Biomedical subjects

A Scherhag

Publications and source records attributed to A Scherhag.

17 recordsLinked to original sources

PubMed2006

Proven strategies to reduce cardiovascular mortality in hemodialysis patients.

BACKGROUND: In hemodialysis patients, left ventricular hypertrophy (LVH) correlates with mortality. The reason for LVH in uremics is multifactorial. The primary objective of our study was to investigate the effects of a multi-interventional treatment strategy on LVH. METHODS: In 230 ambulatory patients, including patients with coronary artery disease, diabetes, diastolic and systolic dysfunction, we continued optimized cardiac therapy (beta-blockers, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers) with full anemia correction by intravenous epoetin-beta. The dose of epoetin-beta for maintaining target hemoglobin (Hb) was 68 +/- 23 IU/kg/week. Serial echocardiograms were recorded every 3-6 months. The mean observation period was 4.8 +/- 1.2 years. RESULTS: Mean Hb at baseline was 11.2 +/- 2.0 versus 14.1 +/- 1.4 g/dl (p < 0.001) at study end. There was a significant reduction in left ventricular mass index (LVMI: 159 +/- 50.4 vs. 130.2 +/- 42.7 g/m(2); p < 0.001). In a subgroup of 2/3 of the patients, LVMI returned to normal (169 +/- 33 vs. 114 +/- 14 g/m2; p < 0.001). CONCLUSION: Baseline LVMI (p < 0.001), Hb increase (p < 0.03), and triple cardiac therapy (p < 0.03) were significant and independent prognostic factors for a reduction in LVMI. The annual cardiovascular mortality was 5%. Even anemia correction from 12 to 14 g/dl results in further (p < 0.001) regression of LVMI.

Aged↗

PubMed2005

Diagnostic value of stress echocardiography for the detection of restenosis after PTCA.

Stress echocardiography (SE) has become a widely accepted clinical tool for the non-invasive diagnosis of coronary artery disease (CAD). Previous studies have confirmed that SE has superior diagnostic value compared to exercise ECG testing. SE has also emerged as a cost-effective alternative to nuclear imaging techniques in patients where symptoms and/or conventional ECG stress testing have provided ambiguous results. Several studies have investigated the value of SE to detect significant restenosis after PTCA. However, in these studies, different methods have been used to induce cardiovascular stress such as physical exercise by bicycle or treadmill, pharmacologic stress testing (with dipyridamole or dobutamine) or transoesphageal atrial pacing. This review evaluates the published database of SE to detect restenosis in patients after successful PTCA. It includes 13 studies with a total of 989 patients performed at 3-6 months after the primary intervention. The diagnostic value, utility and limitations of SE is presented and discussed. The data show that SE has a high diagnostic value for detecting significant restenosis after PTCA. Mean sensitivity of SE was 74% (CI 69-79%), mean specificity was 87% (CI 84-89%). The positive predictive value (PPV) of SE was 83%, the overall negative predictive value (NPV) 97%. We conclude that, in the follow-up of patients after PTCA, SE has distinct advantages over other non-invasive methods and is a recommended method for the detection of those to be considered for repeat angiography.

Angioplasty, Balloon, Coronary↗

PubMed2005

Automated impedance cardiography for detecting ischemic left ventricular dysfunction during exercise testing.

UNLABELLED: Automated impedance cardiography (ICG) is an attractive method for noninvasive hemodynamic evaluation. The objective of our study was to evaluate the feasibility and diagnostic value automated ICG in patients with suspected coronary artery disease (CAD). We measured stroke index (SI) and cardiac index (CI) in 65 patients with suspected CAD at rest and during bicycle exercise testing. All patients underwent subsequent cardiac catheterization including coronary angiography (CA). Depending on the results of CA, patients were divided into three groups, patients without significant CAD (group 0), single vessel disease (group 1) or multivessel disease (group 2-3). In a subset of 20 patients, automated ICG was compared to measurements of CI by the thermodilution (TD) method. RESULTS: There were no significant differences in SI and CI at baseline between the three groups. At 75- and 100-watt exercise, patients in group 2-3 showed significantly lower mean values of SI and CI as compared to patients of group 0 and group 1 (all p < 0.05), indicating exercise-induced ischaemic left ventricular (LV) dysfunction. Three patients had to be excluded because of inappropriate quality of the ICG signals during exercise. Comparison of automated ICG with TD measurements of CI showed good correlations between both methods at rest (r = 0.73) and during exercise (r = 0.89-0.91). CONCLUSIONS: We conclude that hemodynamic monitoring by automated ICG is both feasible and practical during exercise testing. Automated ICG can provide reliable and valuable additional diagnostic information on LV function during exercise which is helpful for selecting those patients for angiography who are likely to benefit from coronary interventions.

Adult↗

PubMed2005

Comparison of impedance cardiography and thermodilution-derived measurements of stroke volume and cardiac output at rest and during exercise testing.

BACKGROUND: Non-invasive evaluation of haemodynamic variables remains a preferable and attractive option in both pharmacologic research and clinical cardiology. OBJECTIVES: The objective of this study was to evaluate the correlation, feasibility and diagnostic value of haemodynamic measurements by ICG with the thermodilution (TD) method at rest and during exercise testing. METHODS: We measured stroke volume (SV) and cardiac output (CO) with both methods in 20 patients with suspected coronary artery disease (CAD). All measurements were performed simultaneously at rest and during bicycle exercise. RESULTS: There was a highly significant correlation (p < 0.001) for measurements of SV between both methods at rest (r = 0.83) and during exercise (r = 0.85-0.87) with 50-100 watts. For measurements of CO, the respective correlations were r = 0.85 at rest and r = 0.92-0.94 during exercise. The mean difference for measurements of SV were 3.8 +/- 12.6 ml at rest and 6.5+/- 11.4 ml during exercise. For measurements of CO, the mean difference between both methods was 0.9 +/- 1.0 l/min at rest and 1.0+/- 0.8 l/min during exercise. Compared to TD measurements, ICG had a bias to overestimate SV and CO of approximately by 5-10%. One patient had to be excluded because of inappropriate quality of the ICG signals during exercise. CONCLUSIONS: ICG is a feasible and accurate method for non-invasive measurements of SV and CO. Haemodynamic measurements by ICG were correlated highly significant to simultaneous measurements by the TD method.

Aged↗

PubMed2001

Haemodynamic quantification of different provocation manoeuvres by simultaneous measurement of right and left atrial pressure: implications for the echocardiographic detection of persistent foramen ovale.

AIMS: Persistent foramen ovale (PFO) is found in 9.2--32% of echocardiographic examinations. The gold standard for the detection of a PFO is transoesophageal echocardiography (TEE) and the mostly used provocation test is the Valsalva manoeuvre. The aim of our study was to evaluate the effectiveness of the Valsalva manoeuvre compared to other provocation tests by simultaneous haemodynamic measurements of the right and left atrial pressure. METHODS: Fifty patients underwent Swan-Ganz catheterization. Right atrial pressure and pulmonary capillary wedge pressure, which corresponds to the left atrial pressure, were measured simultaneously. The following manoeuvres were compared: the Valsalva manoeuvre, coughing, deep inspiration and expiration pressures of 20 mmHg, 40 mmHg and 60 mmHg. The main objective of our study was to compare the occurrence of pressure gradients (right atrial pressure> left atrial pressure). For further quantification mean gradients, time duration of pressure overlap, as well as products of mean gradients and overlap time were analysed. RESULTS: During the Valsalva manoeuvre a significant pressure gradient could be observed in 84% of the patients, followed by an expiration pressure of 60 mmHg (82%), inspiration (78%), expiration pressure of 40 mmHg (76%), coughing (75%) and an expiration pressure of 20 mmHg (62%). Comparing the mean gradients and the products of mean gradients and overlap time duration during the different manoeuvres, we could detect the significantly best results with the Valsalva manoeuvre. CONCLUSIONS: The Valsalva manoeuvre might be the most effective test to provoke a right-to-left atrial shunt for the detection of a PFO during echocardiographic examinations.

Adult↗

PubMed2000

[Self-expanding nitinol stents in proximal tracheal stenosis].

UNLABELLED: The use of silicone- or metal stents in stenosis of the distal trachea and the bronchial system is a customary procedure [1-4], for example after tumor invasion or cicatricial stenosis after transplantation. In the proximal part of the trachea, on smaller, short and soft strictures we try to stabilise the trachea by the implantation of rings. Other methods are tracheal plasty or transverse tracheal resectomy [5-7]. In the case of longer or nearer subglottal stenoses the positioning of self-expanding nitinol stents has proven a simple, gentle and well-tolerated alternative procedure even in very serious disorders [1, 8, 9]. METHOD: These stents can be placed in short narcosis under endoscopic control without great strain on the patient. RESULTS: We placed nitinol-stents in the proximal part of the trachea in eleven cases. In five cases dyspnoea caused by a tracheal collapse improved. In two further cases a tracheal stenosis with massive granulation tissue and cicatricial pull under an inlaid tracheal cannula was removed and the tracheostoma was closed. In four cases a solid, scarred and cartilaginous stenosis in the area of the cricoid and the upper tracheal rings was widened with laser and later on stented. CONCLUSION: Over an observation time of two years no complications showed safe one case in which a directly postoperative dislocation was repositioned quickly. The patients live without restrictions through the tracheal stenosis or a tracheostoma. In the best possible case epithelialization over the metal meshes develops so that a nearly normal mucus transportation is possible [1, 10-12].

Adult↗

PubMed2000

[Analgosedation (managed anesthesia care--MAC) with propofol and piritramide for controlled cyclophotocoagulation of the eye].

The new method of controlled cyclophotocoagulation of the eye is an example of a short, non-invasive procedure that is still too painful to be done under local anaesthesia alone. The risks associated with general anaesthesia, on the other hand, seem to be inappropriately high compared to the risks associated with the procedure itself. Therefore, for this procedure, we combined local anaesthesia with 0.5% proxymetacain and 10% cocaine and sedation with propofol and analgesia with piritramide. Our experiences with this method have been positive. We have applied our method to 42 patients undergoing a total of 53 procedures and we have seen no major changes in haemodynamics and only two cases of momentary slight ventilatory depression. Therefore, we conclude that our method of managed anaesthesia care is suitable for patients undergoing cyclophotocoagulation of the eye, combining patient comfort with haemodynamic stability and minimal risk for the patient.

Adult↗

PubMed1999

Short term cardiovascular effects of aldosterone in healthy male volunteers.

Clinical evidence of rapid, nongenomic aldosterone effects in the cardiovascular system has been provided by clinical studies; an increase in systemic vascular resistance (SVR) was shown by invasive techniques within 3 min after injection of aldosterone. Here, we study the dose dependency and the later course of the rapid aldosterone effects by noninvasive techniques. In 12 healthy male volunteers, SVR and heart rate variability were determined by impedance cardiography and digital electrocardiography, respectively, for 8 h after the injection of 0.05 or 0.5 mg aldosterone in a double blind, placebo-controlled, 3-fold cross-over study. No significant differences were observed for baseline values among the three treatments. The area under the curve of SVR during the first 45 min after injection was significantly different between the periods with the highest areas under the curve seen after the injection of 0.5 mg aldosterone (mean +/- SD, 40.4 +/- 12.8 vs. 36.8 +/- 10.3 for 0.05 mg aldosterone and 36.8 +/- 10.4 for placebo; P = 0.05). Individual comparisons showed significant differences at 6 and 30 min between placebo and the 0.5 mg aldosterone period (P < 0.05), with values for the 0.05 mg aldosterone period similar to those for the placebo period. From 330-390 min, opposite changes occurred; SVR was depressed during the 0.05 mg (P < 0.05) and 0.5 mg aldosterone periods compared with that during the placebo period. These delayed effects may reflect an increased vagal tone in the aldosterone groups, as demonstrated by higher values of the time domain parameter of heart rate variability pNN50. This study provides further evidence for clinically detectable rapid cardiovascular aldosterone effects in vivo obtained by noninvasive techniques. The data are consistent with the view of aldosterone as a rapid modulator of cardiovascular responses acting through nongenomic mechanisms.

Adult↗

PubMed1999

[High-frequency jet ventilation for placing tracheal stents--a case report].

Stenoses of the larynx and trachea may cause acute life-threatening situations. Surgical procedures in patients presenting this type of problem are a real challenge for the surgeon and the anaesthesiologist. Depending on the extent and the nature of the stenosis, the insertion of a stent may be the best therapeutic option. In this case, the high frequency jet ventilation offers certain advantages for the surgeon. Thanks to modern jet ventilators with automatic pressure monitoring and jet ventilation tubes with a separate lumen for pressure monitoring, the danger of barotrauma is considerably reduced, even in patients with a high-degree stenosis of the larynx and trachea. During insertion of a tracheal stent during jet ventilation, the complete cross-section of the trachea must at least be temporarily available to the surgeon. In addition, at the end of the operation the newly implanted stent should not be altered by manipulations necessary for artificial respiration. We describe a new method which uses tracheal jet ventilation for implanting a stent with only short interruptions of artificial ventilation. During recovery from anaesthesia, there is no risk of dislocating the newly placed stent.

Carcinoma, Adenoid Cystic↗

PubMed1998

[Plasma concentrations of bupivacaine for continuous peridural anesthesia in children].

Epidural anaesthesia is extremely useful in providing postoperative analgesia for children after surgery of the lower body. Although results on early pharmacokinetics in children have previously been reported, no data are available on the long-term effects of epidural anaesthesia. The aim of this investigation was the assessment of plasma bupivacaine levels in children with continuous epidural anaesthesia in the postoperative period. A catheter with an outer diameter of 0.63 mm was inserted through a 19G Tuohy cannula into the epidural space. A maximum dose of 0.4 mg/kg/h bupivacaine was administered for continuous epidural infusion. Careful monitoring was performed to detect early signs of local anaesthetic intoxication. Two milliliters of blood were obtained in each patient per day and nepholometric serum measurement were performed to determine alpha 1-acid glycoprotein and albumin levels. Bupivacaine plasma concentrations were assessed according to the method described by Sattler et al. [25]. Ten children were included in the investigation. The measured albumin and alpha 1-acid glycoprotein concentrations were within the range described by other investigators. At the onset of pain therapy maximum levels of 0.5 microgram/ml were recorded after a loading dose of bupivacaine and levels of up to 2.2 micrograms/ml were achieved following continuous infusion. There were no neurologic complications or signs of local anesthetic intoxication. In conclusion our results show that a dose of up to 0.4 mg/kg/h bupivacaine during continuous epidural infusion is not associated with toxic complications. Careful monitoring of the children by experienced staff is mandatory.

Anesthesia, Epidural↗

PubMed1998

[Special aspects of anesthesia in patients with epidermolysis bullosa based on a case example].

Epidermolysis bullosa hereditaria dystrophica (Hallopeau-Siemens) is a rare autosomal recessive disease characterized by extreme bullae formation of skin and mucosa. Typical dystrophic nails and flexion contractures of the joints can lead to deformities. Carious teeth and microstomia caused by scarred contractures of the lips are characteristic of the clinical picture. Depending on the form and severity of epidermolysis bullosa, the anaesthetic and surgical management requires careful planning to avoid unnecessary complications as a result of positioning, anaesthesia or surgery. In cooperation with the patient, optimal positioning on the operating table without pressure or tangential friction of the skin needs to be achieved. Wherever possible, surgical tape and adhesive electrodes should be avoided. Artificial respiration, intubation and monitoring must be adapted to the skin conditions of the patient. In particular the skin below the blood pressure cuff must be protected by adequate padding, and maximum intervals between measurements should be chosen. Nasal, oral, laryngeal and tracheal manipulations should be kept to a minimum for protection of the upper airway. Fibre optic intubation is to be preferred because of the possibility of microstomia and the need for simultaneous airway diagnosis. In addition, oro- or nasopharyngeal tubes and catheters should be avoided where possible. Depending on the course of surgery and anaesthesia, postoperative therapy in an intensive care unit should be considered.

Adult↗

PubMed1996

[Value of dipyridamole-atropine stress echocardiography for detection of patients with restenosis after PTCA].

UNLABELLED: Stress-Echocardiography has been proven to be a valuable method in the diagnosis of patients with suspected coronary artery disease. It has been demonstrated that the addition of atropine can increase the sensitivity of pharmacological stress-echocardiography-tests. The aim of our study was to evaluate the diagnostic potential of dipyridamole-atropine-echocardiography for the detection of restenosis after coronary angioplasty. We investigated 50 patients 3-6 months after primary successful coronary angioplasty. Restenosis was defined as recurrence of stenosis of > or = 70% at the site of dilatation determined by quantitative coronary angiography. All patients were investigated on antianginal medication and underwent control-coronary angiography within 1-3 days after the echocardiographic study. In 17/23 patients with restenosis, the dipyridamole-atropine-stress-test was pathologic (sensitivity 74%), in 25/27 patients without significant restenosis the echocardiography stress-test was normal (specificity 93%). In 6 patients with restenosis and an unsuspicious stress-test, the percent diameter of restenosis did not exceed > or = 90% lumen narrowing, restenosis of the LAD was correctly identified in all patients (n = 11). The diagnostic accuracy of the dipyridamole-atropine-stress-test for the detection of patients with restenosis after PTCA in our study was 84%, the positive predictive value of a pathologic echocardiography stress-test for the detection of significant restenosis was 89%, the negative predictive value was 81%. CONCLUSIONS: Dipyridamole-atropine-echocardiography has diagnostic potential for non-invasive assessment of patients after coronary angioplasty. In patients with a normal echocardiographic stress-test, the probability of significant restenosis is considerably low, even if restenosis cannot be definitely excluded.

Aged↗

PubMed1995

[Continuous breath alcohol analysis. Monitoring of irrigation absorption syndrome in transurethral prostate resection].

The absorption of large volumes of irrigation fluid is a major problem in transurethral prostatic surgery (TUR-P). Various indicators have been tested to monitor fluid absorption with regard to continuous registration and sufficient accuracy. The volumetric fluid balance is not suitable as a routine method because of its inaccuracy. Easily accessible parameters are unspecific because of surgical bleeding (haematocrit [Hct]), or are interfered with by physiological counter-regulatory actions (serum sodium [Na] concentration). In 1986 Hulten et al. suggested adding 2% ethanol to the irrigation fluid as a marker and investigated it intermittently in the expired air with an alcohol-test appliance. In a prospective clinical study of 17 patients undergoing TUR-P under spinal anaesthesia, expiratory concentrations of alcohol that was added to the irrigation fluid (2% ethanol in Purisole, Fresenius, Bad Homburg) were monitored. Gas was continuously sampled from the nasopharynx through a nasal cannula and the ethanol concentration was measured using a modified diverting anaesthetic gas monitor (Normac, Datex, Helsinki) that allows continuous as well as early detection of the absorbed irrigation fluid with reliable accuracy for clinical use. In addition, at intervals of 10 minutes we measured blood alcohol, end-tidal alcohol (Alcotest 7110, Dräger, Lübeck), haematocrit, serum Na concentration, and blood gases. Sixty-eight measurements were obtained from the 17 patients. As shown in other studies, serum Na (r2 = 0.68) and Hct (r2 = 0.39) correlated poorly with the irrigation fluid as determined by serum alcohol levels. In contrast, the expiratory alcohol measurements with the Alcotest 7110 (r2 = 0.93) and Normac devices (r2 = 0.85) were closely related. Continuous monitoring of the expiratory alcohol concentration with a Normac monitor closely reflects blood alcohol concentration, and may hence serve as a useful semiquantitative monitor of irrigation fluid absorption during TUR-P.

Absorption↗

PubMed1994

[Control of the placement of central venous catheters using x-ray and sonographic methods. A comparative controlled study].

At present there is no method available meeting all demands for accurate, simple and non-invasive verification of the position of central venous catheters. Using sonographic methods, it should be possible to verify central venous catheters intracardially or in the superior vena cava. We investigated whether the sonographic imaging of central venous catheters using a mobile echo camera presented an alternative to the usual control method using fluoroscopy. Since the investigated method has a rate of 20 to 30% false positive results and 8 to 26% false-negative results, it cannot be used as a routine alternative to fluoroscopy.

Adult↗

PubMed1990

[A universally applicable mask attachment for fiberoptic intubation. The Mainz Universal Adapter].

The problems associated with "difficult airways" have almost subsided since the introduction of flexible fiberoptic bronchoscopes for tracheal intubation. Limitations of this technique persist with uncooperative patients, children and infants. We describe an universally applicable connector for fiberoptic intubation during mask ventilation, which fits all masks with a 22-mm connector, including the Rendell-Baker-Soucek type. This technique is of utmost value when a "difficult airway" is encountered only subsequent to induction of anesthesia, especially if nondepolarizing muscle relaxants have been administered. The device makes intubation possible with all sizes of fiberoptic bronchoscopes. The prerequisites for application of this technique include an airway that will be maintained by mask ventilation.

Adolescent↗

PubMed1989

[Cannulation of the internal jugular vein using 2 ultrasonic technics. A comparative controlled study].

The internal jugular vein (IJV) is a common access route to the central venous system. Anatomical landmarks (group I) are normally used for localization of the IJV. We have compared this method with two other methods based on ultrasonic waves to identify the IJV and the carotid artery (CA) (even in atypical positions). We employed an ultrasound Doppler device in group II and a real-time ultrasonograph in group III. Central venous catheters were placed into the right IJV by the Seldinger technique. The IJV could be located in all patients with both ultrasound methods, but the course of the IJV could only be identified by ultrasonography. For this reason, the direction of the IJV was classified as "typical" in 80% of group I, in 85% of group II, but in only 45% of group III. No intergroup differences were found with respect to the number of punctures (mean value 1.6 +/- 0.83) and the incidence of complications. The time required to locate the site and direction of puncture increased with technical sophistication. There was, however, no difference in the total time for catheter placement, because puncture was performed faster when aided by sonography. In four patients in groups I and II, in whom attempts to puncture the IJV had not been successful, this could subsequently be achieved with ultrasonographic aid. One patient (group I) displayed a hematoma following inadvertent puncture of the CA. In one patient in group II the IJV and CA could not be distinguished as one was overlying the other. The echocamera provided improved localization of the IJV and the CA in comparison with the Doppler ultrasound.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1987

[Catheterization of the internal jugular vein using sonography].

Localisation of the internal jugular vein (IJV) by anatomical landmarks is common clinical practice. Specific complications associated with this technique are documented. Cannulation of the IJV is likely to be safer, when performed under direct vision, provided by a sonographic device. Following sonographic visualization, we have cannulated the IJV of 50 patients without complications. The tested device (Echokamera SSD-210 DX combined with the small-part-transducer UST-558-5, 5 MHz, 34 mm) proved useful in facilitating IJV cannulation.

Catheterization, Central Venous↗