Evaluating the effectiveness of handheld ultrasound in primary blast lung injury: a comprehensive study

Abstract

The incidence of blast injuries has been rising globally, particularly affecting the lungs due to their vulnerability. Primary blast lung injury (PBLI) is associated with high morbidity and mortality rates, while early diagnostic methods are limited. With advancements in medical technology, and portable handheld ultrasound devices, the efficacy of ultrasound in detecting occult lung injuries early remains unclear. This study evaluates the effectiveness of immediate lung ultrasound in diagnosing PBLI. The study involved 25 healthy male Bama mini-pigs subjected to BST-I-type biological shock wave tubes. The pigs were randomly assigned to non-injured and injured groups with driving pressures of 4.0 MPa, 4.5 MPa, and 4.8 MPa. Four PBLI models were created: no injury, minor, moderate, serious and severe. Immediate lung ultrasound following the BLUE-PLUS protocol and arterial blood gas analysis were conducted pre-injury and 0.5 h, 3 h, 6 h, 12 h, and 24 h post-injury, respectively. The study analyzed lung ultrasound score differences and their correlations with lung function parameters, using ROC analysis to determine early diagnostic standards and mortality prediction efficacy. The study found that in cases of moderate and severe PBLI, lung ultrasound scores and AaDO₂ significantly increased at 0.5 h post-injury, while PaO₂ decreased. There was good consistency between left and right lung ultrasound results at all times. Lung ultrasound scores were significantly correlated with PaO₂ and AaDO₂ but not with PaCO₂. The scores accurately predicted injury severity at various time points within 24 h post-injury, and the 0.5 h lung ultrasound score predicted 24 h mortality with 95.8% efficiency. PBLI exhibits hidden severity, necessitating improved early diagnostics. Immediate lung ultrasound provides effective differentiation for moderate and severe PBLI at multiple time points within 24 h post-injury, is easy to implement, and offers effective mortality risk prediction as early as 0.5 h post-injury. These findings underscore lung ultrasound's significant clinical application value in pre-hospital early treatment settings for PBLI.

Keywords: BLUE-PLUS protocol; Lung function; Point-of-care ultrasound (POCUS); Primary blast lung injury; Shock wave tube; Ultrasound.

Fig. 1

Diagram of the BLUE-PLUS protocol for lung ultrasound. (A) Setup during animal injury. (B) Ultrasound surface positioning. (C) Simplified ultrasound positioning diagram.

Fig. 2

Correspondence between lung pathology, gross anatomy, and ultrasound images. Ultrasound. White arrows: A lines. Red arrows: B lines. Continuous-line arrows: coalescent B lines. Oval: tissue-like pattern. Gross anatomical manifestations of PBLI in varying degrees. Yellow circle: Partial lung tissue of HE staining. HE staining of lung tissue (200×). Yellow arrows point to inflammatory cells. Green arrows point to red blood cells. Blue arrows point to pulmonary interstitial edema. Black arrows point to alveolar rupture.

Fig. 3

Changes in Lung Function Parameters in PBLI. (A) PO₂ (F = 8.893, p < 0.001) showed statistically significant differences between injury grades, with PO₂ levels decreasing in minor PBLI at 0.5 h (p < 0.001) and 12 h (p = 0.011); in moderate PBLI, PO₂ decreased at 0.5 h (p < 0.001), 3 h (p = 0.008), 6 h (p = 0.001), 12 h (p = 0.004), and 24 h (p = 0.017); in severe and serious PBLI PO₂ decreased at 0.5 h (p < 0.001), 3 h (p = 0.006), 6 h (p < 0.001), 12 h (p < 0.001), and 24 h (p = 0.001) . (B) PCO₂ (F = 1.997, p = 0.026) showed that in minor PBLI PCO₂ decreased at 0.5 h (p = 0.001) and 6 h (p = 0.011), in moderate PBLI PCO₂ decreased at 0.5 h (p < 0.001), 3 h (p = 0.006), 6 h (p = 0.001), 12 h (p < 0.001), and 24 h (p = 0.001), in severe and serious PBLI PCO₂ increased at 0.5 h (p < 0.001), while it decreased at 3 h (p = 0.008), 6 h (p = 0.001), 12 h (p = 0.004), and 24hs (p = 0.017). (C) AaDO₂ (F = 17.107, p < 0.001) showed that in minor PBLI AaDO₂ decreased at 0.5 h (p < 0.001), 3 h (p = 0.009), 6 h (p < 0.001), and 12 h (p = 0.005), in moderate PBLI AaDO₂ decreased at 0.5 h (p < 0.001), 3 h (p < 0.001), 6 h (p < 0.001), 12 h (p < 0.001), and 24 h (p < 0.001),in severe and serious PBLI AaDO₂ decreased at 0.5 h (p < 0.001), 3 h (p = 0.001), 6 h (p < 0.001), 12 h (p < 0.001), and 24 h (p < 0.001). *p < 0.05, †p < 0.01, $p < 0.001. Comparisons were made using RM ANOVA between groups and within groups at each time point post-injury vs. pre-injury.

Fig. 4

Trends in Lung Ultrasound Scores across Different Injury Severities within 24 h Post-Injury. (A) cLUSS (F = 40.154, p < 0.001) showed a significant increase in minor PBLI at 0.5 h (p = 0.000), 3 h (p < 0.001), 6 h (p = 0.002), and 12 h (p = 0.006). Moderate PBLI revealed elevated cLUSS scores at 0.5 h (p < 0.001), 3 h (p < 0.001), 6 h (p < 0.001), 12 h (p < 0.001), and 24 h (p < 0.001). Serious and severe PBLI also showed increased cLUSS scores at 0.5 h (p < 0.001), 3 h (p < 0.001), 6 h (p < 0.001), 12 h (p < 0.001), and 24 h (p < 0.001). (B) R-cLUSS (F = 3.267, p = 0.005) demonstrated a rise in minor PBLI at 0.5 h (p = 0.009), 3 h (p < 0.001), 6 h (p = 0.002), and 12 h (p < 0.001). Moderate PBLI exhibited increased ultrasonographic scores at 0.5 h (p < 0.001), 3 h (p < 0.001), 6 h (p < 0.001), 12 h (p < 0.001), and 24 h (p < 0.001) post-injury. Serious and severe PBLI also displayed elevated ultrasonographic scores at 0.5 h (p < 0.001), 3 h (p < 0.001), 6 h (p < 0.001), 12 h (p < 0.001), and 24 h (p < 0.001) post-injury. (C) L-cLUSS (F = 19.503, p < 0.001) indicated an increase in minor PBLI at 0.5 h (p = 0.048) and 3 h (p = 0.012) post-injury compared to pre-injury levels. Moderate PBLI demonstrated higher ultrasonographic scores at 3 h (p = 0.006), 6 h (p = 0.003), 12 h (p = 0.003), and 24 h (p < 0.001) post-injury. Serious and severe PBLI also showed elevated ultrasonographic scores at 0.5 h (p < 0.002), 3 h (p < 0.001), 6 h (p < 0.001), 12 h (p < 0.001), and 24 h (p < 0.001) post-injury. *p < 0.05, †p < 0.01, $p < 0.001. Comparisons were made using RM ANOVA between groups at each time point post-injury vs. pre-injury (Friedman test).

Fig. 5

Linear regression analyses of cLUSS and PO₂. Afte0.5 h r (A), 3 h (B), 6 h (C), 12 h (D), 24 h (E). Strong negative correlations of cLUSS with PO₂ within 24 h post-injury. *Solid line represents linear regression between cLUSS with the PO₂. Dash lines indicate 95% confidence intervals.

Fig. 6

Linear regression analyses of cLUSS and AaDO₂. After 0.5 h (A), 3 h (B), 6 h (C), 12 h (D), 24 h (E). Strong positive correlations of cLUSS with AaDO₂ within 24 h post-injury. *Solid line represents linear regression between cLUSS with the AaDO₂. Dash lines indicate 95% confidence intervals.

Fig. 7

Consistency Analysis of Bilateral Lung Ultrasound Scores. (A & B) Linear regression analyses of the gradient between R-cLUSS and L-cLUSS after 0.5 h, A Bland–Altman analysis showed the mean bias was 2.625 ± 2.871. (C & D) Linear regression analyses of the gradient between R-cLUSS and L-cLUSS after 3 h, A Bland–Altman analysis showed the mean bias was 2.429 ± 2.925. (E & F) Linear regression analyses of the gradient between R-cLUSS and L-cLUSS after 6 h, A Bland–Altman analysis showed the mean bias was 2.667 ± 3.12. (G & H) Linear regression analyses of the gradient between R-cLUSS and L-cLUSS after 12 h, A Bland–Altman analysis showed the mean bias was 1.95 ± 2.481. (L & M) Linear regression analyses of the gradient between R-cLUSS and L-cLUSS after 24 h, A Bland–Altman analysis showed the mean bias was 3.1 ± 2.989. *Solid line represents linear regression between cLUSS with the AaDO₂. Dash lines indicate 95% confidence intervals.

Fig. 8

Predictive Efficiency Analysis of Lung Ultrasound. (A) Predictive efficiency of lung ultrasound within 24 h for moderate PBLI. (B) Predictive efficiency of lung ultrasound within 24 h for serious and sever PBLI. (C) Predictive efficiency of lung ultrasound at 0.5 h post-PBLI for predicting 24-hour mortality.