[Intensive insulin therapy in critically ill patients--contra].
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Blood Glucose↗
Biomedical subjects
Gernot Marx
Publications and source records attributed to Gernot Marx.
Blood volume measurements using an integrated fiberoptic monitoring system in a porcine septic shock model.
OBJECTIVES: To compare the accuracy of an integrated fiberoptic monitoring system using transpulmonary thermo-dye dilution technique to measure blood volume (BV) with standard method using chromium-51-tagged erythrocytes in septic shock. DESIGN: Prospective blinded animal laboratory study. SETTING: University department of anesthesiology. SUBJECTS: Thirty-five anesthetized and mechanically ventilated pigs (21.4 +/- 2.2 kg) were investigated over a period of 6 hrs. INTERVENTIONS: Septic shock was induced with fecal peritonitis (0.75 g . kg per body weight autologous feces). A central venous catheter was used for injection of the indicator dyes. MEASUREMENTS AND MAIN RESULTS: BV was measured by detecting indocyanine green using a 4-Fr aortic catheter with an integrated fiberoptic and thermistor connected to a computer system for calculation of transpulmonary indicator dilution BV (BVTPID). Cr-tagged erythrocytes were used as standard method of BV measurement (BV-Cr). Hemodynamic treatment scheme was aimed at maintenance of a central venous pressure of 12 mm Hg. Data were analyzed using Bland-Altman analyses. One hundred and five data pairs of simultaneous BV measurements were yielded during hemodynamic stability with a mean BVTPID of 64.2 +/- 17.8 mL . kg. Mean BV-Cr was 83.1 +/- 17.0 mL . kg. Linear regression equation was BVTPID = 0.58 x BV-Cr + 15.8 (r = .56, p < .01). Mean bias was 18.9 mL . kg (95% confidence interval, 15.7-22.1 mL . kg), with limits of agreement of -13.9 to 51.7 mL . kg. CONCLUSIONS: Transpulmonary indicator dilution for blood volume measurement agrees moderately with standard method using Cr-tagged erythrocytes in porcine septic shock.
Animals↗
Attenuation of capillary leakage by hydroxyethyl starch (130/0.42) in a porcine model of septic shock.
OBJECTIVES: Capillary leakage, a frequent complication in septic shock, is characterized by loss of intravasal fluid resulting in generalized edema and hemodynamic instability despite massive fluid therapy. We have shown that administration of an established colloid 200/0.5 hydroxyethyl starch (HES) stabilized plasma volume in a porcine septic shock model. Recently, a new HES with a low molecular weight (130 kD) and lower molar substitution (0.42) has been developed. In this study, we compared effects of HES 130/0.42 and HES 200/0.5 on capillary leakage in porcine septic shock. DESIGN: Prospective randomized, controlled animal study. SETTING: University department of anesthesiology. SUBJECTS: Fourteen pigs (22.9 +/- 2.8 kg). INTERVENTIONS: Anesthetized and mechanically ventilated pigs were observed over 6 hrs. MEASUREMENT AND MAIN RESULTS: Septic shock was induced with fecal peritonitis (0.75 g.kg of body weight autologous feces). Animals were allocated to volume-replacement therapy with either HES 130/0.42 (n = 5) or HES 200/0.5 (n = 5) and compared with nonseptic controls receiving HES 130/0.42 (n = 4). Infusion rate was titrated to maintain a central venous pressure of 12 mm Hg. Albumin escape rate was calculated using iodine 125-labeled albumin. Plasma volume was determined using chromium-51-tagged erythrocytes. Albumin escape rate increased significantly in both groups in comparison to controls (HES 200/0.5, 45% +/- 3; HES 130/0.42, 38% +/- 5), but this increase was significantly smaller with HES 130/0.42. Both HES 200/0.5 (-14%, not significant) and HES 130/0.42 (-1%, not significant) stabilized plasma volume compared with controls. Systemic oxygenation was not significantly altered in either group. CONCLUSIONS: In this porcine septic shock model, HES 130/0.42 attenuated capillary leakage significantly more effectively than HES 200/0.5.
Animals↗
Venous oximetry.
PURPOSE OF REVIEW: Mixed venous and central venous oxygen saturations reflect the balance between oxygen requirement and oxygen delivery, and thus may be used to assess the adequacy of tissue oxygenation. This review discusses recent data on the impact of using venous oximetry by obtaining mixed venous oxygen saturation or central venous oxygen saturation as useful monitoring parameters in critically ill patients. RECENT FINDINGS: Monitoring of changes in the central venous oxygen saturation after major surgery has been shown to be associated with outcome. Furthermore, early goal-directed therapy for patients with severe sepsis or septic shock, which includes treatment goals for mean arterial pressure, central venous pressure, and central venous oxygen saturation, was able to increase survival in these patients. In contrast, pulmonary artery catheter usage does not affect outcome in critically ill patients. SUMMARY: Early goal-directed therapy should be implemented in the initial resuscitation of septic patients. Central venous saturation may have prognostic significance following major surgery. Further evaluation of peri-operative trends in central venous saturation is required. Measurement of central venous oxygen saturation can easily be applied in intensive care unit patients and offers a useful, indirect indicator for the adequacy of tissue oxygenation.
Blood Gas Analysis↗
Correlation of oxygen delivery with central venous oxygen saturation, mean arterial pressure and heart rate in piglets.
BACKGROUND: Accurate assessment and monitoring of the cardiocirculatory function is essential during major pediatric and pediatric cardiac surgery. Invasive monitoring of cardiac output and oxygen delivery (DO(2)) is expensive and sometimes associated with adverse events. Measurement of central venous oxygen saturation (ScvO(2)) is less invasive and may reflect the DO(2). Therefore, we investigated the correlation of ScvO(2) with cardiac index (CI) and DO(2) and in comparison the more common monitored parameters heart rate (HR) and mean arterial pressure (MAP) with DO(2) in an animal experimental setting. METHODS: In five fasted, anesthetized and mechanically ventilated piglets CI (transpulmonary thermodilution), venous and arterial blood gases, HR and MAP was measured during normal conditions, volume loading, inotropic support, and exsanguination. RESULTS: In the five piglets 168 measurements could be performed. In a wide hemodynamic range (CI 22-335 ml x kg(-1) min(-1)) we found significant correlations of ScvO(2) with DO(2)) (r(2) = 0.91, P < 0.0001) and CI (r(2) = 0.88, P < 0.0001) and also between DO(2) and MAP (r = 0.86, P < 0.0001) and HR (r = 0.19, P < 0.05). CONCLUSIONS: ScvO(2) is a better parameter for indirect estimation of DO(2) than MAP and heart rate. Measurement of ScvO(2) is simple and does not necessitate additional invasive techniques. In the clinical setting ScvO(2) should be used in combination with other standard vital parameters, i.e. MAP, central venous pressure, lactate, base excess, and urine output.
Animals↗
Continuous monitoring of central venous oxygen saturation in neonates and small infants: in vitro evaluation of two different oximetry catheters.
BACKGROUND: Accurate assessment and monitoring of the cardiocirculatory function are essential during major pediatric and pediatric cardiac surgery. Monitoring of the central venous oxygen saturation (ScvO(2)) may be a better indicator of tissue oxygenation and derangement of cellular oxygen utilization than the more commonly used vital parameters. Therefore, we compared oxygen saturation measurements with thin fiberoptic oximetry catheters and standard blood gas oximetry in an in vitro setting. METHODS: Two different size continuous fiberoptic oximetry catheters (2-4-F) were inserted in an extracorporeal circuit filled with human red blood cells in normal saline (haematocrit 30%, flow 600 ml.min(-1)). The results of fiberoptic oximetry were then compared with standard blood gas oximetry for a wide range of different oxygen saturations using linear regression. RESULTS: The oxygen saturations found ranged from 9% to 100%. The results of the two different fiberoptic oximetry catheters correlated significantly (r = 0.99, P < 0.0001) with standard blood gas oximetry. CONCLUSION: The results of fiberoptic oximetry are nearly identical with standard blood gas oximetry for a wide range of different oxygen saturations. Thin oximetry catheters can be inserted percutaneously even in neonates and small infants. The continuous monitoring of ScvO(2) may be beneficial, especially in patients who are in danger of developing low cardiac output or sudden cardiovascular collapse.
Blood Gas Monitoring, Transcutaneous↗
Hemodynamic changes during acute elevation of intra-abdominal pressure in rabbits.
BACKGROUND: The intra-abdominal pressure (IAP) may be increased during pneumoperitoneum for minimally invasive surgery, after high tension repairs of congenital abdominal wall defects, major abdominal surgery, liver transplantation, abdominal trauma, peritonitis or ileus. The aim of this study was to investigate hemodynamic changes during elevation of IAP using an experimental setting, which mirrors anatomical and physiological conditions of neonates and small infants as closely as possible. METHODS: In five fasted, anesthetized, mechanically ventilated and multicatheterized New Zealand rabbits, the IAP was gradually increased by intra-abdominal infusion of normal saline (total volume 1000 ml). At baseline and after each infusion of 100 ml normal saline cardiac output (CO, transcardiopulmonary thermodilution), pressure in the superior (SVCP) and inferior vena cava (IVCP), mean arterial pressure (MAP), peak airway pressure (PAP) and IAP was recorded. RESULTS: During the study, IAP, SVCP and IVCP increased significantly. IVCP was significantly higher than SVCP from timepoint 200 ml to study end. After abdominal decompression IAP, SVCP and IVCP decreased to baseline levels. Changes in MAP were not significant. CO increased significantly from baseline to timepoint 200 ml (peak value), remained nearly constant until timepoint 800 ml and decreased thereafter until the abdominal infusion ceased. After abdominal decompression CO returned to baseline level. SVCP, IVCP and PAP correlated significantly with IAP (SVCP, r = 0.73; IVCP, r = 0.97; PAP, r = 0.94; P < 0.0001). CONCLUSIONS: The hemodynamic changes caused by increased IAP cannot be recognized by routine monitoring of arterial blood pressure and transcutaneous oxygen saturation. The increase in central venous pressure may be misinterpreted as an elevation of cardiac preload. One major effect of a prolonged increase in IAP is a decreased CO.
Animals↗
Activated protein C induces the release of microparticle-associated endothelial protein C receptor.
Activated protein C (APC) treatment is now used for patients with severe sepsis. We investigated its effect in vitro on primary, physiologically relevant cells and demonstrate a novel mechanism of endothelial protein C receptor (EPCR) release that is not inhibited by metalloproteinase inhibitors. Exposure of human umbilical vein endothelial cells or monocytes to APC (6.25-100 nM) results in the release of EPCR-containing microparticles, as demonstrated by confocal microscopy and characterized through flow cytometry, enzyme-linked immunosorbent assay quantitation of isolated microparticles, and Western blotting. The phenomenon is time- and concentration-dependent and requires the APC active site, EPCR, and protease activated receptor 1 (PAR1) on endothelial cells. Neither protein C nor boiled or D-Phe-Pro-Arg-chloromethylketone-blocked APC can induce microparticle formation and antibody blockade of EPCR or PAR1 cleavage and activation abrogates this APC action. Coincubation with hirudin does not alter the APC effect. The released microparticle bound is full-length EPCR (49 kDa) and APC retains factor V-inactivating activity. Although tumor necrosis factor-alpha (10 ng/mL) can also induce microparticle-associated EPCR release to a similar extent as APC (100 nM), it is only APC-induced microparticles that contain bound APC. This novel observation could provide new insights into the consequences of APC therapy in the septic patient.
Anticoagulants↗
Resuscitation from septic shock with capillary leakage: hydroxyethyl starch (130 kd), but not Ringer's solution maintains plasma volume and systemic oxygenation.
There is evidence suggesting that early fluid resuscitation is beneficial in the treatment of septic shock. The question as to which solution should be used remains controversial. Using a porcine septic shock model, we tested the effects of a new synthetic colloid hydroxyethyl starch (HES 130 kD) and a crystalloid regimen with Ringer's solution (RS) on plasma volume (PV) maintenance as well as on systemic and regional hemodynamics. Fourteen anaesthetized mechanically ventilated pigs received 0.75 g kg body weight of feces into the abdominal cavity to induce sepsis. They were randomly allocated to receive 6% HES 130 kD (n = 5) or RS (n = 5) and were compared with nonseptic controls receiving 6% HES 130 kD (n = 4). The infusion rate was titrated to maintain a central venous pressure of 12 mmHg. PV was determined by chromium-51-tagged erythrocytes and hematocrit. Albumin escape rate (AER) was calculated using iodine-125-labeled albumin. Arterio-intramucosal pCO2 gap, systemic hemodynamics, and oxygenation were obtained before and 6 h after induction of sepsis. AER increased in the HES (+38%) and RS groups (+38%) compared with control. PV was reduced in the RS group (-39%), but was maintained in the HES group (-1%). After 6 h of sepsis, HES 130 kD-treated animals had a significantly higher cardiac output (166 +/- 28 mL min kg vs. 90 +/- 18 mL min kg, P < 0.05), and a significantly higher mixed-venous oxygen saturation (65% +/- 8% vs. 40% +/- 14%, P < 0.05) than RS animals. In this porcine septic shock model with concomitant capillary leakage syndrome, resuscitation with HES 130 kD but not RS could maintain PV and preserve systemic hemodynamics and oxygenation.
Animals↗