Unusual complications after rewarming for deep accidental hypothermia.

Deep accidental hypothermia is an uncommon pathology. Successful management has been reported in isolated cases, but the majority of patients die from complications after rewarming. We report on a patient with deep accidental hypothermia after a mountaineering accident. He was successfully rewarmed with cardiopulmonary bypass, but presented several complications which led to death. These complications included the patient developing acute peritonitis and necrotizing fasciitis, which represent, to our knowledge, complications that have never been associated with deep accidental hypothermia before.

Off-pump coronary artery bypass surgery: physiology and anaesthetic management.

Increasing interest is being shown in beating heart (off-pump) coronary artery surgery (OPCAB) because, compared with operations performed with cardiopulmonary bypass, OPCAB surgery may be associated with decreased postoperative morbidity and reduced total costs. Its appears to produce better results than conventional surgery in high-risk patient populations, elderly patients, and those with compromised cardiac function or coagulation disorders. Recent improvements in the technique have resulted in the possibility of multiple-vessel grafting in all coronary territories, with a graft patency comparable with conventional surgery. During beating-heart surgery, anaesthetists face two problems: first, the maintenance of haemodynamic stability during heart enucleation necessary for accessing each coronary artery; and second, the management of intraoperative myocardial ischaemia when coronary flow must be interrupted during grafting. The anaesthetic technique is less important than adequate management of these two major constraints. However, experimental and recent clinical data suggest that volatile anaesthetics have a marked cardioprotective effect against ischaemia, and might be specifically indicated. OPCAB surgery requires team work between anaesthetists and surgeons, who must be aware of each other's constraints. Some surgical aspects of the operation are reviewed along with physiological and anaesthetic data.

[The heart transplant in Lausanne from 1987 to 2003]. / La greffe cardiaque à Lausanne de 1987 à 2003.

Since the availability of ciclosporine, the survival after heart transplantation has dramatically improved. We present our results since the beginning of our experience in 1987. We treated in the Lausanne University hospital, 150 patients for end-stage cardiac disease. Hundred and fifty-two transplantations were performed. The survival rate is comparable to the literature with 81% at one year, 70% at five year and 63 at ten year included the hospital mortality. We review the incidence of complications during the follow-up and report the modification in the management of these patients especially concerning the immunosuppression.

Poly2-methoxyethylacrylate (PMEA) coated oxygenator: an ex vivo study.

UNLABELLED: PMEA is a hydrophilic polymer coating with a unique design that minimizes the adsorption and denaturation of proteins and blood cells. This study compares thrombus resistance, blood path resistance, thrombocyte profile, and blood trauma of the PMEA coated Capiox membrane oxygenator (Terumo, Japan) vs. an uncoated version. METHOD: Six calves (mean bodyweight: 75.3 +/- 4.5kg) were placed on cardiopulmonary bypass for 6 hours and randomly assigned to the coated or uncoated oxygenator, with a low heparinisation protocol (ACT > 180s). RESULTS: Macroscopically, red staining was observed in all uncoated oxygenators, and in none of the coated ones. Inlet pressure was significantly higher in the uncoated group (at 1 h: 279 +/- 25 vs. 175 +/- 11mmHg, p < 0.01 and at 6h: 217 +/- 10 vs. 171(8mmHg, p < 0.01). Thrombocyte count values (corrected for hematocrit and normalized by prebypass values) were significantly higher in the coated group (at 1 h: 76 +/- 6 vs. 53 +/- 13%, p < 0.01 and at 6 h: 70 +/- 6 vs. 44 +/- 26%, p < 0.01). Plasma hemoglobin was below 100mg/L in both groups throughout the experiments. CONCLUSIONS: When compared with uncoated oxygenator, PMEA coated oxygenator exhibited increased thrombus resistance with lower inlet pressure and lower thrombocyte consumption. In both groups, trauma to red cells was minimal, emphasizing the efficient design of this type of oxygenator.

A new expandable cannula to increase venous return during peripheral access cardiopulmonary bypass surgery.

Peripheral cannulation for cardiopulmonary bypass (CPB) is of prime interest in minimally invasive open heart surgery. As CPB is initiated with percutaneous cannulae, venous drainage is impeded due to smaller vessel and cannula size. A new cannula was developed which can change shape in situ and therefore may improve venous drainage. An in vitro circuit was set-up with a penrose latex tubing placed between the preload reservoir and the cannula, encasing the cannula's inlet and simulating the vena cava. The preload (P) was stabilised at 2 and at 5 mmHg respectively. The maximum flow rate was determined for 4 conditions: passive venous drainage (PVD) and assisted venous drainage (AVD) using a centrifugal pump at the 2 preload settings. We compared the results of the prototype cannula to classical femoral venous cannulae: basket 28Fr, a thoracic 28Fr and a percutaneous 27Fr. Under PVD conditions and a CVP of 2 mmHg, the prototype cannula's flow rate outperformed the next best cannula by 14% (p=0.0002) and 13% under AVD conditions (p=0.0001). Under PVD conditions and a CVP of 5 mmHg, the prototype cannula outperformed the percutaneous cannula by 19% (p=0.0001) and 14% under AVD conditions (p=0.0002). The new cannula outperforms the classical percutaneous venous cannulae during all of the four conditions tested in vitro.

Adaptive support ventilation for fast tracheal extubation after cardiac surgery: a randomized controlled study.

BACKGROUND: Adaptive support ventilation (ASV) is a microprocessor-controlled mode of mechanical ventilation that maintains a predefined minute ventilation with an optimal breathing pattern (tidal volume and rate) by automatically adapting inspiratory pressure and ventilator rate to changes in the patient's condition. The aim of the current study was to test the hypothesis that a protocol of respiratory weaning based on ASV could reduce the duration of tracheal intubation after uncomplicated cardiac surgery ("fast-track" surgery). METHODS: A group of patients being given ASV (group ASV) was compared with a control group (group control) in a randomized controlled study. After coronary artery bypass grafting during general anesthesia with midazolam and fentanyl, patients were randomly assigned to group ASV or group control. Both protocols were divided into three predefined phases, and weaning progressed according to arterial blood gas and clinical criteria. In phase 1, ASV mode was set at 100% of the theoretical value of volume/minute in group ASV, and synchronized intermittent mandatory ventilation mode was used in group control. When spontaneous breathing occurred, ASV setting was reduced by 50% of minute ventilation (phase 2) and again by 50% (phase 3), and the trachea was extubated. In group control, the ventilator was switched to 10 cm H2O inspiratory pressure support (phase 2), then to 5 cm H2O (phase 3) until extubation. RESULTS: Forty-nine patients were enrolled. Sixteen patients completed the ASV protocol, and 20 the standard protocol; 7 patients were excluded in group ASV and 6 in group control according to explicit, predefined criteria. There were no differences between groups in perioperative characteristics or in the doses of sedation. The primary outcome of the study, that is, the duration of tracheal intubation, was shorter in group ASV than in group control (median [quartiles]: 3.2 [2.5-4.6] vs. 4.1 [3.1-8.6] h; P < 0.02). Fewer arterial blood analyses were performed in group ASV (median number [quartiles]: 3 [3-4] vs. 4 [3-6]), suggesting that fewer changes in the settings of the ventilator were required in this group. CONCLUSIONS: A respiratory weaning protocol based on ASV is practicable; it may accelerate tracheal extubation and simplify ventilatory management in fast-track patients after cardiac surgery. The evaluation of potential advantages of the use of such technology on patient outcome and resource utilization deserves further studies.

Vacuum assisted venous drainage does not increase trauma to blood cells.

Although gravity drainage has been the standard technique for cardiopulmonary bypass (CPB), the development of min imally invasive techniques for cardiac surgery has renewed interest in using vacuum assisted venous drainage (VAVD) Dideco (Mirandola, Italy) has modified the D903 Avant oxygenator to apply a vacuum to its venous reservoir. The impact of VAVD on blood damage with this device is analyzed. Six calves (mean body weight, 71.3 +/- 4.1 kg) were con nected to CPB by jugular venous and carotid arterial cannu lation, with a flow rate of 4-4.51 L/min for 6 h. They were assigned to gravity drainage (standard D903 Avant oxygen ator, n = 3) or VAVD (modified D903 Avant oxygenator, n = 3). The animals were allowed to survive for 7 days. A standard battery of blood samples was taken before bypass, throughout bypass, and 24 h, 48 h, and 7 days after bypass. Analysis of variance was used for repeated measurements. Thrombocyte and white blood cell counts, corrected by hematocrit and normalized by prebypass values, were not significantly different between groups throughout all study periods. The same holds true for hemolytic parameters (lactate dehydrogenase [LDH] and plasma hemoglobin). Both peaked at 24 hr in the standard and VAVD groups: LDH, 2,845 +/- 974 IU/L vs. 2,537 +/- 476 IU/L (p = 0.65), respectively; and plasma hemoglobin, 115 +/- 31 mg/L vs. 89 +/- 455 mg/L (p = 0.45), respectively. In this experimental setup with prolonged perfusion time, VAVD does not increase trauma to blood cells in comparison with standard gravity drainage.

Is an endocardial connection necessary for growth factor induced angiogenesis in transmyocardial laser revascularization?

Transmyocardial laser revascularization (TMLR) and therapeutic angiogenesis had emerged as potential tools in the treatment of angina refractory to conventional therapies. This combination might potentiate their effects, because angiogenesis is believed to be a basic mechanism in TMLR. The influence of channel connection with endocardial blood flow on angiogenesis is unclear. Twenty-five pigs (mean weight, 72.3 +/- 5 kg) were randomly assigned into five groups. In the transmural laser group, five transmyocardial channels were drilled. In the transmural mixed group, the same protocol was used followed by the injection of 100 microg of bovine bone derived growth factor mixture within each channel. The nontransmural laser group and the nontransmural mixed group underwent the same procedures, respectively, but the laser channels were drilled through the outer two-thirds of the myocardial wall. The control group had sham operations. Animals were allowed to survive for 1 month. Vascular densities were determined by computed morphometric analysis of histologic sections. Vascular counts of areas adjacent to the channels in the non- and transmural laser groups did not differ significantly from control groups (arteriolar counts: 0.27 +/- 0.16 and 0.26 +/- 0.16 vs. 0.29 +/- 0.11/mm2, respectively). When bovine bone protein growth factor mixture is added, neovascularization is increased significantly in non- and transmural mixed groups (1.04 +/- 0.79 and 0.69 +/- 0.37/mm2, respectively, p < 0.001 for both comparisons with corresponding laser groups), and there was no significant difference between mixed groups (p = 0.13). In this porcine model, the combination of TMLR with injection of bone protein growth factor mixture induced angiogenesis around the laser channels. Whether the channels did or did not communicate with the endocardial cavity did not influence the neovascular density.

Venous drainage with a single peripheral bicaval cannula for less invasive atrial septal defect repair.

New peripheral venous cannulae have recently been proposed for minimally invasive open cardiac surgery. We present a femoral venous cannula designed to simultaneously drain both superior and inferior vena cavae. Used in adult patients for atrial septal defect repair, the cannula allowed passive blood drainage of 70.6% +/- 11.7% of theoretical cardiac output. Drainage was augmented to 93.4% +/- 8.6% of theoretical cardiac output by means of a centrifugal pump.

The GraftConnector experience. Long-term patency and histological work up in an animal model.

BACKGROUND: A device to perform sutureless end-to-side coronary artery anastomosis has been developed by means of stent technology (GraftConnector). The present study assesses the long-term quality of the GraftConnector anastomosis in a sheep model. METHODS: In 8 adult sheep, 40-55 kg in weight, through left anterior thoracotomy, the right internal mammary artery (RIMA) was prepared and connected to the left anterior descending artery (LAD) by means of GraftConnector, on beating heart, without using any stabilizer. Ticlopidine 250 mg/day for anticoagulation for 4 weeks and Aspirin 100 mg/day for 6 months were given. The animals were sacrificed after 6 months and histological examination of anastomoses was carried out after slicing with the connector in situ for morphological analysis. RESULTS: All animals survived at 6 months. All anastomoses were patent and mean luminal width at histology was 1.8 +/- 0.2 mm; mean myotomia hyperplasia thickness was 0.21 +/- 0.1 mm. CONCLUSIONS: Long-term results demonstrate that OPCABGs performed with GraftConnector had 100% patency rate. The mean anastomotic luminal width corresponds to mean LAD's adult sheep diameter. We may speculate that myotomia hyperplasia occurred as a result of local device oversizing.

Bi-ventricular axial micropump: impact on blood cell integrity.

BACKGROUND AND OBJECTIVE: Off-pump coronary artery bypass grafting has stimulated the development of micro-pumps designed to prevent the hemodynamic instability induced by heart luxation for the exposure of target vessels of the posterior wall. Impella (Aachen, Germany) developed micro-pumps with a miniaturized propeller system for both sides of the heart. The aim of this study was to analyze the impact of both pumps working together on blood cell integrity. MATERIALS AND METHODS: Both right and left-sided micro-pumps were implanted in 5 calves (body weight, 72_4 Kg) during 3 h. Blood samples for hematology and hemolysis parameters were drawn hourly. RESULTS: Both pumps performed well with a flow of 3.6 L +/- 0.3 L during the 3 h of the experiment with stable hemodynamic conditions. Mixed venous oxygen saturation was 63.4 +/- 15.2% at baseline and 63.8 +/- 16.3% at the end of the experiment (P = ns). Red cell count, LDH and free plasma hemoglobin were 6.7 +/- 2.1 x 10(12)/L, 1807 +/- 437 IU/L, and 32 +/- 9 mg/L at baseline vs. 6.1 +/- 2.1 x 10(12)/L, 1871 +/- 410 IU/L, and 52 +/- 9 mg/L at the end of the experiment (P = ns for all comparisons). Platelet count exhibited a non-significant drop (872 +/- 126 vs. 715 +/- 22 x 10(9)/L). CONCLUSIONS: This double pump system based on the Archimed screw principle is hematologically well tolerated under conditions of prolonged cardiac assist.

Alternatives to unfractionated heparin for anticoagulation in cardiopulmonary bypass.

Despite the progress made in the development of cardiopulmonary bypass (CPB) equipment, systemic anticoagulation with unfractionated heparin and post-bypass neutralization with protamine are still used in most perfusion procedures. However, there are a number of situations where unfractionated heparin, protamine or both cannot be used for various reasons. Intolerance of protamine can be addressed with extracorporeal heparin removal devices, perfusion with (no) low systemic heparinization and, to some degree, by perfusion with alternative anticoagulants. Various alternative anticoagulation regimens have been used in cases of intolerance to unfractionated heparin, including extreme hemodilution, low molecular weight heparins, danaparoid, ancrod, r-hirudin, abciximab, tirofiban, argatroban and others. In the presence of heparin-induced thrombocytopenia (HIT) and thrombosis, the use of r-hirudin appears to be an acceptable solution which has been well studied. The main issue with r-hirudin is the difficulty in monitoring its activity during CPB, despite the fact that ecarin coagulation time assessment is now available. A more recent approach is based on selective blockage of platelet aggregation by means of monoclonal antibodies directed to GPIIb/IIIa receptors (abciximab) or the use of a GPIIb/IIIa inhibitor (tirofiban). An 80% blockage of the GPIIb/IIIa receptors and suppression of platelet aggregation to less than 20% allows the giving of unfractionated heparin and running CPB in a standard fashion despite HIT and thrombosis. Likewise, at the end of the procedure, unfractionated heparin is neutralized with protamine as usual and donor platelets are transfused if necessary. GPIIb/IIIa inhibitors are frequently used in interventional cardiology and, therefore, are available in most hospitals.

Reshaping the remodelled left ventricle: a new concept.

OBJECTIVE: Based on the law of Laplace, transventricular tension members were designed to diminish wall stress by changing the left ventricle (LV) globular shape to a bilobular one, thus reducing the ventricular wall radius of curvature. This concept was tested in a model of congestive heart failure. METHODS: Seven calves were used for the study (74.3+/-4.2 kg). Treatment efficacy was assessed with sonomicrometric wall motion analysis coupled with intraventricular pressure measurement. Preload increase was applied stepwise with tension members in released and tightened position. RESULTS: Tightening of the tension members improved systolic function for CVP>10 mmHg (dP/dt: 828+/-122 vs. 895+/-112 mmHg/s, P=0.019, for baseline and 20% stress level reduction respectively; wall thickening: 11.6+/-1.5 vs. 13.3+/-1.7%, P<0.001) and diastolic function (LV end-diastolic pressure: 15.9+/-4.8 vs. 13.6+/-2.7 mmHg, P<0.001, for CVP>10 mmHg; peak rate of wall thinning: -12.2+/-2.2 vs. -14+/-2.3 cm(2)/s, P<0.001 and logistic time constant of isovolumic relaxation: 48.4 +/-10.9 vs. 39.8+/-9.6ms, P<0.001, for CVP>5 mmHg). CONCLUSIONS: This less aggressive LV reduction method significantly improves contractility and relaxation parameters in this model of congestive heart failure.

Are standard human coagulation tests suitable in pigs and calves during extracorporeal circulation?

The thrombogenicity of membrane oxygenators as well as clotting parameters profiles, using standard human clotting tests, was analyzed in calves and pigs during 6 h perfusion. Three calves and 3 pigs were connected to extracorporeal circulation with standard heparinization. Blood samples were taken for coagulation variables throughout perfusion, and oxygenators were examined for clot deposits at the end of the experiment. Two out of 3 oxygenators of the calf group presented clot deposits while none in the pig group did. Baseline coagulation variables of pigs showed values similar to those of humans while neither extrinsic nor intrinsic pathways could be activated in calves with standard human coagulation tests. The calf model, in conclusion, was confirmed to be a difficult model for the testing of extracorporeal circulation device resistance to thrombus formation, which is, however, not reflected by standard human coagulation tests. The pig model is a better model in which both coagulation pathways could be activated with standard human coagulation tests.

Tricuspid valve involvement in combined mitral and aortic valve surgery.

BACKGROUND: Combined mitral and aortic valve disease requiring surgery may involve the tricuspid valve as well. Our treatment policy is conservative especially for tricuspid regurgitation which is operated on when severe only. METHODS: A retrospective study was performed at a tertiary and secondary referral center for cardiovascular disease. Over a 15-year period, 65 consecutive patients underwent aortic and mitral surgery with concomitant tricuspid regurgitation and/or stenosis. Fifty-five/65 (85%) patients were in NYHA class III-IV. Fifty-eight/65 (89%) patients had tricuspid regurgitation secondary to right chamber dilatation and 7/65 (11%) had tricuspid stenosis and/or regurgitation because of previous endocarditis. Twenty-two/65 (34%) tricuspid valves were operated on: 18/22 (82%) de Vega annuloplasty, 2/22 (9%) commissurotomies and 2/22 (9%) prosthetic valves. Mortality and complications were recorded during a mean follow-up of 5.3 yrs (range, 6 months-15.3 yrs). Event-free survivals were determined using the Kaplan-Meier method. RESULTS: Hospital mortality was 6.2% (4/65) and the complication rate was 18.5% (12/65). The freedom from late valve related mortality and morbidity at 5, 10 and 15 years was 86+/-5.5%, 81.9+/-6.8%, and 81.9+/-6.8% respectively. One valve related complication was due to the tricuspid valve. At last follow-up, 87% (47/54) of the survivors were in NYHA class I-II. CONCLUSIONS: With a conservative policy of tricuspid valve intervention, functional results of this patient population are good and long-term valve related morbidity and mortality are mainly related to the mitral and aortic valve procedures.

Intrachannel versus interchannel application of angiogenic factors in transmyocardial laser revascularization.

BACKGROUND AND OBJECTIVE: Theoretically myocardial angiogenesis of laser injury can be further enhanced by the addition of angiogenic growth factors. The influence of the way of administration of these factors on vascular growth around the channels is still unclear. MATERIALS AND METHODS: 18 pigs (mean weight 72 +/- 5.2 kg) were randomized to either triads of transmyocardial laser revascularization (TMLR) channels (group 1, n = 6) or isolated channels (group 2, n = 6), or a control group (n = 6). The animals had injections of bovine bone derived growth factor mixture either in the center of the triads in group 1 or within the channels themselves in group 2. Animals were sacrificed one month later for histological analysis. RESULTS: The vascular densities of myocardial areas within the triads of group 1 and around the channels in group 2 were significantly larger than in the control group: 15.2 +/- 3.7/mm2 and 14.2 +/- 3.5/mm2 respectively vs 5.3 +/- 1.6/mm2 (p < 0.001 for both differences). Differences of densities between group 1 and 2 were not statistically significant (p = 0.6). CONCLUSIONS: In this porcine model, the addition of a bovine bone derived growth factor mixture to TMLR significantly stimulates angiogenesis in the areas adjacent to the channels. The place of injection does not influence the angiogenesis intensity.

Does laser injury induce a different neovascularisation pattern from mechanical or ischaemic injuries?

AIM: To analyse the arteriolar pattern of laser induced channels and their surroundings compared with mechanical and ischaemic injury. METHODS: 24 pigs were randomised to a myocardial infarction group, a transmyocardial laser revascularisation group, a needle group, or a control group. In the laser revascularisation and needle groups, five channels were created either with a 1.75 mm probe holmium-YAG laser or a Tru-cut needle of the same size. Animals were killed 28 days later. Morphometric analysis of vascular density was expressed as the mean (SD) number of arteriolar structures/cm(2). RESULTS: Laser and needle channels were completely invaded by granulation tissue. Their surface areas did not differ significantly: 2.28 (0.7) mm(2) and 2.38 (1.1) mm(2), respectively (p = 0.82). Within both types of channel, arteriolar density was significantly increased in comparison with the myocardial infarction scar: 197 (52)/cm(2) and 190 (64)/cm(2), respectively (p = 0.8) versus 56 (20)/cm(2) (p < 0.001 for both comparisons). The area of 1 mm width immediately adjacent to the laser and needle channels showed a density of 25 (16)/cm(2) and 23 (18)/cm(2), respectively, which is similar to that of normal tissue (28 (10)/cm(2); p = 0.6 and p = 0.4, respectively). The mean arteriolar diameter was similar throughout all the regions analysed. CONCLUSIONS: Both laser and needle channels produce a similar increase in arteriolar structures, which is limited to the lesion itself. This suggests that laser injury is not more potent as an angiogenic stimulator than mechanical injury, which in turn is superior to infarction.

Atrial, ventricular, or both cannulation sites to optimize left ventricular assistance?

The efficiency of left ventricular assist devices (LVADs) depends on the capacity of the inflow cannula to drain blood into the pump. Left atrial (LA) and left ventricular (LV) sites were compared in an animal model mimicking different hemodynamic conditions. Three calves (56.3+/-5.0 kg) were equipped with a Thoratec LVAD. A regular cardiopulmonary bypass (CPB) circuit was used as a right ventricular assist device (RVAD) (jugular vein/pulmonary artery), and preload conditions were adjusted by storage (or perfusion) of blood into (or from) the venous reservoir. LA and LV drainage, tested separately or simultaneously, was measured by its effect on the LVAD's performance. The LVAD was used alone on a beating heart or together with the RVAD (biVAD) on a beating and on a fibrillating heart. Increasing the central venous pressure (CVP) highlighted the differences between the LA and LV cannulation sites when the LVAD was tested either alone or together with the RVAD (biVAD) on a beating heart. Drainage through the LA or the LV was similar when CVP was set at 8 mm Hg, and increasing CVP to 14 mm Hg allowed for better drainage through the LV cannula. In contrast, after induction of fibrillation to mimic extreme heart failure, the drainage was better through the LA cannula. Using both LA and LV cannulae simultaneously did not improve the LVAD output in any of the conditions tested. LV cannulation provides better blood drainage when used on a normal beating heart and, therefore, allows for increased LVAD performance. However, in severe heart failure, blood drainage through the LV cannula decreases and the LA cannulation site is superior.

Active cooling during open repair of thoraco-abdominal aortic aneurysms improves outcome.

OBJECTIVE: Evaluate impact of active cooling with partial cardiopulmonary bypass (CPB) and low systemic heparinization during open repair of thoracoabdoninal aortic aneurysms. METHODS: Prospective analysis of 100 consecutive patients undergoing surgical repair of thoracoabdominal aortic aneurysms. Partial CPB and normothermic (36 degrees C) or hypothermic (29 degrees C) perfusion was selected in accordance to the surgeons preference. In the hypothermic group, aortic cross clamp was applied when the target temperature of the venous blood was achieved and rewarming was started after declamping. RESULTS: 52/100 patients (62.2+/-10.9 years) received normothermic and 48/100 patients hypothermic perfusion (63.8+/-10.6 years: NS). Emergent procedures accounted for 18/52 (35%) with normothermia vs. 21/48 (44%: NS) with hypothermia. The number of aortic segments (eight = maximum including arch and bifurcation) replaced was 3.9+/-1.5 with normothermia vs. 4.1+/-1.5 with hypothermia (NS); Crawford type II aneurysms accounted for 21/52 patients (40%) for normothermia vs. 20/48 (42%:NS) for hypothermia. Total clamp time was 38+/-21 min with normothermia vs. 47+/-28 min with hypothermia (P=0.05). Pump time was 55+/-28 min with normothermia vs. 84+/-34 min with hypothermia (P=0.001). Mortality at 30 days was 8/52 patients (15%) with normothermia vs. 2/48 (4%) with hypothermia (P=0.06; odds ratio = 4.1). Parapareses/plegias occurred in 4/52 patients (8%) with normothermia vs. 4/48 (8%) with hypothermia (NS). Revisions for bleeding were required in 4/52 patients (8%) with normothermia vs. 2/48 patients (4%) with hypothermia (P=0.38). Revisions for distal vascular problems were necessary in 5/52 patients (10%) with normothermia vs. 2/48 (4%) with hypothermia (P=0.25). Freedom from death, paraplegia, and surgical revision was 89.9% with normothermia vs. 94.8% with hypothermia (P=0.04; odds ratio 2.0). CONCLUSIONS: Active cooling during repair of thoracoabdominal aortic aneurysms allows for longer cross-clamp times, more complex repairs and improves outcome.

Smart suction device for less blood trauma: a comparison with Cell Saver.

OBJECTIVE: The major source of hemolysis during cardiopulmonary bypass remains the cardiotomy suction and is primarily due to the interaction between air and blood. The Smart suction system involves an automatically controlled aspiration designed to avoid the mixture of blood with air. This study was set-up to compare this recently designed suction system to a Cell Saver system in order to investigate their effects on blood elements during prolonged intrathoracic aspiration. METHODS: In a calf model (n=10; mean weight, 69.3+/-4.5 kg), a standardized hole was created in the right atrium allowing a blood loss of 100 ml/min, with a suction cannula placed into the chest cavity into a fixed position during 6 h. The blood was continuously aspirated either with the Smart suction system (five animals) or the Cell Saver system (five animals). Blood samples were taken hourly for blood cell counts and biochemistry. RESULTS: In the Smart suction group, red cell count, plasma protein and free hemoglobin levels remained stable, while platelet count exhibited a significant drop from the fifth hour onwards (prebypass: 683+/-201*10(9)/l, 5 h: 280+/-142*10(9)/l, P=0.046). In the Cell Saver group, there was a significant drop of the red cell count from the third hour onwards (prebypass: 8.6+/-0.9*10(12)/l, 6 h: 6.3+/-0.4*10(12)/l, P=0.02), of the platelet count from the first hour onwards (prebypass: 630+/-97*10(9)/l, 1 h: 224+/-75*10(9)/l, P<0.01), and of the plasma protein level from the first hour onwards (prebypass: 61.7+/-0.6 g/l, 1 h: 29.3+/-9.1 g/l, P<0.01). CONCLUSIONS: In this experimental set-up, the Smart suction system avoids damage to red cells and affects platelet count less than the Cell Saver system which induces important blood cell destruction, as any suction device mixing air and blood, as well as severe hypoproteinemia with its metabolic, clotting and hemodynamic consequences.