Abstract This study assessed the relationship between altered cardiac function and the development interstitial pulmonary edema in SCUBA divers. Fifteen healthy males performed a 30-min SCUBA dive in ...open sea. They were instructed to fin for 30 min and were wearing wet suits. Before and immediately after immersion, cardiac indices and extravascular lung water were measured using echocardiography and lung ultrasound respectively. The mean ultrasound lung comet score rose from 0 to 4.6 ± 3.4. The diameter of the inferior caval vein increased by 47 ± 5.2%, systolic pulmonary artery pressure increased by 105 ± 8.6%, left atrial volume increased by 18.0 ± 3.3% and left ventricle end-diastolic volume increased by 10 ± 2.4% suggesting both right and left ventricular filling pressures were elevated. Doppler studies showed an increased mitral E peak (+2.5 ± 0.3%) and E/A ratio (+22.5 ± 3.4%) with a decreased mitral A peak (-16.4 ± 2.7%), E peak deceleration time (-14.5 ± 2.4%) consistent with rapid early left ventricular filling but without a change in left ventricular stroke volume. There was an increase in right/left ventricle diameter ratio (+33.6 ± 4.8%) suggesting a relative increase in right sided heart output compared to the left. Furthermore, the lung comet score correlated significantly with inferior caval vein diameter, systolic pulmonary artery pressure, right/left ventricle diameter ratio and E-wave deceleration time. In conclusion, the altered right/left heart stroke volume balance could play an essential role in the development of immersion pulmonary edema. Our findings have important implications for the pathogenesis of cardiogenic pulmonary edema.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Abstract Purpose This study was designed to determine the recompression strategy and the potential risk factors associated with the development of severe diving-related spinal cord decompression ...sickness (DCS). Material and Methods Sixty-three injured recreational divers (52 men and 11 women; 46 ± 12 years) presenting with symptoms of spinal involvement were retrospectively included. Diving information, symptom latency after dive completion, and time interval between symptom onset and hyperbaric treatment were studied. The severity of spinal cord DCS was rated numerically for both the acute event and 1-month later. Initial recompression treatment at 2.8 atmosphere absolute (ATA) with 100% oxygen breathing or deeper recompression at 4 atmosphere absolute with nitrogen-oxygen or helium-oxygen breathing mixture was also noted. Results Twenty-one divers (33%) had incomplete resolution after 1 month. The clinical severity at presentation was the only independent predictor of poor outcome (odd ratio, 2.68; P < .033). Time to treatment did not influence the recovery with a similar median delay (3 hours) between the divers with or without long-term sequelae. Choice of recompression procedure was not also a determinant factor for treatment outcome. Conclusion The initial clinical course before treatment is a major prognostic factor of spinal cord DCS. Delay to recompression less than 3 hours and use of deep treatment tables did not improve outcome in DCS divers.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Immersion pulmonary edema in scuba divers is a rare disorder that tends to recur and can be potentially fatal, even in the absence of underlying cardiac disease. Anecdotal cases of reversible ...myocardial dysfunction have been described in this setting, but little is known of its pathogenesis. The purpose of the present study was to determine the clinical outcomes and the determinants associated with this condition. The data from 54 consecutive divers admitted for acute immersion pulmonary edema during a 5.5-year period were retrospectively studied. A diagnosis of myocardial dysfunction was established by the presence of elevated cardiac troponin T levels, coupled with electrocardiographic changes and/or wall motion abnormalities on the echocardiogram. The demographic, clinical, biologic, and diving characteristics were tested as potential predictors of this disorder. All the patients had complete resolution of symptoms within 72 hours, but 3 required intensive ventilation or hemodynamic support at admission. Reversible myocardial dysfunction was observed in 28% and was associated more with age >50 years (odds ratio OR 5.5, 95% confidence interval CI 1.5 to 21, p = 0.013), hypertension (OR 8.2, 95% CI 2.1 to 32, p = 0.002), diabetes (OR 22.1, 95% CI 1.1 to 458; p = 0.002), and release of natriuretic peptides (OR 9.1, 95% CI 2.4 to 35, p = 0.001). Follow-up investigations at 1 month were obtained for 49 patients and revealed a significant number of patients with occult hypertension. In conclusion, reversible myocardial dysfunction is not uncommon in divers with immersion pulmonary edema. The short-term overall prognosis is not adversely altered, but severe heart failure with a fatal outcome is unpredictable. Close monitoring of older divers with latent cardiovascular risk factors is warranted.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Introduction
Spinal cord decompression sickness (scDCS) unfortunately has a high rate of long-term sequelae. The purpose of this study was to determine the best therapeutic management in a hyperbaric ...center and, in particular, the influence of hyperbaric treatment performed according to tables at 4 atm (Comex 30) or 2.8 atm abs (USNT5 or T6 equivalent).
Methods
This was a retrospective study that included scDCS with objective sensory or motor deficit affecting the limbs and/or sphincter impairment seen at a single hyperbaric center from 2010 to 2020. Information on dive, time to recompression, and in-hospital management (hyperbaric and medical treatments such as lidocaine) were analyzed as predictor variables, as well as initial clinical severity and clinical deterioration in the first 24 h after initial recompression. The primary endpoint was the presence or absence of sequelae at discharge as assessed by the modified Japanese Orthopaedic Association score.
Results
102 divers (52 ± 16 years, 20 female) were included. In multivariate analysis, high initial clinical severity, deterioration in the first 24 h, and recompression tables at 4 atm versus 2.8 atm abs for both initial and additional recompression were associated with incomplete neurological recovery. Analysis of covariance comparing the effect of initial tables at 2.8 versus 4 atm abs as a function of initial clinical severity showed a significantly lower level of sequelae with tables at 2.8 atm. In studying correlations between exposure times to maximum or cumulative O2 dose and the degree of sequelae, the optimal initial treatment appears to be a balance between administration of a high partial pressure of O2 (2.8 atm) and a limited exposure duration that does not result in pulmonary oxygen toxicity. Further analysis suggests that additional tables in the first 24–48 h at 2.8 atm abs with a Heliox mixture may be beneficial, while the use of lidocaine does not appear to be relevant.
Conclusion
Our study shows that the risk of sequelae is related not only to initial severity but also to clinical deterioration in the first 24 h, suggesting the activation of biological cascades that can be mitigated by well-adapted initial and complementary hyperbaric treatment.
Circulating mitochondrial DNA (mtDNA) is receiving increasing attention as a danger-associated molecular pattern in conditions such as autoimmunity or trauma. In the context of decompression sickness ...(DCS), the course of which is sometimes erratic, we hypothesize that mtDNA plays a not insignificant role particularly in neurological type accidents. This study is based on the comparison of circulating mtDNA levels in humans presenting with various types of diving accidents, and punctured upon their admission at the hyperbaric facility. One hundred and fourteen volunteers took part in the study. According to the clinical criteria there were 12 Cerebro DCS, 57 Medullary DCS, 15 Vestibular DCS, 8 Ctrl+ (accident-free divers), and 22 Ctrl- (non-divers). This work demonstrates that accident-free divers have less mtDNA than non-divers, which leads to the assumption that hyperbaric exposure degrades the mtDNA. mtDNA levels are on average greater in divers with DCS compared with accident-free divers. On another hand, the amount of double strand DNA (dsDNA) is neither significantly different between controls, nor between the different DCS types. Initially the increase in circulating oligonucleotides was attributed to the destruction of cells by bubble abrasion following necrotic phenomena. If there really is a significant difference between the Medullary DCS and the Ctrl-, this difference is not significant between these same DCS and the Ctrl+. This refutes the idea of massive degassing and suggests the need for new research in order to verify that oxidative stress could be a key element without necessarily being sufficient for the occurrence of a neurological type of accident.
Background
Immersion pulmonary edema is potentially a catastrophic condition; however, the pathophysiological mechanisms are ill-defined. This study assessed the individual and combined effects of ...exertion and negative pressure breathing on the cardiovascular system during the development of pulmonary edema in SCUBA divers.
Methods
Sixteen male professional SCUBA divers performed four SCUBA dives in a freshwater pool at 1 m depth while breathing air at either a positive or negative pressure both at rest or with exercise. Echocardiography and lung ultrasound were used to assess the cardiovascular changes and lung comet score (a measure of interstitial pulmonary edema).
Results
The ultrasound lung comet score was 0 following both the dives at rest regardless of breathing pressure. Following exercise, the mean comet score rose to 4.2 with positive pressure breathing and increased to 15.1 with negative pressure breathing. The development of interstitial pulmonary edema was significantly related to inferior vena cava diameter, right atrial area, tricuspid annular plane systolic excursion, right ventricular fractional area change, and pulmonary artery pressure. Exercise combined with negative pressure breathing induced the greatest changes in these cardiovascular indices and lung comet score.
Conclusions
A diver using negative pressure breathing while exercising is at greatest risk of developing interstitial pulmonary edema. The development of immersion pulmonary edema is closely related to hemodynamic changes in the right but not the left ventricle. Our findings have important implications for divers and understanding the mechanisms of pulmonary edema in other clinical settings.
Vascular bubble formation after decompression contributes to endothelial injuries which form the basis for the development of decompression sickness (DCS). Nitric oxide (NO) is a powerful vasodilator ...that contributes to vessel homeostasis. It has been shown that NO-releasing agent may reduce bubble formation and prevent serious decompression sickness. The use of sildenafil, a well-known, phosphodiesterase-5 blocker, which act by potentiating the vasodilatory effect on smooth muscle relaxation, has never been studied in DCS. The purpose of the present study was to evaluate the clinical effects of sildenafil pre-treatment on DCS in a rat model. 67 rats were subjected to a simulated dive at 90 msw for 45 min before staged decompression. The experimental group received 10 mg/kg of sildenafil one hour before exposure (n = 35) while controls were not treated (n = 32). Clinical assessment took place over a period of 30 min after surfacing. At the end, blood samples were collected for blood cells counts and the level of circulating bubbles in the right cavities was quantified. There were significantly more manifestations of DCS in the sildenafil group than in the controls (34.3% vs 6.25%, respectively, p = 0.012). Platelet count was more reduced in treated rats than in controls (-21.7% vs -7%, respectively, p = 0.029), whereas bubble grades did not differ between groups. We concluded that pre-treatment with sildenafil promotes the onset and severity of neurological DCS. When considering the use of phosphodiesterase-5 blockers in the context of diving, careful discussion with physician should be recommended.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract Background Post-decompression shock with plasma volume deficit is a very rare event that has been observed under extreme conditions of hypobaric and hyperbaric exposure in aviators and ...professional divers. Case Report We report a case of severe hypovolemic shock due to extravasation of plasma in a recreational scuba diver presenting with inner ear decompression sickness. Impaired endothelial function can lead to capillary leak with hemoconcentration and hypotension in severe cases. This report suggests that decompression-induced circulating bubbles may have triggered the endothelial damage, activating the classic inflammatory pathway of increased vascular permeability. Conclusion This observation highlights the need for an accurate diagnosis of this potentially life-threatening condition at the initial presentation in the Emergency Department after a diving-related injury. An elevated hematocrit in a diver should raise the suspicion for the potential development of capillary leak syndrome requiring specific treatment using albumin infusion as primary fluid replacement.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Inner ear decompression sickness (IEDCS) in scuba divers is increasingly observed, but epidemiological data are limited to small case series and the pathogenesis remains elusive. We report our ...experience over a 13-year period. We also thought to demonstrate that the development of this injury is mainly attributed to a mechanism of vascular origin. Diving information, clinical data, presence of circulatory right-to-left shunt (RLS), and laboratory investigations of 115 recreational divers were retrospectively analyzed. A follow-up study at 3 months was possible with the last 50 consecutive cases. IEDCS (99 males, 44 ± 11 years) represented 24 % of all the patients treated. The median delay of onset of symptoms after surfacing was 20 min. Violation of decompression procedure was recorded in 3 % while repetitive dives were observed in 33 %. The median time to hyperbaric treatment was 180 min. Pure vestibular disorders were observed in 76.5 %, cochlear deficit in 6 % and combination of symptoms in 17.5 %. Additional skin and neurological disorders were reported in 15 % of cases. In 77 %, a large RLS was detected with a preponderant right-sided lateralization of IEDCS (80 %,
P
< 0.001). Incomplete recovery was found in 68 % of the followed patients. Time to recompression did not seem to influence the clinical outcome. IEDCS is a common presentation of decompression sickness following an uneventful scuba dive, but the therapeutic response remains poor. The high prevalence of RLS combined with a right-sided predominance of inner ear dysfunction suggests a preferential mechanism of paradoxical arterial gas emboli through a vascular anatomical selectivity.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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