Large Animal Model of Pumpless Arteriovenous Extracorporeal CO2 Removal Using Room Air via Subclavian Vessels

Abstract

End-stage lung disease (ESLD) causes progressive hypercapnia, dyspnea, and impacts quality of life. Many extracorporeal support (ECS) configurations for CO2 removal resolve symptoms but limit ambulation. An ovine model of pumpless ECS using subclavian vessels was developed to allow for ambulatory support. Vascular grafts were anastomosed to the left subclavian vessels in four healthy sheep. A low-resistance membrane oxygenator was attached in an arteriovenous (AV) configuration. Device function was evaluated in each animal while awake and spontaneously breathing, and while mechanically ventilated with hypercapnia induced. Sweep gas (FiO2=0.21) to the device was increased from 0-15 L/min and arterial and post-device blood gases, as well as post-device air, were sampled. Hemodynamics remained stable with average AV shunt flows of 1.34±0.14 L/min.. In awake animals, CO2 removal was 3.4±1.0 mL/kg/min at maximum sweep gas flow. Respiratory rate decreased from 60±25 at baseline to 30±11 breaths per minute. In animals with induced hypercapnia, PaCO2 increased to 73.9±15.1. At maximum sweep gas flow, CO2 removal was 3.4±0.4 mL/kg/min and PaCO2 decreased to 49.1±6.7 mmHg. Subclavian AV access is effective in lowering PaCO2 and respiratory rate, and is potentially an effective ambulatory destination therapy for ESLD patients.

Evaluation of Continuous Lactate Monitoring Systems within a Heparinized In Vivo Porcine Model Intravenously and Subcutaneously

“…Three methods were used to intervene the blood lactate and glucose level, as listed below: Intravenous Lactate Challenge: Sodium L-lactate solution was infused intravenously. Sodium L-lactate (0.18 ± 0.02 moles) was dissolved in 20 mL sterile phosphate buffered saline (PBS), mixed thoroughly, and subsequently placed into an IV infusion bag with accompanying pump for administration a rate of 1500 mL/h over a 15-min infusion time. Intravenous Glucose Challenge: 36 g, 18.0 mL bolus of 50% dextrose solution was given IV to the animal over 3 min. Respiratory Challenge: Physiological lactic acidosis secondary to hypoxia and hypercapnia was induced by decreasing minute ventilation [44]. Hypercapnia/hypoxia was induced by first drawing blood from the animal and then infusing the blood back to the animal while decreasing 70–75% minute ventilation from baseline.…”

“…Respiratory Challenge: Physiological lactic acidosis secondary to hypoxia and hypercapnia was induced by decreasing minute ventilation [44]. Hypercapnia/hypoxia was induced by first drawing blood from the animal and then infusing the blood back to the animal while decreasing 70–75% minute ventilation from baseline.…”

Extracorporeal Support for Chronic Obstructive Pulmonary Disease: A Bright Future

“…65,66 Others have attempted AVCO 2 R using axillary or subclavian vessels in animal models (Figure 3). 67,68 These upper body access sites do not limit mobility and present promising options for future AV systems. Thus for a long-term system, grafting end to side onto upper body vessels would be the ideal method of access.…”

A Membrane Lung Design Based on Circular Blood Flow Paths

“…1B). The specifications for the initial lung design were intended for testing in our model of end stage lung disease (ESLD) 9 driven by arterial blood pressure without a pump. 10 These specifications are: fiber length 2 cm, device diameter 10 cm, rated flow ≥1 L/min, oxygen transfer at rated flow ≥50 mL/min, pressure drop at 1L/min of 60 mmHg, and CO 2 clearance that is four times oxygen transfer.…”