Airway Approach Algorithm (Rosenblatt)
Two very important airway decision-making factors are the anesthesiologist's
- experience and
ASA-DAA (2003) and ASA-DAA(LMA) apply not just to difficult, but to all airways.
THE FIVE RIGHT QUESTIONS TO ANSWER
1. Must the airway be controlled?
Must I stop the patient's reliance on his/her own physiologic ventilatory control and force dependence on the success of my own airway/breathing technics?
How dangerous might it be to attempt to take control of your patient's airway/breathing?
Anesthesiologist, who will assume airway responsibility, has most important opinion in controversial situations.
Local or regional anesthesia may avoid need for airway manipulation.
Full airway evaluation always indicated in case of 'conversion' to general anesthesia.
DL currently remains standard of care.
We remain unable to definitively predict diffult DL.
Goal of DL = create line of sight from eye to glottis (glottic opening)
- some mouth opening
- 'sniff' postion
- displacement of tongue (place to put tongue)
TMJ function (normal, allows relaxaton of insertion of tongue)
ASA-DAA (2003) may be entered at "Intubation Attempts After Induction of Anesthesia," or
ASA-DAA(LMA) at "General Anesthesia +/- Paralysis
Face mask: 2 of the following 5 predictive of at least minor difficulty
age > 55
BMI > 26
history of snoring
rescued 16 of 17 cannot intubate/cannot ventilate patients (the 1 not rescued had clotted trachea ) *
factors that may preclude use
mouth too small
mass lesion in upper airway
aspiration risk (stomach not empty) (but Proseal-LMA OK?)
With some experience, the vast majority of patients in whom DL is judged to be difficult can be adequately managed by one of the above three devices
If use of a SLA device may be difficult, then a cannot intubate/cannot ventilate situation after induction would be predictable and ought be avoided by entering
Controversial, varied opinions regarding what defines risk
Use experience and evidenced-based information
Most important when SLA device is a viable alternative to tracheal intubation
Face mask: no protection
LMA: low rate of aspiration in moderate and high risk patients *
Combitube: may be protective
Possible difficult DL plus aspirtation risk (stomach full) suggests enter
If patient cannot tolerate a misjudgment in answering Question 3, then enter
If uncomfortable with evaluation, then choose conservatively and enter
- learn, practice, maintain awake fiberoptic intubation techic
- perform preop fiberoptic exam in select patients
- may be done on hospital ward or in preop holding area
- nasal vasocontstrictor (e.g., oxymetazolone - Afrin) plus topical agent (e.g. lidocaine 4%)
- small fiberscope through nasal cavity to visualize naso and oropharynx to answer:
can larynx be visualized?
is there adequate space for a SLA device?
is there anything to prevent or contraindicate DL?
- (if awake intubation chosen, then partial prep has been done)
Rosenblatt, Airway Approach Algorithm. ASA Annual Meeting Refresher Course Lectures, 2005