Soluble fibrin monomer complex and cardiopulmonary bypass.

Soluble fibrin monomer complexes (SFMCs) are precursors of fibrin polymer formation. Laboratory tests can be used to detect SFMCs in plasma. The purpose of this study was to determine whether a positive SFMC test is associated with pre-operative, intra-operative, and post-operative variables for patients that have undergone cardiopulmonary bypass (CPB). Pre-operative, operative, post-operative, and laboratory data from 120 consecutive adults patients (July 3, 2006 to June 29, 2007) that had undergone cardiac surgery with the use of CPB were obtained from a prospective quality control database. Two groups were created. Group 1 was all negative (NEG). This group had no SFMC test with a positive result (n=60) and no positive SFMCs (POS, n=60). Group 2 was any positive (POS). This group had at least one positive SFMC test (n=60). The POS group had more patients with endocarditis (11.7% vs. 3.3%, p < .001), chronic obstructive pulmonary disease (COPD) (18% vs. 8.3%, p = .005), longer CPB time (172 +/- 64 vs. 151 +/- 53 minutes, p = .047), and fewer minimally invasive procedures (31.7% vs. 51.7%, p = .002). The POS group required intraoperative (70.0% vs. 53.3%, p = .010) and post-operative (75.5% vs. 45.0%, p < .001) transfusions more frequently than the NEG group, despite similar amounts of blood loss. SFMC tests in CPB may be associated with patient pre-operative status and an increase in transfusion requirements.

Autologous platelet gel: fad or savoir? Do we really know?

Autologous platelet-gel (APG) is the process of harvesting ones own cells (platelets), concentrating them most often through centrifugation, exposing them to an agonist which induces activation which releases intrinsic substances, and applying them to a target area to accelerate wound healing. APG is attractive because it concentrates a large number of biologically active substances, which are primarily proteins that participate in complex series of mechanisms involved in inflammation and wound healing. It has been used in numerous applications including sports medicine, dermatology, and surgery. However, there are few prospective randomized trials that have compared it in a rigorous manner to other techniques or to placebo. The following report is a review of APG, which includes a description of its perceived benefit, identification of the various modalities where it has been used, and criticisms concerning its use.

Factors that influence the ability to perform autologous priming.

The purpose of this study was to determine which factors impact the ability to perform autologous priming (AP) of the extracorporeal circuit. Second, the effects of differential AP on transfusion and volume requirements were evaluated. After institutional review board approval, demographic, operative, volumetric, and transfusion data were prospectively collected on 100 adult patients undergoing cardiopulmonary bypass (CPB). Two analyses were conducted: AP Taken and percent AP Given. For each analysis, three groups were created based on standard distribution. Group A included patients within less than mean--1 SD (< or = 500 mL AP Taken or > or = 90% AP Given back), group B included patients within mean +/- 1 SD (501-1299 mL AP Taken or 11%-89% AP Given back), and group C included patients greater than mean + 1 SD (> or = 1300 mL AP Taken or < or = 10% AP given back). Weight, pre-CPB hematocrit, clinical severity, and pre-CPB volume balance did not differ between the groups. Significant differences existed in AP Taken and percent AP Given between individual perfusionists. More AP was given back with higher urine output (group A: 846 +/- 700 mL, group B: 613 +/- 414 mL, group C: 384 +/- 272 mL; p = .004), more autotransfusion [group A: 0 (0,1300 mL), group B: 0 (0,500 mL), group C: 0 (0,250 mL); p = .008], and less AP Taken [group A: 800 (0,1300 mL), group B: 1000 (200,1600 mL), group C: 1000 (800,1600 mL); p = .001]. When more AP was taken, CPB hematocrit was higher (group A: 22.3% +/- 4.8%, group B: 25.6% +/- 4.7%, group C: 26.6% +/- 4.3%; p = .032), and fewer patients received red blood cells (group A: 64.3%, group B: 28.3%, group C:14.3%; p = .017). Some perfusionists were able to remove more AP before CPB. When more AP was taken, CPB hematocrit was higher, fewer patients received a transfusion, and less AP was given back. More AP was also given back with higher urine output and higher blood loss to the autotransfusion device.

A novel calculation to estimate blood volume and hematocrit during bypass.

Patient blood volume impacts most facets of perfusion care, including volume management, transfusion practices, and pharmacologic interventions. Unfortunately, there is a wide variability in individual blood volumes, and experimental measurement is not practical in the clinical environment. The purpose of this study was to evaluate a mathematical algorithm for estimating individual blood volume. After institutional review board approval, volumetric and transfusion data were prospectively collected for 165 patients and applied to a series of calculations. The resultant blood volume estimate (BVE) was used to predict the first and last bypass hematocrit. The estimated hematocrits using both BVE and 65 mL/kg were compared with measured hematocrits using the Pearson moment correlation coefficient and the Bland Altman measures of accuracy and precision. There was a wide range of BVE (minimum, 35 mL/kg; mean +/- SD, 64 +/- 22 mL/kg; maximum, 129 mL/kg). Using BVE, the estimated hematocrit was similar to the measured first (24.7 +/- 6.4% vs. 24.5 +/- 6.2%, r = 0.9884, p > .05) and last (24.5 +/- 5.9% vs. 25.1 + 5.7%, r = 0.9001, p > .05) bypass hematocrit. Using 65 mL/kg resulted in a larger difference between estimated and measured hematocrits for the first (25.6 +/- 4.5% vs. 24.5 +/- 6.2%, r = 0.6885, p = .030) and last (23.8 +/- 3.6% vs. 25.1 +/-5.7%, r = 0.5990, p = .001) bypass hematocrits. Compared with using 65 mL/kg for blood volume, the BVE allowed for a more precise estimated hematocrit during CPB.

Use of a multi-modality life support system.

The purpose of this study was to describe the design and utilization of a multi-modality life support system (MMLSS), which is used to provide extracorporeal support for cases such as left heart bypass (LHB), extracorporeal life support (ECLS), veno-venous bypass, and hypothermic resuscitation. The design of the MMLSS consisted of a mobile cart outfitted with a centrifugal pump, heater cooler, an in-line blood gas monitor, oxygen blender/flow meter, and assorted safety devices (pressure sensors and level and bubble detectors). A single disposable circuit was used for all procedures and designed to be easily modifiable to support a variety of clinical scenarios, with and without the use of an oxygenator. The system was designed for rapid deployment throughout the hospital. From January 1, 2006 to December 31, 2007, the MMLSS has been used in three LHB procedures (63 +/- 72 minutes), four adult ECLS cases (57.2 +/- 56.9 hours), four veno-venous bypasses (72 +/- 35 minutes), and one hypothermic resuscitation (182 minutes). The MMLSS was designed to be used in patients > 20 kg and could achieve flows in the range of 1-5.5 L. There were no complications associated with the device. The MMLSS is a versatile system that can be used throughout the hospital with a single disposable circuit, accommodating a diverse caseload in a safe and reproducible manner.

Characteristics of uncontrolled hemorrhage in cardiac surgery.

Patients with uncontrolled hemorrhage require massive transfusion therapy and consume a large fraction of blood bank resources. Institutional guidelines have been established for treatment, but early identification and prevention in susceptible patients remains challenging. Uncontrolled hemorrhage was defined as meeting institutional guidelines for recombinant FVIIa administration. Patients who received rFVIIa were compared with patients who did not require the therapy but who were operated on during the same time period. After institutional review board approval, demographic, operative, and transfusion data were analyzed from a prospective database. Patients receiving rFVIIa were more likely to undergo multiple procedures (2.6 +/- 0.8 vs. 1.8 +/- 0.8; p < .001); aortic surgery (59% vs. 11%; p < .005); have a higher Cleveland Clinic Clinical Severity score (7.8 +/- 2.7 vs. 5.5 +/- 4.0; p < .005); require longer bypass (265 +/- 92 min vs. 159 +/- 63 min; p < .001), cross-clamp (182 +/- 68 min vs. 112 +/- 56 min; p < .001), and circulatory arrest (15 +/- 24 min vs. 2 +/- 7 min; p < .05) times; and require more autotransfusion (2580 +/- 1847 mL vs. 690 +/- 380 mL; p < .05). Uncontrolled hemorrhage is associated with more complex surgery requiring longer bypass times and more autotransfusion.