Evaluation of Abdominal Expiratory Muscle Thickness Pattern, Diaphragmatic Excursion, and Lung Ultrasound Score in Critically Ill Patients and Their Association with Weaning Patterns: A Prospective Observational Study

Accuracy of respiratory muscle assessments to predict weaning outcomes: a systematic review and comparative meta-analysis

BACKGROUND

Several bedside assessments are used to evaluate respiratory muscle function and to predict weaning from mechanical ventilation in patients on the intensive care unit. It remains unclear which assessments perform best in predicting weaning success. The primary aim of this systematic review and meta-analysis was to summarize and compare the accuracy of the following assessments to predict weaning success: maximal inspiratory (PImax) and expiratory pressures, diaphragm thickening fraction and excursion (DTF and DE), end-expiratory (Tdiee) and end-inspiratory (Tdiei) diaphragm thickness, airway occlusion pressure (P0.1), electrical activity of respiratory muscles, and volitional and non-volitional assessments of transdiaphragmatic and airway opening pressures.

METHODS

Medline (via Pubmed), EMBASE, Web of Science, Cochrane Library and CINAHL were comprehensively searched from inception to 04/05/2023. Studies including adult mechanically ventilated patients reporting data on predictive accuracy were included. Hierarchical summary receiver operating characteristic (HSROC) models were used to estimate the SROC curves of each assessment method. Meta-regression was used to compare SROC curves. Sensitivity analyses were conducted by excluding studies with high risk of bias, as assessed with QUADAS-2. Direct comparisons were performed using studies comparing each pair of assessments within the same sample of patients.

RESULTS

Ninety-four studies were identified of which 88 studies (n = 6296) reporting on either PImax, DTF, DE, Tdiee, Tdiei and P0.1 were included in the meta-analyses. The sensitivity to predict weaning success was 63% (95% CI 47-77%) for PImax, 75% (95% CI 67-82%) for DE, 77% (95% CI 61-87%) for DTF, 74% (95% CI 40-93%) for P0.1, 69% (95% CI 13-97%) for Tdiei, 37% (95% CI 13-70%) for Tdiee, at fixed 80% specificity. Accuracy of DE and DTF to predict weaning success was significantly higher when compared to PImax (p = 0.04 and p < 0.01, respectively). Sensitivity and direct comparisons analyses showed that the accuracy of DTF to predict weaning success was significantly higher when compared to DE (p < 0.01).

CONCLUSIONS

DTF and DE are superior to PImax and DTF seems to have the highest accuracy among all included respiratory muscle assessments for predicting weaning success. Further studies aiming at identifying the optimal threshold of DTF to predict weaning success are warranted.

TRIAL REGISTRATION

PROSPERO CRD42020209295, October 15, 2020.

Electrodiagnostic and ultrasound evaluation of respiratory weakness

Phrenic nerve conduction studies (NCSs) and needle electromyography (EMG) can provide important information on the underlying pathophysiology in patients presenting with unexplained shortness of breath, failure to wean from the ventilator, or consideration of phrenic nerve pacemaker implantation. However, these techniques are often technically challenging, require experience, can lack sensitivity and specificity, and, in the case of diaphragm EMG, involve some degree of risk. Diagnostic high-resolution ultrasound has been introduced in recent years as an adjuvant technique readily available at the bedside that can increase the overall sensitivity and specificity of the neurophysiologic evaluation of respiratory symptoms. Two-dimensional ultrasound in the zone of apposition can identify atrophy and evaluate contractility of the diaphragm, in addition to localizing a safe zone for needle EMG. M-mode ultrasound can identify decreased excursion or paradoxical motion of the diaphragm and can increase the reliability of phrenic NCSs. When used in combination, ultrasound, phrenic NCSs and EMG of the diaphragm can differentiate neuropathic, myopathic, and central disorders, and can offer aid in prognosis that is difficult to arrive at solely from clinical examination. This article will review techniques to successfully perform phrenic NCSs, needle EMG of the diaphragm, and ultrasound of the diaphragm. The discussion will include technical pitfalls and clinical pearls as well as future directions and clinical indications.

Is the mNutric Score, the Only Independent Risk Factor for Abdominal Muscle Thickness Influencing Weaning?

How to cite this article: Goswami A, Bhattacharya D, Mandal M, Esquinas AM. Is the mNutric Score, the Only Independent Risk Factor for Abdominal Muscle Thickness Influencing Weaning? Indian J Crit Care Med 2023;27(9):686-687.

Author's Response to Letter to the Editor "Is the mNUTRIC Score the Only Independent Risk Factor for Abdominal Muscle Thickness Influencing Weaning?"

How to cite this article: Chaudhuri S, Parampalli V. Author's Response to Letter to the Editor "Is the mNUTRIC Score the Only Independent Risk Factor for Abdominal Muscle Thickness Influencing Weaning?". Indian J Crit Care Med 2023;27(9):692-693.

Prediction of Successful Spontaneous Breathing Trial and Extubation of Trachea by Lung Ultrasound in Mechanically Ventilated Patients in Intensive Care Unit

Introduction

Spontaneous breathing trial (SBT) is always successful in mechanically ventilated patients. This study was conducted to assess the prediction of successful SBT and extubation of trachea by bedside lung ultrasound in mechanically ventilated patients.

Methodology

This was a prospective observational study for 1 year conducted at a tertiary teaching hospital ICU on 102 patients with age more than 18 years and who were mechanically ventilated for more than 24 hours. Bedside lung ultrasound was used to assess the lung ultrasound score (LUS) and lung profiles in patients who clinically met the criteria for SBT. The LUS at the beginning of SBT and 30 minutes after SBT were used to predict the successful SBT and tracheal extubation.

Result

Spontaneous breathing trial and tracheal extubation were successful in 73 (71.6%) and 57 (55.8%) of the patients. The AUC for lung ultrasound in predicting successful SBT at the beginning and 30 minutes of SBT were 0.781 (CI 95% 0.674-0.888, p < 0.001) and 0.841 (CI 95% 0.742-0.941, p < 0.001) with a cut-off value of 17.5 and 19.5, respectively. Similarly, AUC for LUS in relation to tracheal extubation was 0.786 (CI 95% 0.694-0.879, p < 0.001) and 0.841(CI 95% 0.756-0.925, p < 0.001) at 0 and 30 minutes. About 57.5% of the patients with A profiles tolerated successful SBT while 48.3% of the patients having C profile had failed SBT (p < 0.001). COPD, lung ultrasound, higher SOFA score, and longer duration of mechanical ventilation had a statistically significant negative correlation with successful SBT.

Conclusion

Lower LUS and A profiles lung ultrasound are associated with more successful weaning and tracheal extubation in mechanically ventilated patients.

How to cite this article

Rajbanshi LK, Bajracharya A, Devkota D. Prediction of Successful Spontaneous Breathing Trial and Extubation of Trachea by Lung Ultrasound in Mechanically Ventilated Patients in Intensive Care Unit. Indian J Crit Care Med 2023;27(7):482-487.

Risk Factors of Decreased Abdominal Expiratory Muscle Thickness in Mechanically Ventilated Critically Ill Patients-The mNUTRIC Score is an Independent Predictor

Background

The expiratory abdominal skeletal muscles are an important component of the respiratory muscle pump, and their reduced thickness has been associated with difficult weaning. There is no objective score that may help clinicians to predict expiratory abdominal muscle thinning.

Patients and methods

This was a single-center retrospective study on 81 patients undergoing weaning from mechanical ventilation. The thickness of the four abdominal expiratory muscles-rectus abdominis (RA), internal oblique (IO), external oblique (EO), and transversus abdominis (TA) on the day of the first spontaneous breathing trial (SBT), was obtained. The various parameters of the patients with thinner RA, IO, EO, and TA below the determined thickness cut-off values, predicting difficult weaning was analyzed.

Results

Modified nutritional risk in critically ill (mNUTRIC) score was found to be an independent predictor of thinner IO muscle after logistic regression analysis [p = 0.001, adjusted OR 2.33, 95% CI (1.394-3.892)]. The mNUTRIC score was also an independent predictor of thinner EO (p = 0.014, adjusted OR 1.57) and RA muscle (p = 0.002, adjusted OR 1.69). The mNUTRIC cutoff score ≥4 predicted thinner IO (AUC 0.813, p < 0.001 sensitivity 71%, specificity 77%) and thinner EO (AUC 0.738, p < 0.001, 71% sensitivity, 67% specificity). The mNUTRIC score ≥3 predicted that at least one out of the four abdominal expiratory muscles will be thin (AUC 0.849, p < 0.001, 95% CI [0.763-0.935], sensitivity 87.5%, specificity 59%).

Conclusion

The mNUTRIC score is an independent predictor of thinner abdominal expiratory muscles in mechanically ventilated critically ill patients.

How to cite this article

Vishwas P, Amara V, Maddani SS, Chaudhuri S, Podder S. Risk Factors of Decreased Abdominal Expiratory Muscle Thickness in Mechanically Ventilated Critically Ill Patients-The mNUTRIC Score is an Independent Predictor. Indian J Crit Care Med 2023;27(1):8-15.

Expiratory Muscles of Respiration and Weaning Failure: What do We Know So Far?

How to cite this article: Majeed NA, Nasa P. Expiratory Muscles of Respiration and Weaning Failure: What do We Know So Far? Indian J Crit Care Med 2023;27(1):1-3.

Diaphragm Evaluation and Lung Ultrasound Score during Weaning

How to cite this article: Blanco JB, Esquinas A. Diaphragm Evaluation and Lung Ultrasound Score during Weaning. Indian J Crit Care Med 2022;26(9):1054–1055.