Introduction: Therapeutic hypothermia is a powerful and controversial clinical tool, with a complex developmental history as a mode of neuroprotection. Although promising from the cellular and CNS perspective, systemic side effects have limited clinical utility, confounding focused analysis of the true potential for neurologic benefits, and inhibiting useful clinical trials. Correspondingly, a robust, targeted model for inducing intracranial hypothermia while minimizing adverse systemic effects would have significant implications across a range of neurologic injury-states. NeuroSave is a novel, noninvasive, critical care medical device that employs continuous circulation of cold saline through the oropharyngeal cavity to deliver focal cerebrovascular cooling.
Methods: e conducted a preclinical safety and efficacy trial in an adult porcine model, to assess the validity and functionality of the NeuroSave device. Two animals were anesthetized, intubated with both an endotracheal tube and an esophageal balloon cuff, and then connected to the Neurosave cold-saline circulating system (Figure 1A, B). A frontal burr hole was drilled, and bicerebral intrahemispheric fiber optic temperature probes were implanted for continuous intraparenchymal temperature monitoring. The device was activated, the cooling cycle was initiated, and following prolonged monitoring, normothermia was restored (Figure 2). Chest and head CTs prior to, during, and following cooling; intracranial and core temperatures were recorded, and following animal sacrifice, post-mortem tissues were obtained for pathologic analysis.
Results: The NeuroSave device lowered brain parenchymal temperature by 9 degree C maximally, relative to core temperature, within 60 minutes of initiation. Neurologic cooling was stably maintained throughout the monitoring period, while the systemic body temperature, measured rectally, experienced a maximal reduction of 5%. Experimental animals were ventilated and supported without difficulty, and post-mortem analysis demonstrated no evidence of hypothermia-associated tissue injury in oropharyngeal mucosa or elsewhere.
Conclusions: The present study uses a large animal model to demonstrate the safety and efficacy of a novel, noninvasive device for the induction of robust, locally limited, systemically safe hypothermia. This device may therefore be used as targeted modality for neuroprotection of the brain parenchyma, without the incumbent risks of systemic hypothermia.
Patient Care: This pre-clinical trial evaluating a novel, non-invasive device targeting therapeutic hypothermia to the brain may have profound indications towards neuro critical care including post-ischemic states, traumatic injuries, diffuse axonal injury, or radiation-induced injury, as well as the potential for prophylactic protection during prolonged skull base or posterior fossa surgery.
Learning Objectives: 1) Highlight how focal therapeutic hypothermia may negate prior adverse effects of systemic therapuetic hypothermia
2) Discuss novel device development for neurologic critical care, and possibly intra-operative neurosurgery.
3) Identify an effective, non-invasive strategy for focused neurologic protection following various injuries or for prophylactic concerns.