Cases Of Decompression Illness Research Articles

Transcranial doppler to detect high-risk PFO and predict decompression illness in divers

Abstract Background It has not yet been clearly demonstrated whether it is feasible to diagnose patent foramen ovale (PFO) using transcranial doppler (TCD) and to use it in strategies to prevent decompression illness (DCI) in self-contained breathing apparatus (SCUBA) divers. Purpose DIVER-PFO study confirmed that high-risk PFO is associated with an increased risk of DCI in SCUBA divers. In this prespecified post-hoc analysis, we aimed to prospectively evaluate the accuracy of TCD to diagnose high-risk PFO and to predict the occurrence of DCI. Methods Eighty-two consecutive divers (mean age; 41 years, male 80.5%) underwent transesophageal echocardiogram (TEE) and TCD with a saline bubble test to determine the presence of PFO and were subsequently divided into high-risk and low-risk groups by TEE findings. Divers in the high-risk PFO group included those with the following conditions: PFO with atrial septal aneurysm, hypermobility, PFO size ≥2 mm, or right to left shunt at resting state. The enrolled divers were then followed-up using a self-reported questionnaire through e-mail or telephone interview for 3 years, while they were blinded to their PFO status. The primary endpoint of the study was PFO-related DCI, comprising cases of cutaneous or neurologic DCI, DCI symptoms requiring hyperbaric chamber therapy, DCI symptoms within 30 minutes after surfacing, or unexplained death occurring within 2 weeks after diving. Results PFO was detected in 47 (57.3%) and 59 (72.0%) divers by TCD and TEE, respectively. Diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of TCD were 68.3%, 67.8%, 69.6% 85.1%, and 45.7% for the diagnosis of PFO, and 65.9%, 82.8%, 56.6%, 51.1% and 85.7% for the diagnosis of high-risk PFO, respectively. PFO-related DCI occurred in 9 divers in the PFO group (PFO vs non-PFO: 6.4 vs 0.7 incidences per 10,000 person dives; p=0.03) during a mean follow-up of 25.6 months. Integrated time-dependent Area Under the Curves for TCD and TEE to predict DCI occurrence using Cox’s proportional hazards regression model were 0.714 and 0.675, respectively. Conclusions TCD was moderately accurate to diagnose high-risk PFO in divers. However, it predicted DCI as much as TEE.Study flowIncidence of DCI in the PFO vs No PFO

Decompression illness in Finnish technical divers: a follow-up study on incidence and self-treatment.

Technical diving is increasing in popularity in Finland, and therefore the number of decompression illness (DCI) cases is also increasing among technical divers. Although hyperbaric oxygen treatment (HBOT) remains the standard of care, there are anecdotal reports of technical divers treating mild DCI symptoms themselves and not seeking a medical evaluation and possible recompression therapy. This study aimed to make an epidemiologic inventory of technical diving-related DCI symptoms, to establish the incidence of self-treatment and to determine the apparent effectiveness of different treatment methods. A one-year prospective survey with online questionnaires was conducted. Fifty-five experienced and highly trained Finnish technical divers answered the survey and reported their diving activity, DCI symptoms, symptom treatment, and treatment outcome. Of the reported 2,983 dives, 27 resulted in symptoms of DCI, which yielded an incidence of 91 per 10,000 dives in this study. All of the reported DCI symptoms were mild, and only one diver received HBOT. The most common self-treatments were oral hydration and rest. First aid oxygen (FAO2) was used in 21% of cases. Eventually, none of the divers had residual symptoms. The incidence of self-treated DCI cases was 27 times higher than that of HBO-treated DCI cases. There is a need to improve divers' awareness of the importance of FAO2 and other recommended first aid procedures and to encourage divers to seek medical attention in case of suspected DCI.

Decompression illness in Finnish technical divers: a follow-up study on incidence and self-treatment

Introduction: Technical diving is increasing in popularity in Finland, and therefore the number of decompression illness (DCI) cases is also increasing among technical divers. Although hyperbaric oxygen treatment (HBOT) remains the standard of care, there are anecdotal reports of technical divers treating mild DCI symptoms themselves and not seeking a medical evaluation and possible recompression therapy. This study aimed to make an epidemiologic inventory of technical diving-related DCI symptoms, to establish the incidence of self-treatment and to determine the apparent effectiveness of different treatment methods. Methods: A one-year prospective survey with online questionnaires was conducted. Fifty-five experienced and highly trained Finnish technical divers answered the survey and reported their diving activity, DCI symptoms, symptom treatment, and treatment outcome. Results: Of the reported 2,983 dives, 27 resulted in symptoms of DCI, which yielded an incidence of 91 per 10,000 dives in this study. All of the reported DCI symptoms were mild, and only one diver received HBOT. The most common self-treatments were oral hydration and rest. First aid oxygen (FAO2) was used in 21% of cases. Eventually, none of the divers had residual symptoms. Conclusions: The incidence of self-treated DCI cases was 27 times higher than that of HBO-treated DCI cases. There is a need to improve divers’ awareness of the importance of FAO2 and other recommended first aid procedures and to encourage divers to seek medical attention in case of suspected DCI.

What is the Best Therapeutic Strategy for Decompression Illness? First Aid Oxygen Inhalation and Hyperbaric Oxygen Therapy

Decompression illness (DCI), a syndrome following inadequate reduction in environmental pressure, has two forms: decompression sickness and arterial gas embolism after pulmonary barotrauma. Recompression therapy using oxygen, a kind of hyperbaric oxygen therapy, has been considered the gold standard treatment for DCI, although there is no randomized controlled trial evidence for its use. We evaluated the effectiveness of recompression therapy in treating DCI by reviewing the reported therapeutic results of serious DCI, especially neurological disorders. Early or ultra-early recompression therapy did not dramatically improve clinical recovery from DCI symptoms, including spinal cord disorders. In contrast, early first aid normobaric oxygen inhalation highly improved or stabilized clinical conditions of DCI. Based on these clinical results, the international committee for hyperbaric and diving medicine has stated that cases of mild DCI may be managed without recompression therapy. Further work is needed to clarify the clinical utility of recompression therapy for spinal injury as a common symptom of DCI. We also point out that the Japanese decree "Ordinance on Safety and Health of Work under High Pressure", which describes work under hyperbaric environments, has some serious issues and should be amended on the basis of scientific evidence.

Decompression illness (DCI) in Finland 1999-2018: Special emphasis on technical diving.

This is the first published study on decompression illness (DCI) and its treatment in Finland. Diving conditions are demanding, as even in the summer the water temperature below 20 meters' sea/fresh water (msw/mfw) is 4-10°C. Technical diving has become more popular over the years, so the emphasis of this study was to describe DCI in technical divers and compare it with non-technical recreational divers. This study includes by estimation over 95% of all hyperbaric oxygen-treated DCI patients during the years 1999-2018 (n = 571). The cases were divided into technical divers (n = 200) and non-technical divers (n = 371). We focused on the differences between these two groups. Technical diving was defined as the usage of mixed breathing gases, closed circuit rebreather diving or planned decompression diving. The mean annual number of treated DCI cases in Finland was 29 (range 16-38). The number of divers treated possibly indicate a shift towards technical diving. Technical dives were deeper and longer and were mainly performed in cold water or an overhead environment. Technical divers were more likely to utilize first aid 100% oxygen (FAO2) and sought medical attention earlier than non-technical divers. Symptom profiles were similar in both groups. Recompression was performed using USN Treatment Table Six in the majority of the cases and resulted in good final outcome. Eighty two percent were asymptomatic on completion of all recompression treatment(s). This 20-year observational study indicates a shift towards technical diving, and hence a more demanding and challenging style of diving among Finnish divers, with a surprisingly constant number of DCI cases over the years. There is still need for improvement in divers' education in use of FAO2 for DCI symptoms. Fortunately, the outcome after recompression therapy is generally successful.

Increasing prevalence of vestibulo-cochlear decompression illness in Malta – an analysis of hyperbaric treatment data from 1987–2017

Scuba diving is a big part of the tourism sector in Malta, and all the cases of decompression illness (DCI)are treated within the single hyperbaric referral centre in the country. This retrospective analysis reviews all the medical records of divers with DCI in Malta within the 30-year period between 1987 to 2017 who required recompression therapy with hyperbaric oxygen. There were 437 discrete cases of DCI managed with recompression therapy. Amongst DCI subtypes, the prevalence of musculo-skeletal DCI is decreasing, whereas that of vestibulo-cochlear DCI is increasing. The increasing prevalence of vestibulo-cochlear DCI may be due to a change in diving practices in Malta.

AN OBSERVATIONAL REGISTER ON DECOMPRESSION ILLNESS DURING RECREATIONAL DIVING ACTIVITY IN MALDIVES

Introduction: The decompression illness (DCI) is an infrequent event and the exactincidence is still unknown and not uniformly established. The aims of our register isa prospective observational study on recreational diving activities.Materials and methods: A questionnaire to collect data related to diving experienceand medical characteristics has been administered. When a DCI occurred, data on thesymptoms, physical conditions and of current dive and of the previous 48 hours diveswere registered. At the same time, to obtain a case-control group similar data werecollected about 5 asymptomatic components of the same diving group.Results: Among 6th October 2018 to 9th May 2019, 248 subjects has been registered;the total amount of dives by the 248 subjects was 5,331. A significant datum on theanalysis of cohort is represented by Body Mass Index (BMI) calculation; the meanBMI of studied subjects is above superior limits of normal values; and particularlysignificant is the higher value of BMI in males than females.During the 5,331 dives, 9 DCI events were reported with a rate of 1.6/1,000 dives.Seven of these cases could be classified as type 1 (with cutaneous and muscular involvement)and 2 as type 2 (with neurological symptoms). However, all the eventswere self-limited and regressed in short time.DCI events seem to be predominantly present in male and overweight (BMI > 25)subjects. The DCI cases, showed a deeper dive (even if not statistically significant),had the same length and reported higher perception of fatigue than controls.Conclusions: Our data confirm a low incidence of these events, generally of mildseverity. For these cases a local treatment with oxygen normobaric administration,general support, and hydration obtained a complete resolution of symptoms in a shorttime.Our register has allowed us to collect also data on population engaged in recreationaldiving activity. We emphasize the importance of greater medical control in the subjectswho perform diving activities, particularly in presence of some cardiovascular riskfactors, such as an overweight BMI value.Key words: Diving–decompression illness–Body Mass Index–cardiovascular risk factors

A survey of scuba diving-related injuries and outcomes among French recreational divers.

Few studies are available to appreciate the broad spectrum of dive-related injuries (DI), which are not limited to decompression illness (DCI) and fatalities. Studies supporting injury-management efficacy from early recognition to first-aid, final treatment and outcome are also lacking. This study aims at making an epidemiologic inventory of DI among French scuba divers. This online, retrospective, cross-sectional survey analyzed self-reported symptoms, context of occurrence, initial response and outcome. The relationships between symptoms and diver characteristics were assessed and severity scores created from the reports. A total of 799 divers responded, of whose questionnaires 784 were sufficiently complete to be analyzed. Approximately one-third (35%) of respondents had never experienced a DI. DCI-like symptoms represent a small fraction of DIs, the most commonly reported being ear barotrauma. Self-reported symptom rates decreased with increasing age and male sex. The ranking dive leader was the primary care provider in 58% of reports and 32% of injured divers never sought help. Management decisions (first aid and/or hyperbaric oxygen treatment) were related to the severity score. Complete resolution was achieved in 84 (74%) of 114 DCI cases, whilst mild (n = 22, 19%) and severe (n = 8, 7%) residual symptoms were reported. One in 10 divers who did not seek treatment for symptoms believed to be related to DCI declared some residual symptoms. Based on these results, diving injury rates may be higher than previously reported. However, the most frequent symptoms appear to be of only a modest nature.

A survey of scuba diving-related injuries and outcomes among French recreational divers

Introduction: Few studies are available to appreciate the broad spectrum of dive-related injuries (DI), which are not limited to decompression illness (DCI) and fatalities. Studies supporting injury-management efficacy from early recognition to first-aid, final treatment and outcome are also lacking. This study aims at making an epidemiologic inventory of DI among French scuba divers. Methods: This online, retrospective, cross-sectional survey analyzed self-reported symptoms, context of occurrence, initial response and outcome. The relationships between symptoms and diver characteristics were assessed and severity scores created from the reports. Results: A total of 799 divers responded, of whose questionnaires 784 were sufficiently complete to be analyzed. Approximately one-third (35%) of respondents had never experienced a DI. DCI-like symptoms represent a small fraction of DIs, the most commonly reported being ear barotrauma. Self-reported symptom rates decreased with increasing age and male sex. The ranking dive leader was the primary care provider in 58% of reports and 32% of injured divers never sought help. Management decisions (first aid and/or hyperbaric oxygen treatment) were related to the severity score. Complete resolution was achieved in 84 (74%) of 114 DCI cases, whilst mild (n = 22, 19%) and severe (n = 8, 7%) residual symptoms were reported. One in 10 divers who did not seek treatment for symptoms believed to be related to DCI declared some residual symptoms. Conclusion: Based on these results, diving injury rates may be higher than previously reported. However, the most frequent symptoms appear to be of only a modest nature.

Pulmonary barotrauma: assessment and investigation in divers

Decompression illness (DCI) is an uncommon problem but can be significant in terms of morbidity and, very rarely, mortality. The mechanisms of DCI are pulmonary barotrauma and decompression sickness due to inert gas supersaturation. After the initial management phase, identification of predisposing factors is important to help advise divers regarding future risk and avoidance. Here we present four cases of DCI where pulmonary barotrauma was the likely causative mechanism. We highlight the important features in assessment for pulmonary barotrauma and advising divers on the risk of a recurrence.

First Aid Oxygen Treatment for Decompression Illness in the Goat After Simulated Submarine Escape.

Personnel responding to a distressed submarine incident require information on likely casualty levels and the severity and progression of decompression illness (DCI). Recompression may not be immediately available. First aid oxygen (FAo₂) can be administered; however, there is no direct evidence of its efficacy in this scenario. Trials were conducted between 2004 and 2006. Goats exposed to raised pressure for 24 h ('saturation') were either returned directly to atmospheric pressure (Phase A, N = 40) or exposed to simulated submarine escape at a depth of 656 ft (200 m; assumed seawater density = 1019.72 kg · m(-3); Phase B, N = 39). The pressure during saturation was selected to provoke 50% DCI. Cases of DCI were randomly assigned to receive FAo₂or air. DCI cases were: limb pain in 39 subjects, neurological in 6, respiratory in 4, and pulmonary barotrauma in 1 subject. In Phase A, 5/12 subjects in the FAo₂group and 0/11 in the air control group achieved permanent resolution of DCI. In Phase B, 6/8 subjects in the FAo₂group and 5/8 in the air control group achieved permanent resolution. In both Phases, levels of venous gas bubbles reduced sooner with FAo₂. Of three cases of neurological DCI receiving FAo₂, two showed permanent resolution. In total, four cases of respiratory DCI occurred; none of these resolved, with three being treated with FAo₂and one in the air control. Oxygen can be an effective first aid measure for DCI following submarine escape. However, it should not be used as a replacement for recompression therapy.

An Atypical Case of Taravana Syndrome in a Breath-Hold Underwater Fishing Champion: A Case Report

Dysbaric accidents are usually referred to compressed air-supplied diving. Nonetheless, some cases of decompression illness are known to have occurred among breath-hold (BH) divers also, and they are reported in the medical literature. A male BH diver (57 years old), underwater fishing champion, presented neurological disorders as dizziness, sensory numbness, blurred vision, and left frontoparietal pain after many dives to a 30–35 meters sea water depth with short surface intervals. Symptoms spontaneously regressed and the patient came back home. The following morning, pain and neurological impairment occurred again and the diver went by himself to the hospital where he had a generalized tonic-clonic seizure and lost consciousness. A magnetic resonance imaging of the brain disclofsed a cortical T1-weighted hypointense area in the temporal region corresponding to infarction with partial hemorrhage. An early hyperbaric oxygen therapy led to prompt resolution of neurological findings. All clinical and imaging characteristics were referable to the Taravana diving syndrome, induced by repetitive prolonged deep BH dives. The reappearance of neurological signs after an uncommon 21-hour symptom-free interval may suggest an atypical case of Taravana syndrome.

Decompression Illness: Clinical Aspects of 5278 Consecutive Cases Treated in a Single Hyperbaric Unit

BackgroundDecompression illness (DCI) is a major concern in pressure-related activities. Due to its specific prerequisite conditions, DCI is rare in comparison with other illnesses and most physicians are inexperienced in treatment. In a fishery area in northern China, during the past decade, tens of thousands of divers engaged in seafood harvesting and thousands suffered from DCI. We established a hyperbaric facility there and treated the majority of the cases.Methods and ResultsA total of 5,278 DCI cases were admitted in our facility from February 2000 through December 2010 and treated using our recompression schedules. Cutaneous abnormalities, joint and muscular pain and neurological manifestations were three most common symptoms. The initial symptom occurred within 6 h after surfacing in 98.9% of cases, with an overall median latency of 62 min. The shorter the latent time, the more serious the symptoms would be (P<0.0001). Nine cases died before recompression and 5,269 were treated using four recompression schedules, with an overall effectiveness rate of 99.3%. The full recovery rate decreased with the increase of the delay from the onset of symptoms to the treatment (P<0.0001).ConclusionsDCI presents specific occurrence rules. Recompression should be administered as soon as possible and should never be abandoned irrespective of the delay. The recompression schedules used were effective and flexible for variety conditions of DCI.

Decompression Illness Medically Reported by Hyperbaric Treatment Facilities: Cluster Analysis of 1929 Cases

The term decompression illness (DCI) describes maladies resulting from inadequate decompression, but there is little consensus concerning clinically useful DCI subclasses. Our aim was to explore an objective DCI classification using multivariate statistics to assess naturally associated clusters of DCI manifestations. We also evaluated their mapping onto other DCI classifications and investigated the association with therapeutic outcome. We defined the optimal number of clusters using "two-step" cluster analysis and Bayesian information criterion with confirmation by hierarchical clustering with squared Euclidian distances and Ward's method. The data were 1929 DCI cases reported by hyperbaric chambers to the Divers Alert Network (DAN America) from 1999-2003. Four robust and highly significant clusters of DCI manifestations were demonstrated containing 300, 741, 333, and 555 patients. Each cluster had characteristic manifestations. Cluster 1 was effectively pain only. For Cluster 2, characteristic manifestations included numbness, paresthesia, and decreased skin sensitivity; for Cluster 3, malaise, paralysis, muscular weakness, and bladder-bowel dysfunction; and for Cluster 4, hearing loss, localized skin swelling, tinnitus, skin rash and mottling, confusion, dyspnea/chokes, muscular problems, vision problems, altered consciousness, headache, vertigo, nausea, fatigue, dizziness, and abnormal sensations. Internal reliability was confirmed by arbitrarily dividing the dataset into two parts and repeating the analysis. The clusters mapped poorly onto traditional DCI categories (AGE, Type I DCS, Type II DCS), but more specifically onto the Perceived Severity Index (PSI). All three classification methods (DCI, Cluster, PSI) predicted complete relief of manifestations equally well. We conclude that cluster analysis is an objective method for classifying DCI manifestations independent of clinical judgment.

Venous Gas Emboli in Goats After Simulated Submarine Escape from 290 msw Breathing Air or Hyperoxic Gas

Escape from a disabled submarine has many inherent risks including the development of venous gas emboli (VGE). Breathing hyperoxic gas during rapid ascent from 2500 kPa (240 msw) reduces VGE; we investigated whether it would also be beneficial during an escape from 3000 kPa (290 msw), thought to be at the limit of human escape from a sunk sub. Adult castrated male or female goats (45-85 kg; N=35) underwent dry chamber compression to 3000 kPa in 28 s, then decompressed at a rate of 2.75 m x s(-1) while breathing either air or hyperoxic gas (60/40% O2/N2). Postsurfacing, precordial Doppler measurements were made using the Kisman Masurel (KM) scoring system; the animals were observed for signs of decompression illness (DCI) and/or oxygen toxicity. Six animals in the air group (N=19) and two in the hyperoxic group (N=10) suffered from severe pulmonary barotrauma on surfacing and were euthanized. No cases of DCI arose later than 5 min postsurfacing. Oxygen toxicity was not observed. Although initial bubble scores (median KM score 4) were the same in both groups, the time taken for the median KM score to reach 3 or less was significantly faster in the hyperoxic group (20 min vs. 120 min). Disappearance of VGE was faster in the hyperoxic group. Breathing hyperoxic gas during escape from 3000 kPa reduces the overall time with circulating VGE and, despite exposure to a maximum inspired partial pressure of oxygen of 1.8 MPa, symptoms of oxygen toxicity were not observed.

Acute decompression illness in UK tunnelling

Civil engineers have used compressed air to stabilise wet ground for over 150 years and continue to do so. But since 2001, compressed-air workers in the UK can no longer decompress on air alone—it now has to be done with the aid of oxygen. Despite one of the strictest regulatory environments in the world, Britain's construction industry recorded 428 cases of decompression illness between 1984 and 2002, leading to air-only decompression being banned. This paper provides an analysis of the UK's uniquely comprehensive database of compressed air exposure and decompression illness records which led to the ban. It provides a benchmark for assessing the effectiveness of oxygen decompression as well as informing other countries considering making the change.

Occupation as a risk factor in tunnelling decompression illness

The UK has an extensive collection of records of exposure to compressed air in tunnelling which are analysed periodically. The paper assesses occupation as a risk factor in tunnelling Decompression Illness (DCI) and is based on a batch of records covering around 120000 exposures derived from almost 2400 men on 34 contracts dating from the mid 1980s along with records of over 400 cases of acute DCI. For the study, the workforce was divided into four defined occupational categories covering production such as miners; skilled which included trades such as fitters and electricians; regular which covered staff and intermittent supervisory which included visitors. The incidence of DCI was determined together with the proportion of each category experiencing DCI. The study showed the extent to which shift workers experienced the majority of DCI events compared with their supervisory colleagues on a contract. The paper argues that bends rate - the commonly accepted measure of DCI incidence does not adequately identify the impact of DCI on shift workers from exposure to compressed air. (A) This paper was presented at Safety in the underground space - Proceedings of the ITA-AITES 2006 World Tunnel Congress and the 32nd ITA General Assembly, Seoul, Korea, 22-27 April 2006. For the covering abstract see ITRD E129148. Reprinted with permission from Elsevier.

Re-evaluation of the relationship between migraine and persistent foramen ovale and other right-to-left shunts

Right-to-left shunts (usually persistent foramen ovale) are responsible for a large proportion of cases of decompression illness [1,2]. Previously, we reported in Clinical Science [3] a review of the medical records of 200 consecutive individuals investigated for the cause of their decompression illness that showed that those with a large right-to-left shunt had a considerably increased prevalence of migraine with aura in daily life unconnected with diving, but not of migraine without aura. They also had an increased incidence of migraine aura after dives that liberate venous bubbles [3]. Transcatheter closure of persistent foramen ovale and atrial septal defects usually reduces the severity and frequency of attacks of migraine with aura [4]. Atrial shunts are dominantly inherited and this inheritance is closely associated with the inheritance of familial migraine with aura [5]. However, a significant role for right-to-left shunts in migraine aetiology does not accord with the generally accepted theories that migraine is a primary disorder of the brain [6]. Accordingly, we re-evaluated the observations reported previously in Clinical Science [3] in a further consecutive series. Data was collected from the next 200 consecutive divers (61 female) who attended our special clinic for investigation of decompression illness after the series we reported previously [3]. As part of clinical assessment, the history and the … Right-to-left shunts (usually persistent foramen ovale) are responsible for a large proportion of cases of decompression illness [1,2]. Previously, we reported in Clinical Science [3] a review of the medical records of 200 consecutive individuals investigated for the cause of their decompression illness that showed that those with a large right-to-left shunt had a considerably increased prevalence of migraine with aura in daily life unconnected with diving, but not of migraine without aura. They also had an increased incidence of migraine aura after dives that liberate venous bubbles [3]. Transcatheter closure of persistent foramen ovale and atrial septal defects usually reduces the severity and frequency of attacks of migraine with aura [4]. Atrial shunts are dominantly inherited and this inheritance is closely associated with the inheritance of familial migraine with aura [5]. However, a significant role for right-to-left shunts in migraine aetiology does not accord with the generally accepted theories that migraine is a primary disorder of the brain [6]. Accordingly, we re-evaluated the observations reported previously in Clinical Science [3] in a further consecutive series. Data was collected from the next 200 consecutive divers (61 female) who attended our special clinic for investigation of decompression illness after the series we reported previously [3]. As part of clinical assessment, the history and the …