Stephens Lc

Are Clinical Signs Accurate Indicators of the Cause of Central Venous Catheter Occlusion

BACKGROUND Two hundred dysfunctional central venous catheters used for total parenteral nutrition and administration of cancer chemotherapy were radiographically examined in order to objectively identify thrombotic occlusions as the cause of catheter dysfunction. METHODS Outcomes of radiographic dye injections were compared with factors such as the inability to aspirate blood or to infuse fluids, catheter type, and duration of catheter placement. RESULTS Catheter type and duration of placement were not significant factors for predicting the type of dysfunction. Failure to withdraw blood was associated with 96% of the thrombosed catheters; this was also associated with 65% of the catheters with nonthrombotic dysfunctions. Once the cause of catheter occlusion was correctly identified, 90% of the catheters were restored to normal function. CONCLUSIONS Inability to withdraw blood from a catheter does not necessarily mean it is occluded by thrombus. Mechanical complications account for a significant portion of dysfunctional catheters.

Normal saline versus heparin flush for maintaining central venous catheter patency during apheresis collection of peripheral blood stem cells (PBSC)

Thrombotic occlusion is frequently a complication of central venous catheters (CVCs). The original designers and producers of CVCs recommended heparin flush regimens to prevent thrombosis and maintain patency. This has become standard practice although no studies have demonstrated a relationship between heparin flushing and reduction of catheter thrombosis. Many consider the routine use of heparin flushing innocuous. However, serious complications including drug interactions and heparin induced thrombocytopenia and thrombosis syndrome (HITS) have been reported in association with heparin flushing. Numerous studies comparing heparin to saline flushing in peripheral devices suggest equal rates of thrombotic occlusions. The purpose of this study was to examine the incidence of thrombotic occlusions in CVCs using heparin compared to saline flushing. The study involved 78 cancer patients undergoing apheresis collection for peripheral blood stem cells; 29 received saline flushes and 49 received heparin (100 U/ml of saline) flushes. Study endpoints included slow apheresis flow rate (< 50 ml/min), urokinase use for thrombolysis, and radiographic evidence of catheter thrombosis. No significant differences were found for any endpoint between the two groups. These findings suggest saline may be as effective as heparin for maintaining patency of CVCs.

Increased platelet transfusion requirement is associated with multiple organ dysfunctions in patients undergoing hematopoietic stem cell transplantation

Organ dysfunction following hematopoietic stem cell transplantation (HSCT) may be a manifestation of a systemic inflammatory response. We speculate that part of the platelet transfusion requirement in HSCT patients results from this systemic inflammatory response, and increased transfusion requirement would be associated with, or precede, organ dysfunction. We studied 199 adults undergoing autologous (n = 173) or allogeneic (n = 26) HSCT. Patients with CNS (P = 0.008) or pulmonary (P = 0.002) dysfunction, or with VOD (P = 0.05) received a higher mean number of platelet transfusions per week than patients who did not have these dysfunctions. Furthermore, a higher number of platelet transfusions during any 1 week period was significantly associated with development of pulmonary (P = 0.0002) or renal (P < 0.0001) dysfunction in the following week. this predictive value was strongest early in the hsct course, but remained significant over all 4 weeks. in multivariate analysis the number of platelet transfusions during the previous week was independently predictive for development of pulmonary dysfunction in week 2 (P = 0.01) and week 3 (P = 0.055). We believe that occurrence of increased platelet transfusion requirement prior to onset of dysfunction is consistent with the concept that an antecedent inflammatory response results in both platelet consumption and various organ dysfunctions. Increased platelet transfusion requirement may act as an early marker of subsequent organ dysfunction. Additionally, there may be a direct role of platelets in the development and progression of organ dysfunction in HSCT patients.

Double-lumen inferior vena cava catheters for peripheral stem cell apheresis and transplantations.

No previously published studies have described double-lumen hemodialysis/apheresis catheters for use with continuous-flow apheresis collection of peripheral stem cell (PSC). We prospectively evaluated experiences with these catheters during both PSC collection and transplantation. Because of previously-described successful experiences with single-lumen apheresis catheters placed in the inferior vena cava, all catheters evaluated in this study were placed in this anatomic location. Our experience demonstrated high rates of thrombotic occlusion (65%) and catheter-related infections (15%). This method of access should not be considered optimal in its present state of use. Further investigation into preferred catheter design, anatomic location, and thrombosis prophylaxis during continuous-flow apheresis is warranted.

Factors predicting morbidity following hematopoietic stem cell transplantation.

Circulating anticoagulants protein C (PC) and antithrombin III (AT) are markers of, and possibly involved in the pathogenesis of, significant organ dysfunction, in patients undergoing autologous peripheral blood stem cell (PSBC) or autologous bone marrow (BM) transplantation. The effect of the stem cell source, the use of hematopoietic growth factors (GFs), and the specific preparative regimen on the incidence of organ system dysfunction or on post-transplant levels of circulating anticoagulants has not been well studied. We analyzed 205 patients in an attempt to correlate organ dysfunction and AT and PC deficiencies with these transplant-specific factors (78 BMT with GM-CSF after transplant, 95 PBSCT without GM-CSF after transplant, and 32 PBSCT with GM-CSF after transplant). Patients transplanted with PBSC had a lower incidence of pulmonary dysfunction (20 vs 40%, P = 0.006) and liver dysfunction (4  vs 13%, P = 0.05) than patients receiving BM. The use of GF after transplant did not influence the development of subsequent organ dysfunction. In multivariate analysis, the stem cell source was again predictive of pulmonary dysfunction. In contrast, although patients transplanted with PBSC also had a lower incidence of PC deficiency (50 vs 81%, P < 0.01) and AT deficiency (20 vs 54%, P < 0.01) as compared with patients receiving BM, use of GM-CSF after transplant was a more significant risk factor for the development of anticoagulant deficiency (PBSC with GF vs PBSC without GF: PC deficiency 50 vs 78%, P = 0.007; AT deficiency 20 vs 47%, P = 0.005). In the multivariate analysis GM-CSF use was the only significant risk factor for development of anticoagulant deficiency. Since the clinical significance of anticoagulant deficiency has been well shown, further studies examining these effects of hematopoietic GFs appear warranted.