Monitoring Mechanical Assisted Cough

Overview

Background Mechanical assistance cough for patients with neuromuscular disorders (NMD) are known, but there is no adaptation model established. Currently is performed subjectively by the physiotherapist following the pressures recommended in the current literature as optimal (±40CmH2O). To check is these pressures are the most optimal pressures to achieve the better peak cough flow (PCF) monitoring cough assist (Mechanical insuffllation-exsuflattion MI-E) maneuvers and analyzing pressure- flow / time curves Adults with MI-E criteria (PCFbaseline \<160 l /min). A pneumotachograph, PeakAnalysis software and nasobucal mask were used to monitor and analyze flow/time curves. Protocol included 9 PCF values in each patient: 1 baseline, 4 related with inspiratory pressure in sequential increase of 10 cmH2O (10 to 40 cmH2O) and 4 adding expiratory pressures (±10 to ±40cmH2O)

A cross-sectional observational study was performed with patients with NMD who had PFC below 160l/min according to Mechanical insufflation- exsufflation (MI-E ) criteria to assit the cough. Exclusion criteria were age \<18 years, patients who had undergone tracheostomy, exacerbated or with psychiatric problems and patients with relative contraindications (bullous emphysema background, risk of pneumothorax or recent barotrauma). MI- E study protocol An original protocol was established to perform treatment assessment with Cough Assitst T70 MI-E device® Phillips Respironics. Protocol based on 9 phases of monitoring cough. First was baseline performed for the patient without mechanical assistance and the others were performed by incremental inspiratory and expiratory pressures (cm H2O). Considering ±40 cmH2O as optimal, it was the maximum at the study. An increase of 10 cm H2O in each phase was made starting with the inspiratory pressure (10 to 40 cm H2O or maximum tolerated). Once the maximum pressure tolerated by the patient was reached, the expiratory pressure was introduced following the same sequence. (-10 to -40 cm H2O or maximum tolerated). Monitoring MI- E protocol: signals and instrumentation As a signal acquisition system, an external polygraph (16Sp Powerlab, ADInstruments, Sydney, Australia), equipped with a pressure transducer (1050 model) and a pneumotachograph (S300, instrumental dead space \_ 70 mL, resistance \_ 0.0018 cm H2O/L/s) was connected to MI-E device. Sampling frequency was set to 200 Hz, and the polygraph was connected to a personal computer equipped with Chart 7.0 software for Windows. Signal processing and analysis of waveforms, pressure-time and flow-time, were performed by this software that allowed calculate Peak cough flow maximum in each phase and checking possible respiratory events what could happen during the therapy. Parameters measured and Other assessments PCFMaximal (max) (l /min) achieved by the patient measured thorough Peak Analysis software, related to Maximal Inspiratory pressure (MIP) and Maximal Expiratory pressure (MEP) measured by cmH2O, and Phase Number like a combination of both outcomes. All phases recorded 3 respiratory cycles with cough and the best was used for the analysis. Oxygen saturation (SpO2%)and heart rate (bpm), before and after of each phase to control patient status. Patients with Amyotrophic Lateral Sclerosis (ALS) were assessed using th ALS Functional Rating Scale revised (ALSFRS-r) (cita). Bulbar impairment score was evaluated from the ALSFRS-r, from where the items of speech and swallowing were calculated.