HE ABC’S - AIRWAY
# = fracture
most acute airway problems in an unconscious patient can be managed using simple techniques such as:
• 100% O2 with the patient in the lateral position (contraindicated in known suspected C-spine #)
• head tilt via extension at the atlanto-occipital joint ...
GENERAL ANESTHETIC AGENTS. . . . . . . . . . . 14
Definition of General Anesthesia
IV Anesthetics (Excluding Opioids)
Narcotics/Opioids
Volatile Inhalational Agents
Muscle Relaxants + Reversing Drugs
MCCQE 2002 Review Notes Anesthesia – A1
, THE ABC’S - AIRWAY
❏ # = fracture
❏ most acute airway problems in an unconscious patient can be managed using simple techniques such as:
• 100% O2 with the patient in the lateral position (contraindicated in known suspected C-spine #)
• head tilt via extension at the atlanto-occipital joint (contraindicated in known/suspected C-spine #)
• jaw thrust via subluxation of temporomandibular joint (TMJ)
• suctioning (secretions, vomitus, foreign body)
• positioning to prevent aspiration
• inserting oro- or naso-pharyngeal airway
❏ nasopharyngeal airway indicated when an oropharyngeal airway is technically difficult
(e.g. trismus, mouth trauma)
• large adult 8-9 mm, medium adult 7-8 mm, small adult 6-7 mm internal diameter
❏ complications of nasopharyngeal airway include
• tube too long - enters the esophagus
• laryngospasm
• vomiting
• injury to nasal mucosa causing bleeding and aspiration of clots into the trachea
❏ oropharyngeal airway holds tongue away from posterior wall of the pharynx
• large adult 100 mm, medium adult 90 mm, small adult 80 mm
• facilitates suctioning of pharynx
• prevents patient from biting and occluding endotracheal tube (ETT)
❏ complications of oropharyngeal airway include
• tube too long - may press epiglottis vs. larynx and obstruct
• not inserted properly - can push tongue posteriorly
❏ more advanced techniques include
• tracheal intubation (orally or nasally)
• cricothyroidotomy
• tracheostomy
TRACHEAL INTUBATION
❏ definition: the insertion of a tube into the trachea either orally or nasally
Indications for Intubation - the 5 P's
❏ Patency of airway required
• decreased level of consciousness (LOC)
• facial injuries
• epiglottitis
• laryngeal edema, e.g. burns, anaphylaxis
❏ Protect the lungs from aspiration
• absent protective reflexes, e.g. coma, cardiac arrest
❏ Positive pressure ventilation
• hypoventilation – many etiologies
• apnea, e.g. during general anesthesia
• during use of muscle relaxants
❏ Pulmonary Toilet (suction of tracheobronchial tree)
• for patients unable to clear secretions
❏ Pharmacology also provides route of administration for some drugs
Equipment Required for Intubation
❏ bag and mask apparatus (e.g. Laerdal/Ambu)
• to deliver O2 and to manually ventilate if necessary
• mask sizes/shapes appropriate for patient facial type, age
❏ pharyngeal airways (nasal and oral types available)
• to open airway before intubation
• oropharyngeal airway prevents patient biting on tube
❏ laryngoscope
• used to visualize vocal cords
• MacIntosh = curved blade (best for adults)
• Magill/Miller = straight blade (best for children)
❏ Trachelight - an option for difficult airways
❏ Fiberoptic scope - for difficult, complicated intubations
❏ Endotracheal tube (ETT): many different types for different indications
• inflatable cuff at tracheal end to provide seal which permits positive pressure ventilation and
prevents aspiration
• no cuff on pediatric ETT (physiological seal at level of cricoid cartilage)
• sizes marked according to internal diameter; proper size for adult ETT based on assessment of patient
• adult female: 7.0 to 8.0 mm
• adult male: 8.0 to 9.0 mm
• child (age in years/4) + 4 or size of child's little finger = approximate ETT size
• if nasotracheal intubation, ETT 1-2 mm smaller and 5-10 cm longer
• should always have ETT smaller than predicted size available in case estimate was inaccurate
❏ malleable stylet should be available; it is inserted in ETT to change angle of tip of ETT, and to
facilitate the tip entering the larynx; removed after ETT passes through cords
❏ lubricant and local anaesthetic are optional
❏ Magill forceps used to manipulate ETT tip during nasotracheal intubation
❏ suction, with pharyngeal rigid suction tip (Yankauer) and tracheal suction catheter
❏ syringe to inflate cuff (10 ml)
A2 – Anesthesia MCCQE 2002 Review Notes
, THE ABC’s - AIRWAY . . . CONT.
❏ stethoscope to verify placement of ETT
❏ detector of expired CO2 to verify placement
❏ tape to secure ETT and close eyelids
❏ remember “SOLES”
Suction
Oxygen
Laryngoscope
ETT
Stylet, Syringe
Preparing for Intubation
❏ failed attempts at intubation can make further attempts difficult due to tissue trauma
❏ plan and prepare (anticipate problems!)
• assess for potential difficulties (see Preoperative Assessment section)
❏ ensure equipment (as above) is available and working e.g. test ETT cuff, and means to deliver
positive pressure ventilation e.g. Ventilator, Laerdal bag, light on laryngoscope
❏ preoxygenation of patient
❏ may need to suction mouth and pharynx first
Proper Positioning for Intubation
❏ FLEXION of lower C-spine and EXTENSION of upper C-spine at atlanto-occipital joint (“sniffing position”)
❏ "sniffing position" provides a straight line of vision from the oral cavity to the glottis
(axes of mouth, pharynx and larynx are aligned)
❏ above CONTRAINDICATED in known/suspected C-spine fracture
❏ once prepared for intubation, the normal sequence of induction can vary
Rapid Sequence Induction
❏ indicated in all situations predisposing the patient to regurgitation/aspiration
• acute abdomen
• bowel obstruction
• emergency operations, trauma
• hiatus hernia with reflux
• obesity
• pregnancy
• recent meal (< 6 hours)
• gastroesophageal reflux disease (GERD)
❏ procedure as follows
• patient breathes 100% O2 for 3-5 minutes prior to induction of anesthesia (e.g. thiopental)
❏ perform "Sellick's manoeuvre (pressure on cricoid cartilage) to compress esophagus, thereby
preventing gastric reflux and aspiration
• induction agent is quickly followed by muscle relaxant
(e.g. succinylcholine), causing fasciculations then relaxation
• intubate at time determined by clinical judgement - may use end of fasciculations if no defasciculating
neuromuscular junction (NMJ) Blockers have been given
• must use cuffed ETT to prevent gastric content aspiration
• inflate cuff, verify correct placement of ETT, release of cricoid cartilage pressure
• manual ventilation is not performed until the ETT is in place and cuff up
(to prevent gastric distension)
Confirmation of Tracheal Placement of ETT
❏ direct
• visualization of tube placement through cords
• CO2 in exhaled gas as measured by capnograph
• visualization of ETT in trachea if bronchoscope used
❏ indirect (no one indirect method is sufficient)
• auscultate axilla for equal breath sounds bilaterally (transmitted sounds may be
heard if lung fields are auscultated) and absence of breath sounds over epigastrium
• chest movement and no abdominal distension
• feel the normal compliance of lungs when bagging patient
• condensation of water vapor in tube during exhalation
• refilling of reservoir bag during exhalation
• AP CXR: ETT tip at midpoint of thoracic inlet and carina
❏ esophageal intubation is suspected when
• capnograph shows end tidal CO2 zero or near zero
• abnormal sounds during assisted ventilation
• impairment of chest excursion
• hypoxia/cyanosis
• presence of gastric contents in ETT
• distention of stomach/epigastrium with ventilation
MCCQE 2002 Review Notes Anesthesia – A3
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