Long-term volume-targeted pressure-controlled ventilation: sense or nonsense?

The technology underlying the development of novel ventilatory modes for long-term noninvasive ventilation of patients with chronic hypercapnia is continuously evolving. Volume-targeted pressure-controlled ventilation is a hybrid ventilation mode designed to combine the advantages of conventional ventilation modes, while avoiding their drawbacks. However, manufacturers have created different names and have patented algorithms and set-up variables, which can result in confusion for physicians and respiratory therapists. In addition, clear evidence for the superiority of this novel mode has not yet been established. These factors have most likely hindered more widespread use of this mode in clinical practice. The current review presents the rationale, working principles, characteristics and set-up recommendations associated with volume-targeted modes. In addition, it summarises the clinical and laboratory studies that have challenged this mode.

Impact of High-Intensity-NIV on the heart in stable COPD: a randomised cross-over pilot study.

BACKGROUND: Although high-intensity non-invasive ventilation has been shown to improve outcomes in stable COPD, it may adversely affect cardiac performance. Therefore, the aims of the present pilot study were to compare cardiac and pulmonary effects of 6 weeks of low-intensity non-invasive ventilation and 6 weeks of high-intensity non-invasive ventilation in stable COPD patients. METHODS: In a randomised crossover pilot feasibility study, the change in cardiac output after 6 weeks of each NIV mode compared to baseline was assessed with echocardiography in 14 severe stable COPD patients. Furthermore, CO during NIV, gas exchange, lung function, and health-related quality of life were investigated. RESULTS: Three patients dropped out: two deteriorated on low-intensity non-invasive ventilation, and one presented with decompensated heart failure while on high-intensity non-invasive ventilation. Eleven patients were included in the analysis. In general, cardiac output and NTproBNP did not change, although individual effects were noticed, depending on the pressures applied and/or the co-existence of heart failure. High-intensity non-invasive ventilation tended to be more effective in improving gas exchange, but both modes improved lung function and the health-related quality of life. CONCLUSIONS: Long-term non-invasive ventilation with adequate pressure to improve gas exchange and health-related quality of life did not have an overall adverse effect on cardiac performance. Nevertheless, in patients with pre-existing heart failure, the application of very high inspiratory pressures might reduce cardiac output. TRIAL REGISTRATION: The trial was registered in the Deutsches Register Klinischer Studien (DRKS-ID: DRKS00007977 ).

Acidosis metabólica / Metabolic acidosis

Numerosos trastornos pueden ocasinar acidosis metabólica. El diagnóstico diferencial, apoyado en la brecha anionica, se presenta para el médico como una interesante tarea con sinuosos caminos. Su frecuencia de presentación y la potencial morbimortalidad hacen de esta revisión una atractiva fuente de información, útil para todo aquel que desee profundizar en este desorden metabólico. Se describe además las diferentes opciones teraéuticas, incluyendo drogas aun no disponibles en el mercado boliviano, así como, los fármacos que se encuentran en etapa de investigación.