[Telemonitoring of patients with chronic respiratory failure in France]. / La télésurveillance du patient insuffisant respiratoire chronique en France : l'opportunité d'organiser une prise en charge efficiente.

The year 2023 is marked by the officialization in French law of medical telemonitoring. Adult patients suffering from severe chronic respiratory failure (CRF) and being treated non-invasive ventilation (NIV) and/or oxygen therapy in a home setting are eligible for telemonitoring, of which the costs are to be covered by French health insurance. Telemonitoring allows a medical professional to remotely interpret the data necessary for follow-up and, if necessary, to make decisions regarding management of a given patient. Its objectives are, at the very least, to stabilize the disease through appropriate monitoring, to improve efficiency and quality of care, and to improve that patient's quality of life. The objective of this synthesis is to review the current state of remote monitoring of CRF patients by identifying, through a narrative analysis of the literature, its current benefits and limitations, and to compare present-day telemonitoring with the guidelines of the official French health authority (Haute Autorité de santé) for its nationwide application.

[Genetic polymorphisms and infections]. / Polymorphismes génétiques et infections.

Recent studies have shown that genetic variants, responsible for the different human response when facing an infectious risk, concerned the genes of proteins involved in either recognition of the infectious agent, in the inflammatory cascade, or in the coagulation process. For example, some studies clearly demonstrated that if a twin was affected by an infectious disease, the risk of infection by the same agent for the other twin was significantly higher in homozygote than in heterozygote twins. In Caucasians, a punctual mutation of the TLR2 cytosol was proved to block the response to bacterial lipoproteins and to some Gram positive bacteria and could be responsible for a greater susceptibility to septic shock. Several polymorphisms of the tlr4 gene have been involved in the onset of septic shock in postsurgery infection due to Gram(-) bacilli. Paradoxically, these variants seemed to protect against legionellosis. In pediatrics, polymorphisms of tlr4 were also clearly identified as risk factors for meningococcemia of severe bronchiolitis due to the respiratory syncytial virus (RSV) in children under 2 years of age. A polymorphism of the TLR5 receptor gene, which creates a stop codon and which is responsible for a nonfunctionality of the receptor was associated with the onset of severe legionellosis. Analysing the functions of these genetic polymorphisms in the onset of sepsis will open the way to a lot of research on specific treatments focused on genetic abnormalities.

Reduced exhaled NO is related to impaired nasal potential difference in patients with cystic fibrosis.

Nitric oxide (NO) plays a central role in many airway physiological functions, and its production appears to be related with progression of lung disease in patients with cystic fibrosis (CF). However, underlying mechanisms which specifically link NO and CF-related lung disease remain unclear. Following in vitro and animal studies suggesting a role for NO in ion transport in various epithelia, this work investigates the relationship between transepithelial baseline potential difference (BPD), an index of airway ion transport, and exhaled NO in the airways of adult patients with CF. Association with other phenotypic traits, lung function tests and CFTR genotype was also assessed. Using simple linear regression, F(E)NO and transepithelial BPD values were significantly inversely correlated (p<0.001, r=-0.53). Polynomial analysis evidenced an asymptotic relationship between F(E)NO and BPD values, yielding a plateau for absolute BPD values above 50 mV. This relation was not altered by adjustment for clinical and genetic characteristics of the patients. The relationship between exhaled NO and transepithelial BPD suggests that low NO concentrations likely worsens airway ion transport impairment resulting from CFTR defect. These results fit with experimental studies that suggest the inhibitory effect of NO on sodium absorption, which is the main determinant of airway basal transepithelial conductance.

Nitric oxide synthase 1 as a potential modifier gene of decline in lung function in patients with cystic fibrosis.

BACKGROUND: The severity of lung disease varies widely in patients with cystic fibrosis (CF) who have the same type of mutations of the cystic fibrosis transmembrane regulator (CFTR) gene, suggesting involvement of "modifier" genes. The nitric oxide synthase 1 (NOS1) gene is a candidate for this role because exhaled nitric oxide (NO) is reduced in patients with CF and NOS1 activity contributes to transepithelial ionic transport, immune defence, and non-specific inflammation of the airways. METHODS: Dinucleotide GT repeat polymorphism was studied in the 5' untranslated region of the NOS1 gene, immediately upstream from the transcription initiation site, in 59 patients with CF and 59 healthy controls. RESULTS: Nineteen alleles of the NOS1 gene were identified according to the number of GT repeats (from 18 to 36) in the 5 untranslated region. Exhaled NO levels were significantly correlated with the number of GT repeats. Patients with CF who had the NOS1 genotype associated with high NO production had a slower decline in lung function during the 5 year follow up period. There was no confounding effect of age, chronic bacterial colonisation of the airway, or CFTR genotype. CONCLUSIONS: These data suggest a possible link between the NOS1 gene locus and the rate of decline in lung function in patients with CF.

[Biomechanical study and digital modeling of traction resistance in posterior thoracic implants]. / Etude biomécanique et modélisation numérique de la résistance à la traction des implants thoraciques postérieurs.

PURPOSE OF THE STUDY: The purpose of this experimental study was to compare posterior fixation systems using hooks and screws implanted in the thoracic spine. This study was completed by a digital analysis using the finished element method. MATERIAL AND METHODS: For the experimental study, we used 7 human thoracic spines. Forty-nine groups of 2 vertebrae were individualized. Traction was applied to maximum breaking force measured on an Instron. We used two types of instrumentations, alternating 4 pedicle screws and 2 pedicle-lamina hooks. For the digital study, we used a vertebral model composed of nearly 63 000 nodes and 14 000 elements. Elastic field calculations were carried out with a finished element abacus. RESULTS: The base of the pedicles broke when traction was applied to a pedicle-lamina hook assembly. The medial part of the pedicle broke when traction was applied to a pedicle screw assembly. Maximul break strength for hooks was 1 108 +/- 510 N. It was 820 +/- 418 N for 4 mm diameter screws and 1 395 +/- 435 for 5 mm screws. The most fragile vertebrae were T5-T6 and T7-T8. the screw-instrumented model showed that stress concentrated on the medial aspect of the pedicle, inside the medullary canal. Using a long screw did not reduce the stress force significantly. The hook-instrumented model showed that stress was greatest on the lower part of the pedicle. DISCUSSION: From a mechanical point of view, screw instrumentation is the more appropriate type of fixation. Screw fixation did not however demonstrate its superiority during the traction tests. For 4 mm screws, resistance was 23% weaker than with a hook assembly and for 5 mm screws, it was only 12% stronger. Pullout may be attributed to two principal causes, either fracture of the bony anchoring of the screw system or breakage of the pedicle. Bone thread pullout occurs when the screw threads do not penetrate sufficiently deep into the cortical bone due to the small diameter of the screw shaft. Using a larger diameter screw raises however the problem of damaging the pedicle. Pedicle breakage is seen with stronger stress forces and constitutes the upper limit of maximum break force. This leads us to formulate the hypothesis that in most cases, screw pullout occurs by breakage of the bony threading. Screws are less effective if they are not properly anchored in the pedicles, probably the reason for their relative weakness. Screw diameter should be adapted to the size of each pedicle. This would allow better transmission of stress from the screw to the pedicle. Hooks apply further stress to the vertebrae. The digital study showed that using a long screw crossing through the vertebra does not reduce the stress applied to the pedicles enough to justify its use.

[Metacarpophalangeal prosthesis modeling. Comparison of stress factors in a normal and a prosthetic metacarpophalangeal joint using finite element analysis]. / Modélisation d'une prothèse métacarpophalangienne. Comparaisons de l'état de contraintes par la méthode des éléments finis d'une articulation métacarpophalangienne saine et munie d'une prothèse.

INTRODUCTION: Prosthetic replacement of the metacarpophalangeal joints of long fingers is a problematical technique for the surgeon. The aim of the present study was to examine and compare, by means of finite element analysis, stress distribution in a normal metacarpophalangeal joint and to compare this with the findings in a similar joint with a prosthesis in order to better determine the risk of aseptic loosening, and also to examine possible solutions to limit these risks. METHOD: Finite element modelling was carried out using Abaqus software. Various criteria were taken into account including anatomical data, stress distribution, mechanical characteristics of the materials used, and different positions of the phalanx. RESULTS: A comparison of the results showed two significant stress distribution factors, i.e., a reduction of normal stress in the cortical bone of the finger fitted with a prosthesis; and the appearance of a flexion moment which completely modified the stress distribution throughout the metacarpal and therefore also in the opposite phalanx. DISCUSSION: To reduce the risk of aseptic loosening, two solutions were proposed: a) to reduce Young's module. The problem which arises, as in the case of total hip prosthesis, is that of finding a material with a Young's module which is closer to that of cortical bone, and which at the same time has a high elastic limit and breakage point and good biocompatibility; b) to reduce the inertia of the prosthesis, which seems the more likely of the two propositions, as it is based on the results of the modelling. The inertia of the prosthesis on stress distribution can be reduced by modifying two parameters, namely by producing a hollow section and shortening the structure of the prosthesis.

Blood gas measurement during exercise: a comparative study between arterialized earlobe sampling and direct arterial puncture in adults.

Sampling arterialized earlobe blood is thought to be easier and less painful than direct arterial puncture, and to allow measurement of blood gas values during exercise without the need to insert an arterial cannula. However, arterialized earlobe oxygen tension (PO2) often underestimates arterial PO2 at rest, and is not fully validated during exercise. We have therefore conducted a prospective study to compare values of PO2 and carbon dioxide tension (PCO2) and the discomfort experienced by adult subjects undergoing the two methods of blood sampling during exercise. Seventy consecutive adult patients were studied. Blood samples were drawn simultaneously from the radial artery and arterialized earlobe of each patient during the last minute of an 8 min exercise. Values of PO2 and PCO2 were measured by means of blood gas electrodes. The correlation coefficients between the two samples were 0.92 for PO2 and 0.91 for PCO2. However, the bias and the limits of agreement between the two methods were wide for PO2 (mean+/-2SD of the differences between the two methods: 0.63+/-1.50 kPa (4.7+/-11.2 mmHg)). The bias and the limits of agreement were smaller for PCO2. Patients felt that the earlobe method was not associated with less discomfort than radial artery puncture. We conclude that arterialized earlobe blood oxygen tension is not a good substitute for arterial oxygen tension during exercise, and should not be used to assess arterial oxygen tension in adults during exercise.

[Management of severe amiodarone-induced pneumopathy using inhaled nitric oxide]. / Prise en charge d'une pneumopathie toxique grave à l'amiodarone par le monoxyde d'azote inhalé.

Treatment of amiodarone-induced pulmonary toxicity generally consists in simply discontinuing the drug with subsequent improvement in clinical condition and radiologic abnormalities. Corticosteroid therapy, when used, may accelerate recovery. Early diagnosis is however necessary and mandates the immediate cessation of the drug otherwise diffuse interstitial and alveolar damage can develop and lead to acute respiratory distress syndrome with a high rate mortality. To our knowledge, the use of inhaled nitric oxide to improve arterial oxygenation in amiodarone-induced ARDS has not yet been described. Here we report the case of a patient in whom 2 ppm inhaled nitric oxide in association with mechanical ventilation dramatically improved a life-threatening hypoxemia. We therefore submit that inhaled nitric oxide could be of benefit in patients with amiodarone-induced ARDS.