Premature coronary artery disease and early stage chronic kidney disease.

A 30 year old asymptomatic male with stage 3 chronic kidney disease (CKD) secondary to Focal Segmental Glomerulosclerosis was found to have features of CKD associated cardiomyopathy including left ventricular hypertrophy (LVH) and focal sub-endocardial scarring on cardiac magnetic resonance imaging. There was also a significantly raised CT coronary calcium score and evidence of non-flow limiting coronary artery disease (CAD) on a CT coronary angiogram. Early stage CKD is a major risk factor for cardiovascular risk causing myocardial hypertrophy and fibrosis and coronary artery atheroma. Cardiovascular risk begins to increase from an eGFR of around 75ml/min/1.73m2. The pathophysiology of cardiovascular disease in CKD is under investigation but to date, treatment options are limited. Blood pressure control and statins have the strongest supportive evidence.

A comparison of registration errors with imageless computer navigation during MIS total knee arthroplasty versus standard incision total knee arthroplasty: a cadaveric study.

Optimal component alignment in total knee arthroplasty has been associated with better functional outcome as well as improved implant longevity. The ability to align components optimally during minimally invasive (MIS) total knee replacement (TKR) has been a cause of concern. Computer navigation is a useful aid in achieving the desired alignment although it is limited by the error during the manual registration of landmarks. Our study aims to compare the registration process error between a standard and a MIS surgical approach. We hypothesized that performing the registration error via an MIS approach would increase the registration process error. Five fresh frozen lower limbs were routinely prepared and draped. The registration process was performed through an MIS approach. This was then extended to the standard approach and the registration was performed again. Two surgeons performed the registration process five times with each approach. Performing the registration process through the MIS approach was not associated with higher error compared to the standard approach in the alignment parameters of interest. This rejects our hypothesis. Image-free navigated MIS TKR does not appear to carry higher risk of component malalignment due to the registration process error. Navigation can be used during MIS TKR to improve alignment without reduced accuracy due to the approach.

Defining the errors in the registration process during imageless computer navigation in total knee arthroplasty: a cadaveric study.

Computer assisted arthroplasty was introduced as a means to optimally align implants in order to improve function and longevity. The error during the manual registration of landmarks and its effect on component alignment was investigated in this study. Five fresh frozen lower limbs were used and the registration process was performed five times by five surgeons. The error range of the mechanical axis of the femur in the coronal plane was 5.2 degrees of valgus to 2.9 degrees of varus whilst the transepicondylar axis error was 11.1 degrees of external to 6.3 of internal rotation. Those figures suggest that the registration error alone can have a significant effect on the alignment of the implant.

Computer-assisted navigation for the assessment of fixed flexion in knee arthroplasty.

BACKGROUND: Correction of a fixed flexion deformity is an important goal when performing total knee arthroplasty. The purpose of this study was to assess the accuracy of clinical assessment compared with imageless computer navigation in determining the degree of fixed flexion. METHODS: We performed navigation anatomy registration using 14 cadaver knees.The knees were held in various degrees of flexion with 2 crossed pins. The degree of flexion was first recorded on the computer and then on lateral radiographs. The cadaver knees were draped as they would be for a total knee arthroplasty, and 9 examiners were asked to clinically assess by visual observation the amount of fixed flexion.Three examiners repeated the process 1 week later. RESULTS: The mean error from the radiographs in the navigation group was 2.18 degrees (95% confidence interval [CI] 1.23 degrees -3.01 degrees) compared with 5.57 degrees (95% CI 4.86 degrees -6.29 degrees) in the observer group. The navigation was more consistent, with a range of error of -5 degrees to +5.5 degrees compared with -18.5 degrees to +17.5 degrees in the observer group. The observers tended to underestimate the amount of knee flexion (median error -4 degrees), whereas the navigation group was more evenly distributed (median error 0). The highest concordance coefficient was found between navigation and radiography (0.96). The concordance coefficient was 0.88 for the 3 surgeons who repeated the measurements 1 week later (mean error 3.5 degrees , range 15 degrees ). CONCLUSION: The use of computer navigation appears to be a more accurate method for assessing the degree of knee flexion, with a reduced range of error compared with clinical assessment. The use of computer-assisted surgery may therefore provide surgeons with the information required to more consistently restore full extension during total knee arthroplasty.

The reliability of radiographic assessment of femoral neck-shaft and implant angulation in hip resurfacing arthroplasty.

Fifteen sets of patient radiographs were analyzed by 3 different observers on 2 occasions. Each observer measured the femoral neck-shaft angles (NSAs) of the preoperative digital radiographs and stem-shaft angles (SSAs) of the postoperative radiographs. The effect of femur position on SSA measured by digital radiographs was also investigated using a resurfaced synthetic femur. Radiographs were taken with the synthetic specimen positioned in 10 degrees increments of either flexion or rotation. Measurement by digital radiographs proved less than optimal in assessing preoperative NSA but was better in assessing the postoperative component SSA. External rotation of 30 degrees and flexion of 40 degrees resulted in a clinically significant disparity in SSA measurements. Patient malposition during radiographic imaging can contribute to erroneous NSA and SSA results.

Distribution of 8-oxygenated leaf-surface flavones in the genus Ocimum.

Nine species of Ocimum (Lamiaceae) were surveyed for leaf-surface flavonoids by means of HPLC with diode array detection and atmospheric pressure chemical ionisation (APCI) mass spectrometry. The analysis revealed the presence of 23 different flavones, most of which were identified by comparing their UV and mass spectra with those of standards. Almost all taxa investigated contained flavones methoxylated in the 6- and 8-positions, such as nevadensin, xanthomicrol and gardenin B. The same taxa also produced flavones methoxylated in the 6-position but hydroxylated in the 8-position, including isothymusin (5,8,4'-trihydroxy-6,7-dimethoxyflavone), pedunculin (5,8-dihydroxy-6,7,4'-trimethoxyflavone) and a new flavone, 5,7,8-trihydroxy-6,4'-dimethoxyflavone, which was given the trivial name pilosin. This compound was isolated from O. americanum var. pilosum and also detected as a minor constituent in O. x citriodorum leaf extracts. Its molecular structure was elucidated by means of NMR spectroscopy. 8-Oxygenated flavones were absent only from O. lamiifolium. APCI mass spectrometry of the flavonoids revealed that the product ions formed by collision induced dissociation of the protonated molecule provided structural information about the substitution pattern of the A-ring. The chemotaxonomic and biogenetic implications of the results are discussed.

Nurse-led weaning from mechanical ventilation: where's the evidence?

BACKGROUND: Several authors have suggested clinical protocols as a means of shortening ventilation time and the important role of the nurse in reducing ventilation time has also been highlighted. Despite the many references in the literature to reducing weaning times using clinical protocols, it is not clear whether nurse-led weaning strategies hasten weaning from mechanical ventilation compared with physician-led care. OBJECTIVE: to systematically review the published literature to answer the question: Does nurse-led weaning from mechanical ventilation reduce duration of ventilation compared with doctor-led care? DATA SOURCES: MEDLINE, CINHAL, EMBASE, Cochrane Library, Best Evidence, hand search, expert opinion, controlled trials register. STUDY SELECTION: randomized controlled trials (RCTs) and cohort studies where nurses or respiratory therapists lead the weaning from mechanical ventilation; duration of ventilation must be stated. DATA EXTRACTION: performed by the author, who extracted data on statistical significance of the difference in duration of ventilation between control and trial groups, complication rates (such as reintubation) and mortality. DATA SYNTHESIS: statistical synthesis was not attempted but narrative synthesis was performed. RESULTS: only 1 randomized controlled trial and 2 cohort studies were found where nurses or respiratory therapists led weaning using a protocol. Two studies showed reduction in ventilation time without additional complications; the third study had the weakest evidence, because it was retrospective, and showed no difference between control and treatment groups. CONCLUSIONS: There is limited evidence suggesting that nurse-led weaning may reduce ventilation time; however, it is not clear whether it was the nurse-led aspect or the clinical protocol that produced the effect.

Our journey with clinical supervision in an intensive care unit.

In 1991, the nursing profession began to pursue the idea of reflective practice with vigour, despite little evidence that reflective practice improved nursing care (Burnard 1991; Hunt 1993). A small qualitative study on the experiences of nurses writing reflective journals was undertaken in the intensive care unit at Newham General Hospital. (A Price 1995). This highlighted the need for clear initial guidance and support when introducing reflective practice. It also demonstrated a lack of knowledge about reflection within the unit. During this time, a group of nurses who were interested in developing clinical supervision as a method of support for staff was formed. Kohner's (1994) definition of clinical supervision, adopted by the group after review of literature, makes it clear that this involves reflection on practice. Johns' (1993) Model of Structured Reflection was amended and used to promote in-depth analysis of situations, and journal writing was encouraged within the group. A continuing process of group clinical supervision was started, initially with the help of a facilitator experienced in it. On the basis of this experience, a strategy for implementation of clinical supervision in the intensive care unit was developed and put into action by the group members. Consideration of the progress and problems experienced leads to the conclusion that continuing staff motivation and commitment, and adequate time are essential for implementation of clinical supervision.

Osmolality affects ion and water fluxes and secretion in the ferret trachea.

Nonisosmolar solutions were placed in the lumen of the ferret trachea in vitro in an organ bath. Hyposmolar (150 mmol/kg) solutions progressively increased in osmolarity over 1 h. Increases in luminal concentration of impermeant blue dextran occurred only after 5 min, suggesting that the initial changes were due to ion rather than water fluxes. With hyperosmolar solutions the osmolarity decreased over 1 h with no change in blue dextran concentration, indicating that ion but not water fluxes were taking place. Cooling the preparation to 4 degrees C greatly reduced the osmolaity changes with hyperosmolar solutions and halved those with hyposmolar solutions, suggesting that active ion transport was involved. Hyposmolar (75-150 mmol/kg) and hyperosmolar (450-900 mmol/kg) solutions both increased albumin output into the lumen, but the response was prevented by cooling the trachea to 4 degrees C. Hyposmolar and hyperosmolar solutions both increased the output of lysozyme from glandular serous cells into the lumen. The response to hyposmolar solutions was stronger. Cooling the trachea abolished the lysozyme response to hyperosmolar solutions. Thus hypo- and hyperosmolar solutions promote ion transport in directions to restore isosmolarity. Both nonisosmolar solutions promote albumin movement by active transport across the mucosa and lysozyme secretion from submucosal glands, responses inhibited by tracheal cooling and therefore dependent on metabolically active processes.

Transport of albumin by the rabbit trachea in vitro.

The rabbit whole trachea was mounted in vitro in an organ bath containing Krebs-Henseleit (KH) solution. When the trachea was air filled there was no resting secretion and none was induced by methacholine (0.02 mM). Histology showed that the trachea has very few submucosal glands. When the trachea was filled with KH, with fluorescent bovine serum albumin in the surrounding KH solution, the rate of transport of albumin into the lumen was measured. Methacholine (0.02 mM) and phenylephrine (0.1 mM) more than doubled the output of albumin, and albuterol (0.1 mM) increased it more than fourfold. Cooling the preparation to 4 degrees C decreased the spontaneous output of albumin to less than one-half control and abolished the increase in output due to albuterol. Addition of sodium cyanide (1 mM) to the preparation abolished the increase in albumin transport due to albuterol. Serosal-to-mucosal transport of fluorescent dextran (mol wt 70,000) was less than one-third that of albumin and was not enhanced by methacholine, phenylephrine, or albuterol. Lysozyme output, an index of serous cell secretion, was barely detectable in controls and was not enhanced by any of the drugs. We conclude that the rabbit trachea has no measurable submucosal gland secretion and that it can actively transport albumin into the lumen via the epithelium. The transport rate is enhanced by methacholine, phenylephrine, and especially by albuterol.