TY  - CHAP
M1  - Book, Section
TI  - Chapter 55. High-Frequency Jet Ventilation (HFJV)
A1  - Albright, Brooke
A2  - Atchabahian, Arthur
A2  - Gupta, Ruchir
Y1  - 2013
N1  - 
T2  - The Anesthesia Guide
AB  - Open  mechanical  ventilation  system  that  may  improve  gas  exchange  at  lower  peak  and  mean  airway  pressures  than  conventional  ventilationPulsed  cycles  of  small  tidal  volumes  (2–5  mL/kg)  at  high  frequencies  (50–150  breaths/min)Inspiration:  via  a  small  cannula  that  delivers  a  jet  stream  of  pulsed  breaths  to  the  lungs.  The  jet  stream  cannula  should  be  small  enough  to  avoid  “sealing”  the  airway.  Typically  the  cannula  is  placed  through  the  vocal  cords  in  the  trachea,  but  in  an  emergency  setting,  a  cannula  or  a  large-bore  Angiocath  can  be  introduced  through  the  cricothyroid  membraneExpiration:  passive  around  jet  nozzleHigh-frequency  jet  ventilation  (HFJV)  parameters  and  settings:Driving  pressure:  major  determinant  of  tidal  volume.  Driving  pressure  settings  are  usually  20–25  psi  in  adults,  with  a  maximum  of  50  psiInspiration  time  and  respiratory  frequency:  the  major  determinants  of  “auto-PEEP”  (air  trapping).  Inspiration  time  is  usually  set  at  30–40%  and  respiratory  frequency  is  between  50  and  150  bpm.  By  increasing  either  value,  auto-PEEP  is  increased,  which  allows  recruitment  of  alveoli,  optimization  of  V/Q  matching,  and  improvement  in  oxygenation.  Auto-PEEP  may  also  be  beneficial  when  a  “still”  surgical  field  is  desired  because  chest  wall  excursions  are  reducedFiO2:  always  set  at  100%.  It  is  the  oxygen  concentration  at  the  jet  nozzle.  However,  the  actual  FiO2  in  the  alveoli  is  significantly  lower  due  to  the  Venturi  effect  (negative  pressure  around  gas  flow  that  drags  air  from  the  environment  into  the  airway)  and  the  use  of  an  open  systemHumidification:  used  when  prolonged  jet  ventilation  anticipated  in  order  to  avoid  mucus  membrane  damage  or  formation  of  mucus  clot  leading  to  airway  obstructionThe  mechanism  of  gas  exchange  is  unlike  that  in  conventional  ventilation:  CO2  elimination  is  possible  because  of  a  combination  of  bulk  convection,  molecular  diffusion,  and  turbulence  of  convective  flowDue  to  the  lower  peak  and  mean  airway  pressures  in  HFJV,  intrathoracic  pressures  are  decreased  leading  to  increased  venous  return  and  improved  cardiac  function  
SN  - 
PB  - The McGraw-Hill Companies
CY  - New York, NY
Y2  - 2024/04/17
UR  - accessanesthesiology.mhmedical.com/content.aspx?aid=57261073
ER  -