Analysis of early failure of tunneled hemodialysis catheters.

OBJECTIVE: Tunneled hemodialysis catheters are often placed by the interventional radiology service using sonographic guidance and fluoroscopy for safe and optimal placement. The aim of this study was to determine the causes of early failure (

Image-guided central venous catheter placement for apheresis in allogeneic stem cell donors.

Peripheral blood stem cell harvest by apheresis is an increasingly important procedure utilized in the treatment of many malignancies. Whether autologous or allogeneic, it is frequently performed via peripheral access because of concern over major complications associated with central venous catheter placement. This study was to determine the safety and success, complications and premature failure rates for radiolocally placed ultrasound-guided non-tunneled central venous catheters placed for apheresis in a donor (allogeneic) population. One hundred central venous catheters were placed in ninety-one individuals for allogeneic stem cell harvest. Procedural success and complications relating to placement were noted in all. In 97 cases the number of needle passes required for venous cannulation and whether this was achieved with a single wall puncture was noted. Duration of catheterization and reason for removal were recorded in all cases. All catheters were placed by a right transjugular route. Venous cannulation and functioning line placement was achieved in every case; 92/97 (95%) required only a single needle pass and 84/97 (87%) only a single wall puncture. There were no placement related complications; 94 catheters were removed the same day with the remainder removed within 48 hr. All completed apheresis. Our study demonstrates the safe use of central venous catheters for apheresis in normal donors if ultrasound guidance is used for the puncture and the duration of catheterization is short.

Value of frontal caval measurement in the placement of inferior vena cava filters.

OBJECTIVE: Inferior vena cavae (IVC) can be of unusual geometry, often having odd shapes and being oriented (in long axes) away from the horizontal plane. However, after insertion of a filter, most IVC adopt a circular cross-section. The objective of this study was to determine if the IVC diameter estimated by frontal measurement (cavogram equivalent) reflects the true circular diameter of the infrarenal vena cava. Diameter estimation is clinically important in the correct selection of a filter, because mega cavae (diameter 28 mm or greater) require a particular filter. METHODS: The infrarenal IVC was measured on computed tomographic (CT) scans in 136 patients. The frontal diameter was recorded as that which would be obtained by a cavogram. Corrected circular diameter was obtained by mapping the circumference of each cross-section on CT to a straight line and calculating diameter from circumference. RESULTS: The average frontal caval diameter was 20.5 (standard deviation 3.7) mm, whereas the average corrected circular diameter was 23.0 (standard deviation 3.4) mm. By frontal measurements, 6 IVC diameters were 28.0 mm or greater. Similarly, by corrected circular diameter, 6 IVC diameters were 28.0 mm or greater. However, of the 6 mega cavae extrapolated to cavograms, only 3 corresponded to mega cavae when corrected for true circular diameter. Yet, of the 6 mega cavae identified by corrected circular diameter measurement, 3 were not identified by frontal diameter assessment. Of the 6 patients with true mega cavae, 2 were being evaluated for right lower quadrant pain, 2 for lymphoma, 1 for a pelvic mass, and 1 for staging of a head and neck cancer. CONCLUSIONS: Cavograms can over- or underestimate the true diameter of an IVC, and may thus lead to incorrect filter choice. It is recommended that a sonogram or CT scan be obtained to visualize the IVC in cases of suspected mega cava, and that true circular diameters be used for selection and placement of IVC filters.

Should anticoagulant therapy be stopped or reversed before venous intervention?

PURPOSE: To determine the safety of venous intervention and the incidence of complications in patients undergoing venous interventional radiological procedures while receiving anticoagulant therapy. METHOD: Data were collected prospectively for a 1-year period. One hundred patients receiving anticoagulant therapy underwent interventional radiological procedures requiring venous cannulation. Of these, 87 had documented prolonged bleeding times. There were 50 inferior vena cavograms obtained and filters placed (29 transfemoral, 21 transjugular), and 50 transfemoral pulmonary angiogram obtained, all in patients with thrombo-embolic disease who were receiving anticoagulant therapy. In most cases venous access was achieved with real-time sonographic guidance. RESULTS: Venous access was gained in all patients in all groups. There were 41/50 filter placements and 46/50 pulmonary angiograms performed in the patients with prolonged clotting times in or above the therapeutic range. There were no cases of arterial puncture and no cases of venous bleeding either during or after the procedures. No other complications were recorded. CONCLUSION: Venous intervention in patients receiving therapeutic anticoagulation is safe, with no complications reported in our series. There is no need to discontinue anticoagulant therapy in patients with life-threatening thrombo-embolic disease. Real-time sonographic guidance greatly facilitates venous cannulation and avoids inadvertent arterial puncture.

A simplified method of gastropexy for transgastric enterostomy.

Radiological placement of gastrostomy tubes was first described in 1983. Percutaneous gastropexy to facilitate gastrostomy placement was reported in 1986. Debate has continued to this day regarding the necessity of gastric fixation. We describe our technique of a simplified gastropexy to facilitate transgastric enterostomy and advocate its more widespread use.

Radiologic placement of tunneled central catheters: rates of success and of immediate complications in a large series.

OBJECTIVE: The objective was to examine the success and immediate complication rates in a large series of radiologically placed tunneled central venous catheters. SUBJECTS AND METHODS: We prospectively recorded the success and immediate complication rates in 880 consecutive radiologically placed tunneled central venous catheters. We also recorded the indication for placement, the success of placement, the number of passes required, and whether a double- or single-wall puncture occurred. RESULTS: Hemodialysis was the most common indication for long-term venous access. Venous access was successful in all patients, and catheter placement was successful in 99.4% of patients, with only five failed placements. All patients in whom placement was initially unsuccessful underwent successful placement the same day. All catheters were placed using real-time sonographic guidance. Most were placed in an internal jugular vein, with 87.4% requiring only a single needle pass. The immediate complication rate was only 4.0%, and no major complications occurred. CONCLUSION: To our knowledge, this series is the largest for which the immediate complication and success rates for radiologically placed central venous catheters have been reported. Our results suggest that radiologic placement of tunneled central venous catheters is a safe and effective alternative to surgery.

Apheresis: another indication for radiologically placed central venous catheters.

OBJECTIVE: Apheresis is an important technique, used increasingly for a variety of conditions. It is sometimes performed via peripheral access because of concern over major complications associated with central venous catheter (CVC) placement. This study was to determine the safety and success of radiologic placement of CVCs for apheresis. METHODS: Data were collected prospectively for 278 CVCs placed under real-time sonographic or fluoroscopic guidance in the radiology department. Complications were noted in all cases; the number of passes required for venipuncture and whether this was achieved with a single wall puncture were noted in 265 cases; duration of catheterization and reason for removal of the catheter were recorded in all cases. The study group included 83 donors providing peripheral blood stem cells for allogeneic transplant. RESULTS: CVCs were successfully placed in all patients, 269 in the internal jugular and 9 in the femoral vein. In 87% of cases, only a single pass was required, and in 80% of cases venipuncture was achieved with a single anterior wall puncture. There was inadvertent but clinically insignificant arterial puncture in 6 cases (2%). In no case did this prevent CVC placement. Most catheters (211/274, 77%) were removed the same day. Only 3 catheters were removed prematurely (1%), 1 because of infection and 2 because of clotting. There was 1 case of venous bleeding. CONCLUSION: CVCs are safe for apheresis if real-time sonographic guidance is used for the puncture, guide wire and catheter placement are confirmed fluoroscopically, and the duration of catheterization is short.

Predicting infection in localized intraabdominal fluid collections: value of pH and pO2 measurements.

PURPOSE: To evaluate the use of pH, pO2, and the subjective opinion of the radiologist compared with bacterial culture in accurate diagnoses of bacterial infection in intraabdominal fluid collections. MATERIALS AND METHODS: Prospectively, 79 patients who were suspected of having an intraabdominal fluid collection underwent diagnostic fluid aspiration. The aspirate was cultured and measured for pH and pO2. A pH < or = 7.1 and a PO2 < or = 49 mm Hg were threshold values used to separate infected from sterile fluid collections. RESULTS: pH alone had a 92% sensitivity and 79% specificity, whereas PO2 alone had a 51% sensitivity and 79% specificity. pH or pO2 combined yielded a 92% sensitivity and 60% specificity. The radiologist's opinion produced a 83% sensitivity and 92% specificity. pH and the radiologist's opinion combined produced a 78% sensitivity and 96% specificity. pH or the radiologist's opinion combined had a 95% sensitivity and a 63% specificity. CONCLUSION: pH is the most sensitive indicator of infection and the radiologist's opinion is the most specific. We recommend proceeding to drainage if the radiologist believes the collection to be infected and performing pH analysis if not. If the pH < or = 7.04, proceed to drainage. If neither of the above criteria are met, drainage could be delayed, pending the results of culture.

Image-guided central venous catheters for apheresis.

Apheresis is an increasingly important procedure in the treatment of a variety of conditions, sometimes performed via peripheral access because of concern over major complications associated with central venous catheter (CVC) placement. This study sought to determine the safety and success for ultrasound and fluoroscopically guided, non-tunneled dual lumen CVCs placed for apheresis. Prospective data collection was made of 200 attempted CVC placements in the radiology department utilizing real time sonographic guidance. The complications relating to placement were noted in all and the number of passes required for venepuncture and whether a single wall puncture was achieved was recorded in 185 cases. Duration of catheterization and reason for line removal were recorded in all. Our study group included 71 donors providing peripheral blood stem cells for allogeneic transplant. CVCs were successfully placed in all patients, 191 lines in the internal jugular and seven in the femoral vein. 86.5% required only a single pass and 80.5% with only anterior wall puncture. Inadvertent but clinically insignificant arterial puncture occurred in six (3%) cases. In no case did this prevent line placement. There were no other procedure-related complications. 173 (87.4%) catheters were removed the same day. No catheters were removed prematurely. There was one case of prolonged venous bleeding. Our study demonstrates the safety of central venous catheters for apheresis provided that duration of catheterization is short and real-time sonographic guidance is used for the puncture, and guide wire and catheter placement are confirmed fluoroscopically.

Craniocervical bone pneumatisation.

We report a case of extensive craniocervical bone pneumatisation presenting after minor trauma. The patient had neurological signs and initial radiographs showed multiple lucencies in the skull base and the atlas vertebra. CT established the true nature of this rare condition.

Intravenous contrast media reactions: how do radiologists react?

Following the publication of the Royal College of Radiologists guidelines for the management of reactions to intravenous contrast media we assessed radiologists' understanding of intravenous contrast media reactions and their management of specific adverse reactions. A confidential questionnaire was sent to all radiologists in the Northern Region. Responses were received from 61/101 (60%). Knowledge of minor contrast media reactions was generally good but the understanding of treatment of severe reactions was poor. Knowledge of optimal management was inversely related to radiological seniority. This study suggests a poor understanding of severe contrast media reaction management amongst radiologists. Simplified treatment guidelines based on the Royal College document and aimed at severe reactions are suggested.

The effects of oral administration of salts of aspartic acid on the metabolic response to prolonged exhausting exercise in man.

The effects of the oral administration of salts of aspartic acid on endurance capacity and metabolic responses to prolonged bicycle exercise have been investigated. Previous reports in man and in animals have suggested that this treatment can increase the capacity to perform muscular work by virtue of its effect on circulating ammonia levels. Eight healthy young male subjects exercised to exhaustion on a bicycle ergometer at a work load requiring approximately 75% of maximum oxygen uptake. This work test was performed after placebo administration or after ingestion of 6 g of potassium-magnesium aspartate over a 24-h period, using a double-blind protocol. Exhaustion was reached after 82.7 +/- 23.5 min (mean +/- SD) following aspartate treatment and after 85.4 +/- 26.5 min following the placebo. No differences in the blood glucose, lactate, or ammonia concentrations or in the plasma free fatty acid concentration between the two treatments were observed. The respiratory exchange ratio was the same on both occasions. These results show no beneficial effect of oral aspartate administration on work capacity in man and also suggest that the metabolic processes that occur during exercise are not influenced by this treatment.