A comparison of McGrath MAC, Pentax AWS, and Macintosh direct laryngoscopes for nasotracheal intubation: a randomized controlled trial

Figures & data

Table 1 Modified nasal intubation–difficulty scale (MNIDS).¹²

Parameter	Score
N1: Intubation attempts	Each additional intubation attempts after the first one adds 1 point
N2: Operators to attempt intubation	Each additional operator required to attempt intubation adds 1 point
N3: Alternative intubation techniques or change head position	Each alternative technique or change of head position adds 1 point
N4: glottis exposure	0 = good visualization of vocal cords with little manipulation
	1 = tools manipulated in all directions to identify the vocal cords
	2 = tools extensively manipulated in all directions to identify the vocal cords
N5: Lifting force required to expose the vocal cords	0 = lifting without assistance 1 = lifting required by assistant to improve view of the vocal cords
N6: Optimize glottis exposure with BURP	0 = none 1 = BURP applied
N7: Techniques to aid intubation	0 = none 1 = cuff inflation or use of Magill forceps

Notes: Reproduced from: Lee MC, Tseng KY, Shen YC, et al.Nasotracheal intubation in patients with limited mouth opening: a comparison between fibreoptic intubation and the Trachway(R). Anaesthesia. 2016;71(1):31–38, with permission from John Wiley and Sons.¹²

Abbreviation: BURP, backward–upward–rightward pressure.

Table 2 Ease of second step using sequence of additional maneuvers.⁵

Grade	Maneuvers
M0	Intubation without maneuvers
M1	Use of external manipulations, such as tube rotation, head flexion, BURP maneuver
M2	Use of ETT cuff inflation alone
M3	Use of ETT cuff inflation with external manipulation (M1 + M2)
M4	Use of Magill forceps alone
M5	Use of Magill forceps with external manipulation (M1 + M4)

Note: Reproduced from: Patil VV, Subramanya BH, Kiranchand N, Bhaskar SB, Dammur S. Does C-MAC((R)) video laryngoscope improve the nasotracheal intubating conditions compared to macintosh direct laryngoscope in paediatric patients posted for tonsillectomy surgeries? 2016;60(10):732–736. http://www.ijaweb.org/.⁵

Abbreviations: BURP, backward–upward–rightward pressure; ETT, endotracheal tube.

Figure 1 CONSORT flow diagram.

Table 3 Patient characteristics

Parameters	Macintosh (n=41)	McGrath (n=41)	Pentax (n=41)
Male sex, n (%)	23 (56.1)	30 (73.2)	22 (53.7)
Age, years	34.6±13.9	35.9±14.0	38.9±15.3
Weight, kg	63.2±13.0	67.3±14.6	64.7±12.5
Height, cm	167.5±8.8	168.9±9.2	167.6±10.2
ASA, n (%)
I/II	37 (90.2)/4 (9.8)	37 (90.2)/4 (9.8)	35 (85.4)/6 (14.6)
Tube size, ID (mm)
6.0/6.5	18 (43.9)/23 (56.1)	12 (29.3)/29 (70.7)	19 (46.3)/22 (53.7)
Nostril, n (%)
Left/right	3 (7.3)/38 (92.7)	5 (12.2)/36 (87.8)	2 (4.9)/39 (95.1)

Note: Values are means ± SD or n (%).

Abbreviations: ASA, American Society of Anesthesiologists (physical status); ID, internal diameter.

Table 4 Intubation profiles

Parameters	Macintosh (n=41)	McGrath (n=41)	Pentax (n=41)	p-value
Cormack–Lehane grade, n (%)				0
I	15 (36.6)	34 (82.9)	26 (63.4)
IIa	15 (36.6)	4 (9.8)	12 (29.3)
IIb	8 (19.5)	3 (7.3)	2 (4.9)
III	3 (7.3)	0 (0)	1 (2.4)
Success rate, n (%)	41 (100)	41 (100)	41 (100)	1
Difficulty	0.5 (0–1)	0 (0–1)	0 (0–1)	0.741
MNIDS
Total	0 (0–0)	0 (0–0)	0 (0–0)	0.283
N1 0/1/2, n (%)	39/2/0 (95.1/4.9/0)	39/2/0 (95.1/4.9/0)	38/2/1 (92.7/4.9/2.4)	1
N2 0/1, n (%)	41/0 (100/0)	41/0 (100/0)	41/0 (100/0)	—
N3 0/1, n (%)	40/1 (97.6/2.4)	41/0 (100/0)	40/1 (97.6/2.4)	1
N4 0/1/2, n (%)	36/5/0 (87.8/12.2/0)	39/2/0 (95.1/4.9/0)	37/4/0 (90.2/9.8/0)	0.621
N5 0/1, n (%)	36/5 (87.8/12.2)	39/2 (95.1/4.9)	37/4 (90.2/9.8)	0.621
N6 0/1, n (%)	33/8 (80.5/19.5)	38/3 (92.7/7.3)	39/2 (95.1/4.9)	0.140
N7 0/1, n (%)	38/3 (92.7/7.3)	40/1 (97.6/2.4)	41/0 (100/0)	0.322
Epistaxis
1/2/3/4, n (%)	29/12/0/0 (70.7/29.3/0/0)	30/11/0/0 (73.2/26.8/0/0)	30/11/0/0 (73.2/26.8/0/0)	1

Notes: Values are means ± SD, median (IQR), or n (%). Difficulty and subjective difficulty represented by numeric rating scale (1 = extremely easy, 10 = extremely difficult).

Abbreviation: MNIDS, modified nasotracheal intubation–difficulty score.

Table 5 Intubation profile according by step

Parameters	Macintosh (n=41)	McGrath (n=41)	Pentax (n=41)	p-value
Total intubation time, seconds	34.6±8.1	35.2±7.9	36.2±9.7	0.727
First step
Time, seconds	6.5±3.9	6.8±3.4	5.3±4.1	0.185
Easiness
1/2/3, n (%)	27/10/4 (65.9/24.4/9.8)	23/12/6 (56.1/29.3/14.6)	34/3/3 (85.0/7.5/7.5)	0.059
Second step
Time, seconds	11.8±6.3	10.3±3.5	15.1±7.6	0.001
Ease, n (%)				0.099
M0	30 (73.2)	36 (87.8)	29 (70.7)
M1	8 (19.5)	4 (9.8)	12 (29.3)
M2	2 (4.9	1 (2.4)	0
M3	0	0	0
M4	0	0	0
M5	1 (2.4)	0	0
Third step
Time, seconds	2.9±2.6	4.4±5.6	1.7±0.7	0.001
Ease
1/2/3, n (%)	31/10/0 (75.6/24.4/0)	28/13/0 (68.3/31.7/0)	37/4/0 (90.2/9.8/0)	0.058

Notes: Values are means ± SD, median (IQR), or n (%). First step, nose to oropharynx; second step, oropharynx to laryngeal inlet; third step, laryngeal inlet to trachea. The ease of the second step was evaluated according to Table 2.

Table 6 Maneuvers

Maneuver	Macintosh (n=41)	McGrath (n=41)	Pentax (n=41)	p-value
BURP	8 (19.5)	4 (9.8)	3 (7.3)	0.303
Magill forceps	1 (2.4)	0	0	0.221
Head flexion	0	0	1 (2.4)	0.221
Cuff inflation	2 (4.9)	1 (0.8)	0	0.064
Tube rotation	18 (43.9)	19 (46.3)	15 (36.6)	0.720

Note: Values are n (%).

Abbreviation: BURP, backward–upward–rightward pressure.

Lee MC, Tseng KY, Shen YC, et al. Nasotracheal intubation in patients with limited mouth opening: a comparison between fibreoptic intubation and the Trachway(R). Anaesthesia. 2016;71(1):31–38. doi:10.1111/anae.1323226460721

 PubMed Web of Science ®Google Scholar

Patil VV, Subramanya BH, Kiranchand N, Bhaskar SB, Dammur S. Does C-MAC((R)) video laryngoscope improve the nasotracheal intubating conditions compared to macintosh direct laryngoscope in paediatric patients posted for tonsillectomy surgeries? Indian J Anaesth. 2016;60(10):732–736. doi:10.4103/0019-5049.19167627761036

 PubMedGoogle Scholar