Internally coated endotracheal tubes with silver sulfadiazine in polyurethane to prevent bacterial colonization: a clinical trial.

OBJECTIVE: Coated medical devices have been shown to reduce catheter-related infections. We coated endotracheal tubes (ETT) with silver sulfadiazine (SSD), and tested them in a clinical study to assess the feasibility, safety, and efficacy of preventing bacterial colonization. DESIGN: A prospective, randomized clinical trial, phase I-II. SETTING: Academic intensive care unit (ICU). PARTICIPANTS: Forty-six adult patients expected to need 12-24 h of intubation were randomized into two groups. INTERVENTIONS: Patients were randomized to be intubated with a standard non-coated ETT (St-ETT, n=23; control group), or with a SSD-coated ETT (SSD-ETT, n=23). MEASUREMENTS AND RESULTS: Coating with SSD prevented bacterial colonization of the ETT (frequency of colonization: SSD-ETT 0/23, St-ETT 8/23; p<0.01). No organized bacterial biofilm could be identified on the lumen of any ETT; however, SSD was associated with a thinner mucus layer (in the SSD-ETT secretion deposits ranged from 0 to 200 microm; in the St-ETT deposits ranged between 50 and 700 microm). No difference was observed between the two groups in the tracheobronchial brush samples (frequency of colonization: SSD-ETT 0/23, St-ETT 2/23; p=0.48). No adverse reactions were observed with the implementation of the novel device. CONCLUSION: SSD-ETT can be safely used in preventing bacterial colonization and narrowing of the ETT in patients intubated for up to 24 h (mean intubation time 16 h).

Rheological properties, biocompatibility and in vivo performance of new hydrogel-based bone fillers.

Three different heterologous substitutes for bone regeneration, manufactured with equine-derived cortical powder (CP), cancellous chips (CC) and demineralized bone matrix granules (DBM), were compared in in vitro and in vivo settings. We tested: a commercially available bone paste (Osteoplant-Activagen™, consisting of aqueous collagenous carrier, CP, DBM; named A); a second-generation injectable paste (20 kDa polyethylene glycol/hydroxypropyl-methyl cellulose-based hydrogel, CP, DBM; B); a pre-formed bone filler (400 kDa polyethylene oxide/hydroxypropyl-methyl cellulose-based hydrogel, CP, CC, DBM; C). Vitamin C acted as a visco-modulator during C and B ß-rays sterilization, modifying graft injectability. For each filler, we examined dissolution in culture medium, gene expression of the substitute-exposed osteogenically-induced human bone marrow stromal cells (hBMSC), and performance in a rabbit bone defect model. A dissolved after 1 h, while fragmentation of B peaked after 8 h. C remained unaltered for 2 days, but affected the microenvironmental pH, slowing the proliferation of exposed cells. B-exposed hBMSC overexpressed bone sialoprotein, osteocalcin and RUNX2. For all fillers histological results evidenced bridged lesion margins, marrow replenishment and bone-remodeling. However, B-treated lesions displayed a metachromatic type II collagen-rich matrix with prehypertrophic-like cells, matching the in vitro expression of cartilage-specific markers, and suggesting a possible application of B/C double-layer monolithic osteochondral plugs for full-thickness articular defects.