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Biomedical subjects

R Platt

Publications and source records attributed to R Platt.

At least 145 records · Page 8Linked to original sources
PubMed1978

Antibiotic irrigation and catheter-associated urinary-tract infections.

To investigate the efficacy of antibiotic irrigation in preventing catheter-associated urinarytract infection, we carried out a randomized controlled trial of a neomycin-polymyxin irrigant administered through closed urinary catheters. Eighteen of 98 (18 per cent) of the patients not given irrigation became infected, as compared with 14 of 89 (16 per cent) of those given irrigation, yielding a mean daily incidence of 5 per cent in each group. The distribution of organisms and their antibiotic sensitivities differed in the two groups, the organisms from the patients with irrigation being more resistant. Disconnections of the catheter junctions were associated with high rates of infection. The rate of disconnections of the junctions in the group given irrigation was almost twice that of the control group because of the presence of the extra junction on overall infection rate represents the result of two opposing phenomena: the increased entry of organisms and the suppression of a portion of them.

Adult↗
PubMedDate not supplied

Multicenter epidemiologic and health services research on therapeutics in the HMO Research Network Center for Education and Research on Therapeutics.

Research and education programs in therapeutics that combine the data, organizational capabilities, and expertise of several managed care organizations working in concert can serve an important role when a single organization is not large enough to address a question of interest, when diversity in populations or delivery systems is required, and when it is necessary to establish consistency of results in different settings. Nine members of the HMO Research Network, a consortium of health maintenance organizations (HMOs) that perform public domain research, have formed a Center for Education and Research on Therapeutics (CERT), sponsored by the Agency for Healthcare Research and Quality, to conduct multicenter research in therapeutics. The CERT uses a distributed organizational model with shared leadership, in which data reside at the originating organization until they are needed to support a specific study. Extraction of data from the host computer systems, and some manipulation of data, is typically accomplished through computer programs that are developed centrally, then modified for use at each site. For complex studies, pooled analysis files are created by a coordinating center, and then analysed by investigators throughout the HMOs. It is also possible to contact HMO members when necessary. This multicenter environment has several benefits, addressing: (1) a wide array of questions about the safety and effectiveness of therapeutics, (2) the impact of efforts to change clinicians' and patients' behavior, and (3) pharmacoeconomic and pharmacogenetic questions.

Community Networks↗
PubMedDate not supplied

Methodologic aspects of clinical studies of perioperative antibiotic prophylaxis.

Many issues affect the design, conduct, and analysis of clinical evaluations of perioperative antibiotic prophylaxis. The most important of these are the selection of appropriate procedures for evaluation, the choice of meaningful outcomes, the comparison of outcomes among groups of patients who are really comparable to one another, the unbiased assessment of outcomes, the assessment of a number of patients sufficient to provide adequate statistical power for the detection of meaningful differences, and the generalizing of results. In evaluating perioperative prophylaxis, investigators often strive to identify small absolute differences among the risks of infections with different prophylactic regimens. For many specific procedures and drug regimens, such evaluations are limited by the difficulty of studying a sufficient number of individuals. Although randomized clinical trials are the standard for clinical evaluation, observational data may also prove useful under some circumstances.

Anti-Bacterial Agents↗
PubMedDate not supplied

Diagnosis and empiric therapy of urinary tract infection in the seriously ill patient.

Urinary tract infections (UTIs) are the most prevalent serious infections encountered by the typical physician. When these infections are an imminent threat, microscopic urinalysis rapidly provides sensitive and specific diagnostic information that can establish the diagnosis and guide initial therapy. Tests of localization of infection play no important role in early management decisions. The choice of empiric antibiotic therapy depends on the patterns of resistance in the patient's environment. Even when UTIs are nominally community acquired, an important minority of isolates are resistant to first-generation cephalosporins. Thus far the great majority of gram-negative urinary tract isolates have been susceptible to aminoglycosides and to third-generation cephalosporins. Appropriate therapy should promptly eradicate microscopically visible bacteriuria. Failure to do so after a day is presumptive evidence that the antibiotic is ineffective in vivo and is reason to change the antibiotic if the clinical condition warrants this. Conversely, the patient who fails to respond clinically despite eradication of microscopic bacteriuria is unlikely to fare better with a different antibiotic. In this setting, search for an isolated infected focus, such as an abscess, or for sites of dissemination of the infection is more likely to yield a solution.

Abscess↗
PubMedDate not supplied

Predictors of response to therapy for infections caused by Pseudomonas aeruginosa.

Data from 410 courses of cefsulodin therapy for infections caused by Pseudomonas aeruginosa were used to determine the factors that correlated with three outcomes: bacteriologic cure, clinical response, and the occurrence of adverse effects. The factors that were evaluated were site of infection, number of infected sites, prior antibiotic therapy, concurrent antibiotic therapy, maximum daily dose of cefsulodin, pretreatment status (blood pressure, white blood cell count, hemoglobin and creatinine levels, liver function tests), age, sex, and assignment to cefsulodin via randomization. Stepwise logistic regression analysis was used to determine the factors that contributed independently to the outcome. Regression analysis indicated that three factors were significantly associated with bacteriologic cure: age, site of infection, and pretreatment hemoglobin values. Regression analysis indicated that the following four variables were significant correlates of satisfactory clinical response: site of infection, the presence of more than one infected site, diastolic blood pressure before therapy, and prior antibiotic therapy. Regression analysis also indicated that two factors, maximum daily dose of cefsulodin and duration of therapy, were the only significant predictors of the occurrence of adverse effects.

Adult↗
PubMedDate not supplied

The outlook for prevention and treatment of infections due to Pseudomonas aeruginosa.

Control measures based on careful hospital surveillance are aimed primarily at minimizing environmental sources of Pseudomonas aeruginosa. Other important aspects of epidemiologic control include aggressive evaluation of outbreaks and limitation of antimicrobial use. Potent new antimicrobial chemotherapy has been developed, with most new agents of the beta-lactam and aminoglycoside classes. In spite of these developments, the likelihood of drug resistance seems great and the search for novel compounds continues. Of greatest appeal are approaches that augment host defences. Replacement or supplementation of circulating phagocytic cells is conceptually attractive, but this approach has encountered major technical problems and complications. More recently, there has been important progress in developing immunologic approaches aimed at augmenting circulating antibodies. Development of monoclonal antibodies and new methods for preparing hyperimmune globulins has produced forms of intervention that must be tested by clinical trials, but not all patients may benefit from augmentation of circulating antibodies to P. aeruginosa.

Anti-Bacterial Agents↗
PubMedDate not supplied

Effect of hydrogen ion and protein concentrations on the activity of beta-lactam antibiotics.

The susceptibility of 50 isolates of Staphylococcus aureus to seven beta-lactam antibiotics was measured under four conditions, involving two pH values and the presence or absence of serum protein. Multiple linear regression analysis was used to determine the effect of pH, protein, and antibiotic on the minimal inhibitory concentrations (MICs). Each of these factors as well as their interactions had significant effects on the MIC. The effects of pH and protein did not bear a predictable relationship to the extent of binding of antibiotic to serum proteins. All MICs were higher in the presence of protein at both pH values. For some antibiotics, the protein effect at pH 6.0 was larger than that at pH 7.4; for others the protein effect was smaller at pH 6.0. These data indicate that pH and protein effects must be determined individually for beta-lactam antibiotics.

Anti-Bacterial Agents↗
PubMedDate not supplied

Antibiotic prophylaxis in surgery.

Perioperative prophylaxis accounts for a substantial proportion of antibiotic use in acute-care hospitals. There is clinical evidence of its efficacy in a number of circumstances. These include hysterectomy, cesarean delivery, colorectal surgery, and some orthopedic procedures. Prophylaxis for cardiovascular surgery has not been evaluated rigorously enough to determine its efficacy. Because of the catastrophic consequences of serious infections following cardiovascular surgery, prophylaxis is widely used in this setting. There is relatively little information on the impact of prophylaxis on postoperative mortality, duration of hospitalization, or the costs of medical care. The studies that are available suggest that prophylaxis may reduce mortality and overall costs under some circumstances. Antibiotics with relatively long half-lives are theoretically attractive agents that merit careful evaluation in clinical trials. Many issues remain unresolved. The most important are the efficacy of prophylaxis in other settings, its impact on morbidity and costs, and the optimal agents and regimens.

Anti-Bacterial Agents↗
PubMedDate not supplied

Factors explaining lack of response to heel stick in preterm newborns.

OBJECTIVE: To determine factors explaining lack of response by preterm newborns to heel stick for blood sampling. DESIGN: A cross-sectional design based on secondary analysis of the control session of a randomized crossover design. SETTING: Four Level III neonatal intensive-care units of university teaching hospitals. PARTICIPANTS: 120 preterm newborns with an average age of 28 weeks postconceptional age. INTERVENTION: 24 newborns who showed a "no change" response according the Premature Infant Pain Profile were compared to the remaining 96 newborns who had shown a pain response. MAIN OUTCOME MEASURES: Age (postconceptional age at birth, postnatal age at study), Apgar score at 5 minutes, severity of illness, sex, race, wake/sleep state, previous study sessions, total number of painful procedures since birth, and time since last painful procedure. RESULTS: After stepwise logistic regression analysis the variables remaining in the final model that explained the difference between the groups were postnatal age at time of study, postconceptional age at birth, time since last painful procedure, and wake/sleep state. CONCLUSIONS: Newborns who were younger, asleep, and had undergone a painful event more recently were less likely to demonstrate behavioral and physiologic indicators of pain.

Age Factors↗