Screening, assessment and management of perioperative malnutrition: a survey of UK practice.

BACKGROUND: Perioperative malnutrition is common and is associated with increased mortality, complications and healthcare costs. Patients having surgery for cancer and gastro-intestinal disease are at particular risk. It is a modifiable pre-operative risk factor and perioperative clinicians are well placed to identify those at risk and instigate interventions shown to improve outcome. Thus, we conducted a survey of Perioperative Medicine Leads with the aim of assessing the current provision of nutritional screening and intervention pathways in the UK. METHODS: Perioperative Medicine Leads registered with the Royal College of Anaesthetists were asked to complete an online survey exploring current practice in screening, assessment and management of malnutrition in the perioperative period. The survey included a mixture of open and closed questions, graded response questions and options for free text. Where a response was not received, departments were phoned directly and e-mails sent to non-responders. RESULTS: We received 121 completed questionnaires from 167 Perioperative Medicine Leads (response rate of 72.5%). Seventy respondents (57.9%) reported using the Malnutrition Universal Screening Tool to screen patients; however, only 61 (50.4%) referred patients at nutritional risk onto a dietitian. Sixty (49.6%) lacked confidence in local ability to identify and manage malnutrition perioperatively, with 28 (23.1%) reporting having a structured pathway for managing malnourished patients. One hundred eleven respondents (91.7%) agreed that malnutrition impacts on quality of life after surgery and 105 (86.8%) felt adopting a standard protocol would improve outcomes for patients. Those reporting a lack of confidence in dealing with malnutrition perioperatively cited a lack of organisational support, patients being seen too close to surgery and lack of clarity around responsibility as key reasons for difficulties in managing this group of patients. CONCLUSIONS: Malnutrition in the perioperative period is a modifiable risk factor which is common and results in increased morbidity for patients and increased cost to healthcare systems. This survey highlights areas of practice where perioperative clinicians can improve the assessment and management of patients at nutritional risk prior to elective surgery.

Self-diffusion in two-dimensional quasimagnetized rotating dusty plasmas.

The self-diffusion phenomenon in a two-dimensional dusty plasma at extremely strong (effective) magnetic fields is studied experimentally and by means of molecular dynamics simulations. In the experiment the high magnetic field is introduced by rotating the particle cloud and observing the particle trajectories in a corotating frame, which allows reaching effective magnetic fields up to 3000 T. The experimental results confirm the predictions of the simulations: (i) superdiffusive behavior is found at intermediate timescales and (ii) the dependence of the self-diffusion coefficient on the magnetic field is well reproduced.

Dusty plasma cavities: Probe-induced and natural.

A comprehensive exploration of regional dust evacuation in complex plasma crystals is presented. Voids created in three-dimensional crystals on the International Space Station have provided a rich foundation for experiments, but cavities in dust crystals formed in ground-based experiments have not received as much attention. Inside a modified Gaseous Electronics Conference rf cell, a powered vertical probe was used to clear the central area of a dust crystal, producing a cavity with high cylindrical symmetry. Cavities generated by three mechanisms are examined. First, repulsion of micrometer-sized particles by a negatively charged probe is investigated. A model of this effect developed for a dc plasma is modified and applied to explain experimental data in rf plasma. Second, the formation of natural cavities is surveyed; a radial ion drag proposed to occur due to a curved sheath is considered in conjunction with thermophoresis and a flattened confinement potential above the center of the electrode. Finally, cavity formation upon increasing the probe potential above the plasma floating potential is justified by a combination of ion drag and sheath edge modification. The cavities produced by these methods appear similar, but each is shown to be facilitated by fundamentally different processes.

Vertical-probe-induced asymmetric dust oscillation in complex plasma.

A complex plasma vertical oscillation experiment which modifies the bulk is presented. Spherical, micron-sized particles within a Coulomb crystal levitated in the sheath above the powered lower electrode in a GEC reference cell are perturbed using a probe attached to a Zyvex S100 Nanomanipulator. By oscillating the probe potential sinusoidally, particle motion is found to be asymmetric, exhibiting superharmonic response in one case. Using a simple electric field model for the plasma sheath, including a nonzero electric field at the sheath edge, dust particle charges are found by employing a balance of relevant forces and emission analysis. Adjusting the parameters of the electric field model allowed the change predicted in the levitation height to be compared with experiment. A discrete oscillator Green's function is applied using the derived force, which accurately predicts the particle's motion and allows the determination of the electric field at the sheath edge.

Four decades of conjoined twins at Red Cross Children's Hospital--lessons learned.

Conjoined twins represent a rare but fascinating congenital condition, the aetiology of which remains obscure. Over the past four decades, the paediatric surgeons at Red Cross Children's Hospital have been involved in the management of 46 pairs of conjoined twins, of which 33 have been symmetrical and 12 asymmetrical. Seventeen symmetrical twins have undergone separation with 22 children (65%) surviving; all of the live asymmetrical twins survived separation. We describe the important features of this unique cohort, outline our approach to management and present the results of this approach. We consider some of the ethical and moral dilemmas we have confronted, and discuss the prenatal diagnosis, obstetric implications and postnatal care of these children, including the relevant investigations and anaesthetic and surgical management. Specific aspects related to the cardiovascular system, hepatobiliary and gastrointestinal tracts, urogenital tract, central nervous system and musculoskeletal system are highlighted.

Human osteoblast-like cells and osteosarcoma cell lines synthesize macrophage inhibitory protein 1alpha in response to interleukin 1beta and tumour necrosis factor alpha stimulation in vitro.

Recent investigations have demonstrated that macrophage inhibitory protein 1alpha (MIP-1alpha) plays a critical role in haematopoiesis. In part, MIP-1alpha limits the differentiation of early haematopoietic cells, thereby ensuring that sufficient quantities of blood precursors are available to meet haematopoietic demands. MIP-1alpha is produced by cells of the marrow microenvironment (marrow stromal cells) in response to a variety of stimuli, including interleukin 1beta (IL-1beta) and tumour necrosis factor alpha (TNF-alpha). Our recent investigations demonstrated that normal human osteoblast-like cells (HOBs) maintain the early phenotype of haematopoietic precursors, like other members of the bone marrow stroma. Although the precise molecular mechanisms for these observations have not been determined, the production of MIP-1alpha remains one such possibility. In the present study, we investigated whether cells of the osteoblast lineage under basal, IL-1beta and/or TNF-alpha stimulation produce MIP-1alpha. We observed that IL-1beta and TNF-alpha stimulated HOBs and human osteosarcoma cells to rapidly express MIP-1alpha mRNA and to secrete large quantities of the protein. MIP-1alpha mRNA and protein was not, however, detected under basal conditions. Perhaps more importantly, enriched human CD34+ bone marrow cells in co-culture may be capable of stimulating the expression of MIP-1alpha mRNA by HOBs in vitro. These findings suggest that human osteoblast-like cells may produce MIP-1alpha in vivo to support haematopoiesis at sites where osteoblasts and haematopoietic cells are closely associated.

Pathways of economic influence on adolescent adjustment.

An important part of a science aimed at the prevention of human dysfunction involves the development of empirically based models that identify processes of risk for or protection from emotional distress or behavioral problems over time. The present study developed and evaluated such a model that proposed two pathways through which family economic pressure was expected to influence change in adolescent internalizing symptoms (depression and anxiety) during the period from the eighth to the tenth grades. A total of 377 rural families in a midwestern state provided data for the analyses. The results were generally consistent with the conceptual model in that family economic pressure increased adolescent perceptions of family economic hardship, which, in turn, reduced the adolescent's sense of control or mastery over time. Lowered mastery was associated with increases in emotional distress. Also consistent with the model, prior levels of mastery appeared to reduce the magnitude of economic stress experienced by the adolescent, whereas prior emotional distress intensified the economic stress process. Although gender differences were found in these processes, the overall pattern of results suggests that girls and boys are both at risk for internalizing problems when families experience economic pressure. Implications of the findings for the development of effective preventive interventions with financially stressed families in rural areas are discussed.

Arthroscopic versus open distal clavicle resection: a biomechanical analysis on a cadaveric model.

A fresh cadaver shoulder model was used to evaluate the difference in joint laxity between arthroscopic and open distal clavicle resection procedures. Twelve shoulders were mounted in a load frame that allowed compressive loading of the distal clavicle into the acromion. Specimens were loaded to 100 N (20 N/sec) while load and deformation data were recorded for three conditions: (1) intact, (2) 5-mm closed resection, and (3) 10-mm open resection. The displacement at the 100-N load and the stiffness of the load/displacement curves were compared for the intact, arthroscopic, and open procedures. Significant differences (ANOVA, P< or =.05) in displacement and stiffness were observed between the intact joint and both surgically resected joints. No significant differences were observed between the two surgically resected joints. The amount of bone removed arthroscopically was sufficient to prevent further bony contact in the axially loaded acromioclavicular joint.

Determination of fixation strength of large-diameter interference screws.

Small-diameter interference screws are a widely used method of securing bone-tendon grafts during anterior cruciate ligament reconstructive procedures. Recent reports document tunnel widening and subsequent loss of fixation, leading to a need for alternative fixation methods. In cadaver tissue, the fixation strength of large-diameter (11-, 13-, and 15-mm) interference screws was tested and compared with that of clinically used 9-mm diameter screws. Patellar-tendon sections were fashioned into three grafts, each with bone plugs measuring 10 x 20 x 7.5 mm. Tunnels were created in the epiphyseal bone of the femurs and tibias, resulting in gap sizes of 4.5-, 6.5-, 8.5-, and 10.5-mm for the 9-, 11-, 13-, and 15-mm diameter screws, respectively. Grafts were pulled from the tunnel at a rate of 51 cm/min. Average fixation strengths were 276, 302, 328, and 328 N for the 9-, 11-, 13-, and 15-mm screws, respectively. No significant difference existed between the fixation strengths (ANOVA, P < or = .05).

Leg injuries.

Injuries in the leg span a broad spectrum of patient age and athletic level. Overuse injuries, such as medial tibial stress syndromes and stress fractures, tend to occur in the young athlete, whereas tennis leg usually occurs in the older population. With a few exceptions, most of these injuries can be successfully treated nonoperatively. Particularly with the young athlete, it is important to stress the necessity to rest and avoid activities that would compound the injury.

Optimal side plate fixation for unstable intertrochanteric hip fractures.

OBJECTIVES: To quantitatively determine the minimal screw number needed for stable side plate fixation to the femoral shaft in treating unstable intertrochanteric hip fractures. DESIGN: Laboratory/biomedics study. SETTING: Orthopaedic biomechanics laboratory. PATIENTS OR OTHER PARTICIPANTS: The convenience sample was made up of one saw bone, one steel pipe, and ten human cadaveric femur specimens. Human specimens were selected by ruling out pathology and excess osteopenia. Ten specimens were tested to completion. INTERVENTION: Telescoping hip screw and hip screw side plate secured with various numbered combinations of side plate screws. MAIN OUTCOME MEASURES: Decreases in tension experienced by all previously inserted screws when an additional screw was applied were recorded and labeled as "protection." RESULTS: Protection offered by a third screw on all previous screws was 787.3 newtons in the steel pipemodel, 71.2 newtons in the sawbone model, and 158.3 newtons in the human model (p < 0.005). A fourth bone screw did not decrease tension in previous screws by more than 11 newtons. The protective effect of the fourth screw on screw #3 increased with decreasing screw application torque by a maximum of 21.8 newtons (p < 0.005). CONCLUSION: This study suggests that three bone screws provide an optimal distribution of tensile forces. The insertional torque used to place screws, once screw-plate contact has been established, does not play a significant role in screw protection. Additional studies are needed to assess the role of cortical bone density, and cyclical loading and bending forces experienced by the side plate screws, before definite clinical recommendations can be made.

Infection around joint replacements in patients who have a renal or liver transplantation.

The results of thirty-five joint (hip or knee) replacements in nineteen patients who had an organ transplantation were retrospectively reviewed. The patients received a standard immunosuppressive induction regimen at the time of the transplantation and were maintained on a combination of prednisone, azathioprine, and cyclosporine A. All patients received antibiotics perioperatively, but antibiotic-impregnated bone cement was not used for any procedure. Six joint replacements, in three patients who were an average of 48.2 years old at the time of the arthroplasty, were performed before a renal transplantation. Twenty-four joint replacements, in fourteen patients who were an average of 40.9 years old at the time of the arthroplasty, were performed after an organ transplantation. Two patients, who were an average of 53.8 years old at the time of the arthroplasty, each had a joint replacement both before and after a liver transplantation (a total of five joint replacements). The average duration of follow-up from the first joint replacement was 8.8 years (range, one to twenty-three years). The Harris hip score or The Hospital for Special Surgery knee score was determined at the time of the latest follow-up examination. An infection developed around the implant in five patients who had had the joint replacement after a transplantation. The average interval from implantation of the prosthesis until detection of the infection was 3.4 years (range, one to six years). One patient who had a liver transplant was infected with Pseudomonas aeruginosa and another one was infected with Escherichia coli. One patient who had a renal transplant was infected with Staphylococcus epidermidis; one, with Enterococcus; and one, with Serratia marcescens. We found that patients who had a joint replacement after an organ transplantation had a very high risk of devastating infection. The rate of such infection was 19 per cent (five of twenty-seven joint replacements in sixteen patients).

An ultrasound method to evaluate polyethylene component wear in total knee replacement arthroplasty.

Evaluation of a painful total knee replacement has been limited to physical examination, aspiration, plain radiographs, and radionuclide studies. Visualization of the polyethylene tibial-bearing component without surgery has not been possible. Polyethylene wear is a well-recognized cause of total knee replacement failure. We have developed an ultrasound method to evaluate polyethylene insert shape and thickness with the ability to clearly demonstrate structural loss of plastic. Before clinical trials, a total knee replacement was cemented into a fresh cadaver knee. Ultrasound imaging of the polyethylene insert was performed in the longitudinal plane using a 10 MHz linear transducer. A characteristic bone/metal/polyethylene interface enabled recognition of the insert material from which its dimension was estimated. The entire perimeter of the liner, the metal tray, and the bone-metal interface was visualized. Five consecutive measurements at each location were performed on each of the 8-, 10-, and 12-mm polyethylene liners with the ultrasonographer blind to the insert thickness. Once removed, measurements were made directly on the liners adjacent to the marked points with an electronic caliper. Coefficient of variation (r2) ranged from 1.6% to 8.3% for the ultrasound measurements, and 0.26% to 1.5% for the caliper measurements. A plot of ultrasound versus caliper measurements allowed calculation of a linear equation, with r2 = 0.98, demonstrating high correlation between the two measurements. Our ultrasound measurements are accurate to 0.5 mm with a 95% confidence interval. Ultrasound is an accurate way to measure the dimensions of the polyethylene liner in total knee replacement arthroplasty. Early experiences with ultrasound evaluation prior to revision have been very encouraging for the evaluation of polyethylene wear, defects, and of prosthetic loosening.

Prescribing exercise for your patient.

The lack of exercise by most Americans is a major contributing factor to many chronic diseases. Physicians are now prescribing exercise for patients just as they would drugs. Compliance with any exercise program depends on realizing the needs and goals of the individual. The fundamental principles of an exercise prescription apply to all persons regardless of age, sex, or level of fitness. A systematic manipulation of the components of frequency, duration, intensity, and progression with periodic reevaluation allows the program to be individualized. The guidelines for the program should include all of the components of health-related physical fitness. These include cardiorespiratory endurance, body composition, muscular strength and endurance, and flexibility. A program for exercise should fit the lifestyle of the patient and be a life-long prescription.

Use of patellar allograft to reconstruct a patellar tendon-deficient knee after total joint arthroplasty.

A catastrophic complication after total knee arthroplasty (TKA) is rupture of the patellar tendon. Several techniques for treatment have been described, including cast immobilization with or without operative repair, the use of a semitendinosus, fascia lata, or hamstring tendon autogenous graft, the use of a Dacron 4-mm vascular graft (U.S. Catheter and Instrument, Glen Falls, NY), the use of bovine xenograft and even transplantation of an entire allograft extensor mechanism. Treatment results of patellar tendon rupture after TKA can be discouraging. Altered tissue quality secondary to connective tissue diseases, diabetes, rheumatoid arthritis, lupus erythematosus, secondary hyperparathyroidism, or concurrent steroid medications contributes to poor results. Additionally, no one treatment has provided consistent clinical success. Successful treatment of a patient with a ruptured patellar tendon after TKA using the bone-patellar tendon-bone allograft commonly used for anterior cruciate ligament reconstruction is reported.

Scapulothoracic anatomy for the arthroscopist.

Because endoscopic management has recently been introduced as treatment for painful subscapular snapping, we designed a cadaveric study to identify the boundaries of the scapulothoracic spaces and the relationship of important neurovascular structures to safe portal sites for arthroscopic surgery. We studied eight fresh, unembalmed cadaveric shoulders by anatomic dissection alone and eight fresh, unembalmed cadaveric shoulders by dissection after arthroscopy. We noted the following findings: (1) the scapulothoracic articulation has two triangular spaces, the serratus anterior space and the subscapularis space, that are divided obliquely by the serratus anterior muscle; (2) the boundaries of the larger serratus anterior space include the chest wall anteriorly, the serratus anterior muscle posteriorly, and the rhomboids medially; (3) the boundaries of the subscapularis space are the serratus anterior muscle anteriorly, the subscapularis muscle posteriorly, and the axilla laterally; and (4) a well-defined bursa occupies the serratus anterior space. Based on these findings, we recommend that portals for arthroscopic surgery should be inferior to the spine of the scapula and three to four finger-breadths from the vertebral border of the scapula (1) to avoid the neurovascular structures at the superomedial angle of the scapula, (2) to avoid the dorsosacpular nerve and artery, and (3) to prevent perpendicular orientation of the arthroscope to the lateral chest wall.