Home mechanical ventilators

Successful assisted ventilation depends critically upon adapting mechanical ventilation to the patient s needs. This is particularly true when the noninvasive mode is used, because the patient is conscious and if ventilation is ineffective or uncomfortable, the patient may reject it. In patients with chronic respiratory failure (CRF), noninvasive ventilation (NIV) is performed during sleep and comfort is particularly important if sleep is not to be compromised. An understanding of the technical equipment, in partieular the elassiQeation and modes of ventilation and the potential problems with each, is cmcial, as is the selecticm of an appropriate interface. This chapter deals with the equipment needs for home mechanical ventilation (HMV), in particular the major ventilator types and modes, interfaces, accessories, and monitoring. 

When providing support, a ventilator can control four primary variables during inspiration pressure, volume, flow, and time. If a ventilator controls a given variable, then the waveform of this variable during inspiration will ideally remain unchanged from breath to breath regardless of how the load (compliance and resistance) changes (1). Most modem home ventilators are either pressure or flow controllers. 

Regardless of whether a ventilator uses positive pressure or negative pressure, the trans-pulmonary pressure gradient determines the tidal volume. A ventilator that is a pressure controller delivers a preset pressure and this variable is unaffected by changes in limg compliance or resistance. A positive pressure ventilator applies pressure inside the chest to expand it using a noninvasive interface, or an artificial airway. 

Negative pressure ventilators apply subatmospheric pressure outside the chest to inflate the lungs. The negative pressure causes the chest wall to expand and the pressure difference between the lungs and the atmosphere causes air to flow in. 

If flow is measured and used to deliver a preset volume, then a ventilator is considered to be a flow controller (1). In most of the cases, volume preset ventilation is provided by ventilators that actually measure flow and use flow over time to deliver a preset volume. These machines maintain an approximately constant volume in the face of varying lung mechanics. The most common flow-controlled ventilators are listed in Table 2. As indicated in the table, most of these machines can also provide pressure ventilation. 

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Abbreviations-. CRF, chronic respiratory failure HMV, home mechanical ventilation. 

Lloyd-Owen SJ, Donaldson GC, Ambrosino N, et al. Patterns of home mechanical ventilation use in Europe results from the Eurovent survey. Eur Respir J 2005 25 1025-1031. 

Cano NJ, Roth H, Court-Ortune, et al. Nutritional depletion in patients on long-term oxygen therapy and/or home mechanical ventilation. Eur Respir J 2002 20(l) 30-37. 

Make BJ. Indications for home ventilation in critical care unit patients. In Robert D, Make BJ, Leger P, et al., eds. Home Mechanical Ventilation. Paris Amette Blackwell, 1995 229-240. 

Goldstein RS. Home mechanical ventilation demographics and user perspectives. Monaldi Arch Chest Dis 1998 53(5) 560-563. 

Cazzolli PA, Oppenheimer EA. Home mechanical ventilation for amyotrophic lateral sclerosis nasal compared to tracheostomy-intermittent positive pressure ventilation. J Neurol Sci 1996 139(suppl) 123-128. 

Raphael JC, Chevret S, Chastang C, Bouvet F. Randomised trial of preventive nasal ventilation in Duchenne muscular dystrophy. French Multicentre Cooperative Group on Home Mechanical Ventilation Assistance in Duchenne de Boulogne Muscular Dystrophy. Lancet 1994 343 (8913) 1600-1604. 

Battisti A, Tassaux D, Janssens JP, et al. Performance Characteristics of 10 home mechanical ventilators in pressure-support mode a comparative bench study. Chest 2005 127 1784-1792. 

Skills related to home mechanical ventilation (HMV) technology and home care... 

Farrero E, Prats E, Povedano M, et al. Survival in amyotrophic lateral sclerosis with home mechanical ventilation the impact of systematic respiratory assessment and bulbar involvement. 

Tsara V, Serasli E, Voutsas V, et al. Burden and coping strategies in families of patients under noninvasive home mechanical ventilation. Respiration 2006 73 61-67. 

Nett LM, Obrigewith R. Home visiting system and improved quality of life. In Kira S, Petty TL, eds. Progress in Domiciliary Respiratory Care. Amsterdam Excerpta Medica, 1994. Lloyd-Owen SJ, Donaldson GC, Ambrosino N, et al. Patterns of home mechanical ventilation use in Europe results from the Eurovent survey. Eur Respir J 2005 25 1025-1031. 

Vitacca M, Guerra A, Pizzocaro P, et al. Time consuming of Physicians and Nurses before discharge in patients with chronic respiratory failure submitted to home mechanical ventilation. Rasegna di Patologia delTApparto Respiratorio 2005 20(6) 275-283. 

Gonzalex-Bermejo J, Laplanche V, Hussenini F, et al. Evaluation of the user friendliness of 11 home mechanical ventilators. Eur Respir J 2006 27(6) 1236-1243. 

Windisch W, Freidel K, Schucher B, et al. The Severe Respiratoiy Insufficiency (SRI) Questionnaire a specific measure of health-related quality of life in patients receiving home mechanical ventilation. J Clin Epidemiol 2003 56 752-759. 

Markstrom A, Sundell K, Lysdahl M, et al. Quality of life evaluation of patients with neuromuscular and skeletal diseases treated with non-invasive home mechanical ventilation. Chest... 

Duiverman M, Bladder G, Meinesz A, et al. Home Mechanical ventilation support in patients with restrictive ventilaUny disorders a 48 year experience. Respir Med 2006 100 56-65. 

Bach JR, Rajaraman R, Ballanger F, et al. Neuromuscular ventilatory insufficiency effect of home mechanical ventilator use v oxygen therapy on pneumonia and hospitalization rates. Am J Phys Med Rehabil 1998 77 8-19. 

Carlucci A, Richard JC, Wysocki M, et al. Noninvasive versus conventional mechanical ventilation. An epidemiologic survey. Am J Respir Crit Care Med 2001 163 874-880. Kacmarek RM, MaUiotra A. Equipment Required for Home Mechanical Ventilation. 2nd ed. New York McGraw-Hill, 2006. 

Servera E, Gomez-Merino E, Perez E. Home mechanical ventilation in amyotrophic lateral sclerosis patients is not always a problem. Chest 2000 117(3) 924. 

Bach J. Home mechanical ventilation for neuromuscular ventilatory failure conventional approaches and their outcomes. Bach JR, ed. Noninvasive Mechanical Ventilation. Philadelphia Hanley Belfiis, 2002 103-128. 

Muir J, Girault C, Cardinaud JP, et al. Survival and long term follow-up of tracheostomized patients with COPD treated by home mechanical ventilation. A multicenter French study in 259 patients. French Cooperative Study Group. Chest 1994 106 201-209. 

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