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Purpose To determine if, compared to pressure support (PS), neurally adjusted ventilatory assist (NAVA) reduces patient-ventilator asynchrony in intensive care patients undergoing noninvasive ventilation with an oronasal face mask. Methods In this prospective interventional study we compared patient-ventilator synchrony between PS (with ventilator settings determined by the clinician) and NAVA (with the level set so as to obtain the same maximal airway pressure as in PS). Two 20-min recordings of airway pressure, flow and electrical activity of the diaphragm during PS and NAVA were acquired in a randomized order. Trigger delay (T.sub.d), the patient's neural inspiratory time (T.sub.in), ventilator pressurization duration (T.sub.iv), inspiratory time in excess (T.sub.iex), number of asynchrony events per minute and asynchrony index (AI) were determined. Results The study included 13 patients, six with COPD, and two with mixed pulmonary disease. T.sub.d was reduced with NAVA: median 35 ms (IQR 31-53 ms) versus 181 ms (122-208 ms); p = 0.0002. NAVA reduced both premature and delayed cyclings in the majority of patients, but not the median T.sub.iex value. The total number of asynchrony events tended to be reduced with NAVA: 1.0 events/min (0.5-3.1 events/min) versus 4.4 events/min (0.9-12.1 events/min); p = 0.08. AI was lower with NAVA: 4.9 % (2.5-10.5 %) versus 15.8 % (5.5-49.6 %); p = 0.03. During NAVA, there were no ineffective efforts, or late or premature cyclings. PaO.sub.2 and PaCO.sub.2 were not different between ventilatory modes. Conclusion Compared to PS, NAVA improved patient ventilator synchrony during noninvasive ventilation by reducing T.sub.d and AI. Moreover, with NAVA, ineffective efforts, and late and premature cyclings were absent., Author(s): Lise Piquilloud [sup.1], Didier Tassaux [sup.2], Emilie Bialais [sup.3], Bernard Lambermont [sup.4], Thierry Sottiaux [sup.5], Jean Roeseler [sup.3], Pierre-François Laterre [sup.3], Philippe Jolliet [sup.1], Jean-Pierre Revelly [sup.1] Author Affiliations: [...]

Purpose To evaluate the effects of a single daily dose of acetazolamide (ACET) on metabolic alkalosis and respiratory parameters in weaning chronic obstructive pulmonary disease (COPD) patients from invasive mechanical ventilation. Design Case-control study. Setting An 18-bed intensive care unit (ICU) in a university hospital. Patients Twenty-six intubated COPD patients with mixed metabolic alkalosis (serum bicarbonate >26 mmol/l and arterial pH [greater than or equal to]7.38) were compared with a historical control group (n = 26) matched for serum bicarbonate, arterial pH, age, and severity of illness at admission to ICU. ACET administration (500 mg intravenously) was monitored daily according to arterial blood gas analysis from readiness to wean until extubation. Results ACET was administered 4 (1-11) days throughout the weaning period. Patients with ACET treatment significantly decreased their serum bicarbonate (p = 0.01 versus baseline) and arterial blood pH (p < 0.0001), increased their PaO.sub.2/FiO.sub.2 ratio (p = 0.04), but did not change their PaCO.sub.2 (p = 0.71). Compared with matched controls, administration of ACET did not improve arterial blood gas and respiratory parameters except PaO.sub.2/FiO.sub.2 ratio (p = 0.03). ACET patients and their matched controls had similar duration of weaning. Extubation success rate was not significantly different between groups, and causes of reintubation were comparable. Conclusions ACET used at the dosage of 500 mg per day reduces metabolic alkalosis but has no benefit in terms of improving PaCO.sub.2 or respiratory parameters in weaning COPD patients from mechanical ventilation., Author(s): Christophe Faisy [sup.1], Amel Mokline [sup.1], Olivier Sanchez [sup.2], Jean-Marc Tadié [sup.1], Jean-Yves Fagon [sup.1] Author Affiliations: (1) Medical Intensive Care Unit, Hôpital Européen Georges Pompidou, Université Paris-Descartes, , [...]