Journal of clinical monitoring and computing
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J Clin Monit Comput · Aug 2021
On some factors determining the pressure drop across tracheal tubes during high-frequency percussive ventilation: a flow-independent model.
To provide an in vitro estimation of the pressure drop across tracheal tubes (ΔPTT) in the face of given pulsatile frequencies and peak pressures (Pwork) delivered by a high-frequency percussive ventilator (HFPV) applied to a lung model. Tracheal tubes (TT) 6.5, 7.5 and 8.0 were connected to a test lung simulating the respiratory system resistive (R = 5, 20, 50 cmH2O/L/s) and elastic (C = 10, 20, and 50 mL/cmH2O) loads. The model was ventilated by HFPV with a pulse inspiratory peak pressure (work pressure Pwork) augmented in 5-cmH2O steps from 20 to 45 cmH2O, yielding 6 diverse airflows. ⋯ RMSE of the model on the testing dataset was 1.17 cmH2O, r2 was 0.79 and estimation error was lower than 1 cmH2O in 68% of cases. As a result, even without a flow value, the physician would be able to evaluate ΔPTT pressure. If the present results of our bench study could be clinically confirmed, the use of a nonconventional ventilatory strategy as HFPV, would be safer and easier.
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J Clin Monit Comput · Aug 2021
Predicting unconsciousness after propofol administration: qCON, BIS, and ALPHA band frequency power.
During anesthesia induction with propofol the level of arousal progressively decreases until reaching loss of consciousness (LOC). In addition, there is a shift of alpha activity from parieto-occipital to frontal zones, defined as anteriorization. Whilst monitoring LOC and anteriorization would be useful to improve propofol dosage and patient safety, the current devices for anesthetic depth monitoring are unable to detect these events. ⋯ Pk values for BIS and qCON were strongly predictive of frontal alpha absolute power. During anesthesia induction with propofol it is possible to identify anteriorization with BIS and qCON in the frontal and parieto-occipital regions. Both indices showed different patterns which need to be further studied.
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J Clin Monit Comput · Aug 2021
A new reliable acoustic respiratory monitoring technology during upper gastrointestinal tract therapeutic endoscopy with CO2 insufflation.
Previous studies documented the effectiveness and benefits of capnography monitoring during propofol-based sedation for colonoscopy to reduce the incidence of hypoxemia. However, the performance of capnography during longer duration endoscopic therapy of upper gastrointestinal tract cancers under CO2 insufflation it is not well known. In this study, we compare a new device with acoustic monitoring technology to standard capnography monitoring. ⋯ The ratio of unmeasurable respiratory rate by capnography was strongly correlated to the ratio of unmeasurable PETCO2 level by capnography (R2 = 0.847). There were no severe events or adverse events (grade 2 or more) during all 49 procedures. The acoustic monitoring technology provides a more reliable respiratory monitoring when compared to standard capnography during endoscopic resection of upper gastrointestinal tract cancers under CO2 insufflation, even if the procedures were prolonged and complex.
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J Clin Monit Comput · Aug 2021
Non-invasive assessment of respiratory muscle activity during pressure support ventilation: accuracy of end-inspiration occlusion and least square fitting methods.
Pressure support ventilation (PSV) should be titrated considering the pressure developed by the respiratory muscles (Pmusc) to prevent under- and over-assistance. The esophageal pressure (Pes) is the clinical gold standard for Pmusc assessment, but its use is limited by alleged invasiveness and complexity. The least square fitting method and the end-inspiratory occlusion method have been proposed as non-invasive alternatives for Pmusc assessment. ⋯ Both Pmusc,lsf ≤ 4 cmH2O and Pmusc,index ≤ 1 cmH2O had excellent negative predictive value [0.98 (95% CI 0.94-1) and 0.96 (95% CI 0.91-0.99), respectively)] to identify over-assistance. The inspiratory effort during PSV could not be accurately estimated by the least square fitting or end-inspiratory occlusion method because the limits of agreement were far above the signal size. These non-invasive approaches, however, could be used to screen patients at risk for absent or minimal respiratory muscles activation to prevent the ventilator-induced diaphragmatic dysfunction.