Neurological outcome of cardiac arrest patients in mountain areas: An analysis of the Northern French Alps Emergency Network.

BACKGROUND: Mountainous areas pose a challenge for the out-of-hospital cardiac arrest (OHCA) chain of survival. Survival rates for OHCAs in mountainous areas may differ depending on the location. Increased survival has been observed compared to standard location when OHCA occurred on ski slopes. Limited data is available about OHCA in other mountainous areas. The objective was to compare the survival rates with a good neurological outcome of OHCAs occurring on ski slopes (On-S) and off the ski slopes (OffS) compared to other locations (OL). METHODS: Analysis of prospectively collected data from the cardiac arrest registry of the Northern French Alps Emergency Network (RENAU) from 2015 to 2021. The RENAU corresponding to an Emergency Medicine Network between all Emergency Medical Services and hospitals of 3 counties (Isère, Savoie, Haute-Savoie). The primary outcome was survival at 30 days with a Cerebral Performance Category scale (CPC) of 1 or 2 (1: Good Cerebral Performance, 2: Moderate Cerebral Disability). RESULTS: A total of 9589 OHCAs were included: 213 in the On-S group, 141 in the Off-S group, and 9235 in the OL group. Cardiac etiology was more common in On-S conditions (On-S: 68.9% vs OffS: 51.1% vs OL: 66.7%, p < 0.001), while Off-S cardiac arrests were more often due to traumatic circumstances (OffS: 39.7% vs On-S: 21.7% vs OL: 7.7%, p < 0.001). Automated external defibrillator (AED) use before rescuers' arrival was lower in the Off-S group than in the other two groups (On-S: 15.2% vs OL: 4.5% vs OffS: 3.7%; p < 0.002). The first AED shock was longer in the Off-S group (median time in minutes: OffS: 22.0 (9.5-35.5) vs On-S: 10.0 (3.0-19.5) vs OL: 16.0 (11.0-27.0), p = 0.03). In multivariate analysis, on-slope OHCA remained a positive factor for 30-day survival with a CPC score of 1 or 2 with a 1.96 adjusted odds ratio (95% confidence interval (CI), 1.02-3.75, p = 0.04), whereas off-slope OHCA had an 0.88 adjusted odds ratio (95% CI, 0.28-2.72, p = 0.82). CONCLUSIONS: OHCAs in ski-slopes conditions were associated with an improvement in neurological outcomes at 30 days, whereas off-slopes OHCAs were not. Ski-slopes rescue patrols are efficient in improving outcomes.

Multidimensional Analysis of the Adult Human Heart in Health and Disease using Hierarchical Phase-Contrast Tomography (HiP-CT).

Cardiovascular diseases (CVDs) are a leading cause of death worldwide. Current clinical imaging modalities provide resolution adequate for diagnosis but are unable to provide detail of structural changes in the heart, across length-scales, necessary for understanding underlying pathophysiology of disease. Hierarchical Phase-Contrast Tomography (HiP-CT), using new (4th) generation synchrotron sources, potentially overcomes this limitation, allowing micron resolution imaging of intact adult organs with unprecedented detail. In this proof of principle study (n=2), we show the utility of HiP-CT to image whole adult human hearts ex-vivo: one 'control' without known cardiac disease and one with multiple known cardiopulmonary pathologies. The resulting multiscale imaging was able to demonstrate exemplars of anatomy in each cardiac segment along with novel findings in the cardiac conduction system, from gross (20 um/voxel) to cellular scale (2.2 um/voxel), non-destructively, thereby bridging the gap between macroscopic and microscopic investigations. We propose that the technique represents a significant step in virtual autopsy methods for studying structural heart disease, facilitating research into abnormalities across scales and age-groups. It opens up possibilities for understanding and treating disease; and provides a cardiac 'blueprint' with potential for in-silico simulation, device design, virtual surgical training, and bioengineered heart in the future.

Variations of the obturator nerve and implications in obturator nerve entrapment treatment: an anatomical study.

INTRODUCTION: Obturator nerve entrapment or idiopathic obturator neuralgia is an unfamiliar pathology for many physicians which can lead to diagnostic errancy. This study aims to identify the potential compression areas of the obturator nerve to improve therapeutic management. MATERIAL AND METHODS: 18 anatomical dissections of lower limbs from 9 anatomical cadavers were performed. Endopelvic and exopelvic surgical approaches were utilized to study the anatomical variations of the nerve and to identify areas of entrapment. RESULTS: On 7 limbs, the posterior branch of the obturator nerve passed through the external obturator muscle. A fascia between the adductor brevis and longus muscles was present in 9 of the 18 limbs. The anterior branch of the obturator nerve was highly adherent to the fascia in 6 cases. In 3 limbs, the medial femoral circumflex artery was in close connection with the posterior branch of the nerve. CONCLUSION: Idiopathic obturator neuropathy remains a difficult diagnosis. Our cadaveric study did not allow us to formally identify one or more potential anatomical entrapment zones. However, it allowed the identification of zones at risk. A clinical study with staged analgesic blocks would be necessary to identify an anatomical area of compression and would allow targeted surgical neurolysis.

Preparation of large biological samples for high-resolution, hierarchical, synchrotron phase-contrast tomography with multimodal imaging compatibility.

Imaging across different scales is essential for understanding healthy organ morphology and pathophysiological changes. The macro- and microscale three-dimensional morphology of large samples, including intact human organs, is possible with X-ray microtomography (using laboratory or synchrotron sources). Preparation of large samples for high-resolution imaging, however, is challenging due to limitations such as sample shrinkage, insufficient contrast, movement of the sample and bubble formation during mounting or scanning. Here, we describe the preparation, stabilization, dehydration and mounting of large soft-tissue samples for X-ray microtomography. We detail the protocol applied to whole human organs and hierarchical phase-contrast tomography at the European Synchrotron Radiation Facility, yet it is applicable to a range of biological samples, including complete organisms. The protocol enhances the contrast when using X-ray imaging, while preventing sample motion during the scan, even with different sample orientations. Bubbles trapped during mounting and those formed during scanning (in the case of synchrotron X-ray imaging) are mitigated by multiple degassing steps. The sample preparation is also compatible with magnetic resonance imaging, computed tomography and histological observation. The sample preparation and mounting require 24-36 d for a large organ such as a whole human brain or heart. The preparation time varies depending on the composition, size and fragility of the tissue. Use of the protocol enables scanning of intact organs with a diameter of 150 mm with a local voxel size of 1 µm. The protocol requires users with expertise in handling human or animal organs, laboratory operation and X-ray imaging.

Weaning from noninvasive ventilatory support in infants with severe bronchiolitis: An observational study.

BACKGROUND: The aim of the study was to analyze the weaning success, the type of weaning procedures, and weaning duration in consecutive infants hospitalized in a pediatric intensive care unit over a winter season. METHODS: A retrospective observational study was conducted in a pediatric intensive care unit in a tertiary center. Infants hospitalized for severe bronchiolitis were included and the weaning procedure from continuous positive airway pressure (CPAP), noninvasive ventilation (NIV), or high-flow nasal cannula (HFNC) was analyzed. RESULTS: Data from 95 infants (median age, 47 days) were analyzed. On admission, 26 (27%), 46 (49%), and 23 (24%) infants were supported with CPAP, NIV, and HFNC, respectively. Weaning failed in one (4%), nine (20%), and one (4%) infants while supported with CPAP, NIV, or HFNC, respectively (p = 0.1). In infants supported with CPAP, CPAP was stopped directly in five patients (19%) while HFNC was used as an intermediate ventilatory support in 21 (81%). The duration of weaning was shorter for HFNC (17 h, [IQR: 0-26]) than for CPAP (24 h, [14-40]) and NIV (28 h, [19-49]) (p < 0.01). CONCLUSIONS: The weaning phase corresponds to a large proportion of noninvasive ventilatory support duration in infants with bronchiolitis. The weaning procedure following a "step-down" strategy may lead to an increase in the duration of weaning.

Mechanical ventilation during cardiopulmonary resuscitation: influence of positive end-expiratory pressure and head-torso elevation.

BACKGROUND: Efficient ventilation is important during cardiopulmonary resuscitation (CPR). Nevertheless, there is insufficient knowledge on how the patient's position affects ventilatory parameters during mechanically assisted CPR. We studied ventilatory parameters at different positive end-expiratory pressure (PEEP) levels and when using an inspiratory impedance valve (ITD) during horizontal and head-up CPR (HUP-CPR). METHODS: In this human cadaver experimental study, we measured tidal volume (VT) and pressure during CPR at different randomized PEEP levels (0, 5 or 10 cmH2O) or with an ITD. CPR was performed, in the following order: horizontal (FLAT), at 18° and then at 35° head-thorax elevation. During the inspiratory phase we measured the net tidal volume (VT) adjusted to predicted body weight (VTPBW), reversed airflow (RAF), and maximum and minimum airway pressure (Pmax and Pmin). RESULTS: Using ten thawed fresh-frozen cadavers we analyzed the inspiratory phase of 1843 respiratory cycles, 229 without CPR and 1614 with CPR. In a mixed linear model, thoracic position and PEEP significantly impacted VTPBW (p < 0.001 for each), and the insufflation time, thoracic position and PEEP significantly affected the RAF (p < 0.001 for each) and Pmax (p < 0.001). For Pmin, only PEEP was significant (p < 0.001). In subgroup analysis, at 35° VTPBW and Pmax were significantly reduced compared with the flat or 18° position. CONCLUSION: When using mechanical ventilation during CPR, it seems that the PEEP level and patient position are important determinants of respiratory parameters. Moreover, tidal volume seems to be lower when the thorax is positioned at 35°.

Supraglottic Airway Device to Improve Ventilation Success and Reduce Pulmonary Aspiration during Cardio-Pulmonary Resuscitation by Basic Life Support Rescuers: A Randomized Cross-over Human Cadaver Study.

OBJECTIVES: Early airway management during cardiopulmonary resuscitation (CPR) prevents aspiration of gastric contents. Endotracheal intubation is the gold standard to protect airways, but supraglottic airway devices (SGA) may provide some protection with less training. Bag-mask ventilation (BMV) is the most common method used by rescuers. We hypothesized that SGA use by first rescuers during CPR could increase ventilation success rate and also decrease intragastric pressure and pulmonary aspiration. METHODS: We performed a randomized cross-over experimental trial on human cadavers. Protocol A: we assessed the rate of successful ventilation (chest rise), intragastric pressure, and CPR key time metrics. Protocol B: cadaver stomachs were randomized to be filled with 300 mL of either blue or green serum saline solution through a Foley catheter. Each rescuer was randomly assigned to use SGA or BMV during a 5-minute standard CPR period. Then, in a crossover design, the stomach was filled with the second color solution and another 5-minute CPR period was performed using the other airway method. Pulmonary aspiration, defined as the presence of colored solution below the vocal cords, was assessed by a blinded operator using bronchoscopy. A generalized linear mixed model was used for statistical analysis. RESULTS: Protocol A: Forty-eight rescuers performed CPR on 11 cadavers. Median ventilation success was higher with SGA than BMV: 75.0% (IQR: 59.8-87.3) vs. 34.7% (IQR: 25.0-50.0), (p = 0.003). Gastric pressure and differential (maximum minus minimum) gastric pressure were lower in the SGA group: 2.21 mmHg (IQR: 1.66; 2.68) vs. 3.02 mmHg (IQR: 2.02; 4.22) (p = 0.02) and 5.70 mmHg (IQR: 4.10; 7.60) vs. 8.05 mmHg (IQR: 5.40; 11.60) (p = 0.05). CPR key times were not different between groups. Protocol B: Ten cadavers were included with 20 CPR periods. Aspiration occurred in 2 (20%) SGA procedures and 5 (50%) BMV procedures (p = 0.44). CONCLUSION: Use of SGA by rescuers improved the ventilation success rate, decreased intragastric pressure, and did not affect key CPR metrics. SGA use by basic life support rescuers appears feasible and efficient.

An inferior vena cava discontinuity with an hepato-renal accessory vein development: A radio-anatomical morphometric case study.

PURPOSE: Inferior vena cava (IVC) agenesis is an uncommon congenital vascular anomaly stemming from aberrant development during embryogenesis. It results from the failure of one or more of the supracardinal veins, subcardinal veins, vitelline veins or postcardinal veins to connect. The symptomatology resulting from this vascular malformation can be either absent or extremely rich and varied. METHODS: Thoracoabdominal-pelvic CT scan projections following iodine-based contrast product injection were analyzed and a three-dimensional model of vascularization constructed. RESULTS: Herein, an asymptomatic case of IVC agenesis with absence of the suprarenal and renal segments, with azygos continuation, presenting an accessory hepatorenal vein is reported. The presence of this type of accessory vein has never been described in the literature to date. The etiology of this case of IVC agenesis is explored in depth. We also analyzed the morphometric parameters of the IVC remnant segments and the azygos vein in order to quantify the dilatation of the collateral venous pathway overdeveloped to handle blood return. CONCLUSION: Using the findings from this case and those reported in the literature, we provide general recommendations that should be taken into account before managing a patient, symptomatic or asymptomatic, admitted to the hospital with IVC agenesis.

Imaging intact human organs with local resolution of cellular structures using hierarchical phase-contrast tomography.

Imaging intact human organs from the organ to the cellular scale in three dimensions is a goal of biomedical imaging. To meet this challenge, we developed hierarchical phase-contrast tomography (HiP-CT), an X-ray phase propagation technique using the European Synchrotron Radiation Facility (ESRF)'s Extremely Brilliant Source (EBS). The spatial coherence of the ESRF-EBS combined with our beamline equipment, sample preparation and scanning developments enabled us to perform non-destructive, three-dimensional (3D) scans with hierarchically increasing resolution at any location in whole human organs. We applied HiP-CT to image five intact human organ types: brain, lung, heart, kidney and spleen. HiP-CT provided a structural overview of each whole organ followed by multiple higher-resolution volumes of interest, capturing organotypic functional units and certain individual specialized cells within intact human organs. We demonstrate the potential applications of HiP-CT through quantification and morphometry of glomeruli in an intact human kidney and identification of regional changes in the tissue architecture in a lung from a deceased donor with coronavirus disease 2019 (COVID-19).

Anatomical study of the thoracic duct and its clinical implications in thoracic and pediatric surgery, a 70 cases cadaveric study.

INTRODUCTION: Given the high variability and fragility of the thoracic duct, good knowledge of its anatomy is essential for its repair or to prevent iatrogenic postoperative chylothorax. The objective of this study was to define a site where the thoracic duct is consistently found for its ligation. The second objective was to define an anatomically safe surgical pathway to prevent iatrogenic chylothorax in surgery for aortic arch anomalies with vascular ring, through better knowledge of the anatomical relationships of the thoracic duct. METHODS: Seventy adult formalin-fixed cadavers were dissected. The anatomical relationships of the thoracic duct were reported at the postero-inferior mediastinum, at levels T3 and T4. RESULTS: The thoracic duct was consistently situated between the left anterolateral border of the azygos vein and the right border of the aorta between levels T9 and T10, whether it was simple, double, or plexiform. It was located medially, anteromedially, or posteriorly to the left subclavian artery in 51%, 21%, and 28% of the cases, respectively, at the level of T3. At T4, it was posteromedial in 27% of the cases or had no direct relationship with the aortic arch. CONCLUSION: These results favor mass ligation of the thoracic duct at levels T9-T10 between the right border of the aorta and the azygos vein, eventually including the latter. To prevent iatrogenic postoperative chylothorax in aortic arch anomalies with vascular ring surgery, we recommend remaining strictly lateral to the left subclavian artery at the level of T3 to reach the aortic arch anomalies with vascular ring at T4.

Multiscale three-dimensional imaging of intact human organs down to the cellular scale using hierarchical phase-contrast tomography.

Human organs are complex, three-dimensional and multiscale systems. Spatially mapping the human body down through its hierarchy, from entire organs to their individual functional units and specialised cells, is a major obstacle to fully understanding health and disease. To meet this challenge, we developed hierarchical phase-contrast tomography (HiP-CT), an X-ray phase propagation technique utilising the European Synchrotron Radiation Facility's Extremely Brilliant Source: the world's first high-energy 4 th generation X-ray source. HiP-CT enabled three-dimensional and non-destructive imaging at near-micron resolution in soft tissues at one hundred thousand times the voxel size whilst maintaining the organ's structure. We applied HiP-CT to image five intact human parenchymal organs: brain, lung, heart, kidney and spleen. These were hierarchically assessed with HiP-CT, providing a structural overview of the whole organ alongside detail of the organ's individual functional units and cells. The potential applications of HiP-CT were demonstrated through quantification and morphometry of glomeruli in an intact human kidney, and identification of regional changes to the architecture of the air-tissue interface and alveolar morphology in the lung of a deceased COVID-19 patient. Overall, we show that HiP-CT is a powerful tool which can provide a comprehensive picture of structural information for whole intact human organs, encompassing precise details on functional units and their constituent cells to better understand human health and disease.

Cadaver models for cardiac arrest: A systematic review and perspectives.

AIM: To provide an overview of cadaver models for cardiac arrest and to identify the most appropriate cadaver model to improve cardiopulmonary resuscitation through a systematic review. METHODS: The search strategy included PubMed, Embase, Current contents, Pascal, OpenSIGLE and reference tracking. The search concepts included "heart arrest", "cardiopulmonary resuscitation" and "cadavers". All studies, published until February 2019, in English or French, on research or simulation in the field of cardiac arrest and using cadaver models were eligible for inclusion. RESULTS: Overall, 29 articles out of the 244 articles located were selected. The characteristics of the studies and the cadaver models were heterogenous. Indeed, 31% of the studies lacked a proper description of the model used and its specificities. Fresh cadavers were used in 55% of the studies and chest compressions were performed in 90%. This model was appreciated for its realism in terms of mechanical properties and tissue conservation. Thiel-embalmed cadavers also showed promising results concerning lung and chest compliance. The lack of circulation stood out as the strongest limitation of all types of human cadaver models. CONCLUSION: Four types of cadaver models are used in cardiac arrest research. The great heterogeneity of these models coupled with unequal quality in reporting makes comparisons between studies difficult. There is a need for uniform reporting and standardisation of human cadaver models in cardiac arrest research.

Feedback on the usefulness of an illustrated guidebook in an anatomical dissection course.

PURPOSE: Dissection provides direct experience in anatomy, which constitutes an essential discipline for medical students. For this purpose, we created a dissection guide for students in the 2nd-year of medical studies at the Grenoble University School of Medicine. The objective was to evaluate this tool of reverse pedagogy in terms of student satisfaction and educational interest. METHODS: Every 2nd-year student takes four sessions of limb dissection. To assist this dissection course, we developed a photographic guide launched in 2013. It includes an introduction presenting a methodology for dissection, followed by detailed protocols for each dissection area. Each step is illustrated with captioned photographs associated with a concise explanatory text. A questionnaire was then sent to 242 students to assess the impact of this tool and their overall satisfaction. RESULTS: Overall student satisfaction with this guidebook was rated 8.1 out of 10 with a 93.2% with significant improvement (p = 0.0137) and 78.7% of them declaring they had a better understanding of anatomy and mastery of the dissection techniques, respectively. In addition, students assessed the usefulness of the dissection guide at 3.6 out of 4 with the relevance of the content and presentation judged at 3.4 out of 4. Finally, the exam scores increased significantly with use of the guidebook (p < 0.0001). CONCLUSIONS: Students deemed the organization of this anatomy tutorial as highly satisfactory, and using the guidebook as a reference in dissection sessions allowed students to prepare for the dissection and improve their knowledge of anatomy, as demonstrated by improved exam scores.

The round ligament of the uterus: Questioning its distal insertion.

PURPOSE: Classically, the round ligament of the uterus (RLU) attaches distally in the ipsilateral labia majora. This attachment has rarely been described in adults. That is why we have performed an anatomical study focused on this distal ending. PATIENTS: We performed in 2015 the cadaveric dissection of 19 RLU. METHODS: In all cases, the RLU was individualized on its entire length from its uterine origin to the inguinal canal. Then this canal was open from its internal orifice to its external orifice. We described the distal attachment of the RLU according four areas: before the internal inguinal ring, after the external inguinal ring, under the pubic bone and in labia majora. RESULTS: We found 3 types of distal attachments with first an attachment after the external inguinal ring in more than half of cases (52.6%). Then, before the internal inguinal ring (26.3%) and under the pubic bone (22.1%). No RLU was found inlabia majora. However, the proximal attachment seems constant at the antero-superior face of uterus, near the tubo-uterine junction like its pelvic path under the broad ligament. CONCLUSION: In adult, the RLU is a structure, which begins at the cranio-ventral part of the uterine bottom near the tubo-uterine junction. Then it passes under the broad ligament and reaches the inguinal canal, that it crosses in more half of cases. However, 3 distal attachment areas have been identified but never in the labia majora. Indeed, some anatomical information available in anatomical treaties seems not correct and should be amended.

Techniques of cadaver perfusion for surgical training: a systematic review.

PURPOSE: The objective of this study was to identify the most appropriate cadaver perfusion techniques for surgical training through a systematic review with a description of the protocols used. METHODS: The search strategy included PubMed and reference tracking. Studies were identified by searching the electronic Medline databases. The search concepts included perfusion, cadavers and simulation training, and the protocol used is reported. This resulted in a qualitative review of 12 articles out of 250 articles consulted. We collected all the important data from these 12 articles. RESULTS: Regarding the characteristics of the studies and the declotting or perfusion techniques, the results were heterogeneous. Indeed, in several studies, a good deal of information was unclear or insufficiently precise, making it unfeasible to summarize the data. The methods used were not sufficiently explicit and detailed. However, a majority of the fresh cadavers used tap water for declotting. Perfusion, type of fluid, number of pumps, pressure, pulsatility, and arterial or venous approaches differed greatly. Only two studies fulfilled five of our six realism criteria for surgical simulation. CONCLUSIONS: This systematic review provided an overview of all the different cadaver perfusion techniques. It could be used to establish a reference method of a simulation model.

Relationship between the ansa cervicalis and the omohyoid muscle: clinical consequences in parathyroid surgery.

PURPOSE: To determine the position of the lower loop of the ansa cervicalis (AC) compared to the inferior edge of the omohyoid muscle to guide minimally invasive surgery for the lateral oblique approach of parathyroid glands. METHODS: Authors performed 36 anatomical dissections in the laboratory of anatomy (Laboratoire d'Anatomie Des Alpes Françaises) of the Grenoble medical school in 2012 on human cadavers. They independently measured the distance between the caudal extremity of the AC and the lower edge of the superior belly of the omohyoid muscle. Then, they controlled this measure on pictures. RESULTS: The study shows a majority of long AC (under the omohyoid muscle) in 66.7 % of cases. In addition, the AC was located on an average value of 0.1 cm below the lower edge of the omohyoid muscle (median -0.5 cm). Thus, two-thirds of AC are between 0 and -2 cm under the omohyoid muscle. Furthermore, the AC is generally non-symmetrical: there is a mean difference of 1.3 cm between the left and right AC. In this series, there are as many long AC on the right side as on the left side. CONCLUSIONS: These results are in contradiction with literature data. To preserve the ansa cervicalis and its phonatory functions, it is necessary for the surgeon to perform a systematic per operative identification of the AC because the position of the AC is mainly under the omohyoid muscle and because of an asymmetry. Per operative neurostimulation and/or magnified lenses might be helpful during the surgical approach.