Hyperbaric oxygenation improve red blood cell deformability in patients with acute or chronic inflammation.

INTRODUCTION: Red blood cells (RBC) are one of the key elements of the microcirculation. Their ability to pass through capillaries and to deliver oxygen to cells is due to their large degree of deformability linked to the characteristics of the RBC membrane. Alterations in RBC deformability as a result of membrane damage, linked in part to increased synthesis of reactive oxygen species (ROS), can be observed in several diseases, such as sepsis, and may contribute to the altered microcirculation observed in these pathologies. Hyperbaric oxygen therapy (HBOT), with inhalation of 100 % oxygen, has been proposed in several acute or chronic pathologies, including carbon monoxide poisoning. OBJECTIVE: We investigated the effects of HBOT on oxidative stress from ROS produced by myeloperoxidase (MPO) and on RBC deformability in patients with acute or chronic inflammation (n = 10), in patients with acute carbon monoxide poisoning (n = 10), and in healthy volunteers (n = 10). METHODS: RBC deformability was evaluated before and after HBOT in the various populations using the ektacytometry technique (Laser-assisted Optical Rotational Red Cell Analyzer - LORRCA). Deformability was determined by the elongation index (EI) in relation to the shear stress (SS) over a range of 0.3 to 50 Pa. Oxidative stress was estimated through changes in proteins (chlorotyrosine and homocitrulline) induced by MPO activity measured by liquid chromatography-tandem mass spectrometry analysis. RESULTS: Before HBOT, EI was significantly lower in patients with acute or chronic inflammation than in healthy volunteers and patients with acute carbon monoxide poisoning for the majority of SS values studied. After one session of HBOT, the EI was significantly higher than before HBOT for SS values of 1.93 Pa or higher in patients with acute or chronic inflammation. This effect remains constant after 10 sessions. There were no differences before and after HBOT in protein or amino acid oxidation due to ROS generation mediated by MPO in the three populations. CONCLUSIONS: Our results confirm altered RBC deformability in patients with acute and chronic conditions associated with an underlying inflammatory process. HBOT improves deformability only after one session and therefore may improve microcirculation in this population. According to our results, this improvement does not seem mediated by the ROS pathway via MPO. These results need to be confirmed in a larger population.

Are seminal vesicles a potential pitfall during pelvic exploration using point-of-care ultrasound (POCUS)?

BACKGROUND: Trauma is a major cause of death among the working population. Many countries have now adopted a structured approach to trauma management in which ultrasound is used as a primary evaluation tool. While its use has direct therapeutic benefits, many artifacts and pitfalls are inherent to the technique. Knowledge of the most frequently encountered pitfalls in practice could thus help reduce the risk of error and lead to more accurate trauma assessments. OBJECTIVE: This study evaluates a potential pitfall caused by seminal vesicles during focused assessment with sonography for trauma examinations of the male pelvis performed by an emergency physician with experience in point-of-care ultrasound. METHODS: We took five static and five dynamic (3-s loops) transverse ultrasound images of the pelvis in five healthy males. The images and videos were then incorporated into an online survey and emailed through the World Interactive Network Focused On Critical UltraSound (WINFOCUS) in France and the Ultrasound and Emergency Medicine (UEM) Organization in Belgium. A questionnaire asked anonymous participants to assess the presence of free fluid in the static and dynamic images and to share information about their training and experience in point-of-care ultrasound. To validate the static and dynamic images, the survey was sent to three external radiologists for independent verification. RESULTS: A total of 191 individuals responded fully or partially to the survey, 114 of whom completed it. Among the 114 participants who completed the survey, the misinterpretation rate was 0.55 (95CI 0.51-0.60) for all static and dynamic ultrasound transverse pelvic views. The misinterpretation rate was 0.61 (95CI 0.55-0.66) and 0.50 (95CI 0.45-0.55) for static and dynamic ultrasound transverse pelvic views, respectively. The three external radiologists answered the questionnaire correctly without misinterpreting the survey ultrasound views. CONCLUSIONS: Seminal vesicles are a potential pitfall when interpreting transverse ultrasound images of the male pelvis in the context of point-of-care ultrasound.