Devices and equipment The Miller laryngoscope is the most commonly used laryngoscope blade for examination of the larynx. Robert A. Miller introduced the Miller Laryngoscopes.
Instruments and instruments.
The Miller laryngoscope is the most commonly used straight laryngoscope blade for examination of the larynx. Robert A. Miller introduced the Miller blade in 1941 when endotracheal intubation was becoming the norm. This design overcame the problems with laryngoscope blades that were common at the time.
The Miller blade was long, rounded at the base, and narrow at the tip, with an additional curve 2 inches from the tip. It was often used in infants because it was relatively large compared to the epiglottis, making it more visible. During laryngoscopy, a spatula is placed behind the epiglottis to reveal the vocal folds and vocal cords.
The Miller blade may be more useful than the McIntosh blade for people with short, thick throats, high larynxes, wide tongues, and obesity. Miller blades are available in sizes 0-5.
Preparation for laryngoscopy
In large animals, a fast of 8-12 hours prior to anesthesia is necessary to reduce the risk of vomiting during induction and recovery from anesthesia. In small animals, this step is not necessary. However, guinea pigs may retain food in the pharynx. If this is observed in a large number of individuals (guinea pigs), a 3-4 hour fast before anesthesia may be sufficient. An examination to determine the health and age of the subject should also be performed before anesthesia.
Laryngoscopy can be performed on subjects under light anesthesia, but it is recommended that this method not be used until the technique is mastered. Prior to endotracheal intubation, the patient should receive oxygen for approximately 2 minutes to delay the onset of hypoxia due to inadvertent laryngeal obstruction. Laryngoscopy can be performed as an emergency diagnostic procedure before surgical correction but is most effective when performed in a stable patient.
Mirror spatula laryngoscopy
Have the person lie on their back.
Hold the laryngoscope in the dominant hand.
Pull the subject’s tongue forward and to the left.
Slowly insert the blade through the right side of the subject’s mouth.
Advance the blade to the middle, halfway to the base of the tongue.
Place the tip of the blade under the epiglottis.
Turn the handle to a 45° angle and apply upward pressure on the tip.
Lift the handle until the vocal folds are visible.
Intubate with the vocal cords directly visible.
Remove the blade while holding the tracheal tube firmly.
Remove the blade from the handle, tighten the valve and rinse the blade with cold tap water to remove any visible debris. After soaking in enzymatic detergent, thoroughly scrub the blade with a soft bristle knife. Rinse again with cold tap water to remove any detergent residue. Dry the blade with a clean, lint-free cloth.
Human bone and soft tissue can affect the appearance of the neck. Improper use of the blade can damage soft tissue and front teeth. Consider the weight of the object when selecting the blade size. Laryngoscope blades and handles should always be checked after cleaning, disinfection and sterilization and before use. The blade handle acts as a counterbalance and should therefore be chosen according to the size of the blade used.