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Biomedical subjects

W Sandmann

Publications and source records attributed to W Sandmann.

At least 109 records · Page 6Linked to original sources
PubMed1991

Influence of SIMV plus inspiratory pressure support on VA/Q distributions during postoperative weaning.

Since the introduction of synchronized intermittent mandatory ventilation (SIMV) several advantages have been attributed to this ventilatory mode, one of them being a more homogeneous distribution of ventilation and perfusion than during controlled mechanical ventilation (CMV). Up to now no data are available to confirm whether this is true when SIMV is used in combination with inspiratory pressure support (IPS). Therefore, we compared the influence of CMV and SIMV + IPS on the distributions of ventilation and perfusion in 9 patients undergoing weaning from postoperative mechanical ventilation. Continuous distributions of ventilation and perfusion were assessed using the multiple inert gas elimination technique (MIGET). SIMV + IPS did not induce any change in the hemodynamic or oxygenation parameters, in particular CI and PaO2 remained constant. Physiological dead space (VD/VT) increased, but PaCO2 remained unchanged due to increased minute ventilation (from 9.5 +/- 0.9 l.min-1 to 11.3 #/- 1.2 l.min-1). The perfusion distributions remained unaltered; there was no change in QS/QT nor in the perfusion of the low VA/Q lung regions. This result was underscored by the unchanged dispersion of the perfusion distribution (log SDQ). The increased VD/VT was caused by increased inert gas dead space (from 22.0 +/- 9.6 to 26.8 +/- 8.7%) which was accompanied by increased ventilation of lung regions with high VA/Q ratios (10 less than VA/Q less than 100) in 3 patients. These results show that in our group of patients partial removal of CMV together with pressure support assistance of spontaneous ventilation did not induce a clinically significant loss of the efficiency of the breathing pattern.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Doppler colour flow imaging after carotid endarterectomy.

Sixty-six patients (72 carotid arteries) were examined after carotid endarterectomy (CEA) using Doppler colour flow imaging (DCFI). Examinations were performed 4-18 days (mean: 7 days) after surgery (32 patients, 34 arteries) or between 2 and 100 months (mean: 39 months) after CEA (34 patients, 38 arteries). Minor vessel wall abnormalities were found in 36% in the internal carotid artery (ICA) and in 55% in the common carotid artery (CCA) or bifurcation. One patient had a minor residual ICA stenosis after surgery; two low-grade stenoses and three ICA-occlusions were diagnosed at follow-up. Altered flow patterns occurred most in CCA (90%) and were predominantly located adjacent to the vessel wall and in dilated vascular segments of the CCA. Disturbed haemodynamics in the ICA were less marked (57%) and frequently found in the central vessel lumen or diffusely distributed. We conclude that surgically induced changes of the vessel geometry and residual or recurrent vascular wall abnormalities are often associated with distinct haemodynamic disturbances, which can reliably be detected by DCFI.

Blood Flow Velocity↗
PubMed1991

Right ventricular function assessed by thermodilution technique during apnea and mechanical ventilation.

OBJECTIVES: To evaluate strategies for thermodilution-based measurement of cardiac output and right ventricular (RV) ejection fraction and to assess the effects of controlled mechanical ventilation in patients. Furthermore, to compare strategy-associated reproducibility with reference values obtained during long-term apnea. DESIGN: Crossover trial in patients; reference values from apneic animals. SETTING: University ICU and physiology laboratory. PATIENTS: Six consecutive male ICU patients (48 to 70 yrs) after major abdominal vascular surgery. ANIMALS: two adult female sheep. INTERVENTIONS: Three ventilatory rates (8, 16, and 24 cycles/min) and 15-sec periods of apnea were selected for measurements in patients. In animals, continuous apnea was achieved with extracorporeal CO2 removal and apneic oxygenation. MEASUREMENTS: Measurements were performed using an appropriate pulmonary artery catheter and an ejection fraction/cardiac output computer prototype. The thermal indicator was injected automatically at four defined points of the ventilatory cycle, but triggered manually during apnea. MAIN RESULTS: At 8 cycles/min, there was a wide mean range of cyclic variable modulation, with a coefficient of variation of 11.6% and 23.2% for cardiac output and RV ejection fraction, respectively. Allowing for ventilatory phase or changing from 8 to 16 cycles/min reduced errors by half. Combining both procedures resulted in a coefficient of variation of 4.7% and 6.6% for cardiac output and RV ejection fraction, respectively. The best coefficient of variation values obtained during 15 secs of apnea in patients approached those variations in experimental apnea (coefficient of variation of 2.1% and 4.5% for cardiac output and RV ejection fraction, respectively). CONCLUSIONS: At low ventilatory rates, best results are achieved by averaging four phase-selected measurements. One-point measurements were less accurate and random point measurements less reproducible.

Aged↗
PubMed1990

[Surgical therapy of acute and embolizing deep venous thrombosis--indication, technical principle, results].

Between 1977 and 1986, 185 patients with deep venous thrombosis (117 with acute occlusive and 68 with embolizing deep venous thrombosis) underwent venous thrombectomy with arterio-venous fistula. The early patency rate was 96%, and the perioperative mortality rate, 3.8%. Of the 157 patients in whom extremities were involved, 147 were examined 12-118 months postoperatively (mean 43 +/- 23 months) clinically, by Doppler ultrasound and by light reflexion rheography (LRR). In 49% of the patients, various kinds of swelling or oedema of the involved extremities were present. There were no hemodynamical disturbances in 53% (LRR-examination); competent venous valves were found in 44%. According to the severity of symptoms and hemodynamical findings, postthrombotic syndrome was absent in 47%, mild in 20%, moderate in 28%, and severe in 5% (7 patients, 4 with venous ulcers). Six of the 7 patients with severe postthrombotic syndrome belonged to the group operated for embolizing thrombosis, where no selection of cases was performed. The best long-term results were achieved in patients operated for acute occlusive thrombosis of the iliac and iliofemoral veins. Venous thrombectomy with av fistula can achieve sufficient early and long-term results in the treatment of deep venous thrombosis, provided strict selection of patients and a meticulous technique are practised.

Adolescent↗
PubMed1990

[Transmetatarsal border zone amputation in arterial blood supply disorders].

Transmetatarsal amputations (TA) were performed in 32 patients (22 men, 10 women; mean age 64 [40-91] years) with occlusive arterial disease. Previous revascularization procedures (bypass, thrombendarterectomy, embolectomy) had been performed in 26 patients. Surgical results of TA after one year were good in 16, satisfactory in seven, and unsatisfactory in nine. Further amputations became necessary after a mean of 52 (4-221) days in four of the six patients without and five of 26 with previous revascularization. Follow-up examination 1-6 years after discharge found that six had died, 16 were able to walk and fully rehabilitated, while in ten walking was limited and they required help in walking.

Adult↗
PubMed1990

Does prostaglandin E1 and superoxide dismutase prevent ischaemic spinal cord injury after thoracic aortic cross-clamping?

The beneficial use of prostaglandin E1 (PGE1) and superoxide dismutase (SOD) on the tolerance to ischaemia of the spinal cord was evaluated following thoracic aortic cross-clamping in dogs. Aside from spinally evoked somatosensory potential (SEP) by means of a bipolar epidural catheter, postoperative evaluation of motor deficits was used to determine the efficiency of pharmacological protection when compared with controls. The animals were divided into four groups. Group I (n = 12) served as controls. The dogs of Group II (n = 12) were treated with PGE1 (100 ng/kg/min) during clamping and the first hour after declamping. In the third group (n = 12) SOD was given as an intra-arterial bolus (1 mg/kg) prior to declamping which was followed by a continuous perfusion (0.4 mg/kg/min) into the carotid artery for 25 min. In Group IV (n = 12) the dogs were treated with a combination of PGE1 and SOD in the same manner as in Groups 3 and 4. Results after pharmacological protection were significantly better than controls. In Group I all animals but one (92%) were paraplegic, as were five in Group II (42%) and eight in Group III (67%). In contrast no dog in Group IV developed paraplegia. There was a close correlation of SEP and postoperative recovery. The group with combination therapy (PGE1 plus SOD) was characterised by a loss of the evoked potential for a mean of 15 min, the PGE1 group for 45.8 min and the SOD group for 58.5 min. While the control group was characterised by a loss of 72.7 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Alprostadil↗
PubMed1990

Results of surgical treatment for atherosclerotic renovascular occlusive disease.

In this study we retrospectively examined the results of surgery for atherosclerotic renal artery lesions and analysed the factors that may affect postoperative blood pressure response, changes in renal function and late mortality. A total of 326 patients were operated on over a 15 year period and were followed up for periods from 4 to 165 months (mean follow-up time: 37.2 months). An extra renal vascular area was also involved in 91.4% of cases and in 187 (57.3%) a significant involvement of both renal arteries was found and simultaneously treated. Combined revascularisation of other arteries was performed in 50.3% of patients. The indications for surgery were the treatment of extreme hypertension in 243 patients (74.5%), the improvement of renal function in 45 with renal insufficiency, and preservation of the kidney in 38 (11.7%). The preferred method of reconstruction was transaortic endarterectomy (236 cases, i.e. 72.4%) and postoperative angiography demonstrated a normal patent renal artery in 319 of 338 studied renal arteries (94.4%). There were no deaths in the early postoperative period after isolated renal artery reconstruction. Of the 164 patients with simultaneous renal and aortic reconstruction however 14 died during the early postoperative phase. The overall early mortality was thus 4.3% (14 out of 326 patients) and correlated significantly with the extent of the atherosclerotic disease, the age of the patients, the operative technique used and the different intra- and postoperative management during the two different periods of our experience (1974-1980 v. 1981-1989).(ABSTRACT TRUNCATED AT 250 WORDS)

Arteriosclerosis↗
PubMed1990

["Inflammatory aneurysm" of the aorta. Diagnosis, therapy, results].

From 1970 to 1987 among 964 patients with aortic aneurysms 52 (5.4%) underwent aortic graft replacement for inflammatory aortic aneurysm. 79.2% were symptomatic, 18.9% ruptured at the time of admission. CT-scan is of main diagnostic value. The perioperative mortality rate was 15.1%. At follow-up (28 months mean) 35 of 38 living patients (92.7%) were examined clinically, by sonography and in most cases by CT-scan. The late complication rate was 20% (n = 7, atrophic kidney 3, anastomotic aneurysms 4). In contrast to abdominal aortic aneurysms inflammatory aneurysms present an elevated morbidity and mortality rate which has to be reduced by exact preoperative diagnosis and modified surgical technique.

Aged↗
PubMed1990

[Results of therapy following lumbar sympathectomy. A retrospective study over the course of 10 years].

In a retrospective study we report about 142 patients who had 159 lumbar sympathectomies from 1975-1985. The angiological status was evaluated with a clinical examination or a questionnaire. In 96% we saw the clinical stages III and IV. The clinic lethality was 3.5%. Besides the sympathectomies 62 reconstructive procedures were necessary which were performed mostly before the sympathectomy. The higher the occlusion resp. stenosis the worse the prognosis after sympathectomy. A postoperative abstinence of smoking improves the prognosis. The amputation rate was 35.8% including minor amputations (n = 20) and loss of the extremity (n = 37). The high number of minor amputations shows that the sympathectomy is an appropriate procedure to shift the amputation to the periphery. The older the patient the higher the amputation rate. The analysis of the clinical examination or the questionnaire shows that a third of the patients has a long-term profit from the sympathectomy.

Adult↗
PubMed1990

[Surgical treatment of peripheral arterial occlusive disease in diabetes mellitus; in situ saphenous vein bypass versus reverse bypass procedure--a retrospective study].

The scope of reconstructive possibilities in the treatment of patients with peripheral occlusive arterial disease and diabetes mellitus had been increased thanks to further development of surgical methods. It is especially the in-situ-bypass procedure which has opened the path to new anastomotic sites at the level of the foot. Our own experience with 86 bypass procedures in 84 patients has given us an early patency rate of 82% in non-diabetic arterial occlusions and of 80% in diabetics. The amputation rate was 7% in the former group, 14% in diabetics with atherosclerotic occlusion. In comparison to the reversed bypass the early graft occlusion rate fell from 26% to 14% and the amputation rate from 13 to 9%. Thus, operative mortality fell from 9 to 2.4%, although the average age had risen from 61 to 67 years and the percentage of stage IV disease from 38% to 51%. Patency of bypass procedures with anastomosis to distal calf arteries was 83% und rose to 92% if the distal anastomosis was to arteries in the vicinity of the ankle. The caveat in this study is the fact that an apparent superiority of the in-situ-bypass is based on retrospective comparison of somewhat widely separated historical groups.

Aged↗