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 Table of Contents  
Year : 2022  |  Volume : 9  |  Issue : 3  |  Page : 77-78

Estimating i-gel supraglottic airway size by thenar eminence dimensions versus weight-based method in the pediatric patient: Do they “gel” with each other?

1 Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States
2 Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia; Department of Anesthesiology, Critical Care and Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States

Date of Submission13-Apr-2022
Date of Acceptance20-Apr-2022
Date of Web Publication12-May-2022

Correspondence Address:
Dr. Vijay Srinivasan
Department of Anesthesiology and Critical Care Medicine, The Children's Hospital of Philadelphia, University of Pennsylvania Perelman School of Medicine, 3401 Civic Center Boulevard, Philadelphia 19104, Pennsylvania
United States
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jpcc.jpcc_32_22

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How to cite this article:
Senthil K, Srinivasan V. Estimating i-gel supraglottic airway size by thenar eminence dimensions versus weight-based method in the pediatric patient: Do they “gel” with each other?. J Pediatr Crit Care 2022;9:77-8

How to cite this URL:
Senthil K, Srinivasan V. Estimating i-gel supraglottic airway size by thenar eminence dimensions versus weight-based method in the pediatric patient: Do they “gel” with each other?. J Pediatr Crit Care [serial online] 2022 [cited 2023 Jun 8];9:77-8. Available from: http://www.jpcc.org.in/text.asp?2022/9/3/77/345094

Supraglottic airway (SGA) devices have a myriad of uses in children in a variety of settings, including routine intraoperative airway management, rescue from difficult bag mask ventilation, and expedient advanced airway placement during cardiac arrest.[1],[2] The availability of SGA devices has revolutionized anesthetic practice due to the first attempt success rate with SGAs exceeding 90% and associated diminished risk of oropharyngeal and airway trauma in comparison to the more traditional endotracheal intubations.[3] Unlike adult SGA devices, pediatric SGA devices vary widely in size due to developmental variations in the size of the pediatric airway. Pediatric SGA devices are typically sized by patient weight. While weight measurements are more readily available for patients undergoing elective surgery, in the out-of-hospital environment or during inhospital emergencies, patient weight may not be readily available, and sizing estimates tend to be unreliable.[4] In one prospective observational study comparing different methods of weight assessment in children, parental estimation of weight was the most accurate method (89% accuracy), while the Broselow length-based tape for weight estimation was the second-best method (55% accuracy).[5] Moreover, all estimates of weight in pediatric patients tend to be unreliable with considerable inaccuracy. A more reliable alternative method comparable or superior to weight-based measurement is therefore preferable in children.

In this issue of the Journal of Pediatric Critical Care, the authors report their findings of a randomized, single-blinded study to evaluate the ideal sizing of the i-gel SGA device in children aged 6 months to 12 years (5–30 kg) for routine surgeries, while excluding those with anticipated difficult airway, oropharyngeal lesions, or hand abnormalities.[6] A total of eighty subjects were recruited and randomized to forty subjects in each group (weight-based measurement group and thenar eminence dimension measurement group). The two groups were comparable for age, gender, weight, American Society of Anesthesiologists (ASA) status, and surgery type. The authors demonstrated superiority of i-gel sizing using thenar eminence dimension measurement method compared to weight-based measurement with regard to the primary outcome measure of leak fraction. Although the leak fraction was significantly lower in the thenar eminence dimension measurement group compared to the weight-based measurement group, the clinical significance of the absolute differences is unclear. In addition, insertion times, number of attempts, and optimal ventilation parameters were similar in both the groups. These findings endorse the potential utility of sizing the i-gel airway based on thenar eminence dimension measurements in out-of-hospital advanced airway management and during inhospital medical emergencies when patient weight may not be known and needs to be estimated.

The strengths of this study are that it is the first pediatric study to prospectively evaluate the efficacy of thenar eminence dimension measurements in comparison to the traditional weight-based method to obtain the size of i-gel SGA devices. In addition, the randomized study design successfully achieved balance across groups for demographic factors, ASA status, and surgical factors. The authors acquired pertinent clinical data points, such as insertion time, number of placement attempts, and leak fraction. An interesting observation that may affect the external validity of this study is the use of nondepolarizing neuromuscular blockade after SGA device placement. In institutions that do not commonly administer neuromuscular blockade during anesthetics with SGA devices, the presence of leak is mitigated considerably by spontaneous negative pressure ventilation. A limitation of the study is that the timing of SGA device insertion was calculated from the time of picking up the SGA device until the time to achieve adequate ventilation. This time period does not account for the process of performing a length and width measurement of the thenar eminence dimensions with a ruler, a process which would undoubtedly make the time to SGA device placement considerably slower in the thenar eminence dimension measurement group.

While this investigation has generated interesting findings, the ability to routinely implement SGA device sizing based on thenar eminence-based dimension measurements will require further work. Thenar eminence dimension measurements for this study were cumbersome to perform and are unlikely to be performed accurately and efficiently in a medical emergency. The practical operationalization of these findings in an out-of-hospital or inhospital setting will require a more streamlined and expedient process. Perhaps the simple placement of the device on the patient's palm and comparison to the thenar eminence dimensions to obtain the correct size may prove to be a valuable and efficient method during a medical emergency. As a practical consideration, a sizing guide or template placed on the patient's thenar eminence can help avoid the need to open multiple SGA devices and minimize wastage of equipment due to contamination.

Ultimately, the added value of this study is the potential to use thenar eminence dimension measurements to correctly assess the size of the i-gel SGA when weight-based measurements are unavailable or challenging to obtain. However, this begs the important question: in a prehospital or emergency setting, does an alternative approach to estimating SGA device size confer benefit? Is there harm in the current practice of estimating weight, placing an SGA device, evaluating ventilation adequacy, and resizing the device if necessary? Do these different methods “gel” with each other? These questions and more will need to be investigated further, but we can now begin to explore alternative and innovative nonweight-based approaches to address the problem of estimating the correct size of the i-gel SGA device in children in an emergency.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Duff JP, Topjian AA, Berg MD, Chan M, Haskell SE, Joyner BL Jr., et al. 2019 American Heart Association focused update on pediatric advanced life support: An update to the American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation 2019;140:e904-14.  Back to cited text no. 1
Patel B, Bingham R. Laryngeal mask airway and other supraglottic airway devices in paediatric practice. Contin Educ Anaesth Crit Care Pain 2009;9:6-9.  Back to cited text no. 2
Kleine-Brueggeney M, Gottfried A, Nabecker S, Greif R, Book M, Theiler L. Pediatric supraglottic airway devices in clinical practice: A prospective observational study. BMC Anesthesiol 2017;17:119.  Back to cited text no. 3
Lim CA, Kaufman BJ, O'Connor J Jr., Cunningham SJ. Accuracy of weight estimates in pediatric patients by prehospital Emergency Medical Services personnel. Am J Emerg Med 2013;31:1108-12.  Back to cited text no. 4
Samerchua A, Suraseranivongse S, Komoltri C. A comparison of pediatric weight estimation methods for emergency resuscitation. Pediatr Emerg Care 2019;35:705-11.  Back to cited text no. 5
Engineer SR, Sivashankari B, Sreekanth KT. A randomized trial to compare thenar eminence dimensions-based method with body weight method to determine I-gel size in pediatric patients. J Pediatr Crit Care 2022;9:95-9.  Back to cited text no. 6
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