Lajos Bogár

Hemodynamic and respiratory changes during lung recruitment and descending optimal positive end-expiratory pressure titration in patients with acute respiratory distress syndrome.

OBJECTIVES To investigate respiratory and hemodynamic changes during lung recruitment and descending optimal positive end-expiratory pressure (PEEP) titration. DESIGN Prospective auto-control clinical trial. SETTING Adult general intensive care unit in a university hospital. PATIENTS Eighteen patients with acute respiratory distress syndrome. INTERVENTIONS Following baseline measurements (T0), PEEP was set at 26 cm H2O and lung recruitment was performed (40/40-maneuver). Then tidal volume was set at 4 mL/kg (T26R) and PEEP was lowered by 2 cm H2O in every 4 mins. Optimal PEEP was defined at 2 cm H2O above the PEEP where Pao2 dropped by > 10%. After setting the optimal PEEP, the 40/40-maneuver was repeated and tidal volume set at 6 mL/kg (T(end)). MEASUREMENTS AND MAIN RESULTS Arterial blood gas analysis was done every 4 mins and hemodynamic measurements every 8 mins until T(end), then in 30 (T30) and 60 (T60) mins. The Pao2 increased from T0 to T(end) (203 +/- 108 vs. 322 +/- 101 mm Hg, p < .001), but the extravascular lung water (EVLW) did not change significantly. Cardiac index (CI) and the intrathoracic blood volume (ITBV) decreased from T0 to T26R (CI, 3.90 +/- 1.04 vs. 3.62 +/- 0.91 L/min/m2, p < .05; ITBVI, 832 +/- 205 vs. 795 +/- 188 m/m2, p < .05). There was a positive correlation between CI and ITBVI (r = .699, p < .01), a negative correlation between CI and central venous pressure (r = -.294, p < .01), and no correlation between CI and mean arterial pressure (MAP). CONCLUSIONS Following lung recruitment and descending optimal PEEP titration, the Pao2 improves significantly, without any change in the EVLW up to 1 hr. This suggests a decrease in atelectasis as a result of recruitment rather than a reduction of EVLW. There is a significant change in CI during the maneuver, but neither central venous pressure, heart rate, nor MAP can reflect these changes.

Short-term effectiveness of different volume replacement therapies in postoperative hypovolaemic patients.

Background and objective To examine the kinetics of volume loading with crystalloid and colloid infusions in critically ill patients after major surgery, using the pulse contour cardiac output (PiCCO) monitoring technique. Methods This prospective, randomized, multicentre study of 11 ICUs involved 200 mixed postoperative hypovolaemic patients (50 patients per group) in Hungary. Patients received 10 ml kg−1 of lactated Ringers solution, succinylated gelatin 4% w/v, 130/0.4 hydroxyethyl starch 6% w/v (HES) or human albumin 5% w/v over 30 min. A complete haemodynamic profile was obtained at 30, 45, 60, 90 and 120 min after baseline. The peak haemodynamic effects, the 120 min changes compared with baseline, the area under the curve (AUC) for the haemodynamic parameters over 120 min and the haemodilution effect of the solutions were analysed. The primary outcome was to compare the AUCs and the secondary outcome was to evaluate the haemodynamic changes at 120 min. Results There were significant differences in the AUCs of the haemodynamic parameters between colloids and lactated Ringers solution in the cardiac index and global end-diastolic volume index (GEDVI); human albumin vs. lactated Ringers solution in stroke volume variation (SVV); and succinylated gelatin, HES vs. lactated Ringers solution in the oxygen delivery index (DO2I). Colloid infusions (mainly HES and human albumin) at 120 min caused significant changes in central venous pressure, cardiac index, GEDVI, SVV, DO2I and central venous oxygen saturation compared with baseline. The haemodilution effect was significantly greater in colloids vs. lactated Ringers solution. Conclusion In postoperative hypovolaemic patients, lactated Ringers solution can significantly improve haemodynamics at the end of volume loading, but this effect completely disappears at 120 min. Ten millilitres per kilogram of colloid bolus (especially HES) improved the haemodynamics at 120 min; however, this was by only 5–25% compared with baseline. The colloids caused significantly larger AUCs than lactated Ringers solution, but only in the cardiac index, GEDVI and DO2I, plus human albumin in the SVV.

Burn trauma induces early HMGB1 release in patients: Its correlation with cytokines

High-mobility group box protein 1 (HMGB1) is a nuclear protein that may be released actively from monocytes and macrophages or passively from necrotic or damaged cells. Several experimental data suggest that burn injury is accompanied by elevated plasma HMGB, but there are only few data available about its changes in burned patients. The aim of this study was to follow the time course and the prognostic value of plasma HMGB1 and cytokine changes in patients with severe burn injury affecting more than 10% of body surface area (n = 26). Blood samples were taken on admission and on the following 5 days. Plasma HMGB1 concentration was measured by the enzyme-linked immunosorbent assay method, whereas IL-6, IL-8, and IL-10 were assayed by the cytometric bead array kit. The HMGB1 and IL-10 concentrations were elevated on admission and gradually decreased thereafter. Significant differences were observed between survivors and nonsurvivors in HMGB1 (P < 0.01) and IL-10 (P < 0.001) concentrations on admission with higher levels in nonsurvivors. IL-6 and IL-8 started to increase markedly from day 2. Positive correlation (r = 0.669, P < 0.01) was found between burned body surface and HMGB1 on admission. Receiver operating characteristic analysis of data on admission showed that at a level of 16 ng/mL, HMGB1 indicated lethality, with 75.0% sensitivity and 85.7% specificity. Using the cutoff level of 14 pg/mL, IL-10 predicted intensive care unit mortality, with 85.7% sensitivity and 84.2% specificity. Very early HMGB1 and IL-10 release may have an important impact on the immune function of patients after burn trauma.

Effect of N-acetylcysteine treatment on oxidative stress and inflammation after severe burn

Oxidative stress and inflammation generate edema in burns. The aim of our study was to assess effect of N-acetylcysteine (NAC) on oxidative stress, inflammation, fluid requirement, multiple organ dysfunction (MOD) score and vasoactive drug requirement. In this study 15 patients were on standard therapy, whereas for other 15 patients NAC was supplemented. Blood samples were taken on admission and on the next five consecutive mornings. Levels of malondialdehyde, protein sulfhydril (PSH) groups, reduced gluthation (GSH), activity of myeloperoxidase, catalase and superoxide dismutase enzymes and induced free radical generating capacity were measured as well as concentrations of TNF-α, IL-6, IL-8, and IL-10. MOD score, use of vasopressor agents and fluid utilisation were recorded daily. NAC treatment increased GSH level on days 4-5 (p<0.05) and PSH level on days 2-6 (p<0.05) compared to controls. Plasma IL-6 was lower on days 4-5 (p<0.05), IL-8 on days 4-6 (p<0.05) and IL-10 on days 4-6 (p<0.05) in NAC group. NAC group received less catecholamines than controls (p<0.01) from day 4 without significant differences in MOD score. NAC treatment is associated with a diminished oxidative stress reflected in preserved antioxidant levels, lower inflammation mirrored in lower interleukin levels and less vasopressor requirement.

Time course of pro- and anti-inflammatory cytokine levels in patients with burns—Prognostic value of interleukin-10

INTRODUCTION Trends and the prognostic value of cytokine responses to severe burns have not been fully examined in humans. Therefore, the aim of this study was to determine the time course and prognostic value of pro- and anti-inflammatory cytokines in the immediate post-burn period. PATIENTS AND METHODS Blood samples were taken for measuring IL-1 beta, IL-6, IL-8, IL-10, IL-12p70 and TNF-alpha concentrations from patients with more than 20% burned surface area on admission and on 5 consecutive days. Development of sepsis was assessed using standard criteria twice a day. RESULTS IL-12p70 remained under assay detection levels in the study period. IL-1 beta and TNF-alpha could be detected in stimulated blood samples with higher levels in survivors (n=21). IL-6 on days 4-5 and IL-8 on days 4-6 in non-stimulated plasma showed significant elevation in non-survivors (n=18) whereas in stimulated blood its levels did not differ significantly. IL-10 levels were significantly higher in non-survivors during the study period in non-stimulated, and except day 6 in stimulated blood. Using the cut-off level of 14 pg ml(-1) for IL-10 predicted ICU mortality with 85.4% sensitivity and 84.2% specificity on admission. CONCLUSION Early anti-inflammatory excess had a bad prognosis for patients suffering from severe burns.

Dynamic changes of matrix metalloproteinases and their tissue inhibitors in severe sepsis

PURPOSE Little is known about the dynamic changes of matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) in sepsis. Our aim was therefore to investigate the time course of MMPs and their inhibitors in patients experiencing severe sepsis. METHODS Our prospective controlled analysis included 38 patients with severe sepsis. Plasma levels of MMP-2, MMP-9, TIMP-1, and TIMP-2 were measured daily at a 5-day-long period with enzyme-linked immunosorbent assay. Seventeen healthy volunteers were invited as controls. RESULTS MMP-2 showed no difference compared to controls, whereas significantly elevated MMP-9 levels were detected on admission (P < .005). Significantly elevated but declining TIMP-1 levels were measured during the whole trial (P < .002-.004). Except for the second day, TIMP-2 levels were significantly lower than controls (P < .05-.009). MMP2/TIMP-1 ratios were significantly lower in septic patients (P < .03-.006), whereas MMP-2/TIMP-2 ratios were elevated throughout our study (P < .03-.006). MMP-9/TIMP-1 ratios were significantly lower at the first 3 days (P < .05-.008). MMP-9/TIMP-2 was significantly elevated on admission (P < .006). CONCLUSIONS Our research is the first follow-up study dealing with MMPs, TIMPs, and their ratios in severe sepsis. Our results indicate that MMPs and TIMPs may play a crucial role in severe sepsis, especially TIMP-1, MMP-9, and possibly TIMP-2, after an extensive study.

Impaired Function of Innate T Lymphocytes and NK Cells in the Acute Phase of Ischemic Stroke

Background: Functional alterations of innate lymphocytes, which can mount rapid immune responses and shape subsequent T cell reactions, were examined in the acute phase of ischemic stroke. Methods: Frequencies, intracellular perforin and interferon-γ (IFN-γ) expression of Vδ2 T cells, CD3+ CD56+ natural killer T (NKT)-like and NK cells were examined in the peripheral blood of 20 healthy controls and 28 patients within 6 h of the onset of acute ischemic stroke and after 72 h by flow cytometry. Cytokine production of isolated NKT-like and NK cells following in vitro activation was measured by cytometric bead array. NK cytotoxicity was examined in the peripheral blood mononuclear cells. Results: Percentages of Vδ2, NKT-like and NK cells were constant, and similar to percentages in healthy subjects. In contrast, proinflammatory intracellularIFN-γ expression by Vδ2 T cells, NKT-like cells and NK cells and IFN-γ production by isolated NK cells in culture was low at 6 h and reached the level of healthy subjects by 72 h after stroke. Production of anti-inflammatory cytokines was unaltered. Intracellular perforin expression by Vδ2 T cells, NKT-like cells and NK cells, and NK cytotoxicity was low at 6 h, and reached the level of healthy subjects by 72 h. Increases in IFN-γ and perforin expression by Vδ2 T cells correlated with clinical improvement indicated by decreases in NIHSS scores. Conclusions: Pro-inflammatory and cytotoxic responses of NK, NKT-like and Vδ2 T cells become acutely deficient in ischemic stroke, which may contribute to an increased susceptibility to infections.

Microparticles and acute renal dysfunction in septic patients

PURPOSE The role of microparticles (MPs) in the pathogenesis of sepsis is not completely elucidated. We aimed to assess changes in the number of MPs during severe sepsis to follow the effect of sepsis-related organ failures, particularly renal impairment, an independent mortality factor of sepsis. MATERIALS AND METHODS Thirty-seven severe septic patients and 20 controls were enrolled. Patient status as well as organ failure-related laboratory markers was followed up to 5 consecutive days. Microparticles (annexin V+ events in MP size gate) of platelet (CD41, CD42a, and PAC1), monocyte (CD14), and myeloid cell line (CD13) origin were measured using flow cytometry. RESULTS Significantly increased total MP and CD41-, CD42a-, and PAC1-positive particle numbers were found in septic patients compared with controls. Actual number of organ dysfunctions on sample collection showed no correlation with MP numbers. Septic patients with renal dysfunction showed an increase in total MP, CD41(+), and CD13(+) particle numbers on admission. Amounts of platelet-derived CD42a(+) particles from patients with sepsis-related renal injury correlated negatively with actual blood urea nitrogen and creatinine concentrations. CONCLUSION The increased numbers of platelet-derived MPs in severe septic patients emphasize the possible contribution of the hemostasis system in the development of sepsis-related renal impairments.

Effects of fluid resuscitation methods on burn trauma-induced oxidative stress.

The aim of the study was to analyze the oxidative stress response after severe burn injury. We studied the effect of two methods of fluid resuscitation regimes on the oxidative stress reaction. Sixteen patients were involved in the study. Inclusion criteria were the presence of flame burn injury affecting >20% of BSA and in-hospital fluid resuscitation started within 3 hours after injury. Patients were randomly assigned into two groups. In the first group (n = 8), the fluid resuscitation was guided by the hourly urine output and in the second (n = 8), by the intrathoracic blood volume index. Blood sample was taken from the patients at admission and on the following five mornings. White blood cell count normalized by the third day in both groups, but the relative number of granulocytes and lymphocytes significantly (P < .05) diverged between hourly urine output and intrathoracic blood volume index groups from the fourth day of trauma. Plasma malondialdehyde level (P < .05 vs control population), reactive oxygen species production in whole blood (P < .05 vs control population), and catalase activity were elevated, whereas glutathione, plasma sulfhydryl groups level (P < .05 vs control population), and superoxide dismutase enzyme activity lowered in both groups. Our results confirmed that burn injury induces pronounced oxidative stress. The main finding is that fluid resuscitation regimes have different impact on prooxidant status, mainly on the granulocyte function but not on the changes in endogenous antioxidants in burned patients.

Factors affecting fluid requirement on the first day after severe burn trauma.

Background:  Parkland formula (PF) is the most often used schema for calculating intravenous resuscitation fluid requirement in burn patients. Some studies have reported that PF underestimates the fluid requirement in 45–63% of patients. The aim of this retrospective study was to analyse factors influencing first‐day intravenous fluid replacement set for a targeted urinary output in severely burnt patients.