Nocturnal hypoventilation

Pieters T, Amy JJ, Burrini D, Aubert G, Rodenstein DO, Collard Ph. Normal pregnancy in primary alveolar hypoventilation treated with nocturnal nasal intermittent positive pressure ventilation. Eur Respir J 1995 8 1424—1427. 

Goldberg A, Leger P, Hill NS, et al. Clinical indications for noninvasive positive pressure ventilation in chronic respiratory failure due to restrictive lung disease, COPD, and nocturnal hypoventilation-a consensus conference report. Chevy Chase, MD National Association for Medical Direction of Respiratory Care, 1999 521-534. 

Figure 8 shows May s PS level on MV during her six weaning episodes, which again was erratic and lacked consistency compared with the PS level set once the long-term phase of the rehahilitation framework had been implemented (Fig. 9). Her night-time PS was increased to overcome her nocturnal hypoventilation. Her reasons for failing to wean can be seen in Table 5.

Respiratory and skeletal muscle weakness Cardiac failure Nocturnal hypoventilation Pain... 

Patients with marked symptomatic nocturnal hypoventilation... 

Ward S, Chatwin M, Heather 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 1019-1024. 

Annane D, Chevrolet JC, Chevret S, et al. Nocturnal mechanical ventilation for chronic hypoventilation in patients with neuromuscular and chest wall disorders. Cochrane Database Syst Rev 2000 (2) CD001941. 

Restrick LJ, Fox NC, Braid G, et al. Comparison of nasal pressure support ventilation with nasal intermittent positive pressure ventilation in patients with nocturnal hypoventilation. Eur... 

Careful patient selection is important if diaphragmatic pacing is to be effective. The main indications are SCI above C3, central alveolar hypoventilation, which may be idiopathic or secondary to brain stem injury, or other conditions that affect daytime or nocturnal ventilatory control. Whereas patients with high SCI require 24-hour ventilation, those with hypoventilation may only require support for part of this cycle. 

Goldstein RS, Molotiu N, Skrastins R, et al. Reversal of sleep induced hypoventilation and chronic respiratory failure by nocturnal negative pressure ventilation in patients with restrictive ventilatory impairment. Am Rev Respir Dis 1987 135 1049-1055. 

Garray SM, Turino GM, Goldring RM. Sustained reversal of chronic hypercapnia in patients with alveolar hypoventilation syndromes. Long term maintenance with non-invasive nocturnal mechanical ventilation. Am J Med 1981 70 269-274. 

Mechanical ventilation (MV) with bi-level NIV must be considered in the presence of nocturnal hypoventilation, especially if accompanied by cor pulmonale, nocturnal arryth-mias, morning headache, impaired cognitive function, or reduced daytime vigilance. Right heart failure is also frequently present. The obese sleepy patient (27) with chronic hypoxia and hypercapnia is the typical presentation of OHS. To adapt to NIV, it is important to identify the nocturnal respiratory pattern of such patients. 

Nocturnal hypoventilation, which persists during the day in obese patients with nocturnal apneas and hypoventilation may be associated with COPD, defining the overlap syndrome (3). In 264 OSAS patients (32), 30 had coexistent COPD, with hypoxemia in 57%, hypercapnia in 27%, and PH in 37% of them. In the other 234 pure OSAS patients, only 26% were hypoxic, 8.5% were hypercapnic, and 11 % had PH at baseline. The same schedule may be proposed for OHS, but long-term studies are also warranted to confirm the initial choice and continuation of nCPAP or bi-level NIV. 

Pankow W, Hijjeh I, Sehutder F, et al. Influenee of noninvasive positive pressure ventilation on inspiratory musele aetivity in obese subjects. Eur Respir J 1997 10 2847-2852. de Lucas-Ramos P, de Miguel-Diez J, Santaeruz-Siminiani A, et al. Benefits at 1 year of nocturnal intermittent positive pressure ventilation in patients with obesity-hypoventilation syndrome. Respir Med 2004 98 %l-967. 

Restoration of central chemosensitivity— by the effective control of nocturnal hypoventilation— has been shown in patients with severe obstructive sleep apnea (13), neuromuscular disease (14), and chest wall deformity as well as patients with COPD (15,16). 

In conclusion, although several theories exist, there are currently no studies on negative predictive value (NPV) or NIPPV that have provided definitive evidence that the benefits in gas exchange were related to improvements in respiratory muscle function or in sleep efficiency. The relationship between improved gas exchange and hyperinflation needs further investigation. The restoration of the central drive to breathe is the most consistent finding. It is therefore important in any evaluation of NIPPV to be confident that nocturnal hypoventilation has been reduced. 

These improvements in nocturnal alveolar hypoventilation translate into a decrease in dirrmal hypercapnia among patients with OSA and NMD (38,39). This benefit may be due to the combined effects of several interrelated processes. Reduced cerebrospinal fluid bicarbonate concentration resets the ventilatory response to CO2 and increases respiratory drive. Improved sleep quality influences the ventilatory response to CO2 and improved... 

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