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.

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.

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.

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.

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.

Identifying eustachian tube dysfunction prior to hyperbaric oxygen therapy: Who is at risk for intolerance?

PURPOSE: Determine whether specific risk factors, symptoms and clinical examination findings are associated with hyperbaric oxygen therapy (HBOT) intolerance and subsequent tympanotomy tube placement. MATERIALS AND METHODS: A retrospective case series with chart review was conducted from 2007 to 2016 of patients undergoing HBOT clearance at a tertiary care university hospital in an urban city. Eighty-one (n=81) patient charts were reviewed for risk factors, symptoms and clinical examination findings related to HBOT eustachian tube dysfunction and middle ear barotrauma. Relative risk was calculated for each variable to determine risk for HBOT intolerance and need for tympanotomy tube placement. Risk factor, symptom, physical examination and HBOT complication-susceptibility scores were calculated for each patient. RESULTS: Mean risk factor, clinical and HBOT complication-susceptibility scores were significantly higher in patients who did not tolerate HBOT compared to patients who tolerated HBOT. Patients reporting a history of otitis media, tinnitus, and prior ear surgery were at a higher risk for HBOT intolerance. Patients reporting a history of pressure intolerance and prior ear surgery were more likely to undergo tympanotomy tube placement. Patients noted to have otologic findings prior to HBOT were at a higher risk for both HBOT intolerance and tympanotomy tube placement. CONCLUSIONS: A thorough otolaryngological evaluation can potentially predict and identify patients at risk for HBOT intolerance and tympanotomy tube placement.

Dried salted plum consumption ameliorates hyperbaric oxygen therapy-induced otalgia severity at the first chamber session: a prospective randomized controlled study.

PURPOSE: One of the most common complications of hyperbaric oxygen (HBO2) therapy is middle ear barotrauma (MEB), occasionally causing otalgia. The objective of this study was to evaluate the effect of dried salted plum consumption on MEB and otalgia associated with HBO2 therapy. MATERIALS AND METHODS: Patients undergoing the first chamber session of HBO2 therapy were included in the present prospective randomized controlled trial. The Valsalva maneuver was administered to all patients before HBO2. The patients were randomly divided into two groups: one that ate a dried salted plum during HBO2 treatment and the other that did not. An otoscopic examination was performed after HBO2 therapy. The MEB was graded according to Teed scores. The degree of otalgia was recorded using the Visual Analog Scale (VAS). RESULTS: Ninety patients were enrolled. The overall incidence of MEB (Teed score grade 1~4) was 39.6% (21 of 53) for patients administered a dried salted plum versus 37.8% (14 of 37) for the control group (P=1.000). The incidence of mild MEB (Teed score grade 1~2) and severe MEB (Teed score Grade 3~4) between the two groups was not significantly different. Otalgia was present in 5.7% (3 of 53) of patients administered a dried salted plum versus 18.9% (7 of 37) for the control group (P=.085). No patients administered a dried salted plum had a VAS score ≥4 for otalgia versus 10.8% (4 of 37) for the control group (P=.026). CONCLUSIONS: Dried salted plum consumption does not decrease the incidence of MEB, but may ameliorate the severity of first chamber session HBO2-induced otalgia.

Pressure induced lung injury in a novel in vitro model of the alveolar interface: protective effect of dexamethasone.

PURPOSE: The lungs of infants born with congenital diaphragmatic hernia suffer from immaturity as well as the short and long term consequences of ventilator-induced lung injury, including chronic lung disease. Antenatal and postnatal steroids are among current strategies promoted to treat premature lungs and limit long term morbidity. Although studied in whole-animal models, insight into ventilator-induced injury at the alveolar-capillary interface as well as the benefits of steroids, remains limited. The present study utilizes a multi-fluidic in vitro model of the alveolar-interface to analyze membrane disruption from compressive aerodynamic forces in dexamethasone-treated cultures. METHODS: Human alveolar epithelial cell lines, H441 and A549, were cultured in a custom-built chamber under constant aerodynamic shear followed by introduction of pressure stimuli with and without dexamethasone (0.1µM). On-chip bioelectrical measurements were noted to track changes to the cellular surface and live-dead assay to ascertain cellular viability. RESULTS: Pressure-exposed alveolar cultures demonstrated a significant drop in TEER that was less prominent with an underlying extracellular-matrix coating. Addition of dexamethasone resulted in increased alveolar layer integrity demonstrated by higher TEER values. Furthermore, dexamethasone-treated cells exhibited faster recovery, and the effects of pressure appeared to be mitigated in both cell types. CONCLUSION: Using a novel in vitro model of the alveolus, we demonstrate a dose-response relationship between pressure application and loss of alveolar layer integrity. This effect appears to be alleviated by dexamethasone and matrix sub-coating.

A novel technique of otic barotrauma management using modified intravenous cannulae.

This article provides the first detailed description and systematic evaluation of the management of otic barotrauma using modified intravenous cannulae. A 24-gauge IC cannula was modified as a tool for tympanostomy tube placement and middle ear ventilation. The medical records of 271 ears of 156 adult patients (median age 49 years) who underwent this procedure were reviewed retrospectively. Hundred and ninty-one tubes were placed for otalgia because of hyperbaric oxygen therapy, 58 tubes were inserted for air travel prophylaxis and 22 tubes were placed for management of otic barotrauma post-flight. All the patients who had this procedure for prophylaxis experienced regular otic barotrauma symptoms during air travel prior to tube placement. All patients were reviewed 6 weeks (range 2-9 weeks) post-procedure. This technique of otic barotrauma management worked effectively in 99 % of treated patients. On follow-up, 88 % of tubes were found to be extruded and non-extruded tubes were removed in clinic without any anaesthesia. 99.6 % of tympanic membrane had healed completely and spontaneously without sequelae. Given the safety, effectiveness, low risk of complications associated with this novel tympanostomy technique, it provided a simple yet effective therapeutic option for the management of otic barotrauma. Finally, this technique can be easily applied in all health settings as it only requires medical supplies readily available in hospitals, therefore there is no additional cost.

Medidas generales de prevención de accidentes hipobáricos-hiperbáricos en la esfera otorrinolaringológica / General measures for preventing hypo-hyperbaric accidents in otorhinolaryngology

Los accidentes barotraumáticos en la esfera otorrinolaringológica son muy frecuentes, especialmente el de oído medio. Prevenirlos es una de las tareas en las que más hincapié debemos hacer. Para ello, debemos realizar un estudio anatómico de vías altas en el que analicemos las fosas nasales y el cavum, así como estudios de función tubárica y estudios radiológicos para cuantificar la neumatización mastoidea. Es importante conocer las maniobras de compensación tubárica más comunes, así como la fisiopatología del propio barotrauma. En las personas con el diagnóstico de enfermedades que comprometen la función tubárica o el normal drenaje de los ostia sinusales, podemos aplicar medidas y tratamientos específicos que solucionan los problemas de compensación de presiones. En el medio aéreo se dispone de unas medidas muy sencillas encaminadas a la prevención de los barotraumas de oído (AU)

Barotrauma accidents are highly frequent in otorhinolaryngology, especially those involving the middle ear. Emphasis should be placed on preventing these lesions. To do this, anatomical study of the upper airways should be performed with analysis of the nasal fossae and cavum, as well as evaluation of Eustachian tube function and radiological tests to quantify mastoid pneumatization. Otorhinolaryngologists should be familiar with the most common maneuvers of tubal compensation, as well as the physiopathology of barotrauma. In patients diagnosed with disorders that can compromise Eustachian tube function or normal drainage of the sinus ostium, specific measures and treatments can be applied that solve the problems of pressure compensation. In flying, several simple measures are available to prevent barotrauma to the ear (AU)

[The prevention of the ear barotrauma by positive pressure on nasopharynx].

OBJECTIVE: To explore if the ear barotrauma could be prevented or not if the provided nasopharyngeal pressure is higher than the Eustachian tube resistance during the pressure increases in the hyperbaric chamber. METHOD: Eight volunteers of healthy men were divided into 4 groups, with 2 persons in each group who were the tested and the control for each other. The positive pressure of 6kPa was given via mask to the nasopharynx of the tested, while the control took normal breath. The pressure in the hyperbaric chamber was increased by 5kPa with the velocity of 0.5kPa/s. No positive or negative measurement to open Eustachian tube was allowed for both tested and controls. The pressure within the tympanic cavity was measured. Similarly, the pressure in the hyperbaric chamber was increased by 20kPa with the same velocity. The tested were not allowed to adjust the Eustachian tube, while the controls could do so. The pressure within the tympanic cavity was measured once again. RESULT: When 5 kPa in the hyperbaric chamber was reached, the pressure within the tympanic cavity of the tested and the control was -11.2 daPa and -168.6 daPa (P < 0.01), respectively. When 20 kPa was reached, the pressure within the tympanic cavity of the tested and the control was -8.3 daPa and -7.6 daPa (P > 0.05), respectively. Ear barotrauma could be prevented by providing positive pressure which is higher than the Eustachian tube resistance through mask to the nasopharynx.

Does the slow compression technique of hyperbaric oxygen therapy decrease the incidence of middle-ear barotrauma?

OBJECTIVE: To note the incidence of middle-ear barotrauma following standard and slow compression during hyperbaric oxygen therapy (HBOT). The standards used were: (1) less than 40 per cent of the cohort should develop barotraumas, and (2) the incidence of barotrauma following the slow technique should be less than that caused by the standard technique. DESIGN: Prospective clinical audit. MATERIAL AND METHODS: Forty-two consecutive patients who received either standard compression or slow compression HBOT were included. Pre- and post-treatment otoscopy (graded according to a modified Teed's scale), tympanometry, audiometry and subjective ear complaints were compared between the groups and also compared with the set standard. RESULTS: Significantly less middle-ear barotrauma was noted when using the slow compression technique compared with the standard compression technique (p < 0.05). The incidence of barotrauma when using standard compression failed to meet the set standard of less than 40 per cent. CONCLUSION: The slow compression method of HBOT proved to be both safe and superior to the standard compression technique.

Complications and side effects of hyperbaric oxygen therapy.

BACKGROUND: Despite ongoing controversy, hyperbaric oxygen (HBO) therapy is frequently administered in various clinical situations. Probably because of the unique atmospheric conditions to which the patient is exposed, there are concerns about the safety aspects of this therapy. Possible complications during HBO therapy include barotraumatic lesions (middle ear, nasal sinuses, inner ear, lung, teeth), oxygen toxicity (central nervous system, lung), confinement anxiety, and ocular effects (myopia, cataract growth). METHODS: To analyze the medical safety of HBO therapy, this report reviewed complications and side effects of 782 patients treated for various indications with a total of 11,376 HBO therapy sessions within a multiplace chamber. The absolute treatment pressure was 240 or 250 kPa 114 or 15 msw). The compression was performed in a linear manner with 14 to 15 kPa (1.4 to 1.5 msw) x min(-1). All data were gathered prospectively within a special database. RESULTS: More than 17% of all patients experienced ear pain or discomfort as an expression of problems in equalizing the middle ear pressure. Most episodes were not related to a persistent eustachian tube dysfunction since they only occurred once. Barotraumatic lesions on visual otological examinations (ear microscopy) were verified in 3.8% of all patients. Patients with sensory deficits involving the ear region need special attention, because they seem to be at risk for rupture of the tympanic membrane (three cases documented). A barotrauma of the nasal sinuses occurred rarely and no barotraumatic lesions of the inner ear, lung, or teeth were noted. Oxygen toxicity of the CNS manifested by generalized seizures affected four patients without any recognizable risk factors or prodromes. None of the patients suffered recurrences or sequelae. Regular checks of the blood glucose in diabetics failed to reveal episodes of hypoglycemia as a cause for seizures. Lung function tests of patients undergoing prolonged treatment (average 52.8 sessions) did not deteriorate. CONCLUSION: Patients scheduled for HBO therapy need a careful pre-examination and monitoring. If safety guidelines are strictly followed, HBO therapy is a modality with an acceptable rate of complications. The predominant complication is represented by pressure equalization problems within the middle ear. Serious complications rarely occur.

Complications of tympanostomy tubes inserted for facilitation of hyperbaric oxygen therapy.

OBJECTIVE: To document the incidence of complications occurring secondary to placement of tympanostomy tubes in patients undergoing hyperbaric oxygen therapy. DESIGN: Retrospective chart review. SETTING: Tertiary referral center. PATIENTS: Forty-five patients referred to the Department of Otolaryngology for inability to tolerate hyperbaric oxygen therapy between January 1, 1990, and December 31, 1995. INTERVENTIONS: All patients underwent bilateral myringotomy and tube placement. OUTCOME MEASURES: Charts were reviewed for complications of tube placement, including otorrhea, otalgia, hearing loss, persistent perforations, and tinnitus. RESULTS: Seventeen (38%) of 45 patients experienced complications, with most having more than 1. Most complications occurred after conclusion of hyperbaric oxygen therapy. Otorrhea was most common, occurring in 13 patients (29%). Persistent tympanic membrane perforations occurred in 7 patients (16%). CONCLUSIONS: The rate of complications is higher than reported for placement of tympanostomy tubes in other patient populations. Coexisting illness, such as diabetes mellitus, may contribute to the development of complications in patients undergoing hyperbaric oxygen therapy. Alternative methods of tympanostomy, with emphasis on shorter duration of intubation, should be considered in this patient population.

Inner and middle ear hyperbaric oxygen-induced barotrauma.

Patients receiving hyperbaric oxygen (HBO) therapy can sustain inner and middle ear barotrauma. The purpose of this study is to define the incidence and significance of HBO-related barotrauma, in addition to establishing guidelines for prophylactic myringotomy or tympanostomy tube placement. Thirty patients were stratified into two groups (those able to autoinflate and those unable to autoinflate the middle ear) and barotrauma was assessed by otoscopy, tympanometry, high-frequency audiometry, and distortion product otoacoustic emission (DPOAE) testing. Ten of 11 patients (91%) from the noninflater group suffered middle ear barotrauma, and seven of 19 patients (37%) from the autoinflater group sustained middle ear barotrauma. Patients unable to autoinflate the middle ear were shown to have a higher incidence and greater severity of barotrauma than patients able to autoinflate. Pretreatment pressure-equalizing tubes or myringotomies should be considered for patients undergoing HBO therapy who have an artificial airway or have eustachian tube dysfunction and have failed conservative medical intervention. A significant change in DPOAEs (loss of emissions over a 1-kHz range) was found in four of 15 autoinflaters (27%) and two of seven noninflaters (29%). There was no significant difference between the groups. The decrease in DPOAEs was not associated with a change in conventional audiometry.

Prophylaxis against middle ear barotrauma in US hyperbaric oxygen therapy centers.

The most common complication of hyperbaric oxygen (HBO) treatment is middle ear barotrauma, which can lead to permanent hearing loss and vertigo. Unconscious patients and infants present a special diagnostic challenge because of difficulties in communicating pain and equalizing pressure across the ears. This study involved a phone survey to all hospital-based HBO centers in the United States concerning routine practice for middle ear barotrauma prophylaxis. Results indicate that more than a fifth of centers always do routine prophylactic myringotomies on intubated patients (30 of 126) and infants (19 of 86). Less than half of centers never performed the procedure as routine prophylaxis. A third of centers (49 of 145) routinely administered prophylactic drugs before HBO treatment. Topical nasal decongestants, particularly oxymetazoline, were preferred to systemic oral medications (chi2 = 20.8, P<.001). These results show that there is great variance in clinical practice with regard to middle ear barotrauma prophylaxis among US HB0 centers. Many centers are using unproven therapies such as topical nasal decongestants.