Alveolar dead space, alveolar shunt, and transpulmonary pressure

Workman, Jacob; Penman, Robert W.; Bromberger-Barnea, B.; Permutt, Solbert; Riley, Richard L.

doi:10.1152/jappl.1965.20.5.816

Cited by 16 publications

(11 citation statements)

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“…[070 P(a-ET)co z = (Paco 1 -PETco 1 ) I Paco 2 ] as a measure of the baseline ratio of alveolar dead space relative to total alveolar ventilation (Vnalv/Vralv) (16)(17)(18). The effective tidal volume (Vreff) inspired by the patient.s was obtained by correcting the iVT for compressible volume and adding the volume delivered by the catheter during the inspiratory time (TI) (7,12):…”

Section: Calculation Of Parameters and Data Analysismentioning

confidence: 99%

“…The %P(a-ET)c02 has been shown to be a convenient and simple method of assessing the magnitude of Vnalv relative to total VA (16)(17)(18)22). In patients with ARDS, the ratio of unperfused but ventilated alveoli (i.e., Vnalv) is increased as a result of pulmonary vasoconstriction and extensive microvascular obliteration, which may dilute the Pe0 2 residing in the proximal Vnanat such that TOI can flush less CO 2 during expiration (18,23).…”

Section: Effeas Of Ventilatory Mode and Catheter Flow On Measured Varmentioning

confidence: 99%

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Efficacy of tracheal gas insufflation in acute respiratory distress syndrome with permissive hypercapnia.

Kuo

Wu²,

Yu³

et al. 1996

Am J Respir Crit Care Med

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This study was conducted to assess the CO2-elimination efficiency of tracheal gas insufflation (TGI) in 20 patients with acute respiratory distress syndrome and to compare its efficacy during volume-controlled (VCV) and pressure-controlled ventilation (PCV). TGI was initially applied as an adjunct to VCV, with continuous flows (Vcath) of 4 and 6 L/min delivered through a catheter positioned 2 cm above the carina. Total effective tidal volume (VTeff) was held constant. The percent reductions in PaCO2 (% delta PaCO2) were 13.3 +/- 2.1 and 16.7 +/- 2.7% at Vcath 4 and 6 L/min, respectively, which correlated well with the percent reduction in the end-tidal PCO2 from baseline (% delta PETCO2) (r = 0.75, p < 0.001). An inverse relationship (r = -0.65, p < 0.001 and r = -0.59, p < 0.01 at Vcath 4 and 6 L/min, respectively) was found between the % delta PaCO2 and the baseline ratio of artery to PETCO2 difference to PaCO2, which was determined as the fraction of alveolar dead space (VDalv) relative to total alveolar ventilation. Twelve patients were subsequently switched to PCV combined with Vcath 6 L/min, which provided a % delta PaCO2 of 16.1 +/- 3.0% (p = NS versus 17.1 +/- 2.6% during VCV). These data suggest that in patients with ARDS the change in PETCO2 may be helpful in predicting the decrement in PaCO2 during TGI, and the existence of a high VDalv tends to limit its effectiveness. Further, the efficacy of TGI with VCV is equivalent to that with PCV.

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Section: Calculation Of Parameters and Data Analysismentioning

confidence: 99%

Section: Effeas Of Ventilatory Mode and Catheter Flow On Measured Varmentioning

confidence: 99%

Efficacy of tracheal gas insufflation in acute respiratory distress syndrome with permissive hypercapnia.

Kuo

Wu²,

Yu³

et al. 1996

Am J Respir Crit Care Med

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“…Examining gas exchange in open-chested dogs in terms of a three-com partmented model (dead space, ventilated-perfused lung, and shunt), Workman et al (97) find that the shunt compartment becomes smaller when transpulmonary pressure is increased, but the dead space compart ment is unaffected. Penman & Howard (98) examined gas exchange of normal subjects and patients with chronic bronchitis in terms of a three compartmental lung.…”

Section: Distribution Of Ventilation and Blood Flowmentioning

confidence: 99%

Respiration

Bernstein¹

1967

Annu. Rev. Physiol.

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Limitation of space dictates that I omit several topics from this review; among these are pulmonary pathophysiology and pulmonary function testing; cell respiration; pharmacology of respiration; adaptation to long term environmental changes; and comparative physiology, either of inter species variation or of variation within the individual related to age and stage of development. These topics are included in a longer bibliography. 2 BOOKS, REVIEWS, CONFERENCESRespiration physiologists now have their own, eponymously titled jour nal (l).It has been a good year for books: Aviado's account of the pulmonary circulation (2) , that must for a long time be the definitive work in this field; Keilin's History of Cell Respiration and Cytochrome (3), completed for the press by his daughter after his death; Volume II of Section 3 (Res piration) of the American Physiological Society's Handbook of Physiology (4); Farhi's literarily and s�ientifically admirable translation into English of Dejour's chapter in Volume III of the French textbook Physiologie (C.Kayser, Ed.), now published as the book Respiration (5) ; a collection of re views (6) of recent progress in their fields, by eight active research work ers; an account of the principles, practice, and interpretation of cl inical pulmonary function tests (7); a simple exposition and discussion of the concept of inhomogeneity of distribution of ventilation and blood flow (8); a somewhat sketchy account of the comparative anatomy, histology, and physiology of respiration throughout the animal kingdom (9) ; and a gener

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“…Por meio da capnografia volumétrica, é possível calcular a concentração média de CO 2 no gás expirado (volume de CO 2 expirado dividido pelo volume expirado). A concentração média de CO 2 no gás expirado (P ET CO 2 ) é utilizada para calcular o espaço morto, a partir da equação de Bohr-Enghoff: (PACO 2 -P ET CO 2 )/PACO 2 , onde PACO 2 é a pressão parcial de CO 2 alveolar 12,[14][15][16] . A importância da curva é identificar a porção de volume corrente que corresponde à exalação de CO 2 da via aérea proximal 16 .…”

Section: Introductionunclassified

Influência da insuflação de gás traqueal sobre a capnografia de pacientes anestesiados

Ortiz¹,

Muneshika²,

Martins³

2008

Rev. Bras. Anestesiol.

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Rev Bras AnestesiolARTIGO CIENTÍFICO 2008; 58: 5: 440-446 SCIENTIFIC ARTICLE RESUMO Ortiz AC, Muneshika M, Martins FANC -Influência da Insuflação de Gás Traqueal sobre a Capnografia de Pacientes Anestesiados. JUSTIFICATIVA E OBJETIVOS:A insuflação de gás traqueal (TGI -Tracheal Gas Insufflation) é uma técnica que consiste em injetar gás na traquéia (geralmente oxigênio). É usada em pacientes portadores de síndrome da angústia respiratória do adulto para reduzir a capnometria. Em Anestesiologia, a redução da capnometria pode ser útil, mas não existem estudos sobre a redução da capnometria com o uso da TGI. O presente estudo avaliou as alterações proporcionadas pela TGI sobre a capnografia em pacientes anestesiados. MÉTODO:Foram avaliados prospectivamente 11 pacientes, 18 a 60 anos, ASA I ou II, não-pneumopatas. Após a intubação traqueal foi inserido cateter para TGI a 2 ou 3 cm da carina. Os pacientes foram submetidos à ventilação controlada a volume. Registrou-se a curva de capnografia volumétrica durante 20 minutos e colheuse amostra sangüínea para medir PaCO 2 . Após 20 minutos de TGI registrou-se a curva de capnografia e foi colhida nova amostra sangüínea para medir PaCO 2 . Avaliou-se pressão parcial de CO 2 no fim da expiração (P ET CO 2 ) e PaCO 2 , antes e após TGI. Observouse curva de capnografia, antes e durante TGI. RESULTADOS:A PaCO 2 e P ET CO 2 sem TGI foram, respectivamente (média ± desvio-padrão): 33,48 ± 6,81 e 36,91 ± 6,54 mmHg e, após TGI, 33,85 ± 8,31 e 36,55 ± 7,93 mmHg, não havendo diferença estatística entre os valores antes e após TGI, tanto para a PaCO 2 quanto para a P ET CO 2 (p = 0,65 e 0,82). A curva de capnografia apresentou alterações na fase de expiração do ar alveolar. CONCLUSÕES:A aplicação da TGI não resultou em diminuição da PaCO 2 e nem na P ET CO 2 , porém alterou a morfologia da curva de capnografia.Unitermos: ANESTESIA, Geral; MONITORIZAÇÃO, CO 2 : capnografia; VENTILAÇÃO: insuflação de gás traqueal. SUMMARYOrtiz AC, Muneshika M, Martins FANC -Influence of Tracheal Gas Insufflation during Capnography in Anesthetized Patients. BACKGROUND AND OBJECTIVES:Tracheal gas insufflation (TGI) consists in injecting gas in the trachea (usually oxygen). It is used in patients with acute respiratory distress syndrome (ARDS) to reduce capnometry. In Anesthesiology, the reduction in capnometry can be useful, but there are no studies on the reduction in capnometry using TGI. The objective of this study was to evaluate the changes caused by TGI on capnometry in anesthetized patients. METHODS:Eleven patients, ages 18 to 60 years, ASA I or II, without lung diseases were evaluated prospectively. After tracheal intubation, a TGI catheter was inserted 2 to 3 cm from the carina. Patients underwent volume-controlled ventilation. The volumetric capnography curve was recorded during 20 minutes and blood was drawn to determine the PaCO 2 . Twenty minutes after TGI was instituted, the capnograph curve was recorded and blood was drawn once more to measure PaCO 2 . The end-tidal partial pressure of CO...

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Alveolar dead space, alveolar shunt, and transpulmonary pressure

Cited by 16 publications

References 0 publications

Efficacy of tracheal gas insufflation in acute respiratory distress syndrome with permissive hypercapnia.

Efficacy of tracheal gas insufflation in acute respiratory distress syndrome with permissive hypercapnia.

Respiration

Influência da insuflação de gás traqueal sobre a capnografia de pacientes anestesiados

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