May 22, 2021
Medical science arguably took its biggest leap with the discovery of anesthesia. The role of anesthesia in numbing out a part of the body or the entire body helped on carrying out surgical procedures with ease without the patient feeling any pain. General anesthesia is when a surgical procedure too invasive to carry out requires the entire body to be numbed. In contrast, local anesthesia is when only the concerned surgical area is numbed while the patient is still awake and in his or her senses.
The effect of anesthesia is such that it relaxes all the muscles of the body and the person no longer has any control over his or her body. The subsequent loss of consciousness makes the tongue of the person fall back, blocking the airway as the person lies down. In order to avoid this, airway management becomes key while the patient is unconscious. It is important to keep the lungs functional during the surgical procedure. Hence, to bring the lungs directly in contact with the external environment, airway management devices were fabricated.
In order to understand the mechanism of airway devices it is important to briefly understand the key structures of the respiratory system through the mouth. Upon depressing the tongue with a device known as laryngoscope, the "glottis" can be seen which leads to the trachea or the wind pipe. The airway devices can either be passed above or below the glottis. The supraglottic devices include tubes that are connected to laryngeal masks. These laryngeal masks help keep the airway open during the surgical procedure.
Advances in laryngeal masks and tracheal tubes both design-wise and shape-wise have better facilitated the management of airway during surgeries. These advances are such that they try to mimic the structures of the airway so that the biocompatible material can be pushed with ease inside the wind pipe. One such technology is the I-Gel, which is a supraglottic device.
The I-Gel, as the name suggests is made of a gel-like structure called the thermoplastic elastomer. It is free of latex, sterile and can be used once in a patient. Its greatest advantages lies in the fact that is can be pushed easily inside the respiratory channel. The head of the I-Gel is designed in a way that is corresponds to the tongue, glottis, various folds and tissues and cartilages as it passes down the throat. A tube connects the head that corresponds to an arbitrary bite block and buccal cavity stabilizer. These act as reference points once the I-Gel is fixed in its final position. The I-Gel also consists of a gastric vent that helps in emptying of any gas that is present in the stomach.
The use of I-Gel in adults can be done in airway management during emergencies, resuscitation, maintaining patent airway and in cases where intubation is difficult. In children, the I-Gel has not been used too often and data is lacking for the same. The I-Gel comes in seven sizes, and it is often postulated that pediatric use will soon come into play because of the versatility of tne device.
I-Gel should not be used in patients with locked jaws, non-fasted patients, inadequate delivery of anesthesia, in procedures that last more than 4 hours, conscious or semi-conscious patients, pregnancy, hernia, etc. The I-Gel should not be reprocessed if insertion is not done in the first attempt. Usually, a trained professional will take only five seconds to position the I-Gel.
The I-Gel is held from the farthest point of the tube. Touching the gel-like cuff should be avoided unless it needs to be lubricated. The insertion is started only after the lubrication which allows free movement of the airway device. Once the pre-medication is done, the patient's neck is extended and the chin pressed down. During this, the fingers will not enter the oral cavity. Later, keeping the chin depressed, the I-Gel is inserted.
At the end of the surgery, during the deeper stages of anesthesia or after the patient immediately regains consciousness, the I-Gel is removed. The patient is asked to open his or her mouth wide enough to easily remove the device. It is important to note that the device should not be pushed vertically in a forceful manner.
The I-Gel is a modern advancement in airway management. Its anatomic design and easy usage across all age groups can help in easy insertion. Color coding of the device helps in guiding which device should be used in which age group based on the weight of the patient.