Pulmonary ultrasound scoring system for intubated critically ill patients and its association with clinical metrics and mortality: A prospective cohort study

Abstract

Purpose: Pulmonary ultrasound (PU) examination at the point-of-care can rapidly identify the etiology of acute respiratory failure (ARF) and assess treatment response. The often-subjective classification of PU abnormalities makes it difficult to document change over time and communicate findings across providers. The study goal was to develop a simple, PU scoring system that would allow for standardized documentation, have high interprovider agreement, and correlate with clinical metrics. Methods:In this prospective study of 250 adults intubated for ARF, a PU examination was performed at intubation, 48-hours later, and at extubation. A total lung score (TLS) was calculated.Clinical metrics and final diagnosis were extracted from the medical record.Results: TLS correlated positively with mortality (P 5 .03), ventilator hours (P 5 .003), intensive care unit, and hospital length of stay (P 5 .003, P 5 .008), and decreasing PaO 2 /FiO 2 (P < .001).Agreement of PU findings was very good (kappa 5 0.83). Baseline TLS and subscores differed significantly between ARF categories (nonpulmonary, obstructive, and parenchymal disease).Conclusions: A quick, scored, PU examination was associated with clinical metrics, including mortality among a diverse population of patients intubated for ARF. In addition to diagnostic and prognostic information at the bedside, a standardized and quantifiable approach to PU provides objectivity in serial assessment and may enhance communication of findings between providers. K E Y W O R D Sintubation, point-of-care ultrasound, pulmonary ultrasonography, respiratory insufficiency | I N TR ODU C TI ONPulmonary ultrasound (PU) has become an essential tool for rapidly identifying the etiology of acute respiratory failure (ARF), following treatment progress, and clarifying nonspecific chest radiograph (CXR) abnormalities among critically ill patients, 1-5 and with test characteristics better than the clinical examination and CXR. 6,7 When used in combination with cardiac and vascular ultrasound, it can enhance the understanding of etiology 3 and may reduce the need for CXR or chest CT. [8][9][10] Acquisition, interpretation, and integration of PU findings at an isolated point in time are essential to prompt and accurate diagnosis.Tracking PU changes over time is equally important in confirming a diagnosis and adjusting treatment. To do so requires a standardized approach to PU such that providers can document and agree not only with themselves but also with each other over time. [11][12][13][14] PU scoring models have been developed to meet the need for standardization and have been shown to correlate with various metrics in specific patient populations. 5,11,[15][16][17] Scoring systems correlate with mortality in patients with acute respiratory distress syndrome

The diagnostic accuracy for ARDS of global versus regional lung ultrasound scores - a post hoc analysis of an observational study in invasively ventilated ICU patients

“…The lung aeration scores reported here are very much in line with those from previous investigations [17, 28–30]. Mean global scores in patients with ARDS varied between 18 and 21 in several reports [17, 28, 29], which was confirmed in the present cohort. The previously reported higher global scores with increasing ARDS severity [30] was also found in ARDS patients in the here studied cohort, albeit with a less pronounced linearity.…”

“…In line with a previous study, patients without ARDS had a relatively high global score [17]. While aeration was affected in both anterior and posterior regions in the previous study [17], in the present investigation it was the posterior score that contributed most to the global score. This difference may have been caused by the fact that unlike the previous study in which 9 lung points were scanned, here a 12-region approach was used.…”

“…All abnormalities in each region count equally within the final score, even while the relative importance and meaning of these abnormalities may be very different. Specifically, the signal-to-noise ratio could be low in those regions that are subject to the development of abnormalities other than ARDS, which is particularly true for posterior regions where compressive and perioperative atelectasis, pre-existing or new infiltrates, and hydrostatic pulmonary edema may concentrate due to a positional gradient [11, 17–20].…”

Diaphragm and Lung Ultrasonography During Weaning From Mechanical Ventilation in Critically Ill Patients

“…Posterior regions have higher diagnostic accuracy in the assessment of hydrostatic pulmonary edema due to atelectasis and infiltration [26][27][28]. However, compared to the posterior score with the global score, the diagnostic accuracy of the posterior score is low in ARDS patients, and the removal of the posterior regions from the global score leads to no change in the diagnostic accuracy [25].…”

Lung ultrasound score before and after extubation for predicting weaning outcome

“…Additional 3 score for consolidation and 1 score for atelectasis or pleural effusion. 7,8 Patients were kept in the semi-recumbent position throughout the study. Positive end expiratory pressure (PEEP), inspiratory pressure support (IPS) and fraction of inspired oxygen (FiO2), set prior to the examination were not modified throughout the study.…”