BioGlue surgical adhesive for thoracic aortic repair during coagulopathy: efficacy and histopathology.

BACKGROUND: We hypothesized that induction of coagulopathy in sheep would model clinical needle hole and surgical bleeding from synthetic graft anastomoses, and that a new tissue bioadhesive (BioGlue) would control postoperative blood loss during surgical repair of the thoracic aorta. METHODS: Sheep were anticoagulated with aspirin and heparin. A bypass was made using end-to-side anastomoses of a graft to a partially occluded descending thoracic aorta. Experimental anastomoses (EXP, n = 9) were treated with BioGlue, and control anastomoses (CON, n = 5) were treated with Surgicel to gain intraoperative hemostasis. RESULTS: EXP animals exhibited significantly reduced postsurgical bleeding (CON median 955 mL versus EXP median 470 mL, p < 0.003), a reduced rate of blood loss over the first 2 postoperative hours (CON median 210 mL/hr versus EXP median 92.5 mL/hr, p < 0.006), and over the entire recovery period (CON median 158 mL/hr versus EXP median 86 mL/hr, p < 0.05), and reduced total blood loss (CON mean 1,497 +/- 691 mL versus EXP mean 668 +/- 285 mL, p < 0.008). On histologic examination of tissues explanted after 3 months, BioGlue was relatively inert and demonstrated a minimal inflammatory response. CONCLUSIONS: The use of BioGlue significantly reduced the volume and rate of postsurgical bleeding in a coagulopathic sheep model for thoracic aortic operations. Histopathologically, BioGlue generated only a minimal inflammatory response. This new surgical tissue bioadhesive should prove extremely beneficial for coagulopathic patients undergoing thoracic aortic or vascular procedures.

A novel technique in a sheep model for evaluating prosthetic heart valve performance.

There have been many various animal studies to evaluate the structural integrity and antithrombogenicity of prosthetic heart valves. We were interested in developing a novel sheep model to study the thrombogenicity of mechanical heart valves placed into the systemic circulation but without the need for cardiac bypass. Also, we wanted to minimize the risk ofparaplegia from complete thoracic aortic clamping. Six sheep underwent left lateral thoracotomy for placement of a mechanical heart valve in parallel with the descending thoracic aorta. A valved conduit with a dacron tube graft sutured to the back end was fashioned. Employing partial aortic occlusion with a side-biting clamp, the proximal and distal ends were anastomosed in an end-to-side fashion. Once flow was confirmed through the graft, the native aorta was occulded with umbilical tape. The sheep received no postoperative anticoagulation. The median operative time and estimated blood loss (EBL) was 170 min and 250 cc, respectively. Patency of the valved conduits was confirmed during the initial procedure, and there was no incidence of paraplegia postoperatively. Two animals expired shortly after extubation and at necropsy the valved conduits were patent with preserved valve function. The four survivors were sacrificed a median of 37 days postoperatively. Prior to euthanasia, the valved conduits were evaluated in situ with ultrasound. In all cases, the valves had clot formation at the hinges, which prevented active movement of the leaflets. This novel in vivo technique provides an alternative in testing the thrombogenicity of prosthetic heart valves without cardiac bypass or the risk of paraplegia in an animal that is extremely sensitive to complete aortic cross-clamp.

Hemangioma of the right ventricular outflow tract.

Obstruction of the right ventricular outflow tract by a primary cardiac tumor is rare. Six cases of right ventricular outflow tract obstruction by a primary cardiac hemangioma have been reported; all but one were detected before the age of 25 years. In this report, we review the literature and describe what we believe to be only the second reported case of right ventricular outflow tract obstruction produced by a cardiac hemangioma that presented in late adulthood.

A sheep model for thoracic aortic surgery in the presence of systemic coagulopathy.

Surgical repair of aneurysms, traumatic injuries, or congenital anomalies of the thoracic aorta are associated with high morbidity and mortality mainly as a result of excessive and uncontrollable hemorrhage from diffuse coagulopathy. We developed a model in sheep that simulates this coagulopathic state for experimentation with thoracic aorta surgery. This experimental animal model involves administering a 600-mg aspirin suppository once a day for the 2 days preceding surgery and a final dose on-call to surgery. Prior to cross-clamping the aorta, an intravenous (i.v.) bolus of heparin (400 IU/kg) was administered. Thirty minutes later, the i.v. heparin bolus was repeated. Pre- and intraoperative activated clotting time was 101 +/- 10 s and >1500 s (p < .0001); prothrombin time, 21 +/- 1 s and >100 s (p < .0001); and activated partial thromboplastin time, 20 +/- 1 s and >50 s (p < .0001), respectively. We utilized a partial cross-clamp-and-sew technique to anastomose a woven, gelatin-impregnated, 16-mm tube graft end-to-side to the descending thoracic aorta. Mean total blood loss was 1367 +/- 282 mL, which included mean blood loss from time of release of aortic cross-clamp to close (422 +/- 135 mL) and mean total blood output from chest tube drain (945 +/- 203 mL). The mean time to achieve hemostasis at suture lines after aortic cross-clamp release was 15.5 +/- 6.6 min. In conclusion, a sheep model with induced coagulation defects was successfully developed and reproducible for experimentation involving thoracic aortic surgery.

Transmyocardial laser revascularization combined with coronary artery bypass grafting: a multicenter, blinded, prospective, randomized, controlled trial.

OBJECTIVE: We sought to assess the safety and efficacy of transmyocardial revascularization combined with coronary artery bypass grafting in patients not amenable to complete revascularization by coronary bypass alone. METHODS: A total of 263 patients whose standard of care was coronary artery bypass grafting and who had one or more ischemic areas not amenable to bypass grafting were prospectively randomized to receive coronary bypass of suitable vessels plus transmyocardial revascularization to areas not graftable (n = 132) or coronary bypass alone with nongraftable areas left unrevascularized (n = 131). Group preoperative demographics and operative characteristics were similar. RESULTS: The operative mortality rate after coronary bypass/transmyocardial revascularization was 1.5% (2/132) versus 7.6% (10/131) after coronary bypass alone (P =.02). Patients undergoing both coronary bypass and transmyocardial revascularization required less postoperative inotropic support (30% vs 55%, P =.0001) and had a trend toward fewer insertions of intra-aortic balloon pumps (4% vs 8%, P =.13) than did patients having coronary bypass alone. Multivariable predictors of operative mortality were coronary artery bypass alone (odds ratio, 5.3; 95% confidence interval, 1.1-25.7; P =.04) and increased age (odds ratio, 1.1; 95% confidence interval, 1. 0-1.2; P =.03). One-year Kaplan-Meier survival (95% vs 89%, P =.05) and freedom from major adverse cardiac events defined as death or myocardial infarction (92% vs 86%, P =.09) favored the combination of coronary bypass and transmyocardial revascularization. Baseline to 12-month improvement in angina and exercise treadmill scores was similar between groups. CONCLUSIONS: In a prospective, randomized, multicenter trial, transmyocardial revascularization combined with coronary artery bypass grafting in patients not amenable to complete revascularization by coronary bypass alone was safe; however, angina relief and exercise treadmill improvement were indistinguishable between groups at 12 months of follow-up. Operative and 1-year survival benefits observed after adjunctive transmyocardial revascularization require confirmation by a larger validation study, which is ongoing.

Vascularized bone marrow transplantation: A new surgical approach using isolated femoral bone/bone marrow.

BACKGROUND: Orthotopic composite tissue (limb) transplantation in rats is a unique model for vascularized bone marrow transplantation because bone marrow cells and bone marrow stroma are transplanted by microsurgical means, thus creating immediate bone marrow space and engraftment. However, it contains a skin component and other musculoskeletal tissues that complicate issues related to tolerance induction. MATERIALS AND METHODS: To study only aspects of vascularized bone marrow transplantation, we created a new isolated vascularized bone marrow transplant model in rats. The common iliac (or femoral) artery and vein were microsurgically anastomosed to the recipient abdominal aorta and inferior vena cava in an end-to-side fashion, respectively. Syngeneic male Lewis (RT1(1), n = 20) and allogeneic male BN (RT1(n), n = 10) donors were transplanted to female Lewis recipients. To establish rejection criteria, we examined histopathology and used the polymerase chain reaction (PCR) to assess microchimerism of donor male bone marrow cells in the peripheral blood of female recipients using rat Y chromosome (sex-determining region Y)-specific primers. RESULTS: All recipients were healthy and remained stable without major complications for up to 300 days posttransplant. Morphologically, syngeneic male Lewis bone marrow showed a near-normal appearance. Allogeneic male BN bone marrow was clearly rejected. Male bone marrow cells were detected by PCR in the peripheral blood of all syngeneic recipients, but not in allogeneic blood specimens. CONCLUSIONS: A new surgical approach to bone marrow transplantation was established. This consisted of the vascularized femoral bone/bone marrow transplant. Further analyses regarding the ability of vascularized femoral bone marrow transplants to induce systemic transplantation tolerance in adult rats will provide insights into not only various issues of immunology but also the potential clinical application of vascularized bone marrow transplantation.

Transmyocardial laser revascularization: current status.

Transmyocardial laser revascularization (TMLR) has been widely evaluated for treatment of the ischemic myocardium either in conjunction with coronary artery bypass grafting or as sole therapy. Clinically, it has shown significant improvement for angina symptoms, but the mechanism by which this modality works is unknown at this time. The original premise on which transmyocardial revascularization was established depended on its ability to essentially generate channels that would directly carry blood from the ventricle into the ischemic myocardium. This theory, however, has not been substantiated, so other mechanisms have been postulated. This article gives a historical perspective on the advent of transmyocardial revascularization and the many animal and human studies that have paved the way for its clinical use. Current controversies are examined, along with the new advances in laser technology and where the future of TMLR is headed.

An in vivo evaluation of a chondroitin sulfate solution to prevent postoperative intraperitoneal adhesion formation.

PURPOSE: The goal of this study was to determine the efficacy of a single intraperitoneal administration of a chondroitin sulfate solution in preventing postoperative adhesion formation. METHODS. Twenty-five Sprague-Dawley rats had a 1-cm(2) area of cecal serosa abraded. Controls (CON, n = 5) received no treatment, the chondroitin sulfate group (CS, n = 10) received chondroitin sulfate (0.013 g/kg) in 0.9% NaCl intraperitoneally (ip), and vehicle controls (VC, n = 10) received an equal volume of 0.9% NaCl solution ip before the abdomen was closed. All animals were sacrificed on postoperative day 10. The extent of adhesion was quantified according to Mazuji's adhesion grade (0 to 4: 0 = no adhesion and 4 = very dense adhesion) and quantitated after H&E, trichome, and immunohistochemical staining for fibrin and collagen type I and type III using digital image analysis. RESULTS: The mean Mazuji's adhesion grade in the CON was 4.0 +/- 0.0, in the VC 2.60 +/- 0.37, and in the CS 1.3 +/- 0.42 (P < 0.01 for CS vs CON and P < 0.05 for CS vs VC comparisons). The mean gray-scale intensity (0-255: 0 = dense amount and 255 = none) of adhesion density in the CON was 105. 5 +/- 5.5, in the VC 125 +/- 15.0, and in the CS 178.3 +/- 21.0 (P < 0.01 for CS vs CON and P < 0.05 for CS vs VC comparisons). The mean adjusted intensity stain indices (AISI) for fibrin and collagen type I in the CON were 59 +/- 17 and 53 +/- 19, in the VC 27 +/- 3 and 25 +/- 7, and in the CS 16 +/- 5 and 6 +/- 3, respectively (P < 0.05 between CS and CON comparisons). The AISI of collagen type III was not significant among all the groups (P > 0.1). CONCLUSIONS: The extent of early postoperative intra-abdominal adhesion formation as determined by gross assessment and from quantitation of fibrin and collagen type I deposition was significantly reduced by a single intraperitoneal administration of a chondroitin sulfate solution.

Diamond-like carbon coating and plasma or glow discharge treatment of mechanical heart valves.

All mechanical heart valves (MHV) are thrombogenic. Application of surface modification technology to reduce the incidence of thrombus formation on MHV is a novel undertaking. This requires collaboration within the bioengineering and cardiothoracic surgery fields. From reviewing results of recent and past investigations, and our own preliminary study with diamond-like carbon coating (DLC) and plasma or glow discharge treatment (GDT) of MHV, we identify and discuss several potentially beneficial effects that may reduce the extent of valve-related thrombogenesis by surface modification. DLC and GDT may affect the surfaces of MHV in many ways, including cleaning of organic and inorganic debris, generating reactive and functional groups on the surface layers without affecting their bulk properties, and making the surfaces more adherent to endothelial cells and albumin and less adherent to platelets. These different effects of surface modification, separately or in combination, may transform the surfaces of MHV to be more thromboresistant in the vascular system.

Rat renal allograft tolerance is associated with local TGF-beta and absence of IL-2r expression within chimeric immunocytic foci.

Tolerance was induced in Lewis (LEW) rat renal allograft recipients of Brown Norway kidneys by multiple pretransplant donor-blood transfusions and prior limited cyclosporine A. Rat renal allograft tolerance was associated with the induction of systemic donor T cells (10%), an early phase of nonspecific suppressor-cell generation, followed by maturation of systemic antigen-specific suppressor cells, and renal cellular infiltrates that develop long-term in situ in the kidney graft model. It was hypothesized that these infiltrates represent chimeric immunocytic foci that are locally regulated via a TGF-beta-dependent mechanism. Both immunohistochemical staining and digital image analysis for cellular and extracellular TGF-beta, IL-2 receptor (CD25), and the BN Class I-MHC marker (OX-27) were performed. Control rejecting (REJ) kidneys did not demonstrate any differences with respect to levels of infiltrating immunocyte area vs long-term surviving (TOL) kidneys (3.9% vs 4.5%, P = .303). Immunostaining with the BN Class I MHC marker (OX-27) demonstrated high levels of chimerism within immunocyte foci of the tolerant grafts (OX-27 BN+immunocytes 49.0% +/- 5.1%). In situ cellular IL-2 receptor (CD25) expression was demonstrated in REJ kidney infiltrates but not within TOL immunocytic infiltrating foci, when measured as percent of total lymphocytes (REJ = 5.0% vs TOL = 0.4%, P = .031). Conversely, TGF-beta expression was significantly higher in immunocytes of TOL kidneys when measured as the number of DAB chromogen-staining pixels per total immunocyte area (TOL = .076 vs REJ = .047, P = .003). In conclusion, these results suggested that stable mixed immune chimerism (SMIC) plays an important role in DST-CyA-induced tolerance in situ. SMIC-induced tolerance may involve a local TGF-beta-dependent mechanism that is associated with in situ TGF-beta (+) and IL-2r (-) immunocytes.

In vivo measurement of lung preservation solution efficacy: comparison of LPD, UW, EC and low K+-EC following short and extended ischemia.

OBJECTIVE: The impact of storage solution composition on graft performance was evaluated following perfusion with either Euro-Collins (EC), low potassium Euro-Collins (rEC), low potassium dextran (LPD) or University of Wisconsin solution (UW) after brief (2 h) and extended ischemia (16 h) in an acute double lung transplantation model in the rat. METHODS: Following flush perfusion and ischemia the lungs were implanted in recipient rats allowing serial assessment of graft pulmonary vascular resistance (PVR) and alveolar arterial oxygen difference (AaDO2) during 120 min of reperfusion. Graft dynamic lung compliance (DLC) was determined by separate ventilation. Final evaluation included weight gain and histology. RESULTS: After extended ischemia LPD provided superior graft function in respect to DLC (repeated measures ANOVA; LPD versus rEC P < 0.05; versus EC P < 0.03; versus UW P < 0.05) and AaDO2 (LPD versus rEC P < 0.04; versus EC P < 0.006). The PVR was significantly lower in LPD versus UW (P < 0.05). At the end of reperfusion the weight increase amounted to 229 +/- 49% in rEC, 207 +/- 22% in EC, 115 +/- 22% in UW and 87 + 17% in LPD (LPD versus rEC P < 0.01, LPD versus EC P < 0.001). The type of preservation solution used had little impact on graft function after 2 h ischemia. CONCLUSIONS: Low potassium dextran provides superior graft function after extended ischemia. After short ischemia the type of preservation solution used in this study had little impact on global lung function.

Lorazepam and midazolam in the intensive care unit: a randomized, prospective, multicenter study of hemodynamics, oxygen transport, efficacy, and cost.

OBJECTIVES: To evaluate and compare the clinical efficacy, impact on hemodynamic and oxygen transport variables, safety profiles, and cost efficiency of sedation and anxiolysis with lorazepam vs. continuous infusion of midazolam in critically ill, intensive care unit patients. DESIGN: Multicenter, prospective, randomized, open-label study. SETTING: Teaching hospitals. PATIENTS: Ninety-five critically ill, mechanically ventilated patients with fiberoptic pulmonary artery catheters in place were randomly assigned to receive short-term (8 hrs) sedation with either intermittent intravenous injection lorazepam (group A, n = 50) or continuous intravenous infusion midazolam (group B, n = 45) titrated to clinical response. MEASUREMENTS AND MAIN RESULTS: The severity of illness, demographic characteristics, levels of anxiety and agitation, hemodynamic parameters, oxygen transport variables, quality of sedation, nursing acceptance, and laboratory chemistries reflecting drug safety were recorded. There were no significant differences with regard to demographic data, hemodynamic and oxygen transport variables, or levels of anxiety/agitation between the two groups at baseline, 5 mins, 30 mins, and 4 and 8 hrs after administration of sedation. There were no significant differences in the quality of sedation or anxiolysis. Midazolam-treated patients used significantly larger amounts of drug for similar levels of sedation and anxiolysis (14.4 +/- 1.2 mg/8 hrs vs. 1.6 +/- 0.1 mg/8 hrs, p = .001). Both drugs were safely administered and patient and nurse satisfaction was similar. CONCLUSIONS: Sedation and anxiolysis with lorazepam and midazolam in critically ill patients is safe and clinically effective. Hemodynamic and oxygen transport variables are similarly affected by both drugs. The dose of midazolam required for sedation is much larger than the dose of lorazepam required for sedation, and midazolam is therefore less cost-efficient.

Comparison of antegrade with antegrade/retrograde cold blood cardioplegia for myocardial revascularization.

There has been increasing interest in the use of retrograde coronary sinus perfusion for delivery of cardioplegic solution during myocardial revascularization. Despite evidence of improved cardiac protection, it is unclear if a combined antegrade/retrograde approach to myocardial preservation offers significant clinical benefits. One hundred twenty patients undergoing elective 1st-time coronary bypass surgery for 3-or-more-vessel disease received aortic root, antegrade cold blood cardioplegia (Group I, n=52) or combined antegrade/retrograde cardioplegia via coronary sinus cannulation (Group II, n=68). All preoperative variables were similar, including age, severity of coronary artery disease, functional status, and ejection fraction. Intraoperative and postoperative variables, including the degree of hypothermia, temperature of infusion solution, number of bypass grafts, defibrillation attempts and spontaneous return to sinus rhythm, the use of intraaortic balloon pump counterpulsation, and inotropic support during weaning from cardiopulmonary bypass, were not statistically different. Cardioplegia infusion time was longer in Group II than in Group I (2.5 +/- 0.8 vs 1.7 +/- 0.7 min, p < 0.05). The postoperative cardia output, electrocardiographic and cardiac enzyme evidence of ischemia, the need for temporary pacing, and 30-day morbidity were similar for both groups. The data indicate that in this non-risk-stratified group of patients, the route of cardioplegia administration is not a determinant of clinical outcome.

Descending thoracic aortomyoplasty: a technique for clinical application.

BACKGROUND: Descending thoracic aortomyoplasty is a form of skeletal muscle-powered cardiac assistance. Its use in clinical settings has been limited by the ligation of intercostal arteries necessary to complete a circumferential wrap of the aorta with the latissimus dorsi. METHODS: This study assessed the feasibility and the efficacy of aortomyoplasty constructed with a modified latissimus dorsi. A pericardial patch was attached to the latissimus dorsi and divided around the preserved intercostal arteries. Nine alpine goats (37 +/- 2 kg) underwent descending aortomyoplasty using this technique. All intercostal arteries were preserved. After a 6-week recovery period, the animals underwent a 6-week, incremental electrical conditioning program. After 90 postoperative days, animals were examined under anesthesia with the myostimulator on and off. RESULTS: Aortomyoplasty activation resulted in augmentation of mean diastolic aortic pressure by 16.0 +/- 0.9 mm Hg (23%). Significant improvements in cardiac index (40%), stroke volume index (37%), left ventricular stroke work index (49%), and mean arterial pressure (19%) were noted. An intravascular sonographic probe placed in the descending aorta revealed circumferential compression of the aorta during counterpulsation. Mean cross-sectional aortic area was reduced by 51.8%, from 210.1 +/- 7.1 to 108.9 +/- 6.7 mm2 during aortomyoplasty activation (p < 0.05). Histologic analysis confirmed the long-term patency of intercostal arteries. CONCLUSIONS: Descending aortomyoplasty, modified with an interposing patch of pericardium, effectively transfers skeletal muscle force across the aortic wall and assists cardiac function. This technique allows preservation of all aortic branches, and with this novel approach, the clinical utility of aortomyoplasty can now be explored.

Predictors of stroke after cardiac surgery.

From January 1, 1988 to September 30, 1993, 44 of 2,455 patients undergoing cardiac surgery for acquired heart disease at our institution sustained an intraoperative or postoperative cerebrovascular accident (CVA). Demographic data, atherosclerosis risk factors, past medical history, cardiac catheterization reports, and intraoperative findings were retrospectively reviewed. The highest rate of CVA was in the sub-group of patients undergoing simultaneous myocardial revascularization and carotid endarterectomy (18.2%). The lowest rate was in a group of patients who underwent aortic valve replacement (0.9%). Severe aortic arch atherosclerosis with the presence of atheromatous material or calcinosis at the cannulation site was identified intraoperatively in 43.2% of patients with neurological complications and in 5% of the group without CVA (x2 = 18.1, p = 0.0001). Of 44 patients with CVA, 13.6% had a history of preoperative completed stroke. CPB time was 90.1 +/- 4.9 min vs. 71.6 +/- 3.7 min (p = 0.004), and aortic cross-clamping time was 54.5 +/- 3.2 min compared to 39.8 +/- 2.7 min (p = 0.001) in groups with and without postoperative stroke, respectively. Hypertension was an independent risk factor of postoperative CVA (x2 = 9.5, p = 0.02), but age was not. Neurological complications correlated with high operative mortality (38.6%) and prolonged postoperative hospital stays (35.1 +/- 5.3). These data describe predictors for the development of post-cardiopulmonary bypass CVA and identify a high-risk subgroup for neurological events. The preoperative recognition of risk factors is an essential step toward the reduction of morbidity and mortality.

Latissimus dorsi and serratus anterior dynamic descending aortomyoplasty for ischemic cardiac failure.

Dynamic descending aortomyoplasty for cardiac assistance is a form of extraaortic, skeletal muscle-driven counterpulsation. Controversy exists regarding its clinical applicability and the most suitable muscle autograft for the procedure. Specifically, the ligation of intercostal vessels required for descending aortomyoplasty may not be tolerated clinically. This study compared the hemodynamic profiles and long-term function of latissimus dorsi (LD) aortomyoplasty to a split serratus anterior (SA) descending aortomyoplasty in which all intercostal vessels were preserved. Descending aortomyoplasty was performed in 11 goats. In 5, the SA was harvested and its distal end divided, facilitating a wrap of the aorta without ligation of intercostal arteries. In 6, the LD was used as a circumferential aortic wrap. At 90 days, an occluder placed on the left anterior descending artery created an ischemic event. Hemodynamic studies with and without assistance were performed in the ischemic and nonischemic states. Latissimus dorsi aortomyoplasty improved cardiac output 24% and 5.6%, stroke volume 29% and 66%, left ventricular stroke work index 30% and 166%, and coronary flow 4% and 3% in the normal and ischemic heart, respectively. Serratus anterior aortomyoplasty improved cardiac output 36% and 10%, stroke volume 42.8% and 13.5%, left ventricular stroke work index 64% and 21%, and coronary flow 8% and 4.3%, in the normal and ischemic heart, respectively. Two of the SA autografts were fibrotic and nonfunctional at 3 months. Aortomyoplasty with either SA or LD muscle improves cardiac function in the normal and ischemic heart. However, divided SA is associated with a higher rate of fibrosis and may be less suitable for the procedure.

Determination and comparison of heat exchange efficiency of four commercially available blood cardioplegia sets.

An in vitro comparison of the heat exchange properties of the Electromedics D1081A, Sarns MP-4 'Conducer Coil' 165720, Bentley HE-100 and the Shiley BCD Plus 4: 1 blood cardioplegia sets was performed. The efficiency was calculated for each heat exchanger and post-heat exchange blood path temperatures were compared. The calculated efficiency for each heat exchanger is as follows: Electromedics D1081A at 18 l/minute coil water flow (0.95); Sarns MP-4 165720 at 9 l/minute coil water flow (0.93); Bentley HE-100 at 10 l/minute coil water flow (0.91); Shiley BCD Plus at 15 l/minute coil water flow (0.90). Blood path, precoil temperatures for each unit were compared statistically with no differences found (p > 0.05). Blood side, postcoil temperatures were then compared. The average postcoil blood path temperature of the Electromedics D1081A was 1.6 degrees +/- 0.1 degree C, of the Sarns MP-4 165720 it was 2.1 degrees +/- 0.1 degree C, of the Bentley HE-100 it was 2.7 degrees +/- 0.3 degree C, and the Shiley BCD Plus 3.0 degrees +/- 0.4 degree C. The results of this experiment indicate that the average postcoil temperature of the Electromedics D1081A was lower than the Sarns MP-4 165720 (p < 0.05) which was lower than that of the Bentley HE-100 (p < 0.05) and Shiley BCD Plus (p < 0.05). No statistical difference was found between the average postcoil temperature of the Bentley HE-100 and the Shiley BDC Plus.