Role of tympanocentesis in the prevention of middle ear barotrauma induced by fast buoyant ascent escape from 200 m underwater.

Introduction: We aimed to study middle ear barotrauma caused by fast compression followed by buoyant ascent escape from 200 m underwater and its effect on the auditory system, and to validate the preventive effect of tympanocentesis on middle ear barotrauma. Methods: Twenty Sprague Dawley rats were divided into two groups: rats in group A underwent a simulated fast buoyant ascent escape from a depth of 200 m, while those in group B underwent tympanocentesis before the procedure described for group A. Ear endoscopy, acoustic conductance, and auditory brainstem response (ABR) tests were conducted before and after the procedure to evaluate the severity of middle ear barotrauma and auditory function in both groups. Additionally, histopathological examination of the middle ear in both groups was conducted to evaluate the severity of middle ear barotrauma by observing submucosal haemorrhage. Results: None of the ears in either group showed any abnormalities before the experiment. In group A, middle ear barotrauma was universally observed after the simulation procedure. The tympanograms of all ears were initially type A and became type B after the procedure. Further, after the simulation, the hearing thresholds at different frequencies (4, 8, 16, 24, and 32 kHz) assessed by ABR significantly increased compared to those before the procedure. In group B, no middle ear barotrauma was observed, and the hearing threshold at each frequency did not change significantly compared with post-puncturing. After dissecting the middle ear, gross pathological observations were consistent with the above results. Microscopically, blood accumulation and submucosal haemorrhage in the middle ear cavity were observed in group A but not in group B. Conclusions: Fast buoyant ascent from 200 m underwater can cause middle ear barotrauma, resulting in hearing loss. Tympanic membrane puncture can effectively prevent middle ear barotrauma caused by the rapid buoyant ascent escape procedure.

Paediatric donor lung preservation using Paragonix BAROguard.

Paediatric lung transplantation is a lifesaving option in selected patients with end-stage lung disease. Favourable long-term outcomes are limited by impaired mucus clearance, increased risk of infection resulting from immunosuppression, and chronic lung allograft dysfunction. Organ preservation techniques play an important role in the quality of donated organs. Barotrauma to donated lungs may arise from a combination of excessive recruitment manoeuvres and altitude change during air transportation. The Paragonix BAROguard Donor Lung Preservation System is an FDA-approved advanced organ recovery system that maintains continuous airway pressure of 15 cm of water during transportation of the donated lung(s) to the recipient. The Paragonix LUNGguard monitors temperature during transportation of donor lung(s), while the new BAROguard monitors both temperature and pressure during transportation of donor lung(s). In this publication, we present technical aspects of advanced preservation of paediatric donor lungs using the Paragonix BAROguard Donor Lung Preservation System.

Safety of hyperbaric medicine in clinical scenarios.

Hyperbaric therapy is generally considered a safe therapy for the treatment of wounds, mucormycosis, and orthopedic injuries. It is fraught with complications such as barotrauma, pulmonary toxicity, fire hazards, and claustrophobia. This article discusses the safety protocols and preventive aspects on usefulness of this new emerging therapy.

Résumé La thérapie hyperbare est généralement considérée comme une thérapie sûre pour le traitement des plaies, de la mucormycose et des blessures orthopédiques. Elle entraîne de nombreuses complications telles que le barotraumatisme, la toxicité pulmonaire, les risques d'incendie et la claustrophobie. Cet article traite des protocoles de sécurité et des aspects préventifs sur l'utilité de cette nouvelle thérapie émergente. Mots-clés: Claustrophobie, médecine hyperbare, sécurité.

Treatment of pediatric cerebral radiation necrosis using hyperbaric oxygenation.

Introduction: Cerebral radiation necrosis is rarely encountered in pediatric patients. This case report describes a child with cerebral radiation necrosis who was successfully treated using corticosteroids, bevacizumab, and hyperbaric oxygenation. Case report: A 3-year-old boy developed progressive extremity weakness six months after the completion of radiation therapy for the treatment of a neuroepithelial malignancy. Treatment with corticosteroids and bevacizumab was initiated, but his symptoms did not improve, and he was then referred for hyperbaric oxygen therapy. After completing 60 hyperbaric treatments, he experienced significant improvements in mobility, which remained stable over the next year. Discussion: Cerebral radiation necrosis typically presents in children with symptoms of ataxia or headache. Corticosteroids and bevacizumab are common treatments, but hyperbaric oxygen therapy has also been studied as a therapeutic modality for this condition. When considering the use of hyperbaric oxygenation in pediatric patients, careful attention to treatment planning and patient safety can reduce the risks of adverse events such as middle ear barotrauma and confinement anxiety. Conclusion: In addition to other available pharmacologic therapies, hyperbaric oxygenation should be considered for the treatment of pediatric patients with cerebral radiation necrosis.

Orofacial problems in scuba diving: prevalence and prevention-a large-scale survey among civilian divers in France.

Self-contained underwater breathing apparatus (SCUBA) diving is becoming widely democratized among hobbyist practitioners. It can cause orofacial problems, mostly linked to pressure changes. The aim of this study was to assess the prevalence of these problems and to analyze civilian divers' behavior about their dental prevention in France, via a cross-sectional study. Data from 1015 French civilian divers were collected via a nationwide online questionnaire in which participants indicated information concerning orofacial experienced problems during their diving activity, and their medical preventive habits. As results, oral manifestations were experienced by 25.2% of the divers, including barodontalgia (10.8%), mouth syndrome (13.4%), gum pain (2.8%) and dental fractures caused by barotrauma (3.7%) or shocks (1.9%). Mouth syndrome was more frequent among women (18.6%) and divers aged between 18 and 34 years (18.9%). The prevalence of dental fractures increased significantly with age. High diving level was associated with more frequent barodontalgia (17.5%), gum pain (7%) and barotrauma (7.6%). Among respondents, 43.5% completed a dental examination before a diving season and showed fewer oral problems during their scuba diving practice than those who did not. In conclusion, oral problems in scuba diving represent frequent events that can compromise the safety of divers. Despite awareness rising, there is a lack of recourse to the dentist. This leads to incomplete information, especially concerning the preventive means available to divers.

Barotrauma y barodontalgia en la aviación / Barotrauma and barodontalgia in Aviation / Barotrauma e barodontalgia na aviação

Introducción: se ha estudiado ampliamente la importancia de los cambios de presión y sus consecuencias en el cuerpo humano. De esto se desprenden dos conceptos importantes: el barotrauma que se define como el daño producido por cambios en la presión atmosférica; y la barodontalgia que se define como el dolor dentario producido por variaciones de presión barométrica, por ejemplo cuando existen gases atrapados en restauraciones o en la cámara pulpar y/o conducto radicular. Estos conceptos se fundamentan en las leyes de los gases: la Ley de Difusión Gaseosa, la Ley de Dalton, la Ley de Boyle, la Ley de Charles y la Ley de Henry. Discusión: el estudio y prevención de la barodontalgia es de suma importancia, ya que aunque no tiene alta prevalencia entre los aviadores, su aparición es súbita y de alta intensidad, lo que puede provocar en el piloto una incapacidad física y mental, que aumenta el riesgo de accidentes. Conclusiones: en esta revisión, se reúnen las estrategias recomendadas para prevenir su aparición.

Introduction: the importance of pressure changes and their consequences on the human body has been widely studied. Two important concepts arise from this: barotrauma, which is defined as the damage produced by changes in atmospheric pressure; and barodontalgia, which is defined as dental pain produced by variations in barometric pressure, for example when gases are trapped in restorations or in the pulp chamber and/or root canal. These concepts are based on the gas laws: the Law of Gaseous Diffusion, Dalton's Law, Boyle's Law, Charles' Law and Henry's Law. Discusion: the study and prevention of barodontalgia is of utmost importance, since although it is not highly prevalent among aviators, its onset is sudden and of high intensity, which can cause physical and mental incapacity in the pilot, increasing the risk of accidents. Conclusions: this review brings together the recommended strategies to prevent its occurrence.

Introducão: a importância das mudanças de pressão e suas conseqüências sobre o corpo humano têm sido amplamente estudadas. Dois conceitos importantes podem ser derivados disto: barotrauma, que é definido como o dano produzido por mudanças na pressão atmosférica; e barodontalgia, que é definida como a dor dental produzida por variações na pressão barométrica, por exemplo, quando os gases estão presos em restaurações ou na câmara de polpa e/ou canal radicular. Estes conceitos são baseados nas leis do gás: a Lei de Difusão Gasosa, a Lei de Dalton, a Lei de Boyle, a Lei de Charles e a Lei de Henry. Discusion: o estudo e prevenção da barodontia é de suma importância, pois embora não seja muito prevalente entre os aviadores, seu início é repentino e de alta intensidade, o que pode causar incapacidade física e mental no piloto, aumentando o risco de acidentes. Conclusões: esta revisão reúne as estratégias recomendadas para evitar sua ocorrência.

The effect of total compression time and rate (slope) of compression on the incidence of symptomatic Eustachian tube dysfunction and middle ear barotrauma: a Phase II prospective study.

Eustachian tube dysfunction (ETD) and middle ear barotrauma (MEB) are common reported complications during hyperbaric oxygen treatment. Our Phase I study data was the first to demonstrate a statistically significant decrease in the occurrence of symptomatic ETD and MEB. The Phase I Trial suggested the total time interval and rate (slope) of compression (ROC) may be a determining factor in ETD and MEB. This Phase II study investigates an optimal rate of compression to reduce ETD and MEB when considering each multiplace treatment (with multiple patients) as the unit of observation as a group, rather than for each individual patient. Data were collected prospectively on 1,244 group patient-treatment exposures, collectively including 5,072 individual patient-treatment/exposures. We randomly assigned patient-treatment group exposures to four different time interval and rate (slope) of compression. These compression rates and slopes were identical to those used in the Phase I trial. All patients experiencing symptoms of MEB requiring compression stops were evaluated post treatment for the presence of ETD and MEB using the O'Neill Grading System (OGS) for ETD. Data were analyzed using the IBM-SPSS statistical software program. A statistically significant decrease in the number of compression holds was observed in the 15-minute compression schedule, correlating to the results observed in the Phase I trial. The 15-minute linear compression profile continues to demonstrate the decreased need for patient symptomatic compression stops (as in the Phase I trial) using a USN TT9 during elective hyperbaric oxygen treatments in a Class A multiplace hyperbaric chamber. Trial Registration: ClinicalTrials.gov Identifier: NCT04776967.

Prevention of middle ear barotrauma with oxymetazoline/fluticasone treatment.

Middle ear barotrauma (MEB) is a common complication of hyperbaric oxygen (HBO2) therapy. It has been reported in more than 40% of HBO2 treatments and can interrupt the sequence of HBO2. MEB may lead to pain, tympanic membrane rupture, and even hearing loss. The aim of this study was to determine if pretreatment with intranasal fluticasone and oxymetazoline affected the incidence of MEB. We conducted a retrospective chart review of subjects undergoing HBO2 at our institution between February 1, 2014, and May 31, 2019. Subjects in the fluticasone/oxymetazoline (FOT) treatment group used intranasal fluticasone 50 mcg two times per day and oxymetazoline 0.05% one spray two times per day beginning 48 hours prior to initial HBO2. Oxymetazoline was discontinued after four days. Fluticasone was continued for the duration of HBO2 therapy. A total of 154 unique subjects underwent 5,683 HBO2 treatments: 39 unique subjects in the FOT group underwent 1,501 HBO2; 115 unique subjects in the nFOT (no oxymetazoline or fluticasone treatment) group underwent 4,182 HBO2 treatments. The incidence of MEB was 15.4% in the FOT group and 16.2% in the nFOT group. This was not a statistically significant difference (OR = 0.77; p = 0.636). Treatment pressure, age over 65 years, male sex, and BMI were not associated with a difference in MEB incidence. In summary, pretreatment with intranasal oxymetazoline and fluticasone in patients undergoing HBO2 did not significantly reduce MEB. More investigation with larger numbers of participants and prospective studies could further clarify this issue.

Reducing Aortic Barotrauma and Vascular Extracellular Matrix Degradation by Pacemaker-Mediated QRS Widening.

Background The extent of pressure-related damage might be related to acceleration rate of the applied pressure (peak dP/dt) in the vascular system. In this study, we sought to determine whether dP/dt applied to the aortic wall (aortic dP/dt) and in turn vascular extracellular matrix degradation can be mitigated via modulation of left ventricular (LV) contractility (LV dP/dt) by pacemaker-mediated desynchronization. Methods and Results First, in 34 patients, changes in aortic dP/dt values in 3 aortic segments in response to pacemaker-mediated stepwise QRS widening leading to gradual desynchronization of the LV contraction by means of steadily changed atrioventricular delay (AVD) with temporary dual-chamber pacing was examined before and after beta-blocker (15 mg IV metoprolol) administration. Second, serum matrix metalloproteinase-9 levels were measured in the 20 patients with permanent pacemaker while they were on sinus rhythm with normal QRS width and 3 weeks after wide QRS rhythm ensured by dual pacing, dual sensing, and dual response to sensing with short AVD. LV dP/dt substantially correlated with dP/dt measured in ascending (r=0.83), descending (r=0.89), and abdominal aorta (r=0.96). QRS width strongly correlated with dP/dt measured in ascending (r=-0.95), descending (r=-0.92), and abdominal (r=-0.96) aortic segments as well. In patients with permanent pacemaker, wide QRS rhythm led to a significant reduction in serum matrix metalloproteinase-9 levels (from 142.5±32.9 pg/mL to 87.5±32.4 pg/mL [P<0.001]) at the end of 3 weeks follow-up. Conclusions QRS prolongation by short AVD dual pacing, dual sensing, and dual response to sensing results in concomitant decreases in peak dP/dt values in the LV and in all aortic segments with or without background beta-blocker administration, which in turn led to a significant reduction in circulating matrix metalloproteinase-9 levels. Registration URL: https://www.clini​caltr​ials.gov; Unique identifier: NCT03665558.

Validation of neuromuscular blocking agent use in acute respiratory distress syndrome: a meta-analysis of randomized trials.

BACKGROUND: We aimed to synthesize up-to-date trials to validate the effects of neuromuscular blocking agent (NMBA) use in patients with moderate-to-severe acute respiratory distress syndrome (ARDS). METHODS: Several databases including PubMed, EMBASE, Web of Science, and Cochrane Central Register were searched up to November 14, 2019. All randomized trials investigating the use of NMBAs in patients with moderate-to-severe ARDS and reporting mortality data were included in the meta-analysis. The primary outcome was mortality, and the secondary outcomes were clinical outcomes, including respiratory physiological parameters, incidence of barotrauma, ICU-free days, and ventilation-free days. RESULTS: A total of 7 trials enrolling 1598 patients were finally included in this meta-analysis. The results revealed that the use of NMBAs in moderate-to-severe ARDS could significantly decrease the mortality truncated to day 28 (RR 0.74, 95% CI 0.56 to 0.98, P = 0.03) and day 90 (RR 0.77, 95% CI 0.60 to 0.99, P = 0.04). NMBA use could significantly decrease the incidence of barotrauma (RR 0.56, 95% CI 0.36 to 0.87, P = 0.009). No significant difference was observed in ICU-free days or ventilation-free days between the NMBA and control groups. CONCLUSION: The use of NMBAs could significantly decrease mortality in moderate-to-severe ARDS patients and decrease the incidence of barotrauma during mechanical ventilation. However, more large-scale randomized trials are needed to further validate the effect of NMBA use in ARDS.

Proposal of a new scoring system for equalization problems during freediving.

OBJECTIVE: Scuba diving and freediving are popular activities around the world, and their growth has increased the frequency of related pathology. A good ability to equalize is of paramount importance for diving. This is especially true for freediving, during which dive time is limited to just one breath. Even though equalization disorders are quite common in divers, a scoring system does not exist to date. In this paper we propose a new scoring system for equalization problems of freedivers: the EP score, shorthand for "equalization problems." METHODS: We administered the EP score assessment to 40 Italian freediving spearfishermen who were divided in two groups: Group A comprised 20 freedivers complaining of equalization problems and multiple barotraumas but totally asymptomatic in their everyday lives. These individuals had already received medical treatment and nasal surgery without improvement and then had undergone Eustachian tube balloon dilation. Group B comprised 20 healthy freedivers without any history of equalization disorders. We performed a statistical analysis to evaluate the reliability of this scoring system and to evaluate its usefulness in diagnosis and follow-up. RESULTS: Our data show substantial statistical differences between healthy freedivers and freedivers complaining of equalization disorders (Z-Score = -5.396 at p ⟨ 0.05); data do not show any statistical difference between healthy freedivers and patients successfully treated by Eustachian tube balloon dilation (U-value = 152.5 and Z-Score= -1.271 at p ⟨ 0.05). CONCLUSION: The EP score assessment seems to be a reliable tool to quantify equalization disorders during freediving and to evaluate how the difficulty varies over time and after treatment. Since equalization disorders could be present in different populations, the EP score assessment could be applicable to a wider group.

Proof of concept study using a modified Politzer inflation device as a rescue modality for treating Eustachian tube dysfunction during hyperbaric oxygen treatment in a multiplace (Class A) chamber.

Introduction: Eustachian tube dysfunction (ETD) and middle ear barotrauma (MEB) are the most common adverse effects of hyperbaric oxygen (HBO2) treatments. Patients practice equalization maneuvers to prevent ETD and MEB prior to hyperbaric exposure. Some patients are still unable to equalize middle ear pressure. This ETD results in undesirable consequences, including barotrauma, treatment with medications or surgical myringotomy with tube placement and interruption of HBO2. When additional medications and myringotomy are employed, they are associated with additional complications. Methods: A device known as the Ear Popper® has been reported to reduce complications from serous otitis media and reduce the need for surgical interventions (myringotomy). Patients unable to equalize middle ear pressure during initial compression in the hyperbaric chamber were allowed to use the device for rescue. All hyperbaric treatments were compressed using a United States Navy TT9, or a 45-fsw hyperbaric treatment schedule. Patients with persistent ETD and the inability to equalize middle ear pressure were given the Ear Popper upon consideration of terminating their treatment. Results: The Ear Popper allowed all patients to successfully equalize middle ear pressure and complete their treatments. Conclusion: This study substantiates the use of this device to assist in allowing pressurization of the middle ear space in patients otherwise unable to achieve equalization of middle ear pressure during HBO2 treatment in a multiplace chamber.

The effect of compression rate and slope on the incidence of symptomatic Eustachian tube dysfunction leading to middle ear barotrauma: a Phase I prospective study.

Introduction: Symptomatic Eustachian tube dysfunction (ETD) and middle ear barotrauma (MEB) are the most common reported complications during hyperbaric oxygen (HBO2) treatment. There is no standardized rate of compression (ROC) reported to decrease the incidence rates of ETD and MEB during hyperbaric treatments. Few studies actually demonstrate that the ROC decreases the incidence of ETD or MEB. Methods: Our study was designed to determine an optimal hyperbaric chamber compression rate that might reduce the incidence of symptomatic ETD leading to MEB during the compression phase of treatment in a multiplace hyperbaric chamber. Data was collected prospectively over 2,807 elective patient treatments compressed using a U.S. Navy Treatment Table 9 (USN TT9) with a modified ROC. ROC was assigned using two variables, time (10 vs.15 minutes) and slope (linear vs. non-linear compression). Patients were exposed to all four compression schedules in a consecutive daily fashion. We recorded any patient requiring a stop during initial compression due to ear discomfort. Anyone requiring a stop was evaluated post treatment for MEB. Findings were compared to our standard 10-minute linear ROC. Evaluation of the tympanic membrane was accomplished using video otoscopy. Barotrauma when present was classified using both the Teed and O'Neill grading systems. Data was analyzed using basic statistical methods. Results: When comparing four different rates of compression during an elective USN TT9 in a multiplace (Class A) chamber there is a decreased incidence for symptomatic ETD when using a 15-minute linear compression schedule (p-value ⟨0.05). Conclusion: Using a 15-minute linear compression schedule is associated with less symptomatic ETD and less MEB when performing an elective 45 fsw (USN TT9) hyperbaric treatment in a Class A chamber. Asymptomatic ETD and MEB were not considered in this study.

Methods for preventing middle ear barotrauma in computer-controlled pressurization of monoplace hyperbaric chambers.

Middle ear barotrauma (MEB), one of the side effects of hyperbaric oxygen (HBO2) therapy, sometimes cannot be directly diagnosed during the therapy itself. Instead, its incidence and degree are judged based on subjective statements made by patients when in conversation with medical staff regarding how they feel. To prevent MEB in practice, it is proposed that the tympanic membrane evaluation system and automatic control chamber developed in a previous study be applied as part of a prevention algorithm [16]. The proposed algorithm, which determines and equalizes the unbalanced pressure of a subject based on their tympanic admittance, was evaluated in conjunction with conventional HBO2 therapy in an experiment involving 100 subjects. Among the 50 subjects in the control group who received HBO2 therapy 16 subjects experienced MEB. In contrast, the experimental group of 50 subjects were treated with a hyperbaric chamber protocol incorporating the automatic control system and proposed algorithm. At the conclusion of the treatment, no subjects exhibited middle ear barotrauma. In the case of the control group, while the target pressure was achieved, middle ear barotrauma still occurred. However, in the case of the experimental group, the pressure inside the chamber was adjusted as per the algorithm, which allowed the target pressure for every subject to be achieved without experiencing MEB. When a particular subject was unable to perform any pressure equalization method such as swallowing or the Valsalva maneuver, the chamber was not pressurized based on the tympanic admittance and thus no MEB occurred.

Recurrent and Progressive Facial Baroparesis on Flying Relieved by Eustachian Tube Dilation.

OBJECTIVES: Facial baroparesis is a rare phenomenon of seventh cranial nerve palsy traditionally reported in divers, with only 11 cases reported in aviation so far. It is important to correctly diagnose facial baroparesis given the differential diagnosis of stroke and decompression disease and offer appropriate treatment for recurrent cases. METHODS: The authors present the case of a patient with recurrent and progressive facial baroparesis treated with Eustachian tube balloon dilation. Institutional medical records were reviewed, and analysis of the current literature was performed. RESULTS: A 37-year-old woman experienced recurrent and progressive left facial paralysis on descent from altitude on commercial airline flights, with resolution between flights. The patient flew frequently for work-related trips and for the past 7 years had noted facial paralysis that began with mild asymmetry of the face and progressed to an inability to close her left eye. She denied any otologic symptoms other than ear fullness and pressure causing left otalgia. The right side was not involved. After treatment with Eustachian tube dilation, the patient has been on numerous flights with complete resolution of symptoms. CONCLUSIONS: This study presents a rare case of facial baroparesis on commercial flight descent that resolved after left Eustachian tube dilation. Although unilateral facial palsy can be concerning for stroke, a history of ear fullness and pressure may suggest facial baroparesis instead. For recurrent and progressive cases, Eustachian tube dilation should be considered for treatment.

The ineffectiveness of applying moisture to the ear on the incidence and severity of otic barotrauma for air passengers.

OBJECTIVE: The application of moisture to the ear is anecdotally claimed to relieve the pain from otic barotrauma that can arise during aircraft descent. This claim was tested in a randomised double-blind study on an aircraft with eight participants heavily predisposed to barotrauma. METHODS: On the outward flight, half the participants wore 'active' devices that applied moisture to the external ear; the remainder wore placebo devices that contained no moisture, but were otherwise identical. On the return flight, the groups were reversed. Participants wore the devices from just before descent until landing, unless they experienced symptoms of barotrauma, in which case they switched to what they knew was an active device. RESULTS: There were no significant differences between conditions regarding the appearance of the tympanic membrane on landing or the discomfort levels immediately before and after any switch. CONCLUSION: Applying moisture is ineffective for passengers heavily predisposed to otic barotrauma.

Identification and control of a multiplace hyperbaric chamber.

This work presents the automation of a multiplace hyperbaric chamber. It includes the system modeling, identification, controller calculation and system validation. With the proposed approach a good pressure profile tracking and repeatability are achieved. Moreover, the proposed automation includes the implementation of powerful treatment tools such as Pause and Alleviation procedures. The control system implemented is based on a special zero-pole cancellation regulator. Experimental results are provided to illustrate the behavior of the automated chamber. It is important to remark that the chamber automated in this work is being successfully used in a real hospital since 2015 treating more than 40 patients per day, five days a week.

Prevention of Otic Barotrauma in Aviation: A Systematic Review.

OBJECTIVE: To conduct a systematic review of the published evidence relating to the prevention of otic barotrauma in aviation. In particular, this review sought to identify procedures, techniques, devices, and medications for the prevention of otic barotrauma as well as evaluate the evidence relating to their efficacy. DATA SOURCES: Ten databases including Embase, MEDLINE, the Cochrane Database of Systematic Reviews, and the Cochrane Central Register of Controlled Trials were searched using the full historical range. STUDY SELECTION: English language articles including more than or equal to five participants or cases were included. Outcomes of interest were reduced severity or the successful prevention of otic barotrauma in participants undergoing gradual changes in pressure during air travel or its simulation. DATA EXTRACTION: Articles and data were extracted and analyzed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses and other international guidelines. CONCLUSIONS: This review highlights the lack of published evidence relating to what is a significant and increasingly common problem in otology. There is level 1 evidence that supports the efficacy of oral pseudoephedrine (120 mg) in preventing otic barotrauma in adults. However, oral pseudoephedrine (1 mg/kg) does not appear to be effective in children. There is insufficient evidence to support the efficacy of either nasal balloon inflation or pressure-equalizing ear plugs for the prevention of otic barotrauma. A recently reported, novel technique for insertion of temporary tympanostomy tubes is promising but requires further evaluation.

An anti-barotrauma system for preventing barotrauma during hyperbaric oxygen therapy.

In the present study, a tympanometry-based anti-barotrauma (ABT) device was designed using eardrum admittance measurements to develop an objective method of preventing barotrauma that occurs during hyperbaric oxygen (HBO2) therapy. The middle ear space requires active equalization, and barotrauma of these tissues during HBO2therapy constitutes the most common treatment-associated injury. Decongestant nasal sprays and nasal steroids are used, but their efficacy is questionable to prevent middle ear barotrauma (MEB) during HBO2 treatment. Accordingly, a tympanometry-based ABT device was designed using eardrum admittance measurements to develop an objective method for preventing MEB, which causes pain and injury, and represents one of the principal reasons for patients to stop treatment. This study was conducted to test a novel technology that can be used to measure transmembrane pressures, and provide chamber attendants with real-time feedback regarding the patient's equalization status prior to the onset of pain or injury. Eardrum admittance values were measured according to pressure changes inside a hyperbaric oxygen chamber while the system was fitted to the subject. When the pressure increased to above 200 daPa, eardrum admittance decreased to 16.255% of prepressurization levels. After pressure equalization was achieved, eardrum admittance recovered to 95.595% of prepressurization levels. A one-way repeated measures analysis of variance contrast test was performed on eardrum admittance before pressurization versus during pressurization, and before pressurization versus after pressure equalization. The analysis revealed significant differences at all points during pressurization (P⟨0.001), but no significant difference after pressure equalization was achieved. This ABT device can provide objective feedback reflecting eardrum condition to the patient and the chamber operator during HBO2 therapy.