An Update on Airway Management

Eugenio Daniel Martinez-Hurtado, María Luisa Mariscal Flores

• Publisher: Bentham Science Publishers
• Year: 2020
• ISBN:
  9789811432385
• Topic: Medicina
• Subtopic: Anestesiología y gestión del dolor

In recent years, there have been many advances in the safe management of the patient's airway, a cornerstone of anesthetic practice. An Update on Airway Management brings forth information about new approaches in airway management in many clinical settings. This volume analyzes and explains new preoperative diagnostic methods, algorithms, intubation devices, extubation procedures, novelties in postoperative management in resuscitation and intensive care units, while providing a simple, accessible and applicable reading experience that helps medical practitioners in daily practice. The comprehensive updates presented in this volume make this a useful reference for anesthesiologists, surgeons and EMTs at all levels. Key topics reviewed in this reference include:· New airway devices, clinical management techniques, pharmacology updates (ASA guidelines, DAS algorithms, Vortex approach, etc.), · Induced and awake approaches in different settings· Updates on diagnostic accuracy of perioperative radiology and ultrasonography· Airway management in different settings (nonoperating room locations and emergency rooms)· Airway management in specific patient groups (for example, patients suffering from morbid obesity, obstetric patients and critical patients)· Algorithms and traditional surgical techniques that include emergency cricothyrotomy and tracheostomy in 'Cannot Intubate, Cannot Ventilate' scenarios.· Learning techniques to manage airways correctly, focusing on the combination of knowledge, technical abilities, decision making, communication skills and leadership· Special topics such as, difficult airway management registry, organization, documentation, dissemination of critical information, big data and databases

An Update on Paediatric Airway Management

Gema Pino Sanz^{1, *}, María Dolores Méndez Marín¹

¹ Department of Pediatric Anesthesiology, Hospital Universitario Doce De Octubre, Madrid, Spain

Abstract

The condition of “cannot intubate cannot ventilate” is very rare and stressful scenario in paediatric patients, requiring a deep knowledge about anatomic and physiologic features as well as their congenital anomalies. Their anatomical differences as compared to adults imply different laryngoscopy techniques and, for this reason, the endotracheal tube placement is more difficult than in adults. Moreover, paediatric patients have increased oxygen consumption and a reduced functional residual capacity, so the apnea time decreases considerably. In healthy infants under the age of 6 months, with the previous preoxygenation, the saturation pulse oximetry reaches 90% in 90 seconds, while in adults, it happens at 6 minutes [1]. The respiratory events are very common in the paediatric population during general anaesthesia induction. There are some risk factors such as age of under 12 months and the experience and skills of the anaesthesiologist [2]. The hypoxemia (airway management) is one of the causes of cardiac arrest in the operating-room (27%), while failed endotracheal intubation appears in 7% of the cases [3]. All paediatric anaesthesiologists should be warned about the anatomical and physiological characteristics of the paediatric airway [4].

Keywords: Combitube, Cricoid pressure, EC position, Extubation, Flexible fiberoptic bronchoscope, Functional residual capacity, Gastric distension, Laryngeal braking, Laryngeal mask airway, Laryngospasm, Light wand, Miller laryngoscope, Sniffing position, Lemon score , Sugammadex, Two hands ventilation, Uncuffed ETT, Videolaryngoscopy.

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^* Corresponding author Gema Pino Sanz: Department of Pediatric Anesthesiology, Hospital Universitario Doce De Octubre, Madrid, Spain; Tel/Fax:[phone]; E-mail:[email protected]

AIRWAY ANATOMY

The anatomical differences between adults and children decrease as the child grows to maturity. In Table 1, the significant characteristics are shown.

The head and the prominent occiput are relatively large with respect to the rest of the body and, a supine position, the neck flexion can produce airway obstruction [5]. The nasal passages are narrower due to lymphoid tissues, increasing the airway resistance.

The hypertrophy of lymphoid tissues in the pharynx can result in airway obstruction when sleeping (obstructive sleep apnea) and in performing laryngoscopy. In addition, the tongue is large and sticks to the palate, causing airway obstruction [6]. The elevation of the head to the “sniffing position” can improve this airway obstruction [1, 7].

The pediatric larynx has a cylindrical shape, not conical as it was assumed, and with an anterior diameter bigger than the transverse diameter. The cricoid ring is the most rigid area and the narrowest airway is in the subglottic area. These characteristics explain the inadequate seal of the uncuffed endotracheal tube (ETT) and do not prevent the ischemic damage caused by the pressure of the lateral walls [8, 9].

The larynx is situated more cephalad (C4) in newborns and then becomes caudal until level C6-C7 in adults [7]. The small cross-sectional area of the infant’s airway increases exponentially the resistance of the airflow; hence it can worsen the breathing.

Epiglottis is relatively long and stiff. It is positioned more horizontal than in adults. In neonates, it is V-shaped and mobile, so a straight-blade laryngoscope is recommended because it can raise the epiglottis with the tip of the blade and improve the endotracheal intubation. At the age of 4- 5 years, the epiglottis is less mobile and smaller and the curve-blade laryngoscope is recommended.

The larynx is situated more cephalad and anteriorly, so this creates an acute angle between the base of the tongue and the larynx; therefore, it is recommended to insert a roll under the shoulder, limiting the excessive flexion and improving laryngoscopy view.

AIRWAY PHYSIOLOGY

The pediatric airway has greater compliance while the connective tissue is poor, leading to a dynamic collapse in case of obstruction. If there is an extra-thoracic obstruction, the collapse occurs during the inspiratory phase, but if there is an intrathoracic disease, the collapse happens during the expiratory phase.

The lung volumes of the children are similar to those of adults, except for the functional residual capacity (FRC), which increases as children grow. This smaller FRC tends to lung collapse, but there are compensatory mechanisms to avoid it, such as rapid respiratory rate, expiration control (“laryngeal braking”) and the tonic activity of the ventilatory muscles. This mechanism is blocked during sleep and general anesthesia.

Table 1 Paediatric Airway Anatomy.

Anatomy	Implication	Management
Prominent occiput Nares small Neck short Lymphoid tissue	Neck flexed in supine position Upper airway obstruction Oral/pharyngeal/laryngeal axes not lined up Laryngoscopy difficult	Shoulder roll Sniff position
Cephalad larynx Large tongue to mouth size	Larynx view more anterior Entire tongue in the oral cavity	Lateral approach to laryngoscopy
Epiglottis angled projecting above the glottic opening	Epiglottis obstructs the view of vocal cords	Straight laryngoscope blade < 3 years old
Larynx cylinder [10] Vocal cords slanted anteriorly and rostrally...