AUTHOR INSTRUCTIONS: (Anesthesia & Analgesia)

Title Page and structured Abstract of no more than 400 words.

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TTILE PAGE: Comparative efficacy of McGrath Mac video laryngoscope Vs McIntosh laryngoscope in patients undergoing maxillo-facial surgeries for panfacial fractures, A randomized controlled trial

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RUNNING TITILE: efficacy of McGrath Mac video laryngoscope Vs McIntosh laryngoscope among patients with panfacial projects

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BLINDED MANUSCRIPT:

INTRODUCTIONEndotracheal intubation is considered as the gold standard of airway

management.1 Delay or difficulty during laryngoscopy and intubation may

increase patient morbidity and mortality apart from causing significant

desaturation, dental or airway injuries.1 Direct laryngoscopy envisioned by

McIntosh and Miller has been accepted as a standard of care for more than 60

years.2

Airway Management during maxillofacial surgeries poses an unique challenge

to the anesthetist because of various factors that include but are not limited to

decreased mouth opening, sharing of airway with the surgeon, need for

assessment of occlusion and inability of routine airway assessment parameters

to adequately assess airway pre-operatively.3 Patients with facial fractures

undergoing oral and maxillofacial surgery often have decreased mouth opening

due to spasm of muscles and oedema at the fracture site. Hence routine

endotracheal intubation using conventional direct laryngoscopy may not be ideal

in these patients.

Unless contra-indicated maxillofacial surgeries are performed using

nasotracheal intubation.4 These patients commonly require nasotracheal

intubation during open reduction and internal fixation of fractures to facilitate oral

access to surgery and are known to pose the problem of difficult airway to

anesthetists.5

Video laryngoscopes have been a new addition to the anesthetists’

armamentarium to secure the airway in anesthetized patients.6-9 The basic

advantage that a video laryngoscope offers is that the oral, pharyngeal and

laryngeal axes need not align with the line of vision to achieve glottic visualization

for the purpose of endotracheal intubation.10-14 Thus we can say that they offer a

look around the corner. Though video laryngoscopes provide excellent glottic

views, this does not consistently translate into easier intubations, as difficulty is

often encountered in passing of the endotracheal tube into the larynx owing to

non-alignment of the three axeses.14

One such video laryngoscope is the McGrath Mac video laryngoscope.13 The

design of McGrath video laryngoscope resembles that of a Macintosh

laryngoscope, with the addition of a complementary metal oxide semiconductor

(CMOS) chip camera in place of the light bulb of Macintosh blade and a camera

screen connected to the handle of the scope.6, 7 It offers the familiarity of a direct

laryngoscope with the advantage of video laryngoscope being that there is a

paradigm shift in view of larynx from the hypo pharynx.8

There are studies to evaluate the use of video laryngoscopes for routine

orotracheal intubations.15-19 Fewer studies are done on the role of video

laryngoscopy in nasotracheal intubations more so in patients with facial

fractures20-27 This study is an effort to evaluate if this innovation of video

laryngoscopy actually translates into faster and easier laryngoscopy and

nasotracheal intubation in patients with pan facial fractures undergoing oral and

maxillofacial surgeries under general anesthesia. There are very few studies to

know utility of McGrath Mac video laryngoscope for nasotracheal intubation in

contrast to direct laryngoscopy using McIntosh laryngoscope.29 Hence this study

is indicated.

Hypothesis:

The nasotracheal intubation using McGrath Mac video laryngoscope provides a

better intubating conditions as compared to conventional direct laryngoscopy in

patients undergoing maxilla-facial surgeries for panfacial fractures under general

anesthesia.

Objectives:

To compare the efficacy of nasotracheal intubation using McGrath Mac video

laryngoscope versus McIntosh laryngoscope in patients undergoing maxilla-

facial surgeries for panfacial fractures under general anesthesia.

To compare hemodynamic response to laryngoscopy and intubation in both

the groups.

METHODOLOGYIn this prospective, open label, quasi randomized controlled study, adult

patients in the age group of 18-65 yrs and ASA status I and II undergoing elective

oral and maxillofacial surgeries with pan facial fractures under general anesthesia at

Sri Siddhartha Medical College Hospital and Research center, Agalakote, Tumkur,

from November 2016 to November 2017 were included in the study.

The study has excluded people aged less than 18 years or more than 65 years,

MPG Grade III and IV, ASA Grade III, IV and V, Patients with mouth opening <

2cms, Patients with h/o trauma to cervical spine.Patients with oropharyngeal mass,

Patients with untreated head injury Pregnant patients, Patients with nasal bone

fractures and Patients with skull base fracture

The study population was divided into 2 groups with 20 patients in each group.

Group I : McGrath group (n =20)

Group II : McIntosh Group (n =20)

Randomization was done using computer generated random number sequence,

using IBM SPSS statistical software version 21.28 Allocation concealment was done

by sequentially numbered, opaque sealed envelopes (SNOSE) method as

advocated by Doig, G. S. et al.29 Investigator blinding was not possible, considering

the nature of intervention. The study participants were blinded for the intervention by

opening the device after induction of anaesthesia. The statistician analyzing the data

was also blinded for the intervention.

The sample size was calculated based on the mean and standard deviation obtained

in the percentage of glottis opening score in both the devices from previous study

done by Taylor et al. using the formula. The power set at 80% and 5% probability of

type 1 error. The absolute value obtained was 39, which was rounded off to 40, i.e.,

20 in each group.

The study was approved by institutional human Ethics committee. The study was

registered with clinical trials.org (registration number: ). Informed written consent

was obtained from all the study participants, after explaining the risks and benefits

involved in the study, voluntary nature of participation. The confidentiality of the data

was maintained throughout the study period and while reporting of the results.

Standard operating protocol for general anesthesia (common to both the groups)

included pre anesthesia evaluation and pre anesthetic management was done as

per the standard hospital protocol. Pre- induction hemodynamic parameters were

recorded- namely- heart rate, SBP, DBP and MAP.Nasal mucosa was prepared by

instilling 2 drops of xylometazoline 0.5% nasal drops in both the nostrils 20 minutes

before the induction. Pre- medication given was Inj. Glycopyrrolate 10μg/kg

bodyweight and Inj. Ondansetron 0.1mg/kg intravenously 10 min before

induction.Pre- oxygenation was done using bag and mask ventilation using 100%

oxygen at 8L/min by closed circuit with the patient breathing spontaneously for 3

minutes.Intra- venous induction was done using Inj. Propofol 2mg/kg body weight

and muscle relaxation was obtained by using Inj. Scoline 2mg/kg body weight. Inj.

Nalbuphine 0.4mg/kg was used in both the groups.2% lignocaine jelly was applied to

the right nostril. Post induction hemodynamic parameters were recorded. Bag and

mask ventilation was done for 1 minute.. Endotracheal tubes no. 7.5 will be used in

male participants and no.6.5 will be used for female participants.

i) Depending on the group assigned either Mcgrath videolaryngoscope or

McIntosh laryngoscope will be used for intubation. Blade no. 4 was used

for all male patients and no. 3 was used for all female patients.

ii) After insertion of the tube through right nares into the naso pharynx,

laryngoscopy was performed using the pre- assigned device. Time taken

for laryngoscopy was defined from the time the laryngoscope is taken to

the left hand to the time when best possible view without any OELM was

obtained. The observer then recorded the POGO score and C & L grading.

iii) After laryngoscopy, the time taken for intubation, which was defined as the

time from obtaining best possible view with or without OELM to the point

of obtaining a single reliable EtCO2 on the monitor was recorded.

iv) Post laryngoscopy hemodynamic parameters were recorded.

v) Use of OELM and Magill’s forceps were recorded. After intubation, tube

was secured

vi) Anesthesia is maintained with 50% nitrous oxide, 1% Isoflurane in

Oxygen. Inj.Vecuronium 0.1mg/kg of loading dose followed by intermittent

bolus of 0.02mg/kg will be used in both groups for maintanence.

vii) Hemodynamic parameters were recorded subsequently for 20 minutes

post laryngoscopy every 5 min.

viii) After completion of surgery, patient is reversed with Inj. Neostigmine

0.05mg/kg and Inj. Glycopyrrolate. 0.01mg/kg Oral cavity is inspected

using laryngoscope for bleeding and patient is extubated after suctioning.

All steps are same in both the groups except for the use of Mcgrath

videolaryngoscope in the first group and McIntosh laryngoscope in the second

group.

To ensure that there is no bias of experienced and novice anesthetists all

intubations are performed by a single anesthetist routinely using both the

devices.

Intubating anesthetist will have no knowledge of which group each participant

will be allotted to as the sealed opaque envelope will be opened only after

patient is shifted to the operation theater by the observer- a senior anesthetist

in the department.

Time taken for intubation will be measured by a stop-watch by the observer.

Time taken for laryngoscopy was defined as the time from taking the

laryngoscope to the hand to the time best possible laryngeal view is obtained

before application of OELM. Time taken for intubation is defined as the time

elapsed from the time obtaining the best possible view (after OELM – if

required) to the appearance of a definite EtCO2 tracing on the monitor.

POGO score and Cormack and Lehanne grading is also decided by the

observer. In case of Mcgrath VL seen by directly observing the screen,

whereas in the Mcintosh group by direct observation by leaning over after

laryngoscopy.

Proforma for data collection is filled and the data tabulated.

key outcome measures assessed in the study were the Laryngoscopic view, time

taken for intubation, use of optimization maneuvers and hemodynamic response.

The data was entered into Microsoft excel was analyzed using IBM SPSS statistical

software version 21. The data was checked for checked for any unusual values and

missing values were modified accordingly. The data was analyzed using Intention to

treat (ITT) analysis. The quantitative variables were checked for normal distribution

within each group using shapiro- wilk’s test (p>0.5) 30, 31 and a visual inspection of

their histograms, normal Q-Q plots and box plots showed that the exam scores were

approximately normally distributed for both males and females, with a skewness of

0.374 (SE = 0.365) and a kurtosis of -0.881 (SE 0.717) for the males and a

skewness of -0.012 (SE = 0.388) and a kurtosis of -0.881 (SE=0.759) for the

females.32-34

Descriptive and inferential statistical analysis was carried out in the present study.

Results on continuous measurements are presented on Mean SD (Min-Max) and

results on categorical measurements are presented in Number (%). Significance is

assessed at 5 % level of significance. The quantitative variables were compared

between the two groups using independent sample-test and the categorical variables

were compared using Chi square test/ Fisher’s exact test.P value < 0.05 was

considered statistically significant.

RESULTS:

A total of 40 subjects were included in the final analysis, with 20 subjects in each

group. The mean age of group I was 35.70±13.29 and group II was 34.30±12.05,

with no statistically significant difference between the groups (P value 0.729). In both

the study groups, the proportion of males was very high (90% in group I and 80% in

group II), but the difference between the two groups was statistically significant (P

value 0.661). Both the study groups were comparable with respect to other baseline

variables including anthropometric parameters, ASA grade, MPG grade, Thyro

mental Distance and HE. (Table 1)

Higher proportion of the subjects in group I had glottis Opening > 4 cm as compared

to group II (50% VS 25%), but the differences in proportion of subjects with different

degrees of mouth opening was statistically not significant between two groups (P

value 0. 253). The mean percentage of glottic opening in of group I was higher than

group II (98.25±2.94 Vs 42.25±14.91, P value < 0.001). In group I, all 20(100%)

people had Cormack and Leanne grade 1. In group II, 16(80%) people had Cormack

and Leanne grade 2, and 4(20%) people had Cormack and Leanne grade 3. The

mean time taken for laryngoscopy of group I was significantly shorter compared to

group II (10.50±1.88 Vs 15.65±2.52, Value < 0.001) The mean time taken for

intubation of group I was shorter, compared to group II (14.10±3.26 Vs 21.95±4.72,

P value < 0.001). The mean total time taken for intubation of group I was significantly

shorter as compared to group II (24.60±4.11 Vs 37.45±6.12, P value <0.001). (Table

2)

In group I and II all of them 20 (100%) had intubation done in first pass. In group I,

10(50%) had optimal external laryngeal manipulation. In group II, 19(95%) had

optimal external laryngeal manipulation. The difference in the proportion of optimal

external laryngeal manipulation between study group was statistically significant (P

value 0.001). None of the subjects in group 1 required Magill’s use, whereas 95% of

the subjects in group II required Magill’s use. (Table 3)

No statistical difference was found in the mean heart rate between the two study

groups at different follow-up periods. No statistical difference was found in the mean

systolic blood pressure between the two study groups at different follow-up periods.

No statistical difference was found in the mean diastolic blood pressure between the

two study groups at different follow-up periods. (Figure 1 to 3)

DISCUSSION:

Glottic exposure parameters:In the present study glottic view was assessed using percentage of glottis opening

(POGO) score and Cormack and Lehanne grading. The POGO score in group 1 was

98.25±2.94 (%) (Mean± SD) and group 2 was 42.25±14.91 (%) (Mean± SD). This

shows that glottic view was significantly better in group 1 (p<0.001). Similar results of

POGO score during the use of Truview EVO2 laryngoscope was noted in a study

done by Shreshta et al. 24 They noted POGO score was 93.00 ±15.9 (mean± SD)

and 62.50 ± 32.1 (mean± SD) in Truview and McIntosh group respectively (p<0.001).

C& L grade 1 view was obtained in all the 20 cases in Mcgrath group. In McIntosh

group grade 2 views was obtained in 16 cases and grade 3 views in 4 cases. The

difference was again highly significant (p< 0.001). Similar high incidence of grade 1

view with McGrath VL was noted by Kwak et al27 (Grade1/2(%)MVL-83/17, DL-57/43

p=.019). Lower incidence of Grade 1 view in McIntosh group could be attributed to

decreased mouth opening owing to fractures involving facial bones and associated

edema and spasm.

Time taken for intubation-With the intention of analyzing the precise step of difference between the two

devices, Time taken for intubation was divided into 2 divisions, time taken for

laryngoscopy and time taken for intubation as defined in the methodology section.

Time taken for laryngoscopy was 10.50±1.88 s in McGrath group and 15.65±2.52 s

in McIntosh Group, and the difference was statistically significant (p<0.001). In a

study conducted by Tseng et al 25 McIntosh group had longer time of laryngoscopy

nevertheless no statistically significant difference was noted (GVL-14.1 ± 5.0, PAS-

17.0 ± 7.4, DL- 19.6 ± 15.8 p=0.095)

In the present study, mean time taken for intubation was significantly shorter with

McGrath VL (14.10±3.26s) compared to McIntosh group (21.95±4.72s p<0.001).

Tseng et al 25in their study noted shorter time to intubation with Glidescope

videolaryngoscope, and pentax airway scope when compared to McIntosh

laryngoscope (GVL-9.9 ± 5.2s PAS- 12.9 ± 10.8s, McIntosh 15.3 ± 8.5s, p= 0.028-

significant)

The total time taken for intubation was 24.60±4.11s (mean± SD) in McGrath group

and 37.45±6.12s (mean± SD) in McIntosh group, the difference was statistically

highly significant similar to the results obtained by Kwak et al27. In the study

conducted by Kwak et al27 time take to nasotracheal intubation was significantly

lower with McGrath VL (MVL-39.6 ±15.5(s), DL-44.9 ± 15.6(s)(mean± SD)

p=.004)when compared to McIntosh laryngoscope.

First pass intubation- all the 40 patients were intubated in the first attempt in both the

groups.

Optimisation maneuvers-

Two optimization manouvers namely use of optimal external laryngeal manipulation

and use of Magill’s forceps were recorded during the study.

Optimal external laryngeal manipulation was required in 10 (50%) cases in McGrath

group and 19(95%) cases in McIntosh group. This difference was statistically highly

significant (p<0.001). Puchner et al 22in their comparision of Glidescope VL , Airtraq

VL with McIntosh laryngoscope did not find a statistically significant difference

between the devices in terms of use of OELM(AOL-10% ,GVL- 15%, DL- 20% no

significant difference). Were as in a study conducted by Tseng et al Glidescope

video laryngoscope and Pentax airway scope were associated with significantly

lesser incidence of use of OELM (GVL-2.8, PAS-0, DL-15 (%)p<0.001)

The second optimization maneuver studied was use of Magill’s forceps. In this study

all 20 (100%) patients in McGrath group were intubated without using Magill’s

forceps in contrast to McIntosh group where 1(5%) patient was intubated without

using the forceps, and 19 (95%) patients required it’s use to achieve intubation. The

difference between the 2 groups was again statistically highly significant (p<0.001).

Jones et al in their prospective randomized study on nasotracheal intubation using

Glidescope VL and McIntosh laryngoscopes, noted that GVL required significantly

lesser usage of Magill’s forceps (0%vs 49% p<0.001). Kwak et al27in their

prospective RCT noted the similar finding of lesser use of Magill’s forceps in their

study comparing McGrath VL with DL (MVL-17, DL-97 (%)p=.004)

Hemodynamic parametersThe hemodynamic parameters studied included heart rate, systolic blood pressure,

diastolic blood pressure and mean arterial pressure. Pre induction values were

compared and no statistically significant difference was found in the pre induction

values in both the groups. Post induction HR, SBP, DBP and MAP were comparable

between 2 groups and no statistically significant difference was noted.

Post laryngoscope increase in HR was noted in both the groups. The difference was

not statistically significant. No meaningful inferences could be drawn from

hemodynamic parameters recorded in both the groups and none were statistically

significant. Logically, there should have been a significantly lesser hemodynamic

response to McGrath given the findings of significantly easier intubations. In our

opinion the sample size might be too small to show the difference. Noninvasive

blood pressure monitoring may not be reliable in such a small sample and a very

short duration of events

The results obtained in our study show that McGrath VL is associated with

significantly better

glottis views both in terms of POGO score and C&L grading, shorter time to

laryngoscopy, intubation and also total time taken for intubation, lesser use of

optimization maneuvers like OELM and use of Magill’s forceps and lower intubation

difficulty score.

Limitations of the studyBlinding was not possible as both the intubating anesthetist and the observer would

be aware of the instrument used in that particular patient. The results may or may

not be universal; it may not hold good for all the video laryngoscopes, for all patients

and all operators too. Any study on video laryngoscopes is like hitting a moving

target, newer devices and innovations are seen so frequently that a study that it is

difficult accommodate all the possible new ones. The skill of laryngoscopy and

intubation is mastered only with practice. Hence a novice anesthetist may find

intubation with either of the devices more difficult than experienced anesthetist. In

the present study, a single anesthetist well trained in use of both devices performed

all of the intubations; hence the factor of the experience of anesthetist that plays a

vital role was not studied. Likewise, not all patients are similar. Hence this study may

or may not hold well in all of the patients for example pediatric population.

The study did not show any significant difference in the hemodynamic stress

response in spite of a huge difference in ease of intubation. This may be attributed to

the small sample size which was calculated using the glottis exposure parameters

alone. A larger sample size may be needed to demonstrate subtle differences in

these parameters

Hence it can be concluded that, McGrath video laryngoscope facilitates nasotracheal

intubations in patients with pan facial fractures posted for oral and maxillofacial

surgeries in terms of Glottis exposure parameters, shorter time taken for intubation –

both time taken for laryngoscopy and intubation were significantly shorter with

McGrath video laryngoscope. Use of optimization maneuvers namely use of OELM

and Magill’s forceps were significantly lesser with McGrath video laryngoscope. The

need to use a Magill’s forceps did not arise in any of the 20 patients in the McGrath

group. However, there was no statistically significant difference in the hemodynamic

response to laryngoscopy and nasotracheal intubation in both the group

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34. Doane DP, Seward LE. Measuring skewness: a forgotten statistic? Journal of

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CONSORT 2010 Flow Diagram

Assessed for eligibility (n= 56)

Excluded (n=16)  Not meeting inclusion criteria (n= 14)  Declined to participate (n=2)  Other reasons (n= 0)

Analysed (n= 20 ) Excluded from analysis (give reasons) (n= 0)

Lost to follow-up (give reasons) (n= 0)

Allocated to group I(McGrath) (n= 20) Received allocated intervention (n=20) Did not receive allocated intervention (give

reasons) (n= 0 )

Allocated to group II (McIntosh) (n= 20) Received allocated intervention (n= 20) Did not receive allocated intervention (give

reasons) (n= 0)

Analysed (n= 20) Excluded from analysis (give reasons) (n= 0)

Allocation

Analysis

Follow-Up

Randomized (n= 40)

Enrollment

Lost to follow-up (give reasons) (n= 0)

Table 1: Comparison of baseline parameters between the two study groups

Base line parameters Group I (N=20) Group II (N=20) P value

Age in years (Mean ±

SD)35.70±13.29 34.30±12.05 0.729

GenderFemale 2(10%) 4(20%)

0.661Male 18(90%) 16(80%)

Height (cm) 167.55±8.28 164.60±8.79 0.75

Weight (kg) 68.85±10.97 67.05±9.69 0.22

BMI (kg/m2) 24.56±3.91 23.13±3.40 0.225

ASA GradeGrade I 8(40%) 12(60%)

0.206Grade II 12(60%) 8(40%)

MPG

Grade 1 2(10%) 1(5%)

NDGrade 2 16(80%) 15(75%)

Grade 3 2(10%) 4(20%)

Grade 4 0(0%) 0(0%)

TMD>6.5 cm 18(90%) 19(95%)

1.000≤6.5cm 2(10%) 1(5%)

HE

1 20(100%) 20(100%) ND

2 0(0%) 0(0%)

ND: Not done

Table 2: Comparison of efficacy of intubation between the two study groups

Parameter Group I (N=20) Group II (N=20) P value

Mouth Opening

>4cm 10(50%) 5(25%)

0.2533-4 cm 8(40%) 12(60%)

Up to 3 cm 2(10%) 3(15%)

Percentage of Glottic opening (Mean ± SD)

98.25±2.94 42.25±14.91 <0.001

Cormack and Leanne grading

Grade1 20(100%) 0(0%)

**Grade 2 0(0%) 16(80%)

Grade 3 0(0%) 4(20%)

Parameter

Time taken for

laryngoscopy

(Mean ± SD)

10.50±1.88 15.65±2.52 <0.001

Time Taken for

intubation (Mean ± SD)14.10±3.26 21.95±4.72 <0.001

Total Time taken for

intubation in seconds

(Mean ± SD)

24.60±4.11 37.45±6.12 <0.001

**No statistical test was applied- due to 0 subjects in the cells.

Table 3: Comparison of other intubation efficacy related parameters between two study groups

Parameter Group I (N=20) Group II (N=20) P value

Intubation done in first pass

Yes 20(100%) 20(100%)**

No 0(0%) 0(0%)

Optimal external laryngeal manipulationYes 10(50%) 19(95%)

0.001No 10(50%) 1(5%)

Magill’s use

Yes 0(0%) 19(95%)**

No 20(100%) 1(5%)

*No statistical test was applied- due to 0 subjects in the cells.

Figure 1: Comparison of heart rate variation in both the groups

·Prei

nduc

tion

·Post

indu

ction

·Post

laryn

gosco

py·5

min

·10 m

in

·15 m

in

·20min

·30 m

in0

10

20

30

40

50

60

70

80

90

100

Group I

Group II

Hea

rt r

ate

(bpm

)

Figure 2: Comparison of variation of systolic blood pressure

·Prei

nduc

tion

·Post

indu

ction

·Post

laryn

gosco

py·5

min

·10 m

in

·15 m

in

·20min

·30 m

in100

105

110

115

120

125

130

135

140Group I

Group II

SBP(

mm

Hg)

Figure 3: Comparison of variation of systolic blood pressure

·Prei

nduc

tion

·Post

indu

ction

·Post

laryn

gosco

py·5

min

·10 m

in

·15 m

in

·20min

·30 m

in0

10

20

30

40

50

60

70

80

90

100

Group I

Group II

DBP

(mm

Hg)