We are sorry, but we are not currently accepting applications for postings.
In addition, you can continue to use the publications you have published until now.

Clinical Research
Clinical Medicine
Medical Devices

Importance of size of the Guedel in the patency of the airway during MRI in children

Ramón Reina1 , Jusset T García2 , Ana Lomas3


The permeability of the pediatric airway is critical if intubation is not desired in radiological diagnostic procedures such as MRI and others. We present the effect of the tube oropharyngeal (Guedel) on the airway by size. This project was completed without previously selecting the patients. It formed part of a normal day´s work. Patients were heavily sedated, maintaining their natural breathing, while on the MRI operating table.

Author and Article Information

Author info
1. Department of Anesthesiology. Children’s Hospital Virgen del Rocío. Seville. Spain.
2. M.D. Department of Anesthesiology. Virgen de Valme Hospital. Seville. Spain.
3. M.D. Department of Anesthesiology , Virgen del Rocío Hospital , Seville. Spain

RecievedSep 6 2013  AcceptedNov 22 2013  PublishedDec 4 2013

CitationRamón Reina González , Jusset Teresa García , Ana Lomas (2013) Importance of size of the Guedel in the patency of the airway during MRI in children. Science Postprint 1(1): e00006. doi:10.14340/spp.2013.12C0001

Copyright©2013 The Authors. Science Postprint published by General Healthcare Inc. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs 2.1 Japan (CC BY-NC-ND 2.1 JP) License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

FundingThe authors has not been funded by any Foundation or other non-governmental source that has received funding from any organization with a real or potential interest in the subject matter, materials, equipment or devices discussed, or in any competing product or subject.

Competing interestsNo relevant competing interests were disclosed.

Ethics statementWe obtained permission from the parents during the pre-anesthetic consultation, to carry out the MRI and the sedation, as well as to take images and use them for scientific purposes. This work doesn’t form part of any study or trial; it is part of our daily work.

Reina Gonzalez. R.(MD): anesthesiologist responsible for anesthetic management
Lomas Lozano, A (MD): anesthesiologist assistant
Jusset T García M.T(MD): anesthesiologist assistant

Corresponding authorRamón Reina González
AddressDepartment of Anesthesiology. Children’s Hospital Virgen del Rocío. Avda. Manuel Siurot s/n. Seville. Spain. 41013
E-mailIf you want to contact author,Please register as a member.


During the accomplishment of certain diagnostic procedures under sedation or general anesthesia without endotracheal intubation with preservation of the spontaneous breathing, there is a risk of partial or complete airway obstruction (Image A)1. This situation requires the use of supraglottic devices to keep the airway clear and the tongue in place. Among the available devices the most commonly used in clinical practice is the Guedel Airway. The design of these instruments has significant implications, especially in pediatric anesthesia.2, given that, in order to use the Guedel Airways it is necessary to choose the adequate size. The inadequate size may result in deleterious effects resulting from obstruction of the upper airway. Our aim is to demonstrate the importance of proper selection of the Guedel airway size, using these figures which have significant teaching value. In the images sequence (drawn from the daily anesthetic practice), are described the effects of the insertion of an adequate size (Image B) and an inadequate size (Images C and D) of Guedel Airways. The images relate to patients who underwent MRI secondary to neurological disease. For proper management of the airway it is critical to calculate the size of the Guedel Airway. The adequate size or length of the airway is determined by the distance between the mouth corner and the earlobe of the patient3. Guedel Airways are only indicated in unconscious patients, because of the likelihood that the device would stimulate a gag reflex in conscious or semiconscious patients. This could result in vomiting and potentially lead to an obstructed airway.

Materials and Methods

Patients´ diagnosis included psychomotor development problems, convulsions, brain damage relating to Stuart Weber disease, periependy and periependimarial haemorrhage, brain tumor, etc. Patients were studied during the pre-anesthetic consultation, where permission was obtained from the parents to carry out the mentioned test, as well as to take images and use them for scientific purposes. Following the standard cardiac monitoring and peripheral saturation of oxygen by pulseoximetry, the sedation by face mask took place using a mix of oxygen/air at 50% and sevoflurane, increasing doses (3-4%) until a level of sedation was reached (which would maintain spontaneous breathing and be sufficient to arrange the Guedel airway without causing a reflexive response). The Guedels, adjusted for the weight and size of the patient, were placed in the oral cavity, facing upwards at first, and then turned 180 degrees into their normal downward-facing position. Many pediatric patients had macroglossia so the Guedels did not properly adjust. In those cases, the oropharingeal tube was selected taking into account the patient’s oral cavity size (and not according to the weight or size of the patient).

Results and Discussions

Once the Guedels were fitted (and, while the patients maintained spontaneous breathing, the saturation by pulseoximetry ranged between 97-100% and the heartbeat was stable), a mask with straps - appropriate to the patient´s age- was fitted. Through this mask, oxygen/air/sevoflurane was administered, and C02 was captured and monitored (Fig E). The scan then began. In the lateral and digital sections of the cranium, as found by the MRI scan accidentally, some Guedels were small and pushed the tongue back without obstructing the airway (Fig C). Others were long and ended up touching the epiglottis, also without obstructing the airway (Fig D). Others stayed correctly situated (Fig B). Finally, in others cases, the scan was completed with the patient awake or lightly sedated. In these cases (in which the Guedel was not required), the tongue fell back and seemed to obstruct partially the airway (Fig A), so the children were breathing through their noses. There were no complications in any cases. The patients maintained a moderate to deep hypnosis (except in A), with spontaneous breathing and oxygen saturation between 97-100%. Patients were requested to fast for over six hours before the scan took place. This, together with the state of deep sedation, prevented them from vomiting. If there had been a case or nausea or vomit, the contents of the mouth would had been removed via a tube connected to an aspirator.
The laryngeal mask is more aggressive in the anesthetic management outside the operation room; therefore the Guedel airway is used in order to be as less harmful as possible. However, laryngeal masks are available and they are used depending on the anesthesiologist criteria.


  1. von Ungern-Sternberg BS, Erb TO, Frei FJ. Management of the upper airway in spontaneously breathing children. A challenge for the anaesthetist. Anaesthesist. 2006; 55:164- 70.
  2. Davies JA, Maquire AM. Variability in Guedel airway design Anaesthesia. 2006; 61:297-8.
  3. Bould MD, Thomas ML, Stylianou M. Variability of Guedel-type airways. Anaesthesia. 2006; 61:1125-6.
  • General
  • Innovation
  • Advancement
  • Industry