TY  - CHAP
M1  - Book, Section
TI  - Chapter 19. Airway Management
A1  - Butterworth, John F.
A1  - Mackey, David C.
A1  - Wasnick, John D.
Y1  - 2013
N1  - 
T2  - Morgan & Mikhail's Clinical Anesthesiology, 5e
AB  - Improper  face  mask  technique  can  result  in  continued  deflation  of  the  anesthesia  reservoir  bag  when  the  adjustable  pressure-limiting  valve  is  closed,  usually  indicating  a  substantial  leak  around  the  mask.  In  contrast,  the  generation  of  high  breathing  circuit  pressures  with  minimal  chest  movement  and  breath  sounds  implies  an  obstructed  airway  or  obstructed  tubing.  The  laryngeal  mask  airway  partially  protects  the  larynx  from  pharyngeal  secretions,  but  not  gastric  regurgitation.  After  insertion  of  a  tracheal  tube  (TT),  the  cuff  is  inflated  with  the  least  amount  of  air  necessary  to  create  a  seal  during  positive-pressure  ventilation  to  minimize  the  pressure  transmitted  to  the  tracheal  mucosa.  Although  the  persistent  detection  of  CO2  by  a  capnograph  is  the  best  confirmation  of  tracheal  placement  of  a  TT,  it  cannot  exclude  bronchial  intubation.  The  earliest  evidence  of  bronchial  intubation  often  is  an  increase  in  peak  inspiratory  pressure.  After  intubation,  the  cuff  of  a  TT  should  not  be  felt  above  the  level  of  the  cricoid  cartilage,  because  a  prolonged  intralaryngeal  location  may  result  in  postoperative  hoarseness  and  increases  the  risk  of  accidental  extubation.  Unrecognized  esophageal  intubation  can  produce  catastrophic  results.  Prevention  of  this  complication  depends  on  direct  visualization  of  the  tip  of  the  TT  passing  through  the  vocal  cords,  careful  auscultation  for  the  presence  of  bilateral  breath  sounds  and  the  absence  of  gastric  gurgling  while  ventilating  through  the  TT,  analysis  of  exhaled  gas  for  the  presence  of  CO2  (the  most  reliable  automated  method),  chest  radiography,  or  use  of  fiberoptic  bronchoscopy.  Clues  to  the  diagnosis  of  bronchial  intubation  include  unilateral  breath  sounds,  unexpected  hypoxia  with  pulse  oximetry  (unreliable  with  high  inspired  oxygen  concentrations),  inability  to  palpate  the  TT  cuff  in  the  sternal  notch  during  cuff  inflation,  and  decreased  breathing  bag  compliance  (high  peak  inspiratory  pressures).  The  large  negative  intrathoracic  pressures  generated  by  a  struggling  patient  in  laryngospasm  can  result  in  the  development  of  negative-pressure  pulmonary  edema  even  in  healthy  patients.  
SN  - 
PB  - The McGraw-Hill Companies
CY  - New York, NY
Y2  - 2022/08/08
UR  - accessanesthesiology.mhmedical.com/content.aspx?aid=57232558
ER  -