A comparison table between the various studies showing the width/depth ratio of the trachea is shown in the table below (Table - 15).
TABLE – 15
CHART 5 : SHOWING COMPARISON BETWEEN VARIOUS STUDIES OF WIDTH/DEPTH RATIO OF THE TRACHEA.
1.14
R Chuner et al(2010) Present study(2016)
Width/Depth ratio of Trachea
Width/Depth ratio of Trachea
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The normal Width/Depth ratio of the major airways is below 1.5 and this increases in patients with chronic obstructive pulmonary disease (COPD) and saber-sheath trachea. Diffuse narrowing of the trachea or main bronchi secondary to various causes results in decreasing values. In the present study, the width/depth ratio of the trachea is calculated and it has been observed that the mean value is 1.2 and 1.1 in male and female specimens respectively which was significant statistically (p value <0.05) and is within the normal range and is comparable with the R Chunder et al49.
Left Main stem Bronchus(LMB) - Length(Cm)
The length of the left main bronchus in the present study is compared with the other studies and is shown in the table below (Table - 16).
TABLE – 16
6. Present study 3.6-5.5.& Mean/SD=5.0±0.5 3.5-4.0.& Mean/SD=4.0±0.2
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CHART 6 : SHOWING COMPARISON BETWEEN VARIOUS STUDIES OF LEFT MAIN BRONCHUS LENGTH.
From the above table the mean length of left main stem bronchus in various studies is almost similar except in Mrudula C45 (2011) the value is slightly on the lower limit. The length of left principal bronchus was 3.6-5.5 with a mean of 5.0 and 3.5-4.0 with a mean of 4.0 cm in male and female specimens respectively and was highly significant statistically (p value <0.001).This morphometric parameter is absolutely essential for clinicians for choosing appropriate double lumen endotracheal tube and airway stents
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Left Main stem Bronchus(LMB) – Width
The external transverse diameter (width) of the left principal bronchus in the present study is compared with the other studies and is shown in the table below (Table - 17).
TABLE – 17
S.No NAME OF AUTHOR (YEAR)
LEFT MAIN BRONCHUS -WIDTH(cm)
1 Standring et al, (2008)
1.1-1.9 (Male) 0.9-1.5 (Female)
2 R Chunder et al (2010)
1.5 (Male) 1.5 (Female)
3 Mrudula C (2011) 1.5
4 Present study
1.2-2.0.& Mean/SD=1.6±0.3 1.0-1.6.& Mean/SD=1.3±0.2
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CHART 7 : SHOWING COMPARISON BETWEEN VARIOUS STUDIES OF LEFT MAIN BRONCHUS - WIDTH
It has been observed from the table above, the external transverse diameter or the width of the left main stem bronchus of various studies ranges from 1.5 to 1.9 cm and in the present study it is 1.2-2.0 with a mean of 1.6 cm in male and 1.0-1.6 and a mean of 1.3 cm among female which was significant statistically (p value <0.05) and is almost similar with other studies.
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Left Main stem Bronchus(LMB) – Depth
The comparison table between other studies of left main stem bronchus is
2 Present study 1.1-1.8.& Mean/SD=1.4±0.2 1.0-1.5.& Mean/SD=1.2±0.2
CHART 8 : SHOWING COMPARISON BETWEEN VARIOUS STUDIES OF LEFT MAIN BRONCHUS - DEPTH.
1.24
R Chunder et al(2010) Present study(2016)
LMB Depth(cm)
LMB Depth(cm)
68
It has been observed from the table above, the antero posterior diameter or the depth of the left main stem bronchus from R Chunder et al49 (2010) ranges from 1.5-1.7,1.0-1.4 cm in male and female and in the present study it is 1.1-1.8 with a mean of 1.4 cm in male and 1.0-1.5 and a mean of 1.2 cm among female which was significant statistically (p value <0.05) and is almost close to the above study. This aspect should be borne in mind during interventional procedures.
Left Main stem Bronchus(LMB) - Width/Depth ratio
A comparison table between the other studies showing the width/depth ratio of the left main stem bronchus is shown in the table below (Table - 19).
TABLE – 19
S.
No
NAME OF AUTHOR (YEAR)
LEFT MAIN BRONCHUS – WIDTH/DEPTH RATIO
1 R Chunder et al (2010) 1.15-1.36 (Male) 1.18-1.47 (Female)
2 Present study 1.0-1.3.& Mean/SD=1.1±0.1 1.0-1.2.& Mean/SD=1.1±0.1
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CHART 9 : SHOWING COMPARISON BETWEEN VARIOUS STUDIES OF WIDTH/DEPTH RATIO OF LEFT MAIN BRONCHUS
The Width/Depth ratio of the larger airways is below 1.5 normally and this ratio increases in patients with COPD and saber-sheath bronchus. Diffuse narrowing of the left main stem bronchus or its counterpart secondary to various causes results in decreasing values. In the present study, the width/depth ratio of the left main stem bronchus is calculated and it has been observed that the mean value is 1.1 for both male and female specimens respectively which was not statistically significant (p value <0.431) and the ratio is significantly lower to the previous study. The diameters of the main bronchi should be known precisely for the selection of proper tubes for different gender.
1.24
R Chunder et al(2010) Present study(2016)
LMB - Width/Depth ratio
Width/Depth ratio
70
Subcarinal Angle
The comparison table between various studies of subcarinal angle is tabulated below(Table - 20).
TABLE – 20
S.No NAME OF AUTHOR
(YEAR) SUBCARINAL ANGLE (DEGREES) 1 Latarjet.M (1956) 40-108
2 Boyd E (1958) 43.5 to 46
3 CoppoleV ( 1998) 37-105
4 R Chunder et al (2010) 56.4-59.5(Male) 48.2-54.0(Female) 5 Mrudula C (2011) 50-130
6 Mani S.Kavuru (2012) 70-75
7 Present study 51-63.& Mean/SD=56.1±4.6 47-63.& Mean/SD=52.1±4.6
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CHART 10 : SHOWING COMPARISON BETWEEN VARIOUS STUDIES OF SUBCARINAL ANGLE
Regarding the subcarinal angle there is wide variation among the studies listed above. The minimum angle of 37 degrees was observed by CoppoleV10 ( 1998) and a maximum of 130 degrees in Mrudula C45 (2011) which may be related to the dynamicity of this structure. Variations as large as 26 degrees can occur during respiratory maneuvers and several pathologic conditions can also cause widening of this angle. In the present study no wide variations were observed and the angle for male ranges from 51-63 degrees with a mean of 56 degrees and for the female it ranges from 47-63 degrees with a mean of 52 degrees, and was statistically significant (p value <0.05), and is comparable with the R Chunder et a49l. The knowledge regarding the subcarinal angle is of clinical importance for bronchoscopic procedures and any growth in the mediastinal
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72
structures or any pathology of the lung or pleura or cardiac diseases may alter the subcarinal angle considerably
Left Main stem Bronchus(LMB) – ANGLE
The left main bronchus angle in the present study is compared with the various studies and is shown in the table below (Table - 21).
TABLE – 21
S.No NAME OF AUTHOR (YEAR)
LEFT MAIN BRONCHUS - ANGLE (DEGREES)
1 Boyd E (1958) 43.5 – 46
2 Miller (1997) 40
3 Richard S Snell (2003) 50
4 Mrudula C (2011) 30-60
5 Present study 32-48.& Mean/SD=40.0±4.9 33-49.& Mean/SD=41.0±5.0
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CHART 11 : SHOWING COMPARISON BETWEEN VARIOUS STUDIES OF LEFT MAIN BRONCHUS ANGLE
Regarding the left main bronchi angle there is wide variation among the studies listed above. The minimum angle of 30 degrees and a maximum of 60 degrees was observed by in Mrudula C45 (2011) which may be related to the undiagnosed pathological conditions. In the present study the angle for male ranges from 32-48 degrees with a mean of 45 degrees and for the female it ranges from 33-49 degrees with a mean of 41 degrees, and was not statistically significant (p value <0.249). The left main bronchus contributes the major part of the subcarinal angle3 and the contribution by right bronchus is small as the later is almost in line with the trachea1. This considerably longer, narrower, more horizontal course and its peribronchial52 area in the left lung is under pressure makes it more prone to obstruction and this likely to affect the drainage of secretions leading to left bronchus syndrome39.
0
Boyd E (1958) Miller (1997) Richard S Snell (2003)