Noninvasive mechanical ventilation with high pressure strategy remains a “double edged sword”?

Correspondence: Antonio M Esquinas Intensive Care Unit, Hospital Morales Meseguer, Avenida Marques Velez s/n, Murcia, 30008, Spain Email [email protected] Dear editor We read with great interest the original work by Murphy et al analyzing the effects of two treatment strategies for delivery of noninvasive mechanical ventilation in hypercapnic patients with chronic obstructive pulmonary disease. High pressure and high intensity noninvasive mechanical ventilation were compared in a short-term crossover trial to assess whether high intensity noninvasive mechanical ventilation (inspiratory pressure  25 cm H 2 O associated with a high backup ventilator rate) may improve adherence, physiological, and subjective outcomes when compared with delivery of high pressure noninvasive mechanical ventilation (without elevated backup respiratory rate). The authors concluded that both strategies are equivalent in all the recorded outcomes, showing thus that driving pressure, but not backup respiratory rate, is essential to gain physiological and clinical benefits in this population when in a chronic stable condition. Despite previous randomized studies showing the potential benefits of long-term noninvasive mechanical ventilation in hypercapnic patients with chronic obstructive pulmonary disease, current research has still not clearly indicated the best strategy to improve the patient’s adherence with treatment. Overall, dropout during noninvasive mechanical ventilation remains a serious clinical problem. This study provides valuable information in this regard, suggesting that sufficiently high-pressure delivery is enough to achieve useful clinical and physiological goals. This notwithstanding, we believe that some of the expectations following the adoption of these different noninvasive mechanical ventilation strategies have not been adequately addressed in the present study. Therefore, we consider that it would be useful, from a practical point of view, to underline some points in this regard. First, the authors did not determine what effects the highest respiratory backup rate used in their study may have had. Although there have been no major studies published on application of high levels of backup that have proved to be useful in patients with severe chronic obstructive pulmonary disease, this is the best indication for hypoventilation syndromes, ie, obesity and overlap syndromes. In fact, we cannot exclude that addition of a high backup respiratory rate may help to resolve “overlap” when present at a subclinical level in patients with chronic obstructive pulmonary disease, or that it has not been adequately assessed before. However, it seems that the authors selected backup respiratory rate levels on a clinical basis without any physiological assessment in their study population. Despite patients in the present Dovepress