Gastrointestinal Impedance Spectroscopy to Detect Hypoperfusion During Hemorrhage. Issue 2 (August 2017)

• Record Type: Journal Article
• Authors: Bloch, Andreas; Kohler, Andreas; Posthaus, Horst; Berger, David; Santos, Laura; Jakob, Stephan; Takala, Jukka; Haenggi, Matthias
• Is Part Of: Shock. Volume 48:Issue 2(2017)
• Publication Date: 2017-08
• Subjects: Gastrointestinal perfusion -- hemorrhagic shock -- impedance spectroscopy -- tissue impedance -- Ω -- tissue impedance -- ANOVA -- analysis of variance -- CVP -- central venous pressure -- ECG -- electrocardiogram -- IQR -- interquartile range -- LDF -- laser Doppler flowmetry -- MAP -- mean arterial blood pressure -- mPAP -- mean pulmonary artery pressure -- PAOP -- pulmonary artery occlusion pressure -- PEEP -- positive end-expiratory pressure -- QSMA -- superior mesenteric artery blood flow -- Qtot -- cardiac output -- RH -- central resistance at high frequencies -- RL -- central resistance at low frequencies -- SvO2 -- mixed venous saturation -- XH -- central reactance at high frequencies -- XL -- central reactance at low frequencies; Shock -- Periodicals; Shock -- Periodicals; Choc (Pathologie) -- Périodiques; Shock; Periodicals; 616.0475
• DOI: 10.1097/SHK.0000000000000824
• Languages: English
• ISSNs: 1073-2322

Abstract

ABSTRACT: Background: Changes in tissue impedance (Ω ) have been proposed as early signs of impaired tissue perfusion. We hypothesized that hemorrhage may induce early changes in alimentary tract tissue impedance and that these can be detected by impedance spectroscopy. We evaluated impedance spectroscopy in an acute hemorrhage model in pigs. Methods: Twenty anesthetized pigs were randomized to stepwise hemorrhage to mean arterial blood pressure (MAP) targets of 60 mm Hg, 50 mm Hg, 45 mm Hg, and 40 mm Hg, followed by retransfusion in two steps, or control (n = 10 each). In the end, 500 mL of enteral nutrition was administered in both groups.Ω in four sites (sublingually, esophagus, stomach, proximal jejunum) and cardiac output (Qtot thermodilution), superior mesenteric artery blood flow (QSMA ; Doppler ultrasound), and jejunal mucosal blood flow (LDF; laser Doppler) were measured. Findings: The bleeding (total volume 838 ± 185 mL; mean ± SD) resulted in progressive hypotension (actual MAP 65 ± 3 mm Hg, 59 ± 4 mm Hg, 55 ± 5 mm Hg, and 46 ± 6 mm Hg) and decrease in Qtot, QSMA, and mucosal LDF. Bleeding did not changeΩ in any of the monitoring sites. Retransfusion restored the blood flows to at least baseline levels, again without change inΩ . Enteral nutrition did not alterΩ or any of the blood flows. Five animals (three in the hemorrhage group, two in the control group) had histologically proven acute gastric focal necrosis at the site of It transducer. Conclusions: Gastrointestinal impedance spectroscopy does not detect early changes in tissue perfusion during progressive hemorrhage or retransfusion.Ω spectroscopy is unlikely to provide any additional information of hypovolemia-induced early changes in gastrointestinal perfusion. Abstract : Supplemental Digital Content is available in the text