Pneumothorax during manned chamber operations: A summary of reported cases.

In-chamber pneumothorax has complicated medically remote professional diving operations, submarine escape training, management of decompression illness, and hospital-based provision of hyperbaric oxygen therapy. Attempts to avoid thoracotomy by combination of high oxygen partial pressure breathing (the concept of inherent unsaturation) and greatly slowed rates of chamber decompression proved successful on several occasions. When this delicate balance designed to prevent the intrapleural gas volume from expanding faster than it contracts proved futile, chest drains were inserted. The presence of pneumothorax was misdiagnosed or missed altogether with disturbing frequency, resulting in wide-ranging clinical consequences. One patient succumbed before the chamber had been fully decompressed. Another was able to ambulate unaided from the chamber before being diagnosed and managed conventionally. In between these two extremes, patients experienced varying degrees of clinical compromise, from respiratory distress to cardiopulmonary arrest, with successful resuscitation. Pneumothorax associated with manned chamber operations is commonly considered to develop while the patient is under pressure and manifests during ascent. However, published reports suggest that many were pre-existing prior to chamber entry. Risk factors included pulmonary barotrauma-induced cerebral arterial gas embolism, cardiopulmonary resuscitation, and medical or surgical procedures usually involving the lung. This latter category is of heightened importance to hyperbaric operations as an iatrogenically induced pneumothorax may take as long as 24 hours to be detected, perhaps long after a patient has been cleared for chamber exposure.

Hyperbaric oxygen treatment for infants: retrospective analysis of 54 patients treated in two tertiary care centres.

Introduction: We aimed to analyse the outcomes of hyperbaric oxygen treatment (HBOT) and describe difficulties encountered in infants, a rare patient population in this therapeutic intervention, with limited scientific reports. Methods: This was a retrospective analysis of patients 12 months old or younger who underwent HBOT in two different institutions. Demographic data, clinical presentation, HBOT indication, chamber type, oxygen delivery method, total number of treatments, outcome and complications were extracted from clinical records. Results: There were 54 infants in our study. The patients' median age was 3.5 (range 0-12) months. The major HBOT indication was acute carbon monoxide intoxication (n = 32). A total of 275 HBOT treatments were administered, mostly performed in multiplace chambers (n = 196, 71%). Only one patient (2%) required mechanical ventilation. Acute signs were fully resolved in the most patients (n = 40, 74%). No complications related to HBOT were reported. Conclusions: This study suggests that HBOT may be a safe and effective treatment for infants. Paediatricians should consider HBOT when indicated in infants even for the preterm age group.

Secondary deterioration in a patient with cerebral and coronary arterial gas embolism after brief symptom resolution: a case report.

Introduction: Hyperbaric oxygen treatment (HBOT) is recommended for arterial gas embolism (AGE) with severe symptoms. However, once symptoms subside, there may be a dilemma to treat or not. Case presentation: A 71-year-old man was noted to have a mass shadow in his left lung, and a transbronchial biopsy was performed with sedation. Flumazenil was intravenously administered at the end of the procedure. However, the patient remained comatose and developed bradycardia, hypotension, and ST-segment elevation in lead II. Although the ST changes spontaneously resolved, the patient had prolonged disorientation. Whole- body computed tomography revealed several black rounded lucencies in the left ventricle and brain, confirming AGE. The patient received oxygen and remained supine. His neurological symptoms gradually improved but worsened again, necessitating HBOT. HBOT was performed seven times, after which neurological symptoms resolved almost completely. Conclusions: AGE can secondarily deteriorate after symptoms have subsided. We recommend that HBOT be performed promptly once severe symptoms appear, even if they resolve spontaneously.

Use of hyperbaric oxygen therapy in severe earthquake injuries.

BACKGROUND: Earthquakes are natural disasters that can often cause severe injuries and traumatic situations. These injuries can include crush injuries, fractures, tissue damage, and blood circulation problems. Hyperbaric oxygen therapy (HBOT) has recently become a frequently used treatment modality for individuals suffering from severe injuries. HBOT is a form of treatment that involves administering pure oxygen to the patient under high pressure. This treatment aims to promote tissue healing by increasing cellular oxygenation. It is thought to have a positive effect on factors such as accelerating tissue healing, reducing inflammation, and controlling infection in severe post-earthquake injuries, particularly crush injuries. This study aimed to retrospectively evaluate the clinical effects, contributions to the healing process, and potential advantages of HBOT in 35 patients with severe injuries after the Kahramanmaras earthquake that occurred on 06.02.2023 and to contribute to the development of emergency intervention strategies. METHODS: This study was carried out after ethics committee approval. In the study, the data of patients with a MESS Score between 7-14 who were admitted as earthquake victims and treated in the HBOT Unit due to severe earthquake-related injuries were obtained from records and retrospectively analyzed. Demographic information, general distribution of patient data, mean values, number of HBOT sessions, and functional outcomes were recorded. RESULTS: The gender distribution of the 35 patients who received HBOT was 31.4% male and 68.6% female. 45.7% of patients were aged 18 years or younger, and 54.3% were aged 19 years or older. The most common injuries in the treated patients were observed in the lower extremities. After HBOT, sensory recovery (54.3%) and functional recovery (51.4%) were achieved in the majority of patients. The minor amputation rate was 20.0% and the major amputation rate was 11.4% after HBOT. CONCLUSION: This study evaluated the possible effects of HBOT on patients with severe earthquake injuries in Türkiye, and the results showed that HBOT may have a beneficial effect on critical factors such as sensory recovery, functional recovery, and amputation rates in this particular group of patients, and that this benefit may be more pronounced in those who started treatment early.

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.

Safety of hyperbaric oxygen therapy in patients with heart failure: A retrospective cohort study.

BACKGROUND: Hyperbaric oxygen therapy (HBOT) has several hemodynamic effects including increases in afterload (due to vasoconstriction) and decreases in cardiac output. This, along with rare reports of pulmonary edema during emergency treatment, has led providers to consider HBOT relatively contraindicated in patients with reduced left ventricular ejection fraction (LVEF). However, there is limited evidence regarding the safety of elective HBOT in patients with heart failure (HF), and no existing reports of complications among patients with HF and preserved LVEF. We aimed to retrospectively review patients with preexisting diagnoses of HF who underwent elective HBOT, to analyze HBOT-related acute HF complications. METHODS: Research Ethics Board approvals were received to retrospectively review patient charts. Patients with a history of HF with either preserved ejection fraction (HFpEF), mid-range ejection fraction (HFmEF), or reduced ejection fraction (HFrEF) who underwent elective HBOT at two Hyperbaric Centers (Toronto General Hospital, Rouge Valley Hyperbaric Medical Centre) between June 2018 and December 2020 were reviewed. RESULTS: Twenty-three patients with a history of HF underwent HBOT, completing an average of 39 (range 6-62) consecutive sessions at 2.0 atmospheres absolute (ATA) (n = 11) or at 2.4 ATA (n = 12); only two patients received fewer than 10 sessions. Thirteen patients had HFpEF (mean LVEF 55 ± 7%), and seven patients had HFrEF (mean LVEF 35 ± 8%) as well as concomitantly decreased right ventricle function (n = 5), moderate/severe tricuspid regurgitation (n = 3), or pulmonary hypertension (n = 5). The remaining three patients had HFmEF (mean LVEF 44 ± 4%). All but one patient was receiving fluid balance therapy either with loop diuretics or dialysis. Twenty-one patients completed HBOT without complications. We observed symptoms consistent with HBOT-related HF exacerbation in two patients. One patient with HFrEF (LVEF 24%) developed dyspnea attributed to pulmonary edema after the fourth treatment, and later admitted to voluntarily holding his diuretics before the session. He was managed with increased oral diuretics as an outpatient, and ultimately completed a course of 33 HBOT sessions uneventfully. Another patient with HFpEF (LVEF 64%) developed dyspnea and desaturation after six sessions, requiring hospital admission. Acute coronary ischemia and pulmonary embolism were ruled out, and an elevated BNP and normal LVEF on echocardiogram confirmed a diagnosis of pulmonary edema in the context of HFpEF. Symptoms subsided after diuretic treatment and the patient was discharged home in stable condition, but elected not to resume HBOT. CONCLUSIONS: Patients with HF, including HFpEF, may develop HF symptoms during HBOT and warrant ongoing surveillance. However, these patients can receive HBOT safely after optimization of HF therapy and fluid restriction.

Efficacy and safety of hyperbaric oxygen therapy in acute ischaemic stroke: a systematic review and meta-analysis.

OBJECTIVE: This study aims to evaluate the efficacy and safety of adjunctive hyperbaric oxygen therapy (HBOT) in acute ischaemic stroke (AIS) based on existing evidence. METHODS: We conducted a comprehensive search through April 15, 2023, of seven major databases for randomized controlled trials (RCTs) comparing adjunctive hyperbaric HBOT with non-HBOT (no HBOT or sham HBOT) treatments for AIS. Data extraction and assessment were independently performed by two researchers. The quality of included studies was evaluated using the tool provided by the Cochrane Collaboration. Meta-analysis was conducted using Rev Man 5.3. RESULTS: A total of 8 studies involving 493 patients were included. The meta-analysis showed no statistically significant differences between HBOT and the control group in terms of NIHSS score (MD = -1.41, 95%CI = -7.41 to 4.58), Barthel index (MD = 8.85, 95%CI = -5.84 to 23.54), TNF-α (MD = -5.78, 95%CI = -19.93 to 8.36), sICAM (MD = -308.47, 95%CI = -844.13 to 13227.19), sVCAM (MD = -122.84, 95%CI = -728.26 to 482.58), sE-selectin (MD = 0.11, 95%CI = -21.86 to 22.08), CRP (MD = -5.76, 95%CI = -15.02 to 3.51), adverse event incidence within ≤ 6 months of follow-up (OR = 0.98, 95%CI = 0.25 to 3.79). However, HBOT showed significant improvement in modified Rankin score (MD = 0.10, 95%CI = 0.03 to 0.17), and adverse event incidence at the end of treatment (OR = 0.42, 95%CI = 0.19 to 0.94) compared to the control group. CONCLUSION: While our findings do not support the routine use of HBOT for improving clinical outcomes in AIS, further research is needed to explore its potential efficacy within specific therapeutic windows and for different cerebral occlusion scenarios. Therefore, the possibility of HBOT offering clinical benefits for AIS cannot be entirely ruled out.

Hyperbaric oxygen augments susceptibility to C. difficile infection by impairing gut microbiota ability to stimulate the HIF-1α-IL-22 axis in ILC3.

Hyperbaric oxygen (HBO) therapy is a well-established method for improving tissue oxygenation and is typically used for the treatment of various inflammatory conditions, including infectious diseases. However, its effect on the intestinal mucosa, a microenvironment known to be physiologically hypoxic, remains unclear. Here, we demonstrated that daily treatment with hyperbaric oxygen affects gut microbiome composition, worsening antibiotic-induced dysbiosis. Accordingly, HBO-treated mice were more susceptible to Clostridioides difficile infection (CDI), an enteric pathogen highly associated with antibiotic-induced colitis. These observations were closely linked with a decline in the level of microbiota-derived short-chain fatty acids (SCFAs). Butyrate, a SCFA produced primarily by anaerobic microbial species, mitigated HBO-induced susceptibility to CDI and increased epithelial barrier integrity by improving group 3 innate lymphoid cell (ILC3) responses. Mice displaying tissue-specific deletion of HIF-1 in RORγt-positive cells exhibited no protective effect of butyrate during CDI. In contrast, the reinforcement of HIF-1 signaling in RORγt-positive cells through the conditional deletion of VHL mitigated disease outcome, even after HBO therapy. Taken together, we conclude that HBO induces intestinal dysbiosis and impairs the production of SCFAs affecting the HIF-1α-IL-22 axis in ILC3 and worsening the response of mice to subsequent C. difficile infection.

Effectiveness of Repetitive Hyperbaric Oxygen Therapy for Chronic Limb-Threatening Ischemia.

BACKGROUND: Lower extremity artery disease is strongly associated with morbidity and is typically addressed through revascularization interventions. We assessed the clinical outcomes of patients with chronic limb-threatening ischemia (CLTI) without revascularization who did and did not undergo repetitive hyperbaric oxygen therapy (HBOT). METHODS: Between April 2002 and March 2017, the records of 58 patients with CLTI (Rutherford classification 4 in 19% and 5 in 81%) were evaluated retrospectively. HBOT was performed at 2.8 atm of oxygen (HBOT group). The control group included those who could not continue HBOT and historical controls. Patients in poor general health or with an indication for revascularization therapy were excluded. We examined major adverse events (MAEs) and limb salvage rates. Independent predictors and risk stratification were analyzed using a multivariate regression analysis. RESULTS: The mean age was 71±13 years. Of all patients, 67% had diabetes and 43% were undergoing hemodialysis. The mean follow-up period was 4.3±0.8 years. The overall survival rate was 84.5% and 81.0% at 1 and 3 years, respectively. The Cox regression analysis indicated that high body mass index (odds ratio [OR]: 0.86; 95% confidence interval [CI]: 0.76-0.97; p=0.01), well-nourished (OR: 1.21; 95% CI: 1.01-1.45), and HBOT (OR: 0.05; 95% CI: 0.01-0.26; p<0.001) independently predicted absence of MAEs. For major limb amputation, the ankle-brachial index (OR: 0.2; 95% CI: 0.05-0.86; p=0.03) and HBOT (OR: 0.04; 95% CI: 0.004-0.32; p=0.003) were independent predictors. CONCLUSIONS: Repetitive, stand-alone HBOT was associated with MAE-free survival and limb salvage in patients with CLTI.

Efficacy and Safety of Hyperbaric Oxygen Therapy in Fistulizing Crohn's Disease: A Systematic Review and Meta-analysis.

BACKGROUND: Hyperbaric oxygen therapy (HBOT) delivers 100% oxygen in a pressurized chamber, increasing tissue oxygen levels and regulating inflammatory pathways. Mounting evidence suggests that HBOT may be effective for inflammatory bowel disease. Our systematic review and meta-analysis aimed to quantify the efficacy and safety of HBOT in fistulizing Crohn's disease (CD). METHODS: A systematic review was conducted using the EMBASE, Web of Science, Pubmed, and Cochrane Library databases according to the "Preferred Reporting Items for Systematic Reviews and Meta-analyses" criteria. Study bias was assessed using the Cochrane Handbook guidelines. RESULTS: Sixteen studies with 164 patients were included in the analysis. For all fistula subtypes, the pooled overall clinical response was 87% (95% CI: 0.70-0.95, I2 = 0) and the pooled clinical remission was 59% (95% CI: 0.35-0.80, I2 = 0). The overall clinical response was 89%, 84%, and 29% for perianal, enterocutaneous, and rectovaginal fistulas, respectively. On meta-regression, hours in the chamber and the number of HBOT sessions were not found to correlate with clinical response. The pooled number of adverse events was low at 51.7 per 10,000 HBOT sessions for all fistula types (95% CI: 16.8-159.3, I2 = 0). The risk of bias was observed across all studies. CONCLUSION: HBOT is a safe and potentially effective treatment option for fistulizing CD. Randomized control trials are needed to substantiate the benefit of HBOT in fistulizing CD.

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.

Analysis of the cardiovascular effects of hyperbaric oxygen therapy in diabetic patients.

During hyperbaric oxygen (HBO2) therapy in humans, there are changes in cardiovascular physiology due to high pressure and hyperoxygenation. Peripheral vasoconstriction, bradycardia, and a decrease in cardiac output are observed during HBO2 therapy. These physiological effects of HBO2 therapy on the cardiovascular system are tolerated in healthy people. However, patients with underlying cardiac disease may experience severe problems during HBO2 therapy, such as pulmonary edema and death. In addition, cardiac complications may occur in patients with diabetes mellitus (DM). Therefore, HBO2 therapy may negatively affect cardiovascular physiology in patients with DM. The present study aimed to examine the cardiovascular effects of HBO2 therapy in diabetic patients. The findings of NT-ProBNP, troponin I, and electrocardiography (ECG) of diabetic patients who applied to the Ministry of Health University Gülhane Training Research Underwater and Hyperbaric Medicine Clinic were compared before and after the first HBO2 therapy session. When ECG findings were analyzed at the end of a session of HBO2 exposure, a statistically significant increase was observed in the QTc and QTc dispersion measurements (p≺0.001 and p = 0.02, respectively). In cardiac enzymes, there was a statistically significant increase in troponin I values after an HBO2 therapy session, but no statistically significant change was observed in Pro-BNP (p = 0.009, p = 0.3, respectively). Short-term exposure to HBO2 therapy had statistically significant changes in troponin I, QT, and QTc in patients with DM, which did not reach clinical significance. Despite very little evidence of cardiac dysfunction, we recommend caution in using HBO2 therapy in patients with DM and emphasize the need for further investigation of these measurements.

Hyperbaric oxygen therapy for treatment of COVID-19-related parosmia: a case report.

Parosmia is a qualitative olfactory dysfunction characterized by distortion of odor perception. Traditional treatments for parosmia include olfactory training and steroids. Some patients infected with COVID-19 have developed chronic parosmia as a result of their infection. Here, we present the case of a patient who developed parosmia after a COVID-19 infection that was not improved by traditional treatments but found significant improvement after hyperbaric oxygen therapy[A1].

Results of acute cerebral infarction treatment with hyperbaric oxygen therapy, 2020-2022.

BACKGROUND: Cerebral stroke is the third leading cause of death after cardiovascular disease, cancer and the leading cause of disability for patients. Hyperbaric oxygen is a non-drug treatment that has the potential to improve brain function for patients with ischaemic stroke. The objective of this study was to evaluate the results of treatment of acute cerebral infarction with hyperbaric oxygen therapy (HBOT). MATERIALS AND METHODS: This was a case-control study. One hundred ninety-five patients diagnosed with cerebral infarction, with signs of onset within 24 hours, were treated at the Centre for Underwater Medicine and Hyperbaric Oxygen of Vietnam National Institute of Maritime Medicine during the period from January 2020 to December 2022. Study group included 100 patients with acute cerebral infarction treated with a combination of HBOT and medication and reference group included 95 patients treated by medication only (antiplatelets drugs, statins, control of associated risks factors) RESULTS: After 7 days of treatment with hyperbaric oxygen (HBO), symptoms such as headache, dizziness, nausea, sensory disturbances, and Glasgow score of the study group improved better than that of the reference group (p < 0.01). Movement recovery in the study group was better than the reference group: the percentage of patients with mild and moderate paralysis in the study group increased higher than that of the reference group (86.0% and 68.4%), the degree of complete paralysis of the study group decreased more than that of the reference group (14.0% and 31.6%). The degree of independence in daily activities in the study group was better than the reference group. In the study group, the percentage of patients with complete independence in daily life increased from 27.0% to 84.0%. In the reference group, the rate of patients who were independent in their daily activities increased from 37.9% to 51.6%. The average number of treatment days of the study group was 10.32 ± 2.41 days and it the reference group 14.51 ± 3.24 days. CONCLUSIONS: Hyperbaric oxygen therapy is a non-drug treatment with many good effects in the treatment of cerebral infarction, especially acute cerebral infarction. HBOT reduces and improves functional symptoms, improves mobility, and reduces treatment time for patients.

Two Cases of Intractable Radiation-Induced Hemorrhagic Cystitis Treated with Transcatheter Embolization.

Radiation-induced hemorrhagic cystitis is a late complication of radiotherapy, and in rare cases, refractory. Refractory bleeding may not be resolved by transurethral electrocoagulation (TUEC) or hyperbaric oxygen (HBO) therapy and requires transcatheter arterial embolization (TAE) or urinary diversion. Here, we report two cases of radiation-induced hemorrhagic cystitis successfully treated with TAE. Case 1 was a 61-yearold man who underwent total prostatectomy for prostate cancer followed by salvage radiation therapy. The patient developed radiation-induced hemorrhagic cystitis 2 years and 3 months after radiotherapy. After no improvement with TUEC and HBO, TAE was performed. Case 2 was a 78-year-old man who underwent total prostatectomy followed by salvage radiation therapy and developed radiation-induced hemorrhagic cystitis 12 years later. TAE was performed after no improvement with HBO. TAE proved successful in both patients, and there was no relapse. TAE is a potential treatment option for refractory radiation-induced hemorrhagic cystitis.

[Cerebral arterial air embolism: the effect of hyperbaric oxygen therapy]. / Cerebrale arteriële luchtembolie.

BACKGROUND: Iatrogenic gas embolism is the presence of gas in vascular structures. Feared are those in coronary or cerebral arteries. These can result in cerebral or myocardial infarction. CASE DESCRIPTION: A 79-year-old female underwent CT-guided biopsy of the lung. Minutes later she developed neurological symptoms. After administration of oxygen her symptoms initially improved, but later worsened. Based on her symptoms air embolism was suspected. She recovered fully after treatment with hyperbaric oxygen. CONCLUSION: Air embolism is a potentially life-threatening complication of surgical, radiological or vascular interventions. Early recognition can lead to prompt treatment and better prognosis. If air embolism is suspected the patient should be treated according to ABCDE principles and oxygen should be administered. In case of neurological or circulatory symptoms a hospital that could provide hyperbaric oxygen therapy should be contacted as soon as possible.

Haemorrhagic cystitis: a review of management strategies and emerging treatments.

Haemorrhagic cystitis (HC) is characterised by persistent haematuria and lower urinary tract symptoms following radiotherapy or chemotherapy. Its pathogenesis is poorly understood but thought to be related to acrolein toxicity following chemotherapy or fibrosis/vascular remodelling after radiotherapy. There is no standard of care for patients with HC, although existing strategies including fulguration, hyperbaric oxygen therapy, botulinum toxin A, and other intravesical therapies have demonstrated short-term efficacy in cohort studies. Novel agents including liposomal tacrolimus are promising targets for further research. This review summarises the incidence and pathogenesis of HC as well as current evidence supporting its different management strategies.

Early hyperbaric oxygen therapy is associated with favorable outcome in patients with iatrogenic cerebral arterial gas embolism: systematic review and individual patient data meta-analysis of observational studies.

BACKGROUND: Iatrogenic cerebral arterial gas embolism (CAGE) caused by invasive medical procedures may be treated with hyperbaric oxygen therapy (HBOT). Previous studies suggested that initiation of HBOT within 6-8 h is associated with higher probability of favorable outcome, when compared to time-to-HBOT beyond 8 h. We performed a group level and individual patient level meta-analysis of observational studies, to evaluate the relationship between time-to-HBOT and outcome after iatrogenic CAGE. METHODS: We systematically searched for studies reporting on time-to-HBOT and outcome in patients with iatrogenic CAGE. On group level, we meta-analyzed the differences between median time-to-HBOT in patients with favorable versus unfavorable outcome. On individual patient level, we analyzed the relationship between time-to-HBOT and probability of favorable outcome in a generalized linear mixed effects model. RESULTS: Group level meta-analysis (ten studies, 263 patients) shows that patients with favorable outcome were treated with HBOT 2.4 h (95% CI 0.6-9.7) earlier than patients with unfavorable outcome. The generalized linear mixed effects model (eight studies, 126 patients) shows a significant relationship between time-to-HBOT and probability of favorable outcome (p = 0.013) that remains significant after correcting for severity of manifestations (p = 0.041). Probability of favorable outcome decreases from approximately 65% when HBOT is started immediately, to 30% when HBOT is delayed for 15 h. CONCLUSIONS: Increased time-to-HBOT is associated with decreased probability of favorable outcome in iatrogenic CAGE. This suggests that early initiation of HBOT in iatrogenic CAGE is of vital importance.

Paracentral acute middle maculopathy in a fasting patient after cataract surgery and its response to hyperbaric oxygen therapy.

INTRODUCTION: Paracentral acute middle maculopathy (PAMM) is a structural optical coherence tomography (OCT) sign secondary to ischemia in the intermediate and deep retinal vascular network, characterized by hyperreflectivity in the inner nuclear layer (INL). AIM: Our objective is to demonstrate PAMM development following uncomplicated cataract surgery, possibly triggered by fasting and dehydration. We also aim to emphasize the potential role of hyperbaric oxygen therapy in treating PAMM. CASE PRESENTATION: A 66-year-old man with a past medical history of Neurofibromatosis type 1 and cardiovascular disease underwent uncomplicated cataract surgery in the left eye. The patient was also fasting due to Ramadan. The patient complained of very low vision during the routine postoperative examination on the third day. His-best-corrected visual acuity (BCVA) was counting fingers at 1 meter. His-anterior and posterior segment examination was unremarkable. In infrared imaging, a large hyporeflective area was observed in the parafoveal region, and structural OCT also showed increased hyperreflectivity in the middle retinal layers corresponding to the junction of INL and outer plexiform layer (OPL) involving the entire INL which suggested PAMM. Following 14 sessions of hyperbaric oxygen therapy, the patient's BCVA increased to 0.9 on the 14th day of diagnosing PAMM. CONCLUSION: To the best of our knowledge, this is the first case representing a patient with  PAMM triggered by fasting and cataract surgery who responded positively to hyperbaric oxygen therapy. However, triggering of PAMM by fasting is entirely unproven and that this observation occurred in a highly complex case with many other possible contributing factors. Also, the triggering of PAMM by some manipulation during surgery is equally unproven.

Role of hyperbaric oxygen therapy in patients with inflammatory bowel disease.

PURPOSE OF REVIEW: Hypoxia is a known contributor to inflammation in inflammatory bowel diseases (IBD), and a growing interest has emerged in pharmacologically targeting hypoxia response pathways to treat IBD. The most basic form of treatment for hypoxia is delivering higher amounts of oxygen to the intestinal mucosa. In this review, we summarize the evidence in support of hyperbaric oxygen therapy (HBOT), a mechanism to deliver high amounts of oxygen to tissue, for treating IBD. RECENT FINDINGS: Two phase 2 clinical trials in hospitalized ulcerative colitis patients suffering from moderate-to-severe flares have demonstrated that HBOT improves responsiveness to steroids and avoidance of rescue medical and surgical therapy. Outpatient cohort studies in perianal fistulizing Crohn's disease and fistulizing complications of the pouch have demonstrated improved healing, particularly for complex fistulae. Several systematic reviews have now been completed, and HBOT has been observed to be well tolerated with low rates of adverse events. SUMMARY: HBOT may be considered as an adjunctive treatment for hospitalized ulcerative colitis flares and Crohn's disease-related fistulae. Higher quality trials are needed to confirm efficacy.