Table 1.

Biomechanical measures (mean ± standard deviation [95% confidence intervals])

	Air (n = 7)	Saline (n = 8)	P-value
Plunger injection force applied (N)	13.9 ± 1.6 [12.5 to 15.3]	13.1 ± 5.4 [9.1 to 17.1]	0.73
Flow (mL.s−1)	13.2 ± 11.4 [3.2 to 23.2]	5.7 ± 2.3 [4.0 to 7.4]	0.09
Velocity (m.s−1)	6.5 ± 5.6 [2.4 to 10.6]	2.8 ± 1.1 [2.0 to 3.6]	0.09
Thrust (N)	0.17 ± 0.25 [0.00 to 0.39]	19.3 ±14.9 [8.3 to 30.3]	0.005
Dissipation time (ms)	290 ± 173 [138 to 442]	889 ± 655 [404 to 1374]	0.036
Needle tip stress (Pa)	7792 ± 920 [6986 to 8598]	7378 ± 3019 [5141 to 9615]	0.73