Biomedical subjects

T Busch

Publications and source records attributed to T Busch.

At least 37 records · Page 2Linked to original sources

PubMed2001

Small dose of exogenous surfactant combined with partial liquid ventilation in experimental acute lung injury: effects on gas exchange, haemodynamics, lung mechanics, and lung pathology.

A combination of exogenous surfactant and partial liquid ventilation (PLV) with perfluorocarbons should enhance gas exchange, improve respiratory mechanics and reduce tissue damage of the lung in acute lung injury (ALI). We used a small dose of exogenous surfactant with and without PLV in an experimental model of ALI and studied the effects on gas exchange, haemodynamics, lung mechanics, and lung pathology. ALI was induced by repeated lavages (PaO2/FIO2 less than 13 kPa) in 24 anaesthesized, tracheotomized and mechanically ventilated (FIO2 1.0) juvenile pigs. They were treated randomly with either a single intratracheal dose of surfactant (50 mg kg(-1), Curosurf, Serono AG, München, Germany) (SURF-group, n=8), a single intratracheal dose of surfactant (50 mg kg(-1), Curosurf) followed by PLV with 30 ml kg(-1) of perfluorocarbon (PF 5080, 3M, Germany) (SURF-PLV-group, n=8) or no further intervention (controls, n=8). Pulmonary gas exchange, respiratory mechanics, and haemodynamics were measured hourly for a 6 h period. In the SURF-group, the intrapulmonary right-to-left shunt (QS/QT) decreased significantly from mean 51 (SEM 5)% after lavage to 12 (2)%, and PaO2 increased significantly from 8.1 (0.7) to 61.2 (4.7) kPa compared with controls and compared with the SURF-PLV-group (P<0.05). In the SURF-PLV-group, QS/QT decreased significantly from 54 (3)% after induction of ALI to 26 (3)% and PaO2 increased significantly from 7.2 (0.5) to 30.8 (5.0) kPa compared with controls (P<0.05). Static compliance of the respiratory system (C(RS)), significantly improved in the SURF-PLV-group compared with controls (P<0.05). Upon histological examination, the SURF-group revealed the lowest total injury score compared with controls and the SURF-PLV-group (P<0.05). We conclude that in this experimental model of ALI, treatment with a small dose of exogenous surfactant improves pulmonary gas exchange and reduces the lung injury more effectively than the combined treatment of a small dose of exogenous surfactant and PLV.

Animals↗

PubMed2001

Hypoxia decreases exhaled nitric oxide in mountaineers susceptible to high-altitude pulmonary edema.

An exaggerated hypoxic pulmonary vasoconstriction is essential for development of high-altitude pulmonary edema (HAPE). We hypothesized that susceptibility to HAPE may be related to decreased production of nitric oxide (NO), an endogenous modulator of pulmonary vascular resistance, and that a decrease in exhaled NO could be detected during hypoxic exposure. Therefore, we investigated respiratory tract NO excretion by chemiluminescence and pulmonary artery systolic pressure (Ppa,s) by echocardiography in nine HAPE-susceptible mountaineers and nine HAPE-resistant control subjects during normoxia and acute hypoxia (fraction of inspired oxygen [FI(O2)] = 0.12). The subjects performed oral breathing. Nasally excreted NO was separated from respiratory gas by suction via a nasal mask. In HAPE-susceptible subjects, NO excretion in expired gas significantly decreased (p < 0.05) during hypoxia of 2 h in comparison with normoxia (28 +/- 4 versus 21 +/- 2 nl/min, mean +/- SEM). In contrast, the NO excretion rate of control subjects remained unchanged (31 +/- 6 versus 33 +/- 6 nl/ min, NS). Nasal NO excretion did not differ significantly between groups during normoxia (HAPE-susceptible group, 183 +/- 16 nl/ min; control subjects, 297 +/- 55 nl/min, NS) and was not influenced by hypoxia. The changes in Ppa,s with hypoxia correlated with the percent changes in lower respiratory tract NO excretion (R = -0.49, p = 0.04). Our data provide the first evidence of decreased pulmonary NO production in HAPE-susceptible subjects during acute hypoxia that may contribute among other factors to their enhanced hypoxic pulmonary vascular response.

Adult↗

PubMed2001

Single atriocaval cannulation is associated with increased incidence of hypercirculatory failure after cardiopulmonary bypass.

UNLABELLED: Cardiopulmonary bypass (CPB) can lead to hypercirculatory cardiac failure (HCF). Despite the activation of inflammatory mediators, the infusion of cardioplegic solution into the systemic circulation may result in decreased systemic vascular resistance and thus may cause HCF. The present prospective study was conducted to investigate in cardiac surgical patients the effects of single atrial versus bi-caval venous drainage and intraoperative hemofiltration on the incidence of HCF. METHODS AND RESULTS: 120 patients undergoing coronary artery bypass surgery (CABG) were randomized in 3 groups: A- single atrial cannulation; B- single atrial cannulation and intraoperative zero fluid balance hemofiltration; C- bi-caval cannulation. Myocardial protection was performed using cold crystalloid cardioplegia (Bretschneider's HTK) administrated into the aortic root and moderate hypothermia (32 degree C). Hemodynamics, fluid balance, vasoactive drugs, body temperature, and hemoglobin/hematocrit ratio were recorded during and up to 12 hours after surgery. We noted a significantly increased incidence of HCF in-group A (32%, n=13) and B (40%, n=16) when compared to group C (10%, n=4, p<0.05), with significantly increased requirements for vasoactive medication in patients developing HCF. CONCLUSION: The present study results demonstrate that single atrial cannulation is associated with a significantly higher incidence of HCF. This is presumably caused by infusion of cardioplegic solution into the systemic circulation.

Aged↗

PubMed2001

Bronchopleural fistula in the surgery of non-small cell lung cancer: incidence, risk factors, and management.

BACKGROUND: The incidence of a bronchopleural fistula (BPF) as a major complication after non-small cell lung carcinoma (NSCLC) surgery has decreased in recent years, due to new surgical refinements and a better understanding of the bronchial healing process. We reviewed our most recent experience with BPFs and tried to determine methods which may effectively reduce its occurrence. METHODS: Data on 490 patients with lung resections for NSCLC over a period from 1990 to 1999 were retrospectively reviewed. Details regarding surgery and the subsequent treatment were carefully reviewed. Particular attention was paid to factors possibly affecting the occurrence of BPFs: the technique of the initial bronchial closure, previous radiation and/or chemotherapy, need for postoperative ventilation and presence of residual carcinomatous tissue at the bronchial suture line. Information about age, sex, clinical diagnosis, associated conditions, TNM stage, period between primary operation and rethoracotomy and postoperative outcome was also recorded. RESULTS: The overall BPF incidence was 4.4% (22/490). There were 21 (95.5%) males and 1 (4.5%) female, mean age was 57.8 years. BPFs occurred after pneumonectomy in 12 (54.6%), after lobectomy in 9 (40.9%) patients and after sleeve resections in 1 (4.5%) patient. Mortality rate was 27.2% (6/22). Right-sided pneumonectomy and postoperative mechanical ventilation were identified as risk factors for BPFs (p<0.05). Initial chest re-exploration was performed in 20 (90.9%) patients. After debridement, the bronchial stump was reclosed by hand suture in 10 (45.4%) patients. All 10 (45.4%) patients with a post-lobectomy- and sleeve resection BPF necessitated completion surgery. The BPF was additionally covered with a vascularized flap in 20 (90.9%) patients. In 2 (9%) patients with small BPFs and poor overall condition the initial treatment was endoscopic. In both the fistula persisted and the stump had to be surgically resutured. CONCLUSIONS: A BPF remains a major complication in the surgery of NSCLC because of its high mortality and morbidity rate. A BPF is more common after right-sided pneumonectomy and is frequently associated with postoperative mechanical ventilation. The management varies according to the initial type of surgery, the size of the BPF, the overall patient condition and that of the remaining lung. Endoscopic treatment is reserved only for small fistulas associated with poor general condition.

Adult↗

PubMed2000

Improvement of impaired renal function in heart transplant recipients treated with mycophenolate mofetil and low-dose cyclosporine.

BACKGROUND: Cyclosporine (CsA) nephrotoxicity is a common problem after cardiac transplantation. We have studied the impact of CsA dose reduction in association with mycophenolate mofetil (MMF) treatment on renal function in heart transplant recipients with suspected CsA nephrotoxicity (serum creatinine level >2 mg/dl). METHODS: Twelve heart transplant recipients (11 men, 1 woman; 111 to 1813 days after transplantation) with CsA-based immunosuppression (plus azathioprine and/or steroids) and a serum creatinine level >2.0 mg/dl were started on a daily dose of 2000 mg of MMF. Dilated cardiomyopathy was the underlying disease in nine patients, ischemic cardiomyopathy in three patients. Mean patient age was 57 years (range 44-69 years). Azathioprine was discontinued and CsA slowly tapered. Creatinine clearance, serum creatinine level, urea nitrogen, and uric acid were monitored. CsA levels were measured, and CsA dose was adjusted for whole blood levels of 70-120 microg/L. Ten patients still had endomyocardial biopsies, whereas one had echocardiographic controls only. RESULTS: One grade 1B rejection episode according to ISHLT (International Society for Heart and Lung Transplantation) was observed until 1 year after the switch to MMF. One patient was excluded due to gastrointestinal side effects. CONCLUSIONS: Conversion from azathioprine to MMF with consecutive reduction of CsA in heart transplant recipients with CsA-impaired renal function improves renal function as evidenced by lower serum creatinine, urea nitrogen, uric acid, and higher creatinine clearance.

Adult↗

PubMed2000

Motion of dark solitons in trapped bose-einstein condensates

We use a multiple time scale boundary layer theory to derive the equation of motion for a dark (or grey) soliton propagating through an effectively one-dimensional cloud of Bose-Einstein condensate, assuming only that the background density and velocity vary slowly on the soliton scale. We show that solitons can exhibit viscous or radiative acceleration (antidamping), which we estimate as slow but observable on experimental time scales.

Journal Article↗

PubMed2000

Inhaled endothelin A antagonist improves arterial oxygenation in experimental acute lung injury.

OBJECTIVES: To study the effects of an inhaled endothelin A (ET(A)) receptor antagonist on hemodynamics and pulmonary gas exchange in experimental acute lung injury (ALI). DESIGN AND SETTING: Prospective, randomized, and controlled study in a university laboratory. PARTICIPANTS AND INTERVENTIONS: Sixteen pigs were ventilated in a volume controlled mode during general anesthesia. ALI was induced by surfactant depletion using repetitive lung lavages until the PaO2/FIO2 ratio was below 100 mmHg. The animals were then randomly assigned to receive either a nebulized ET(A) receptor antagonist (LU-135252, 3 mg/kg, inhaled over 1 h; LU group) or nebulization of saline (5-10 ml inhaled over 1 h) with no further intervention (controls). MEASUREMENTS AND RESULTS: Parameters of hemodynamics and gas exchange were measured for 6 h after induction of ALI. In the LU group intrapulmonary right-left shunting (QS/QT) decreased from 58 +/- 8% at the onset of ALI to 27 +/- 12% 3 h and 24 +/- 9% 6 h after ALI (p < 0.05); PaO2 increased from 55 +/- 12 to 257 +/- 148 mmHg 3 h and 270 +/- 136 mmHg 6 h after ALI. (p < 0.05), whereas in controls QS/QT and PaO2 did not improve over the 6 h after onset of ALI. In the LU group mean pulmonary artery pressure was stable for 6 h after ALI (26-29 mmHg), while in controls it increased from 28 +/- 2 to 41 +/- 2 mmHg (p < 0.05). Inhaled LU-135252 reduced cardiac output by 31 +/- 11% (p < 0.05) and increased systemic vascular resistance by 60 +/- 29 % (p < 0.05), while these parameters remained stable in controls. CONCLUSION: In this porcine model of ALI the inhalation of an ET(A) receptor antagonist improved arterial oxygenation and maintained a stable pulmonary artery pressure without inducing systemic vasodilatation.

Administration, Inhalation↗

PubMed2000

Nasal, pulmonary and autoinhaled nitric oxide at rest and during moderate exercise.

OBJECTIVE: To investigate nasal nitric oxide (NO) excretion, pulmonary NO excretion, and autoinhalation of nasally released NO at rest compared with that during moderate exercise in smokers and non-smokers. DESIGN: Prospective observational study. SETTING: University laboratory. PARTICIPANTS: Fourteen healthy adult volunteers. INTERVENTIONS: Breathing of NO-purified air supplied via a tube system at rest and during a bicycle-ergometer workload of 60 Watt over a time of 10 min. MEASUREMENT AND RESULTS: We examined nasal and pulmonary NO excretion in smoking (n = 7) and non-smoking (n = 7) adult human volunteers. At rest, we measured constant nasal NO excretion rates of 311 +/- 89 nl/min for non-smokers and 261 +/- 142 nl/min for smokers (mean +/- SD, n.s.). During 60 W exercise, nasal NO release remained unchanged, while pulmonary NO excretion doubled compared with the rates at rest (non-smokers: 40 +/- 21 nl/min versus 23 +/- 14 nl/min, p < 0.05; smokers: 41 +/- 8 nl/min versus 22 +/- 8 nl/min, p < 0.05). The differences between smokers and non-smokers in nasal or pulmonary NO excretion were not significant. To determine the autoinhaled amount of nasally released NO, we also measured the NO concentration within the nasopharynx of five volunteers during nasal breathing. The average inhaled NO concentration was 17.8 +/- 3.1 ppb at rest and this decreased to 9.3 +/- 1.8 ppb during exercise of 60 W, while minute ventilation approximately doubled from 9 +/- 2 to 21 +/- 3 l/min. CONCLUSION: Our results demonstrate that moderate exercise increased exclusively pulmonary NO excretion. Nasal NO release, which is 10 times higher at rest, was not changed. The decrease in autoinhaled NO concentration during exercise results from dilution of the continuous nasal release by the increased respiratory gas flow. The individual NO release allows no conclusion about smoking habits.

Adult↗

PubMed2000

Giant localized fibrous mesothelioma: an unusual large intrathoracic tumor.

BACKGROUND: Localized fibrous mesotheliomas are rare intrathoracic tumors arising from the pleural tissue. They are mostly benign tumors, with dimensions ranging from a small nodule to a large intrathoracic tumor. CASE: This paper describes the presence of giant localized fibrous mesothelioma filling the lower left pleural cavity, which developed over a 20-year period. Surgical resection of the tumor showed a large, localized fibrous mesothelioma 14 cm in diameter. CONCLUSIONS: The clinical manifestations of localized fibrous mesotheliomas are very variable. Small tumors may be asymptotic, while large tumors may cause respiratory, cardiac or metabolic symptoms. Complete surgical resection is the preferred treatment and is usually curative. Careful follow-up is indicated because recurrence may occur, even many years after the initial operation.

Aged↗

PubMed2000

Chyloperitoneum: a rare complication after abdominal aortic aneurysm repair.

We report a case of chylous ascites as a rare complication following elective aortic aneurysm repair in a 66-year-old male. After early development of this condition on the second postoperative day, relaparotomy was performed with ligation of fistulae as well as omentoplasty. After recurrence of chylous ascites, conservative treatment consisting of parenteral nutrition and a low-fat diet for 3 months along with continuous peritoneal drainage finally led to successful resolution of this complication.

Aged↗

PubMed2000

Retrocardiac arteriovenous malformation causing recurrent cerebral ischemia.

A 28-year-old woman had been suffering from recurrent cerebral embolizations for almost 9 years. A retrocardiac arteriovenous malformation was identified as the source of emboli. It was supplied by chest wall veins and the right upper pulmonary vein, connected to the back wall of the left atrium and a possibly aberrant hepatic vein originating from the abdomen. The aneurysm was resected and all supplying veins ligated. The vein from below the diaphragm was implanted into the right atrium. Her postoperative course was uncomplicated. Long-term follow-up free from cerebrovascular events.

Adult↗

PubMed2000

Importance of cardiovascular interventions before surgery for abdominal aortic aneurysms.

Preoperative screening, and interventional and surgical therapy of cardiovascular diseases are of pivotal importance for successful outcome after abdominal aortic aneurysm surgery. In a retrospective study, all patients who underwent surgery for abdominal aortic aneurysm were reevaluated by preoperative diagnostic and therapeutic interventions for cardiovascular disease. Two study periods (1980-1989 and 1990-1996) were compared. Of 603 patients operated upon for abdominal aortic aneurysm between 1980 and 1996, 449 had surgery on an elective basis and 154 as an emergency. Preoperative diagnostic studies for coronary artery disease were performed on elective patients and were positive in 76.8% (1980-1989, 76.1%, 1990-1996, 77.5%). Coronary angiography was performed in 108 patients (29.6%). Medical therapy of coronary artery disease declined by 2.3%, and interventional procedures by 18.8%. In contrast, myocardial revascularization with subsequent aneurysm resection increased by 26.6% and 12 patients (16%) required urgent simultaneous cardiac and aortic surgery. Early mortality after abdominal aortic aneurysm surgery decreased from 4.2 to 2.9%, and the frequency of primary cardiac failure as the cause of death was reduced from 33.3 to 22.2% (P < 0.05). It was concluded that 42.6% more cardiac surgical procedures were performed before abdominal aortic aneurysm surgery since 1990 compared with the period 1980-1989. In contrast, the number of interventional procedures fell by 18.8%. Surgical therapy of cardiac disease reduces early mortality after elective abdominal aortic aneurysm surgery.

Aged↗

PubMed2000

Complex traumatic dissection of right vertebral and bilateral carotid arteries: a case report and literature review.

A 27-year-old female motorcycle passenger was admitted with bruises and concussion after a motor-vehicle accident. After a lucid interval of several hours she became stuporous and progressed to an acute comatose state. Computed tomography demonstrated extensive cerebral ischaemia in the territory of the right middle cerebral artery. Angiography after transfer to the authors' hospital revealed dissections of both carotid arteries and of the right vertebral artery. The patient underwent surgical reconstruction of the left internal carotid artery with saphenous vein. The management of this patient is discussed and the literature reviewed.

Accidents, Traffic↗

PubMed2000

Ischaemic complications with intra-aortic balloon counter-pulsation: incidence and management.

The most important limitation of the use of the intra-aortic balloon pump is the risk of vascular complications. The aim of this study was to identify risk factors and aspects of diagnosis and management that may decrease the risk of vascular morbidity associated with intra-aortic balloon pumps. Risk factors, surgical techniques, complications and other variables were retrospectively evaluated in 524 patients who had an intra-aortic balloon pump inserted between January 1988 and December 1998. Of the total, 140 (26.7%) patients with an intra-aortic balloon pump had ischaemic complications that needed surgery. The mean age was 65.2 +/-12.3 years (66.7% men and 27.5% women). The mortality rate was 28.1%. The mortality for patients with ischaemic vascular complications was significantly higher than in those patients without (59.6 versus 30.1%, P = 0.001). One-hundred and eight (77.2%) ischaemic complications occurred during therapy with an intra-aortic balloon pump and 32 (22.8%) complications after intra-aortic balloon pumping had been stopped. Thromboembolectomy was required in 71 (50.7%) patients. Associated surgical procedures were performed in 69 (49.3%) patients. A history of peripheral vascular disease (43.6 versus 23.6%, P < 0.05) and the presence of diabetes mellitus (49.2 versus 16.9%, P < 0.05) increased the risk of limb ischaemia significantly. Limb ischaemia remains the major complication after intra-aortic balloon pump insertion. Independent predictors for vascular complications included peripheral vascular disease and diabetes. Intra-aortic balloon pump removal and thrombectomy is usually sufficient to provide revascularization. Identification of subclinical disease may aid in the management of subsequent acute limb ischaemia.

Age Factors↗

PubMed2000

Comparison of ventilatory and haemodynamic effects of BIPAP and S-IMV/PSV for postoperative short-term ventilation in patients after coronary artery bypass grafting.

The aim of the present multiple cross-over study was to compare the effects of biphasic positive airway pressure (BIPAP) ventilation with synchronized intermittent mandatory ventilation combined with pressure support ventilation (S-IMV/PSV) in sedated and awake patients after coronary artery bypass grafting (CABG) surgery. Twenty-four patients with no evidence of preoperative respiratory dysfunction and an uncomplicated intraoperative course were investigated. The patients were randomly assigned to one of two groups starting with either BIPAP or S-IMV/PSV mode. Haemodynamic measurements and blood gas analyses were performed during sedation with 2.0 mg kg(-1) h(-1) propofol in the primary mode, after switching to the alternative ventilatory mode, and in the primary mode again. The same sequence of measurements was repeated in awake patients who had reached extubation criteria. In awake patients, PSV was performed instead of S-IMV. Statistical analysis of data was performed using non-parametric tests. Inspiratory peak pressure increased significantly during S-IMV/PSV in sedated patients in both groups. Other ventilatory parameters did not differ significantly between BIPAP and S-IMV/PSV in both groups. Similarly, haemodynamic parameters and blood-gas analyses did not vary with the ventilatory mode. Our results demonstrate that BIPAP ventilation has comparable effects on haemodynamics and pulmonary gas exchange compared with S-IMV/PSV and PSV when used for short-term ventilatory support in patients after cardiac surgery.

Aged↗

PubMed2000

Pulmonary arteriovenous fistula drainage into the left atrium.

Arteriovenous fistulas with venous drainage into the left atrium are a rare anomaly. Although the etiology of pulmonary arteriovenous fistulas is unknown, these abnormalities are considered to have occurred during early fetal development. A case of this malformation in a 72-year-old woman successfully treated by surgery is described.

Aged↗

PubMed2000

Myocardial consequences of remifentanil in patients with coronary artery disease.

Remifentanil may be an alternative to conventional opioids for minimally invasive direct coronary artery bypass surgery because of its extremely short duration of action. The aim of this study was to investigate the effects of remifentanil on myocardial blood flow, metabolism and systemic haemodynamic variables in patients with coronary artery disease. After approval by the local ethics committee, 12 male patients were investigated before elective coronary artery bypass grafting. Systemic haemodynamic variables, myocardial blood flow and metabolism were measured when patients were awake and when they were anaesthetized with high-dose remifentanil (2.0 micrograms kg-1 min-1), or with remifentanil 0.5 microgram kg-1 min-1 combined with propofol (target-controlled infusion aiming at a plasma concentration of 2.0 micrograms ml-1). Myocardial blood flow was measured using a modified Kety-Schmidt technique. High-dose remifentanil anaesthesia significantly reduced cardiac index (CI) (-25%) as a consequence of a decrease in stroke volume index (SVI) (-14%) and heart rate (-13%). Mean arterial pressure (MAP) was 30% lower than that in the awake patient. Myocardial blood flow and myocardial oxygen uptake (MVO2) decreased by 30% and 42%, respectively. In contrast to high-dose remifentanil anaesthesia, systemic vascular resistance index (-14%) during remifentanil/propofol anaesthesia was significantly lower than that in the awake patient. Other haemodynamic variables, and myocardial blood flow and MVO2, did not significantly differ from the high-dose remifentanil period. In conclusion, high-dose remifentanil reduces SVI, heart rate, MAP, myocardial blood flow and MVO2 and its effects do not differ from those of remifentanil/propofol anaesthesia.

Aged↗

PubMed2000

Intraoperative acute occlusion of aortic bifurcation during extracorporeal circulation.

A 36-year-old male patient showed a significant decrease of arterial pressure in the lower extremities during coronary artery bypass grafting (CABG) with extracorporeal circulation (ECC). Arterial pressure measured in the femoral artery fell to 10-20 mmHg at the end of ECC, whereas in the upper extremities arterial pressure levels were normal. At the end of the surgery a complete ischemia of both lower extremities was observed. We suspected Leriche's syndrome and performed a successful aortic embolectomy through bilateral femoral arteriotomies immediately. An insufficient anticoagulation could be excluded by prolonged "activated clotting time" (ACT), therefore we presumed that the source of embolus was a small aneurysm of the left ventricle. The shape and superficial structure of the extracted embolus, which was partly covered with endocardium, confirmed our suspicion. No complications occurred throughout the postoperative period. On the 10th postoperative day, the patient left our department for postoperative rehabilitation with a normal perfusion of the lower extremities.

Adult↗