During CPAPLF helmets were more efficient than FM, while during CPAPHF the three interfaces were comparable. Using CPAPVENT and PSV, FM was more efficient than helmets

A way to achieve a more even distribution of lung inflation (13-15).Hence, we designed this study of patients with early ARDS Keywords: acute lung injury; acute respiratory distress syndrome; meto test the hypothesis that prone position enhances the physichanical ventilation; recruitment; end-expiratory lung volume ologic effect of a RM. Our hypothesis is supported by the findings of a canine model of ALI showing that a lower PEEP Mechanical ventilation with low tidal volume may prevent is required in the prone than in the supine position to preserve ventilator-induced lung injury (VILI) and increased survival the effects of a RM (16). Our hypothesis is clinically relevant of patients with acute lung injury/acute respiratory distress because approximately 50% of ARDS patients do not exhibit syndrome (ALI/ARDS) (1). However, using low ventilatory a satisfactory response to a RM in the supine position (6, 7). volumes may also limit alveolar inflation and promote atelectasis and hypoxemia (2, 3). Thus, "lung protective" strategies METHODS to ventilate patients with ALI/ARDS have to consider two potentially conflicting goals: preventing VILI and reinflating Study Population collapsed alveoli. Servo ventilator 300 C (Siemens, Solna, Sweden). All had indwelling of RMs include the following: (1 ) the concomitant use of arterial and pulmonary artery catheters. The study included the following periods: baseline supine (2 hours), sighs in supine (1 hour), second baseline supine (1 hour), baseline prone (2 hours), sigh in prone (1 hour), and second baseline prone (1 hour). Measurements were taken at the end of each period, and the entire study lasted approximately 8 (Received in original form March 13, 2002; accepted in final form November 27, 2002) hours. Patients were positioned prone as previously described (14).Correspondence and requests for reprints should be addressed to Luciano GattiMechanical ventilation was provided using a tidal volume of approxinoni, Istituto di Anestesia e Rianimazione, Università degli Studi di Milano, mately 7 ml/kg of actual body weight to maintain an upper limit of This article has an online supplement, which is accessible from this issue's table because it was associated with a decreased compliance of the chest wall of contents online at www.atsjournals.org and was not deemed to reflect an increase in transpulmonary pressure.

Non-invasive positive pressure ventilation is increasingly used as a first-line treatment for respiratory failure. Non-invasive positive pressure ventilation can reduce the complications of endotracheal intubation such as barotrauma, nosocomial infections and the need for sedation. Non-invasive positive pressure ventilation has been shown to reduce the rate of endotracheal intubation in acute cardiogenic pulmonary oedema (27%), in chronic obstructive pulmonary disease (21%), and in acute respiratory failure (17%). Non-invasive positive pressure ventilation can be successfully delivered in the emergency department or in the general ward. However, the criteria for interrupting non-invasive positive pressure ventilation must be stricter (i.e. failure to improve gas exchange within 30 min) than in the general ward. One of the main reasons for the failure of non-invasive positive pressure ventilation lies in the technical problems caused by the face mask. We recently developed a new interface, the 'helmet', to deliver non-invasive positive pressure ventilation. When using the helmet instead of a face mask an increase of 10 cm H(2)O of pressure support and a fast pressurization rate are recommended. In a lung model and in healthy individuals the helmet reduced inspiratory effort. In hypoxemic patients the helmet reduced the intubation rate and the incidence of face mask-related complications. We believe that the helmet can extend the application of non-invasive positive pressure ventilation in different categories of patients with respiratory failure.

Increased intra-abdominal pressure (IAP) may occur in critically ill patients. The easiest method to estimate IAP at the bedside is the bladder pressure measurement. A standard procedure (same volume infused, pressure transducers, and patient's position) should be used to obtain comparable and reproducible data among different patients and during different stages and time of the disease. The increase in IAP leads to two major pathological conditions: 1) the intraabdominal hypertension (IAP above 16 cmH2O) and 2) the abdominal compartment syndrome (IAP above 30 cmH2O). Increased IAP negatively affects pulmonary, cardiovascular, renal, gastrointestinal and central nervous system function. Most of critically ill patients have an intraabdominal hypertension, while few of them (less than 5%) present clinical characteristics of abdominal compartment syndrome. IAP is different among different categories of patients. The highest mean values during intensive care unit stay have been reported in respiratory and cardiologic patients among medical categories and in neurologic patients among surgical patients. IAP seems to be correlated with severity scores but its relation to mortality is uncertain. Routine measurements of IAP by means of bladder pressure are not associated with an increased rate of urinary tract infections. Future trials are warranted to better evaluate the role of routine IAP measurements on clinical management of critically ill patients