To be skillful at the airway management, the provider must know the important anatomical, physiological, and pathological features related to the airway as well as knowledge of the various tools and methods that have been developed for this purpose. They also should know the differences between the adult, pediatric, and neonatal airways and be well-versed on other difficult airways as these differences could impact on the safe and effective control of the airway.
The Four Principals of Airway Management in ACLS (Advanced Cardiovascular Life Support)
The pediatric airway (Harless) is narrower at the subglottic area and is cephalad and more anteriorly when compared to the adult airway, which is narrower at the glottis. Children 12 years or younger have a smaller cricothyroid membrane, and their larynx is compliant, funnel-shaped and rostral in position. The larger occiput combined with a shorter neck makes laryngoscopy relatively more difficult by providing obstacles to the alignment of the oral, laryngeal, and tracheal axes. A folded towel is often required as a shoulder roll to achieve a neutral position of the neck and open up the airway. The location of the vallecula is vital for all healthcare workers who perform intubation. It is an important anatomical landmark during oral intubation of the trachea. In order to visualize the vallecula, the blade of the Macintosh laryngoscope is placed on to the vallecula and depressed to see the glottis. If the vallecula is not visualized during intubation, the risk of esophageal intubation is high. Place the ET tube after visualization of the glottis. The dimensions of the trachea are dependent on the age and sex of the child. Please see Table 1. There are different formulas to select the proper size of the endotracheal tube (ET).
For children aged 1 month to 6 years, ultrasound measurement of subglottic airway diameter better predicted appropriately sized ET than traditional formulas using age and height (Masayuki Shibasaki). Cuffed ET tubes are preferable to decrease the air leak, pressure necrosis in ventilated patients, as the incidence of laryngospasm is higher with uncuffed ET tubes. Glideslope is a recent adjuvant in airway management that helps in proper visualization of the airway.
Table 1: Tracheal Dimensions to the 20th Birthday: Males and Females Shown Separately at Age 14 and Older
(N. Thorne Gnscom)
Indications for intervening to secure the airway include respiratory failure, apnea, reduced level of consciousness (GCS less than or equal to 8), rapid change of mental status, airway injury or impending airway compromise, high risk for aspiration, or ‘trauma to the box', which includes all penetrating injuries to the abdomen or chest cavity.
The only absolute contraindication to surgical cricothyroidotomy is age, although the exact age at which a surgical cricothyrotomy can be safely performed is controversial and has not been well defined. Various sources list lower age limits ranging from 5 years to 12 years, and Pediatric Advanced Life Support (PALS) defines the pediatric airway as age 1-8 years.
Airway Position and Clearance
Upper airway obstruction is often relieved by head tilt, chin lift, or jaw thrust. In infants and children, a simple suctioning of the airway will help with the clearance. The suction can be done using a bulb syringe or any other mechanical suction device. When using a bulb syringe to suction an infant, it is important to suction the mouth before the nose to avoid aspiration. The first step is to depress the bulb syringe and then place it in the mouth and nose. Infants are prone to vagal stimulation, and suctioning can lead to bradycardia. Suction must not last for more than 10 seconds.
Adjuvants to Upper Airway Obstruction
Oropharyngeal airway: This cannot be used in patients with intact gag reflux or oral trauma. Different sizes are available. The size is measured from the lip to the angle of the jaw. When appropriately measured and used it is very useful for patients with spontaneous respirations but needed help to keep their airway open.
Nasopharyngeal airway: It has advantages over the oropharyngeal airway (OPA) as it can be used in patients with an intact gag reflex, trismus or oral trauma. The important factor in sizing a nasopharyngeal airway (NPA) is not the width of the tube but rather the length of the subject. The average adult male needs a size 7 port and average female needs a size 6 port. A tall male requires size 8, and a tall female requires size 7.
In a study of 413 infants under 12 months found an association between subject height and nares-vocal cord distance. In order to place the NPA in infants, the insertion length must, therefore, be slightly less than the anthropometric measurement of nose tip-earlobe distance.
The fundamental maneuver in airway management is properly performed mask ventilation. Both in adults and pediatrics, there are one- and two-hand techniques. For neonatal airway one hand technique is enough. Upper airway obstruction that may be encountered during simple mask ventilation is often relieved by head tilt, chin lift, jaw thrust, and the application of continuous positive airway pressure. Bag-mask ventilation is also appropriate while preparing to intubate.
Examples are laryngeal mask airway, laryngeal tube, esophageal-tracheal (combi tubes), and endotracheal tube.
Laryngeal mask airway: A relatively recent advancement is the development of the supra-glottic airway. Many devices exist. Two of the more popular supra-glottic devices, the classic laryngeal mask airway (LMA) and pro-seal LMA, have good data in the pediatric population to support their safety and efficacy. It is recommended to use a manometer to gauge the inflation pressure of the cuff of the LMA. LMA still is associated with an increased incidence of respiratory complications when used in children with a recent upper respiratory infection as compared to healthy children.
Esophageal-Tracheal tube and Endotracheal Intubation
This is one of the supraglottis airways now frequently used by many emergency medical personnel. They are popular because of their ease of administration. They come in different sizes, but their routine use did not extend to the pediatric airway management.
Rapid-sequence induction accompanied after pre-oxygenation with cricoid pressure and in-line cervical stabilization, followed by direct laryngoscopy (DL), is the safest and most effective approach.
The gold standard for assessing placement of an ET is direct visualization with the help of laryngoscope. Carbon dioxide detectors are indicated for confirmation of endotracheal tube placement in the trachea. The AHA (American Heart Association) recommends continuous waveform capnography in addition to clinical assessment as the most reliable method of confirming and monitoring correct placement of an ET tube. Bedside mobile ultrasound is another resource that some emergency departments have to confirm the position of the ET tube. A chest x-ray is used frequently to assess the placement of the ET. The ET tube should be placed 2 centimeters above the carina. In many cases, when blind endotracheal intubation takes place, the tube may go down the right mainstem bronchus. Once an x-ray has been done, the condition is recognized, and the tube can be pulled back. It may present with absent breath sounds on the left chest with low oxygen saturation. After the intubation, the ETT should be secured properly, and the placement is monitored continuously.
Airway Management in Traumatic Patients
Trauma is leading cause of morbidity and mortality worldwide especially for people aged 15 to 29. Trauma is the second-most common single cause of death, representing 8% of all deaths. The World Health Organization estimates that traumatic injuries from traffic accidents, drowning, poisoning, falls, burns, and violence kill more than five million people worldwide annually, with millions more suffering from the consequences of injuries.
Rapid evacuation and transportation to a trauma center improve the outcome in severely injured patients. Prehospital intubation in the experienced hands does not contribute to the increased transport times. These patients need to be monitored and transported quickly and safely to the nearest trauma facility.
The only absolute contraindication to surgical cricothyroidotomy is age, although the exact age at which a surgical cricothyrotomy can be safely performed is controversial and has not been well defined. Various sources list lower age limits ranging from 5 to 12 years, and Pediatric Advanced Life Support (PALS) defines the pediatric airway as age 1 to 8 years.
When intubating a patient who suffered injuries to the chest, pay attention to the complications that could arise after the intubation like tension pneumothorax or air leak from a bronchial injury. Patients with pneumothorax should have a chest tube prior to the intubation. In cases of bronchial injury, a massive air leak can be precipitated by intubation. Sometimes the segment of the damaged lung may have to be occluded with a bronchial blocker to avoid air escape.