Fig. 5.
Schematic presentation of key factors for normal pharyngeal function and airway protection and the impact of age and partial neuromuscular block. Oral coordination (prevents penetration of contents to the laryngeal inlet or aspiration); coordination of the pharyngeal contraction wave (the propagation of contractions in the pharyngeal constrictor muscles into the upper esophageal sphincter [UES]); pharyngeal clearance (prevents retention of pharyngeal residue after completion of the pharyngeal contraction wave); UES (resting pressure in the UES contributes to airway protection by preventing aerophagia and regurgitation); laryngeal protection (prevents penetration of contents to the laryngeal inlet or aspiration); coordination of breathing and swallowing (swallowing during expiration and normal duration and timing of apnea in relation to the pharyngeal phase of swallowing prevents aspiration); *Sundman et al.21 ; **Bodén et al.22 ; †Hårdemark Cedborg et al.23 NMBA = neuromuscular-blocking agent.