Automatic Tube Compensation Research Articles

Assessment of Knowledge and Practices of Nursing Personnel While Caring of Brain Dead Patients Potential for Organ Donation

Introduction Organ donation and transplantation is a life-saving procedure for patients with end-stage organ failure, but it depends on the availability of donor organs. Nurses play a major role to provide care to brain-dead patient potential for organ donation and efficient care to increase the organ’s survival. For years many efforts have been made to create awareness in public regarding organ donation but donors are still very less than demand. Most of the recipients are waiting for organs for more than 6–8 years and many died because of the paucity of donors. Hence, knowledge of nursing personnel is extremely important to the success of organ donation. Objective To assess the knowledge and practices of nursing personnel while caring of brain-dead patients potential for organ donation. Methodology A descriptive research design was adopted to carry out the study. The study was conducted among 30 nursing personnel caring for brain-dead patients from the automatic tube compensation ICU and various units of Nehru Hospital, PGIMER, Chandigarh. Nurses were given questionnaires to fill, including a sociodemographic data sheet and a knowledge questionnaire. The practices of caring for brain-dead patients were observed by using an observation checklist, and a total of 30 observations were made. Results The findings of the study revealed that 50% of nursing personnel had good knowledge about the care of brain-dead patients, 32% had average knowledge, whereas 18% had poor knowledge. There were 42 steps/items of practice regarding care of a brain dead patient. Around one third (38%) of the steps were followed by the participants, some of them followed 57% of the steps. Conclusion Only half of the nursing personnel were possessing good knowledge about the care of brain-dead patients and less than half were doing good practices about the care of brain-dead patients; hence, there is a need to educate the nursing personnel regarding caring of brain-dead patients.

Activation of Automatic Tube Compensation Mode Attenuates Auto-PEEP in Chronic Obstructive Pulmonary Disease Patients.

Dynamic hyperinflation in chronic obstructive pulmonary disease (COPD) results in intrinsic positive end-expiratory pressure (auto-PEEP). Automatic tube compensation (ATC) is used to increase airway pressure in COPD and overcome endotracheal tube (ETT)-imposed respiratory workload. We aim to investigate effects of ATC activation on auto-PEEP decrease in COPD. ATC was activated three times a day (1 min duration) in the morning, evening, and night shift. Auto-PEEP was measured for the 1 min period (every 6 s) following ATC activation. Linear mixed model (LMM) was used to measure changes in auto-PEEP and compare with baseline value. Age, gender, and COPD types were inserted in model as covariates and analyzed using SPSS. A total of 60 patients including COPD (n = 40) and COPD with exacerbation (n = 20) were included. Compared with exacerbated COPD, baseline auto-PEEP in COPD was significantly lower in morning (p = 0.011), evening (p = 0.043), and night shift (p = 0.007). After ATC activation, auto-PEEP decreased significantly in COPD in morning, evening, and night (p = 0.001), but magnitude of this decrease was notably larger in COPD than in exacerbated COPD (p = 0.001). Moreover, there was a significant relationship between COPD exacerbation and changes in auto-PEEP in morning (β = -0.27, p = 0.001), evening (β = -0.16, p = 0.001), and night (β = -0.26, p = 0.001). The activation of ATC mode in COPD patients under mechanical ventilation could decrease the value of auto-PEEP. Nevertheless, COPD patients with an exacerbation appear to benefit less from ATC activation.

The influence of different spontaneous breathing trials on regional ventilation distribution in patients with prolonged mechanical ventilation

ObjectiveThis study aimed to explore the influence of different spontaneous breathing trials (SBTs) on regional ventilation distribution in patients with prolonged mechanical ventilation (PMV). MethodsA total of 24 patients with PMV were analyzed retrospectively. They received three different SBT modes which are automatic tube compensation (ATC), continuous positive airway pressure (CPAP), and T-piece (TP), over three days, and every SBT lasted two hours. Electrical impedance tomography (EIT) was used to monitor the SBT process and five-minute EIT data from five periods (pre-SBT which is t0, at the beginning and the end of the first hour SBT are t1 and t2, at the beginning and the end of the second hour SBT are t3 and t4) were analyzed. ResultsIn all PMV patients, the temporal skew of aeration (TSA) values at t3 were significantly different in three SBTs (ATC: 18.18±22.97; CPAP: 20.42±17.01; TP:11.26±11.79; p=0.05). In the weaning success group, TSA (t1) values were significantly different too (ATC: 11.11±13.88; CPAP: 19.09±15.77; TP: 9.09±12.74; p=0.04). In the weaning failure group, TSA (t4) values were significantly different in three SBTs (ATC: 36.67±18.46; CPAP: 15.38±11.69; TP: 17.65±17.93; p=0.04). The patient’s inspiratory effort (Global flow index at t1) in patients with weaning failure under CPAP (3.51±4.31) was significantly higher than that in the ATC (1.15±1.47) and TP (0.89±1.28). The SBT mode with the best ventilation uniformity may be the one that activates the respiratory muscles the most which may be the optimal SBT. The SBT mode of most uniform ventilation distribution settings varies from patient to patient. ConclusionThe regional ventilation distribution was different for each individual, making the SBT with the best ventilation distribution of patients need to be personalized. EIT is a tool that can be considered for real-time assessment.

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.

Automatic tube compensation for liberation from prolonged mechanical ventilation in tracheostomized patients: A retrospective analysis

To analyze the predictability of an automatic tube compensation (ATC) screening test compared with the conventional direct liberation test performed before continuous oxygen support for MV liberation. This retrospective study analyzed tracheostomized patients with prolonged MV in a weaning unit of a medical center in Taiwan. In March 2020, a four-day ATC test to screen patient eligibility for ventilator liberation was implemented, intended to replace the direct liberation test. We compared the predictive accuracy of these two screening methods on the relevant outcomes in the two years before and one year after the implementation of this policy. Of the 403 cases, 246 (61%) and 157 (39%) received direct liberation and ATC screening tests, respectively. These two groups had similar outcomes: successful weaning upon leaving the Respiratory Care Center (RCC), success on day 100 of MV, success at hospital discharge, and in-hospital survival. Receiver operating characteristic curve analysis showed that the ATC screening test had better predictive ability than the direct liberation test for RCC weaning, discharge weaning, 100-day weaning, and in-hospital survival. This closed-circuit ATC screening test before ventilator liberation is a feasible and valuable method for screening PMV patients undergoing ventilator liberation in the pandemic era. Its predictability for a comparison with the open-circuit oxygen test requires further investigation.

Automatic Tube Compensation During Spontaneous Breathing Trials.

Automatic tube compensation (ATC) is an option available in any ICU ventilator that compensates for the resistive pressure drop due to the endotracheal tube. The goal of the present study was to compare ATC to other patient triggered modes of support in terms of spontaneous breathing trial (SBT) and extubation success. Two authors (JB and PCF), independently and blinded to each other, searched through PubMed, Web of Science, and Cochrane from inception-May 26, 2021, with the following search terms entered as MeSH terms in all fields: "Automatic Tube Compensation." randomized studies that included subjects > 16 y old undergoing an SBT. crossover studies, pediatric studies, animal studies, or experimental studies on test lungs or on computer simulation; other languages than French, Spanish, or English; studies not published in a full-text format (eg, abstract or letter); and reviews. A frequentist network meta-analysis was conducted with the aim to investigate the effectiveness of ATC on SBT and extubation outcomes. SBT was defined as successful if patients could tolerate the SBT based on predetermined criteria, whether it was followed by extubation. Successful extubation was defined as the absence of re-intubation, noninvasive ventilation, or signs of respiratory distress within the 48 h after extubation. The pooled analyses used random-effect models, and the effect size was expressed as relative risk or mean difference for categorical and continuous variables, respectively. P-scores were used to rank all treatments and to identify the intervention with the highest probability of being the best. Of the 234 retrieved papers, 7 met the inclusion criteria. In terms of SBT success, ATC100+PEEP < 7.5 and PS10+PEEP < 7.5 were superior to T-piece. Likewise, PS10+PEEP < 7.5 was the intervention with the highest probability of being the best (P-score: 0.90). In terms of extubation success, ATC100+PEEP < 7.5 cm H2O was significantly better than PEEP < 7.5 and T-piece. Likewise, it had the highest probability of being the best (P-score= 0.90). ATC is the modality with the highest probability of extubation success but not in terms of SBT success.

Comparison of ultrasound assessment for diaphragmatic workload during spontaneous breathing trial between automatic tube compensation and pressure support ventilation: Study protocol

Background: The process of weaning from mechanical ventilation is crucial. Less demanding spontaneous breathing trials (SBT) can be done by either automatic tube compensation (ATC) or pressure support ventilation (PSV) to decrease inspiratory effort by endotracheal tube resistance compensation. This study aimed to assess the patient’s effort, by diaphragm ultrasonography with ATC compared to PSV during SBT. Methods: Patients who have been on mechanical ventilation for more than 48 hours and meet the weaning requirements are given 30 minutes for ATC and 30 minutes for PSV in this randomized control experiment. The diaphragm workload difference, as assessed by diaphragm thickness fraction, was the primary outcome. The sensitivity and specificity of ultrasound-measured diaphragmatic muscle activity measures in predicting ventilator weaning and effective extubation were secondary outcomes. Hypothesis: Intubated patients should be (1) weaning with lower effort SBT mode (2) predicted weaning success with more accurately parameters Ethics and dissemination: Ramathibodi Human Research Ethics Committee has approved the trial. The findings plan to summitted in peer-reviewed publications and conferences in critical care medicine or anesthesiology. Trial registration number: TCTR20210317004

Comparative Efficacy and Safety of Four Different Spontaneous Breathing Trials for Weaning From Mechanical Ventilation: A Systematic Review and Network Meta-Analysis

Background: Spontaneous breathing trial (SBT) has been used to predict the optimal time of weaning from ventilator. However, it remains controversial which trial should be preferentially selected. We aimed to compare and rank four common SBT modes including automatic tube compensation (ATC), pressure support ventilation (PSV), continuous positive airway pressure (CPAP), and T-piece among critically ill patients receiving mechanical ventilation (MV).Methods: We searched PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials (CENTRAL) to identify studies that investigated the comparative efficacy and safety of at least two SBT strategies among critically ill patients up to May 17, 2020. We estimated the surface under the cumulative ranking curve (SUCRA) to rank SBT techniques, and determined the certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation method. Primary outcome was weaning success. Secondary outcomes were reintubation, SBT success, duration of acute care, and intensive care unit (ICU) mortality. Statistical analysis was conducted by using RevMan 5.4, Stata, and R software.Results: We enrolled 24 trials finally. Extubation success rate was significantly higher in ATC than that in T-piece (OR, 0.28; 95% CI, 0.13–0.64) or PSV (OR, 0.53; 95% CI, 0.32–0.88). For SBT success, ATC was better than other SBT techniques, with a pooled OR ranging from 0.17 to 0.42. For reintubation rate, CPAP was worse than T-piece (OR, 2.76; 95% CI, 1.08 to 7.06). No significant difference was detected between SBT modes for the length of stay in ICU or long-term weaning unit (LWU). Similar result was also found for ICU mortality between PSV and T-piece. Majority direct results were confirmed by network meta-analysis. Besides, ATC ranks at the first, first, and fourth place with a SUCRA of 91.7, 99.7, and 39.9%, respectively in increasing weaning success and SBT success and in prolonging ICU or LWU length of stay among four SBT strategies. The confidences in evidences were rated as low for most comparisons.Conclusion: ATC seems to be the optimal choice of predicting successful weaning from ventilator among critically ill patients. However, randomized controlled trials (RCTs) with high quality are needed to further establish these findings.

Methods of Weaning From Mechanical Ventilation in Adult: A Network Meta-Analysis.

Background/Objective: The aim of study is to assess the efficacy of each ventilator weaning method for ventilated patients in intensive care units (ICUs).Methods: A systematic search was conducted using PubMed, Embase, and China National Knowledge Infrastructure to identify randomized control studies on ventilated patients regarding extubation associated outcomes (weaning success or failure, proportion requiring re-intubation, or mortality) from inception until April 01, 2020. Commonly used ventilation modes involved pressure support ventilation, synchronized intermittent mandatory ventilation, automatic tube compensation, continuous positive airway pressure, adaptive support ventilation, neurally adjusted ventilatory assist, proportional assisted ventilation, and SmartCare. Pooled estimates regarding extubation associated outcomes were calculated using network meta-analysis.Results: Thirty-nine randomized controlled trials including 5,953 patients met inclusion criteria. SmartCare and proportional assist ventilation were found to be effective methods in increasing weaning success (odds ratio, 2.72, 95% confidence interval (CI), 1.33–5.58, P-score: 0.84; odds ratio, 2.56, 95% CI, 1.60–4.11, P-score: 0.83; respectively). Besides, proportional assist ventilation had superior in reducing proportion requiring re-intubation rate (odds ratio, 0.48, 95% CI, 0.25–0.92, P-score: 0.89) and mortality (odds ratio, 0.48, 95% CI, 0.26–0.92, P-score: 0.91) than others.Conclusion: In general consideration, our study provided evidence that weaning with proportional assist ventilation has a high probability of being the most effective ventilation mode for patients with mechanical ventilation regarding a higher rate of weaning success, a lower proportion requiring reintubation, and a lower mortality rate than other ventilation modes.

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.

A Comprehensive Bench Assessment of Automatic Tube Compensation in ICU Ventilators for Better Clinical Management.

Automatic tube compensation (ATC) unloads endotracheal tube (ETT) resistance. We conducted a bench assessment of ATC functionality in ICU ventilators to improve clinical management. This study had 2 phases. First, we performed an international survey on the use of ATC in clinical practice, hypothesizing a rate of ATC use of 25%. Second, we tested 7 modern ICU ventilators in a lung model mimicking a normal subject (Normal), a subject with ARDS, and a subject with COPD. Inspiratory effort consisted of esophageal pressure over 30 consecutive breaths obtained in a real patient under weaning. A brand new 8-mm inner diameter ETT was attached to the lung model, and ATC was set at 100% compensation for the ETT. The 30 breaths were first run with ATC off and no ETT (ie, reference period), and then with ATC on and ETT (ie, active period). The primary end point was the difference in tidal volume (VT) between reference and active periods. We hypothesized that the VT difference should be equal to 0 in an ideally functioning ATC. VT difference was compared across ventilators and respiratory mechanics conditions using a linear mixed-effects model. The clinical use of ATC was 64% according to 644 individuals who responded to the international survey. The VT difference varied significantly across ventilators in all respiratory mechanics configurations. The divergence between VT difference and 0 was small but significant: the extreme median (interquartile range) values were -0.013 L (-0.019 to -0.002) in the COPD model and 0.056 L (0.051-0.06) in the Normal model. VT difference for all ventilators was 0.015 L (95% CI 0.013-0.018) in the ARDS model, which was significantly different from 0.021 L (95% CI 0.018-0.024) in the Normal model (P < .001) and 0.010 L (0.007-0.012) in the COPD model (P = .003). ATC is used more frequently in clinical practice than expected. In addition, VT delivery by ATC differed slightly though significantly between ventilators.

Role of Automatic Tube Compensation as Spontaneous Breathing Trial in Critically Ill Patients: A Systematic Review and Meta-Analysis

Objectives: The role of automatic tube compensation (ATC) compared to other spontaneous breathing trials (SBTs) in critically ill receiving mechanical ventilation remains uncertain. The aim of this meta-analysis was to determine the role of ATC in critically ill patients compared to alternative SBT techniques. Methods: We searched PubMed, Cochrane Library, and Embase to capture all potential randomized controlled trials (RCTs) investigating the comparative efficacy of ATC related to other SBT techniques including pressure support (PS), T-piece, continuous positive airway pressure (CPAP) from their inception to February 2020. Primary outcomes were successful extubation rate. Duration of weaning, intensive care unit (ICU) stay, hospital stay, and hospital mortality was regarded as secondary outcomes. We used a risk ratio with accompanying 95% confidence interval (CI) to express estimates. Reviewer Manager (RevMan) 5.1.0 was used to complete all statistical analyses. Results: We included 13 studies enrolling 1117 patients in the final analysis. Pooled results indicated no significant difference when ATC plus CPAP (ATC/CAPA) compared to PS (6 RCTs; 572 patients; risk ratio [RR], 1.15; 95% confidence interval [CI], 1.00 to 1.31), ATC versus T-piece (2 RCTs; 157 patients; RR, 1.14; 95% CI, 0.93 to 1.40), ATC plus PS (ATC/PS) versus PS alone (1 RCTs; 100 patients; RR, 1.15; 95% CI, 0.98 to 1.35), ATC/CPAP versus CPAP alone (3 RCTs; 247 patients; RR, 1.12; 95% CI, 0.97 to 1.29) in terms of successful extubation. Additionally, ATC was also not superior to PS, T-piece, or CPAP in improving the rate of reintubation, the duration of weaning, ICU stay, hospital stay, and hospital mortality. Conclusions: Compared to alternative SBT techniques including PSV and T-piece, ATC may have comparable predictive power of successful extubation in critically ill patients. However, a definite conclusion on this topic can not be drawn due to limited data. Therefore, further studies were required to establish our findings due to limited number of eligible studies and small accumulated sample size.

Low-pressure support vs automatic tube compensation during spontaneous breathing trial for weaning

BackgroundDuring spontaneous breathing trial, low-pressure support is thought to compensate for endotracheal tube resistance, but it actually should provide overassistance. Automatic tube compensation is an option available in the ventilator to compensate for flow-resistance of endotracheal tube. Its effects on patient effort have been poorly investigated. We aimed to compare the effects of low-pressure support and automatic tube compensation during spontaneous breathing trial on breathing power and lung ventilation distribution.ResultsWe performed a randomized crossover study in 20 patients ready to wean. Each patient received both methods for 30 min separated by baseline ventilation: pressure support 0 cmH2O and automatic tube compensation 100% in one period and pressure support 7 cmH2O without automatic tube compensation in the other period, a 4 cmH2O positive end-expiratory pressure being applied in each. Same ventilator brand (Evita XL, Draeger, Germany) was used. Breathing power was assessed from Campbell diagram with esophageal pressure, airway pressure, flow and volume recorded by a data logger. Lung ventilation distribution was assessed by using electrical impedance tomography (Pulmovista, Draeger, Germany). During the last 2 min of low-pressure support and automatic compensation period breathing power and lung ventilation distribution were measured on each breath. Breathing power generated by the patient’s respiratory muscles was 7.2 (4.4–9.6) and 9.7 (5.7–21.9) J/min in low-pressure support and automatic tube compensation periods, respectively (P = 0.011). Lung ventilation distribution was not different between the two methods.ConclusionsWe found that ATC was associated with higher breathing power than low PS during SBT without altering the distribution of lung ventilation.

ВЛИЯНИЕ РЕЖИМА КОМПЕНСАЦИИ СОПРОТИВЛЕНИЯ ДЫХАТЕЛЬНЫХ ПУТЕЙ НА ПОТРЕБЛЕНИЕ КИСЛОРОДА У ПАЦИЕНТОВ В ОТДЕЛЕНИИ ИНТЕНСИВНОЙ ТЕРАПИИ

In the mechanically ventilated patient, the single greatest cause of imposed work of breathing (WOB) is the resistance caused by the endotracheal tube (ETT). However, a special mode of ventilatory support called automatic tube compensation (ATC) delivers exactly the amount of pressure necessary to overcome the resistive load imposed by the ETT for the flow measured at the time (so-called variable pressure support). Materials and methods: 21 patients were included in our study who were on mechanical ventilation CPAP/PSV with tracheostomy tube of 8.0 mm. Pulse, BP, SpO 2 , Ppeak, PS, PEEP, FiO , VO 2 , VCO 2 , EE, RQ, RSBI were monitored. 100% ARC compensation was given. Duration of observation was 60 minutes for each patient. Observation study was 2 stopped if patients’ condition deteriorated. Results: it was observed that mean BR before ARC was 20.3 ± 4.6 & mean BR after ARC was 20.8 ± 5.4, mean VO 2 before ARC was 238 ± 72.5 & mean VO 2 after ARC was 235.6 ± 70.7, in addition to that we observed that there was a rise in Ppeak of about 3 mm water column. Conclusion: ATC mode did not reduce the work of breathing as all the other measured parameters such as pulse, BR, RSBI, VO 2 , VCO 2 didn’t have a significant change.

Work of breathing for cuffed and uncuffed pediatric endotracheal tubes in an invitro lung model setting.

Over the last decade, cuffed endotracheal tubes are increasingly used in pediatric anesthesia and also in pediatric intensive care. However, the smaller inner diameter of cuffed endotracheal tubes and, implicitly, the increased endotracheal tube resistance is still a matter of debate. This invitro study investigated work of breathing and inspiratory airway pressures in cuffed and uncuffed endotracheal tubes and the impact of pressure support ventilation and automatic tube compensation. In 5 simulated neonatal and pediatric lung models, the Active Servo Lung 5000 and an intensive care ventilator were used to quantify the differences in work of breathing under spontaneous breathing (with and without pressure support ventilation and automatic tube compensation) between cuffed and uncuffed endotracheal tubes. Additionally, differences in inspiratory airway pressures, measured either proximal or distal of the endotracheal tube, between cuffed and uncuffed endotracheal tubes under mechanical ventilation were investigated. Work of breathing was overall 10.27% [95% confidence interval 9.01-11.94] higher with cuffed than with uncuffed endotracheal tubes and was dramatically reduced by 34.19% [95% confidence interval 31.61-35.25] with the application of pressure support. Automatic tube compensation almost diminished work of breathing differences between the 2 endotracheal tube types in nearly all pediatric lung models. Peak inspiratory and mean airway pressures measured at the proximal endotracheal tube end revealed significantly higher values in cuffed than in uncuffed endotracheal tubes. However, these differences measured at the distal end of the endotracheal tube became minimal. This invitro study confirmed significant differences in work of breathing and inspiratory pressures between cuffed and uncuffed endotracheal tubes. Work of breathing, however, is almost neutralized by pressure support ventilation with automatic tube compensation and distal inspiratory airway pressures that, from a clinical perspective, are not significantly increased.

Spontaneous breathing trials after prolonged mechanical ventilation monitored by electrical impedance tomography: an observational study

The study objective was to examine the correlation between regional ventilation distribution measured with electrical impedance tomography (EIT) and weaning outcomes during spontaneous breathing trial (SBT). Fifteen patients received 100% automatic tube compensation (ATC) during the first and 70% during the second hour. Another 15 patients received external continuous positive airway pressure (CPAP) of 5 and 7.5 cmH2 O during the first and second hours, respectively. Regional ventilation distributions were monitored with EIT. Tidal volume and tidal variation of impedance correlated significantly during assist-control ventilation and ATC in all patients (r2 = 0.80 ± 0.18, P < 0.001). Higher support levels resulted in similar ventilation distribution and tidal volume, but higher end-expiratory lung impedance (EELI) (P < 0.05). Analysis of regional intratidal gas distribution revealed a redistribution of ventilation towards dorsal regions with lower support level in 13 of 30 patients. These patients had a higher weaning success rate (only 1 of 13 patients failed). Eight of 17 other patient failed (P < 0.05). The number of SBT days needed for weaning was significantly lower in the former group of 13 patients (13.1 ± 4.0 vs. 20.9 ± 11.2 days, P < 0.05). Regional ventilation distribution patterns during inspiration were associated with weaning outcomes, and they may be used to predict the success of extubation.

Use of automatic tube compensation (ATC) for weaning from mechanical ventilation in acute respiratory failure

Aim of studyTo evaluate the automatic tube compensation (ATC) as a method of weaning from mechanical ventilation in acute respiratory failure in comparison to pressure support volume (PSV). Patients and methods60 patients with, acute respiratory failure were enrolled in this study. Patients who met the criteria of weaning had one hour of a spontaneous breathing trial (SBT) either with ATC (n=35) or with PSV (n=25). Patients who passed the weaning trial were extubated and put on oxygen, while others who didn’t pass were put back on mechanical ventilation. ResultsThe SBT in the 60 enrolled patients weaning was successful in 35 patients (58.3%). 20 of the 35 patients (57.1%) who underwent ATC had successful weaning, and 15 out of the 25 patients (60%) who underwent PSV had also successful weaning. The difference had no statistical significance (p=0.7). Sensitivity of 80.36% with a positive predictive value (PPV) of 90.14% and a specificity of 79.63% with a negative predictive value (NPV) of 81.25% were shown in ATC, while PSV showed a sensitivity of 76.35% with a PPV of 88.63% and a specificity of 80.36% with a NPV of 71.4%. ATC was superior to PSV regarding PaO2/FIO2 ratio, oxygen saturation, oxygen tension, dynamic compliance and airway resistance. ConclusionATC is a useful mode of weaning in patients mechanically ventilated due to acute respiratory failure.

Trials directly comparing alternative spontaneous breathing trial techniques: a systematic review and meta-analysis

BackgroundThe effect of alternative spontaneous breathing trial (SBT) techniques on extubation success and other clinically important outcomes is uncertain.MethodsWe searched MEDLINE, EMBASE, CENTRAL, CINAHL, Evidence-Based Medicine Reviews, Ovid Health Star, proceedings of five conferences (1990–2016), and reference lists for randomized trials comparing SBT techniques in intubated adults or children. Primary outcomes were initial SBT success, extubation success, or reintubation. Two reviewers independently screened citations, assessed trial quality, and abstracted data.ResultsWe identified 31 trials (n = 3541 patients). Moderate-quality evidence showed that patients undergoing pressure support (PS) compared with T-piece SBTs (nine trials, n = 1901) were as likely to pass an initial SBT (risk ratio (RR) 1.00, 95% confidence interval (CI) 0.89–1.11; I2 = 77%) but more likely to be ultimately extubated successfully (RR 1.06, 95% CI 1.02–1.10; 11 trials, n = 1904; I2 = 0%). Exclusion of one trial with inconsistent results for SBT and extubation outcomes suggested that PS (vs T-piece) SBTs also improved initial SBT success (RR 1.06, 95% CI 1.01–1.12; I2 = 0%). Limited data suggest that automatic tube compensation plus continuous positive airway pressure (CPAP) vs CPAP alone or PS increase SBT but not extubation success.ConclusionsPatients undergoing PS (vs T-piece) SBTs appear to be 6% (95% CI 2–10%) more likely to be extubated successfully and, if the results of an outlier trial are excluded, 6% (95% CI 1–12%) more likely to pass an SBT. Future trials should investigate patients for whom SBT and extubation outcomes are uncertain and compare techniques that maximize differences in support.

The predictive value of serial changes in diaphragm function during the spontaneous breathing trial for weaning outcome: a study protocol

IntroductionThere is a variety of tools being used in clinical practice for the prediction of weaning success from mechanical ventilation. However, their diagnostic performances are less than satisfactory. The purpose...

Regional ventilation redistribution measured by electrical impedance tomography during spontaneous breathing trial with automatic tube compensation**This study was endorsed by the Far Eastern Memorial Hospital Research Ethics Review Committee, approval number: FEMH-IRB-103133-E.

Objective. Automatic tube compensation (ATC) was developed to overcome the flow resistance of endotracheal tube and decrease the imposed work of breathing. Although ATC is used as an evidence-based strategy to predict successful weaning from assisted ventilation, the changes in regional ventilation distribution induced by this technique are not known. We hypothesized that continuous positive airway pressure plus ATC (CPAP + 100%ATC) could reactivate the respiratory muscles in patients with prolonged mechanical ventilation (PMV) more effectively than volume assist-control mandatory ventilation (ACMV). Approach. A total of 16 PMV patients were included. Patients were ventilated under volume ACMV mode and subsequently under CPAP + 100%ATC for 50 min. Two periods of 5 min electrical impedance tomography (EIT) data at the end of each mode were analyzed. Main results. Tidal variations of electrical impedance determined by EIT during CPAP + 100%ATC were significantly smaller than during ACMV (p < 0.001), while no significant differences in end-expiratory lung impedance were found. Regional ventilation was distributed significantly more towards dorsal regions during CPAP + 100%ATC as indicated by the EIT-based index center of ventilation (46.2 ± 5.8 during ACMV versus 51.7 ± 6.5 during CPAP + 100%ATC, values in %, p < 0.001). However, the overall degree of ventilation inhomogeneity was not improved as indicated by the global inhomogeneity index (0.42 ± 0.09 during ACMV versus 0.42 ± 0.06 during CPAP + 100%ATC). The onset of ventilation was significantly less delayed during CPAP + 100%ATC in both ventral and dorsal regions as indicated by the ventilation delay index (ACMV versus CPAP + 100%ATC, 53.0 versus 42.6 in ventral; 50.2 versus 39.3 in dorsal regions; values in %, p < 0.001). Significance. Dorsal redistribution of ventilation and reduction of ventilation delay as identified by EIT indicate that CPAP + 100%ATC was effective in reactivating the respiratory muscles in the PMV patients of the present study.