Objective: Hyperglycemia is common in critically ill patients, even in those without diabetes mellitus. Aggressiveglycemic control may reduce mortality in this population. However, the relationship between mortality, the control of hyperglycemia, and the administration of exogenous insulin is unclear. The objective was to determine whether blood glucose level or quantity of insulin administered is associated with reduced mortality in critically ill patients. Methods: This was a single‐center, prospective, observational study of 531 patients (median age, 64 years) newly admitted over the first 6 months of 2002 to an adult intensive care unit (ICU) in a UK national referral center for cardiorespiratory surgery and medicine. The primary end point was intensive care unit (ICU) mortality. Secondary end points were hospital mortality, ICU and hospital length of stay, and predicted threshold glucose level associated with risk of death. Results: Of 531 patients admitted to the ICU, 523 under‐went analysis of their glycemic control. Twenty‐four‐hour control of blood glucose levels was variable. Rates of ICU and hospital mortality were 5.2% and 5.7%, respectively; median lengths of stay were 1.8 (interquartile range, 0.9 to 3.7) days and 6 (inter‐quartile range, 4.5 to 8.3) days, respectively. Multivariable logistic regression demonstrated that increased administration of insulin was positively and significantly associated with ICU mortality (odds ratio, 1.02 [95% confidence interval, 1.01 to 1.04] at a prevailing glucose level of 111 to 144 mg/dL [6.1 to 8.0 mmol/L] for a 1‐IU/day increase), suggesting that mortality benefits are attributable to glycemic control rather than increased administration of insulin. Also, the regression models suggest that a mortality benefit accrues below a predicted threshold glucose level of 144 to 200 mg/dL (8.0 to 11.1 mmol/L), with a speculative upper limit of 145 mg/dL (8.0 mmol/L) for the target blood glucose level. Conclusions: Increased insulin administration is positively associated with death in the ICU, regardless of the prevailing blood glucose level. Thus control of glucose levels rather than of absolute levels of exogenous insulin appears to account for the mortality benefit associated with intensive insulin therapy demonstrated by others.

Activated neutrophils play a major role in the pathogenesis of acute respiratory distress syndrome (ARDS), and persistence of pulmonary neutrophilia is related to poor survival. Interleukin (IL)‐8 is implicated in recruiting neutrophils to the lungs but it has been postulated that granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) and granulocyte colony‐stimulating factor (G‐CSF), which can promote the survival of neutrophils by delaying apoptosis, may prolong the inflammatory response. The aim of this study was to investigate the levels of GM‐CSF and G‐CSF in the lungs of patients with ARDS and determine their relationship relative to IL‐8 with levels of neutrophils and clinical outcome. The lungs of 31 patients with ARDS were sampled by means of bronchoalveolar lavage (BAL) and assays of the three cytokines were conducted via enzyme‐linked immunosorbent assay. GM‐CSF, G‐CSF and IL‐8 were all increased in the patients compared to healthy controls but concentrations of GM‐CSF were much lower than those of G‐CSF and IL‐8 (GM‐CSF

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We studied the effects of the potent inflammatory mediator, platelet-activating factor (PAF), on vascular permeability in airways (and other tissues) of guinea pigs by measuring extravasation of circulating Evans blue dye. PAF caused a dose-dependent increase in vascular permeability. At 1 ng/kg iv, PAF caused an increase in Evans blue extravasation of 220% (P less than 0.05) in the trachea, with the greatest effect at a dose of 100 ng/kg (858%; P less than 0.01). Histamine (150 micrograms/kg iv) caused a 320% increase over base line in the trachea and 200% in main bronchi; this effect was equivalent to that induced by 10 ng/kg PAF in the trachea and 1 ng/kg in main bronchi. The duration of effect of PAF was greatest in main bronchi (less than 10 min). Platelet depletion with a cytotoxic antibody, or the cyclooxygenase inhibitor, indomethacin, or the cyclooxygenase-lipoxygenase inhibitor, BW 7556, did not affect the vascular permeability response to PAF. The PAF-receptor antagonist, BN 52063, inhibited Evans blue extravasation in the airways in a dose-dependent manner, with complete inhibition at 5 mg/kg. Thus PAF-induced airway vascular leakage is mediated by specific receptors but not by products of arachidonic acid metabolism or by platelets. Increased airway microvascular leakage induced by PAF may lead to plasma extravasation and airway edema, factors that may contribute to the airway narrowing and hyperresponsiveness induced by PAF.

Our aim was to demonstrate increased NO activity from inducible NO synthase (iNOS) in pulmonary arteries (PA) from rats treated with endotoxin [lipopolysaccharide (LPS), 20 mg/kg ip]. LPS treatment diminished the contractile response of PA to potassium chloride (KCl) and phenylephrine (PE) and increased levels of guanosine 3',5'-cyclic monophosphate (cGMP) in endothelium-denuded vessels. Both the NO synthase (NOS) antagonists NG-monomethyl-L-arginine (L-NMMA; nonselective) and aminoguanidine (selective for iNOS) enhanced PE-induced contraction in endothelium-denuded vessels from LPS-treated rats. Furthermore, L-NMMA-induced contraction of endothelium-denuded vessels from LPS-treated rats was stereospecifically antagonized by L-arginine and associated with decreased cGMP levels. These data suggest that NO is produced in increased amounts from PA smooth muscle after LPS treatment. LPS treatment caused increased expression of mRNA for iNOS in PA. This effect of LPS was attenuated by pretreatment with dexamethasone, suggesting that induction of NOS in PA smooth muscle underlies the increased NO activity associated with LPS administration.