Search

Background Decompression sickness (DCS) is a well-known risk associated with scuba diving, particularly in people with right-to-left shunt, such as patent foramen oval (PFO). Herein, we present a unique case of late PFO permeabilization after closure. Case summary A 26-year-old male diver was diagnosed with DCS following a dive at 36 m. He underwent PFO closure with a STARFLEX® prosthesis. Ten years later, the patient was presented with recurrent manifestations suggestive of DCS. The performed diagnostic work-up detects a permeabilization of the implanted prosthesis, and he was treated with a conservative approach. Discussion This case highlights the challenges in the management of PFO in divers and raises concerns about the long-term efficiency of PFO closure and the impact of diving-related factors on prosthesis patency. [ABSTRACT FROM AUTHOR]

Ischaemia-modified albumin (IMA) is a marker of the release of reactive oxygen species (ROS) during hypoxaemia. In elite divers, breath-hold induces ROS production. Our aim was to evaluate the kinetics of IMA serum levels during apnea. Twenty breath-hold divers were instructed to perform a submaximal static breath-hold. Twenty non-diver subjects served as controls. Blood samples were collected at rest, every minute, at the end of breath-hold, and 10 min after recovery. The IMA level increased after 1 min of breath-hold (p < 0.003) and remained high until recovery. Divers were separated into 2 groups: subjects who held their breath for less than 4 min (G-4) and those who held it for more than 4 min (G+4). After 3 min of apnoea, the increase of IMA was higher in the G-4 group than in the G+4 group (p < 0.008). However, at the end of apnoea, the IMA level did not differ between groups. If IMA level was globally correlated with the apnoea duration, it is interesting to note that the higher IMA level was not found in the best divers. Similarly, if arterial blood oxygen saturation (Sp[O.sub.2]) was globally inversely correlated with apnoea duration, the lowest Sp[O.sub.2] at the end of breath-hold was not found in the divers that performed the best apnoea. We concluded that these divers save their oxygen. The IMA level provides a useful measure of resistance to hypoxaemia. Key words: breath-hold, hypoxia, free-divers, ischaemia-modified albumin. L'albumine modifiee par l'ischemie (AMI) est un marqueur de la liberation d'especes reactives d'oxygene (ERO) lors de l'hypoxemie. Chez les plongeurs d'elite, l'apnee induit la production d'ERO. Le but des auteurs etait d'evaluer la cinetique des niveaux seriques d'AMI durant l'apnee. Vingt plongeurs libres ont recu comme consigne de realiser une apnee sousmaximale statique. Vingt sujets non plongeurs ont servi de controles. Des echantillons sanguins ont ete recueillis au repos, a chaque minute, a la fin de la periode d'apnee, et 10 min apres la periode de recuperation. Le niveau d'AMI augmentait apres une minute d'apnee (p < 0,003) et demeurait eleve jusqu'a la periode de recuperation. Les plongeurs ont ete repartis en 2 groupes, ceux qui maintenaient une apnee pendant moins de 4 min (G-4) et ceux qui la maintenaient plus de 4 min (G+4). Apres 3 min d'apnee, l'accroissement d'AMI etait plus eleve chez le groupe G-4 comparativement au groupe G+4 (p < 0,008). Cependant, a la fin de l'apnee, le niveau d'AMI etait le meme chez les deux groupes. Si le niveau d'AMI etait globalement en correlation avec la duree de l'apnee, il etait interessant d'observer que le niveau le plus eleve d'AMI ne se trouvait pas chez les meilleurs plongeurs. De la meme facon, si le Sp[O.sub.2] etait en correlation inverse avec la duree de l'apnee, le niveau plus faible de Sp[O.sub.2] a la fin de la periode d'apnee ne se trouvait pas chez les plongeurs les plus performants en terme de duree. Les auteurs concluent que ces plongeurs economisent leur oxygene. Le niveau d'AMI fournit une mesure utile de resistance a l'hypoxemie. [Traduit par la Redaction] Mots-cles : apnee, hypoxie, plongeurs libres, albumine modifiee par l'ischemie., Introduction Ischaemia-modified albumin (IMA) is a marker of tissue ischaemia (Bar-Or et al. 2001). IMA is produced by the release from ischaemic tissue of free radicals that modify the N [...]

Introduction: Portal venous gas from a diving injury is an infrequent finding and only a few cases are described. We report a case of severe decompression sickness (DCS) associated with a massive amount of gas in the portal and mesenteric veins. Case report: A 49-year-old man suffered from DCS after two deep dives on the same day. He presented with cutaneous, neurological and pulmonary symptoms associated with hypoxaemia. He had no abdominal pain. A computed tomography (CT) scan showed large quantities of hepatic and portal venous gas and excluded other explanations for its presence. All symptoms disappeared with hyperbaric oxygen therapy and there were no further complications. Discussion and conclusion: The role of portal venous gas in DCS is not obvious. Isolated portal venous gas seems to cause no obvious harm. Medical imaging should be considered for differential diagnosis and to prevent some complications, especially in divers presenting with abdominal pain. [ABSTRACT FROM AUTHOR]

BACKGROUND: Previous studies on ventilators used for air transport showed significant effects of altitude, in particular with regard to accuracy of the tidal volume (VT) and breathing frequency. The aim of the study was to evaluate transport ventilators under hypobaric conditions. METHODS: We conducted a bench study of 6 transport ventilators in a Comex hypobaric chamber to simulate mild altitude (1,500 m [4,920 feet] and 2,500 m [8,200 feet]). The ventilators were connected to a test lung to evaluate their accuracy: (1) to deliver a set VT under normal resistance and compliance conditions at FIO2 = 0.6 and 1, (2) to establish a set PEEP (0, 5, 10, and 15 cm H2O), and (3) to establish a set inspiratory pressure in pressure controlled mode, (4) at a FIO2 setting, and (5) and at a frequency setting. RESULTS: Four ventilators kept an average relative error in VT of < 10% without effect of altitude. The Medumat ventilator was affected by the altitude only at FIO2 = 1. The Osiris 3 ventilator had > 40% error even at 1,500 m. We found no change in frequency as a function of altitude for any ventilators studied. No clinically important differences were found between all altitudes with the PEEP or inspiratory pressure setting. Although FIO2 was affected by altitude, the average error did not exceed 11%, and it is unclear whether this fact is an experimental artifact. CONCLUSIONS: We have shown that most of the new transport ventilators tested require no setting adjustment at moderate altitude and are as safe at altitude as at sea level under normal respiratory conditions. Older technologies still deliver more volume with altitude in volumetric mode. [ABSTRACT FROM AUTHOR]

Introduction: Hyperbaric oxygen (HBO2) therapy is the use of oxygen or gas mixtures at a pressure above atmospheric pressure for therapeutic purposes. This treatment is used in numerous pathological processes. Its main side effect is middle ear barotrauma (MEB), which represents a great concern for iatrogenic HBO2 therapy. The aim of this work is to describe this adverse event in order to highlight clinical elements that can contribute to its prevention and management., Methods: We conducted a five-year retrospective study from January 2013 to December 2017, where 2,610 patients were selected, in the Hyperbaric Medicine Centre, Sainte- Marguerite Hospital of Marseille, France., Results: 262 patients experienced MEB after HBO2, representing a prevalence of 10.04% and incidence of 0.587%. Their average age was 55 ± 19 years. Women were more affected than men. We have not highlighted a seasonality to this condition. Risk factors were: age older than 55 years, female gender, ear, nose and throat history (cancer, radiotherapy, infections or allergies, malformations or benign tumors), general history (smoking, obstructive breathing disorders, thyroid disorders and obesity), HBO2-approved indications of sudden deafness and delayed wound healing, and altered tympanic mobility on initial examination. Although the benign stages of Haines-Harris classification were the most encountered in our study, MEB was responsible for premature discontinuation of HBO2., Conclusion: MEB is a common condition responsible for many premature discontinuations of HBO2. Its origin is multifactorial, associating non-modifiable and modifiable factors. Better management of this affection will further contribute to making HBO2 a low-risk treatment., Competing Interests: The authors of this paper declare no conflicts of interest exist with this submission., (Copyright© Undersea and Hyperbaric Medical Society.)

OBJECTIVE. The purpose of our study was to define the postmortem CT semiology of gas collections linked to putrefaction, postmortem "off-gassing," and decompression illness after fatal diving accidents and to establish postmortem CT diagnostic criteria to distinguish the different causes of death in diving. SUBJECTS AND METHODS. A 4-year prospective study was conducted including cases of death during diving. A hyperbaric physician analyzed the circumstances of death and the dive profile, and an autopsy was performed. Subjects were divided into three groups according to the analysis from their dive profile: decompression illness, death after decompression dive without decompression illness, and death after nondecompression dive without decompression illness. Full-body postmortem CT was performed before autopsy. RESULTS. The presence of intraarterial gas associated with death by decompression illness had a negative predictive value (NPV) of 100%, but the positive predictive value (PPV) was only 54% because of postmortem off-gassing. The PPV reached 70% when considering pneumatization of the supraaortic trunks. Pneumothorax, subcutaneous emphysema, and intraarterial gas, all of which are classic criteria for decompression illness diagnosis, are not specific for decompression illness. CONCLUSION. This study is the first to show that pneumothorax, subcutaneous emphysema, and intraarterial gas, all of which are classic criteria for decompression illness diagnosis, are not specific for decompression illness. Complete pneumatization of supraaortic trunks is the best postmortem CT criteria to detect a fatal decompression illness when CT is performed within 24 hours after death.

Background: Middle-ear barotrauma (MEB) is one of the most common side effects of hyperbaric oxygen therapy (HBO2). The incidence of MEB has been shown to vary between treatment centers and patients. This study was aimed to determine which patients are at high risk of MEB., Materials and Methods: Prospective study including all the patients treated in a multiplace HBO2 chamber between January and December 2005. Scoring of MEB before and after HBO2 by otoscopy was performed using the Haines and Harris classification., Results: We included 130 patients: 53 Males, 37.5 +/- 20.5 years old; 76% were treated for CO poisoning, 11% for iatrogenic gas embolism, 12% for decompression sickness and 4% for necrotizing soft tissue infection. 13% were intubated. MEB occurred in 13.6% of the patients (12.4% of the conscious and 24.4% of the intubated patients, p = 0.26). Risk factors for MEB were: repetitive treatments and difficulties with pressure equalization. There was no influence of age, sex or mechanical ventilation on the occurrence of MEB., Conclusions: MEB induced by HBO2 occurred in 13.6% of the patients. There is no difference in incidence when comparing intubated and non-intubated patients. In non-comatose patients, difficulties with equalizing pressure were predictive of MEB.