RT Book, Section
A1 MacIntyre, Neil
A1 Branson, Richard D.
A2 Tobin, Martin J.
SR Print(0)
ID 57066056
T1 Chapter 15. Feedback Enhancements on Conventional Ventilator Breaths
T2 Principles and Practice of Mechanical Ventilation, 3e
YR 2013
FD 2013
PB The McGraw-Hill Companies
PP New York, NY
SN 978-0-07-173626-8
LK accessmedicine.mhmedical.com/content.aspx?aid=57066056
RD 2024/04/19
AB The  first  generation  of  positive-pressure  mechanical  ventilators  were  simple  high-pressure  gas  regulators  on  which  clinicians  could  set  the  circuit  pressure  and  the  breathing  frequency.  In  the  middle  of  the  twentieth  century,  more  sophisticated  devices  appeared  that  allowed  direct  clinician  control  of  flow  and  volume  along  with  breath  timing  and  expiratory  pressure.  As  ventilator  design  improved  and  microprocessors  became  available,  feedback  mechanisms  appeared  that  could  provide  automatic  adjustments  in  these  set  variables  depending  upon  a  variety  of  conditions.1  A  simple  example  was  the  use  of  a  patient-effort  sensor  to  adjust  the  number  of  mechanical  breaths  provided  during  assist-control  modes  or  synchronized  intermittent  mandatory  ventilation.2–4  A  variation  on  this  breath  rate  feedback  mechanism  was  mandatory  (or  minimum)  minute  ventilation,  which  used  minute  ventilation  to  adjust  the  number  of  positive-pressure  breaths  delivered.5  At  the  same  time,  the  development  of  flow  control  valves  that  could  be  adjusted  based  on  a  clinician-selected  airway-pressure  target  appeared.6–9  This  gave  clinicians  the  choice  of  using  either  set  flow-volume-targeted  modes  (volume  assist-control  ventilation;  volume-targeted  synchronized  intermittent  mandatory  ventilation  [volume  SIMV])  or  pressure-targeted  modes  (pressure-targeted  assist-control  ventilation  [PACV];  pressure  support;  pressure  SIMV).  Taken  together,  these  flow-targeted,  volume-targeted,  and  pressure-targeted  strategies  comprise  what  is  commonly  referred  to  today  as  “conventional”  mechanical  ventilation.