Performance of helmet CPAP using different configurations: Turbine-driven ventilators Venturi devices.

Background: Traditionally, Venturi-based flow generators have been preferred over mechanical ventilators to provide continuous positive airway pressure (CPAP) through the helmet (h-CPAP). Recently, modern turbine-driven ventilators (TDVs) showed to be safe and effective in delivering h-CPAP. We aimed to compare the pressure stability during h-CPAP delivered by Venturi devices and TDVs and assess the impact of High Efficiency Particulate Air (HEPA) filters on their performance.

Performance of EasyBreath Decathlon Snorkeling mask for delivering continuous positive airway pressure.

During the COVID-19 pandemic, the need for noninvasive respiratory support devices has dramatically increased, sometimes exceeding hospital capacity. The full-face Decathlon snorkeling mask, EasyBreath (EB mask), has been adapted to deliver continuous positive airway pressure (CPAP) as an emergency respiratory interface. We aimed to assess the performance of this modified EB mask and to test its use during different gas mixture supplies.

Comparing airways clearance techniques in chronic obstructive pulmonary disease and bronchiectasis: positive expiratory pressure or temporary positive expiratory pressure? A retrospective study.

Background: Airway clearance techniques include positive expiratory pressure, commonly used in our clinical practice, and a recently introduced temporary positive expiratory pressure device called UNIKO. It is unclear which one provides the best benefit to patients.

Objectives: The aim of this observational 4-year study was to retrospectively compare the efficacy of and specific indications for temporary positive expiratory pressure compared to positive expiratory pressure in a standard rehabilitation program.

Endothelin inhibitors lower pulmonary vascular resistance and improve functional capacity in patients with Fontan circulation.

Objectives: To evaluate the effects of endothelin inhibitors (ERAs) on hemodynamic and functional parameters in patients post-Fontan procedure with high pulmonary vascular resistance (PVR).

Methods: Among our cohort of patients with Fontan circulation, 8 children, 8 adolescents, and 8 adults had PVR ≥2 WU*m. These patients were treated with ERAs (minors with bosentan, adults with macitentan) and reevaluated after 6 months.

Noninvasive method for measuring respiratory system compliance during pressure support ventilation.

Purpose: To date, few methods have been accepted for assessing the respiratory system compliance (C(rs)) in patients under assisted ventilation at the bedside. The aim of this study was to evaluate our adaptive time slice method (ATSM) to continuously calculate the C(rs).

Methods: One breath is divided into several time periods (slices).

High-resolution computed tomography quantitation of emphysema is correlated with selected lung function values in stable COPD.

Background: The literature shows conflicting results when high-resolution computed tomography (HRCT) scores of emphysema were correlated with different indices of airflow obstruction.

Objectives: We correlated HRCT scores of emphysema with different indices of airflow obstruction.

Methods: We performed HRCT of the chest in 59 patients, all smokers or ex-smokers, with stable chronic obstructive pulmonary disease of different severity [GOLD stages I-IV; mean age ± SD 67.

Mechanisms of gas exchange response to lung volume reduction surgery in severe emphysema.

Lung volume reduction surgery (LVRS) improves lung function, respiratory symptoms, and exercise tolerance in selected patients with chronic obstructive pulmonary disease, who have heterogeneous emphysema. However, the reported effects of LVRS on gas exchange are variable, even when lung function is improved. To clarify how LVRS affects gas exchange in chronic obstructive pulmonary disease, 23 patients were studied before LVRS, 14 of whom were again studied afterwards.

On-line monitoring of lung mechanics during spontaneous breathing: a physiological study.

Background: Monitoring the mechanics of breathing in patients with advanced chronic obstructive lung diseases prior to lung transplantation is useful to characterize changes in the mechanical properties of the lungs. On-line methods of monitoring immediately process the data for clinical decisions. However, the few available methods are so far limited to monitor respiratory mechanics in ventilator-dependent patients.

Helmet ventilation for acute respiratory failure and nasal skin breakdown in neuromuscular disorders.

Noninvasive ventilation (NIV) has been widely used to decrease the complications associated with tracheal intubation in mechanically ventilated patients with neuromuscular diseases in acute respiratory failure. However, nasal ulcerations might occur when masks are used as an interface. Helmet ventilation is a possible option in this case.

Mechanical determinants of early acute ventilatory failure in COPD patients: a physiologic study.

Objective: The purpose of this study is to investigate the respiratory mechanics, breathing pattern, and pressure-generating capacity of respiratory muscles during the early phases of an acute exacerbation of COPD.

Design: Prospective study.

Setting: Division of Emergency Critical Care and Chronic Ventilator Unit.

Helmet ventilation and carbon dioxide rebreathing: effects of adding a leak at the helmet ports.

Objective: We examined whether additional helmet flow obtained by a single-circuit and a modified plateau valve applied at the helmet expiratory port (open-circuit ventilators) improves CO(2) wash-out by increasing helmet airflow.

Design And Setting: Randomized physiological study in a university research laboratory.

Participants: Ten healthy volunteers.

Patient-ventilator interaction and sleep in mechanically ventilated patients: pressure support versus proportional assist ventilation.

Objectives: To understand the role of patient-ventilator asynchrony in the etiology of sleep disruption and determine whether optimizing patient-ventilator interactions by using proportional assist ventilation improves sleep.

Design: Randomized crossover clinical trial.

Setting: A tertiary university medical-surgical intensive care unit.

Noninvasive proportional assist ventilation and pressure support ventilation during arm elevation in patients with chronic respiratory failure. A preliminary, physiologic study.

Background: It has been shown that upper limbs activity increases the respiratory workload in patients with chronic respiratory failure (CRF). The object of the present study was to investigate whether, in these patients: (i) noninvasive positive pressure ventilation (NPPV) could sustain the inspiratory muscles to meet the greater ventilatory demand during upper limbs activity with the arm elevation test (AE); (ii) proportional assist ventilation (PAV) might be superior to pressure support ventilation (PSV) during AE, because of its potential more adaptable response to sudden changes in the ventilatory pattern.

Methods: The study was performed in the pulmonary function laboratory of the Pulmonary Division in Verona General Hospital, Verona, Italy.

Effectiveness of mask and helmet interfaces to deliver noninvasive ventilation in a human model of resistive breathing.

The helmet, a transparent latex-free polyvinyl chloride cylinder linked by a metallic ring to a soft collar that seals the helmet around the neck, has been recently proposed as an effective alternative to conventional face mask to deliver pressure support ventilation (PSV) during noninvasive ventilation in patients with acute respiratory failure. We tested the hypothesis that mechanical characteristics of the helmet (large internal volume and high compliance) might impair patient-ventilator interactions compared with standard face mask. Breathing pattern, CO(2) clearance, indexes of inspiratory muscle effort and patient-ventilator asynchrony, and dyspnea were measured at different levels of PSV delivered by face mask and helmet in six healthy volunteers before (load-off) and after (load-on) application of a linear resistor.

Mask proportional assist vs pressure support ventilation in patients in clinically stable condition with chronic ventilatory failure.

Objective: To compare the short-term physiologic effects of mask pressure support ventilation (PSV) and proportional assist ventilation (PAV) in patients in clinically stable condition with chronic ventilatory failure (CVF).

Design: Randomized, controlled physiologic study.

Setting: Lung function units of two pulmonary rehabilitation centers.

Diaphragm fatigue during exercise at high altitude: the role of hypoxia and workload.

The effect of high altitude (HA) on exercise-induced diaphragm fatigue in normal subjects was examined. Eight normal subjects completed an incremental exercise test at sea level (SL) and at 3,325 m. Before (baseline), during, and after exercise (recovery), maximal transdiaphragm pressure (Pdi,sniff), breathing pattern, and diaphragmatic effort (PTPdi) were measured.

Clinical relevance of monitoring respiratory mechanics in the ventilator-supported patient: an update (1995-2000).

The introduction of mechanical ventilation in the intensive care unit environment had the merit of putting a potent life-saving tool in the physicians' hands in a number of situations; however, like most sophisticated technologies, it can cause severe side effects and eventually increase mortality if improperly applied. Assessment of respiratory mechanics serves as an aid in understanding the patient-ventilator interactions with the aim to obtain a better performance of the existing ventilator modalities. It has also provided a better understanding of patients' pathophysiology.

Physiologic determinants of ventilator dependence in long-term mechanically ventilated patients.

To investigate the pathophysiologic mechanisms of ventilator dependence, we took physiologic measurements in 28 patients with COPD and 11 postcardiac surgery (PCS) patients receiving long-term mechanical ventilation during a spontaneous breathing trial, and in 20 stable, spontaneously breathing patients matched for age and disease. After 40 +/- 14 min of spontaneous breathing, 20 of 28 patients with COPD and all 11 PCS patients were judged ventilator-dependent (VD). We found that in the 31 VD patients tidal volume was low (VT: 0.

Physiologic response of ventilator-dependent patients with chronic obstructive pulmonary disease to proportional assist ventilation and continuous positive airway pressure.

To investigate the physiologic effects of proportional assist ventilation (PAV) in difficult-to-wean, mechanically ventilated patients with advanced COPD, we measured in eight ICU patients the breathing pattern, neuromuscular drive (P0.1), lung mechanics, and inspiratory muscle effort (PTPdi and PTPpl) during both spontaneous breathing (SB) and ventilatory support with PAV, CPAP, and CPAP + PAV (in random sequence). PAV (volume assist [VA] and flow assist [FA]) was set as follows: dynamic lung elastance and inspiratory pulmonary resistance were measured during SB; then VA and FA were set to counterbalance the elastic and resistive loads exceeding the normal values, respectively, the inspiratory muscles bearing a normal elastic and resistive workload.