Hypercapnic respiratory failure

Neuromuscular function Respiratory muscle paralysis leading to hypercapnic respiratory failure requiring mechanical ventilation has been attributed to intravenous and inhaled colistimethate sodium [103 ]. 

Hypercapnic respiratory failure is due to failure of the ventilatory pump caused by acute (drug overdose, acute neuromuscular diseases) or chronic (chest wall abnormalities, chronic neuromuscular diseases) disorders. It is characterized by alveolar hypoventilation, which leads to hypercapnia with coexistent, usually mild, hypoxemia. The central drive may be globally reduced with the fall in Pa02 resulting from the increase in alveolar CO2. More commonly, the drive remains high, but the mechanical load on the respiratory systan is too great or the capacity of the muscles too low to ensure efficient CO2 elimination (Fig. 1). 

For a given level of CO2 production (VCO2), hypercapnic respiratory failure results only from an inadequate VA. A simple equation describes these relationships quantitatively under steady state conditions ... 

From these equations, it follows that VA decreases and so Pacx>2 increases when VE decreases. Likewise, when VE and VD remain unchanged but VT decreases and respiratory frequency (RF) increases (rapid shallow breathing), Pacx)2 increases. Patients adopt a rapid shallow breathing pattern to minimize respiratory work per breath, but this form of compensatory behavior can be deleterious to gas exchange and is a major factor producing chronic hypercapnic respiratory failure in patients with COPD and neuromuscular disorders (6-10). 

The function of the ventilatory pump is critically dependent on three factors the respiratory workload, the respiratory muscle strength, and the ventilatory drive (Fig. 1). Chronic hypercapnic respiratory failure can result from one or more of these abnormalities inadequate ventilatory drive, excessive respiratory load, and inadequate inspiratory muscle... 

Elliott MW, Simonds AK, Carroll MP, et al. Domiciliary nocturnal nasal intermittent positive pressure ventilation in hypercapnic respiratory failure due to chronic obstructive lung disease effects on sleep and quality of life. Thorax 1992 47(5) 342-348. 

Sivasothy P, Smith IE, Shneerson JM. Mask intermittent positive pressure ventilation in chronic hypercapnic respiratory failure due to chronic obstructive pulmonary disease. Eur Respir J 1998 ll(l) 34-40. 

Piper AJ, Parker S, Torzillo PJ, et al. Nocturnal nasal IPPV stabilizes patients with cystic fibrosis and hypercapnic respiratory failure. Chest 1992 102 846-850. 

Navalesi P, Fanfulla F, Frigerio P, et al. Physiologic evaluation of noninvasive mechanical ventilation delivered with three types of masks in patients with chronic hypercapnic respiratory failure. Crit Care Med 2000 28 1785-1790. 

Schols AM, Slangen J, Volovics L, et al. Weight loss is a reversible factor in the prognosis of chronic obstructive pulmonary disease. Am J Respir Crit Care Med 1998 157 1791-1797. Sivasothy P, Smith IE, Shneerson JM. Mask intermittent positive pressure ventilation in chronic hypercapnic respiratory failure due to chronic obstructive pulmonary disease. Eur Respir J 1998 11 34-40. 

OHS, previously called the Pickwickian syndrome (6), is defined as the association of obesity, sleep-disordered breathing (SDB) with daytime h)q)ersomnolence, and hypercapnia (Pacc>2 > 45 mmHg) in the absence of any other respiratory disease (Fig. 1). SDB can present as obstructive apneas and hypopneas, obstructive hypoventilation due to increased upper airway resistance, and/or central hypoventilation (7). The prevalence of OHS is 36% in patients with BMI between 35 and 40 kg/m, and 48%, if BMI equals or exceeds 50 (8). Without adequate treatment, patients with OHS develop cor pulmonale and recurrent episodes of hypercapnic respiratory failure, and loss of survival (Fig. 2). OHS is one of the many etiologies of CRF and has become a growing indication to initiate longterm noninvasive ventilation (NIV) in most European countries (9,10). 

Tirlapur VG, Mir MA. Effect of low calorie intake on abnormal pulmonary physiology in patients with chronic hypercapnic respiratory failure. Am J Med 1984 77 987-994. 

Shivaram U, Cash ME, Beal A. Nasal continuous positive airway pressure in decompensated hypercapnic respiratory failure as a complication of sleep apnea. Chest 1993 104 770-774. Sturani C, Galavotti Y, Scarduelli C, et al. Acute respiratory failure due to severe obstructive sleep apnea syndrome, managed with nasal positive pressure ventilation. Monaldi Arch Chest Dis 1994 49 558-560. 

Chronic health care in Europe, like the rest of the developed world, is characterized by an increasingly aging population often with complex medical problems, an increase in societal expectations, and an increase in the dependence on expensive technology. Chronic respiratory failure is no different and is expected to rise in prevalence because of the aging population and possibly because of increased tobacco use. The expansion in Europe (1-3) and the United States (4) over the last three decades in the use of home mechanical ventilation (HMV) mirrors this trend. HMV is used to treat chronic hypercapnic respiratory failure in both adults and children and is usually delivered non-invasively (NIV) with the majority of patients using only nocturnal or nocturnal plus part daytime NIV. NIV has been shown to reduce mortality and morbidity (5,6) and to improve quality of life (7). 

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