Ischemic injury of the upper gastrointestinal tract after out-of-hospital cardiac arrest: a prospective, multicenter study.

BACKGROUND: The consequences of cardiac arrest (CA) on the gastro-intestinal tract are poorly understood. We measured the incidence of ischemic injury in the upper gastro-intestinal tract after Out-of-hospital CA (OHCA) and determined the risk factors for and consequences of gastrointestinal ischemic injury according to its severity. METHODS: Prospective, non-controlled, multicenter study in nine ICUs in France and Belgium conducted from November 1, 2014 to November 30, 2018. Included patients underwent an esophago-gastro-duodenoscopy 2 to 4 d after OHCA if still intubated and the presence of ischemic lesions of the upper gastro-intestinal tract was determined by a gastroenterologist. Lesions were a priori defined as severe if there was ulceration or necrosis and moderate if there was mucosal edema or erythema. We compared clinical and cardiac arrest characteristics of three groups of patients (no, moderate, and severe lesions) and identified variables associated with gastrointestinal ischemic injury using multivariate regression analysis. We also compared the outcomes (organ failure during ICU stay and neurological status at hospital discharge) of the three groups of patients. RESULTS: Among the 214 patients included in the analysis, 121 (57%, 95% CI 50-63%) had an upper gastrointestinal ischemic lesion, most frequently on the fundus. Ischemic lesions were severe in 55/121 (45%) patients. In multivariate regression, higher adrenaline dose during cardiopulmonary resuscitation (OR 1.25 per mg (1.08-1.46)) was independently associated with increased odds of severe upper gastrointestinal ischemic lesions; previous proton pump inhibitor use (OR 0.40 (0.14-1.00)) and serum bicarbonate on day 1 (OR 0.89 (0.81-0.97)) were associated with lower odds of ischemic lesions. Patients with severe lesions had a higher SOFA score during the ICU stay and worse neurological outcome at hospital discharge. CONCLUSIONS: More than half of the patients successfully resuscitated from OHCA had upper gastrointestinal tract ischemic injury. Presence of ischemic lesions was independently associated with the amount of adrenaline used during resuscitation. Patients with severe lesions had higher organ failure scores during the ICU stay and a worse prognosis. Clinical Trial Registration NCT02349074 .

[Pseudo-hyperkalemia and hyperleukocytosis]. / Pseudo-hyperkaliémie et hyperleucocytose.

A pseudo-hyperkalemia may occur with hyperleukocytosis. It is important to recognize it early to avoid unnecessary or even dangerous treatment inducing hypokalemia. The pseudohyperkalemia is due to cell fragility coupled to mechanical phenomena during blood collecting. We report a case of pseudo-hyperkalemia in a context of acute myeloid leukemia.

Withholding and withdrawing life prolonging treatment in the intensive care unit: a current European perspective.

BACKGROUND: Many deaths are now preceded by an end of life decision, particularly in the intensive care unit (ICU), but such practices vary considerably between countries, ICUs and individuals, depending on many factors including cultural and religious background, family and peer pressure and local practice. AIMS: In this review, we will discuss the application of the four key ethical principles--beneficence, nonmaleficence, autonomy and distributive justice--to withdrawing/withholding decisions. METHODS: Drawing data from several national and international studies, we then summarize the current situation across Europe regarding such practices before making some suggestions as to how we could facilitate the often difficult decision making process by improved communication between staff, patient and relatives.

[The intensive care department]. / Le Service des Soins Intensifs.

Intensive Care Departments are designed for the care of the critically ill, and are equipped with all the material necessary for monitoring and treatment, as well as specially trained medical, nursing, and paramedical staff. With a team of more than 170 highly qualified staff, the Department of Intensive Care at Erasme Hospital, has acquired a national and international reputation in the fields of clinical and experimental research and education, as well as for its standards of clinical practice. Clinical and experimental studies have been high in quantity and quality, and have covered all the key areas in the field of intensive care medicine: severe sepsis, multiple organ failure, transport and metabolism of oxygen, systemic and regional hemodynamic alterations (pulmonary, cerebral, hepato-splanchnic,...), metabolic disorders,... not forgetting issues associated with the complexities of medical ethics. The quality of care, clinical, scientific and personal, offered by the Department of Intensive Care at Erasme Hospital has earned it the high level reputation for which it is renowned in Belgium, and indeed worldwide.

Normovolemic hemodilution improves oxygen extraction capabilities in endotoxic shock.

We studied the effects of normovolemic hemodilution on tissue oxygen extraction capabilities in a canine model of endotoxic shock. Eighteen anesthetized and mechanically ventilated dogs underwent normovolemic hemodilution with 6% hydroxyethyl starch solution to reach hematocrit (Hct) levels around 40, 30, or 20% before the administration of 2 mg/kg of Escherichia coli endotoxin. Cardiac tamponade was then induced by repeated injections of normal saline into the pericardial sac to reduce cardiac output and study whole body oxygen extraction capabilities. Whole body critical oxygen delivery was lower in the Hct 20% and 30% groups (8.4 +/- 0.4 and 10.4 +/- 0.7 ml. kg(-1). min(-1), respectively) than in the Hct 40% group (12.8 +/- 0.8 ml. kg(-1). min(-1)) (both P < 0.005). The whole body critical oxygen extraction ratio was higher in the Hct 30% and 20% groups (49.1 +/- 8.2 and 55.2 +/- 4.6%, respectively) than in the Hct 40% group (37.1 +/- 4.4 %) (both P < 0.05). Liver critical oxygen extraction ratio was also higher in the Hct 30% and 20% groups than in the Hct 40% group. The arterial lactate concentrations and the gradient between ileum mucosal PCO(2) and arterial PCO(2) were lower in the Hct 20% and 30% groups than in the Hct 40% group. We conclude that, during an acute reduction in blood flow during endotoxic shock in dogs, normovolemic hemodilution is associated with improved tissue perfusion and increased oxygen extraction capabilities.

The hepatosplanchnic area is not a common source of lactate in patients with severe sepsis.

OBJECTIVE: To investigate the role of the splanchnic region in the hyperlactatemia of septic patients. DESIGN: Prospective, observational study. SETTING: Thirty-one-bed mixed medicosurgical intensive care unit. PATIENTS: Ninety invasively monitored and mechanically ventilated patients with severe sepsis. MEASUREMENTS AND MAIN RESULTS: Splanchnic lactate balance was measured in all patients. Splanchnic blood flow was determined by using the primed continuous indocyanine green infusion technique in 69 patients. In 71 patients, gastric mucosal Pco2 and the Pco2 gap (the difference between gastric and arterial Pco2) also were determined by using gas tonometry with an automated gas analyzer. In each patient, arterial, mixed-venous, and hepatic venous blood samples were obtained to determine hemoglobin oxygen saturations and lactate concentrations. Arterial and hepatic venous lactate concentrations were determined in triplicate and were averaged, and the arterial hepatic venous difference in lactate and lactate consumption were calculated. The splanchnic region produced lactate in only six of the 90 patients. Mean arterial pressure, cardiac index, arterial lactate, hepatic venous oxygen saturation, and catecholamine use were similar in the six patients with splanchnic lactate production and in the 84 others. The arterial hepatic venous differences in lactate and splanchnic lactate consumption were related directly to arterial lactate concentrations (y = 0.073x + 0.209, r(2) =.06, p <.05, and y = 0.06x + 0.183, r(2) =.08, p <.05, respectively) but were not related to Pco2 gap, to the gradient between mixed-venous and hepatic venous oxygen saturations, or to bilirubin concentrations. CONCLUSIONS: Splanchnic lactate release is uncommon in septic patients, even when hyperlactatemia is severe.

Diaspirin cross-linked hemoglobin improves oxygen extraction capabilities in endotoxic shock.

We studied the effects of diaspirin cross-linked hemoglobin (DCLHb), a cell-free hemoglobin derived from human erythrocytes, on blood flow distribution and tissue oxygen extraction capabilities in endotoxic shock. Eighteen pentobarbital sodium-anesthetized, mechanically ventilated dogs received 2 mg/kg of E. coli endotoxin, followed by saline resuscitation to restore cardiac filling pressures to baseline levels. The animals were randomly divided into three groups: six served as control, six received DCLHb at a dose of 500 mg/kg (group 1) and six DCLHb at a dose of 1,000 mg/kg (group 2). Cardiac tamponade was then induced by saline injection in the pericardial sac to progressively reduce cardiac index and thereby allow study of tissue oxygen extraction capabilities. DCLHb had a dose-dependent vasopressor effect but did not significantly alter cardiac index or regional blood flow. During cardiac tamponade, critical oxygen delivery was 12.8 +/- 0.7 ml. kg(-1). min(-1) in the control group, but 8.6 +/- 0.9 and 8.2 +/- 0.7 ml. kg(-1). min(-1) in groups 1 and 2, respectively (both P < 0.05 vs. control group). The critical oxygen extraction ratio was 39.1 +/- 3.1% in the control group but 58.7 +/- 12.8% and 60.2 +/- 9.0% in groups 1 and 2, respectively. We conclude that DCLHb can improve whole body oxygen extraction capabilities during endotoxic shock in dogs.

Hemoglobin solutions--not just red blood cell substitutes.

OBJECTIVE: To review current knowledge about cell-free hemoglobin solutions. DATA SOURCES: All studies involving cell-free hemoglobin were retrieved from a computerized MEDLINE search from 1980 to 1998. We also reviewed the reference lists of all available review articles and primary studies to identify references not found in the computerized search. STUDY SELECTION: Clinical and experimental studies in which cell-free hemoglobin solutions were studied. DATA EXTRACTION: From the selected studies, information was obtained regarding the experimental model or the study population in which cell-free hemoglobin solutions were investigated, the type of cell-free hemoglobin solution, their deleterious or beneficial effects, and their possible indications. DATA SYNTHESIS: In many studies, hemoglobin solutions were considered as efficient resuscitative agents and good alternatives to red blood cell transfusion, because of their marked vasopressor effect coupled with their capacity to improve the microcirculation and quickly restore metabolic parameters. Nevertheless, potential problems include an increased susceptibility to infection, immunosuppression, oxidative damage, excessive pulmonary and systemic vasoconstriction, and platelet activation. CONCLUSIONS: Hemoglobin solutions are more than mere blood substitutes. Promising effects on oxygen transport and the microcirculation need to be confirmed, and the results of continuing research are eagerly awaited.

Does gastric tonometry monitor splanchnic perfusion?

OBJECTIVE: To define whether the gastric mucosal-arterial PCO2 gradient (PCO2 gap) reliably reflects hepatosplanchnic oxygenation in septic patients. DESIGN: Prospective observational clinical study. SETTING: An adult, 31-bed medical/surgical department of intensive care of a university hospital. PATIENTS: A total of 36 hemodynamically stable, invasively monitored, mechanically ventilated, sedated, paralyzed patients with severe sepsis. INTERVENTIONS: In each patient, hepatosplanchnic blood flow was determined by the continuous indocyanine green infusion technique and gastric mucosal PCO2 by the saline tonometry technique. Suprahepatic venous blood oxygen saturation and PCO2 also were measured. The mesenteric veno-arterial PCO2 gradient was determined as the difference between the suprahepatic venous blood PCO2 and the arterial blood PCO2. MEASUREMENTS AND MAIN RESULTS: There were significant correlations between the hepatosplanchnic blood flow and the suprahepatic venous blood oxygen saturation (r2 = .56; p<.01), between the hepatosplanchnic blood flow and the mesenteric veno-arterial PCO2 gradient (r2 = .55; p<.01), and also between the suprahepatic venous blood oxygen saturation and the mesenteric veno-arterial PCO2 gradient (r2 = .64; p<.01). There was no statistically significant correlation between the PCO2 gap and the hepatosplanchnic blood flow, the suprahepatic venous blood oxygen saturation or the mesenteric veno-arterial PCO2 gradient. CONCLUSIONS: In stable septic patients, the PCO2 gap is not correlated with global indexes of gut oxygenation. The interpretation of PCO2 gap is more complex than previously thought.

A dobutamine test can disclose hepatosplanchnic hypoperfusion in septic patients.

In 36 hemodynamically stable septic patients, we explored whether changes in gastric mucosal-arterial PCO(2) gradient (PCO(2)gap) induced by a short-term dobutamine infusion may reveal hepatosplanchnic hypoperfusion. Hepatosplanchnic blood flow (HSBF) was determined by the continuous indocyanine green infusion technique and gastric mucosal PCO(2) (Pg(CO(2))) by saline tonometry. In each patient, hemodynamic measurements, blood samples, and Pg(CO(2)) determinations were performed three times: first at baseline (DOB 0), second during a dobutamine infusion at a dose of 5 microgram/kg/min (DOB 5), and third at a dose of 10 microgram/kg/min (DOB 10). The results were analyzed by Wilcoxon's matched-pairs signed rank test and are presented as medians with ranges. The PCO(2)gap decreased preferentially in groups of patients with inadequate hepatosplanchnic perfusion, i.e., with a low fractional HSBF (HSBF/CI), defined as the ratio of the HSBF to the simultaneous cardiac index, or a high gradient between the mixed venous blood and the suprahepatic blood O(2) saturations (DSvh(O(2))). In the 11 patients with a DSvh(O(2)) above 20% at baseline, PCO(2)gap decreased from 12.1 (6.3 to 19.5) mm Hg at DOB 0 to 6.2 (2.5 to 19. 3) mm Hg at DOB 5 (p < 0.001 versus DOB 0), and to 4.2 (0.1 to 35.9) mm Hg at DOB 10 (p < 0.05 versus DOB 5), whereas in the 25 patients with a DSvh(O(2)) below 20% at baseline, PCO(2)gap did not change significantly. At no time was the PCO(2)gap correlated with HSBF/CI or DSvh(O(2)). We conclude that although the PCO(2)gap does not correlate well with global indexes of gut oxygenation, such a simple dobutamine infusion test could identify patients with inadequate hepatosplanchnic perfusion.

Effects of vasoactive drugs on gastric intramucosal pH.

OBJECTIVE: To review current knowledge about the effects of vasoactive agents on gastric intramucosal pH (pHi). DATA SOURCES: All studies involving pHi and vasoactive agents were retrieved from a computerized MEDLINE search from 1980 to 1997. We also reviewed the reference lists of all available review articles and primary studies to identify references not found in the computerized searches. STUDY SELECTION: Clinical and experimental studies using dopamine, dopexamine, dobutamine, norepinephrine, epinephrine, nitric oxide, N-acetylcysteine, prostaglandins, or pentoxifylline were considered if splanchnic perfusion and/or pHi measurements were utilized. DATA EXTRACTION: From the selected studies, information was obtained regarding patient population, dosing regimen, duration of study, and effects on splanchnic blood flow (SBF), splanchnic oxygenation, and pHi. DATA SYNTHESIS: Although dopaminergic effects increase SBF, dopamine does not generally increase pHi. Data on the effects of dopexamine on pHi are scarce and inconsistent. Dobutamine can significantly increase SBF and usually increases pHi. In septic patients, norepinephrine seems to increase pHi. Epinephrine may have detrimental effects on gastric perfusion. Prostacyclin seems to increase pHi but data are limited. Insufficient evidence exists to support the beneficial effects of nitric oxide donors or blockers, pentoxifylline, or N-acetylcysteine on pHi. CONCLUSIONS: Overall, the effects of vasoactive agents on pHi are unpredictable. Among the catecholamines, dopamine is the least likely, and dobutamine the most likely, to increase pHi.

Does hepato-splanchnic VO2/DO2 dependency exist in critically ill septic patients?

Since the gradient between the mixed venous and hepatic vein oxygen saturation (DSO2) is often increased in septic patients, we suspected these patients may have an imbalance between oxygen supply and demand in the hepato-splanchnic area. In 42 septic patients, hepato-splanchnic blood flow was determined by the indocyanine green clearance method with hepatic vein catheterization. The relationships between hepato-splanchnic oxygen delivery (DO2spla) and consumption (VO2spla) were analyzed during an increase in blood flow induced by a dobutamine infusion at doses up to 10 microg/kg x min. In 14 patients, positive end-expiratory pressure (PEEP) was also increased up to 20 cm H2O. The patients were separated according to their DSO2 (Group I: DSO2 < 10%, n = 13; and Group II: DSO2 > 10%, n = 29). Although DO2spla increased similarly in both groups, VO2spla only increased in Group II (from 45+/-22 to 59+/-39 ml/min x M2, p < 0.01). The slope of the VO2spla/DO2spla relationship was higher in Group II than in Group I (31.2+/-16.7 versus 10.4+/-5.1%, p < 0.001) and was similar during dobutamine and PEEP (21.9+/-14.2 versus 21.9+/-14.0%, p = NS). In conclusion, VO2spla increased only in septic patients with an increased DSO2 indicating splanchnic dysoxia. The similar slope observed with dobutamine and PEEP suggests that a thermogenic effect was unlikely.

Lactate production by the lungs in acute lung injury.

Arteriovenous differences in lactate (AVLAC) across the lungs are usually small and close to zero. However, it has recently been reported that the lungs can produce increased amounts of lactate in some patients with acute respiratory distress syndrome (ARDS). The aim of this study was to evaluate lactate production in various types of acute lung injury requiring mechanical ventilation and hemodynamic monitoring. Since the differences involved are usually small, minor errors in lactate measurement could greatly influence AVLAC. Based on an analysis of these errors (see text for details), we averaged five arterial and venous samples for each measurement. We investigated 122 patients: 43 with acute lung injury (ALI), nine with cardiogenic pulmonary edema (CPE), 37 with bronchopneumonia (BPN), seven with single lung transplantation (LTX), and 26 with other causes of respiratory failure (OTHER). There was no difference in arterial lactate between the various groups. AVLAC was higher in patients with ALI than in the other groups (0.20+/-0.23 versus 0.07+/-0.11 mEq/L). In patients with ALI, AVLAC was proportional to the Murray's lung injury score (-0.032+/-0.032x; r = 0.46, p < 0.01). Lung lactate production was calculated as the product of the cardiac index times AVLAC and was significantly higher in patients with ALI than in the other groups (0.69+/-0.88 versus 0.19+/-0.30 mEq/min; p < 0.05). In patients with ALI, lung lactate production was inversely related to the PaO2/FIO2 (1.42 - 0.005x; r = 0.35, p < 0.05) but directly related to the venous admixture (-0.36 + 0.003x; r = 0.49, p < 0.01) and the lung injury score (-0.19 + 0.36x; r = 0.45, p < 0.01). Lung lactate production was not significantly related to arterial lactate levels. These data indicate that AVLAC and lung lactate production can be increased in patients with ARDS but remain within the normal range in other types of respiratory failure.

Monitoring gastric mucosal carbon dioxide pressure using gas tonometry: in vitro and in vivo validation studies.

BACKGROUND: Saline gastric tonometry of carbon dioxide has been proposed as a means to assess the adequacy of splanchnic perfusion. However, this technique has several disadvantages, including the long time interval needed for gases to reach equilibrium in saline milieu. Thus the authors evaluated a system that uses a gas-filled instead of a saline-filled gastric balloon. METHODS: In vitro, we simultaneously placed two tonometry catheters in an equilibration water bath maintained at a predetermined and constant pressure of carbon dioxide (P(CO2)). The first catheter's balloon was filled with air and the second with saline. The performance of gas tonometry was tested by comparing the P(CO2) measurements of the bath obtained via gas tonometry (PgCO2) to the P(CO2) measurements of direct bath samples (PbathCO2). These results were also compared with the P(CO2) measurements obtained simultaneously by saline tonometry (PsCO2). The response time of gas versus saline tonometry was also studied. In vivo, the performance of gas tonometry was tested comparing the measurements of gastric intramucosal P(CO2) obtained by gas tonometry (PgCO2) at different equilibration times with those obtained by saline tonometry (PsCO2) using an equilibration time of 30 min. Two nasogastric tonometry catheters were placed simultaneously in seven stable patients in the intensive care unit. The first balloon was filled with air and the second with saline. RESULTS: In vitro, there was a close correlation between PgCO2 and PbathCO2, for each level of PbathCO2, and for each different gas equilibration time. For an equilibration time of 10 min at a PbathCO2 level of approximately 40 mmHg, the bias of the gas device defined as the mean of the differences between PbathCO2 and PgCO2 and its precision defined as the standard deviation of the bias, were -0.3 mmHg and 0.7 mmHg, respectively. Using the same definitions, the bias and precision of saline tonometry were 11.2 mmHg and 1.4 mmHg, respectively. If the equilibration time-dependent correction factor provided by the catheter manufacturer for saline tonometry was applied, the bias and precision were -6.9 mmHg and 2.9 mmHg, respectively. In vivo, using an equilibration time of 10 min for gas and 30 min for saline tonometry, there was a close correlation between the two techniques (r2 = 0.986). A Bland and Altman analysis revealed a bias (+/- 2 SD) of 0.1 +/- 6.8 mmHg. The correlation between the two methods was not improved if we prolonged the equilibration time of the gas tonometer. CONCLUSIONS: Gas tonometry is comparable to saline tonometry for measuring gastric intramucosal P(CO2). Because gas tonometry is easier to automate, it may offer advantages over saline tonometry.

[Snake bites]. / Morsures de serpent.

Snake bites are a rare occurrence in Belgium. Nevertheless, all doctors should know how to react to this potentially very dangerous emergency. A snakebite does not necessarily result in poisoning: the effects can range from a little local discomfort to a severe systemic reaction with multiple organ failure. Therefore, all snake bites must be treated as serious and should receive adequate treatment. At the same time, hysterical over reaction must be avoided for this risks complications. This article reviews the principal elements of snake bite treatment: from the emergency stage through to stabilization in the hospital. Key points raised are the necessity to immobilize the affected region, to establish adequate perfusion and to anticipate infectious complications. Serum therapy indications are reviewed together with adjuvant interventions such as corticotherapy and heparin therapy.