Effect of body position on intra-abdominal pressures and abdominal perfusion pressures measured at three sites in horses anesthetized with short-term total intravenous anesthesia.

OBJECTIVE: To assess effects of body position on direct measurements of intra-abdominal pressure (IAP) and abdominal perfusion pressure (APP) in horses anesthetized with total intravenous anesthesia (TIVA). ANIMALS: 9 healthy adult horses. PROCEDURES: Instrumentation in unsedated standing horses involved insertion of an arterial catheter for blood pressure measurements and 3 intraperitoneal cannulas (left flank, right flank, and ventral abdomen) for IAP measurements. Baseline values were measured for heart rate, respiratory rate, systolic arterial blood pressure, mean arterial blood pressure (MAP), diastolic arterial blood pressure, and IAP. Horses were medicated with xylazine, and pressures were measured again. Anesthesia was induced with ketamine-diazepam and maintained with a ketamine-guaifenesin infusion. Horses were positioned twice into left lateral recumbency, right lateral recumbency, or dorsal recumbency. Hemodynamic pressures and accessible abdominal pressures were measured for each recumbency position. The APP was calculated as MAP - IAP. Differences in IAP, MAP, APP and sedation (standing horses) or body position (anesthetized horses) were compared by means of repeated-measures ANOVA or paired t tests. RESULTS: Baseline hemodynamic and IAPs were not different after xylazine administration. Ventral abdomen IAP and MAP were lower for horses in dorsal recumbency than in right or left lateral recumbency. Ventral abdomen APP remained unchanged. For lateral recumbencies, flank IAP was lower and APP was higher than pressure measurements at the same sites during dorsal recumbency. CONCLUSIONS AND CLINICAL RELEVANCE: Body position affected IAP and APP in healthy anesthetized horses. These effects should be considered when developing IAP acquisition methods for use in horses with abdominal disease

Development of a likelihood of survival scoring system for hospitalized equine neonates using generalized boosted regression modeling.

BACKGROUND: Medical management of critically ill equine neonates (foals) can be expensive and labor intensive. Predicting the odds of foal survival using clinical information could facilitate the decision-making process for owners and clinicians. Numerous prognostic indicators and mathematical models to predict outcome in foals have been published; however, a validated scoring method to predict survival in sick foals has not been reported. The goal of this study was to develop and validate a scoring system that can be used by clinicians to predict likelihood of survival of equine neonates based on clinical data obtained on admission. METHODS AND RESULTS: Data from 339 hospitalized foals of less than four days of age admitted to three equine hospitals were included to develop the model. Thirty seven variables including historical information, physical examination and laboratory findings were analyzed by generalized boosted regression modeling (GBM) to determine which ones would be included in the survival score. Of these, six variables were retained in the final model. The weight for each variable was calculated using a generalized linear model and the probability of survival for each total score was determined. The highest (7) and the lowest (0) scores represented 97% and 3% probability of survival, respectively. Accuracy of this survival score was validated in a prospective study on data from 283 hospitalized foals from the same three hospitals. Sensitivity, specificity, positive and negative predictive values for the survival score in the prospective population were 96%, 71%, 91%, and 85%, respectively. CONCLUSIONS: The survival score developed in our study was validated in a large number of foals with a wide range of diseases and can be easily implemented using data available in most equine hospitals. GBM was a useful tool to develop the survival score. Further evaluations of this scoring system in field conditions are needed

Probability of survival for the total survival score in hospitalized foals.

<p>Probability of survival for the total survival score in hospitalized foals.</p

Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) of FSS to predict survival, and survival rate, SS, and FSS for each season in the prospective study.

<p>SS, sepsis score; FSS, foal survival score; *median and range.</p><p>Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) of FSS to predict survival, and survival rate, SS, and FSS for each season in the prospective study.</p

Univariate logistic regression for survival in hospitalized foals from the prospective study.

<p>**P<0.01.</p><p>FSS, foals survival score.</p><p>Univariate logistic regression for survival in hospitalized foals from the prospective study.</p

Admission laboratory, clinical and historical variables categorized by outcome in neonatal foals from the retrospective study.

<p>Data expressed as median and range. A P value<0.05 was considered significant.</p><p>y, yes; n, no; bpm, beats/breaths per minute; h, hours.</p><p>Admission laboratory, clinical and historical variables categorized by outcome in neonatal foals from the retrospective study.</p

Receiver operating characteristic (ROC) curve for FSS to predict survival in the prospective study.

<p>A cutoff value of 4 for FSS maximized sensitivity (96%) and specificity (71%) to predict survival in hospitalized foals. AUC, area under the curve; FSS, foal survival score.</p

Survival score in hospitalized neonatal foals^*

<p>*Note: The original scale derived from the GLM output ran from −3.5 to +3.5. The score was rescaled to range from 0 to 7; for example, Prematurity was originally coded as −1 (no) and 0 (yes). Because of this rescaling, it was necessary to calculate probability of survival as:</p><p>, where x is the survival score.</p><p>Survival score in hospitalized neonatal foals^{<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0109212#nt104" target="_blank">*</a>}</p