A comparison of two hyperbaric oxygen regimens: 2.0 ATA for 120 minutes to 2.4 ATA for 90 minutes in treating radiation-induced cystitis Are these regimens equivalent?

Introduction: Hyperbaric oxygen dosing variations exist in radiation cystitis treatment. The objectives of this study were to compare response and safety rates among patients with radiation cystitis treated with different protocols: 2.0 ATA (atmospheres absolute) for 120 minutes at the University of Pennsylvania; and 2.4 ATA for 90 minutes at Hennepin Healthcare. Materials and Methods: Retrospective chart review of radiation cystitis patients treated with hyperbaric oxygen at the University of Pennsylvania (January 2010-December 2018) and Hennepin Healthcare Minnesota (January 2014-December 2018). Primary outcome was response to treatment. Complications were limited to hyperbaric-related conditions. Regression analysis was performed with ordinal logistic regression and binary logistic regression. Result: 126 patients were included in the analysis (2.0 ATA: 66, 2.4 ATA: 60). Overall response rate was 75.4% (good) and was not significantly different between protocols (good response: 2.0 ATA 72.7% vs. 2.4 ATA 78.3% p=0.74). The 2.0 ATA group required additional treatments [2.0 ATA: 45.45 ± 14.5 vs. 2.4 ATA: 40.03 ± 9.7, p<0.05]. 6.1% (2.0 ATA) and 13.3% (2.4 ATA) required tympanostomy tube placement or needle myringotomy for otic barotrauma (p=0.22). Transfusion was associated with poorer outcomes (p<0.05). Conclusion: Both groups - 2.0 ATA and 2.4 ATA - had similar response and complication rates. Blood transfusion is a negative prognostic factor for treatment outcome.

Hyperbaric oxygen therapy for the prevention of arterial gas embolism in food grade hydrogen peroxide ingestion.

Food grade hydrogen peroxide ingestion is a relatively rare presentation to the emergency department. There are no defined guidelines at this time regarding the treatment of such exposures, and providers may not be familiar with the potential complications associated with high concentration hydrogen peroxide ingestions. In this case series, we describe four patients who consumed 35% hydrogen peroxide, presented to the emergency department, and were treated with hyperbaric oxygen therapy. Two of the four patients were critically ill requiring intubation. All four patients had evidence on CT or ultrasound of venous gas emboli and intubated patients were treated as if they had an arterial gas embolism since an exam could not be followed. After hyperbaric oxygen therapy each patient was discharged from the hospital neurologically intact with no other associated organ injuries related to vascular gas emboli. Hyperbaric oxygen therapy is an effective treatment for patients with vascular gas emboli after high concentration hydrogen peroxide ingestion. It is the treatment of choice for any impending, suspected, or diagnosed arterial gas embolism. Further research is needed to determine which patients with portal venous gas emboli should be treated with hyperbaric oxygen therapy.

Vasculogenic stem cell mobilization and wound recruitment in diabetic patients: increased cell number and intracellular regulatory protein content associated with hyperbaric oxygen therapy.

Diabetic patients undergoing hyperbaric oxygen therapies (HBO(2)T) for refractory lower extremity neuropathic ulcers exhibit more than a twofold elevation (p=0.004) in circulating stem cells after treatments and the post-HBO(2)T CD34(+) cell population contains two- to threefold higher levels of hypoxia inducible factors-1, -2, and -3, as well as thioredoxin-1 (p<0.003), than cells present in blood before HBO(2)T. Skin margins obtained from 2-day-old abdominal wounds exhibit higher expression of CD133, CD34, hypoxia inducible factor-1, and Trx-1 vs. margins from refractory lower extremity wounds and expression of these proteins in all wounds is increased due to HBO(2)T (p<0.003). HBO(2)T is known to mobilize bone marrow stem cells by stimulating nitric oxide synthase. We found that nitric oxide synthase activity is acutely increased in patients' platelets following HBO(2)T and remains elevated for at least 20 hours. We conclude that HBO(2) T stimulates vasculogenic stem cell mobilization from bone marrow of diabetics and more cells are recruited to skin wounds.

CASE SERIES OF HYPERBARIC OXYGEN THERAPY FOR CENTRAL RETINAL ARTERY OCCLUSION.

PURPOSE: To retrospectively report the outcomes of patients presenting to our facility with central retinal artery occlusion and receiving therapy with hyperbaric oxygen (HBO). METHODS: This was a retrospective, chart review at a single hospital center. Patients with diagnosed central retinal artery occlusion were treated with HBO twice daily for 5 days during their inpatient stay for a total of 10 HBO treatments. Main outcome was change from the documented presenting best-corrected visual acuity to discharge best-corrected visual acuity. Thirty-nine patients with central retinal artery occlusion were included in the analysis during a 30-month period. RESULTS: Twenty-eight of 39 patients (72%) had some improvement in acuity. There was a mean of 5.05 lines of improvement using a modified Snellen chart after completing their HBO treatment course. Patients treated within 12 hours of symptom onset showed the greatest improvement in their visual acuity (6.11 mean lines of improvement). Complications of therapy included middle ear barotrauma (10/39) and confinement anxiety (1/39) and did not interfere with the therapy regimen or hospital course. CONCLUSION: This retrospective case series supports the use of emergent HBO therapy as a viable treatment option for patients with central retinal artery occlusion. Hyperbaric oxygen therapy was safely administered and well tolerated.

Esophageal Stricture Following Radiation, Concurrent Immunochemotherapy, Treated With Hyperbaric Oxygen and Dilation.

Low-dose palliative radiation may offer symptomatic relief in patients with spinal metastases from primary renal cell cancer and is unlikely to result in radiation injury. Patients with advanced malignancy requiring palliative radiation are often also receiving chemotherapy. Synergistic adverse effects resulting from combined palliative radiation and novel antiprogrammed cell death-1 (anti-PD 1) and/or multityrosine kinase inhibitors are rare. We report about a 60-year-old woman with metastatic clear-cell renal cancer, status post-left nephrectomy, with debilitating mid-back pain from metastatic tumor burden and foraminal nerve compression. Her chemotherapeutic regimen was repeatedly altered because of progression of disease until she was maintained on the anti-PD 1 checkpoint inhibitor, nivolumab. She received palliative radiation to her thoracic spine over a 2-week period, and nivolumab was then switched to cabozantinib midway through a course of palliative radiation. The patient rapidly developed severe esophagitis, progressing to esophageal stricture, and required placement of a percutaneous endoscopic gastrostomy tube. She was successfully treated with serial esophageal dilation and hyperbaric oxygen treatments to diminish inflammation and improve tissue vascularity. Concurrent use of anti-PD 1 and/or multityrosine kinase drugs may accelerate development of radiation injury regardless of radiation dosage. Radiation-induced esophageal stricture was managed successfully in this patient with serial esophageal dilation and adjuvant hyperbaric oxygen.

Plasma biomarkers in carbon monoxide poisoning.

OBJECTIVES: The severity of acute carbon monoxide (CO) poisoning is often based on non-specific clinical criteria because there are no reliable laboratory markers. We hypothesized that a pattern of plasma protein values might objectively discern CO poisoning severity. This was a pilot study to evaluate protein profiles in plasma samples collected from patients at the time of initial hospital evaluation. The goal was to assess whether any values differed from age- and sex-matched controls using a commercially available plasma screening package. METHODS: Frozen samples from 63 suspected CO poisoning patients categorized based on clinical signs, symptoms, and blood carboxyhemoglobin level were analyzed along with 42 age- and sex-matched controls using Luminex-based technology to determine the concentration of 180 proteins. RESULTS: Significant differences from control values were found for 99 proteins in at least one of five CO poisoning groups. A complex pattern of elevations in acute phase reactants and proteins associated with inflammatory responses including chemokines/cytokines and interleukins, growth factors, hormones, and an array of auto-antibodies was found. Fourteen protein values were significantly different from control in all CO groups, including patients with nominal carboxyhemoglobin elevations and relatively brief intervals of exposure. CONCLUSIONS: The data demonstrate the complexity of CO pathophysiology and support a view that exposure causes acute inflammatory events in humans. This pilot study has insufficient power to discern reliable differences among patients who develop neurological sequelae but future trials are warranted to determine whether plasma profiles predict mortality and morbidity risks of CO poisoning.