Methemoglobinemia with the use of benzocaine spray for awake fiberoptic intubation.

We report a case in which the use of benzocaine spray to facilitate awake fiber optic intubation (FOI) in a patient with a difficult airway caused methemoglobinemia intraoperatively. Local benzocaine was sprayed to numb the patient's airway for a total time of one second, fifteen minutes later SpO2 decreased to 85% on the pulse oximeter. Arterial blood gas (ABG) showed a MetHb of 24.6% of total Hemoglobin. The patient was successfully treated with methylene blue intravenously and recovered uneventfully. Small amounts of local benzocaine sprayed to numb the airway can cause significant methemoglobinemia that requires immediate recognition and appropriate management.

Temporally Coordinated Deep Brain Stimulation in the Dorsal and Ventral Striatum Synergistically Enhances Associative Learning.

The primate brain has the remarkable ability of mapping sensory stimuli into motor behaviors that can lead to positive outcomes. We have previously shown that during the reinforcement of visual-motor behavior, activity in the caudate nucleus is correlated with the rate of learning. Moreover, phasic microstimulation in the caudate during the reinforcement period was shown to enhance associative learning, demonstrating the importance of temporal specificity to manipulate learning related changes. Here we present evidence that extends upon our previous finding by demonstrating that temporally coordinated phasic deep brain stimulation across both the nucleus accumbens and caudate can further enhance associative learning. Monkeys performed a visual-motor associative learning task and received stimulation at time points critical to learning related changes. Resulting performance revealed an enhancement in the rate, ceiling, and reaction times of learning. Stimulation of each brain region alone or at different time points did not generate the same effect.