Brent Burbridge

Preliminary Clinical Experience with the Gunther Temporary Inferior Vena Cava Filter

PURPOSE The authors describe their preliminary clinical experience with the Gunther temporary inferior vena cava (IVC) filter. PATIENTS AND METHODS Seven women and 10 men, mean age 52 years (range, 19-85 years), were treated with the temporary IVC filter. Indications for filter placement were pulmonary embolism (PE) in four patients and iliofemoral deep venous thrombosis in six. In these patients anticoagulation was contraindicated because of planned major surgery. Filters were placed in four patients following massive PE and in three for prophylaxis following cranial trauma. Four patients had underlying malignant disease. Filters were introduced through the right common femoral vein in 14 patients, the left common femoral vein in two, and the left internal jugular vein in one. RESULTS No patient developed recurrent PE with the filter in place. All filters were removed without complication 3-14 days (mean, 7 days) after placement. Two of the patients with underlying malignant disease required placement of a permanent filter. Two patients developed IVC thrombosis with the filter in place, and both developed recurrent PE after filter removal. Two patients developed insertion vein thrombosis. One patient developed a bleeding disorder that caused a massive hematoma at the insertion vein site, which may have contributed to her death. CONCLUSION The Gunther temporary filter can be used in selected patients; however, patients with underlying malignant disease may be more appropriately treated with a permanent filter. The temporary filter does not appear to reduce the rate of insertion vein and IVC thrombosis.

LGM (Vena Tech) Vena Caval Filter: Experience at a Single Institution

PURPOSE The authors describe their experience with LG-Medical (LGM [Vena Tech]) filter placement and follow-up. PATIENTS AND METHODS LGM vena cava filters were placed in 63 patients. Follow-up was obtained by means of duplex sonography of the introduction vein and inferior vena cava (IVC) and abdominal radiography in 50 patients, and by means of autopsy in an additional four patients. In eight, only clinical follow-up was obtained and one patient was lost to follow-up. RESULTS Major complications of placement occurred in three patients, all when the right internal jugular vein was used for introduction: In one patient a filter was inadvertently placed in the right renal vein and in two the filter failed to open fully. No serious complications of placement occurred when either the right or left common femoral veins were used. Pulmonary embolism (PE) recurred in four patients (6%) and was fatal in one. Septicemia from an infected filter was the probable cause of death in another patient. Introduction vein thrombosis occurred in five patients (8%) and was symptomatic in two (3%). Occlusion of the IVC occurred in 15 patients (24% of the total patient group, but 28% of those with objective follow-up) and was symptomatic in 12 (19%). Two patients with IVC occlusion had recurrent PE. CONCLUSION These data suggest that the rate of IVC occlusion is higher than most previous reports have suggested and that IVC occlusion may be a potentially serious complication.

Respiratory function after cardiac surgery

STUDY OBJECTIVE Cardiac surgery is complicated by decreased postoperative respiratory muscle strength and spirometry with accompanying increased atelectasis. The specific respiratory symptoms attributable to these physiologic changes are unknown, and this study looked at the symptoms and underlying physiology. DESIGN Convenience sampling of observational cohort. SETTING Tertiary care university hospital. PATIENTS One hundred thirty-eight patients undergoing elective surgery were enrolled. INTERVENTIONS Changes from admission to 8-week postoperative values in atelectasis, pleural effusions, spirometry (forced vital capacity and forced expiratory volume in one second), and respiratory muscle strength (negative inspiratory pressure) were measured. These physiologic changes were compared with changes in respiratory symptoms of cough, wheeze, phlegm, and dyspnea on walking up a slight hill noted from admission to 8-week follow-up by stepward logistic regression. MEASUREMENTS AND RESULTS Spirometry and negative inspiratory pressure decreased and atelectasis increased from admission to discharge. These disturbances had only incompletely resolved at 8-week follow-up. Some patients reported fewer symptoms of cough (11%), phlegm (9%), wheeze (35%), and dyspnea (46%) at 8 weeks follow-up. Other patients reported increased symptoms of cough (15%), phlegm (10%), wheeze (6%), and dyspnea (4%) at 8 weeks follow-up. Residual atelectasis at 8 weeks was predictive of fewer symptoms of dyspnea (odds ratio [OR] 0.335, p = 0.199; 95% confidence interval [CI] 0.188, 0.597), increased symptoms of dyspnea (OR 855, p = 0.006; 95% CI 6.6, 11052), and increased symptoms of cough (OR 260, p = 0.023; 95% CI 2.13, 31829). Negative inspiratory pressure at 8 weeks was predictive of fewer symptoms of dyspnea (OR 1.05, p = 0.032; 95% CI 1.02, 1.09) and increased symptoms of wheeze (OR 0.7, p = 0.45; 95% CI 0.533, 0999). Forced vital capacity at 8 weeks was predictive of increased symptoms of wheeze (OR 0.005; p = 0.015; 95% CI 0.0060, 0.775). CONCLUSIONS Postoperative changes in respiratory muscle strength and spirometry can persist up to at least 8 weeks postoperatively. Many patients report a change in respiratory symptoms of cough, phlegm, dyspnea, or wheeze. The change in respiratory symptoms at 8 weeks is correlated with residual respiratory muscle weakness, decrease in spirometry, and residual atelectasis.

Depletion of activated neutrophils by a filter during cardiac valve surgery.

PurposeTo determine whether inclusion of a neutrophil-specific filter into the extracorporeal circuit during open heart valve surgery alters postoperative outcomes.MethodsConvenience sampling of 24 patients undergoing elective open heart valve surgery between July 1993 and June 1994. Patients were randomized to a neutrophil-specific filter (n= 11) or to a standard blood filter (n= 13) during cardiopulmonary bypass.ResultsNeutrophil-specific filter diminished (P < 0.02) the expression of CD 18, a neutrophil surface adhesion molecule, at 1 (84.5 ± 4.2 vs 94.8 ± 3.8%). 4 (80.0 ± 4.2 vs 95.1 ± 3.9%) and 24 hr (75.2 ± 4.2 vs 98.2 ±3.9%) post-operatively compared with standard filter. Total white blood cell count, neutrophil count, and proinflammatory cytokmes (IL-6, IL-8) were similar between groups at all times. Measured outcomes including: PaO2, cardiac index, ejection fraction, haemodynamic variables, use of motropes, spirometry (FEV FVC). and hospitalization duration were similar between groups.ConclusionsInclusion of the neutrophil filter during open heart valve surgery selectively depletes activated neutrophils. There were no other detectable differences between the two groups and the use of a neutrophilspecific filter in routine clinical practice for patients undergoing open heart valve surgery is not supported.RésuméObjectifDéterminer si l’ajout au circuit extracorporel d’un filtre spécifique aux neutrophiles pendant une chirurgie valvulaire modifiait les résultats de l’interventionMéthodesUn échantillonnage de 24 patients subissant une intervention valvulaire à coeur ouvert entre juillet 1993 et juin 1994. Les patients ont été répartis aléatoirement à un circuit extracorporel incluant un filtre spécifique aux neutrophiles (n= 11) ou un filtre standard (n= 13).RésultatsLe filtre spécifique aux neutrophiles a diminué l’expression de CD 18. une molécule adhésive de sur face, une heure (84.5 ± 4.2 vs 98.8 ± 3.8%), quatre heures (80 ± 4,2 vs 95.1 ± 3,9%) et 24 heures (75.2 ± 4,2 vs 98.2 ± 3.9%) après l’opération comparativement au filtre standard. Le décompte total des globules blancs, des neutrophiles et des cytokines pro-inflammatoires (IL-6. IL8) étaient à tous les moments identiques entre les groupes. Les mesures de résultats incluant la PaO2, l’index cardiaque, la fraction d’éjection, les données hémodynamiques, l’utilisation d’inotropes, la spirométne (VEMS, CVF) et la durée du séjour hospitalier étaient identiques entre les groupes.ConclusionL’ajout d’un filtre spécifique aux neutrophiles pendant la chirurgie à coeur ouvert épuise sélectivement les neutrophiles activés. Aucune autre différence n’est discernable entre les groupes. L’utilisation courante de filtres spécifiques aux neutrophiles en clinique chez des patients soumis à une chirurgie valvulaire à coeur ouvert n’est pas justifiée.

Temporary Inferior Vena Cava Filters: In Vitro Comparison with Permanent IVC Filters

PURPOSE An in vitro comparison of clot-trapping abilities of permanent and temporary inferior vena cava (IVC) filters. MATERIALS AND METHODS A flow model was used to simulate the IVC. Two permanent IVC filters, the titanium Greenfield and LG-Medical (LGM), were compared with two temporary filters, the Filcard International and Gunther. Clot sizes used were 2.5 x 2.5 mm, 2.5 x 5 mm, 5 x 5 mm, 5 x 10 mm, and 5 x 20 mm. Individual clots were presented to the filters with the simulated IVC in a horizontal or vertical orientation. Clot-trapping dynamics and pressure gradient changes during the injection of multiple, sequential clots were also examined. RESULTS As clot size diminished, all filters trapped fewer clots; however, the temporary filters trapped more small clots than the permanent filters. Very little difference was observed in clot-trapping abilities among the filters for clots of 5 x 10 mm or greater. In the horizontal orientation, the permanent filters trapped 38% of all clots delivered, while the temporary filters trapped 73%, chi 2 = 24.8 (P < .001). In the vertical orientation, the overall clot-trapping abilities of the filters improved, with the permanent filters trapping 73% of all clots delivered, while the temporary filters trapped 95%, chi 2 = 18 (P < .001). During trapping of multiple clots, the temporary filters allowed fewer clots to pass. CONCLUSION The temporary filters performed better than the permanent filters in both individual clot-trapping orientations. During multiple clot-trapping experiments, fewer clots were allowed to pass by the temporary filters. The temporary filters demonstrated the ability to capture clots both inside and outside the wire struts.

Pseudoaneurysm secondary to pancreatitis presenting as GI bleeding.

Pseudoaneurysm formation is a rare but potentially dev~astating complication of pancreatitis. It can be diag~nosed by using various imaging modalities including computer tomography, ultrasound, and angiography and should be entertained in any patient with a history of pancreatitis. We present the imaging findings in three patients with pseudoaneurysm formation secondary to pancreatitis who initially presented with gastrointestinal bleeding.

The Utilisation of Radiology for the Teaching of Anatomy in Canadian Medical Schools

Objective To determine the utilisation of diagnostic imaging (radiology) as a department and/or imaging medium in the teaching of anatomy at the Canadian undergraduate medical education level. Methods The study objectives were achieved through the use of a questionnaire and a literature review. The anatomy department head at each English-based Canadian Medical School was contacted, and the individual most responsible for anatomy teaching in the medical school curriculum was identified. This individual was subsequently asked to complete a questionnaire that evaluated the involvement of radiology for anatomy teaching in their curriculum. Results The use and integration of radiology is a common practice in the teaching of anatomy in Canadian undergraduate medicine. Although the methods and extent of its use varied among institutions, every English-based Canadian medical school, except one, was using diagnostic imaging material in their instruction of anatomy. Furthermore, half of the institutions had a radiologist as a faculty member of their anatomy department to help teach and to use imaging to its full potential. Discussion This audit of anatomy departments suggests that diagnostic imaging has an important role to play in anatomy teaching in Canadian English-speaking medical schools.

Retroperitoneal actinomycosis masquerading as inflammatory pseudotumor

Inflammatory pseudotumors present clinically as mass lesions and microscopically show a spectrum of nonspecific inflammatory and regenerative changes. When the mesentery or retroperitoneum are involved, differentiation from inflammatory fibrosarcoma poses a diagnostic problem. The authors report on a 7-year-old boy who presented with fever, anemia, weight loss, and a retroperitoneal mass. Needle biopsy results of the mass showed features consistent with inflammatory pseudotumor. Examination of the resected mass showed actinomycosis.

Catheter Fracture and Embolization Associated With Arm Implantation of the Cook Vital Port

Purpose To determine the frequency of arm port catheter fracture and embolization related to the Cook Vital Port Mini Titanium. Materials and Methods A retrospective audit of our Cerner Radiology Information System was performed between June 1, 2006, and June 30, 2011, to determine the number of Cook arm venous ports implanted and the frequency of foreign body retrievals related to catheter fracture for these arm ports. Results A total of 691 arm implantations of the Cook Vital Port during the 5-year time frame were analysed. Eleven of these patients (1.6%) required intravenous foreign body retrieval in the interventional radiology suite related to catheter fracture and embolization. Three of these fractured catheters were retrieved from the peripheral venous system upstream of the pulmonary circulation, whereas 8 embolized to the pulmonary arteries. All were successfully extracted with an intravenous snare by interventional radiology. Conclusion We discovered a 1.6% frequency of catheter fracture and embolization associated with arm implantation of the Cook Vital Port. All the catheters fractured at the vein entry site and did not detach from the port housing. The cause for catheter fracture and embolization is uncertain. Pulmonary embolization of the fractured catheters puts the patients at risk for possible further complications. No patients had ancillary complications related to catheter embolization or to catheter extraction procedures. Further investigation is required in an attempt to determine the circumstances that may result in catheter fracture and embolization related to this venous access device.

Percutaneous subclavian artery stent-graft placement following failed ultrasound guided subclavian venous access

BackgroundUltrasound guidance for central and peripheral venous access has been proven to improve success rates and reduce complications of venous cannulation. Appropriately trained and experienced operators add significantly to diminished patient morbidity related to venous access procedures. We discuss a patient who required an arterial stent-graft to prevent arterial hemorrhage following inadvertent cannulation of the proximal, ventral, right subclavian artery related to unsuccessful ultrasound guided access of the subclavian vein.Case presentationDuring pre-operative preparation for aortic valve replacement and aorto-coronary bypass surgery an anesthetist attempted ultrasound guided venous access. The ultrasound guided attempt to access the right jugular vein failed and the ultrasound guided attempt at accessing the subclavian vein resulted in inappropriate placement of an 8.5 F sheath in the arterial system. Following angiographic imaging and specialist consultations, an arterial stent-graft was deployed in the right subclavian artery rather than perform an extensive anterior chest wall resection and dissection to extract the arterial sheath. The patient tolerated the procedure, without complication, despite occlusion of the right internal mammary artery and the right vertebral artery. There were no neurologic sequelae. There was no evidence of hemorrhage after subclavian artery sheath extraction and stent-graft implantation.ConclusionThe attempted ultrasound guided puncture of the subclavian vein resulted in placement of an 8.5 F subclavian artery catheter. Entry of the catheter into the proximal subclavian artery beneath the medial clavicle, the medial first rib and the manubrium suggests that the operator, most likely, did not directly visualize the puncture needle enter the vessel with the ultrasound. The bones of the anterior chest impede the ultrasound beam and the vessels in this area would not be visible to ultrasound imaging. Appropriate training and supervised experience in ultrasound guided venous access coupled with quality ultrasound equipment would most likely have significantly diminished the likelihood of this complication. The potential for significant patient morbidity, and possible mortality, was prevented by implantation of an arterial stent-graft.