Diaphragm dysfunction detected with ultrasound to predict noninvasive mechanical ventilation failure: A prospective cohort study

The Application of Diaphragm Ultrasound in Chronic Obstructive Pulmonary Disease: A Narrative Review

Chronic Obstructive Pulmonary Disease (COPD) is a prevalent condition that poses a significant burden on individuals and society due to its high morbidity and mortality rates. The diaphragm is the main respiratory muscle, its function has a direct impact on the quality of life and prognosis of COPD patients. This article aims to review the structural measurement and functional evaluation methods through the use of diaphragmatic ultrasound and relevant research on its application in clinical practice for COPD patients. Thus, it serves to provide valuable insights for clinical monitoring of diaphragm function in COPD patients, facilitating early clinical intervention and aiding in the recovery of diaphragm function.

Diaphragm Ultrasound in Different Clinical Scenarios: A Review with a Focus on Older Patients

Diaphragm muscle dysfunction is increasingly recognized as a fundamental marker of several age-related diseases and conditions including chronic obstructive pulmonary disease, heart failure and critical illness with respiratory failure. In older individuals with physical frailty and sarcopenia, the loss of muscle mass and function may also involve the diaphragm, contributing to respiratory dysfunction. Ultrasound has recently emerged as a feasible and reliable strategy to visualize diaphragm structure and function. In particular, it can help to predict the timing of extubation in patients undergoing mechanical ventilation in intensive care units (ICUs). Ultrasonographic evaluation of diaphragmatic function is relatively cheap, safe and quick and can provide useful information for real-time monitoring of respiratory function. In this review, we aim to present the current state of scientific evidence on the usefulness of ultrasound in the assessment of diaphragm dysfunction in different clinical settings, with a particular focus on older patients. We highlight the importance of the qualitative information gathered by ultrasound to assess the integrity, excursion, thickness and thickening of the diaphragm. The implementation of bedside diaphragm ultrasound could be useful for improving the quality and appropriateness of care, especially in older subjects with sarcopenia who experience acute respiratory failure, not only in the ICU setting.

Setting positive end-expiratory pressure: lung and diaphragm ultrasound

PURPOSE OF REVIEW

The purpose of this review is to summarize the role of lung ultrasound and diaphragm ultrasound in guiding ventilator settings with an emphasis on positive end-expiratory pressure (PEEP). Recent advances for using ultrasound to assess the effects of PEEP on the lungs and diaphragm are discussed.

RECENT FINDINGS

Lung ultrasound can accurately diagnose the cause of acute respiratory failure, including acute respiratory distress syndrome and can identify focal and nonfocal lung morphology in these patients. This is essential in determining optimal ventilator strategy and PEEP level. Assessment of the effect of PEEP on lung recruitment using lung ultrasound is promising, especially in the perioperative setting. Diaphragm ultrasound can monitor the effects of PEEP on the diaphragm, but this needs further validation. In patients with an acute exacerbation of chronic obstructive pulmonary disease, diaphragm ultrasound can be used to predict noninvasive ventilation failure. Lung and diaphragm ultrasound can be used to predict weaning outcome and accurately diagnose the cause of weaning failure.

SUMMARY

Lung and diaphragm ultrasound are useful for diagnosing the cause of respiratory failure and subsequently setting the ventilator including PEEP. Effects of PEEP on lung and diaphragm can be monitored using ultrasound.

Replacement of fluoroscopy by ultrasonography in the evaluation of hemidiaphragm function, an exploratory prospective study

INTRODUCTION

Dysfunction of the diaphragm may ultimately lead to respiratory insufficiency and compromise patient outcome. Evaluation of diaphragm function is cumbersome. Fluoroscopy has been the gold standard to measure diaphragmatic excursion. Ultrasonography can visualize diaphragm excursion and holds many advantages such as no radiation exposure, increased portability and accessibility. However, correlation between fluoroscopy and ultrasonography has never been studied. We aimed to compare fluoroscopic and ultrasound measures of diaphragm excursion to determine if ultrasonography can replace fluoroscopy.

METHODS

We performed ultrasound and fluoroscopy simultaneously during sniff inspiration and at total inspiratory capacity in patients with chronic obstructive pulmonary disease, heart failure and in healthy volunteers. Cranio-caudal excursion was measured by fluoroscopy and compared directly to M-mode excursion, B-mode excursion, area change, resting thickness, thickening fraction and contraction velocity measured by ultrasonography.

RESULTS

Forty-two participants were included. The Pearson correlation between M-mode and fluoroscopy excursion was 0.61. The slope was 0.9 (90%CI 0.76-1.04) in a regression analysis. Using the Bland-Altman method, the bias was - 0.39 cm (95% CI - 1.04-0.26), p = 0.24. The Pearson correlation between fluoroscopy and B-mode and area change ultrasonography was high; low for thickness and fraction. All correlations were lower during sniff inspiration compared with inspiratory capacity breathing.

CONCLUSION

Ultrasonography has an acceptable correlation and bias compared to fluoroscopy and can thus be used as the primary tool to evaluate diaphragm excursion.

The role of ultrasound in predicting non-invasive ventilation outcomes: a systematic review

Purpose

To systematically review and compare ultrasonographic methods and their utility in predicting non-invasive ventilation (NIV) outcomes.

Methods

A systematic review was performed using the PubMed, Medline, Embase, and Cochrane databases from January 2015 to March 2023. The search terms included the following: ultrasound, diaphragm, lung, prediction, non-invasive, ventilation, and outcomes. The inclusion criteria were prospective cohort studies on adult patients requiring non-invasive ventilation in the emergency department or inpatient setting.

Results

Fifteen studies were analyzed, which comprised of 1,307 patients (n = 942 for lung ultrasound score studies; n = 365 patients for diaphragm dysfunction studies). Lung ultrasound scores (LUS) greater than 18 were associated with NIV failure with a sensitivity 62-90.5% and specificity 60-91.9%. Similarly, a diaphragm thickening fraction (DTF) of less than 20% was also associated with NIV failure with a sensitivity 80-84.6% and specificity 76.3-91.5%.

Conclusion

Predicting NIV failure can be difficult by routine initial clinical impression and diagnostic work up. This systematic review emphasizes the importance of using lung and diaphragm ultrasound, in particular the lung ultrasound score and diaphragm thickening fraction respectively, to accurately predict NIV failure, including the need for ICU-level of care, requiring invasive mechanical ventilation, and resulting in higher rates of mortality.

Sonographic assessment of diaphragmatic thickness and excursion to predict CPAP failure in neonates below 34 weeks of gestation: A prospective cohort study

BACKGROUND

To evaluate the diagnostic accuracy of sonographic assessment of diaphragmatic dimensions and excursions in predicting Continuous Positive Airway Pressure (CPAP) failure in preterm neonates with respiratory distress.

METHODS

Prospective cohort study among preterm neonates less than 34 weeks of gestation who were hemodynamically stable and either admitted with respiratory distress or who developed respiratory distress shortly after admission to the NICU and having Silverman-Anderson Score (SAS) ≥ 3/10 were included. We performed sonographic assessment of diaphragmatic dimensions and excursions before and one hour ±30 minutes after application of CPAP. 'CPAP failure' was defined as combined outcome of the need of surfactant and/or upgradation of respiratory support within first 72 hours after a trial of CPAP. Clinical parameters and diaphragmatic measurements were compared between CPAP failure and success groups.

RESULTS

Of 62 participants, 20 (32%) failed CPAP. On binomial logistic regression (after adjustment for gestational age and birth weight), initial SAS, higher diaphragmatic excursion (both left and right, before and after CPAP application), lower left hemidiaphragm diaphragmatic thickness fraction (DTF) (before CPAP application) and lower right DTF (after CPAP application) were independent predictors of CPAP failure. However, the receiver-operating characteristics curves showed that excursions of right and left hemi-diaphragm both before and after CPAP application, had highest accuracies in predicting CPAP failure (AUC 0.84, 0.80 and 0.86, 0.78, respectively; p < .001).

CONCLUSION

Diaphragmatic excursion can be a useful parameter to predict the failure of CPAP in preterm neonates with respiratory distress.

The Incidence of Diaphragmatic Dysfunction in Patients Presenting With Dyspnea in the Emergency Department

OBJECTIVES

Diaphragmatic dysfunction has been reported as a cause of dyspnea, and its diagnosis can be made using ultrasound. Diaphragmatic ultrasound is mainly used to predict respiratory failure in chronic conditions. The use of diaphragmatic ultrasound has also risen in acute settings, such as emergency departments (EDs). However, the number of studies on its use still needs to be increased. The present study aimed to find the incidence of diaphragmatic dysfunction in the ED.

METHODS

This prospective cohort study was conducted in an ED. We enrolled patients aged greater than 18 years who presented with dyspnea. Diaphragmatic excursion and diaphragmatic thickness techniques were performed. The primary outcome was the incidence of diaphragmatic dysfunction. The secondary outcomes were the associations between diaphragmatic dysfunction and the composition of respiratory therapies within 24 hours, intubation within 24 hours, and 7-day mortality.

RESULTS

A total of 237 patients were analyzed. The incidences of diaphragmatic dysfunction assessed by diaphragmatic excursion and diaphragm thickness were 22.4 and 32.1%, respectively. Patients with sepsis and cancer had the highest incidences. Diaphragmatic dysfunction assessed by both techniques was not associated with the composition of respiratory support therapies within 24 hours, intubation within 24 hours, or 7-day mortality.

CONCLUSIONS

The incidence of diaphragmatic dysfunction in dyspneic patients in the ED ranged from 22.4 to 32.1%, depending on the ultrasound technique. Diaphragmatic dysfunction was not associated with the composition of respiratory support therapies, intubation, or mortality.

MRI-assessed diaphragmatic function can predict frequent acute exacerbation of COPD: a prospective observational study based on telehealth-based monitoring system

BACKGROUND

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) have considerably high mortality and re-hospitalisation rate. Diaphragmatic dysfunction (DD) is common in COPD patients. However, whether diaphragmatic dysfunction is related to acute exacerbation is yet to be elucidated. This study aimed to evaluate the diaphragm function by magnetic resonance imaging (MRI) in COPD patients and assess whether the impact of DD may help predict AECOPD.

METHODS

20 healthy adult volunteers and 80 COPD patients were enrolled. The diaphragms function parameters were accessed by MRI. Patients were guided to start self-management by the Telehealth-based monitoring system following the enrolment. Events of acute exacerbation of COPD were recorded by the system and confirmed by healthcare providers. Binary univariate and multivariate logistic regression analyses were performed to investigate the factors associated with the frequency of AECOPD. Receiver operating characteristic (ROC) curves were further used to assess the value of prediction indexes.

RESULTS

Fifty-nine COPD patients completed a one-year follow-up based on the Telehealth-based monitoring system. The clinical outcomes showed that the diaphragm function parameters at the end of maximal breathing were lower in the COPD group than in the healthy control group (P < 0.05). ANOVA showed significant differences among Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages for diaphragm function parameters, including chest wall motion, lung area, upper-lower diameter, and the diaphragm thickening fraction at the end of maximal breathing (P < 0.05). Moreover, significant differences in diaphragm function parameters were observed between patients with infrequent AECOPD (n = 28) and frequent AECOPD (n = 31) based on the frequency of AECOPD (P < 0.05). The diaphragm thickening fraction and the chest wall motion were associated with AECOPD after adjusting for age, sex, BMI, and lung functions, and the combination of predictions showed better accuracy in predicting the frequency of AECOPD.

CONCLUSIONS

In COPD patients, diaphragm function parameters correlate with the severity of airflow limitation. The diaphragm thickening fraction and the chest wall motion were associated with the frequency of AECOPD and can predict it.

General Anesthesia for Patients With Chronic Obstructive Pulmonary Disease and Postoperative Respiratory Failure: A Retrospective Analysis of 120 Patients

Background: Chronic obstructive pulmonary disease (COPD) has been considered a risk factor for postoperative respiratory failure after general anesthesia. However, the association between COPD severity and postoperative respiratory failure among COPD patients is unknown. Our aim was to compare the prevalence of postoperative respiratory failure in COPD patients according to disease severity after general anesthesia.

Methods: We retrospectively reviewed COPD patients undergoing spinal surgery with general anesthesia at our clinical center between January 2016 and January 2021. These subjects were divided into four groups (group I = mild COPD, group II = moderate COPD, group III = severe COPD, and group IV = very severe COPD) according to their preoperative lung function. The primary endpoint was a respiratory failure 1 week after surgery. The diagnosis of respiratory failure was made with the presence of one or more of the following criteria: prolonged ventilator dependence, unplanned postoperative intubation, and partial pressure of arterial oxygen (PaO₂) ≤ 50 mmHg while the patient was breathing ambient air in the hospital. The extubation time, perioperative PaO₂ and partial pressure of arterial carbon dioxide (PaCO₂), postoperative lung infection, and length of hospitalization were also compared.

Results: A total of 120 patients who underwent spinal surgery with general anesthesia were included in this retrospective study. Postoperative respiratory failure occurred in 0 (0.0%) patient in group I, 1 (1.5%) patient in group II, 1 (2.5%) patient in group III, and 1 (14.5%) patient in group IV 1 week after surgery (p = 0.219). The duration of anesthesia was 243.3 ± 104.3 min in group I, 235.5 ± 78.8 min in group II, 196.0 ± 66.3 min in group III, and 173.1 ± 63.7 min in group IV (p < 0.001). Preoperative PaO₂, PaCO₂, intraoperative oxygenation index [a ratio of PaO₂ to fraction of inspired oxygen (FiO₂)], and postoperative PaO₂ were significantly different among the four groups (p < 0.001, 0.001, 0.046, <0.001, respectively). No significant differences among the four groups were seen in extubation time, pulmonary infection, or hospital stay (p = 0.174, 0.843, 0.253, respectively). The univariate analysis revealed that higher preoperative PaO₂ was associated with a lower rate of postoperative respiratory failure (OR 0.83; 95% CI, 0.72 to 0.95; p = 0.007).

Conclusion: The severity of COPD as assessed with GOLD classification was not associated with the development of postoperative respiratory failure. However, lower preoperative PaO₂ was associated with greater odds of postoperative respiratory failure in COPD patients.

Research Progress on Diaphragm Ultrasound in Chronic Obstructive Pulmonary Disease: A Narrative Review

Chronic obstructive pulmonary disease (COPD) is a common disease of the respiratory system, and its prevalence and mortality remain high. COPD results in continuous impairment of lung function, which severely affects the patient's work and life. In severe cases, there will be acute respiratory failure, which endangers the lives of patients, and respiratory muscle dysfunction is one of the main reasons for this result. As the diaphragm is the most important inspiratory muscle, its dysfunction has a great impact on the deterioration of respiratory function in COPD patients. With the development of ultrasound, more and more studies have found that diaphragm ultrasound can play an important role in the diagnosis and treatment of COPD patients. The main purpose of this article is to review the research progress on diaphragm ultrasound in COPD and briefly introduce diaphragmatic ultrasound examination methods.

Procalcitonin kinetics to guide sequential invasive-noninvasive mechanical ventilation weaning in patients with acute exacerbation of chronic obstructive pulmonary disease and respiratory failure: procalcitonin's adjunct role

How to identify the optimum switch point of sequential invasive and noninvasive ventilation is the focus of clinical attention on the patients suffering from acute exacerbation of chronic obstructive pulmonary disease (AECOPD) complicated by acute respiratory failure (ARF). This study aims to explore the clinical significance of taking the change rate of procalcitonin (PCT) as identifying the timing of weaning on the mechanical ventilation for the patients of AECOPD followed by ARF as a complication. There were altogether 140 patients of AECOPD complicated with ARF, who were randomly selected and divided into a study group and a control group respectively. A change rate of serum PCT level exceeding 50% was taken as the switch point selection of tracheal intubation removal for the patients of the study group, while the ‘pulmonary infection control (PIC) window’ was done for those in the control group. With CRP, IL-6, TNF-a, PaCO_2, PaO_2, and Lac having been detected before and after treatment to them all, clinical indexes were obtained and compared between these two groups. The CRP, TNF-a, and IL-6 levels of the patients in the study group after treatment (p < 0.05) were lower than those in the control group. There was no significant difference in PaCO_2, PaO_2, and Lac between these two groups before and after treatment (p > 0.05). Even so, some other indexes available for the study group of patients were found to be lower than those for the control group (p < 0.05) in the following aspects: duration of invasive ventilation support, total time of mechanical ventilation support, incidence rate of ventilator-associated pneumonia, 48-hour reintubation rate, incidence rate of upper gastrointestinal bleeding, hospitalization time of critical respiratory illness, total hospitalization time, RICU treatment cost, total treatment cost, and mortality. It is preferable to take the change rate of PCT level exceeding 50% as the switch point of weaning time in sequential mechanical ventilation rather than the PIC window.

Abbreviations

AECOPD: acute exacerbation of chronic obstructive pulmonary disease; ARF: acute respiratory failure; PCT: procalcitonin; PaO₂: the oxygen partial pressure; PaCO₂: the partial pressure of carbon dioxide; TNF-a: serum tumor necrosis factor-a; IL-6: interleukin-6; CRP: serum C-reactive protein; PIC window: pulmonary infection control window; RICU: respiration and intensive care unit