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High cervical spinal cord injuries induce extreme handicap and tactile isolation. Tracheotomised tetraplegic patients are also bound to be olfaction deprived. By restoring negative pressure inspiration, diaphragm pacing (DP) should improve olfaction. We tested olfaction in 10 consecutive tetraplegics during positive pressure mechanical ventilation and DP, using the University of Pennsylvania Smell Identification Test (UPSIT). Quality of life was assessed using the Satisfaction with Life Scale (SWLS). Self-perceived benefits of DP were studied using an in-house questionnaire. Olfaction was very poor during positive pressure mechanical ventilation (UPSIT, mean+/-SD 17.1+/-6.4, anosmia or severe microsmia). It improved during DP (35.2+/-1.9, normosmia or mild microsmia; p0.0001) and SWLS was 18.5+/-4.2. Nine patients stated that DP had improved their quality of life. This was driven by better mobility (ranked first), improved self-image and relationships with others (ranked second), improved olfaction and better feeling of security (both ranked third). Improved olfaction is among the benefits of DP and should be mentioned to patients considered for this therapy. Furthermore, attention to olfaction is warranted in tracheotomised ventilator-dependent patients, as a putative path towards improvement of quality of life.

Summary Aim: Obstructive sleep apnoeas generate an intense afferent traffic leading to arousal and apnoea termination. Yet a decrease in the sensitivity of the afferents has been described in patients with obstructive sleep apnoea, and could be a determinant of disease severity. How mechanical changes within the respiratory system are processed in the brain can be studied through the analysis of airway occlusion-related respiratory-related evoked potentials. Respiratory-related evoked potentials have been found altered during sleep in mild and moderate obstructive sleep apnoea syndrome, with contradictory results during wake. We hypothesized that respiratory-related evoked potentials’ alterations during wake, if indeed a feature of the obstructive sleep apnoea syndrome, should be present in untreated severe patients. Methods: Ten untreated patients with severe obstructive sleep apnoea syndrome and eight matched controls were studied. Respiratory-related evoked potentials were recorded in Cz-C3 and Cz-C4, and described in terms of the amplitudes and latencies of their components P1, N1, P2 and N2. Results: Components amplitudes were similar in both groups. There was no significant difference in P1 latencies. This was also the case for N1 in Cz-C3. In contrast, N1 latencies in Cz-C4 were significantly longer in patients with obstructive sleep apnoea syndrome [median 98 ms (interquartile range 16·00) versus 79·5 ms (5·98), P = 0·015]. P2 and N2 were also significantly delayed, on both sides. Conclusions: The cortical processing of airway occlusion-related afferents seems abnormal in untreated patients with severe obstructive sleep apnoea syndrome. This could be either a severity marker and/or an aggravating factor.

We hypothesized that (1) in healthy humans subjected to intermittent positive pressure non-invasive ventilation, changes in the ventilator trigger sensitivity would be associated with increased scalene activity, (2) if properly processed - through inspiratory phase-locked averaging - surface electromyograms (EMG) of the scalenes would reliably detect and quantify this, (3) there would be a correlation between dyspnea and scalene EMG. Surface and intramuscular EMG activity of scalene muscles were measured in 10 subjects. They breathed quietly through a face mask for 10min and then were connected to a mechanical ventilator. Recordings were performed during three 15-min epochs where the subjects breathed against an increasingly negative pressure trigger (-5%, -10% and -15% of maximal inspiratory pressure). With increasing values of the inspiratory trigger, inspiratory efforts, dyspnea and the scalene activity increased significantly. The scalene EMG activity level was correlated with the esophageal pressure time product and with dyspnea intensity. Inspiration-adjusted surface EMG averaging could be useful to detect small increases of the scalene muscles activity during mechanical ventilation.

Although several advantages are attributed to tracheotomy in ICU patients requiring mechanical ventilation (MV), true benefits and the optimal timing of tracheotomy remain controversial. In this study, we compared early tracheotomy (ET) with prolonged intubation (PI) in severely ill patients requiring prolonged MV. Prospective, randomized study. Twenty-five medical and surgical ICUs in France. Patients expected to require MV > 7 days. Patients were randomised to either (open or percutaneous) ET within 4 days or PI. The primary end-point was 28-day mortality. Secondary end-points were: the incidence of ICU-acquired pneumonia, number of d1-d28 ventilator-free days, time spent in the ICU, 60-day mortality, number of septic episodes, amount of sedation, comfort and laryngeal and tracheal complications. A sample size of 470 patients was considered necessary to obtain a reduction from 45 to 32% in 28-day mortality. After 30 months, 123 patients had been included (ET = 61, PI = 62) in 25 centres and the study was prematurely closed. All group characteristics were similar upon admission to ICU. No difference was found between the two groups for any of the primary or secondary end-points. Greater comfort was the sole benefit afforded by tracheotomy after subjective self-assessment by patients. The trial did not demonstrate any major benefit of tracheotomy in a general population of ICU patients, as suggested in a previous meta-analysis, but was underpowered to draw any firm conclusions. The potential advantage of ET may be restricted to selected groups of patients.

Upper airway stabilizing muscles play a crucial role in the maintenance of upper airway patency. Transcranial magnetic stimulation allows the investigation of the corticomotor activation process for respiratory muscles. This technique has also been used to evaluate the genioglossus corticomotor response. The aims of this study were to characterize the response of different upper airway stabilizing muscles to focal cortical stimulation of the genioglossus. Alae nasi, genioglossus, levator palatini, palatoglossus and diaphragm motor-evoked potential responses to transcranial magnetic stimulation were recorded during expiration, tidal inspiration and deep inspiration in nine normal awake subjects. A concomitant response of the four studied upper airway muscles was observed in the majority of cortical stimuli. The response of these muscles was independent of the diaphragmatic one that was only occasionally observed. Significant positive relationships were found between alae nasi, levator palatini and palatoglossus motor-evoked potential latencies and amplitudes and the corresponding values of the genioglossus. We conclude that transcranial magnetic stimulation applied in the genioglossus area induces a concomitant motor response of upper airway stabilizing muscles with consistent changes in their motor responses during inspiratory manoeuvres.

Assessing diaphragm function is clinically and physiologically pertinent. It can rely on the measurement of pressure responses to phrenic stimulation. Combining mouth pressure (Pm) with cervical magnetic stimulation (CMS) is painless and easy to perform, but Pm-CMS poorly reflects esophageal pressure (Pes-CMS) because of poor pressure transmission across the airway. We reasoned that the mouth opening and neck flexion that are associated with the measurement of Pm-CMS would impair upper airway dynamics and further hinder pressure transmission. Therefore, we assessed the CMS-related pressure measured in a nasal mask (Pmask; mouth closed) without neck flexion as a possible surrogate of Pes-CMS, in 14 men and 3 women, age 24.5+/-2.2. Pes-CMS was 15.7+/-4.3 cmH2O, significantly higher than Pm-CMS (13.5+/-5.6 cmH2O, P0.0001) but not different from Pmask-CMS (15.2+/-4.9 cmH2O). The concordance correlation coefficient was low (0.6808) between Pes-CMS and Pm-CMS. It was higher between Pes-CMS and Pmask-CMS (0.8730). Pm-CMS wrongly classified five subjects as abnormal (10 cmH2O), versus 1 for Pmask and 5 for Pm (P=0.025). Passing and Bablok regressions found no difference between Pes-CMS and Pmask-CMS, but identified a systematic difference and a proportional error between Pes-CMS and Pm-CMS. We conclude that Pmask-CMS is a better surrogate of Pes-CMS than Pm-CMS.

Resume La commande respiratoire prend sa source dans les reseaux neuronaux du tronc cerebral. Cette commande est transmise a des neurones respiratoires charges de sa distribution aux differents groupes musculaires impliques dans la ventilation : les muscles dilatateurs des voies aeriennes superieures puis les muscles respiratoires du tronc dont la contraction assure la mobilisation de l’air dans les poumons. En tout temps, le generateur central de la commande est renseigne sur l’etat du systeme respiratoire et la resultante de la contraction musculaire en recevant des afferences provenant de mecano- et de chemorecepteurs. De nombreuses situations pathologiques rencontrees en reanimation peuvent modifier directement ou indirectement cette commande et donc la ventilation qui en resulte. De meme, des traitements frequemment mis en œuvre en reanimation (telle la ventilation mecanique) ont aussi une influence sur cette commande. Dans certains cas de trouble ventilatoire mal compris ou en situation de sevrage difficile de la ventilation mecanique, l’exploration du controle de la ventilation peut aider le diagnostic et l’adaptation des therapeutiques. Cette exploration se fonde sur des techniques combinant le recueil de grandeurs ventilatoires en ventilation spontanee et en reponse a des stimulations.

The modulation of activity of the upper airway dilator and respiratory muscles plays a key role in the regulation of ventilation, but little is known about the link between their neuromuscular activation processes in vivo. This study investigated genioglossus and diaphragm responses to transcranial magnetic stimulation applied in different facilitatory conditions. The amplitude and latency of motor-evoked potential responses and the stimulation intensity threshold leading to a motor response (motor threshold) were recorded with stimulation applied at the vertex and anterolateral area in 13 awake normal subjects. Stimuli were applied during inspiration with and without resistance, during expiration with and without maximal tongue protrusion and during deep inspiration. In each stimulation location and condition, no diaphragmatic response was obtained without previous genioglossus activity (diaphragmatic and genioglossus responses latencies during expiration: 18.1 ± 2.9 and 6.3 ± 2.6 ms, respectively, mean ±s.d., P < 0.01). Genioglossus motor-evoked potential amplitude, latency and motor threshold were significantly modified with tongue protrusion with a maximal effect observed for stimulation in the anterolateral area. Deep inspiration was associated with a significant facilitatory effect on both genioglossus and diaphragm motor responses. The facilitatory effects of respiratory and non-respiratory manoeuvres were also observed during focal stimulation where isolated genioglossus responses were observed. Genioglossus and diaphragm differed in their motor threshold both at baseline and following facilitatory manoeuvres. Conclusions: (1) transcranial magnetic stimulation-induced genioglossus response systematically precedes that of diaphragm; (2) this sequence of activation is not modified by respiratory and non-respiratory manoeuvres; and (3) the genioglossus and diaphragm are differently influenced by these manoeuvres in terms of latency of the motor response and of motor threshold.

Human ventilation is aperiodic, exhibiting a breath-by-breath variability and a complexity of which the characteristics may be interesting physiologically and clinically. In the present study, we tested the ability of respiratory inductive plethysmography (RIP) to describe these properties. Indeed, RIP does not have the effects on ventilation described with mouthpiece measurements. We compared the ventilatory flow recorded with a pneumotachograph (V'PNT) and the ventilatory flow derived from the mathematical treatment of the thoracoabdominal motion signals obtained from a particular type of RIP (V'RIP, Visuresp, Meylan, France) in 8 freely breathing normal subjects. Using the Z correlation coefficient, Passing-Bablock regressions and Bland and Altman graphical analyses, we compared the coefficients of variation of the main discrete respiratory variables determined with V'PNT and V'RIP and a set of nonlinear descriptors including the noise limit (chaotic nature of the signal), largest Lyapunov exponent (sensitivity to initial conditions), the Kolmogorov-Sinai entropy (unpredictability) and the correlation dimension (irregularity). When the recordings were obtained with the two techniques simultaneously, all the measurements were correlated and interchangeable. RIP can be safely used to quantify the breath-by-breath variability of ventilation and to study the complexity and the chaotic behavior of the ventilatory flow.

In humans, lung ventilation exhibits breath-to-breath variability and dynamics that are nonlinear, complex, sensitive to initial conditions, unpredictable in the long-term, and chaotic. Hypercapnia, as produced by the inhalation of a CO2-enriched gas mixture, stimulates ventilation. Hypocapnia, as produced by mechanical hyperventilation, depresses ventilation in animals and in humans during sleep, but it does not induce apnea in awake humans. This emphasizes the suprapontine influences on ventilatory control. How cortical and subcortical commands interfere thus depend on the prevailing CO2 levels. However, CO2 also influences the variability and complexity of ventilation. This study was designed to describe how this occurs and to test the hypothesis that CO2 chemoreceptors are important determinants of ventilatory dynamics. Spontaneous ventilatory flow was recorded in eight healthy subjects. Breath-by-breath variability was studied through the coefficient of variation of several ventilatory variables. Chaos was assessed with the noise titration method (noise limit) and characterized with numerical indexes [largest Lyapunov exponent (LLE), sensitivity to initial conditions; Kolmogorov-Sinai entropy (KSE), unpredictability; and correlation dimension (CD), irregularity]. In all subjects, under all conditions, a positive noise limit confirmed chaos. Hypercapnia reduced breathing variability, increased LLE ( P = 0.0338 vs. normocapnia; P = 0.0018 vs. hypocapnia), increased KSE, and slightly reduced CD. Hypocapnia increased variability, decreased LLE and KSE, and reduced CD. These results suggest that chemoreceptors exert a strong influence on ventilatory variability and complexity. However, complexity persists in the quasi-absence of automatic drive. Ventilatory variability and complexity could be determined by the interaction between the respiratory central pattern generator and suprapontine structures.

Faced with mechanical inspiratory loading, awake animals and anaesthetized humans develop alveolar hypoventilation, whereas awake humans do defend ventilation. This points to a suprapontine compensatory mechanism instead of or in addition to the ‘traditional’ brainstem respiratory regulation. This study assesses the role of the cortical pre-motor representation of inspiratory muscles in this behaviour. Ten healthy subjects (age 19–34 years, three men) were studied during quiet breathing, CO2-stimulated breathing, inspiratory resistive loading, inspiratory threshold loading, and during self-paced voluntary sniffs. Pre-triggered ensemble averaging of Cz EEG epochs starting 2.5 s before the onset of inspiration was used to look for pre-motor activity. Pre-motor potentials were present during voluntary sniffs in all subjects (average latency (±s.d.): 1325 ± 521 ms), but also during inspiratory threshold loading (1427 ± 537 ms) and during inspiratory resistive loading (1109 ± 465 ms). Pre-motor potentials were systematically followed by motor potentials during inspiratory loading. Pre-motor potentials were lacking during quiet breathing (except in one case) and during CO2-stimulated breathing (except in two cases). The same pattern was observed during repeated experiments at an interval of several weeks in a subset of three subjects. The behavioural component of inspiratory loading compensation in awake humans could thus depend on higher cortical motor areas. Demonstrating a similar role of the cerebral cortex in the compensation of disease-related inspiratory loads (e.g. asthma attacks) would have important pathophysiological implications: it could for example contribute to explain why sleep is both altered and deleterious in such situations.

Dyspnoea is a prominent symptom of chronic obstructive pulmonary disease (COPD). Recent multidimensional dyspnoea questionnaires like the Multidimensional Dyspnea Profile (MDP) individualise the sensory and affective dimensions of dyspnoea. We tested the MDP in COPD outpatients based on the hypothesis that the importance of the affective dimension of dyspnoea would vary according to clinical characteristics.A multicentre, prospective, observational, real-life study was conducted in 276 patients. MDP data were compared across various categories of patients (modified Medical Research Council (mMRC) dyspnoea score, COPD Assessment Test (CAT) score, Global Initiative for Chronic Obstructive Lung Disease (GOLD) airflow obstruction categories, GOLD “ABCD” categories, and Hospital Anxiety and Depression Scale (HADS)). Univariate and multivariate regressions were conducted to explore factors influencing the affective dimension of dyspnoea. Cluster analysis was conducted to create homogeneous patient profiles.The MDP identified a more marked affective dimension of dyspnoea with more severe mMRC, CAT, 12-item Short-Form Health Survey mental component, airflow obstruction and HADS. Multivariate analysis identified airflow obstruction, depressive symptoms and physical activity as determinants of the affective dimension of dyspnoea. Patients clustered into an “elderly, ex-smoker, severe disease, no rehabilitation” group exhibited the most marked affective dimension of dyspnoea.An affective/emotional dimension of dyspnoea can be identified in routine clinical practice. It can contribute to the phenotypic description of patients. Studies are needed to determine whether targeted therapeutic interventions can be designed and whether they are useful.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease causing diaphragm weakness that can be partially compensated by inspiratory neck muscle recruitment. This disappears during sleep, which is compatible with a cortical contribution to the drive to breathe. We hypothesised that ALS patients with respiratory failure exhibit respiratory-related cortical activity, relieved by noninvasive ventilation (NIV) and related to dyspnoea.We studied 14 ALS patients with respiratory failure. Electroencephalographic recordings (EEGs) and electromyographic recordings of inspiratory neck muscles were performed during spontaneous breathing and NIV. Dyspnoea was evaluated using the Multidimensional Dyspnea Profile.Eight patients exhibited slow EEG negativities preceding inspiration (pre-inspiratory potentials) during spontaneous breathing. Pre-inspiratory potentials were attenuated during NIV (p=0.04). Patients without pre-inspiratory potentials presented more advanced forms of ALS and more severe respiratory impairment, but less severe dyspnoea. Patients with pre-inspiratory potentials had stronger inspiratory neck muscle activation and more severe dyspnoea during spontaneous breathing.ALS-related diaphragm weakness can engage cortical resources to augment the neural drive to breathe. This might reflect a compensatory mechanism, with the intensity of dyspnoea a negative consequence. Disease progression and the corresponding neural loss could abolish this phenomenon. A putative cognitive cost should be investigated.

It has been hypothesized that hyperventilation disorders could be characterized by an abnormal ventilatory control leading to enhanced variability of resting ventilation. The variability of tidal volume (VT) often depicts a nonnormal distribution that can be described by the negative slope characterizing augmented breaths formed by the relationship between the probability density distribution of VT and VT on a log-log scale. The objectives of this study were to describe the variability of resting ventilation [coefficient of variation (CV) of VT and slope], the stability in respiratory control (loop, controller and plant gains characterizing ventilatory-chemoresponsiveness interactions) and the chaotic-like dynamics (embedding dimension, Kappa values characterizing complexity) of resting ventilation in patients with a well-defined dysfunctional breathing pattern characterized by air hunger and constantly decreased PaCO2 during a cardiopulmonary exercise test. Compared with 14 healthy subjects with similar anthropometrics, 23 patients with hyperventilation were characterized by increased variability of resting tidal ventilation (CV of VT median [interquartile]: 26% [19-35] vs. 36% [28–48], P = 0.020; slope: −6.63 [−7.65; −5.36] vs. −3.88 [−5.91; −2.66], P = 0.004) that was not related to increased chemical drive (loop gain: 0.051 [0.039–0.221] vs. 0.044 [0.012–0.087], P = 0.149) but that was related to an increased ventilatory complexity (Kappa values, P < 0.05). Plant gain was decreased in patients and correlated with complexity (with Kappa 5 − degree 5: Rho = −0.48, P = 0.006). In conclusion, well-defined patients suffering from hyperventilation disorder are characterized by increased variability of their resting ventilation due to increased ventilatory complexity with stable ventilatory-chemoresponsiveness interactions.

Poor sleep is common in intensive care unit (ICU) patients. However, the risk factors and the consequences of sleep abnormalities on the outcome are not well established. This all the more true that many studies have not been based on polysomnography and have been conducted in patients receiving sedation.

Sepsis and mechanical ventilation are both risk factors of diaphragmatic dysfunction (DD) in critically ill patients. The evolution of diaphragmatic function under mechanical ventilation in septic and non-septic patients has not been described.

International audience; In awake humans, breathing depends on automatic brainstem pattern generators. It is also heavily influenced by cortical networks. For example, functional magnetic resonance imaging and electroencephalographic data show that the supplementary motor area becomes active when breathing is made difficult by inspiratory mechanical loads like resistances or threshold valves, which is associated with perceived respiratory discomfort. We hypothesized that manipulating the excitability of the supplementary motor area with repetitive transcranial magnetic stimulation would modify the breathing pattern response to an experimental inspiratory load and possibly respiratory discomfort. Seven subjects (three men, age 25 ± 4) were studied. Breathing pattern and respiratory discomfort during inspiratory loading were described before and after conditioning the supplementary motor area with repetitive stimulation, using an excitatory paradigm (5 Hz stimulation), an inhibitory paradigm, or sham stimulation. No significant change in breathing pattern during loading was observed after sham conditioning. Excitatory conditioning shortened inspiratory time (p = 0.001), decreased tidal volume (p = 0.016), and decreased ventilation (p = 0.003), as corroborated by an increased end-tidal expired carbon dioxide (p = 0.013). Inhibitory conditioning did not affect ventilation, but lengthened expiratory time (p = 0.031). Respiratory discomfort was mild under baseline conditions, and unchanged after conditioning of the supplementary motor area. This is the first study to show that repetitive transcranial magnetic stimulation conditioning of the cerebral cortex can alter breathing pattern. A 5 Hz conditioning protocol, known to enhance corticophrenic excitability, can reduce the amount of hyperventilation induced by inspiratory threshold loading. Further studies are needed to determine whether and under what circumstances rTMS can have an effect on dyspnoea.

The respiratory behaviour in humans is exquisitely sensitive to measurements involving any sort of constraint placed on the respiratory system. The use of a mouthpiece to measure ventilatory flow with a pneumotachograph (PNT) introduces a major perturbation to breathing ("un-gating" effect) and therefore constitutes a stimulus that modifies the respiratory behaviour. Structured light plethysmography (SLP) is a non-contact method of assessment of breathing pattern during tidal breathing. We compared SLP measurement (Thora-3Di™, PneumaCare, UK) to SLP+PNT measurement to evaluate the disruption in breathing pattern during tidal breathing in COPD patients when adding a PNT. Measurements were taken during tidal breathing with SLP recording alone and with SLP+PNT recording in 41 COPD patients (FEV1=58±21%predicted). The thoracic contribution to tidal breathing (T), the time to peak tidal expiratory flow over expiratory time (TPTEF/TE, a measure of airways obstruction and flow-limitation during tidal breathing), and the time to peak tidal inspiratory flow over inspiratory time (TPTIF/TI, a measure of inspiratory flow reserve during tidal breathing) were measured. Compared with SLP only, the following variables changed significantly during SLP+PNT recording: T=47±12 vs 45±13% (p=0.045), TPTEF/TE=0.27±0.10 vs 0.24±0.08 (p=0.018), TPTIF/TI=0.50±0.09 vs 0.53±0.07 (p=0.017). When adding a PNT compared to SLP alone, tidal breathing pattern was disrupted in COPD patients. SLP is a novel and promising approach for evaluating resting quiet tidal breathing that avoids any modifications in breathing pattern induced by a mouthpiece and PNT.

Rational: Mechanical ventilation decreases the natural variability of major descriptors of the breathing pattern such as tidal volume (VT), inspiratory time (Ti), respiratory rate (RR) and mean inspiratory flow (Vt/Ti). Few studies have investigated the risk factors and the impact of a decreased variability on the outcome. Study aims: to identify risk factors of decreased breathing variability,to describe the consequences of a decreased breathing variability on the outcome. Methods: Ancillary study of a randomized controlled trial comparing neurally ventilator adjusted assist to pressure support ventilation in 127 patients. VT, RR and Vt/Ti were computed from the flow signal recordings and their respective coefficients of variation (CV) were calculated. Subjects were classified as having high or low variability pattern according to a cut-off determined by the respective median of each CV. Results: Mean coefficient of variation for RR, VT, VT/Ti was respectively 0.22 ± 0.09, 0.21 ± 0.10 and 0.17 ± 0,12. Age was significantly lower in patients with a high CV for RR compared to those with a low CV (65±13 vs.70±11, p= 0.038). No other significant difference was observed in term of gender, severity score (SAPS II), dyspnea, comfort and mechanical ventilation duration before inclusion between patients with a high or low CV. No significant difference was found between patients with high and low variability in term of on D28 mortality, duration of mechanical ventilation and length of stay. Conclusion: Among all factors, only age was associated with a decrease of breathing variability. Decrease of breathing variability was not associated with an alteration of the outcome.

Introduction: When pleural procedures (PP) are required in patients receiving antiplatelet therapy (APT), the risk of bleeding with APT continuation must be balanced against the risk of arterial thrombosis with APT withdrawal. Currently, the bleeding risk of PP in patients with APT is unknown. Objectives: The study aimed at assessing the incidence of bleeding events (BE) after PP in patients receiving APT in comparison with controls. Methods: A prospective multicentric study was conducted in 18 respiratory care departments and 11 medical intensive care units. The occurrence of BE was considered within the 24 hours following PP performance. Results: 1133 PP were recorded: 130 (12%) blind pleural biopsies, 625 (55%) chest tube insertions, 378 (33%) thoracocentesis in 185 APT+ and 948 APT- subjects. APT+ subjects were more frequently males (89% vs 64%; p=0.02) and were older (73±13 vs 58±19 years; p In the APT+ group, there was a higher prevalence of renal failure (42% vs 23%; p Conclusion: In this study, APT was associated with a 3 folds increase in PP-related bleeding risk.

Background: Diaphragm dysfunction (DD) is a major concern in intensive care unit (ICU) patients. The gold standard method to diagnose DD is the measure of intra-thoracic pressure in response to a bilateral stimulation of the phrenic nerve (Ptr,stim). This technique is costly, requires expertise and is not widely available. Diaphragm ultrasound (US) could be an interesting alternative. Objectives: To assess the time course of diaphragm function simultaneously with Ptr,stim and US, and to compare US to Ptr,stim to detect DD. Methods: Monocentric prospective study in a medical ICU. DD was detected at three key time points: 1) during the first 24h of controlled ventilation (CV), 2) as soon as patients could tolerate pressure support ventilation (PSV) and 3) before the first spontaneous breathing trial (SBT). Ptr,stimwas measured using bilateral anterior magnetic stimulation and the thickening fraction (TF) of the diaphragm was obtained from M-mode US. A Ptr,stim< -11 cmH2O defined DD. Results: Forty-three critically ill patients were investigated (77 measurements). DD was present in 79%, 85% and 58% of patients during CV, PSV and SBT respectively. The respective mean Ptr,stim were 8.1±4, 7.5±4 and 11.8±6 cm H2O (p=0.02 for CV vs. SBT). There was a significant correlation between Ptr,stim and TF during PSV and SBT (R2=0.88, p

Rational: Patient-ventilator asynchrony (PVA) is a mismatch between patient and ventilator times during mechanical ventilation (MV). The few studies that have investigated their impact have suggested that high prevalence of asynchronies is associated with prolonged duration of MV. Study aims: to quantify prevalence of PVA by electromyographic activity of the diaphragm (Edi), identify risk factors for PVA, describe their consequences on the outcome. Methods: Ancillary study of a randomized controlled trial comparing neurally ventilator adjusted assist to pressure support ventilation in 127 patients. Asynchronies were quantified at H12, 24, 36 and 48 on recordings of flow, airway pressure and Edi. Asynchrony index (AI) was defined as number of asynchrony events/total respiratory rate x100. Severe asynchrony was defined as an AI >20%. Results: Median AI was 24 (0-69). Prolonged and short cycles were the main asynchronies (respectively 37% and 31% of asynchronies) followed by double-triggering (21%). No significant difference was observed in term of age, SAPS II, gender, dyspnea, comfort scale, ATICE between patients with an AI >20% and those with an AI Conclusion: Based on Edi recording, prevalence of PVA is high. Among all factors, none was associated with an increased PVA. Increased patient-ventilator asynchrony at H12 was associated with prolonged duration of mechanical ventilation and length of stay.

The effects of bronchodilators (BD) are traditionally assessed using forced expiratory maneuvers. Real-life evaluation of BD is desirable. Structured light plethysmography (SLP) is a non-contact, non-invasive method of assessment of breathing pattern during tidal breathing. We used a Thora-3Di ™ (PneumaCare, UK) to evaluate the BD effects on breathing pattern during tidal breathing in COPD patients. Measurements were taken during tidal breathing, pre and post administration of short-acting BD in 41 COPD patients (31M, 65±8yrs, mean post-BD FEV1=63±23%predicted). Breath Phase (BP, the phase difference between thorax and abdomen as measured using the Konno-Mead X-Y plot, a measure of thoraco-abdominal asynchrony), the inspiratory and expiratory phases (IP and EP respectively, two different measures of asynchrony between thorax and abdomen), time to peak tidal expiratory flow over expiratory time (TPTEF/TE, a measure of airways obstruction and flow-limitation), inspiratory capacity (IC) and dyspnoea (visual analog scale, VAS) were measured. In the 29 patients who showed an increase in post-BD IC>130mL, the following variables changed significantly (p

Background: Dyspnea, like pain, can cause major suffering in intensive care unit (ICU) patients. Its evaluation relies on self-report; hence, the risk of being overlooked when verbal communication is impaired. Observation scales incorporating respiratory and behavioral signs (respiratory distress observation scales [RDOS]) can provide surrogates of dyspnea self-report in similar clinical contexts (palliative care). Methods: The authors prospectively studied (single center, 16-bed ICU, large university hospital) 220 communicating ICU patients (derivation cohort, 120 patients; separate validation cohort, 100 patients). Dyspnea was assessed by dyspnea visual analog scale (D-VAS) and RDOS calculated from its eight components (heart rate, respiratory rate, nonpurposeful movements, neck muscle use during inspiration, abdominal paradox, end-expiratory grunting, nasal flaring, and facial expression of fear). An iterative principal component analysis and partial least square regression process aimed at identifying an optimized D-VAS correlate (intensive care RDOS [IC-RDOS]). Results: In the derivation cohort, RDOS significantly correlated with D-VAS (r = 0.43; 95% CI, 0.29 to 0.58). A five-item IC-RDOS (heart rate, neck muscle use during inspiration, abdominal paradox, facial expression of fear, and supplemental oxygen) significantly better correlated with D-VAS (r = 0.61; 95% CI, 0.50 to 0.72). The median area under the receiver operating curve of IC-RDOS to predict D-VAS was 0.83 (interquartile range, 0.81 to 0.84). An IC-RDOS of 2.4 predicted D-VAS of 4 or greater with equal sensitivity and specificity (72%); an IC-RDOS of 6.3 predicted D-VAS of 4 or greater with 100% specificity. Similar results were found in the validation cohort. Conclusions: Combinations of observable signs correlate with dyspnea in communicating ICU patients. Future studies in noncommunicating patients will be needed to determine the responsiveness to therapeutic interventions and clinical usefulness.

Background Long acting bronchodilators are the standard of care in the management of chronic obstructive pulmonary disease (COPD). The aim of this study was to investigate the efficacy and safety of V0162, a novel anticholinergic agent with bronchodilator properties, in preclinical models and in patients with COPD. Methods Guinea pigs were used to evaluate the impact of V0162 on the acetylcholine or histamine-induced bronchoconstriction. V0162 was also investigated in an allergic asthma model on ovalbumin-sensitized guinea pig. For clinical investigations, healthy volunteers were included in a dose-escalation, randomized, placebo-controlled phase I study to determine the maximal tolerated dose, followed by a randomized, placebo-controlled, cross-over phase II study in patients with COPD. V0162 was given via inhalation route. The objectives of the phase I/II study were to assess the safety and efficacy of V0162, in terms of bronchodilation and reduction in hyperinflation. Results Preclinical results showed that V0162 was able to prevent bronchoconstriction induced either by acetylcholine or histamine. V0162 reversed the bronchoconstriction and airway inflammation caused by ovalbumin challenge in sensitized guinea pigs. In the healthy volunteers study, 88 subjects were enrolled: 66 received V0162 and 22 received placebo. No particular safety concerns were raised. The maximal tolerated dose was not reached and the dose escalation was stopped at 2400 μg. A total of 20 patients with COPD were then enrolled. All patients received a single-dose of V0162 1600 μg and of placebo in two alternating periods. In COPD patients, V0162 demonstrated a significant increase in FEV1 compared with placebo (148 ± 137 ml vs. 36 ± 151 ml, p = 0.003). This bronchodilatory effect was corroborated by a reduction in hyperinflation. There was a trend toward dyspnea relief (change in visual analog scale at 22 h, −15.1 ± 26.0 mm vs.- 5.3 ± 28.8 mm with placebo, p = 0.054). No serious adverse events (AEs) were reported. Most common AEs were productive and non-productive cough, dyspnea and pruritus. Conclusions V0162 improved pulmonary function and tended to improve dyspnea in patients with COPD over more than 24 h. The slight plasmatic exposure observed might support the good safety profile. Trial registration ClinicalTrials.gov identifier: NCT01348555

s / Brain Stimulation 8 (2015) 412e427 420 long term memory and Cluster 3 by more prominent visual-spatial and executive dysfunction. Neurophysiological evaluation showed that Cluster 2 was characterized by a reversal of LTP towards LTD and by more affected cholinergic transmission when compared with other clusters. These results suggest that AD is a heterogeneous condition characterized by different mechanisms of synaptic transmission associated with specific patterns of CSF biomarkers.

Introduction The objective was to compare the impact of three assistance levels of different modes of mechanical ventilation; neurally adjusted ventilatory assist (NAVA), proportional assist ventilation (PAV), and pressure support ventilation (PSV) on major features of patient-ventilator interaction. Methods PSV, NAVA, and PAV were set to obtain a tidal volume (VT) of 6 to 8 ml/kg (PSV100, NAVA100, and PAV100) in 16 intubated patients. Assistance was further decreased by 50% (PSV50, NAVA50, and PAV50) and then increased by 50% (PSV150, NAVA150, and PAV150) with all modes. The three modes were randomly applied. Airway flow and pressure, electrical activity of the diaphragm (EAdi), and blood gases were measured. VT, peak EAdi, coefficient of variation of VT and EAdi, and the prevalence of the main patient-ventilator asynchronies were calculated. Results PAV and NAVA prevented the increase of VT with high levels of assistance (median 7.4 (interquartile range (IQR) 5.7 to 10.1) ml/kg and 7.4 (IQR, 5.9 to 10.5) ml/kg with PAV150 and NAVA150 versus 10.9 (IQR, 8.9 to 12.0) ml/kg with PSV150, P 100 and level150. The coefficient of variation of VT was higher with NAVA and PAV (19 (IQR, 14 to 31)% and 21 (IQR 16 to 29)% with NAVA100 and PAV100 versus 13 (IQR 11 to 18)% with PSV100, P P P Conclusions PAV and NAVA both prevent overdistention, improve neuromechanical coupling, restore the variability of the breathing pattern, and decrease patient-ventilator asynchrony in fairly similar ways compared with PSV. Further studies are needed to evaluate the possible clinical benefits of NAVA and PAV on clinical outcomes. Trial registration Clinicaltrials.gov NCT02056093. Registered 18 December 2013.

Study objectives The obstructive sleep apnea syndrome (OSAS) involves recurrent sleep-related upper airways (UA) collapse. UA mechanical properties and neural control are altered, imposing a mechanical load on inspiration. UA collapse does not occur during wakefulness, hence arousal-dependent compensation. Experimental inspiratory loading in normal subjects elicits respiratory-related cortical activity. The objective of this study was to test whether awake OSAS patients would exhibit a similar cortical activity. Design Descriptive physiology study. Setting Sleep laboratory in a large university affiliated tertiary hospital. Patients 26 patients with moderate OSAS according to polysomnography (5 30, n = 12); 13 non-OSAS patients for comparison. Interventions None. Measurements Respiratory time-locked electroencephalographic segments ensemble averaged and analyzed for slow premotor potentials preceding inspiration ("pre-inspiratory potentials" [PIPs]). Results PIPs were present in 1/13 controls and 11/26 patients (P = 0.0336; 4/14 "moderate" and 7/12 "severe" patients). Awake OSAS patients therefore exhibit respiratory-related cortical activity during quiet breathing significantly more frequently than non-OSAS individuals. The corresponding PIPs resemble those observed during prepared voluntary inspirations and in response to experimental inspiratory loads in normal subjects, which involve a cortical network comprising the supplementary motor area. Conclusions A respiratory-related cortical activity could contribute to the increased neural drive to upper airway and to inspiratory muscles that has previously been described in obstructive sleep apnea, and could therefore contribute to the arousal-dependent compensation of upper airway abnormalities. Whether or not such cortical compensatory mechanisms have cognitive consequences remains to be determined.

International audience; OBJECTIVETo predict the outcome of a spontaneous breathing trial (SBT) through the ultrasonographic assessment of diaphragmatic and intercostal muscle function.MethodsMechanically ventilated patients from a 16-bed medical intensive care unit (ICU) were prospectively included before starting an SBT. Diaphragmatic function was estimated by the intrathoracic depression induced by anterior magnetic phrenic stimulation (Ptr,stim) and by performing an ultrasonography of the right hemidiaphragm. Intercostal muscle function was assessed using ultrasonography of the second right anterior intercostal space. We measured expiratory and peak inspiratory muscle thickness (Tde and Tdi respectively) and muscle thickening fraction (TFD and TFIC for diaphragm and intercostal), defined as (Tdi - Tde)/Tdi.The Medical Research Council (MRC) Score was also used to detect peripheral muscle weakness.Successful weaning (SW) was defined by extubation after SBT without reintubation in the following 48 hours and weaning failure (WF) by a failed SBT or a reintubation in the 48 hours after extubation. DD was defined by a value of Ptr,stim of less than -11 cmH2O.ResultsForty patients were included (age 55 ± 18): 27 and 13 patients in the SW and WF group respectively. Mean SOFA score was 5 ± 3 and length of mechanical ventilation the day of the SBT was 7 ± 3 days.Compared to SW patients, WF patients had lower Ptr,stim (6.1 ± 0.7 vs 13.6 ± 1.2 cmH2O p < 0.001), lower TFD (21.2 ± 6 vs 35.6 ± 13% p < 0.01), lower MRC score (40.3 vs 55.7, p < 0.01) and higher TFIC (26.7 ± 15 vs 10.4 ± 6%, p < 0.01). Areas under the receiver operating characteristics curves to predict WF were 0.86, 0.84, 0.88 and 0.88 for Ptr,stim, TFD, MRC score and TFIC respectively (all p < 0.05). The best Ptr,stim and TFD thresholds to predict WF were 8.2 cm H2O and 29%, respectively.Ptr,stim was significantly correlated with TFd, MRC score and TFic (rho = 0.88, 0.55 and -0.90 respectively).Among patients with DD, only 46% were successfully separated from the ventilator whereas all patients without DD were successfully separated from the ventilator (p < 0.001).ConclusionsPtr,stim, TFD, MRC and TFIC are strong predictors of weaning outcome.Our findings support the hypothesis that diaphragmatic dysfunction is significantly, although not systematically, associated with weaning failure.

International audience; Background: Congenital central hypoventilation syndrome (CCHS) is a rare genetic disease due to PHOX2B mutations. CCHS patients suffer from many autonomic disorders, dominated clinically by defective ventilatory automatisms. From birth, the life of CCHS patients depends on ventilatory support during sleep, involving a high burden of care. Whether or not this impairs the quality of life of these patients during adulthood remains unknown. Methods: We applied the medical outcome study short form-36 (SF-36) to 12 CCHS patients aged 15–33 (9 women) at the time of their passage from pediatric to adult care. Scores for the SF-36 dimensions were compared to the age-and gender-matched French reference population after transformation into standardized Z-scores. The SF-36 physical component summary score (PCS) and mental component summary score (MCS) were compared to American reference values. Results: Median Z-scores were significantly different from zero for PF (physical functioning, p = 0.020) and GH (general health perception, p = 0.0342) and for PCS (p = 0.020). The other physical dimensions (RP, role limitation due to physical function; BP, bodily pain) and the mental dimensions (VT, vitality; SF, social functioning; RE, role limitation due to emotional function; MH, mental health) and MCS were not altered. Conclusions: We conclude that, despite the physical constraints imposed by CCHS and its anxiogenic nature, this disease is associated with an impairment of health-related quality of life in young adults that remains moderate. Whatever the underlying explanations, these results convey hope to parents with a child diagnosed with CCHS and for patients themselves.

International audience; Steady state visual evoked potentials (SSVEP)have been widely utilized in brain computer interfacing (BCI)in last years. In this paper, we present a study exploringthe possibilities of SSVEP to manage the communicationbetween patients suffering respiratory disorders and healthcare providers. By imposing different breathing constraints,five healthy subjects communicated their breathing sensations(breathing well/breathing bad) using a visual frequency taggingparadigm: two visual stimuli with different flickeringfrequencies (15 and 20 Hz) were simultaneously presented ona screen. Using electroencephalographic (EEG) signals fromonly three EEG electrodes, two spectral features were extractedby a spatial filter in a sliding window, then classified by anunsupervised algorithm based on k-medians. Average detectionsuccess rates were of 70% during breathing discomfort, andof 83% when subjects breathed comfortably. Results suggestthat SSVEP-based BCI may be a promising choice to improvepatient-caregiver communication in situations of breathingdiscomfort when verbal communication is difficult

The human ventilation depends on bulbospinal and corticospinal commands. This study assessed their interactions in five healthy volunteers (two men, age 25-35) through the description of diaphragm and abductor pollicis brevis (APB) motor potentials (DiMEPs, abpMEPs) evoked by transcranial magnetic stimulation (TMS) during relaxed expiration and tidal inspiration and during wake and sleep. NREM decreased corticospinal excitability and REM further did so, for both the diaphragm and the APB. During wake, inspiration shortened supine DiMEPs latencies (expiration 18.56+/-1.90ms; inspiration 17.37+/-1.48ms, P0.001). This persisted during sleep in an augmented manner (expiration: 21.05+/-1.39ms; inspiration 18.69+/-1.17ms, P=0.002). Inspiration had no effect on apbMEPs during wake and sleep.(1) the tidal bulbospinal input to phrenic motoneurones is sufficient to modulate the throughput of the corticospinal pathway to these neurones; (2) this modulation is best seen after the sleep related removal of corticospinal and/or afferent inputs.

To evaluate the efficacy of a simple mechanical device to maintain constant endotracheal cuff pressure (Pcuff) during mechanical ventilation (large encased inflatable cuff connected to the endotracheal cuff and receiving constant pressure from a heavy mass attached to an articulated arm).Single-center, prospective, randomized, crossover, pilot study in a medical intensive care unit.Nine consecutive mechanically ventilated patients (age 62+/-20 years, SAPS II score 39+/-15).Control day: Pcuff monitored and adjusted with a manometer (Hi-Lo, Tyco Healthcare) according to current recommendations (twice a day and after each intervention on the tracheal tube); initial target Pcuff 22-28 cmH20. Prototype day: test device connected to the endotracheal cuff; same initial target. Continuous Pcuff recording during both days. Control and prototype days in random order.Pcuff values over 50 cmH20 were recorded in six patients during the control day (178+/-159min), never during the prototype day. During the control day, Pcuff was between 30 and 50 cmH20 for 29+/-25% of the time, vs 0.3+/-0.3% during the prototype day (p0.01). Pcuff was between 15 and 30 cmH20 for 56+/-36% of the time during the control day, vs 95+/-14% during the prototype day p0.01). During the control day, Pcuff was below 15 cmH20 for 15+/-17% of the time, vs 4.7+/-15% during the prototype day (p0.05).The tested device successfully controlled Pcuff with minimal human resource consumption. Prospective studies are required to assess its clinical impact.

The mammalian ventilatory behavior exhibits nonlinear dynamics as reflected by certain nonlinearity or complexity indicators (e.g. correlation dimension, approximate entropy, Lyapunov exponents...) but this is not sufficient to determine its possible chaotic nature. To address this, we applied the noise titration technique, previously shown to discern and quantify chaos in short and noisy time series, to ventilatory flow recordings obtained in quietly breathing normal humans. Nine subjects (8 men and 1 woman, 24-42 yrs) were studied during 15-minute epochs of ventilatory steady-state (10.1 +/- 3.0 breaths/minute, tidal volume 0.63 +/- 0.2L). Noise titration applied to the unfiltered signals subsampled at 5 Hz detected nonlinearity in all cases (noise limit 20.2 +/- 12.5%). Noise limit values were weakly correlated to the correlation dimension and the largest Lyapunov exponent of the signals. This study shows that the noise titration approach evidences a chaotic dimension to the behavior of ventilatory flow over time in normal humans during tidal breathing., 24 pages, 3 figures, presented at 27th Annual International Conference of the IEEE Engineering in Medicine and Biology Society

Objective: To assess the value of the diaphragmatic response to transcranial magnetic stimulation (TMS) in predicting the recovery of ventilatory activity after CNS lesions responsible for central respiratory paralysis. Methods: The authors studied 11 long-term ventilator-dependent patients with central respiratory paralysis (description group: spinal trauma 10, medullary ischemia 1) and 16 patients with central respiratory paralysis for less than 10 weeks (prognostic group, evaluated after a 1-year follow-up: spinal trauma 8, medullary ischemia 4, radiation myelitis 1, subdural hematoma 1, complication of neurosurgery 2). Results: In the description group, all the patients had a bilaterally abolished diaphragm response. In the prognostic group, six patients were fully ventilator dependent because of a complete absence of ventilatory activity at follow-up time. They lacked any diaphragm response. The 10 other patients had recovered ventilatory activity and full (n = 9) or partial (n = 1) ventilatory autonomy. In nine cases, diaphragm response was present at least on one side, with a normal latency (right: 15.6 ± 1.5 milliseconds; left: 16.2 ± 2.2 milliseconds). The test had 100% specificity (95% CI 52 to 100) and 90% sensitivity (95% CI 54 to 99) to predict the recovery of ventilatory activity. Conclusion: Electrophysiologic studies of the diaphragm in response to transcranial magnetic stimulation may help predict the recovery of central respiratory paralysis within 1 year.

Resume La ventilation est une activite cyclique continue durant laquelle se succedent des phases inspiratoires et des phases expiratoires. Cette activite n'est pas monotone et la diversite, ou variabilite, des cycles respiratoires n'est probablement pas fortuite. Une maniere d'apprehender la complexite du controle de la ventilation pourrait etre d'etudier la variabilite dans le temps des grandeurs de sortie du « generateur ». Outre l'approche physiopathologique, un certain nombre d'etudes preliminaires montrent l'interet d'analyser la variabilite de la ventilation dans certaines conditions pathologiques. Ainsi, en reanimation la baisse de la variabilite de la ventilation pourrait etre un marqueur predictif de l'echec de l'extubation. Enfin, l'utilisation d'une assistance ventilatoire variable semble pouvoir ameliorer l'oxygenation des malades presentant une hypoxemie postoperatoire.

Anaemia of chronic disease (ACD), with chronically low levels of circulating haemoglobin, is an immune driven abnormality that occurs in many inflammatory diseases, and also in chronic heart failure. Although chronic obstructive pulmonary disease (COPD) is "traditionally" associated with polycythaemia, the systemic inflammation that is now recognised as a feature of COPD makes it a possible cause of ACD. If present in COPD, anaemia could worsen dyspnoea and limit exercise tolerance. Preliminary evidence suggests that anaemia in COPD patients may be more prevalent than expected, concerning 10-15% of patients suffering from severe forms of the disease. A database study conducted in 2,524 COPD patients being prescribed long-term oxygen therapy has shown that a low haematocrit is a strong predictor of survival in this population, before body mass index, and is associated with more hospitalisations and a longer cumulative duration of hospitalisation. COPD patients with low haemoglobin levels have a poorer prognosis than COPD patients with normal haemoglobin levels in the event of acute gastrointestinal bleeding or after elective aneurysm repair. Raising haemoglobinaemia through transfusion decreases minute ventilation and work of breathing in COPD patients. These preliminary evidences point to the need to study the prevalence of anaemia, and its physiological and clinical impact in chronic obstructive pulmonary disease. When this body of knowledge is available, the question of the putative benefits of raising haemoglobinaemia in chronic obstructive pulmonary disease will have to be addressed.

Studying the inspiratory recruitment of the scalenes is clinically relevant, but the interpretation of surface electromyographic (EMG) recordings is difficult. The aim of this study was to optimize an averaging method to analyze the surface EMG activity of the scalenes. Ten healthy subjects were studied. Nasal flow and surface EMG of the right scalene were recorded during 15 min epochs of quiet breathing. In four subjects, needle scalene EMG was also recorded. The flow signal was used to trigger the ensemble averaging of the ventilatory wave forms from 80 consecutive breaths. In eight cases, this evidenced a phasic inspiratory activation of the scalenes and permitted the determination of the electromechanical inspiratory delay (134+/-55 ms) and post-inspiratory activity (811+/-233 ms). When simultaneously available, surface and intramuscular recordings provided identical results. An averaging method triggered from a respiratory flow signal can identify and characterize a low phasic inspiratory activity of the scalenes within a noisy surface signal.

and the European Central Hypoventilation Syndrome Consortium; International audience; Central hypoventilation syndromes (CHS) are rare diseases of central autonomic respiratory control associated with autonomous nervous dysfunction. Severe central hypoventilation is the hallmark and the most life-threatening feature. CHS is a group of not-fully defined disorders. Congenital CHS (CCHS) (ORPHA661) is clinically and genetically well-characterized, with the disease-causing gene identified in 2003. CCHS presents at birth in most cases, and associated with Hirschsprung’s disease (ORPHA99803) and neural crest tumours in 20% and 5% of cases, respectively. The incidence of CCHS is estimated to be 1 of 200,000 live births in France, yet remains unknown for the rest of the world. In contrast, late-onset CHS includes a group of not yet fully delineated diseases. Overlap with CCHS is likely, as a subset of patients harbours PHOX2B mutations. Another subset of patients present with associated hypothalamic dysfunction. The number of these patients is unknown (less than 60 cases reported worldwide). Treatment of CHS is palliative using advanced techniques of ventilation support during lifetime. Research is ongoing to better understand physiopathological mechanisms and identify potential treatment pathways.The Fourth International Conference on Central Hypoventilation was organised in Warsaw, Poland, April 13–15, 2012, under the patronage of the European Agency for Health and Consumers and Public Health European Agency of European Community. The conference provided a state-of-the-art update of knowledge on all the genetic, molecular, cellular, and clinical aspects of these rare diseases.

Cortical potentials evoked by mid-inspiratory occlusion arise from numerous receptors, many of which are probably within the upper airway. Their precise nature is not known. The aim of the current study was to improve knowledge of this by studying the effects of topical upper airway anaesthesia on respiratory-related evoked potentials. Respiratory-related evoked potentials were described through the averaging of electroencephalogram (EEG) epochs following mid-inspiratory occlusions (C 3 –C Z ; C 4 –C Z ). A total of 21 healthy volunteers (13 male, aged 22–52 yrs) were studied during mouth breathing, before and after topical upper airway anaesthesia (lidocaine). Moreover, 15 subjects were studied during nose breathing with and without anaesthesia. Six subjects were studied whilst inhaling L-menthol. Typical potentials were present in all the subjects, their components featuring normal amplitudes and latencies. The route of breathing and upper airway anaesthesia did not modify the EEG responses to inspiratory occlusions, qualitatively or quantitatively, during mouth or nose breathing. L-menthol had no effect. Upper airway receptors sensitive to topical anaesthesia are unlikely to contribute significantly to mid-inspiratory occlusion-evoked potentials. On the contrary, deeper receptors, such as joint and muscle receptors, could contribute dominantly to these potentials.

Resume Position du probleme La ventilation par tracheotomie est efficace chez des patients atteints de maladies neuromusculaires, mais contraignante. Le « retour » a une ventilation au masque (VNI) peut etre envisage, mais cette pratique n’est pas repandue, en partie faute de procedures standardisees permettant une transition sure. Methodes Une procedure de relais tracheotomie-ventilation au masque a ete elaboree a partir de la litterature et de l’experience locale (faisabilite de la ventilation non-invasive : absence de lesions laryngo-tracheales, compensation de fuites adequate ; efficacite de la toux). Elle a ete testee chez trois patients atteints de maladies neuromusculaires severes mais stables (polyradiculonevrite chronique dans deux cas, amyotrophie spinale progressive dans un cas), a titre preliminaire. Resultats Les trois patients ont pu etre decanules et adaptes a une ventilation a domicile en 6, 7, et 10 jours, au terme desquels ils etaient tous rentres a leur domicile. Apres 4 mois dans 2 cas, 6 mois dans l’autre, aucune complication significative n’etait relevee, l’etat respiratoire sous ventilation au masque etait comparable a l’etat anterieur (tracheotomie), et les patients etaient satisfaits du changement. Conclusion L’algorithme propose semble permettre un passage rapide et sur de la tracheotomie a la ventilation au masque. Il reste, par des etudes a grande echelle, a verifier cette notion, et, au-dela, a identifier dans quelle population une telle demarche peut raisonnablement etre appliquee.

Resume Introduction De nombreuses inconnues demeurent quant a la place de la tracheotomie en reanimation. Les reticences a la realisation d’une tracheotomie sont nombreuses, surtout quand pre-existe une insuffisance respiratoire chronique (IRC), mais certaines donnees suggerent des benefices. Cette etude a pour objectifs d’evaluer l’impact de la tracheotomie sur la mortalite en reanimation et a l’hopital, et d’analyser et le role d’une IRC prealable. Materiel et methodes Etude retrospective cas-temoins, a partir d’une base de donnees prospective et exhaustive « MSI », sur 6 ans. Sur 2 901 malades admis pendant une periode de 5 ans, 882 patients intubes et ventiles ont ete identifies. 127 patients tracheotomises (T+) ont ete compares a 755 patients non tracheotomises (T-), et avec un sous-groupe « T-app » apparie a T+ pour la severite a l’admission (IGS2). Resultats La mortalite en reanimation et a l’hopital etait significativement moindre dans T+ que dans T- (28 vs. 52 % et 42 vs. 59 %), et les durees de sejour superieures. C’etait egalement le cas apres appariement sur la gravite a l’admission (T+ par rapport a T-app : 28 vs. 49 % et 42 vs. 53 %). Une IRC prealable n’influencait pas le devenir des patients tracheotomises, qu’il s’agisse d’une insuffisance respiratoire obstructive, restrictive « pulmonaire », ou neuromusculaire. Conclusions Une tracheotomie peut, dans certaines populations de patients ventiles artificiellement et dans certains contextes de soins, etre associee a une reduction de la mortalite hospitaliere.

Although traditionally associated with polycythemia, COPD has a systemic inflammatory component that could interfere with erythropoiesis. This study describes the distribution and prognostic value of the hematocrit in patients with severe COPD receiving long-term oxygen therapy (LTOT).A total of 2,524 patients with COPD, FEV1/vital capacity (VC)70%, FEV180% of predicted, and Pa(O2)7.3 kPa in whom a hematocrit was available at entry was identified between 1980 and 1999 in the French Association Nationale pour le Traitement à Domicile de l'Insuffisance Respiratoire chronic respiratory insufficiency and home-care database (male/female ratio, 5/1; mean +/- SD age, 68 +/- 10 years for men, and 70 +/- 10 years for women). Correlations between hematocrit, demographic data, and pulmonary function data were examined. A multivariate Cox proportional hazard regression was performed to identify prognostic factors.Mean hematocrit was 45.9 +/- 7.0% in men and 43.9 +/- 6.0% in women (39% in 12.6% of men, and36% in 8.2% of women) according to the World Health Organization definition of anemia. Hematocrit was negatively correlated with age (r = - 0.245) and FEV1/VC (r = - 0.068) and was positively correlated with Pa(CO2) (r = 0.161) and body mass index (r = 0.127). Multivariate analysis found hematocrit to be an independent predictor of survival, hospital admission rate, and cumulative duration of hospitalization. The 3-year survival was 24% (95% confidence interval, 16 to 33%) when the hematocrit was35%, and 70% (63 to 76%) when the hematocrit wasor = 55%.A low hematocrit is not uncommon in LTOT/COPD patients. Hematocrit is negatively associated with mortality and morbidity. Whether the association is causative or not and whether or not corrective measures are warranted remain to be determined.

Nutritional status is both important and difficult to assess in patients with Duchenne muscular dystrophy (DMD), particularly in those requiring mechanical ventilation (MV). The current authors evaluated body composition (bio-impedancemetry), resting energy expenditure (REE; indirect calorimetry) and energy intake in 20 adult patients with DMD using home MV (nocturnal: n = 13; continuous: n = 7) and 12 age-matched healthy controls. The patients were smaller in height than the controls and had a lower body weight. Most of the reduction in body mass index was accounted for by a reduction in fat free mass (FFM). REE (kJ) was significantly reduced in the patients (4559+/-853 kJ x 24 h(-1) versus 7407+/-1312 kJ x 24 h(-1)), but the difference disappeared after correction for FFM. REE and FFM were correlated in both the controls and patients, but less strongly in the latter, the lower strength of the association being due to the patients using continuous MV (REE and FFM uncorrelated). The food intake of the patients was 1.2+/-0.4 greater than their REE. This study shows that patients with advanced forms of Duchenne muscular dystrophy have balanced energy intakes and resting energy expenditure.

Polymyositis, dermatopolymyositis, and inclusion body myositis imply chronic inflammation of skeletal muscles. Pulmonary complications include aspiration pneumonia, interstitial pneumonitis, or respiratory muscle myositis. This study aims at better describing their impact on respiratory muscle. Twenty-three consecutive patients (12 PM, 5 DM, 6 IBM) were studied (static inspiratory and expiratory pressures; diaphragm function in terms of the mouth and transdiaphragmatic pressure responses to bilateral phrenic stimulation). Pulmonary parenchymatous abnormalities were mild (6 cases) or absent. The mouth pressure produced by phrenic stimulation was 6.83+/-3.01 cm H2O, with 18 patients (78%) diagnosed with diaphragm weakness (

Resume Un rappel physiopathologique de la respiration permet de comprendre comment un patient atteint de maladie neuromusculaire (MNM) peut avoir des symptomes respiratoires et quel peut etre l'impact des therapeutiques proposees. Une atteinte des muscles de l'inspiration, notamment du diaphragme, donne un syndrome restrictif et des troubles precoces du sommeil. Il faut realiser des examens precis mais simples pour l'evaluer et ce, de plus qu'une ventilation mecanique est un moyen parfaitement efficace pour pallier cette atteinte. Une atteinte des muscles expiratoires a des consequences, souvent negligees, sur la possibilite de se desencombrer et de parler. L'evaluation est la aussi utile car il existe egalement des possibilites mecaniques pour pallier ces incapacites. Enfin, il ne faut pas negliger l'atteinte de la deglutition qui peut avoir des consequences dramatiques sur le poumon, ainsi que les maladies thromboemboliques chez ces patients aux nombreux facteurs de risques cumules. Les outils d'evaluation des consequences respiratoires des maladies neuromusculaires et les differentes therapeutiques sont presentes de maniere exhaustive dans ce texte. Ces outils doivent etre accessibles a tout patient atteint d'une MNM. Le pneumologue doit ainsi faire partie integrante de la prise en charge multidisciplinaire d'un patient atteint de maladie neuromusculaire.