Safety of hyperbaric oxygen therapy in mechanically ventilated patients

Background: To evaluate the epidemiology of patients who require mechanical ventilation during hyperbaric oxygen therapy. Materials and methods: One-hundred-fifty patients who required mechanical ventilation during hyperbaric oxygen therapy were prospectively studied during a 6-year period in a French university hyperbaric centre. We analysed the indication of hyperbaric oxygen therapy, agent used for sedation, presence of a chest tube, need for vasopressor agents and tolerance and appearance of side effects. Finally, we compared the outcomes of patients according to the presence or absence of acute respiratory distress syndrome (ARDS). Results: Eleven children and 139 adult patients were included (n = 150) in the study. In both populations, carbon monoxide poisoning (51%) and iatrogenic gas embolism (33%) were the two main causes of intubation and mechanical ventilation. The combination of midazolam and sufentanil was used in 85 (67%) patients. All of the patients were given a bolus of a neuromuscular blocker during the hyperbaric session, despite the presence of ARDS in 35 patients. Patient-ventilator asynchrony was the most frequent side effect in 6 (5%) patients and was often the consequence of suboptimal sedation. Mortality was higher in the group with ARDS (23%). Conclusions: Carbon monoxide poisoning and iatrogenic gas embolism are the two main diseases of the patients who required mechanical ventilation during hyperbaric oxygen therapy in this study. Mechanical ventilation is a safe method for patients during hyperbaric oxygen therapy. Sedation needs to be perfected to avoid patient-ventilator asynchrony.

Decompression sickness in urban divers in France

Background: Decompression sickness (DCS) can occur in SCUBA divers. DCS is treated with oxygen, preferably given under hyperbaric conditions. Although Paris (France) is located at a distance from the sea or lakes, some injured divers require hyperbaric oxygen treatment (HBOT) in this city, sometimes within a specific time frame. Thus, this study investigated the epidemiology and outcomes of such urban divers. Aim: We conducted an observational study of SCUBA divers admitted to the Raymond Poincaré Hyperbaric centre near Paris from 1993 to 2003. Materials and methods: We prospectively enrolled 69 consecutive SCUBA divers presenting DCS. Common risk factors were reported, especially aeroplane flight and training dives. Symptoms are very often atypical (63%) and onset time of symptoms is often too long (59% after 2 h) due to denial of symptoms. First aid is generally inadequate, with only 23% of victims receiving oxygen, fluid loading and aspirin together. HBOT was given for 42 (61%) patients although their examination results were considered as normal. Conclusions: Diving pits and diving travel agencies should do more to warn divers of the need for treatment with normobaric oxygen and hydration pending HBOT. Moreover, hyperbaric physicians should better clarify HBOT indications for both symptoms of late onset and atypical presentations

Hypotension post-intubation en médecine d'urgence (mise au point)

AIX-MARSEILLE2-BU Méd/Odontol. (130552103) / SudocSudocFranceF

Actualisation des connaissances sur le traitement médicamenteux de l'accident de décompression et proposition de stratégie de prise en charge (étude rétrospective des victimes d'accident de décompression traités au caisson de Garches entre 1993 et 2003)

PARIS5-BU Méd.Cochin (751142101) / SudocPARIS-BIUM (751062103) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocSudocFranceF

Functional reconstitution of Haemonchus contortus acetylcholine receptors in Xenopus oocytes provides mechanistic insights into levamisole resistance

International audienceBACKGROUND AND PURPOSE: The cholinergic agonist levamisole is widely used to treat parasitic nematode infestations. This anthelmintic drug paralyses worms by activating a class of levamisole-sensitive acetylcholine receptors (L-AChRs) expressed in nematode muscle cells. However, levamisole efficacy has been compromised by the emergence of drug-resistant parasites, especially in gastrointestinal nematodes such as Haemonchus contortus. We report here the first functional reconstitution and pharmacological characterization of H. contortus L-AChRs in a heterologous expression system. EXPERIMENTAL APPROACH: In the free-living nematode Caenorhabditis elegans, five AChR subunit and three ancillary protein genes are necessary in vivo and in vitro to synthesize L-AChRs. We have cloned the H. contortus orthologues of these genes and expressed them in Xenopus oocytes. We reconstituted two types of H. contortus L-AChRs with distinct pharmacologies by combining different receptor subunits. KEY RESULTS: The Hco-ACR-8 subunit plays a pivotal role in selective sensitivity to levamisole. As observed with C. elegans L-AChRs, expression of H. contortus receptors requires the ancillary proteins Hco-RIC-3, Hco-UNC-50 and Hco-UNC-74. Using this experimental system, we demonstrated that a truncated Hco-UNC-63 L-AChR subunit, which was specifically detected in a levamisole-resistant H. contortus isolate, but not in levamisole-sensitive strains, hampers the normal function of L-AChRs, when co-expressed with its full-length counterpart. CONCLUSIONS AND IMPLICATIONS: We provide the first functional evidence for a putative molecular mechanism involved in levamisole resistance in any parasitic nematode. This expression system will provide a means to analyse molecular polymorphisms associated with drug resistance at the electrophysiological level

The Easytube for airway management in prehospital emergency medicine

BACKGROUND: Securing the airway in emergency is among the key requirements of appropriate prehospital therapy. The Easytube (Ezt) is a relatively new device, which combines the advantages of both an infraglottic and supraglottic airway. AIMS: Our goal was to evaluate the effectiveness and the safety of use of Ezt by emergency physicians in case of difficult airway management in a prehospital setting with minimal training. METHODS: We performed a prospective multi-centre observational study of patients requiring airway management conducted in prehospital emergency medicine in France by 3 French mobile intensive care units from October 2007 to October 2008. RESULTS: Data were available for 239 patients who needed airway management. Two groups were individualized: the "easy airway management" group (225 patients; 94%) and the "difficult airway management" group (14 patients; 6%). All patients had a successful airway management. The Ezt was used in eight men and six women; mean age was 64 years. It was used for ventilation for a maximum of 150 min and the mean time was 65 min. It was positioned successfully at first attempt, except for two patients, one needed an adjustment because of an air leak, and in the other patient the Ezt was replaced due to complete obstruction of the Ezt during bronchial suction. CONCLUSION: The present study shows that emergency physicians in cases of difficult airway management can use the EzT safely and effectively with minimal training. Because of its very high success rate in ventilation, the possibility of blind intubation, the low failure rate after a short training period. It could be introduced in new guidelines to manage difficult airway in prehospital emergency

Place de l'aspirine dans le traitement médicamenteux de l'accident de désaturation

Objectif. Une grande partie du traitement médical adjuvant de l'accident de désaturation (ADD) repose sur l'administration d'aspirine, le plus précocement possible. Nous avons cherché sur quelles données s'appuyaient ces pratiques thérapeutiques et voulu connaître les habitudes des centres hyperbares français à ce sujet.
Méthodes. Enquête de pratique clinique de la prescription d'aspirine dans les centres hyperbares français dans le traitement médicamenteux adjuvant de l'ADD.
Résultats. La plupart des centres hyperbares français (77,5 %) prescrivent de l'aspirine aux plongeurs victimes d'ADD. Il existe pourtant peu de références justifiant cette pratique, souvent anciennes et trop rarement basées sur des preuves (Evidence-based Medecine).
Conclusion. Bien que largement utilisée en France, nous manquons de données scientifiques irréfutables pour justifier de l'utilisation de l'aspirine dans la prise en charge de l'ADD