Hélène Prigent

Publications (21)77.4 Total impact

• Article: Patient-Controlled Positive End-Expiratory Pressure With Neuromuscular Disease: Effect on Speech in Patients With Tracheostomy and Mechanical Ventilation Support.

  Marine Garguilo, Karl Leroux, Michèle Lejaille, Sophie Pascal, David Orlikowski, Frédéric Lofaso, Hélène Prigent
  [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.
  Chest 05/2013; 143(5):1243-1251. · 5.25 Impact Factor
• Article: Optoelectronic plethysmography as an alternative method for the diagnosis of unilateral diaphragmatic weakness.

  Julien Boudarham, Didier Pradon, Hélène Prigent, Line Falaize, Marie-Christine Durand, Henri Meric, Michel Petitjean, Frédéric Lofaso
  [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.
  Chest 03/2013; · 5.25 Impact Factor
• Article: Optoelectronic Vital Capacity Measurement for Restrictive Diseases.

  Julien Boudarham, Didier Pradon, Hélène Prigent, Isabelle Vaugier, Frédéric Barbot, Nadège Letilly, Line Falaize, David Orlikowski, Michel Petitjean, Frédéric Lofaso
  [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.
  Respiratory care 08/2012; · 2.01 Impact Factor
• Article: Efficiency of invasive mechanical ventilation during sleep in Duchenne muscular dystrophy.

  Julie Nardi, Hélène Prigent, Betty Garnier, François Lebargy, Maria-Antonia Quera-Salva, David Orlikowski, Frédéric Lofaso
  [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. · 3.40 Impact Factor
• Article: Supine volume drop and diaphragmatic function in adults with Pompe disease.

  Hélène Prigent, David Orlikowski, Pascal Laforêt, Nadège Letilly, Line Falaize, Nadine Pellegrini, Djillali Annane, Jean-Claude Raphael, Frédéric Lofaso
  European Respiratory Journal 06/2012; 39(6):1545-6. · 5.89 Impact Factor
• Article: Nocturnal oximetry and transcutaneous carbon dioxide in home-ventilated neuromuscular patients.

  Julie Nardi, Hélène Prigent, Annie Adala, Mikaëlle Bohic, François Lebargy, Maria-Antonia Quera-Salva, David Orlikowski, Frédéric Lofaso
  [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. · 2.01 Impact Factor
• Article: Effect of a tracheostomy speaking valve on breathing-swallowing interaction.

  Hélène Prigent, Michèle Lejaille, Nicolas Terzi, Djillali Annane, Marjorie Figere, David Orlikowski, Frédéric Lofaso
  [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
• Article: Vital capacity versus maximal inspiratory pressure in patients with guillain-barré syndrome and myasthenia gravis.

  Hélène Prigent, David Orlikowski, Nadège Letilly, Line Falaize, Djilali Annane, Tarek Sharshar, Frédéric Lofaso
  [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. · 2.47 Impact Factor
• Article: Recombinant human acid alpha-glucosidase (rhGAA) in adult patients with severe respiratory failure due to Pompe disease.

  David Orlikowski, Nadine Pellegrini, Hélène Prigent, Pascal Laforêt, Robert Carlier, Pierre Carlier, Bruno Eymard, Frédéric Lofaso, Djillali Annane
  [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.
  Neuromuscular Disorders 05/2011; 21(7):477-82. · 2.80 Impact Factor
• Article: Speech effects of a speaking valve versus external PEEP in tracheostomized ventilator-dependent neuromuscular patients.

  Hélène Prigent, Marine Garguilo, Sophie Pascal, Samuel Pouplin, Justine Bouteille, Michèle Lejaille, David Orlikowski, Frédéric Lofaso
  [show abstract] [hide abstract]
  ABSTRACT: Many patients with respiratory failure related to neuromuscular disease receive chronic invasive ventilation through a tracheostomy. Improving quality of life, of which speech is an important component, is a major goal in these patients. We compared the effects on breathing and speech of low-level positive end-expiratory pressure (PEEP, 5 cmH(2)O) and of a Passy-Muir speaking valve (PMV) during assist-control ventilation. We studied ten patients with neuromuscular disorders, between December 2008 and April 2009. Flow was measured using a pneumotachograph. Microphone speech recordings were subjected to both quantitative measurements and qualitative assessments; the latter consisted of both an intelligibility score (using a French adaptation of the Frenchay Dysarthria Assessment) and a perceptual score determined by two speech therapists. Text reading time, perceptive score, intelligibility score, speech comfort, and respiratory comfort were similar with PEEP and PMV. During speech with 5 cmH(2)O PEEP, six of the ten patients had no return of expiratory gas to the expiratory line and, therefore, had the entire insufflated volume available for speech, a condition met during PMV use in all patients. During speech, the respiratory rate increased by at least 3 cycles/min above the backup rate in seven patients with PEEP and in none of the patients with PMV. Low-level PEEP is as effective as PMV in ensuring good speech quality, which might be explained by sealed expiratory line with low-level PEEP and/or respiratory rate increase during speech with PEEP observed in most of the patients.
  European Journal of Intensive Care Medicine 10/2010; 36(10):1681-7. · 5.17 Impact Factor
• Source

  Available from: Line Falaize

  Article: Impact of tracheostomy on swallowing performance in Duchenne muscular dystrophy.

  Nicolas Terzi, Hélène Prigent, Michèle Lejaille, Line Falaize, Djillali Annane, David Orlikowski, Frédéric Lofaso
  [show abstract] [hide abstract]
  ABSTRACT: Mechanical ventilation has improved survival in patients with Duchenne muscular dystrophy (DMD). Over time, these patients experience upper airway dysfunction, swallowing impairments, and dependency on the ventilator that may require invasive mechanical ventilation via a tracheostomy. Tracheostomy is traditionally believed to further impair swallowing. We assessed swallowing performance and breathing-swallowing interactions before and after tracheostomy in 7 consecutive wheelchair-bound DMD patients, aged 25+/-4 years, over a 4-year period. Chin electromyography, laryngeal motion, and inductive respiratory plethysmography recordings were obtained during swallowing of three water-bolus sizes in random order. Piecemeal deglutition occurred in all patients over several breathing cycles. Half the swallows were followed by inspiration before tracheostomy. Total bolus swallowing time was significantly shorter (P=0.009), and the number of swallows per bolus significantly smaller (P=0.01), after than before tracheostomy. Invasive ventilation via a tracheostomy may improve swallowing.
  Neuromuscular Disorders 08/2010; 20(8):493-8. · 2.80 Impact Factor
• Article: Toll motorway accessibility for wheelchair users: a survey.

  Hélène Prigent, Nicolas Roche, Bruno Guillon, Anne Hurand, Bernadette Moreau, Jean Pierre Dufresne, Jean-François Ravaud, Frédéric Lofaso
  [show abstract] [hide abstract]
  ABSTRACT: To identify difficulties encountered by wheelchair users who travel on toll motorways, with the goal of defining areas for improvement. Survey. After observing a wheelchair user travelling on a toll motorway and using the associated services, we designed a self-questionnaire on perceptions by wheelchair users of toll motorway accessibility. Toll motorway and rehabilitation hospital in France. We recruited 167 wheelchair users by advertisement and, to assess selection bias, 19 consecutive outpatients who visited our hospital's wheelchair showroom. None. Of the 186 included subjects, 91 (49%) were used to driving independently on toll motorways. Among them, only 16% used automatic toll booths and 32% reported difficulties at toll booths. Furthermore, 53% routinely asked for help at filling stations, and only 27% were aware of the availability of a free-of-charge assistance service for disabled people at some filling stations. Among the 186 toll motorway users, only 84 (45%) reported never encountering difficulties in lay-bys; 162 (87%) felt that toilet accessibility was the most important feature of lay-bys and 143 (77%) preferred the locked toilets reserved for disabled people.Conclusion: Wheelchair users reported difficulties on toll motorways that could be corrected fairly easily.
  Clinical Rehabilitation 10/2008; 22(9):812-5. · 2.12 Impact Factor
• Article: Sniff and Muller manoeuvres to measure diaphragmatic muscle strength.

  Hélène Prigent, David Orlikowski, Christophe Fermanian, Michèle Lejaille, Line Falaize, Alain Louis, Brigitte Fauroux, Frédéric Lofaso
  [show abstract] [hide abstract]
  ABSTRACT: We hypothesized that peak values of oesophageal (Poes) and transdiaphragmatic pressure (Pdi) swings during a maximal sniff manoeuvre and a maximal static inspiratory manoeuvre (Muller manoeuvre) are comparable or give complementary information for assessing diaphragmatic and global inspiratory muscle strength. We studied 98 patients with suspected diaphragmatic dysfunction. Poes and Pdi swings were measured during maximal sniff manoeuvres (sniff), maximal Muller manoeuvres (max), and cervical magnetic phrenic nerve stimulation (cervical Tw). Eighty eight patients were able to perform both volitional manoeuvres. Among them, mean Poes sniff was significantly higher than mean Poes max (48.7+/-28.7 cm H(2)O vs. 42.9+/-27.4 cm H(2)O, p<0.05) and mean Pdi sniff was higher than mean Pdi max (49.2+/-35.1cm H(2)O vs. 42.9+/-33.3 cm H(2)O, respectively, p=0.05). Cervical Pdi Tw correlated better with Pdi sniff (p<0.0001, r=0.62) than with Pdi max (p<0.0001, r=0.44). Poes and Pdi swings were greatest during the sniff manoeuvre in 42 patients (48%) and during the Muller manoeuvre in 29 patients (33%). Among the 17 remaining patients, nine had the greatest Poes swing during a maximal sniff manoeuvre and the greatest Pdi swing during a maximal static inspiratory manoeuvre; the opposite occurred in the other eight patients. The combination of Muller manoeuvre and sniff manoeuvre increased the diagnosis of normal diaphragmatic strength from 18 patients (20%) to 21 patients (24%), and the additional analysis of cervical Pdi Tw further increased the diagnosis of normal diaphragmatic strength to 27 patients (31%). In conclusion, though sniff manoeuvre gave significantly higher values than Muller manoeuvre, both volitional manoeuvres and cervical Pdi Tw are complementary and should be used in combination to evaluate diaphragmatic muscle strength.
  Respiratory medicine 08/2008; 102(12):1737-43. · 2.33 Impact Factor
• Source

  Available from: rtjournalonline.com

  Article: Noninvasive ventilation as an alternative to endotracheal intubation during tracheotomy in advanced neuromuscular disease.

  David Orlikowski, Hélène Prigent, Jésus Gonzales-Bermejo, Philippe Aubert, Frédéric Lofaso, Jean Claude Raphael, Bernard Clair
  [show abstract] [hide abstract]
  ABSTRACT: To compare conventional tracheotomy with endotracheal intubation to tracheotomy with noninvasive positive-pressure ventilation (NPPV) in advanced neuromuscular disease. This was a retrospective study of a historical cohort of patients tracheotomized while sedated and intubated versus patients tracheotomized under NPPV and local anesthesia. We recorded previous intubation difficulties, complications (eg, aspiration pneumonia), and hospital stay. Conventional tracheotomy was performed in 7 patients. We performed tracheotomy during NPPV with local anesthesia in 13 patients. All but 3 patients had risk factors for difficult intubation. Hospital stay was 23.3 +/- 10.3 d in the conventional group and 25.3 +/- 12.9 d in the NPPV group (p = 0.87). The number of pneumonias was higher in the conventional-tracheotomy group (4 vs 1, p = 0.03). In neuromuscular patients, performing tracheotomy with NPPV and local anesthesia may help avoid endotracheal intubation and reduce morbidity.
  Respiratory care 01/2008; 52(12):1728-33. · 2.01 Impact Factor
• Article: [Home ventilation in neuromuscular patients.]

  David Orlikowski, Hélène Prigent, Jésus Gonzalez, Tarek Sharshar, Frédéric Lofaso, Jean Claude Raphael
  [show abstract] [hide abstract]
  ABSTRACT: Long term domiciliary mechanical ventilation in patients with neuromuscular disease (indications, establishment and follow up) Neuromuscular diseases represent a heterogeneous group of pathologies of which the common feature is the development of a restrictive ventilatory failure. Background. Respiratory insufficiency of neuromuscular origin manifests itself by functional symptoms that must be carefully searched for in the history, such as headaches, sleep disorders, or dyspnoea of effort, sometimes very mild, or in severe cases associated with orthopnoea. Follow up should be multi-disciplinary. On the respiratory level regular measurement of blood gases, vital capacity, maximum inspiratory and expiratory pressures as well as sleep studies, will detect the criteria for mechanical ventilation ( hypercarbia > 45 mm Hg, nocturnal desaturation < 88%, vital capacity < 60%, PI max < 60 cm H2O). Viewpoint. The establishment of mechanical ventilation is a major decision for patients with neuromuscular disease because of the important physical, psychological, social and sometimes financial consequences. The patients and their family must be instructed precisely in order to obtain the best possible observation and compliance. The establishment requires a stay in hospital of several days to optimise the choice of ventilator, its settings, and connections. The link with the organisation managing the domiciliary ventilation is fundamental in ensuring follow up after discharge from hospital. Techniques of cough assistance must be taught to each neuromuscular patient requiring mechanical ventilation. Conclusion. Ventilation of neuromuscular patients requires careful evaluation of the indications and rigorous follow up by a multidisciplinary team with wide experience of this type of disease. Key words: vital capacity; ventilation; neuromuscular diseases Rev Mal Respir advance online publication, Day Month Year; 05 07 2005 doi:10.1019/200530096.
  Revue des Maladies Respiratoires 07/2005; · 0.59 Impact Factor
• Article: Demonstration of a second rapidly conducting cortico-diaphragmatic pathway in humans.

  Tarek Sharshar, Nicholas S Hopkinson, Sophie Jonville, Hélène Prigent, Robert Carlier, Mark J Dayer, Elisabeth B Swallow, Frédéric Lofaso, John Moxham, Michael I Polkey
  [show abstract] [hide abstract]
  ABSTRACT: Functional imaging studies in normal humans have shown that the supplementary motor area (SMA) and the primary motor cortex (PMC) are coactivated during various breathing tasks. It is not known whether a direct pathway from the SMA to the diaphragm exists, and if so what properties it has. Using transcranial magnetic stimulation (TMS) a site at the vertex, representing the diaphragm primary motor cortex, has been identified. TMS mapping revealed a second area 3 cm anterior to the vertex overlying the SMA, which had a rapidly conducting pathway to the diaphragm (mean latency 16.7 +/- 2.4 ms). In comparison to the vertex, the anterior position was characterized by a higher diaphragm motor threshold, a greater proportional increase in motor-evoked potential (MEP) amplitude with voluntary facilitation and a shorter silent period. Stimulus-response curves did not differ significantly between the vertex and anterior positions. Using paired TMS, we also compared intracortical inhibition/facilitation (ICI/ICF) curves. In comparison to the vertex, the MEP elicited from the anterior position was not inhibited at short interstimulus intervals (1-5 ms) and was more facilitated at long interstimulus intervals (9-20 ms). The patterns of response were identical for the costal and crural diaphragms. We conclude that the two coil positions represent discrete areas that are likely to be the PMC and SMA, with the latter wielding a more excitatory effect on the diaphragm.
  The Journal of Physiology 12/2004; 560(Pt 3):897-908. · 4.72 Impact Factor
• Source

  Available from: PubMed Central

  Article: Science review: mechanisms of impaired adrenal function in sepsis and molecular actions of glucocorticoids.

  Hélène Prigent, Virginie Maxime, Djillali Annane
  [show abstract] [hide abstract]
  ABSTRACT: This review describes current knowledge on the mechanisms that underlie glucocorticoid insufficiency in sepsis and the molecular action of glucocorticoids. In patients with severe sepsis, numerous factors predispose to glucocorticoid insufficiency, including drugs, coagulation disorders and inflammatory mediators. These factors may compromise the hypothalamic-pituitary axis (i.e. secondary adrenal insufficiency) or the adrenal glands (i.e. primary adrenal failure), or may impair glucocorticoid access to target cells (i.e. peripheral tissue resistance). Irreversible anatomical damages to the hypothalamus, pituitary, or adrenal glands rarely occur. Conversely, transient functional impairment in hormone synthesis may be a common complication of severe sepsis. Glucocorticoids interact with a specific cytosolic glucocorticoid receptor, which undergoes conformational changes, sheds heat shock proteins and translocates to the nucleus. Glucocorticoids may also interact with membrane binding sites at the surface of the cells. The molecular action of glucocorticoids results in genomic and nongenomic effects. Direct and indirect transcriptional and post-transcriptional effects related to the cytosolic glucocorticoid receptor account for the genomic effects. Nongenomic effects are probably subsequent to cytosolic interaction between the glucocorticoid receptor and proteins, or to interaction between glucocorticoids and specific membrane binding sites.
  Critical care (London, England) 09/2004; 8(4):243-52. · 4.61 Impact Factor
• Article: Optimization of power wheelchair control for patients with severe Duchenne muscular dystrophy.

  Nadine Pellegrini, Bruno Guillon, Hélène Prigent, Michel Pellegrini, David Orlikovski, Jean-Claude Raphael, Frédéric Lofaso
  [show abstract] [hide abstract]
  ABSTRACT: The extended survival of patients with Duchenne muscular dystrophy (DMD) achieved by the introduction of mechanical ventilation is raising new quality-of-life issues. We evaluated passive range of wrist extension, key pinch strength, and power wheelchair driving in 84 patients. The 47 drivers with restricted driving abilities were older than the 37 unrestricted drivers (27.2+/-5.0 y vs. 22.8+/-3.8 y) and had worse upper limb performance. By multiple logistic regression, only key pinch was significant ( R(2) = 0.224, P = 0.02. Eighteen restricted drivers were reassessed after having swapped a conventional joystick for another control system (mini-joystick, isometric mini-joystick, finger joystick, or pad) and having moved the position of the tested control system so that the patient could use it with different fingers, his chin or his mouth. All of them regained the ability to drive unrestricted. Adults with DMD gradually lose their ability to drive with a conventional joystick but can regain unrestricted driving with alternative control systems.
  Neuromuscular Disorders 06/2004; 14(5):297-300. · 2.80 Impact Factor
• Article: Assessing inspiratory muscle strength by sniff nasal inspiratory pressure.

  Hélène Prigent, Michèle Lejaille, Line Falaize, Alain Louis, Maria Ruquet, Brigitte Fauroux, Jean Claude Raphael, Frédéric Lofaso
  [show abstract] [hide abstract]
  ABSTRACT: The sniff nasal inspiratory pressure (SNIP) consists in the measurement of pressure through an occluded nostril during sniffs performed through the controlateral nostril. It is an accurate and noninvasive approximation of esophageal pressure swing during sniff maneuvers. However SNIP can underestimate esophageal pressure swing in subjects with nasal obstruction, patients with chronic obstructive pulmonary disease and severe neuromuscular patients. Nevertheless, since SNIP maneuver has predicted normal values, is noninvasive and is easier to perform than maximal inspiratory pressure (MIP) maneuver, it could be considered as the first simple test to use in order to assess inspiratory muscle weakness. In addition, because it is as reproducible as MIP, it can be suitable to follow inspiratory muscle function in chronic neuromuscular patients. Because, of the important limit of agreement between SNIP and MIP, these two methods are not interchangeable but complementary.
  Neurocritical Care 02/2004; 1(4):475-8. · 2.47 Impact Factor
• Article: Respiratory dysfunction in Guillain-Barré Syndrome.

  David Orlikowski, Hélène Prigent, Tarek Sharshar, Frédéric Lofaso, Jean Claude Raphael
  [show abstract] [hide abstract]
  ABSTRACT: Guillain-Barré Syndrome is the leading cause of nontraumatic acute paralysis in industrialized countries. About 30% of patients have respiratory failure requiring intensive care unit (ICU) admission and invasive mechanical ventilation. Progressive weakness of both the inspiratory and the expiratory muscles is the mechanism leading to respiratory failure. Aspiration pneumonia and atelectasis are common consequences of the bulbar muscle weakness and ineffective cough. The classical signs of respiratory distress occur too late to serve as guidelines for management, and measurements of vital capacity and static respiratory pressures are useful to determine the best times for starting and stopping mechanical ventilation. Several factors present at admission and during the ICU stay are known to predict a need for invasive mechanical ventilation. They include rapidly progressive motor weakness, involvement of both the peripheral limb and the axial muscles, ineffective cough, bulbar muscle weakness, and a rapid decrease in vital capacity. Specific treatments (plasma exchange and intravenous immunoglobulins) have decreased both the number of patients requiring ventilation and the duration of ventilation. The need for mechanical ventilation is associated with residual functional impairments, although all patients eventually recover normal respiratory muscle function.
  Neurocritical Care 02/2004; 1(4):415-22. · 2.47 Impact Factor