Christian Laplace

Plasma-induced endothelial oxidative stress is related to the severity of septic shock.

Objective:To estimate the capacity of plasma from septic shock patients to induce in vitro reactive oxygen species (ROS) production by endothelial cells and to analyze whether ROS production is related to the severity of the septic shock. Design:Prospective, observational study. Setting:Medical intensive care unit in a university hospital. Patients:Twenty-one patients with septic shock. Interventions:The in vitro capacity of plasma from septic shock patients to induce ROS production by naive human umbilical vein endothelial cells (HUVEC) was quantified by using a fluorescent probe (2′,7′-dichlorodihydrofluorescein diacetate). Measurements and Main Results:Blood samples were collected on day 1, day 3, and day 5 from 21 consecutive septic shock adult patients and from ten healthy volunteers. Patients mean age was 58 yrs old, mean Sequential Organ Failure Assessment (SOFA) score at admission was 12, mean severity illness assessed by Simplified Acute Physiology Score (SAPS) II was 53, and the mortality rate was 47%. In addition to assessment of in vitro ROS generation by HUVEC, oxidative stress in blood was evaluated by measuring lipid peroxidation products and enzymatic and nonenzymatic antioxidants. Septic shock was associated with oxidative stress and an imbalance in antioxidant status. As compared with controls, plasma-induced ROS production by naïve HUVEC was significantly higher in septic shock. Moreover ROS production was significantly correlated with SAPS II (p = .028) and SOFA values (p = .0012) and was higher in nonsurvivors than in survivors. In contrast, no correlation was found between the severity of the septic shock and any of the levels of lipid peroxidation products or enzymatic and nonenzymatic antioxidants. Conclusion:Plasma from septic shock patients induces ROS formation by naive HUVEC, and the extent of ROS formation correlates with mortality and with criteria of the severity of septic shock as SOFA score and SAPS II.

One-day quantitative cross-sectional study of family information time in 90 intensive care units in France

Rationale: Providing family members with clear, honest, and timely information is a major task for intensive care unit physicians. Time spent informing families has been associated with effectiveness of information but has not been measured in specifically designed studies. Objectives: To measure time spent informing families of intensive care unit patients. Methods: One‐day cross‐sectional study in 90 intensive care units in France. Measurements: Clocked time spent by physicians informing the families of each of 951 patients hospitalized in the intensive care unit during a 24‐hr period. Main Results: Median family information time was 16 (interquartile range, 8–30) mins per patient, with 20% of the time spent explaining the diagnosis, 20% on explaining treatments, and 60% on explaining the prognosis. One third of the time was spent listening to family members. Multivariable analysis identified one factor associated with less information time (room with more than one bed) and seven factors associated with more information time, including five patient‐related factors (surgery on the study day, higher Logistic Organ Dysfunction score, coma, mechanical ventilation, and worsening clinical status) and two family‐related factors (first contact with family and interview with the spouse). Median information time was 20 (interquartile range, 10–39) mins when three factors were present and 106.5 (interquartile range, 103–110) mins when five were present. Conclusion: This study identifies factors associated with information time provided by critical care physicians to family members of critically ill patients. Whether information time correlates with communication difficulties or communication skills needs to be evaluated. Information time provided by residents and nurses should be studied.

Endothelial oxidative stress induced by serum from patients with severe trauma hemorrhage

ObjectiveShock induces oxidative stress by ischemia-reperfusion phenomenon. Endothelial cells are involved in the inflammatory response and oxidative stress responsible for microcirculation impairment and organ failure. We examined the potential of serum from patients to induce in vitro reactive oxygen species production by cultured human umbilical vein endothelial cells (HUVECs).PatientsThree groups were compared: hemorrhagic shock trauma patients, isolated brain injured patients, and healthy volunteers.MethodsIn the hemorrhagic shock group we sought a correlation between reactive oxygen species production and severity of shock. Serum was separated and perfused in an in vitro model of perfused HUVECs. Ex vivo reactive oxygen species production was assessed by fluorescence microscopy using dichlorodihydrofluorescein, an intracellular dye oxidized by H2O2. Results are expressed in proportional change from baseline and normalized by protidemia to control for variation related to hemodilution.ResultsReactive oxygen species production by endothelial cells exposed to serum from hemorrhagic shock patients (46.2±24.9%) was significantly greater than in those with brain injury (3.9±35.1%) and in healthy volunteers (−6.8±5.8%). In the hemorrhagic shock group dichlorodihydrofluorescein fluorescence was strongly correlated positively to Simplified Acute Physiology Score II and lactatemia and negatively to [HCO3−].ConclusionsSerum from trauma patients with hemorrhagic shock induces reactive oxygen species formation in naive endothelial cells which is correlated to shock severity.

The Limits of Succinylcholine for Critically Ill Patients

BACKGROUND:Urgent tracheal intubations are common in intensive care units (ICU), and succinylcholine is one of the first-line neuromuscular blocking drugs used in these situations. Critically ill patients could be at high risk of hyperkalemia after receiving succinylcholine because one or more etiologic factors of nicotinic receptor upregulation can be present, but there are few data on its real risk. Our objectives in this study were to determine the factors associated with arterial potassium increase (&Dgr;K) and to assess the occurrence of acute hyperkalemia ≥6.5 mmol/L after succinylcholine injection for intubation in the ICU. METHODS:In a prospective, observational study, all critically ill patients intubated with succinylcholine in an ICU were screened. Only intubations with arterial blood gases and potassium measurements before and after (Kafter) a succinylcholine injection were studied. RESULTS:During 18 months, 131 critically ill patients were intubated after receiving succinylcholine with arterial potassium before and after intubation (Kafter) for a total of 153 intubations. After multivariate analysis, the only factor associated with &Dgr;K was the length of ICU stay before intubation (&rgr; = 0.561, P < 0.001). The factors associated with Kafter ≥6.5 mmol/L (n = 11) were the length of ICU stay (P < 0.001) and the presence of acute cerebral pathology (P = 0.047). The threshold of 16 days was found highly predictive of acute hyperkalemia ≥6.5 with 37% (95% confidence interval: 19%–58%) of Kafter ≥6.5 after the 16th day compared with only 1% (95% confidence interval: 0%–4%) of Kafter ≥6.5 when succinylcholine was injected during the first 16 days. CONCLUSIONS:This study shows that the risk of &Dgr;K after succinylcholine injection is strongly associated with the length of ICU stay. The risk of acute hyperkalemia ≥6.5 mmol/L is highly significant after 16 days.