Number 4

[ White paper ] DOI Number: 10.22462/10.12.2020.15

[ Letter ] DOI Number: 10.22462/10.12.2020.14

The use of grafts and flaps serves as an integral tool in the armamentarium of the reconstructive surgeon. Proper planning and surgical judgment are critical in the ultimate success of these procedures. However, there are situations when grafts and/or flaps can become compromised and require urgent intervention for salvage. These instances can include irradiated or otherwise hypoxic wound beds, excessively large harvested grafts, random flap ischemia, venous or arterial insufficiency, and ischemia-reperfusion injury. Alternatively, compromised grafts and flaps can be inadvertently created secondary to trauma. It is in these types of cases, hyperbaric oxygen (HBO2) therapy can serve as a useful adjunct in the salvage of compromised flaps and grafts. This review outlines the extensive basic science and clinical evidence available in support of the use of HBO2 therapy for compromised grafts and flaps. The literature demonstrates the benefit of adjunctive HBO2 therapy for multiple types of grafts and flaps with various etiologies of compromise. HBO2 therapy can enhance graft and flap survival by several methods including decreasing the hypoxic insult, enhancing fibroblast function and collagen synthesis, stimulating angiogenesis and inhibiting ischemia-reperfusion injury. The expedient initiation of hyperbaric oxygen therapy as soon as flap or graft compromise is identified ..

Hyperbaric oxygen (HBO2) therapy has been demonstrated to have beneficial effects on the early stages of steroid-associated osteonecrosis (SAON) of the femoral head. Since high HBO2 pressure (e.g., 2.4-2.5 atmospheres absolute/ATA) has been commonly considered to have a greater ability to restore tissue oxygenation in the femoral head than low pressure (e.g., 1.6 ATA), the latter HBO2 protocol is rarely used for SAON treatment. In this paper, we present the case of a 36-year-old female diagnosed with bilateral early stage (Association for Research on Osseous Circulation, ARCO stage II) SAON caused by steroid therapy for neuromyelitis optica spectrum disorder (NMOSD). Because the patient could not endure high HBO2 pressures, the treatment pressure was adjusted to 1.6 ATA, which was the highest pressure the patient could withstand. After 20 treatment sessions, her symptoms were relieved significantly. Her visual analog score (VAS: using a 0-10 score) decreased from 7 to 2, and after 50 treatment sessions her symptoms disappeared almost completely. A significant improvement was also observed radiologically by computed tomography (CT) and magnetic resonance imaging (MRI) examinations. This case study provides a potential HBO2 treatment protocol with reduced pressure for early-stage femoral head necrosis. Further research is needed to validate this ..

Arterial gas embolism is a well-described and frequently seen injury encountered in both civilian and military diving operations. It is becoming increasingly reported and potentially increasingly more common in the hospital environment as a complication of more frequent gastroenterology procedures. We present a case of a 49-year-old, active-duty female who developed significant left-sided neurological deficits manifesting as diffuse left-sided weakness, subjective confusion, and severe headache following esophagogastroduodenoscopy. With increased clinical suspicion for arterial gas embolism, the patient was evaluated by the hyperbaric medicine team at our facility and subsequently treated to near-resolution of symptoms by multiple hyperbaric oxygen treatments. This case highlights the importance of considering this rare complication during or following common invasive procedures. Furthermore, the unique training and experience of physicians with expertise in diving medicine and their ability to recognize these types of injury in the hospital setting highlights the importance of continued training in these fields within Military Medicine in addition to civilian Undersea and Hyperbaric Medicine fellowships. DOI Number: 10.22462/10.12.2020.11

Neuroinflammation plays an important role in brain damage after acute carbon monoxide poisoning (ACOP). The nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing (NLRP) 3 inflammasome triggers the activation of inflammatory caspases and maturation of interleukin (IL)-1β and -18, and has been linked to various human autoinflammatory and autoimmune diseases. In this study we investigated the effects of hyperbaric oxygen (HBO2) on NLRP3 inflammasome activation after ACOP. Mice were randomly divided into four groups: sham group (exposure to normobaric air – i.e., 21% O2 at 1 atmosphere absolute); HBO2-only group; CO + normobaric air group; and CO + HBO2 group. Cognitive function was evaluated with the Morris water maze; myelin injury was assessed by Fluoro-Myelin GreenTM fluorescent myelin staining and myelin basic protein (MBP) immunostaining; and mRNA and protein levels of NLRP3 inflammasome complex proteins were measured by quantitative real-time PCR and Western blot, respectively. Additionally, serum and brain levels of IL-1β and -18 and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase were determined by enzyme-linked immunosorbent assay. It was found that HBO2 improved learning and memory, and alleviated myelin injury in mice subjected to acute CO exposure. Furthermore, HBO2 decreased NLRP3, absent in melanoma 2 (AIM2), caspase-1, and apoptosis-associated speck-like protein ..

Platelets are the most easily altered type of peripheral blood cell in decompression sickness (DCS), which can feature decreased platelet count and the appearance of platelet microparticles in plasma. We hypothesized that DCS results in platelet activation in the bloodstream. The present study was carried out on 45 rabbits. The platelet count and concentration of plasma platelet markers were determined in 35 rabbits; the platelet shape was observed under scanning electron microscope in 10 rabbits. All indexes were collected at two points: 24 hours before the simulated dive and 30 minutes after the simulated dive. Platelet count decreased noticeably after DCS, from 380.10 ± 73.61 (G/L) to 330.23 ± 115.72 (G/L), a change of approximately -13.49 ± 25.57 (%). Platelet count was further decreased in the severe DCS group (a change of -45.99 ± 18.57%). Platelet count after DCS was proportional to the survival time of the rabbits after DCS. The concentration of two plasma platelet markers (PF4 and BTG) did not demonstrate statistically significant change at 30 minutes after DCS. However, platelet shape was changed, and the following features were observed: oblong, distortion, flattening shape, sticking together, mixing of membrane, and abundance of pseudopods with a 100- to ..

Background: Hyperbaric oxygen (HBO2) therapy was introduced nearly 300 years ago. However, its effect on thrombus formation is unclear. This may be because platelet and coagulation functions are unstable, yielding variable results; hence, accurate measurement is difficult. Our study aimed to analyze changes in thrombus formation before and after HBO2 therapy by using a total thrombus formation analysis system (T-TAS). Methods: Six patients were prescribed HBO2 therapy for skin and soft tissue ulcers, and necrotic fasciitis. Blood samples were collected immediately before and after treatment. Then samples were put into a reservoir that connected to AR-chip to assess changes in the thrombus formation ability of both platelets and coagulation factors. We examined the differences in the thrombus formation ability using T-TAS. Time until the onset of white thrombus formation (T10) and complete occlusion of the capillary (T80) were analyzed by a two-way repeated measure analysis of variance (ANOVA). Results: The duration to pressure increase of samples after HBO2 therapy was longer than the duration before HBO2 therapy (p<0.05). This suggests decreased clot adhesiveness to the inner surface of the simulated blood vessel and reduced clot formation ability. Conclusions: The results for T10 and T80 suggest that HBO2 therapy reduced thrombus formation ability ..

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 ..

Objectives: To clinically and microbiologically evaluate the effects of hyperbaric oxygen (HBO2) therapy in addition to full-mouth ultrasonic subgingival debridement (FM-UD), in the initial treatment of chronic periodontitis.  Methods: Twenty patients presenting moderate to severe generalized forms of chronic periodontitis were included in a three-month randomized, parallel-group, single-blinded, prospective study. At baseline patients were randomly assigned to two treatment groups [Test Group (FM-UD+HBO2) and Control Group (FM-UD)]. Both groups were treated with an FM-UD session. Ten HBO2 sessions (one session per day for 10 days at a pressure of 2.5 ATA) were additionally administered to the Test Group. Soft tissues parameters [probing pocket depth (PPD), bleeding on probing (BOP), clinical attachment level (CAL) and visible plaque index (VPI)] were assessed at baseline (immediately before FM-UD treatment), after two weeks, after six weeks and at three months. For each patient, a site presenting PPD ≥ 6mm and positive BOP was selected as a qualifying site (QS), to be monitored clinically (at T0, T1, T2 and T3) and microbiologically (at T0, T1 and T3). Results: There were no statistically significant differences between the two groups for any clinical parameter analyzed after three months, except for BOP, which was significantly (p < 0.05) reduced in the ..

Introduction: The treatment of avascular necrosis of the femoral head (AVNFH) is based on invasive (e.g., core decompression) and non-invasive methods (e.g., hyperbaric oxygen therapy – HBO2). The purpose of the present study is to evaluate the effect of HBO2 on the quality of life (QoL) of patients with AVNFH. Methods: This was a prospective observational non-controlled study of patients with AVNFH treated by HBO2. It was conducted, with the use of Steinberg scale, on 73 patients with AVNFH Stage I or II who were treated with HBO2. Patients’ QoL was assessed with EuroQol-5D-5L (EQ), Harris Hip Score (mHHS), MAHORN (MHOT), and VAS, in three different phases: before HBO2; after the completion of the first phase (20 HBO2 sessions, up to two months); and after the completion of the second phase (20 HBO2 sessions, up to two months after the first phase). A reassessment was made on the completion of each phase. Ratings were also made after the completion of each phase, over the first five months of follow-up. Results: All 73 patients (67.1% males, 32.9% females, mean age: 40.34, SD ± 9.99) participated in the study. Steinberg scale, mean EQ (F (1, 57) = 25.18, η2 = .306 and F (1, ..

A diver practicing controlled emergency ascent training on the island of Guam suffered bilateral pneumothorax, pneumomediastinum, coronary arterial gas embolism, and developed multiple organ dysfunction syndrome. Due to limitations of available resources he was medically managed in the intensive care unit until he could be transferred to University of California San Diego for definitive management. We provide an account of our management of the patient, the pathophysiology of injury as well as a review of the safety of recreational diving skills training, current standards of practice and potential pitfalls when considering proper management of a critically injured diver. DOI Number: 10.22462/10.12.2020.4

With the increasing popularity of recreational scuba diving, rare complications are becoming more commonly encountered. Although diving is generally safe, novice divers may be unfamiliar with the potential hazards of scuba diving and the resulting sequelae. Dive-related injuries are commonly due to barotrauma or from breathing gas at increased pressures, resulting in decompression illness (DCI), a term that includes both decompression sickness (DCS) and arterial gas embolism (AGE). Symptoms can range from minor aches and pains to neurologic or cardiopulmonary complications resulting in death. Clinical symptoms and diagnosis may initially go unrecognized and can present in a delayed manner, often remote to the diving location. When DCI is suspected standard treatment with hyperbaric oxygen (HBO2) therapy should be considered immediately. Current literature questions the efficacy of delayed HBO2 therapy longer than 24-48 hours after symptom onset. Here we present a case of two divers who simultaneously experienced DCS and were both successfully treated after receiving delayed HBO2 therapy nearly eight days after initiation of symptoms. DOI Number: 10.22462/10.12.2020.3 

Background: The popularity of apneic diving is continually growing. As apnea diving substantially burdens the cardiovascular system, special focus is warranted. Regarding inflammation processes and associated inflammatory-related diseases (e.g., cardiovascular diseases), eicosanoids play an important role. This study aims to investigate polyunsaturated fatty acids (PUFAs) and eicosanoids in voluntary apnea divers, and so to further improve understanding of pathophysiological processes focusing on proinflammatory effects of temporarily hypercapnic hypoxia. Methods: The concentration of PUFAs and eicosanoids were investigated in EDTA plasma in apnea divers (n=10) before and immediately after apnea, 0.5 hour and four hours later, applying liquid chromatography-tandem mass spectrometry (LC-MS/MS). Results: Mean age was 41±10 years, and divers performed a mean breath-hold time of 317±111 seconds. PUFAs, eicosanoids and related lipids could be classified in four different kinetical reaction groups following apnea. The first group (e.g., Ω-6 and Ω-3-PUFAs) showed an immediate concentration increase followed by a decrease below baseline four hours after apnea. The second group (e.g., thromboxane B2) showed a slower increase, with its maximum concentration 0.5 hour post-apnea followed by a decrease four hours post-apnea. Group 3 (9- and 13-hydroxyoctadecadienoic acid) is characterized by two concentration increase peaks directly after apnea and four hours afterward compared to baseline. Group 4 ..

Introduction: Pulmonary fluid shifts can occur while scuba diving. Such shifts, generally thought to be rare, may result in a life-threatening phenomenon known as immersion pulmonary edema (IPE). This study aims to better classify the normal physiology of diving using ultrasound (US) to determine if these fluid shifts occur routinely during commercial diving work at the NASA Neutral Buoyancy Laboratory (NBL). Methods: Chest US was performed on commercial divers prospectively pre- and post-dive to evaluate the presence of B-lines in a total of 12 intercostal points on the anterior, posterior, and lateral chest wall. The number of B-lines at each anatomic site was recorded and scored by two independent reviewers. An increase in the number of B-lines postdive was considered a positive result. Results: There were 67 exposures; 39 (58%) had an increase of one or more B-lines post dive; 64% of the female exposures and 57% of the male exposures were positive for B-lines post-dive, suggesting no difference across gender (Fisher’s exact; p = 0.763). After the dive, all divers remained asymptomatic. Conclusions: From our results, fluid shifts can be viewed as a normal, transient, and physiologic process in commercial divers. This correlation can be compared to the formation of low-grade venous gas emboli (VGE) from decompression that does not result in decompression sickness. Further study of US B-lines in symptomatic divers may ..