A case report of a new pulmonary embolism occurring in a patient receiving continuous infusion of recombinant activated protein C.

BACKGROUND: There are no guidelines governing the concomitant use of recombinant human activated protein C (rhAPC) and deep venous thrombosis/pulmonary embolism (DVT/PE) prophylaxis in critically ill patients. It is unknown if rhAPC provides any protection against DVT/PE in this population of patients. METHODS: Case report. RESULTS: This report describes the first case of a radiographically demonstrated pulmonary embolism occurring in a patient receiving continuous therapeutic infusion of rhAPC. CONCLUSION: The administration of rhAPC alone may not be sufficient DVT/PE prophylaxis in high risk patients. The risks associated with concomitant anticoagulation and rhAPC therapy are unknown. Further research is necessary to determine the safest and most effective regimen for DVT/PE prophylaxis in patients receiving rhAPC.

Performance of a dose-defining insulin infusion protocol among trauma service intensive care unit admissions.

BACKGROUND: Among critically ill patients, glycemic control reduces mortality and morbidities, but the use of intravenous insulin infusion is complicated by hypoglycemia. Having a standardized algorithm increases the likelihood of effective and safe utilization of intravenous insulin therapy. A tabular dose-defining protocol for intravenous insulin infusion is described, containing design elements intended to minimize risk for hypoglycemia while seeking control in a narrow target range, and performance is evaluated among critically ill trauma service patients. METHODS: The protocol assigns insulin infusion rate (IR) for ranges of blood glucose (BG). The columns are arranged in order of increasing maintenance rate (MR) for insulin infusion. Patient column assignment is determined according to rate of change of BG. During stable column assignment, the IR is a function of column MR and BG. Within-column, the protocol formula provides that (a) for BG between 70 mg/dL and target BG, the IR increases exponentially to the column MR; and (b) for BG above upper target BG range, the IR increases linearly as an adaptation of the rule of 1800, with slope determined by the column MR. Values for IR calculated by formula are rounded to correspond to BG ranges of the table. Performance was assessed in 27 sequential runs among 24 trauma service patients admitted to a surgical intensive care unit (2004-2005). RESULTS: Using point-of-care measurements, mean preinfusion BG was 230.0 +/- 67.9 mg/dL. BG < 140 mg/dL was reached during all 27 runs (median time 5.0 h), and target BG was < 110 mg/dL during 25 runs (median time 11.0 h). For the group of runs attaining target before interruption of insulin infusion, the average +/- SD of the principal measure of glycemic control, the within-run mean BG, was 113.7 +/- 14.8 mg/dL (coefficient of variation 13%, n = 25 runs). After attaining target, the average within-run SD for BG was 22.9 mg/dL. The within-run frequency of hypoglycemic measurements (BG < 70 mg/dL) as a percentage of BG determinations was 2.4%. In this series, no instance of BG <50 mg/dL was seen. CONCLUSIONS: This report describes a nurse-implemented tabular protocol for intravenous insulin infusion having the advantages of efficacy, safety, and simplicity of use. Wide variability of IR in the neighborhood of BG 110 mg/dL is associated with stable BG response, and protection against hypoglycemia is achieved by rapid decline of IR at BGs in or below the target range.

Sixteen-slice computed tomographic angiography is a reliable noninvasive screening test for clinically significant blunt cerebrovascular injuries.

BACKGROUND: In light of their potential for devastating consequences, a liberalized screening approach for blunt cerebrovascular injuries (BCVI) is becoming increasingly accepted. The gold standard for diagnosis of BCVI is arteriography (ART), but noninvasive diagnostic alternatives offer clear advantages. Prospective comparative studies found that computed tomographic angiography (CTA) was unreliable in detecting BCVI. However, with advanced CTA technology, it has become more difficult to justify ART in asymptomatic patients. We implemented a liberal screening protocol for BCVI, employing 16-slice CTA. We hypothesized that CTA would detect all clinically significant BCVI. METHODS: Patients undergoing computed tomography scanning for cranial or cervical trauma, as well as those with high-risk injury mechanisms or patterns, had craniocervical CTA performed. Abnormal CTA studies were confirmed with ART. Patients were followed for signs or symptoms of ischemic neurologic events. RESULTS: Over an 11-month period, 331 patients underwent CTA. Eighteen (5.4%) patients had a total of 20 BCVI. There were 11 carotid and 9 vertebral artery injuries. Seven of nine (78%) vertebral injuries were associated with cervical spine fractures. Two patients who did not meet screening criteria had signs or symptoms of BCVI before CTA. No patient with normal CTA developed evidence of BCVI. CONCLUSIONS: CTA detected all clinically significant injuries during this study period. Liberal screening with 16-slice CTA is appropriate and is likely to miss very few significant injuries. A multicenter trial will help to clarify risk factors and the accuracy of noninvasive diagnostic modalities.

Decellularized cadaver vein allografts used for hemodialysis access do not cause allosensitization or preclude kidney transplantation.

BACKGROUND: Dimethyl sulfoxide-cryopreserved (CRY) cadaver vein allografts used for hemodialysis access in patients with renal failure recently have been shown to cause broad recipient allosensitization, measured by panel reactive antibody (PRA) assay. Synergraft (SYN) processing is a novel method of treating tissue that decellularizes the graft (including mismatched major histocompatibility antigens) and potentially should prevent allosensitization. METHODS: Twenty hemodialysis patients underwent placement of an SYN-processed cadaver vein allograft. PRA assay was used prospectively to assess allosensitization in these patients at baseline and 1-month intervals after engraftment. These results were compared with our historic series of CRY allograft recipients. RESULTS: There was no significant difference in baseline PRA values for SYN and CRY patients (2.8% versus 2.6%, respectively). None of the SYN patients became allosensitized at 3 months postengraftment (mean PRA, 3.2%), whereas all CRY recipients became highly sensitized at a mean of 3.1 months (mean PRA, 84.1%). This result was highly significant (P < 0.0001). CONCLUSION: SYN processing of cadaver vein allografts successfully removes antigenic material. The use of SYN allografts in patients with renal failure for hemodialysis access does not cause allosensitization and therefore should not preclude kidney transplantation.

A novel technique designed to minimize the morbidity of failure of arteriovenous access in hemodialysis patients.

The failure of dialysis access grafts leads to significant morbidity rates in patients with end-stage renal disease. We describe a novel technique for the insertion of new polytetrafluoroethylene graft segments designed to reduce this morbidity rate. Patients found to have significant intragraft deterioration at thrombectomy undergo insertion of a new nonanastamosed graft parallel to the existing graft. At the next failure of the existing graft, the nonanastamosed segment is anastamosed and used immediately for dialysis, obviating the need for a temporary catheter. Thirty patients have undergone this technique, and 89% of those who returned to surgery have had successful anastamosis of their new segments. Two patients were found to have inadequate incorporation of their new segments into the subcutaneous tissue, and one became frankly infected.