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W Sandmann

Publications and source records attributed to W Sandmann.

At least 91 records · Page 5Linked to original sources
PubMed1993

Use of the electrospinogram for predicting harmful spinal cord ischemia during repair of thoracic or thoracoabdominal aortic aneurysms.

BACKGROUND: To reduce the incidence of misleading assessments, and to derive criteria for critical spinal cord ischemia during thoracic or thoracoabdominal aortic aneurysm repair, the authors epidurally stimulated and recorded somatosensory evoked potentials (ESEP) below and above, respectively, the spinal segment at risk (electrospinogram). METHODS: Epidural somatosensory evoked potentials were analyzed in 100 consecutive patients undergoing resection of aortic aneurysms using two bipolar catheters (stimulation at the L2 level and recording at the T3 level) for the following criteria: 1) the time until ESEP disappeared completely after cross clamping, 2) the duration of complete ESEP loss during and after cross clamping, and 3) the time until ESEP recovered after declamping. Postoperatively, neurologic deficits were evaluated by a neurologist who was unaware of the ESEP recordings. RESULTS: Three types of patients could be identified. First, thirty-one patients neither showed ESEP loss nor neurologic deficits. Second, ESEP loss occurring later than 15 min after cross clamping was associated with a neurologic deficit in 2 of 29 patients (6.9%). And, third, 12 of 40 patients (30%) presented a neurologic deficit when ESEP loss occurred within 15 min after cross clamping. Further indicators of an impending risk were a total ESEP loss greater than 40 min (sensitivity 100%, specificity 68%, positive predictive value [PPV] 35%, and negative predictive value [NPV] 100%), and a recovery of ESEP later than 20 min after declamping (sensitivity 93%, specificity 86%, PPV 52%, and NPV 99%). CONCLUSIONS: Epidural somatosensory evoked potentials appeared to be a reasonable intraoperative predictor of postoperative neurologic outcome, and informs surgeons and anesthesiologists about the impending danger at an early state of the operation.

Adult↗
PubMed1993

[Prevention of acute renal failure in suprarenal aortic surgery. Results of a pilot study].

Acute renal failure continues to be a frequent complication after vascular operations with interruption of renal circulation. Aim of the study was to evaluate two methods to prevent postischemic renal failure after suprarenal aortic surgery: the pretreatment with Prostaglandin E1 and the organ perfusion with cold saline solution. 24 patients, who did not receive Prostaglandin E1 or cold organ perfusion were used as control (Group A). 37.5% of these patients (n = 9/24) developed acute renal failure. 3 needed hemodialysis postoperatively. Only 3 out of 26 patients (11.5%), who received PGE1 (Group B), showed deterioration of renal function with plasma creatinine values greater than 2 mg % and no patient needed dialysis. 6 out of 26 patients (23%), who received organ perfusion with cold saline (Group C), developed acute renal failure and in one case temporary hemodialysis was necessary. Plasma creatinine increased in the group A from 1.1 (0.1) mg % to 1.95 (0.4) mg % on third postoperative day and to 2.1 (0.4) mg % on discharge, while after pretreatment with PGE1 (Group B) plasma creatinine increased from 1.25 (0.1) mg % to 1.44 (0.1) mg %. In the group C creatinine increased from 1.3 (0.1) mg % to 1.77 (0.1) mg %. On discharge from the hospital plasma creatinine decreased to mean values of 1.25 (0.1) mg % in the group B and 1.5 (0.1) mg % in the group C. Intraoperative organ perfusion with cold saline and Prostaglandin E1 allows today complicated arterial reconstructions of both aorta and renal arteries with minimal risk of postischemic renal damage.

Acute Kidney Injury↗
PubMed1993

[The role of pharmacologic kidney protection in preventing post-ischemic renal failure in animal experiment].

The postischemic acute renal failure is one of the most important and frequent complications after surgery for renal artery and thoracoabdominal aortic diseases. In a canine model we studied the possible beneficial effects of Prostaglandin E1 (PGE1), Diltiazem and Superoxiddismutase (SOD) on postischemic renal function. 46 dogs were exposed to 3 hours ischemia. In 35 dogs PGE1 (n = 10), Diltiazem (n = 10), Superoxiddismutase (n = 10) or both PGE1 and SOD (n = 5) were given intravenously. 11 dogs treated with normal saline served as controls. Glomerular filtration rate, renal plasma flow, plasma creatinine, blood urea nitrogen, urine volume, free water clearance and renovascular resistance were calculated before and after renal ischemia. Radionuclide studies were performed on the third postoperative day. Two weeks later clearance measurements were repeated and kidneys were removed for histology. PGE1, Diltiazem and SOD significantly attenuated the post-ischemic fall in glomerular filtration rate and renal concentrating ability as well as the postischemic changes of tubular epithelium on histology.

Acute Kidney Injury↗
PubMed1992

In situ and composite in situ vein bypass for upper extremity ischaemia.

The in situ saphenous vein bypass for lower limb revascularisation is well established. For upper extremity ischaemia necessitating bypass this special technique offers the same advantages. From 1987 to 1991 five patients underwent cephalic and basilic vein in situ bypass for critical ischaemia of the upper extremity. Underlying disease was a thoracic outlet syndrome (two cases), radiation injury (one case) and a chronic atherosclerotic lesion (two cases). One graft failed because of a critical outflow situation. The most important advantage of the in situ technique for revascularisation of the upper extremity seems to be minimal endothelial damage and the better compliance of the in situ vein to the extensive movements of the joints.

Aged↗
PubMed1992

Isoflurane does not increase the incidence of intraoperative myocardial ischaemia compared with halothane during vascular surgery.

We have studied the incidence of new intraoperative myocardial ischaemia (IMI), myocardial infarction (MI) and cardiac death (CD) in 500 consecutive patients undergoing elective major non-cardiac vascular surgery. Patients were allocated randomly to receive either halothane (n = 226) or isoflurane (n = 274) as principal anaesthetic agent. Using real-time ST segment trend analysis (leads V5 and II) IMI (halothane 39%, isoflurane 38%), MI (halothane 1.3%, isoflurane 1.5%) and CD (halothane 0.4%, isoflurane 0.7%) did not differ significantly between the two groups. Twenty-three per cent of IMI episodes were related to haemodynamic disturbances, but unrelated to the type of surgery: 148 supra-aortic (IMI = 39%), 244 abdominal aortic (IMI = 41%) and 108 lower extremity revascularizations (IMI = 33%). We conclude that the choice of volatile anaesthetic agent does not influence cardiac morbidity or mortality in this type of patient.

Adult↗
PubMed1992

[Spontaneous renal artery dissection].

The clinical clues of sudden arterial hypertension, acute pain in the side, proteinuria, hematuria, abdominal bruits and renal failure are suspicious for spontaneous dissection of the renal arteries, even in the absence of one or more of the above-mentioned symptoms. To confirm the diagnosis and to provide appropriate therapy, immediate renal arteriography is mandatory, otherwise acute loss of renal tissue may occur. We report on one patient with spontaneous dissection of the renal arteries.

Aortic Dissection↗
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↗