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Introduction: Elite breath-hold divers (BHD) enduring apneas of more than 5 min are characterized by tolerance to arterial blood oxygen levels of 4.3 kPa and low oxygen-consumption in their hearts and skeletal muscles, similar to adult seals. Adult seals possess an adaptive higher hemoglobin-concentration and Bohr effect than pups, and when sedated, adult seals demonstrate a blood shift from the spleen towards the brain, lungs, and heart during apnea. We hypothesized these observations to be similar in human BHD. Therefore, we measured hemoglobin- and 2,3-biphosphoglycerate-concentrations in BHD (n = 11) and matched controls (n = 11) at rest, while myocardial mass, spleen and lower extremity volumes were assessed at rest and during apnea in BHD. Methods and results: After 4 min of apnea, left ventricular myocardial mass (LVMM) determined by 15O-H2O-PET/CT (n = 6) and cardiac MRI (n = 6), was unaltered compared to rest. During maximum apnea (∼6 min), lower extremity volume assessed by DXA-scan revealed a ∼268 mL decrease, and spleen volume, assessed by ultrasonography, decreased ∼102 mL. Compared to age, BMI and VO2max matched controls (n = 11), BHD had similar spleen sizes and 2,3- biphosphoglycerate-concentrations, but higher total hemoglobin-concentrations. Conclusion: Our results indicate: 1) Apnea training in BHD may increase hemoglobin concentration as an oxygen conserving adaptation similar to adult diving mammals. 2) The blood shift during dry apnea in BHD is 162% more from the lower extremities than from the spleen. 3) In contrast to the previous theory of the blood shift demonstrated in sedated adult seals, blood shift is not towards the heart during dry apnea in humans., Introduction: Elite breath-hold divers (BHD) enduring apneas of more than 5 min are characterized by tolerance to arterial blood oxygen levels of 4.3 kPa and low oxygen-consumption in their hearts and skeletal muscles, similar to adult seals. Adult seals possess an adaptive higher hemoglobin-concentration and Bohr effect than pups, and when sedated, adult seals demonstrate a blood shift from the spleen towards the brain, lungs, and heart during apnea. We hypothesized these observations to be similar in human BHD. Therefore, we measured hemoglobin- and 2,3-biphosphoglycerate-concentrations in BHD (n = 11) and matched controls (n = 11) at rest, while myocardial mass, spleen and lower extremity volumes were assessed at rest and during apnea in BHD. Methods and results: After 4 min of apnea, left ventricular myocardial mass (LVMM) determined by 15O-H2O-PET/CT (n = 6) and cardiac MRI (n = 6), was unaltered compared to rest. During maximum apnea (∼6 min), lower extremity volume assessed by DXA-scan revealed a ∼268 mL decrease, and spleen volume, assessed by ultrasonography, decreased ∼102 mL. Compared to age, BMI and VO2max matched controls (n = 11), BHD had similar spleen sizes and 2,3- biphosphoglycerate-concentrations, but higher total hemoglobin-concentrations. Conclusion: Our results indicate: 1) Apnea training in BHD may increase hemoglobin concentration as an oxygen conserving adaptation similar to adult diving mammals. 2) The blood shift during dry apnea in BHD is 162% more from the lower extremities than from the spleen. 3) In contrast to the previous theory of the blood shift demonstrated in sedated adult seals, blood shift is not towards the heart during dry apnea in humans.

Introduction: The cardiac electrical conduction system is very sensitive to hypoglycemia and hypoxia, and the consequence may be brady-arrythmias. Weddell seals endure brady-arrythmias during their dives when desaturating to 3.2 kPa and elite breath-hold-divers (BHD), who share metabolic and cardiovascular adaptions including bradycardia with diving mammals, endure similar desaturation during maximum apnea. We hypothesized that hypoxia causes brady-arrythmias during maximum apnea in elite BHD. Hence, this study aimed to define the arterial blood glucose (Glu), peripheral saturation (SAT), heart rhythm (HR), and mean arterial blood pressure (MAP) of elite BHD during maximum apneas. Methods: HR was monitored with Direct-Current-Pads/ECG-lead-II and MAP and Glu from a radial arterial-catheter in nine BHD performing an immersed and head-down maximal static pool apnea after three warm-up apneas. SAT was monitored with a sensor on the neck of the subjects. On a separate day, a 12-lead-ECG-monitored maximum static apnea was repeated dry (n = 6). Results: During pool apnea of maximum duration (385 ± 70 s), SAT decreased from 99.6 ± 0.5 to 58.5 ± 5.5% (∼PaO2 4.8 ± 1.5 kPa, P < 0.001), while Glu increased from 5.8 ± 0.2 to 6.2 ± 0.2 mmol/l (P = 0.009). MAP increased from 103 ± 4 to 155 ± 6 mm Hg (P < 0.005). HR decreased to 46 ± 10 from 86 ± 14 beats/minute (P < 0.001). HR and MAP were unchanged after 3-4 min of apnea. During dry apnea (378 ± 31 s), HR decreased from 55 ± 4 to 40 ± 3 beats/minute (P = 0.031). Atrioventricular dissociation and junctional rhythm were observed both during pool and dry apneas. Conclusion: Our findings contrast with previous studies concluding that Glu decreases during apnea diving. We conclude during maximum apnea in elite BHD that (1) the diving reflex is maximized after 3-4 min, (2) increasing Glu may indicate lactate metabolism in

Background: The performance of elite breath hold divers (BHD) includes static breath hold for more than 11 minutes, swimming as far as 300 m, or going below 250 m in depth, all on a single breath of air. Diving mammals are adapted to sustain oxidative metabolism in hypoxic conditions through several metabolic adaptations, including improved capacity for oxygen transport and mitochondrial oxidative phosphorylation in skeletal muscle. It was hypothesized that similar adaptations characterized human BHD. Hence, the purpose of this study was to examine the capacity for oxidative metabolism in skeletal muscle of BHD compared to matched controls. Methods: Biopsies were obtained from the lateral vastus of the femoral muscle from 8 Danish BHD and 8 non-diving controls (Judo athletes) matched for morphometry and whole body VO2max. High resolution respirometry was used to determine mitochondrial respiratory capacity and leak respiration with simultaneous measurement of mitochondrial H2O2 emission. Maximal citrate synthase (CS) and 3-hydroxyacyl CoA dehydrogenase (HAD) activity were measured in muscle tissue homogenates. Western Blotting was used to determine protein contents of respiratory complex I-V subunits and myoglobin in muscle tissue lysates. Results: Muscle biopsies of BHD revealed lower mitochondrial leak respiration and electron transfer system (ETS) capacity and higher H2O2 emission during leak respiration than controls, with no differences in enzyme activities (CS and HAD) or protein content of mitochondrial complex subunits myoglobin, myosin heavy chain isoforms, markers of glucose metabolism and antioxidant enzymes.Conclusion: We demonstrated for the first time in humans, that the skeletal muscles of BHD are characterized by lower mitochondrial oxygen consumption both during low leak and high (ETS) respiration than ma

Closure of persistent foramen ovale (PFO) to avoid cryptogenic strokes is performed globally with enthusiasm but lacks prove of efficacy. We present a 79-year-old man who had had a PFO device introduced nine years previously because of cryptogenic strokes presenting as syncopes. The patient was referred from his general practitioner with two new syncopes. Transthoracic echocardiography revealed no cardiac causes of embolism. Transesophageal echocardiography (TEE) revealed a misplaced device like an umbrella in a storm, but no septum defects. Holter revealed seconds-long episodes of atrial fibrillation (AF). The patient was successfully treated with anticoagulation. A literature review showed that: (i) the efficacy of PFO closure devices has not been proven in any trial, but was demonstrated in a meta-analysis comparing three different devices; (ii) PFO devices are rarely controlled by TEE during or after insertion; (iii) residual shunts are detected in up to 45% of cases; (iv) there is an increased rate of post-arrhythmic complications; (v) the risk of AF in congenital heart disease increases with increasing age, with a 13% risk of transient ischemic attacks and stroke; and (vi) surgical treatment of PFO was found to have a 4.1% risk of complications including stroke. The question to be asked is whether device closure of PFO should be avoided, considering that PFO is a congenital heart defect with risks of AF and (cryptogenic) stroke? Heart surgery should be a treatment option for symptomatic PFO.

INTRODUCTION: Reasoning in a clinical context is an attribute of medical expertise. Clinical reasoning in medical school can be encouraged by teaching basic science with a clinical emphasis. The aim of this study was to investigate whether anatomy is being taught in a way that facilitates the development of clinical reasoning.MATERIALS AND METHODS: Two multiple-choice tests on thoracic anatomy were developed using a modified Delphi approach with groups of four clinical consultants and four teachers, respectively, expressing their opinions about knowledge relevant to thoracic anatomy. Validity was assessed by administering the tests to clinical consultants, anatomy teachers, and pre-course medical students. Post-course medical students took both tests to explore the focus of the course, i.e., whether it facilitated clinical reasoning.RESULTS: The pre-course students scored significantly lower than the teachers and post-course students on both tests and lower than the consultants on the consultants' test (P < 0.001 for all comparisons). The teachers significantly outperformed the consultants (P = 0.03 on the consultants' test, P < 0.001 on the teachers' test) and the medical students (P < 0.001 on both tests). The post-course students scored significantly lower on the consultants' test (P = 0.001) and significantly higher on the teachers' test (P = 0.02) than the consultants.CONCLUSIONS: This study demonstrates poor performances by medical students on a test containing clinically relevant anatomy, implying that the teaching they have received has not encouraged clinical reasoning. Clin. Anat., 2015. © 2015 Wiley Periodicals, Inc.

Background: There have been several attempts to systematically assess performance in bronchoscopy. Earlier validation studies have used bronchoscopy simulators, not real-life performance in patients. Objectives: The aim of this study was to explore the reliability and validity of an assessment tool aimed for the use in a clinical setting. Methods: Five junior residents, 5 senior residents and 9 consultants performed 3 bronchoscopies each. All 57 bronchoscopies were video-recorded and assessed blindly and independently by two bronchoscopy experts using the new assessment tool. Results: The interrater reliability was high, with Cronbach's a = 0.86. Assessment of 3 bronchoscopies by a single rater had a generalizability coefficient of 0.84. The correlation between experience and performance was good (Pearson correlation = 0.76). There were significant differences between the groups for all aspects of the assessment, but post hoc tests showed different discriminative abilities. Conclusions: This new tool for assessing clinical bronchoscopy performance has a high interrater reliability. One rater assessing performance of 3 bronchoscopies ensures sufficient reliability. The assessment tool demonstrated sufficient construct validity.

PURPOSE: The aim of this study, done in Denmark, was to explore the construct validity of a Reporter-Interpreter-Manager-Educator (RIME)-structured scoring format for assessing patient encounter skills. METHOD: The authors developed a RIME-structured scoring form and explored its construct validity in a two-step procedure. The first step (implemented in 2009) was a randomized, controlled, experimental study in which the performance of three groups (16 fourth-year medical students, 16 sixth-year medical students, and 16 interns) was assessed in two simulated patient encounters. The second step (carried out during 2009-2010) was an observational study of patient encounter skills where clinician examiners used the scoring form in end-of-clerkship oral examinations of three consecutive cohorts of a total of 547 fourth-year medical students. RESULTS: In the experimental study, RIME scores showed significant difference between the three groups-fourth-year students, mean 41.7 (standard deviation [SD] 11.0); sixth-year students, mean 48.2 (SD 10.9); and interns, mean 61.9 (SD 8.5), one-way ANOVA, P <.0001-and showed a progression over the four RIME elements with participants' increasing competence.In the observational study, the mean RIME score was higher (83.8 [SD 15.5]), and advanced RIME levels were frequently missing or scored "not relevant" by the clinician examiners. CONCLUSION: In an experimental setup, the RIME structure demonstrated construct validity in terms of reflecting progress in competence in managing patient encounters when assessed according to an advanced criterion. However, clinician examiners may tacitly score the elements according to what can be expected at a certain level of student experience.

Background: Virtual reality (VR) bronchoscopy simulators have been available for more than a decade, and have been recognized as an important aid in bronchoscopy training. The existing literature has only examined the role of VR simulators in diagnostic bronchoscopy. The aim of this study was to find out whether the simulations of both diagnostic bronchoscopies and more advanced procedures were realistic, and whether clinical experience in bronchoscopy was associated with better and faster performance of basic pulmonary procedures in the simulator. Methods: Thirty physicians performed 8 procedures, each on a VR bronchoscopy simulator. They performed 3 diagnostic bronchoscopies, 2 bronchoalveolar lavages, and 3 procedures in which they used all the available biopsy tools (needle, brush, and forceps) that could be used for tumors of increasing procedural difficulty. After the procedures, the physicians answered a questionnaire regarding the realism of the simulator. Results: The realism of the anatomy and the appearance of the scope were rated higher than the movement of the scope, feeling of resistance, and performances of bronchoalveolar lavages and biopsies. Overall, the simulator was judged to be realistic and all the physicians agreed that VR bronchoscopy simulation is a good way to learn bronchoscopy. The more experienced physicians performed faster than the less experienced physicians. The simulator feedback did not allow for an assessment of the quality of the performed biopsies. Conclusions: Simulation of performing the procedures was significantly less realistic than the simulation of the anatomy and the scope. It was impossible to use the simulator metrics to assess the quality of the biopsies. Despite these deficiencies, clinicians recommend the use of VR simulators in the teaching of pulmonary procedures.

Background: International guidelines suggest that trainees should perform at least 100 flexible bronchoscopies in a supervised setting, but this number is not evidence based. An objective assessment method could provide educational feedback to trainees and help supervisors decide when basic competency is established. No former assessment instrument has been able to distinguish between trainees and experts. Objectives: The aim of this study was to explore the validity and reliability of a new assessment procedure relating to testing operators across multiple tasks with increasing difficulty using a standardized scoring form. Methods: The test was administered on a virtual reality bronchoscopy simulator to a total of 42 test subjects (14 senior consultants, 14 trainees and 14 medical students). The inter-rater reliability of the test procedure was explored according to examination of test results from 10 subjects using 3 raters (2 blinded). Results: We found a high inter-rater reliability (Cronbach's a = 0.90). The assessment procedure sufficiently differentiated the performance of the 3 groups (p <0.001). Assessment of 6 procedures was necessary to secure a generalizability coefficient >0.80. Conclusions: The new assessment procedure proved both valid and reliable.

Udgivelsesdato: 2009-Nov, Transcatheter aortic valve implantation (TAVI) is a relatively new treatment option for inoperable patients with severe aortic stenosis (AS). This case describes how a planned conventional surgical aortic valve replacement (AVR) on a 73-year-old woman was successfully converted to a TAVI procedure. On extracorporal circulation it was reconized that the aortic annulus, the coronary ostiae and the proximal part of the ascending aorta were severely calcified making valve implantation impossible. Surgical closure without valve substitution was estimated to be associated with a high risk of mortality due to the imparied left ventricular function. Consequently, TAVI was performed with a CoreValve ReValving System prosthesis. The delivery of the valve prosthesis was made through the ascending part of aorta, proximal of the cannulation of aorta. Positioning of the valve prosthesis was made under visual guidance, and the prosthesis was sutured to the ascending aorta. With some manipulation of the prosthesis it was possible to suture the aorta circumferentially around the fully expanded upper part of the prosthesis. Post-procedurally the patient recovered successfully, with improved function capacity, aortic valve area and left ventricle function.