Résumé :
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Both volume- and pressure targeted long term non-invasive ventilation have been shown to be effective in patients with kyphoscoliosis with regard to an improved gas exchange. Aim : As it is unknown which kind of treatment is the most easy to implement, both types of ventilatory support were compared in patients with respiratory failure due to kyphoscoliosis who had not been ventilated before. Methods : Our primary outcome measure was number of days needed to achieve effective ventilation. Thirteen patients were included (5 post polio, 6 with early onset kyphoscoliosis, 1 thoracoplasty after tuberculosis and 1 kyphoscoliosis after rachitis). Mean age was 66 years, while their mean VC was 1,2 L. Seven patients were randomised to volume ventilation and 6 were randomised to receive pressure targeted ventilation. The effectiveness of ventilation was monitered by arterial blood gas registration during the night before initiation (T0), after patients could sleep with ventilation for at least 6 hours per night before they were discharged from hospital (T1), and after 3 months of ventilation during the night at home (T2). Results : Two patients switched from volume ventilation to pressure ventilation after 2 days due to lack of tolerance, resulting in 8 patients in the pressure targeted group and 5 in the volume targeted group.We found an effective ventilation in the volume group after a mean of 6,0 days and in the pressure group after a mean of 7,6 days, which was not significantly different (p = 0,299). Both treatments showed improvements in PaCO2 between the initiation of ventilation and day of discharge with a decrease in the volume group from a mean PaCO2 of 7,13 to 6,05 kPa (p = 0,068) and a decrease in the pressure group from 7,6 to 5,30 kPa (p = 0,025). These drops were maintained and significant in both groups after 3 months, but were not significantly different between both treatments. We also found improvements in PaO2 at discharge and 3 months as compared with baseline, but these were only significant in the volume targeted ventilation group (p = 0,043) with no significant differences in effectiveness between both treatments. Conclusions and discussion : We conclude that that there is no difference in days needed to achieve effective ventilation in either volume- or pressure targeted ventilation. Noteworthy is the fact that 2 patients switched from volume ventilation to pressure ventilation suggesting that the latter is preferred by the patient.
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