Preschool children born moderately preterm have increased waist circumference at two years of age despite low body mass index.

AIM: To investigate the development of waist circumference (WC) in preschool children born preterm compared with a population-based reference. BACKGROUND: Children born preterm are reported to be insulin resistant, despite being lean during early childhood. We hypothesize that the mechanism is through increased visceral adiposity. METHODS: Data from 4446 preschool children (2169 girls/2277 boys) born in 2001-2006 from a population-based study were compared with longitudinal measurements of body mass index (BMI) and WC from a cohort of 152 children (64 girls/88 boys) born moderately preterm in 2002-2004 (gestational age, 32-37 weeks). RESULTS: In the preterm children, the mean WC was 2.8 cm larger compared with the reference group (p < 0.001) at 2 years of age but not at 5 years of age. There was no significant difference in the mean BMI at 2 years of age. The preterm group was significantly leaner at 5 years of age, with a mean BMI of 15.13 compared with 15.98 in the reference group (p < 0.001). CONCLUSION: Children born moderately preterm present as lean during early childhood but have an increased waist circumference in infancy, pointing towards a change in fat distribution with more abdominal fat. This may have implications for their metabolic status.

Navigated ultrasound in laparoscopic surgery.

Laparoscopic surgery is performed through small incisions that limit free sight and possibility to palpate organs. Although endoscopes provide an overview of organs inside the body, information beyond the surface of the organs is missing. Ultrasound can provide real-time essential information of inside organs, which is valuable for increased safety and accuracy in guidance of procedures. We have tested the use of 2D and 3D ultrasound combined with 3D CT data in a prototype navigation system. In our laboratory, micro-positioning sensors were integrated into a flexible intraoperative ultrasound probe, making it possible to measure the position and orientation of the real-time 2D ultrasound image as well as to perform freehand 3D ultrasound acquisitions. Furthermore, we also present a setup with the probe optically tracked from the shaft with the flexible part locked in one position. We evaluated the accuracy of the 3D laparoscopic ultrasound solution and obtained average values ranging from 1.6% to 3.6% volume deviation from the phantom specifications. Furthermore, we investigated the use of an electromagnetic tracking in the operating room. The results showed that the operating room setup disturbs the electromagnetic tracking signal by increasing the root mean square (RMS) distance error from 0.3 mm to 2.3 mm in the center of the measurement volume, but the surgical instruments and the ultrasound probe added no further inaccuracies. Tracked surgical tools, such as endoscopes, pointers, and probes, allowed surgeons to interactively control the display of both registered preoperative medical images, as well as intraoperatively acquired 3D ultrasound data, and have potential to increase the safety of guidance of surgical procedures.

Navigation in laparoscopy--prototype research platform for improved image-guided surgery.

The manipulation of the surgical field in laparoscopic surgery, through small incisions with rigid instruments, reduces free sight, dexterity, and tactile feedback. To help overcome some of these drawbacks, we present a prototype research and development platform, CustusX, for navigation in minimally invasive therapy. The system can also be used for planning and follow-up studies. With this platform we can import and display a range of medical images, also real-time data such as ultrasound and X-ray, during surgery. Tracked surgical tools, such as pointers, video laparoscopes, graspers, and various probes, allow surgeons to interactively control the display of medical images during the procedure. This paper introduces navigation technologies and methods for laparoscopic therapy, and presents our software and hardware research platform. Furthermore, we illustrate the use of the system with examples from two pilots performed during laparoscopic therapy. We also present new developments that are currently being integrated into the system for future use in the operating room. Our initial results from pilot studies using this technology with preoperative images and guidance in the retroperitoneum during laparoscopy are promising. Finally, we shortly describe an ongoing multicenter study using this surgical navigation system platform.

Navigated retrograde endoscopic myotomy (REM) for the treatment of therapy-resistant achalasia.

BACKGROUND: In achalasia, muscle spasm may involve the proximal esophagus. When the muscle spasm is located in the proximal esophagus, conventional per oral endoscopic myotomy (POEM) may not be sufficient to relieve symptoms. In this paper, we describe retrograde endoscopic myotomy (REM) as a novel approach to perform myotomy of the proximal esophagus, with the application of a navigation tool for anatomical guidance during REM. We aim to evaluate the feasibility and safety of REM and usefulness of the navigation during REM. METHOD: A 42-year-old male with type III achalasia who was treated with laparoscopic myotomy with fundoplication, multiple pneumatic balloon dilations, Botox injections and anterior POEM of the middle and distal esophagus without symptomatic effect. Repeated high-resolution- manometry (HRM) revealed occluding contractions of high amplitude around and above the aortic arch. A probe-based real-time electromagnetic navigation platform was used to facilitate real-time anatomical orientation and to evaluate myotomy position and length during REM. RESULTS: The navigation system aided in identifying the major structures of the mediastinum, and position and length of the myotomy. Twelve weeks after REM, the Eckardt score fell from seven at baseline seven to two. We also observed improvement with reduction of the pressure at the level of previous spasms in the proximal esophagus from 124 mmHg to 8 mmHg on HRM. CONCLUSION: REM makes the proximal esophagus accessible for endoscopic myotomy. Potential indication for REM is motility disorders in the proximal esophagus and therapy failure after POEM.

Side-branched AAA stent graft insertion using navigation technology: a phantom study.

OBJECTIVE: To evaluate the feasibility of a side-branched stent graft inserted in an artificial abdominal aortic aneurysm (AAA), using navigation technology, and to compare procedure duration and dose of radiation with control trials. METHODS: A custom-made stent graft was inserted into an artificial AAA using navigation technology in combination with fluoroscopy. The navigation technology was based on three-dimensional visualization of computed tomography data and electromagnetic tracking of microposition sensors. The stent graft had integrated position sensors in side branch and introducer and was guided into proper position with the aid of three-dimensional images. Control trials were performed with fluoroscopy alone. RESULTS: It was feasible to insert a side-branched stent graft using three-dimensional navigation technology. The navigation-guided trials had a significantly lower X-ray load (p < 0.001), but showed no difference in the duration of the procedures (p = 0.34) as compared with controls. CONCLUSIONS: Inserting a side-branched stent graft in an artificial AAA using navigation technology is feasible. Side-branched stent grafts and navigation systems may become useful in the endovascular treatment of complicated aortic aneurysms.

Image-guided laparoscopic surgery. Review and current status.

The main drawback with laparoscopic surgery is that the surgeon is unable to palpate vessels, tumours and organs during surgery. Further-more, the laparoscope only provides a surface view of organs. There is a need for more advanced visualizations techniques that can enhance the display presented to the surgeon so that important information below the surface of the organs is included when planning the procedure as well as for guidance and control during treatment. In this paper, we present a review of the literature and the state of art within image-guided laparoscopic surgery. We describe our own experience using a prototype navigation system for advanced visualizations and guidance during laparoscopic procedures in the retroperitoneum. Furthermore, we show sample images from the Future Operating Room for laparoscopic surgery in Trondheim, where this technology is being further developed and tested in clinical studies. Our system is based on three-dimensional navigation technology, i.e. preoperatively acquired magnetic resonance or computed tomography data used in combination with tracked instruments, allowing the surgeon to interactively control the display of images prior to and during surgery with normal use of the instruments. In summary, we believe that abdominal image navigation using tracked instruments and advanced visualizations has a large potential for improving future laparoscopic surgery, especially in cases where vessels and anatomical relations beyond surfaces is difficult to identify using only a laparoscope. The technology helps the surgeon to better understand the anatomy and locate blood vessels. Accordingly, we believe that this new technology could increase safety and make it easier for the surgeon to perform successful laparoscopic surgery.

Hemodynamic evaluation by Doppler echocardiography of small (less than or equal to 21 mm) prostheses and bioprostheses in the aortic valve position.

To assess resting hemodynamics of an unselected group of patients with prostheses or bioprostheses sized less than or equal to 21 mm implanted into the aortic valve position during a 7-year period, 46 of 50 eligible patients were examined by Doppler echocardiography. The valves were Carpentier-Edwards (CE) supraannular 21 mm (n = 8), Medtronic-Hall (MH) 20 mm (n = 8) and 21 mm (n = 21), and the rest (n = 9) were other valves with only 1 to 3 patients in each group. Gradients, valve areas and dimensionless obstruction indexes (ratio of subvalvular/valvular velocities and velocity time integrals) were compared. By analysis of variance, gradients did not differ significantly between the CE supraannular 21 mm, the MH 20 and 21 mm prostheses (peak/mean 25 +/- 8/14 +/- 5, 31 +/- 13/16 +/- 6 and 25 +/- 10/13 +/- 5 mm Hg; p = not significant). Only 2 patients had a mean gradient greater than 25 mm Hg. The valve area was slightly larger for the MH 21 mm group compared with the CE supraannular 21 mm group (1.34 +/- 0.15 vs 1.16 +/- 0.14 cm2, p less than 0.05). The dimensionless obstruction indexes did not differ (CE supraannular 21 mm 0.36 +/- 0.07/0.40 +/- 0.07 (velocities/velocity time integrals), MH 20 mm 0.40 +/- 0.12/0.47 +/- 0.12, MH 21 mm 0.38 +/- 0.05/0.44 +/- 0.06; p = not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of two heparin-coated extracorporeal circuits with reduced systemic anticoagulation in routine coronary artery bypass operations.

OBJECTIVES: The use of heparin-coated circuits for cardiopulmonary bypass attenuates the postperfusion inflammatory response. Postoperative bleeding and the need for allogeneic blood transfusions are reduced, particularly in combination with lowered systemic anticoagulation. The two most commonly used heparin-coated systems are the Carmeda BioActive Surface (Medtronic Inc, Minneapolis, Minn) and the Duraflo II coating (Baxter Healthcare Corp, Bentley Laboratories Division, Irvine, Calif). The 2 surfaces are technically unequal, and previous experimental studies have demonstrated disparities in effects on the immune system and the blood cells. However, no larger comparative studies of relevant clinical end points have thus far been reported. METHODS: Over a 24-month period, all patients undergoing coronary artery bypass were prospectively randomized to one of the two heparin-coated circuits. Altogether, 1336 consecutive patients were included. The heparin dose was reduced in all cases, with an activated coagulation time of more than 250 seconds. Clinical data were consecutively collected and stored on a computer for comparative analyses. RESULTS: There were no statistically significant differences in any demographic or operative parameters. The Duraflo II patients required less heparin to keep the target-activated clotting time, confirming the previous finding of some leakage of heparin from the surface to the circulation. Otherwise, there were no significant differences in time for ventilatory support (Duraflo II, 1.7 +/- 1.3 hours; Carmeda BioActive Surface, 1.6 +/- 1.0 hours; P =.37), amount of postoperative mediastinal drainage (Duraflo II, 665 +/- 257 mL; Carmeda BioActive Surface, 688 +/- 243 mL; P =.07), need for allogeneic blood-plasma transfusions (Duraflo II, 4.2% of the patients; Carmeda BioActive Surface, 4.4% of the patients; P =.93), or hemoglobin concentration at hospital discharge (Duraflo II, 120 +/- 13 g/L; Carmeda BioActive Surface, 119 +/- 13 g/L; P =.08). The effects on renal function and platelets were similar, as were the incidences of perioperative myocardial infarction (Duraflo II, 1.5%; Carmeda BioActive Surface, 1.5%; P =.96), stroke (Duraflo II, 1.3%; Carmeda BioActive Surface, 1.2%; P =.47), and hospital mortality (Duraflo II, 1 [0.14%] patient; Carmeda BioActive Surface, 3 [0.45%] patients; P =.31). CONCLUSIONS: Despite differences in technology, complexity, and effects on biologic markers, no clinical differences were observed between the Carmeda BioActive Surface system and the Duraflo II coating after coronary artery bypass operations. The overall clinical results were favorable in both groups, confirming the safety and feasibility of routine use of heparin-coated circuits in combination with reduced systemic anticoagulation.

Autotransfusion in coronary artery bypass grafting: disparity in laboratory tests and clinical performance.

OBJECTIVE: Autotransfusion during and after cardiac surgery is widely performed, but its effects on coagulation, fibrinolysis, and inflammatory response have not been known in detail. METHODS: Hemostatic and inflammatory markers were extensively studied in 40 coronary artery bypass patients undergoing a consistent intraoperative and postoperative autotransfusion protocol. An identical autotransfusion protocol was applied to 4916 consecutive coronary patients and the overall clinical results were evaluated in this large patient population. RESULTS: The autologous blood pooled before bypass remained nearly inactivated after storage. A slight elevation of thrombin-antithrombin complex and prothrombin fragment 1.2, as well as plasmin/alpha(2)-antiplasmin complex was found in the content of the extracorporeal circuit after surgery, indicating thrombin formation and fibrinolytic activity. Also some increase of beta-thromboglobulin was present. In the mediastinal shed blood, complete coagulation, as evidenced by the absence of fibrinogen, had taken place and all parameters described above were extremely elevated. However, no thrombin activity was detected. As for the inflammatory response, moderately increased levels of complement activation products, terminal complement complex, and interleukin-6 traced in the extracorporeal circuit reached very high levels in mediastinal shed blood. Autotransfusion of the residual extracorporeal circuit blood and the mediastinal drainage was followed by elevation of most of these markers in circulating plasma. On the other hand, no correlating harmful effects were recorded in the study patients or in the consecutive 4916 patients. Coagulation disturbances were rare and allogeneic transfusions were required in fewer than 4% of all patients. CONCLUSIONS: The hemostatic and immunologic systems were moderately activated in the autologous blood remaining in the extracorporeal circuit, whereas the mediastinal shed blood was highly activated in all aspects. However, autotransfusion had no correlating clinical side-effects and the subsequent exposure to allogeneic blood products was minimal.

Complement and granulocyte activation in two different types of heparinized extracorporeal circuits.

Complement and granulocyte activation were studied in cardiopulmonary bypass circuits completely coated with either end-attached covalent-bonded heparin, the Carmeda BioActive Surface, or with the Duraflo II bonded heparin, in combination with reduced systemic heparinization (activated clotting time > 250 seconds). The control groups were perfused with uncoated circuits and full heparin dose (activated clotting time > 480 seconds). Altogether 67 patients undergoing elective first-time myocardial revascularization were investigated, having extracorporeal perfusion with a Duraflo II coated circuit (n = 17), an identical but uncoated circuit (n = 17), a Carmeda coated circuit (n = 17), or an equivalent uncoated circuit (n = 16). During cardiopulmonary bypass, the C3 activation products C3b, iC3b, and C3c (C3bc) and the terminal SC5b-9 complemented complex increased markedly in all four groups compared with baseline, but significantly less in the two coated groups than in their control groups. Additionally, a significantly lower concentration of C3bc was observed in the Carmeda coated group, with maximal increase of median 28 AU/ml compared with 50 AU/ml in the Duraflo II coated group (p = 0.003). Similarly, in the Carmeda coated group, the maximal increase of terminal complement complex was considerably lower (0.8 AU/ml) than the levels recognized in the Duraflo II coated group (2.4 AU/ml) (p < 0.001). The release of the granulocyte activation myeloperoxidase and lactoferrin increased from the beginning of the operation, with peak levels at the end of bypass. A significant reduction of lactoferrin release was recognized when comparing the coated groups with the control groups. The difference between the two coated groups (Carmeda 228 micrograms/L; Duraflo II 332 micrograms/L; p = 0.05) was marginally significant. For myeloperoxidase, no significant differences were observed between the coated and uncoated groups. In conclusion, both types of heparin-coated circuits reduced complement activation and release of lactoferrin, but the Carmeda circuit proved to be more effective than the Duraflo II equipment.

Rapid recovery protocol applied to 5,658 consecutive "on-pump" coronary bypass patients.

BACKGROUND: Increasing hospital costs, restricted resources, and new surgical strategies have stimulated effectiveness of all routines in cardiac surgery. Over a 10-year period, 5,658 consecutive patients undergoing coronary artery bypass grafting followed a protocol aiming at short postoperative intubation times and rapid physical rehabilitation. METHODS: The patients were prepared for rapid recovery, emphasizing (1) preoperative education and respiratory training, (2) low-dose fentanyl anesthesia, (3) limited ischemic times and pump times, (4) mild hypothermia and rewarming to a rectal temperature of 36 degrees C, (5) restricted use of extended monitoring, (6) autologous blood salvage to avoid allogeneic blood transfusions, and (7) active physical training from postoperative day 1. All in-hospital data relevant to these steps were prospectively stored in a database. RESULTS: The median extubation time after arrival in the intensive care unit was 1.5 hours (0 to 320 hours). More than 99% of the patients were extubated within 5 hours. Sixty-two patients (1.1%) were reintubated and ventilated for a median of 24 hours (1 to 430 hours), mostly due to resternotomy for bleeding or cardiopulmonary decompensation. In total, 5,594 patients (98.9%) were able to sit in a chair the first postoperative day. Within the fourth postoperative day, 82.5% were able to move freely in the hospital area and were in fact physically fit for hospital discharge. Allogeneic blood products were given to 3.9% of the patients. Twenty-three patients (0.41%) died in-hospital. CONCLUSIONS: With the application of a protocol for rapid physical recovery in patients undergoing "on-pump" coronary artery bypass grafting, extubation within 1 to 2 hours was safe and feasible in most patients. After 5 hours, 99.3% of the patients were extubated, with a reintubation rate of 1.1%. More than 80% of the patients were fully physically mobile within 4 days after the operation.

Facing the era of minimally invasive coronary grafting: current results of conventional bypass grafting for single-vessel disease.

BACKGROUND: The concepts of minimally invasive coronary artery bypass grafting have gained increasing attention and interest from cardiac surgeons. Operations through small incisions are mostly applied to patients with less extensive coronary disease, mostly single-vessel disease. The aim of this study was to identify a baseline level of conventional coronary bypass grafting for this group of patients, particularly with regard to surgical complications and immediate results. METHODS: Of 3,637 consecutive patients undergoing coronary artery bypass grafting during the period 1989 to 1995, 99 patients (2.7%) were identified to have single-vessel disease. The preoperative and hospital data of this subset of patients were analyzed. RESULTS: The left internal mammary artery was grafted in 96% of the patients, either as single graft to the left anterior descending artery or sequentially to the left anterior descending artery and a diagonal branch. Additional vein grafts were placed in 36 patients, and the mean number of distal anastomoses was 1.6 +/- 0.6. Mean ischemic time and cardiopulmonary bypass time were 15.3 +/- 9.6 minutes and 29.0 +/- 12.5 minutes, respectively. The patients were weaned from the ventilator 1.5 +/- 0.8 hours postoperatively, and all patients were out of bed the morning after the operation. No patients required homologous blood or plasma transfusions. The morbidity rate was low, and all patients survived. CONCLUSIONS: For this highly selected group of patients, coronary artery bypass grafting based on median sternotomy, cardiopulmonary bypass, and cardioplegic arrest carries a very high rate of immediate success. Such data may be useful as a baseline when considering the costs and benefits of new surgical procedures.

Heparinized cardiopulmonary bypass and full heparin dose marginally improve clinical performance.

BACKGROUND: The use of completely heparin coated cardiopulmonary bypass circuits in combination with a reduced systemic heparin dose has previously been shown to reduce postoperative bleeding after cardiac operations. However, it has remained unknown whether this effect was related to the improved biocompatibility of the heparin-treated surfaces per se or to the reduced exposure to circulating heparin. Therefore we investigated patients undergoing heparin-coated extracorporeal circulation and full systemic heparinization. METHODS: Two hundred seventeen patients having first-time myocardial revascularization were prospectively randomized either to a group in which a completely ("tip-to-tip") heparin-coated circuit (Duraflo II) was used for perfusion (n = 107) or to a control group (n = 110) in which an uncoated, but otherwise identical, circuit was used. Full systemic heparinization was induced in both groups (activated clotting time, > 480 seconds). The postoperative blood loss, requirements for homologous blood transfusions, clinical performance, and complications were recorded. RESULTS: The amount of postoperative mediastinal drainage was nearly identical in the two groups. The mean 18-hour drainage was 694 +/- 313 mL in the heparin-coated group and 679 +/- 269 mL in the control group (p = not significant). Three patients in the heparin-coated group and 6 patients in the control group received homologous red blood cell transfusions (p = not significant). The incidence of postoperative atrial fibrillation was significantly lower in the heparin-coated group (21.8%) than in the control group (43.1%) (p = 0.002). Otherwise, there were no significant differences in the extubation times, the incidence of perioperative myocardial infarction, the creatinine concentration, the incidence of neurologic dysfunction, the progress in physical rehabilitation, or the hemoglobin concentration at discharge. CONCLUSIONS: The use of completely heparin coated cardiopulmonary bypass circuits and full systemic heparinization in patients undergoing coronary artery bypass procedures did not reduce postoperative bleeding or change clinical performance, except for a significant decrease in the incidence of postoperative atrial fibrillation.

Conversion of postischemic ventricular fibrillation with intraaortic infusion of potassium chloride.

BACKGROUND: Ventricular fibrillation after declamping of the aorta after cardioplegic arrest is commonly managed by direct-current countershock. However, in coronary artery bypass grafting, placement of the electrodes can cause mechanical damage to the grafts and anastomoses, and the surgical procedure must be interrupted. As an alternative, intraaortic infusion of potassium chloride through the arterial line from the heart-lung machine was investigated. METHODS: In a series of 100 patients with postischemic ventricular fibrillation (group P), 20 mmol of potassium chloride (plus 10 mmol later if necessary) was added to the oxygenator reservoir and perfused through the arterial line into the proximal aorta. The results were compared with those in a matched control group of 100 patients primarily treated with direct-current countershock (group DC). RESULTS: In group P, the ventricular fibrillation was effectively converted to a supraventricular rhythm in 82% of the patients. The remaining 18 patients required significantly (p < 0.005) fewer electric shocks than the patients in group DC. Serum K+ levels were slightly elevated for a short period after the potassium chloride infusion. Otherwise there were no significant differences in regard to incidence of heart block, temporary epicardial pacing, myocardial infarction, or atrial fibrillation between the two groups. CONCLUSIONS: Conversion of postischemic ventricular fibrillation with potassium chloride administered through the arterial line from the heart-lung machine is an effective, gentle, and convenient method. No side effects were noted.

Completely heparinized cardiopulmonary bypass and reduced systemic heparin: clinical and hemostatic effects.

BACKGROUND: When heparinized circuits are used for cardiopulmonary bypass, the amounts of heparin and protamine administered systemically can be reduced. However, it is not entirely known what effects this reduction in systemic anticoagulation has on clinical performance and on the coagulation and fibrinolytic systems. METHODS: Two hundred three patients undergoing first-time elective myocardial revascularization were prospectively randomized either to a group in which a completely heparin-coated circuit was used for perfusion (group H; n = 101 patients) and in which a reduced heparin dose was given (activated clotting time, > 250 seconds) or to a control group (group C; n = 102 patients) in which an uncoated, but otherwise identical, circuit was used and in which full systemic heparinization was induced (activated clotting time, > 480 seconds). Indicators of thrombin generation, platelet activation, and fibrinolytic activity were studied in a subset of 34 patients. RESULTS: The total amount of postoperative mediastinal drainage was significantly reduced in group H (median, 575 mL) compared with that in group C (median, 635 mL; p = 0.002). Two patients in group C but none in group H received homologous red blood cell transfusions (p = not significant). The loss of hemoglobin in group H was a median of 21 g/L, and this was significantly lower than the 25 g/L noted in the control group (p = 0.006). During cardiopulmonary bypass, the plasma levels of thrombin-antithrombin complex and prothrombin fragment 1.2 increased in both groups. At the end of cardiopulmonary bypass the plasma levels of these markers of thrombin formation were significantly higher in group H, although the increase was modest compared with the major increase observed 2 hours after operation in both groups. There were no significant intergroup differences in the platelet counts, the concentration of beta-thromboglobulin, or the plasma levels of fibrinogen and D-dimer. No differences in perioperative morbidity, the postoperative kidney function, or the intubation time were observed, and there were no hospital deaths. CONCLUSIONS: The combination of complete heparin-coated cardiopulmonary bypass circuits and low systemic heparinization is safe for patients undergoing elective coronary artery bypass procedures and reduces the perioperative blood loss. There was no evidence of increased thrombogenicity, fibrinolytic activity, or consumption of coagulation factors. No clinical or technical side effects were observed.

High and low heparin dose with heparin-coated cardiopulmonary bypass: activation of complement and granulocytes.

BACKGROUND: Cardiopulmonary bypass with heparin-coated circuits allows reduced amounts of systemic heparin. Heparin inhibits activation of the complement cascade experimentally, but the effects of different levels of systemic heparin on activation of complement and granulocytes in patients have remained unknown. METHODS: Fifty-two patients undergoing coronary artery bypass procedures were studied. Cardiopulmonary bypass circuits completely coated with surface-bound heparin were used for one group given low-dose heparin (n = 17) (activated clotting time > 250 seconds), and was compared with a second group having normal high-dose heparin (activated clotting time > 480 seconds) (n = 18). A third control group was perfused with ordinary uncoated circuits and a full heparin dose (n = 17). RESULTS: During cardiopulmonary bypass, the C3 activation products C3b, iC3b, and C3c increased markedly in all three groups compared with baseline, but significantly less in the two heparin-coated groups (high dose, median maximal increase 58 arbitrary units (AU)/mL; low dose, 48 AU/mL) compared with the uncoated control group (74 AU/mL) (p < 0.01). The difference between the two coated groups was not significant. Similarly, the maximal increase in terminal SC5b-9 complement complex was considerably lower in the heparin-coated groups (high dose, 2.5 AU/mL; low dose, 2.6 AU/mL) compared with the level observed in the uncoated control group (5.3 AU/mL) (p < 0.01). The release of the granulocyte activation enzymes myeloperoxidase and lactoferrin increased from the beginning of the operation, with peak levels at the end of cardiopulmonary bypass (p < 0.01). The concentration of lactoferrin was significantly (p < 0.01) reduced in the low heparin dose group compared with the two other groups receiving normal high heparin doses, indicating that circulating heparin is an important granulocyte agonist, acting independently of the presence or absence of heparin-coated surfaces. Also for myeloperoxidase a higher level was observed in the high heparin dose group. CONCLUSIONS: Complement activation was significantly reduced in both heparin-coated groups and was independent of the level of systemic heparinization, whereas granulocyte activation was reduced only in patients who received low doses of systemically administered heparin. The results indicate that a moderate reduction of the systemic heparin dose may be an advantage with regard to improved biocompatibility when using heparin-coated cardiopulmonary bypass circuits.

Investigation into the origin of the antigens of Mycoplasma arthritidis cross-reacting with host tissue antigens.

The electrophoretical separations of Mycoplasma arthritidis and the serum used in the cultivation medium show a high number of protein bands with identical molecular weights. Proteins with molecular weights of 84, 72 and 52 kDa also appeared to be identical with proteins of Mycoplasma arthritidis in their antigenic properties as demonstrated by Western blotting with rat-anti-Mycoplasma arthritidis serum. The autoradiography of electrophoretically separated Mycoplasma arthritidis cells metabolically labeled with 35S-methionine and 35S-cysteine revealed that the proteins of Mycoplasma arthiritidis identical in molecular weight and antigenic structure with serum proteins are synthesized by Mycoplasma arthritidis, and represent true translation products.

3D ultrasound-based navigation for radiofrequency thermal ablation in the treatment of liver malignancies.

BACKGROUND: The aim of the study was to compare three methods for ultrasound-based guidance of a radiofrequency probe into liver tumors in a model setup. METHODS: The liver model tumors were placed inside excised calf livers, and the radiofrequency probe was guided into the center using either a new 3D navigation method or two conventional 2D methods-freehand scanning and a method based on a biopsy guide. We performed 54 experiments, measuring the physical distance (all methods) and image distance (3D method only) from the tip of the probe to the center of the tumors. RESULTS: Based on the physical measurements alone, the biopsy-based guiding performed better than both the 2D freehand and the 3D navigation method. However, the 3D image measurements showed that the tip of the probe was better positioned in the center of the model tumors for the 3D navigation method as compared to the physical measurement results for the 2D methods. CONCLUSION: Although it was easier to position the radiofrequency probe accurately using the 3D image display technique, movement of the model tumor during 3D navigation is a challenge.

Laparoscopic navigation pointer for three-dimensional image-guided surgery.

BACKGROUND: The main drawback with the laparoscopic approach is that the surgeon is unable to palpate vessels, tumors, and organs during surgery. Furthermore, the laparoscope provides only surface view of organs. There is a need for more advanced visualizations that can enhance the view to include information below the surface of the organs for planning of the procedure and for control and guidance during treatment. METHODS: We propose three-dimensional (3D) navigation technology based on preoperatively acquired magnetic resonance or computed tomography data used in combination with a laparoscopic navigation pointer (LNP). The LNP has an attached position tracker that allows the surgeon to control the display of images interactively before and during surgery. This study evaluated the patient registration accuracy, the feasibility of image-based navigation and, qualitatively, the navigation precision in the retroperitoneum during laparoscopic surgery. RESULTS: This technology was used during the treatment of six patients (involving adrenalectomies and a neuroma protruding into the pelvis). An average patient registration accuracy of 6.90 mm was achieved. The precision during navigation in the retroperitoneum was, in some cases, better than the patient registration accuracy suggested. The technology helped the surgeons to understand better the anatomy and to locate blood vessels. CONCLUSIONS: In the reported cases, the LNP was a useful tool for image guidance in laparoscopic surgery, both for planning the surgical approach in detail and for guidance. The authors believe that adominal 3D image guidance using an LNP has a large potential for improving laparoscopic surgery, especially when vessels and anatomic relations may be difficult to identify using only a laparoscope. Accordingly, they believe this new technology could increase safety and make it easier for the surgeon to perform successful laparoscopic surgery.

Consistent non-pharmacologic blood conservation in primary and reoperative coronary artery bypass grafting.

Because much interest has been focused on blood conservation using different drugs and complicated blood cell processing devices, we analyzed our results with the use of a non-pharmacologic, simple and inexpensive program for blood salvage in 2326 patients undergoing myocardial revascularization. The material was divided into two groups: patients undergoing a primary coronary bypass operation (Group P, n = 2298) and a smaller subset of patients undergoing repeat coronary bypass operation (Group R, n = 28). At least one internal mammary artery was grafted in 99% of the patients, with supplemental saphenous vein grafts. Intraoperatively, autologous heparinized blood was removed before bypass and retransfused at the conclusion of extracorporeal circulation. The volume remaining in the extracorporeal circuit was returned without cell processing or hemofiltration. Autotransfusion of the shed mediastinal blood was continued hourly up to 18 h after surgery in all patients. The mean postoperative mediastinal drainage in group R was 543 +/- 218 ml, compared to 703 +/- 340 ml in Group P (P = 0.01). In Group R, 1 patient (3.6%) received packed red cells and no patients were given other homologous blood products, compared to 33 patients (1.4%) given red cells and 35 patients (1.5%) given plasma transfusion in Group P (NS). Thus, in total, 2257 patients (97.0%) were not exposed to any homologous blood products during hospitalization. Total hemoglobin loss was significantly higher in Group R, resulting in a mean hemoglobin concentration at discharge of 109 +/- 13 g/l, compared to 121 +/- 14 g/l in Group P (P = 0.0002).(ABSTRACT TRUNCATED AT 250 WORDS)