CT validation of SVC-RA junction location for pediatric central line placement: is vertebral bodies below the carina accurate?

PURPOSE: The key landmark for tip position of a central venous catheter (CVC) is the SVC-RA junction. In adults, localization of the SVC-RA junction may be assessed as a function of vertebral body units (VBU) below the carina during CVC placement. We investigated the relationship between the SVC-RA junction and the carina in children. MATERIALS AND METHODS: 584 CT scans of 0-18 years were analyzed. The carina was marked automatically by software while the SVC-RA junction and vertebrae were marked manually. The SVC-RA junction to carina (JC) distance was the primary study measurement reported in both VBU and mm. RESULTS: The data show an average JC distance of 1.25 VBU for 0-1 year, 1.27 VBU for 1-4 years, 1.34 VBU for 4-9 years, 1.53 VBU for 9-15 years, and 1.64 VBU for 15-18 years. A positive relationship between weight and JC distance was also demonstrated. CONCLUSION: JC distance is a useful predictor of SVC-RA junction location in children. Significant relationships were shown between JC distance and both age and weight. Due to small differences between age groups, however, average JC distance for all comers (1.48 VBU, 95% CI 0.7 - 2.3) can be used for SVC-RA junction identification in CVC placement.

Ex Vivo Heart Perfusion for 72 Hours Using Plasma Cross Circulation.

Preservation of a donor heart for transplantation is limited to 6-8 hours. Based on our demonstration of 12 hour perfusion with plasma cross circulation, this study aimed to evaluate ex vivo heart perfusion (EVHP) for up to 72 hours using cross plasma circulation (XC-plasma) from a live, awake paracorporeal sheep (PCS). Six ovine hearts were perfused for 72 hours using plasma cross circulation at a rate of 1 L/min with a live, awake PCS. Controls were seven perfused hearts without cross circulation. Experiments were electively ended at 72 hours, and epinephrine (0.1 mg) was delivered to demonstrate hormonal responsiveness. All controls failed at 6-10 hours. All six hearts perfused for 72 hours maintained normal heart function, metabolism, and responsiveness to epinephrine. Blood gases, electrolytes, and lactate levels were normal and stable throughout the study. All hearts appeared suitable for transplantation. We have demonstrated successful normothermic EVHP for 72 hours.

Achieving 12 Hour Normothermic Ex Situ Heart Perfusion: An Experience of 40 Porcine Hearts.

Although total body perfusion with extracorporeal life support (ECLS) can be maintained for weeks, individual organ perfusion beyond 12 hours has yet to be achieved clinically. Normothermic ex situ heart perfusion (ESHP) offers the potential for prolonged cardiac preservation. We developed an ESHP system to study the effect of perfusate variables on organ preservation, with the ultimate goal of extending organ perfusion for ≥24 hours. Forty porcine hearts were perfused for a target of 12 hours. Hearts that maintained electromechanical activity and had a <3× increase in vascular resistance were considered successful preservations. Perfusion variables, metabolic byproducts, and histopathology were monitored and sampled to identify factors associated with preservation failure. Twenty-two of 40 hearts were successfully preserved at 12 hours. Successful 12 hour experiments demonstrated lower potassium (4.3 ± 0.8 vs. 5.0 ± 1.2 mmol/L; p = 0.018) and lactate (3.5 ± 2.8 vs. 4.5 ± 2.9 mmol/L; p = 0.139) levels, and histopathology revealed less tissue damage (p = 0.003) and less weight gain (p = 0.072). Results of these early experiments suggest prolonged ESHP is feasible, and that elevated lactate and potassium levels are associated with organ failure. Further studies are necessary to identify the ideal perfusate for normothermic ESHP.