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Biomedical subjects

S Summers

Publications and source records attributed to S Summers.

At least 37 records · Page 2Linked to original sources
PubMed1993

Urokinase therapy for thrombosed hemodialysis access grafts.

Urokinase, with or without angioplasty, is an alternative to surgical treatment for the treatment of thrombosed polytetrafluoroethylene vascular access grafts. To evaluate the efficacy and outcome of thrombolytic therapy, all available charts of patients with a thrombosed graft treated at the University of California at Los Angeles Medical Center from June 1988 to August 1991 were reviewed. Twenty-three grafts in 21 patients underwent 43 procedures, 17 thrombolytic and 26 surgical, during this period. Four procedures in the thrombolytic group and the surgical group were patent less than 48 hours. Complications occurred in a significantly higher percentage of the thrombolytic group (11 of 17) than the surgical group (two of 26) (p < 0.001). Using life-table analysis, the primary patency was approximately 40 percent at six months and 20 percent at one year in both groups. Urokinase therapy was significantly more expensive than surgical therapy in this study. This increased cost was the result of ten of 17 patients receiving urokinase for more than eight hours. It is concluded that percutaneous delivery of thrombolytic therapy with angioplasty of any documented lesion is as effective as surgical procedure in the treatment of thrombosed hemodialysis access grafts, thrombolytic therapy is associated with a significantly higher complication rate and urokinase treatment that requires more than six to eight hours to lyse the graft thrombus may not be cost-effective.

Catheters, Indwelling↗
PubMed1993

Meta-analysis: strategies to strengthen postanesthesia care unit study results.

Meta-analysis is a research method used to synthesize findings across multiple studies that tested similar variables on similar subjects. An overview of meta-analysis is presented and defined in an eight-step approach. A meta-analysis of the effect of preoperative instruction on postoperative outcomes is applied to the eight defined steps. Implications for postanesthesia nurses include the usefulness of meta-analysis as a method of building knowledge by examining findings and drawing conclusions from multiple, single-institution studies conducted with small sample sizes.

Meta-Analysis as Topic↗
PubMed1993

Introduction to instrument development: scaling methods.

Deciding which instrument scale technique to choose is an important step in instrument development. Measurement theory dictates rules regarding level of measurement and approaches to decrease the error component of true scores. Measurement rules are applied to types of scaling, including methods to quantify demographic data, opinion rating scales, summated rating scales, semantic differential scales, and methods to quantify laboratory data. Consideration to scaling should be made before planning data analysis so that research questions or hypotheses can be answered using the appropriate statistical method.

Bias↗
PubMed1993

Establishing the reliability and validity of a new instrument: pilot testing.

Development of instruments to measure psychosocial variables is a complex process that begins with concept analysis and concludes with pilot testing to establish initial reliability and validity properties. Although the instrument development process is lengthy. PACU nurses are encouraged to follow all steps; if they do not, they will be unsure of what is measured or the meaning of the finding. Discussed here is the final phase of the instrument development process; calculating and analyzing construct validity and internal consistency reliability. An example is given that applies reliability and validity methods to a hypothetical instrument.

Factor Analysis, Statistical↗
PubMed1993

Critiquing research instruments for postanesthesia studies.

A recent series of articles instructed PACU nurses on steps in developing pencil-and-paper instruments for research studies. What questions should PACU nurses ask when considering the use of existing pencil-and-paper instruments for use in research studies? The purpose of this article is to present nine steps in critiquing existing instrument before conducting research studies. Included are ethical considerations when using instruments and a checklist to assist PACU nurses in critiquing existing instruments.

Ethics, Nursing↗
PubMed1992

HMEC-1: establishment of an immortalized human microvascular endothelial cell line.

The study of human microvascular endothelial cells has been limited, because these cells are difficult to isolate in pure culture, are fastidious in their in vitro growth requirements, and have a very limited lifespan. In order to overcome these difficulties, we have transfected human dermal microvascular endothelial cells (HMEC) with a PBR-322-based plasmid containing the coding region for the simian virus 40 A gene product, large T antigen, and succeeded in immortalizing them. These cells, termed CDC/EU.HMEC-1 (HMEC-1), have been passaged 95 times to date and show no signs of senescence, whereas normal microvascular endothelial cells undergo senescence at passages 8-10. HMEC-1 exhibit typical cobblestone morphology when grown in monolayer culture, express and secrete von Willebrand's Factor, take up acteylated low-density lipoprotein, and rapidly form tubes when cultured on matrigel. HMEC-1 grow to densities three to seven times higher than microvascular endothelial cells and require much less stringent growth medium. HMEC-1 will grow in the absence of human serum, whereas microvascular endothelial cells require culture medium supplemented with 30% human serum. These cells express other cell-surface molecules typically associated with endothelial cells, including CD31 and CD36 and epitopes identified by monoclonal antibodies EN4 and PAL-E. They also express the cell adhesion molecules ICAM-1 and CD44 and following stimulation with interferon-gamma express major histocompatibility complex class II antigens. HMEC-1 specifically bind lymphocytes in cell adhesion assays. Thus HMEC-1 is the first immortalized human microvascular endothelial cell line that retains the morphologic, phenotypic, and functional characteristics of normal human microvascular endothelial cells.

Antigens, Differentiation, Myelomonocytic↗
PubMed1992

Concept analysis methodology: applications to altered level of consciousness.

Concept analysis is the first step in instrument development. Steps in the concept analysis process are discussed and applied to the analysis of altered level of consciousness (ALC) as a potential nursing diagnosis for submission to the North American Nursing Diagnosis Association. Criteria regarding ALC have been defined for the assessment of neurologically impaired patients and not for the neurologically intact postanesthesia patient. It is assumed that postanesthesia patients experience chemically induced ALC, and consensus regarding what constitutes this concept needs to be validated by PACU nurses. The first step in instrument development is a clear definition of the concept of interest. The criteria for ALC determined by the PACU nurses could then be used to construct a pencil-and-paper instrument that would allow the concept to be tested on postanesthesia patients as they emerge from anesthesia. This concept analysis-to-instrument development process discussion can be applied to any concept of interest to the PACU nurse.

Consciousness↗
PubMed1992

Validation of concepts: the next step in instrument development for postanesthesia studies.

Validation of concepts through descriptive research is a major step in instrument development. The concept of hypothermia as observed in the postanesthesia patient is discussed, and data are compared with the North American Nursing Diagnosis criteria of hypothermia. What emerges from the data are items specific to postanesthesia patients, which have been labeled as inadvertent postanesthesia hypothermia (IPH). Thus, the importance of concept analysis in instrument development is emphasized because the omission of this step from instrument development may result in lack of clarity or "fuzzy data" in what is to be measured.

Anesthesia↗
PubMed1992

Instrument development: writing the items.

An important step in instrument development is writing the items that are derived from concept analysis and validation. It is also important to determine if the instrument is to be constructed for criterion-referenced or norm-referenced measurement; examples for both are discussed. Also discussed are methods for developing a blueprint for a psychosocial instrument. Additional methods presented are how to construct the items as simple rather than complex sentences, to keep the sentences short and unambiguous, and to construct the items for an eighth-grade reading level to facilitate patient use.

Data Collection↗
PubMed1992

Using microcomputers to facilitate research studies.

Microcomputers can facilitate research studies planned by busy PACU nurses. PACU nurses need to become computer literate to take advantage of these time-efficient methods. Computer hardware and software can be used to word process a research proposal, statistical software can be used for data analysis, and graphic and clip-art software can be used to summarize and to graphically present the results of this study.

Clinical Nursing Research↗
PubMed1992

Introduction to instrument development for postanesthesia studies.

An important aspect of any research project is the selection of the instrument for which a "fit" exists between what is to be studied and the subjects. Physiological instruments are developed to objectively measure specific variables, such as temperature. Psychological instruments are usually developed to subjectively measure specific variables; however, there may not be a fit if the researcher used a paper-and-pencil instrument developed to measure anxiety in psychiatric patients to measure anxiety in the sedated, postanesthesia patient. An introduction to instrument development is presented including defining instruments, deciding what phenomena to measure and how to measure them, locating existing instruments, deciding when to develop an instrument, and identifying implications that arise from the use of inappropriate instruments.

Clinical Nursing Research↗
PubMed1991

Selecting the sample for a research study.

Sample selection is a very important but sometimes underestimated part of a research study. Sampling theory describes two sampling domains: probability and nonprobability. Probability samples contain some type of randomization and consist of simple, stratified, systematic, cluster, and sequential types. Nonprobability samples lack randomization and consist of convenience or accidental, purposive, quota, volunteer, and expert types. The primary distinction between the two domains is that the probability sampling study findings can be generalized to the target population while the nonprobability sampling study findings can only be generalized to the institution where the sample was studied.

Humans↗
PubMed1991

Axillary, tympanic, and esophageal temperature measurement: descriptive comparisons in postanesthesia patients.

Body temperature in postanesthesia patients is considered to be an important vital sign; yet, measurement sites may vary from oral to axillary and rectal to tympanic membrane. The reviewed literature indicated that axillary and rectal temperatures are measures of shell temperature and esophageal and tympanic temperatures are measures of core temperature. This study compared temperatures measured with axillary mercury-in-glass and electronic thermometers with those measured by tympanic and esophageal thermometers in 96 postanesthesia patients. Analysis of the data using paired t test indicated there was no significant difference between the esophageal and tympanic temperatures; however, significant differences were found between mercury and electronic axillary temperatures. Analysis of variance indicated no significant difference between the axillary temperatures as measured by mercury and electronic methods in the arm extended on an arm board during surgery. Further studies are needed using a larger, randomly selected sample to validate this study's findings.

Adult↗
PubMed1991

Level of measurement: key to appropriate data analysis.

While PACU nurses are increasingly conducting research studies to validate nursing practice, it is important to consider logical rules for data analysis. Level of measurement is an important consideration when selecting statistical tests to analyze the data. Statistical tests need not remain a mystery since level of measurement is the deciding factor for selecting which tests are appropriate for answering the research questions or testing the hypotheses.

Clinical Nursing Research↗
PubMed1991

Steps in reviewing literature.

Reviewing the literature is an important part of the research process. Systematic steps to follow when evaluating the literature include critiquing the following: title, abstract, problem, purpose, theoretical or conceptual framework or model, implications for nursing, review of literature, hypotheses or research questions, variables, instruments, subjects, ethical concerns, research designs, results, conclusions, recommendations, and future studies. Frequently, the reader must search for these topics since few studies list the above as separate headings; however, it is important to evaluate each to determine a study's relevance to the reader's research needs.

Humans↗
PubMed1991

Defining components of the research process needed to conduct and critique studies.

The research process consists of a five-chapter approach. Chapters one through three are written during the planning stages of a study. Chapter one consists of problem, purpose, hypotheses or research questions, definitions, theoretical framework, and significance for nursing. Chapter two consists of the review of literature. Chapter three consists of the methodology: sample, setting, design, data analysis methods, and ethical concerns. Chapters four and five are written after the study is completed. Chapter four consists of results of data analysis. Chapter five consists of a discussion of results, conclusions, implications for nurses, and recommended future studies. It is important for nurses to review and apply this five-chapter approach when conducting or critiquing research studies.

Data Collection↗