Utility of point-of-care lung ultrasound for monitoring cardiogenic pulmonary edema in dogs

Point-of-Care Lung Ultrasound in Small Animal Emergency and Critical Care Medicine: A Clinical Review

Thoracic point-of-care ultrasound (T-POCUS) has grown in popularity and usage in small animal emergencies and critical care settings due to its non-invasive nature, mobility, and ability to acquire images in real time. This review summarizes current understanding about T-POCUS in dogs and cats with respiratory illnesses, including normal thoracic ultrasonography appearance and numerous pathological situations. The basics of T-POCUS are covered, including equipment, scanning procedures, and picture settings. Practical applications in patients with respiratory distress are discussed, with an emphasis on pleural space abnormalities and lung diseases. Ultrasound results define pulmonary disorders such as pneumonia, atelectasis, cardiogenic and non-cardiogenic pulmonary edema, lung lobe torsion, pulmonary fibrosis, pulmonary thromboembolism, pulmonary neoplasms, and pulmonary bleeding. The evaluation focuses on T-POCUS diagnostic skills in a variety of clinical settings. Limitations and the need for more study to standardize techniques, establish agreed terminology, and create specialized educational routes are highlighted.

Lung ultrasound for the diagnosis of subpleural consolidations - a review of the veterinary and human literature

Lung ultrasound (LUS) is an imaging modality of growing importance in human medicine. LUS has been extensively applied to human patients. Guidelines have been created for internal medicine, describing ultrasonographic features of various lung pathologic processes. Such guidelines do not exist for veterinary medicine, and studies on the utility of LUS in companion animals are limited. Therefore, this review compares conclusions from veterinary studies to recommendations in human medicine for the detection of subpleural consolidations beyond the application of LUS as a point-of-care modality in emergency and critical care.

Potential prognostic indicators in dogs with advanced heart failure secondary to myxomatous mitral valve disease

BACKGROUND

Advanced heart failure (AHF) secondary to myxomatous mitral valve disease (MMVD) in dogs has unclear predictive variables and survival time.

METHODS

This retrospective study included 38 dogs with AHF and 38 with stable congestive heart failure (CHF), both due to MMVD. Predictive variables for AHF were analysed, and survival times were calculated using logistic regression and the Kaplan-Meier method.

RESULTS

Left atrium to aortic root ratio, normalised left ventricular dimension at the end-diastole and end-systole, isovolumic relaxation time (IVRT) and early transmitral inflow velocity to IVRT ratio were associated with AHF progression. The median survival times were significantly longer in the stable group than in the AHF group. After AHF diagnosis, the median survival times for all-cause and cardiogenic mortality were 194 and 354 days, respectively.

LIMITATIONS

This was a single-centre retrospective observational study. The study population was small, with breed bias (overrepresentation of Maltese dogs). Additionally, the treatment plans depended on clinical experience.

CONCLUSIONS

AHF in dogs with CHF secondary to MMVD is linked to left heart chamber enlargement and increased left ventricular dimensions, significantly reducing survival time to around six months post-diagnosis. Early recognition and appropriate management may improve outcomes, highlighting the importance of advanced treatment strategies.

Lung Ultrasonography Does Not Distinguish between Interstitial and Alveolar Pulmonary Edema

For a long time, lung diseases have been considered the "forbidden zone" for ultrasound diagnosis because the lung is filled with gas, and the ultrasound waves are totally reflected when they encounter gas [...].

Lung ultrasound score in dogs and cats: A reliability study

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.

The Role of Point-of-Care Ultrasound in Managing Cardiac Emergencies

Point-of-care ultrasound (POCUS) is a useful imaging tool for the diagnosis and monitoring of cardiac emergencies. Unlike complete echocardiography, POCUS is a time-sensitive examination involving a subset of targeted thoracic ultrasound views to identify abnormalities of the heart, lungs, pleural space, and caudal vena cava. When integrated with other clinical information, POCUS can be helpful in the diagnosis of left-sided and right-sided congestive heart failure, pericardial effusion and tamponade, and severe pulmonary hypertension and can help clinicians monitor resolution or recurrence of these conditions.

Radiographic lung congestion scores in dogs with acute congestive heart failure caused by myxomatous mitral valve disease

BACKGROUND

In humans, lung congestion scores are predictive of recurrence of acute congestive heart failure (CHF) and are superior to cardiac biomarkers in predicting survival.

OBJECTIVES

The primary aim of this retrospective study was to determine if a modified lung congestion score (LCS) in dogs diagnosed with acute CHF because of myxomatous mitral valve disease was associated with time until recurrence or death.

ANIMALS

Complete medical records were available for a total of 94 dogs between 2010 and 2019, but only 35 dogs fulfilled the criteria for inclusion.

METHODS

This retrospective study used descriptive statistics to describe the cumulative and corrected LCS. Correlations were used to examine the association of the corrected LCS and time until recurrence or death, selected echocardiographic variables, and timing of furosemide administration.

RESULTS

The mean LCS was 8.4 (SD 3.3) and corrected LCS was 0.48 (SD 0.19). The pattern was predominantly symmetric (40% of dogs) and focal (caudal) but more commonly right-sided when asymmetric (40% vs 20%). The median number of days after initial diagnosis of acute CHF to readmission and death was 150 days (range 4-572), and 266 days (range 5-965), respectively. No significant association between the dog's corrected LCS and number of days until readmission (r = .173, P = .42) nor survival (r = .109, P = .56) was found. There was a negative significant correlation (r = -.71, P < .001) between the time interval of furosemide administration and corrected LCS.

Imaging and endoscopic diagnosis of lung diseases in small animals. A review

Diagnostic imaging plays a fundamental role in the diagnosis of pulmonary diseases. Radiography, ultrasound, computed tomography, and endoscopy are important tools for achieving a diagnosis. The choice of diagnostic procedure varies according to the patient, the suspected diagnosis and the risk/benefit ratio. Culture, cytology and histology are nearly always necessary to obtain a definitive diagnosis. Several biopsy sampling techniques are described. Surgical biopsies are the gold standard for the diagnosis of bronchiolitis or interstitial lung diseases but often not performed due to the high risk. In humans, the introduction of transbronchial cryobiopsies has led to excellent results in the study of interstitial lung diseases.

Integrated Basic Heart and Lung Ultrasound Examination for the Differentiation between Bacterial Pneumonia and Lung Neoplasm in Dogs—A New Diagnostic Algorithm

Simple Summary

Dyspnea is a highly alarming sign both for dog owners and veterinarians. Although its recognition is usually easy due to prominent suffering of an animal, finding its cause is challenging because many diseases of the heart, lungs, and airways may manifest themselves this way. Echocardiography and lung ultrasound allow for relatively quick and accurate identification of heart diseases. Dyspneic dogs without a heart and upper airway disease are usually suspected of either bacterial pneumonia or lung neoplasm. Although prognosis in these two conditions is diametrically different, differentiation between them is challenging. Chest radiography is performed in a lateral position, which is barely tolerated by a dyspneic dog, and intensive chest movements often make X-ray scans inconclusive. Computed tomography, although much more accurate, requires general anesthesia, which is difficult and potentially life-threating in a dyspneic dog. Therefore, lung ultrasound, which can be performed quickly in a conscious dog, standing or in sternal position, seems to be the method of choice. We develop and evaluate a diagnostic algorithm based on detection of three well-defined abnormalities in the lung ultrasound. The algorithm allows one to distinguish between bacterial pneumonia and lung neoplasm in a dyspneic dog with high probability of a conclusive result (91%) and high accuracy (>95%).

Abstract

The diagnostics of two of the most prevalent lung diseases in dogs, bacterial pneumonia (BP) and lung neoplasm (LN), are challenging as their clinical signs are identical and may also occur in extrapulmonary diseases. This study aims to identify ultrasonographic criteria and develop a lung ultrasound (LUS)-based diagnostic algorithm which could help distinguish between these two conditions. The study is carried out in 66 dyspneic dogs in which a heart disease was excluded using echocardiography. Based on imaging and laboratory diagnostic tests, as well as follow-up, the dogs are classified into LN (35 dogs) and BP (31 dogs) groups. LUS is performed at admission and the presence of seven lung abnormalities (pleural thickening, B-lines, subpleural consolidations, hepatization with or without aeration, nodule sign and mass classified together as a tumor, and free pleural fluid) and classification and regression trees are used to develop an LUS-based diagnostic algorithm. Distribution of all LUS abnormalities except for aerations differs significantly between groups; however, their individual differentiating potential is rather low. Therefore, we combine them in an algorithm which allows for definitive classification of 60 dogs (91%) (32 with LN and 28 with BP) with correct diagnosis of LN and BP in 31 dogs and 27 dogs, respectively.

Influence of concurrent lower respiratory tract disease on point-of-care lung ultrasound in small-breed dogs with myxomatous mitral valve disease

Background

Small‐breed dogs commonly have concurrent myxomatous mitral valve disease (MMVD) and lower respiratory tract disease (LRTD).

Hypothesis

Small‐breed dogs with preclinical MMVD and concurrent LRTD have more B‐lines on point‐of‐care lung ultrasound (POC‐LUS) compared to dogs without concurrent LRTD and are prone to misdiagnose as cardiogenic pulmonary edema (CPE).

Animals

A total of 114 small‐breed dogs with preclinical MMVD.

Methods

A prospective study was conducted, in which POC‐LUS was obtained and the number of B‐lines was calculated by a single clinician using the Veterinary Bedside Lung Ultrasound Examination protocol. The presence/absence of LRTD was assessed by clinicians blinded to the POC‐LUS results.

Results

Fifty and 64 dogs were in ACVIM stage B1 and B2, respectively. The presence of LRTD was prevalent in 74.6% (85/114) of small‐breed dogs with preclinical MMVD. When a previously reported criterion for CPE diagnosis (≥2 sites with >3 B‐lines/site) was applied, false‐positive results were observed in 15.8% (18/114) of dogs with preclinical MMVD. The summated number of B‐lines (3 vs. 1, P = .003), as well as the false‐positive rate (20% vs 3%, P = .04), were significantly higher in dogs with LRTD compared with dogs without LRTD. Multivariable logistic regression showed the presence of abnormalities other than B‐line on POC‐LUS (eg, thickened pleura or consolidation) could predict false‐positive results (odds ratio = 3.75, 95% confidence intervals 1.12‐12.54; P = .03) after adjustment for other clinical and echocardiographic factors.

Conclusions and Clinical Importance

Concurrent LRTD and abnormalities other than B‐lines should be considered in the interpretation of POC‐LUS in MMVD dogs.

Lung Ultrasound Fundamentals, "Wet Versus Dry" Lung, Signs of Consolidation in Dogs and Cats

Vet BLUE, a standardized and validated rapid lung ultrasound examination, includes 9 acoustic windows: 4 transthoracic bilaterally applied named Caudodorsal, Perihilar, Middle, and Cranial Lung Regions plus the Diaphragmatico-Hepatic view of AFAST/TFAST. Moreover, Vet BLUE has a B-line scoring system (weak positives-1, 2, and 3 and strong positives->3 and infinite) that semiquantitate degree of alveolar-interstitial syndrome and a visual lung language for signs of consolidation (Shred Sign [air bronchogram], Tissue Sign [hepatization], Nodule Sign, and Wedge Sign [pulmonary infarction]). Using its regional, pattern-based approach, a respiratory working diagnosis may be rapidly developed point-of-care and followed serially.

Global FAST for Patient Monitoring and Staging in Dogs and Cats

Please verify if FAST should be expanded at first use - "focused assessment with sonography for trauma"?: Global FAST consists of abdominal FAST, thoracic FAST, and Vet BLUE combined as a single point-of-care ultrasound examination used as an extension of the physical examination. By applying its unbiased set of 15 data imaging points, information is gained while avoiding image interpretation errors, such as satisfaction of search error and confirmation bias error, through selective POCUS imaging. Moreover, Global FAST is used for integrating information from both cavities, rapidly screening for the Hs and Ts of cardiopulmonary resuscitation, and staging localized versus disseminated disease, helpful diagnostically and prognostically for patient work-up. By seeing a problem list, patient care is improved.

Focused Cardiac Ultrasonography in Cats

Heart disease is a common cause of morbidity and mortality in cats. Focused cardiac ultrasonography (FCU) is a useful diagnostic tool for identifying heart disease in symptomatic and asymptomatic cats when performed by trained veterinarians. When used in conjunction with other diagnostics such as physical examination, blood biomarkers, electrocardiography, Global FAST, and other point-of-care ultrasonographic examinations, FCU may improve clinical decision making and help clinicians prioritize which cats would benefit from referral for complete echocardiography and cardiac consultation. This article reviews the definition, advantages, clinical indications, limitations, training recommendations, and a protocol for FCU in cats.

Comparison of curvilinear-array (microconvex) and phased-array transducers for ultrasonography of the lungs in dogs

OBJECTIVES

To compare the use of curvilinear-array (microconvex) and phased-array transducers for ultrasonographic examination of the lungs in dogs.

ANIMALS

13 client-owned dogs with left-sided congestive heart failure.

PROCEDURES

In a prospective methods comparison study, 24 ultrasonographic examinations of the lungs (4 sites/hemithorax) were performed with both curvilinear-array and phased-array transducers at 3 clinical time points. Two observers independently assessed the number of B lines (scored per site and in total), number of sites strongly positive for B lines (ie, those with > 3 B lines/site), and image quality (scored on a 5-point scale). Analyses included assessment of interobserver agreement with κ analysis, comparison of quality scores between transducers with mixed-effects modeling, and investigation of agreement and bias for B-line data and quality scores between transducers with Passing-Bablok regression.

RESULTS

Interobserver agreement for total B-line scores and number of strong-positive sites was excellent (κ > 0.80) for both transducers. There was no evidence of analytic bias for the number of B lines or strong-positive sites between transducers. Interobserver agreement for image quality scores was moderate (κ, 0.498 and 0.517 for the curvilinear-array and phased-array transducers, respectively). Both observers consistently assigned higher-quality scores to curvilinear-array images than to phased-array images.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated both curvilinear-array (microconvex) and phased-array transducers can be used by experienced sonographers to obtain diagnostic ultrasonographic images of the lungs in dogs with acute or resolving left-sided congestive heart failure and suggested the former transducer may be preferred, particularly to aid identification of anatomic landmarks for orientation.