Cuff-leak test predicts the severity of postextubation acute laryngeal lesions: a preliminary study.

BACKGROUND AND OBJECTIVE: The objectives of the present study were to evaluate the relationships between the results of the cuff-leak test and the presence of laryngeal lesions; to assess whether lesions needing pharmacological treatment and surveillance can be predicted by the cuff-leak test; and to analyse the relationships between these lesions and postextubation stridor. METHODS: The present study is a preliminary, prospective, clinical investigation set in an 11-bed ICU of a university hospital. We studied 50 consecutive adult patients admitted to the ICU and mechanically ventilated for more than 72 h. All patients underwent cuff-leak test before extubation. A laryngoscopic inspection was performed after extubation to evaluate the presence and degrees of laryngeal lesions. Laryngeal lesions were classified according to a 5-degree scale (0-4); patients with clinical manifestations were pharmacologically treated and monitored. RESULTS: A threshold cuff-leak value of 0.07 l (21% of tidal volume) was determined by visual inspection of the receiver-operating characteristic plot. Patients were divided into a positive and a negative cuff-leak test group. Comparing the severity of laryngeal lesions to the cuff-leak test, a relationship between higher degrees of lesions (degrees 3-4) and the positivity of the cuff-leak test (31.3% in the positive cuff-leak test group vs. 3.8% in the negative cuff-leak test group; P = 0.023) was observed. The positive and the negative predictive values were 25 and 96.1%, respectively. Only two cases of postextubation stridor were found, one in each group. There was no correlation between the results of the cuff-leak test and the occurrence of postextubation acute respiratory difficulties. CONCLUSION: Cuff-leak test is a simple, noninvasive tool, which may be useful to exclude, in patients with prolonged intubations, the presence of laryngeal injuries needing medical treatment and close monitoring. This occurs independently of postextubation stridor.

Intrapulmonary percussive ventilation improves the outcome of patients with acute exacerbation of chronic obstructive pulmonary disease using a helmet.

OBJECTIVE: To evaluate the effect of intrapulmonary percussive ventilation (IPV) by mouthpiece during noninvasive positive-pressure ventilation with helmet in patients with exacerbation of chronic obstructive pulmonary disease (COPD). DESIGN: Randomized clinical trial. SETTING: General intensive care unit, university hospital. PATIENTS: Forty patients with exacerbation of COPD ventilated with noninvasive positive-pressure ventilation by helmet were randomized to two different mucus clearance strategies: IPV (IPV group) vs. respiratory physiotherapy (Phys group). As historical control group, 40 patients receiving noninvasive positive pressure and ventilated by face mask treated with respiratory physiotherapy were studied. INTERVENTIONS: Two daily sessions of IPV (IPV group) or conventional respiratory physiotherapy (Phys group). MEASUREMENTS AND MAIN RESULTS: Physiologic variables were measured at entry in the intensive care unit, before and after the first session of IPV, and at discharge from the intensive care unit. Outcome variables (need for intubation, ventilatory assistance, length of intensive care unit stay, and complications) were also measured. All physiologic variables improved after IPV. At discharge from the intensive care unit, Paco2 was lower in the IPV group compared with the Phys and control groups (mean +/- sd, 58 +/- 5.4 vs. 64 +/- 5.2 mm Hg, 67.4 +/- 4.2 mm Hg, p < .01). Pao2/Fio2 was higher in IPV (274 +/- 15) than the other groups (Phys, 218 +/- 34; control, 237 +/- 20; p < .01). In the IPV group, time of noninvasive ventilation (hrs) (median, 25th-75th percentile: 61, 60-71) and length of stay in the intensive care unit (days) (7, 6-8) were lower than other groups (Phys, 89, 82-96; control, 87, 75-91; p < .01; and Phys, 9, 8-9; control, 10, 9-11; p < .01). CONCLUSIONS: IPV treatment was feasible for all patients. Noninvasive positive-pressure ventilation by helmet associated with IPV reduces the duration of ventilatory treatment and intensive care unit stay and improves gas exchange at discharge from intensive care unit in patients with severe exacerbation of COPD.

Effects of a sigh on the respiratory mechanical properties in ali patients.

OBJECTIVES: The application of sighs during baseline ventilation was found to improve alveolar recruitment and oxygenation in patients with acute respiratory distress syndrome (ARDS). The present investigation evaluates if respiratory mechanics can be modified by a sigh. METHODS: Ten consecutive patients with acute lung injury (ALI) admitted to the University Hospital Intensive Care Unit the were studied during mechanical ventilation. Three sighs were administered to sedated-paralyzed patients during the measurement period. Respiratory mechanics were studied in regular breaths immediately before and after a sigh provided that a steady-state had been reached and by the airway pressure-time curve profile to evaluate the lung recruitment. Viscoelastic constants (elastic, resistive, and time), as well as elastance and resistances, were determined by the single breath method. Arterial blood gases were also determined pre- and post-sigh. RESULTS: Elastic and resistive components of viscoelasticity decreased after a sigh (20 and 21%, respectively). As a result, the pressure required to overcome viscoelasticity and mechanical inhomogeneities also decreased in these patients (17%). The mechanical changes were associated with alterations in PaO(2). CONCLUSIONS: The sigh is useful to diminish viscoelastic impedance in ALI patients, thus allowing a smaller inflation pressure. Under the present experimental conditions it seems that viscoelastic mechanical alterations precede their elastic and resistive counterparts.

Contributions of vascular flow and pulmonary capillary pressure to ventilator-induced lung injury.

OBJECTIVE: To evaluate the influence of vascular flow on ventilator-induced lung injury independent of vascular pressures. DESIGN: Laboratory study. SETTING: Hospital laboratory. SUBJECTS: Thirty-two New Zealand White rabbits. INTERVENTIONS: Thirty-two isolated perfused rabbit lungs were allocated into four groups: low flow/low pulmonary capillary pressure; high flow/high pulmonary capillary pressure; low flow/high pulmonary capillary pressure, and high flow/low pulmonary capillary pressure. All lungs were ventilated with peak airway pressure 30 cm H2O and positive end-expiratory pressure 5 cm H2O for 30 mins. MEASUREMENTS AND MAIN RESULTS: Outcome measures included frequency of gross structural failure (pulmonary rupture), pulmonary hemorrhage, edema formation, changes in lung compliance, pulmonary vascular resistance, and pulmonary ultrafiltration coefficient. Lungs exposed to high pulmonary vascular flow ruptured more frequently, displayed more hemorrhage, developed more edema, suffered larger decreases in compliance, and had larger increases in vascular resistance than lungs exposed to low vascular flows (p < .05 for each pairwise comparison between groups). CONCLUSIONS: These findings suggest that high pulmonary vascular flows might exacerbate ventilator-induced lung injury independent of their effects on pulmonary vascular pressures.