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Tools for protective lung ventilation. The elastic pressure-volume curve and aspiration of dead space

De Robertis, Edoardo LU (2000)
Abstract (Swedish)
Popular Abstract in Swedish

Mekanisk ventilation kan medföra "ventilationsinducerad lungskada" (VILI), som kan öka sjuklighet och dödlighet i samband med akut lungskada (ALI). Flera ventilationssätt har föreslagits för att undvika VILI, men inte slutgiltigt utvärderats. En princip är att öka alveolär ventilation och CO2-elimination genom att minska ventilationen av de skadliga rummet, dead space. Aspiration av gas från dead space (ASPIDS) innebär att CO2-rik gas via en särskild kanal sugs ut från distala delen av trakealtuben under senare delen av utandningen. Samtidigt injiceras färsk gas genom den vanliga inandningsvägen.



För att minska risker med mekanisk ventilation har den elastiska tryckvolymkurvan,... (More)
Popular Abstract in Swedish

Mekanisk ventilation kan medföra "ventilationsinducerad lungskada" (VILI), som kan öka sjuklighet och dödlighet i samband med akut lungskada (ALI). Flera ventilationssätt har föreslagits för att undvika VILI, men inte slutgiltigt utvärderats. En princip är att öka alveolär ventilation och CO2-elimination genom att minska ventilationen av de skadliga rummet, dead space. Aspiration av gas från dead space (ASPIDS) innebär att CO2-rik gas via en särskild kanal sugs ut från distala delen av trakealtuben under senare delen av utandningen. Samtidigt injiceras färsk gas genom den vanliga inandningsvägen.



För att minska risker med mekanisk ventilation har den elastiska tryckvolymkurvan, Pel/V-kurvan, föreslagits som ledtråd. Andetagsvolymen skulle begränsas till det linjära segmentet av denna kurva. Därigenom skulle lungkollaps och övertänjning av lungan undvikas nedom respektive ovan detta segment. Full förståelse för fysiologin bakom kurvans mönster saknas emellertid.



Målet med studierna i denna avhandling var att öka förståelsen avfenomen bakom Pel/V-kurvan, att öka dess potentiella kliniska användbarhet och att utveckla och testa ASPIDS. Genom detta avsågs att utveckla en ny strategi för att unvika VILI. Med en datorstyrd ServoVentilator 900C kunde standardiserade och noggranna Pel/V-kurvor registreras och ett system för ASPIDS realiseras. Med ASPIDS kunde ventilationen av dead space minska så att andetagsvolymen kunde reduceras utan att CO2 anhopades i kroppen. På patienter med ALI kunde det slutexpiratoriska trycket ökas. Kontinuerlig rekrytering av lungor visades börja nedom den lägre inflektionspunkten på Pel/V-kurvan och fortsätter långt ovan den punkten. MultiplaPel/V-kurvor gav viktig information om lungans kollaptendens och kunde ge vägledning vid inställning av respiratorn. Konceptuell fysiologisk och teknisk utveckling beskriven i denna avhandling kan förhoppningsvis bana väg för lungbeskyddande mekanisk ventilation. (Less)
Abstract
Ventilator-induced lung injury (VILI) may contribute to morbidity and mortality of acute lung injury (ALI). Lung protective ventilation (LPV), that reduces VILI, may involve low tidal volume (Vt). Particularly low Vt is possible if dead space ventilation is reduced e.g. by aspiration of dead space gas (ASPIDS). ASPIDS implies that gas rich in CO2 during expiration is aspirated through a separate channel from the tracheal tube and replaced by fresh gas injected in the inspiratory line. The elastic pressure volume (Pel/V) curve of the respiratory system is recommended as a guideline to set the ventilator so as to reduce VILI. The Vt should be confined to the linear segment of the Pel/V curve, to avoid lung collapse below this zone, and... (More)
Ventilator-induced lung injury (VILI) may contribute to morbidity and mortality of acute lung injury (ALI). Lung protective ventilation (LPV), that reduces VILI, may involve low tidal volume (Vt). Particularly low Vt is possible if dead space ventilation is reduced e.g. by aspiration of dead space gas (ASPIDS). ASPIDS implies that gas rich in CO2 during expiration is aspirated through a separate channel from the tracheal tube and replaced by fresh gas injected in the inspiratory line. The elastic pressure volume (Pel/V) curve of the respiratory system is recommended as a guideline to set the ventilator so as to reduce VILI. The Vt should be confined to the linear segment of the Pel/V curve, to avoid lung collapse below this zone, and hyperinflation above it. However, the understanding of physiological phenomena behind the Pel/V curve is limited. The objectives were to increase our comprehension of the Pel/V curve, to enhance its potential clinical usefulness, and to develop and test ASPIDS, in an approach aiming at LPV. A computer controlled Servo Ventilator 900 C allowed accurate recording of the Pel/V curve and control of the ASPIDS system. ASPIDS allowed isocapnic ventilation of pigs and humans with low Vt, and higher PEEP levels in ALI patients. In pigs and humans recruitment was shown to start below the lower inflection point and to continue far above it. Pel/V curves recorded from different PEEP levels allowed evaluation of lung collapse and guidance in setting PEEP. New concepts will hopefully increase the feasibility of LPV. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Prof. Lachmann, Burkhard, Erasmus University, Rotterdam, The Netherlands
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Clinical physics, radiology, tomografi, medicinsk instrumentering, radiologi, Klinisk fysiologi, tomography, medical instrumentation, Respiratory system, Andningsorganen
pages
86 pages
defense location
Föreläsningssal 2, Centralblocket, Universitetssjukhuset i Lund
defense date
2000-05-30 10:15
external identifiers
  • Other:ISRN: LUMEDW/MEFL--1016--SE
language
English
LU publication?
yes
id
bcd690ad-b278-4f3a-97af-e3887b01cfba (old id 19770)
date added to LUP
2007-05-25 15:27:58
date last changed
2016-09-19 08:45:17
@misc{bcd690ad-b278-4f3a-97af-e3887b01cfba,
  abstract     = {Ventilator-induced lung injury (VILI) may contribute to morbidity and mortality of acute lung injury (ALI). Lung protective ventilation (LPV), that reduces VILI, may involve low tidal volume (Vt). Particularly low Vt is possible if dead space ventilation is reduced e.g. by aspiration of dead space gas (ASPIDS). ASPIDS implies that gas rich in CO2 during expiration is aspirated through a separate channel from the tracheal tube and replaced by fresh gas injected in the inspiratory line. The elastic pressure volume (Pel/V) curve of the respiratory system is recommended as a guideline to set the ventilator so as to reduce VILI. The Vt should be confined to the linear segment of the Pel/V curve, to avoid lung collapse below this zone, and hyperinflation above it. However, the understanding of physiological phenomena behind the Pel/V curve is limited. The objectives were to increase our comprehension of the Pel/V curve, to enhance its potential clinical usefulness, and to develop and test ASPIDS, in an approach aiming at LPV. A computer controlled Servo Ventilator 900 C allowed accurate recording of the Pel/V curve and control of the ASPIDS system. ASPIDS allowed isocapnic ventilation of pigs and humans with low Vt, and higher PEEP levels in ALI patients. In pigs and humans recruitment was shown to start below the lower inflection point and to continue far above it. Pel/V curves recorded from different PEEP levels allowed evaluation of lung collapse and guidance in setting PEEP. New concepts will hopefully increase the feasibility of LPV.},
  author       = {De Robertis, Edoardo},
  keyword      = {Clinical physics,radiology,tomografi,medicinsk instrumentering,radiologi,Klinisk fysiologi,tomography,medical instrumentation,Respiratory system,Andningsorganen},
  language     = {eng},
  pages        = {86},
  title        = {Tools for protective lung ventilation. The elastic pressure-volume curve and aspiration of dead space},
  year         = {2000},
}