Local Brain Temperature Reduction Through Intranasal Cooling With the RhinoChill Device

Abstract

Background and Purpose-Hypothermia is neuroprotectant but currently available cooling methods are laborious, invasive, and require whole-body cooling. There is a need for less invasive cooling of the brain. This study was conducted to assess the safety and efficacy of temperature reduction of the RhinoChill transnasal cooling device. Methods-We conducted a prospective single-arm safety and feasibility study of intubated patients for whom temperature reduction was indicated. After rhinoscopy, the device was activated for 1 hour. Brain, tympanic, and core temperatures along with vital signs and laboratory studies were recorded. All general and device-related adverse events were collected for the entire hypothermia treatment. Results-A total of 15 patients (mean age, 50.3Ϯ17.1 years) were enrolled. Brain injury was caused by intracerebral hemorrhage, trauma, and ischemic stroke in equal numbers. Hypothermia was induced for fever control in 9 patients and for neuroprotection/intracranial pressure control in 6. Core temperature, brain temperature, and tympanic temperature were reduced an average of 1.1Ϯ0.6°C (range, 0.3 to 2.1°C), 1.4Ϯ0.4°C (range, 0.8 to 5.1°C), and 2.2Ϯ2°C (range, 0.5 to 6.5°C), respectively. Only 2 patients did not achieve the goal of Ն1°C decrease in temperature. Brain temperature , tympanic temperature , and core temperature reductions were similar between the afebrile and febrile patients. There were no unanticipated adverse events and only 1 anticipated adverse event: hypertension in 1 subject that led to discontinuation of cooling after 30 minutes. There were no nasal complications. Conclusions-Intranasal cooling with the RhinoChill device appears safe and effectively lowers brain and core temperatures. Further study is warranted to assess the efficacy of hypothermia through intranasal cooling for brain-injured patients. (Stroke. 2011;42:2164-2169.)

Induction of Cooling With a Passive Head and Neck Cooling Device

“…Although change of brain temperature was statistically significant, the achieved cooling rate is very low compared with alternative cooling methods already tested prehospitally. 8,17 Using intranasal cooling with the RhinoChill device, it was possible to reduce brain temperature by a mean of −0.53°C (SD, 0.24) in only 15 minutes, 17 which is significantly more than the decrease we found after 1 hour of surface head/neck cooling with the Sovika (mean, −0.32°C; SD, 0.2; P=0.012, please see Table and Small studies testing experimental active head cooling devices reported cooling rates of up to −0.6°C in deep (n=2 patients) and −1.84°C in superficial brain regions (−0.8 cm from cortex; n=8 patients). 9,10 Cold fluid circulating through these devices provides sustained heat exchange, but the need of an external liquid pump and electric power supply limits prehospital use.…”

“…8,17 Moreover, the transient increases of blood pressure and ICP warrant caution when using the Sovika head and neck cooling device. As tympanic and bladder temperature do not reflect the actual brain temperature and tend either to over-or underestimate cooling effects, our study emphasizes that brain temperature monitoring is mandatory for evaluation of (new) cooling methods.…”

“…17 Tympanic temperature approximates body core temperature under normothermic conditions and, for practical reasons, is preferred in the prehospital setting. 19 Consistent with the 2 recent trials, we found a large drop of in tympanic temperature starting immediately after external head cooling with the Sovika was applied reaching −1.69°C in mean after 1 hour of cooling.…”

Therapeutic temperature modulation is associated with pulmonary complications in patients with severe traumatic brain injury

“…Severe respiratory failure as a result of ARDS and/or pneumonia may adversely affect cerebral oxygenation and brain energy metabolism, and contribute to secondary brain injury. It is unknown if regional methods of cooling using new devices such as intranasal cooling [25,26] will offer the neurological benefits of TTM with fewer systemic side effects.…”

Letter by Albin Regarding Article, “Local Brain Temperature Reduction via Intranasal Cooling With the RhinoChill Device: Preliminary Safety Data in Brain-Injured Patients”

“…1 From a historical perspective, 47 years ago, Brown and colleagues produced a striking brain-body temperature gradient in canines by naso-oral perfusion and head immersion using cold saline as the hypothermic medium. 2 Within 20 to 38 minutes (median time, 32 minutes), intracerebral temperatures Ͻ20°C were reached with right atrial temperatures stabilizing between 30°C and 33°C.…”