Advanced nursing practice: an introduction to physical assessment.

Changing philosophies of clinical management and moves to reduce junior doctors' hours have led to increasing pressure upon nurses to take on the responsibility for assessing and initiating the management of acutely ill patients. Although nurses have been educated to assess, plan, and deliver care in a format known as the nursing process, this does not fully equip them for the demands of their rapidly developing roles. With increased responsibility comes the risk of increased stress and legal accountability, particularly where inadequate support is provided. In an effort to address this matter, this article briefly considers the theory of gaining clinical expertise, and describes a framework to facilitate physical assessment.

Artificial ventilation in the prone position.

Turning a ventilated patient into the prone position can greatly enhance arterial blood oxygenation independent of ventilator parameters. This article explores the physiology relating to pulmonary ventilation, highlighting an overall improvement in ventilation/perfusion matching as a result of the prone position. A series of small studies seems to suggest that prone positioning can have a dramatic effect on life-threatening hypoxia, including adult respiratory distress syndrome (ARDS) but as yet there have been no large, randomised, multi-centre trials to put beyond doubt the benefits of prone ventilation. Turning the patient prone precipitates many issues in caring for him/her in this position. Many are practical problems and the article goes on to explore a variety of these, including turning and positioning the patient, emergencies and access and the psychological effects of being in the prone position. It is important that nurses understand the physiological basis for any actions, including turning the patient prone, but it is also important that nurses doctors and other professionals appreciate the practical difficulties that this form of management can produce. All team members must work together to ensure a safe, cohesive approach to turning and caring for the ventilated patient in the prone position.

Sternotomy infection with Mycoplasma hominis: a cause of "culture negative" wound infection.

Wound infections with Mycoplasma species are unusual; diagnosis may be delayed because of the growth characteristics of this organism. We report Mycoplasma hominis infection of sternotomy wounds in two patients. The first presented with fever and drainage from the incision 1 week after coronary artery bypass grafting. The other patient presented with drainage from the incision three weeks after double-lung transplantation. In both cases, initial cultures were negative, but the typical colonial morphology of M. hominis was subsequently detected. Successful treatment consisted of debridement and long courses of antibiotic therapy; omental flap grafting was eventually required for the second patient. Other published cases were reviewed and compared with the newly reported cases.

Aberrant Histoplasma capsulatum. Confirmation of identity by a chemiluminescence-labeled DNA probe.

A cottony, light tan, filamentous fungus with pear-shaped microconidia and lacking tuberculated macroconidia was isolated from a bronchial lavage specimen. Subculture on several media at 37 degrees C failed to convert the fungus to a yeast form after several weeks; attempts at in vivo conversion in mice were also unsuccessful. Sera obtained several months apart showed M bands with Histoplasma capsulatum (HC) antigen by immunodiffusion and an increase in complement fixation titers with mycelial and yeast phase antigens of HC. Parallel identity was obtained on two occasions with exoantigen culture confirmation reagents for HC from Immuno-Mycologics as well as one of identity with Nolan reagents. Extracts from four Chrysosporium spp. strains had no identity reactions with HC with either kit. The fungus was identified as HC by the Accuprobe Histoplasma chemiluminescence-labeled DNA probe directed at ribosomal RNA, whereas all four Chrysosporium spp. isolates tested negative. DNA probes are a fast and accurate method to confirm the identity of aberrant fungal isolates.

Comparison of vidas Clostridium difficile toxin-A assay and premier C. difficile toxin-A assay to cytotoxin-B tissue culture assay for the detection of toxins of C. difficile.

Damage to the intestinal mucosa by Clostridium difficile (CD) is toxin mediated. Two enzyme immunoassays (EIAs) for toxin-A detection, the automated Vitek immunodiagnostic assay system CDA (Vidas CDA), and the Premier toxin A (Premier) were tested for their ability to detect toxin A in 301 stool samples and compared with an in-house tissue culture assay for toxin B (TCA). Of these 301 samples, 49 were TCA positive and 252 were TCA negative. Agreement between Vidas CDA and TCA on the initial run was 85% (255 of 301) and increased to 94% (278 of 296) when discordant samples were retested from available frozen specimens. Corresponding levels of agreement for Premier were 91% (272 of 301) and 98% (284 of 288), respectively. If tissue culture positivity at any titer was used as the sole criterion for positivity of the specimen, agreement with positive TCA before and after repeat testing was 57% (26 of 49) and 74% (34 of 46) for Vidas CDA and 65% (32 of 49) and 95% (36 of 38) for Premier. Agreement with negative TCA titers was good: 90% for Vidas CDA and 95% for Premier, and 98% for Vidas CDA and 99% for Premier after repeat testing. Predictive values positive and negative after repeat testing were, respectively, 88% and 96% for Vidas CDA, and 95% and 99% for Premier. Results for the automated and manual EIA methods for detection of C. difficile toxin A were obtained in 2.5 h as compared with 36-48 h for tissue culture.

Comparison of the Vitek Immunodiagnostic Assay System with an indirect immunoassay (Toxostat Test Kit) for detection of immunoglobulin G antibodies to Toxoplasma gondii in clinical specimens.

The value and convenience of testing for specific anti-Toxoplasma gondii antibodies have led to the development of various antibody detection methods, such as the enzyme immunoassay. Two enzyme immunoassays, the Vitek Immuno-Diagnostic Assay System (VIDAS; Vitek Systems, Hazelwood, Mo.) and the Toxostat Test Kit (TST; Whittaker Bioproducts, Walkersville, Md.), were compared for their ability to detect T. gondii immunoglobulin G antibodies in fresh human sera. Specimens were tested according to the instructions of each manufacturer. Of 304 serum specimens tested, the results for 282 (93%) agreed in both assays (77 were positive and 205 were negative). The results for the remaining 22 (7%) specimens were discrepant; 20 of the 22 specimens tested low positive or equivocal by Toxostat and negative by VIDAS. Upon retesting, 8 of these 22 specimens were in concordance, increasing the level of agreement to 95.3%. Intra-assay reproducibility was tested with four to nine replicates of each of seven samples (four positive, one negative, and two equivocal) by both tests and six replicates of one standard by VIDAS. Coefficients of variation (CVs) for VIDAS were 6, 8, 10, 15, 18, 19, and 23% for the samples and 14% for the standard. For Toxostat the CVs were 2, 8, 10, 10, 13, and 16%. In general, CVs for VIDAS were slightly larger than the CVs for Toxostat. Day-to-day variability over 3 days was tested by VIDAS for only six samples (three positive, two negative, and one equivocal) and four standards; CVs ranged from 2 to 15% for the samples and from 6 to 13% for the standards. In conclusions, VIDAS is a rapid, convenient, non-labor-intensive, and easily performed test for the detection of immunoglobulin G antibodies to T. gondii in serum specimens.

Corneal microsporidioses: characterization and identification.

Two ocular infectious disorders attributed to Microsporidia have been observed. They differ in that one infection involves the corneal stroma leading to corneal ulceration and suppurative keratitis whereas the other infection involves the conjunctival and corneal epithelium. The corneal stromal infection is caused by a binucleated oval spore that is Nosema-like in character. The conjunctival and corneal epithelial infection occurs in HIV-sero-positive individuals and is caused by a spore containing a single nucleus that is a member of the genus Encephalitozoon. Characteristics of these genera and the above-mentioned infections are presented.

Corneal microsporidiosis in a patient with AIDS.

Microsporidia are obligate intracellular protozoan parasites that are becoming increasingly recognized as opportunistic pathogens in patients with AIDS. They have been associated with enteritis, hepatitis, and peritonitis and recently keratoconjunctivitis. Gram stain demonstrates the presence of these organisms on light microscopic sections. The specific diagnostic features that distinguish microsporidia from other small nonspore-forming organisms are best demonstrated by electron microscopy, which is also used to characterize the members of Microsporea. In this study, salient histopathologic features of microsporidia in corneal epithelium obtained from an HIV-seropositive individual who developed AIDS are illustrated and discussed.

Acanthamoeba and disinfection of soft contact lenses.

The association between acanthamoeba keratitis and the use of soft contact lenses is firmly established. Despite alerts and warnings, education of eye-care professionals and patients, and identification of risk factors that are associated with the use of soft contact lenses, acanthamoeba keratitis remains a threat. It is presumed that in some cases, the soft contact lens is the vector by which Acanthamoeba is introduced to the cornea. This presumption has spurred concern regarding the efficacy of systems used for the disinfection of soft contact lenses in killing the organism. Many questions have been raised regarding the proficiency of disinfection. These have stemmed from a poor understanding of the interactions among soft contact lenses, soft contact lens paraphernalia, and Acanthamoeba. Another issue to be addressed is the need for standardized testing of the efficacy of contact lens disinfection systems against Acanthamoeba. Only through a concerted and focused effort by eye-care and other concerned health care professionals can these questions be answered.

Rapid identification of Staphylococcus epidermidis.

A panel of Minitek sugar disks, consisting of trehalose, mannitol, xylose, and sucrose, was evaluated for its ability to identify blood culture isolates of Staphylococcus epidermidis (SE). Using a heavy suspension of organism in Mueller-Hinton broth, 50 microL was pipetted onto each disk in wells of a flat-bottomed microtiter tray. The tray was covered, incubated in a moist chamber in non-CO2 at 35 degrees C, and examined after 5 and 24 hours. A color change of yellow or orange was positive; no color change (red) was negative. Expected reactions for SE were as follows: negative trehalose, mannitol, and xylose; positive, sucrose. On evaluation of 227 coagulase-negative staphylococci (CNS) at 5 and 24 hours, the panel had a sensitivity of 94 and 96%, specificity of 92 and 89%, predictive value of positive tests of 97 and 96%, and predictive value of negative tests of 84 and 87%. This panel offered an inexpensive and convenient method for differentiating SE from the other CNS in five hours.

Electrically evoked contractions of the triceps surae during and following 21 days of voluntary leg immobilization.

The effects of 21 days voluntary leg (plaster) immobilization on the mechanical properties of the triceps surae have been studied in 11 young female subjects, mean age 19.4 years. The results show that during the period of immobilization the mean time to peak tension (TPT) and half relaxation time (1/2RT) and tension (Pt) of the maximal twitch increased significantly (p less than 0.001) but the effects were short lived. Maximal tension and contraction times of the twitch recovered within 2-14 days following the removal of the plaster cast. The electrically evoked tetanic tensions at 10 Hz and 20 Hz did not change significantly (P greater than 0.1) during immobilization, but the 50 Hz tetanic tension (Po50) and maximal voluntary contraction (MVC) were reduced (p less than 0.05). The fall in Po50 and MVC was associated with 10% decrease in the estimated muscle (plus bone) cross-sectional area. The relative (%) change in Po50 and MVC following immobilization was related to the initial physiological status (as indicated by the response of the triceps surae to a standard fatigue test prior to immobilization) of the muscle. The rate of rise and recovery fall of the tetanus were slightly but significantly (p less than 0.01) reduced on day 7 of immobilization, but thereafter remained constant. The isokinetic properties of the triceps surae as reflected in the measured torque/velocity relation of the muscle in 4 subjects did not change significantly if account was taken of the slight degree of atrophy present following immobilization.(ABSTRACT TRUNCATED AT 250 WORDS)

Detection of methicillin-resistant Staphylococcus epidermidis.

To determine whether methods suggested for detecting methicillin-resistant Staphylococcus aureus apply equally to methicillin-resistant Staphylococcus epidermidis, 135 S. epidermidis isolates were tested by the Vitek AMS gram-positive susceptibility card (Vitek Systems, Inc., Hazelwood, Mo.) and by modifications of agar screen, disk diffusion, and microdilution methods. Modifications included 24- versus 48-h incubation, unsupplemented versus 2% NaCl-supplemented broth, and standard versus direct inoculum. At 24 h, the highest number of resistant strains, 59, was detected by oxacillin (1 microgram) disk diffusion. At 48 h, three additional strains were judged resistant. With one exception, results for oxacillin disk diffusion and agar screen were equivalent at 24 and 48 h. Vitek detected 50 resistant strains. Significantly fewer resistant strains were detected at 24 h by methicillin disk diffusion (5 micrograms) and methicillin microdilution with 2% NaCl. For oxacillin microdilution, neither 2% NaCl supplementation nor the method of inoculum preparation significantly affected the results. Oxacillin microdilution with cation- rather than non-cation-supplemented broth detected significantly fewer (n = 33) resistant strains at 24 h; 51 were resistant at 48 h. To detect methicillin-resistant S. epidermidis, a direct inoculum with either 24-h oxacillin disk diffusion and reincubation of intermediate strains for an additional 24 h or 24-h oxacillin agar screen and reincubation of strains with no growth for a total of 48 h is recommended.

Predictive value of serologic tests for syphilis in otology.

Otologic syphilis (luetic inner ear disease) usually is diagnosed by positive serologic tests and by exclusion of other possible causes. Because the FTA-ABS for syphilis is exquisitely sensitive in all but early primary cases, a positive FTA-ABS result and coincident inner ear disease often are thought to be diagnostic of syphilitic inner ear disease. The result is a management dilemma: are there false-positive results in misdiagnosed cases? Over 4 years, the authors performed a prospective study with time-matched controls to determine the predictive value of serologic tests and prevalence of syphilis in otology. Thirty-one cases of otologic syphilis were diagnosed in 5,439 new (different) patients with otologic complaints. In the geographic area studied, this prevalence (570/100,000) was 25-fold greater than that of all reported cases of syphilis in the general population (22.7/100,000). The defined sensitivity of the FTA-ABS (100%) was nearly twofold greater than the measured sensitivity of the rapid plasma reagin (RPR, 55%) in otologic syphilis. Specificities were comparable; therefore, a positive FTA-ABS had higher predictive value than a positive RPR. The prevalence-related predictive value of a positive FTA-ABS (22%) was more than twice that of the RPR (9%) in otology. The predictive value of a positive FTA-ABS in otology was 11-fold greater than that of the FTA-ABS in the general population (2%). Therefore, in suspect cases the FTA-ABS should be used to screen for otologic syphilis in an otologic practice. At a prevalence of 570 cases in 100,000 patients, only 22% of otologic patients with positive FTA-ABS results actually have otologic syphilis. Because disease morbidity can be far worse than treatment morbidity, however, positive results should be considered true-positives to avoid misdiagnosis in potentially infected patients. In suspect cases with positive FTA-ABS, therefore, treatment should be recommended unless specific contraindications exist.