Inducing brain cooling without core temperature reduction in pigs using a novel nasopharyngeal method: an efectiveness and safety study

Abstract

Background: Acute brain lesions constitute an alarming public health concern. Neuroprotective therapies have been implemented to stabilize, prevent, or reduce brain lesions, thus improving neurological outcomes and survival rates. Hypothermia is the most efective approach, mainly attributed to the reduction in cellular metabolic activity. Whole-body cooling is currently implemented by healthcare professionals; however, adverse events are frequent, lim‑iting the potential benefts of therapeutic hypothermia. Therefore, selective methods have been developed to reduce adverse events while delivering neuroprotection. Nasopharyngeal approaches are the safest and most efective meth‑ods currently considered. Our primary objective was to determine the efects of a novel nasopharyngeal catheter on the brain temperature of pigs. Methods: In this prospective, non randomized, interventional experimental trial, 10 crossbred pigs underwent naso‑pharyngeal cooling for 60 min followed by 15 min of rewarming. Nasopharyngeal catheters were inserted into the left nostril and properly positioned at the nasopharyngeal cavity. Results: Nasopharyngeal cooling was associated with a decrease in brain temperature, which was more signif‑cant in the left cerebral hemisphere (p=0.01). There was a reduction of 1.47±0.86 °C in the frst 5 min (p<0.001), 2.45±1.03 °C within 10 min (p<0.001), and 4.45±1.36 °C after 1 h (p<0.001). The brain-core gradient was 4.57±0.87 °C (p<0.001). Rectal, esophageal, and pulmonary artery temperatures and brain and systemic hemody‑namic parameters, remained stable during the procedure. Following brain cooling, values of oxygen partial pressure in brain tissue signifcantly decreased. No mucosal lesions were detected during nasal, pharyngeal, or oral inspection after nasopharyngeal catheter removal. Conclusions: In this study, a novel nasopharyngeal cooling catheter efectively induced and maintained exclusive brain cooling when combined with efective counter-warming methods. Exclusive brain cooling was safe with no device-related local or systemic complications and may be desired in selected patient populations.