Figure 39-6 Relationship between the rate of muscle response to stimulation of the tracheal carina and the degree of neuromuscular blockade of peripheral muscles, as evaluated by using post-tetanic count. The subjects were 25 patients anesthetized with thiopental, nitrous oxide, and fentanyl who were given vecuronium (0.1 mg/kg) for tracheal intubation. For comparison, the first response to TOF stimulation usually occurs when PTC is approximately 10 (range, 6 to 16). The carina was stimulated with a soft sterile rubber suction catheter introduced via the endotracheal tube. The total response consisted of mild responses plus severe response. A mild response was said to occur if stimulation of the carina induced only slight bucking that did not interfere with surgery. A severe response was said to occur if stimulation elicited bucking that interfered with surgery and required intervention. Elimination of severe responses requires an intense neuromuscular blockade; PTC must be less than 2 to 3, and elimination of all reactions requires that PTC be 0. (From Fernando PUE, Viby-Mogensen J, Bonsu AK, et al: Relationship between post-tetanic count and response to carinal stimulation during vecuronium-induced neuromuscular blockade. Acta Anaesthesiol Scand 31:593, 1987. Copyright 1987, Munksgaard International Publishers, Ltd. Copenhagen, Denmark.)