Maternal and procedural factors associated with estimated blood loss in second trimester surgical uterine evacuation: a retrospective cohort analysis.

BACKGROUND: Prior studies examining bleeding with uterine evacuation have focused on high-volume centers performing over 1100 procedures annually. The aim of this study was to examine associations between blood loss and patient and procedural characteristics in a center performing fewer than 50 procedures annually. METHODS: This retrospective cohort study, with institutional review board approval, utilized procedural codes to identify patients undergoing uterine evacuation procedures between 14 weeks' and 24 weeks' gestational age across a 50-month period. The primary outcome was estimated blood loss; secondary outcomes were hemorrhage, transfusion and hospital re-admission. Associations between blood loss and other variables were examined using linear regression models. RESULTS: Charts of 161 women met inclusion criteria. Median estimated blood loss was 400 mL (IQR 300 mL) with 37% of patients having blood loss of ≥500 mL. In univariate analyses, increased blood loss was associated with later gestational age (P <0.001) and pregnancy termination (P <0.001). In a multiple linear regression model, both remained significant. Each one-week increase in gestational age was associated with a 7.1% mean increase in estimated blood loss (95% CI 2.47% to 11.9%; P=0.003). Patients whose uterine evacuation was indicated for pregnancy termination had an 80.6% increase in blood loss compared with those with pre-operative fetal demise (95% CI 37.5% to 137.2%; P <0.001). Rates of peri-operative transfusion and re-admission for bleeding were <4%. CONCLUSION: While blood loss may be greater in low volume centers, our transfusion and re-admission rates were low following second trimester uterine evacuation.

Influence of decreasing nutrient path length on the development of engineered cartilage.

OBJECTIVE: Chondrocyte-seeded agarose constructs of 4mm diameter (2.34 mm thickness) develop spatially inhomogeneous material properties with stiffer outer edges and a softer central core suggesting nutrient diffusion limitations to the central construct region [Guilak F, Sah RL, Setton LA. Physical regulation of cartilage metabolism. In: Mow VC, Hayes WC, Eds. Basic Orthopaedic Biomechanics, Philadelphia 1997;179-207.]. The effects of reducing construct thickness and creating channels running through the depth of the thick constructs were examined. METHODS: In Study 1, the properties of engineered cartilage of 0.78 mm (thin) or 2.34 mm (thick) thickness were compared. In Study 2, a single nutrient channel (1 mm diameter) was created in the middle of each thick construct. In Study 3, the effects of channels on larger 10 mm diameter, thick constructs were examined. RESULTS: Thin constructs developed superior mechanical and biochemical properties than thick constructs. The channeled constructs developed significantly higher mechanical properties vs control channel-free constructs while exhibiting similar glycosaminoglycan (GAG) and collagen content. Collagen staining suggested that channels resulted in a more uniform fibrillar network. Improvements in constructs of 10 mm diameter were similarly observed. CONCLUSIONS: This study demonstrated that more homogeneous tissue-engineered cartilage constructs with improved mechanical properties can be achieved by reducing their thickness or incorporating macroscopic nutrient channels. Our data further suggests that these macroscopic channels remain open long enough to promote this enhanced tissue development while exhibiting the potential to refill with cell elaborated matrix with additional culture time. Together with reports that <3 mm defects in cartilage heal in vivo and that irregular holes are associated with clinically used osteochondral graft procedures, we anticipate that a strategy of incorporating macroscopic channels may aid the development of clinically relevant engineered cartilage with functional properties.

Mechanical and biochemical characterization of cartilage explants in serum-free culture.

Allografts of articular cartilage are both used clinically for tissue-transplantation procedures and experimentally as model systems to study the physiological behavior of chondrocytes in their native extracellular matrix. Long-term maintenance of allograft tissue is challenging. Chemical mediators in poorly defined culture media can stimulate cells to quickly degrade their surrounding extracellular matrix. This is particularly true of juvenile cartilage which is generally more responsive to chemical stimuli than mature tissue. By carefully modulating the culture media, however, it may be possible to preserve allograft tissue over the long-term while maintaining its original mechanical and biochemical properties. In this study juvenile bovine cartilage explants (both chondral and osteochondral) were cultured in both chemically defined medium and serum-supplemented medium for up to 6 weeks. The mechanical properties and biochemical content of explants cultured in chemically defined medium were enhanced after 2 weeks in culture and thereafter remained stable with no loss of cell viability. In contrast, the mechanical properties of explants in serum-supplemented medium were degraded by ( approximately 70%) along with a concurrent loss of biochemical content (30-40% GAG). These results suggest that long-term maintenance of allografts can be extended significantly by the use of a chemically defined medium.

Identification of clinical isolates of nondiphtherial Corynebacterium species and their antibiotic susceptibility patterns.

Starting in 1982, our laboratory has performed species identification of coryneform bacteria isolated from blood cultures, intravenous (i.v.) catheter tips and sites, urines with high colony counts, and other potentially significant cultures, using predefined criteria. Of 283 isolates identified, Corynebacterium jeikeium was the most common (47%), followed by CDC group G2 (12%) and C. minutissimum (8%). Blood cultures and i.v. catheter-related sources were the most frequent sources (58% of total). Certain species or groups, like CDC group G2, were most frequently isolated from blood or i.v. catheter sites. CDC group G2 showed a progression to greater multiple antibiotic resistance during this 9-year period. Occasional multiresistant strains of other species were also encountered. By in vitro testing, we note vancomycin remains the most active agent against corynebacterialike organisms, and is the most reliable antibiotic to use while awaiting susceptibility testing results.

Clinical and microbiological observations on CDC group DF-3, a gram-negative coccobacillus.

Sequential stool cultures submitted for routine culture were screened for the presence of CDC group DF-3. Of 690 specimens, 11 (1.6%) yielded moderate to heavy growth of DF-3. Information on the 11 patients from whom these specimens were obtained showed that 4 had a history of prolonged diarrheal disease that resolved after specific therapy to eradicate DF-3, while for the other 7 patients no clear role could be established. Microbiological characterization of the stool isolates and 10 CDC strains of DF-3 suggested the presence of two subtypes within the group. Antibiotic susceptibility studies showed DF-3 to be relatively resistant to a wide variety of antibiotics.

Colonization of newly arrived house staff by virulent staphylococcal phage types endemic to a hospital environment.

The acquisition of hospital strains of Staphylococcus aureus by new house officers was studied in an 800-bed referral hospital over a 1-year period. S. aureus isolates, including three strains with characteristic phage patterns that had previously been documented to cause disease in patients and colonize hospital personnel, were recovered from the anterior nares of 35 of 54 newly arrived house officers. There was a significant correlation (r = 0.7475; P less than 0.02) between colonization with the dominant hospital strain (S) and exposure to the hospital environment over 12 months. No hospital-wide increase in infections owing to the S strain was seen during this period, which suggests that house staff acquired this strain from reservoirs within the hospital. The finding of colonization with virulent endemic S. aureus strains in house officers working on every ward of the hospital suggests that new strategies for control of S. aureus nosocomial infections must be considered and evaluated.