乳酸水平监测在治疗早期重症监护患者中的指导作用

背景和目的:乳酸水平增高与患者的致病率和病死率显著相关.该研究探讨了在危重患者的早期治疗中,监测乳酸水平是否可以改善患者的预后及其效果.方法:将入住ICU时血乳酸水平≥3.0 mmol/L(3.0 mEq/L)的患者随机分为2组,乳酸组以乳酸水平指导治疗,使患者在最初8h内乳酸水平每2h 下降20%以上;对照组仅有基线乳酸水平,不进行乳酸水平监测.     

DLA-identical bone marrow grafts after low-dose total body irradiation: effects of high-dose corticosteroids and cyclosporine on engraftment

Previous studies found that marrow allografts from DLA-identical littermates resulted in survival of 60% of recipient dogs after an otherwise lethal dose of 450 cGy of total body irradiation (TBI), either because of successful allografts or autologous recovery after rejection of the allografts. Forty percent of dogs died with marrow aplasia after allograft rejection. The current study asked whether allogeneic engraftment could be enhanced and survival improved by treating allograft recipients with high doses of corticosteroids or with cyclosporine (CSP), administered either before or after transplantation. Five dogs in group 1 received corticosteroids beginning on day -5 and ending on day 32 after transplant. The starting dose was 12.5 mg of prednisone per kilogram orally twice daily. All five dogs rejected their allografts; three died early with marrow aplasia and two showed endogenous marrow recovery. Nine dogs received CSP from day -6 to day -1 before transplantation at a dose of 20 mg/kg/d intravenously administered in divided doses. All nine dogs rejected the marrow allograft; six died with marrow aplasia and three survived with endogenous marrow recovery. Seven dogs received CSP after transplantation at a dose of 30 mg/kg/d orally from day -1 to day 35. All seven had sustained allografts (two mixed chimeras and five complete donor-type chimeras) and became healthy long-term survivors without graft-versus-host disease. These results extend previous observations and confirm that grafts of marrow from DLA-identical littermates improved survival of dogs exposed to low but otherwise lethal doses of TBI. Additional therapy with high-dose corticosteroids administered peritransplantation and posttransplantation or CSP administered before transplantation neither enhanced the rate of allogeneic engraftment nor improved survival; however, CSP administered after transplantation resulted in successful allografts and event-free survival in all cases.     

Blood transfusions increase circulating plasma free hemoglobin levels and plasma nitric oxide consumption: a prospective observational pilot study

ABSTRACT: INTRODUCTION: The increasing number of reports on the relation between transfusion of stored red blood cells (RBCs) and adverse patient outcome has sparked an intense debate on the benefits and risks of blood transfusions. Meanwhile, the pathophysiological mechanisms underlying this postulated relation remain unclear. The development of hemolysis during storage might contribute to this mechanism by release of free hemoglobin (fHb), a potent nitric oxide (NO) scavenger, which may impair vasodilation and microcirculatory perfusion after transfusion. The objective of this prospective observational pilot study was to establish whether RBC transfusion results in increased circulating fHb levels and plasma NO consumption. In addition, the relation between increased fHb values and circulating haptoglobin, its natural scavenger, was studied. METHODS: Thirty patients electively received 1 stored packed RBC unit (n = 8) or 2 stored packed RBC units (n = 22). Blood samples were drawn to analyze plasma levels of fHb, haptoglobin, and NO consumption prior to transfusion, and 15, 30, 60 and 120 minutes and 24 hours after transfusion. Differences were compared using Pearson's chi-square test or Fisher's exact test for dichotomous variables, or an independent-sample t test or Mann-Whitney U test for continuous data. Continuous, multiple-timepoint data were analyzed using repeated one-way analysis of variance or the Kruskall-Wallis test. Correlations were analyzed using Spearman or Pearson correlation. RESULTS: Storage duration correlated significantly with fHb concentrations and NO consumption within the storage medium (r = 0.51, P < 0.001 and r = 0.62, P = 0.002). fHb also significantly correlated with NO consumption directly (r = 0.61, P = 0.002). Transfusion of 2 RBC units significantly increased circulating fHb and NO consumption in the recipient (P < 0.001 and P < 0.05, respectively), in contrast to transfusion of 1 stored RBC unit. Storage duration of the blood products did not correlate with changes in fHb and NO consumption in the recipient. In contrast, pre-transfusion recipient plasma haptoglobin levels inversely influenced post-transfusion fHb concentrations. CONCLUSION: These data suggest that RBC transfusion can significantly increase post-transfusion plasma fHb levels and plasma NO consumption in the recipient. This finding may contribute to the potential pathophysiological mechanism underlying the much-discussed adverse relation between blood transfusions and patient outcome. This observation may be of particular importance for patients with substantial transfusion requirements.     

Effect of phototherapy on thyroid stimulatory hormone and free thyroxine levels

Objective : To study the effect of phototherapy for neonatal hyperbilirubinaemia on thyroid function as neonatal thyroid screening is sometimes performed during exposure to phototherapy. Methodology : Infants with non-haemolytic hyperbilirubinaemia were sequentially allocated to fibre-optic phototherapy, conventional daylight phototherapy, or a combination of both. Bilirubin concentration was monitored 12 hourly by capillary blood sampling; venous blood was sampled for thyroid stimulating hormone (TSH) and free thyroxine (fT₄) determinations, at start of exposure, at 24 h, end of exposure and 1 day later. Comparable unexposed infants served as controls. Results : All 123 study infants and 25 controls remained well during the study. Bilirubin levels declined during phototherapy, being most rapid in the combination group. The TSH and fT₄ values at start of exposure were 3.86 ± 0.41 mU/L (mean ± SEM) and 33.20 ± 1.16 pmol/L, respectively, in the fibre-optic group, 3.62 ± 0.38 mU/L and 37.22 ± 1.76 pmol/L in the daylight group, and 4.40 ± 0.48 mU/L and 29.91 ± 1.13 pmol/L in the combined group, compared with 5.77 ± 0.40 mU/L and 34.46 ± 1.68 pmol/L in the control group. The TSH and fT₄ values declined with increasing age in the phototherapy and control groups with end of exposure values of 2.90 ± 0.28mU/L and 27.71 ± 0.71 pmol/L, 2.77 ± 0.31 mU/L and 33.52 ± 1.22pmol/L, and 3.44 ± 0.30 mU/L and 27.54 ± 0.88 pmol/L, respectively, compared with 4.21 ± 0.61 mU/L and 27.19 ± 2.33 pmol/L (at 72 h) in the control group. The pattern of TSH and fT₄ decline in the exposed and control groups was similar, being related to increasing age. Conclusions : The validity of neonatal thyroid screening is not affected by fibre-optic or conventional phototherapy or by both combined.     

Macronodular hepatic tuberculosis associated with portal vein thrombosis and portal hypertension

Tuberculosis (TB) of the liver is usually associated with miliary spread. Macronodular TB of the liver is rare. A case of macronodular TB of the liver in a 31‐year‐old woman causing portal vein thrombosis and portal hypertension is presented. Ultrasound and CT appearances are described. There was coexistent ileo‐caecal TB with extensive mesenteric and retroperitoneal lymphadenopathy. Macronodular TB should be considered in the differential diagnosis when a patient presents with multiple calcified masses in the liver with portal vein thrombosis and portal hypertension.     

Characteristics of the synergistic actions of platelet agonists

Platelets are activated by many different agonists that act synergistically. Since there is a characteristic pattern of responses to each agonist, and since there is a clear distinction between weak and strong agonists, understanding the nature of the synergism and its physiologic significance requires characterization of the pattern of responses to the synergistic action of the various agonists. Shape change, aggregation, and secretion of ATP by human platelets in citrated plasma were analyzed after activation by ADP, epinephrine, arachidonic acid, gamma-thrombin, or collagen, either singly or in pairs. The patterns of responses were characteristic of the agonist in higher concentration relative to its threshold concentration; if neither was clearly higher, the pattern of responses was intermediate between the responses characteristic of each agonist. No combination of weak agonists had the characteristics of a strong agonist. These results help define the extent to which platelet responses can be attributed to the synergistic actions of weak agonists.