P.L.V.

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P.L.V.
Partial Liquid Ventilation

• Eugene Yevstratov MD
• 2008

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ARDS
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ARDS Stages
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UNDERSTANDING ARDS
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Survival and Mortality
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Treatment Options
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Basic physics related to mechanical ventilation
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Basic physics related to mechanical ventilation
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Basic physics related to mechanical ventilation

• Pressure at point B is equivalent to the alveolar
  pressure and is determined by the volume
  inflating the alveoli divided by the compliance
  of the alveoli plus the baseline pressure (PEEP)
• Pressure at point A (equivalent to airway
  pressure measured by the ventilator) is the sum
  of the product of flow and resistance due to the
  tube and the pressure at point B.
• Flow, volume and pressure are variables while
  resistance and compliance are constants.
• Flow Volume/time
• It follows from the relationships between
  pressure, flow and volume that by setting one of
  pressure, volume or flow and the pattern in which
  it is delivered (which includes the time over
  which it is delivered) the other two become
  constants.
• It also follows that it is not possible to preset
  more than one of these variables as well as time

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Partial liquid ventilation is a complex and
laborintensive procedure requiring a team
approach, including meticulous nursing care to
prevent adverse reactions. For his safety and
comfort during PLV, your patient may receive a
combination of neuromuscular blocking agents,
sedatives, and antianxiety agents. Be sure to
explain to him and his family beforehand what PLV
will involve and answer their questions.
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Perfluorocarbons distribution
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P.L.V

• Improvement in compliance may simply be due to
  recruitment of alveoli but may be also be due to
  a direct effect on surface tension
• Other postulated benefits- barrier against
  infection washes out inflammatory debris

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P.L.V.

• Still an experimental technique
• Lung is partially filled with perfluorocarbon and
  patient is ventilated with conventional apparatus
  
• Perfluorocarbons are simple organic compounds in
  which all the hydrogen atoms have been replaced
  by halogens. There physicochemical properties
  include high density, relatively high viscosity,
  low surface tension and a remarkable ability to
  dissolve both oxygen and carbon dioxide

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High frequency ventilation

• ventilation of lungs at a frequency gt 4 times
  normal rate- Most important difference from
  conventional IPPV is that it requires tidal
  volumes of only 1-3 ml/kg body weight to achieve
  normocarbia- 3 types high frequency positive
  pressure (used in anaesthesia), high frequency
  jet (anaesthesia and ICU) and high frequency
  oscillation

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Advantages

• - Reduced peak and mean airway pressures-
  Improved CVS stability due to above- Decreased
  risk of barotrauma- Allows adequate ventilation
  with a disrupted airway (eg bronchopleural
  fistula)- Permits mechanical ventilation during
  bronchoscopy- Improves operating conditions eg
  in thoracic surgery- Allows ventilation through
  narrow catheters and thus increases access during
  laryngeal and trachael surgery- Reduces sedation
  requirements when used in ITU- Avoidance of
  hypoxia during tracheobronchial toilet

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Disadvantages

• - Specialized equipment required- Dangers of
  high pressure gas flows- Humidification of
  inspired gases difficult- Tidal volumes markedly
  affected by changes in respiratory compliance-
  Monitoring of ventilation parameters difficult-
  Difficult to predict minute ventilation from
  ventilator

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Prone ventilation

• Probable mechanism is that when patient is turned
  prone the ventilation to the dorsal atelectatic
  parts of the lung is improved. However perfusion
  continues to pass preferentially to these regions
  and hence shunt is reduced
• Reduction in thoraco-abdominal compliance thought
  to play an important part in producing beneficial
  effects of prone ventilation
• Most common serious complication of turning prone
  is accidental extubation

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ECMO

• Extracorporeal life support, or extracorporeal
  lung assist

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Eugene Yevstratov MD
eugenefox_at_aol.com