To test the hypothesis that stimulation of cold receptors in the upper airway may alleviate the sensation of respiratory discomfort, we investigated the effects of nasal inhalation of l-menthol (a specific stimulant of cold receptors) on the respiratory sensation and ventilation during the loaded breathing in 11 normal subjects. Subjects were asked to rate their sensation of respiratory discomfort using a visual analog scale (VAS) while breathing on a device with a flow-resistive load (180 cm H2O/L/s) or with an elastic load (75.5 cm H2O/L). The effects of inhalation of l-menthol on ventilation and respiratory sensation were evaluated by comparing the steady-state values of ventilatory variables and VAS scores obtained before, during, and after l-menthol inhalation. In 8 of 11 subjects inhalation of strawberry-flavored air instead of l-menthol was performed during loaded breathing. Both during the flow-resistive loading and the elastic loading, inhalation of l-menthol caused a significant reduction in sensation of respiratory discomfort (flow-resistive loading: 62 +/- 14 [mean +/- SD] VAS units before inhalation versus 36 +/- 16 during inhalation, p < 0.01; elastic loading: 68 +/- 13 before inhalation versus 55 +/- 17 during inhalation, p < 0.01) without a significant change in breathing pattern and ventilation. Comparison of the effects between the flow-resistive loading and the elastic loading also revealed that the reduction in VAS score was more during the flow-resistive loading than during the elastic loading (p < 0.01). Inhalation of strawberry-flavored air caused neither changes in VAS score nor changes in breathing pattern and ventilation, indicating that olfaction is not a contributing factor in the relief of respiratory discomfort. We concluded that stimulation of cold receptors in the upper airway with nasal inhalation of l-menthol reduces the sensation of respiratory discomfort associated with loaded breathing. This effect is more effective during the flow-resistive loading than during the elastic loading.

The hypoxic ventilatory response is depressed by a high dose of halothane through a peripheral effect at the carotid body.

A woman with rheumatoid arthritis (RA) experienced glottic stenosis approximately two months after switching from etanercept to tocilizumab. Cricoarytenoid joint (CAJ) arthritis due to RA was diagnosed. An awake tracheostomy saved the relievable airway, and the administration of methylprednisolone and infliximab ameliorated the flare-up and glottic stenosis. A follow-up examination revealed the recovery of the patient's normal voice and good control of RA with infliximab and methotrexate. Although general physicians do not frequently encounter patients with symptomatic CAJ arthritis, this condition should be considered as it can be life-threatening. Therefore, when detected, it should be diagnosed and treated immediately.

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In anesthetized cats, we found that lung expansion reduces the tolerable limit to airway occlusion and vagotomy decreased minimum alveolar anesthetic concentration for airway occlusion, which suggests that pulmonary vagal afferents play an important role in relief of respiratory distress.