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ABSTRACT: Introduction: Patients with the congenital central hypoventilation syndrome (CCHS) suffer from life-threatening hypoventilation when asleep, making them dependent on mechanical ventilation (MV) at night or during naps. State-of-art respiratory management consists of intermittent positive-pressure ventilation via a tracheotomy or mask. In some patients hypoventilation is permanent, in which case ventilatory support must be extended to the waking hours. Diaphragm pacing can prove useful in such situations.
Methods and results: This report describes the case of a 26-year-old woman with CCHS in whom failure to achieve adequate MV led to life-threatening pulmonary hypertension (PH), with a systolic pulmonary artery pressure (PAP) of 80 mmHg and right ventricular hypertrophy, despite optimization of all possible measures and despite extensive therapeutic education efforts. Diaphragm pacing using laparoscopically implanted intradiaphragmatic phrenic nerve stimulation electrodes corrected alveolar hypoventilation and lastingly reversed PH (systolic PAP below 40 mmHg after 2 months, sustained after 2 years). Diaphragm pacing induced shoulder pain, however, involving the chronic use of analgesics. The pacing had to be stopped for tolerance reasons after two years, leading to PH worsening and the need for diurnal MV.
Conclusions: Diaphragm pacing appears likely effective to restore alveolar ventilation and reverse PH in adult CCHS patients.
The International journal of artificial organs 05/2013; · 1.86 Impact Factor
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ABSTRACT: Rationale: Diaphragmatic insults occurring during intensive care unit (ICU) stays have become the focus of intense research. However, diaphragmatic abnormalities at the initial phase of critical illness remain poorly documented in humans. Objective: To determine the incidence, risk factors, and prognostic impact of diaphragmatic impairment on ICU admission. Methods: Prospective, six-month, observational cohort study in two ICUs. Mechanically ventilated patients were studied within 24 hours following intubation (day-1) and 48 hrs later (day-3). Seventeen anesthetized intubated control anesthesia patients were also studied. The diaphragm was assessed by twitch tracheal pressure (Ptr,stim) in response to bilateral anterior magnetic phrenic nerve stimulation. Main Results: Eighty-five consecutive patients aged 62 [54-75] (median [interquartile range]) were evaluated (medical admission 79%; SAPS II, 54 [44-68]). On day 1, Ptr,stim was 8.2 [5.9-12.3] cmH2O and 64% of patients had Ptr,stim <11cmH2O. Independent predictors of low Ptr,stim were sepsis (linear regression coefficient, -3.74; standard error, 1.16; p = 0.002) and SAPS II (linear regression coefficient, -0.07; standard error, 1.69; p = 0.03). Compared to non-survivors, ICU survivors had higher Ptr,stim (9.7 [6.3-13.8] vs. 7.3 [5.5-9.7] cmH2O, p=0.004). This was also true for hospital survivors vs. non-survivors (9.7 [6.3-13.5] vs. 7.8 [5.5-10.1] cmH2O, p=0.004). Day 1 and day 3 Ptr,stim were similar. Conclusions: A reduced capacity of the diaphragm to produce inspiratory pressure (diaphragm dysfunction) is frequent upon ICU admission. It is associated with sepsis and disease severity, suggesting that it may represent another form of organ failure. It is associated with a poor prognosis.
American Journal of Respiratory and Critical Care Medicine 05/2013; · 11.08 Impact Factor
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ABSTRACT: CONTEXT: Pressure support ventilation (PSV) must be tailored to the load capacity balance of the respiratory system. While "over assistance" generated hyperinflation and ineffective efforts, "under assistance" increased respiratory drive and causes dyspnea. Surface electromyograms (sEMGs) of extradiaphragmatic inspiratory muscles were responsive to respiratory loading/unloading. OBJECTIVES: To determine if sEMGs of extradiaphragmatic inspiratory muscles vary with PSV settings and relate to the degree of discomfort and the intensity of dyspnea in acutely ill patients. DESIGN: Pathophysiological study, prospective inclusions of 12 intubated adult patients. INTERVENTIONS: Two PSV levels (high and low) and two expiratory trigger (ET) levels (high and low). MEASUREMENTS: Surface electromyograms of the scalene, parasternal, and Alae Nasi muscles (peak, EMGmax; area under the curve, EMGAUC); dyspnea visual analogue scale (VAS); prevalence of ineffective triggering efforts. MAIN RESULTS: For the three recorded muscles, EMGmax and EMGAUC were significantly greater with low PS than high PS. The influence of ET was less important. A strong correlation was found between dyspnea and EMGmax. A significant inverse correlation was found between the prevalence of ineffective efforts and both dyspnea-VAS and EMGmin. CONCLUSIONS: Surface electromyograms of extradiaphragmatic inspiratory muscles provides a simple, reliable and non-invasive indicator of respiratory muscle loading/unloading in mechanically ventilated patients. Because this EMG activity is strongly correlated to the intensity of dyspnea, it could be used as a surrogate of respiratory sensations in mechanically ventilated patients, and might, therefore, provide a monitoring tool in patients in whom detection and quantification of dyspnea is complex if not impossible.
European Journal of Intensive Care Medicine 04/2013; · 5.17 Impact Factor
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ABSTRACT: NIV adherence ('quantity' of ventilation) has a prognostic impact in amyotrophic lateral sclerosis (ALS). We hypothesized that NIV effectiveness ('quality') could also have a similar impact. NIV effectiveness was evaluated in 82 patients within the first month (M1) and every three months (symptoms, arterial blood bases, and nocturnal pulsed oxygen saturation - SpO2). Kaplan-Meier survival and risk factors for mortality one year after NIV initiation were evaluated. Forty patients were considered 'correctly ventilated' at M1 (Group 1, less than 5% of nocturnal oximetry time with an SpO2<90% - TS90) while 42 were not (Group 2). Both groups were comparable in terms of respiratory and neurological baseline characteristics. Survival was better in Group 1 (75% survival at 12 months) than in Group 2 (43% survival at 12 months, p = 0.002). In 12 Group 2 patients corrective measures were efficient in correcting TS90 at six months. In this subgroup, one-year mortality was not different from that in Group 1. Multivariate analysis identified independent mortality risk factors expectedly including bulbar involvement (HR = 4.31 (1.73 - 10.76), p = 0.002), 'rapid respiratory decline' (HR = 3.55 (1.29 - 9.75), p = 0.014) and vital capacity (HR = 0.97 (0.95 - 0.99), p = 0.010), but also inadequate ventilation in the first month (HR = 2.32 (1.09 - 4.94), p = 0.029). In conclusion, in ALS patients NIV effectiveness to correct nocturnal desaturations is an independent prognostic factor.
Amyotrophic lateral sclerosis and frontotemporal degeneration. 03/2013;
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ABSTRACT: PURPOSE: To compare breathing pattern descriptors and diaphragm electromyographic activity (EAdi)-derived indices obtained from a neurally adjusted ventilatory assist catheter during a spontaneous breathing trial (SBT) in patients successfully and unsuccessfully separated from the ventilator and to assess their performance as a potential marker to discriminate these two categories of patients. METHODS: Fifty-seven ready-to-wean patients were included in a prospective observational study. During a 30-min SBT (pressure support 7 cmH(2)O, zero end expiratory pressure), tidal volume (V (T)) and respiratory rate (RR) were obtained from the flow signal at baseline and at 3, 10, 20 and 30 min during the SBT. EAdi-derived indices were simultaneously computed: maximum of the EAdi (EAdi(max)), area under the inspiratory curve of EAdi (EAdi(AUC)), the difference between EAdi(max) and EAdi(min) (∆EAdi), EAdi(max)/V (T), EAdi(AUC)/V (T) and ∆EAdi/V (T). Patients, successfully (success group; n = 35) and unsuccessfully (failure group; n = 22) separated from the ventilator were compared. RESULTS: At baseline, the breathing pattern was similar in the two groups, whereas EAdi(max) and EAdi(AUC) were significantly lower in the success group (p < 0.05). In the failure group, RR and RR/V (T) increased significantly during the trial, V (T) decreased, whereas EAdi(max) and EAdi(AUC) did not change. At 3 min, the areas under the receiver operating characteristic-curve of RR/V (T) and the EAdi-derived indices to predict weaning outcome were 0.83 for the rapid shallow breathing index (RSBI), 0.84 for EAdi(max)/V (T) , 0.80 for EAdi(AUC)/V (T) (0.80) and 0.82 for ∆EAdi/V (T). The coefficient of variation for V (T) decreased in the failure group while that for EAdi(max) remained unchanged. CONCLUSIONS: EAdi-derived indices provide reliable and early predictors of weaning outcome. However, the performance of these indices is not better than the RR/V (T).
European Journal of Intensive Care Medicine 09/2012; · 5.17 Impact Factor
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ABSTRACT: The automatic ventilatory drive in amphibians depends on two oscillators interacting with each other, the gill/buccal and lung oscillators. The lung oscillator would be homologous to the mammalian pre-Bötzinger complex and the gill/buccal oscillator homologous to the mammalian parafacial respiratory group/retrotrapezoid nucleus (pFRG/RTN). Dysfunction of the pFRG/RTN has been involved in the development of respiratory diseases associated to the loss of CO(2) chemosensitivity such as the congenital central hypoventilation syndrome. Here, on adult in vitro isolated frog brainstem, consequences of the buccal oscillator inhibition (by reducing Cl(-)) were evaluated on the respiratory rhythm developed by the lung oscillator under hypercapnic challenges. Our results show that under low Cl(-) concentration (i) the buccal oscillator is strongly inhibited and the lung burst frequency and amplitude decreased and (ii) it persists a powerful CO(2) chemosensitivity. In conclusion, in frog, the CO(2) chemosensitivity depends on cellular contingent(s) whose the functioning is independent of the concentration of Cl(-) and origin remains unknown.
Respiratory Physiology & Neurobiology 07/2012; 183(2):166-9. · 2.24 Impact Factor
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European Respiratory Journal 07/2012; 40(1):276-8. · 5.89 Impact Factor
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ABSTRACT: To compare the respective impact of pressure support ventilation and naturally adjusted ventilatory assist, with and without a noninvasive mechanical ventilation algorithm, on patient-ventilator interaction.
Prospective 2-month study.
Adult critical care unit in a tertiary university hospital.
Seventeen patients receiving a prophylactic postextubation noninvasive mechanical ventilation.
Patients were randomly mechanically ventilated for 10 mins with: pressure support ventilation without a noninvasive mechanical ventilation algorithm (PSV-NIV-), pressure support ventilation with a noninvasive mechanical ventilation algorithm (PSV-NIV+), neurally adjusted ventilatory assist without a noninvasive mechanical ventilation algorithm (NAVA-NIV-), and neurally adjusted ventilatory assist with a noninvasive mechanical ventilation algorithm (NAVA-NIV+).
Breathing pattern descriptors, diaphragm electrical activity, leak volume, inspiratory trigger delay, inspiratory time in excess, and the five main asynchronies were quantified. Asynchrony index and asynchrony index influenced by leaks were computed. Peak inspiratory pressure and diaphragm electrical activity were similar for each of the four experimental conditions. For both pressure support ventilation and neurally adjusted ventilatory assist, the noninvasive mechanical ventilation algorithm significantly reduced the level of leakage (p < .01). Inspiratory trigger delay was not affected by the noninvasive mechanical ventilation algorithm but was shorter in neurally adjusted ventilatory assist than in pressure support ventilation (p < .01). Inspiratory time in excess was shorter in neurally adjusted ventilatory assist and PSV-NIV+ than in PSV-NIV- (p < .05). Asynchrony index was not affected by the noninvasive mechanical ventilation algorithm but was significantly lower in neurally adjusted ventilatory assist than in pressure support ventilation (p < .05). Asynchrony index influenced by leaks was insignificant with neurally adjusted ventilatory assist and significantly lower than in pressure support ventilation (p < .05). There was more double triggering with neurally adjusted ventilatory assist.
Both neurally adjusted ventilatory assist and a noninvasive mechanical ventilation algorithm improve patient-ventilator synchrony in different manners. NAVA-NIV+ offers the best compromise between a good patient-ventilator synchrony and a low level of leaks. Clinical studies are required to assess the potential clinical benefit of neurally adjusted ventilatory assist in patients receiving noninvasive mechanical ventilation.
Clinicaltrials.gov Identifier NCT01280760.
Critical care medicine 06/2012; 40(6):1738-44. · 6.37 Impact Factor
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ABSTRACT: The neural structures responsible for the coupling between ventilatory control and pulmonary gas exchange during exercise have not been fully identified. Suprapontine mechanisms have been hypothesized but not formally evidenced. Because the involvement of a premotor circuitry in the compensation of inspiratory mechanical loads has recently been described, we looked for its implication in exercise-induced hyperpnea.
Electroencephalographical recordings were performed to identify inspiratory premotor potentials (iPPM) in eight physically fit normal men during cycling at 40 and 70% of their maximal oxygen consumption ((V)·O(2max) ). Relaxed pedalling (0 W) and voluntary sniff manoeuvres were used as negative and positive controls respectively.
Voluntary sniffs were consistently associated with iPPMs. This was also the case with voluntarily augmented breathing at rest (in three subjects tested). During the exercise protocol, no respiratory-related activity was observed whilst performing bouts of relaxed pedalling. Exercise-induced hyperpnea was also not associated with iPPMs, except in one subject.
We conclude that if there are cortical mechanisms involved in the ventilatory adaptation to exercise in physically fit humans, they are distinct from the premotor mechanisms activated by inspiratory load compensation.
Acta Physiologica 02/2012; 205(3):356-62. · 3.09 Impact Factor
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ABSTRACT: The aim of this work was to determine whether survival changed during 2002-2009 at a French amyotrophic lateral sclerosis (ALS) center. We included all patients with ALS who were seen consecutively at the center from January 2002-May 2009. Participants were followed from date of first visit through death, date of censoring, or December 31, 2009, whichever occurred first. Cox proportional hazard models computed hazard ratios (HR; 95% confidence interval CI) of death, and flexible modeling of continuous predictors (splines) assessed trends in survival. We analyzed a total of 2,037 ALS patients, of whom 1,471 died before the end of follow-up. Median survival was 2.83 years from onset and 1.65 years from first visit. Compared to patients first seen before 2004, the HR of death was 0.97 (95% CI = 0.85-1.11, p = 0.6721) for patients first seen in 2004-2005, 0.96 (95% CI = 0.83-1.10, p = 0.5125) for 2006-2007, and 0.56 (95% CI = 0.46-0.69, p < 0.0001) after 2007, while adjusting for other survival predictors. Spline analysis confirmed that survival remained stable during 2002-2006, then markedly improved. The proportion of patients receiving non-invasive ventilation (NIV) increased from 16 (2004) to 51% (2008). At this large ALS center, survival improved after 2006. Because more aggressive use of NIV was the principal therapeutic adaptation, our data suggest that better survival resulted from improved respiratory care.
Journal of Neurology 01/2012; 259(9):1788-92. · 3.47 Impact Factor
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Jesus Gonzalez-Bermejo,
Capucine Morélot-Panzini,
François Salachas,
Stefania Redolfi,
Christian Straus,
Marie-Hélène Becquemin,
Isabelle Arnulf,
Pierre-François Pradat,
Gaëlle Bruneteau,
Anthony R Ignagni,
Moustapha Diop,
Raymond Onders,
Teresa Nelson,
Fabrice Menegaux,
Vincent Meininger, Thomas Similowski
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ABSTRACT: In amyotrophic lateral sclerosis (ALS) patients, respiratory insufficiency is a major burden. Diaphragm conditioning by electrical stimulation could interfere with lung function decline by promoting the development of type 1 muscle fibres. We describe an ancillary study to a prospective, non-randomized trial (NCT00420719) assessing the effects of diaphragm pacing on forced vital capacity (FVC). Sleep-related disturbances being early clues to diaphragmatic dysfunction, we postulated that they would provide a sensitive marker. Stimulators were implanted laparoscopically in the diaphragm close to the phrenic motor point in 18 ALS patients for daily conditioning. ALS functioning score (ALSFRS), FVC, sniff nasal inspiratory pressure (SNIP), and polysomnographic recordings (PSG, performed with the stimulator turned off) were assessed before implantation and after four months of conditioning (n = 14). Sleep efficiency improved (69 ± 15% to 75 ± 11%, p = 0.0394) with fewer arousals and micro-arousals. This occurred against a background of deterioration as ALSFRS-R, FVC, and SNIP declined. There was, however, no change in NIV status or the ALSFRS respiratory subscore, and the FVC decline was mostly due to impaired expiration. Supporting a better diaphragm function, apnoeas and hypopnoeas during REM sleep decreased. In conclusion, in these severe patients not expected to experience spontaneous improvements, diaphragm conditioning improved sleep and there were hints at diaphragm function changes.
Amyotrophic Lateral Sclerosis 01/2012; 13(1):44-54. · 3.40 Impact Factor
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ABSTRACT: Electrical stimulation can enhance muscle function. We applied repetitive cervical magnetic phrenic stimulation (rCMS) to induce diaphragm contractions in 7 healthy subjects (800 ms trains; transdiaphragmatic pressure (Pdi) measurements; tolerance ratings). Each rCMS train produced a sustained diaphragm contraction. Sixty-five percent of the maximal available output at 15 Hz proved the best compromise between Pdi and discomfort with nonfatiguing contractions. rCMS appears feasible and should be investigated for diaphragm conditioning in appropriate clinical populations.
Applied Physiology Nutrition and Metabolism 12/2011; 36(6):1001-8. · 2.13 Impact Factor
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ABSTRACT: Retrospective study of prospectively collected data to assess the reliability of cervical magnetic stimulation (CMS) to detect prolonged phrenic nerve (PN) conduction time at the bedside. Because PN injuries may cause diaphragm dysfunction, their diagnosis is relevant in intensive care units (ICU). This is achieved by studying latency and amplitude of diaphragm response to PN stimulation. Electrical stimulation (ES) is the gold standard, but it is difficult to perform in the ICU. CMS is an easy noninvasive tool to assess PN integrity, but co-activates muscles that could contaminate surface chest electromyographic recordings.
In a first set of 56 ICU patients with suspected PN injury, presence and latency of compound motor action potentials elicited by CMS and ES were compared. With ES as the reference method, CMS was evaluated as a test designed to indicate presence or absence of PN injury. In eight additional patients, intramuscular diaphragm recordings were compared with surface diaphragm recordings and with the electromyograms of possible contamination sources.
The sensitivity of CMS to diagnose abnormal PN conduction was 0.91, and specificity was 0.84, whereas positive and negative predictive values were 0.81 and 0.92, respectively. Passing-Bablok regression analysis suggested no differences between the two measures. The correlation between PN latency in response to CMS and ES was significant. The "diaphragm surface" and "needle" latencies were close, and were significantly different from those of possibly contaminating muscles. One hemidiaphragm showed likely signal contamination.
CMS provides an easy reliable tool to detect prolonged PN conduction time in the ICU.
European Journal of Intensive Care Medicine 12/2011; 37(12):1962-8. · 5.17 Impact Factor
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ABSTRACT: Fluid accumulation in the legs and its overnight redistribution into the neck appears to play a causative role in obstructive sleep apnea (OSA) in sedentary men. Chronic venous insufficiency (CVI) promotes fluid accumulation in the legs that can be counteracted by compression stockings.
To test the hypotheses that, in nonobese subjects with CVI and OSA, wearing compression stockings during the day will attenuate OSA by reducing the amount of fluid displaced into the neck overnight.
Nonobese subjects with CVI and OSA were randomly assigned to 1 week of wearing compression stockings or to a 1-week control period without compression stockings, after which they crossed over to the other arm. Polysomnography and measurement of overnight changes in leg fluid volume and neck circumference were performed at baseline and at the end of compression stockings and control periods.
Twelve subjects participated. Compared with the end of the control period, at the end of the compression stockings period there was a 62% reduction in the overnight leg fluid volume change (P = 0.001) and a 60% reduction in the overnight neck circumference increase (P = 0.001) in association with a 36% reduction in the number of apneas and hypopneas per hour of sleep (from 48.4 ± 26.9 to 31.3 ± 20.2, P = 0.002).
Redistribution of fluid from the legs into the neck at night contributes to the pathogenesis of OSA in subjects with CVI. Prevention of fluid accumulation in the legs during the day, and its nocturnal displacement into the neck, attenuates OSA in such subjects.
American Journal of Respiratory and Critical Care Medicine 08/2011; 184(9):1062-6. · 11.08 Impact Factor
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ABSTRACT: Patients suffering from congenital central hypoventilation syndrome (CCHS) depend on mechanical ventilation during sleep, from birth and throughout life. They lack CO₂-chemosensitivity. Hope has recently been raised by serendipitous observations of chemosensitivity recovery under treatment by desogestrel, a very potent progestin (Straus et al., 2010). Caution is however needed, because this effect could depend on dose, idiosyncrasies, or be transient. Desogestrel should not be prescribed to CCHS patients with a respiratory purpose until the results of a pending clinical trial (clinicaltrials.gov. NCT01243697) are available.
Respiratory Physiology & Neurobiology 07/2011; 178(2):357-8. · 2.24 Impact Factor
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Christophe M Pison,
Noël J Cano,
Cécile Chérion,
Fabrice Caron,
Isabelle Court-Fortune,
Marie-Thérèse Antonini,
Jésus Gonzalez-Bermejo,
Lahouari Meziane,
Luis Carlos Molano,
Jean-Paul Janssens,
Frédéric Costes,
Bernard Wuyam, Thomas Similowski,
Boris Melloni,
Maurice Hayot,
Julie Augustin,
Catherine Tardif,
Hervé Lejeune,
Hubert Roth,
Claude Pichard
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ABSTRACT: In chronic respiratory failure (CRF), body composition strongly predicts survival.
A prospective randomised controlled trial was undertaken in malnourished patients with CRF to evaluate the effects of 3 months of home rehabilitation on body functioning and composition. 122 patients with CRF on long-term oxygen therapy and/or non-invasive ventilation (mean (SD) age 66 (10) years, 91 men) were included from eight respiratory units; 62 were assigned to home health education (controls) and 60 to multimodal nutritional rehabilitation combining health education, oral nutritional supplements, exercise and oral testosterone for 90 days. The primary endpoint was exercise tolerance assessed by the 6-min walking test (6MWT). Secondary endpoints were body composition, quality of life after 3 months and 15-month survival.
Mean (SD) baseline arterial oxygen tension was 7.7 (1.2) kPa, forced expiratory volume in 1 s 31 (13)% predicted, body mass index (BMI) 21.5 (3.9) kg/m2 and fat-free mass index (FFMI) 15.5 (2.4) kg/m2. The intervention had no significant effect on 6MWT. Improvements (treatment effect) were seen in BMI (+0.56 kg/m2, 95% CI 0.18 to 0.95, p=0.004), FFMI (+0.60 kg/m2, 95% CI 0.15 to 1.05, p=0.01), haemoglobin (+9.1 g/l, 95% CI 2.5 to 15.7, p=0.008), peak workload (+7.2 W, 95% CI 3.7 to 10.6, p<0.001), quadriceps isometric force (+28.3 N, 95% CI 7.2 to 49.3, p=0.009), endurance time (+5.9 min, 95% CI 3.1 to 8.8, p<0.001) and, in women, Chronic Respiratory Questionnaire (+16.5 units, 95% CI 5.3 to 27.7, p=0.006). In a multivariate Cox analysis, only rehabilitation in a per-protocol analysis predicted survival (HR 0.27, 95% CI 0.07 to 0.95, p=0.042).
Multimodal nutritional rehabilitation aimed at improving body composition increased exercise tolerance, quality of life in women and survival in compliant patients, supporting its incorporation in the treatment of malnourished patients with CRF. Clinical Trial number NCT00230984.
Thorax 06/2011; 66(11):953-60. · 6.84 Impact Factor
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ABSTRACT: This study tests the hypothesis that the surface electromyographic (EMG) activity of upper airway dilators would respond to inspiratory loading in a healthy humans model of ventilator trigger asynchrony. EMG activity was measured in levator alae-nasi, genioglossus, parasternal, scalene and diaphragm muscles in eight subjects. They breathed quietly through a face mask and then were connected to a mechanical ventilator. Recordings were performed during nasal breathing against negative pressure triggers (-2.5%, -5% and -10% of maximal inspiratory pressure) and during oro-nasal breathing with a "-10% trigger". Scalene, alae-nasi and genioglossus EMG activity level increased with the "-10% trigger". While no breathing route dependence was found in scalene, the significant increase was only found for nasal breathing in alae-nasi and for oro-nasal breathing in genioglossus. The dyspnea intensity was significantly correlated with the EMG activity level of these three muscles. Surface EMG of airway dilator muscles could be used as a complementary tool to assess inspiratory drive during mechanical ventilation.
Respiratory Physiology & Neurobiology 06/2011; 178(2):341-5. · 2.24 Impact Factor
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Andrew J E Seely,
Stuart A Kauffman,
Jason H T Bates,
Peter T Macklem,
Béla Suki,
John C Marshall,
Andriy I Batchinsky,
Jose Luis Perez-Velazquez,
Adam Seiver,
Carolyn McGregor, [......],
Martin G Frasch,
Christian Straus,
Leon Glass,
Paul J Godin,
John A Morris,
Daby Sow,
Vera Nenadovic,
Ryan C Arnold,
Patrick Norris,
J Randall Moorman
Journal of critical care 06/2011; 26(3):325-7. · 2.13 Impact Factor
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BJA British Journal of Anaesthesia 06/2011; · 4.24 Impact Factor
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ABSTRACT: Phrenic pacing is an alternative to positive-pressure ventilation in selected patients, mostly in cases of upper spinal cord injury. We evaluated results of phrenic pacing performed by video-assisted thoracic surgery (VATS).
Between 1997 and 2007, after complete neuromuscular investigations, 20 patients requiring full-time ventilation were selected for phrenic pacing (19 with posttraumatic tetraplegia and 1 with congenital central hypoventilation syndrome). Quadripolar cuff electrodes were fixed around each intrathoracic phrenic nerve via bilateral VATS. They were connected to a subcutaneous radiofrequency receiver coupled to an external radiofrequency transmitter. All patients participated in a reconditioning program beginning 2 weeks after implantation and continued until ventilatory weaning.
Phrenic pacing was successful in all cases. No intraoperative complications or perioperative mortality were observed. Intraoperative testing detected stimulation thresholds in 19 patients (range, 0.05-2.9 mA). Ventilatory weaning was obtained in 18 patients. Median diaphragm reconditioning time was 6 weeks (2 weeks-11 months). Reconditioning was still in process in a young woman and was not achieved in an elderly woman with a 4-year history of tetraplegia. All the patients weaned from mechanical ventilation reported improved quality of life. Failure or delay in recovery of effective diaphragm contraction was due to nonreversible amyotrophy.
VATS implantation of 4-pole electrodes around the intrathoracic phrenic nerve is a safe procedure. Ventilatory weaning correlates with the degree of diaphragmatic amyotrophy. Phrenic pacing, performed as soon as neurologic and orthopedic stabilization is achieved, is the most important prognostic factor for successful weaning.
The Journal of thoracic and cardiovascular surgery 05/2011; 142(2):378-83. · 3.41 Impact Factor
