Chapter 27 - Airway Management Flashcards
Other term for preoxygenation.
Denitrogenation.
Should be practiced in all cases when time permits.
Significance of the technique of RSI.
Gain control of the airwayin the shortest period of time after ablation of protective airway reflexes with the induction of anesthesia.
Remains the mainstay of the American Society of Anesthesiologists’ difficult airway algorithm.
Awake airway management.
Difficult and failed airway management account for how many percent of anesthetic deaths (in the US)?
2.3%
Table 27-1. ANATOMIC DIFFERENCES BETWEEN THE PEDIA & ADULT AIRWAYS.
Narrowest portion.
Infant/child: cricoid cartilage
Adult: vocal folds
Table 27-1. ANATOMIC DIFFERENCES BETWEEN THE PEDIA & ADULT AIRWAYS.
Epiglottis.
Infant/child: longer, narrower and stiffer.
Table 27-1. ANATOMIC DIFFERENCES BETWEEN THE PEDIA & ADULT AIRWAYS.
Aryepiglottic folds.
Closer to midline in infant/child.
Table 27-1. ANATOMIC DIFFERENCES BETWEEN THE PEDIA & ADULT AIRWAYS.
Vocal folds.
Infant/child: anterior angle with respect to perpendicular axis of larynx.
Table 27-1. ANATOMIC DIFFERENCES BETWEEN THE PEDIA & ADULT AIRWAYS.
Laryngeal cartilage.
Pliable in infant/child.
Function and components of the upper airway
Conducting pathway.
Nasal and iral cavities, pharynx, larynx, trachea, and principal bronchi.
How many cartilages does the laryngeal skeleton have?
9
3 paired.
3 unpaired.
These house the vocal folds, which extend in an anterior-posterior plane from the thyroid cartilage to the arytenoid cartilage.
Serves as the anterior protective housing of the vocal mechanism.
Shield shaped THYROID CARTILAGE.
Which group of muscles move the larynx as a whole?
Extrinsic muscles.
The larynx is innervated by two branches of each _______ nerve.
By each VAGUS nerve: the superior laryngeal and recurrent laryngeal nerves.
The RLN supply all the ____1_____ muscles of the larynx except ____2_____.
- Intrinsic
2. Cricothyroid muscle
Trauma to RLN can result to:
Vocal cord dysfunction.
Result of unilateral RLN injury:
- What happens to airway function?
- Larynx?
- A/w function is unimpaired.
2. Protective role of the larynx in preventing aspiration may be compromised.
The membrane joining the superior aspect of cricoid cartliage and the inferior edge of thyroid cartilage.
Cricothyroid membrane
What is the Length and width of CTM in adults?
L: 8-12 mm
W: 10.4 - 13.7 mm
Identifying the location of CTM.
1.5 fingerbreadths below the laryngeal prominence (thyroid notch).
The central membrane of the CTM.
Conus elasticus
How are incisons or needle punctures be made to the CTM?
It is suggested that any incisions or needle punctures to the CTM be made in its inferior thirdand be directed posteriorly (a posterior probing needle will strike the back side of the ring shaped cricoid cartilage).
Where is the (signet ring shaped) cricoid cartilage located?
At he base of pharynx, suspended by the underside of the CTM.
What is the length of trachea in adults? How many cartilages does it have?
Length in adult is 15 cm and is supported by 17-18 C-shaped cartilages.
The 1st tracheal ring in relationship with the cervical vertebra.
Anterior to C6
The carina in relation to the thoracic vertebra.
T5
Right brochi vs. left bronchi:
- ) Diameter
- ) Angle
R Has larger diameter and deviates from the plane of trachea at a LESS ACUTE ANGLE.
Credit for first use of SGA is given to?
Joseph Thomas Clover
Airway management always begins with?
Evaluation and planning.
TABLE 27-5. TECHNIQUES OF COMMON AIRWAY INDEXES MEASUREMENT
Give 5 (MMATH)
Mouth opening Mallampati score Ability to prognath TMD Head and neck movement
TABLE 27-5. TECHNIQUES OF COMMON AIRWAY INDEXES MEASUREMENT
How to measure TMD?
Measured along a straight line from tip of mentum to thyroid notchin neck extended position.
TABLE 27-5. TECHNIQUES OF COMMON AIRWAY INDEXES MEASUREMENT
How to measure mouth opening?
Interincisor distance (or interalveolus distance when edentulous) with the mouth fully opened.
In general, tracheal intubation should be considered non routine in the following conditions (4):
1 the presence of equally important prioritiesto the management of airway (full stomach or open globe)
2 abnormal airway anatomy
3 emergency
4 direct injury of the upper airway and larynx and/or trachea
Predictors of difficult mask ventilation (4).
High mallampati score, poor mandibular protrusion, hx of radiation therapy to te neck, male.m
TABLE 27-7. ASSESSMENT AND PREDICTABILITY OF DIFFICULT MASK VENTILATION
Criteria for difficult mask ventilation (6).
Inability of anesthesiologist to maintain O2 sat>92%; significant gas leak around face mask; need for > 4L/min gas flow (use of fgf button more than twice); no chest movement; 2 handed mas ventilation needed; change of operator required.
TABLE 27-7. ASSESSMENT AND PREDICTABILITY OF DIFFICULT MASK VENTILATION
Independent risk factors for difficult mask ventilation (5)
Presence of beard; BMI >26ng/m2; edentulous; >55 y/o; hx of snoring.
FiO2 of room air.
0.21
The patient breathing room air will experience desaturation to a level of <90% after approx. how many minutes of apnea?
1-2 minutes.
Pts with pulmonary disease or with conditions affecting metabolism or lung volumes frequently evidence desaturation sooner due to?
Increased o2 extraction, decreased FRC, R-L transpulmonary dysfunction.
What is the most common reason for not achieving a maximum alveolar oxygen store during preoxygenation?
A loose fitting mask, allowing the entrainment of room air.
Methods of preoxygenation (3).
4 VC breaths of 100% O2 over a 30 second period (PaO2 of 339 mmHg); 8 VC breaths over 60 seconds; tight fitting mask for 5 minutes or more of TV.
FGF in the mask should be a minimum of ___ L/min.
10-12
What is pharyngeal insufflation and how is it done?
Oxygen is insufflated at arate of 3L/min via a catheter passed through the nares delays onset of desaturation.
This relies in the technique of apneic oxygenation, a process by which gases are entrained in the alveolar space in presence of a patent airway.
PREOXYGENATION
Delay desaturation in obese patients
Bilevel positive airway pressure
Head up position (25 degrees)
SUPPORT OF THE AIRWAY WITH THE INDUCTION OF ANESTHESIA
Device most commonly used to deliver anesthetic gases and oxygen as well as to ventilate the patient whou has been apneic.
Anesthesia face mask
Effect of anesthesia in the airway.
Drug induced central ventilatory depression and relaxation of the musculature of the upper airway — can rapidly lead to apnea.
SUPPORT OF THE AIRWAY WITH THE INDUCTION OF ANESTHESIA: Anesthesia Face Mask
Airleak around the edges of the mask is prevented by?
Downward pressure
SUPPORT OF THE AIRWAY WITH THE INDUCTION OF ANESTHESIA
Advantages of the sniffing position.
Improves mask ventilation by anteriorizing the base of the tongue and epiglottis.
How is jaw thrust done? What does it doto airway?
Upward displacement of the mandible. Raises the soft tissue of the anterior airway off the pharyngeal wall.
What to do when positive pressure inspiration is succesful, but is not followed by passive gas escape during expiration?
Expiratory chin drop.
The patient with normal lung compliance should require no more than how many cm H2O pressure to inflate the lungs?
20-25
LARYNGOSPASM: Define. Etiology. Complication. Treatment.
A reflex closure of the vocal folds. Occurs from stimulation by FB, saliva, blood, vomitus, touching th glottis or even light plane of anesthesia.
Noncardiogenic pulmonary edema if there is continued spontaneous ventilation against closed vocal cords.
Ttt: removal of stimulus, CPAP, deepening of anesthetic state, rapid acting muscle relaxant.
Blade used to displace the epiglottis out of the line of sight by tensing the glossoepiglottic ligament.
Macintosh (curved) blade
Laryngeal view scoring system.
CORMACK LEHANE
1: visualization of the entire glottic aperture
2: visualization of only the posterior aspect of the glottic aperture
3: tip of epiglottis
4: no more than soft palate
Paramount to safe perioperative care.
Management of the airway.
