Optimization of Ventilator Setting for Acute Exacerbations of Chronic Obstructive Pulmonary Disease (NIMV01AECB)

Optimization of Ventilator Setting by Flow and Pressure Curves Analysis During Noninvasive Ventilation for Acute Exacerbations of Chronic Obstructive Pulmonary Disease

Ospedale Campo di Marte, UO Pneumologia e UTSIR, Lucca, IT, Valduce Hospital, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Ente Ospedaliero Cantonale, Bellinzona, Azienda Ospedaliera San Gerardo di Monza

The analysis of flow and pressure curves generated by ventilators can be useful in the individuation of patient-ventilator asynchrony, notably in COPD patients. To date, however, a real clinical benefit of this approach to optimize ventilator setting has not been proven. The aim of the present study was to compare: optimized ventilation, driven by the analysis of flow and pressure curves, and standard setting (same initial setting, same time at the bedside, same physician, while the ventilator screen was obscured with numerical data always available). The primary aim was the normalization of pH at two hours, whilst secondary aims were change in PaCO2, respiratory rate, patient's tolerance to ventilation (all parameter evaluated at baseline, 30, 120, 360 minutes and 24 hours after the beginning of ventilation). 70 patients (26 females, aged 78±9 years, PaCO2 74±15 mmHg, pH 7.28±0.05, mean±SD) have been enrolled, with no basal difference between the two groups.

Patients, ventilated in pressure support mode, were ventilated with initial setting PEEP and pressure support of 4 and as maximum tolerated cmH2O, inspiratory and expiratory trigger of 5 L/min and 50% of peak inspiratory flow, with changes driven by the analysis of flow and pressure curves; with a FiO2 to reach a SpO2 level between 88 and 92%.

Patients, ventilated in pressure support mode, were ventilated with standard setting of ventilation: -same initial setting, same time at the bedside (15 minutes at the beginning of NIV, and 5 minutes at each patients' new evaluation) same physician that "optimized ventilation" mode, while the ventilator screen was obscured (numerical data were, however, always available).

The primary outcome was the normalization of arterial pH (=pH≥7.35) at 2 hours from the beginning of non invasive ventilation

carbon dioxide tension (mmHg) in arterial blood measured 12O, 360 minutes and 24 hours after beginning of non invasive ventilation

respiratory rate (RR) measured 120, 360 minutes and 24 hours after the beginning of non invasive ventilation

The patients tolerance to ventilation was evaluated on a visual analogue scale. This scale has been used and validated in previous studies and has five scores: 1) bad; 2) poor; 3) sufficient; 4) good; and 5) very good.

Inclusion Criteria: Consecutive patients aged > 40 years affected by COPD exacerbation (defined as an acute change in a patient's baseline dyspnoea, cough and/or sputum beyond day-to-day variability sufficient to warrant a change in therapy), and respiratory acidosis (pH < 7.35) that were treated by NIV in addition to standard medical therapy Exclusion Criteria: The needing of intubation The lack of informed consent

Policlinico S.Orsola Malpighi, Università di Bologna, Pneumologia e Terapia Intensiva Respiratoria Bologna, BO, Italy

Respiratory Medicine Section, Dipartimento Toraco-Polmonare e Cardiocircolatorio, Università degli Studi di Milano, San Paolo Hospital

Respiratory Medicine Section, Dipartimento Toraco-Polmonare e Cardiocircolatorio, Università degli Studi di Milano, San Paolo Hospital

Di Marco F, Centanni S, Bellone A, Messinesi G, Pesci A, Scala R, Perren A, Nava S. Optimization of ventilator setting by flow and pressure waveforms analysis during noninvasive ventilation for acute exacerbations of COPD: a multicentric randomized controlled trial. Crit Care. 2011;15(6):R283. doi: 10.1186/cc10567. Epub 2011 Nov 24.