Evaluation of the effects of helmet continuous positive airway pressure on laryngeal size in dogs anesthetized with propofol and fentanyl using computed tomography.

Objective: To evaluate the effect of 5 cm H O of continuous positive airway pressure (CPAP) on laryngeal size in spontaneously breathing anesthetized dogs via computed tomography (CT).

Design: Prospective, randomized, cross-over clinical study.

Setting: University teaching hospital and referral private practice.

Effects of positive end-expiratory pressure alone or an open-lung approach on recruited lung volumes and respiratory mechanics of mechanically ventilated horses.

Objective: To evaluate the effects of positive end-expiratory pressure (PEEP) alone and PEEP preceded by lung recruitment manoeuvre (LRM) on lung volumes and respiratory system mechanics in healthy horses undergoing general anaesthesia.

Study Design: Controlled, prospective clinical study.

Animals: A group of 15 horses undergoing arthroscopy.

High-flow oxygen therapy in tracheostomized patients at high risk of weaning failure.

Purpose: High-flow oxygen therapy delivered through nasal cannulae improves oxygenation and decreases work of breathing in critically ill patients. Little is known of the physiological effects of high-flow oxygen therapy applied to the tracheostomy cannula (T-HF). In this study, we compared the effects of T-HF or conventional low-flow oxygen therapy (conventional O) on neuro-ventilatory drive, work of breathing, respiratory rate (RR) and gas exchange, in a mixed population of tracheostomized patients at high risk of weaning failure.

High-flow nasal cannula oxygen therapy decreases postextubation neuroventilatory drive and work of breathing in patients with chronic obstructive pulmonary disease.

Background: The physiological effects of high-flow nasal cannula O therapy (HFNC) have been evaluated mainly in patients with hypoxemic respiratory failure. In this study, we compared the effects of HFNC and conventional low-flow O therapy on the neuroventilatory drive and work of breathing postextubation in patients with a background of chronic obstructive pulmonary disease (COPD) who had received mechanical ventilation for hypercapnic respiratory failure.

Methods: This was a single center, unblinded, cross-over study on 14 postextubation COPD patients who were recovering from an episode of acute hypercapnic respiratory failure of various etiologies.

Low respiratory rate plus minimally invasive extracorporeal Co2 removal decreases systemic and pulmonary inflammatory mediators in experimental Acute Respiratory Distress Syndrome.

Objective: The Acute Respiratory Distress Syndrome Network protocol recommends limiting tidal volume and plateau pressure; it also recommends increasing respiratory rate to prevent hypercapnia. We tested a strategy that combines the low tidal volume with lower respiratory rates and minimally invasive CO2 removal.

Subjects: Ten lung-damaged pigs (instilled hydrochloride).

Accuracy of plateau pressure and stress index to identify injurious ventilation in patients with acute respiratory distress syndrome.

Background: Guidelines suggest a plateau pressure (PPLAT) of 30 cm H(2)O or less for patients with acute respiratory distress syndrome, but ventilation may still be injurious despite adhering to this guideline. The shape of the curve plotting airway pressure versus time (STRESS INDEX) may identify injurious ventilation. The authors assessed accuracy of PPLAT and STRESS INDEX to identify morphological indexes of injurious ventilation.

Physiological effects of an open lung ventilatory strategy titrated on elastance-derived end-inspiratory transpulmonary pressure: study in a pig model*.

Rationale: In the presence of increased chest wall elastance, the airway pressure does not reflect the lung-distending (transpulmonary) pressure.

Objective: To compare the physiological effects of a conventional open lung approach titrated for an end-inspiratory airway opening plateau pressure (30 cm H2O) with a transpulmonary open lung approach titrated for a elastance-derived end-inspiratory plateau transpulmonary pressure (26 cm H2O), in a pig model of acute respiratory distress syndrome (HCl inhalation) and reversible chest wall mechanical impairment (chest wall and abdomen restriction).

Methods: In eight pigs, physiological parameters and computed tomography were recorded under three conditions: 1) conventional open lung approach, normal chest wall; 2) conventional open lung approach, stiff chest wall; and 3) transpulmonary open lung approach, stiff chest wall.

Inhomogeneity of lung parenchyma during the open lung strategy: a computed tomography scan study.

Rationale: The open lung strategy aims at reopening (recruitment) of nonaerated lung areas in patients with acute respiratory distress syndrome, avoiding tidal alveolar hyperinflation in the limited area of normally aerated tissue (baby lung).

Objectives: We tested the hypothesis that recruited lung areas do not resume elastic properties of adjacent baby lung.

Methods: Twenty-five anesthetized, mechanically ventilated pigs were studied.

ARDSnet ventilatory protocol and alveolar hyperinflation: role of positive end-expiratory pressure.

Rationale: In patients with acute respiratory distress syndrome (ARDS), a focal distribution of loss of aeration in lung computed tomography predicts low potential for alveolar recruitment and susceptibility to alveolar hyperinflation with high levels of positive end-expiratory pressure (PEEP).

Objectives: We tested the hypothesis that, in this cohort of patients, the table-based PEEP setting criteria of the National Heart, Lung, and Blood Institute's ARDS Network (ARDSnet) low tidal volume ventilatory protocol could induce tidal alveolar hyperinflation.

Methods: In 15 patients, physiologic parameters and plasma inflammatory mediators were measured during two ventilatory strategies, applied randomly: the ARDSnet and the stress index strategy.

Use of N-terminal pro-brain natriuretic peptide to detect acute cardiac dysfunction during weaning failure in difficult-to-wean patients with chronic obstructive pulmonary disease.

Objective: To evaluate the utility of serial measurements of plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) to detect acute cardiac dysfunction during weaning failure in difficult to wean patients with chronic obstructive pulmonary disease.

Design: Prospective observational cohort study.

Setting: A 14-bed general intensive care unit in a university hospital.