Caudal vena cava measurements and fluid responsiveness in hospitalized cats with compromised hemodynamics and tissue hypoperfusion.

OBJECTIVE: To evaluate the use of the caudal vena cava collapsibility index (CVCCI) and the inspiratory/minimum and expiratory/maximum diameters of the vena cava to predict fluid responsiveness in hospitalized, critically ill cats with hemodynamic and tissue perfusion abnormalities. DESIGN: Diagnostic test study in a prospective cohort of hospitalized cats. SETTING: Private practice referral hospital. ANIMALS: Twenty-four hospitalized cats with spontaneous breathing and compromised hemodynamics and tissue hypoperfusion. INTERVENTIONS: Ultrasonographic examination before and after fluid expansion with 10 ml/kg of lactated Ringer's solution. MEASUREMENTS AND MAIN RESULTS: Fluid responsiveness was evaluated using the velocity-time integral (VTI) of the subaortic blood flow, by measuring it before and after a fluid load of 10 ml/kg of lactated Ringer's solution. The CVCCI was calculated using the following formula: (maximum diameter - minimum diameter / maximum diameter) × 100. Ten cats were fluid responders (42 %) and 14 were nonresponders (58 %). The area under the receiver operating characteristic curve (AUROC) with their 95% confidence interval for the predictors and the best cutoff values were as follows: CVCCI, AUROC = 0.83 (0.66-1.00) and cutoff = 31%; inspiratory/minimum diameter, AUROC = 0.86 (0.70-1.00) and cutoff = 0.24 cm; expiratory/maximum diameter, AUROC = 0.88 (0.74-1.00) and cutoff = 0.22 cm. A significant lineal correlation was observed between the percentage of increase in VTI after expansion and CVCCI (rs  = 0.68, P < 0.001), expiratory/maximum diameter (rs  = -0.72, P < 0.001), and inspiratory/minimum diameter (rs  = -0.71, P < 0.001). The intraobserver and interobserver variability was low for VTI, and the expiratory/maximum diameter and inspiratory/minimum diameter were high for CVCCI. CONCLUSIONS: Caudal vena cava measurements could be useful to predict the response to fluids in hospitalized cats with hemodynamic and tissue perfusion alterations. Additional studies are required to draw definitive conclusions about the role of these variables to guide fluid administration in cats.

Echocardiographic indicators of fluid responsiveness in hospitalized dogs with compromised hemodynamics and tissue hypoperfusion.

OBJECTIVE: To evaluate the accuracy of selected echocardiographic variables used to predict fluid responsiveness in hospitalized dogs with compromised hemodynamics and tissue hypoperfusion. DESIGN: Diagnostic test study in a prospective cohort of hospitalized dogs. SETTING: Veterinary referral clinics. ANIMALS: Forty-four hospitalized dogs with compromised hemodynamics and tissue hypoperfusion were utilized in this study. INTERVENTIONS: Echocardiographic examination before and after fluid replacement with 30 ml/kg of lactated Ringer's solution. MEASUREMENTS AND MAIN RESULTS: Pre-fluid replacement measurements of velocity of transmitral E wave (E-peak), the left ventricular end-diastolic internal diameter normalized to body weight (LVIDdN), and the left ventricular end-systolic internal diameter normalized to body weight (LVIDsN) were significantly lower in fluid-responsive patients compared with nonresponders (P < 0.001). The area under the receiver operating characteristic curve (AUROC) with its 95% confidence interval (CI) for each significant predictor was as follows: E-peak 0.907 (0.776-1.000, P < 0.001) and LVIDdN 0.919 (0.801-1.000, P < 0.001). The predictive capacity of LVIDsN was not significantly better than chance (AUROC, 0.753; 95% CI, 0.472-1.000, P = 0.078). A significant negative linear correlation was observed between the percentage of increase in velocity-time integral after expansion and the echocardiographic variables LVIDdN (rs  = -0.452, P = 0.023) and E-peak (rs  = -0.396, P = 0.008) pre-fluid replacement. The intraobserver and interobserver variability was very low (<5 %) for all measurements. CONCLUSIONS: In this study using critically ill dogs with compromised hemodynamics and tissue hypoperfusion, pre-fluid replacement measurements of LVIDdN and E-peak adequately predict fluid responsiveness. Because a small number of fluid nonresponders were involved in the present study (11.4%), further studies that include larger numbers of fluid-nonresponsive animals are required.

Retrospective evaluation of jugular venous blood variables and mortality in critically ill hospitalized cats.

OBJECTIVE: To evaluate clinicopathological variables associated with hospital mortality in critically ill cats with compromised hemodynamics and tissue hypoperfusion. DESIGN: Retrospective observational study. SETTING: Private referral center. ANIMALS: Fifty-seven critically ill cats with compromised hemodynamics or tissue hypoperfusion. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The electronic medical records were searched for all cats admitted from June 2014 to November 2020. Cats were included in the study if the medical records clearly identified the presence of compromised hemodynamics and tissue hypoperfusion. Blood samples were obtained by percutaneous puncture of the external jugular vein, and blood gases, electrolytes, L-lactate concentration, and glucose were measured by a point-of-care analyzer. A predictive logistic regression model for mortality was performed. A total of 57 cats were ultimately included in the study. Thirty-five cats died. Eighteen of them were euthanized because of the severity of illness, and 17 died naturally. Twenty-two cats were discharged alive from the hospital. After adjusting for the Acute Patient Physiologic and Laboratory Evaluation (APPLE) fast score and disease category, jugular venous partial pressure of oxygen (Pvjo2 ) and HCT at admission were independent predictors of hospital mortality (HCT: odds ratio [OR], 0.763, 95% confidence interval [CI]: 0.625-0.930; P = 0.008; Pjvo2 : OR, 0.858; 95% CI: 0.749-0.984; P = 0.029). The association of these variables with mortality was maintained after conducting a sensitivity analysis and excluding cats that died by euthanasia. CONCLUSIONS: In cats with hemodynamic instability and tissue hypoperfusion, HCT and Pvjo2 behaved as independent predictors of mortality. Both variables seem to reflect the magnitude of oxygen debt and tissue hypoperfusion.