Measuring the Kinetics of Neutral Pair Evaporation from Cluster Ions of Ionic Liquid in the Drift Region of a Differential Mobility Analyzer.

Singly charged clusters [C+A-]nC+ or [C+A-]nA- of two salts [C+A-] are produced by electrospray ionization of alcohol solutions of the ionic liquids 1-ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate (EMI-FAP) and 1,2-dimethyl-3-propylimidazolium-methide (DMPI-Me). The rate of neutral pair evaporation into [C+A-] + [C+A-]n-1C+ or [C+A-]n-1A- is studied in atmospheric pressure as a function of temperature T for the positive trimer ion (n = 2) of DMPI-Me and the negative trimer ion of EMI-FAP. The trimer is separated from all other electrosprayed ions in a first differential mobility analyzer (DMA1) and then transferred through a cooled tube to a second DMA whose drift gas is kept at a controlled temperature (25 °C < T < 100 °C). Singular characteristics of the DMA are a residence time τ of ∼0.1 to 1 ms, with essentially uniform temperature and τ. The decomposition occurring within DMA2 results in a complex mobility spectrum associated with dimer product ions, with apparent mobilities intermediate between those of the dimer and the trimer, depending on the product of the reaction rate k and τ. A theoretical expression yielding k from the shape of the collected mobility spectrum is obtained by accounting for the deterministic reactive, convective, and diffusive evolutions of the parent and product ions within DMA2. Observed and predicted mobility spectra agree well, yielding the reaction rate k with little ambiguity. Activation energies near 1 eV are determined for both trimer ions. Paradoxically, the evaporation process substantially heats up the cluster ion product. The theory developed enables measuring decay times much smaller and much larger than the residence time in the DMA.

Sternal plate closure: indications, surgical procedure and follow-up.

OBJECTIVES: Titanium plate osteosynthesis (Synthes) is an alternative option for sternal closure. The indications and time point of application are still debated. This study investigated the application and feasibility of this technique after median sternotomy. METHODS: Forty-one patients (29 M/12F, mean age 63 ± 17 years) received the plate system for complicated sternal conditions. Indications, intraoperative course and postoperative follow-up were assessed. RESULTS: Sternal deformity was present in 5 % (2/41), sternal fractures in 17 % (7/41), bone defect in 12 % (5/41), wire loosening in 39 % (16/41) and pseudoarthrosis in 27 % (11/41). 54 % (22/41) of patients showed concomitant sternal infection. Two intraoperative complications were noted: mammary artery injury (1 patient), pleural injury (1 patient). At discharge the patients reported no pain (90 %, 37/41) or only occasional discomfort (10 %, 4/41). Postoperative complications were subcutaneous hematoma in 12 % (5/41), seroma in 12 % (5/41) and sternal reinfection in 7 % (3/41). 12 % (5/41) showed occasional discomfort and 7 % (3/41) had persistent pain leading to plate removal. CONCLUSION: The Titanium Sternal Fixation System is comfortable and easy to use. It can be used to treat a wide spectrum of indications, especially for pseudoarthrosis, an entity which has not yet received sufficient attention.

Donor-derived aspergillosis from use of a solid organ recipient as a multiorgan donor.

The growing need for organs and the scarcity of donors has resulted in an increased use of extended criteria donors. We report a case where a recipient of a cardiac graft was used as an organ donor. Death of the recipient occurred 9 days after transplantation and was attributed to presumed cerebral hemorrhage, which post mortem was diagnosed as invasive aspergillosis of the brain. One recipient of a kidney transplant lost the graft due to infection with Aspergillus fumigatus, whereas prompt initiation of therapy successfully prevented disseminated aspergillosis in the other recipients. Despite the pressure to extend the use of organs by lowering the acceptance criteria, organs should only be accepted if the cause of death of the donors is unequivocally explained.

[Telemedicine: Who, what, with what aids, where, why, how, when?]. / Télémédecine: quis, quid, ubi, quibus auxiliis, cur, quomodo, quando?

Telemedicine can be defined as the practice of medicine or surgery via telecommunication interposition using technologies which permit the exchange of medical information and the application of medical care at a distance. Geographic separation, logistical problems which impede the delivery of care, extreme climactic conditions, artificial environments, or a combination of these parameters may all influence the health of patients and the ability of healthcare professionals to do their work effectively. This article reviews the standards of current telemedical and telesurgical systems, defines target groups who may benefit from such care, and details the technologic requirements of telemetry; it uses selected cases and a review the medical literature. The conclusion focuses on future developments and the potential for further improvements through ongoing research.

[Use of telemedicine in Switzerland]. / Applications de la télémédecine en Suisse.

In the 21st century, telemedicine has become daily business. Nevertheless, they are still a lack of precise definitions of telemedicine. Legal and financial implications of telemedical applications are complex, with lots of local restrictions, far beyond global technological aspects. In the United States, telemedicine is a reality since decades, and is basically defined as the provision of health care when distance separates the participants. Technology and networks for telemedicine are universally globalized, but the legal and financial implications are diametrically more local based. Any CT-scan made at midnight in Switzerland can be accurately assessed within minutes by any Australian radiologist, for whom it will be the morning, and so far around the globe at any time of the day or the night. But how will the billing work intercontinentally? And what about legal implications of this telemedical service? In this paper, we review the actual definitions of telemedicine, check our local legal responsibilities, and present the Tarmed financial positions for billing.

Epidemiologic variables and outcome of 1972 young patients with acute myocardial infarction. Data from the GISSI-2 database. Investigators of the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico (GISSI-2).

BACKGROUND: Acute myocardial infarction in younger patients is uncommon, occurring mainly in men. The recent introduction of thrombolysis improved survival, left ventricular function, and infarct size. OBJECTIVE: To evaluate characteristics and clinical outcome of the patients younger than 50 years randomized in the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico study. All patients received a thrombolytic treatment. METHODS: The 11483 patients were divided into 3 age subgroups: younger than 50 years (17.2%), between 50 and 70 years (60.2%), and older than 70 years (22.6%). All relations between variables were first determined by an unadjusted analysis. An adjusted analysis was performed by multiple logistic regression models for in-hospital and 6-month mortality. RESULTS: While older patients had a significantly higher rate of a history of hypercholesterolemia, diabetes, and hypertension, smoking and a positive family history were significantly more frequent in younger patients. Total in-hospital and 6-month mortality were significantly lower in patients younger than 50 years (2.7% and 1.2%, respectively) than in patients between 50 and 70 years old (6.9% and 2.7%) and those older than 70 years (21.1% and 8.4%). After multivariate analysis, the predictive value of age was confirmed. CONCLUSIONS: Our findings, based on a large group of patients who received thrombolytic treatment, suggest that younger age is a significant independent indicator of a favorable prognosis after acute myocardial infarction.

Off-pump coronary artery bypass grafting: the Zurich experience.

Coronary artery bypass grafting (CABG) is the surgical procedure of choice for treatment of multi-vessel coronary artery disease. The rising risk profile of the patients requiring isolated CABG and the economic pressure have prompted us to devise new operative strategies to treat these patients. Elimination of the cardiopulmonary bypass is one possible answer to the dilemma of maintaining the quality of care and reducing the exploding costs of our health system. Therefore, we developed the off-pump coronary artery bypass grafting (OPCAB) for patients requiring isolated CABG. In our experience the key to successful OPCAB relies on the order of revascularization of the myocardial walls (anterior, inferior, lateral), use of intracoronary shunt, no-touch technique for the proximal aortic anastomosis with heart string â (Guidant, IN, USA), close collaboration with the anesthesiologists, early and aggressive administration of anti-platelet therapy, endoscopic vein harvest by perfusionists, and improved body temperature control. Following these concepts, we have been able to offer the OPCAB procedure to over 90% of our patients and to reduce perioperative morbidity and global costs.

Cardiac surgery in a high-risk group of patients: is prolonged postoperative antibiotic prophylaxis effective?

OBJECTIVE: In a prospective, randomized study, postoperatively prolonged antibiotic prophylaxis is evaluated in a high-risk group of patients undergoing cardiac operations. These patients had postoperative low cardiac output necessitating inotropic support and intraaortic balloon pumping. METHODS: Between January 1991 and 1994, 53 patients were enrolled in the study (42 men, mean age 65 years). All patients received the usual perioperative (24 hours) cefazolin prophylaxis. In the study group (n = 28) a prolonged regimen of prophylaxis with ticarcillin/clavulanate was performed for 2 days and vancomycin was added in a low dose until removal of the intraaortic balloon pump. The control group (n = 25) did not receive a prolonged regimen of prophylaxis. Follow-up ended at hospital discharge. RESULTS: Early mortality was 7 of 28 patients (25%) in the prophylaxis group and 8 of 25 patients (32%) in the control group (p = 0.397). Defined infections (pneumonia, n = 22; sepsis, n = 8; deep sternal wound infection, n = 2) occurred in 50% of the study group and 68% of the control group (p = 0.265). In all patients with septicemia, only coagulase-negative staphylococci could be isolated from the bloodstream (5 patients in the prophylaxis group vs 3 in the control group). Infectious parameters were controlled daily and did not differ significantly between groups. A total of 1158 bacteriologic tests were performed (blood cultures, n = 389; intravascular catheters, n = 208; bronchial aspirates, n = 411; intraaortic balloon pumps, n = 42; wound secretions, n = 108) showing bacterial growth in 322 (28%) without a significant difference between the groups. In the prophylaxis group, 13 intravascular catheters and intraaortic balloon pumps showed bacterial growth versus 11 in the control group. No side effects were seen. CONCLUSIONS: In a high-risk group of patients undergoing cardiac operations, infectious outcome could not be effectively influenced by an additional and prolonged postoperative prophylaxis regimen with low-dose vancomycin and ticarcillin/clavulanate. Low-dose vancomycin did not reduce the rate of infections or colonizations of intravascular catheters with gram-positive organisms.

New approach to patency and flow assessment after left internal thoracic artery hypoperfusion syndrome with additional saphenous vein graft to the left anterior descending artery with phase-contrast magnetic resonance angiography.

OBJECTIVE: Perioperative and early postoperative flow reduction of a left internal thoracic artery conduit is a rare complication of myocardial revascularization and may lead to the potentially fatal left internal thoracic artery hypoperfusion syndrome. It has been advocated that an additional vein graft be placed to the distal left anterior descending artery to provide sufficient myocardial perfusion. Some evidence exists, however, that this high-flow vein might lead to competing or even backward flow through the internal thoracic artery. METHODS: In the past 2 years, 21 patients received an additional vein graft to the distal left anterior descending artery for left internal thoracic artery hypoperfusion syndrome. Nineteen of these patients were available for magnetic resonance imaging. Early (< 6 months) and late (> 12 months) postoperative flow measurements, both in the left internal thoracic artery and in the saphenous vein grafts, were performed by means of conventional and a segmented k-space phase-contrast magnetic resonance angiography technique. RESULTS: Early magnetic resonance examinations indicated that all conduits had adapted to the coronary flow type with predominant diastolic perfusion. Patency rate both at the early and at the late study was 100%. No concurrent flow, flow reversal, or steal phenomena were observed. Mean flow rates were 49.2 ml/min for the left internal thoracic artery and 72.6 ml/min for the saphenous vein graft. CONCLUSION: On the basis of the flow data obtained with magnetic resonance angiography, the use of an additional saphenous vein graft as the treatment of choice in left internal thoracic artery hypoperfusion syndrome does not lead to occlusion of the artery. Conduit flow adaptation to the diastolic predominance occurs in the first 6 months after operation.

Surgical management of severe common carotid artery injury after mediastinoscopy.

Mediastinoscopy is a widely used method to achieve pathologic diagnosis of enlarged lymph nodes or undefined mediastinal solid mass. Aortic arch penetration and injury of the supraaortic arteries are rare but very dangerous complications of mediastinoscopy. We describe the hazardous transportation of a 57-year-old woman after mediastinoscopic injury of the right common carotid artery and its successful repair with cardiopulmonary bypass and deep hypothermia.

Mesenteric ischemia after a cardiac operation: conservative treatment with local vasodilation.

Acute mesenteric ischemia is a rare and often fatal event after cardiopulmonary bypass. We describe a diagnostic and therapeutic algorithm and present a patient with nonocclusive intestinal ischemia who had a successful conservative treatment.

Minimally invasive coronary artery bypass techniques as adjunct to extracardiac procedures.

BACKGROUND: Surgical management of coronary artery disease has improved dramatically over the last decades in terms of short- and long-term results. Nevertheless, elderly patients (more than 75 years); patients with reduced ejection fraction (less than 0.25), heavily calcified aorta, or coexisting noncardiac diseases; and patients requiring cardiac reoperation have an increased perioperative risk when operated on with cardiopulmonary bypass. Successful minimally invasive coronary artery bypass grafting without cardiopulmonary bypass has been reported in selected cases. METHODS: In 8 of 40 high-risk patients undergoing operation on a beating heart, minimally invasive coronary bypass grafting was combined with vascular (carotid endarterectomy, n = 3; aortic replacement, n = 2) and abdominal procedures (a second look after combined pancreas and kidney transplantation) or defibrillator implantations (n = 2). RESULTS: Postoperatively, there was no mortality, no morbidity, and no blood transfusion. Patients are free of symptoms at an average follow-up time of 5.5 +/- 5 months. CONCLUSIONS: Our results indicate that minimally invasive coronary artery bypass grafting technique can be particularly useful if noncardiac procedures have to be performed in high-risk patients with significant coronary artery disease.

Drainage of the inferior vena cava to the left atrium.

This report describes a 7-year-old girl with an anomalous connection between the inferior vena cava and the left atrium documented with intraoperative transesophageal color-coded Doppler flow echocardiography and angiography. This rare congenital disorder should be considered in the differential diagnosis in patients with cyanosis without cardiac murmurs. Operation is the only method for correction.

Treatment of left atrial dissection after mitral repair: internal drainage.

Two patients with intraoperative dissection of the entire left atrium after mitral valve repair are presented. Intraoperative transesophageal echocardiography detected left atrial dissection with formation of a large cavity compressing the left atrium. The false lumen was opened and widely connected to the right atrium to perform the decompression. This technique permits the runoff into the low pressure system in case of persisting hemorrhage from the unknown entry, and eliminates the risk of systemic embolization from the cavity.

Prevention of residual ventricular septal defects with fibrin sealant.

BACKGROUND: Modern echocardiography now allows for the detection of a substantial number of residual ventricular septal defects (VSDs) after surgical patch repair that remained hidden in the past. Mostly without hemodynamic significance, residual VSDs may have clinical consequences (progressive dehiscence, hemolysis, prophylactic antibiotic treatment, endocarditis). To reduce the number and size of residual VSDs we performed an experimental and a clinical study. METHODS: (1) In an experimental setup, burst pressure of 60 fibrin glue-sealed defects (calibrated between 1.0 and 5.0 mm in diameter) was determined using a computerized recording system and pressure loads up to 500 mm Hg. (2) In a prospective clinical trial with blinded postoperative echocardiographic controls VSD closure was performed in 36 consecutive patients (age, 37 +/- 40 months; range, 4 to 134 months) using a polytetrafluoroethylene patch and running sutures reinforced with pledgets (22 of 36 patients) or sealed with fibrin glue (14 of 36 patients) in accordance to the surgeon's preference. RESULTS: (1) Experimentally, mean pressure load achieved was more than 500 +/- 0 mm Hg for 1.0-mm defects, 413 +/- 52 mm Hg for 2.5-mm defects, 363 +/- 58 mm Hg for 4.0-mm defects, and 313 +/- 48 mm Hg for 5.0-mm defects (r 0.873, p < 0.001). (2) Clinically, all patients survived. Residual VSDs at echocardiography were observed in 16 of 22 patients (72%) for reinforced versus 5 of 14 patients (36%) for sealed with fibrin glue (p < 0.05). Diameter of residual VSDs accounted for 1.3 +/- 1.2 mm for reinforced versus 0.3 +/- 0.4 mm for sealed with fibrin glue (p < 0.01). Hemodynamically significant residual VSDs were fond in 2 of 22 patients (9%) for reinforced versus 0 of 14 patients (0%) for sealed with fibrin glue (p = not significant). CONCLUSIONS: Small defects sealed with fibrin glue resist physiologic pressure load. Fibrin glue sealing of prosthetic patches during intracardiac VSD repair allows for significant reduction of number and size of residual VSDs. Improved long-term outcome can be expected.

Disadvantages of local repair in acute type A aortic dissection.

BACKGROUND: In acute type A dissection of the aorta, local repair with glue-aortoplasty was compared with aortic replacement. METHODS: Between 1992 and 1996, 106 consecutive patients (mean age, 59 years; 84 men) were operated on average 14.5 hours after onset of dissection. A local repair (gelatin-resorcine-formaldehyde/glutaraldehyde glue, Trigon AG, Monchengladbach, Germany) without graft replacement was performed in 21 patients. Graft replacement and reinforcement of aortic stumps with gelatin-resorcine-formaldehyde/glutaraldehyde glue was performed in 85 patients (supracoronary graft, 68; aortic root replacement, 17). RESULTS: Survival was 79% after 30 days and 69% after 2 years. There was no difference in early mortality (p = 0.2240) and survival (p = 0.07649). Risk factors for early mortality were preoperative shock, neurologic disorder, duration of crossclamp, and extracorporeal circulation. The rate of reoperation on the proximal aorta was 31.6% (6 of 19) after local repair and 9% (6 of 64) after aortic replacement (p = 0.0157). Local repair was a significant predictor for reoperation (p = 0.0087), with decreased reoperation-free survival (p = 0.01164). In all reinterventions (four supracoronary grafts, including two valve replacements; two composite grafts; two arch replacements) breakdown of the aortoplasty was confirmed. CONCLUSION: Local repair has satisfactory early results but an increased incidence of reoperations due to a breakdown of the glue-aortoplasty. Indications for local repair should be restricted to high-risk patients requiring a minimal emergency surgical procedure.

Eradication of aortic infections with the use of cryopreserved arterial homografts.

BACKGROUND: The surgical treatment of vascular infection is associated with a substantial early and late mortality. Cryopreserved homografts were evaluated for in situ reconstruction in aortic infections. METHODS: Between January 1991 and July 1995, homografts were used in 19 patients (mean age, 61 +/- 13 years; range, 40-85 years) with mycotic aneurysms (9/19; 47%) or infected grafts (10/19; 53%) in the thoracic (7/19; 37%) or abdominal (12/19; 63%) aorta. Sepsis was present preoperatively in 14 of 19 (74%) patients, and 18 of 19 (95%) had received antibiotic treatment for 6.4 +/- 6 months (range, 1-36 months). Up to ten previous vascular procedures had been done in 11 of 19 patients (58%). RESULTS: There was one (5.2%) early and two (11%) late deaths, with one (5.5%) of the late deaths being homograft related. The mean hospital stay was 27 +/- 26 days (range, 7-84 days). Antibiotics were given postoperatively for 30 +/- 12 days (range, 4-84 days). During the follow-up period of 18.6 +/- 13 months (range, 7-60 months), there were no instances of reinfection, suture line rupture, homograft stenosis, or anastomotic aneurysms. CONCLUSIONS: Cryopreserved arterial homografts allow safe in situ reconstruction, decrease early and midterm mortality, and reduce antibiotic requirements. Early and midterm reoperations are unnecessary.

Traumatic ventricular septal defect.

A 26 year old man was admitted to hospital following a traffic accident. He had been sitting in the back of a car without wearing a seat belt. He suffered crush injuries on the anterior chest wall, trunk, and legs. On admission he was awake and cooperative, but restless, and obviously in severe pain. Radiography of the skull, facial bones, chest, spine, pelvis, and legs revealed a shaft fracture of the left femur and tibia and fracture of the 7th and 8th right ribs. The patient was transferred to the University Hospital of Zurich for further assessment and surgical repair of the lower limb fractures three days later. Because of worsening clinical condition with onset of partial respiratory insufficiency and new loud systolic murmur at the left sternal edge, a transthoracic echocardiography was performed, which showed an apical ventricular septal defect. Surgery was performed immediately. The ventricular septal defect was successfully repaired using a Teflon felt patch and interrupted sutures with pledgets, and sealed with glue. At six months' follow up the patient was doing well. Ventricular septal defects after blunt chest trauma occur either because of heart compression between sternum and the spine or because of myocardial infarction. In the present case the ventricular septal defect appeared three days after the accident, probably secondary to a post-traumatic myocardial infarction. Patients with blunt chest trauma and suspicion of cardiac contusion should be monitored carefully.

Pregnancy after atrial repair for transposition of the great arteries.

OBJECTIVE: To investigate the risk of pregnancy in patients with transposition of the great arteries (TGA) who have undergone atrial repair. DESIGN: Retrospective analysis (1962-94) of 342 TGA patients who underwent atrial repair. Of 231 known late survivors, 48 were women over 18 years old who were interviewed about possible reproductive plans and previous pregnancies. As a control, comparison was made with data of 57 500 women (mean age 26 years) obtained from the Swiss Statistical Bank in Bern. RESULTS: Mean follow up was 13.7 years; 66% remained asymptomatic, 29% had mild to moderate cardiac symptoms, and 5% suffered from severe cardiac symptoms (New York Heart Association grade III-IV). Thirty six of the 48 women wished to bear children and, to date, there have been 10 live births, two spontaneous first trimester abortions, and one induced abortion at 16 weeks. During pregnancy there was one case of cardiac deterioration and two cases of pneumonia. There was no evidence of congenital heart disease in the children. CONCLUSIONS: In this relatively small series the completion of pregnancy in women with TGA who had undergone atrial repair and who had normal functional cardiac status was uncomplicated

Does the morphology of mitral paravalvular leaks influence symptoms and hemolysis?

BACKGROUND AND AIM OF THE STUDY: Prosthetic mitral valve replacement (MVR) is associated with paravalvular leak in up to 12.5% of patients. The influence of the morphology and location of paravalvular leaks on clinical symptoms and degree of leak-related hemolysis is unknown. METHODS: Morphology, size, location and number of paravalvular leaks were analyzed in 96 consecutive patients with primary mitral paravalvular leaks. RESULTS: Mitral leak was diagnosed a median of 119 days after primary MVR. A small (1-2 mm) paravalvular leak was found in 41 patients (43%), an intermediate leak (3-5 mm) in 26 (27%), and a large leak (6-15 mm) in 29 (30%). Single leaks were observed in 70 patients (73%), whilst 26 (27%) had multiple leaks. Paravalvular leaks occurred around the entire prosthetic circumference, but were seen predominantly around the mitral commissural areas (76%). The larger the size of the leak, the more symptomatic the patient (p = 0.006); 80% of patients with small leaks were in NYHA classes I and II, whilst 62% with intermediate/large leaks were in NYHA classes III and IV. The number of leaks was not correlated with severity of clinical symptoms. Multiple leaks were more likely to cause significant hemolysis. Patients with preoperative chronic renal insufficiency, postoperative infection or large (>5 cm) left atria were more likely to develop multiple leaks. The size and location of the leaks was surgeon-dependent. CONCLUSION: Intraoperative transesophageal echocardiography is mandatory to detect possible small leaks and technical errors. Strict monitoring of all MVR patients is necessary for prolonged periods, as the appearance of paravalvular leaks is not necessarily correlated with clinical symptoms. Small paravalvular leaks, in particular, may go unnoticed. As the location and size of the leaks were significantly surgeon-dependent, self-monitoring should be mandatory for all surgeons.