A prospective analysis of 1400 pulmonary artery catheterizations in patients undergoing cardiac surgery

During 1983 and 1984, 1305 patients underwent 1,400 pulmonary artery (PA) catheterizations. Successful placement was achieved in 1397 (99.6%) of 1,403 attempts. The catheters were inserted via the right internal jugular vein on 1364 occasions. The median duration of monitoring was 28 h with a range from 3 to 220 h. Central venous puncture complications included carotid artery puncture in 67 instances (4.8%) and pneumothorax in one patient. Insertion of the catheters was associated with supraventricular arrhythmias on 11 occasions, ventricular arrhythmias on 930 (66.4%), right bundle branch block on two and a total heart block on one occasion. Eighteen (2.3%) of the 794 cultured catheter tips were positive. An in situ time of more than 72 h was associated with a significantly higher percentage (7.2%) of positive tip cultures compared with an in situ time of less than 72 h (P less than 0.01). Repeated PA catheterization was not associated with significantly more complications than the initial catheterization. The results show that monitoring with a PA catheter in cardiac surgical patients is associated with a low incidence of morbidity.     

Positive tip cultures and related risk factors associated with intravascular catheterization in pediatric cardiac patients

The incidence and risk factors of positive catheter tip cultures were studied prospectively in 392 consecutive children undergoing cardiac surgery under cover of cephalothin prophylaxis. A total of 1649 catheter tips were cultured and 58 (3.5%) yielded positive cultures. Specifically, the incidence of positive catheter tip cultures for iv, central venous, arterial and pulmonary arterial (PA) catheters was 0.9%, 5.9%, 3.9% and 10.6%, respectively, whereas one of the six surgically placed venous and arterial catheters had a positive tip culture and none of the 279 transthoracic catheters. Staphylococcus epidermidis was isolated from 79% of the positive tip cultures. Ten percent of the children had one or more positive tip cultures but none developed catheter-related septicemia or endocarditis. Stepwise logistic regression analysis revealed that longer in situ time (p less than .001), younger age (p less than .001), and inotropic support (p = .003) were significant independent predictors of risk for children developing positive catheter tip cultures. The safe in situ period for arterial, central venous, and PA catheters is 3 days in infants under 1 yr and 4 and 6 days for arterial and central venous catheters, respectively, in older children, if 0.95 cumulative probability of remaining free of a positive tip culture is accepted. The data generally support the bacteriologic safety of invasive hemodynamic monitoring in infants and children undergoing cardiac surgery.     

Results of the tension-free vaginal tape procedure for stress incontinence: Patient''s perspective

BACKGROUND: To evaluate the results of the tension-free vaginal tape procedure (TVT) from a patient's perspective. METHODS: Between May 1999 and January 2002, 90 patients underwent a TVT for genuine stress incontinence (GSI) and mixed incontinence. Prior to the procedure, GSI was confirmed by clinical examination and urodynamic studies. Results were then audited from patient notes and the same patients were sent questionnaires to examine results from a patient perspective. RESULTS: Overall response rate to the questionnaire was 70 (77%). The mean age of the patients was 50.4 years (range 31-83 years). Sixty-one patients had spinal anesthesia, seven had general anesthesia and two had local anesthesia. Mean hospital stay was 3.36 days (range 2-14 days) and mean period from the operation to the time of the survey and audit was 16.34 months (range 3-28; SD 6.92). Thirty-nine (56%) of the 70 patients who answered said that the operation had cured their incontinence, 16 (23%) had an improvement in their symptoms, 7 (10%) had worsening of their symptoms and 8 (11%) felt that the operation did not make any difference. The overall success rate according to the patients' perspective was 79%, whereas our audit showed an overall success rate of 86% (77% and 82%, respectively, when we compared only the 66 patients who had both notes and replies available for analysis). CONCLUSION: Although a patient's perception regarding the success of TVT tends to differ from that of a clinician, it was not found to be statistically significant (P = 0.22, McNemar test). The TVT is a very successful operation, but realistic cure rates should be offered to patients.     

Hodgkin disease: CT of the thymus

The computed tomography (CT) scans in two groups of patients with Hodgkin disease were reviewed to determine the frequency of thymic enlargement. In 50 CT scans from 50 patients with evidence of thoracic disease on CT scans who were examined for primary staging, the thymus was enlarged in 15 of 50 (30%). Fifty CT scans were obtained from 44 patients at the time of 50 separate episodes of known or suspected relapse. Relapse occurred in the mediastinum in 12 episodes, lung parenchyma in five, and both sites in one. Thymic enlargement thought to be due to involvement by disease was present in seven of 18 (38%). Mediastinal disease was associated with thymic enlargement in all but one patient in whom a thymic cyst developed after radiation therapy. Differentiation of thymic enlargement from enlarged superior mediastinal lymph nodes was easily made in all but two patients. Thymic enlargement in the absence of lymph node enlargement may indicate a different disease, since isolated Hodgkin disease of the thymus is uncommon. Primary thymic tumor should be considered initially, whereas after treatment, rebound hyperplasia of the thymus may be the cause of enlargement.     

Solid and papillary epithelial neoplasms of the pancreas: CT findings

Five female patients and one male patient with solid and papillary epithelial neoplasms of the pancreas were examined with computed tomography (CT). The mean age of the patients was 27 years (range, 13-46 years). All cases showed well-encapsulated, round or lobulated masses consisting of both cystic and solid areas. Cystic portions showed CT numbers that suggested hemorrhagic necrosis. There were no internal septations within the masses. In three tumors located in the head of the pancreas, dilatation of the biliary tree was absent or minimal, although the masses were large. Two tumors contained calcifications. One tumor demonstrated metastatic deposits in liver and lymph nodes. Metastatic masses appeared similar to the primary pancreatic mass. Solid and papillary neoplasm of the pancreas should be the primary diagnostic consideration when characteristic CT findings are detected in a young female patient.     

The Maillard reaction in demineralized dentin in vitro

The Maillard reaction between carbohydrate and protein has been proposed as a cause of the browning of carious lesions. The aim of the present investigation was to determine the occurrence of this reaction in bovine dentin collagen in vitro and to establish the effect of the reaction on the proteolytic degradation of bovine dentin collagen in vitro. Slices of demineralized bovine dentin were incubated with 0.2 M glucose or buffer for 10 weeks at 37°C. The formation of initial (furosine) and advanced (pentosidine) products of the Maillard reaction in dentin exposed to glucose was confirmed by HPLC. After reduction with NaBH₄ to prevent intermediate Maillard products from further reaction, slices were either degraded with collagenase for fluorescence measurement or incubated with trypsin or pepsin to assess enzymatic degradation. Fluorescence characteristic for the Maillard reaction increased in glucose-exposed slices. Degradation of collagen by pepsin, but not by trypsin, was greatly depressed following glucose pretreatment. This may indicate an altered sensitivity to proteolytic degradation; the Maillard reaction thus has a potential role in caries arrestment.     

Fusion of respiration-correlated PET and CT scans: correlated lung tumour motion in anatomical and functional scans

Lower lobe lung tumours in particular can move up to 2 cm in the cranio-caudal direction during the respiration cycle. This breathing motion causes image artefacts in conventional free-breathing computed tomography (CT) and positron emission tomography (PET) scanning, rendering delineation of structures for radiotherapy inaccurate. The purpose of this study was to develop a method for four-dimensional (4D) respiration-correlated (RC) acquisition of both CT and PET scans and to develop a framework to fuse these modalities. The breathing signal was acquired using a thermometer in the breathing airflow of the patient. Using this breathing signal, the acquired CT and PET data were grouped to the corresponding respiratory phases, thereby obtaining 4D CT and PET scans. Tumour motion curves were assessed in both image modalities. From these tumour motion curves, the deviation with respect to the mean tumour position was calculated for each phase. The absolute position of the centre of the tumour, relative to the bony anatomy, in the RCCT and gated PET scans was determined. This 4D acquisition and 4D fusion methodology was performed for five patients with lower lobe tumours. The peak-to-peak amplitude range in this sample group was 1-2 cm. The 3D tumour motion curve differed less than 1 mm between PET and CT for all phases. The mean difference in amplitude was less than 1 mm. The position of the centre of the tumour (relative to the bony anatomy) in the RCCT and gated PET scan was similar (difference <1 mm) when no atelectasis was present. Based on these results, we conclude that the method described in this study allows for accurate quantification of tumour motion in CT and PET scans and yields accurate respiration-correlated 4D anatomical and functional information on the tumour region.     

Variable selection under multiple imputation using the bootstrap in a prognostic study

Background  

Missing data is a challenging problem in many prognostic studies. Multiple imputation (MI) accounts for imputation uncertainty that allows for adequate statistical testing. We developed and tested a methodology combining MI with bootstrapping techniques for studying prognostic variable selection.