Brain temperature in volunteers subjected to intranasal cooling

• Published in: Intensive care medicine Vol. 37; no. 8; pp. 1277 - 1284
• Main Authors: Covaciu, L., Weis, J., Bengtsson, C., Allers, M., Lunderquist, A., Ahlström, H., Rubertsson, S.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.08.2011; Springer; Springer Nature B.V
• Subjects: Administration, Intranasal; Adult; Anaesthetics and intensive care; Anestesi och intensivvård; Anestesiologi och intensivvård; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Anesthesiology; Anesthesiology and Intensive Care; Biological and medical sciences; Blood pressure; Body mass index; Body temperature; Body Temperature - physiology; Brain; Brain - physiology; Brain research; Brain temperature; Catheterization - instrumentation; Catheterization - methods; Catheters; Clinical Medicine; Cognitive ability; Cooling; Critical Care Medicine; Emergency Medicine; Female; Fysiologi och farmakologi; Health aspects; Heart beat; Heart rate; Humans; Hypothermia; Hypothermia, Induced - instrumentation; Hypothermia, Induced - methods; Injuries of the nervous system and the skull. Diseases due to physical agents; Intensive; Intensive care; Intensive care medicine; Inventories; Kirurgi; Klinisk medicin; Magnetic resonance; Magnetic Resonance Spectroscopy - methods; Male; Medical and Health Sciences; Medical sciences; MEDICIN; Medicin och hälsovetenskap; MEDICINE; Medicine & Public Health; Methods; Middle Aged; Monitoring, Physiologic - methods; N.M.R; Neuroimaging; Nose; Original; Pain Medicine; Pediatrics; Physiological aspects; Physiology and pharmacology; Pneumology/Respiratory System; Radiologi; Radiological research; Radiologisk forskning; Radiology; Secretion; Selective brain cooling; Sodium Chloride - administration & dosage; Spatial distribution; spectroscopy; Surgery; Temperature effects; Therapeutic hypothermia; Thermography - methods; Thoracic surgery; Traumas. Diseases due to physical agents; Trigeminal reflex; Volunteers; Young Adult; Sweden; United States > US; Finland; Magnetic resonance spectroscopy; Selective brain cooling; Trigeminal reflex; Therapeutic hypothermia; Brain temperature; Human; Intensive care; Cooling; Central nervous system; Therapeutic; NMR spectrometry; Encephalon; Treatment; Resuscitation; Hypothermia
• ISSN: 0342-4642; 1432-1238; 1432-1238
• DOI: 10.1007/s00134-011-2264-7

Purpose Intranasal cooling can be used to initiate therapeutic hypothermia. However, direct measurement of brain temperature is difficult and the intra-cerebral distribution of temperature changes with cooling is unknown. The purpose of this study was to measure the brain temperature of human volunteers subjected to intranasal cooling using non-invasive magnetic resonance (MR) methods. Methods Intranasal balloons catheters circulated with saline at 20°C were applied for 60 min in ten awake volunteers. No sedation was used. Brain temperature changes were measured and mapped using MR spectroscopic imaging (MRSI) and phase-mapping techniques. Heart rate and blood pressure were monitored throughout the experiment. Rectal temperature was measured before and after the cooling. Mini Mental State Examination (MMSE) test and nasal inspection were done before and after the cooling. Questionnaires about the subjects’ personal experience were completed after the experiment. Results Brain temperature decrease measured by MRSI was −1.7 ± 0.8°C and by phase-mapping −1.8 ± 0.9°C ( n  = 9) at the end of cooling. Spatial distribution of temperature changes was relatively uniform. Rectal temperature decreased by −0.5 ± 0.3°C ( n  = 5). The physiological parameters were stable and no shivering was reported. The volunteers remained alert during cooling and no cognitive dysfunctions were apparent in the MMSE test. Postcooling nasal examination detected increased nasal secretion in nine of the ten volunteers. Volunteers’ acceptance of the method was good. Conclusion Both MR techniques revealed brain temperature reductions after 60 min of intranasal cooling with balloons circulated with saline at 20°C in awake, unsedated volunteers.