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Biomedical subjects

P D Levin

Publications and source records attributed to P D Levin.

13 recordsLinked to original sources
PubMed2000

The use of the arterial line as a source for blood cultures.

OBJECTIVE: To determine the reliability of blood cultures obtained through indwelling arterial lines as compared to that of blood cultures obtained by venipuncture. DESIGN: A prospective observational study. SETTING: Six-bed mixed medical surgical intensive care unit (ICU) of a 550-bed university-affiliated medical center. MEASUREMENTS: During a 3-month period blood culture sets, when clinically indicated, were drawn in parallel from indwelling arterial catheters and one-time venipuncture and the results compared. Each blood sample consisted of 15 ml and was distributed equally between three blood culture bottles: aerobic, anaerobic and one aerobic resin-containing bottle. Blood culture results from the two sources were compared according to preset definitions. MAIN RESULTS: During the study period 90 parallel blood culture sets (540 bottles) were obtained from 36 patients. Forty-three (16%) venipuncture bottles were positive versus 88 (32%) arterial line culture bottles (p < 0.001). Of the parallel sets, 83% yielded equivalent results - either both sterile or both growing the same organism. Amongst the discordant sets, the arterial line cultures grew 37 gram-positive and 18 gram-negative isolates not found in venipuncture sets (i.e. 50% of 109 arterial line isolates), while only two gram-positive isolates were solely grown in venipuncture cultures (4% of all 55 venipuncture isolates, p < 0.001). On clinical correlation, all the gram-positive organisms in the discordant cultures were found not to reflect bacteremia, while five of the 18 gram-negative isolates (28%) grown only in arterial line cultures probably did reflect ongoing bacteremia. CONCLUSION: The results of blood cultures taken from the arterial line are frequently equivalent to those taken from venipuncture. When discordant, the growth of gram-positive bacteria almost certainly reflects contamination or arterial line colonization, whereas the growth of gram-negative bacteria may have to be considered as reflecting bacteremia.

Bacteremia↗
PubMed1997

Routine surveillance blood cultures: their place in the management of critically ill patients.

The use of surveillance blood cultures has been advocated as a means to allow earlier detection of septic episodes amongst intensive care patients, and therefore earlier institution of appropriate antibiotic therapy. We compared the results of surveillance cultures and clinically indicated blood cultures for bacterial isolates grown and the influence of culture results on patient management. Blood cultures were obtained from all intensive care unit (ICU) patients over the course of 3 months at a set surveillance time (surveillance group) or according to clinical indications (clinical group). Bacteriological results were compared and real-time chart review performed to assess the influence of the surveillance cultures on patient management, with particular reference to antibiotic therapy. Two hundred and forty-nine blood culture sets were collected over 3 months, 99 in the surveillance group and 150 in the clinical group. A total of 256 bacterial isolates were grown, 95 in the surveillance group and 161 in the clinical group. For the surveillance group 36%, 20%, and 44% of the isolates represented bacteraemia, line colonization and culture contamination, respectively. For the clinical group the distibution was 69%, 7%, and 24% respectively (P<0.001, P<0.01, and P<0.0027 for comparisons of percentages within each classification). On only one occasion was antibiotic therapy started based on the result of a surveillance culture, and on only one occasion was a septic episode detected earlier by a surveillance culture; however, this culture result did not lead to a change in patient management. Surveillance blood cultures are expensive and add very little to the management of patients in the intensive care environment.

Adult↗
PubMed1996

Impact of the resin blood culture medium on the treatment of critically ill patients.

OBJECTIVE: To assess the relevance, both clinical and bacteriologic, of the use of resin-containing blood culture media in blood cultures taken from critically ill patients receiving antibiotics. DESIGN: A prospective, open clinical trial. SETTING: The mixed medical surgical intensive care unit (ICU) of a 550-bed urban hospital. PATIENTS: All ICU patients admitted during a 3-month period (n = 49) with suspected sepsis requiring blood cultures as part of their laboratory investigations. INTERVENTIONS: The use of an aerobic resin-containing blood culture medium, in addition to the regular aerobic and anaerobic media for all blood cultures taken. MEASUREMENTS AND MAIN RESULTS: Each blood culture result was classified as to its clinical significance. Changes in patient management were recorded. Culture sets in which the resin-containing bottle provided the information central to the change in patient management were identified. Bacteriologically, the results from the resin-containing medium were compared with the results from the aerobic and anaerobic media. Of 266 blood culture sets, 103 (39%) were positive, growing 278 bacterial and fungal isolates. Clinically, the resin-containing medium alone provided relevant data leading to changes in patient management on three occasions. On two of these occasions, cultures from the regular media provided the same data within 72 hrs. Bacteriologically, 77 (29%) aerobic bottles, 55 (21%) anaerobic bottles, and 89 (33%) resin-containing bottles were positive (statistical comparison of percentages: aerobic vs. resin-containing bottles, nonsignificant; aerobic vs anaerobic bottles, p < .046; anaerobic vs. resin-containing bottles, p < .0027). A similar proportion of pathogens was isolated from the resin-containing bottles only (9%) and aerobic bottles only (6%). A higher proportion of contaminants was isolated from the resin-containing bottles only than the aerobic bottles only in the various sets (17% vs. 7%, p < .046). The resin-containing bottle showed a trend toward increased detection of Staphylococcus aureus and Pseudomonas aeruginosa bacteremia. CONCLUSIONS: The resin-containing medium offers little clinical benefit to the majority of ICU patients. Bacteriologically, it seems to have a similar overall sensitivity as the regular aerobic medium (with the possible exception of a higher sensitivity for the isolation of S. aureus and P. aeruginosa), but a lower specificity. The wide-spread use of the resin-containing bottle cannot be recommended.

Anti-Bacterial Agents↗
PubMed1987

Functional consequences of embryonic neocortex transplanted to rats with prefrontal cortex lesions.

In four experiments we reexamined the recent report by Labbe, Firl, Mufson, and Stein (1983) that fetal cortical tissue transplanted to an aspirative prefrontal cortical cavity in rats can ameliorate the learning impairments induced by the aspirative lesions. Healthy surviving grafts from young (E16) embryonic donors had no immediate effects on the rats' impairments in T-maze alternation, spatial navigation in the Morris swimming pool task, or locomotor activity, and they produced even greater impairments than the lesions alone when all three tests were conducted after longer (3-5 month) survival periods. Grafts taken from older (E21) donors did produce a short-lasting improvement in the T-maze alternation performance, replicating the previous report. However, this effect was not seen in the other two behavioral tests; the grafts survived poorly, and the beneficial effect was no longer apparent in the long-term tests. It is concluded that (a) functional benefits of embryonic cortical grafts are dependent on a precise combination of conditions rather than being a general phenomenon, and (b) the short-lasting recovery in delayed alternation performance is attributable to diffuse influences of the embryonic tissue on the lesioned host brain rather than to a reconnection of damaged circuitries.

Animals↗
PubMed1975

The effectiveness of various antibiotics in methyl methacrylate.

The effectiveness of different antibiotics mixed with Simplex P has been tested in vitro. A laboratory model was designed to simulate the constant immersion of bone cement in tissue fluid. Clindamycin, and to a lesser extent Cephalothin, were shown to be effective when used in this manner against Staphylococcus aureus and epidermidis. Effective inhibition of Gram-negative organisms could not be demonstrated with any of the antibiotics tested. The addition of up to 3 grams of antibiotic powder per unit of 40 grams of Simplex P did not appear to alter the expansive properties of the cement. Such release of antibiotics as did occur was thought to be related to the slow absorption of water by the slightly porous methyl methacrylate.

Anti-Bacterial Agents↗
PubMedDate not supplied

Reconstruction of the patellar tendon using a dacron graft: a case report.

A case is presented in which a patellar tendon has undergone shortening and degeneration after rupture of a primary repair. The extensor tendon mechanism was reconstructed by using a dacron graft to substitute for the missing patellar tendon and follow-up at 15 months post-surgery showed excellent return of function. Factors in the successful outcome were thought to be both the intrinsic strength of the dacron graft and the ability of fibroblasts to infiltrate the dacron mesh to form a new tendon-like structure.

Adult↗