Barotrauma and Arterial Gas Embolism: A Diving Emergencies Simulation Case for Emergency Medicine Residents

Chest CT scan for the screening of air anomalies at risk of pulmonary barotrauma for the initial medical assessment of fitness to dive in a military population

Introduction: The presence of intra-pulmonary air lesions such as cysts, blebs and emphysema bullae, predisposes to pulmonary barotrauma during pressure variations, especially during underwater diving activities. These rare accidents can have dramatic consequences. Chest radiography has long been the baseline examination for the detection of respiratory pathologies in occupational medicine. It has been replaced since 2018 by the thoracic CT scan for military diving fitness in France. The objective of this work was to evaluate the prevalence of the pulmonary abnormalities of the thoracic CT scan, and to relate them to the characteristics of this population and the results of the spirometry.

Methods: 330 records of military diving candidates who underwent an initial assessment between October 2018 and March 2021 were analyzed, in a single-center retrospective analysis. The following data were collected: sex, age, BMI, history of respiratory pathologies and smoking, treatments, allergies, diving practice, results of spirometry, reports of thoracic CT scans, as well as fitness decision.

Results: The study included 307 candidates, mostly male, with a median age of 25 years. 19% of the subjects had abnormal spirometry. We identified 25% of divers with CT scan abnormalities. 76% of the abnormal scans were benign nodules, 26% of which measured 6 mm or more. Abnormalities with an aerial component accounted for 13% of the abnormal scans with six emphysema bullae, three bronchial dilatations and one cystic lesion. No association was found between the presence of nodules and the general characteristics of the population, whereas in six subjects emphysema bullae were found statistically associated with active smoking or abnormal spirometry results.

Conclusion: The systematic performance of thoracic CT scan in a young population free of pulmonary pathology revealed a majority of benign nodules. Abnormalities with an aerial component are much less frequent, but their presence generally leads to a decision of unfitness. These results argue in favor of a systematic screening of aeric pleuro-pulmonary lesions during the initial assessment for professional divers.

Dysbarism: An Overview of an Unusual Medical Emergency

Dysbarism is a general term which includes the signs and symptoms that can manifest when the body is subject to an increase or a decrease in the atmospheric pressure which occurs either at a rate or duration exceeding the capacity of the body to adapt safely. In the following review, we take dysbarisms into account for our analysis. Starting from the underlying physical laws, we will deal with the pathologies that can develop in the most frequently affected areas of the body, as the atmospheric pressure varies when acclimatization fails. Manifestations of dysbarism range from itching and minor pain to neurological symptoms, cardiac collapse, and death. Overall, four clinical pictures can occur: decompression illness, barotrauma, inert gas narcosis, and oxygen toxicity. We will then review the clinical manifestations and illustrate some hints of therapy. We will first introduce the two forms of decompression sickness. In the next part, we will review the barotrauma, compression, and decompression. The last three parts will be dedicated to gas embolism, inert gas narcosis, and oxygen toxicity. Such an approach is critical for the effective treatment of patients in a hostile environment, or treatment in the emergency room after exposure to extreme physical or environmental factors.

Case Series of Arterial Gas Embolism Incidents in U.S. Navy Pressurized Submarine Escape Training From 2018 to 2019

The goal of Pressurized Submarine Escape Training (PSET) is to prepare future submariners for the physical and mental challenges of escaping a disabled submarine and promote proper handling of the Beaufort Ltd Mk 11 Submarine Escape and Immersion Equipment suit. Training participants are only permitted to enter PSET after strict health screening protocols have been met to optimize trainees' safety. Before PSET, trainees are given detailed, one-on-one instruction on proper ascent mechanics by specially trained Navy Dive instructors. Since the reinstatement of PSET by the U.S. Navy, four incidents of arterial gas embolism (AGE) have occurred in submarine trainees with a 10-year period (2009-2019). Of these four incidents, three were observed within a couple months of each other from 2018 to 2019. A comprehensive review of AGE history, epidemiology, dive physiology, pathophysiology, and management was completed. Prompted by the recent incidents relative to the low reported incidence rate of AGE in historical PSET training, reported potential risk factors were compared with better understand potential etiologies of AGE in already medically screened individuals. Risks and benefits of PSET were listed, compared, and analyzed. The relative safety and cost effectiveness of this rigorous form of training was reconfirmed.

Raising rare disease awareness using red flags, role play simulation and patient educators: results of a novel educational workshop on Raynaud phenomenon and systemic sclerosis

BACKGROUND

As lack of awareness of rare diseases (RDs) among healthcare professionals results in delayed diagnoses, there is a need for a more efficient approach to RD training during academic education. We designed an experimental workshop that used role-play simulation with patient educators and focused on teaching "red flags" that should raise the suspicion of an RD when faced with a patient with frequently encountered symptoms. Our objective was to report our experience, and to assess the improvement in learners' knowledge and the satisfaction levels of the participants.

RESULTS

The workshop consisted of 2 simulated consultations that both started with the same frequent symptom (Raynaud phenomenon, RP) but led to different diagnoses: a frequent condition (idiopathic RP) and an RD (systemic sclerosis, SSc). In the second simulated consultation, the role of the patient was played by a patient educator with SSc. By juxtaposing 2 seemingly similar situations, the training particularly highlighted the elements that help differentiate SSc from idiopathic RP. When answering a clinical case exam about RP and SSc, students that had participated in the workshop had a higher mean mark than those who had not (14 ± 3.7 vs 9.6 ± 5.5 points out of 20, p = 0.001). Participants mostly felt "very satisfied" with this training (94%), and "more comfortable" about managing idiopathic RP and SSc (100%). They considered the workshop "not very stressful" and "very formative" (both 71%). When asked about the strengths of this training, they mentioned the benefits of being put in an immersive situation, allowing a better acquisition of practical skills and a more interactive exchange with teachers, as well as the confrontation with a real patient, leading to a better retention of semiological findings and associating a relational component with this experience.

CONCLUSIONS

Through the use of innovative educational methods, such as role-play simulation and patient educators, and by focusing on teaching "red flags", our workshop successfully improved RP and SSc learning in a way that satisfied students. By modifying the workshop's scenarios, its template can readily be applied to other clinical situations, making it an interesting tool to teach other RDs.