Deciding on route of delivery for obese women with a prior cesarean delivery.

OBJECTIVES: This study was undertaken to estimate the vaginal birth after cesarean (VBAC) success rate, compare rates of infections in women attempting VBAC and those undergoing planned repeat cesarean, and compare the cost of these two plans of care for obese women. STUDY DESIGN: We performed a historical cohort analysis of singleton deliveries at >/=36 weeks' gestation in women with a body mass index 40 or greater and one prior cesarean delivery. Outcomes included rates of VBAC success and puerperal infections and mean cost of care. RESULTS: The cohort consisted of 122 mother-infant pairs, 61 each in the VBAC and cesarean groups. In the VBAC group, 57% (95% CI 45-70) of women were delivered vaginally. The VBAC group had higher rates of chorioamnionitis (13.1% vs 1.6%, P=.02), endometritis (6.6% vs 0%, P=.06), and composite puerperal infection (24.6% vs 8.2%, P=.01). Mean cost of care was similar for mothers ($4439 vs $4427, P=.95), infants ($1241 vs $1422, P=.49), and mother-infant pairs ($5680 vs $5851, P=.64). CONCLUSION: Compared with planned cesarean delivery, VBAC trials in obese women are three times as likely to be complicated by infection and do not result in reduced costs.

Vaginal birth after cesarean delivery: an historic cohort cost analysis.

OBJECTIVE: The purpose of this study was to evaluate the relative cost-effectiveness of attempted vaginal birth after cesarean delivery compared with elective repeat cesarean delivery. STUDY DESIGN: We performed an historic cohort analysis of women with a single prior cesarean delivery who were delivered at our institution during 1999. Inclusion criteria were > or =36 weeks' gestation and carrying a live, singleton fetus with no antenatally diagnosed anomalies. The primary outcome variable was mean cost of hospital care for mother-infant pairs, as obtained from the hospital's Clinical Resources Department. RESULTS: The cohort consisted of 204 mother-infant pairs, 65 in the elective repeat cesarean group and 139 in the attempted vaginal birth group. Mean cost of care was higher for mothers ($4155 vs $3675;P <.001), neonates ($1794 vs $1187; P =.03), and mother-infant pairs ($5949 vs $4863; P =.001) for the elective repeat cesarean group compared with the attempted vaginal delivery group. CONCLUSION: In women with a single prior cesarean delivery, a trial of labor is more cost-effective than an elective repeat cesarean delivery.

A continuous culture biofilm model of cariogenic responses.

AIMS: To validate an in vitro model for the analysis of physiological and ecological responses to sugar challenge in bacterial populations, and subsequent changes in enamel mineralization. METHODS AND RESULTS: A seven-organism bacterial consortium was grown in a biofilm mode on enamel and hydroxyapatite (HA) surfaces in a continuous culture system and exposed to repeated sucrose challenges. This produced 'pH-cycling' conditions within the system. Populations on HA surfaces were enumerated. Changes in relative proportions of the different populations, and in the total viable count, were observed, between different treatments. Microradiography of the enamel sections showed increasing demineralization with increasing sucrose concentration. The lesions formed were similar to 'white-spot' lesions found in vivo. Differences in the quality of biofilms formed were also observed using Confocal Laser Scanning Microscopy. CONCLUSION: An in vitro model has been validated for the analysis of both physiological and ecological responses to sucrose challenges in bacterial populations, and subsequent changes in enamel mineralization. SIGNIFICANCE AND IMPACT OF THE STUDY: This model should facilitate the study of changes in bacterial populations in response to application of putative anticaries agents and concomitant changes in enamel mineralization.

Methods for microscopic characterization of oral biofilms: analysis of colonization, microstructure, and molecular transport phenomena.

Assessment of the role of biofilm microstructure in biofilm-specific activities requires non-destructive measurement techniques for parameterization of structural characteristics in parallel with relevant biochemical and physiological data. This paper briefly reviews some current methods for biofilm structural analysis, with emphasis on new developments in optical imaging and mathematical modeling methods. Fluorescence imaging studies of bacterial colonization events occurring on exposed model tooth surfaces indicated that bacterial adhesion to sessile organisms was of central importance to the early colonization process and that this occurred in a non-random manner. Structural studies of mature biofilms by confocal microscopy demonstrated the spatial distribution of individual species using fluorescent antibodies. Biofilms grown under different physiological conditions exhibited differences in structure, and methods were developed for parameterizing the spatial orientations of the bacteria. Diffusive processes within biofilm microstructures were studied using a random walk model in both 2-D and 3-D. Modeling of convective flow within biofilm microstructures was achieved by application of lattice Boltzmann methodology.

Computerized pre-anesthetic evaluation results in additional abstracted comorbidity diagnoses.

OBJECTIVE: To study the impact of information from a physician-entry computerized preanesthetic evaluation system on the coding of International Classification of Diseases (ICD-9-CM) diagnoses and on hospital reimbursement due to alterations in diagnosis-related group (DRG) codes. METHODS: Nonrandomized, unblinded trial conducted at a 570-bed university tertiary care hospital. First without and then with reference to information contained on computer-based preanesthetic evaluation reports, medical charts were coded by the study institution's usual professional codes for ICD-9-CM discharge diagnoses and DRG assignment. RESULTS: For 22 of 180 charts studied (12%, 95% confidence limits 7.4% to 16.7%), at least one ICD-9-CM diagnosis was added. Three of 84 DRG-based reimbursements were altered, increasing hospital reimbursement by 1.5%. CONCLUSIONS: Supplemental information from a physician-entered, problem-oriented, computerized preanesthetic evaluation system improved discovery of diagnoses in the population studied.

Diffusion and binding measurements within oral biofilms using fluorescence photobleaching recovery methods.

Numerous studies have postulated that bacteria which reside in a biofilm differ from planktonic bacteria. These differences are thought to affect biofilm permeability and, indirectly, the susceptibility of biofilm bacteria to antibacterial agents. In this study fluorescence recovery after photobleaching (FRAP) was used to monitor the diffusion and binding characteristics of a set of size fractionated fluorescein isothiocyanate (FTTC)-conjugated dextrans over small areas (ca. 10 micron) in bacterial biofilms. From these measurements it was straightforward to calculate apparent diffusion rates. Initial studies on the concentration dependence of dextran interaction with planktonic bacteria showed that no irreversible interaction was occurring, however, anomalous faster than free solution diffusion rates were obtained. This phenomenon was modelled using novel analytical and numerical methods which incorporate reversible binding with associated fluorescence changes. Apparent diffusion rates measured in biofilms were highly dependent on biofilm preparation. Sucrose starved biofilms produced an apparent slow-down of two- to fivefold depending on dextran molecular mass and location within the biofilm, indicating that diffusion within the biofilm is hindered. Sucrose supplemented biofilms produced apparent diffusion rates close to those in free solution, suggesting less hindered diffusion. Ex vivo plaque showed diffusion and binding similar to the sucrose supplemented biofilms. The FRAP approach provides a fast and convenient method for determining diffusion rates over small areas within bacterial biofilms. This study reinforces the importance of considering the influence of reversible binding and associated fluorescence changes, as these may have a marked effect on the measured apparent diffusion rate.