A comparison of invasive versus noninvasive full-time mechanical ventilation in Duchenne muscular dystrophy.

The aim of this study was to compare morbidity and causes of death in a series of 42 Duchenne patients receiving full-time mechanical ventilation either by tracheostomy (TR, n = 16 or by noninvasive methods (noninvasive ventilation [NIV], n = 26). At inclusion for a 5-year observation period (2002-2006), TR and NIV patients were 32.7 and 27 years old, respectively. A program of follow-up with similar ventilation devices, techniques of respiratory physiotherapy, and drugs was applied to all the patients [TR + NIV]. Ages and respiratory characteristics at death and causes of death were comparable between groups. Morbidity was worse in TR compared with NIV patients; mucus hypersecretion and tracheal injuries were more frequent, whereas loss of weight and need for gastric feeding appeared less frequent in the TR group. Because noninvasive techniques avoid the severe complications associated with TR with comparable mortality, the authors support the use of noninvasive interfaces as default choice when assisted ventilation is required for daytime use.

Effect of non-invasive ventilation on respiratory muscle loading and endurance in patients with Duchenne muscular dystrophy.

BACKGROUND: Respiratory muscle weakness in patients with Duchenne muscular dystrophy (DMD) leads to respiratory failure for which non-invasive positive pressure ventilation (NIPPV) is an effective treatment. This is used initially at night (n-NIPPV) but, as the disease progresses, diurnal use (d-NIPPV) is often necessary. The connection between NIPPV and relief of respiratory muscle fatigue remains unclear. A study was undertaken to determine the extent to which n-NIPPV and d-NIPPV unload the respiratory muscles and improve respiratory endurance in patients with DMD. METHODS: Fifty patients with DMD were assessed at 20.00 and 08.00 h. More severely affected patients with nocturnal hypoventilation received n-NIPPV; those with daytime dyspnoea also received d-NIPPV via a mouthpiece (14.00-16.00 h). Lung function, modified Borg dyspnoea score, spontaneous breathing pattern, tension-time index (TT(0.1) = occlusion pressure (P(0.1))/maximum inspiratory pressure (MIP) x duty cycle (Ti/Ttot)) and respiratory muscle endurance time (Tlim) against a threshold load of 35% MIP were measured. RESULTS: More severe respiratory muscle weakness was associated with a higher TT(0.1) and lower Tlim. In contrast to non-dyspnoeic patients, patients with dyspnoea (Borg score > 2.5/10) showed an increase in Tlim and decrease in TT(0.1) after n-NIPPV. At 16.00 h, immediately after d-NIPPV, patients with dyspnoea had lower TT(0.1) and Borg scores with unchanged Tlim. Compared with the control day without d-NIPPV, TT(0.1), Borg scores and Tlim were all improved at 20.00 h. CONCLUSIONS: In patients with dyspnoea with DMD, the load on respiratory muscles increases and endurance capacity decreases with increasing breathlessness during the day, and this is reversed by n-NIPPV. An additional 2 h of d-NIPPV unloads respiratory muscles and reverses breathlessness more effectively than n-NIPPV alone.

Mechanical ventilation in Duchenne patients with chronic respiratory insufficiency: clinical implications of 20 years published experience.

Chronic respiratory insufficiency is inevitable in the course of disease progression in patients with Duchenne muscular dystrophy (DMD). Without mechanical ventilation (MV), morbidity and mortality are highly likely towards the end of the second decade of life. The present review reports evidence and clinical implications regarding DMD patients treated with MV. There is no doubt that nocturnal hypercapnia precedes daytime hypercapnia. Historical comparisons have provided evidence that non-invasive intermittent positive pressure ventilation (NIPPV) at night is effective and improves quality of life and survival by 5-10 years. By contrast, the optimal criteria and timing for initiation of NIPPV are inconsistent. A recent randomized study however demonstrated the benefits of commencing NIPPV as soon as nocturnal hypoventilation is detected (Ward S, et al., Randomised controlled trial of non-invasive ventilation (NIV) for nocturnal hypoventilation in neuromuscular and chest wall disease patients with daytime normocapnia. Thorax 2005; 60: 1019-24). The respective role of the three hypotheses of the indirect action of nocturnal NIPPV on daytime blood gases may be complimentary; the main improvement may be due to improved ventilatory response to CO2. The ultimate time to offer full time ventilation with the most advantageous interface is lacking in evidence. Full time NIV is possible with a combination of a nasal mask during the night and a mouthpiece during the day, however tracheostomy may be provided when mechanical techniques of cough-assistance are useless to treat chronic cough insufficiency.

Diurnal ventilation via mouthpiece: survival in end-stage Duchenne patients.

The present study aimed to assess the impact of diurnal mouthpiece intermittent positive pressure ventilation (MIPPV) as the extension of the nasal intermittent positive pressure ventilation (NIPPV) in Duchenne muscular dystrophy (DMD). In total, 42 DMD patients aged 15-33 yrs, normocapnic at night with NIPPV and receiving MIPPV since end-diurnal hypercapnia, were studied. Transcutaneous CO2 tension (Pt,CO2) was prospectively monitored at the end of the day, before and after MIPPV initiation. Vital capacity (VC), breathing pattern and maximal inspiratory strength were measured. Patients were asked to score the presence (1 point) or absence (0 point) of seven respiratory-linked symptoms before and after MIPPV establishment. Survival rates reached 88, 77, 58 and 51% after 1, 3, 5 and 7 yrs, respectively. The mean survival rate was 31 yrs. VC stabilised during 5 yrs with MIPPV. Symptom scores significantly decreased and Pt,CO2 normalised during the day (8.17 +/- 2.22 to 5.78 +/- 0.73 kPa). No accident and minor side-effects were observed in this 184 cumulated patient-yrs study. In conclusion, daytime mouthpiece ventilation is safe, prolongs survival and stabilises vital capacity in Duchenne muscular dystrophy patients. It is recommended on the condition that patients are equipped with a self-supporting harness.

Preoperative cardiopulmonary assessment in the child with neuromuscular scoliosis.

Preoperative cardiopulmonary assessment in the child with neuromuscular scoliosis comprises two successive steps. The first is the exclusion of any preoperative factor which could make the surgery too dangerous or unacceptable, unless corrected (e.g. clotting problems, decompensated cardiomyopathy, respiratory insufficiency, etc). The second is more functional, and consists of detecting potentially higher risks of postoperative alveolar hypoventilation and secretion removal insufficiency. The authors propose a logical decision-making tree, which can identify the most essential items. Preoperative assessment is a progressive evaluation of an acceptable or unacceptable cost-benefit ratio, which can best be achieved by spending time and discussing all aspects with the patient and family.

Tracheal versus noninvasive mechanical ventilation in neuromuscular patients: experience and evaluation.

From the experience of following 86 long-term ventilated neuromuscular patients, some aspects of the mode of ventilation are discussed: tolerance and problems, switching from one ventilation technique to another. As a general rule, the noninvasive methods are to be preferred. Tracheostomy may continue to be indicated in the event of an insufficient cultural level, recurrent aspirations, or low pulmonary compliance.

Lung volume restriction in patients with chronic respiratory muscle weakness: the role of microatelectasis.

BACKGROUND: It is well established that patients with longstanding weakness of the respiratory muscles have a reduction in lung distensibility. Although this occurs in most patients without any radiographic changes suggesting parenchymal lung disease, it has been attributed to the development of microatelectasis. METHODS: A high resolution computed tomographic (CT) scanner was used in eight patients with traumatic tetraplegia and six patients with generalised neuromuscular disorders to look for areas of atelectasis. With the patient in the supine posture scans of 1 mm thickness were obtained at total lung capacity at intervals of 1 cm from the apex to the base of the lung. RESULTS: Vital capacity, total lung capacity, and inspiratory muscle strength were reduced to a mean of 59.5%, 73.9%, and 51.1% of predicted values, respectively. Static expiratory lung compliance was decreased in 12 of the 14 patients and averaged 69.1% of the predicted value. The CT scans revealed only small areas of atelectasis in one tetraplegic patient and in one patient with a generalised neuromuscular disorder; no parenchymal abnormality was seen in the other 12 patients. CONCLUSIONS: In many patients with chronic weakness of the respiratory muscles the reduced lung distensibility does not appear to be caused by microatelectasis. It might be related to alterations in elasticity of the lung tissue.

[Surgical treatment of spinal deformities in Duchenne muscular dystrophy]. / Traitement chirurgical des déformations rachidiennes de la dystrophie musculaire de Duchenne.

Forty seven Duchenne Muscular Dystrophy patients, operated on for spinal deformity with segmental spinal instrumentation according to Luque's technique, are reviewed with a mean post-operative follow up of 4 years 4 months. The study of the results obviously showed the interest of Luque Galveston technique for the treatment of severe curves with pelvic obliquity, whereas Dove's rectangle is an interesting choice for the early instrumentation. A total spinal arthrodesis can probably be avoided in these patients, which often demonstrate a satisfying spontaneous fusion after instrumentation. The general and mechanical complications are described, according to the consequences they have on the management technique of these patients.

Precocity of pulmonary vascular obstruction of Down's syndrome.

Studying the pulmonary vascular resistance in children with ventricular septal and endocardial cushion defects, the authors found a statistically significant earlier and more severe reaction in children with Down's syndrome as compared to normals. Cardiac investigations with regard to surgical intervention should be made early in life, if the parents wish their child with Down's syndrome to undergo surgery.