[show abstract][hide abstract] ABSTRACT: Purpose: We have developed a software that automatically calculates respiratory effort indices, including intrinsic end expiratory pressure (PEEPi) and esophageal pressure-time product (PTPeso). The aim of this study was to validate this software.
Materials and Methods: The software first identifies respiratory periods. Then, pressure or flow waveforms with artifacts are automatically excluded from analyses. Clean signals are averaged to provide a reference mean cycle from which respiratory parameters are extracted. The onset of the inspiratory effort is detected automatically by looking backward from the onset of inspiratory flow to the first point where the esophageal pressure derivative is equal to zero (inflection point). PEEPi is derived from this point. Twenty-three recordings from 16 patients were analyzed with the algorithm and compared with experts' manual analysis of signals: 15 recordings were performed during spontaneous breathing, 1 during non-invasive mechanical ventilation, and 7 under both conditions.
Results: For all values, the coefficients of determinations (r2) exceeded 0.94 (p<0.001). The bias (mean difference) between PEEPi calculated by hand and automatically was -0.26 ± 0.52 cmH2O during spontaneous breathing and the precisions (standard deviations of the differences) was 0.52 cmH2O with limits of agreement of 0.78 and -1.30 cmH2O. The mean difference between PTPeso calculated by hand and automatically was -0.38 ± 1.42 cmH2O.sec/cycle with limits of agreement of 2.46 and -3.22 cmH2O.sec/cycle.
Conclusions: Our program provides a reliable method for the automatic calculation of PEEPi and respiratory effort indices, which may facilitate the use of these variables in clinical practice. The software is open source and can be improved with the development and validation of new respiratory parameters.
[show abstract][hide abstract] ABSTRACT: We have developed a software that automatically calculates respiratory effort indices, including intrinsic end expiratory pressure (PEEPi) and esophageal pressure-time product (PTPeso). The aim of this study was to validate this software.
The software first identifies respiratory periods. Then, pressure or flow waveforms with artifacts are automatically excluded from analyses. Clean signals are averaged to provide a reference mean cycle from which respiratory parameters are extracted. The onset of the inspiratory effort is detected automatically by looking backward from the onset of inspiratory flow to the first point where the esophageal pressure derivative is equal to zero (inflection point). PEEPi is derived from this point. Twenty-three recordings from 16 patients were analyzed with the algorithm and compared with experts' manual analysis of signals: 15 recordings were performed during spontaneous breathing, 1 during non-invasive mechanical ventilation, and 7 under both conditions.
For all values, the coefficients of determinations (r(2)) exceeded 0.94 (p<0.001). The bias (mean difference) between PEEPi calculated by hand and automatically was -0.26±0.52 cmH2O during spontaneous breathing and the precisions (standard deviations of the differences) was 0.52 cmH2O with limits of agreement of 0.78 and -1.30 cmH2O. The mean difference between PTPeso calculated by hand and automatically was -0.38±1.42 cmH2O.sec/cycle with limits of agreement of 2.46 and -3.22 cmH2O.sec/cycle.
Our program provides a reliable method for the automatic calculation of PEEPi and respiratory effort indices, which may facilitate the use of these variables in clinical practice. The software is open source and can be improved with the development and validation of new respiratory parameters.
[show abstract][hide abstract] ABSTRACT: Battery life (BL) of portable home ventilators batteries are reported by manufacturers. The aim of the study was to evaluate the effects of ventilatory mode, respiratory frequency, positive end-expiratory pressure (PEEP), and leaks on the BL of 5 commercially available portable ventilators.
The effect of the ventilatory mode (volume controlled-continuous mandatory ventilation [VC-CMV] vs Pressure Support ventilation [PS]), PEEP 5 cmH2O, respiratory frequency (10, 15 and 20 cycles/min), and leaks during both VTV and PS on the BL of5 ventilators (Elisee 150, Monnal T50, PB 560, Vivo 50, and Trilogy 100) were evaluated. Each ventilator was ventilated with a test lung at a tidal volume of 700 ml and an inspiratory time 1.2 in the absence of leaks.
The switch of a VC-CMV mode for a PS mode or the addition of PEEP did not significantly change the ventilator BL. The increase of the respiratory frequency from 10 to 20 cycles/min decreased the BL of 18 ± 11% (P<0.005). Leaks were associated with an increase of the BL during the VC-CMV mode (18 ± 20%, P<0.05) whereas the BL decreased during the PS mode (-13 ± 15%, P<0.05).
The BL of home ventilators depends on the ventilatory settings. The BL is not affected by the ventilator mode (VC-CMV or PS) or the addition of PEEP. BL decreases with the increase in respiratory frequency and during leaks with a PS mode whereas leaks increase the duration of the ventilator BL during VC-CMV.
[show abstract][hide abstract] ABSTRACT: OBJECTIVE: Communication is a major issue for patients with tracheostomy who are supported by mechanical ventilation. The use of positive end-expiratory pressure (PEEP) may restore speech during expiration; however, the optimal PEEP level for speech may vary individually. We aimed to improve speech quality with an individually adjusted PEEP level delivered under the patient's control to ensure optimal respiratory comfort. METHODS: Optimal PEEP level (PEEPeff), defined as the PEEP level that allows complete expiration through the upper airways, was determined for 12 patients with neuromuscular disease who are supported by mechanical ventilation. Speech and respiratory parameters were studied without PEEP, with PEEPeff, and for an intermediate PEEP level. Flow and airway pressure were measured. Microphone speech recordings were subjected to both quantitative and qualitative assessments of speech, including an intelligibility score, a perceptual score, and an evaluation of prosody determined by two speech therapists blinded to PEEP condition. RESULTS: Text reading time, phonation flow, use of the respiratory cycle for phonation, and speech comfort significantly improved with increasing PEEP, whereas qualitative parameters remained unchanged. This resulted mostly from the increase of the expiratory volume through the upper airways available for speech for all patients combined, with a rise in respiratory rate for nine patients. Respiratory comfort remained stable despite high levels of PEEPeff (median, 10.0 cm H2O; interquartile range, 9.5-12.0 cm H2O). CONCLUSIONS: Patient-controlled PEEP allowed for the use of high levels of PEEP with good respiratory tolerance and significant improvement in speech (enabling phonation during the entire respiratory cycle in most patients). The device studied could be implemented in home ventilators to improve speech and, therefore, autonomy of patients with tracheostomy. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT01479959; URL: clinicaltrials.gov.
[show abstract][hide abstract] ABSTRACT: ABSTRACT BACKGROUND: The objective was to determine whether optoelectronic plethysmography (OEP) can detect asymmetrical ventilation related to unilateral or asymmetrical diaphragmatic weakness, suggesting usefulness as a diagnostic tool. PATIENTS AND METHODS: 13 patients with suspected asymmetrical diaphragmatic weakness based on dyspnea and hemidiaphragm elevation on the chest radiograph were studied, as well as 3 patients with maltase acid deficiency (a cause of symmetrical diaphragmatic weakness). The transdiaphragmatic pressure response to unilateral magnetic stimulation (latPdiTw) and the diaphragm compound muscle action potentials (CMAPs) elicited by transcutaneous electrical stimulation of each phrenic nerve as well as OEP were performed. RESULTS: The CMAPs and latPdiTw showed unilateral or predominantly unilateral diaphragmatic weakness in 9 of the 13 patients. By OEP, the affected side of the thorax and abdomen contributed less than 45% of the inspiratory capacity in each of these 9 patients, whereas no asymmetry was noted in the other 4 patients or in the 3 patients with maltase acid deficiency. All patients preferred OEP over CMAP or latPdiTw. CONCLUSION: OEP detected asymmetric ventilation in all patients diagnosed with unilateral diaphragm weakness and in no patients without this diagnosis. Thus, OEP is an effective noninvasive alternative that is preferred by the patients over CMAP response and latPdiTw.
[show abstract][hide abstract] ABSTRACT: BACKGROUND: To determine whether optoelectronic plethysmography accurately evaluated vital capacity (VC) in patients with respiratory muscle dysfunction of variable severity, including those with paradoxical abdominal movements. METHODS: In 20 patients, VC was measured in the supine position using both spirometry and optoelectronic plethysmography (six optoelectronic cameras and 52 reflective markers on the anterior chest wall). RESULTS: Spirometry VC correlated positively with optoelectronic VC (r²=0.993, p<0.0001) and the regression line was very close to the identity line (VCopto (mL) =-1.202 + 1.007*VCspiro (mL)). A Bland and Altman plot showed that the mean difference was -20 mL (95%CI: -63 mL to 24 mL) and the limits of agreement were 163 mL (95%CI: 106 mL to 231 mL) and -203 mL (95% CI: -271 mL to -146 mL). The difference between the two values expressed as the percentage of the mean value was less than 15% in all 20 participants, less than 10% in 17 (85%) participants, and less than 5% in 11 (55%) participants. The difference expressed as the percentage of the mean value was unrelated to the contribution of abdominal motion to VC (r =0.02 and p=0.94) but was significantly related to body mass index (r=0.53, p=0.015). CONCLUSIONS: Optoelectronic plethysmography is accurate and suitable for VC measurement in patients with various degrees of respiratory failure, including those with paradoxical abdominal movements. This non-invasive method may be an attractive alternative for accurately measuring VC in the event of air leakage (through the mouth or tracheostomy) or when patients are unable to breathe with the dead space added by the spirometer.
[show abstract][hide abstract] ABSTRACT: Inspiratory unintentional leaks (IULs) during noninvasive ventilation (NIV) adversely affect the sleep and the effectiveness of mechanical ventilation (MV). The aim of this study was to assess the effects of nocturnal IULs in Duchenne muscular dystrophy (DMD) patients with a tracheostomy and uncuffed tube comparatively with NIV patients.
Polysomnography with transcutaneous partial pressure of carbon dioxide (PtcCO(2)) recording and blood gas measurement was performed in 26 stable tracheostomized DMD patients using home MV, among whom 11 were matched with NIV patients.
IULs occurred during 29.4% [1.7-61.9%] (median [IQR]) of the total sleep time. By univariate regression analysis, the closest correlation with IUL duration was for daytime base excess (r(2)=0.69, P<0.0001), followed by daytime bicarbonate level. In a stepwise multiple regression analysis, only base excess remained significantly correlated. Sleep and respiratory parameters improved in the four patients who agreed to use cuffed tubes. Tracheostomized patients had lower maximal PtcCO(2) (P=0.02) and base excess values (P=0.045) compared to NIV controls.
Tracheostomy does not guarantee that MV is effective during sleep, as IULs may occur, but ensures better nocturnal gas exchanges than NIV. DMD patients should be evaluated using at least blood gas measurement, nocturnal oximetry, and PtcCO(2) monitoring.
Sleep Medicine 07/2012; 13(8):1056-65. · 3.49 Impact Factor
[show abstract][hide abstract] ABSTRACT: Ventilation improvements have led to an increased number of ventilator-dependent neuromuscular patients. In order to ensure adequate ventilation efficiency and security while maintaining quality of life, the check-list is large. Two « life support » ventilators are mandatory, while different interfaces may be required for nighttime and daytime ventilation, in order to maintain communication. Airways clearance is a major goal. It requires physiotherapists, cough assistance devices and the participation of the relatives. The decision of tracheostomy needs to be individually evaluated. Permanent anticipation is necessary.
Revue des Maladies Respiratoires Actualites 07/2012; 4(3):194–198.
[show abstract][hide abstract] ABSTRACT: Myotonic Dystrophy Type 1 (DM1) is the most common autosomal dominant muscular dystrophy worldwide. The cognitive defects and cardiac arrrthymias are usual. The respiratory drive is frequently abnormal with hypercapnia, hypersomnia and sleep apnea (obstructive or central). At present, therapy addresses correcting hormonal and glycemic balance, removing cataract, preventing respiratory failure and, above all, major cardiac disturbances. The respiratory management aims to normalize PaCO2 and sleep disturbances and to prevent cardiac arrrthymias. Implement non invasive ventilation is complex in this situation with cognitive deficits. The observance is low, perhaps owing to the misunderstanding and because of the lack of perceived benefit in terms of quality of life or hypersomnia.
Revue des Maladies Respiratoires Actualites 07/2012; 4(3):190–193.
[show abstract][hide abstract] ABSTRACT: Amyotrophic lateral sclerosis (ALS) is a fast course neuromuscular disease. One of the main specificities of this disease is the few number of ventilated patients whereas the benefit of this treatment has been demontrated. Furthermore, the recommendations exist but are not applied and the care is not enough anticipated. The improvement relate to the networks between city and hospital and the research.
Revue des Maladies Respiratoires Actualites 07/2012; 4(3):187–189.
[show abstract][hide abstract] ABSTRACT: Pulse oximetry alone has been suggested to determine which patients on home mechanical ventilation (MV) require further investigation of nocturnal gas exchange. In patients with neuromuscular diseases, alveolar hypoventilation (AH) is rarely accompanied with ventilation-perfusion ratio heterogeneity, and, therefore, oximetry may be less sensitive for detecting AH than in patients with lung disease.
To determine whether pulse oximetry (S(pO(2))) and transcutaneous carbon dioxide (P(tcCO(2))) during the same night were interchangeable or complementary for assessing home MV efficiency in patients with neuromuscular diseases.
Data were collected retrospectively from the charts of 58 patients with chronic neuromuscular respiratory failure receiving follow-up at a home MV unit. S(pO(2)) and P(tcCO(2)) were recorded during a 1-night hospital stay as part of standard patient care. We compared AH detection rates by P(tcCO(2)), S(pO(2)), and both.
AH was detected based on P(tcCO(2)) alone in 24 (41%) patients, and based on S(pO(2)) alone with 3 different cutoffs in 3 (5%), 8 (14%), and 13 (22%) patients, respectively. Using both P(tcCO(2)) and S(pO(2)) showed AH in 25 (43%) patients.
Pulse oximetry alone is not sufficient to exclude AH when assessing home MV efficiency in patients with neuromuscular diseases. Both P(tcCO(2)) and S(pO(2)) should be recorded overnight as the first-line investigation in this population.
Respiratory care 02/2012; 57(9):1425-30. · 2.03 Impact Factor
[show abstract][hide abstract] ABSTRACT: Expiratory flow towards the upper airway after swallowing serves to expel liquid or food particles misdirected towards the trachea during swallowing. However, expiration may not occur consistently after swallowing in tracheostomised patients with an open tracheostomy tube. We investigated the effect of a speaking valve (SV) on breathing-swallowing interactions and on the volume expelled through the upper airway after swallowing.
Eight tracheostomised neuromuscular patients who were able to breathe spontaneously were studied with and without an SV. Breathing-swallowing interactions were investigated by chin electromyography, cervical piezoelectric sensor, and nasal and tracheal flow recording. Three water-bolus sizes (5, 10, and 15 mL) were tested in random order.
Swallowing characteristics and breathing-swallowing synchronisation were not influenced by SV use. However, expiratory flow towards the upper airway after swallowing was negligible without the SV and was restored by adding the SV.
In tracheostomised patients, protective expiration towards the upper airway after swallowing is restored by the use of an SV.
European Journal of Intensive Care Medicine 11/2011; 38(1):85-90. · 5.17 Impact Factor
[show abstract][hide abstract] ABSTRACT: The objective is to determine whether maximal inspiratory pressure (P (imax)) measurement is more sensitive than vital capacity (VC) measurement to detect acute respiratory muscle failure considering a theoretical curvilinear relationship between volume and pressure.
Review of VC and P (imax) of all patients hospitalized in ICU for Guillain-Barré syndrome (GBS) and myasthenia gravis (MG) exacerbation.
84 consecutive caucasian patients between 19- and 70-years-old hospitalized in intensive care unit from April 2008 to December 2010, for MG exacerbation (44 patients) and GBS (40 patients). The regression curve between VC and P (imax) was linear rather than exponential (r = 0.599, P > 0.0001). The contingency table demonstrated agreement between VC and P (imax) (χ(2 )= 26.7, P = 0.0001), with similar number of patients having abnormal P (imax) associated to normal VC and normal P (imax) associated to abnormal VC (9 (10.7%) vs. 8 (9.5%) respectively). Six of the patients developed an important decrease of VC from normal value to less than 60% of the predicted value and did not present evident curvilinear relationship between VC and P (imax) during this follow-up.
Because the regression between VC and P (imax) was linear rather than curvilinear, P (imax) was not more sensitive than VC for early detection of respiratory muscle failure in patients hospitalized in ICU for GBS and MG exacerbation. Therefore, VC remains well suited to assess acute respiratory muscle failure and P (imax) gives poor additional information.
Neurocritical Care 07/2011; 17(2):236-9. · 3.04 Impact Factor
[show abstract][hide abstract] ABSTRACT: Pompe disease is a rare metabolic myopathy caused by lysosomal α-glucosidase deficiency. Pompe disease ranges from a rapidly progressive course when symptoms present in infancy to a more slowly progressive rate when symptoms present in childhood or adulthood. This open-label prospective exploratory study investigated the effect of 12 months of recombinant enzyme replacement therapy in 5 adult patients who had already advanced to a very severe stage of Pompe disease. Muscular and respiratory function, quantitative muscle testing and spirometry were assessed. Four patients were tracheostomized. Respiratory parameters did not deteriorate. A moderate improvement in sitting/supine slow vital capacity in 2 patients (from 7% to 11% and 28% to 32% of predicted) and reductions of ventilation support in 2 patients was observed. Three patients, wheelchair bound at baseline, improved sitting and proximal motor function; 2 patients improved in their ability to stand and transfer. The treatment was well tolerated. Alglucosidase alfa may stabilize or even slightly improve muscle strength and respiratory function among patients with severe Pompe disease.
[show abstract][hide abstract] ABSTRACT: Extraction and purification of an acid β-glucosidase from human placenta (alglucerase) for the treatment of Gaucher disease, replaced a few years later by a recombinant enzyme (imiglucérase, Cerezyme(®)), has paved the way to the development of enzyme replacement therapies (ERT) for the treatment of lysosomal storage diseases (LSD) among which Fabry disease for which the long-term efficacy of the two currently available preparations (agalsidase alfa, Replagal(®) and Fabrazyme(®)) is still being investigated. Mucopolysaccharidosis (MPS) type I (Hurler and Scheie diseases), II (Hunter syndrome) and VI (Maroteaux-Lamy disease) also benefit from ERT using laronidase (Aldurazyme(®)), idursulfase (Elaprase(®)) and galsulfase (Naglazyme(®)), respectively. ERT reduces the hepatosplenomegaly and improves the physical and respiratory capacities of MPS patients with a globally acceptable safety profile although the possibility of infusion-associated should always be kept in mind. Alglucosidase alpha (Myozyme(®)) improves the cardiomyopathy and life expectancy of infants suffering from Pompe disease and is under evaluation for the treatment of the juvenile and adult forms of the disease. CNS involvement remains a major challenge for many LSD and innovative research and approaches are needed to address the fact that recombinant enzymes do not cross the blood-brain barrier and therefore are not expected to lead to any improvement in CNS damages, except if alternative routes such as intrathecal administration would be developed. Molecular chaperones (e.g. migalastat for Fabry disease) and inhibitors of glucosylceramide synthesis (e.g. eliglustat tartrate for Gaucher disease) are currently under investigation in various clinical trials.
La Revue de Médecine Interne 12/2010; 31 Suppl 2:S279-91. · 0.90 Impact Factor