scholarly journals Flow Index accurately identifies breaths with low or high inspiratory effort during pressure support ventilation

Critical Care ◽  
2021 ◽  
Vol 25 (1) ◽  
Author(s):  
Filippo Albani ◽  
Federica Fusina ◽  
Gianni Ciabatti ◽  
Luigi Pisani ◽  
Valeria Lippolis ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Respiratory Rate ◽  
Pressure Support Ventilation ◽  
Pressure Support ◽  
Inspiratory Effort ◽  
Flow Index ◽  
Support Ventilation ◽  
Airway Occlusion ◽  
Inspiratory Muscles ◽  
Time Waveform

Abstract Background Flow Index, a numerical expression of the shape of the inspiratory flow-time waveform recorded during pressure support ventilation, is associated with patient inspiratory effort. The aim of this study was to assess the accuracy of Flow Index in detecting high or low inspiratory effort during pressure support ventilation and to establish cutoff values for the Flow index to identify these conditions. The secondary aim was to compare the performance of Flow index,of breathing pattern parameters and of airway occlusion pressure (P0.1) in detecting high or low inspiratory effort during pressure support ventilation. Methods Data from 24 subjects was included in the analysis, accounting for a total of 702 breaths. Breaths with high inspiratory effort were defined by a pressure developed by inspiratory muscles (Pmusc) greater than 10 cmH2O while breaths with low inspiratory effort were defined by a Pmusc lower than 5 cmH2O. The areas under the receiver operating characteristic curves of Flow Index and respiratory rate, tidal volume,respiratory rate over tidal volume and P0.1 were analyzed and compared to identify breaths with low or high inspiratory effort. Results Pmusc, P0.1, Pressure Time Product and Flow Index differed between breaths with high, low and intermediate inspiratory effort, while RR, RR/VT and VT/kg of IBW did not differ in a statistically significant way. A Flow index higher than 4.5 identified breaths with high inspiratory effort [AUC 0.89 (CI 95% 0.85–0.93)], a Flow Index lower than 2.6 identified breaths with low inspiratory effort [AUC 0.80 (CI 95% 0.76–0.83)]. Conclusions Flow Index is accurate in detecting high and low spontaneous inspiratory effort during pressure support ventilation.

scholarly journals Flow Index: a novel, non-invasive, continuous, quantitative method to evaluate patient inspiratory effort during pressure support ventilation

Critical Care ◽  
2021 ◽  
Vol 25 (1) ◽  
Author(s):  
Filippo Albani ◽  
Luigi Pisani ◽  
Gianni Ciabatti ◽  
Federica Fusina ◽  
Barbara Buizza ◽  
...  
Keyword(s):  
Tidal Volume ◽  
Pressure Support Ventilation ◽  
Quantitative Method ◽  
Pressure Support ◽  
Esophageal Pressure ◽  
Inspiratory Effort ◽  
Inspiratory Flow ◽  
Flow Index ◽  
Support Ventilation ◽  
Non Invasive

Abstract Background The evaluation of patient effort is pivotal during pressure support ventilation, but a non-invasive, continuous, quantitative method to assess patient inspiratory effort is still lacking. We hypothesized that the concavity of the inspiratory flow-time waveform could be useful to estimate patient’s inspiratory effort. The purpose of this study was to assess whether the shape of the inspiratory flow, as quantified by a numeric indicator, could be associated with inspiratory effort during pressure support ventilation. Methods Twenty-four patients in pressure support ventilation were enrolled. A mathematical relationship describing the decay pattern of the inspiratory flow profile was developed. The parameter hypothesized to estimate effort was named Flow Index. Esophageal pressure, airway pressure, airflow, and volume waveforms were recorded at three support levels (maximum, minimum and baseline). The association between Flow Index and reference measures of patient effort (pressure time product and pressure generated by respiratory muscles) was evaluated using linear mixed effects models adjusted for tidal volume, respiratory rate and respiratory rate/tidal volume. Results Flow Index was different at the three pressure support levels and all group comparisons were statistically significant. In all tested models, Flow Index was independently associated with patient effort (p < 0.001). Flow Index prediction of inspiratory effort agreed with esophageal pressure-based methods. Conclusions Flow Index is associated with patient inspiratory effort during pressure support ventilation, and may provide potentially useful information for setting inspiratory support and monitoring patient-ventilator interactions.

Performance Characteristics of Five New Anesthesia Ventilators and Four Intensive Care Ventilators in Pressure-support Mode

2006 ◽  
Vol 105 (5) ◽  
pp. 944-952 ◽  
Author(s):  
Samir Jaber ◽  
Didier Tassaux ◽  
Mustapha Sebbane ◽  
Yvan Pouzeratte ◽  
Anne Battisti ◽  
...  
Keyword(s):  
Intensive Care Unit ◽  
Intensive Care ◽  
Pressure Support Ventilation ◽  
Gas Flow ◽  
Pressure Support ◽  
Inspiratory Effort ◽  
Performance Characteristics ◽  
Lung Model ◽  
Support Ventilation ◽  
Ventilation Performance

Background During the past few years, many manufacturers have introduced new modes of ventilation in anesthesia ventilators, especially partial-pressure modalities. The current bench test study was designed to compare triggering and pressurization of five new anesthesia ventilators with four intensive care unit ventilators. Methods Ventilators were connected to a two-compartment lung model. One compartment was driven by an intensive care unit ventilator to mimic "patient" inspiratory effort, whereas the other was connected to the tested ventilator. The settings of ventilators were positive end-expiratory pressures of 0 and 5 cm H2O, and pressure-support ventilation levels of 10, 15, and 20 cm H2O with normal and high "patient" inspiratory effort. For the anesthesia ventilators, all the measurements were obtained for a low (1 l/min) and a high (10 l/min) fresh gas flow. Triggering delay, triggering workload, and pressurization at 300 and 500 ms were analyzed. Results For the five tested anesthesia ventilators, the pressure-support ventilation modality functioned correctly. For inspiratory triggering, the three most recent anesthesia machines (Fabius, Drägerwerk AG, Lübeck, Germany; Primus, Drägerwerk AG; and Avance, GE-Datex-Ohemda, Munchen, Germany) had a triggering delay of less than 100 ms, which is considered clinically satisfactory and is comparable to intensive care unit machines. The use of positive end-expiratory pressure modified the quality of delivered pressure support for two anesthesia ventilators (Kion, Siemens AG, Munich, Germany; and Felix, Taema, Antony, France). Three of the five anesthesia ventilators exhibited pressure-support ventilation performance characteristics comparable to those of the intensive care unit machines. Increasing fresh gas flow (1 to 10 l/min) in the internal circuit did not influence the pressure-support ventilation performance of the anesthesia ventilators. Conclusion Regarding trigger sensitivity and the system's ability to meet inspiratory flow during pressure-supported breaths, the most recent anesthesia ventilators have comparable performances of recent-generation intensive care unit ventilators.

Respiratory response and inspiratory effort during pressure support ventilation in COPD patients

1995 ◽  
Vol 21 (11) ◽  
pp. 871-879 ◽  
Author(s):  
S. Nava ◽  
C. Bruschi ◽  
F. Rubini ◽  
A. Palo ◽  
G. Iotti ◽  
...  
Keyword(s):  
Pressure Support Ventilation ◽  
Pressure Support ◽  
Inspiratory Effort ◽  
Respiratory Response ◽  
Support Ventilation ◽  
Copd Patients

scholarly journals Automatic Adjustment of the Inspiratory Trigger and Cycling-Off Criteria Improved Patient-Ventilator Asynchrony During Pressure Support Ventilation

2021 ◽  
Vol 8 ◽  
Author(s):  
Ling Liu ◽  
Yue Yu ◽  
Xiaoting Xu ◽  
Qin Sun ◽  
Haibo Qiu ◽  
...  
Keyword(s):  
Pressure Support Ventilation ◽  
Pressure Support ◽  
Inspiratory Effort ◽  
Respiratory Drive ◽  
Breathing Patterns ◽  
Asynchrony Index ◽  
Support Ventilation ◽  
Automatic Adjustment ◽  
Adjustment System ◽  
Improve Patient

Background: Patient-ventilator asynchrony is common during pressure support ventilation (PSV) because of the constant cycling-off criteria and variation of respiratory system mechanical properties in individual patients. Automatic adjustment of inspiratory triggers and cycling-off criteria based on waveforms might be a useful tool to improve patient-ventilator asynchrony during PSV.Method: Twenty-four patients were enrolled and were ventilated using PSV with different cycling-off criteria of 10% (PS10), 30% (PS30), 50% (PS50), and automatic adjustment PSV (PSAUTO). Patient-ventilator interactions were measured.Results: The total asynchrony index (AI) and NeuroSync index were consistently lower in PSAUTO when compared with PS10, PS30, and PS50, (P &lt; 0.05). The benefit of PSAUTO in reducing the total AI was mainly because of the reduction of the micro-AI but not the macro-AI. PSAUTO significantly improved the relative cycling-off error when compared with prefixed controlled PSV (P &lt; 0.05). PSAUTO significantly reduced the trigger error and inspiratory effort for the trigger when compared with a prefixed trigger. However, total inspiratory effort, breathing patterns, and respiratory drive were not different among modes.Conclusions: When compared with fixed cycling-off criteria, an automatic adjustment system improved patient-ventilator asynchrony without changes in breathing patterns during PSV. The automatic adjustment system could be a useful tool to titrate more personalized mechanical ventilation.

Sign in / Sign up

Export Citation Format

Share Document