[Important step of weaning from mechanical ventilation: accurate assessment of respiratory muscle strength].

Mechanical ventilation (MV) is a powerful mean to rescue patients with respiratory failure. In view of the different etiology and basic respiratory function of patients with respiratory failure, weaning failure often occurs. Prolonged MV time is often accompanied by many complications. Thus, deeply understanding the pathophysiological changes of respiratory failure and strengthen monitoring of respiratory mechanics are helpful to optimize MV parameter settings, reduce ventilator-induced lung injury and wean from MV as early as possible. A successful weaning from MV depends on many factors, the most important factors are respiratory muscle strength, respiratory load and respiratory drive. Spontaneous breathing trial (SBT) is an important part of weaning process. The main purpose of implementing SBT is to screen patients and opportunities to weaning from MV, and find reversible reasons for not passing SBT. Because the accuracy of SBT in assessing weaning prognosis is about 85%, it is not adequate for difficult weaning patients. Standardized measurement of weaning indicators for patients with difficulty weaning is conducive to accurate assessment of respiratory muscle strength and improve the success rate of weaning from MV.

A comprehensive physical functional assessment of survivors of critical care unit stay due to COVID-19.

OBJECTIVE: To examine the physical function and respiratory muscle strength of patients - who recovered from critical COVID-19 - after intensive care unit discharge to the ward on Days one (D1) and seven (D7), and to investigate variables associated with functional impairment. METHODS: This was a prospective cohort study of adult patients with COVID-19 who needed invasive mechanical ventilation, non-invasive ventilation or high-flow nasal cannula and were discharged from the intensive care unit to the ward. Participants were submitted to Medical Research Council sum-score, handgrip strength, maximal inspiratory pressure, maximal expiratory pressure, and short physical performance battery tests. Participants were grouped into two groups according to their need for invasive ventilation: the Invasive Mechanical Ventilation Group (IMV Group) and the Non-Invasive Mechanical Ventilation Group (Non-IMV Group). RESULTS: Patients in the IMV Group (n = 31) were younger and had higher Sequential Organ Failure Assessment scores than those in the Non-IMV Group (n = 33). The short physical performance battery scores (range 0 - 12) on D1 and D7 were 6.1 ± 4.3 and 7.3 ± 3.8, respectively for the Non-Invasive Mechanical Ventilation Group, and 1.3 ± 2.5 and 2.6 ± 3.7, respectively for the IMV Group. The prevalence of intensive care unit-acquired weakness on D7 was 13% for the Non-IMV Group and 72% for the IMV Group. The maximal inspiratory pressure, maximal expiratory pressure, and handgrip strength increased on D7 in both groups, but the maximal expiratory pressure and handgrip strength were still weak. Only maximal inspiratory pressure was recovered (i.e., > 80% of the predicted value) in the Non-IMV Group. Female sex, and the need and duration of invasive mechanical were independently and negatively associated with the short physical performance battery score and handgrip strength. CONCLUSION: Patients who recovered from critical COVID-19 and who received invasive mechanical ventilation presented greater disability than those who were not invasively ventilated. However, they both showed marginal functional improvement during early recovery, regardless of the need for invasive mechanical ventilation. This might highlight the severity of disability caused by SARS-CoV-2.

Respiratory muscle strength can improve the prognostic assessment in COPD.

Impaired lung function, respiratory muscle weakness and exercise intolerance are present in COPD and contribute to poor prognosis. However, the contribution of the combination of these manifestations to define prognosis in COPD is still unknown. This study aimed to define cut-off points for both inspiratory and expiratory muscle strength (MIP and MEP, respectively) for mortality prediction over 42-months in patients with COPD, and to investigate its combination with other noninvasive established prognostic measures (FEV1, V̇O2peak and 6MWD) to improve risk identification. Patients with COPD performed pulmonary function, respiratory muscle strength, six-minute walk and cardiopulmonary exercise tests, and were followed over 42 months to analyze all-cause mortality. A total of 79 patients were included. The sample was mostly (91.1%) comprised of severe (n = 37) and very severe (n = 34) COPD, and 43 (54%) patients died during the follow-up period. Cut-points of ≤ 55 and ≤ 80 cmH2O for MIP and MEP, respectively, were associated with increased risk of death (log-rank p = 0.0001 for both MIP and MEP) in 42 months. Furthermore, MIP and MEP substantially improved the mortality risk assessment when combined with FEV1 (log-ranks p = 0.006 for MIP and p < 0.001 for MEP), V̇O2peak (log-rank: p < 0.001 for both MIP and MEP) and 6MWD (log-ranks: p = 0.005 for MIP; p = 0.015 for MEP). Thus, patients severely affected by COPD presenting MIP ≤ 55 and/or MEP ≤ 80 cmH2O are at increased risk of mortality. Furthermore, MIP and MEP substantially improve the mortality risk assessment when combined with FEV1, V̇O2peak and 6MWD in patients with COPD.

Assessment of respiratory muscles and motor function in children with SMA treated by nusinersen.

INTRODUCTION: Nusinersen is associated with an improvement in motor function in children with spinal muscular atrophy (SMA) but data on respiratory muscles strength are scarce. Respiratory muscles performance and lung function were evaluated in children with SMA 1c and 2 after six injections of nusinersen (M14). Results from patients with SMA2 were compared with data of age-matched historical controls. Motor function tests (MFM and HINE-2) were assessed at baseline and M14 in the treated patients. RESULTS: Sixteen children (2 SMA Type 1c and 14 SMA Type 2), mean age 9.4 ± 2.3 years, were included. The data of 14 historical SMA 2 controls (mean age 9.3 ± 1.9 years) were gathered. The strength of the global inspiratory muscles of SMA 2 treated with nusinersen, assessed on maximal static inspiratory pressure, forced vital capacity, and esophageal pressure during a maximal sniff was significantly better compared with historical controls (p < .05). A significant improvement in MFM and HINE-2 was observed in the patients with 16 SMA treated with nusinersen after 14 months as compared with baseline. CONCLUSION: In children with SMA Type 2, respiratory muscle performance was significantly better after six injections of nusinersen as compared with age-matched SMA Type 2 historical controls.

Breath-synchronized electrical stimulation of the expiratory muscles in mechanically ventilated patients: a randomized controlled feasibility study and pooled analysis.

BACKGROUND: Expiratory muscle weakness leads to difficult ventilator weaning. Maintaining their activity with functional electrical stimulation (FES) may improve outcome. We studied feasibility of breath-synchronized expiratory population muscle FES in a mixed ICU population ("Holland study") and pooled data with our previous work ("Australian study") to estimate potential clinical effects in a larger group. METHODS: Holland: Patients with a contractile response to FES received active or sham expiratory muscle FES (30 min, twice daily, 5 days/week until weaned). Main endpoints were feasibility (e.g., patient recruitment, treatment compliance, stimulation intensity) and safety. Pooled: Data on respiratory muscle thickness and ventilation duration from the Holland and Australian studies were combined (N = 40) in order to estimate potential effect size. Plasma cytokines (day 0, 3) were analyzed to study the effects of FES on systemic inflammation. RESULTS: Holland: A total of 272 sessions were performed (active/sham: 169/103) in 20 patients (N = active/sham: 10/10) with a total treatment compliance rate of 91.1%. No FES-related serious adverse events were reported. Pooled: On day 3, there was a between-group difference (N = active/sham: 7/12) in total abdominal expiratory muscle thickness favoring the active group [treatment difference (95% confidence interval); 2.25 (0.34, 4.16) mm, P = 0.02] but not on day 5. Plasma cytokine levels indicated that early FES did not induce systemic inflammation. Using a survival analysis approach for the total study population, median ventilation duration and ICU length of stay were 10 versus 52 (P = 0.07), and 12 versus 54 (P = 0.03) days for the active versus sham group. Median ventilation duration of patients that were successfully extubated was 8.5 [5.6-12.2] versus 10.5 [5.3-25.6] days (P = 0.60) for the active (N = 16) versus sham (N = 10) group, and median ICU length of stay was 10.5 [8.0-14.5] versus 14.0 [9.0-19.5] days (P = 0.36) for those active (N = 16) versus sham (N = 8) patients that were extubated and discharged alive from the ICU. During ICU stay, 3/20 patients died in the active group versus 8/20 in the sham group (P = 0.16). CONCLUSION: Expiratory muscle FES is feasible in selected ICU patients and might be a promising technique within a respiratory muscle-protective ventilation strategy. The next step is to study the effects on weaning and ventilator liberation outcome. TRIAL REGISTRATION: ClinicalTrials.gov, ID NCT03453944. Registered 05 March 2018-Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT03453944 .

Peak Cough Flow in Children with Neuromuscular Disorders.

PURPOSE: Patients with neuromuscular disease (NMD) experience weakened cough due to progressive respiratory muscle weakness. Peak cough flow (PCF) measurements derived from adult populations are used to recommend initiation of assisted cough therapies. The objective of this study was to characterize PCF values among pediatric patients with NMD. METHODS: Retrospective chart review was performed for patients seen in the multidisciplinary pediatric muscular dystrophy clinic from 2010 to 2016. Clinical and demographic variables included age, gender, ambulation status, and PCF measurements. RESULTS: 366 patients with an established diagnosis of NMD (median age 11.8 years) were included in this study. 102 (27.8%) out of the 366 patients were affected by Duchenne muscular dystrophy (DMD), 42 (11.5%) by congenital muscular dystrophy (CMD), 42 (11.5%) by Charcot Marie Tooth disease (CMT) and 24 (6.5%) by Becker's muscular dystrophy (BMD). The mean PCF values in DMD (255.8 L/min) and CMD (249.1 L/min) were lower than CMT (321.5 L/min) with p-values of 0.007 and 0.02, respectively. The mean PCF of BMD (333.3 L/min) was higher than that of DMD and CMD but the difference was not statistically significant. PCFs were not statistically different between ambulatory and non-ambulatory status (263.0 L/min versus 290.8 L/min, p = 0.12). Children under 10 years of age had lower PCF relative to older subjects (179.5 L/min versus 300.9 L/min, p < 0.0001). CONCLUSION: Baseline PCF values in young children are below the adult-specific values suggested for starting assisted cough techniques. Further longitudinal trials are required to derive pediatric-specific reference values for PCF in patients with NMD.

[Assessment of the respiratory muscles strength at various stages of ischemic stroke]. / Otsenka sily dykhatel'nykh myshts na razlichnykh stadiiakh ishemicheskogo insul'ta.

Power characteristics of the respiratory muscles (RM) in the dynamics of ischemic stroke (IS) is an important tool for the early diagnosis of RM dysfunction and development of individual programs for treatment at different stages of rehabilitation. AIM: To assess the power of RM in patients with IS at different stages of the disease. MATERIAL AND METHODS: Power characteristics of RM of 56 patients with IS with different severity of the disease were examined after 2-4, 5-6 and 13-14 months of IS onset. Maximum inspiratory (MIP) and expiratory (MEP) pressures in the oral cavity, maximum rate of pressure development (MRPD) and sniff nasal inspiratory pressure (SNIP) were determined. RESULTS AND CONCLUSION: A decrease in expiratory and inspiratory RM strength was shown in the early and late periods of IS, severity of which was depended on the severity of neurologic disorders. The bronchial obstruction resulted in RM dysfunction. Expiratory muscles weakness only was observed in the remote period while one third of patients had obstructive disorders of breathing. The functional activity of different RM at different IS stages was correlated with the smoking index, forced expiratory volume in the first second, forced vital capacity, skeletal muscles mass and severity of dyspnea, asthenia and disturbances of vital functions. These differences were the most obvious in elderly group of people. RM power examination of IS patients is an important mechanism of early diagnosis and rehabilitation.

Respiratory Muscle Assessment in Clinical Practice.

Respiratory muscle weakness is relatively rare in clinical practice; therefore, it is seldom a clinician's first thought. However, it should always be considered where a patient has unexplained breathlessness, respiratory failure, or experiences difficulty weaning from mechanical ventilation. Diaphragm weakness can often be ruled out by careful application of history, examination, and noninvasive bedside tests, although more quantitative tests exist. Where the predominant problem is respiratory muscle weakness, these tests convey useful prognostic information, which can be used for the management of an individual patient and to enrich study populations allowing reduced sample size in clinical trials.

Beyond inspiratory muscle strength: Clinical utility of single-breath work capacity assessment in veterans with COPD.

BACKGROUND: Inspiratory muscle function in COPD has been traditionally described in terms of maximal inspiratory pressure (MIP). Arguably, however, is the day-to-day relevance of MIP, given that individuals rarely need maximal inspiratory forces to perform general tasks, but rather repeated breathing muscle contractions which demand endurance. The sustained maximal inspiratory pressure (SMIP) reflects the ability of the respiratory muscles to maintain force over time (i.e. single-breath work capacity). We investigated the relationships between SMIP and COPD-related clinical outcomes, hypothesizing that SMIP would have superior correlational and discriminatory value when compared to MIP. METHODS: 61 males with mild-to-very severe airflow obstruction underwent measures of spirometry, whole-body plethysmography, symptomatology, comorbidity, quality of life, exacerbations and mental health. MIP and SMIP were obtained via the Test of Incremental Respiratory Endurance. RESULTS: The mean ±â€¯SD MIP and SMIP were 77.2 ±â€¯22.9 cmH2O and 407.9 ±â€¯122.8 PTU. Both MIP and SMIP positively correlated with pulmonary function, with SMIP displaying the highest correlations. We found significant differences in spirometry, hyperinflation, symptomatology, exacerbation frequency, comorbidity, quality of life and anxiety in subjects grouped as having reduced or normal single-breath work capacity. Finally, significantly lower SMIP values were found in individuals with an IC/TLC ratio ≤25%. CONCLUSIONS: The assessment of SMIP appears to have superior clinical value than MIP in COPD. Our analyses revealed that subjects whose SMIP was reduced experienced more severe airflow obstruction, greater hyperinflation, as well as worse health and mental status with increased symptomatology and impaired quality of life.

Assessment of Respiratory Muscle Weakness in Subjects With Neuromuscular Disease.

INTRODUCTION: Neuromuscular diseases (NMD) are a group of rare heterogeneous disorders that may be accompanied by respiratory muscle weakness. The simplest measurements of respiratory muscle strength are maximum inspiratory pressure (PImax) and maximum expiratory pressure (PEmax) of the mouth. Inspiratory muscle weakness can also be evaluated by the sniff test (sniff nasal inspiratory pressure method). This study tested the agreements in PImax and PEmax (measured by using a plethysmograph and portable equipment) as well as the correlations of PImax and PEmax by using the sniff nasal inspiratory pressure method, lung function, and arterial blood gas parameters in subjects with NMD. METHODS: This prospective, noninterventional study measured respiratory parameters in all the subjects with NMD who underwent measurement of maximum respiratory pressures. RESULTS: A total of 55 subjects with NMD were included. There were no statistically significant differences in PImax and PEmax measured by using a plethysmograph and portable equipment. Moreover, PImax showed a good correlation with the sniff nasal inspiratory pressure method. CONCLUSIONS: Measurements of PImax and PEmax by using portable equipment were equivalent to those performed by using the accepted standard, plethysmography, in the subjects with NMD. Noninvasive evaluation of the sniff test with the portable equipment correlates with PImax, which makes this approach a good method for measuring the maximum strength of inspiratory muscles in patients with NMD.

Cycle ergometer and inspiratory muscle training offer modest benefit compared with cycle ergometer alone: a comprehensive assessment in stable COPD patients.

BACKGROUND: Cycle ergometer training (CET) has been shown to improve exercise performance of the quadriceps muscles in patients with COPD, and inspiratory muscle training (IMT) may improve the pressure-generating capacity of the inspiratory muscles. However, the effects of combined CET and IMT remain unclear and there is a lack of comprehensive assessment. MATERIALS AND METHODS: Eighty-one patients with COPD were randomly allocated to three groups: 28 received 8 weeks of CET + IMT (combined training group), 27 received 8 weeks of CET alone (CET group), and 26 only received 8 weeks of free walking (control group). Comprehensive assessment including respiratory muscle strength, exercise capacity, pulmonary function, dyspnea, quality of life, emotional status, nutritional status, and body mass index, airflow obstruction, and exercise capacity index were measured before and after the pulmonary rehabilitation program. RESULTS: Respiratory muscle strength, exercise capacity, inspiratory capacity, dyspnea, quality of life, depression and anxiety, and nutritional status were all improved in the combined training and CET groups when compared with that in the control group (P<0.05) after pulmonary rehabilitation program. Inspiratory muscle strength increased significantly in the combined training group when compared with that in the CET group (ΔPImax [maximal inspiratory pressure] 5.20±0.89 cmH2O vs 1.32±0.91 cmH2O; P<0.05). However, there were no significant differences in the other indices between the two groups (P>0.05). Patients with weakened respiratory muscles in the combined training group derived no greater benefit than those without respiratory muscle weakness (P>0.05). There were no significant differences in these indices between the patients with malnutrition and normal nutrition after pulmonary rehabilitation program (P>0.05). CONCLUSION: Combined training is more effective than CET alone for increasing inspiratory muscle strength. IMT may not be useful when combined with CET in patients with weakened inspiratory muscles. Nutritional status had slight impact on the effects of pulmonary rehabilitation. A comprehensive assessment approach can be more objective to evaluate the effects of combined CET and IMT.

Noninvasive assessment of respiratory muscle strength and activity in Myotonic dystrophy.

OBJECTIVE: To evaluate sensitivity/specificity of the maximum relaxation rate (MRR) of inspiratory muscles, amplitude of electromyographic activity of the sternocleidomastoid (SCM), scalene (SCA), parasternal (2ndIS) and rectus abdominis (RA) muscles; lung function and respiratory muscle strength in subjects with Myotonic dystrophy type 1 (DM1) compared with healthy subjects. DESIGN AND METHODS: Quasi-experimental observational study with control group. MRR of inspiratory muscles, lung function and amplitude of the electromyographic activity of SCM, SCA, 2ndIS and RA muscles during maximum inspiratory pressure (PImax), maximum expiratory pressure (PEmax) and sniff nasal inspiratory pressure (SNIP) tests were assessed in eighteen DM1 subjects and eleven healthy. RESULTS: MRR was lower in DM1 group compared to healthy (P = 0.001) and was considered sensitive and specific to identify disease in DM1 and discard it in controls, as well as SNIP% (P = 0.0026), PImax% (P = 0.0077) and PEmax% (P = 0.0002). Contraction time of SCM and SCA was higher in DM1 compared to controls, respectively, during PImax (P = 0.023 and P = 0.017) and SNIP (P = 0.015 and P = .0004). The DM1 group showed lower PImax (P = .0006), PEmax (P = 0.0002), SNIP (P = 0.0014), and higher electromyographic activity of the SCM (P = 0.002) and SCA (P = 0.004) at rest; of 2ndIS (P = 0.003) during PEmax and of SCM (P = 0.02) and SCA (P = 0.03) during SNIP test. CONCLUSIONS: MD1 subjects presented restrictive pattern, reduced respiratory muscle strength, muscular electrical activity and MRR when compared to higher compared to controls. In addition, the lower MRR found in MD1 subjects showed to be reliable to sensitivity and specificity in identifying the delayed relaxation of respiratory muscles.

Assessment of mechanically ventilated patients intoxicated with organophosphates by a novel surface electromyographic index.

PURPOSE: We present a new electromyographic index, named Engagement of Respiratory Muscle (ERM), for assessing the level of participation of respiratory muscles during spontaneous breathing test in patients poisoned with organophosphorus compound. METHODS: Diaphragm and sternocleidomastoid muscles activity was recorded by surface electromyography during spontaneous breathing test. A population of 23 patients poisoned with organophosphates and mechanically ventilated, and a control group of 28 healthy subjects were analyzed. RESULTS: All patients developed respiratory failure and 48% were diagnosed with intermediate syndrome by medical staff. The ERM index classified the patients in three clusters (p-value<0.005): Cluster I presented more engagement of the sternocleidomastoid compared to diaphragm, Cluster II had low muscle engagement of both muscles and also muscle weakness, Cluster III were characterized for the diaphragm recovery associated with higher engagement. The control group showed a similar muscle engagement to Cluster III. The capacity of ERM index for classifying patients with (sensitivity) and without (specificity) muscle weakness were 90.91% and 100% respectively. CONCLUSIONS: The ERM is a promising index to assess the level of participation of respiratory muscle on spontaneous breathing test in patients poisoned with organophosphorus compounds, which could improve the extubation prognosis for these patients.

Optimal method for assessment of respiratory muscle strength in neuromuscular disorders using sniff nasal inspiratory pressure (SNIP).

BACKGROUND: The ability to accurately determine respiratory muscle strength is vitally important in patients with neuromuscular disorders (NMD). Sniff nasal inspiratory pressure (SNIP), a test of inspiratory muscle strength, is easier to perform for many NMD patients than the more commonly used determination of maximum inspiratory pressure measured at the mouth (MIP). However, due to an inconsistent approach in the literature, the optimal technique to perform the SNIP maneuver is unclear. Therefore, we systematically evaluated the impact of performing the maneuver with nostril contralateral to the pressure-sensing probe open (SNIPOP) versus closed (SNIPCL), on determination of inspiratory muscle strength in NMD patients as well as control subjects with normal respiratory muscle function. METHODS: NMD patients (n = 52) and control subjects without respiratory dysfunction (n = 52) were studied. SNIPOP, SNIPCL, and MIP were measured during the same session and compared using ANOVA. Agreement and bias were assessed with intraclass correlation coefficients (ICC) and Bland-Altman plots. RESULTS: Mean MIP values were 58.2 and 94.0 cmH2O in NMD and control subjects, respectively (p<0.001). SNIPCL was greater than SNIPOP in NMD (51.9 ±31.0 vs. 36.9 ±25.4 cmH2O; p<0.001) as well as in controls (89.2 ±28.1 vs. 69.2 ±29.2 cmH2O; p<0.001). In both populations, the ICC between MIP and SNIPCL (NMD = 0.78, controls = 0.35) was higher than for MIP and SNIPOP (NMD = 0.53, controls = 0.06). In addition, SNIPCL was more often able to exclude inspiratory muscle weakness than SNIPOP. CONCLUSIONS: SNIPCL values are systematically higher than SNIPOP in both normal subjects and NMD patients. Therefore, SNIPCL is a useful complementary test for ruling out inspiratory muscle weakness in individuals with low MIP values.

Respiratory Muscle Assessment in Acute Guillain-Barré Syndrome.

PURPOSE: Guillain-Barré Syndrome (GBS) is a life-threatening disease due to respiratory muscle involvement. This study aimed at objectively assessing the course of respiratory muscle function in GBS subjects within the first week of admission to an intensive care unit. METHODS: Medical Research Council Sum Score (MRC-SS), vigorimetry, spirometry, and respiratory muscle function tests (inspiratory/expiratory muscle strength: PImax/PEmax, sniff nasal pressure: SnPna) were assessed twice daily. GBS Disability Score (GBS-DS) was assessed once daily. On days one (d1) and seven (d7), blood gases and twitch mouth pressure during magnetic phrenic nerve stimulation (Pmo,tw) were additionally evaluated. RESULTS: Nine subjects were included. MRC-SS, vigorimetry, PImax, and SnPna increased between d1 and d7. GBS-DS, spirometry and Pmo,tw remained unaltered. Only SnPna correlated closely with the MRC-SS on both d1 (r = 0.77, p = 0.02) and d7 (r = 0.74, p = 0.02). CONCLUSION: SnPna was the only parameter that correlated with MRC-SS, while the current gold standard of spirometry measurement did not.

Safety assessment of epidural wire electrodes for cough production in a chronic pig model of spinal cord injury.

BACKGROUND: It is our hypothesis that high intensity spinal cord stimulation (SCS) to restore an effective cough mechanism using wire leads, will result in significant activation of target neurons without tissue injury or electrode corrosion. METHODS: Adult mini-pigs underwent chronic spinal cord compression, followed by implantation of parallel wire leads on the dorsal epidural surface of the spinal cord, with stimulation contacts at the T9 and T12, and control electrode contacts at the T2 and T5 levels. After 3 months of daily SCS, airway pressure generation (P), tissue in the area of the stimulating and control electrodes and electrode leads were examined. P was also assessed in acute animals, which served as controls. RESULTS: Mean P at FRC was 54±5cmH2O and 109±11cmH2O in the control and chronically stimulated animals, respectively (p<0.05). There was minimal tissue reaction in the area of the stimulating and control electrodes. All sets of leads revealed no evidence of electrode corrosion. COMPARISON WITH EXISTING METHODS: Previous porcine models of chronic spinal cord injury (SCI) were developed to study neurological and regenerative outcomes. Our method of chronic SCI porcine model was developed to evaluate the safety of electrical SCS to restore expiratory muscle function. CONCLUSION: Chronic SCS with wire lead electrodes results in significant increases in P without evidence of significant adverse tissue reaction, nor evidence of electrode corrosion. This method may be a safe and useful technique to restore a functional cough in spinal cord injured subjects.

A decision tree to assess short-term mortality after an emergency department visit for an exacerbation of COPD: a cohort study.

BACKGROUND: Creating an easy-to-use instrument to identify predictors of short-term (30/60-day) mortality after an exacerbation of chronic obstructive pulmonary disease (eCOPD) could help clinicians choose specific measures of medical care to decrease mortality in these patients. The objective of this study was to develop and validate a classification and regression tree (CART) to predict short term mortality among patients evaluated in an emergency department (ED) for an eCOPD. METHODS: We conducted a prospective cohort study including participants from 16 hospitals in Spain. COPD patients with an exacerbation attending the emergency department (ED) of any of the hospitals between June 2008 and September 2010 were recruited. Patients were randomly divided into derivation (50%) and validation samples (50%). A CART based on a recursive partitioning algorithm was created in the derivation sample and applied to the validation sample. RESULTS: Two thousand four hundred eighty-seven patients, 1252 patients in the derivation sample and 1235 in the validation sample, were enrolled in the study. Based on the results of the univariate analysis, five variables (baseline dyspnea, cardiac disease, the presence of paradoxical breathing or use of accessory inspiratory muscles, age, and Glasgow Coma Scale score) were used to build the CART. Mortality rates 30 days after discharge ranged from 0% to 55% in the five CART classes. The lowest mortality rate was for the branch composed of low baseline dyspnea and lack of cardiac disease. The highest mortality rate was in the branch with the highest baseline dyspnea level, use of accessory inspiratory muscles or paradoxical breathing upon ED arrival, and Glasgow score <15. The area under the receiver-operating curve (AUC) in the derivation sample was 0.835 (95% CI: 0.783, 0.888) and 0.794 (95% CI: 0.723, 0.865) in the validation sample. CART was improved to predict 60-days mortality risk by adding the Charlson Comorbidity Index, reaching an AUC in the derivation sample of 0.817 (95% CI: 0.776, 0.859) and 0.770 (95% CI: 0.716, 0.823) in the validation sample. CONCLUSIONS: We identified several easy-to-determine variables that allow clinicians to classify eCOPD patients by short term mortality risk, which can provide useful information for establishing appropriate clinical care. TRIAL REGISTRATION: NCT02434536.

Clinical and pathophysiological clues of respiratory dysfunction in late-onset Pompe disease: New insights from a comparative study by MRI and respiratory function assessment.

Respiratory insufficiency commonly develops in patients with Late Onset Pompe Disease (LOPD). It is conceivable that a timely starting of enzyme replacement therapy could avoid this life-threatening complication. Respiratory function in LOPD is commonly evaluated with standard pulmonary tests which do not extensively provide an accurate definition of the muscular pathophysiology. In eleven patients with LOPD and five healthy subjects, we compared pulmonary function results with MRI data, based on scans of the right lung acquired on maximum expiration and inspiration. We observed that variations in the cranio-caudal lung height and of lung areas in inspiration and expiration (lung delta) as well as the area of diaphragmatic movement strongly correlated with pulmonary function results. Moreover, MRI data confirmed that development of respiratory insufficiency in LOPD is mainly due to the diaphragmatic weakness with sparing of the antero-posterior chest expansion related to the activity of the intercostal muscles. These results suggest that respiratory muscle MRI is a quick, useful and reproducible tool for patient management as well as a reliable outcome measure for future LOPD therapeutic trials.