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Giorgio Conti - One of the best experts on this subject based on the ideXlab platform.

  • Remifentanil effects on respiratory drive and timing during Pressure Support Ventilation and neurally adjusted ventilatory assist
    Respiratory physiology & neurobiology, 2017
    Co-Authors: Roberta Costa, Paolo Navalesi, Gianmaria Cammarota, Federico Longhini, Giorgia Spinazzola, Flora Cipriani, Giuliano Ferrone, Olimpia Festa, Massimo Antonelli, Giorgio Conti
    Abstract:

    We assessed the effects of varying doses of remifentanil on respiratory drive and timing in patients receiving Pressure Support Ventilation (PSV) and Neurally Adjusted Ventilatory Assist (NAVA). Four incrementing remifentanil doses were randomly administered to thirteen intubated patients (0.03, 0.05, 0.08, and 0.1μg·Kg-1·min-1) during both PSV and NAVA. We measured the patient's (Ti/Ttotneu) and ventilator (Ti/Ttotmec) duty cycle, the Electrical Activity of the Diaphragm (EAdi), the inspiratory (Delaytrinsp) and expiratory (Delaytrexp) trigger delays and the Asynchrony Index (AI). Increasing doses of remifentanil did not modify EAdi, regardless the ventilatory mode. In comparison to baseline, remifentanil infusion >0.05μg/Kg-1/min-1 produced a significant reduction of Ti/Ttotneu and Ti/Ttotmec, by prolonging the expiratory time. Delaytrinsp and Delaytrexp were significantly shorter in NAVA, respect to PSV. AI was not influenced by the different doses of remifentanil, but it was significantly lower during NAVA, compared to PSV. In conclusion remifentanil did not affect the respiratory drive, but only respiratory timing, without differences between modes.

  • neurally adjusted ventilatory assist vs Pressure Support Ventilation in infants recovering from severe acute respiratory distress syndrome nested study
    Journal of Critical Care, 2014
    Co-Authors: Marco Piastra, Roberta Costa, Daniele De Luca, Alessandro Pizza, Renata De Sanctis, Laura Marzano, Daniele G Biasucci, Federico Visconti, Giorgio Conti
    Abstract:

    Abstract Objective Neurally adjusted ventilatory assist (NAVA) is a new ventilator modality with an innovative synchronization technique. Our aim is to verify if NAVA is feasible and safe in terms of physiological and clinical variables in infants recovering from severe acute respiratory distress syndrome (ARDS). Design This is a pilot nested study to help future trial design. Setting The study was performed in third-level academic pediatric intensive care units. Patients Infants affected by severe ARDS requiring high-frequency Ventilation and weaned with NAVA during 2010 were included. Controls (2:1 ratio) were ARDS infants weaned with Pressure Support Ventilation (PSV) during 2008-2009 matched for age, gas exchange impairment, and weight. Main outcome measures The main outcome measures were the physiological and ventilator parameters and the duration of ventilator Support in PSV or NAVA. Results Ten infants treated with NAVA and 20 with PSV were studied. Heart rate ( P P 2 /Fio 2 ratio decreased less in NAVA than in PSV ( P 2 ( P P = .001), as well as higher minute Ventilation ( P = .013). COMFORT score ( P = .004) and duration of Support were lower in NAVA than in PSV ( P = .011). Conclusions Neurally adjusted ventilatory assist is safe and suitable in infants recovering from severe ARDS. It could provide better results than PSV and is worth to be investigated in a multicenter randomized trial.

  • noninvasive Ventilation through a helmet in postextubation hypoxemic patients physiologic comparison between neurally adjusted ventilatory assist and Pressure Support Ventilation
    Intensive Care Medicine, 2011
    Co-Authors: Gianmaria Cammarota, Roberta Costa, Federico Longhini, Giorgio Conti, Rosanna Vaschetto, Davide Colombo, Francesco Della Corte, Carlo Olivieri, Emilia Turucz, Paolo Navalesi
    Abstract:

    Purpose Neurally adjusted ventilatory assist (NAVA) has been shown to improve patient–ventilator interaction and reduce asynchronies in intubated patients, as opposed to Pressure Support Ventilation (PSV). This is a short-term head-to-head physiologic comparison between PSV and NAVA in delivering noninvasive Ventilation through a helmet (h-NIV), in patients with postextubation hypoxemic acute respiratory failure.

  • influence of ventilator settings on patient ventilator synchrony during Pressure Support Ventilation with different interfaces
    Intensive Care Medicine, 2010
    Co-Authors: Roberta Costa, Paolo Navalesi, Giorgia Spinazzola, M Antonelli, G Ferrone, A Pellegrini, Franco Cavaliere, R Proietti, Giorgio Conti
    Abstract:

    To evaluate patient–ventilator interaction during Pressure Support Ventilation (PSV) delivered with three interfaces [endotracheal tube (ET), face mask (FM), and helmet (H)] at different pressurization times (Timepress), cycling-off flow thresholds (Trexp), and respiratory rates (RR) in a bench study, and with FM and H in a healthy volunteers study. Bench study using a mannequin connected to an active lung simulator, and human study including eight healthy volunteers. PSV was delivered through the three interfaces with three different RR in the bench study, and through FM and H at two different RR in the human study. The mechanical and the neural RR, Ti, Te, inspiratory trigger delay (Delaytrinsp), pressurization time, and expiratory trigger delay were randomly evaluated at various ventilator settings (Timepress/Trexp: 50%/25%, default setting; 20%/5%, slow setting; 80%/60%, fast setting). Bench study: patient–ventilator synchrony was significantly better with ET, with lower Delaytrinsp and higher time of assistance (P < 0.001); the combination Timepress/Trexp 20%/5% at RR 30 produced the worst interaction, with higher rate of wasted efforts (WE) compared with Timepress/Trexp 80%/60% (20%, 40%, and 50% of WE versus 0%, 16%, and 26% of all spontaneous breaths, with ET, FM, and H, respectively; P < 0.01). In both studies, compared with H, FM resulted in better synchrony. Patient–ventilator synchrony was significantly better with ET during the bench study; in the human study, FM outperformed H.

  • treatment of acute respiratory failure by helmet delivered non invasive Pressure Support Ventilation in children with acute leukemia a pilot study
    Intensive Care Medicine, 2004
    Co-Authors: Marco Piastra, M Antonelli, Antonio Chiaretti, G Polidori, Lorenzo Polidori, Giorgio Conti
    Abstract:

    To evaluate the feasibility of non-invasive Ventilation (NIV) through a new interface—the helmet—in the treatment of acute respiratory failure (ARF) in hematologic children. Observational, non-randomized report of four consecutive cases. Pediatric Intensive Care Unit in a university hospital. Four consecutive females (aged 9–17 years) affected by acute leukemia (3 acute lymphocytic leukemia [ALL], 1 acute myeloid leukemia [AML]) and with hypoxemic ARF (defined by severe dyspnea at rest, respiratory rate >30 breaths/min, PaO2:FiO2 <200 and active contraction of the accessory muscles). Pressure Support Ventilation was delivered via a helmet (CaStar,Starmed, Italy) by means of an ICU ventilator (Servo 300, Siemens Elema, Sweden). We evaluated the effect of Pressure Support Ventilation delivered by helmet on blood gases, respiratory rate, hemodynamics, patient tolerance, complication rate and outcome. An improvement of oxygenation was uniformly observed within the first 3 h after admission. The helmet was well tolerated by all children. No complication was observed. Two patients were discharged from the PICU in stable clinical conditions, whereas the remaining two children overcame the respiratory distress but had non-respiratory complications and eventually died. Non-invasive Ventilation via the helmet can offer effective ventilatory Support and improve gas exchange in the treatment of ARF in pediatric hematologic patients. As already shown in adults, NIV may decrease the risk of life-threatening complications associated with invasive mechanical Ventilation (MV), also in children with hematologic malignancies; moreover, it offers the possibility of an earlier approach to respiratory failure in this patient subset.

Christer Sinderby - One of the best experts on this subject based on the ideXlab platform.

  • a diaphragmatic electrical activity based optimization strategy during Pressure Support Ventilation improves synchronization but does not impact work of breathing
    Critical Care, 2017
    Co-Authors: Christer Sinderby, Francois Beloncle, Nuttapol Rittayamai, Lise Piquilloud, Hadrien Roze
    Abstract:

    Poor patient-ventilator synchronization is often observed during Pressure Support Ventilation (PSV) and has been associated with prolonged duration of mechanical Ventilation and poor outcome. Diaphragmatic electrical activity (Eadi) recorded using specialized nasogastric tubes is a surrogate of respiratory brain stem output. This study aimed at testing whether adapting ventilator settings during PSV using a protocolized Eadi-based optimization strategy, or Eadi-triggered and -cycled assisted Pressure Ventilation (or PSVN) could (1) improve patient-ventilator interaction and (2) reduce or normalize patient respiratory effort as estimated by the work of breathing (WOB) and the Pressure time product (PTP). This was a prospective cross-over study. Patients with a known chronic pulmonary obstructive or restrictive disease, asynchronies or suspected intrinsic positive end-expiratory Pressure (PEEP) who were ventilated using PSV were enrolled in the study. Four different ventilator settings were sequentially applied for 15 minutes (step 1: baseline PSV as set by the clinician, step 2: Eadi-optimized PSV to adjust PS level, inspiratory trigger, and cycling settings, step 3: step 2 + PEEP adjustment, step 4: PSVN). The same settings as step 3 were applied again after step 4 to rule out a potential effect of time. Breathing pattern, trigger delay (Td), inspiratory time in excess (Tiex), Pressure-time product (PTP), and work of breathing (WOB) were measured at the end of each step. Eleven patients were enrolled in the study. Eadi-optimized PSV reduced Td without altering Tiex in comparison with baseline PSV. PSVN reduced Td and Tiex in comparison with baseline and Eadi-optimized PSV. Respiratory pattern did not change during the four steps. The improvement in patient-ventilator interaction did not lead to changes in WOB or PTP. Eadi-optimized PSV allows improving patient ventilator interaction but does not alter patient effort in patients with mild asynchrony. Clinicaltrials.gov identifier: NCT 02067403 . Registered 7 February 2014.

  • automated patient ventilator interaction analysis during neurally adjusted non invasive Ventilation and Pressure Support Ventilation in chronic obstructive pulmonary disease
    Critical Care, 2014
    Co-Authors: Jonne Doorduin, Christer Sinderby, Jennifer Beck, Johannes G Van Der Hoeven, Leo M A Heunks
    Abstract:

    Delivering synchronous assist during non-invasive Ventilation (NIV) is challenging with flow- or Pressure-controlled ventilators, especially in patients with chronic obstructive pulmonary disease (COPD). Neurally adjusted ventilatory assist (NAVA) uses diaphragm electrical activity (EAdi) to control the ventilator. We evaluated patient-ventilator interaction in patients with COPD during NIV with Pressure Support Ventilation (PSV) and NAVA using a recently introduced automated analysis. Twelve COPD patients underwent three 30-minute trials: 1) PSV with dedicated NIV ventilator (NIV-PSVVision), 2) PSV with intensive care unit (ICU) ventilator (NIV-PSVServo-I), and 3) with NIV-NAVA. EAdi, flow, and airway Pressure were recorded. Patient-ventilator interaction was evaluated by comparing airway Pressure and EAdi waveforms with automated computer algorithms. The NeuroSync index was calculated as the percentage of timing errors between airway Pressure and EAdi. The NeuroSync index was higher (larger error) for NIV-PSVVision (24 (IQR 15 to 30) %) and NIV-PSVServo-I (21 (IQR 15 to 26) %) compared to NIV-NAVA (5 (IQR 4 to 7) %; P <0.001). Wasted efforts, trigger delays and cycling-off errors were less with NAVA (P <0.05 for all). The NeuroSync index and the number of wasted efforts were strongly correlated (r2 = 0.84), with a drastic increase in wasted efforts after timing errors reach 20%. In COPD patients, non-invasive NAVA improves patient-ventilator interaction compared to PSV, delivered either by a dedicated or ICU ventilator. The automated analysis of patient-ventilator interaction allowed for an objective detection of patient-ventilator interaction during NIV. In addition, we found that progressive mismatch between neural effort and pneumatic timing is associated with wasted efforts.

  • patient ventilator interaction during Pressure Support Ventilation and neurally adjusted ventilatory assist
    Critical Care Medicine, 2010
    Co-Authors: Jadranka Spahija, Jennifer Beck, Michel De Marchie, Martin Albert, Patrick Bellemare, Stephane Delisle, Christer Sinderby
    Abstract:

    Objective:To compare the effect of Pressure Support Ventilation and neurally adjusted ventilatory assist on breathing pattern, patient-ventilator synchrony, diaphragm unloading, and gas exchange. Increasing the level of Pressure Support Ventilation can increase tidal volume, reduce respiratory rate,

  • closed loop control of respiratory drive using Pressure Support Ventilation target drive Ventilation
    American Journal of Respiratory and Critical Care Medicine, 2005
    Co-Authors: Jadranka Spahija, Jennifer Beck, Michel De Marchie, Alain S Comtois, Christer Sinderby
    Abstract:

    By using diaphragm electrical activity (multiple-array esophageal electrode) as an index of respiratory drive, and allowing such activity above or below a preset target range to indicate an increased or reduced demand for ventilatory assistance (target drive Ventilation), we evaluated whether the level of Pressure-Support Ventilation can be automatically adjusted in response to exercise-induced changes in ventilatory demand. Eleven healthy individuals breathed through a circuit (18 cm H2O/L/second inspiratory resistance at 1 L/second flow; 0.5-1.0 L/second expiratory flow limitation) connected to a modified ventilator. Subjects breathed for 6-minute periods at rest and during 20 and 40 W of bicycle exercise, with and without target drive Ventilation (the target was set to 60% of the increase in diaphragm electrical activity observed between rest and 20 W of unassisted exercise). With target drive Ventilation during exercise, the level of Pressure-Support Ventilation was automatically increased, reaching 13.3 +/- 4.0 and 20.3 +/- 2.8 cm H2O during 20- and 40-W exercise, respectively, whereas diaphragm electrical activity was reduced to a level within the target range. Both diaphragmatic Pressure-time product and end-tidal CO2 were significantly reduced with target drive Ventilation at the end of the 20- (p < 0.01) and 40-W (p < 0.001) exercise periods. Minute Ventilation was not altered. These results demonstrate that target drive Ventilation can automatically adjust Pressure-Support Ventilation, maintaining a constant neural drive and compensating for changes in respiratory demand.

  • electrical activity of the diaphragm during Pressure Support Ventilation in acute respiratory failure
    American Journal of Respiratory and Critical Care Medicine, 2001
    Co-Authors: Jennifer Beck, Paolo Navalesi, Stewart B Gottfried, Yoanna Skrobik, Norman Comtois, Mauro Rossini, Christer Sinderby
    Abstract:

    We compared crural diaphragm electrical activity (EAdi) with transdiaphragmatic Pressure (Pdi) during varying levels of Pressure Support Ventilation (PS) in 13 intubated patients. With changing PS, we found no evidence for changes in neuromechanical coupling of the diaphragm. From lowest to highest PS (2 cm H2O ± 4 to 20 cm H2O ± 7), tidal volume increased from 430 ml ± 180 to 527 ml ± 180 (p < 0.001). The inspiratory volume calculated during the period when EAdi increased to its peak did not change from 276 ± 147 to 277 ± 162 ml, p = 0.976. Respiratory rate decreased from 23.9 ( ± 7) to 21.3 ( ± 7) breaths/min (p = 0.015). EAdi and Pdi decreased proportionally by adding PS (r = 0.84 and r = 0.90, for mean and peak values, respectively). Mean and peak EAdi decreased (p < 0.001) by 33 ± 21% (mean ± SD) and 37 ± 23% with the addition of 10 cm H2O of PS, similar to the decrease in the mean and peak Pdi (p < 0.001) observed (34 ± 36 and 35 ± 23%). We also found that ventilator assist continued during the diap...

Pierre Pasquis - One of the best experts on this subject based on the ideXlab platform.

  • effects of Pressure ramp slope values on the work of breathing during Pressure Support Ventilation in restrictive patients
    Critical Care Medicine, 1999
    Co-Authors: G Bonmarchand, Virginie Chevron, J F Menard, Christophe Girault, Fabienne Moritzberthelot, Pierre Pasquis, Jacques Leroy
    Abstract:

    OBJECTIVE To investigate, in restrictive patients, the influence of Pressure ramp slope values on the efficacy of Pressure Support Ventilation. DESIGN Prospective study. SETTING A university hospital medical intensive care unit. PATIENTS Twelve intubated restrictive patients. INTERVENTIONS Patients were randomly assigned to four sequences in which the values of the slope of the Pressure ramp increase were modulated so that the plateau Pressure was reached within a predetermined time: 0.1, 0.50, 1, or 1.50 secs. The more rapidly the Pressure plateau was achieved, the higher was the initial flow rate. For convenience, these four different ventilatory settings were termed T 0.1, T 0.5, T 1, and T 1.5. MEASUREMENTS AND MAIN RESULTS We measured the following parameters 10 mins after application of each Pressure ramp slope: inspiratory work of breathing, breathing pattern, and intrinsic PEEP (PEEPi). Work of breathing was evaluated using Campbell's diagram, and expressed as a percentage of the values observed under spontaneous Ventilation. A marked interindividual variation of the values for work of breathing was observed under spontaneous Ventilation; the mean value for work of breathing was 1.97 +/- 0.82 joule/L, with a range of 1.22 to 4.10 joule/L. Comparison between the means for each sequence and each variable measured was performed by two-way analysis of variance with internal comparisons between sequences by Duncan's test. Between the first (T 0.1) and the last (T 1.5) sequence, the reduction of values of the Pressure ramp slope induced a progressive increase in the values for work of breathing, regardless of the mode of expression (in joule, joule/L, or joule/min). The values for work of breathing (joule/ L), expressed as a percentage of the values observed under spontaneous Ventilation, increased from 44.2 +/- 14.4% to 78.3 +/- 17.8% (p < .001). In contrast, the reduction of the Pressure ramp slope values and initial flow rate did not induce any significant change in tidal volume, respiratory frequency, and PEEPi. CONCLUSION Among the four tested slope values, the steepest was that which induced the lowest possible work of breathing in restrictive patients ventilated by Pressure Support Ventilation. In this type of patient, we therefore suggest that the programmed Pressure value should be reached by using a steep Pressure ramp slope.

  • comparative physiologic effects of noninvasive assist control and Pressure Support Ventilation in acute hypercapnic respiratory failure
    Chest, 1997
    Co-Authors: Christophe Girault, G Bonmarchand, Virginie Chevron, Jacques Leroy, Jeanchristophe Richard, Fabienne Tamion, Pierre Pasquis
    Abstract:

    Study objective To compare the effects of noninvasive assist-control Ventilation (ACV) and Pressure Support Ventilation (PSV) by nasal mask on respiratory physiologic parameters and comfort in acute hypercapnic respiratory failure (AHRF). Design A prospective randomized study. Setting A medical ICU. Patients and interventions Fifteen patients with COPD and AHRF were consecutively and randomly assigned to two noninvasive Ventilation (NIV) sequences with ACV and PSV mode, spontaneous breathing (SR) via nasal mask being used as control. ACV and PSV settings were always subsequently adjusted according to patient's tolerance and air leaks. Fraction of inspired oxygen did not change between the sequences. Measurements and results ACV and PSV mode strongly decreased the inspiratory effort in comparison with SR. The total inspiratory work of breathing (WOBinsp) expressed as WOBinsp/tidal volume (VT) and WOBinsp/respiratory rate (RR), the Pressure time product (PTP), and esophageal Pressure variations (ΔPes) were the most discriminant parameters (p 32% as compared with control values (p Conclusions During NIV for AHRF using settings adapted to patient's clinical tolerance and mask air leaks, both ACV and PSV mode provide respiratory muscle rest and similarly improve breathing pattern and gas exchange. However, these physiologic effects are achieved with a lower inspiratory workload but at the expense of a higher respiratory discomfort with ACV than with PSV mode.

  • increased initial flow rate reduces inspiratory work of breathing during Pressure Support Ventilation in patients with exacerbation of chronic obstructive pulmonary disease
    Intensive Care Medicine, 1996
    Co-Authors: G Bonmarchand, Virginie Chevron, Christophe Girault, Jacques Leroy, C Chopin, D Jusserand, F Moritz, Pierre Pasquis
    Abstract:

    To investigate whether the level of initial flow rate alters the work of breathing in chronic obstructive pulmonary disease (COPD) patients ventilated in Pressure Support Ventilation (PSV). Prospective study. Medical ICU in University hospital. Eleven intubated COPD patients. We modulated the initial flow rate in order to achieve seven different sequences. In each sequence, the plateau Pressure was reached within a predetermined time: 0.1, 0.25, 0.50, 0.75, 1, 1.25 or 1.50 s. The more rapidly the Pressure plateau was achieved, the higher was the initial flow rate. In each patient, the Pressure Support level was an invariable parameter. The order of the seven sequences for each patient was determined randomly. Ten minutes after application of each initial flow rate, we measured the following parameters: inspiratory work of breathing, electromyogram (EMG) of the diaphragm (EMGdi), breathing pattern, and intrinsic positive end-expiratory Pressure (PEEPi). Comparison between the means for each sequence and each variable measured was performed by two-way analysis of variance with internal comparisons between sequences by Duncan's test. The reduction of the initial flow rate induced a progressive increase in the values of the work of breathing, EMGdi, and mouth occlusion Pressure (P 0.1). In contrast, the reduction of the initial flow rate did not induce any significant change in tidal volume, respiratory frequency or PEEPi. As the objective of PSV is to reduce the work of breathing, it seems logical to use the highest initial flow rate to induce the lowest possible work of breathing in COPD ventilated patients.

  • increased initial flow rate reduces inspiratory work of breathing during Pressure Support Ventilation in patients with exacerbation of chronic obstructive pulmonary disease
    Intensive Care Medicine, 1996
    Co-Authors: G Bonmarchand, Virginie Chevron, Christophe Girault, Jacques Leroy, C Chopin, D Jusserand, F Moritz, Pierre Pasquis
    Abstract:

    Objective To investigate whether the level of initial flow rate alters the work of breathing in chronic obstructive pulmonary disease (COPD) patients ventilated in Pressure Support Ventilation (PSV).

Paolo Navalesi - One of the best experts on this subject based on the ideXlab platform.

  • Remifentanil effects on respiratory drive and timing during Pressure Support Ventilation and neurally adjusted ventilatory assist
    Respiratory physiology & neurobiology, 2017
    Co-Authors: Roberta Costa, Paolo Navalesi, Gianmaria Cammarota, Federico Longhini, Giorgia Spinazzola, Flora Cipriani, Giuliano Ferrone, Olimpia Festa, Massimo Antonelli, Giorgio Conti
    Abstract:

    We assessed the effects of varying doses of remifentanil on respiratory drive and timing in patients receiving Pressure Support Ventilation (PSV) and Neurally Adjusted Ventilatory Assist (NAVA). Four incrementing remifentanil doses were randomly administered to thirteen intubated patients (0.03, 0.05, 0.08, and 0.1μg·Kg-1·min-1) during both PSV and NAVA. We measured the patient's (Ti/Ttotneu) and ventilator (Ti/Ttotmec) duty cycle, the Electrical Activity of the Diaphragm (EAdi), the inspiratory (Delaytrinsp) and expiratory (Delaytrexp) trigger delays and the Asynchrony Index (AI). Increasing doses of remifentanil did not modify EAdi, regardless the ventilatory mode. In comparison to baseline, remifentanil infusion >0.05μg/Kg-1/min-1 produced a significant reduction of Ti/Ttotneu and Ti/Ttotmec, by prolonging the expiratory time. Delaytrinsp and Delaytrexp were significantly shorter in NAVA, respect to PSV. AI was not influenced by the different doses of remifentanil, but it was significantly lower during NAVA, compared to PSV. In conclusion remifentanil did not affect the respiratory drive, but only respiratory timing, without differences between modes.

  • effects of propofol on patient ventilator synchrony and interaction during Pressure Support Ventilation and neurally adjusted ventilatory assist
    Critical Care Medicine, 2014
    Co-Authors: Rosanna Vaschetto, Gianmaria Cammarota, Federico Longhini, Davide Colombo, Francesca Grossi, Andrea Giovanniello, Francesco Della Corte, Paolo Navalesi
    Abstract:

    OBJECTIVES Evaluating the physiologic effects of varying depths of propofol sedation on patient-ventilator interaction and synchrony during Pressure Support Ventilation and neurally adjusted ventilatory assist. DESIGN Prospective crossover randomized controlled trial. SETTING University hospital ICU. PATIENTS Fourteen intubated patients mechanically ventilated for acute respiratory failure. INTERVENTIONS Six 25-minute trials randomly performed applying both Pressure Support Ventilation and neurally adjusted ventilatory assist during wakefulness and with two doses of propofol, administered by Target Control Infusion, determining light (1.26 ± 0.35 μg/mL) and deep (2.52 ± 0.71 μg/mL) sedation, as defined by the bispectral index and Ramsay Sedation Scale. MEASUREMENTS AND MAIN RESULTS We measured electrical activity of the diaphragm to assess neural drive and calculated its integral over time during 1 minute (∫electrical activity of the diaphragm/min) to estimate diaphragm energy expenditure (effort), arterial blood gases, airway Pressure, tidal volume and its coefficient of variation, respiratory rate, neural timing components, and calculated the ineffective triggering index. Increasing the depth of sedation did not cause significant modifications of respiratory timing, while determined a progressive significant decrease in neural drive (with both modes) and effort (in Pressure Support Ventilation only). In Pressure Support Ventilation, the difference in ineffective triggering index between wakefulness and light sedation was negligible (from 5.9% to 7.6%, p = 0.97); with deep sedation, however, ineffective triggering index increased up to 21.8% (p < 0.0001, compared to both wakefulness and light sedation). With neurally adjusted ventilatory assist, ineffective triggering index fell to 0%, regardless of the depth of sedation. With both modes, deep sedation caused a significant increase in PaCO2, which resulted, however, from different breathing patterns and patient-ventilator interactions. CONCLUSIONS In Pressure Support Ventilation, deep propofol sedation increased asynchronies, while light sedation did not. Propofol reduced the respiratory drive, while breathing timing was not significantly affected. Gas exchange and breathing pattern were also influenced by propofol infusion to an extent that varied with the depth of sedation and the mode of Ventilation.

  • noninvasive Ventilation through a helmet in postextubation hypoxemic patients physiologic comparison between neurally adjusted ventilatory assist and Pressure Support Ventilation
    Intensive Care Medicine, 2011
    Co-Authors: Gianmaria Cammarota, Roberta Costa, Federico Longhini, Giorgio Conti, Rosanna Vaschetto, Davide Colombo, Francesco Della Corte, Carlo Olivieri, Emilia Turucz, Paolo Navalesi
    Abstract:

    Purpose Neurally adjusted ventilatory assist (NAVA) has been shown to improve patient–ventilator interaction and reduce asynchronies in intubated patients, as opposed to Pressure Support Ventilation (PSV). This is a short-term head-to-head physiologic comparison between PSV and NAVA in delivering noninvasive Ventilation through a helmet (h-NIV), in patients with postextubation hypoxemic acute respiratory failure.

  • influence of ventilator settings on patient ventilator synchrony during Pressure Support Ventilation with different interfaces
    Intensive Care Medicine, 2010
    Co-Authors: Roberta Costa, Paolo Navalesi, Giorgia Spinazzola, M Antonelli, G Ferrone, A Pellegrini, Franco Cavaliere, R Proietti, Giorgio Conti
    Abstract:

    To evaluate patient–ventilator interaction during Pressure Support Ventilation (PSV) delivered with three interfaces [endotracheal tube (ET), face mask (FM), and helmet (H)] at different pressurization times (Timepress), cycling-off flow thresholds (Trexp), and respiratory rates (RR) in a bench study, and with FM and H in a healthy volunteers study. Bench study using a mannequin connected to an active lung simulator, and human study including eight healthy volunteers. PSV was delivered through the three interfaces with three different RR in the bench study, and through FM and H at two different RR in the human study. The mechanical and the neural RR, Ti, Te, inspiratory trigger delay (Delaytrinsp), pressurization time, and expiratory trigger delay were randomly evaluated at various ventilator settings (Timepress/Trexp: 50%/25%, default setting; 20%/5%, slow setting; 80%/60%, fast setting). Bench study: patient–ventilator synchrony was significantly better with ET, with lower Delaytrinsp and higher time of assistance (P < 0.001); the combination Timepress/Trexp 20%/5% at RR 30 produced the worst interaction, with higher rate of wasted efforts (WE) compared with Timepress/Trexp 80%/60% (20%, 40%, and 50% of WE versus 0%, 16%, and 26% of all spontaneous breaths, with ET, FM, and H, respectively; P < 0.01). In both studies, compared with H, FM resulted in better synchrony. Patient–ventilator synchrony was significantly better with ET during the bench study; in the human study, FM outperformed H.

  • electrical activity of the diaphragm during Pressure Support Ventilation in acute respiratory failure
    American Journal of Respiratory and Critical Care Medicine, 2001
    Co-Authors: Jennifer Beck, Paolo Navalesi, Stewart B Gottfried, Yoanna Skrobik, Norman Comtois, Mauro Rossini, Christer Sinderby
    Abstract:

    We compared crural diaphragm electrical activity (EAdi) with transdiaphragmatic Pressure (Pdi) during varying levels of Pressure Support Ventilation (PS) in 13 intubated patients. With changing PS, we found no evidence for changes in neuromechanical coupling of the diaphragm. From lowest to highest PS (2 cm H2O ± 4 to 20 cm H2O ± 7), tidal volume increased from 430 ml ± 180 to 527 ml ± 180 (p < 0.001). The inspiratory volume calculated during the period when EAdi increased to its peak did not change from 276 ± 147 to 277 ± 162 ml, p = 0.976. Respiratory rate decreased from 23.9 ( ± 7) to 21.3 ( ± 7) breaths/min (p = 0.015). EAdi and Pdi decreased proportionally by adding PS (r = 0.84 and r = 0.90, for mean and peak values, respectively). Mean and peak EAdi decreased (p < 0.001) by 33 ± 21% (mean ± SD) and 37 ± 23% with the addition of 10 cm H2O of PS, similar to the decrease in the mean and peak Pdi (p < 0.001) observed (34 ± 36 and 35 ± 23%). We also found that ventilator assist continued during the diap...

Peter M Spieth - One of the best experts on this subject based on the ideXlab platform.