Treatment of resistant fever: new method of local cerebral cooling.

BACKGROUND: Fever in neurocritical care patients is common and has a negative impact on neurological outcome. The purpose of this prospective observational study was (1) to evaluate the practicability of cooling with newly developed neck pads in the daily setting of neurointensive care unit (NICU) patients and (2) to evaluate its effectiveness as a surrogate endpoint to indicate the feasibility of neck cooling as a new method for intractable fever. METHODS: Nine patients with ten episodes of intractable fever and aneurysmal subarachnoid hemorrhage were treated with one of two different shapes of specifically adapted cooling neck pads. Temperature values of the brain, blood, and urinary bladder were taken close meshed after application of the cooling neck pads up to hour 8. RESULTS: The brain, blood, and urinary bladder temperatures decreased significantly from hour 0 to a minimum in hour 5 (P < 0.01). After hour 5, instead of continuous cooling in all the patients, the temperature of all the three sites remounted. CONCLUSION: This study showed the practicability of local cooling for intractable fever using the newly developed neck pads in the daily setting of NICU patients.

Theoretical evaluations of therapeutic systemic and local cerebral hypothermia.

PURPOSE: To simulate cerebral temperature behaviour with hypothermia treatment applying different cooling devices and to find the optimal brain temperature monitoring. METHODS: Models based on hourly temperature values recorded in patients with severe aneurysmal subarachnoid hemorrhage, taking MRI data, thermal conductive properties, metabolism and blood flow into account were applied to different scenarios of hypothermia. RESULTS: Systemic hypothermia by endovascular cooling leads to an uniform temperature decrease within the brain tissue. Cooling with head caps lead to 33 degrees C only in the superficial brain while the deep brain remains higher than 36 degrees C. Cooling with neckbands lead to 35.8 degrees C for dry and 32.8 degrees C for wet skin in the deep brain. CONCLUSIONS: With head caps temperatures below 36 degrees C cannot be reached in the deep brain tissue, whereas neckbands, covering the carotid triangles, may lead to hypothermic temperatures in the deep brain tissue. Temperature sensors have to be applied at least 2 cm below the cortical surface to give values representative for deep brain tissue.

Self-correction mechanism for path integration in a modular navigation system on the basis of an egocentric spatial map.

Classical Computer Science approaches to navigation by autonomous robots continue to make good progress. However, we have only a limited understanding of how navigation is implemented in the neural networks of animals, which still perform very much better in navigational tasks than robots. In this paper we explore the implementation of neural network based navigation in a simple robot. We use a modular navigation system that contains separate representations of visual input and the path integration process. These representations are combined to influence the behavior of a robot. Both representations are encoded within recurrent neuronal networks. The outputs of the representations are vectors of polar values that encode the location of the nearest object, or of a specific place in the environment. The robot manoeuvres in relation to these attended locations, in the context of its egocentric spatial map. During ego-motion towards a goal, the network representation of the goal moves in a counter-movement due to applied motor feedback. The robot's position is continuously compared against its visual input, and mismatches between the visually perceived goal position and its spatial representation are corrected.