cardiopulmonary bypass (cpb) circuit setup for cardiac arrest and resuscitation in pediatric animal model

Extracorporeal Cardiopulmonary Resuscitation in Animal Model After Cardiac Arrest

Congenital heart disease (CHD) is the most prevalent congenital malformation, with about one million births impacted&#160;worldwide per year1. Though modern advances in cardiothoracic surgery (CTS) and intensive care treatment have improved mortality rates, comorbidities remain extremely common2,3,4,5. Neurodevelopmental abnormalities, including cognitive and motor impairments as well as learning disabilities, are reported in around 25%-50% of these patients6,7,8. Surgery during the first days of life, especially those that require circulatory and cardiac arrest (CA), has been demonstrated to increase morbidity9. Hemodynamic alterations during surgery may have an important effect on the vulnerable developing newborn brain. Experimental models are essential to better understand the origin of these abnormalities and investigate neuroprotective strategies to improve the prognoses of these patients.
The use of animal models to study this population has been widely documented5,10,11,12,13,14. Notably, piglets offer an excellent option, given close approximations in cardiac anatomy (Figure 1), genome, and physiology, as well as their relatively larger size in comparison to other animal models15 (Figure 2). The use of piglet models to study the effects of both cardiopulmonary bypass (CPB) and CA has been previously described. These experimental animal models are useful for studying hemodynamic changes and associated end-tissue organ complications14,16,17,18,19,20. These models were developed to allow researchers to study human conditions in a controlled setting, with flexibility for a variety of experimental conditions. Most studies report the use of central cannulation, a technique that demands advanced surgical skills, requires higher resource utilization, and makes it difficult to ensure long-term survival. Though previous studies have documented the use of piglets in studying CPB12,15, few have proposed the peripheral cannulation technique.
This new peripheral cannulation technique is easier, less aggressive, and more feasible when compared to other published studies19. Moreover, validating this technique in newborns and small animals is novel and should be considered for use by all researchers interested in using an animal model to study CHD and its associated comorbidities. It is particularly appropriate for individuals with access to a laboratory equipped with supplies, resources, and personnel experienced in conducting animal model experiments.
In summary, the main aim of this study is to describe and validate a neonatal piglet model of CPB with CA. The protocol aims to study severe brain damage and other possible complications of CPB surgery in a controlled setting with varying experimental conditions. This method provides a model that is generalizable, reliable, and of high quality, which can be used for a wide variety of experimental protocols.

Author Spotlight: Simulating Pediatric Cardiac Surgery Using a Neonatal Piglet Model

Pediatric Animal Model of Extracorporeal Cardiopulmonary Resuscitation After Prolonged Circulatory Arrest

Mortality rates for children with congenital heart defects have improved significantly in recent years given improvements in cardiac surgery. However, comorbidities remain extremely common, and that's the goal of our lab. We aim to investigate these comorbidities, uncover underlying causes, and develop preventative measures.Right now, we are studying neuro abnormalities that develop after cardiac surgery. This protocol offers a feasible and reproducible animal model of simulating pediatric cardiac surgery. So with that, researchers can use it as a base to test many different experimental conditions and a wide variety of other hypotheses.The peripheral cannulation technique for porcine cardiopulmonary bypass in our model is both practical and cost effective. Furthermore, it does allow a more reliable way to assess postoperative outcomes than the traditional central cannulation technique. The flexibility of our model encourages future work in congenital heart disease and comorbidity studies.For example, our lab is currently planning to expand this model to study real-time monitoring of cerebral parameters such as oxygenation status and cerebral blood flow.

Cardiopulmonary Bypass (CPB) Circuit Setup for Cardiac Arrest and Resuscitation in Pediatric Animal Model

To begin, place the four-to-six-days-old anesthetized piglet in the dorsal recumbent position. After performing orotracheal intubation using a cuffed tube, auscultate the lung bases to confirm appropriate endotracheal tube placement. Set up mechanical ventilation and continuously monitor the depth of anesthesia during surgery through heart rate, blood pressure, and oxygen saturation.Adjust ventilatory and sedation parameters as required. Then insert a 3 French catheter in the femoral artery, followed by a 4 French catheter in the vein. Next, initiate the cardiopulmonary bypass, or CPB, circuit set up by shortening the CPB tubing while maintaining enough distance between the animal and the machine.Create a tubing bridge to connect the membrane oxygenator outflow and pump inflow. Once all the connection points are sealed, sweep the circuit with 300 microliters of heparin saline solution and 300 milliliters of fresh donor pig blood, followed by sodium bicarbonate, heparin, and calcium gluconate. Once the CPB circuit is ready, expose the left internal jugular vein, and insert the needle catheter into it.Similarly, expose the right carotid artery to prepare for cannulation. Once a blood flash is visible, carefully insert a guide wire into the vessel. Thread a dilator over the wire and into the vessel.Then remove the dilator. Slowly thread an 8 French venous cannula approximately four centimeters into the vessel, and remove the wire, ensuring the cannula remains in place. Then place a 6 French pediatric arterial cannula into the right carotid artery as previously demonstrated with dilation.Finally, administer an intravenous heparin bolus through the newly placed arterial cannula. After achieving access, use 3-0 absorbable sutures to fix both cannulas to the animal, and tape to prevent inadvertent removal. Connect the cannulas to the CPB circuit, ensuring heparin saline is added to the connection points to prevent air in the circuit.Set the initial flow to 80 to 85 milliliters per kilogram per minute. To induce cardiac arrest, administer nine milliequivalents of potassium chloride. Once the heart is stopped, isolate the animal from the circuit.Then maintain the CPB circuit flow to circulate at 1, 500 RPM. After achieving appropriate cardiac arrest conditions, begin extracorporeal cardiopulmonary resuscitation by reconnecting the piglet to the CPB circuit. Administer three milliliters of calcium gluconate and six milliliters of sodium bicarbonate through peripheral arterial access, adding doses as necessary.The vessel cannulation and CPB with cardiac arrest achieved a 92%success rate in the experiments. MRIs demonstrated clear signs of early brain damage in the CPB with cardiac arrest animals compared to control. The acute diffusion tensor imaging modality better identified the signs of infarction than other conventional MRI sequences.

Research

JoVE Journal

Medicine

Congenital heart disease (CHD) is the most prevalent congenital malformation, with about one million births impacted worldwide per year. Comprehensive ...