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Objectives: Swine (Sus Scrofa) are utilized broadly in research settings, given similarities to human vessel size and function; however, there are some important differences for clinicians to understand in order to interpret and perform translational research. This review article uses angiograms acquired in the course of a translational research program to present a description of the functional anatomy of the swine. Methods: Digital subtraction angiography and computed tomography angiography were obtained throughout the course of multiple studies utilizing power injection with iodinated contrast. Subtracted two-dimensional images and three-dimensional multiplanar reformations were utilized post image acquisition to create maximal intensity projections and three-dimensional renderings of using open-source software (OsiriX). These imaging data are presented along with vessel measurements for reference. Results: An atlas highlighting swine vascular anatomy, with an emphasis on inter-species differences that may influence how studies are conducted and interpreted, was compiled. Conclusions: Swine are utilized in broad-reaching fields for preclinical research. While many similarities between human and swine vasculature exist, there are important differences to consider when conducting and interpreting research. This review article highlights these differences and presents accompanying images to inform clinicians gaining experience in swine research. [ABSTRACT FROM AUTHOR]

Perfusion of the brain is critical, but this can be compromised due to focal space occupying lesions (SOL). SOLs can raise intracranial pressure (ICP), resulting in reduced cerebral blood flow (CBF). Most gyrencephalic models of brain injury focus on parenchymal injury, with few models of acutely elevated ICP. We hypothesized that we could employ a SOL technique to develop a titratable ICP model and sought to quantitate the resulting decrease in brain perfusion. Six swine were anesthetized and instrumented. A Fogarty balloon catheter was inserted intracranially. Blood CO 2 partial pressure was maintained between 35 and 45 mmHg. The Fogarty balloon was infused with normal saline at 1 mL/min to ICP targets of 10, 20, 30, and 40 mmHg. CBF (mL/100 g/min) were assessed at each ICP level using computed tomography perfusion (CTP). Data are presented as the mean ± standard deviation with all pressures measured in mmHg. CBF values were compared between baseline and each ICP level using analysis of variance. Baseline ICP was 5 ± 2 and systolic blood pressure was 106 ± 7. Balloon volumes (mL) required to achieve each incremental ICP level were 2.4 ± 0.5, 4.9 ± 1.7, 7.6 ± 1.6, and 9.9 ± 1.7. CBF decreased with each raised ICP level, with CBF being significantly less than baseline at ICP values of 30 (56.1 ± 34.7 versus 20.6 ± 11.0, P < 0.05) and 40 (56.1 ± 34.7 versus 6.5 ± 10.6, P < 0.05). An intracranial balloon catheter can be used to increase ICP, delivering a proportionate reduction in CBF. This model can be used in the future studies to examine adjuncts that manipulate intracranial pressure and their effect on brain perfusion. [ABSTRACT FROM AUTHOR]

Aim: To evaluate the mean aortic-right atrial pressure (AoP-RAP) gradients and mean coronary perfusion pressures (CPPs) observed during open cardiac massage (OCM) versus those obtained with selective aortic arch perfusion (SAAP) in post-mortem hypovolemic swine.Methods: Post-mortum, male swine, utilized in prior studies of hemorrhage, were included in the study. Animals were bled ∼25-50% of circulating volume prior to death. Animals either underwent clamshell thoracotomy and OCM immediately after death was confirmed (n = 6) or underwent SAAP within 5-15 min of death (n = 6). Aortic root and right atrial pressures were recorded continuously during each method of resuscitation using solid state blood pressure catheters. Representative five beat samples were extracted; short, similarly timed segments of SAAP were also extracted. Mean AoP-RAP gradient and CPPs were calculated and compared.Results: Mean AoP-RAP gradient and CPP were significantly higher in SAAP animals compared to OCM animals (mean ± SD; 29.1 ± 8.4 vs. 24.5 ± 5.0, p < 0.001; 28.9 ± 8.5 vs. 9.9 ± 6.0, p < 0.001). Mean CPP was not significantly different from mean AoP-RAP gradient in SAAP animals (p = 0.92); mean CPP was significantly lower than mean AoP-RAP gradient in OCM animals (p < 0.001). While 97% of SAAP segments had a CPP > 15 mmHg, only 17% of OCM segments had a CPP > 15 mmHg (p < 0.001).Conclusion: SAAP appears to create a more favorable and efficient hemodynamic profile for obtaining ROSC when compared to OCM in this preclinical porcine study. [ABSTRACT FROM AUTHOR]

Background: In locations in which access to resuscitative therapy may be limited, treating polytraumatized patients present a challenge. There is a pressing need for adjuncts that can be delivered in these settings. To assess these adjuncts, a model representative of this clinical scenario is necessary. We aimed to develop a hemorrhage and polytrauma model in the absence of fluid resuscitation., Materials and Methods: This study consisted of two parts: pulmonary contusion dose-finding (n = 6) and polytrauma with evaluation of varying hemorrhage volumes (n = 6). We applied three, six, or nine nonpenetrating captive bolt-gun discharges to the dose-finding group and obtained computed tomography (CT) images. We segmented images to assess contusion volumes. We subjected the second group to tibial fracture, pulmonary contusion, and controlled hemorrhage of 20%, 30%, or 40% and observed for 3 hours or until death. We used Kaplan-Meier analysis to assess survival. We also assessed hemodynamic and metabolic parameters., Results: Contusion volumes for three, six, and nine nonpenetrating captive bolt-gun discharges were 24 ± 28, 50 ± 31, and 63 ± 77 cm3, respectively (p = .679). Animals receiving at least six discharges suffered concomitant parenchymal laceration, whereas one of two swine subjected to three discharges had lacerations. Mortality was 100% at 12 and 115 minutes in the 40% and 30% hemorrhage groups, respectively, and 50% at 3 hours in the 20% group., Conclusion: This study characterizes a titratable hemorrhage and polytrauma model in the absence of fluid resuscitation. This model can be useful in evaluating resuscitative adjuncts that can be delivered in areas remote to healthcare access., (2021.)

Swine are frequently used in medical research given their similar cardiac physiology to that of humans. Measuring cardiac parameters such as stroke volume and cardiac output are essential in this type of research. Contrast ventriculography, thermodilution, and pressure-volume loop (PV-loop) catheters can be used to accurately obtain cardiac performance data depending on which resources and expertise are available. For this study,five Yorkshire swine were anesthetized and intubated. Central venous and arterial access was obtained to place the necessary measurement instruments.A temperature probe was placed in the aortic root. A cold saline bolus was delivered to the right atrium and temperature deflection curve was recorded. Integration of the area under the curve allowed for the calculation of the current cardiac output.A pigtail catheter was percutaneously placed in the left ventricle and 30 mL of iodinated contrast was power injected over 2 seconds. Digital subtraction angiography images were uploaded to volumetric analysis software to calculate the stroke volume and cardiac output. A pressure volume-loop catheter was placed into the left ventricle (LV) and provided continuous pressure and volume data of the LV, which allowed the calculation of both stroke volume and cardiac output.All three methods demonstrated good correlation with each other. The PV-loop catheter and thermodilution exhibited the best correlation with a 3% error and a Pearson coefficient of 0.99, with 95% CI=0.97 to 1.1, (p=0.002). The PV-loop catheter against ventriculography also showed good correlation with a 6% error and a Pearson coefficient of 0.95, 95% CI=0.96 to 1.1 (p=0.01). Finally, thermodilution against ventriculography had a 2% error with r=0.95, 95% CI=0.93 to 1.11, (p=0.01). In conclusion, we state that the PV-loop catheter, contrast ventriculography, and thermodilution each offer certain advantages depending on the researcher's requirements. Each method is reliable and accurate for measuring various cardiac parameters in swine such as the stroke volume and cardiac output.

Hemorrhage constitutes the majority of potentially preventable deaths from trauma. There is growing interest in endovascular resuscitation techniques such as selective aortic arch perfusion (SAAP) for patients in cardiac arrest. This involves active perfusion of the coronary circulation via a thoracic aortic balloon catheter and is approaching clinical application. However, the technique is complex and requires refinement in animal models before human use can be considered. This paper describes a large animal model of exsanguination cardiac arrest treated with a bespoke SAAP system. Swine were anesthetized, instrumented and a splenectomy was performed before a controlled, logarithmic exsanguination was initiated. Animals were heparinized and the shed blood collected in a reservoir. Once cardiac arrest was observed, the blood was pumped through an extra-corporeal circuit into an oxygenator and then delivered through a 10 Fr balloon catheter placed in the thoracic aorta. This resulted in the return of a spontaneous circulation (ROSC) as demonstrated by ECG and aortic root pressure waveform. This model and accompanying SAAP system allow for standardized and reproducible recovery from exsanguination cardiac arrest.