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Diving and Hyperbaric Medicine Jun 2024Inhalation of high concentrations of carbon dioxide (CO₂) at atmospheric pressure can be toxic with dose-dependent effects on the cardiorespiratory system or the... (Review)
Review
INTRODUCTION
Inhalation of high concentrations of carbon dioxide (CO₂) at atmospheric pressure can be toxic with dose-dependent effects on the cardiorespiratory system or the central nervous system. Exposure to both hyperbaric and hypobaric environments can result in decompression sickness (DCS). The effects of CO₂ on DCS are not well documented with conflicting results. The objective was to review the literature to clarify the effects of CO₂ inhalation on DCS in the context of hypobaric or hyperbaric exposure.
METHODS
The systematic review included experimental animal and human studies in hyper- and hypobaric conditions evaluating the effects of CO₂ on bubble formation, denitrogenation or the occurrence of DCS. The search was based on MEDLINE and PubMed articles with no language or date restrictions and also included articles from the underwater and aviation medicine literature.
RESULTS
Out of 43 articles, only 11 articles were retained and classified according to the criteria of hypo- or hyperbaric exposure, taking into account the duration of CO₂ inhalation in relation to exposure and distinguishing experimental work from studies conducted in humans.
CONCLUSIONS
Before or during a stay in hypobaric conditions, exposure to high concentrations of CO₂ favors bubble formation and the occurrence of DCS. In hyperbaric conditions, high CO₂ concentrations increase the occurrence of DCS when exposure occurs during the bottom phase at maximum pressure, whereas beneficial effects are observed when exposure occurs during decompression. These opposite effects depending on the timing of exposure could be related to 1) the physical properties of CO₂, a highly diffusible gas that can influence bubble formation, 2) vasomotor effects (vasodilation), and 3) anti-inflammatory effects (kinase-nuclear factor and heme oxygenase-1 pathways). The use of O₂-CO₂ breathing mixtures on the surface after diving may be an avenue worth exploring to prevent DCS.
Topics: Animals; Humans; Atmospheric Pressure; Carbon Dioxide; Decompression Sickness; Diving
PubMed: 38870953
DOI: 10.28920/dhm54.2.110-119 -
European Archives of... May 2024Determine the prevalence of otological symptoms and tympanic membrane perforation, healing rates of tympanic membrane perforation with surgical and conservative... (Review)
Review
PURPOSE
Determine the prevalence of otological symptoms and tympanic membrane perforation, healing rates of tympanic membrane perforation with surgical and conservative management, and hearing function in civilian victims of terrorist explosions.
METHODS
A systematic review was conducted with searches on Medline, Embase, EMCare and CINAHL for publications between the 1st January 1945 and 26th May 2023. Studies with quantitative data addressing our aims were included. This review is registered with PROSPERO: CRD42020166768. Among 2611 studies screened, 18 studies comprising prospective and retrospective cohort studies were included.
RESULTS
The percentage of eardrums perforated in patients admitted to hospital, under ENT follow up and attending the emergency department is 69.0% (CI 55.5-80.5%), 38.7% (CI 19.0-63.0%, I 0.715%) and 21.0% (CI 11.9-34.3%, I 0.718%) respectively. Perforated eardrums heal spontaneously in 62.9% (CI 50.4-73.8%, I 0.687%) of cases and in 88.8% (CI 75.9-96.3%, I 0.500%) of cases after surgery. Common symptoms present within one month of bombings are tinnitus 84.7% (CI 70.0-92.9%, I 0.506%), hearing loss 83.0% (CI 64.5-92.9%, I 0.505%) and ear fullness 59.7% (CI 13.4-93.4%, I 0.719). Symptomatic status between one and six months commonly include no symptoms 57.5% (CI 46.0-68.3%), hearing loss 35.4% (CI 21.8-51.8%, I 0.673%) and tinnitus 15.6% (CI 4.9-40.0%, I 0.500%). Within one month of bombings, the most common hearing abnormality is sensorineural hearing loss affecting 26.9% (CI 16.9-40.1%, I 0.689%) of ears 43.5% (CI 33.4-54.2%, I 0.500) of people.
CONCLUSION
Tympanic membrane perforation, subjective hearing loss, tinnitus, ear fullness and sensorineural hearing loss are common sequelae of civilian terrorist explosions.
Topics: Humans; Tympanic Membrane Perforation; Tinnitus; Explosions; Retrospective Studies; Blast Injuries; Prospective Studies; Hearing Loss; Hearing Loss, Sensorineural; Deafness; Terrorism
PubMed: 38189970
DOI: 10.1007/s00405-023-08393-z -
The Cochrane Database of Systematic... Aug 2023This is the third update of the original Cochrane Review published in July 2005 and updated previously in 2012 and 2016. Cancer is a significant global health issue.... (Review)
Review
BACKGROUND
This is the third update of the original Cochrane Review published in July 2005 and updated previously in 2012 and 2016. Cancer is a significant global health issue. Radiotherapy is a treatment modality for many malignancies, and about 50% of people having radiotherapy will be long-term survivors. Some will experience late radiation tissue injury (LRTI), developing months or years following radiotherapy. Hyperbaric oxygen therapy (HBOT) has been suggested as a treatment for LRTI based on the ability to improve the blood supply to these tissues. It is postulated that HBOT may result in both healing of tissues and the prevention of complications following surgery and radiotherapy.
OBJECTIVES
To evaluate the benefits and harms of hyperbaric oxygen therapy (HBOT) for treating or preventing late radiation tissue injury (LRTI) compared to regimens that excluded HBOT.
SEARCH METHODS
We used standard, extensive Cochrane search methods. The latest search date was 24 January 2022.
SELECTION CRITERIA
We included randomised controlled trials (RCTs) comparing the effect of HBOT versus no HBOT on LRTI prevention or healing.
DATA COLLECTION AND ANALYSIS
We used standard Cochrane methods. Our primary outcomes were 1. survival from time of randomisation to death from any cause; 2. complete or substantial resolution of clinical problem; 3. site-specific outcomes; and 4.
ADVERSE EVENTS
Our secondary outcomes were 5. resolution of pain; 6. improvement in quality of life, function, or both; and 7. site-specific outcomes. We used GRADE to assess certainty of evidence.
MAIN RESULTS
Eighteen studies contributed to this review (1071 participants) with publications ranging from 1985 to 2022. We added four new studies to this updated review and evidence for the treatment of radiation proctitis, radiation cystitis, and the prevention and treatment of osteoradionecrosis (ORN). HBOT may not prevent death at one year (risk ratio (RR) 0.93, 95% confidence interval (CI) 0.47 to 1.83; I = 0%; 3 RCTs, 166 participants; low-certainty evidence). There is some evidence that HBOT may result in complete resolution or provide significant improvement of LRTI (RR 1.39, 95% CI 1.02 to 1.89; I = 64%; 5 RCTs, 468 participants; low-certainty evidence) and HBOT may result in a large reduction in wound dehiscence following head and neck soft tissue surgery (RR 0.24, 95% CI 0.06 to 0.94; I = 70%; 2 RCTs, 264 participants; low-certainty evidence). In addition, pain scores in ORN improve slightly after HBOT at 12 months (mean difference (MD) -10.72, 95% CI -18.97 to -2.47; I = 40%; 2 RCTs, 157 participants; moderate-certainty evidence). Regarding adverse events, HBOT results in a higher risk of a reduction in visual acuity (RR 4.03, 95% CI 1.65 to 9.84; 5 RCTs, 438 participants; high-certainty evidence). There was a risk of ear barotrauma in people receiving HBOT when no sham pressurisation was used for the control group (RR 9.08, 95% CI 2.21 to 37.26; I = 0%; 4 RCTs, 357 participants; high-certainty evidence), but no such increase when a sham pressurisation was employed (RR 1.07, 95% CI 0.52 to 2.21; I = 74%; 2 RCTs, 158 participants; high-certainty evidence).
AUTHORS' CONCLUSIONS
These small studies suggest that for people with LRTI affecting tissues of the head, neck, bladder and rectum, HBOT may be associated with improved outcomes (low- to moderate-certainty evidence). HBOT may also result in a reduced risk of wound dehiscence and a modest reduction in pain following head and neck irradiation. However, HBOT is unlikely to influence the risk of death in the short term. HBOT also carries a risk of adverse events, including an increased risk of a reduction in visual acuity (usually temporary) and of ear barotrauma on compression. Hence, the application of HBOT to selected participants may be justified. The small number of studies and participants, and the methodological and reporting inadequacies of some of the primary studies included in this review demand a cautious interpretation. More information is required on the subset of disease severity and tissue type affected that is most likely to benefit from this therapy, the time for which we can expect any benefits to persist and the most appropriate oxygen dose. Further research is required to establish the optimum participant selection and timing of any therapy. An economic evaluation should also be undertaken.
Topics: Humans; Hyperbaric Oxygenation; Radiation Injuries; Neoplasms; Osteoradionecrosis; Disease Progression; Pain; Barotrauma
PubMed: 37585677
DOI: 10.1002/14651858.CD005005.pub5 -
Military Medicine Aug 2023Operations Iraqi Freedom and Enduring Freedom saw higher rates of combat ocular trauma (COT) than any past U.S. conflict. The improvised explosive device, the signature...
INTRODUCTION
Operations Iraqi Freedom and Enduring Freedom saw higher rates of combat ocular trauma (COT) than any past U.S. conflict. The improvised explosive device, the signature weapon of the conflicts, as well as improved personal protective equipment and combat medical care all attributed to COT being the fourth most common injury sustained by wounded U.S. service members. This review describes the epidemiology, mechanisms, and treatment patterns and discusses the relationship of traumatic brain injuries (TBIs) to ocular injuries sustained by U.S. service members during the War on Terror.
MATERIALS AND METHODS
A mixed-methods review of the literature was conducted by extracting data from PubMed, Embase, and Cochrane research databases between December 15, 2020, and January 25, 2021, using the COVIDENCE review management software.
RESULTS
Of 827 articles for review, 50 were deemed relevant. Articles were separated using the Birmingham Eye Trauma Terminology into open globe, closed globe, mixed/injury management only, and TBI. Seventeen articles were found to discuss data pertaining to particular databases. Overall, six articles discussed open-globe injuries in the setting of overall COT with a reported rate of 38-64%. Three articles discussed closed-globe injuries in the context of overall COT with a rate of 39-47%. Numerous articles discussed the relationship between COT and TBI. Within the Walter Reed Ocular Trauma Database, 40% of patients with ocular trauma had concomitant TBI. Additionally, the visual sequelae of ocular trauma ranged from 9% to 50% among reporting studies. Other ocular injury patterns receiving attention include neuro-ophthalmic and oculoplastic injuries. By far the most common mechanism of COT was blast injury (64-84%), with improvised explosive devices (IEDs) accounting for 51-69% of ocular injuries. Among the large reporting databases, 41-45% of COT required surgical treatment with an overall enucleation rate of 12-17%.
CONCLUSIONS
The Global War on Terrorism saw an evolution in the types of ocular injuries sustained by U.S. service members compared to previous conflicts. The widespread use of IEDs led to injury patterns not encountered in previous conflicts. Weapons of today utilize blast and shrapnel as the mechanism for destruction. Sequelae such as TBIs and complicated head and neck trauma have pushed innovation in the field of ophthalmology. Improvements in medical technology and personal protective equipment have resulted in not only survival of previously life-threatening injuries, but also a greater chance of severe loss of vision. By analyzing ocular injury data from the trauma literature, improvements in education and training can lead to improvements in point-of-injury care and eye protection for the next generation of warfighters.
Topics: Humans; Visual Acuity; Eye Injuries; Brain Injuries, Traumatic; Iraq War, 2003-2011; Blast Injuries; Disease Progression; Retrospective Studies
PubMed: 35869887
DOI: 10.1093/milmed/usac226