. Mask leaks with SP activated the regulator during speech.

DISCUSSION: SP as implemented in the CRU-103 causes mostly subtle differences in pressures and flows. The sensed difference during expiration may result from the initial large pressure gradient for expiratory flow.

Shykoff BE, French DC, Warkander DE, Robinson FE. Safety pressure effects in a mechanical demand regulator. Aerosp Med Hum Perform. 2025; 96(7):547–555.

BACKGROUND: Sinus barotrauma, or aerosinusitis, occurs during rapid atmospheric changes in aviation, primarily affecting the frontal sinus. Mucosal swelling from a cold or allergic rhinitis (AR) can obstruct pressure equalization, leading to mucosal tears, cranial pain, and nasal bleeding. Despite its significance in aerospace medicine, high-quality imaging, nasal endoscopy, long-term outcomes, and the impact of AR management on sinus barotrauma remain inadequately documented in the literature.

CASE REPORT: A 29-yr-old healthy male healthcare provider experienced severe frontal sinus barotrauma during aircraft descent, presenting with intense frontal headache, ocular pain, and left epistaxis, with head computed tomography revealing a fully opacified left frontal sinus. Despite experiencing persistent severe AR symptoms daily, he had never been diagnosed or treated for AR, and his symptoms worsened during the flight. The clinical presentations and image findings suggested a diagnosis of frontal sinus barotrauma. His initial treatment included oral decongestants, antihistamines, and acetaminophen. Remarkably, follow-up computed tomography/magnetic resonance images over 2 wk, 1 mo, and 1 yr demonstrated the spontaneous resorption of the submucosal hemorrhage in the frontal sinus. Furthermore, though concurrently diagnosed with perennial AR due to house dust mite and cat fur sensitization, the patient’s effective pharmacological management of AR symptoms led to an uneventful flight 1 yr later.

DISCUSSION: This case demonstrates that submucosal hemorrhages in the affected sinus generally resolve spontaneously within a year. Also, it highlights the critical need for diagnosing and managing sinonasal disorders in symptomatic individuals before flights to prevent sinus barotrauma.

Park MJ, Kang SJ, Kim GT, Kim S. Frontal sinus barotrauma in an airliner passenger with undiagnosed allergic rhinitis. Aerosp Med Hum Perform. 2025; 96(7):581–585.

BACKGROUND: Deep vein thrombosis (DVT) is a morbid disease that potentially has lethal results, with even further professional ramifications in the aviation community. There are only a few reported cases on outcomes of fliers who developed DVT. As such, more research is needed to assist the aeromedical community in identifying high-risk individuals so that counseling and preventative measures are administered to avoid harmful outcomes.

CASE REPORT: We present a 34-yr-old woman with several pre-existing comorbidities who developed ipsilateral DVTs in her lower extremity while in Oman that required medical evacuation back stateside. Days prior to her long-haul flight overseas, she presented to the local emergency department with right lower extremity DVT similar to a prior one she experienced. A week later, while departing the continental United States, she was evaluated by Emergency Medical Technicians for painful ambulation. After being symptomatic for over a week in country, she was admitted to a local hospital where formal diagnosis was made.

DISCUSSION: Aviators are not as familiar with the risks and consequences of thrombus formation. This case highlights several key points, such as a thorough medical clearance process in conjunction with closed loop communication. A history of DVT with additional susceptibilities requires in-depth education prior to long distance travel. A thorough record review should be conducted on a high-risk servicemember to ensure medical optimization. When making the decision to use medical evacuation, risk stratification must be implemented early to ensure safe return.

Cheng MT, Middel BL, Anderson KD. Recurrent deep vein thromboses in an active-duty aviator. Aerosp Med Hum Perform. 2025; 96(7):586–589.

The aviation industry is exploring possibilities to operate extended long-haul flights with two pilots in the cockpit during critical flight phases and a single pilot flying during cruise flight while the other pilot is sleeping. This Extended Minimum Crew Operations (eMCO) concept raises important aeromedical concerns: 1) a two-pilot cockpit is considered a main safety risk-mitigating factor and eMCO would therefore necessitate a new aeromedical risk assessment concept; 2) sensors and algorithms for monitoring physical and/or cognitive incapacitation are not available or insufficiently reliable; 3) scientific data of augmented long-haul flights is not valid for predicting effects of monotony and boredom or in-flight sleep and sleep inertia on alertness during eMCO cruise-flight; and 4) medical conditions regarding urination, defecation, or menstruation may cause an unscheduled visit to the toilet of the single pilot flying during cruise flight, who then has to request the resting pilot to take over the controls.

Simons R, Maher D, Vermeiren R, Wagstaff AS. Aeromedical concerns about extended minimum crew operations. Aerosp Med Hum Perform. 2025; 96(7):590–592.