Improvement of a wind-tunnel sampling system for odour and VOCs

Wind-tunnel systems are widely used for collecting odour emission samples from surface area sources. Consequently, a portable wind-tunnel system was developed at the University of New South Wales that was easy to handle and suitable for sampling from liquid surfaces. Development work was undertaken to ensure even air-flows above the emitting surface and to optimise air velocities to simulate real situations. However, recovery efficiencies for emissions have not previously been studied for wind-tunnel systems. A series of experiments was carried out for determining and improving the recovery rate of the wind-tunnel sampling system by using carbon monoxide as a tracer gas. It was observed by mass balance that carbon monoxide recovery rates were initially only 37% to 48% from a simulated surface area emission source. It was therefore apparent that further development work was required to improve recovery efficiencies. By analysing the aerodynamic character of air movement and CO transportation inside the wind-tunnel, it was determined that the apparent poor recoveries resulted from uneven mixing at the sample collection point. A number of modifications were made for the mixing chamber of the wind-tunnel system. A special sampling chamber extension and a sampling manifold with optimally distributed sampling orifices were developed for the wind-tunnel sampling system. The simulation experiments were repeated with the new sampling system. Over a series of experiments, the recovery efficiency of sampling was improved to 83-100% with an average of 90%, where the CO tracer gas was introduced at a single point and 92-102% with an average of 97%, where the CO tracer gas was introduced along a line transverse to the sweep air. The stability and accuracy of the new system were determined statistically and are reported.

Development of odour assessment criteria in New South Wales and application of the criteria for the assessment of a major public works project

The introduction of the forthcoming Australian and New Zealand standard on odour measurement has led to the review of odour regulation in most Australian states. In New South Wales the regulator has drafted an odour impact assessment policy for point source emissions. The policy is based on the new odour measurement standard and defines regulatory dispersion modelling procedures. The New South Wales odour assessment policy was initially drafted on the basis of a literature review and has since been developed in consultation with various industry and government groups, including sewerage authorities. The policy, while still officially regarded as a draft, has already been used as the basis for the assessment of a number of sewerage projects that have been characterised by point source emissions. The application of modelling-based assessment procedures requires careful judgement concerning the selection of input data and close scrutiny on behalf of the assessor. This paper examines the assumptions underlying the development of the New South Wales draft odour assessment policy and draws important universal lessons from its application for the assessment of a major sewerage project. The introduction of peak to mean factors based on one second nose response times has been controversial and alternative procedures are proposed.

Airway complications following pediatric lung and heart-lung transplantation

Obstruction at the airway anastomosis is a recognized complication of adult heart-lung transplantation (HLT) and lung transplantation (LT). Data for pediatric transplantation have been scarce. We reviewed our experience in pediatric HLT and LT to determine the frequency of airway complications and to document the therapeutic modalities used for their treatment. Fifty-three patients (median age: 13.8 yr; range: 1.3 to 28.2 yr) underwent HLT (n = 25), SLT (n = 3), DLT (n = 25), or repeat DLT (n = 3) and survived for more than 72 h. Major anastomotic airway complications requiring intervention affected one of the 25 HLT (4%) and seven of the 28 LT (SLT + DLT) patients (25%) (p = 0.05). Four patients with granulation tissue occluding the airway were treated with forceps resection, laser ablation, or balloon dilatation. Three patients with fibrotic strictures received silicone stents, laser ablation, or balloon dilatation. Two patients with bronchomalacia or diffuse stricture below the anastomosis underwent metal stent placement. Five of seven patients who were treated for anastomotic complications had satisfactory relief of airway obstruction. As compared with previously studied adults, pediatric heart-lung transplant recipients had the same or a lower frequency, and pediatric lung transplant recipients had a higher frequency of major anastomotic airway complications. A variety of treatment modalities were necessary to achieve adequate relief of airway obstruction.

American Orthopaedic Foot and Ankle Society shoe survey of diabetic patients

A one-page written survey was completed by 402 randomly selected patients with diabetes in five cities during a scheduled visit to their endocrinologist. Patients averaged 61.5 years of age and had been diagnosed with diabetes for 27.3 years. This study suggests that approximately 25% of adults with diabetes are at risk for developing foot ulcers, the precursor to deep infection leading to lower limb amputation. The goal at the inception of this project was to obtain benchmark data on the current level of prophylactic foot care being provided to adult patients with diabetes. The results of this survey suggest that most individuals with diabetes and their physicians are aware of potential diabetic foot morbidity, yet very few take advantage of prophylactic protective footware. Even fewer are presently taking advantage of benefits established through the Medicare Therapeutic Foot Bill. This survey highlights a substantial opportunity for improvement in the long-term care of individuals with diabetes.

Chylothorax and chylopericardium: a complication of a central venous catheter

This article describes a rare and severe complication of central venous catheterization, namely extensive thrombosis within the venous system of the chest resulting in bilateral chylothorax and chylopericardium. The complication resolved with drainage, catheter removal, and low molecular weight heparin therapy.

Partial splenic embolization for treatment of disseminated intravascular coagulation in lymphangiomatosis

A 1-year-old boy presented with pericardial effusion, pulmonary infiltrates, and disseminated intravascular coagulation; lung biopsy indicated pulmonary lymphangiomatosis. He did not respond to medical therapy and was a poor surgical candidate; therefore, he underwent partial splenic embolization. The procedure resulted in a complete disappearance of the DIC and marked improvement in his cardiorespiratory status. He continues to thrive and is transfusion-independent 2 years after the procedure.

Intravenous ondansetron in established postoperative emesis in children. S3A-381 Study Group

BACKGROUND

In pediatric postsurgical patients, postoperative vomiting is a common occurrence that can delay recovery and result in unplanned hospital admissions after outpatient surgery. This randomized, double-blind, placebo-controlled, multicenter study evaluated the efficacy and safety of ondansetron in the control of established postoperative emesis in outpatients aged 2-12 yr.

METHODS

Screened for the study were 2,720 ASA physical status 1-3 children undergoing outpatient surgery during general anesthesia, which included nitrous oxide. Children experiencing two emetic episodes within 2 h of discontinuation of nitrous oxide were given intravenous ondansetron (n = 192; 0.1 mg/kg for children weighing < or = 40 kg; 4 mg for children weighing > 40 kg) or placebo (n = 183).

RESULTS

The proportion of children with no emetic episodes and no use of rescue medication was significantly greater (P < 0.001) in the ondansetron group compared with placebo for both 2- and 24-h periods after study drug administration (78% of the ondansetron group and 34% of the placebo group for 2 h; 53% of the ondansetron group and 17% of the placebo group for 24 h). Among patients with at least one emetic episode or with rescue medication use, the median time to onset of emesis or rescue was 127 min in the ondansetron group compared with 58 min in the placebo group (P < 0.001). The median time from study drug administration until discharge was significantly shorter (P < 0.01) in the ondansetron group (153 min, range 44-593 min) compared with the placebo group (173 min, range 82-622 min). The incidence of potentially drug-related adverse events was similar in the ondansetron (3% of patients) and the placebo (4% of patients) groups.

CONCLUSION

A single dose of ondansetron (0.1 mg/kg up to 4 mg) is effective and well tolerated in the prevention of further episodes of postoperative emesis in children after outpatient surgery. Administration of ondansetron also may result in a shorter time to discharge.

Osteoid osteoma: percutaneous excision using a CT-guided coaxial technique

OBJECTIVE

We describe a coaxial technique for percutaneous, CT-guided removal of osteoid osteoma in children.

SUBJECTS AND METHODS

The study included eight children aged 3 years to 15 years 9 months who had signs and symptoms of osteoid osteoma. The diagnoses were confirmed by CT scans. Seven of nine lesions were removed manually with a coaxial technique and a trephine. Power tools were added to the technique in the other two cases. Removal of the nidus was confirmed by postprocedural CT scans and by histologic examination.

RESULTS

All CT-guided excisions were technically successful, and only one minor complication occurred. One recurrence at 13 months was successfully treated percutaneously.

CONCLUSION

CT-guided coaxial removal of osteoid osteoma is a safe and effective treatment. Increasing experience and the use of power tools in selected cases helps to shorten the procedure.

Intervention in the critically ill patient

In summary, interventional techniques are well-established and offer safe and effective alternatives for management of patients in the intensive care unit or other setting. It is likely that the radiologist will become more involved in the management of ill children and adults. It is hoped that this will reduce the need for opened surgical procedures, reduce the complexity of surgery, and provide treatment options for complications.

Investigations into the fat pads of the sole of the foot: anatomy and histology

Anatomical, histological, and histochemical studies were performed on normal and abnormal fat pads of the sole of cadaver feet. The fat pads were found to contain a significant nerve and blood supply separate from that to the surrounding musculature and skin. Pacinian corpuscles and free nerve endings within the fat were identified. Histological analysis indicated a meshwork of fibroelastic septae arranged in a closed-cell configuration. The mechanical consequences of this organization are discussed in the context of the weightbearing role of the fat pads of the feet. Alterations seen in dysvascular or senescent feet are consistent with the hypothesis that the septal anatomy of the fat pads is central to their cushioning function.

Aging of diabetic and nondiabetic skin fibroblasts in vitro: life span and sequential growth curves

Skin fibroblasts from age-matched normal and juvenile diabetic (IDDM) subjects were studied throughout their life span in vitro. The number of mean population doublings (MPD) attained at senescence was determined. Sequential 5-day growth curves were constructed. Normal cells were compared to cells from diabetics with recent onset of disease, 1-5 years, 6-10 years, and greater than 10 years of insulin therapy. A trend of decreasing MPD in vitro with increasing duration of diabetes in vivo was found. The growth potential of all cells (sequential growth curves) decreased with increasing time in vitro. The confluent density (Day 5) of diabetic (10 years' duration) cells was significantly lower than that for normal cells at Stage 2 of growth (passage 6-10). The in vitro aging of cells from diabetics (recent onset) was essentially the same as that of normal cells.

Research and practice in the treatment of insulin-dependent diabetes: a survey of 53 pediatric diabetologists

New techniques are available for the treatment of children with insulin-dependent diabetes mellitus. These include more intensive methods of insulin delivery by multiple daily injections or continuous subcutaneous infusion by portable pumps combined with patient self-monitoring of blood glucose. Long-term diabetic control can be evaluated by measurement of glycosylated hemoglobin, HbA1 or HbA1c. Pediatric practitioners may be in doubt as to the extent to which these techniques should be incorporated into their own practices. In order to provide some guidance in this quandary, the treatment practices as of June 1982, of 53 physicians with a special interest in the treatment of diabetic children were surveyed by questionnaire. The respondents estimated that they cared for 12,350 diabetic patients less than 19 years of age. Among their patients, 72% received twice-daily injections of insulin, 3% received three or more injections daily, and only 195 patients (2.7% of the total) were treated with insulin pumps. Among patients older than 10 years of age, 50% performed self-monitoring of blood glucose four times daily on one or more days per week and 32% of these patients did so daily. Two thirds of the patients utilized glucose oxidase-impregnated strips for blood glucose estimation and the remainder used reflectance meters. Essentially all respondents utilized glycosylated hemoglobin to evaluate quality of control. The mean number of determinations was 3.8 per year. Reasons for introducing pump therapy or discontinuing its use, glycemic targets for pump patients, and experience with utilization of the pump are described.(ABSTRACT TRUNCATED AT 250 WORDS)