Bedside ultrasound monitoring of prone position induced lung inflation

Establishment of seven lung ultrasound phenotypes: a retrospective observational study of an LUS registry

BACKGROUND

Lung phenotypes have been extensively utilized to assess lung injury and guide precise treatment. However, current phenotypic evaluation methods rely on CT scans and other techniques. Although lung ultrasound (LUS) is widely employed in critically ill patients, there is a lack of comprehensive and systematic identification of LUS phenotypes based on clinical data and assessment of their clinical value.

METHODS

Our study was based on a retrospective database. A total of 821 patients were included from September 2019 to October 2020. 1902 LUS examinations were performed in this period. Using a dataset of 55 LUS examinations focused on lung injuries, a group of experts developed an algorithm for classifying LUS phenotypes based on clinical practice, expert experience, and lecture review. This algorithm underwent validation and refinement with an additional 140 LUS images, leading to five iterative revisions and the generation of 1902 distinct LUS phenotypes. Subsequently, a validated machine learning algorithm was applied to these phenotypes. To assess the algorithm's effectiveness, experts manually verified 30% of the phenotypes, confirming its efficacy. Using K-means cluster analysis and expert image selection from the 1902 LUS examinations, we established seven distinct LUS phenotypes. To further explore the diagnostic value of these phenotypes for clinical diagnosis, we investigated their auxiliary diagnostic capabilities.

RESULTS

A total of 1902 LUS phenotypes were tested by randomly selecting 30% to verify the phenotypic accuracy. With the 1902 LUS phenotypes, seven lung ultrasound phenotypes were established through statistical K-means cluster analysis and expert screening. The acute respiratory distress syndrome (ARDS) exhibited gravity-dependent phenotypes, while the cardiogenic pulmonary edema exhibited nongravity phenotypes. The baseline characteristics of the 821 patients included age (66.14 ± 11.76), sex (560/321), heart rate (96.99 ± 23.75), mean arterial pressure (86.5 ± 13.57), Acute Physiology and Chronic Health Evaluation II (APACHE II)score (20.49 ± 8.60), and duration of ICU stay (24.50 ± 26.22); among the 821 patients, 78.8% were cured. In severe pneumonia patients, the gravity-dependent phenotype accounted for 42% of the cases, whereas the nongravity-dependent phenotype constituted 58%. These findings highlight the value of applying different LUS phenotypes in various diagnoses.

CONCLUSIONS

Seven sets of LUS phenotypes were established through machine learning analysis of retrospective data; these phenotypes could represent the typical characteristics of patients with different types of critical illness.

Developing a predictive nomogram for mortality in patients with extrapulmonary acute respiratory distress syndrome: the prognostic value of serum soluble thrombomodulin, lung ultrasound score, and lactate

Objective: This study aimed to elucidate the prognostic significance of serum soluble thrombomodulin (sTM), lung ultrasound score (LUS), and lactate levels in patients with extrapulmonary acute respiratory distress syndrome (ARDS), with the goal of refining mortality risk prediction in this cohort. Methods: In a prospective cohort of 95 patients with extrapulmonary ARDS admitted to the intensive care unit, we investigated the primary endpoint of 28-day mortality. Utilizing Lasso-Cox regression analysis, we identified independent prognostic factors for mortality. A predictive nomogram was developed incorporating these factors, and its performance was validated through several statistical measures, including the consistency index, calibration plot, internal validation curve, decision curve analysis, interventions avoided analysis, receiver operating characteristic curve analysis, and Kaplan-Meier survival analysis. We further conducted a subgroup analysis to examine the impact of prone positioning on patient outcomes. Results: The study identified baseline serum sTM, LUS, and lactate levels as independent predictors of 28-day mortality in extrapulmonary ARDS patients. The predictive nomogram demonstrated superior prognostic accuracy compared to the use of sTM, LUS, or lactate levels alone, and outperformed traditional prognostic tools such as the Acute Physiology and Chronic Health Evaluation II score and the partial pressure of arterial oxygen to fractional inspired oxygen ratio. The subgroup analysis did not show a significant impact of prone positioning on the predictive value of the identified biomarkers. Conclusion: Our study results support the development and validation of a novel prognostic nomogram that integrates key clinical biomarkers and ultrasound imaging scores to predict mortality in patients with extrapulmonary ARDS. While our research is preliminary, further studies and validation are required.

The use of diaphragm and lung ultrasound in acute respiratory physiotherapy practice and the impact on clinical decision-making: A systematic review and meta-analysis

OBJECTIVES

Diaphragm and lung ultrasound (DLUS) is emerging as an important point-of-care respiratory assessment tool and is being used in clinical care by trained respiratory physiotherapists, both in Australia and internationally. However, the impact of DLUS on physiotherapists' clinical decision-making remains largely unknown. This systematic review aims to review the evidence for implementing DLUS in acute respiratory physiotherapy management.

REVIEW METHOD USED

We conducted a systematic review.

DATA SOURCES

We searched PubMed, Embase, CINAHL, CENTRAL, and Scopus from inception to 18th April 2023 for all original clinical studies reporting on the physiotherapy clinical decision-making, following a DLUS examination and/or where DLUS was used to evaluate the effect of respiratory physiotherapy, in adults over 18 years of age.

REVIEW METHODS

Two authors independently performed study selection and data extraction. Individual study risk of bias was assessed using the Newcastle-Ottawa Scale, and certainty in outcomes was assessed using the Grading of Recommendations, Assessment, Development, and Evaluations framework.

RESULTS

A total of seven observational studies (n = 299) were included, all of which were in the intensive care setting. DLUS changed physiotherapy diagnosis, management, and treatment in 63.9% (50-64%), 16.8% (15-50%), and 48.4% (25-50%) of patients, respectively. There was a significant improvement in the lung ultrasound score post respiratory physiotherapy treatment (mean difference -2.31, 95% Confidence Interval (95% CI) -4.42 to -0.21; very low certainty) compared to before respiratory physiotherapy treatment. Moderate risk of bias was present in six studies, and there was variance in the DLUS methodology across included studies.

CONCLUSIONS

The findings of this review suggest DLUS influences physiotherapy clinical decision-making and can be used to evaluate the effects of acute respiratory physiotherapy treatment. However, the available data is limited, and further high-quality studies are needed.

TRIAL REGISTRATION

This study is registered with the International Prospective Register of Systematic Reviews; CRD42023418312.

Mechanical power normalized to aerated lung predicts noninvasive ventilation failure and death and contributes to the benefits of proning in COVID-19 hypoxemic respiratory failure

Background

Concern exists that noninvasive ventilation (NIV) may promote ventilation-induced lung injury(VILI) and worsen outcome in acute hypoxemic respiratory failure (AHRF). Different individual ventilatory variables have been proposed to predict clinical outcomes, with inconsistent results.Mechanical power (MP), a measure of the energy transfer rate from the ventilator to the respiratory system during mechanical ventilation, might provide solutions for this issue in the framework of predictive, preventive and personalized medicine (PPPM). We explored (1) the impact of ventilator-delivered MP normalized to well-aerated lung (MP_WAL) on physio-anatomical and clinical responses to NIV in COVID-19-related AHRF and (2) the effect of prone position(PP) on MP_WAL.

Methods

We analyzed 216 noninvasively ventilated COVID-19 patients (108 patients receiving PP + NIV and 108 propensity score-matched patients receiving supine NIV) with moderate-to-severe(paO2/FiO2 ratio < 200) AHRF enrolled in the PRO-NIV controlled non-randomized study (ISRCTN23016116).Quantification of differentially aerated lung volumes by lung ultrasonography (LUS) was validated against CT scans. Respiratory parameters were hourly recorded, ABG were performed 1 h after each postural change. Time-weighed average values of ventilatory variables, including MP_WAL, and gas exchange parameters (paO2/FiO2 ratio, dead space indices) were calculated for each ventilatory session. LUS and circulating biomarkers were assessed daily.

Results

Compared with supine position, PP was associated with a 34% MP_WAL reduction, attributable largely to an absolute MP reduction and secondly to an enhanced lung reaeration.Patients receiving a high MP_WAL during the 1^st 24 h of NIV [MP_WAL(day 1)] had higher 28-d NIV failure (HR = 4.33,95%CI:3.09 - 5.98) and death (HR = 5.17,95%CI: 3.01 - 7.35) risks than those receiving a low MP_WAL(day 1).In Cox multivariate analyses, MP_WAL(day 1) remained independently associated with 28-d NIV failure (HR = 1.68,95%CI:1.15-2.41) and death (HR = 1.69,95%CI:1.22-2.32).MP_WAL(day 1) outperformed other power measures and ventilatory variables as predictor of 28-d NIV failure (AUROC = 0.89;95%CI:0.85-0.93) and death (AUROC = 0.89;95%CI:0.85-0.94).MP_WAL(day 1) predicted also gas exchange, ultrasonographic and inflammatory biomarker responses, as markers of VILI, on linear multivariate analysis.

Conclusions

In the framework of PPPM, early bedside MP_WAL calculation may provide added value to predict response to NIV and guide subsequent therapeutic choices i.e. prone position adoption during NIV or upgrading to invasive ventilation, to reduce hazardous MP_WAL delivery, prevent VILI progression and improve clinical outcomes in COVID-19-related AHRF.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-023-00325-5.

Concise Versus Extended Lung Ultrasound Score to Monitor Critically Ill Patients With COVID-19

BACKGROUND

Lung ultrasound (LUS) can be used to monitor critically ill patients with COVID-19, but the optimal number of examined lung zones is disputed.

METHODS

This was a prospective observational study. The objective was to investigate whether concise (6 zones) and extended (12 zones) LUS scoring protocols are clinically equivalent in critically ill ICU subjects with COVID-19. The primary outcome of this study was (statistical) agreement between concise and extended LUS score index evaluated in both supine and prone position. Agreement was determined using correlation coefficients and Bland-Altman plots to detect systematic differences between protocols. Secondary outcomes were difference between LUS score index in supine and prone position using similar methods.

RESULTS

We included 130 LUS examinations in 40 subjects (mean age 69.0 ± 8.5y, 75% male). Agreement between concise and extended LUS score index had no clinically relevant constant or proportional bias and limits of agreement were below the smallest detectable change. Across position changes, supine LUS score index was 8% higher than prone LUS score index and had limits above the smallest detectable change, indicating true LUS score index differences between protocols may occur due to the position change itself. Lastly, inter-rater and intra-rater agreement were very good.

CONCLUSIONS

Concise LUS was equally informative as extended LUS for monitoring critically ill subjects with COVID-19 in supine or prone position. Clinicians can monitor patients undergoing position changes but must be wary that LUS score index alterations may result from the position change itself rather than disease progression or clinical improvement.

Prone positioning in ARDS patients supported with VV ECMO, what we should explore?

Background

Acute respiratory distress syndrome (ARDS), a prevalent cause of admittance to intensive care units, is associated with high mortality. Prone positioning has been proven to improve the outcomes of moderate to severe ARDS patients owing to its physiological effects. Venovenous extracorporeal membrane oxygenation (VV ECMO) will be considered in patients with severe hypoxemia. However, for patients with severe hypoxemia supported with VV ECMO, the potential effects and optimal strategies of prone positioning remain unclear. This review aimed to present these controversial questions and highlight directions for future research.

Main body

The clinically significant benefit of prone positioning and early VV ECMO alone was confirmed in patients with severe ARDS. However, a number of questions regarding the combination of VV ECMO and prone positioning remain unanswered. We discussed the potential effects of prone positioning on gas exchange, respiratory mechanics, hemodynamics, and outcomes. Strategies to achieve optimal outcomes, including indications, timing, duration, and frequency of prone positioning, as well as the management of respiratory drive during prone positioning sessions in ARDS patients receiving VV ECMO, are challenging and controversial. Additionally, whether and how to implement prone positioning according to ARDS phenotypes should be evaluated. Lung morphology monitored by computed tomography, lung ultrasound, or electrical impedance tomography might be a potential indication to make an individualized plan for prone positioning therapy in patients supported with VV ECMO.

Conclusion

For patients with ARDS supported with VV ECMO, the potential effects of prone positioning have yet to be clarified. Ensuring an optimal strategy, especially an individualized plan for prone positioning therapy during VV ECMO, is particularly challenging and requires further research.

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.

Effect of awake prone position on diaphragmatic thickening fraction in patients assisted by noninvasive ventilation for hypoxemic acute respiratory failure related to novel coronavirus disease

BACKGROUND

Awake prone position is an emerging rescue therapy applied in patients undergoing noninvasive ventilation (NIV) for acute hypoxemic respiratory failure (ARF) related to novel coronavirus disease (COVID-19). Although applied to stabilize respiratory status, in awake patients, the application of prone position may reduce comfort with a consequent increase in the workload imposed on respiratory muscles. Thus, we primarily ascertained the effect of awake prone position on diaphragmatic thickening fraction, assessed through ultrasound, in COVID-19 patients undergoing NIV.

METHODS

We enrolled all COVID-19 adult critically ill patients, admitted to intensive care unit (ICU) for hypoxemic ARF and undergoing NIV, deserving of awake prone positioning as a rescue therapy. Exclusion criteria were pregnancy and any contraindication to awake prone position and NIV. On ICU admission, after NIV onset, in supine position, and at 1 h following awake prone position application, diaphragmatic thickening fraction was obtained on the right side. Across all the study phases, NIV was maintained with the same setting present at study entry. Vital signs were monitored throughout the entire study period. Comfort was assessed through numerical rating scale (0 the worst comfort and 10 the highest comfort level). Data were presented in median and 25th-75th percentile range.

RESULTS

From February to May 2021, 20 patients were enrolled and finally analyzed. Despite peripheral oxygen saturation improvement [96 (94-97)% supine vs 98 (96-99)% prone, p = 0.008], turning to prone position induced a worsening in comfort score from 7.0 (6.0-8.0) to 6.0 (5.0-7.0) (p = 0.012) and an increase in diaphragmatic thickening fraction from 33.3 (25.7-40.5)% to 41.5 (29.8-50.0)% (p = 0.025).

CONCLUSIONS

In our COVID-19 patients assisted by NIV in ICU, the application of awake prone position improved the oxygenation at the expense of a greater diaphragmatic thickening fraction compared to supine position. Trial registration ClinicalTrials.gov, number NCT04904731. Registered on 05/25/2021, retrospectively registered. https://clinicaltrials.gov/ct2/show/NCT04904731 .