Mount Sinai Expert Guides. Группа авторов

       After ensuring proper preparation, equipment set‐up, functioning monitors, positioning and preoxygenation, the patient is typically administered an apnea‐inducing medication as well as a paralytic agent, both of which are chosen based on patient conditions as well as the clinical situation. It should also be noted that in certain conditions such as cardiac arrest, induction agents may not be necessary.

       When the patient is deemed appropriately anesthetized, the laryngoscope is held in the provider’s left hand while the right hand opens the patient’s mouth using his or her thumb and index finger in a scissoring motion. The laryngoscope is then inserted into the mouth using care not to damage the patient’s lips or teeth. In the case of the curved MAC blade, the tongue is swept to the left and the tip of the blade placed in the vallecula just anterior to the epiglottis, while the straight Miller blade is inserted in midline position beneath the epiglottis. The handle of the laryngoscope is lifted upwards and anteriorly, exposing the vocal cords. The handle should never be tilted backwards as this can result in dental damage. The ETT is then inserted through the vocal cords under direct visualization. After ETT insertion, the stylet (if used) is removed as is the laryngoscope. The pilot balloon is then inflated with air using a 10 mL syringe to no more than 30 mmHg of pressure.

       To confirm tracheal placement, the ETT is connected to a bag ventilation circuit and ventilated, observing bilateral chest rise, condensation in the ETT, and, most importantly, continuous end‐tidal CO2 via capnography – considered the gold standard. If continuous end‐tidal CO2 is not detected, esophageal intubation should be suspected and laryngoscopy should be reattempted.

       The distal tip of the ETT should lie beyond the vocal cords but above the carina, avoiding mainstem intubation. In adults this typically correlates to 21–23 cm at the patient’s lip. A CXR should be ordered immediately after placement to confirm proper position.

        Video 1.1 demonstrates a successful endotracheal intubation of a morbidly obese patient. Note the ready availability of all necessary equipment including suction, laryngoscope, ETT, and oral airway. Also, note the proper patient positioning, including approximately 35° cervical flexion aided by the use of multiple blankets to ramp the shoulders as well as slight head extension. This combination allows for a nearly straight line of sight from the open mouth to the trachea. A MAC blade is used in the left hand and it sweeps the tongue to the side after the right hand scissors the mouth open. The blade is placed in the vallecula. Force is applied in a 45° direction to visualize the glottis opening, not rocked back against the upper incisors. The ETT is directly visualized as it passes between the vocal cords. The laryngoscope is then removed, and the ETT cuff is inflated with no more than 10 mL of air. While bilateral breath sounds and presence of fog in the ETT should indicate proper placement, the gold standard for proper placement is continuous end‐tidal CO2 waveform capnography.

       This is a specialized method of induction used when the risk of pulmonary aspiration is particularly high.

       The goal is to achieve optimal intubating conditions in the fastest time possible.

       After preoxygenation, cricoid pressure is held by an assistant while induction agents (see Chapter 2 for agents and dosages) are given followed by 1.5 mg/kg of succinylcholine or 1 mg/kg of rocuronium, and laryngoscopy is attempted without mask ventilation. Cricoid pressure is maintained until confirmation of tracheal intubation is observed.

       Most difficult airways can be anticipated, and care should always be taken to recognize them with proper assessment, as unanticipated airway difficulties subject the patient to potential hypoxia, cardiovascular collapse, and neurologic damage.

       A distinction should be made as to whether the potential difficulty lies in the ability to mask ventilate, to intubate, or both.

       A good rule of thumb is to never intentionally make a patient apneic unless one is certain that ventilation will be possible.

       Proper planning and set‐up, availability of equipment, positioning, and adequate preoxygenation become even more important when airway difficulty is suspected.

       In the setting of an anticipated difficult airway, additional tools such as video laryngoscopes, fiberoptic bronchoscopes as well as additional providers with the ability to provide surgical airway access should be immediately available prior to induction.

       If intubation and mask ventilation are predicted to be difficult, airway topicalization with local anesthetic and fiberoptic intubation while awake with minimal sedation is the gold standard. This should be performed with an open emergency tracheostomy set nearby as well as a provider capable of performing a surgical airway procedure. One may also attempt an ‘awake look’ by titrating small doses of a non‐apnea‐inducing hypnotic‐like ketamine until a brief exam under video or direct laryngoscopy is tolerated. If this view is acceptable, one can then induce as usual and intubate the patient with the particular device.

       In the undesirable scenario where intubation is found to be difficult after induction (unanticipated difficult intubation), an attempt should be made to mask ventilate the patient and assistance should be called. If mask ventilation is easy, one can then attempt another method of intubation while confirming proper positioning and bed height. If mask ventilation is difficult, one should attempt the two‐handed mask ventilation technique or placement of an oral airway. If still difficult, supraglottic airway placement such as an LMA should be considered. If ventilation remains poor, emergency invasive airway placement is likely required.

       Cervical spine injury, whether due to trauma, previous cervical fusion resulting in limited mobility, or inflammation from rheumatoid arthritis can present challenges for airway management. The presence of a cervical collar can also make airway management difficult. Evaluation of cervical flexion and extension is prudent, and, in the case of trauma, discussions with spine surgeons regarding cervical spine stability should take place.

       In the setting of an unstable cervical spine injury, intubation with a fiberoptic bronchoscope should take place. Alternatively, direct laryngoscopy while an assistant performs inline stabilization (holding the head firmly with both hands so as to not allow unintentional cervical flexion or extension by the laryngoscopist) may be attempted.

       While the decision to extubate is partly driven by objective data, it also relies upon clinical judgment.

       Patients should have stable vital signs, an SpO2 of at least 90% or an FiO2 of 40% or less, PaCO2 <50 mmHg