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Biomedical subjects

Marcus J Schultz

Publications and source records attributed to Marcus J Schultz.

At least 55 records · Page 3Linked to original sources
PubMed2005

Alveolar fibrinolytic capacity suppressed by injurious mechanical ventilation.

OBJECTIVE: To investigate the effect of mechanical ventilation on alveolar fibrinolytic capacity. DESIGN AND SETTING: Randomized controlled animal study in 66 Sprague-Dawley rats. SUBJECTS AND INTERVENTIONS: Test animals received intratracheal fibrinogen and thrombin instillations; six were killed immediately (fibrin controls), and the others were allocated to three ventilation groups (ventilation period: 225 min) differing in positive inspiratory pressure and positive end-expiratory pressure, respectively: group 1, 16 cmH2O and 5 cmH2O (n=17); group 2, 26 cmH2O and 5 cmH2O (n=16); group 3, 35 cmH2O and of 5 cmH2O (n=17). Ten animals that had not been ventilated served as healthy controls. MEASUREMENTS AND RESULTS: After animals were killed, we measured D-dimers, plasminogen activator inhibitor (PAI) 1, and tumor necrosis factor alpha in the bronchoalveolar lavage fluid and calculated lung weight and pressure/volume (P/V) plots. The median D-dimer concentration (mg/l) decreased with increasing pressure amplitude (192 in group 1, IQR 119; 66 in group 2, IQR 107; 29 in group 3, IQR 30) while median PAI-1 (U/ml) increased (undetectable in group 1; 0.55 in group 2, IQR 4.55; 3.05 in group 3, IQR 4.85). PAI-1 level was correlated with increased lung weight per bodyweight (Spearman's rank correlation 0.708). Tumor necrosis factor alpha concentration was not correlated with PAI-1 level. CONCLUSIONS: Alveolar fibrinolytic capacity is suppressed during mechanical ventilation with high pressure amplitudes due to local production of PAI-1.

Analysis of Variance↗
PubMed2005

Feedback and education improve physician compliance in use of lung-protective mechanical ventilation.

OBJECTIVE: Use of lung-protective mechanical ventilation (MV) by applying lower tidal volumes is recommended in patients suffering from acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). Recent data suggest that lung-protective MV may benefit non-ALI/ARDS patients as well. This study analyzed tidal volume settings in three ICUs in The Netherlands to determine the effect of feedback and education concerning use of lung-protective MV. DESIGN AND SETTING: Observational study in one academic and two nonacademic "closed format" ICUs. PATIENTS: Intubated mechanically ventilated subjects. INTERVENTIONS: Feedback and education concerning lung-protective MV with special attention to the importance of closely adjusting tidal volumes to predicted body weight (PBW). RESULTS: Tidal volumes declined significantly within 6 months after intervention (from 9.8+/-2.0 at baseline to 8.1+/-1.7 ml/kg PBW) as the percentage of undesirable ventilation data points, defined as tidal volumes greater than 8 ml/kg PBW (84% vs. 48%). There were no differences between patients meeting the international definition criteria for ALI/ARDS and those not. Only four patients received tidal volumes less than 6 ml/kg PBW. Lower tidal volumes were still used after 12 months. Tidal volumes in patients on mandatory MV and patients breathing on spontaneous modes were similar. CONCLUSIONS: Feedback and education improve physician compliance in use of lung-protective MV.

Aged↗
PubMed2005

Bench-to-bedside review: preventive measures for contrast-induced nephropathy in critically ill patients.

An increasing number of diagnostic imaging procedures requires the use of intravenous radiographic contrast agents, which has led to a parallel increase in the incidence of contrast-induced nephropathy. Risk factors for development of contrast-induced nephropathy include pre-existing renal dysfunction (especially diabetic nephropathy and multiple myeloma-associated nephropathy), dehydration, congestive heart failure and use of concurrent nephrotoxic medication (including aminoglycosides and amphotericin B). Because contrast-induced nephropathy accounts for a significant increase in hospital-acquired renal failure, several strategies to prevent contrast-induced nephropathy are currently advocated, including use of alternative imaging techniques (for which contrast media are not needed), use of (the lowest possible amount of) iso-osmolar or low-osmolar contrast agents (instead of high-osmolar contrast agents), hyperhydration and forced diuresis. Administration of N-acetylcysteine, theophylline, or fenoldopam, sodium bicarbonate infusion, and periprocedural haemofiltration/haemodialysis have been investigated as preventive measures in recent years. This review addresses the literature on these newer strategies. Since only one (nonrandomized) study has been performed in intensive care unit patients, at present it is difficult to draw firm conclusions about preventive measures for contrast-induced nephropathy in the critically ill. Further studies are needed to determine the true role of these preventive measures in this group of patients who are at risk for contrast-induced nephropathy. Based on the available evidence, we advise administration of N-acetylcysteine, preferentially orally, or theophylline intravenously, next to hydration with bicarbonate solutions.

Acetylcysteine↗
PubMed2005

Struggle for implementation of new strategies in intensive care medicine: anticoagulation, insulin, and lower tidal volumes.

The management of intensive care patients have changed dramatically in the last years: from merely supportive care, it has moved to evidence-based strategies that have been demonstrated to reduce mortality of the severely ill patients. Clinical research have brought numerous positive clinical trials offering intensive care physicians specific therapies to improve outcome of intensive care patients. Among them were the trials that tested the infusion of activated protein C in patients with severe sepsis, tight glycemic control in surgical intensive care patients, and use of lung protective mechanical ventilation by using small tidal volumes in patients with acute lung injury. Although results of these trials were sufficiently strong to, at least, consider implementation of these strategies in critical care medicine, published and yet unpublished reports show that there is significant struggle with implementation of these therapies. This manuscript focuses on the potential reasons that underlie this problem.

Anticoagulants↗
PubMed2005

Pneumonia models and innate immunity to respiratory bacterial pathogens.

Preclinical sepsis models have been used for decades to study the pathophysiologic processes during sepsis and shock. Although these studies revealed promising immunomodulating agents for the treatment of sepsis, clinical trials evaluating the efficacy of these new agents in patients with sepsis were disappointing. The main reason for this unsatisfactory experience might be that unlike the clinical situation, most of these preclinical models are devoid of a localized infectious source from which the infection disseminates. Studies on the effects of several immunomodulating strategies have demonstrated strikingly opposite results when sepsis models with a more natural route of infection, such as pneumonia, were used. In this review, we will give insights into pneumonia models and discuss results and differences in the innate immune responses during distinct pulmonary infection models.

Animals↗
PubMed2004

Case report: a ball valve blood clot in the airways - life-saving whole tube suction.

Respiratory tract obstruction due to a blood clot may result in life threatening ventilatory impairment. Ball valve blood clot obstructions of the airways are rare. A ball valve blood clot acts as a one-way valve, allowing (near) normal air entry into the airways, but (completely) blocking expiration. In a near fatal case of obstruction of the airways by a ball valve blood clot, we performed 'whole tube suction' to resolve the airway problem.

Airway Obstruction↗
PubMed2004

Macrolide activities beyond their antimicrobial effects: macrolides in diffuse panbronchiolitis and cystic fibrosis.

Diffuse panbronchiolitis (DPB) is a pulmonary disease characterized by chronic inflammation of the bronchioles and chronic infiltration of inflammatory cells in the lungs. DPB has several features in common with cystic fibrosis (CF). Clinical trials in patients with DPB or CF suggest a potential role for maintenance (long-term and low-dose) macrolide therapy in the treatment of these chronic pulmonary conditions. Indeed, these studies demonstrate improved clinical and physiological states with macrolide therapy. The beneficial effects of long-term low-dose macrolides are not related to their antimicrobial properties, since levels of macrolides with low-dose treatment are too low to have sufficient antimicrobial effects. Data indicate that macrolides may have immunomodulatory activities: (1) in vitro and ex vivo studies clearly show that macrolides can influence cytokine production by several cell types; (2) furthermore, macrolides can alter polymorphonuclear cell functions in vitro and ex vivo. Although immunomodulation may serve as one explanation for the beneficial effects of macrolides in patients with chronic pulmonary inflammation, the effect of low-dose macrolide therapy on biofilm-formation may form a second explanation for the positive effects of long-term low-dose macrolide therapy. In the present paper, the clinical trials on maintenance macrolide therapy in patients with DPB or CF are reviewed. This is followed by a discussion on the immunomodulating effects of macrolides, and the effects of macrolides on biofilm formation.

Adjuvants, Immunologic↗