Daniele Medico

Objective: To evaluate the relationship between the lung ultrasound score (LUSS) and oxygenation indices. Design: Retrospective study from January 2022 to December 2023. Setting: Private veterinary center. Animals: A total of 56 examinations from 42 dogs were used for the analysis. Interventions: None. Measurements and Main Results: Arterial blood gas analysis was performed on room air. By summing the score assigned to eight quadrants, a LUSS was created that ranged from 0/24 for fully aerated lungs to 24/24 for nonaerated lungs. Represented conditions included pneumonia ( n = 25), cardiogenic pulmonary edema (CPE; 14), pulmonary hypertension (6), systemic or extrathoracic diseases (5), lung contusion (3), and pulmonary thromboembolism (3). The LUSS had a moderate correlation with oxygenation indices, showing a negative relationship with the ratio between arterial partial pressure of oxygen and fraction of inspired oxygen (PaO ₂ :FiO ₂ ): r = −0.79 (95% confidence interval [CI]: −0.87 to −0.662; p < 0.001) and a positive relationship with the alveolar‐arterial gradient (Grad(A‐a)O ₂ ): r = 0.68 (95% CI: 0.502–0.797; p < 0.001). In pneumonia, this correlation was moderate with an r of −0.61 (95% CI: −0.809 to −0.28; p = 0.001), while in CPE, it was very strong, with r = −0.81 (95% CI: −0.938 to −0.49; p < 0.001). The relationship between the LUSS and the Grad(A‐a)O ₂ was weaker, with r = 0.48 (95% CI: 0.111–0.738; p = 0.014) for pneumonia and 0.6 (95% CI: 0.105–0.858; p = 0.023) for CPE. The correlation between the PaO ₂ /FiO ₂ ratio and the Grad(A‐a)O ₂ was very strong, with r = −0.89 (95% CI: −0.934 to −0.817; p < 0.001). Conclusions: This study found a strong correlation between the LUSS and pulmonary oxygenation indices, suggesting that the LUSS is an effective tool for stratifying the severity of lung aeration loss and investigating respiratory status in healthy dogs as well as those with respiratory failure.

Background: Lung ultrasound (LUS) is a noninvasive tool for examining respiratory distress patients. The lung ultrasound score (LUSS) can be used to quantify and monitor lung aeration loss with good reliability. Hypothesis/Objectives: Assess the reliability of a new LUSS among raters with different levels of experience and determine how well the same raters agree on identifying patterns of LUS abnormalities. Animals: Forty LUS examinations of dogs and cats and 320 videos were reviewed from a digital database. Methods: Retrospective reliability study with post hoc analysis. Protocolized LUS were randomly selected; intrarater and interrater reliability of the LUSS and pattern recognition agreement among 4 raters with different levels of experience in LUS were tested. Results: The intrarater intraclass correlation coefficient (ICC) single measurement, absolute agreement, and 2-way mixed effects model was 0.967 for the high-experience rater (H-Exp), 0.963 and 0.952 for the medium-experience raters (M-Exp-1; M-Exp-2), and 0.950 for the low-experience rater (L-Exp). The interrater ICC average measurement, absolute agreement, and 2-way random effects model among the observers was 0.980. The Fleiss' kappa (k) values showed almost perfect agreement (k = 1) among raters in identifying pleural effusion and translobar tissue-like pattern, strong agreement for A-lines (k = 0.881) and B-lines (k = 0.806), moderate agreement (k = 0.693) for subpleural loss of aeration, and weak agreement (k = 0.474) for irregularities of the pleural line. Conclusions and Clinical Importance: Our results indicate excellent intra- and interrater reliability for LUS scoring and pattern identification, providing a foundation for the use of the LUSS in emergency medicine and intensive care.