GASTRIC INTRAMURAL pH AS INDICATOR OF EARLY ALLOGRAFT VIABILITY IN ORTHOTOPIC LIVER TRANSPLANTATION

Frenette, Luc; Doblar, Dennis D.; SINGER, DAN; Cox, Jerry; RONDEROS, JAIME; POPLAWSKI, STEVE; RANJAN, DINESH

doi:10.1097/00007890-199408150-00006

Cited by 9 publications

(12 citation statements)

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“…Perioperative changes in haemodynamic and metabolic variables and in tissue oxygenation are well established during orthotopic liver transplantation (OLT) [1,2]. However, little is known about regional perfusion and oxygenation, particularly of the splanchnic organs, although intestinal hypoxia may be a source of postoperative morbidity and graft dysfunction [3][4][5]. In patients with liver failure secondary to cirrhosis and presenting with a hyperdynamic circulatory state, impaired tissue oxygenation has been observed during operation, although global oxygen delivery and perfusion pressure were adequately maintained [2].…”

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confidence: 99%

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Perioperative mucosal pH and splanchnic endotoxin concentration in orthotopic liver transplantation

Welte

Pichler

Groh

et al. 1996

British Journal of Anaesthesia

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Although impairment of splanchnic perfusion may induce mucosal hypoxia and endotoxaemia during orthotopic liver transplantation (OLT), little is known about the changes in mucosal oxygenation during and after the procedure. To study the effects of liver surgery itself on mucosal pH (pHi) and the response of pHi to acute changes in portal flow, we measured gastric pHi during six liver resections using tonometry: in two patients, after clamping of the hepatoduodenal ligament, pHi decreased within 30 min and recovered promptly after reperfusion. We then investigated gastric and sigmoid pHi (pHig, pHis) during the perioperative phase in 18 OLT. Median pHi values were low before surgery (pHig 7.28 (first/third quartiles 7.22/7.34); pHis 7.27 (7.12/7.36)). Although global oxygen delivery and haemodynamic variables remained constant and veno-venous bypass (VVB) was used to maintain portal flow, pHi declined during the anhepatic phase (pHig 7.19 (7.13/7.23), P < 0.01; pHis 7.13 (7.06/7.24), P < 0.05). After reperfusion of the graft, pHi recovered and did not differ from baseline values by the end of OLT. After operation pHig increased further, reaching the highest values 30 h after ICU admission (7.34 (7.26/7.38)). In the intraoperative period, no significant endotoxaemia was observed either in portal or systemic blood. The maximum reduction in pHi was related neither to the duration of VVB and OLT nor to the number of red cell units transfused. pHi after reperfusion did not correlate with graft viability or dysfunction of the lung or kidney. We conclude that pHi indicates mucosal ischaemia during OLT which is not necessarily associated with endotoxaemia, and intraoperative pHi monitoring does not appear to be a valuable predictor of postoperative graft failure and organ dysfunction.

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“…Accepted for publication: July 30, 1995. an indicator of intestinal ischaemia after aortic surgery [16] and cardiopulmonary bypass [17], and a prognostic factor in critically ill patients [18,19]. More recently, gastric pHi measured 30 min after graft reperfusion has been reported to be an independent indicator of early graft viability in OLT [5].…”

mentioning

confidence: 99%

Perioperative mucosal pH and splanchnic endotoxin concentration in orthotopic liver transplantation

Welte

Pichler

Groh

et al. 1996

British Journal of Anaesthesia

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“…Decreased pHi was also associated with longer ICU stay postop eratively. In a similar study by Frenette et al, 22 25 pa tients with pHi greater than 7.30 during transplant surgery showed good graft function 30 after reperfusion. Ten other patients who had pHi below 7.30, however, demonstrated greater blood product re quirements.…”

Section: Gastric Phi To Predict Morbiditymentioning

confidence: 74%

Gastrointestinal Tonometry: Basic Principles and Recent Advances in Monitoring Regional CO₂Metabolism

Taylor¹,

Gutiérrez²

1999

Semin Respir Crit Care Med

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In the quest to improve outcome in critically ill patients, clinicians have embraced many monitoring modalities in the hope that the sheer quantity of data would assist in the detection and treatment of pathophysiological derangements. Gastrointestinal tonometry has been used increasingly in both the basic science laboratory and the critical care unit, as demonstrated by its mention in more than 800 publications in the medical literature. Tonometric determination of regional PCO 2 is becoming more and more available for clinical use in the intensive care unit (ICU) setting. As reflected by its reluctant acceptance in some circles, however, questions remain surrounding the optimal use of gastrointestinal tonometry and its applications in clinical medicine. This review discusses the physiological basis for using tonometry, as well as many of the studies supporting its role as a monitor of perfusion and local oxidative metabolism. WHAT TONOMETRY MEASURESGastrointestinal tonometry is a relatively nonin vasive technique to assess mucosal PCO 2 as the par tial pressure of CO 2 in a fluid-filled balloon equili brates with the PCO 2 of mucosal interstitial fluid. 1 -3 By detecting fluctuations in tissue CO 2 , tonometry permits monitoring of the adequacy of organ-spe cific cellular energy balance. CO 2 is generated by combustion of O 2 at a rate determined by cellular respiration. Excess production of CO 2 occurs during hypoxia as hydrogen ions (H + ) produced by anaero bic metabolism are buffered by tissue bicarbonate.Under condition of aerobic metabolism, the production of CO 2 by all tissues is directly related to the rate of O 2 consumption. The ratio of CO 2 pro duction to O 2 consumption, known as the respira tory quotient, depends on the substrate used by the mitochondria, with glucose metabolism generating more CO 2 than fat. Production of CO 2 increases sharply under conditions of hypoxia, when anaerobically generated adenosine triphosphate (ATP) un dergoes hydrolysis to result in the cellular accumula tion of H + . Excess tissue CO 2 is subsequently pro duced by the buffering action of bicarbonate on in tracellular H + :This biochemical phenomenon has important clinical relevance because detection of changes in tissue CO 2 concentration may assist the critical care clinician in assessment of cellular energy balance during hypoxia. As a result, tonometric measure ment of intestinal or gastric mucosal PCO 2 provides important metabolic information by relatively non invasive means.The gut mucosa is highly susceptible to dimin ished tissue perfusion and oxygenation. This vulner ability of the gastrointestinal tract to hypoxia is probably related to its unique microvascular ar rangement of arterioles running parallel to venules in a pattern of countercurrent microcirculation. As a result, O 2 can diffuse from arterioles to adjacent venules while CO 2 diffuses from the venous to the

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“…Vários métodos têm sido utilizados com a finalidade de diagnosticar precocemente a isquemia mesentérica e de certa forma, melhorar o prognóstico destes pacientes, incluindo parâmetros laboratoriais, ultra-sonografia, tomografia computadorizada, endoscopia, angiografia, oximetria endoluminal, laser-Doppler entre outros (17,29) . Recentemente, a tonometria, mensurando o CO 2 da mucosa do trato digestivo, tem sido utilizada para a avaliação da perfusão no território esplâncnico em diversas situações clínicas, incluindo sépsis, pós-operatório de transplante hepático e cirurgias cardíacas, entre outros (12,15,19,24,26,32,33,36) . Além disso, a tonometria permite o cálculo do pH intramucoso, que tem sido utilizado não só como marcador de mortalidade em pacientes críticos, mas também como RESUMO -Racional -Apesar dos recentes avanços nos métodos de imagem e no cuidado dos doentes críticos, a taxa de mortalidade do abdome agudo vascular nas últimas duas décadas continua praticamente inalterada.…”

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Avaliação inicial dos gradientes sistêmicos e regionais da pCO2 como marcadores de hipoperfusão mesentérica

Cruz

Correia

Poli-de-Figueiredo

et al. 2006

Arq. Gastroenterol.

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INTRODUÇÃOApesar dos recentes avanços nos métodos de imagem e no cuidado dos doentes críticos, a taxa de mortalidade do abdome agudo vascular nas últimas duas décadas continua praticamente inalterada (23,37,39) . Vários são os fatores relacionados à baixa sobrevida (~7% a 40%) dos pacientes com isquemia mesentérica. Inicialmente, a doença vascular mesentérica acomete geralmente pacientes idosos com várias doenças associadas, dificultando, desta forma, o controle metabólico e infeccioso no pós-operatório. Além disso, o quadro clínico e o exame físico nas fases iniciais da doença são inespecíficos, dificultando o diagnóstico precoce mesmo para o mais experiente dos cirurgiões (17,29) .Vários métodos têm sido utilizados com a finalidade de diagnosticar precocemente a isquemia mesentérica e de certa forma, melhorar o prognóstico destes pacientes, incluindo parâmetros laboratoriais, ultra-sonografia, tomografia computadorizada, endoscopia, angiografia, oximetria endoluminal, laser-Doppler entre outros (17,29) .Recentemente, a tonometria, mensurando o CO 2 da mucosa do trato digestivo, tem sido utilizada para a avaliação da perfusão no território esplâncnico em diversas situações clínicas, incluindo sépsis, pós-operatório de transplante hepático e cirurgias cardíacas, entre outros (12,15,19,24,26,32,33,36) . Além disso, a tonometria permite o cálculo do pH intramucoso, que tem sido utilizado não só como marcador de mortalidade em pacientes críticos, mas também como RESUMO -Racional -Apesar dos recentes avanços nos métodos de imagem e no cuidado dos doentes críticos, a taxa de mortalidade do abdome agudo vascular nas últimas duas décadas continua praticamente inalterada. Objetivos -Avaliar as alterações imediatas dos gradientes regionais da pCO 2 induzidas pela isquemia e reperfusão mesentérica. Determinar se outros marcadores sistêmicos de hipoperfusão esplâncnica são capazes de detectar precocemente as alterações circulatórias ocorridas na mucosa intestinal após oclusão da artéria mesentérica superior. Métodos -Foram utilizados sete cães machos sem raça definida (20,6 ± 1,1 kg), submetidos a oclusão da artéria mesentérica superior por 45 minutos, sendo os animais observados por período adicional de 2 horas após a reperfusão. Variáveis hemodinâmicas sistêmicas foram avaliadas por meio de cateter arterial e Swan-Ganz. A perfusão do sistema digestório foi avaliada pela medida do fluxo sangüíneo da veia mesentérica superior e da serosa jejunal (fluxômetro ultra-sônico). Oferta, taxa de extração e consumo intestinal de oxigênio (DO 2 intest, TEO 2 intest e VO 2 intest, respectivamente), pH intramucoso (tonometria a gás) e os gradientes veia mesentérica-arterial e mucosa-arterial da pCO 2 (D vm-a pCO 2 e D t-a pCO 2 , respectivamente), foram calculados. Resultados -A oclusão da artéria mesentérica superior não esteve associada a alterações hemodinâmicas sistêmicas, mas pôde-se observar aumento significativo do D vm-a pCO 2 (1,7 ± 0,5 para 5,7 ± 1,8 mm Hg) e do D t-a pCO 2 (8,2 ± 4,8 para 48,7 ± 4,6 mm Hg). Na fase de reper...

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GASTRIC INTRAMURAL pH AS INDICATOR OF EARLY ALLOGRAFT VIABILITY IN ORTHOTOPIC LIVER TRANSPLANTATION

Cited by 9 publications

References 0 publications

Perioperative mucosal pH and splanchnic endotoxin concentration in orthotopic liver transplantation

Perioperative mucosal pH and splanchnic endotoxin concentration in orthotopic liver transplantation

Gastrointestinal Tonometry: Basic Principles and Recent Advances in Monitoring Regional CO₂Metabolism

Avaliação inicial dos gradientes sistêmicos e regionais da pCO2 como marcadores de hipoperfusão mesentérica

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GASTRIC INTRAMURAL pH AS INDICATOR OF EARLY ALLOGRAFT VIABILITY IN ORTHOTOPIC LIVER TRANSPLANTATION

Cited by 9 publications

References 0 publications

Perioperative mucosal pH and splanchnic endotoxin concentration in orthotopic liver transplantation

Perioperative mucosal pH and splanchnic endotoxin concentration in orthotopic liver transplantation

Gastrointestinal Tonometry: Basic Principles and Recent Advances in Monitoring Regional CO2Metabolism

Avaliação inicial dos gradientes sistêmicos e regionais da pCO2 como marcadores de hipoperfusão mesentérica

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Product

Resources

About

Gastrointestinal Tonometry: Basic Principles and Recent Advances in Monitoring Regional CO₂Metabolism