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Aerospace Medicine and Human Performance Aug 2019Establishing animal models of ear barotrauma (EB) to provide evaluation criteria for Eustachian tube dysfunction. Using expansive sponges, 70 rabbits' right pharyngeal...
Establishing animal models of ear barotrauma (EB) to provide evaluation criteria for Eustachian tube dysfunction. Using expansive sponges, 70 rabbits' right pharyngeal openings of the auditory tubes were blocked to cause dysfunction in the right Eustachian tubes. The right tympanic cavities of 65 rabbits were the Model Group (Subgroups 1-13) and these rabbits' left tympanic cavities were the Nonblockage Group. Hypobaric chamber tests (HCTs) at various vertical speeds (100 m · s, 75 m · s, 50 m · s, and 15 m · s) and altitudes (13,123 ft and 6562 ft) were conducted. The remaining five rabbits' right tympanic cavities were the Control Group and no HCTs were conducted. After HCTs, observations were made on rabbits' behavioral changes, oto-endoscope and tympanometry results, and pathological changes of the tympanic mucosae. 1) Rabbits in Subgroups 1-12 demonstrated EB, while Subgroup 13 and the Control Group did not. 2) Histopathology showed EB caused by rapid ascent/descent at 100 m · s was more severe than that of 75 m · s and 50 m · s ( < 0.01), and that there were no significant differences in EB caused by rapid ascent/descent at 75 m · s and 50 m · s ( > 0.05). There were no significant differences in pathological injuries at the altitudes of 6562 ft and 13,123 ft ( > 0.05). 3) Based on tympanic membrane structures, tympanometry, and histopathological results, rabbits' EB can be classified into mild, moderate, and severe. EB's dynamic models could be established through HCTs on rabbits with Eustachian tube dysfunction.
Topics: Acoustic Impedance Tests; Altitude; Animals; Barotrauma; Disease Models, Animal; Eustachian Tube; Humans; Male; Rabbits
PubMed: 31331419
DOI: 10.3357/AMHP.5167.2019 -
Undersea & Hyperbaric Medicine :... 2021Decompression sickness (DCS, "bends") is caused by formation of bubbles in tissues and/or blood when the sum of dissolved gas pressures exceeds ambient pressure...
Decompression sickness (DCS, "bends") is caused by formation of bubbles in tissues and/or blood when the sum of dissolved gas pressures exceeds ambient pressure (supersaturation). This may occur when ambient pressure is reduced during any of the following: ascent from a dive; depressurization of a hyperbaric chamber; rapid ascent to altitude in an unpressurized aircraft or hypobaric chamber; loss of cabin pressure in an aircraft; and during space walks.
Topics: Altitude; Decompression Sickness; Diving; First Aid; Humans; Hyperbaric Oxygenation; Time-to-Treatment
PubMed: 33975411
DOI: No ID Found -
European Annals of Otorhinolaryngology,... Nov 2020
Topics: Barotrauma; Diving; Humans; Orbital Diseases; Pain
PubMed: 32335000
DOI: 10.1016/j.anorl.2020.03.011 -
Undersea & Hyperbaric Medicine :... 2022Decompression sickness (DCS) is a known complication of scuba diving. DCS occurs when bubbles are formed as pressure is reduced during and after ascent from a dive,...
Decompression sickness (DCS) is a known complication of scuba diving. DCS occurs when bubbles are formed as pressure is reduced during and after ascent from a dive, following inert gas uptake during the dive. The bubbles cause inflammation and hypoxia. The definitive treatment for decompression sickness is hyperbaric oxygen therapy. We present a case of a healthy 16-year-old male who presented with decompression sickness and an incidental pulmonary cyst discovered by chest CT, likely congenital. The patient was successfully treated with U.S. Navy Treatment Table 6 (TT6) for his decompression sickness, but he continued to have chest pain, requiring hospitalization and consultation with pediatric pulmonology and cardiothoracic surgery from the cyst. Three years later he complained of chest pain with changes in altitude. Chest CT showed persistence of this cyst, and additional cysts. Case conference with pulmonologists and chest radiologist could not offer a definite etiology without lung biopsy, felt to not be indicated. We believe that the changes in pressure/volumes during the dives and TT6 exacerbated his pulmonary cyst.
Topics: Adolescent; Chest Pain; Child; Cysts; Decompression; Decompression Sickness; Diving; Humans; Hyperbaric Oxygenation; Male
PubMed: 36001561
DOI: No ID Found -
Prehospital and Disaster Medicine Aug 2022Blast polytrauma is among the most serious mechanisms of injury confronted by medical providers. There are currently no specific studies or guidelines that define risk... (Meta-Analysis)
Meta-Analysis Review
INTRODUCTION
Blast polytrauma is among the most serious mechanisms of injury confronted by medical providers. There are currently no specific studies or guidelines that define risk factors for mortality in the context of pediatric blast injuries or describe pediatric blast injury profiles.
OBJECTIVE
The objectives of this study were to evaluate risk factors for pediatric mortality and to describe differences in injury profiles between explosions related to terrorism versus unrelated to terrorism within the pediatric population.
METHODS
A PRISMA systematic review and meta-analysis was performed where articles published from the years 2000-2021 were extracted from PubMed. Mortality and injury profile data were extracted from articles that met inclusion criteria. A bivariant unadjusted odds ratio (OR) analysis was performed to establish protective and harmful factors associated with mortality and to describe the injury profiles of blasts related to terrorism. Statistical significance was established at P < .05.
RESULTS
Thirty-eight articles were included and described a total of 222,638 unique injuries. Factors associated with increased mortality included if the explosion was related to terrorism (OR = 32.73; 95% CI, 28.80-37.21; P < .05) and if the explosion involved high-grade explosives utilized in the Global War on Terror ([GWOT] OR = 1.28; 95% CI, 1.04-1.44; P < .05). Factors associated with decreased mortality included if the patient was resuscitated in a North Atlantic Treaty Organization (NATO)-affiliated combat trauma hospital (OR = 0.48; 95% CI, 0.37-0.62; P < .05); if the explosive was fireworks (OR = 3.20×10-5; 95% CI, 2.00×10-6-5.16×10-4; P < .05); and if the explosion occurred in the United States (OR = 2.40×10-5; 95% CI, 1.51×10-6-3.87×10-4; P < .05). On average, victims of explosions related to terrorism were 10.30 years old (SD = 2.73) with 68.96% (SD = 17.58%) of victims reported as male. Comparison of victims of explosions related to terrorism revealed a higher incidence of thoracoabdominal trauma (30.2% versus 8.6%), similar incidence of craniocerebral trauma (39.5% versus 43.1%), and lower incidence of extremity trauma (31.8% versus 48.3%) compared to victims of explosions unrelated to terrorism.
CONCLUSION
Explosions related to terrorism are associated with increased mortality and unique injury profiles compared to explosions unrelated to terrorism in the pediatric population. Such findings are important for optimizing disaster medical education of pediatric providers in preparation for and management of acute sequelae of blast injuries-terror-related and otherwise.
Topics: Blast Injuries; Child; Explosions; Hospitals; Humans; Male; Multiple Trauma; Terrorism
PubMed: 35603691
DOI: 10.1017/S1049023X22000747 -
Military Medicine Mar 2023Occupational exposure to repetitive, low-level blasts in military training and combat has been tied to subconcussive injury and poor health outcomes for service members....
INTRODUCTION
Occupational exposure to repetitive, low-level blasts in military training and combat has been tied to subconcussive injury and poor health outcomes for service members. Most low-level blast studies to date have focused on explosive breaching and firing heavy weapon systems; however, there is limited research on the repetitive blast exposure and physiological effects that mortarmen experience when firing mortar weapon systems. Motivated by anecdotal symptoms of mortarmen, the purpose of this paper is to characterize this exposure and its resulting neurocognitive effects in order to provide preliminary findings and actionable recommendations to safeguard the health of mortarmen.
MATERIALS AND METHODS
In collaboration with the U.S. Army Rangers at Fort Benning, blast exposure, symptoms, and pupillary light reflex were measured during 3 days of firing 81 mm and 120 mm mortars in training. Blast exposure analysis included the examination of the blast overpressure (BOP) and cumulative exposure by mortarman position, as well as comparison to the 4 psi safety threshold. Pupillary light reflex responses were analyzed with linear mixed effects modeling. All neurocognitive results were compared between mortarmen (n = 11) and controls (n = 4) and cross-compared with blast exposure and blast history.
RESULTS
Nearly 500 rounds were fired during the study, resulting in a high cumulative blast exposure for all mortarmen. While two mortarmen had average BOPs exceeding the 4 psi safety limit (Fig. 2), there was a high prevalence of mTBI-like symptoms among all mortarmen, with over 70% experiencing headaches, ringing in the ears, forgetfulness/poor memory, and taking longer to think during the training week (n ≥ 8/11). Mortarmen also had smaller and slower pupillary light reflex responses relative to controls, with significantly slower dilation velocity (P < 0.05) and constriction velocity (P < 0.10).
CONCLUSION
Mortarmen experienced high cumulative blast exposure coinciding with altered neurocognition that is suggestive of blast-related subconcussive injury. These neurocognitive effects occurred even in mortarmen with average BOP below the 4 psi safety threshold. While this study was limited by a small sample size, its results demonstrate a concerning health risk for mortarmen that requires additional study and immediate action. Behavioral changes like ducking and standing farther from the mortar when firing can generally help reduce mortarmen BOP exposure, but we recommend the establishment of daily cumulative safety thresholds and daily firing limits in training to reduce cumulative blast exposure, and ultimately, improve mortarmen's quality of life and longevity in service.
Topics: Humans; Military Personnel; Quality of Life; Explosions; Blast Injuries
PubMed: 34557921
DOI: 10.1093/milmed/usab394 -
Journal of Neurotrauma Nov 2022
Topics: Humans; Blast Injuries; Organoids; Brain; Brain Injuries; Learning
PubMed: 36321850
DOI: 10.1089/neu.2022.29132.editorial -
Diving and Hyperbaric Medicine Sep 2019There are few issues that generate as much confusion in diving medicine as the nomenclature of bubble-induced dysbaric disease. Prior to the late 1980s, the diagnosis...
There are few issues that generate as much confusion in diving medicine as the nomenclature of bubble-induced dysbaric disease. Prior to the late 1980s, the diagnosis 'decompression sickness' (DCS) was invoked for symptoms presumed to arise as a consequence of bubble formation from dissolved inert gas during or after decompression. These bubbles were known to form within tissues, and also to appear in the venous blood (presumably after forming in tissue capillaries). A second diagnosis, 'arterial gas embolism' (AGE) was invoked for symptoms presumed to arise when bubbles were introduced directly to the arterial circulation as a consequence of pulmonary barotrauma. This approach was predicated on an assumption that the underlying pathophysiology could usually be inferred from the nature and tempo of resulting symptoms. DCS was considered to exhibit a slower more progressive onset, symptoms were protean (including pain, rash, paraesthesias, subcutaneous swelling, and neurological symptoms), and the neurological manifestations were mainly attributable to spinal cord or inner ear involvement. In contrast, AGE was considered to exhibit a more precipitous onset (often immediately on surfacing), and the principal manifestation was stroke-like focal neurological impairment suggestive of cerebral involvement. In 1989 an association between a large persistent ('patent') foramen ovale (PFO) and serious neurological DCS was independently reported by two groups, and subsequently corroborated for neurological, inner ear, and cutaneous DCS by multiple studies. The assumed pathophysiological role of a PFO in this setting was to allow bubbles formed from inert gas in the venous blood to avoid removal in the pulmonary circulation and to enter the arterial circulation. These bubbles could then pass to the microcirculation of vulnerable target tissues where inward diffusion of supersaturated inert gas from the surrounding tissue could cause them to grow. This emergence of 'arterialisation' of venous bubbles as an important vector of harm in some forms of DCS resulted in a challenge to the use of traditional 'DCS/AGE' terminology. It was suggested that very early onset of cerebral symptoms after diving could be explained not only by arterial bubbles introduced by pulmonary barotrauma, but also by venous bubbles crossing a PFO into the arterial circulation. Moreover, once venous bubbles had entered the arterial circulation they were then technically 'arterial gas emboli'; thus creating confusion with arterial gas emboli from pulmonary barotrauma. To many commentators, it made little sense to use diagnostic labels (DCS and AGE) that implied a particular pathophysiology when the two disorders might be difficult to tell apart, and had mechanistic processes in common. An alternative approach derived at a UHMS workshop in 1991 was to shift from nomenclature that implied a particular pathophysiology, to a descriptive system that lumped both DCS and AGE together under the label "decompression illness" (DCI). Using this system, terms to describe the organ system(s) involved and the progression of symptoms were applied. For example, a diver with worsening upper arm pain after a dive could be suffering 'progressive musculoskeletal DCI'; and a diver who lost consciousness immediately on surfacing but regained consciousness minutes later would be considered to be suffering 'remitting cerebral DCI'. Classifying cases in this manner made considerable sense at a clinical level, particularly given that there was an emerging consensus that manifestations of DCS and AGE that potentially overlapped did not require different approaches to recompression treatment. This descriptive classification of bubble-induced dysbaric disease gained substantial traction in the community, though not always with a full appreciation by users of the intended nuances of its application. Indeed, it became increasingly common over time to see the terms DCS and DCI used interchangeably; for example, authors using the term DCI to specifically infer the consequences of bubble formation from dissolved gas. This highlights one of the shortcomings of the DCI terminology: it becomes confusing when discussing dysbaric disease at a theoretical or experimental level when the nature of the insult is known or there is a specific intent to discuss bubble formation either from dissolved gas or from pulmonary barotrauma. The potential for confusion between mechanisms and manifestations of DCS and AGE as one of the principle drivers for adopting the DCI terminology deserves further discussion. It is tempting to suggest that if venous bubbles cross a PFO into the arterial blood then any resulting symptoms should be considered a manifestation of 'AGE'. However, there seems little sense in re-naming the primary pathophysiological event (DCS caused by bubble formation from inert gas) just because the bubbles have distributed elsewhere; especially using a name that commonly infers a completely different primary event (bubble formation from pulmonary barotrauma). Moreover, there are grounds for suggesting that these two processes may not be as difficult to distinguish as previously believed. Venous inert gas bubbles are small, and of a similar size distribution to those used as bubble contrast during PFO testing. Decades of experience in testing thousands of divers (and other patients) for PFO using bubble-contrast echocardiograpy have shown that even when strongly positive (that is, large showers of bubbles enter the arterial circulation), symptoms of any sort are very rare. There are sporadic reports of evanescent visual or cerebral symptoms, but (to this author's knowledge) reports of the focal or multifocal cerebral infarctions that can be caused by large arterial bubbles introduced iatrogenically or by pulmonary barotrauma are lacking. One could argue that in the context of PFO testing the brain is not supersaturated with inert gas (which might cause small arterial bubbles to grow), but being such a 'fast tissue' nor is it likely to be after diving. Thus, while sustained showers of small inert gas bubbles crossing a PFO after diving appeal as a plausible cause of transient visual symptoms or dysexecutive syndromes after diving, they are less likely to be the cause of dramatic stroke-like events occurring early after surfacing. In the final edition of Bennett and Elliott it was suggested that one editorial approach to the terminology conundrum would be to utilise the traditional terminology (DCS and AGE) when referring specifically to the pathophysiology and manifestations of bubble formation from dissolved inert gas or pulmonary barotrauma respectively, and to utilise the descriptive (DCI) terminology in clinical discussions when a collective term is useful, or when discussing individual patients where there is either ambiguity about pathophysiology or no need to attempt a distinction. Diving and Hyperbaric Medicine recommends a similar approach. The journal is reluctant to attempt to generate or apply hard 'rules' in relation to terminology of bubble-induced dysbaric disease, but we strongly discourage use of the term 'arterial gas emboli(ism)' to characterise venous inert gas bubbles that cross a right-to-left shunt such as a PFO. The pathophysiological consequences of bubble formation from dissolved inert gas should be regarded as decompression sickness (DCS). There is an expectation that authors are cognisant of the above issues and attempt to adopt terminology that reflects these considerations and best suits the circumstances of their manuscript.
Topics: Decompression; Decompression Sickness; Diving; Embolism, Air; Foramen Ovale, Patent; Humans
PubMed: 31523788
DOI: 10.28920/dhm49.3.152-153 -
Rozhledy V Chirurgii : Mesicnik... 2023The incidence of explosions in large agglomerations is high even during peacetime and continues rising. Blast syndrome injuries are complex, with shock wave causing... (Review)
Review
The incidence of explosions in large agglomerations is high even during peacetime and continues rising. Blast syndrome injuries are complex, with shock wave causing severe injuries of multiple organ systems. In situations with large numbers of injured persons, effective triage allows an early diagnosis and treatment of the highest number of victims. Treatment is challenging, and potentially conflicting therapeutic goals may alternate. This review provides an overview of the pathophysiology of blast injuries, current diagnostic algorithms and therapeutic procedures.
Topics: Humans; Blast Injuries; Explosions; Incidence
PubMed: 38286652
DOI: 10.33699/PIS.2023.102.6.236-243 -
Aerospace Medicine and Human Performance May 2022Barometric pressure variation during dives may induce barodontalgia and barotrauma. Barodontalgia refers to oral pain resulting from a change in ambient pressure. The...
Barometric pressure variation during dives may induce barodontalgia and barotrauma. Barodontalgia refers to oral pain resulting from a change in ambient pressure. The aim of this study was to investigate the occurrence of barodontalgia and dental barotrauma among French civilian scuba divers. A nationwide cross-sectional internet-based survey was conducted among French scuba divers over 18 yr of age registered by the French Federation of Underwater Sports (FFESSM). The online questionnaire was distributed from October to December 2020. It contained questions regarding general characteristics of participants, barodontalgia and dental barotrauma occurrences, and relationship of the diver with his/her dentist. There were 684 scuba divers (65.4% men; aged 48 ± 12 yr) who participated in the study. Barodontalgia was reported by 18.7%, with some respondents reporting more than one episode. Most barodontalgia affected posterior (81.2%) and upper teeth (55.2%) with dental filling (50.0%). At least one dental barotrauma was reported by 10.1% of respondents, including mainly loss or fracture of a dental filling (4.2%). The occurrence of dental barotrauma was significantly higher among men (12.3%) than women (5.9%) and increased significantly with the age, the years of diving and the diving qualification. Information should be provided to divers on the importance of routine dental checkups.
Topics: Atmospheric Pressure; Barotrauma; Cross-Sectional Studies; Diving; Female; Humans; Male; Toothache
PubMed: 35551726
DOI: 10.3357/AMHP.6045.2022