Table 1. Changes of vital signs in three groups before and after tracheal intubation.

		MAP		HR		SpO2
		(mmHg)	P value	(beats.min-1)	P value	(%)	P value
Group I (20-49 years old patients)	Baseline	95.6 (11.7)	78.5 (12.0)			97.6 (1.5)
	After fentanyl and tramadol administration
	1 min	101.5 (13.2)	<0.001*	81.3 (11.4)	0.054	96.8 (2.2)	0.217
	3 min	97.6 (12.6)	0.426	82.1 (12.4)	0.001*	96.2 (2.3)	0.030*
	5 min	97.5 (11.5)	0.423	80.7 (12.4)	0.100	96.5 (2.3)	0.068
	After thyrocricoid puncture
	1 min	100.3 (13.2)	0.060	85.0 (14.2)	0.013*	97.2 (1.5)	0.240
	3 min	97.73 (11.2)	0.254	82.1 (12.6)	0.047*	97.4 (1.8)	0.585
	5 min	99.0 (11.9)	0.055	82.7 (12.2)	0.106	97.8 (1.4)	0.584
	After fibreoptic nasal tracheal intubation
	1 min	98.5 (13.0)	0.308	81.5 (11.8)	0.176	97.8 (1.4)	0.697
	3 min	97.6 (13.5)	0.505	81.0 (11.1)	0.271	98.2 (1.7)	0.264
	5 min	96.1 (11.9)	0.875	81.1 (9.2)	0.333	98.4 (1.6)	0.094
Group II (50-69 years old patients)	Baseline	94.0 (13.9)		74.8 (17.6)		97.2 (0.9)
	After fentanyl and tramadol administration
	1 min	98.0 (11.9)	0.062	75.7 (19.8)	0.450	97.3 (1.2)	0.166
	3 min	99.0 (11.1)	0.064	77.0 (17.2)	0.177	95.6 (1.9)	0.004*
	5 min	99.5 (13.7)	0.002*	77.7 (16.3)	0.164	96.3 (1.6)	0.085
	After thyrocricoid puncture
	1 min	100.5 (11.6)	0.024*	84.0 (19.6)	0.040*	95.2 (1.6)	<0.001*
	3 min	97.0 (10.5)	0.172	78.6 (15.3)	0.110	96.6 (0.8)	0.007
	5 min	97.2 (8.9)	0.323	78.3 (16.5)	0.130	97.3 (1.4)	0.615
	After fibreoptic nasal tracheal intubation
	1 min	99.2 (12.1)	0.031*	80.5 (17.6)	0.012*	96.5 (0.5)	0.039*
	3 min	97.0 (11.3)	0.367	78.3 (17.1)	0.087	97.5 (0.5)	0.266
	5 min	93.8 (7.8)	0.970	77.0 (16.6)	0.158	97.8 (0.9)	0.220
Group III (more than 70 years old patients)	Baseline	113.3 (10.8)		83.2 (8.7)		96.3 (1.3)
	After fentanyl and tramadol administration
	1 min	114.5 (8.4)	0.250	83.4 (10.4)	0.785	96.3 (0.9)	0.980
	3 min	116.1 (2.9)	0.260	81.6 (8.8)	0.045*	96.3 (1.3)	1.000
	5 min	112.2 (5.2)	0.763	81.2 (12.3)	0.173	96.4 (1.96)	0.892
	After thyrocricoid puncture
	1 min	117.2 (4.2)	0.114	82.8 (9.3)	0.670	96.5 (1.7)	0.772
	3 min	114.5 (3.1)	0.624	83.2 (9.6)	0.889	97.2 (1.6)	0.218
	5 min	112.5 (5.2)	0.770	82.0 (10.0)	0.037*	97.8 (1.3)	0.014*
	After fibreoptic nasal tracheal intubation
	1 min	116.8 (6.2)	0.205	81.8 (9.3)	0.268	97.3 (1.4)	0.179
	3 min	113.0 (7.2)	0.823	81.2 (9.8)	0.032*	98.0 (1.3)	0.030*
	5 min	111.0 (6.1)	0.271	81.6 (9.6)	0.045*	98.5 (1.0)	0.001*

MAP, mean arterial blood pressure; HR, heart rate;baseline, immediately before fentanyl and tramadol administration. *,compared with baseline, P<0.05.