Table 2.

Effect of bolus volume and external cricoid pressures on hypopharyngeal intrabolus pressure

External Cricoid Pressure	DS	5 ml	10 ml
0 mmHg	3.3 ± 0.8	6.8 ± 0.9†	8.7 ± 0.9†
20 mmHg	4.8 ± 0.7	8.6 ± 1.0*†	10.6 ± 1.0*†
30 mmHg	5.1 ± 0.8*	10.1 ± 1.0*†	12.2 ± 1.2*†
40 mmHg	7.0 ± 1.2*	11.2 ± 1.1*†	13.0 ± 1.1*†

Values are mean mmHg ± SE.

^*P < 0.05 compared with no external cricoid pressure at each tested bolus volume;

^†P < 0.05 compared with DS at each tested external cricoid pressure.