Pediatric Airway Assessment. a Retrospective Computerized Axial Tomography Study to Determine the Optimal Localization to Secure an Emergent Pediatric Airway

Title:  Pediatric airway assessment.  A retrospective computerized axial tomography study to determine the optimal localization to secure an emergent pediatric airway.

Introduction:  Catheterization of the trachea is an option to temporarily secure an emergent pediatric airway.

Methods: The concept of a Òsafe zoneÓ limited superiorly by the attachment of the vocal cords [upper limit] and inferiorly by the inferior aspect of the thyroid isthmus [lower limit] was used as a theoretical area for midline catheterization of the airway in an emergent pediatric airway.  This area was selected as it is largely devoid of significant neural and vascular structures.  External landmarks of the mental-tracheal corner and the superior aspect of the manubrium were selected to determine if a relationship could be determined.

Results: The sample consisted of 66 head and neck CT scans of children (age range: 1 to 12 years).  Roentgen Works software was used for data interpretation and management.  A board certified radiologist participated in this study.

The most consistent findings were noted in the relationship of the mental tracheal-corner with the anterior attachment of the vocal folds:

Age Group	N	Minimum (mm)*	Maximum (mm)
1-3	20	-5.63	12.71
4-6	13	-9.35	6.84
7-9	14	-7.37	13.37
10-12	19	-10.18	21.81

*A negative number indicating the anterior attachment of the vocal folds being superior to the mental tracheal-corner.

Vertebral levels were used as landmarks for measurement in consideration of tissue thickness [TT] AP and tracheal distance [TD] AP.  These measurements transected the Òsafe zoneÓ.  TT showed much variability.  This could be attributed to the non-neutral head position noted in many of the head and neck CT scans.  TD showed much more uniform data which can be attributed to the cartilaginous framework of the trachea.

In the 1-3 age group (mean 2.15, sd 0.81) the following data was noted:

Vertebral Level	Tissue Thickness (mm)	Tracheal Distance (mm)
C4	Mean 7.96, sd 1.8	Mean 7.62, sd 0.75
C5	Mean 9.22, sd 2.59	Mean 7.78, sd 1.01
C6	Mean 11.84, sd 4.13	Mean 7.48, sd 0.87

In the 4-6 age group (mean 5.15, sd 0.69) the following data was noted:

Vertebral Level	Tissue Thickness (mm)	Tracheal Distance (mm)
C4	Mean 9.00, sd 1.66	Mean 9.88, sd 0.42
C5	Mean 13.78, sd 7.75	Mean 9.08, sd 1.62
C6	Mean 11.84, sd 4.13	Mean 7.48, sd 0.87

In the 7-9 age group (mean 8.00, sd 0.78) the following data was noted:

Vertebral Level	Tissue Thickness (mm)	Tracheal Distance (mm)
C5	Mean 13.69, sd 10.01	Mean 10.55, sd 1.23
C6	Mean 14.42, sd 9.59	Mean 9.49, sd 1.05
C7	Mean 9.59, sd 2.15	Mean 10.14, sd 0.63

In the 10-12 age group (mean 11.21, sd 0.85) the following data was noted:

Vertebral Level	Tissue Thickness (mm)	Tracheal Distance (mm)
C5	Mean 12.43, sd 7.13	Mean 12.13, sd 2.16
C6	Mean 12.25, sd 4.98	Mean 11.48, sd 1.75
C7	Mean 12.35, sd 6.21	Mean 12.44, sd 1.39

Conclusion: This preliminary data suggest that an index finger could be used at the mental tracheal corner as a landmark for catheterization. Vertebral levels were used as landmarks for measurement in consideration of tissue thickness [TT] AP and tracheal distance [TD] AP.  These measurements transected the Òsafe zoneÓ. This study reveals that the mental tracheal corner can be used as a reliable reference point when considering emergent catheterization of the trachea in a pediatric patient.  

References:

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2.    Sadda R, Turner M. Emergency tracheotomy in the dental office. Int J Oral Maxillofac Surg. 2009.