Breathing Index Research Articles

Prevalence and prognosis of respiratory pendelluft phenomenon in mechanically ventilated ICU patients with acute respiratory failure: a retrospective cohort study

BackgroundRespiratory pendelluft phenomenon, defined as intrapulmonary gas redistribution caused by asynchronous alveolar ventilation, could be potentially harmful by inducing lung injury. The aim of the present study was to investigate its prevalence and prognosis in intensive care unit (ICU) patients with acute respiratory failure (ARF).MethodsThis was a retrospective observational study on 200 mechanically ventilated ARF patients treated in a tertiary ICU. The presence of pendelluft was determined using electrical impedance tomography (EIT) within 48 h after admission. Its amplitude was defined as the impedance difference between the sum of all regional tidal impedance variation and the global tidal impedance variation. A value above 2.5% (the 95th percentile from 30 healthy volunteers) was considered confirmative for its occurrence.ResultsPendelluft was found in 61 patients (39 in 94 patients with spontaneous breathing, 22 in 106 receiving controlled ventilation), with an overall prevalence of 31%. Existence of spontaneous breathing and higher global inhomogeneity index were associated with pendelluft. Patients with pendelluft had a longer ICU length of stay [10 (6, 14) vs. 7 (4, 11) days; median (lower, upper quartile); p = 0.022] and shorter 14-day ventilator-free days [8 (1, 10) vs. 10 (6, 12) days; p = 0.015]. Subgroup survival analysis suggested the association between pendelluft and longer ventilation duration, which was significant only in patients with PaO2/FiO2 ratio below 200 mmHg (log-rank p = 0.042). ICU mortality did not differ between the patients with and without pendelluft.ConclusionsRespiratory pendelluft occurred often in our study group and it was associated with longer ventilation duration. Early recognition of this phenomenon should trigger interventions aimed at alleviating pendelluft.

8: Ultrasonographic assessment of diaphragmatic parameters for predicting weaning outcome in patients on mechanical ventilation in the intensive care unit setting.

Background and Aims:The aim of this study was to ultrasonographically assess diaphragmatic parameters for predicting weaning outcome in patients on mechanical ventilation in the intensive care unit ( ICU ) setting. The primary objective was to assess the diagnostic accuracy of diaphragmatic excursion(DE) and diaphragmatic thickness fraction(DTF) by ultrasonography to predict weaning outcome in patients on mechanical ventilation. The secondary objectives were: To correlate diaphragmatic dysfunction with re-intubation within 48 hours of extubationTo assess which of the two - DE) or DTF is a better predictor of weaning.To compare diaphragmatic rapid shallow breathing index (RSBI) with clinical RSBI. Methods:This cohort study was conducted on 50 adult patients of either sex, admitted in the ICU and scheduled to undergo extubation. The patient’s readiness to wean was assessed by clinical judgment. When the patient was ready to be weaned, he/she was put on pressure support ventilation (PSV). The pressure support was gradually reduced to 6cm H2O. If the patient remained stable and extubation was planned, T-piece trial was given. Baseline parameters (Heart rate, non invasive blood pressure, respiratory rate, tidal volume, RSBI, SpO2, signs of respiratory distress- nasal flaring, sweating, agitation, use of accessory muscles,arterial blood gas analysis, Maximum Inspiratory Pressure (MIP), Maximum Expiratory Pressure(MEP) were recorded.Results:DE and DTF were assessed ultrasonographically and diaphragmatic RSBI was later calculated. DE andDTF were found to have similar sensitivity (94.12% and 97.06%), specificity (75%), positive predictive values(88.89 and 88.19% respectively) and negative predictive values (85.71% and 92.31% respectively). Overall DTF was comparable to DE in terms of diagnostic accuracy (88% and 90% respectively). (p value=1)Conclusion:DE and DTF are rapid and non invasive ultrasonographic indices with a high diagnostic accuracy for predicting weaning outcome. They provide objective and accurate results and are comparable to each other for predicting weaning outcome. Diaphragmatic RSBI is a good predictor of weaning outcome and is comparable to clinical RSBI.Weaning outcomeDiaphragmatic excursion (mm)Diaphragmatic thickness fraction (%)Sensitivity (95% CI)94.12% (80.32%-99.28%)97.06% (84.67%-99.93%)Specificity (95% CI)75% (47.62%-92.73%)75% (47.62%-92.73%)AUC (95% CI)0.85 (0.72-0.93)0.86 (0.73-0.94)Positive Predictive Value (95% CI)88.89% (73.94%-96.89%)89.19% (74.58%-96.97%)Negative Predictive Value (95% CI)85.71% (57.19%-98.22%)92.31% (63.97%-99.81%)Diagnostic accuracy88.00%90.00%P after Comparison of sensitivity1P after Comparison of specificity1

Abstract No.: ABS1330: A prospective observational study on ultra-sound of the diaphragm in weaning mechanically ventilated patients

Background and Aims:Weaning mechanically ventilated patients is a challenging task in the intensive care unit. Rapid shallow breathing index (RSBI) is a known weaning index to guide extubation. The aim of our study was to determine the use of diaphragm ultra-sound in weaning these patients.Methods:After obtaining ethics committee approval and Clinical Trials Registry India registration, this prospective study was performed on 200 patients on mechanical ventilation for more than 24 hours. After meeting clinical weaning criteria, spontaneous breathing trial (SBT) was performed for 1 hour to assess weaning and then trachea was extubated. Independent observers recorded RSBI and performed bedside ultra-sound of the diaphragm before extubation to measure diaphragm thickening fraction (DTF) and diaphragmatic excursion (DE). We assessed the predictability of weaning success with DTF and DE. Weaning failure was defined as the requirement of non-invasive ventilation or re-intubation within 48 h.Results:One hundred and seventy one patients out of 200 were successfully weaned. The area under the receiver operating characteristic curve (AUROC) values for RSBI, DTF, and DE for successful weaning prediction were 0.422, 0.654, and 0.809, respectively. The predictability using cut-off values were RSBI <82 (sensitivity 94%, specificity 31%, Youden’s index 0.25), DTF >37% (sensitivity 80%, specificity 52%, Youden’s index 0.31), and DE >1.21 cm (sensitivity 94%, specificity 71%, Youden’s index 0.65). The AUROC values for the combination of RSBI–DTF and RSBI–DE were 0.656 and 0.807, respectively.Conclusion:Diaphragm ultra-sound helps in determining weaning readiness in mechanically ventilated patients. Both DTF and DE showed a higher specificity than RSBI, and the combination of RSBI–DE and RSBI–DTF further increased the specificity in successful weaning.ParameterCut off rangeSensitivity %Specificity %PPV %NPV %Youden’s IndexAUROCRSBI<8294.031.089.045.00.250.422DTF (%)>37%79.551.790.730.00.310.654DE (cm)>1.2193.671.495.264.50.650.809RSBI-DTF> 0.85466.769.092.726.00.360.656RSBI-DE>0.73893.071.495.262.50.640.807

Ultrasound-assessed diaphragmatic dysfunction as a predictor of weaning outcome in mechanically ventilated patients with sepsis in intensive care unit

BackgroundWeaning from mechanical ventilation is one of the most common challenges in the intensive care unit (ICU). Most of predictive indices of weaning from mechanical ventilation are often inaccurate. This study was performed to assess the accuracy of diaphragmatic ultrasonography for predicting weaning outcome in mechanically ventilated patients with sepsis in ICU.ResultsSixty patients with sepsis in medical ICU were prospectively enrolled. All patients were ventilated in pressure support. Patients underwent a spontaneous breathing trial (SBT) on T-piece when they met all the following criteria: FiO2 < 0.6, PEEP ≤5 cmH2O, PaO2/FiO2 > 200, respiratory rate <30 breaths per minute, absence of fever, alert and cooperative, hemodynamic stability without or with low-dose vasoactive therapy support, and rapid shallow breathing index (RSBI)<105. During the trial, the patient was instructed to perform deep breathing to total lung capacity (TLC) and then exhaling to residual volume (RV) and the diaphragm was visualized in the 8th or 9th intercostal space between anterior and mid-axillary lines using a 3–5-MHz curved ultrasound probe to measure diaphragmatic excursion (DE) and a 7–11-MHz linear ultrasound probe to measure diaphragmatic thickness (DT) at TLC and RV, and the diaphragmatic thickness fraction (DTF) was calculated as percentage from the following formula (thickness at end inspiration—thickness at end expiration)/thickness at end expiration. According to weaning outcome, patients were divided into 2 groups: successful weaning group and weaning failure group. Weaning failure was defined as the inability to maintain spontaneous breathing for at least 48 h, without any form of ventilatory support.In the present study, right DTF of more than 37% and DE during deep breathing of more than 6.1 and 5.4 cm on the Rt and Lt side, respectively, were associated with successful weaning from MV. In the study, the sensitivities for right and left DE and DTF were 58.33, 62.5, and 58.33%, respectively, and the pooled specificities were 83.33, 83.33, and 100%, respectively, with p value = 0.032, 0.028, and 0.001, respectively. The area under curve (AUC) for Rt, Lt DE, and DTF were 0.701, 0.712, and 0.840, respectively. The present data indicate a satisfactory diagnostic accuracy in predicting extubation outcome.ConclusionsUltrasonography-based determination of diaphragm function by assessing DTF and DE can be used as predictor of weaning outcome in mechanically ventilated patients with sepsis.

Comparison of Clinico-Demographic Characteristics and Rapid Shallow Breathing Index of Patients on Mechanical Ventilation at Intensive Care Unit

Background: Mechanical ventilation (MV) is a life-saving intervention in the intensive care unit that should be considered for patients with respiratory failure.&#x0D; Objective: The purpose of the present study was to compare the clinico-demographic characteristics and rapid shallow breathing index of patients on mechanical ventilation at intensive care unit.&#x0D; Methodology: This prospective cohort study was conducted in the Department of Anesthesia, Pain Palliative &amp; Intensive Care Unit of Dhaka Medical College Hospital, Dhaka, Bangladesh from January 2014 to December 2015 for a period of two (2) years. Patients on mechanical ventilation more than 48 hours with the age of 18 to 60 years after fulfilling the inclusion and exclusion criteria were included as study population. One type of ventilator (eVent Medical) was used in all patients. Primary and daily setting of ventilators and the decision to weaning of the patient was made by the ICU consultants. The rapid shallow breathing index (RSBI) was measured by the ratio of respiratory frequency (f) to average exhaled tidal volume (EVT). When rapid shallow breathing index was 105 breath/min/L or less and more than 105 breath/min/L were taken as low and high RSBI respectively.&#x0D; Result: A total number of 117 patients were recruited for this study after fulfilling the inclusion and exclusion criteria of which 92 patients were in low RSBI group and the rest 25 patients were in high RSBI group. The mean age was found 31.8±12.8 years in low RSBI group and 35.9±13.2 years in high RSBI group (p&gt;0.05). It was observed that male was found 57(62.0%) in low RSBI group and 13(52.0%) in high RSBI group (p&gt;0.05). It was observed that 14(15.2%) patients had laparotomy in low RSBI group and 4(16.0%) in high RSBI group (p&gt;0.05). Surgical patients was found 27(29.3%) in low RSBI group and 11(44.0%) in high RSBI group (p&gt;0.05).&#x0D; Conclusion: In conclusion there is no statistical significant relationship of age, gender and clinical diseases of the patients with low and high rapid shallow breathing index who are under mechanical ventilation at intensive care unit.&#x0D; Journal of National Institute of Neurosciences Bangladesh, July 2021, Vol. 7, No. 2, pp. 92-96

Associations of insomnia symptoms with sociodemographic, clinical, and lifestyle factors in persons with HF: Health and retirement study.

Insomnia symptoms are very common in persons with heart failure (HF). However, many of the correlates and predictors of insomnia symptoms in this population remain unclear. The purpose of this study isto investigate the associations of sociodemographic, clinical, and lifestyle factors with insomnia symptoms in persons with HF. A theoretical framework was adapted from the neurocognitive model of chronic insomnia to guide the study. Data from the health and retirement study were used for the analysis. Parametric and nonparametric bivariate and multivariate analyses were conducted to investigate these associations. Age, depressive symptoms, comorbidity, dyspnea, pain, and smoking had significant bivariate associations with all insomnia symptoms. Race, Hispanic ethnicity, marital status, household income, poverty, and physical activity were associated with difficulty initiating sleep (DIS) and early morning awakening (EMA). Female sex, education, and alcohol consumption had a significant bivariate association with DIS. Sleep-disordered breathing and body mass index were significantly associated with EMA. Multivariate analysis suggested that depressive symptoms, comorbidity, dyspnea, and pain had independent associations with each insomnia symptom. Age explained DIS and difficulty maintaining sleep, and significant interaction effects between age and physical activity on DIS and EMA were revealed. Results suggest that insomnia symptoms are associated with several sociodemographic, clinical, and lifestyle factors. Age below 70 years, depressive symptoms, comorbidity, dyspnea, and pain might be considered as a phenotype to identify persons with HF who are at increased risk for insomnia symptoms.

Diaphragm ultrasound as a better predictor of successful extubation from mechanical ventilation than rapid shallow breathing index.

BackgroundIn 3%–19% of patients, reintubation is needed 48–72 hours following extubation, which increases intensive care unit (ICU) morbidity, mortality, and expenses. Extubation failure is frequently caused by diaphragm dysfunction. Ultrasonography can be used to determine the mobility and thickness of the diaphragm. This study looked at the role of diaphragm excursion (DE) and thickening fraction in predicting successful extubation from mechanical ventilation.MethodsThirty-one patients were extubated with the advice of an ICU consultant using the ICU weaning regimen and diaphragm ultrasonography was performed. Ultrasound DE and thickening fraction were measured three times: at the commencement of the T-piece experiment, at 10 minutes, and immediately before extubation. All patients' parameters were monitored for 48 hours after extubation. Rapid shallow breathing index (RSBI) was also measured at the same time.ResultsSuccessful extubation was significantly correlated with DE (P<0.001). Receiver curve analysis for DE to predict successful extubation revealed good properties (area under the curve [AUC], 0.83; P<0.001); sensitivity, 77.8%; specificity, 84.6%; positive predictive value (PPV), 84.6 %; negative predictive value (NPV), 73.3% while cut-off value, 11.43 mm. Diaphragm thickening fraction (DTF) also revealed moderate curve properties (AUC, 0.69; P=0.06); sensitivity, 61.1%; specificity, 84.6%; PPV, 87.5%; NPV, 61.1% with cut-off value 22.33% although former one was slightly better. RSBI could not reach good receiver operating characteristic value at cut-off points 100 breaths/min/L (AUC, 0.58; P=0.47); sensitivity, 66.7%; specificity, 53.8%; PPV, 66.7%; NPV, 53.8%).ConclusionsTo decrease the rate of reintubation, DE and DTF are better indicators of successful extubation. DE outperforms DTF.

Influencing factors for tracheostomy in patients with acute traumatic C3-C5 spinal cord injury and acute respiratory failure.

Patients with traumatic spinal cord injury (SCI) at C3-C5 have a wide range of tracheostomy rates (27%-75%), and the influencing factors for tracheostomy remain unclear. We conducted a retrospective case-control study to identify the influencing factors for tracheostomy in this subset of patient population. A total of 101 acute traumatic C3-C5 SCI patients with acute respiratory failure requiring translaryngeal intubation and invasive mechanical ventilation (IMV) for more than 48 hours were identified and divided into the no tracheostomy (No-TCO, n = 59) and tracheostomy group (TCO, n = 42) groups. Clinical data were retrospectively reviewed and analyzed. Compared with the No-TCO patients, the TCO patients had a higher proportion of C3 level injury, lower Glasgow Coma Scale (GCS), and lower blood hemoglobin levels at admission. During the first weaning attempt, the TCO patients had lower levels of maximal inspiratory pressure, maximal expiratory pressure, and minute ventilation but had a higher level of rapid shallow breathing index (RSBI). The TCO patients had longer durations of IMV, ICU stay, and hospitalization compared with the No-TCO patients. Moreover, due to prolonged IMV, the TCO patients had a higher incidence of complications, including ventilator-associated pneumonia, bacteremia, urinary tract infection, and acute kidney injury compared with the No-TCO patients. Multivariate logistic regression analysis revealed that low GCS at admission and high initial RSBI were independent risk factors for tracheostomy. Importantly, a combination of these two influencing factors synergistically increased the odds ratio for tracheostomy. Low GCS at admission and high initial RSBI are two independent influencing factors that synergistically impact tracheostomy in our patients. These findings are helpful for making the decision of performing tracheostomy in this subset of patient population.

Comparison of Volume Support, Volume-Assured Pressure Support, and Spontaneous Modes in Postoperative Early Extubated Patients.

This study aimed to compare respiratorily, arterial blood gas (ABG), and hemodynamics parameters among patients undergoing surgery who were admitted to intensive care unit (ICU), using three ventilation modes, including volume-assured pressure support (VAPS), volume support (VS), and spontaneous modes. One hundred and thirty-two patients were randomly assigned into three groups of VAPS, VS, and spontaneous modes utilizing randomized block procedure. Patients were followed between 12 and 30 h until extubation. Respiratory parameters including; peak inspiratory pressure (PIP), static compliance, resistance, rapid shallow breathing index (RSBI), and P 0.1(P0.1 correlates with respiratory drive and is defined as the negative pressure measured at the airway opening 100 ms after the initiation of an inspiratory effort), along with ABG parameters including; pH level, PaCO2,HCO3,PaO2/FiO2 ratio, extra hydrogen ion, and hemodynamics parameters including; mean arterial blood pressure and heart rate were measured every 3 h and compared among groups. All studied parameters in three groups improved during the study. PIP, Resistance, PH, HCO3, extra hydrogen ion, PCo2, PaO2/FiO2 ratio, mean arterial blood pressure were similar among the three groups in most of the time points (P > 0.05). In most of the time points, RSBI (from 92.7 to 55.4), P 0.1 (from 6.8 to 1.7) in the VAPS group, static compliance (from 55.3 to 55.7) in the VS group, and heart rate (from 108.5 to 90.1) in spontaneous groups were significantly better than other modes (P < 0.05). Changes in RSBI, P 0.1, PCo2, HCO3, and heart rate during the study were significantly different among studied groups (P < 0.05). The length of stay in the ICU in patients who underwent VAPS was significantly shorter than the other modes. VAPS mode with better effects or at least as effective as VS and spontaneous modes could be select as the best mode of ventilation in postoperative early extubated patients admitted to ICU.

Comparison of Ultrasound-based Diaphragmatic Thickness Fraction (DTF) with Rapid Shallow Breathing Index and DTF alone for Predicting Successful Weaning from Mechanical Ventilation: A Randomised Control Trial

Introduction: The timing for weaning from mechanical ventilator support is crucial because both early discontinuation and delayed weaning may lead to increased morbidity and mortality as well as high medical cost. Diaphragmatic Thickness Fraction (DTF), among the various ultrasound-based diaphragmatic measurements, can not only assess the readiness to wean but also predict the simple weaning. The Rapid Shallow Breathing Index (RSBI) or Yang Tobin index is a tool that is used in the weaning of mechanical ventilation. RSBI is the ratio of respiratory rate to tidal volume in litre (RR/VT). Aim: To estimate success of weaning process by using the ultrasound-guided DTF% alone as a weaning predictor, and compare it with the index derived from the combination of both DTF% and RSBI. Materials and Methods: This randomised control study was conducted on 100 patients admitted to Intensive Care Unit (ICU) during one year, from October 2019 to September 2020. When the patients satisfied the weaning criteria, they were given Spontaneous Breathing Trial (SBT). After SBT the ultrasound was done and RSBI were calculated. Composite Index (CI) was derived by combining DTF% and RSBI. Patients were divided in two groups. In “group C” CI was used as weaning predictor, and in “group D” DTF% alone was taken as weaning predictor. Incidence of weaning failure was noted in each group. The statistical analysis was done using Statistical Package for the Social Sciences (SPSS) Version 19.0. Chi-square test, Student’s t-test, Receiver Operating Characteristic (ROC) curve, 2x2 tables were used. Results: The DTF% value &gt;44.0% was found to be 95.2% sensitive, and 96.2% specific based on the ROC curve. The proportion of cases requiring reintubation was significantly higher in group D (DTF%) compared to group C (CI) (30.0% vs. 12.0%). RSBI with DTF% had a better sensitivity and specificity than DTF% alone. Conclusion: DTF% with RSBI is a much better predictor than DTF% alone. Sonography is subjective and has a long learning curve DTF% can be combined with RSBI to improve patient outcome.

Impact of Inspiratory Muscle Training on Weaning Parameters in Prolonged Ventilator-Dependent Patients: A Preliminary Study.

IntroductionPatients require prolonged mechanical ventilation to overcome respiratory failure in the chronic respiratory care ward; however, how to facilitate ventilator weaning using a nurse-led strategy is limited.ObjectivesThis study aimed to examine the impact of adjusting ventilator trigger sensitivity as inspiratory muscle training on weaning parameters in patients with prolonged ventilator dependence.MethodsMultiple pre-test–post-test with a non-equivalent control group design was conducted at a chronic respiratory care ward in southern Taiwan. A convenience sampling method was used to recruit patients who received prolonged mechanical ventilation for more than 21 days into control (n = 20) and intervention groups (n = 22). Adjustment of ventilator trigger sensitivity started from 10% of the initial maximum inspiratory pressure and increased to 40% after a training period of six weeks. The weaning parameters were collected for pre-test and multiple post-tests, and statistical analysis of treatment effects was performed using the generalized estimating equation.ResultsMagnitude of weaning parameters was significantly higher in the intervention group after the six-week training, including maximum inspiratory pressure, rapid shallow breathing index, tidal volume, and ratio of arterial-to-inspired oxygen.ConclusionAdjustment of ventilator trigger sensitivity as inspiratory muscle training can help prolonged ventilator-dependent patients improve their respiratory muscle strength, breathing patterns, and oxygenation.

Effects of transcutaneous electrical diaphragmatic stimulation on respiratory function in patients with prolonged mechanical ventilation.

PURPOSE:Muscle atrophy and diaphragm dysfunction are common with prolonged mechanical ventilation (PMV). Electrical stimulation on peripheral muscles has been shown to be beneficial in the improvement of muscle function. This study examined the effects of transcutaneous electrical diaphragmatic stimulation (TEDS) on respiratory muscle strength and weaning outcomes in patients with PMV.METHODS:Participants on ventilation for ≥21 days were randomly assigned to TEDS (n = 29) and control (n = 30) groups. The TEDS group received muscle electrical stimulation for 30 min/session/day throughout the intervention. Pulmonary function parameters (tidal volume, respiratory rate, and rapid shallow breathing index), and respiratory muscle strength (Pimax, Pemax) were assessed. The hospitalization outcome, including weaning rate and length of stay, was followed up until discharge.RESULTS:After TEDS, there was a significant increase in Pemax (10 [8–20] vs. 20 [10–22] cmH2O, P = 0.034) in the intervention group. At the end of the study, the improvement of minute volume in the TEDS group (0.64 (−0.67) was significantly higher than the control group (−0.64 (−2.5–0.78) (P = 0.008). In the control group, there was no significant difference between pre- and post-measurement of weaning parameters. There was a significant difference between groups in the weaning rate, with a higher rate in the TEDS group (90%) when compared with that in the control group (66.7%) (P =0.021).CONCLUSION:TEDS was significantly associated with increased respiratory muscle strength in patients with PMV. TEDS may be useful to facilitate weaning in this population.

Comparison of adaptive support ventilation and synchronized intermittent mandatory ventilation in patients with acute respiratory distress syndrome: A randomized clinical trial

Background:Suitable mechanical ventilation strategies can reduce the incidence and severity of ventilator-associated lung injury in patients with acute respiratory distress syndrome (ARDS). In this study, the effects of adaptive support ventilation (ASV) and synchronized intermittent mandatory ventilation (SIMV) on respiratory parameters and arterial blood gases (ABGs) parameters were compared in ARDS patients.Materials and Methods:Twenty-four patients were randomly divided into two groups of ASV and SIMV. Patients were followed up for 3 days, and respiratory parameters including rapid shallow breathing index (RSBI), spontaneous breathing rate (SBR), minute volume, and peak inspiratory pressure (PIP) as the primary outcomes and ABG parameters including PaO2, FiO2, PaCO2, HCO3, and PaO2/FiO2 ratio as the secondary outcomes were measured.Results:PIP in patients in the SIMV group on the 1st day (P = 0.013), 2nd day (P = 0.001), and 3rd day (P = 0.004) was statistically significantly more compared to those in patients in the ASV group. RSBI, SBR, and minute volume between the ASV and SIMV groups during the 3 days were not statistically significantly different (P > 0.05). The mean arterial blood pressure, heart rate, PaO2, and PH between both groups were similar (P > 0.05). At the end of the 2nd and 3rd days, the level of FiO2 and PaCO2 in ASV was significantly lower than those in ASV group. HCO3 in each of the 3 days in the ASV group was statistically significantly lower than that in the SIMV group (P < 0.050). PaO2/FiO2 ratio in patients in the ASV group in the 3 days was statistically significantly higher than that in the SIMV group (P < 0.050).Conclusion:By reducing PIP and improving oxygenation and ABG parameters, ASV mode may be a safe and feasible mode during mechanical ventilation in patients with ARDS.

Diaphragm ultrasound to predict weaning outcome: systematic review and meta-analysis.

Proper timing for discontinuation of mechanical ventilation is of great importance, especially in patients with previous weaning failures. Different indices obtained by ultra-sonographic evaluation of the diaphragm muscle have improved determination of weaning success. The aim of the present systematic review was to evaluate and compare the accuracy of the diagnostic indices obtained by ultrasonographic examination, including diaphragm thickening fraction (DTF), diaphragmatic excursion (DE) and the rapid shallow breathing index (RSBI). Asystematic literature search (Web of Science, MEDLINE, Embase and Google Scholar) was performed to identify original articles assessing diaphragm muscle features including excursion and thickening fraction. Atotal of 2738 citations were retrieved initially; available data of 19 cohort studies (1114 patients overall) were included in the meta-analysis, subdivided into groups based on the ultrasonographic examination type. Our results showed the superiority of the diagnostic accuracy of the DTF in comparison to the DE and the RSBI. Data on the combination of the different indices are limited. Diaphragmatic ultrasound is acheap and feasible tool for diaphragm function evaluation. Moreover, DTF in the assessment of weaning outcome provides more promising outcomes, which should be evaluated more meti-culously in future randomised trials.

Weaning Failure in Critically Ill Patients Is Related to the Persistence of Sepsis Inflammation.

Introduction: Septic patients undergoing mechanical ventilation (MV) often experience difficulty in weaning. Th aim of this study was to determine whether inflammatory biomarkers of sepsis could be indicative of the failure or success of spontaneous breathing trial (SBT) in these patients. Methods: Sixty-five patients on MV (42 septic and 23 intubated for other reasons) fulfilling the criteria for SBT were included in the study. Blood samples were collected right before, at the end of (30 min) and 24 h after the SBT. Serum inflammatory mediators associated with sepsis (IL-18, IL-18BP, TNF) were determined and correlated with the outcome of SBT. Results: A successful SBT was achieved in 45 patients (69.2%). Septic patients had a higher percentage of SBT failure as compared to non-septic patients (85% vs. 15%, p = 0.026), with an odds ratio for failing 4.5 times (OR = 4.5 95%CI: 1.16–17.68, p 0.022). IL-18 levels and the relative mRNA expression in serum were significantly higher in septic as compared to non-septic patients (p < 0.05). Sepsis was independently associated with higher serum IL-18 and TNF levels in two time-point GEE models (53–723, p = 0.023 and 0.3–64, p = 0.048, respectively). IL-18BP displayed independent negative association with rapid shallow breathing index (RSBI) (95% CI: −17.6 to −4, p = 0.002). Conclusion: Sustained increased levels of IL-18 and IL-18BP, acknowledged markers of sepsis, were found to be indicative of SBT failure in patients recovering from sepsis. Our results show that, although subclinical, remaining septic inflammation that sustaines for a long time complicates the weaning procedure. Biomarkers for the estimation of the septic burden and the right time for weaning are needed.

Pressure support ventilation in intensive care patients receiving prolonged invasive ventilation

Background: To our knowledge, the use and management of pressure support ventilation (PSV) in patients receiving prolonged (≥ 7 days) invasive mechanical ventilation has not previously been described. Objective: To collect and analyse data on the use and management of PSV in critically ill patients receiving prolonged ventilation. Design, setting and participants: We performed a multicentre retrospective observational study in Australia, with a focus on PSV in patients ventilated for ≥ 7 days. Main outcome measures: We obtained detailed data on ventilator management twice daily (8am and 8pm moments) for the first 7 days of ventilation. Results: Among 143 consecutive patients, 90/142 (63.4%) had received PSV by Day 7, and PSV accounted for 40.5% (784/1935) of ventilation moments. The most common pressure support level was 10 cmH2O (352/780) observations [45.1%]) with little variation over time, and 37 of 114 patients (32.4%) had no change in pressure support. Mean tidal volume during PSV was 8.3 (7.0-9.5) mL/kg predicted bodyweight (PBW) compared with 7.5 (7.0-8.3) mL/kg PBW during mandatory ventilation (P < 0.001). For 74.6% (247/331) of moments, despite a tidal volume of more than 8 mL/kg PBW, the pressure support level was not changed. Among 122 patients exposed to PSV, 97 (79.5%) received likely over-assistance according to rapid shallow breathing index criteria. Of 784 PSV moments, 411 (52.4%) were also likely over-assisted according to rapid shallow breathing index criteria, and 269/346 (77.7%) having no subsequent adjustment of pressure support. Conclusions: In patients receiving prolonged ventilation, almost two-thirds received PSV, which accounted for 40.5% of mechanical ventilation time. Half of the PSV-treated patients were exposed to high tidal volume and two-thirds to likely over-assistance. These observations provide evidence that can be used to inform interventional studies of PSV management.

Fetal Origins of Asthma: A Longitudinal Study From Birth to Age 36 Years

To determine the relationship between the low percentage of expiratory time necessary to reach tidal expiratory flow (tPTEF/tE) and flow at the end tidal point (VmaxFRC) in early infancy to the development of asthma, airflow limitation, and airway structural abnormalities in this 36-year birth cohort of the Tucson Children’s Respiratory Study.This is a birth cohort consisting of 1246 healthy infants born between 1980 to 1984 enrolled in the TCRS. Only 180 infants <6 months of age were tested by using the chest compression technique for pulmonary function testing because this technique was not developed until the end of the enrollment period.Demographic information was obtained via parent completed questionnaires. Infant lung function testing included tidal breathing indices, functional residual capacity via a helium-dilutions-gas-equilibration method, and partial expiratory-flow curves, from which the tPTEF/tE was determined. VmaxFRC was determined via partial expiratory flow-volume curves by using the chest compression technique. Active asthma was defined as a physician diagnosis of asthma at any age, with active symptoms within the previous year based on questionnaires obtained every 2 to 4 years between the ages of 6 and 36 years. Survey information, spirometry (prebronchodilator and postbronchodilator and full lung volumes), and high-resolution computed tomography of the chest was completed at the age of 26 years. Data were analyzed via multivariate linear regression models and generalized estimating equations.A total of 180 infants, who underwent pulmonary function testing, were compared with 1066 participants who did not undergo testing. The tested cohort revealed 8% with active asthma at the age of 6 years and 18% at the age of 36 years. Levels of infant tPTEF/tE and VmaxFRC were lower for participants who developed active asthma. tPTEF/tE and VmaxFRC were associated with a significant risk for active asthma (P = .003 and P =.007, respectively) and those in the lowest tertile of both indices were at highest risk (P = .009 and P = .01, respectively). Both tPTEF/tE and VmaxFRC were associated with an increased odds of developing active asthma between the ages of 6 and 36 years (70% [P = .001] and 55% [P = .005], respectively). At the age of 26 years, low infant tPTEF/tE was associated with reductions in airway diameter, total area, and luminal and wall areas, whereas VmaxFRC was associated with reduced forced expiratory volume in 1 second to forced vital capacity, forced expiratory volume in 1 second, and forced expiratory flow 25% to 75% levels.Reduced tPTEF/tE and VmaxFRC levels in infancy may indicate an increased risk for active asthma by the age of 36 years on the basis of pulmonary function testing and airway imaging in adulthood.Recognizing risk factors for asthma may extend beyond family history and personal history of atopy and respiratory infections. This study reveals that airflow limitation early in infancy may help predict asthma later in life and warrants further studies to standardize methods for clinical use and application. Understanding the time course of asthma development is essential in prevention and treatment.

Factors Related to Successful Ventilator Weaning in Respiratory Care Center Patients: A Retrospective Chart Review Study

The subacute respiratory care unit is an important relay station where respirator-dependent patients may access subsequent chronic respiratory care. Although there is relatively little information in the literature regarding respirator disconnections in subacute respiratory care units, assisting patients to disconnect successfully from respirators is a primary challenge for care teams. The purpose of this study was to understand respirator disconnections and the factors affecting these events in subacute respiratory care units to improve the effectiveness of ventilator weaning and reduce the burden on families and medical care providers. This was a retrospective chart review study. Patients admitted to the subacute respiratory care unit for respiratory training during the study period from January 2016 to December 2019 were recruited as subjects and the data were collected from the Chang Gung Medical Research Database`s health insurance secondary data using a self-made transcription form. The ventilator weaning success rate of the subjects in this study was 78.5%. A bivariate analysis revealed that consciousness status; disease severity; rapid shallow breathing index; days of hospitalization in a respiratory care center; days of ventilator use; blood urea nitrogen, white blood cell, hemoglobin, and blood albumin levels; and mean caloric intake were each significantly associated with successful ventilator withdrawal. The predictors of ventilator weaning in respiratory care center patients were identified as disease severity, rapid shallow breathing index, days of ventilator use, white blood cell level, and hemoglobin level. Respirator-dependent patients should be evaluated and monitored as early as possible. Moreover, a ventilator weaning plan should be included as a regular testing and monitoring item. Also, a respirator removal program should be provided on a case-by-case basis. Individualized ventilator weaning programs may reduce the burden on families and medical care providers.

Correlation between Handgrip Strength and Rapid Shallow Breathing Index for Assessment of Weaning from Mechanical Ventilation.

Background Assessment of weaning from mechanical ventilation (MV) is an important process. Rapid shallow breathing index (RSBI) is a standard tool to evaluate a patient's readiness before the spontaneous breathing trial (SBT). Handgrip strength (HGS) is an alternative method for assessment of respiratory muscle strength. Relationship between HGS and RSBI has not been explored. This study aimed to determine the correlation between HGS and RSBI to predict successful extubation in mechanically ventilated patients. Methods A prospective study was conducted in screened 120 patients requiring MV with tracheal intubation >48 h. HGS was performed at 48 h after intubation, 10 min before and 30 min after SBT, and 1 h after extubation. RSBI was performed at 10 min before SBT. Results A total of 93 patients (58% men) were included in the final analysis. Mean age was 71.6 ± 15.2 years. Patients admitted in general medical wards were 84.9%. APACHE II score was 13.5 ± 4.7. Most patients were intubated from pneumonia (39.8%). Weaning failure was 6.5%. The main result shows that HGS was negatively correlated with RSBI (regression coefficient −0.571, P < 0.001). The equation for predicting RSBI, derived from the linear regression model, was predicted RSBI (breaths/min/L) = 39.285 + (age ∗ 0.138)–(HGS ∗ 0.571). Conclusions HGS had significantly negative correlation with RSBI for assessment of weaning from MV. A prospective study of the HGS cutoff value is needed to investigate the difference between patients who succeeded and those who failed extubation. This trial is registered with TCTR20180323004.

The role of diaphragmatic ultrasound as a predictor of successful extubation from mechanical ventilation in respiratory intensive care unit

BackgroundThe diaphragm muscle whose dysfunction may be very common in patients undergoing mechanical ventilation (Ferrari G, De Filippi G, Elia F, Panero F, Volpicelli G, Aprà F. Crit Ultrasound J 6:8, 2014). Aim: To evaluate real-time ultrasound in the evaluation of diaphragmatic thickening, thickening fraction, and/or excursion to predict extubation outcomes. We aimed to compare these parameters with other traditional weaning measures is a fundamental.ResultsOut of 80 included patients, 20 (25%) have failed extubation. Diaphragmatic thickening (DT), thickening fraction (DTF), and/or excursion (DE) were significantly higher in the successful group compared to those who failed extubation (p < 0.05). Cutoff values of diaphragmatic measures associated with successful extubation (during tidal breathing) were ≥ 17 mm for DE; ≥ 2.1 cm for DT inspiration; ≥ 15.5 mm for DT expiration, functional residual capacity (FRC); and ≥ 32.82% for DTF %, giving 68%, 95%, 62%, and 90% sensitivity, respectively, and 65%, 100%, 100%, and 75% specificity, respectively. Cutoff values of diaphragmatic parameters associated with successful extubation (during deep breathing) were > 28.5 mm DT Insp, total lung capacity (TLC); >22.5mm DT Exp (RV); >37 DTF %; and > 31 mm DE, giving 100%, 73%, 97%, and 75% sensitivity and 65%, 75%, 100%, and 55% specificity, respectively. Rapid shallow breathing index (RSBI) had 47% sensitivity but 90% specificity.ConclusionUltrasound evaluation of diaphragmatic parameters could be a good predictor of weaning in patients who passed the T-tube.