Novelties in COPD prognosis: evolution of survival indexes.

Despite several techniques, such as non-invasive ventilation (NIV), have improved the outcome of the acute exacerbation, COPD remains affected by poor prognosis in the medium and long term. Moreover, the task of predicting prognosis remains a major challenge for respiratory physicians. In order to overcome this limitation, several indexes have been proposed to assess the COPD patient in his/her complexity. The rationale is that, by using numerical indexes physicians may improve their clinical judgment to tailor and share therapeutical choices, i.e. referring the patient for surgery or lung transplantation. On this ground, Almagro et al. recently proposed the CODEX index, as the latest evolution of the BODE through the BODEx (which takes into account exacerbations), by adding the evaluation of comorbidity to the severity of dyspnoea, airway obstruction and history of exacerbations. As afore mentioned, treatment of COPD with respiratory acidosis has been revolutionized by the use of NIV, by reducing the need for intubation and in-hospital mortality of patients with severe COPD exacerbations. Nowadays, new promising techniques, such as minimally invasive extracorporeal devices, may hasten the clearance of carbon dioxide and reduce the work of breathing and the need for ventilation of COPD patients. These techniques still lack of randomized controlled studies; however, the approach of extracorporeal CO2 removal has the potential to further improve the prognosis of severe exacerbation of COPD patients. In this paper we discuss the prognostic evaluation of patients affected by COPD through the evolution of dedicated indexes, which mirror the focus of current research on the disease.

Are benzodiazepines and opioids really safe in patients with severe COPD?

Breathlessness is a key symptom in chronic obstructive pulmonary disease (COPD) with prognostic implications on health status and survival. Since most conditions underlying chronic refractory breathlessness in COPD are not modifiable, the use of opioids and benzodiazepines has been proposed to relieve it. However, respiratory depression is a known adverse event of these drugs, and concerns have been raised on their use in patients with chronic respiratory failure. Despite safety-related concerns, benzodiazepines are frequently prescribed for a variety of reasons, including treatment of insomnia, depression and anxiety, as well as to relieve refractory dyspnea in patients with COPD. The key role of opioids in the end-of-life and in the management of dyspnea that is unresponsive to best-possible disease management is recognized. Moreover, the use of low dose opioids to treat dyspnea, discomfort or refusal for patient undergoing non-invasive ventilation is still debated. In the current review, we aim at discussing and analyzing recently published findings on the use of benzodiazepines and opioids in patients with COPD and at reviewing the literature on this topic. Recent observations favor the use of lower doses of opioids (≤30 mg oral morphine equivalents/day) for reduction of symptoms in those patients with severe COPD receiving long-term oxygen therapy. Low dose opioids are not associated with an increased risk of hospital admission or death in cohorts of COPD patients on long term oxygen therapy. On the contrary, benzodiazepines and opioids at higher doses might increase mortality.

Potentially harmful effects of inspiratory synchronization during pressure preset ventilation.

PURPOSE: Pressure preset ventilation (PPV) modes with set inspiratory time can be classified according to their ability to synchronize pressure delivery with patient's inspiratory efforts (i-synchronization). Non-i-synchronized (like airway pressure release ventilation, APRV), partially i-synchronized (like biphasic airway pressure), and fully i-synchronized modes (like assist-pressure control) can be distinguished. Under identical ventilatory settings across PPV modes, the degree of i-synchronization may affect tidal volume (VT), transpulmonary pressure (PTP), and their variability. We performed bench and clinical studies. METHODS: In the bench study, all the PPV modes of five ventilators were tested with an active lung simulator. Spontaneous efforts of -10 cmH2O at rates of 20 and 30 breaths/min were simulated. Ventilator settings were high pressure 30 cmH2O, positive end-expiratory pressure (PEEP) 15 cmH2O, frequency 15 breaths/min, and inspiratory to expiratory ratios (I:E) 1:3 and 3:1. In the clinical studies, data from eight intubated patients suffering from acute respiratory distress syndrome (ARDS) and ventilated with APRV were compared to the bench tests. In four additional ARDS patients, each of the PPV modes was compared. RESULTS: As the degree of i-synchronization among the different PPV modes increased, mean VT and PTP swings markedly increased while breathing variability decreased. This was consistent with clinical comparison in four ARDS patients. Observational results in eight ARDS patients show low VT and a high variability with APRV. CONCLUSION: Despite identical ventilator settings, the different PPV modes lead to substantial differences in VT, PTP, and breathing variability in the presence spontaneous efforts. Clinicians should be aware of the possible harmful effects of i-synchronization especially when high VT is undesirable.

Recent advances in interfaces for non-invasive ventilation: from bench studies to practical issues.

The interface is the defining element of non-invasive ventilation (NIV). Nowadays different types of interfaces, which differ in terms of shape, mechanical properties and comfort, are available, and their choice and fitting is a key element of NIV success. In the last decade, larger masks covering the entire face and specifically designed helmets have been developed for delivering NIV, theoretically improving comfort and patient tolerance. Recent studies have shown that, despite marked heterogeneity in mask internal volume and compliance, the dynamic dead space and, above all, the clinical efficacy of different masks is on average very similar. Thus, with the exception of the nasal mask and the mouthpiece, a variety of interfaces for NIV can be used in the acute care setting. However, prevention and monitoring of interfaces related side-effects and evaluation of patient tolerance are crucial to avoid NIV failure. To optimize effectiveness and costs, an interface strategy for NIV in acute respiratory failure could be convenient in clinical practice.