Breathing Issues: Medical Literature

Recent advances in respiratory care for neuromuscular disease

Chest. 2006 Dec;130(6):1879-86.

Simonds AK.Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK.

The impact of ventilatory support on the natural history of neuromuscular disease (NMD) has become clearer over the last 2 decades as techniques have been more widely applied. Noninvasive ventilation (NIV) allows some patients with nonprogressive pathology to live to nearly normal life expectancy, extends survival by many years in patients with other conditions (eg, Duchenne muscular dystrophy), and in those patients with rapidly deteriorating disease (eg, amyotrophic lateral sclerosis) survival may be increased, but symptoms can be palliated even if mortality is not reduced. A growing number of children with NMD are surviving to adulthood with the aid of ventilatory support. The combination of NIV with cough-assist techniques decreases pulmonary morbidity and hospital admissions. Trials have confirmed that NIV works in part by enhancing chemosensitivity, and in patients with many different neuromuscular conditions the most effective time to introduce NIV is when symptomatic sleep-disordered breathing develops.

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PMID: 17167012 [PubMed – indexed for MEDLINE]

Cardiopulmonary support in duchenne muscular dystrophy

Lung. 2006 Jul-Aug;184(4):205-15.

Finsterer J.Krankenstalt Rudolfstiftung, Postfach 20, 1180 Vienna, Austria.

Duchenne muscular dystrophy (DMD) is an X-linked, rapidly progressive myopathy affecting the limb muscles, the respiratory muscles, the heart, the intestines, and the brain. Since about 90% of DMD patients die from muscular respiratory failure or cardiomyopathy, early and adequate therapy is essential. Ventilatory failure from muscle weakness requires mechanical support for ventilation and coughing as soon as there is symptomatic nocturnal hypoventilation. Today noninvasive positive-pressure ventilation (NIPPV) is the method of choice for supportive long-term mechanical ventilation in DMD. For assisted coughing, various methods are available, among which the mechanical in-exsufflator is the most widely used device. There is large nonrandomized clinical trial evidence that NIPPV improves quality of life and prolongs the lives of DMD patients if medical, social, economic, and ethical issues, raised by the availability of long-term NIPPV, are adequately addressed. Cardiac involvement in DMD manifests as impulse generation or impulse conduction abnormalities or cardiomyopathy. Cardiac abnormalities in DMD respond well to adequate therapy. Though DMD is ultimately a fatal disease, quality of life and life expectancy can be markedly improved if cardiopulmonary manifestations are adequately treated.

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PMID: 17006747 [PubMed – indexed for MEDLINE

Pulmonary manifestations of neuromuscular disease with special reference to Duchenne muscular dystrophy and spinal muscular atrophy

Comment in: Pediatr Pulmonol: 2001 Jan;31(1):89-90.
Pediatr Pulmonol. 2000 Feb;29(2):141-50.

Gozal D.Constance S. Kaufman Pediatric Pulmonary Research Laboratory, Section of Pediatric Pulmonology, Department of Pediatrics, Tulane University School of Medicine, New Orleans, Louisiana, USA.

Deterioration of respiratory function in patients with neuromuscular disorders is primarily responsible for the high mortality associated with these diseases. A review of Duchenne muscular dystrophy and spinal muscular atrophy, the leading neuromuscular disorders affecting children, will be followed by a critical analysis of the various pathophysiological mechanisms underlying respiratory manifestations in these patients. Among such mechanisms, the role of muscular weakness in preservation of lung function, mucociliary clearance, gas exchange at rest and during exercise, and respiratory control during wakefulness and sleep will be examined in detail. In addition, the potential benefits of respiratory muscle training and of early diagnosis and clinical intervention will be delineated. This review underscores the importance of periodic assessment of pulmonary function during wakefulness and sleep in children affected by neuromuscular diseases as an essential component of multidisciplinary care aimed at improving long-term morbidity, survival, and quality of life. Copyright 2000 Wiley-Liss, Inc.

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PMID: 10639205 [PubMed – indexed for MEDLINE

Respiratory muscle testing: a valuable tool for children with neuromuscular disorders

Am J Respir Crit Care Med. 2006 Jul 1;174(1):67-74. Epub 2006 Mar 30.

Nicot F, Hart N, Forin V, Boulé M, Clément A, Polkey MI, Lofaso F, Fauroux B.AP-HP, Hopital Armand Trousseau, Pediatric Pulmonary Department, Research Unit INSERM U 719, Université Pierre et Marie Curie-Paris 6, Paris, France.

RATIONALE: Data on respiratory muscle performance in children with neuromuscular disorders are limited. OBJECTIVES: The aim of this study was to assess respiratory muscle strength by volitional and nonvolitional tests and to compare these tests with forced vital capacity. METHODS: Inspiratory muscle strength was assessed by measuring transdiaphragmatic and esophageal pressures generated during volitional and nonvolitional maneuvers, whereas expiratory muscle strength was assessed by measuring the gastric pressure generated during a cough maneuver. Lung volumes were assessed by measuring forced vital capacity. MEASUREMENTS AND MAIN RESULTS: Forty-one patients with Duchenne muscular dystrophy (n = 20), spinal amyotrophy (n = 8), and congenital myopathy (n = 13) were included, aged 2 to 18 yr. All the patients were able to perform the sniff and the cough maneuver. Sniff transdiaphragmatic pressure decreased with age in Duchenne patients, whereas it increased with age in patients with spinal amyotrophy and congenital myopathy. Magnetic stimulation of the phrenic nerves was obtained in all patients. Twenty-five (61%) patients were able to perform forced vital capacity. In the three groups of patients, a positive correlation was observed between volitional, assessed by the sniff maneuver, and nonvolitional respiratory muscle tests, assessed by the magnetic stimulation of the phrenic nerves. Also, forced vital capacity correlated with sniff transdiaphragmatic pressure and cough gastric pressure. CONCLUSIONS: Volitional respiratory muscle tests correlated with nonvolitional tests and with forced vital capacity. Simple volitional respiratory muscle tests constitute a valuable tool for the assessment of respiratory muscle strength in young patients with neuromuscular disorders.

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PMID: 16574932 [PubMed – indexed for MEDLINE]

Daytime predictors of sleep disordered breathing in children and adolescents with neuromuscular disorders

Neuromuscul Disord. 2003 Feb;13(2):123-8.

Mellies U, Ragette R, Schwake C, Boehm H, Voit T, Teschler H.Department of General Pediatrics and Neuropediatrics, University of Essen, Essen,

Sleep disordered breathing with or without nocturnal hypercapnic hypoventilation is a common complication of respiratory muscle weakness in childhood neuromuscular disorders. Nocturnal hypercapnic hypoventilation as a sign of respiratory muscle fatigue, portends a particularly poor prognosis. We aimed at identifying daytime predictors of sleep disordered breathing at its onset and sleep disordered breathing with nocturnal hypercapnic hypoventilation. Forty-nine children and adolescents (11.3+/-4.4 years) with progressive neuromuscular disorders were studied with inspiratory vital capacity, peak inspiratory pressure, arterial blood gases, polysomnography, and a ten-item symptoms questionnaire. Daytime respiratory function was prospectively compared with polysomnographic variables. Sleep disordered breathing was found in 35/49 patients (71%). Twenty-four (49%) had sleep disordered breathing with nocturnal hypercapnic hypoventilation. Inspiratory vital capacity and peak inspiratory pressure, but not symptom score, correlated with sleep disordered breathing and severity of nocturnal hypercapnic hypoventilation. Sleep disordered breathing-onset was predicted by inspiratory vital capacity<60% (sens. 97%, spec. 87%). Sleep disordered breathing with nocturnal hypercapnic hypoventilation was predicted by inspiratory vital capacity<40% (sens. 96%, spec. 88%) and PaCO(2)>40 mmHg (sens. 92%, spec. 72%,). Sleep disordered breathing can reliably be predicted from simple daytime respiratory function tests, which, if applied systematically, will improve recognition of nocturnal respiratory failure.

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PMID: 12565909 [PubMed – indexed for MEDLINE]

Daytime predictors of sleep hypoventilation in Duchenne muscular dystrophy

Am J Respir Crit Care Med. 2000 Jan;161(1):166-70.

Hukins CA, Hillman DR.Department of Pulmonary Physiology, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.

Sleep hypoventilation is an inevitable consequence of Duchenne muscular dystrophy (DMD), usually preceding daytime respiratory failure. Appropriate scheduling of polysomnography and the introduction of noninvasive ventilation (NIV) during sleep are not defined. Our aim was to determine the parameters of daytime lung function associated with sleep hypoventilation in patients with DMD. As our method we chose a prospective comparison of wakeful respiratory function (spirometry, lung volumes, maximal mouth pressures, arterial blood gases) with outcomes of polysomnography. All measurements were made with subjects breathing air. Nineteen subjects were studied. The FEV(1) was correlated with Pa(CO(2)) (r = -0.70, p < 0.001) and base excess (r = -0.68, p < 0.01). All of these parameters were significantly related to sleep oxygenation (proportion of total sleep time spent at an Sa(O(2)) /= 2%); a Pa(CO(2)) of >/= 45 mm Hg was an equally sensitive (91%) but more specific (75%) indicator while a base excess of >/= 4 mmol/L was highly specific (100%) but less sensitive (55%). After introduction of NIV during sleep (n = 8), there was a significant reduction in wakeful Pa(CO(2)) (54 +/- 7.4 to 49.1 +/- 4 mm Hg, p < 0.02) over 0. 9 +/- 0.4 yr despite a further decline in FEV(1) (0.84 +/- 0.46 to 0. 64 +/- 0.39 L, p < 0.05). We conclude that in patients with DMD, (1) arterial blood gases should be performed once the FEV(1) falls below 40% of the predicted value; (2) polysomnography should be considered when the Pa(CO(2)) is >/= 45 mm Hg, particularly if the base excess is >/= 4 mmol/L; (3) the decrease in wakeful Pa(CO(2)) after NIV administered during sleep implicates sleep hypoventilation in the pathogenesis of respiratory failure; and (4) impaired ventilatory drive is a possible mechanism for respiratory failure, as the NIV-associated decrease in wakeful Pa(CO(2)) occurs despite a further decline in ventilatory capacity, suggesting continuing deterioration in respiratory muscle function.

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PMID: 10619815 [PubMed – indexed for MEDLINE]

Respiratory function assessment and intervention in neuromuscular disorders

Curr Opin Neurol. 2005 Oct;18(5):543-7.

Mellies U, Dohna-Schwake C, Voit T.University of Essen, Children’s Hospital, Department of General Pediatrics and Neuropediatrics, Essen, Germany.

PURPOSE OF REVIEW: Published research on neuromuscular respiratory failure has increased rapidly over the past decade. Progress in the management of respiratory complications and preventive care have improved outcomes and quality of life for many. In particular, noninvasive positive pressure ventilation (NIPPV) is effective in resolving respiratory failure and has dramatically changed the management of these patients. In this review we discuss recent studies assessing the course of respiratory failure, with a focus on non-Duchenne muscular dystrophy; investigating the impact NIPPV has when it is introduced before diurnal respiratory failure develops; and evaluating a device to treat insufficient cough–the mechanical insufflator–exsufflator (MI-E). RECENT FINDINGS: Studies in children with congenital muscular dystrophies and spinal muscular atrophies detected a high prevalence of respiratory complications and confirmed that respiratory failure can be predicted by measurement of vital capacity. NIPPV is an established treatment that is effective in the long-term management of end-stage diurnal respiratory failure. Additionally, recent studies showed improvement in symptoms, quality of life and prevention of respiratory complications when it is introduced for nocturnal hypoventilation before the development of diurnal respiratory failure. However, data on the efficiency of the MI-E are limited, and studies comparing it with other techniques of assisted coughing are needed. SUMMARY: Recent findings stress the importance of regular respiratory assessment in neuromuscular disease, including sleep studies; strongly support the introduction of NIPPV for management of symptomatic nocturnal hypoventilation; and suggest that prospective randomized
trials are required to verify the usefulness of the MI-E.

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PMID: 16155437 [PubMed – indexed for MEDLINE]

Randomised controlled trial of non-invasive ventilation (NIV) for nocturnal hypoventilation in neuromuscular and chest wall disease patients with daytime normocapnia

Thorax. 2005 Dec;60(12):1019-24.
Comment in: Thorax. 2005 Dec;60(12):979-80.

Ward S, Chatwin M, Heather S, Simonds AK.Clinical and Academic Department of Sleep and Breathing, Royal Brompton & Harefield NHS Trust, Sydney Street, London SW3 6NP, UK.

BACKGROUND: Long term non-invasive ventilation (NIV) reduces morbidity and mortality in patients with neuromuscular and chest wall disease with hypercapnic ventilatory failure, but preventive use has not produced benefit in normocapnic patients with Duchenne muscular dystrophy. Individuals with nocturnal hypercapnia but daytime normocapnia were randomised to a control group or nocturnal NIV to examine whether nocturnal hypoventilation is a valid indication for NIV. METHODS: Forty eight patients with congenital neuromuscular or chest wall disease aged 7-51 years and vital capacity<50% predicted underwent overnight respiratory monitoring. Twenty six with daytime normocapnia and nocturnal hypercapnia were randomised to either nocturnal NIV or to a control group without ventilatory support. NIV was started in the control group if patients fulfilled preset safety criteria. RESULTS: Peak nocturnal transcutaneous carbon dioxide tension (Tcco2) did not differ between the groups, but the mean (SD) percentage of the night during which Tcco2 was >6.5 kPa decreased in the NIV group (-57.7 (26.1)%) but not in controls (-11.75 (46.1)%; p=0.049, 95% CI -91.5 to -0.35). Mean (SD) arterial oxygen saturation increased in the NIV group (+2.97 (2.57)%) but not in controls (-1.12 (2.02)%; p=0.024, 95% CI 0.69 to 7.5). Nine of the 10 controls failed non-intervention by fulfilling criteria to initiate NIV after a mean (SD) of 8.3 (7.3) months. CONCLUSION: Patients with neuromuscular disease with nocturnal hypoventilation are likely to deteriorate with the development of daytime hypercapnia and/or progressive symptoms within 2 years and may benefit from the introduction of nocturnal NIV before daytime hypercapnia ensues.

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PMID: 16299118 [PubMed – indexed for MEDLINE]
PMCID: PMC1747266 [Available on 12/01/08]

  • Congenital Muscular Dystrophy

    A group of diseases causing muscle weakness at birth. Several defined genetic mutations cause muscles to break down faster than they can repair or grow. A child with CMD may have various neurological or physical impairments. Some children never gain the ability to walk, while others lose the ability as they grow older. Learn more...

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