New insights into weaning from mechanical ventilation: left ventricular diastolic dysfunction is a key player

Prevalence of Diastolic Dysfunction in Critically Ill Patients Admitted to Intensive Care Unit from a Tertiary Care Hospital: A Prospective Observational Study

Aim

Critically ill individuals may have left ventricular diastolic dysfunction (LVDD) which can prolong their intensive care unit (ICU) stay. The purpose of this study was to determine the prevalence of LVDD in critically ill adult patients requiring mechanical ventilation in ICU, the effect of LVDD on 28-day survival, and weaning from mechanical ventilation.

Methodology

A total of 227 adults who had been on mechanical ventilation for more than 48 hours in an ICU were recruited for this study. The study's parameters were recorded on the third day of mechanical ventilation using a low-frequency phased array probe. A simplified definition of LVDD in critically ill adults was utilized to determine the presence or absence of LVDD. Weaning failure and 28-day mortality were noted.

Results

The prevalence of LVDD in adults requiring mechanical ventilation in the ICU was found to be 35.4% (n = 79). Patients with LVDD had the odds of having a 28-day mortality increase by 7.48 (95% CI: 3.24-17.26, p < 0.0001). Patients with LVDD had the odds of having weaning failure increase by 5.37 (95% CI: 2.17-13.26, p = 0.0003).

Conclusion

Measures should be taken to detect critically ill adults with LVDD with systolic dysfunction or heart failure with preserved ejection fraction early so that their fluid balance, myocardial contractility, and afterload can be optimized to minimize their morbidity and mortality.

Highlights

Critically ill adults with LVDD may have adverse outcomes. Hence, protocol should be in place for diagnosing LVDD early in critically ill adults thereby, measures can be taken to minimize morbidity in those patients.

How to cite this article

Luitel B, Senthilnathan M, Cherian A, Suganya S, Adole PS. Prevalence of Diastolic Dysfunction in Critically Ill Patients Admitted to Intensive Care Unit from a Tertiary Care Hospital: A Prospective Observational Study. Indian J Crit Care Med 2024;28(9):832-836.

Ultrasound evaluation of cardiac and diaphragmatic function at different positions during a spontaneous breathing trial predicting extubation outcomes: a retrospective cohort study

BACKGROUND

The ratio (E/Ea) of mitral Doppler inflow velocity to annular tissue Doppler wave velocity by transthoracic echocardiography and diaphragmatic excursion (DE) by diaphragm ultrasound have been confirmed to predict extubation outcomes. However, few studies focused on the predicting value of E/Ea and DE at different positions during a spontaneous breathing trial (SBT), as well as the effects of △E/Ea and △DE (changes in E/Ea and DE during a SBT).

METHODS

This study was a reanalysis of the data of 60 difficult-to-wean patients in a previous study published in 2017. All eligible participants were organized into respiratory failure (RF) group and extubation success (ES) group within 48 h after extubation, or re-intubation (RI) group and non-intubation (NI) group within 1 week after extubation. The risk factors for respiratory failure and re-intubation including E/Ea and △E/Ea, DE and △DE at different positions were analyzed by multivariate logistic regression, respectively. The receiver operating characteristic (ROC) curves of E/Ea (septal, lateral, average) and DE (right, left, average) were compared with each other, respectively.

RESULTS

Of the 60 patients, 29 cases developed respiratory failure within 48 h, and 14 of those cases required re-intubation within 1 week. Multivariate logistic regression showed that E/Ea were all associated with respiratory failure, while only DE (right) and DE (average) after SBT were related to re-intubation. There were no statistic differences among the ROC curves of E/Ea at different positions, nor between the ROC curves of DE. No statistical differences were shown in △E/Ea between RF and ES groups, while △DE (average) was remarkably higher in NI group than that in RI group. However, multivariate logistic regression analysis showed that △DE (average) was not associated with re-intubation.

CONCLUSIONS

E/Ea at different positions during a SBT could predict postextubation respiratory failure with no statistical differences among them. Likewise, only DE (right) and DE (average) after SBT might predict re-intubation with no statistical differences between each other.

MUltiparametric Score for Ventilation Discontinuation in Intensive Care Patients: A Protocol for an Observational Study

BACKGROUND

Mechanical ventilation significantly improves patient survival but is associated with complications, increasing healthcare costs and morbidity. Identifying optimal weaning times is paramount to minimize these risks, yet current methods rely heavily on clinical judgment, lacking specificity.

METHODS

This study introduces a novel multiparametric predictive score, the MUSVIP (MUltiparametric Score for Ventilation discontinuation in Intensive care Patients), aimed at accurately predicting successful extubation. Conducted at Santo Stefano Hospital's ICU, this single-center, observational, prospective cohort study will span over 12 months, enrolling adult patients undergoing invasive mechanical ventilation. The MUSVIP integrates variables measured before and during a spontaneous breathing trial (SBT) to formulate a predictive score.

RESULTS

Preliminary analyses suggest an Area Under the Curve (AUC) of 0.815 for the MUSVIP, indicating high predictive capacity. By systematically applying this score, we anticipate identifying patients likely to succeed in weaning earlier, potentially reducing ICU length of stay and associated healthcare costs.

CONCLUSION

This study's findings could significantly influence clinical practices, offering a robust, easy-to-use tool for optimizing weaning processes in ICUs.

Combined cardiac, lung, and diaphragm ultrasound for predicting weaning failure during spontaneous breathing trial

BACKGROUND

Weaning from invasive mechanical ventilation (MV) is a complex and challenging process that involves multiple pathophysiological mechanisms. A combined ultrasound evaluation of the heart, lungs, and diaphragm during the weaning phase can help to identify risk factors and underlying mechanisms for weaning failure. This study aimed to investigate the accuracy of lung ultrasound (LUS), transthoracic echocardiography (TTE), and diaphragm ultrasound for predicting weaning failure in critically ill patients.

METHODS

Patients undergoing invasive MV for > 48 h and who were readied for their first spontaneous breathing trial (SBT) were studied. Patients were scheduled for a 2-h SBT using low-level pressure support ventilation. LUS and TTE were performed prospectively before and 30 min after starting the SBT, and diaphragm ultrasound was only performed 30 min after starting the SBT. Weaning failure was defined as failure of SBT, re-intubation, or non-invasive ventilation within 48 h.

RESULTS

Fifty-one patients were included, of whom 15 experienced weaning failure. During the SBT, the global, anterior, and antero-lateral LUS scores were higher in the failed group than in the successful group. Receiver operating characteristic curve analysis showed that the areas under the curves for diaphragm thickening fraction (DTF) and global and antero-lateral LUS scores during the SBT to predict weaning failure were 0.678, 0.719, and 0.721, respectively. There was no correlation between the LUS scores and the average E/e' ratio during the SBT. Multivariate analysis identified antero-lateral LUS score > 7 and DTF < 31% during the SBT as independent predictors of weaning failure.

CONCLUSION

LUS and diaphragm ultrasound can help to predict weaning failure in patients undergoing an SBT with low-level pressure support. An antero-lateral LUS score > 7 and DTF < 31% during the SBT were associated with weaning failure.

The Role of Ultrasonography in the Process of Weaning from Mechanical Ventilation in Critically Ill Patients

Weaning patients from mechanical ventilation (MV) is a complex process that may result in either success or failure. The use of ultrasound at the bedside to assess organs may help to identify the underlying mechanisms that could lead to weaning failure and enable proactive measures to minimize extubation failure. Moreover, ultrasound could be used to accurately identify pulmonary diseases, which may be responsive to respiratory physiotherapy, as well as monitor the effectiveness of physiotherapists' interventions. This article provides a comprehensive review of the role of ultrasonography during the weaning process in critically ill patients.

B-lines by lung ultrasound as a predictor of re-intubation in mechanically ventilated patients with heart failure

Introduction

There have been few studies on predictors of weaning failure from MV in patients with heart failure (HF). We sought to investigate the predictive value of B-lines measured by lung ultrasound (LUS) on the risk of weaning failure from mechanical ventilation (MV) and in-hospital outcomes.

Methods

This was a single-center, prospective observational study that included HF patients who were on invasive MV. LUS was performed immediate before ventilator weaning. A positive LUS exam was defined as the observation of two or more regions that had three or more count of B-lines located bilaterally on the thorax. The primary outcome was early MV weaning failure, defined as re-intubation within 72 h.

Results

A total of 146 consecutive patients (mean age 70 years; 65.8% male) were enrolled. The total count of B-lines was a median of 10 and correlated with NT-pro-BNP level (r2 = 0.132, p < 0.001). Early weaning failure was significantly higher in the positive LUS group (9 out of 64, 14.1%) than the negative LUS group (2 out of 82, 2.4%) (p = 0.011). The rate of total re-intubation during the hospital stay (p = 0.004), duration of intensive care unit stay (p = 0.004), and hospital stay (p = 0.010) were greater in the positive LUS group. The negative predictive value (NPV) of positive LUS was 97.6% for the primary outcome.

Conclusion

B-lines measured by LUS can predict the risk of weaning failure. Considering the high NPV of positive LUS, it may help guide the decision of weaning in patients on invasive MV due to acute decompensated HF.

Cardiopulmonary interactions during ventilator weaning

Weaning a critically-ill patient from the ventilator is a crucial step in global management. This manuscript details physiological changes induced by altered heart-lung interactions during the weaning process, illustrates the main mechanisms which could lead to weaning failure of cardiac origin, and discuss a tailored management based on the monitoring of changes in central hemodynamics during weaning. The transition from positive-pressure ventilation to spontaneous breathing results in abrupt hemodynamic and metabolic changes secondary to rapidly modified heart-lung interactions, sudden changes in cardiac loading conditions, and increased oxygen demand. These modifications may elicit an excessive burden on both the respiratory and cardiovascular systems, result in a rapid and marked increase of left ventricular filling pressure, and ultimately result in a weaning-induced pulmonary oedema (WIPO). The T-piece trial induces the greatest burden on respiratory and cardiocirculatory function when compared to spontaneous breathing trial using pressure support ventilation with positive or zero end-expiratory pressure. Since LV overload is the mainstay of WIPO, positive fluid balance and SBT-induced acute hypertension are the most frequently reported mechanisms of weaning failure of cardiac origin. Although the diagnosis of WIPO historically relied on an abrupt elevation of pulmonary artery occlusion pressure measured during right heart catheterization, it is nowadays commonly documented by echocardiography Doppler. This non-invasive approach is best suited for identifying high-risk patients, depicting the origin of WIPO, and tailoring individual management. Whether this strategy increases the success rate of weaning needs to be evaluated in a population at high risk of weaning failure of cardiac origin.

Influence of reduced muscle mass and quality on ventilator weaning and complications during intensive care unit stay in COVID-19 patients

BACKGROUND & AIMS

Sarcopenia, a loss of muscle mass, quality and function, which is particularly evident in respiratory muscles, has been associated with many clinical adverse outcomes. In this study, we aimed at evaluating the role of reduced muscle mass and quality in predicting ventilation weaning, complications, length of intensive care unit (ICU) and of hospital stay and mortality in patients admitted to ICU for SARS-CoV-2-related pneumonia.

METHODS

This was an observational study based on a review of medical records of all adult patients admitted to the ICU of a tertiary hospital in Milan and intubated for SARS-CoV-2-related pneumonia during the first wave of the COVID-19 pandemic. Muscle mass and quality measurement were retrieved from routine thoracic CT scans, when sections passing through the first, second or third lumbar vertebra were available.

RESULTS

A total of 81 patients were enrolled. Muscle mass was associated with successful extubation (OR 1.02, 95% C.I. 1.00-1.03, p = 0.017), shorter ICU stay (OR 0.97, 95% C.I. 0.95-0.99, p = 0.03) and decreased hospital mortality (HR 0.98, 95% C.I. 0.96-0.99, p = 0.02). Muscle density was associated with successful extubation (OR 1.07, 95% C.I. 1.01-1.14; p = 0.02) and had an inverse association with the number of complications in ICU (Β -0.07, 95% C.I. -0.13 - -0.002, p = 0.03), length of hospitalization (Β -1.36, 95% C.I. -2.21 - -0.51, p = 0.002) and in-hospital mortality (HR 0.88, 95% C.I. 0.78-0.99, p = 0.046).

CONCLUSIONS

Leveraging routine CT imaging to measure muscle mass and quality might constitute a simple, inexpensive and powerful tool to predict survival and disease course in patients with COVID-19. Preserving muscle mass during hospitalisation might have an adjuvant role in facilitating remission from COVID-19.

Update on the use of ultrasound in the diagnosis and monitoring of the critical patient

Hemodynamic and respiratory complications are the main causes of morbidity and mortality in in critical care units (CCU). Imaging techniques are a key tool in differential diagnosis and treatment. In the last decade, ultrasound has shown great potential for bedside diagnosis of respiratory disease, as well as for the hemodynamic assessment of critically ill patients. Ultrasound has proven to be a useful guide for identifying the type of shock, estimating cardiac output, guiding fluid therapy and vasoactive drugs, providing security in the performance of percutaneous techniques (thoracentesis, pericardiocentesis, evacuation of abscesses/hematomas), detecting dynamically in real time pulmonary atelectasis and its response to alveolar recruitment maneuvers, and predicting weaning failure from mechanical ventilation. Due to its dynamic nature, simple learning curve and absence of ionizing radiation, it has been incorporated as an essential tool in daily clinical practice in CCUs. The objective of this review is to offer a global vision of the role of ultrasound and its applications in the critically ill patient.

Left Ventricular Diastolic Dysfunction in ARDS Patients

Background: The aim of this study was to evaluate the possible presence of diastolic dysfunction and its possible effects in terms of respiratory mechanics, gas exchange and lung recruitability in mechanically ventilated ARDS. Methods: Consecutive patients admitted in intensive care unit (ICU) with ARDS were enrolled. Echocardiographic evaluation was acquired at clinical PEEP level. Lung CT-scan was performed at 5 and 45 cmH₂O. In the study, 2 levels of PEEP (5 and 15 cmH₂O) were randomly applied. Results: A total of 30 patients were enrolled with a mean PaO₂/FiO₂ and a median PEEP of 137 ± 52 and 10 [9–10] cmH₂O, respectively. Of those, 9 patients (30%) had a diastolic dysfunction of grade 1, 2 and 3 in 33%, 45% and 22%, respectively, without any difference in gas exchange and respiratory mechanics. The total lung weight was significantly higher in patients with diastolic dysfunction (1669 [1354–1909] versus 1554 [1146–1942] g) but the lung recruitability was similar between groups (33.3 [27.3–41.4] versus 30.6 [20.0–38.8] %). Left ventricular ejection fraction (57 [39–62] versus 60 [57–60]%) and TAPSE (20.0 [17.0–24.0] versus 24.0 [20.0–27.0] mL) were similar between the two groups. The response to changes of PEEP from 5 to 15 cmH₂O in terms of oxygenation and respiratory mechanics was not affected by the presence of diastolic dysfunction. Conclusions: ARDS patients with left ventricular diastolic dysfunction presented a higher amount of lung edema and worse outcome.

Predictive Factors of Extubation Failure in COVID-19 Mechanically Ventilated Patients

Purpose: We investigated whether COVID-19 patients on mechanical ventilation (MV) had a different extubation outcome compared to non-COVID-19 patients while identifying predictive factors of extubation failure in the former. Methods: A retrospective, single-center, and observational study was done on 216 COVID-19 patients admitted to an intensive care unit (ICU) between March 2020 and March 2021, aged ≥ 18 years, in use of invasive MV for more than 24 h, which progressed to weaning. The primary outcome that was evaluated was extubation failure during ICU stay. A statistical analysis was performed to evaluate the association of patient characteristics with extubation outcome, and a Poisson regression model determined the predictive value. Results: Seventy-seven patients were extubated; the mean age was 57.2 years, 52.5% were male, and their mean APACHE II score at admission was 17.8. On average, MV duration until extubation was 8.7 ± 3.7 days, with 14.9 ± 10.1 days of ICU stay and 24.6 ± 14.0 days with COVID-19 symptoms. The rate of extubation failure (ie, the patient had to be reintubated during their ICU stay) was 22.1% (n = 17), while extubation was successful in 77.9% (n = 60) of cases. Failure was observed in only 7.8% of cases when evaluated 48 hours after extubation. The mean reintubation time was 4.28 days. After adjusting the analysis for age, sex, during of symptoms, days under MV, dialysis, and PaO2/FiO2 ratio, some parameters independently predicted extubation failure: age ≥ 66 years (APR = 5.12 [1.35-19.46]; p = 0.016), ≥ 31 days of symptoms (APR = 5.45 [0.48-62.19]; p = 0.016), and need for dialysis (APR = 5.10 [2.00-13.00]; p = 0.001), while a PaO2/FiO2 ratio >300 decreased the probability of extubation failure (APR = 0.14 [0.04-0.55]; p = 0.005). The presence of three predictors (ie, age ≥ 66 years, time of symptoms ≥ 31 days, need of dialysis, and PaO2/FiO2 ratio < 200) increased the risk of extubation failure by a factor of 23.0 (95% CI, 3.34-158.5). Conclusion: COVID-19 patients had an extubation failure risk that was almost three times higher than non-COVID-19 patients, with the extubation of the former being delayed compared to the latter. Furthermore, an age ≥ 66 years, time of symptoms ≥ 31 days, need of dialysis, and PaO2/FiO2 ratio > 200 were independent predictors for extubation failure, and the presence of three of these characteristics increased the risk of failure by a factor of 23.0.

The weaning from mechanical ventilation: a comprehensive ultrasound approach

PURPOSE OF REVIEW

Due to heart, lung and diaphragm interactions during weaning from mechanical ventilation, an ultrasound integrated approach may be useful in the detection of dysfunctions potentially leading to weaning failure. In this review, we will summarize the most recent advances concerning the ultrasound applications relevant to the weaning from mechanical ventilation.

RECENT FINDINGS

The role of ultrasonographic examination of heart, lung and diaphragm has been deeply investigated over the years. Most recent findings concern the ability of lung ultrasound in detecting weaning induced pulmonary edema during spontaneous breathing trial. Furthermore, in patients at high risk of cardiac impairments, global and anterolateral lung ultrasound scores have been correlated with weaning and extubation failure, whereas echocardiographic indexes were not. For diaphragmatic ultrasound evaluation, new indexes have been proposed for the evaluation of diaphragm performance during weaning, but further studies are needed to validate these results.

SUMMARY

The present review summarizes the potential role of ultrasonography in the weaning process. A multimodal integrated approach allows the clinician to comprehend the pathophysiological processes of weaning failure.

The effects of positive end-expiratory pressure on cardiac function: a comparative echocardiography-conductance catheter study

Background

Echocardiographic parameters of diastolic function depend on cardiac loading conditions, which are altered by positive pressure ventilation. The direct effects of positive end-expiratory pressure (PEEP) on cardiac diastolic function are unknown.

Methods

Twenty-five patients without apparent diastolic dysfunction undergoing coronary angiography were ventilated noninvasively at PEEPs of 0, 5, and 10 cmH₂O (in randomized order). Echocardiographic diastolic assessment and pressure–volume-loop analysis from conductance catheters were compared. The time constant for pressure decay (τ) was modeled with exponential decay. End-diastolic and end-systolic pressure volume relationships (EDPVRs and ESPVRs, respectively) from temporary caval occlusion were analyzed with generalized linear mixed-effects and linear mixed models. Transmural pressures were calculated using esophageal balloons.

Results

τ values for intracavitary cardiac pressure increased with the PEEP (n = 25; no PEEP, 44 ± 5 ms; 5 cmH₂O PEEP, 46 ± 6 ms; 10 cmH₂O PEEP, 45 ± 6 ms; p < 0.001). This increase disappeared when corrected for transmural pressure and diastole length. The transmural EDPVR was unaffected by PEEP. The ESPVR increased slightly with PEEP. Echocardiographic mitral inflow parameters and tissue Doppler values decreased with PEEP [peak E wave (n = 25): no PEEP, 0.76 ± 0.13 m/s; 5 cmH₂O PEEP, 0.74 ± 0.14 m/s; 10 cmH₂O PEEP, 0.68 ± 0.13 m/s; p = 0.016; peak A wave (n = 24): no PEEP, 0.74 ± 0.12 m/s; 5 cmH₂O PEEP, 0.7 ± 0.11 m/s; 10 cmH₂O PEEP, 0.67 ± 0.15 m/s; p = 0.014; E’ septal (n = 24): no PEEP, 0.085 ± 0.016 m/s; 5 cmH₂O PEEP, 0.08 ± 0.013 m/s; 10 cmH₂O PEEP, 0.075 ± 0.012 m/s; p = 0.002].

Conclusions

PEEP does not affect active diastolic relaxation or passive ventricular filling properties. Dynamic echocardiographic filling parameters may reflect changing loading conditions rather than intrinsic diastolic function. PEEP may have slight positive inotropic effects.

Clinical trial registration

https://clinicaltrials.gov/ct2/show/NCT02267291, registered 17. October 2014.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00392-022-02014-1.

A Simple Algorithm Using Ventilator Parameters to Predict Successfully Rapid Weaning Program in Cardiac Intensive Care Unit Patients

BACKGROUND

Ventilator weaning is one of the most significant challenges in the intensive care unit (ICU). Approximately 30% of patients fail to wean, resulting in prolonged use of ventilators and increased mortality. There are numerous high-performance prediction models available today, but they require a large number of parameters to predict and are thus impractical in clinical practice.

OBJECTIVES

This study aims to create an artificial intelligence (AI) model for predicting weaning time and to identify the most simplified key predictors that will allow the model to achieve adequate accuracy with as few parameters as possible.

METHODS

This is a retrospective study of to-be-weaned patients (n = 1439) hospitalized in the cardiac ICU of Cheng Hsin General Hospital's Department of Cardiac Surgery from November 2018 to August 2020. The patients were divided into two groups based on whether they could be weaned within 24 h (i.e., "patients weaned within 24 h" (n = 1042) and "patients not weaned within 24 h" (n = 397)). Twenty-eight variables were collected including demographic characteristics, arterial blood gas readings, and ventilation set parameters. We created a prediction model using logistic regression and compared it to other machine learning techniques such as decision tree, random forest, support vector machine (SVM), extreme gradient boosting, and artificial neural network. Forward, backward, and stepwise selection methods were used to identify significant variables, and the receiver operating characteristic curve was used to assess the accuracy of each AI model.

RESULTS

The SVM [receiver operating characteristic curve (ROC-AUC) = 88%], logistic regression (ROC-AUC = 86%), and XGBoost (ROC-AUC = 85%) models outperformed the other five machine learning models in predicting weaning time. The accuracies in predicting patient weaning within 24 h using seven variables (i.e., expiratory minute ventilation, expiratory tidal volume, ventilation rate set, heart rate, peak pressure, pH, and age) were close to those using 28 variables.

CONCLUSIONS

The model developed in this research successfully predicted the weaning success of ICU patients using a few and easily accessible parameters such as age. Therefore, it can be used in clinical practice to identify difficult-to-wean patients to improve their treatment.

Application of POCUS in patients with COVID-19 for acute respiratory distress syndrome management: a narrative review

COVID-19 has inflicted the world for over two years. The recent mutant virus strains pose greater challenges to disease prevention and treatment. COVID-19 can cause acute respiratory distress syndrome (ARDS) and extrapulmonary injury. Dynamic monitoring of each patient's condition is necessary to timely tailor treatments, improve prognosis and reduce mortality. Point-of-care ultrasound (POCUS) is broadly used in patients with ARDS. POCUS is recommended to be performed regularly in COVID-19 patients for respiratory failure management. In this review, we summarized the ultrasound characteristics of COVID-19 patients, mainly focusing on lung ultrasound and echocardiography. Furthermore, we also provided the experience of using POCUS to manage COVID-19-related ARDS.

Italian Society of Anesthesia, Analgesia, Resuscitation, and Intensive Care expert consensus statement on the use of lung ultrasound in critically ill patients with coronavirus disease 2019 (ITACO)

BACKGROUND

To produce statements based on the available evidence and an expert consensus (as members of the Lung Ultrasound Working Group of the Italian Society of Analgesia, Anesthesia, Resuscitation, and Intensive Care, SIAARTI) on the use of lung ultrasound for the management of patients with COVID-19 admitted to the intensive care unit.

METHODS

A modified Delphi method was applied by a panel of anesthesiologists and intensive care physicians expert in the use of lung ultrasound in COVID-19 intensive critically ill patients to reach a consensus on ten clinical questions concerning the role of lung ultrasound in the following: COVID-19 diagnosis and monitoring (with and without invasive mechanical ventilation), positive end expiratory pressure titration, the use of prone position, the early diagnosis of pneumothorax- or ventilator-associated pneumonia, the process of weaning from invasive mechanical ventilation, and the need for radiologic chest imaging.

RESULTS

A total of 20 statements were produced by the panel. Agreement was reached on 18 out of 20 statements (scoring 7-9; "appropriate") in the first round of voting, while 2 statements required a second round for agreement to be reached. At the end of the two Delphi rounds, the median score for the 20 statements was 8.5 [IQR 8.9], and the agreement percentage was 100%.

CONCLUSION

The Lung Ultrasound Working Group of the Italian Society of Analgesia, Anesthesia, Resuscitation, and Intensive Care produced 20 consensus statements on the use of lung ultrasound in COVID-19 patients admitted to the ICU. This expert consensus strongly suggests integrating lung ultrasound findings in the clinical management of critically ill COVID-19 patients.

Ultrasound-Guided Preload Indices during Different Weaning Protocols of Mechanically Ventilated Patients and its Impact on Weaning Induced Cardiac Dysfunction

BACKGROUND: Elevation of the left ventricular (LV) filling pressure can occur during weaning of mechanical ventilation due to increase in LV preload and/or changes in LV compliance and LV afterload. AIM: The aim of the study was to evaluate respiratory changes in internal jugular vein and inferior vena cava during weaning from mechanical ventilation. METHODS: Prospective observational study conducted on 80 consecutive patients. Patients were divided randomly into two groups who met the readiness criteria to start spontaneous breathing trial (SBT) either on pressure support ventilation (PS/CPAP) for 30 min or T-piece for 120 min. Weaning failure was defined as a failed SBT or reintubation within 48 h. Echocardiographic evaluation was done on assisted controlled ventilation and at the end of SBT for preload assessment. RESULTS: Mitral Septal E/E’ Cutoff value ≥6.1 with sensitivity 81% and specificity 84.2%, and AUC 0.73 for predicting weaning failure. IVC distensibility index on CPAP cutoff value ≥66.5% with sensitivity 100% and specificity 68.4%, and AUC 0.85. In Group II, Mitral Septal E/E’ Cut off value ≥5.8 with sensitivity 83% and specificity 90.9%, AUC 0.83, IVC collapsibility index Cut off value ≥45.5% with sensitivity 72% and specificity 86%, AUC 0.73. CONCLUSION: Mitral Septal E/E’ could predict weaning-induced diastolic dysfunction. IVC plays an important role in predicting weaning failure.

Does diaphragm ultrasound improve the rapid shallow breathing index accuracy for predicting the success of weaning from mechanical ventilation?

BACKGROUND

This prospective study investigated whether taking into account diaphragmatic excursion (DE) measured by ultrasonography would improve the performance of the rapid shallow breathing index (RSBI) to predict extubation success or failure.

OBJECTIVES

The aim of the study was to compare the new composite index named the rapid shallow diaphragmatic index (RSDI), and the RSBI measured during a spontaneous breathing trial regarding their ability to predict the need for re-intubation at 72 h.

METHODS

One hundred mechanically ventilated patients underwent daily 30-min spontaneous breathing trials (SBTs) under pressure support ventilation of 6 cm H₂O and end-expiratory pressure of 0 cm H₂O until the SBT was considered successful and followed by extubation. The performances of RSBI (respiratory rate/tidal volume) and of the ratio RSBI/DE measured at 5 and 25 min of the successful SBT were compared in terms of area under the receiver operating characteristics curve (AUC), for predicting extubation success at 72 h. As secondary analysis, extubation and weaning success at 7 d were also considered. As exploratory analyses, predictive indices incorporating both clinical characteristics, the DE, and ultrasound diaphragm thickening fraction (DTF) were investigated.

RESULTS

RSBI and RSBI/DE showed AUCs with 95% confidence intervals consistently extending below 0.50, either at the 5th (0.55 [0.36-0.74] and 0.55 [0.34-0.75], respectively) or at the 25th minute of SBT (0.49 [0.27-0.71] and 0.50 [0.29-0.68], respectively) for predicting weaning success at 72 h or at 7 d (5th min: 0.53 [0.37-0.70] and 0.54 [0.37-0.70], respectively; 25th min: 0.54 [0.37-0.71] and 0.55 [0.39-0.71], respectively). An exploratory index incorporating the accessory respiratory muscle activity, DE, DTF, and respiratory rate at 5th min of SBT showed AUCs for predicting extubation success at 7 d in the 78 patients with DTF measurement (0.77 [0.64-0.90]) that were significantly higher than that of the RSBI (P = 0.017) and RSBI/DE (P < 0.001) in the same respective populations.

CONCLUSIONS

The RSBI and the ratio RSBI/DE failed to predict weaning success when measured during an SBT performed under minimal pressure support. Predictive indices incorporating ultrasound DE and DTF may merit further investigation.

Could myocardial function be predictive of successful extubation in newborns and infants?

OBJECTIVE

To investigate the relationship between cardiac function and extubation readiness in infants using speckle tracking echocardiography.

WORKING HYPOTHESIS

Cardiac function combined with established clinical parameters may better identify readiness for extubation.

STUDY DESIGN

Pilot prospective observational study.

PATIENT SELECTION

Mechanically ventilated infants were included.

METHODOLOGY

Cardiac function was assessed by echocardiography immediately before extubation. Systolic and diastolic function in the left (LV) and right ventricles (RV) were assessed by measurement of longitudinal strain (LS), and circumferential strain (CS) in the LV only. Pulmonary artery pressures were assessed using the velocity of tricuspid regurgitation jet (TR), septal position, and end-systolic eccentricity index (EI ES). Cases who extubated successfully (Group 1) were compared to cases who required reintubation (Group 2).

RESULTS

Twenty-five cases were included. LV CS and RV LS were significantly lower in those who required reintubation (Group 2) compared to those who were successfully extubated (Group 1) (LV CS, -21 (12)% vs. -33 (3)%, p = .001; RV LS -19 (2.7)% vs. -20 (2.5)%, p = .04). TR was absent in all cases. The septal shape was normal in 18 cases (72%), displaced to the left in 7 (28%) cases. No significant differences were found in LV EI ES between groups.

Bedside noninvasive monitoring of mechanically ventilated patients

PURPOSE OF REVIEW

Among noninvasive lung imaging techniques that can be employed at the bedside electrical impedance tomography (EIT) and lung ultrasound (LUS) can provide dynamic, repeatable data on the distribution regional lung ventilation and response to therapeutic manoeuvres.In this review, we will provide an overview on the rationale, basic functioning and most common applications of EIT and Point of Care Ultrasound (PoCUS, mainly but not limited to LUS) in the management of mechanically ventilated patients.

RECENT FINDINGS

The use of EIT in clinical practice is supported by several studies demonstrating good correlation between impedance tomography data and other validated methods of assessing lung aeration during mechanical ventilation. Similarly, LUS also correlates with chest computed tomography in assessing lung aeration, its changes and several pathological conditions, with superiority over other techniques. Other PoCUS applications have shown to effectively complement the LUS ultrasound assessment of the mechanically ventilated patient.

SUMMARY

Bedside techniques - such as EIT and PoCUS - are becoming standards of the care for mechanically ventilated patients to monitor the changes in lung aeration, ventilation and perfusion in response to treatment and to assess weaning from mechanical ventilation.

Left Ventricular Diastolic Dysfunction in Pediatric Sepsis: Outcomes in a Single-Center Retrospective Cohort Study

OBJECTIVES

Left ventricular diastolic dysfunction is associated with difficulty in ventilator weaning and increased mortality in septic adults. We evaluated the association of left ventricular diastolic dysfunction with outcomes in a cohort of children with severe sepsis and septic shock.

DESIGN

Retrospective cohort study.

SETTING

Single-center noncardiac PICU.

PATIENTS

Age greater than 1 month to less than 18 years old with severe sepsis or septic shock from January 2011 to June 2017 with echocardiogram within 48 hours of sepsis onset.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Echocardiograms were retrospectively assessed for mitral inflow E (early) and A (atrial) velocity and e' (early mitral annular motion) septal and lateral velocity. Left ventricular diastolic dysfunction was defined as E/e' greater than 10, E/A less than 0.8, or E/A greater than 1.5. Left ventricular diastolic dysfunction was present in 109 of 204 patients (53%). The data did not demonstrate an association between the presence of left ventricular diastolic dysfunction and the proportion of children requiring invasive mechanical ventilation at the time of echocardiogram (difference in proportion, +5% [72% vs 67%; 95% CI, -8% to 17%]; p = 0.52). The duration of mechanical ventilation was median 192.9 hours (interquartile range, 65.0-378.4 hr) in the left ventricular diastolic dysfunction group versus 151.0 hours (interquartile range, 45.7-244.3 hr) in the group without left ventricular diastolic dysfunction. The presence of left ventricular diastolic dysfunction was not significantly associated with ICU length of stay or mortality. Exploratory analyses revealed that an alternative definition of left ventricular diastolic dysfunction, solely defined by E/e' greater than 10, was found to have an association with mechanical ventilation requirement at the time of echocardiogram (difference in proportion, +15%; 95% CI, 3-28%; p = 0.02) and duration of mechanical ventilation (median, 207.3 vs 146.9 hr).

CONCLUSIONS

The data failed to show an association between the presence of left ventricular diastolic dysfunction defined by both E/e' and E/A and the primary and secondary outcomes. When an alternative definition of left ventricular diastolic dysfunction with E/e' alone was used, there was a significant association with respiratory outcomes.

Recurrent Extubation Failure Following Neonatal Cardiac Surgery Is Associated with Increased Mortality

Extubation failure (EF) following neonatal cardiac surgery is associated with increased mortality. Neonates who experienced EF twice or more (recurrent EF) may have worse outcomes than those who have a single EF or no-EF. The aims of this study are to investigate the in hospital mortality for neonates with recurrent EF compared to those with single or no-EF, and determine factors associated with recurrent EF. Neonates' ≤ 28 days who underwent cardiac surgery from January 2008 to December 2019 were included. EF was defined as unplanned reintubation within 72 h after a planned extubation. 1187 (18 recurrent EF, 84 single EF and 1085 no-EF) neonates were included. Recurrent EF occurred in 18 (17.6%) of 102 neonates undergoing a second extubation. The median time (IQR) to reintubation after the first and second extubations were similar, being 20.9 (3.3-45.2) versus 19.4 (5.5-47) h. The reason for a second-time EF was respiratory in 39% and cardiovascular in 33%. Recurrent EF and single EF was associated with increased mortality (odds ratio, 95% confidence interval (CI) 23.5, 6.9-79.9) and (odds ratio, 95% CI 5.2, 2.3-12.0) compared to no-EF. Based on the final model with risk adjustment, predicted mortality was 29.0% in recurrent EF, 6.5% in single EF, and 1.2% in no-EF. First-time EF due to cardiovascular compromise was associated with recurrent EF (odds ratio, 95% CI 3.1, 1.0-9.7). This study confirmed that patients with recurrent EF have a high morality. Neonates with a cardiovascular reason for first-time EF are more likely to have a recurrent EF than those with other causes.

Prolonged Weaning: S2k Guideline Published by the German Respiratory Society

Mechanical ventilation (MV) is an essential part of modern intensive care medicine. MV is performed in patients with severe respiratory failure caused by respiratory muscle insufficiency and/or lung parenchymal disease; that is, when other treatments such as medication, oxygen administration, secretion management, continuous positive airway pressure (CPAP), or nasal high-flow therapy have failed. MV is required for maintaining gas exchange and allows more time to curatively treat the underlying cause of respiratory failure. In the majority of ventilated patients, liberation or "weaning" from MV is routine, without the occurrence of any major problems. However, approximately 20% of patients require ongoing MV, despite amelioration of the conditions that precipitated the need for it in the first place. Approximately 40-50% of the time spent on MV is required to liberate the patient from the ventilator, a process called "weaning". In addition to acute respiratory failure, numerous factors can influence the duration and success rate of the weaning process; these include age, comorbidities, and conditions and complications acquired during the ICU stay. According to international consensus, "prolonged weaning" is defined as the weaning process in patients who have failed at least 3 weaning attempts, or require more than 7 days of weaning after the first spontaneous breathing trial (SBT). Given that prolonged weaning is a complex process, an interdisciplinary approach is essential for it to be successful. In specialised weaning centres, approximately 50% of patients with initial weaning failure can be liberated from MV after prolonged weaning. However, the heterogeneity of patients undergoing prolonged weaning precludes the direct comparison of individual centres. Patients with persistent weaning failure either die during the weaning process, or are discharged back to their home or to a long-term care facility with ongoing MV. Urged by the growing importance of prolonged weaning, this Sk2 Guideline was first published in 2014 as an initiative of the German Respiratory Society (DGP), in conjunction with other scientific societies involved in prolonged weaning. The emergence of new research, clinical study findings and registry data, as well as the accumulation of experience in daily practice, have made the revision of this guideline necessary. The following topics are dealt with in the present guideline: Definitions, epidemiology, weaning categories, underlying pathophysiology, prevention of prolonged weaning, treatment strategies in prolonged weaning, the weaning unit, discharge from hospital on MV, and recommendations for end-of-life decisions. Special emphasis was placed on the following themes: (1) A new classification of patient sub-groups in prolonged weaning. (2) Important aspects of pulmonary rehabilitation and neurorehabilitation in prolonged weaning. (3) Infrastructure and process organisation in the care of patients in prolonged weaning based on a continuous treatment concept. (4) Changes in therapeutic goals and communication with relatives. Aspects of paediatric weaning are addressed separately within individual chapters. The main aim of the revised guideline was to summarize both current evidence and expert-based knowledge on the topic of "prolonged weaning", and to use this information as a foundation for formulating recommendations related to "prolonged weaning", not only in acute medicine but also in the field of chronic intensive care medicine. The following professionals served as important addressees for this guideline: intensivists, pulmonary medicine specialists, anaesthesiologists, internists, cardiologists, surgeons, neurologists, paediatricians, geriatricians, palliative care clinicians, rehabilitation physicians, intensive/chronic care nurses, physiotherapists, respiratory therapists, speech therapists, medical service of health insurance, and associated ventilator manufacturers.

Biological Context Linking Hypertension and Higher Risk for COVID-19 Severity

The coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), represents a public health crisis of major proportions. Advanced age, male gender, and the presence of comorbidities have emerged as risk factors for severe illness or death from COVID-19 in observation studies. Hypertension is one of the most common comorbidities in patients with COVID-19. Indeed, hypertension has been shown to be associated with increased risk for mortality, acute respiratory distress syndrome, need for intensive care unit admission, and disease progression in COVID-19 patients. However, up to the present time, the precise mechanisms of how hypertension may lead to the more severe manifestations of disease in patients with COVID-19 remains unknown. This review aims to present the biological plausibility linking hypertension and higher risk for COVID-19 severity. Emphasis is given to the role of the renin-angiotensin system and its inhibitors, given the crucial role that this system plays in both viral transmissibility and the pathophysiology of arterial hypertension. We also describe the importance of the immune system, which is dysregulated in hypertension and SARS-CoV-2 infection, and the potential involvement of the multifunctional enzyme dipeptidyl peptidase 4 (DPP4), that, in addition to the angiotensin-converting enzyme 2 (ACE2), may contribute to the SARS-CoV-2 entrance into target cells. The role of hemodynamic changes in hypertension that might aggravate myocardial injury in the setting of COVID-19, including endothelial dysfunction, arterial stiffness, and left ventricle hypertrophy, are also discussed.

Does Intraoperative Diuretic Therapy Affect the Thoracic Fluid Content and Clinical Outcome in Patients Undergoing Mitral Valve Surgery?

Pulmonary congestion is inevitable in valvular heart disease. The condition worsens when a patient undergoes cardiopulmonary bypass (CPB). Thoracic fluid content (TFC) is an indicator of total volume status of lung in health and disease. We hypothesize that intraoperative diuretic therapy can improve the hemodynamic and clinical outcome in patients undergoing mitral valve surgery by decreasing TFC as measured by impedance cardiography (ICG).

Sixty adult patients with critical mitral stenosis scheduled for mitral valve surgery divided into diuretic (Gr D, n = 30) and control (Gr C, n = 30) group. One mg/kg of furosemide was administered before CPB to Gr D and similar volume of normal saline to Gr C. Hemodynamic and TFC measurements were done by index of contractility (ICON), NICOM monitor at baseline, before anesthesia induction (T1), post skin closure (T2), postoperatively at 6th hour (T3), 24th hour (T4), and 48th hour (T5). The duration of mechanical ventilation (hour), intensive care unit stay (day) and inotropic score was significantly higher in Gr C (5.29 ± 1.4 vs. 2.15 ± 1.1; p = 0.001; 2.11 ± 0.64 vs. 1.67 ± 0.57, p = 0.002; 9 ± 5.4 vs. 5.8 ± 3.2, p = 0.05), respectively. Three patients in Gr C developed respiratory complication during their course of hospital stay. The baseline TFC value was comparable (p = 0.08). In Gr C. it gradually increased over time and never reached the baseline value, whereas in Gr D, there was slight increase in TFC till 6th postoperative hour and it came below the baseline value at 48th hour. A significantly higher TFC value in Gr C in comparison with Gr D from 6th to 48th postoperative hour (p = 0.005, 0.000, and 0.005, respectively) was observed.

The ICON had a gradual improvement from 12th over 48th postoperative hour in Gr D in comparison to Gr C. The systemic vascular resistance index was decreased over time in Gr C, whereas in Gr D there was a mild fall at the end of surgery and it came back to near the baseline value at 48th postoperative hour. A continuous decrease in DO2 I except at 6th postoperative hour was seen in Gr C, whereas it remained near the baseline value in Gr D.

Linear regression analysis showed significant direct correlation of TFC with intraoperative fluid balance (r = 0.524, p = 0.001), cumulative fluid balance (r = 0.680, p = 0.000) and both peak and mean airway pressure (r = 0.436, p = 0.001 and r = 0.548, p = 0.001, respectively).

We concluded that TFC is clearly influenced by intraoperative diuretic therapy. A decrease in TFC has an association with better hemodynamic parameters that could find interesting clinical applications in the decision, whether or not to include a diuretic as a routine therapy during intraoperative management in valve surgery patients.

Association of weaning failure from mechanical ventilation with transthoracic echocardiography parameters: a systematic review and meta-analysis

BACKGROUND

Weaning from mechanical ventilation is a challenging step during recovery from critical illness. Weaning failure or early reintubation are associated with increased morbidity and mortality, exposing patients to life-threatening complications. Cardiac dysfunction represents the most common cause of weaning failure. We conducted a systematic review and meta-analysis to evaluate the association between transthoracic echocardiographic parameters and weaning failure.

METHODS

We performed a systematic search of MEDLINE and EMBASE screening for prospective studies providing echocardiographic data collected just before the beginning of spontaneous breathing trial and outcome of the weaning attempt. We primarily focused on parameters currently recommended for evaluation of left ventricular (LV) systolic or diastolic dysfunction.

RESULTS

We included 11 studies in our primary analysis, which included data on LV ejection fraction (LVEF, n=10 studies) and parameters recommended for the assessment of LV diastolic function (E/e' ratio n=10; E/A ratio n=9; E wave n=8; and e' wave n=7). Weaning failure was significantly associated to a higher E/e' ratio (standardised mean difference [SMD]=1.70, 95% confidence interval [CI; 0.78-2.62]; P<0.001), lower e' wave (SMD=-1.22, 95% CI [-2.33 to -0.11]; P=0.03), and higher E wave (SMD=0.97, 95% CI [0.29-1.65]; P=0.005). We found no association between weaning failure and LVEF (SMD=-0.86, 95% CI [-1.92-0.20]; P=0.11) and E/A ratio (SMD=0.00, 95% CI [-0.30-0.31]; P=0.98).

CONCLUSIONS

Weaning failure is associated with parameters indicating worse LV diastolic function (E/e', e' wave, E wave) and increased LV filling pressure (E/e' ratio). The association between weaning failure and LV systolic dysfunction as evaluated by LVEF is more unclear. More studies are needed to clarify this aspect and regarding the role of right ventricular function.

Thoracic fluid content: a novel parameter for predicting failed weaning from mechanical ventilation

Background

Weaning of patients from the mechanical ventilation remains one of the critical decisions in intensive care unit. This study aimed to evaluate the accuracy of thoracic fluid content (TFC) as a predictor of weaning outcome.

Methods

An observational cohort study included 64 critically ill surgical patients who were eligible for extubation. Before initiating the spontaneous breathing trial, the TFC was measured using the electrical cardiometry technology. Patients were followed up after extubation and divided into successful weaning group and failed weaning group. Both groups were compared according to respiratory and cardiovascular parameters. Receiver operating characteristic (ROC) curves were constructed to evaluate the ability of TFC to predict weaning outcome.

Results

The number of successfully weaned patients was 41/64 (64%). Twenty (31%) patients had impaired cardiac contractility, and of them, 13/20 (64%) patients were successfully extubated. Both groups, successful weaning group and failed weaning group, were comparable in most of baseline characteristics; however, the TFC was significantly higher in the failed weaning group compared to the successful weaning group. The area under the ROC curves (AUCs) showed moderate predictive ability for the TFC in predicting weaning failure (AUC [95% confidence interval] 0.69 [0.57-0.8], cutoff value > 50 kΩ^-1), while the predictive ability of TFC was excellent in the subgroup of patients with ejection fraction < 40% (AUC [95% confidence interval 0.93 [0.72-1], cutoff value > 50 kΩ^-1).

Conclusions

Thoracic fluid content showed moderate ability for predicting weaning outcome in surgical critically ill patients. However, in the subgroup of patients with ejection fraction less than 40%, TFC above 50 kΩ^-1 has an excellent ability to predict weaning failure.

Diastolic dysfunction of the left ventricle - a practical approach for an anaesthetist

Bedside point-of-care echocardiography is being increasingly incorporated in peri-operative assessment and in intensive care units. Because of availability of tissue Doppler imaging in the modern ultrasound machines there has been an increased interest in research of diastolic function of left ventricle. The diastolic function is crucial for the hemodynamically effective function of the heart. Diastolic dysfunction is a well-established risk factor of the major adverse cardiac events during perioperative period, complications during weaning from ventilator and prognostic factor of mortality in septic shock.

Evaluation of the association between decreased skeletal muscle mass and extubation failure after long-term mechanical ventilation

BACKGROUND & AIMS

Elderly patients are being increasingly admitted to the intensive care unit (ICU) for mechanical ventilation (MV) and prevalence of decreased skeletal muscle mass which develop with aging is subsequently increasing. The objective of this study was to identify the association between decreased skeletal muscle mass and extubation failure in patients undergoing long-term MV.

METHODS

Adults (≥18 years of age) with long-term MV for > 7 days between January 2014 and February 2019 were included retrospectively. Patients who died or were transferred with MV, underwent tracheostomy with failure of weaning from MV, and had not undergone abdominal computed tomography within 3 days before or after intubation were excluded. Failed extubation was defined as reintubation within 48 h after extubation following long-term MV for >7 days. We divided the patients into extubation success and failure groups.

RESULTS

Parameters including patients' demographics, cause of intubation, initial setting of MV, maximum inspiratory pressure (MIP) and rapid shallow breath index (RSBI) at extubation, and skeletal muscle mass were compared between the two groups. Decreased skeletal muscle mass was set a standard as a L3 muscle index of less than 49 cm²/m² for men and of less than 31 cm²/m² for women using Korean-specific cut-offs for sarcopenia as evaluated on previous epidemiologic study. Among 104 patients who were screened, 45 were included, and 11 (24.4%) failed to be extubated. Mean MIP (23.5 ± 11.8 vs. 32.4 ± 9.3, p = 0.134) and RSBI (57.2 ± 26.5 vs. 55.3 ± 20.4, p = 0.803) were not different between the two groups. The proportions of patients whose MIP or RSBI satisfied the cutoff for extubation were not different between the groups. There were no significant differences in age, sex, body mass index, comorbidities, nutritional status, and cause of intubation between the two groups. The extubation failure group showed a higher proportion of decreased skeletal muscle mass (90.9% vs. 58.8%, p = 0.05) and longer duration of MV (10.7 ± 4.1 vs. 9.6 ± 3.4, p < 0.001) than the extubation success group. Multivariate analysis showed that the duration of intubation (OR = 1.439, 95% CI = 1.12-1.85), and decreased skeletal muscle mass (OR = 24.382, 95% CI = 1.00-594.86) were associated with extubation failure.

CONCLUSIONS

Decreased skeletal muscle mass was associated with extubation failure after long-term MV for > 7 days. It is important to diagnose decreased skeletal muscle mass in critically ill patients to reduce extubation failure rates.

Myocardial ischemia during ventilator weaning: a prospective multicenter cohort study

BACKGROUND

Weaning-induced cardiac pulmonary edema (WiPO) is one of the main mechanisms of weaning failure during mechanical ventilation. We hypothesized that weaning-induced cardiac ischemia (WiCI) may contribute to weaning failure from cardiac origin.

METHODS

A prospective cohort study of patients mechanically ventilated for at least 24 h who failed a first spontaneous breathing trial (SBT) was conducted in four intensive care units. Patients were explored during a second SBT using multiple tools (echocardiography, continuous 12-lead ST monitoring, biomarkers) to scrutinize the mechanisms of weaning failure. WiPO definition was based on three criteria (echocardiographic signs of increased left atrial pressure, increase in B-type natriuretic peptides, or increase in protein concentration during SBT) according to a conservative definition (at least two criteria) and a liberal definition (at least one criterion). WiCI was diagnosed according to the third universal definition of myocardial infarction proposed by the European Society of Cardiology (ESC) and the American Heart Association (AHA) statement for exercise testing.

RESULTS

Among patients who failed a first SBT, WiPO occurred in 124/208 (59.6%) and 44/208 (21.2%) patients, according to the liberal and conservative definition, respectively. Among patients with ST monitoring, WiCI was diagnosed in 36/177 (20.3%) and 12/177 (6.8%) of them, according to the ESC and AHA definitions, respectively. WiCI was not associated with WiPO and was not associated with weaning outcomes. Only two patients of the cohort were treated for an acute coronary syndrome after the second SBT, and seven other patients required coronary angiography during the weaning period.

CONCLUSIONS

This observational study showed the common occurrence of pulmonary edema in mechanically ventilated patients who failed a first SBT, but the association with cardiac ischemia and weaning outcomes was weak.

Contribution of Levosimendan in Weaning from Mechanical Ventilation in Patients with Left Ventricular Dysfunction: A Pilot Study

Purpose

Mechanically ventilated patients with left ventricular (LV) dysfunction are at risk of weaning failure. We hypothesized that optimization of cardiovascular function might facilitate the weaning process. Therefore, we investigated the efficacy of levosimendan in difficult-to-wean patients with impaired LV performance.

Materials and Methods

Nineteen mechanically ventilated patients, with LV ejection fraction (LVEF) 34 ± 8%, difficult-to-wean from the ventilator, were assessed by transthoracic echocardiography before the start and at the end of a spontaneous breathing trial (SBT) (first SBT). Eight patients successfully weaned. The remaining 11 failed-to-wean patients received a 24-hour infusion of levosimendan, and they were reassessed during a second SBT.

Results

After levosimendan administration, LVEF increased from 30 ± 10 to 36 ± 3% (p=0.01). End-SBT peak e′ velocity increased from 7 to 9 cm/s (p=0.02). E/e′ increased from 10.5 to 12.9 during the first SBT, whereas it remained constant at 10 throughout the second SBT (p=0.01). During the second SBT, partial pressure of arterial oxygen and central venous oxygen saturation improved, compared to the first one (93 ± 34 vs. 67 ± 28 mmHg, p=0.03, and 66 ± 11% vs. 57 ± 9%, p=0.02, respectively). Nine of the 11 patients were successfully weaned from the ventilator.

Conclusions

In difficult-to-wean from mechanical ventilation patients with LV dysfunction, levosimendan might contribute to successful weaning by improving both systolic and diastolic LV function.

Pulmonary Ultrasound: A New Era in Critical Care Medicine

Pulmonary ultrasonography is a complementary study that is easy to perform at the patient bedside with no need to transfer the patient to special areas. The technique provides information with high sensitivity and specificity for different pathologies. Pulmonary ultrasonography is a very important diagnostic tool in the assessment of lung, pleural, and chest wall diseases. Pulmonary ultrasound provides low-cost analysis, easy real-time reproduction, and safety, all of which have made it a beneficial tool in the diagnostic arsenal available to medical personnel. The purpose of this review was to describe the usefulness of pulmonary ultrasound in critical areas.

A simplified definition of diastolic function in sepsis, compared against standard definitions

Background

Guidelines for grading diastolic dysfunction poorly categorize septic patients. We compared how well the American Society of Echocardiography (ASE) 2009 and 2016 definitions and a simplified definition categorized septic patients.

Methods

We studied septic patients who received a transthoracic echocardiogram within 24 h of admission to an ICU. We categorized patients according to ASE 2009 and 2016 definitions and a definition using E/e’, a surrogate for left ventricular filling pressure. We assessed 28-day all-cause mortality and the presence of pre-existing diabetes, hypertension, or myocardial infarction. We tested for associations among diastolic grade, comorbidities, and outcomes using logistic regression.

Results

We studied 398 patients. Mortality was 23%. The simplified definition categorized more patients than ASE 2016 (78% vs. 71%, p = 0.035); both definitions categorized more patients than ASE 2009 (34%, p < 0.001 for both comparisons). Higher grades of diastolic dysfunction were associated with hypertension (ASE 2016, simplified), myocardial infarction (ASE 2009, simplified), and diabetes (simplified). Grade of diastolic dysfunction was not associated with mortality by any definition. Of 199 patients categorized as normal by ASE 2016, 40% had an abnormal E/e′ > 9 and 7% had a severely abnormal E/e′ > 13.

Conclusions

The ASE 2016 definition categorizes more septic patients than the ASE 2009 definition, but it does not categorize the diastolic function of a third of septic patients. ASE 2016 designates many patients with elevated E/e′ as normal. A simplified definition categorized patients with less ambiguity and is associated with relevant comorbidities.

Electronic supplementary material

The online version of this article (10.1186/s40560-019-0367-3) contains supplementary material, which is available to authorized users.

Weaning failure of cardiovascular origin: how to suspect, detect and treat-a review of the literature

Among the multiple causes of weaning failure from mechanical ventilation, cardiovascular dysfunction is increasingly recognized as a quite frequent cause that can be treated successfully. In this review, we summarize the contemporary evidence of the most important clinical and diagnostic aspects of weaning failure of cardiovascular origin with special focus on treatment. Pathophysiological mechanisms are complex and mainly include increase in right and left ventricular preload and afterload and potentially induce myocardial ischemia. Patients at risk include those with preexisting cardiopulmonary disease either known or suspected. Clinically, cardiovascular etiology as a predominant cause or a contributor to weaning failure, though critical for early diagnosis and intervention, may be difficult to be recognized and distinguished from noncardiac causes suggesting the need of high suspicion. A cardiovascular diagnostic workup including bedside echocardiography, lung ultrasound, electrocardiogram and biomarkers of cardiovascular dysfunction or other adjunct techniques and, in selected cases, right heart catheterization and/or coronary angiography, should be obtained to confirm the diagnosis. Official clinical practice guidelines that address treatment of a confirmed weaning-induced cardiovascular dysfunction do not exist. As the etiologies of weaning-induced cardiovascular dysfunction are diverse, principles of management depend on the individual pathophysiological mechanisms, including preload optimization by fluid removal, guided by B-type natriuretic peptide measurement, nitrates administration in excessive afterload and/or myocardial ischemia, contractility improvement in severe systolic dysfunction as well as other rational treatment in specific indications in order to lead to successful weaning from mechanical ventilation.

Prospective Observational Study on Evaluation of Cardiac Dysfunction Induced during the Weaning Process

Context

Weaning induced cardiac dysfunction can occur without underlying heart disease. Changes in intrathoracic pressure, systemic vascular resistance, preload and afterload leading to heart-lung interactions are the possible explanatory mechanisms

Aims

The aim of the current study was whether the assessment and identification of cardiac dysfunction induced during the weaning process could predict the outcome of extubation.

Settings and design

A prospective observational study with convenience sampling method was conducted from May 2015 to April 2016 after institutional ethical committee approval (ref 161/2015).

Materials and methods

Patients over eighteen and planned for extubation were included. Weaning method used was a spontaneous breathing trial (SBT) by pressure support-positive end-expiratory pressure (PS-PEEP). Baseline characteristics, weaning, and echocardiography parameters were collected pre extubation. Post-extubation echocardiographic parameters were collected within six hours as per the protocol. The primary outcome was extubation failure (reintubation within 48 hours). Secondary outcomes were ICU length of stay and ICU mortality.

Statistical analysis

Statistical method used is STATA™ (Version14, College Station TX).

Results

Out of one hundred and sixty-one patients, twenty-one failed extubation (13.04 %). Pre-extubation echocardiographic parameters were similar in two groups except for preexisting LV systolic dysfunction. Post-extubation E/e` (9.30 vs. 7.71 p = 0.018) was higher in the extubation failure group. Extubation failure group had higher intensive care unit (ICU) length of stay and ICU mortality.

Conclusion

In our study E/e` during a weaning trial did not predict extubation success. Cardiac dysfunction induced during weaning may get masked during weaning and manifests postextubation. This needs to be verified in subsequent studies.

Key messages

Cardiac dysfunction induced during the weaning process may get masked and manifests post-extubation. Echocardiographic assessment during the weaning process and post-extubation helps to evaluate and identify the patients at risk of reintubation.

How to cite this article

Amarja H, Bhuvana K, Sriram S. Prospective Observational Study on Evaluation of Cardiac Dysfunction Induced during the Weaning Process. Indian Journal of Critical Care Medicine, January 2019;23(1):15-19.

Non-invasive hemodynamic evaluation by Doppler echocardiography

The approach for treating a hemodynamically unstable patient remains a diagnostic and therapeutic challenge. Stabilization of the patient should be rapid and effective, but there is not much room for error. This narrow window of intervention makes it necessary to use rapid and accurate hemodynamic evaluation methods. Echocardiography is the method of choice for the bedside evaluation of patients in circulatory shock. In fact, it was intensive care physicians who recognized the potential of Doppler echocardiography for the initial approach to patients in circulatory failure. An echocardiogram allows rapid anatomical and functional cardiac evaluation, which may include non-invasive hemodynamic evaluation using a Doppler study. Such an integrated study may provide data of extreme importance for understanding the mechanisms underlying the hemodynamic instability of the patient to allow the rapid institution of appropriate therapeutic measures. In the present article, we describe the most relevant echocardiographic findings using a practical approach for critical patients with hemodynamic instability.

Practical approach to diastolic dysfunction in light of the new guidelines and clinical applications in the operating room and in the intensive care

There is growing evidence both in the perioperative period and in the field of intensive care (ICU) on the association between left ventricular diastolic dysfunction (LVDD) and worse outcomes in patients. The recent American Society of Echocardiography and European Association of Cardiovascular Imaging joint recommendations have tried to simplify the diagnosis and the grading of LVDD. However, both an often unknown pre-morbid LV diastolic function and the presence of several confounders-i.e., use of vasopressors, positive pressure ventilation, volume loading-make the proposed parameters difficult to interpret, especially in the ICU. Among the proposed parameters for diagnosis and grading of LVDD, the two tissue Doppler imaging-derived variables e' and E/e' seem most reliable. However, these are not devoid of limitations. In the present review, we aim at rationalizing the applicability of the recent recommendations to the perioperative and ICU areas, discussing the clinical meaning and echocardiographic findings of different grades of LVDD, describing the impact of LVDD on patients' outcomes and providing some hints on the management of patients with LVDD.

Ultrasound assessment of diaphragmatic dysfunction as a predictor of weaning outcome from mechanical ventilation: a systematic review and meta-analysis

OBJECTIVE

The aim of this systematic review was to assess the diaphragmatic dysfunction (DD) as a predictor of weaning outcome.

BACKGROUND

Successful weaning depends on several factors: muscle strength, cardiac, respiratory and metabolic. Acquired weakness in mechanical ventilation is a growing important cause of weaning failure. With the development of ultrasonography, DD can be evaluated with ultrasound in weakness patients to predict weaning outcomes.

METHODS

The Cochrane Library, PubMed, Embase, Ovid Medline, WanFang Data and CNKI were systematically searched from the inception to September 2017. Ultrasound assessment of DD in adult mechanical ventilation patients was included. Two independent investigators assessed study quality in accordance with the Quality Assessment of Diagnostic Accuracy Studies-2 tool. The primary outcome was diaphragmatic thickness and excursion in the weaning success and failure group. The secondary outcome was the influence of DD on weaning outcome.

RESULTS

Eleven studies involving a total of 436 patients were included. There were eight studies comparing diaphragmatic excursion (DE), five comparing the diaphragmatic thickening fraction (DTF) and two comparing DD between groups with and without successful weaning. Overall, the DE or DTF had a pooled sensitivity of 0.85 (95% CI 0.77 to 0.91) and a pooled specificity of 0.74 (95% CI 0.66 to 0.80) for predicting weaning success. There was high heterogeneity among the included studies (I²=80%; p=0.0006). The rate of weaning failure was significantly increased in patients with DD (OR 8.82; 95% CI 3.51 to 22.13; p<0.00001).

CONCLUSIONS

Both DE and DTF showed good diagnostic performance to predict weaning outcomes in spite of limitations included high heterogeneity among the studies. DD was found to be a predictor of weaning failure in critically ill patients.

Cardiovascular failure and weaning

Cardiac patients are at high risk of weaning failure due to the abrupt burden to the cardiovascular system resulting from the transition from positive-pressure ventilation to spontaneous breathing. Similarly, numerous patients with borderline cardiac function, left ventricular diastolic dysfunction, chronic obstructive pulmonary disease, especially with associated fluid overload or cumulative positive fluid balance, are at high risk of weaning failure of cardiac origin. The diagnosis of weaning-induced pulmonary oedema (WiPO) relies on the measurement of elevated left ventricular filling pressure, or on the presence of a surrogate reflecting pulmonary or cardiac congestion. Plasma concentration of B-type natriuretic peptide and N-terminal proBNP, biological signs of hemoconcentration (increased circulating protein or hemoglobin levels), or measurement of extravascular pulmonary lung water using transpulmonary thermodilution have been proved valuable surrogates for the identification of weaning failure. Nevertheless, studies have not yet compared these indirect methods to precisely determine their respective diagnostic values for the identification of WiPO, especially in heart failure patients. In addition, none of these approaches directly assess left ventricular filling pressure and the mechanism of WiPO. In contrast, critical care echocardiography is ideally suited to establish the diagnosis of weaning failure of cardiac origin. It allows identifying the high-risk population, monitoring hemodynamically the patient at risk, depicting an abrupt increase of left ventricular filling pressure consistent with WiPO when the patient fails weaning, identifying the underlying mechanism of WiPO, and finally it allows tailoring the therapeutic management of the patient who failed weaning. The impact on patient-centered outcomes of such integrated management strategy based on critical care echocardiography deserves to be prospectively tested in a large population of patients at high risk of weaning failure of cardiac origin.

Predictive factors of weaning from mechanical ventilation and extubation outcome: A systematic review

PURPOSE

To identify, describe and discuss the parameters used to predict weaning from mechanical ventilation and extubation outcomes.

METHODS

Systematic review of scientific articles using four electronic databases: PubMed, Embase, PEDro and Cochrane Library. Search terms included "weaning", "extubation", "withdrawal" and "discontinuation", combined with "mechanical ventilation" and "predictive factors", "predictive parameters" and "predictors for success". In this study, we included original articles that presented predictive factors for weaning or extubation outcomes in adult patients and not restricted to a single disease. Articles not written in English were excluded.

RESULTS

A total of 43 articles were included, with a total of 7929 patients and 56 different parameters related to weaning and extubation outcomes. Rapid Shallow Breathing Index (RSBI) was the most common predictor, discussed in 15 studies (2159 patients), followed by Age and Maximum Inspiratory Pressure in seven studies. The other 53 parameters were found in less than six studies.

CONCLUSION

There are several parameters used to predict weaning and extubation outcomes. RSBI was the most frequently studied and seems to be an important measurement tool in deciding whether to wean/extubate a patient. Furthermore, the results demonstrated that weaning and extubation should be guided by several parameters, and not only to respiratory ones.

The impact of heart, lung and diaphragmatic ultrasound on prediction of failed extubation from mechanical ventilation in critically ill patients: a prospective observational pilot study

Background

Failed extubation from mechanical ventilation in critically ill patients is multifactorial, complex and not well understood. We aimed to identify whether combined transthoracic echocardiography, lung and diaphragmatic ultrasound can predict extubation failure in critically ill patients.

Results

Fifty-three participants who were intubated > 48 h and deemed by the treating intensivist ready for extubation underwent a 60-min pre-extubation weaning trial (pressure support ≤ 10 cmH₂O and positive end expiratory pressure 5 cmH₂O). Prior to extubation, data collected included ultrasound assessment of left ventricular ejection fraction, left atrial area, early diastolic trans-mitral flow velocity wave (E), early diastolic trans-mitral flow velocity wave/late diastolic trans-mitral flow velocity wave (E/A), early diastolic trans-mitral flow velocity wave/early diastolic mitral annulus velocity (E/E′), interatrial septal motion, lung loss of aeration score and diaphragm movement. At the end of the weaning trial, the rapid shallow breathing index and serum B-type natriuretic peptide concentration were measured. Success and failure of weaning was assessed by defined criteria. Decision to extubate was at the discretion of the treating intensivist. Failure of extubation was defined as re-intubation, non-invasive ventilation or death within 48 h after extubation. Of 53 extubated participants, 11 failed extubation. Failed extubation was associated with diabetes, ischaemic heart disease, higher E/E′ (OR 1.27, 95% CI 1.05–1.54), left atrial area (OR 1.14, CI 1.02–1.28), fixed rightward curvature of the interatrial septum (OR 12.95, CI 2.73–61.41), and higher loss of aeration score of anterior and lateral regions of the lungs (OR 1.41, CI 1.01–1.82).

Conclusions

Failed extubation in mechanically ventilated patients is more prevalent if markers of left ventricular diastolic dysfunction and loss of lung aeration are present.

Preliminary Exploration of Epidemiologic and Hemodynamic Characteristics of Restrictive Filling Diastolic Dysfunction Based on Echocardiography in Critically Ill Patients: A Retrospective Study

Objective

To preliminarily describe the epidemiologic and hemodynamic characteristics of critically ill patients with restrictive filling diastolic dysfunction based on echocardiography.

Setting

A retrospective study.

Methods

Epidemiologic characteristics of patients with restrictive filling diastolic dysfunction in ICU were described; clinical and hemodynamic data were preliminarily summarized and compared between patients with and without restrictive filling diastolic dysfunction; most of the data were based on echocardiography.

Results

More than half of the patients in ICU had diastolic dysfunction and about 16% of them had restrictive filling pattern. The patients who had restrictive filling diastolic dysfunction were more likely to have wider diameter of IVC (2.18 ± 0.50 versus 1.92 ± 0.43, P = 0.037), higher extravascular lung water score (15.9 ± 9.2 versus 13.2 ± 9.1, P = 0.014), lower left ventricular ejection fraction (EF-S: 53.0 ± 16.3 versus 59.3 ± 12.5, P = 0.014), and lower percentage of normal LAP that was estimated by E/e′ (8.9% versus 90.0%, P = 0.001) when compared with those of patients without restrictive filling diastolic dysfunction.

Conclusion

Our results suggest that critically ill patients with restrictive filling diastolic dysfunction may experience rising volume status, increasing extravascular lung water ultrasonic score, reducing long-axis systolic dysfunction, and less possibility of normal left atrial pressure. Intensivists are advised to pay more attention to patients with diastolic dysfunction, especially the exquisite fluid management of patients with restrictive filling pattern due to the close relationship of restrictive filling diastolic dysfunction with volume status and extravascular lung water in our study.

Cardiac function during weaning failure: the role of diastolic dysfunction

Background

Cardiac dysfunction is a common cause of weaning failure. Weaning shares some similarities with a cardiac stress test and may challenge active phases of the cardiac cycle-like ventricular contractility and relaxation. This study aimed at assessing systolic and diastolic function during the weaning process and scrutinizing their dynamics during weaning trials.

Methods

Echocardiography was performed during baseline ventilator settings to assess cardiac function at the initiation of the weaning process and at the start and the end of consecutive weaning trials (performed at day-1, day-2, and before extubation if applicable) to explore the evolution of left ventricle contractility and relaxation in a subset of patients.

Results

Among 67 patients included, weaning was prolonged (≥ 7 days) in 18 (27%) patients and short (< 7 days) in 49 (73%). Prevalence of systolic dysfunction and isolated diastolic dysfunction before the initiation of weaning process were 37 and 17%, respectively. Isolated diastolic dysfunction was more frequent in patients with prolonged weaning as compared to their counterparts. Thirty-one patients were explored by echocardiography during consecutive weaning trials. An increase in filling pressures with an alteration of ventricular relaxation (as assessed by a decrease in tissue Doppler early mitral diastolic wave velocity) was found during failed weaning trials.

Conclusions

Isolated diastolic dysfunction was associated with a prolongation of weaning. Increased filling pressures with left ventricle relaxation impairment may be a key mechanism of weaning trial failure.

Electronic supplementary material

The online version of this article (10.1186/s13613-017-0348-4) contains supplementary material, which is available to authorized users.

Different effects of cardiac and diaphragm function assessed by ultrasound on extubation outcomes in difficult-to-wean patients: a cohort study

Background

Ultrasound is a convenient tool to evaluate cardiac and diaphragm function. The ratio (E/Ea) of mitral Doppler inflow velocity to annular tissue Doppler wave velocity by transthoracic echocardiography (TTE) and diaphragmatic excursion (DE) by diaphragm ultrasound have been confirmed in predicting extubation outcomes independently, however their different roles in the weaning process have not been determined until now.

Methods

We designed a cohort study to preform diaphragm ultrasound and TTE before and after the spontaneous breathing trial (SBT) in difficult-to-wean patients. Patients considered for enrollment should succeed on a SBT and have been extubated. They were followed up with the events of respiratory failure within 48 h, and divided into the respiratory failure and extubation success subgroups. Relevant risk factors predicting respiratory failure were analysed by a multivariate logistic regression model. Then, each subgroup was assessed with respect to re-intubation within 1 week, and divided into the re-intubation and non-intubation subgroups. Furthermore, relevant risk factors predicting re-intubation were also analysed in each subgroup. The area under the curve (AUC) and optimum cut-off value were identified by the receiver operating characteristic curve.

Results

Among 60 patients, 29 cases developed respiratory failure within 48 h, and 14 cases were re-intubated or died within 1 week, respectively. Multivariate logistic regression analysis showed that E/Ea (average) after SBT [odds ratio (OR) 1.450, 95% confidence intervals (CI) 1.092-1.926, P = 0.01] and left ventricular ejection fraction were associated with respiratory failure. The AUC of E/Ea (average) after SBT was 0.789, and a cut-off value ≥ 12.5 showed the highest diagnostic accuracy with a sensitivity and specificity of 72.4% and 77.4%, respectively. Furthermore, in the respiratory failure subgroup only DE (average) after SBT was associated with re-intubation (OR 0.690, CI 0.499-0.953, P = 0.024). The AUC of DE (average) after SBT was 0.805, and a cut-off value ≤ 12.6 mm showed the highest diagnostic accuracy with a sensitivity and specificity of 80% and 68.4%, respectively.

Conclusions

E/Ea (average) after SBT could help predict respiratory failure within 48 h. However, DE (average) after SBT could help predict re-intubation within 1 week in the respiratory failure subgroup.

Electronic supplementary material

The online version of this article (10.1186/s12890-017-0501-8) contains supplementary material, which is available to authorized users.