A methodology for the assessment of rehabilitation success of post mining landscapes--sediment and radionuclide transport at the former Nabarlek uranium mine, Northern Territory, Australia.

Protection of the environment post-mining is an important issue, especially where runoff and erosion can lead to undesirable material leaving post-mining landscapes and contaminating surrounding land and watercourses. Methods for assessment of the environmental impact and long-term behaviour of post-mining landforms based on scientific methodology are needed especially where field data are absent or poor. An appraisal of the former Nabarlek uranium mine was conducted to assess the site from a soil erosion perspective as part of an independent evaluation of overall rehabilitation success. Determination of the gross erosion occurring, sediment discharge to Cooper Creek and the resultant sediment associated radionuclide load in Cooper Creek were the primary objectives of the study. These objectives were achieved through the application of several models using parameter values collected from the site. The study found that the area containing the mill tailings repository is extremely stable and meets the guidelines established for long-term storage of uranium mill tailings. Most other areas on the site are stable; however there are some areas with a high sediment loss. Sediment concentration in Cooper Creek, which drains the site, was found to be within the Australian water quality guidelines for fresh water, however sediment concentrations in tributaries were found to exceed recommended levels. Radionuclide determinations on soil samples showed that the highest specific activities (Bq kg-1) were present on a small (0.44 ha) area with a relatively high erosion rate. This small area contributed the majority of the estimated flux to Cooper Creek of uranium-series radionuclides sorbed or structurally incorporated to eroded soil particles sourced from the mine site. This study provides a methodology for assessment of the erosional stability of such a landscape and consequent impact on water quality, using extensive field data and readily available and well known models and methodologies.

Diaphragm injury in individuals with airflow obstruction.

The purpose of this study was to describe the nature of diaphragm injury, to quantify the injury and number of macrophages at the light microscopic level, and to determine their association with airflow obstruction in humans. Partial-thickness diaphragm biopsies were obtained from 21 subjects going for thoracotomy surgery (FEV(1): 74 +/- 34% predicted; range: 16 to 122% predicted). Cross sections cut from frozen diaphragm were processed with H&E or processed for immunohistochemistry using the monoclonal antibody Ber-MAC3 (DAKO Corp., Carpinteria, CA) to label macrophages. Area fractions (A(A)) or the proportions of the cross- sectional area were determined by point counting all viable fields of H&E-stained diaphragm cross sections. A(A) were 66.2 +/- 9.0% for normal muscle, 17.6 +/- 7.2% for abnormal muscle, and 16.3 +/- 4.2% for connective tissue. Percent predicted FEV(1) was inversely related to the A(A) of abnormal muscle (r = -0.53, p < 0.01) and directly related to the A(A) of normal muscle (r = 0.37, p < 0.05). The number of macrophages was not related to % predicted FEV(1) (mean +/- SD: 0.41 +/- 0.18/fiber; 52 +/- 19/mm(2)). We conclude that increasing severity of airflow obstruction is associated with an increased A(A) of abnormal diaphragm and a decreased A(A) of normal diaphragm.

Severe methemoglobinemia from topical anesthetic spray: case report, discussion and qualitative systematic review.

Few health care professionals realize that topical anesthetic spray can cause methemoglobinemia. We describe a 56-year-old woman who was transferred to our emergency department when severe cyanosis and chest pain developed after administration of topical oropharyngeal benzocaine and lidocaine during outpatient endoscopy. Investigations revealed a methemoglobin level of 51%. Despite rapid diagnosis and treatment with methylene blue, pulmonary edema consistent with adult respiratory distress syndrome developed, endotracheal intubation was required, and the patient suffered a lengthy course in the intensive care unit. This article presents a detailed discussion of the pathophysiology, diagnosis and treatment of methemoglobinemia, as well as a qualitative systematic review of the English literature on methemoglobinemia induced by topical anesthetic. The implications of this condition for emergency physicians are also outlined.

Role of CO diffusing capacity during exercise in the preoperative evaluation for lung resection.

We conducted a prospective study to evaluate whether lack of an adequate increase in diffusing capacity for carbon monoxide (DL(CO)) during exercise is associated with a greater postoperative complication rate after lung resection. We used the three-equation method (3EQ-DL(CO)), a modification of the single breath DL(CO) technique to determine DL(CO) during exercise in 57 patients undergoing lung resection at Vancouver General Hospital from October 1998 to May 1999. 3EQ-DL(CO) was determined during steady-state exercise at 35% and 70% of the maximal workload reached in a progressive exercise test. Maximal oxygen uptake (VO(2)max), DL(CO) at rest, and the increase in DL(CO) during exercise were compared in relation to postoperative complications. Patients with complications had lower resting values of DL(CO) (R-DL(CO)), a smaller increase in DL(CO) from rest to 70% of maximal workload expressed as a percent of the predicted DL(CO) at rest ([70% - R]-DL(CO)%), and a lower VO(2)max than did patients without complications. Results suggested that (70% - R)-DL(CO)% was the best preoperative predictor of postoperative complications; a cutoff limit of 10% was the best index to identify complications, yielding a complication rate of 100% in patients with (70% - R)-DL(CO)% < 10% as compared with a complication rate of 10% in patients with (70% - R)-DL(CO)% >/= 10% (sensitivity = 78%, specificity = 100%). Patients who do not increase their DL(CO) sufficiently during exercise ([70% - R]-DL(CO)% < 10%) have a greater complication rate after lung resection.

Surgical management of adenocarcinoma of the cardia.

BACKGROUND: The incidence of adenocarcinoma of the cardia is increasing. The surgical management remains controversial. The present study reviews our experience with surgically resected adenocarcinoma of the cardia. METHODS: A retrospective review of 153 cases of surgically resected adenocarcinoma of the cardia was performed. Preoperative radiotherapy was used in 31 patients. The surgical approach, morbidity, mortality, impact of preoperative radiotherapy, and survival were determined. RESULTS: The type of resection performed was a transhiatal esophagogastrectomy in 78%, a transthoracic esophagogastrectomy in 21%, and a transabdominal esophagogastrectomy in 1%. The in-hospital mortality rate was 4%. The frequency of complications was not associated with the use of preoperative radiotherapy or surgical approach. The 1-year (61%), 2-year (38%), 3-year (23%), and 5-year (16%) survival were not affected by the use of preoperative radiotherapy or surgical approach. Survival was significantly associated with stage and the presence of lymph node metastasis. CONCLUSIONS: Adenocarcinoma of the cardia is associated with a poor long-term prognosis. The long-term survival does not appear to be affected by the use of preoperative radiotherapy or by surgical approach.

Estimation of analogue pre-filtering characteristics for CORSA standardisation.

This paper is concerned with devising a standard procedure for determining the gain and phase responses of the analogue filters used to pre-process pulmonary signals prior to their digitisation. The customary high-pass filtering, in particular, will strongly affect the time-domain wave-shapes of digitised signals and this must be taken into account when analysing the signals. Several means of determining the effect of the high-pass filtering are investigated and a measurement procedure is proposed which may be easily carried out using simple laboratory equipment.

Pulmonary nodules: differential diagnosis using 18F-fluorodeoxyglucose single-photon emission computed tomography.

OBJECTIVE: The objective of this study was to prospectively evaluate the feasibility and efficacy of single-photon emission computed tomography (SPECT) with 18F-fluorodeoxyglucose (FDG) for differentiating malignant from benign pulmonary nodules. SUBJECTS AND METHODS: Twenty-six patients with 28 radiologically indeterminate focal pulmonary lesions were examined. Fasting patients were injected with 5 MBq/kg of FDG (maximum dose, 370 MBq). Imaging was performed with dual-head SPECT cameras equipped with 511-keV collimators. RESULTS: Seventeen of 21 pathologically malignant nodules showed FDG uptake on SPECT imaging (sensitivity, 81%). None of the seven benign modules showed uptake (specificity, 100%). SPECT imaging with FDG was positive in all 16 malignant nodules that were larger than or equal to 2 cm in diameter. However, only one (20%) of five nodules smaller than 2 cm in diameter showed positive on SPECT imaging. CONCLUSION: Using current technology, we found FDG SPECT imaging useful for distinguishing benign from malignant pulmonary nodules that were larger than or equal to 2 cm in diameter. However, because of the relatively low sensitivity of SPECT, smaller malignant nodules were not adequately revealed.

Gastrointestinal function following esophagectomy for malignancy.

BACKGROUND: The frequency and causes of gastrointestinal complications following esophagectomy for malignancy are unknown. PATIENTS AND METHODS: We reviewed 295 esophagectomies performed for malignancy between January 1980 and September 1994 in order to determine the frequency and causes of early and late gastrointestinal complications. RESULTS: Compared to transhiatal and left thoracoabdominal esophagectomies, esophagectomies carried out through a right posterolateral thoracotomy with cervical esophagogastric anastomosis had a higher incidence of delayed gastric emptying (11%), pneumonia (26%), and hospital death (9%). The same operation had a higher incidence of gastroesophageal reflux (20%) and dysphagia requiring esophageal dilatation (53%). We found no independent effect of gastric drainage procedures, feeding jejunostomy, preoperative radiotherapy, pathology, or age on these outcomes. Women had no operative mortality, but a higher incidence of gastroesophageal reflux and diarrhea following esophagectomy. CONCLUSIONS: Surgical techniques aimed at improving gastric emptying following esophagectomy for cancer should improve operative morbidity and mortality.

Transhiatal esophagectomy for carcinoma of the esophagus and cardia. Experience with 160 cases.

We reviewed our experience from 1979 to 1990 with 160 cases of transhiatal esophagectomy for carcinoma of the lower esophagus and cardia to evaluate trends in patient selection, management, and outcome. Patients treated in the past 6 years (n = 110) and those treated before 1985 (n = 50) were similar in terms of age and sex distribution, medical history, and weight loss. The majority of tumors seen were adenocarcinoma, with patients in the latter group having significantly lower stages. Significant decreases in anesthetic time, units of blood transfusions, chest tube insertions, length of postoperative ventilation, incidence of postoperative pneumonia, and length of hospital stay were seen during the past 6 years. Wound infections increased significantly during the same period. The decrease in the 30-day mortality rate from 6% to 0.9% was not significant. Survival rates did not differ between groups, with overall rates of 62%, 40%, and 21% at 1, 2, and 5 years, respectively.

Esophagogastrectomy and the variant left hepatic artery.

A variant left hepatic artery occurs at a rate of approximately 10%. In standard esophagogastrectomy and some proximal gastric operations this variant artery is sacrificed, which has led to reported fatalities secondary to hepatic necrosis. We report our method of esophagogastrectomy in the presence of an aberrant left hepatic artery.

Patient-controlled lumbar epidural fentanyl compared with patient-controlled intravenous fentanyl for post-thoracotomy pain.

Thirty-four patients undergoing thoracotomy were entered into a randomized, double-blind, placebo-controlled study to compare the effects of patient-controlled, lumbar epidural (PCA-E) fentanyl with patient-controlled intravenous (PCA-i.v.) fentanyl with respect to drug requirements, analgesic efficacy and respiratory function. Prior to chest closure patients received fentanyl 2 micrograms.kg-1 by the epidural or i.v. route. In the recovery room further doses of epidural or i.v. fentanyl, 50 micrograms, were administered by the patients who controlled two PCA pumps. Background fentanyl infusion rates were increased by 10 micrograms.hr-1 each time the patient administered a drug bolus and were decreased by 10 micrograms.hr-1 whenever visual analogue scale (VAS) pain scores were less than 2 on a maximum 10 scale. Twenty-nine patients completed the study. Patients in the PCA-E group (n = 14) required less total fentanyl than those in the PCA-i.v. (n = 15) group (1857 +/- 693 micrograms vs 2573 +/- 890 micrograms respectively, P less than 0.05). Fentanyl infusion rates were lower in the PCA-E group at most measurement times. There were no differences between groups in respiratory rates, PaCO2, VAS pain scores or changes in pulmonary function as measured by FVC and FEV1. It is concluded that satisfactory patient-controlled analgesia can be achieved with both epidural and i.v. fentanyl after thoracotomy but that fentanyl requirements are less when given via the epidural route. This supports a direct spinal cord site of action for lumbar epidural fentanyl.

Chest-wall tumours.

Between August 1984 and October 1988, 7 women and 16 men underwent chest-wall resection. The 23 patients ranged in age from 17 to 79 years. Resection was done for benign lesions in 9 patients, for recurrent chest-wall sarcoma in 4 and for carcinoma involving the chest wall in 10. The number of ribs resected ranged from none to six. Prosthetic material was required for reconstruction in eight patients. There were no operative deaths and no flail segments developed postoperatively. Three patients have since died of metastatic disease, one has died of unrelated causes but with no residual disease and the remainder were alive and well at follow-up intervals ranging from 11 to 60 months. Aggressive resection, including a wide margin of healthy tissue, provides the best chance for recurrence-free survival for patients with many types of chest-wall tumour. Resection can be performed with low morbidity and satisfactory cosmetic results.

Pulmonary capillary blood volume in emphysema.

We determined single breath diffusing capacity (DLCO) and pulmonary capillary blood volume (Vc) in a total of 110 patients, who were being evaluated for resectional lung surgery for a localized tumor or lesion. Pathologic assessment of emphysema was obtained in 55 cases who had resection of a lung or an upper lobe, based on a standard reference panel for emphysema grading. In 86 cases, the extent of emphysema was quantitated by computed tomography (CT) of the chest. There was a significant negative correlation between Vc and emphysema assessed by either pathology or CT (r = about -0.5, p less than 0.001) similar to the correlation between DLCO and the extent of emphysema. Results of Vc were significantly lower in cases with moderate emphysema (pathologic grade greater than or equal to 30) than those with no emphysema (grade less than or equal to 5) (p less than 0.001) or mild emphysema (grade 10 to 25) (p less than 0.05), and they were significantly lower (p less than 0.05) in the group with mild emphysema compared with the group with no emphysema on pathologic assessment similar to DLCO results. Although Vc was reduced in emphysema, determination of Vc did not result in improved discrimination in separating cases with emphysema from those without emphysema when compared with DLCO.

Effect of routine fibrin glue use on the duration of air leaks after lobectomy.

The effectiveness of fibrin glue as a sealant to reduce postoperative air leaks after pulmonary lobectomy was evaluated in 28 consecutive patients between November 1988 and May 1989. A fibrin glue spray was used in 14 patients, and 14 patients served as controls. Assignment of either group was made before thoracotomy. Nine male and 5 female patients with a mean age of 63.8 years were in the fibrin glue experimental group, and 8 male and 6 female patients with a mean age of 59 years, in the control group. An equal number of complete and incomplete fissures were in each group. All fissures were handled in the same way (stapled). Two milliliters of fibrin glue was applied through a double-syringe delivery system and sprayed on the staple line and any cut surface of the inflated lung just before thoracotomy closure. The fibrin glue-treated group had a mean air leak duration of 2.3 +/- 3.7 days, chest tube drains for 6 +/- 4.1 days, and a postoperative hospitalization of 9.8 +/- 3.1 days. The control group had a mean air leak duration of 3.3 +/- 3.3 days (p = 0.94), chest tube drains for 5.9 +/- 3.9 days (p = 0.95), and a postoperative hospitalization of 11.5 +/- 3.9 days (p = 0.21). We conclude that the routine use of a fixed quantity of fibrin glue is not effective in reducing the duration of air leaks, chest tube drainage, or hospitalization after uncomplicated pulmonary lobectomy.

Comparison of single breath carbon monoxide diffusing capacity and pressure-volume curves in detecting emphysema.

To evaluate the sensitivity of diffusing capacity (DLCO) and pressure-volume (P-V) curves in the detection of emphysema, these tests were compared with pathologic assessment of emphysema in patients undergoing lung resection for a localized tumor, and with the overall extent of emphysema as assessed by computed tomography (CT). The resected lung specimens were fixed in the inflated state and cut at 1-cm intervals in the horizontal plane. The pathologic extent of emphysema was quantitated by comparison with a standard reference panel of emphysema grading. The overall extent of emphysema on CT was assessed by a visual scoring system in a total of 55 patients, 19 undergoing lung resection and 36 not undergoing lung resection. Analysis of 37 patients by pathology scores revealed 18 with no or trivial emphysema (emphysema grades less than or equal to 5; mean grade, 2.2 +/- SD 2.6) and 19 with emphysema (grades greater than or equal to 10; mean grade, 33.2 +/- SD 24.2). Diffusing capacity, the ratio of DLCO to alveolar volume (DLCO/VA), maximal lung elastic recoil (PLmax), and lung elastic recoil at 90% of total lung capacity (PL90) were significantly different between the two groups, whereas K (the exponential constant describing the shape of the P-V curve) was not. The pathology grade of emphysema showed a significant correlation with (DLCO) (r = -0.53) and DLCO/VA (r = -0.55), which was greater than the correlation with PLmax (r = -0.42) and PL90 (r = -0.43).(ABSTRACT TRUNCATED AT 250 WORDS)

Primary anterior mediastinal tumours: "an investigational algorithm".

A review of 33 months' experience with primary anterior mediastinal masses in 31 patients disclosed that in 9 (29%) the tumour was benign. Nineteen (86%) of the 22 malignant tumours and only 2 of the 9 benign tumours were symptomatic. Diagnosis was established by histopathologic examination of a biopsy specimen or resected tissue and serum radioimmunoassay for alpha-fetoprotein or human chorionic gonadotropin, beta-subunit. The authors present an investigational algorithm, using modern procedures, to facilitate the diagnosis of this relatively uncommon and challenging condition.