Fig. 2.
(A and B) Morphine, (C and D) midazolam. (A and C) Degree of pharyngeal dysfunction at baseline recordings and after infusion of either morphine (0.1 mg/kg) (A) or midazolam (0.05 mg/kg) (C). After infusion was stopped, recordings were repeated at two occasions, that is, at 10 and 30 min, respectively. Severity of pharyngeal dysfunction increased significantly after subanesthetic doses of morphine or midazolam. *P < 0.05 versus baseline. (C and D) Frequency (%) of respiratory-phase pattern E-I, that is, the pattern inspiration-expiration-swallow apnea-inspiration recordings at baseline recordings and after infusion of either morphine (0.1 mg/kg) (C) or midazolam (0.05 mg/kg) (D). Coordination of breathing and swallowing was disrupted after midazolam (D), that is, there was an increased risk that swallowing would be followed by inspiration. *P < 0.05 versus baseline. Baseline = baseline recordings; C = control group; E-I = the respiratory-phase pattern with inspiration-expiration-swallow apnea-inspiration; Mi = midazolam; Mo = morphine; Mo10min/Mi10min, Mo30min/Mi30min = recordings 10 and 30 min after infusion of morphine/midazolam was stopped.