Subdiaphragmatic phrenic nerve supply: A systematic review.

OBJECTIVE: The aim of this systematic review is to study the subdiaphragmatic anatomy of the phrenic nerve. MATERIALS AND METHODS: A computerised systematic search of the Web of Science database was conducted. The key terms used were phrenic nerve, subdiaphragmat*, esophag*, liver, stomach, pancre*, duoden*, intestin*, bowel, gangli*, biliar*, Oddi, gallbladder, peritone*, spleen, splenic, hepat*, Glisson, falciform, coronary ligament, kidney, suprarenal, and adrenal. The 'cited-by' articles were also reviewed to ensure that all appropriate studies were included. RESULTS: A total of one thousand three hundred and thirty articles were found, of which eighteen met the inclusion and exclusion criteria. The Quality Appraisal for Cadaveric Studies scale revealed substantial to excellent methodological quality of human studies, while a modified version of the Systematic Review Centre for Laboratory Animal Experimentation Risk of Bias Tool denoted poor methodological quality of animal studies. According to human studies, phrenic supply has been demonstrated for the gastro-esophageal junction, stomach, celiac ganglia, liver and its coronary ligament, inferior vena cava, gallbladder and adrenal glands, with half of the human samples studied presenting phrenic nerve connections with any subdiaphragmatic structure. CONCLUSIONS: This review provides the first systematic evidence of subdiaphragmatic phrenic nerve supply and connections. This is of interest to professionals who care for people suffering from neck and shoulder pain, as well as patients with peridiaphragmatic disorders or hiccups. However, there are controversies about the autonomic or sensory nature of this supply.

Surgical Diaphragm: Anatomy and Physiology.

The diaphragm is a musculoaponeurotic structure separating the thoracic and abdominal cavities. It plays important roles in both respiration and maintaining gastrointestinal function. A careful consideration of anatomy should be taken during surgical procedures to minimize injury to this crucial organ.

A morphological study of the inferior phrenic arteries on multidetector computed tomography and angiography.

INTRODUCTION: The inferior phrenic artery is a paired artery with a variable origin and course, primarily supplying the diaphragm, but also the suprarenal glands, inferior vena cava, stomach, and oesophagus. The aim of this study is to investigate the origin and course of the inferior phrenic arteries on multidetector computed tomography and angiography. MATERIALS AND METHODS: The anatomy of the inferior phrenic artery was analysed on 2449 multidetector computed tomography scans. Three-dimensional reconstructions were made of the main variations. Additionally, the course and branching pattern of the inferior phrenic artery were descriptively analysed in a cohort of 28 angiograms. RESULTS: In 565 (23.1%) cases the inferior phrenic arteries arose as a common trunk and in 1884 (76.9%) cases as individual vessels. The most common origins of a common trunk were the coeliac trunk (n=303; 53.6%) and abdominal aorta (n=255; 45.1%). The most common origins of the right inferior phrenic artery were the coeliac trunk (n=965; 51.2%), abdominal aorta (n=562; 29.8%) and renal arteries (n=214; 11.4%). The most common origins of the left inferior phrenic artery were the coeliac trunk (n=1293; 68.6%) and abdominal aorta (n=403; 21.4%). CONCLUSION: The inferior phrenic artery has a very variable anatomy. The most common origins of the inferior phrenic artery are the coeliac trunk and its branches, the abdominal aorta, and the renal arteries.

Deep Diaphragmatic Breathing-Anatomical and Biomechanical Consideration.

Background: Deep diaphragmatic breathing (DDB) involves slow and fully contraction of the diaphragm with expansion of the belly during inhalation, and slow and fully contraction of the abdominal muscles with reduction of the belly during exhalation. It is the key component of the holistic mind-body exercises commonly used for patients with multimorbidity. Purpose: The purpose of this study was to re-visit and address the fundamental anatomical and biomechanical consideration of the DDB with the relevant literature. Method: Peer-reviewed publications from last the 15 years were retrieved, reviewed, and analyzed. Findings: In this article, we described the updated morphological and anatomical characteristics of the diaphragm. Then, we elucidated in a biomechanical approach how and why the DDB can work on the gastrointestinal, cardiopulmonary, and nervous systems as well as on regulating the intra-abdominopelvic pressure and mind-body interaction to coordinate the diaphragm-pelvic floor-abdominal complex for a variety of physical and physiological activities. Conclusion: Understanding of this updated DDB knowledge may help holistic healthcare professionals including holistic nurses provide better patient education and care management during the DDB or DDB-based mind-body intervention time.

Effects of intradialytic inspiratory muscle training at different intensities on diaphragm thickness and functional capacity: clinical trial protocol in patients undergoing haemodialysis.

INTRODUCTION: Patients with end-stage renal disease (ESRD) undergoing haemodialysis (HD) commonly present with a sedentary behaviour and reduced functional capacity, factors that can compromise their prognosis. Intradialytic inspiratory muscle training (IMT) can increase respiratory muscle strength and, consequently, improve functional capacity, besides being easy to apply, cheap and performed in a supervised setting. However, few studies show the effects of this type of training applied at different intensities in this population. This study aims to compare the effects of IMT at different intensities in adults with ESRD undergoing HD. METHODS AND ANALYSIS: A randomised, double-blind, sham-controlled trial will be conducted on 36 subjects randomly allocated into three groups: IMT at intensities of 30% or 50% of maximal inspiratory pressure (intervention groups), or 10% of maximal inspiratory pressure (sham-IMT). All the interventions will be supervised and performed three times per week, for 12 weeks, totalling 36 sessions. The primary outcomes are the 6-minute walk test, diaphragm thickness and the response of VO2peak post-intervention. Respiratory muscle strength, 24-hour ambulatory blood pressure measurement and the Kidney Disease Quality of Life 36-item short form survey will be evaluated as secondary outcomes. ETHICS AND DISSEMINATION: This study has been approved by the Research Ethics Committee of the Hospital de Clínicas de Porto Alegre (ID: 2020-0458). The results of this study will be disseminated by conference presentations and peer-reviewed journal. TRIAL REGISTRATION NUMBER: NCT04660383.

Anatomy and pathology of lymphatic vessels under physiological and inflammatory conditions in the mouse diaphragm.

The lymphatic vessels in the parietal pleura drain fluids. Impaired drainage function and excessive fluid entry in the pleural cavity accumulate effusion. The rat diaphragmatic lymphatics drain fluids from the pleura to the muscle layer. Lymphatic subtypes are characterized by the major distribution of discontinuous button-like endothelial junctions (buttons) in initial lymphatics and continuous zipper-like junctions (zippers) in the collecting lymphatics. Inflammation replaced buttons with zippers in tracheal lymphatics. In the mouse diaphragm, the structural relationship between the lymphatics and blood vessels, the presence of lymphatics in the muscle layer, and the distributions of initial and collecting lymphatics are unclear. Moreover, the endothelial junctional alterations and effects of vascular endothelial growth factor receptor (VEGFR) inhibition under pleural inflammation are unclear. We subjected the whole-mount mouse diaphragms to immunohistochemistry. The lymphatics and blood vessels were distributed in different layers of the pleural membrane. Major lymphatic subtypes were initial lymphatics in the pleura and collecting lymphatics in the muscle layer. Chronic pleural inflammation disorganized the stratified layers of the lymphatics and blood vessels and replaced buttons with zippers in the pleural lymphatics, which impaired drainage function. VEGFR inhibition under inflammation maintained the vascular structures and drainage function. In addition, VEGFR inhibition maintained the lymphatic endothelial junctions and reduced the blood vessel permeability under inflammation. These findings may provide new targets for managing pleural effusions caused by inflammation, such as pleuritis and empyema, which are common pneumonia comorbidities.

Influence of gender on diaphragm thickness using a method for determining intima media thickness in healthy young adults.

BACKGROUND: To clarify the differences in diaphragm thickness between male and female participants in healthy young adults with ultrasonography using the mean intima media thickness (IMT) method and to investigate the relationship between diaphragm thickness and respiratory pressure. METHODS: Twenty-nine healthy individuals (16 females and 13 males) participated in the study. Diaphragm thickness was measured at total lung capacity (TLC) and at functional residual capacity (FRC) in each participant. We measured the diaphragm thickness using a method for mean intima media thickness. Moreover, change ratio of diaphragm thickness was calculated with the diaphragm thickness at TLC and FRC. RESULTS: Mean diaphragm thicknesses at FRC in males were significantly narrower than those in females (p < 0.001). The change ratio of diaphragm thickness was significantly augmented in males compared with that in females (p < 0.001). There was a positive correlation between the change ratio of diaphragm thickness and pulmonary function data and respiratory muscle strength in healthy young adults. CONCLUSIONS: The change ratio of diaphragm thickness using the IMT method can be accurately performed with a high degree of reproducibility by clinical laboratory technicians and may be a useful indicator for evaluating diaphragm muscle strength.

Ultrasound assessment of diaphragm thickness in athletes / Evaluación por ultrasonido del grosor del diafragma en atletas

SUMMARY: The main purpose of this study was to examine the correlation between the aerobic and anaerobic performance of diaphragm thickness in athletes. That study was conducted with 15 team athletes (TA) (age 21.80 ± 2.40 years), 15 individual athletes (IA) (age 18.93 ± 2.31 years) and the control group (CON) 10 people living sedentary lifestyles (age 23.60 ± 2.91 years). In this study, diaphragm muscle thickness (B-mode ultrasonography), respiratory function (spirometry and maximum inspiratory (MIP) and expiratory pressures (MEP), aerobic capacity yo-yo intermittent endurance Test 1 (YYIET-1), and anaerobic power by Monark 834 E were assessed. The diaphragm thickness was determined from the intercostalspace between the 8th and 9th ribs at the expiration time by ultrasound and from the intercostal space between the 10th and 11th ribs at inspiration and then, the thickness of the diaphragm was measured from the diaphragm is seen best. There was a positive correlation between DiTins (r= 0.477) and DiTins-ex (r= 0.473) parameters of TA. In IA, there was a significant correlation between DiTins and DiTins-ex parameters and Peak Power (r= 0.495 and 0.435, respectively) and average power (r= 0.483 and 0.446, respectively). No significant correlation in all parameters of the CON group (p<0.05). As a result, it was determined that athletes with high diaphragm thickness had higher anaerobic performance, and athletes with thinner diaphragm thickness had better VO2Max capacity. The diaphragm thickness of the athletes in individual branches was thicker than the team athletes, and their anaerobic performance was also higher.

RESUMEN: El objetivo principal de este estudio fue examinar la correlación entre el rendimiento aeróbico y anaeróbico del grosor del diaframa en atletas. Dicho estudio se realizó con 15 deportistas de equipo (TA) (edad 21,80 ± 2,40 años), 15 deportistas individuales (IA) (edad 18,93 ± 2,31 años) y el grupo control (CON) 10 personas con sedentarismo (edad 23,60 ± 2,91 años). Se midió, el grosor del diaframa (ultrasonografía en modo B), la función respiratoria (espirometría y presiones máximas inspiratorias (MIP) y espiratorias (MEP), prueba de resistencia intermitente yo- yo de capacidad aeróbica 1 (YYIET-1) y resistencia anaeróbica potencia por Monark 834 E. El grosor del diafragma se determinó a partir del espacio intercostal entre las costillas 8 y 9 en el momento de la espiración por ultrasonido y del espacio intercostal entre las costillas 10 y 11 en la inspiración. Hubo una correlación positiva entre los parámetros DiT ins (r= 0,477) y DiTins-ex (r= 0,473) de TA. En IA, hubo una correlación significativa entre los parámetros DiTins y DiTins-ex y el pico Potencia (r= 0,495 y 0,435, respectivamente) y potencia media (r= 0,483 y 0,446, respectivamente). No hubo correlación significativa en todos los parámetros del grupo CON (p<0,05). Como resultado, se determinó que los atletas con mayor espesor del diaframa tenían un mayor rendimiento anaeróbico, y los atletas con menor espesor del diaframa tenían una mejor capacidad de VO2Max. El grosor del diafragma de los atletas en ramas individuales fue mayor que el de los atletas de equipo, y su rendimiento anaeróbico también fue mayor.

Three-dimensional assessment of pharyngeal airway in individuals with myotonic dystrophy type 1

Background/aim: The objectives of this study were to assess pharyngeal airway volume (PAV) in patients with myotonic dystrophy type 1 (DM1) by cone-beam computerized tomography (CBCT) and to evaluate the impact of diaphragm thickness and pulmonary function tests on PAV. Materials and methods: Thirty DM1 patients (10 female and 20 male; mean age 42.40 ± 12.07) were included in the study. Age and sex-matched thirty patients were participated as control group. In DM1 group pulmonary function tests (PFT) were performed. Independent t-test was used to compare PAV values of patients with DM1 and control group. The Mann­Whitney U test was used to compare the parameters according to sex ( p < 0.05). Pearson and Spearman correlation tests were used to evaluate the relationships between parameters of DM1 patients (p < 0.05). A multiple linear regression analysis was performed to explain the PAV with parameters that showed positive correlation with PAV. Results: Age of onset and disease duration were 22.37 ± 8.45 and 20.03 ± 12.08, respectively, in patients with DM1. PAV values of control group were significantly lower than DM1 group ( p < 0.001). Forced expiratory volume in 1 s and forced volume vital capacity values were higher in males than females in DM1 group according to sex ( p < 0.001). PAV values were greater in male patients than females of the DM1 group ( p = 0.022). Diaphragm thickness in DM1 group after inspiration and expiration were 2.60 ± 0.65 and 1.94 ± 0.40, respectively. According to the regression analysis, DTai and FVC were significantly explained the PAV. Conclusion: PAV was higher in DM1 group. There was a significant positive correlation between diaphragm thickness, pulmonary functions, and PAVs of DM1 patients. The amount of the PAV was mostly influenced by DTai and FVC. It is recommended to evaluate the PAV in patients with DM1 because of impaired respiratory functions and pharyngeal muscle involvement.

Diaphragm thickening fraction predicts noninvasive ventilation outcome: a preliminary physiological study.

BACKGROUND: A correlation between unsuccessful noninvasive ventilation (NIV) and poor outcome has been suggested in de-novo Acute Respiratory Failure (ARF) patients. Consequently, it is of paramount importance to identify accurate predictors of NIV outcome. The aim of our preliminary study is to evaluate the Diaphragmatic Thickening Fraction (DTF) and the respiratory rate/DTF ratio as predictors of NIV outcome in de-novo ARF patients. METHODS: Over 36 months, we studied patients admitted to the emergency department with a diagnosis of de-novo ARF and requiring NIV treatment. DTF and respiratory rate/DTF ratio were measured by 2 trained operators at baseline, at 1, 4, 12, 24, 48, 72 and 96 h of NIV treatment and/or until NIV discontinuation or intubation. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the ability of DTF and respiratory rate/DTF ratio to distinguish between patients who were successfully weaned and those who failed. RESULTS: Eighteen patients were included. We found overall good repeatability of DTF assessment, with Intra-class Correlation Coefficient (ICC) of 0.82 (95% confidence interval 0.72-0.88). The cut-off values of DTF for prediction of NIV failure were < 36.3% and < 37.1% for the operator 1 and 2 (p < 0.0001), respectively. The cut-off value of respiratory rate/DTF ratio for prediction of NIV failure was > 0.6 for both operators (p < 0.0001). CONCLUSION: DTF and respiratory rate/DTF ratio may both represent valid, feasible and noninvasive tools to predict NIV outcome in patients with de-novo ARF. Trial registration ClinicalTrials.gov Identifier: NCT02976233, registered 26 November 2016.

Anatomy of Left Inferior Phrenic Vein in Patients Without Portal Hypertension.

OBJECTIVE. The left inferior phrenic vein (LIPV) can be an origin of a gastrorenal shunt from gastric varices. The purpose of our study was to evaluate the angiographic anatomy of the LIPV, particularly anastomoses of the LIPV with the portal vein (PV). SUBJECTS AND METHODS. Of 240 patients with primary aldosteronism who underwent adrenal venous sampling from April 2011 to July 2019, 236 had normal liver and renal function and were included in this study. Of those patients, 214 had evaluable LIPV venography. The angiographic anatomy of the LIPV was classified as type 1 when the subdiaphragmatic transverse part of the LIPV could be visualized or as type 2 when it could not. Type 1 was subclassified into type 1a, which was defined as the transverse part of the LIPV connected with a single vein, or type 1b, which was defined as the transverse part of the LIPV connected with several veins via anastomoses. Type 2 LIPVs were subclassified into type 2a, in which the LIPV had an undeveloped vertical part; type 2b, in which the LIPV had backflow into systemic veins; or type 2c, in which the LIPV had a connection to the PV. The presence of an anastomosis with the PV was defined as the PV being visualizable on LIPV venography. RESULTS. Assessment of LIPV venography revealed type 1 in 71.5% (153/214) of patients, including type 1a (22.4%, 48/214) and type 1b (49.1%, 105/214). Type 2 LIPVs were observed in 28.5% (61/214) of patients, including types 2a (6.5%, 14/214), 2b (11.2%, 24/214), and 2c (10.7%, 23/214). An anastomosis of the LIPV with the PV was found in 28.0% (60/214) of patients, including 10.7% (23/214) with type 2c and 17.3% (37/214) with type 1 with a visible PV. The anastomoses of the LIPV with the PV were of various sizes. CONCLUSION. The angiographic anatomy of the LIPV varied and was commonly formed from several veins connected by anastomoses. An anastomosis between the LIPV and PV, which might be the origin of gastric varices, was found in 28.0% of patients.

Low diaphragm muscle mass predicts adverse outcome in patients hospitalized for COVID-19 pneumonia: an exploratory pilot study.

BACKGROUND: The aim of this study was to evaluate whether measurement of diaphragm thickness (DT) by ultrasonography may be a clinically useful noninvasive method for identifying patients at risk of adverse outcomes defined as need of invasive mechanical ventilation or death. METHODS: We prospectively enrolled 77 patients with laboratory-confirmed COVID-19 infection admitted to our intermediate care unit in Pisa between March 5 and March 30, 2020, with follow-up until hospital discharge or death. Logistic regression was used identify variables potentially associated with adverse outcomes and those P<0.10 were entered into a multivariate logistic regression model. Cumulative probability for lack of adverse outcomes in patients with or without low baseline diaphragm muscle mass was calculated with the Kaplan-Meier product-limit estimator. RESULTS: The main findings of this study are that: 1) patients who developed adverse outcomes had thinner diaphragm than those who did not (2.0 vs. 2.2 mm, P=0.001); and 2) DT and lymphocyte count were independent significant predictors of adverse outcomes, with end-expiratory DT being the strongest (ß=-708; OR=0.492; P=0.018). CONCLUSIONS: Diaphragmatic ultrasound may be a valid tool to evaluate the risk of respiratory failure. Evaluating the need of mechanical ventilation treatment should be based not only on PaO2/FiO2, but on a more comprehensive assessment including DT because if the lungs become less compliant a thinner diaphragm, albeit free of intrinsic abnormality, may become exhausted, thus contributing to severe respiratory failure.

Lymphatic Pathways of the Thorax: Predictable Patterns of Spread.

OBJECTIVE. This article reviews thoracic lymphatic pathways and tributaries, discusses lymphatic anatomic variants and their clinical implications, and emphasizes common patterns of thoracic lymphadenopathy from extrapulmonary malignancies. CONCLUSION. Recognition of common patterns and pathways of thoracic lymphatic drainage can help identify the site of tumor origin and allow a more focused examination of disease extent, both of which are important for disease prognosis and management.

El diafragma, el hiato y la unión gastroesofágica / The diaphragm, the hiatus and the gastroesophageal junction

RESUMEN La unión del tubo esofágico con el estómago en lo que denominamos el cardias, su tránsito y relacio nes con el hiato diafragmático, las estructuras fibromembranosas que la fijan y envuelven, la existencia de un esfínter gastroesofágico anatómico y su real morfología, así como la interacción de todos estos elementos, han sido materia de controversia por décadas y aún hoy. Este artículo actualiza la descrip ción de tales estructuras.

ABSTRACT The point where the esophagus connects to the stomach, known as the cardia, its transition and re lationship with the diaphragmatic hiatus, its fibromembranous attachments, the existence of an ana tomic gastroesophageal sphincter and its real morphology, and the interaction between all these ele ments, have been subject of debate for decades that still persist. The aim of this article is to describe the updated information of such structures.

Routes of Transdiaphragmatic Migration from the Abdomen to the Chest.

The diaphragm serves as an anatomic border between the abdominal and thoracic cavities. Pathologic conditions traversing the diaphragm are often incompletely described and may be overlooked, resulting in diagnostic delays. Several routes allow abdominal contents or pathologic processes to spread into the thorax, including along normal transphrenic structures, through congenital defects in the diaphragm, through inherent areas of weakness between muscle groups, or by pathways created by tissue destruction, trauma, or iatrogenic injuries. A thorough knowledge of the anatomy of the diaphragm can inform an accurate differential diagnosis. Often, intraperitoneal pathologic conditions crossing the diaphragm may be overlooked if axial imaging is the only approach to this complex region because of the horizontal orientation of much of the diaphragm. Multiplanar capabilities of volumetric CT and MRI provide insight into the pathways where pathologic conditions may traverse this border. Knowledge of these characteristic routes and use of multiplanar imaging are critical for depiction of specific transdiaphragmatic pathologic conditions.©RSNA, 2020.

Laparoscopic fundoplication and new aspects of neural anatomy at the oesophagogastric junction.

BACKGROUND: In fundoplication, mobilization of the distal oesophagus and proximal stomach is essential to obtain a sufficient tension-free intra-abdominal oesophageal length for creation of an efficient antireflux barrier. Most surgical literature and anatomical illustrations do not describe nerve branches running from the diaphragm to the stomach. After observing small nerve branches at laparoscopic fundoplication, penetrating the left crus of the diaphragm lateral to the hiatus and apparently running into the stomach, an anatomical cadaver study was undertaken to identify the origin and target organ of these nerves. METHODS: Fifty-three human cadavers (23 men, 30 women; age range 35-103 years) were dissected with special attention to the nerves that penetrate the left crus of the diaphragm. The entire course of these nerves was documented with standardized drawings and photos. RESULTS: Small nerve branches penetrating the diaphragm lateral to the left crus of the hiatus were found in 17 (32 per cent) of the 53 cadavers. In 14 of these 17 cadavers, one or two splanchnic nerve branches were identified, and in ten of the 17 the nerve branches were found to be phrenic nerves. In seven of these 17 cadavers, two different nerve branches were found and assigned to both splanchnic and phrenic nerves. CONCLUSION: Nerves penetrating the left crus with splanchnic origin or phrenic origin have been identified. Their function remains unclear and their relationship to postfundoplication symptoms remains to be determined.

ANTECEDENTES: A la hora de realizar una fundoplicatura, la movilización del esófago distal y del estómago proximal es esencial para obtener una longitud de esófago intraabdominal suficiente y sin tensión para crear una barrera antirreflujo eficiente. La mayoría de la literatura quirúrgica y de las ilustraciones anatómicas no describen unas ramas nerviosas que discurren desde el diafragma al estómago. Tras observar pequeñas ramas nerviosas durante la realización de una fundoplicatura laparoscópica que penetran la crura izquierda del diafragma lateral al hiato y que aparentemente discurren hacia el estómago, se llevó a cabo un estudio anatómico en cadáver para identificar el origen y el órgano diana de estos nervios. MÉTODOS: Se diseccionaron 53 cadáveres humanos (23 varones, 30 mujeres, rango de edad: 35-103 años) con especial atención hacia los nervios que penetran la crura izquierda del diafragma. Se documentó el recorrido completo de estos nervios con fotos y dibujos de una forma estandarizada. RESULTADOS: En 17 (32%) de 53 cadáveres se hallaron pequeñas ramas nerviosas que penetraban el diafragma lateral a la crura izquierda del hiato. En 14 cadáveres (de los 17) se identificaron una o dos ramas nerviosas esplácnicas, y en 10 de los 17 cadáveres las ramas nerviosas que se hallaron resultaron ser nervios frénicos. En 7 de estos 17 cadáveres, se hallaron dos ramas nerviosas diferentes y se asignaron a ambos nervios, esplácnicos y frénicos. CONCLUSIÓN: Se han identificado los nervios que penetran la crura izquierda con un origen esplácnico y frénico. Sus funciones están por aclarar, así como su relación con los síntomas que aparecen tras la fundoplicatura.

Monitoring diaphragm function in the ICU.

PURPOSE OF REVIEW: To review the clinical problem of diaphragm function in critically ill patients and describes recent advances in bedside monitoring of diaphragm function. RECENT FINDINGS: Diaphragm weakness, a consequence of diaphragm dysfunction and atrophy, is common in the ICU and associated with serious clinical consequences. The use of ultrasound to assess diaphragm structure (thickness, thickening) and mobility (caudal displacement) appears to be feasible and reproducible, but no large-scale 'real-life' study is available. Diaphragm ultrasound can also be used to evaluate diaphragm muscle stiffness by means of shear-wave elastography and strain by means of speckle tracking, both of which are correlated with diaphragm function in healthy. Electrical activity of the diaphragm is correlated with diaphragm function during brief airway occlusion, but the repeatability of these measurements exhibits high within-subject variability. SUMMARY: Mechanical ventilation is involved in the pathogenesis of diaphragm dysfunction, which is associated with severe adverse events. Although ultrasound and diaphragm electrical activity could facilitate monitoring of diaphragm function to deliver diaphragm-protective ventilation, no guidelines concerning the use of these modalities have yet been published. The weaning process, assessment of patient-ventilator synchrony and evaluation of diaphragm function may be the most clinically relevant indications for these techniques.

When and why was the phrenicoabdominal branch of the left phrenic nerve placed into the esophageal hiatus in German textbooks of anatomy? An anatomical study on 400 specimens reevaluating its course through the diaphragm.

BACKGROUND: The phrenicoabdominal branch of the left phrenic nerve passes between muscle fiber bundles within the costal part of the diaphragm near the pericardium. In most German textbooks of anatomy, however, its passage is described to be found in the esophageal hiatus. The aim of this study was to reevaluate its topography relative to the diaphragm in a multicentric study and to identify the initiation of this description. METHODS: In this multicentric study, the most dorsomedial branch of the left phrenic nerve was identified as the phrenicoabdominal branch in 400 embalmed anatomic specimens of Caucasian origin. The distance between its passage and the apex of the pericardium, the left border of the esophageal hiatus, and the inner aspect of the left sixth rib was measured on the cranial aspect of the diaphragm. Textbooks on human anatomy published in German language between 1700 and 2018 were reviewed for their description of the passage of the left phrenicoabdominal branch through the diaphragm. RESULTS: The first statement on the passage of the left phrenicoabdominal branch through the esophageal hiatus was given in 1791 by Sömmering. Since then, in German textbooks of anatomy, a duality in the description of the passage of the left phrenicoabdominal branch persists. In none of the individuals examined in this study, the left phrenicoabdominal branch passed through the esophageal hiatus. In 99.5% of all cases, it pierced the costal part of the diaphragm dorsal to or at the same level as the apex of the pericardium. The mean distances (standard deviations) were 3.4 (±1.5) cm to the apex of the pericardium, 5.8 (±2.2) cm to the esophageal hiatus, and 5.5 (±1.6) cm to the inner aspect of the left sixth rib. CONCLUSION: The findings on the position of the left phrenicoabdominal branch relative to the diaphragm help to improve topographical knowledge and prevent inadvertent nerve injury during surgical interventions on or near the diaphragm. Further to this, these results may form a substantial basis to adopt the correct description of the passage of the left phrenicoabdominal branch to anatomical textbook knowledge.

Relationship between the fall in blood pressure in the standing position and diaphragmatic muscle thickness: proof of concept study.

BACKGROUND: The diaphragm is an important muscle of respiration, and regulates the intrathoracic pressure. Blood pressure is regulated by the baroreceptor reflex system, and is also affected by intrathoracic pressure. We examined the relationship between the diaphragmatic muscle thickness and the degree of drop in blood pressure in the standing position. METHODS: We prospectively studied 15 healthy subjects. The diaphragmatic muscle thickness was measured using a B-mode ultrasonic imaging device. The blood pressure before and after standing was measured by a head-up tilt test. RESULTS: The diastolic blood pressure difference during expiration and inspiration showed a significant correlation with the diaphragmatic muscle thickness (r = 0.578, P = 0.024 and r = 0.518, P = 0.048, respectively). CONCLUSION: The diaphragmatic muscle thickness was related to the fall in diastolic blood pressure in the standing position. This indicates that adequate diaphragmatic muscle thickness helps to maintain intrathoracic pressure and prevents excessive drop in blood pressure in the standing position.

Surgical Anatomy of Paraesophageal Hernias.

Paraesophageal hernia represents a complex surgical problem involving significant distortion of the anatomy and function of the esophagus, stomach, gastroesophageal junction, mediastinum, lungs, and heart. Surgeons operating in the area must have deep understanding of the normal anatomy and pathologic derangements in patients with paraesophageal hernias. This article describes the normal anatomy and anatomic abnormalities in application to the various approaches used in the surgical repair of a paraesophageal hernia.