Pressure Support Ventilation Group Research Articles

Nocturnal Pressure Controlled Ventilation Improves Sleep Efficiency in Patients Receiving Mechanical Ventilation.

Patients receiving mechanical ventilation commonly experience sleep fragmentation. The present meta-analysis compared the effects of pressure controlled ventilation (PCV) and pressure support ventilation (PSV) on sleep quality. We conducted a search of the PubMed, Embase, and Cochrane Library databases for studies published before November 2023. In this meta-analysis, individual effect sizes were standardized, and the pooled effect size was determined by using random-effects models. The primary outcome was sleep efficiency. The secondary outcomes were wakefulness, percentages of REM (rapid eye movement) sleep and stages 3 and 4 non-REM sleep, the fragmentation index, and the incidence of apneic events. This meta-analysis examined 4 trials that involved 67 subjects. Sleep efficiency was significantly higher in the PCV group than in the PSV group (mean difference 15.57%, 95% CI 8.54%-22.59%). Wakefulness was significantly lower in the PCV group than in the PSV group (mean difference -18.67%, 95% CI -30.29% to -7.04%). The percentage of REM sleep was significantly higher in the PCV group than in the PSV group (mean difference 2.32%, 95% CI 0.20%-4.45%). Among the subjects with a tendency to develop sleep apnea, the fragmentation index was significantly lower in those receiving PCV than PSV (mean difference -40.00%, 95% CI -51.12% to -28.88%). The incidence of apneic events was significantly lower in the PCV group than in the PSV group (risk ratio 0.06, 95% CI 0.01-0.45). Compared with PSV, PCV may improve sleep quality in patients receiving nocturnal mechanical ventilation.

Comparing lung aeration and respiratory effort using two different spontaneous breathing trial: T-piece vs pressure support ventilation

ObjectiveTo assess the changes in lung aeration and respiratory effort generated by two different spontaneous breathing trial (SBT): T-piece (T-T) vs pressure support ventilation (PSV). DesignProspective, interventionist and randomized study. SettingIntensive Care Unit (ICU) of Hospital del Mar. ParticipantsForty-three ventilated patients for at least 24 h and considered eligible for an SBT were included in the study between October 2017 and March 2020. Interventions30-min SBT with T-piece (T-T group, 20 patients) or 8-cmH2O PSV and 5-cmH2O positive end expiratory pressure (PSV group, 23 patients). Main variables of interestDemographics, clinical data, physiological variables, lung aeration evaluated with electrical impedance tomography (EIT) and lung ultrasound (LUS), and respiratory effort using diaphragmatic ultrasonography (DU) were collected at different timepoints: basal (BSL), end of SBT (EoSBT) and one hour after extubation (OTE). ResultsThere were a loss of aeration measured with EIT and LUS in the different study timepoints, without statistical differences from BSL to OTE, between T-T and PSV [LUS: 3 (1, 5.5) AU vs 2 (1, 3) AU; p = 0.088; EELI: −2516.41 (−5871.88, 1090.46) AU vs −1992.4 (−3458.76, −5.07) AU; p = 0.918]. Percentage of variation between BSL and OTE, was greater when LUS was used compared to EIT (68.1% vs 4.9%, p ≤ 0.001). Diaphragmatic excursion trend to decrease coinciding with a loss of aeration during extubation. ConclusionT-T and PSV as different SBT strategies in ventilated patients do not show differences in aeration loss, nor estimated respiratory effort or tidal volume measured by EIT, LUS and DU.

Comparison of clinical outcomes in critical patients undergoing different mechanical ventilation modes: a systematic review and network meta-analysis.

To evaluate the effects of different mechanical ventilation modes on critical patients. PubMed, Embase, Web of science, and Cochrane Library databases were searched from their inception to November 15, 2022 for randomized controlled trials on the application of different mechanical ventilation modes in critical patients. Two researchers independently screened the literature, extracted data, and assessed the risk of bias in the included studies. R4.2.1 was used for this network meta-analysis. Twenty-eight RCTs involving 3,189 patients were included. The interventions in these RCTs included NAVA (neurally adjusted ventilatory assist), PAV (proportional assist ventilation), ASV (adaptive support ventilation), Smartcare/PS (Smartcare/pressure support), PSV (pressure support ventilation), PSV_ATC (pressure support ventilation_automatic tube compensation), and SIMV (synchronized intermittent mandatory ventilation). The network meta-analysis showed that, compared with the PSV group, there was no significant difference in duration of mechanical ventilation, duration of ICU stay, and hospital stay between NAVA, SIMV, AVS, PAV, Smartcare/PS, and PSV_ATC groups. Compared with PSV, PAV improved the success rate of withdrawal of ventilator [OR = 3.07, 95%CI (1.21, 8.52)]. Compared with PSV and PAV, NAVA reduced mortality in the ICU [OR = 0.63, 95%CI (0.43, 0.93); OR = 0.45, 95%CI (0.21, 0.97)]. NAVA can reduce mortality in ICU, and PAV may increase the risk of withdrawal of the ventilator. There was no significant difference between PSV and other mechanical ventilation modes (NAVA, SIMV, AVS, PAV, Smartcare/PS, and PSV_ATC) in the duration of mechanical ventilation, duration of ICU stay, or hospital stay. Due to the limitations, more high-quality studies are needed to verify these findings.

Effect of neurally adjusted ventilatory assist ventilation in severe neurological cerebrovascular diseases patients undergoing mechanical ventilation

To explore the prognostic effect and safety of neurally adjusted ventilatory assist (NAVA) mode on the patients with severe neurological cerebrovascular disease undergoing mechanical ventilation. A prospective study was conducted. Fifty-four patients with cerebrovascular disease undergoing mechanical ventilation admitted to the neurosurgery intensive care unit (NSICU) of the First Affiliated Hospital of Wannan Medical College (Yijishan Hospital) from December 2020 to May 2022 were enrolled. They were divided into NAVA group and pressure support ventilation (PSV) group by computer random number generator with 27 patients in each group. The ventilation time of the two groups was ≥ 72 hours. The general basic data of the two groups were recorded. The time without mechanical ventilation 28 days after enrollment, total length of mechanical ventilation, survival rate of 90 days after enrollment, length of NSICU stay, total length of hospital stay, NSICU mortality, in-hospital mortality, Glasgow outcome score (GOS), complications related to mechanical ventilation, and changes of respiratory mechanics indexes, arterial blood gases, vital signs, and diaphragm function indexes were observed. The time without mechanical ventilation 28 days after enrollment in the NAVA group was significantly longer than that in the PSV group [days: 22 (15, 26) vs. 6 (0, 23), P < 0.05]. However, there were no significant differences in the total length of mechanical ventilation, 90-day survival rate, length of NSICU stay, total length of hospital stay, NSICU mortality, in-hospital mortality, GOS score, and incidence of mechanical ventilator-related complications between the two groups. In terms of respiratory mechanics parameters, the expiratory tidal volume (VTe) on 3 days after mechanical ventilation of patients in the NAVA group was significantly lower than that on 1 day and 2 days, and significantly lower than that in the PSV group [mL: 411.0 (385.2, 492.6) vs. 489.0 (451.8, 529.4), P < 0.01]. Minute ventilation (MV) at 2 days and 3 days in the NAVA group was significantly higher than that at 1 day, and significantly higher than that in the PSV group at 2 days [L/min: 9.8 (8.4, 10.9) vs. 7.8 (6.5, 9.8), P < 0.01], while there was no significant change of MV in the PSV group. At 1 day, peak airway pressure (Ppeak) and mean airway pressure (Pmean) in the NAVA group were significantly lower than those in the PSV group [Ppeak (cmH2O, 1 cmH2O ≈ 0.098 kPa): 14.0 (12.2, 17.0) vs. 16.6 (15.0, 17.4), Pmean (cmH2O): 7.0 (6.2, 7.9) vs. 8.0 (7.0, 8.2), both P < 0.05]. However, there was no significant difference in the Ppeak or Pmean at 2 days and 3 days between the two groups. In terms of arterial blood gas, there was no significant difference in pH value between the two groups, but with the extension of mechanical ventilation time, the pH value at 3 days of the two groups was significantly higher than that at 1 day. Arterial partial pressure of oxygen (PaO2) at 1 day in the NAVA group was significantly lower than that in the PSV group [mmHg (1 mmHg ≈ 0.133 kPa): 122.01±37.77 vs. 144.10±40.39, P < 0.05], but there was no significant difference in PaO2 at 2 days and 3 days between the two groups. There was no significant difference in arterial partial pressure of carbon dioxide (PaCO2) or oxygenation index (PaO2/FiO2) between the two groups. In terms of vital signs, the respiratory rate (RR) at 1, 2, and 3 days of the NAVA group was significantly higher than that of the PSV group [times/min: 19.2 (16.0, 25.2) vs. 15.0 (14.4, 17.0) at 1 day, 21.4 (16.4, 26.0) vs. 15.8 (14.0, 18.6) at 2 days, 20.6 (17.0, 23.0) vs. 16.7 (15.0, 19.0) at 3 days, all P < 0.01]. In terms of diaphragm function, end-inspiratory diaphragm thickness (DTei) at 3 days in the NAVA group was significantly higher than that in the PSV group [cm: 0.26 (0.22, 0.29) vs. 0.22 (0.19, 0.26), P < 0.05]. There was no significant difference in end-expiratory diaphragm thickness (DTee) between the two groups. The diaphragm thickening fraction (DTF) at 2 days and 3 days in the NAVA group was significantly higher than that in the PSV group [(35.18±12.09)% vs. (26.88±8.33)% at 2 days, (35.54±13.40)% vs. (24.39±9.16)% at 3 days, both P < 0.05]. NAVA mode can be applied in patients with neuro-severe cerebrovascular disease, which can prolong the time without mechanical ventilation support and make patients obtain better lung protective ventilation. At the same time, it has certain advantages in avoiding ventilator-associated diaphragm dysfunction and improving diaphragm function.

Comparison of pressure support ventilation and proportional assist ventilation plus for weaning from mechanical ventilation in critically ill patients

Background: Pressure support ventilation (PSV) is a widely used weaning mode that provides varying amount of support with changing lung characteristics. Proportional-assist ventilation plus (PAV+) is a new mode that automatically adjusts to changes in the respiratory system. Aim: This study compared PSV and PAV+ for weaning from mechanical ventilation. Methods: This was a prospective, randomised, control study enrolling 23 adult patients, mechanically ventilated for at least 48 h after passing SBT criteria and a PSV trial of 30 min. They were randomised to receive either PAV+ (Group 1) or PSV (Group 2). A washout time of 30 min was given for patients in either of the group in order to nullify the effect of the previous PSV mode. Two arterial blood gas samples were taken, during the assessment of SBT readiness, and after 60 min on the randomised weaning mode. Clinical signs of respiratory distress and objective weaning criteria were noted. Success and duration of weaning, rapid shallow breathing index (RSBI), rapid shallow breathing index rate (RSBI rate), haemodynamic and respiratory parameters were noted. Results: 13 patients were randomised to PAV+ group; 10 patients to PSV group. Demographic data were similar in both groups. RSBI, RSBI rate, arterial blood gas analysis, peak and mean inspiratory pressure were not different in either group. The average length of ICU stay, duration to wean and days to extubate were almost similar in both groups. Conclusion: Both PAV+ mode and PSV can be used with equal efficiency in patients ready for weaning.

Spontaneous-Breathing Trials with Pressure-Support Ventilation or a T-Piece

BackgroundSpontaneous-breathing trials can be performed with the use of either pressure-support ventilation (PSV) or a T-piece. Whether PSV trials may result in a shorter time to tracheal extubation than T-piece trials, without resulting in a higher risk of reintubation, among patients who have a high risk of extubation failure is unknown.MethodsIn this multicenter, open-label trial, we randomly assigned patients who had a high risk of extubation failure (i.e., were >65 years of age or had an underlying chronic cardiac or respiratory disease) to undergo spontaneous-breathing trials performed with the use of either PSV (with a pressure-support level of 8 cm of water and no positive end-expiratory pressure) or a T-piece. The primary outcome was the total time without exposure to invasive ventilation (reported as the number of ventilator-free days) at day 28 after the initial spontaneous-breathing trial. Secondary outcomes included extubation within 24 hours and extubation within 7 days after the initial spontaneous-breathing trial, as well as reintubation within 7 days after extubation.ResultsA total of 969 patients (484 in the PSV group and 485 in the T-piece group) were included in the analysis. At day 28, the median number of ventilator-free days was 27 (interquartile range, 24 to 27) in the PSV group and 27 (interquartile range, 23 to 27) in the T-piece group (difference, 0 days; 95% confidence interval [CI], −0.5 to 1; P=0.31). Extubation was performed within 24 hours in 376 patients (77.7%) in the PSV group and in 350 patients (72.2%) in the T-piece group (difference, 5.5 percentage points; 95% CI, 0.01 to 10.9), and extubation was performed within 7 days in 473 patients (97.7%) and 458 patients (94.4%), respectively (difference, 3.3 percentage points; 95% CI, 0.8 to 5.9). Reintubation was performed in 72 of 481 patients (14.9%) in the PSV group and in 65 of 477 patients (13.6%) in the T-piece group (difference, 1.3 percentage points; 95% CI, −3.1 to 5.8). Cardiac or respiratory arrest was a reason for reintubation in 9 patients (3 in the PSV group and 6 in the T-piece group).ConclusionsAmong patients who had a high risk of extubation failure, spontaneous-breathing trials performed with PSV did not result in significantly more ventilator-free days at day 28 than spontaneous-breathing trials performed with a T-piece. (Supported by the French Ministry of Health; TIP-EX ClinicalTrials.gov number, NCT04227639.)

Patient-Ventilator Synchrony in Neurally-Adjusted Ventilatory Assist and Variable Pressure Support Ventilation.

Neurally-adjusted ventilatory assist (NAVA) improves patient-ventilator synchrony and reduces the risk of respiratory over-assistance. Variable pressure support ventilation (PSV) is a recently introduced mode of assisted ventilation that has also shown reduction in patient-ventilator asynchronies. We hypothesized that NAVA would reduce patient-ventilator asynchronies and inspiratory effort compared to variable PSV because breathing variability was intrinsically determined by the patient and not by the ventilator. This study aimed to evaluate patient-ventilator asynchronies and inspiratory effort pressure-time product (PTP) between NAVA and variable PSV in subjects with mild ARDS. After 24 h of controlled mechanical ventilation, subjects (PaO2 /FIO2 200-300 and PEEP level < 10 cm H2O) were randomized in sequence 1:1 by using a web-based encrypted platform and assigned to NAVA or variable PSV groups. Both modes of ventilation were consecutively kept for 24 h unless there were clinical changes. The primary aim of this study was to evaluate differences in asynchrony index (AI) between variable PSV and NAVA. Our secondary aims were to evaluate the coefficient of variation (CV) of breathing patterns and inspiratory effort between the groups. Thirteen subjects were randomized in the NAVA group and 13 subjects in the variable PSV group. AI over time and minute PTP (PTPmin) were not different between NAVA and variable PSV groups (AI t0P = .52, AI t12P = .27, AI t24P = .12; and PTPmin-t0P = .60, PTPmin-t12P = .57, PTPmin-t24P = .85, respectively). CV for tidal volume (VT) and pressure support (PS) was lower in variable PSV group over time compared with NAVA group (P < .05). In this randomized controlled trial including subjects with mild ARDS, NAVA and variable PSV had comparable effects on patient-ventilator synchronies and PTP. However, variable PSV reduced the variability of VT and PS when compared with NAVA.

Neurally-Adjusted Ventilatory Assist Versus Pressure Support Ventilation During Noninvasive Ventilation.

Noninvasive ventilation (NIV) is increasingly used during ventilatory support. Neurally-adjusted ventilatory assist (NAVA) is a mode of mechanical ventilation that can improve patient-ventilator interaction. We conducted a meta-analysis to compare patient-ventilator interaction and clinical outcomes between NAVA and pressure support ventilation (PSV) in adult subjects during NIV. The PubMed, Cochrane Library, Web of Science, OpenGrey, and Embase databases were searched for appropriate clinical trials comparing NIV-NAVA with NIV-PSV for adult subjects. Comparisons of asynchrony index (AI), types of asynchrony, and clinical outcomes were pooled. Fifteen studies were included involving 615 subjects. AI was significantly lower in NAVA than PSV group (mean difference [MD] -14.70 [95% CI -23.20 to -6.19], P < .001). Subgroup analysis grouped by exacerbation of COPD or non-COPD showed that the AI of NAVA was lower than PSV in COPD exacerbation (MD -14.56 [95% CI -21.04 to -8.09], P < .001) and non-COPD (MD -3.02 [95% CI -4.44 to -1.61], P < .001). Severe asynchrony was significantly lower in NAVA than in PSV (odds ratio 0.06 [95% CI 0.03-0.11], P < .001). Inspiratory trigger delay in NAVA was significantly lower than PSV (MD -129.60 [95% CI -148.43 to -110.78], P < .001). NAVA had longer ICU length of stay than PSV (MD 1.22 [95% CI 0.44-2.00], P = .002). Level of discomfort was significantly higher in NAVA group than PSV group (MD 0.62 [95% CI 0.02-1.21], P = .040). NAVA has advantages in ventilator-patient interaction compared to PSV in NIV. Further research is needed in order to estimate effects on clinical outcomes.

Comparison between pressure support ventilation and T-piece in spontaneous breathing trials

BackgroundRecent guidelines recommended conducting spontaneous breathing trial (SBT) with modest inspiratory pressure augmentation rather than T-piece or continuous positive airway pressure. However, it was based on few studies focused on the outcomes of extubation rather than the weaning process, despite the existence of various weaning situations in clinical practice. This study was designed to investigate the effects of SBT with pressure support ventilation (PSV) or T-piece on weaning outcomes.MethodsAll consecutive patients admitted to two medical intensive care units (ICUs) and those requiring mechanical ventilation (MV) for more than 24 h from November 1, 2017 to September 30, 2020 were prospectively registered. T-piece trial was used until March 2019, and then, pressure support of 8 cmH2O and 0 positive end-expiratory pressure were used for SBT since July 2019, after a 3-month transition period for the revised SBT protocol. The primary outcome of this study was successful weaning defined according to the WIND (Weaning according to a New Definition) definition and were compared between the T-piece group and PSV group. The association between the SBT method and weaning outcome was evaluated with logistic regression analysis.ResultsIn this study, 787 eligible patients were divided into the T-piece (n = 473) and PSV (n = 314) groups after excluding patients for a 3-month transition period. Successful weaning was not different between the two groups (85.0% vs. 86.3%; p = 0.607). However, the PSV group had a higher proportion of short weaning (70.1% vs. 59.0%; p = 0.002) and lower proportion of difficult weaning (13.1% vs. 24.1%; p < 0.001) than the T-piece group. The proportion of prolonged weaning was similar between the two groups (16.9% vs. 16.9%; p = 0.990). After excluding patients who underwent tracheostomy before the SBTs, similar results were found. Reintubation rates at 48 h, 72 h, and 7 days following the planned extubation were not different between the PSV and T-piece groups. Moreover, no significant differences in intensive care unit and hospital mortality and length of stay were observed.ConclusionsIn critically ill medical patients, SBT using PSV was not associated with a higher rate of successful weaning compared with SBT using T-piece. However, PSV could shorten the weaning process without increasing the risk of reintubation.

Comparative Study between Automatic Tube Compensation (ATC) and Pressure Support Ventilation (PSV) as a Mode of Weaning from Mechanical Ventilation in Patients with Respiratory Failure

Abstract Background Weaning covers the entire process of liberating the patient from mechanical support and from the endotracheal tube (ETT). Weaning from mechanical ventilation (MV) is a challenge. Its prolongation is related to increased mortality. Aim of the Work is to assess the value of ATC in predicting successful weaning and hastening the weaning process. This study will compare the benefits and effects of ATC versus PSV as weaning modes on spontaneous breathing trials and work of breathing. Patients and Mehtods This prospective non randomized was done on 50 adult patients admitted to the Critical Care Medicine Department in Ain shams University Hospital presenting with ARF and mechanically ventilated for at least 24 hours. They were divided into two groups: Group I “ATC group” Each underwent a 1-hour spontaneous breathing trial, using ATC mode and Group II “PSV group” PSV mode was used. Results In the present study we have found that the use of ATC during a spontaneous breathing trial was as effective as PSV in predicting the ability of patients to maintain spontaneous, unassisted breathing for more than 48 hours after removal of the endotracheal tube. In our study, there was no significant difference in the number of patients who tolerated the spontaneous breathing trial and then extubated between ATC and PSV groups (60 % vs. 56% respectively, p &amp;gt; 0.05). Both modes had comparable sensitivity, and +ve predictive value. Sensitivity was 80.0% versus 75.0% and the positive predictive value was 88.0%, versus 87.0% for ATC versus PSV respectively. The specificity was comparable (76.8% versus 80.0 % in ATC versus PSV respectively). ATC group had higher negative predictive than PSV group (82.0% versus 70.1%, respectively). In our study, criteria for successful extubation were met in 56.0%. In ATC group 60.0% met the criteria for successful extubation vs. 60% in PSV group. In the present study it was found that male patients were the most predominant in both groups (72.0% in ATC group and 68% in PSV group). This is expected as cigarette smoking is prevalent among males and is the single most important and most prevalent risk factor for the development of COPD. In our study, about one third of patients had COPD exacerbation as a cause for ARF. Conclusion In ICU population, ATC was safe, reliable, and can be reasonably used for weaning trials. ATC confers a potential benefit in weaning duration, weaning category, number of Ss, failure of first SBT extubation outcome, ICU length of stay, complication, and mortality rate. In addition, ATC improves the predictive value of RR/TV and IWI in predicting weaning success.

Predictive efficacy of weaning index on mechanical ventilation evacuation.

The timely weaning of mechanical ventilation can shorten intensive care unit (ICU) stay times and reduce the complications related to mechanical ventilation. This study sought to investigate the predictive role of a weaning index (WI) on mechanical ventilation evacuation by measuring minute ventilation volume (MVV) across different ventilation modes. Patients suffering from respiratory failure for a variety of reasons were included in the study if they received mechanical ventilation for more than 48 hours in the ICU. The patients were randomly allocated to either the assist/control (A/C) group or the pressure support ventilation (PSV) group according to the ventilator mode. The factors associated with weaning success and failure were analyzed. A total of 40 patients participated in this study. Of these, 25 weaning cases were successful and 15 were failures. There were 19 cases in the A/C group, yielding a success rate of 63%, and 21 cases in the PSV group, yielding a success rate of 62%. There were no significant differences between the two groups in terms of age, gender, ideal weight, Acute Physiology and Chronic Health Evaluation (APACHE) II score, ICU stay time and hospitalization time. There were significant differences in the mechanical ventilation duration between the two groups (P<0.05). When the WI was less than 50.44, the sensitivity and specificity of predicting weaning success were 72% and 98%. The area under the receiver operating characteristic (ROC) curve was 0.928±0.03. When the WI of the A/C group was less than 61.45, the sensitivity and specificity of predicting weaning success were 98% and 72%, respectively. The area under the ROC curve was 0.917±0.068. When the WI of the PSV group was less than 51.45, the sensitivity and specificity of predicting weaning success were 74.6% and 100%, respectively. The area under the ROC curve was 0.933±0.046. Compared with RSBI, WI shows a better value in predicting weaning, especially for mechanically ventilated patients in PSV mode, WI has greater value in predicting weaning.

Spontaneous Breathing Trial with Pressure Support-Ventilation versus “T-Tube” for Head Trauma Patient: A Randomized Controlled Clinical Trial

Background: Assessing patients’ readiness for weaning through spontaneous breathing trial (SBT) is a reliable method for improving weaning and extubation outcomes. Until now, there are controversies over the best SBT method. Objective: This study aimed to compare the clinical outcomes of the T-piece and pressure support ventilation (PSV) SBT methods among patients with traumatic brain injury. Methods: In this randomized controlled trial, 72 patients under mechanical ventilation were purposively recruited from the intensive care unit of Shahid Rajaei hospital, Qazvin, Iran, and randomly allocated to an intervention and a control group. SBT was conducted in the intervention and control groups through the T-piece and PSV (with pressure support of less than 8 cm H2O), respectively. The groups were compared with each other respecting weaning outcomes, extubation success, length of mechanical ventilation, length of hospital stay, and mortality rate. Data were compared using the Chi-square and the independent-sample t-tests. Results: Weaning success rate in the T-piece group was significantly greater than the PSV group (P=0.024), while the post-weaning length of hospital stay in the T-piece group was significantly shorter than the PSV group (P=0.05). There were no significant differences in respecting extubation success rate and length of mechanical ventilation between the groups (P>0.05). Conclusion: The T-piece method for SBT could be better tolerated by patients with traumatic brain injury compared with PSV.

Effect of different mechanical ventilation modes on patient-ventilator synchrony and diaphragm function in rabbit model of acute respiratory distress syndrome

Objective: To observe the effect of different modes of mechanical ventilation on patient-ventilator synchrony and diaphragm function in rabbits with acute respiratory distress syndrome(ARDS). Methods: Eighteen New Zealand rabbit models of ARDS were induced by intratracheal infusion hydrochloric acid until the oxygenation index (PaO(2)/FiO(2)) was less than 200 mmHg, and then divided into three groups with random number: assisted-controlled mechanical ventilation (A/C) group, pressure support ventilation (PSV) group and neurally adjusted ventilatory assist (NAVA) group. All of them were ventilated for four hours with the targeted tidal volume (V(T)) (6 ml/kg) and the positive end-expiratory pressure (PEEP) titrated with the maximum oxygenation method. Gas exchange, pulmonary mechanics and patient-ventilator synchrony were determined during 4 h of ventilation and the concentrations of malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione (GSH) in diaphragm were measured after 4 h of ventilation. The q test was used for the multiple comparison of the sample mean. Results: There were no significant differences in PaO(2)/FiO(2) between three groups during ventilation 1-4 h (F=1.029, P>0.05). The V(T) in NAVA group was obviously lower than that in PSV group and the respiratory rate (RR) and the electrical activity of diaphragm(EAdi) were higher than those in A/C group(all P<0.05).The trigger delay and off cycle delay the in NAVA group were markedly lower than those in A/C and PSV group during ventilation 1-4 h(F=14.312, 9.342, both P<0.05). Asynchrony index in NAVA group (3.1%±1.0%) was obviously lower than those in A/C group (22.3%±5.2%) and PSV group(8.4%±2.3%) (F=7.192, P<0.05). In NAVA group, peak EAdi (EAdi(peak)) and peak airway pressure (Ppeak) were markedly correlated (r=0.97±0.16, P<0.05), while Ppeak delivery in A/C and PSV group was not correlated to EAdi(peak) (r=0.38±0.13,0.46±0.15, both P>0.05).Compared with A/C group, the concentration of MDA in the diaphragm in NAVA group was obviously lower(P<0.05). SOD and GSH level inthe diaphragm in NAVA group were both obviously higher than those in A/C group (both P<0.05). Conclusions: It is helpful to avoid eccentric contraction of diaphragm, lessen oxidative stress and alleviate ventilator-related diaphragm dysfunction by keeping spontaneous breathing as far as possible and subject-ventilator synchrony when ventilation in ARDS with NAVA.

Neurally Adjusted Ventilatory Assist in Difficult Weaning: Promising Findings on a Prickly Issue.

Neurally Adjusted Ventilatory Assist in Difficult Weaning: Promising Findings on a Prickly Issue.

Neurally adjusted ventilatory assist versus pressure support ventilation: a randomized controlled feasibility trial performed in patients at risk of prolonged mechanical ventilation

BackgroundThe clinical effectiveness of neurally adjusted ventilatory assist (NAVA) has yet to be demonstrated, and preliminary studies are required. The study aim was to assess the feasibility of a randomized controlled trial (RCT) of NAVA versus pressure support ventilation (PSV) in critically ill adults at risk of prolonged mechanical ventilation (MV).MethodsAn open-label, parallel, feasibility RCT (n = 78) in four ICUs of one university-affiliated hospital. The primary outcome was mode adherence (percentage of time adherent to assigned mode), and protocol compliance (binary—≥ 65% mode adherence). Secondary exploratory outcomes included ventilator-free days (VFDs), sedation, and mortality.ResultsIn the 72 participants who commenced weaning, median (95% CI) mode adherence was 83.1% (64.0–97.1%) and 100% (100–100%), and protocol compliance was 66.7% (50.3–80.0%) and 100% (89.0–100.0%) in the NAVA and PSV groups respectively. Secondary outcomes indicated more VFDs to D28 (median difference 3.0 days, 95% CI 0.0–11.0; p = 0.04) and fewer in-hospital deaths (relative risk 0.5, 95% CI 0.2–0.9; p = 0.032) for NAVA. Although overall sedation was similar, Richmond Agitation and Sedation Scale (RASS) scores were closer to zero in NAVA compared to PSV (p = 0.020). No significant differences were observed in duration of MV, ICU or hospital stay, or ICU, D28, and D90 mortality.ConclusionsThis feasibility trial demonstrated good adherence to assigned ventilation mode and the ability to meet a priori protocol compliance criteria. Exploratory outcomes suggest some clinical benefit for NAVA compared to PSV. Clinical effectiveness trials of NAVA are potentially feasible and warranted.Trial registrationClinicalTrials.gov, NCT01826890. Registered 9 April 2013.

High-Flow Oxygen Therapy to Speed Weaning From Mechanical Ventilation: A Prospective Randomized Study.

High-flow oxygen therapy has been widely adopted, but its use for weaning patients from mechanical ventilation has not been reported. To evaluate whether high-flow oxygen therapy improves the efficiency of weaning patients from mechanical ventilation. In a single-center, prospective study, patients receiving mechanical ventilation were randomly assigned to 1 of 3 groups (T-tube, pressure support ventilation, or high-flow oxygen) during 2-hour spontaneous breathing trials in a 14-day study. Participants were followed up until hospital discharge or death. Of 268 patients included, 90 were assigned to the T-tube group, 96 to the pressure support ventilation group, and 82 to the high-flow oxygen group. The first-day 2-hour spontaneous breathing trial passing rates were higher in the pressure support ventilation and high-flow oxygen groups than in the T-tube group (P < .05). The time needed to pass the spontaneous breathing trial was less in the pressure support ventilation and high-flow oxygen groups than in the T-tube group (P < .05). The reintubation rate was lower and the successful weaning rate on the first day was higher in the high-flow oxygen group than in the T-tube and pressure support ventilation groups (P < .05). During the 14-day study period, the weaning time was less in the high-flow oxygen group than in the T-tube and pressure support ventilation groups (P < .05). High-flow oxygen therapy can reduce the time needed to wean patients from mechanical ventilation by shortening the time needed to pass a spontaneous breathing trial and by decreasing the reintubation rate.

Assessment of Some Predictors of Weaning from Mechanical Ventilation in Acutely Intoxicated Patients Admitted to the Poison Control Center-Ain Shams University

Background: Respiratory failure is a common complication of poisoning with significant morbidity and mortality. Mechanical ventilation is life saving. Weaning is the process of liberating patient from mechanical ventilatory support. Interleukin-6 (IL-6) and C-reactive protein (CRP) are inflammatory mediators, released in response to many stressful conditions as weaning from mechanical ventilation. Aim of the work: The aim of the study was to assess the role of serum (IL6) level and (CRP) as predictors of outcome of weaning from mechanical ventilation in acutely intoxicated patients admitted to the Poison Control Center– Ain Shams University Hospitals (PCC-ASUHs). And to assess their role in selection of the most appropriate mode for weaning by comparing weaning by pressure support ventilation (PSV) mode, synchronized intermittent mandatory ventilation (SIMV) mode and weaning by the once-daily trial of spontaneous breathing trial by using (T-piece). Patients and Methods: The study included 58 acutely intoxicated patients, intubated and mechanically ventilated, admitted to the Intensive Care Unit (ICU) of PCC-ASUHs during the period from May 2016 till September 2018. Patients were categorized consecutively according to the outcome of the 2-hour of spontaneous breathing trial (SBT) into 2 groups: Group I (The SBT Success group): included 19 patients who succeed spontaneous breathing trial. Group II (The SBT failed group): included 39 patients who failed SBT which was further subdivided into 3 groups according to the method of weaning: group (1) PSV group, group (2) SIMV group and group (3) Once T-piece group, each group including 13 patients. Results: IL-6 was significantly increased after 2 days in patients who failed the SBT compared to the success group, while CRP was significantly higher in the failed group during weaning trial and 2 days after. There is no significant difference between the three weaning modes regarding IL6 and CRP. Conclusion: Patients who failed the SBT presented higher inflammatory parameters than those who passed. CRP could predict the outcome of weaning from mechanical ventilation.

Effect of Pressure Support vs T-Piece Ventilation Strategies During Spontaneous Breathing Trials on Successful Extubation Among Patients Receiving Mechanical Ventilation

Daily spontaneous breathing trials (SBTs) are the best approach to determine whether patients are ready for disconnection from mechanical ventilation, but mode and duration of SBT remain controversial. To evaluate the effect of an SBT consisting of 30 minutes of pressure support ventilation (an approach that is less demanding for patients) vs an SBT consisting of 2 hours of T-piece ventilation (an approach that is more demanding for patients) on rates of successful extubation. Randomized clinical trial conducted from January 2016 to April 2017 among 1153 adults deemed ready for weaning after at least 24 hours of mechanical ventilation at 18 intensive care units in Spain. Follow-up ended in July 2017. Patients were randomized to undergo a 2-hour T-piece SBT (n = 578) or a 30-minute SBT with 8-cm H2O pressure support ventilation (n = 557). The primary outcome was successful extubation (remaining free of mechanical ventilation 72 hours after first SBT). Secondary outcomes were reintubation among patients extubated after SBT; intensive care unit and hospital lengths of stay; and hospital and 90-day mortality. Among 1153 patients who were randomized (mean age, 62.2 [SD, 15.7] years; 428 [37.1%] women), 1018 (88.3%) completed the trial. Successful extubation occurred in 473 patients (82.3%) in the pressure support ventilation group and 428 patients (74.0%) in the T-piece group (difference, 8.2%; 95% CI, 3.4%-13.0%; P = .001). Among secondary outcomes, for the pressure support ventilation group vs the T-piece group, respectively, reintubation was 11.1% vs 11.9% (difference, -0.8%; 95% CI, -4.8% to 3.1%; P = .63), median intensive care unit length of stay was 9 days vs 10 days (mean difference, -0.3 days; 95% CI, -1.7 to 1.1 days; P = .69), median hospital length of stay was 24 days vs 24 days (mean difference, 1.3 days; 95% CI, -2.2 to 4.9 days; P = .45), hospital mortality was 10.4% vs 14.9% (difference, -4.4%; 95% CI, -8.3% to -0.6%; P = .02), and 90-day mortality was 13.2% vs 17.3% (difference, -4.1% [95% CI, -8.2% to 0.01%; P = .04]; hazard ratio, 0.74 [95% CI, 0.55-0.99]). Among patients receiving mechanical ventilation, a spontaneous breathing trial consisting of 30 minutes of pressure support ventilation, compared with 2 hours of T-piece ventilation, led to significantly higher rates of successful extubation. These findings support the use of a shorter, less demanding ventilation strategy for spontaneous breathing trials. ClinicalTrials.gov Identifier: NCT02620358.

Pressure-support ventilation or T-piece spontaneous breathing trials for patients with chronic obstructive pulmonary disease - A randomized controlled trial.

BackgroundLittle is known about the best strategy for weaning patients with chronic obstructive pulmonary disease (COPD) from mechanical ventilation. Spontaneous breathing trials (SBT) using a T-piece or pressure-support ventilation (PSV) have a central role in this process. Our aim was to compare T-piece and PSV SBTs according to the duration of mechanical ventilation (MV) in patients with COPD.MethodsPatients with COPD who had at least 48 hours of invasive MV support were randomized to 30 minutes of T-piece or PSV at 10 cm H2O after being considered able to undergo a SBT. All patients were preemptively connected to non-invasive ventilation after extubation. Tracheostomized patients were excluded. The primary outcome was total invasive MV duration. Time to liberation from MV was assessed as secondary outcome.ResultsBetween 2012 and 2016, 190 patients were randomized to T-piece (99) or PSV (91) groups. Extubation at first SBT was achieved in 78% of patients. The mean total MV duration was 10.82 ± 9.1 days for the T-piece group and 7.31 ± 4.9 days for the PSV group (p < 0.001); however, the pre-SBT duration also differed (7.35 ± 3.9 and 5.84 ± 3.3, respectively; p = 0.002). The time to liberation was 8.36 ± 11.04 days for the T-piece group and 4.06 ± 4.94 for the PSV group (univariate mean ratio = 2.06 [1.29–3.27], p = 0.003) for the subgroup of patients with difficult or prolonged weaning. The study group was independently associated with the time to liberation in this subgroup.ConclusionsThe SBT technique did not influence MV duration for patients with COPD. For the difficult/prolonged weaning subgroup, the T-piece may be associated with a longer time to liberation, although this should be clarified by further studies.Trial registrationClinicalTrials.gov NCT01464567, at November 3, 2011.

Effects of pressure support ventilation on ventilator-induced lung injury in mild acute respiratory distress syndrome depend on level of positive end-expiratory pressure: A randomised animal study.

Harmful effects of spontaneous breathing have been shown in experimental severe acute respiratory distress syndrome (ARDS). However, in the clinical setting, spontaneous respiration has been indicated only in mild ARDS. To date, no study has compared the effects of spontaneous assisted breathing with those of fully controlled mechanical ventilation at different levels of positive end-expiratory pressure (PEEP) on lung injury in ARDS. To compare the effects of assisted pressure support ventilation (PSV) with pressure-controlled ventilation (PCV) on lung function, histology and biological markers at two different PEEP levels in mild ARDS in rats. Randomised controlled experimental study. Basic science laboratory. Thirty-five Wistar rats (weight ± SD, 310 ± 19) g received Escherichia coli lipopolysaccharide (LPS) intratracheally. After 24 h, the animals were anaesthetised and randomly allocated to either PCV (n=14) or PSV (n=14) groups. Each group was further assigned to PEEP = 2 cmH2O or PEEP = 5 cmH2O. Tidal volume was kept constant (≈6 ml kg). Additional nonventilated animals (n=7) were used as a control for postmortem analysis. Ventilatory and mechanical parameters, arterial blood gases, diffuse alveolar damage score, epithelial integrity measured by E-cadherin tissue expression, and biological markers associated with inflammation (IL-6 and cytokine-induced neutrophil chemoattractant, CINC-1) and type II epithelial cell damage (surfactant protein-B) were evaluated. In both PCV and PSV, peak transpulmonary pressure was lower, whereas E-cadherin tissue expression, which is related to epithelial integrity, was higher at PEEP = 5 cmH2O than at PEEP = 2 cmH2O. In PSV, PEEP = 5 cmH2O compared with PEEP = 2 cmH2O was associated with significantly reduced diffuse alveolar damage score [median (interquartile range), 11 (8.5 to 13.5) vs. 23 (19 to 26), P = 0.005] and expressions of IL-6 and CINC-1 (P = 0.02 for both), whereas surfactant protein-B mRNA expression increased (P = 0.03). These changes suggested less type II epithelial cell damage at a PEEP of 5 cmH2O. Peak transpulmonary pressure correlated positively with IL-6 [Spearman's rho (ρ) = 0.62, P = 0.0007] and CINC-1 expressions (ρ = 0.50, P = 0.01) and negatively with E-cadherin expression (ρ = -0.67, P = 0.0002). During PSV, PEEP of 5 cmH2O, but not a PEEP of 2 cmH2O, reduced lung damage and inflammatory markers while maintaining epithelial cell integrity.