One of the major challenges in pediatric anesthesia is to maintain the patency of the airway during anesthesia, as, due to the particular anatomical and physiological characteristics of the pediatric population, there are differences between the pediatric and the adult airway,¹ and such differences represent a risk of severe, life-threatening respiratory complications.

While the nonventilation situation is considered rare in pediatrics, the nonintubation event is more frequent. Up to 4.7% of pediatric patients undergoing general anesthesia may present with difficult intubation.² Thus, it is desirable to have a device that facilitates blind intubation for salvage of the unexpected difficult airway. The Fastrach laryngeal mask (iLMA) is available for adult intubation and it is the standard of reference; however, the device is not available for children under 30 kg of body weight.

The single use I-Gel supraglottic device has shown a good performance for airway patency in children and adults.^3-6 It has a gastric aspiration canal, a bite blocker, and is a useful conduit for fiberoptic bronchoscopy.^7-9 In adults, it has been described as a blind endotracheal intubation device with a success rate of up to 80%.¹⁰ A prospective series of cases is discussed with the primary goal of establishing the percentage success rate for blind intubation in pediatrics. Secondary outcomes such as insertion times, seal pressure, fiber optics view, and adverse events are also evaluated.

A prospective case series of 39 patients admitted to the study upon approval by the ethics and research committees of the San Vicente Fundación University Hospital (HUSVF) and the Universidad de Antioquia. The patients included had a bodyweight ranging between 2 and 35 kg, ASA 1 and 2 status, and were scheduled for surgery and/or diagnostic procedures in the operating rooms of the pediatrics department of the HUSVF. Considering that the time to safe apnea could be too short for the tests with the device, patients ASA 3 and higher were excluded, as well as patients classified with a difficult airway; the recommended technique for these patients according to the pediatrics airway team is spontaneous ventilation intubation and flexible fiber optics. Patients not accepted by the treating anesthesiologist and/or for whom the procedure was not approved by their legal guardian were also excluded. The primary outcome was to establish the overall success rate of blind intubation on 3 attempts, using the I-Gel and based on the above-mentioned secondary outcomes.

The patients were recruited by 3 investigators who completed their learning curve of 20 procedures at the simulation laboratory, school of medicine, Universidad de Antioquia.

After giving an explanation to the patients' guardians, obtaining their approval and the approval of the treating anesthesiologist to participate in the study, every patient submitted his/her informed consent.

Fasting was confirmed, the medical record was reviewed, and the physical examination conducted; finally, the procedure was explained. No pre-medication was administered, and the induction of anesthesia was administered according to the anesthesiologist's criterion, ensuring adequate depth of anesthesia based on the absence of eyelid reflex, easy ascending and descending jaw movement, and absence of reaction when applying pressure on both mandibular commissures. Subsequently, a water-based lubricant was used and the I-Gel laryngeal mask was inserted in accordance with the manufacturer's instructions. Upon insertion of the laryngeal mask, the mask was then connected to the semi-closed circuit, fixing the mask to both jaws with micropore, and adequate performance was confirmed based on chest expansion, capnography, and absence of leaks.

The insertion time was measured from the removal of the facial mask to the occurrence of an adequate capnography wave. The mask was inserted by the anesthesiologist or the investigator, and then, the leak pressure was measured by closing the pressure relief valve and opening the flow of fresh gases to 3l/min. When an audible leak occurred, the pressure gauge measurement on the anesthesia machine was recorded. No pressure increases above 35 cmH20 were allowed.

Then, the fiberoptic view was evaluated and the scale by Cook and Cranshaw¹¹ was used, with a High, Ideal, or Low classification. Finally, 3 attempts of blind intubation were conducted, rotating the orotracheal tube in different directions: the first attempt was done with the tube curved against the I-Gel mask; the second attempt rotated the tube 90° clockwise with respect to the I-Gel curvature in case of resistance to passage of the tube in the first attempt. Finally, the last insertion attempt was done at 90° anti-clockwise. In case of successful intubation, the technique described for iLMA was used. In case of failed patient intubation, but if the patient required intubation at any rate, the mask was removed and direct laryngoscopy was performed. The variables and data were recorded, as well as any complications, until the patient was discharged from the post-anesthesia care unit.

The primary outcome was the percentage of successful blind intubations using the I-Gel mask, verifying with the first capnography and effective ventilation. The secondary outcomes were the percentage of successful blind intubations with the device, differentiating each attempt made, with the same primary outcome method. The proportion of fiberoptic view according to the scale by Cook and Cranshaw¹¹ was evaluated, seal pressure measurements were taken, and any adverse events were recorded.

Table 1 summarizes the demographic characteristics of the 39 patients recruited. Nine patients were intubated blindly, representing a global success rate of 23%; in 55% of the cases, intubation was successful at the first attempt, 22% at the second attempt, and 22% at the third attempt. Two patients (12.5%) were intubated with I-Gel, 3 patients (30%) were intubated with #1.5; no patients were intubated with #2, and finally 5 patients (50%) were intubated with #2.5. Considering the secondary end-points, the visualization of the glottic structures using the flexible fiberoptic bronchoscope, according to the classification by Cook and Cranshaw,¹¹ 35.8% of the cases were ideal, and a high view was achieved in 33.3% of the patients. The mean seal pressure measured in average 19.6cmH₂O (10-35cmH₂O). See Table 2.

Table 1

ASA=American Society of Anesthesia Classification of Physical Condition.

Table 2

cmH20=water centimetres.

Seven adverse events were reported (17.9%): bleeding at the time of device removal in 4 patients (10.2%), hypoxemia (pulse oximetry <92%) in 2 patients (5.1%), and 1 laryngospasm (2.56%) (Table 3).

Table 3

satO2=oxygen saturation.

The percentage success of blind intubation with the I-Gel supraglottic device is low, 23%, consistent with the results of blind intubation trials.⁴ If the various groups studied are analyzed separately, the success rate is higher in the group of patients with a body weight between 25 and 35 kg, using the I-gel #2.5 mask. The intubation success in this group may be associated with the similarity of the airway anatomy of these patients and the adult patients. No relationship was found between the fiberoptic view and the blind intubation success. Among the intubated patients, 44.4% had ideal view, 33.3% high view, and 22.2% low view, according to the Cook and Cranshaw scale.¹¹ The I-Gel laryngeal mask has excellent ventilation rates, 100% of the patients in this group were ventilated, with seal pressures of around 20cmH2O, a pressure similar to that reported in clinical trials.^2-6,12

We believe that one of the strengths of the study was the inclusion of 4 different pediatric populations separated by body weight ranges. Moreover, the goal ofblind intubation was a significant clinical outcome, which could improve airway management safety.

Other strengths included the ability to evaluate the fiberoptic vision through the I-gel mask and establish a correlation with the success of the intubation. Moreover, the fact that the investigators did not have a learning curve for blind intubation resulted in mask insertion conditions and intubation attempts that were closer to real-life situations.

We also noticed that the I-gel device is a good intubation guide through the fiberoptic bronchoscope, as the rate of ideal and low view that facilitates access of the fiberoptic bronchoscope through the glottis and insertion into the airway to complete the orotracheal intubation was 70%. This is an acceptable value to recommend the use of the Igel supraglottic device as a guide for fiberoptic bronchos-copy-based orotracheal intubation. This is in fact the current recommendation.

The limitations we identified in the study were the inclusion of patients classified above ASA II; the size of the balloon-less orotracheal tubes recommended by the manufacturer for each I-gel was usually small for the patient's airway, facilitating the development of leaks in patients achieving a successful intubation. Moreover, none of the patients in the study met the difficult airway criteria; hence, the results in terms of the percentage of successful intubations may not be extrapolated to difficult airways. There was no learning curve for blind intubation in real-life patients, only simulation that could have influenced the device performance.

In summary, we are of the opinion that the I-gel supraglottic device is not a good choice for blind intubation in the pediatric population, particularly sizes 1,1.5, and 2. The performance improves with the I-gel #2.5 (50% effectiveness); however, it is not as successful as in adults. It is however a suitable device for positive pressure ventilation, with a seal pressure of around 20 cmH₂O and it also helps as a canal for glottis visualization using fiberoptic bronchoscopy, in addition to having a gastric suction canal, except for mask #1.

Protection of human and animal subjects: The authors declare that the procedures followed were in accordance with the regulations of the relevant clinical research ethics committee and with those of the Code of Ethics of the World Medical Association (Declaration of Helsinki).

Confidentiality of data: The authors declare that they have followed the protocols of their work center on the publication of patient data.

Right to privacy and informed consent: The authors have obtained the written informed consent of the patients or subjects mentioned in the article. The corresponding author is in possession of this document.