Central venous catheter-related bloodstream infections: an analysis of incidence and risk factors in a cohort of 400 patients

OBJECTIVE

To determine the incidence of central catheter-related bloodstream infection (CR-BSI) and to compare patient and catheter characteristics of those with and without CR-BSI from a clinically suspected subgroup. Secondly, to assess the efficacy of the acridine orange leucocyte cytospin test (AOLC) as a rapid in situ method of detecting central venous catheter (CVC) infection.

DESIGN

One-year prospective audit.

SETTING

Intensive care unit/high dependency unit (ICU/HDU) and general wards of a tertiary referral hospital.

PATIENTS AND PARTICIPANTS

400 patients with non-tunnelled CVCs.

INTERVENTIONS

Daily surveillance, blood culture from peripheral venepuncture, blood sample from the CVC for assessment of the AOLC test and removal of suspected CVCs were carried out on patients clinically suspected of having CR-BSI.

MEASUREMENTS AND RESULTS

CR-BSI was diagnosed using well defined criteria. Infection rate was calculated by dividing the number of definitive catheter associated infections by the total number of appropriate catheter in situ days. The AOLC test was performed on all those with suspected CR-BSI. A total of 499 CVCs in 400 patients were assessed, representing 3014 catheter in situ days. Over 80 % of patients were from our ICU/HDU, representing 404 CVCs and 1901 catheter in situ days. A total of 49/499 (9.8%) CVCs in the same number of patients were suspected of being infected subsequently 12/499 (2.4 %) CVCs [95% confidence interval (CI) 1.25 to 4.16] in 12 separate patients were demonstrated to be the direct cause of the patient's BSI. Rates of CR-BSI per 1000 catheter days were 3.98 (95 % CI 2.06 to 6.96) for the whole cohort and 4.20 (95 % CI 1.81 to 8.29) for the ICU/HDU subgroup. In the group suspected of having CR-BSI, CVCs were removed unnecessarily in 55 %, and no patient or catheter variables measured were predictive of the development of CR-BSI. The AOLC test was negative in all 12 catheters subsequently shown to be the definitive cause of BSI.

CONCLUSIONS

We have defined the incidence of CR-BSI in a cohort of patients from a tertiary referral hospital, the rates comparing favourably with those reported for similar populations. We were unable to demonstrate significant differences in any patient or catheter variables between those with and without CR-BSI. The AOLC test used alone was unhelpful as a method to diagnose in situ CVC infection in this patient population.

Prospective evaluation of systematic sextant transition zone biopsies in large prostates for cancer detection

OBJECTIVES

A prospective evaluation was performed to define the role of systematic transition zone (TZ) biopsies in prostates larger than 50 cc.

METHODS

From August 1994 to July 1997, 213 consecutive patients referred because of an abnormal digital rectal examination or prostate-specific antigen greater than 4.0 ng/mL had a calculated prostate size greater than 50 cc by transrectal ultrasound (TRUS) measurement. These patients underwent TRUS-guided sextant biopsies of the peripheral zone (PZ) and TZ.

RESULTS

The median calculated prostate size was 70 cc with a TZ size of 39 cc. Fifty-five cases of carcinoma of the prostate were found, giving a 26% detection rate. The TZ biopsies detected cancer in 30 of the 55 patients (55% sensitivity) compared with the 47 patients detected by the PZ biopsies (85% sensitivity). Seven cancers (13%) were detected only by the additional TZ biopsies. TZ biopsies revealed bilateral tumors when the PZ biopsies had shown unilateral disease in 2 cases. In 6 cases the TZ biopsies showed higher Gleason grade tumors than was found in the PZ. In the 30 cases with positive TZ biopsy, concordance between the PZ and TZ biopsies occurred in 74% (133 of 180) of the sectors. The PZ biopsy detected cancer in 43 of 66 corresponding sectors that had positive TZ biopsies, giving a sensitivity of 65% and a negative predictive value of 80%.

CONCLUSIONS

Routine PZ biopsies missed detecting 13% of the cancers found with the addition of sextant TZ biopsies in patients with large prostates (greater than 50 cc). In addition, 14% of the patients with cancer had upgrading or detection of bilateral tumor with the added biopsies. Routine systematic sextant TZ biopsies should be considered in patients with prostates greater than 50 cc in size.

Medical student knowledge of morphine for the management of cancer pain

Inadequate training of physicians contributes to the undertreatment of cancer pain. To address these concerns, the University of Kentucky has introduced a 4-week course for final-year medical students that teaches the principles of clinical pharmacology and pain management. The purposes of this study are to assess the knowledge deficits of final-year medical students about the use of morphine for cancer pain and to assess the efficacy of a short course on cancer pain management. Eighty-six final-year medical students completed a 22-item questionnaire assessing their knowledge and attitudes toward the use of morphine for cancer pain. Students indicated their agreement with each statement on a four-point scale (one, strongly disagree; four, strongly agree). All students then completed a compulsory short course on pain management. The course content included a 1-hr lecture on chronic nonmalignant pain, a 1-hr lecture on acute pain management, and a 1-hr lecture on cancer pain management. In addition, students completed small-group, problem-based learning modules on several aspects of pain management. After the course, all students completed the same 22-item survey. The alpha reliability score of the pretest instrument was 0.55, and the posttest reliability was 0.86. Upon course completion, students agreed most strongly (mean +/- SEM) that morphine should be given on a regular schedule for cancer pain (3.41 +/- 0.08), that cancer pain management frequently requires co-analgesics (3.36 +/- 0.06), and that patients with good pain relief function better than those with continuing pain (3.39 +/- 0.08). A comparison of pretest and posttest means on specific items suggested that the greatest amount of learning took place in the following content areas: morphine is a good oral analgesic; increases in cancer pain should be treated by increasing the morphine dose; respiratory depression is not a concern for cancer pain patients; and morphine can be used over a wide range of doses. The regular use of morphine was recognized as the treatment drug of choice for cancer pain. The students showed improved knowledge scores on ten of the 22 items on the posttest survey. A significant increase in learning occurred on six knowledge and attitude items. On only one item (nausea as a side effect of morphine) did the knowledge scores decrease on the posttest. A significant minority (40%) of senior medical students had deficits in knowledge about the use of morphine for cancer pain. The risk of addiction, respiratory depression, and tolerance were misunderstood by a significant minority (25%) of students.

Charging for intensive care using direct nursing hours as the cost marker

The hypothesis that direct nursing hours correlate with the cost of a patient stay in intensive care was tested. One hundred and thirty-nine patients were studied and the data collected included: (a) direct nursing hours applied to each patient; (b) a daily TISS score: (c) a detailed costing of each patient (all costs are shown in N.Z.$). There was a strong correlation between the direct nursing hours and the total cost per patient (r2 = 0.98) (total cost = 54 x direct nursing hours + 344). Also a strong correlation existed between the total TISS scores and the total costs per patient (r2 = 0.96) (total cost = 67.13 x TISS). Direct nursing hours offer a relatively simple and logical method of allocating costs per patient.

A written guideline implementation can lead to reductions in laboratory testing in an intensive care unit

The impact of developing guidelines for laboratory testing in an Intensive Care Unit (ICU) was examined. Targeted blood tests were recorded on fifty cardiac surgery and fifty general intensive care patients retrospectively. Following the introduction of guidelines, the study was repeated with prospective data collection. Comparison of the samples before and after the intervention showed a 25.9% reduction in all blood tests and a 17.1% reduction in arterial blood gases in the post cardiac surgery group. In general ICU patients, the drop in all tests was 16.6% and in arterial blood gases 21.9%. The cost saving from the cardiac surgery sample was N.Z.$3,637 and general ICU N.Z.$3,166, giving a sum total of N.Z.$6,803 in 100 patients. The potential cost savings for the annual admissions of 1,200 patients is N.Z.$81,636. This study shows that written guidelines can bring about major cost reduction in the short-term.

Myogenic vector expression of insulin-like growth factor I stimulates muscle cell differentiation and myofiber hypertrophy in transgenic mice

The avian skeletal alpha-actin gene was used as a template for construction of a myogenic expression vector that was utilized to direct expression of a human IGF-I cDNA in cultured muscle cells and in striated muscle of transgenic mice. The proximal promoter region, together with the first intron and 1.8 kilobases of 3'-noncoding flanking sequence of the avian skeletal alpha-actin gene directed high level expression of human insulin-like growth factor I (IGF-I) in stably transfected C2C12 myoblasts and transgenic mice. Expression of the actin/IGF-I hybrid gene in C2C12 muscle cells increased levels of myogenic basic helix-loop-helix factor and contractile protein mRNAs and enhanced myotube formation. Expression of the actin/IGF-I hybrid gene in mice elevated IGF-I concentrations in skeletal muscle 47-fold resulting in myofiber hypertrophy. IGF-I concentrations in serum and body weight were not increased by transgene expression, suggesting that the effects of transgene expression were localized. These results indicate that sustained overexpression of IGF-I in skeletal muscle elicits myofiber hypertrophy and provides the basis for manipulation of muscle physiology utilizing skeletal alpha-actin-based vectors.

Relation of boron to the composition and mechanical properties of bone

A review of the experimental studies relating boron to biological effects on appendicular and axial bones in animal models suggests that numerous influences, known and unknown, affect the responsiveness of bone to dietary boron. Degrees of skeletal response to boron are modified by other nutritional variables that include calcium, magnesium, vitamin D, and fluoride. Evidence suggests that appendicular and axial bones may differ in their responses. Tests of the mechanical properties of bones may provide useful criteria for assessing the impacts of boron status on bone. These tests might resolve questions about optimal intakes of boron because mechanical properties sometimes respond to boron when composition of bones does not. Difficulty in interpreting some of the existing research arises because of the incipient state of knowledge regarding boron nutriture, to analytical problems associated with determining accurately the small quantities of boron in feed and tissues, and to technological difficulties in controlling extraneous exposure of experimental animals to boron. Yet there is considerable evidence that both compositional and functional properties of bone are affected by boron status.

Swimming upstream: the strengths of women who survive homelessness

A study of the strengths and personal resources of women who had overcome homelessness revealed that the experience of homelessness for these women was a temporary state of disruption resulting from an effort to free themselves from conditions associated with despair, such as abuse or addictions, and to search for a better life. Personal, interpersonal, and transpersonal categories of strengths were identified that enabled these women to move in a positive direction toward health and self-actualization. The synthesizing metaphor "swimming upstream" describes the stoic determination required to go against the overwhelming negative forces of their environment.

Hyperuricemia and urate nephropathy in urate oxidase-deficient mice

Urate oxidase, or uricase (EC 1.7.3.3), is a purine metabolic enzyme that catalyzes the conversion of uric acid to allantoin in most mammals except humans and certain other primates. The loss of urate oxidase in the human during primate evolution predisposes man to hyperuricemia, a metabolic disturbance that can lead to gouty arthritis and renal stones. To create a mouse model for hyperuricemia and gout, and to address the question of whether urate oxidase is essential in lower mammalian species, we have disrupted the urate oxidase gene in the mouse by homologous recombination in embryonic stem cells. Unlike the human situation, urate oxidase deficiency in mice causes pronounced hyperuricemia and urate nephropathy. More than half of the mutant mice died before 4 weeks of age, indicating that urate oxidase is essential in mice. These mutant mice may also serve as animal models for hyperuricemia and its related nephropathy in humans.

Caring and nursing's metaparadigm: can they survive the era of managed care?

Considering the growing power of third-party payers to control the length and methods of treatment, the authors summarize alternative treatment models of providing care. These models are evaluated within the context of nursing's metaparadigm. Clinical examples are provided to illustrate how focusing on client strengths and alternative solutions differs from more traditional approaches to treatment.

Gene targeting yields a CD18-mutant mouse for study of inflammation

CD18 is the common beta subunit for the heterodimeric leukocyte integrins that mediate many inflammatory cell adhesion responses including binding to intercellular adhesion molecules 1 and 2. CD18 deficiency in humans causes a severe granulocyte disorder with susceptibility to bacterial infections and high morbidity and mortality. Gene targeting was used to prepare an insertion mutation in the murine CD18 gene. The insertion mutation resulted in a hypomorphic rather than a null allele due to low expression from a cryptic promoter in the plasmid construct. Homozygous mutant mice are viable and fertile, demonstrate a mild granulocytosis, and have 2 or 16% of normal CD18 expression on granulocytes in the resting or activated state, respectively. Mutant mice show an impaired inflammatory response to a chemical peritonitis and delayed rejection of cardiac transplants. These CD18-mutant mice provide a model of the moderate form of the human disease and should be extremely valuable for in vivo analysis of the role of leukocyte integrin-dependent adhesion in inflammatory disease models.

Gene targeting yields a CD18-mutant mouse for study of inflammation

CD18 is the common beta subunit for the heterodimeric leukocyte integrins that mediate many inflammatory cell adhesion responses including binding to intercellular adhesion molecules 1 and 2. CD18 deficiency in humans causes a severe granulocyte disorder with susceptibility to bacterial infections and high morbidity and mortality. Gene targeting was used to prepare an insertion mutation in the murine CD18 gene. The insertion mutation resulted in a hypomorphic rather than a null allele due to low expression from a cryptic promoter in the plasmid construct. Homozygous mutant mice are viable and fertile, demonstrate a mild granulocytosis, and have 2 or 16% of normal CD18 expression on granulocytes in the resting or activated state, respectively. Mutant mice show an impaired inflammatory response to a chemical peritonitis and delayed rejection of cardiac transplants. These CD18-mutant mice provide a model of the moderate form of the human disease and should be extremely valuable for in vivo analysis of the role of leukocyte integrin-dependent adhesion in inflammatory disease models.

Left ventricular myocardial blood flow, metabolism, and effects of treatment with enalapril: further insights into the mechanisms of canine experimental pacing-induced heart failure

Left ventricular myocardial blood flow and metabolic parameters were studied in dogs with severe heart failure induced by rapid ventricular pacing. The impact of early administration of enalapril was also evaluated. Seventeen dogs were randomly assigned in a blinded fashion to receive enalapril at a dose of 10 mg orally per day or a matching placebo commencing 1 week after initiation of pacing. Six dogs underwent sham operations and served as a control for the myocardial blood flow and metabolic studies. In general, there was no significant difference in myocardial blood flow among the control dogs, the placebo-treated, and the enalapril-treated, paced dogs. However, tissue adenosine triphosphate was markedly reduced in both the enalapril-treated, paced dogs (2.43 +/- 0.55 mumol/gm wet weight, mean +/- SD) and the placebo-treated, paced dogs (2.79 +/- 0.39 mumol/gm) compared with the level in control dogs (4.77 +/- 0.88 mumol/gm, both p < 0.01). Tissue glycogen and lactate levels were similar in the three groups. The time to development of severe heart failure tended to be longer in the enalapril-treated dogs (33 +/- 12 days) than in the placebo-treated dogs (24 +/- 10 days, p = 0.07). In pacing-induced heart failure, therefore, an imbalance between energy supply and demand may contribute to the left ventricular dysfunction, myocardial ischemia does not play a major role, and early treatment with enalapril may prolong the time to development of severe heart failure.

Energy status of the rapidly paced canine myocardium in congestive heart failure

Rapid ventricular pacing (RVP) is used as an experimental model of congestive heart failure (CHF). The purpose of this study was to determine the energy status of the dog myocardium after the development of CHF via chronic RVP. The myocardium had a significantly lower (P < 0.05) energy charge (EC) during CHF (0.63 +/- 0.01) than in sham-operated controls (0.82 +/- 0.02). This was due to significant differences in concentrations in ATP (-48%), ADP (29%), and AMP (275%) in the RVP group. However, the total adenine nucleotide pool was not different between groups. Myocardial lactate concentration was also similar. Glycogen was significantly lower (P < 0.05) by 20% at peak CHF. The adenine nucleotides were similar among the different myocardial layers (endo-, mid-, and epicardium). The administration of enalapril (an inhibitor of angiotension-converting enzyme) to decrease vascular resistance had no effect on the myocardial energy status of CHF dogs. These findings suggest that the lower EC in CHF animals is not the result of subendocardial ischemia. Also, lower EC is not associated with endogenous glycogen depletion or increased lactate concentration. The energy status of the myocardium in RVP-induced CHF is unlike that seen in ischemia-induced heart failure. This suggests that CHF in RVP is not vascular in origin.

Personal response systems in the United States

In summation, although Personal Response Systems are relatively new in the marketplace they have made tremendous inroads over the past fifteen years. The next decade presents some difficult problems for this country in terms of its aging population and the delivery of quality, cost effective health care to all who need it. In light of these problems, the PRS industry can offer viable solutions-solutions for the U.S. health care system in helping to control and reduce the cost of health care delivery; solutions for industry in attempting to meet their employee health care needs; solutions for families who are coping with the strains of eldercare; and most important, solutions for many people who, regardless of age, could not live independently without a Personal Response System.

Lymphoepithelioma-like carcinoma of the lung

Historically lymphoepithelioma was a term used to describe an undifferentiated mucosal carcinoma with a lymphocytic component arising only from the nasopharynx, although recently, lymphoepithelioma-like carcinoma has been found to occur as a primary tumor of the lung. Thus far, five patients have been documented as having this rare anatomical presentation. The patient that is being presented is the latest case of lymphoepithelioma-like carcinoma of the lung and will be compared clinically and histologically with the other four cases. The case is presented in order to discuss optimal methods of diagnoses and treatment for this condition.

Effects of different rates of cardiac pacing on rat myocardial energy status

The energy status of mammalian cells is a finely regulated phenomenon. This is especially true in cardiac muscle cells in which energy requirements are high and the system must provide rapid turnover of the adenine nucleotides and instant response to changes in energetic demands. We have examined the acute response of the rat myocardium to ventricular pacing up to 2.5 times the resting heart rate. The purpose of this study was to determine at what level of pacing the normal energy status could be maintained and at what point it was compromised. Myocardial energy charge (EC = (ATP + 0.5 ADP)/(ATP + ADP + AMP] was maintained at 1, 1.5 and 2 times the resting heart rate but declined significantly at 2.5 times. In contrast, phosphorylation potential (PP = ATP/ADPf x Pi) was drastically altered in hearts paced at 1.5, 2 and 2.5 times the resting rate. Tissue lactate increased and glycogen decreased in a linear fashion as pacing rate increased, indicating that the metabolic challenge was proportional to the pacing rate. EC seems to reflect the overall status of the cell and its ability to maintain a dynamic equilibrium. PP may reflect the immediate and necessary driving force for mitochondrial respiration in times of increased demand. These data suggest that the myocardium may meet the increased energy demands of acute ventricular pacing by shifting the molar ratio of ATP to ADP times Pi in favour of driving phosphorylation.

Targeted disruption of the c-src proto-oncogene leads to osteopetrosis in mice

To understand the normal, physiological role of the c-src proto-oncogene, a null mutation was introduced into the gene by homologous recombination in mouse embryonic stem cells. Two independent targeted clones were used to generate chimeras that transmitted the mutated allele to their offspring. Intercrossing of heterozygotes gave rise to live born homozygotes, but most of these mice died within the first few weeks of birth. Histological and hematological examination of the homozygous mutants did not reveal detectable abnormalities in the brain or platelets, where src is most highly expressed. However, these mutants were deficient in bone remodeling, indicating impaired osteoclast function, and developed osteopetrosis. These results demonstrate that src is not required for general cell viability (possibly because of functional overlap with other tyrosine kinases related to src) and uncover an essential role for src in bone formation.

Improving access to pediatric health care in Mississippi

Working under the Mississippi Postneonatal Death Impact Project, the Mississippi Chapter of the American Academy of Pediatrics, in conjunction with the State Department of Health, helped improve access to pediatric health care in Mississippi. This was accomplished by developing a statewide telephone information and referral service (telephone case management), enlisting primary care physicians to treat a limited number of children without specific compensation and staging a public awareness campaign. System barriers encountered were identified and interagency coordination and cooperation suggested. This effort could be easily replicated and expanded.

The role of phospholipase A2 in microsomal lipid peroxidation induced with t-butyl hydroperoxide

The role of phospholipase A2 (PlA2) in lipid peroxidation induced with t-butyl hydroperoxide was examined in rat liver microsomes. Exposure of microsomes to t-butyl hydroperoxide was associated with activation of endogenous PlA2. When PlA2 was inhibited with chlorpromazine, mepacrine, or p-bromphenacyl bromide, the accumulation of thiobarbituric acid reactive substances (TBARS) was reduced in a dose dependent manner. In contrast, the accumulation of conjugated dienes was not affected by chlorpromazine, and was slightly increased by mepacrine. When endogenous PlA2 was activated with mellitin prior to induction of peroxidation, accumulation of both TBARS and dienes was reduced. Analogously, pretreatment with exogenous PlA2 reduced both dienes and TBARS. In contrast, addition of mellitin following the induction of peroxidation did not alter either TBARS or dienes.