The Management of Chronic Hypoventilation: Mechanical Ventilation (5)
With the wide variety of noninvasive ventilatory assist devices available, selection of a particular device depends on patient characteristics and preferences, as well as demonstrated efficacy in augmenting minute volume. In our recent experience, many patients have been opting for a trial with nasal nocturnal ventilation because of its portability and ease of application. Although further study is necessary, this approach is particularly attractive in patients with severe chest wall deformities for whom fitting of other ventilators is quite difficult. For those patients opting for “body ventilators,” periodic monitoring of oxygen saturation during sleep is advisable to rule out the occurrence of obstructive apneas, particularly in patients using negative pressure ventilators. buy ortho tri-cyclen online
For initiation of ventilator use, patients are usually hospitalized briefly for selection of optimal ventilator settings and initial adaptation to the device. We adjust ventilator settings to approximate the patients resting frequency and to augment tidal volume by 20 to 50 percent. Arterial blood gases are obtained after a two-hour daytime trial and further adjustments are made, if necessary, to lower PaC02 slightly and to maintain patient comfort. After one or two nights of nocturnal use in the hospital, patients are followed up at home by a respiratory care therapist and are given instructions to gradually extend ventilator use through the night. The goal is to have patients sleep while using the ventilator through the night with daytime PaC02 maintained between 40 and 50 mm Hg.