Comparison of Weight-based Versus External Ear-size Based Technique for Selection of Laryngeal Mask Airway in Pediatric Surgical Patients.

Laryngeal Mask Airway (LMA) is widely used in pediatric surgical patients. The manufacturer recommends the size of LMA to be used in children should be based on actual body weight but this method has several limitations. To overcome these concerns, various alternatives have been tried by different researchers, one of them is external ear size for LMA size selection. Investigators therefore would like to know whether the external ear size based method can be used for LMA size selection in pediatric surgical patients in Pakistan.

OBJECTIVE:

to determine whether external ear-size is non-inferior to weight for LMA size selection in pediatric surgical patients.

INTRODUCTION:

The Laryngeal Mask Airway (LMA) is widely used in pediatric population. The manufacturer recommends the size of LMA to be used in children should be based on actual body weight. However, this method has several limitations, the range of weight for a particular size is very wide, it may not be appropriate for overweight or underweight children as it is based on actual body weight rather than ideal body weight, in emergency situations where weight of the patient is unknown the correlation between weight and size of LMA is impossible, and finally weight based recommendation may not be suitable as development of the child's oropharyngeal cavity is related to height and age rather than weight. All these factors may lead to inappropriate size selection, which may result in larger sized LMA causing trauma/injury to the airway and smaller ones causing obstruction or insufficient ventilation. To overcome these concerns various alternatives to weight based technique have been tried by different researchers in both adult and pediatric patients, one of them is external ear size. Literature revealed differences in external ear size dimensions in different ethnic population and the investigator's literature search failed to reveal any local data/study in Pakistani pediatric patients where external ear size was compared or used for size selection of the LMA. The investigators therefore would like to know whether the external ear size based method can be used for LMA size selection in pediatric surgical patients in Pakistan.

HYPOTHESIS:

External ear-size based technique is not inferior to weight based technique for LMA selection in pediatric population.

Eligibility Criteria:
Inclusion Criteria:

1. All children aged between 6 months to 18 years of age of either sex
2. American Society of Anesthesiologist (ASA) Classification I-II
3. Elective surgical procedures in whom an LMA will be indicated
4. Procedure lasting up to 2hrs

Exclusion Criteria:

1. Any external ear morphological abnormality
2. Previous external ear surgeries
3. Patient/Parent refusal
4. Children with oropharyngeal lesion
5. Any patient conditions (Gastroesophageal Re-flux Disease \[GERD\], hiatal hernia, incomplete NPO, bowel obstruction etc.) or procedures requiring rapid sequence induction and intubation
6. History of Upper respiratory tract infection (URTI) within the last 2 weeks