Diaphragmatic Dynamics and Thickness Parameters Assessed by Ultrasonography Predict Extubation Success in Critically Ill Patients

The Impact of Interscalene Brachial Plexus Block with Different Concentrations of Ropivacaine on Diaphragmatic Paralysis: A Randomized Controlled Study

Background

This study aims to evaluate the degree of diaphragmatic paralysis by assessing diaphragmatic excursion and pulmonary function following an ultrasound-guided interscalene brachial plexus block with two different concentrations of ropivacaine (0.2% and 0.5%).

Methods

Forty patients undergoing shoulder arthroscopic surgery were randomly assigned to receive ultrasound-guided interscalene brachial plexus block with 20 mL of either 0.2% or 0.5% ropivacaine. Diaphragmatic excursion (DE) and diaphragm thickening fraction (TF) were measured using M-mode ultrasound before and 30 minutes after the block. Pulmonary function was assessed using a portable spirometer. Additional outcomes included pain scores and the occurrence of adverse effects.

Results

DE was significantly reduced 30 minutes after block in the 0.5% group compared to the 0.2% group (p<0.01), as well as the TF (p<0.01). Forced vital capacity (FVC) was also significantly reduced in the 0.5% group 30 minutes after block in the preparation room compared to the 0.2% group (p<0.001). Both 0.2% and 0.5% ropivacaine had similar effects in improving postoperative pain. There were no serious block-related complications in either group.

Conclusion

0.2% ropivacaine may impair pulmonary function less than 0.5% ropivacaine. The clinical significance of these differences requires further investigation.

Predictors of weaning failure in ventilated intensive care patients: a systematic evidence map

BACKGROUND

Ventilator weaning is of great importance for intensive care patients in order to avoid complications caused by prolonged ventilation. However, not all patients succeed in weaning immediately. Their spontaneous breathing may be insufficient, resulting in extubation failure and the subsequent need for reintubation. To identify patients at high risk for weaning failure, a variety of potential predictors has already been examined in individual studies and meta-analyses over the last decades. However, an overview of all the predictors investigated is missing.

AIM

To provide an overview of empirically investigated predictors for weaning failure.

METHODS

A systematic evidence map was developed. To this end, we conducted a systematic search in the Medline, Cochrane, and CINAHL databases in December 2023 and added a citation search and a manual search in June 2024. Studies on predictors for weaning failure in adults ventilated in the intensive care unit were included. Studies on children, outpatients, non-invasive ventilation, or explanatory factors of weaning failure were excluded. Two reviewers performed the screening and data extraction independently. Data synthesis followed an inductive approach in which the predictors were thematically analyzed, sorted, and clustered.

RESULTS

Of the 1388 records obtained, 140 studies were included in the analysis. The 112 prospective and 28 retrospective studies investigated a total of 145 predictors. These were assigned to the four central clusters 'Imaging procedures' (n = 22), 'Physiological parameters' (n = 61), 'Scores and indices' (n = 53), and 'Machine learning models' (n = 9). The most frequently investigated predictors are the rapid shallow breathing index, the diaphragm thickening fraction, the respiratory rate, the P/F ratio, and the diaphragm excursion.

CONCLUSION

Predictors for weaning failure are widely researched. To date, 145 predictors have been investigated with varying intensity in 140 studies that are in line with the current weaning definition. It is no longer just individual predictors that are investigated, but more comprehensive assessments, indices and machine learning models in the last decade. Future research should be conducted in line with international weaning definitions and further investigate poorly researched predictors. Registration, Protocol: https://doi.org/10.17605/OSF.IO/2KDYU.

Assessment of Diaphragmatic Dysfunction in Mechanically Ventilated Patients with Ultrasonography

INTRODUCTION

The reliability of the diaphragm thickening fraction in predicting weaning failure in mechanically ventilated patients in the intensive care unit (ICU), as well as the relationship between the patients' diaphragmatic inspiratory excursion and diaphragmatic thickness.

MATERIALS AND METHODS

Fifty mechanically ventilated patients participated in this hospital-based cross-sectional prospective study in a tertiary care teaching hospital. Patients who had been on a mechanical ventilator for at least 7 days and whose legal guardian was willing to provide consent were also included in the research. People with hemodynamic instability and those whose legal guardians were reluctant to comply were excluded.

RESULTS

Using diaphragmatic thickening fraction as a diagnostic criterion, the weaning failure group consisted of 24 patients, out of which we predicted diaphragmatic dysfunction (DD) in 19 patients. The weaning success group consisted of 26 patients, of which we predicted no DD in 21 patients. Weaning success or failure was predicted by diaphragmatic thickening fraction with a sensitivity of 79.16% and a specificity of 80.76%, diaphragm excursion with a sensitivity of 70.8% and an 80.7%, and diaphragmatic thickness with a sensitivity of 66.66% and a specificity of 73.91%, respectively.

CONCLUSION

Diagnosing DD in mechanically ventilated, figuring out if extubation would be effective or not, monitoring respiratory effort, and assessing atrophy in ICU patients, ultrasonography may be an effective and accurate technique for mechanical ventilation patients, and it provides a convenient, noninvasive, affordable, and secure way to assess DD.

The diaphragmatic electrical activity during spontaneous breathing trial in patients with mechanical ventilation: physiological description and potential clinical utility

BACKGROUNDS

Increased respiratory drive has been demonstrated to correlate with weaning failure, which could be quantified by electrical activity of the diaphragm (EAdi). We described the physiological process of EAdi-based parameters during the spontaneous breathing trial (SBT) and evaluated the change of EAdi-based parameters as potential predictors of weaning failure.

METHODS

We conducted a prospective study in 35 mechanically ventilated patients who underwent a 2-hour SBT. EAdi and ventilatory parameters were continuously measured during the SBT. Diaphragm ultrasound was performed before the SBT and at the 30 min of the SBT. Three EAdi-based parameters were calculated: neuro-ventilatory efficiency, neuro-excursion efficiency and neuro-discharge per min.

RESULTS

Of the thirty 35 patients studied, 25 patients were defined as SBT success, including 22 patients weaning successfully and 3 patients reintubated. Before the SBT, neuro-excursion efficiency differed significantly between two groups and had the highest predictive value for SBT failure (AUROC 0.875, p < 0.01). Early increases in EAdi were observed in SBT, which are more prominent in SBT failure group. One minute, changes in EAdi and neuro-discharge per min also predicted weaning outcome (AUROCs 0.944 and 0.918, respectively).

CONCLUSIONS

EAdi-based parameters, especially neuro-excursion efficiency and changes in neuro-discharge per min, may detect impending weaning failure earlier than conventional indices. EAdi monitoring provides physiological insights and a more tailored approach to facilitate successful weaning. Further research should validate these findings and explore the utility of combined EAdi and diaphragm ultrasound assessment in weaning ICU patients from mechanical ventilation.

TRIAL REGISTRATION

Registered at ClinicalTrials.gov on 20 September 2022 (Identifier: NCT05632822).

Critical illness-associated limb and diaphragmatic weakness

PURPOSE OF REVIEW

In the current review, we aim to highlight the evolving evidence on the diagnosis, prevention and treatment of critical illness weakness (CIW) and critical illness associated diaphragmatic weakness (CIDW).

RECENT FINDINGS

In the ICU, several risk factors can lead to CIW and CIDW. Recent evidence suggests that they have different pathophysiological mechanisms and impact on outcomes, although they share common risk factors and may overlap in several patients. Their diagnosis is challenging, because CIW diagnosis is primarily clinical and, therefore, difficult to obtain in the ICU population, and CIDW diagnosis is complex and not easily performed at the bedside. All of these issues lead to underdiagnosis of CIW and CIDW, which significantly increases the risk of complications and the impact on both short and long term outcomes. Moreover, recent studies have explored promising diagnostic techniques that are may be easily implemented in daily clinical practice. In addition, this review summarizes the latest research aimed at improving how to prevent and treat CIW and CIDW.

SUMMARY

This review aims to clarify some uncertain aspects and provide helpful information on developing monitoring techniques and therapeutic interventions for managing CIW and CIDW.