Efficacy of IV theophylline in children with severe status asthmaticus.

STUDY OBJECTIVE: To determine whether adding IV theophylline to an aggressive regimen of inhaled and IV beta-agonists, inhaled ipratropium, and IV methylprednisolone would enhance the recovery of children with severe status asthmaticus admitted to the pediatric ICU (PICU). DESIGN: A prospective, randomized, controlled trial. Asthma scoring was performed by investigators not involved in treatment decisions and blinded to group assignment. SETTING: The PICU of an urban, university-affiliated, tertiary-care children's hospital. PATIENTS: Children with a diagnosis of status asthmaticus who were admitted to the PICU for < or = 2 h and who were in severe distress, as indicated by a modified Wood-Downes clinical asthma score (CAS) of > or = 5. INTERVENTIONS: All subjects initially received continuous albuterol nebulizations; intermittent, inhaled ipratropium; and IV methylprednisolone. The theophylline group was also administered infusions of IV theophylline to achieve serum concentrations of 12 to 17 microg/mL. A CAS was tabulated twice daily. MEASUREMENTS AND RESULTS: Forty-seven children (median age, 8.3 years; range, 13 months to 17 years) completed the study. Twenty-three children received theophylline. The baseline CASs of both groups were similar and included three subjects receiving mechanical ventilation in each group. All subjects receiving mechanical ventilation and theophylline were intubated before drug infusion. Among the 41 subjects who were not receiving mechanical ventilation, those receiving theophylline achieved a CAS of < or = 3 sooner than control subjects (18.6 +/- 2.7 h vs 31.1 +/- 4.5 h; p < 0.05). Theophylline had no effect on the length of PICU stay or the total incidence of side effects. Subjects receiving theophylline had more emesis (p < 0.05), and control patients had more tremor (p < 0.05). CONCLUSIONS: Theophylline safely hastened the recovery of children in severe status asthmaticus who were also receiving albuterol, ipratropium, and methylprednisolone. The role of theophylline in the management of asthmatic children in impending respiratory failure should be reexamined.

Modified RIFLE criteria in critically ill children with acute kidney injury.

A classification system has been proposed to standardize the definition of acute kidney injury in adults. These criteria of risk, injury, failure, loss, and end-stage renal disease were given the acronym of RIFLE. We have modified the criteria based on 150 critically ill pediatric RIFLE (pRIFLE) patients to assess acute kidney injury incidence and course along with renal and/or non-renal comorbidities. Of these children, 11 required dialysis and 24 died. Patients without acute kidney injury in the first week of intensive care admission were less likely to subsequently develop renal Injury or Failure; however, 82% of acute kidney injury occurred in this initial week. Within this group of 123 children, 60 reached pRIFLEmax for Risk, 32 reached Injury, and 31 reached Failure. Acute kidney injury during admission was an independent predictor of intensive care; hospital length of stay and an increased risk of death independent of the Pediatric Risk of Mortality (PRISM II) score (odds ratio 3.0). Our results show that a majority of critically ill children develop acute kidney injury by pRIFLE criteria and do so early in the course of intensive care. Acute kidney injury is associated with mortality and may lead to increased hospital costs. We suggest that the pRIFLE criteria serves to characterize the pattern of acute kidney injury in critically ill children.

Differential effects of pentoxifylline and interleukin-10 on production of tumor necrosis factor and inducible nitric oxide synthase by murine macrophages.

The abilities of pentoxifylline and recombinant interleukin-10 (rIL-10) to inhibit tumor necrosis factor (TNF) and inducible nitric oxide synthase (iNOS) production in RAW 264.7 murine macrophages were compared. Pentoxifylline consistently inhibited the accumulation of both TNF and iNOS in a dose-dependent manner whether the stimulus was bacterial lipopolysaccharide (LPS), recombinant interferon-gamma (rIFN-gamma), or LPS plus rIFN-gamma. Similarly, rIL-10 consistently reduced TNF production by cells stimulated with LPS, rIFN-gamma, or LPS plus rIFN-gamma. However, rIL-10 weakly inhibited LPS-induced iNOS production but failed to block (and often augmented) rIFN-gamma-induced iNOS production. Combinations of pentoxifylline and rIL-10 led to additive or synergistic inhibition of TNF but not iNOS production; in fact, rIL-10 appeared to interfere with the ability of pentoxifylline to block iNOS accumulation. These data suggest that combinations of antiinflammatory agents may have unanticipated effects on inflammatory mediator production.

Brief hypoxic stress suppresses postbacteremic NF-kappaB activation and TNF-alpha bioactivity in perfused liver.

Reductions in hepatic O(2) delivery are common early after gram-negative bacteremic sepsis owing to cardiopulmonary dysfunction and derangements in sinusoidal perfusion. Although gram-negative endotoxin and cellular hypoxia independently enhance activation of nuclear factor-kappaB (NF-kappaB) via generation of reactive O(2) species (ROS), the combination of these stimuli downregulates hepatic TNF-alpha gene expression. Here we tested the hypothesis that hypoxic suppression of postbacteremic TNF-alpha gene expression is transcriptionally mediated by reduced activation of NF-kappaB. Buffer-perfused rat livers (n = 52) were studied over 180 min after intraportal infection at t = 0 with 10(9) live Escherichia coli (EC), serotype O55:B5, or 0.9% NaCl controls under normoxic conditions, compared with 0.5 h of constant-flow hypoxia (PO(2) approximately 41 +/- 7 Torr) beginning at t = 30 min, followed by 120 min of reoxygenation. In parallel studies, tissue was obtained at peak hypoxia (t = 60 min). To determine the role of xanthine oxidase (XO)-induced ROS in modulating NF-kappaB activity after hypoxia/reoxygenation (H/R), livers were pretreated with the XO inhibitor allopurinol, with results confirmed in organs of tungstate-fed animals. Electrophoretic mobility shift assays were performed on nuclear extracts of whole liver lysates using (32)P-labeled oligonucleotides specific for NF-kappaB. Compared with normoxic EC controls, hypoxia reduced postbacteremic NF-kappaB nuclear translocation and TNF-alpha bioactivity, independent of reoxygenation, tissue levels of reduced glutathione, or posthypoxic O(2) consumption. XO inhibition reversed the hypoxic suppression of NF-kappaB nuclear translocation and ameliorated decreases in cell-associated TNF-alpha. Thus decreases in hepatic O(2) delivery reduce postbacteremic nuclear translocation of NF-kappaB and hepatic TNF-alpha biosynthesis by signaling mechanisms involving low-level generation of XO-mediated ROS.