Search

Simple Summary: Cardiac output (CO) measurement devices are classified as invasive, minimally invasive, or noninvasive depending on their level of invasiveness for CO data acquisition. Pulmonary artery thermodilution is the 'gold standard' CO technique. This method is more accurate, but its invasiveness possesses risks. Minimally invasive lithium dilution (LiD) is slowly replacing thermodilution as a reference standard in animal research due to its excellent agreement and acceptable performance. Monitoring CO with standard cardiovascular parameters (i.e., blood pressure and heart rate) in anesthetized animals can potentially improve patient care and case outcomes. Hence, we evaluated noninvasive electrical cardiometry (EC)-measured CO and other EC-acquired hemodynamic variables, and analyzed them against CO measured using LiD in healthy, anesthetized dogs during different treatments (dobutamine, esmolol, phenylephrine, and high-dose isoflurane) impacting CO values. Overall, EC showed good agreement with LiD, but it exhibited consistent underestimation when the CO values were higher. The percentage error was low and within published standards, and a good trending pattern was exhibited by EC. The acquired EC variables followed the trends in CO obtained by LiD. EC may be a pivotal tool for monitoring trends in hemodynamics and guiding treatments for cardiovascular anesthetic complications in clinical settings. Numerous cardiac output (CO) technologies were developed to replace the 'gold standard' pulmonary artery thermodilution due to its invasiveness and the risks associated with it. Minimally invasive lithium dilution (LiD) shows excellent agreement with thermodilution and can be used as a reference standard in animals. This study evaluated CO via noninvasive electrical cardiometry (EC) and acquired hemodynamic variables against CO measured using LiD in six healthy, anesthetized dogs administered different treatments (dobutamine, esmolol, phenylephrine, and high-dose isoflurane) impacting CO values. These treatments were chosen to cause drastic variations in CO, so that fair comparisons between EC and LiD across a wide range of CO values (low, intermediate, and high) could be made. Statistical analysis included linear regression, Bland–Altman plots, Lin's concordance correlation coefficient (ρc), and polar plots. Values of p < 0.05 represented significance. Good agreement was observed between EC and LiD, but consistent underestimation was noted when the CO values were high. The good trending ability, ρc of 0.88, and low percentage error of ±31% signified EC's favorable performance. Other EC-acquired variables successfully tracked changes in CO measured using LiD. EC may be a pivotal hemodynamic tool for continuously monitoring circulatory changes, as well as guiding and treating cardiovascular anesthetic complications in clinical settings. [ABSTRACT FROM AUTHOR]

Simple Summary: Using general anesthesia on animals causes significant changes to the heart and blood vessels that disrupt normal cardiovascular performance. Blood pressure (BP) is used for closely monitoring hemodynamics in anesthetized animals. However, BP is affected by various factors and may not always accurately correlate with the total body blood flow. Pulmonary artery thermodilution (PATD) is the gold standard for cardiac output (CO) measurements, but, due to the high risks associated with its invasiveness, it is not performed in clinical settings. This study evaluates noninvasive electrical cardiometry's (EC) performance in measuring CO and other hemodynamic variables in healthy anesthetized dogs during acute blood volume manipulation. The EC measurements consistently underpredict the CO values as compared with PATD, but have a better performance when acute blood loss occurs. Even though the EC readings have a slightly higher error than the accepted error, this method is very good at showing trends in the CO measured using PATD. Other EC-derived variables are able to closely track the changes in the CO measured using PATD. In clinics, noninvasive EC may benefit the patient care quality for anesthetized dogs by monitoring the trends in hemodynamics and guiding anesthetists to diagnose and treat cardiovascular complications. In animals, invasive pulmonary artery thermodilution (PATD) is a gold standard for cardiac output (CO) monitoring, but it is impractical in clinical settings. This study evaluates the agreement between PATD and noninvasive electrical cardiometry (EC) for measuring CO and analyzes the other EC-derived hemodynamic variables in six healthy anesthetized dogs subjected to four different hemodynamic events in a sequential order: (1) euvolemia (baseline); (2) hemorrhage (33% blood volume loss); (3) autologous blood transfusion; and (4) 20 mL/kg colloid bolus. The CO measurements obtained using PATD and EC are compared using Bland–Altman analysis, Lin's concordance correlation (LCC), and polar plot analysis. Values of p < 0.05 are considered significant. The EC measurements consistently underpredict the CO values as compared with PATD, and the LCC is 0.65. The EC's performance is better during hemorrhage, thus indicating its capability in detecting absolute hypovolemia in clinical settings. Even though the percentage error exhibited by EC is 49.4%, which is higher than the standard (<30%), EC displays a good trending ability. Additionally, the EC-derived variables display a significant correlation with the CO measured using PATD. Noninvasive EC may have a potential in monitoring trends in hemodynamics in clinical settings. [ABSTRACT FROM AUTHOR]

Background: Myxomatous mitral valve disease (MMVD) is more prevalent in Cavalier King Charles Spaniels (CKCSs) compared to dogs of other breeds at a given age. Abnormal valvular stress is thought to contribute to the development and progression of MMVD, and a relationship exists between mitral valve (MV) morphology and stress acting on the valve. Objectives: To determine whether the MV morphology of healthy adult CKCSs differs from the morphology of healthy adult dogs of other breeds determined by RT‐3DTTE. Animals Thirty‐five healthy CKCSs and 41 healthy dogs of other breeds. Methods: Prospective cross‐sectional study. Dogs underwent physical examination, conventional echocardiography, and RT‐3DTTE. RT–3DTTE datasets were analyzed using dedicated software for MV morphologic analysis. Morphologic variables were compared between CKCSs and dogs of other breeds. Results: The MV of healthy CKCSs had a smaller annulus height (0.46 ± 0.11 vs. 0.56 ± 0.17; P =.0021), tenting height (0.26 ± 0.12 vs. 0.42 ± 0.18; P <.001), tenting area (0.42 ± 0.15 vs. 0.79 ± 0.34; P <.001), normalized tenting volume (0.09 [0.05–0.13] vs. 0.14 [0.10–0.20]; P <.001), and normalized area of the posterior leaflet (0.57 ± 0.15 vs. 0.66 ± 0.18; P =.016) compared to healthy dogs of other breeds; this results in CKCSs having a flatter MV with reduced tenting, compared to the MV of other breeds. Conclusions and Clinical Importance: These morphologic features could confer a mechanical disadvantage and play a role in the predisposition of CKCSs to the early development of MMVD. [ABSTRACT FROM AUTHOR]

Simple Summary: Assessing enlargement of the left atrium (one of the four cardiac chambers) is extremely important for gaining information about dogs' heart disease, their prognosis, and directing treatment. However, people with different levels of experience may be required to make this assessment, and we don't know how observers with different experiences perform in making this assessment. In this study, five observers with different levels of experience evaluated the left atrium of 36 dogs in a blinded fashion (i.e., unaware of each other measurements, or of the identity of the dog), compared to two cardiologists. We then used statistical analysis to evaluate repeatability, reproducibility, accuracy of the measurements, and the capacity of correctly identifying left atrial enlargement. We found that the measurements performed by observers with more experience where more similar to the cardiologists' measurements, and that combining more than one technique for measuring the left atrium can improve accuracy of the identification of left atrial enlargement. Assessment of left atrial (LA) sizes in dogs informs clinical staging, risk assessment, treatment decisions, and prognosis. The objective of this study was to assess the diagnostic performance of observers with different levels of experience measuring the LA with three different techniques. Echocardiographic images from 36 dogs with different degrees of left atrial enlargement (LAE) were retrospectively retrieved, anonymized and measured in a blinded fashion by a veterinary student, a first-year cardiology resident, a third-year cardiology resident, and two board-certified veterinary cardiologists. The LA to aortic root ratio (LA:Ao), LA antero-postero diameter indexed to body weight (LAiAPD) and left atrial area were measured. Inter- and intra-observer intraclass correlation coefficients (ICCs) were calculated for all three variables. Bland–Altman plots and accuracy in identification of LAE were calculated for the three least experienced observers using LA:Ao and LAiAPD. Intra- and interobserver ICCs were greater than 0.9 for every variable. The observer with least experience had significant positive bias and a tendency to overestimate larger measurements using LA:Ao, but not using LAiAPD. The accuracy of identification of LAE also increased with the increasing level of experience and was higher for LAiAPD compared to LA:Ao. Combining both methods for identification of LAE, further increased accuracy. [ABSTRACT FROM AUTHOR]

To demonstrate if modified passive leg raise (PLR M) maneuver can be used for volumetric evaluation of fluid responsiveness (FR) by inducing cardiac output (CO) changes during experimental induction and correction of hypovolemia in healthy anesthetized dogs. The effects of PLR M on plethysmographic variability index (PVI) and pulse pressure variation (PPV) were also investigated. Prospective, crossover study. A total of six healthy anesthetized Beagle dogs. Dogs were anesthetized with propofol and isoflurane. They were mechanically ventilated under neuromuscular blockade, and normothermia was maintained. After instrumentation, all dogs were subjected to four stages: 1, baseline; 2, removal of 27 mL kg–1 circulating blood volume; 3, after blood re-transfusion; and 4, after 20 mL kg–1 hetastarch infusion over 20 minutes. A 10 minute stabilization period was allowed after induction of each stage and before data collection. At each stage, CO via pulmonary artery thermodilution, PVI, PPV and cardiopulmonary variables were measured before, during and after the PLR M maneuver. Stages were sequential, not randomized. Statistical analysis included repeated measures anova and Tukey's post hoc test, considering p < 0.05 as significant. During stage 2, PLR M at a 30° angle significantly increased CO (mean ± standard deviation, 1.0 ± 0.1 to 1.3 ± 0.1 L minute–1; p < 0.001), with a simultaneous significant reduction in PVI (38 ± 4% to 21 ± 4%; p < 0.001) and PPV (27 ± 2% to 18 ± 2%; p < 0.001). The PLR M did not affect CO, PPV and PVI during stages 1, 3 and 4. In anesthetized dogs, PLR M at a 30° angle successfully detected FR during hypovolemia, and identified fluid nonresponsiveness during normovolemia and hypervolemia. Also, in hypovolemic dogs, significant decreases in PVI and PPV occurred in response to PLR M maneuver. [ABSTRACT FROM AUTHOR]