The effect of general anaesthesia and neuromuscular blockade on Eustachian tube compliance: a prospective study.

OBJECTIVE: The most common complications of hyperbaric oxygen treatment (HBOT) are related to pressure changes on gas-containing cavities. Therefore, inability to auto-inflate the middle ear may result in transient or permanent hearing loss. However, it seems that middle ear barotrauma (MEBt) does not develop more often in mechanically ventilated patients than in ambulatory patients. This might be explained by deep sedation of these patients. Therefore, the aim of this study was to determine whether anaesthesia and/or neuromuscular blockade can influence Eustachian tube (ET) function. METHODS: Forty patients who were undergoing surgery under general anaesthesia were enrolled in this prospective study. ET function was evaluated by tympanography performed three times: before induction of general anaesthesia (baseline), after induction with sufentanyl/propofol and after full blockade was achieved with a long-acting neuromuscular blocking agent. RESULTS: There were no differences in ear volume (P = 0.19) and ear pressure (P = 0.07). There was a significant variation in compliance on tympanography after the induction of general anaesthesia (P = 0.009). Compared to the baseline, this variation was characterized by an increase after induction of anaesthesia (24 ± 7.13%, P 〈 0.01) and neuromuscular blockade (23 ± 8.9%, P 〈 0.05). The difference between after induction and after neuromuscular blockade was not statistically significant (P = 0.13). DISCUSSION: The findings of this trial suggest that the administration of hypnotic drugs associated with opioids improves ET compliance. Therefore it may have favourable prophylactic effects on MEBt in ventilated intensive care unit patients scheduled for HBOT.

Occupational accidents among attendants inside hyperbaric chambers in France.

INTRODUCTION: The purpose of the study was to assess the number of accidents among staff employed in the operation of hyperbaric chambers in France. MATERIALS AND METHODS: A retrospective study using a questionnaire was carried out on occupational accidents in France between 2005 and 2011. RESULTS: 12 (46%) centres participated in the study, representing 73 subjects. The mean age was 43.5 years (SD=9.73). They had worked in hyperbaric chambers for 9.8 years on average (SD=7.7). The average number of hyperbaric sessions was 198.3 per subject (SD=174.25), for a total of 8.072 hyperbaric sessions; 27% of the subjects reported that they had at least one accident during the study period. In all, 30 accidents were reported: 3 blood exposures, 4 accidents related to patient handling, 20 hyperbaric accidents; 3 other accidents. Of the hyperbaric accidents, 2 (10%) involved decompression sicknesses with cutaneous symptoms, 3 (15%) decompression illness (DCI), 14 (70%) ear traumatisms, 1 (5%) dental accident. The incidences were 372 per 100,000 sessions in hyperbaric chambers (SHC) for all accidents, 248 per 100,000 SHC for hyperbaric accidents and 173 per 100,000 SHC for ENT barotraumas. CONCLUSION: The accidents involving staff operating hyperbaric chambers were mainly ear traumatisms..

Intracerebral hemorrhage related to systemic gas embolism during hysteroscopy.

Iatrogenic gas embolism is a rare but serious problem that has been documented in almost all medical specialties including gynecology. We present a 49-year-old woman undergoing operative hysteroscopy and myomectomy, who sustained sudden hypotension and decrease in the end-tidal carbon dioxid levels during the procedure. Systemic gas embolism was confirmed by echocardiographic evidence of bubbles in both right and left cardiac cavities and a rise of troponin. Hyperbaric oxygen was rapidly administered in addition to maintenance of vital functions and anti-thrombotic prevention with calciparin. A right hemiparesis was apparent after recovery from general anesthesia. Brain-computed tomography and magnetic resonnance imaging, performed on Days 3 and 2 respectively, showed a left fronto-parietal hematoma surrounded by edema. Having ruled out risk factors for a primary ischemic or hemorrhagic stroke, we concluded that hemorragic transformation of the ischemic cerebral lesion caused by gas embolism was responsible for the observed intraparenchymal hematoma. As far as we know, this is the first report relating cerebral gas embolism with an intracerebral hemorrhage. It provides an argument against anticoagulant therapy during the early stages of gas embolism care.