Number 4

  DOI: 10.22462/07.08.2018.15

  DOI: 10.22462/07.08.2018.14

  Severe decompression illness (DCI) is an uncommon medical issue affecting divers and results mainly from rapid surfacing using inadequate decompression protocols. Massive gas embolism with central nervous system involvement often leads to a poor prognosis, with permanent residual neurologic defects. Moreover, DCI complicated with multiple organ dysfunction syndrome (MODS) is tremendously rare and difficult to cure, although hyperbaric oxygen (HBO2) therapy following the U.S. Navy Treatment Tables is a consensus. We report a case of severe DCI with profound shock and MODS after an initial treatment with HBO2 therapy using U.S. Navy Treatment Table 6A. Following the Surviving Sepsis Campaign Guidelines, low-dose hydrocortisone was administered. Although this treatment went against recommendation of the U.S. Navy Diving Manual, it resulted in a dramatic clinical improvement. After a second round of HBO2 treatments, the patient was discharged from hospital two weeks after the diving accident. DOI: 10.22462/07.08.2018.13  

Direct traumatic optic neuropathy (TON) is a devastating condition and clinical challenge. Its adequate treatment remains controversial. Hyperbaric oxygen (HBO2) therapy has been proposed as an adjunctive treatment for eye disease but has rarely been used in optic neuropathy. The patient was a 57-year-old woman who had direct TON and brain injury after contusion injury. After receiving delayed HBO2 therapy her visual acuity got better – from hand motion to 6/60 – along with improvement of visual field and color vision. She was treated at 2.5 atmospheres absolute for 100 minutes, five times a week, for a total of 61 sessions. Our case highlights that HBO2 may be beneficial as an alternative treatment for direct TON, particularly when combined with brain injury. Although this entity is promising, further randomized controlled trials will be needed to clarify the efficacy of HBO2 in the treatment of direct TON. DOI: 10.22462/07.08.2018.12

Introduction: Hyperbaric oxygen (HBO2) therapy is infre- quently reported as a treatment for poison-induced retinal damage. We describe a case in which HBO2 therapy was used to treat suspected retinal toxicity induced by quinine. Case report: We present a case in which HBO2 was used to treat visual disturbances thought to be caused by quinine- induced retinal damage. The patient intentionally ingested undisclosed amounts of citalopram and quinine. Following a complicated hospital course, including profound shock requiring treatment with four vasopressors and a peripheral left-ventricular assist device, the patient, once extubated, reported visual abnormalities consistent with those described from quinine-induced retinal toxicity. Visual disturbances seemed to show improvement following HBO2 treatment. Several months following hospitalization visual defects continued to be present on examination. However, with corrective lenses the patient’s visual acuity was normal. No adverse events were attributed to the use of HBO2. Discussion: HBO2 for treatment of quinine-induced retinal damage is infrequently reported or studied. In the reported case, use of HBO2 appeared to be associated with substan- tial improvement in visual disturbances occurring in the setting of an overdose of quinine. The patient’s improvement is remarkable, given her retinas were also jeopardized by her profound shock. Additional data are needed to understand the risks and benefits of this ..

Background: The fetus is uniquely susceptible to carbon monoxide (CO) exposure. We present a case of severe unintentional CO poisoning in the first trimester of pregnancy. Case: A 23-year-old G5P2022 female at 11 weeks' gestational age sat in a car with the engine idling. She was unaware that the vehicle’s exhaust pipe was blocked with snow. She was found to be unresponsive, with an initial carboxyhemoglobin (COHb) concentration of 47.1%. She underwent emergent treatment with hyperbaric oxygen therapy. The remainder of her pregnancy was complicated by a diagnosis of myasthenia gravis. She delivered a full-term infant who was noted to have persistently small head circumference. Discussion: Fetal hemoglobin binds to CO more tightly than adult hemoglobin, and fetal carboxyhemoglobin concentrations are reported to exceed maternal levels. Fetal abnormalities may occur after CO poisoning in pregnancy and vary based on the gestational age of the fetus at the time of the exposure as well the chronicity of the exposure. Conclusion: Fetal survival after maternal CO exposure is possible even with significantly elevated maternal COHb concentrations, although teratogenic effects may occur depending on the timing of exposure. DOI: 10.22462/07.08.2018.10

Introduction: Decompression sickness is endemic to small- scale fishermen-divers from coastal communities in southeast Mexico; overweight and obesity are also highly prevalent in the region. Existing literature suggests it is possible that fat tissue could play a role in decompression sickness pathophysiology. Our aim in this study is to describe the association between the number and severity of DCS events treated at the hyperbaric program and fishermen-diver body mass index. Methods: In this cross-sectional study, we obtained anthropometric measurements of 105 fishermen-divers and reviewed clinical records of each participant at a hyperbaric program. Results: Average BMI among participants was 34.5±4.7, while 9.5% (n=10) were healthy-weighted, 28.6% (n=30) were overweight and 42.8% (n=65) were obese. Number of DCS events per diver was associated with BMI and severity of DCS in linear regression models. Discussion: Overweight and obesity are highly prevent- able health problems; our results suggest that an association between these conditions and the frequency and the severity of DCS are an important topic to be further considered in longitudinal prospective studies. DOI: 10.22462/07.08.2018.9

Background: Scuba divers are subjected to relatively high ambient pressures while descending. Equalizing man- euvers (e.g., Valsalva) are necessary to open the Eustachian tube (ET) and allow air into the middle ear (ME) cavity. Insufficient opening of the ET leads to ME barotrauma, which is the most common injury related to scuba diving. The study aims were to assess the incidence of ME barotrauma and to compare tympanometric parameters and stapedial reflexes in scuba divers and non-diving individuals. Material and methods: 60 scuba divers participated in the study; control consisted of 90 non-diving volunteers without a history of otolaryngologic problems. All participants were examined with the use of otoscopy and tympanometry with evaluation of ipsilateral stapedial reflexes. The group studied was surveyed regarding occurrence of ME barotrauma and diving competence. Results: 51.7% of the divers experienced ME barotrauma, the most common symptoms being earache and hearing loss. Comparison of the group studied and control revealed signifi- cantly lower ME pressure and compliance in scuba divers. In scuba divers with ME barotrauma, longer time from injury correlates directly with greater ME pressure and compliance, indicating tissue recovery. At 4,000Hz 100dB percentage of present stapedial reflexes among scuba divers was significantly lower than in controls; moreover, ..

Astronauts training for extravehicular activity (EVA) operations can spend many hours submerged underwater in a pressurized suit, called an extravehicular mobility unit (EMU), exposed to pressures exceeding 2 atmospheres absolute (ATA). To minimize the risk of decompression sickness (DCS) a 46% nitrox mixture is used. This limits the nitrogen partial pressure, decreasing the risk of DCS. The trade-off with using a 46% nitrox mixture is the increased potential for oxygen toxicity, which can lead to severe neurologic symptoms including seizures. Suited runs, which typically expose astronauts of 0.9-1.1 ATA for longer than six hours, routinely exceed the recommendation for central nervous system oxygen toxicity limits (CNSOTL) published by the National Oceanic and Atmospheric Administration (NOAA). Fortunately, in over 50,000 hours of suited training dives spanning 20 years of EVA training operations at NASA’s Neutral Buoyancy Laboratory (NBL) there has never been an occur- rence of oxygen toxicity. This lends support to anecdotal sentiment among certain members of the hyperbaric commu- nity that the NOAA CNSOTL recommendations might be overly conservative, at least for the oxygen pressure and time regime in which NBL operates. The NOAA CNSOTL recommendations are the result of expert consensus with a focus on safety and do ..

Background: Central retinal artery occlusion (CRAO) is a rare and serious ophthalmologic emergency with a bad prognosis. Hyperbaric oxygen (HBO2) treatment has been reported to improve visual acuity of CRAO patients. However, there are unknown variables for HBO2 treatment such as initiation period, number of sessions and efficacy. In this study, we aimed to investigate efficacy of HBO2 treatment in CRAO patients. Methods: Patients who had been diagnosed with CRAO and referred to our Hyperbaric Oxygen Treatment Unit with the indication of HBO2 treatment were included in the study. Patient demographics, their systemic diseases, best-corrected visual acuity (BCVA) and the time of visual loss were recorded. Oral acetazolamide and topical beta blocker treatments as well as HBO2 treatments were administered to patients as soon as possible. Patients received 20 treatments as standard. Visual acuity was examined and recorded following each HBO2 treatment administration. Results: 10 eyes (five right, five left) of 10 patients) were included in the study. While average visual acuity was LogMAR 3 before the treatment, it was measured as LogMAR 1.8 on average after treatment (P<0.05). None of the patients were observed to have neovascular glaucoma. Conclusions: HBO2 treatment is an efficacious method with few side effects and can be used in the treatment of CRAO patients. During acute ..

Purpose: The purpose of this experimental study was to investigate the effect of hyperbaric oxygen (HBO2) therapy combined with microfracture technique in the treatment of cartilage lesions. Methods: Adult Wistar rats (n=44) were divided into six groups. In Groups A, B, C and D, ICRS* grade 4 cartilage lesions were made on the femoral sulcus of both knees. Lesions were microfractured on the left knees; the right knees had no further procedure. Groups E and F had no surgery. Groups A, C and E received HBO2 therapy once a day, six days a week postopera- tively. Groups B, D and F had no HBO2 therapy. The animals in Groups A, B, E and F were sacrificed after two weeks; Groups C and D were sacrificed after four weeks. Semiquantitative scale – including filling of defect (microfracture hole), reparative tissue thickness, cell morphology and subchondral bone maturation – was used for evaluation. The Mann-Whitney test was used to compare individual and total scores. Results: Total scores of the two-week group with adjuvant HBO2 therapy were significantly higher (P=0.0007) than the two-week standard treatment group. Except for subchondral bone maturation, individual scores were significantly higher in the two-week group with adjuvant HBO2 therapy. Total scores of the four-week groups were ..

Hyperbaric oxygen (HBO2) is widely used in clinical settings for many disease treatments. To investigate the potential effects of hyperbaric oxygen on patients with slow coronary flow (SCF) we retrospectively analyzed 98 patients who were diagnosed with SCF by coronary artery angiography. Of these, 50 patients received conventional treatment only (control group; the other 48 patients received hyperbaric oxygen treatment for four weeks in addition to the routine therapy (HBO2 group). By using gated myocardial perfusion tomography examination before and after treatment, we observed that 71 out of 148 (47.9%) subsegments of injured myocardium improved in the control group, while 108 out of 151 (71.5%) subsegments of injured myocardium improved in the HBO2 group (P<0.05). Furthermore, the peak filling rate (PFR), time of peak fil ing rate (TPFR) and mean filling rate during the first one-third of the filling time (MFR/3) were all significantly improved in HBO2-treated patients compared to those who received conventional treatment only. However, we did not detect any significant effects of only treatment on left ventricular end diastolic volume (LVEDV), left ventricular end systolic volume (LVESV), nor on left ventricular ejection fraction (LVEF). Our results indicate that hyperbaric oxygen therapy can be a beneficial and effective medication to improve myocardial ..

Purpose: To determine ocular refraction, corneal thickness, corneal radius, corneal power, corneal astigmatism and intraocular pressure in patients before and immediately after repeated hyperbaric oxygen (HBO2) exposures twice a week during six weeks of HBO2 therapy. Methods: 23 patients received HBO2 therapy at 2.4 ATA for 90 minutes daily in monoplace chambers for six weeks, five days a week. The Topcon TRK-1P instrument was installed next to the hyperbaric chambers to record the ocular measurements. Results: A gross myopic shift developed at -0.95 ± 0.54 D (P < 0.001) in the right eye and -0.95 ± 0.53 D (P < 0.001) in the left eye during the six weeks of treatment. Myopic shift reversion, corneal thinning and reduced intraocular pressure appeared as immediate effects after a single HBO2 exposure, but resolved before the patients attended for the next measurement visit. Conclusions: Ocular variables were influenced by both cumulative and transient short-term effects during the HBO2 therapy. The short-term effects showed that the point of time for performing the ocular measurements after HBO2 exposure might influence the result and must be considered before making relevant comparisons among studies. DOI: 10.22462/07.08.2018.3

Introduction: Hyperbaric oxygen (HBO2) therapy is used to promote healing in select problem wounds. Transcutaneous oxygen measurement (TCOM) can be used to predict the re- sponse of these wounds to HBO2, with in-chamber TCOM values shown to be the most predictive. We evaluated the use of in-chamber TCOM values to determine optimal treatment pressure. Methods: A retrospective review was completed of patients undergoing HBO2 therapy for a lower-extremity wound and who had in-chamber TCOM. Data collected included TCOM values, treatment profile, and patient outcome. Results: A total of 142 patients were identified. The overall results demonstrated healing in 59%, minor amputation (below ankle) in 11.3%, and major amputation (above ankle) in 16.2% of patients. 79.3% of patients at 2 atmospheres absolute (ATA) and 86.6% of patients at 2.4 ATA had transcutaneous oxygen pressure (TcPO2) values >=250mmHg. Among those with TcPO2 <250mmHg at 2 ATA, 41% attained TcPO2>250mmHg at 2.4 ATA. Among those treated at 2 ATA the healing rate was 70.6% if TcPO2 >250mmHg, and 11.8% if TcPO2 <250mmHg (P<0.001). Among those treated at 2.4 ATA the healing rate was 33.3% if TcPO2 >250mmHg and 14.3% if TcPO2 <250mmHg (p<0.001). Discussion: Determining optimal therapeutic pressure for patients undergoing HBO2 is important to maximize ben- efit and minimize risk. This study indicates that in-chamber ..

Purpose: Soft-tissue reconstruction is complicated by ischemia and reperfusion injury. Animal trials have documented the independent healing benefits of hyperbaric oxygen preconditioning (HBOP) and stem cell delivery in cutaneous flaps. We explored the role of HBOP and stem cell delivery in flap preconditioning and survival. Methods: We designed a randomized controlled trial to assess the effects of hyperbaric oxygen preconditioning and stromal vascular fraction (SVF) delivery on flap survival. Of the first 24 guinea pigs, six received neither HBOP nor injections, and six underwent HBOP without injections. Of the remaining 12 animals, six received SVF or saline injections in the absence of HBOP. The final six animals received autologous SVF injections or saline injections followed by four HBOP treatments. To enhance clinical relevance, a group of 6 animals underwent HBOP prior to SVF or saline injections. Thereafter, an unfavorably designed cutaneous flap was elevated and assessed via study-blinded observer, as well as by quantification of TUNEL-positive cells. Results: Distal necrosis of the tissue flap was more ex- tensive in the no-intervention group (45% of flap). Flaps treated with HBOP only and those treated with SVF injections demonstrated only 38.2% and 27.1% distal necrosis. The most significant difference occurred in the combination HBOP and SVF ..