Usefulness of video-laryngoscopy with the Airway Scope for intubation performance and learning: an experimental manikin controlled study

Annals of Intensive Care

Table 2 Factors potentially influencing endotracheal intubation time

	All attempts (n = 1200)		Univariable analysis*				Multivariable analysis**
	All attempts (n = 1200)		ETI Time (s)	95 % CI limits		p value	ETI time at first attempt for novices 1 (s)	Time multiplier***	95 % CI limits		p value
	Number of attempts, n	Sample arithmetic mean time (s)	ETI Time (s)	Lower	Upper	p value	ETI time at first attempt for novices 1 (s)	Time multiplier***	Lower	Upper	p value
ETI device	1200	19.63
DLM	600	24.52	20.44	16.18	25.83	<0.0001	35.65	–	29.61	42.93	<0.0001
AWS	600	14.73	12.72	10.08	16.06		22.51	–	18.75	27.02
Operator sub-group (device order)
Experts (DLM then AWS)	400	12.53	11.01	9.28	13.07	<0.0001	–	0.54	0.49	0.58	<0.0001
Novices 1 (DLM then AWS)	400	25.35	20.51	17.29	24.32		–	1.00	–	–	–
Novices 2 (AWS then DLM)	400	21.00	18.37	15.49	21.79	0.02	–	0.83	0.77	0.90	<0.0001
Attempt number in the series of 10 attempts
1	120	24.92	20.99	16.42	26.84	Reference	–	1.00	–	–	–
2	120	23.63	19.44	15.16	24.92	0.16	–	0.91	0.83	1.01	0.08
3	120	20.62	17.09	13.33	21.93	0.003	–	0.80	0.71	0.89	0.0001
4	120	19.56	15.92	12.41	20.42	<0.0001	–	0.74	0.66	0.84	<0.0001
5	120	18.76	15.22	11.87	19.51	<0.0001	–	0.71	0.63	0.80	<0.0001
6	120	18.22	14.87	11.59	19.09	<0.0001	–	0.69	0.62	0.77	<0.0001
7	120	18.65	15.34	11.94	19.72	<0.0001	–	0.71	0.63	0.80	<0.0001
8	120	17.81	14.59	11.35	18.75	<0.0001	–	0.68	0.60	0.76	<0.0001
9	120	17.03	14.06	10.96	18.03	<0.0001	–	0.65	0.58	0.73	<0.0001
10	120	17.06	13.69	10.61	17.66	<0.0001	–	0.63	0.57	0.70	<0.0001

ETI endotracheal intubation, DLM direct laryngoscopy with Macintosh, AWS video-laryngoscopy with Airway Scope®
* Univariable analysis, all the 1200 attempts have been analyzed separately according to 3 variables: ETI device (DLM vs. AWS), operator sub-group (experts vs. novices 1 and novices 1 vs. novices 2) and the attempt number in the series of 10 attempts
** Novices 1 at the first attempt serve as reference situation of the multivariable analysis, i.e., the simultaneous analysis of 3 variables: ETI device (DLM vs. AWS), operator sub-group (experts vs. novices 1 and novices 1 vs. novices 2) and the attempt number in the series of 10 attempts
*** Multiplicative factor allowing to estimate ETI time from the novices 1 ETI time for the others situations. For example, ETI time for an expert using AWS at first attempt is estimated to be 12.16 s, i.e., 22.51 × 0.54 × 1