Immediate responses of arterial blood pressure and heart rate to sudden inhalation of high concentrations of isoflurane in normotensive and hypertensive patients.

Inhalation of pungent volatile anesthetics elicits respiratory reflex responses. To clarify whether an upper airway irritation produced by pungent anesthetics can also induce circulatory reflex responses that are clinically significant, a sudden administration of 5% isoflurane by mask was performed during continuous measurement of arterial blood pressure (BP) and heart rate (HR) in eight normotensive and eight hypertensive patients anesthetized with thiamylal and paralyzed with vecuronium. The sudden administration of 5% isoflurane caused immediate increases in BP, HR, and rate pressure products (RPP) in both normotensive and hypertensive patients. The responses observed were more pronounced in hypertensive than in normotensive patients. The circulatory changes in hypertensive patients were sufficient to be clinically significant. Our findings suggest that sudden administration of a high concentration of pungent volatile anesthetics may be associated with transient hypertensive responses in hypertensive patients with coronary artery disease.