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Biomedical subjects

J Fichter

Publications and source records attributed to J Fichter.

At least 19 recordsLinked to original sources
PubMed1999

Clinical significance of sleep-related breathing disorders in patients with implantable cardioverter defibrillators.

The prevalence and clinical significance of sleep-related breathing disorders (SRBDs) in patients with cardiac disease and a history of life-threatening ventricular tachyarrhythmias is unclear. Forty consecutive recipients of implantable cardioverter defibrillators (ICDs) with cardiac disease and a documented history of spontaneous, life-threatening, ventricular tachyarrhythmias underwent full night polysomnography. SRBDs were diagnosed if the apnea/hypopnea index was > 10. SRBD were diagnosed in 16 of 40 patients (40%): central sleep apnea (CSA) was present in 9 of these 16 patients (56%), 8 of whom had associated Cheyne-Stoke respiration. Seven of the 16 patients with SRBD (44%) had obstructive sleep apnea (OSA). Patients with and without SRBDs were comparable with respect to left ventricular ejection fraction, NYHA classification, underlying heart disease, ICD indications, and concomitant antiarrhythmic drug and beta-blocker therapy. Patients were followed prospectively for 2 years. ICD-treated ventricular tachyarrhythmias occurred in 10 of 24 patients (42%) without SRBD, in 4 of 9 patients (44%) with CSA, and in 3 of 7 patients (44%) with OSA (NS). The numbers and circadian distributions of episodes recorded during follow-up in patients without SRBD versus with CSA or OSA were not significantly different (14 +/- 25, median = 4 vs 4 +/- 5, median = 2.5 vs 15 +/- 15, median = 7, respectively). The 2-year mortality, which was entirely attributable to nonsudden cardiac events, was highest in patients with CSA (4/9 [44%], vs 0/7 [0%] with OSA, vs 3/24 patients (12.5%) without SRBD; P < 0.05).

Aged↗
PubMed1999

[Effect of oxygen (FI02: 0.35) on the aerobic capacity in patients with COPD].

BACKGROUND: Disability in patients with chronic obstructive pulmonary disease has led to the development of rehabilitation programs to increase exercise tolerance. OBJECTIVE: To determine, if the effect of training can be improved by giving supplemental oxygen during exercise. MEASUREMENTS: Ten male patients with COPD (mean FEV1 = 43.2 +/- 17.1% pred) underwent a five day per week cycle ergometer training program for four weeks at least 45 minutes per day at a constant workload of 80% of their highest achieved workrate--measured in an incremental exercise test before training. At this workrate all patients performed exercise above their anaerobic threshold. Five patients were breathing 35% oxygen during exercise, five were breathing roomair (randomised, single blind). To evaluate and compare the results of training before and after the program all patients performed an incremental exercise test (continuously increasing workrate) with roomair. RESULTS: In the group breathing 35% O2 during training the maximally achieved power in the incremental exercise test after training was 15.9% higher. In the group breathing roomair during training the maximally achieved power after training was 36.3% higher than before (p < 0.05). This group also showed significant reductions in lactate levels (p < 0.05) after training at the maximum workload achieved in the pre-training test. CONCLUSIONS: Training in the roomair-group resulted in a significant increase in the maximum power and total amount of work. In this group training could induce a physiologic response (increase of aerobic capacity), which was shown by significantly lower lactate levels at a comparable workload.

Exercise↗
PubMed1999

[The role of non-invasive positive pressure ventilation in lung volume reduction surgery of pulmonary emphysema--a survey of German hospitals].

BACKGROUND: Since the first publication by Cooper et. al. in 1994 of lung volume reduction surgery (LVRS) of emphysema a marked respiratory failure with hyperkapnia (PaCO2 > 55 Torr) has been regarded as an exclusion criterion for LVRS. PATIENTS AND METHOD: In a survey in German hospitals the question was asked whether non-invasive nasal ventilation (NIPPV) has a role in the management of LVRS. Of 12 hospitals 6 had experience with NIPPV and LVRS in a total of 19 patients with a mean FEV1 of 0.64 +/- 0.101. RESULTS: LVRS improved FEV1 by 0.20 +/- 0.181. Preoperative NIPPV was short (< 6 months) in 8 patients and resulted in improvement of physical condition and getting the patient used to NIPPV for better perioperative management. In 5 cases NIPPV was used on a long-term basis in order to allow the patient to be included in the LVRS program. In fact 7 of these 13 patients needed ventilation perioperatively, and 4 had to continue long-term NIPPV after surgery. In further 3 patients NIPPV was applied only perioperatively. One patient had to resume NIPPV after 15 months. Two patients started NIPPV 1 resp. 12 months after surgery. Two patients had bronchial cancer which was resected. Four patients died: 1 perioperatively after intubation, 2 after 3 resp. 13 months due to respiratory failure, 1 for cancer relapse after 20 months. CONCLUSION: NIPPV may be helpful in the planning and management of LVRS in patients with ventilatory failure with hypercarbia.

Female↗
PubMed1998

[Clinical significance of sleep apnea disorders after implantation of a cardioverter-defibrillator in patients with cardiac disease and sustained ventricular tachyarrhythmia].

The purpose of our study was to determine the prevalence of sleep related breathing disorders (SRBD) in patients with an implantable cardioverter-defibrillator (ICD) and to evaluate prospectively the possible influence of SRBD on arrhythmia recurrence and circadian arrhythmia variation as well as on cardiac mortality during long-term follow-up. Forty consecutive ICD recipients with cardiac disease and a documented history of spontaneous, life-threatening, ventricular tachyarrhythmias underwent full-night polysomnography and were followed for 2 years. In 16 of 40 patients (40%), SRBD were diagnosed (Apnea/Hypopnea Index (AHI) > 10); in 9 of these 16 patients (56%) central sleep apneas (CSA) occurred (in 8 of these 9 patients in combination with Cheyne-Stokes respiration). Seven of the 16 patients with SRBD (44%) revealed obstructive sleep apneas (OSA). AHI was 32 +/- 15 (12-60) in patients with CSA and 32 +/- 27 (11-86) in patients with OSA. Patients with and without SRBD were comparable concerning left ventricular ejection fraction, NYHA classification, cardiac disease, ICD indication, and concomitant medication. ICD registered ventricular tachyarrhythmias occurred in 10 of 24 patients (42%) without SRBD, in 4 of 9 patients (44%) with CSA, and in 3 of 7 patients (44%) with OSA. The numbers and circadian variation of episodes registered during follow-up in patients without SRBD, with OSA or CSA were comparable (14 +/- 25, median 4 vs 15 +/- 15, median 7 vs 4 +/- 5, median 2.5). The 2-year cardiac mortality was highest in patients with CSA (4/9 (44%) vs. 0/7 patients (0%) with OSA vs 3/24 patients (12.5%) without SRBD. Thus, the prevalence of SRBD in patients with chronic heart failure and a history of malignant ventricular tachyarrhythmias is high (40%) and the occurrence of CSA seems to be predictive for cardiac mortality in these patients. An influence of moderate SRBD on arrhythmia recurrence and circadian variation of spontaneous sustained tachyarrhythmic events could not be demonstrated.

Aged↗
PubMed1997

A new method for data presentation in incremental cardiorespiratory exercise testing.

In incremental cardiopulmonary exercise testing, the averaging of data is usually performed to provide group mean data for statistical purposes. They are usually presented as averaged maximum values, or as averaged data at different exercise levels. However, during incremental exercise testing the change in metabolic status may vary between subjects, thus averaging data may not classify the metabolic status accurately. We present an averaging method using a segmented ordinal scale based on individual maximal work performance and the anaerobic threshold (AT). Individual exercise data are grouped into ten classes ranging from unloaded exercise to maximal exercise. The classes are defined in relation to the AT, resulting in an ordinal scale of four classes for exercise data below the AT, one class at the AT and five classes beyond the AT. Resting and unloaded pedalling are treated as separate classes. For evaluation, this method of classification is compared to one based on an absolute scale of oxygen uptake (Cabs) and to another based on a relative scale in 10% steps of maximal oxygen uptake (Crel). Ten healthy male subjects (mean age 23.3 years) performed a ramp cycle ergometer test. When using the Cabs classification method for mean data averaging, mean values for performance at high-intensity exercise were calculated using data from only two of the ten subjects because of variations in individual work capacity. In addition, the AT data were distributed across four classes, thus anaerobic and aerobic exercise data were mixed. Using the Crel classification method enabled data for all ten subjects to be included in the calculation of every data point, but the AT values were still distributed across three classes, resulting in the mixing of anaerobic and aerobic exercise data. However, using the segmented ordinal scale method of classification enabled data from all ten subjects to be included in the calculation of all data points, and it permitted the grouping of the AT values into one class. Thus, this latter method more accurately represents the data of the whole group under study and it allows the metabolic status of the subjects to be taken into consideration.

Adult↗
PubMed1996

[The prevalence of sleep-related breathing disorders in patients with implanted cardioverter-defibrillators. The effect on the incidence and circadian distribution of malignant ventricular tachyarrhythmias].

OBJECTIVE: To determine the prevalence of sleep-related breathing disorders (SRBD) on patients who, because of malignant ventricular tachyarrhythmias associated with cardiac disease, have an implanted cardioverter-defibrillator (ICD). It was also investigated whether the frequency and circadian distribution of spontaneous ventricular tachycardia and (or) fibrillation (VTF) can be influenced by SRBD. PATIENTS AND METHODS: 29 consecutive ICD patients (28 men, one woman; mean age 64 +/- 8 years) were investigated by multifunction recordings. 22 patients had coronary heart disease, and seven dilated cardiomyopathy. For each patient the number of VIF episodes per month were recorded, as well as the percentage distribution of the episodes during the day per hour and after grouping into four time periods. RESULTS: SRBDs were recorded in 13 of the 29 patients (45%) (apnoea-hypopnea index [AHI] > 10). The other 16 patients had normal findings (AHI < or = 10). Mean frequency of the registered VTF attacks was similar in both groups (0.41/month with AHI < or = 10 vs 0.44/month with AHI > 10; difference not statistically significant). Averaged percentage distribution pattern showed a maximum frequency in both groups between 6 o'clock and 12 o'clock a.m. There was no significant increase of VTF during the night (10 o'clock p.m.-6 o'clock a.m.) in the group with SRBD (19% with AHI > 10 vs 18.2% with ATF < or = 10; difference not significant). CONCLUSION: There was a high prevalence of SRBD in the patients with ICD and underlying cardiac disease. No influence of SRBD on frequency and circadian distribution of VTF was demonstrated in patients with ICD during long-term observation.

Aged↗
PubMed1996

[Proportional assisted ventilation--clinical use of a new ventilation mode].

BACKGROUND: Proportional assist ventilation (PAV), a new mode for assist ventilation, allows the patient not only to trigger the ventilator but enables him to keep his breathing pattern. The basis of PAV is a positive feed back between patient and ventilator. PATIENTS AND METHOD: PAV was applied in 6 patients, who were under long-term ventilation and who were stable. The ventilator was adjusted to compensate for the endotracheal tube, different parts between 90 and 40% of resistance and elastance were assisted. Airway pressure, flow and tidal volume were measured. PAV was compared with pressure support ventilation (PSV). RESULT: No difference in blood gases were found in PAV as compared to PSV. Airway pressure were lower in PAV than in PSV (10.4 +/- 3.3 cm H2O vs. 18.8 +/- 5.9 cm H2O in PSV). Breathing frequency was higher (22.4 +/- 8.1 vs. 15.8 +/- 5.9 in PSV). CONCLUSION: The higher breathing frequencies in PAV were associated with the underlying diseases and resulted in a better synchronisation with the respiratory center output.

Humans↗
PubMed1996

Metabolic, endocrine, haemodynamic and pulmonary responses to different types of exercise in individuals with normal or reduced liver function.

UNLABELLED: The liver is central to the metabolic response to exercise but measurements of effects of reduced liver function on the physiological adaptation to exercise are scarce. We investigated metabolic, endocrine, pulmonary and haemodynamic responses to exercise in 15 healthy untrained controls (Co) and in 30 subjects with reduced liver function (i.e. liver cirrhosis, Ci). The following protocols were used: protocol 1 maximal oxygen uptake (VO2max) and anaerobic threshold (AT), protocol 2 stepwise increases in exercise intensity from 0 to 40% VO2max giving steady-stage conditions, protocol 3 1 h exercise at 20% VO2max. Muscle glycogen content was determined in 15 Ci. Spirometry was essentially normal in Ci. RESULT: protocol 1 Ci had impaired VO2max and reduced AT (P < 0.05). Basal plasma concentrations of insulin, glucagon, growth hormone and adrenaline were increased in Ci (P < 0.05); cortisol was normal. During exercise, only glucagon remained different between groups. In protocol 2 Ci had decreased resting respiratory exchange ratio (RQ: p < 0.05) associated with increased plasma concentrations of free fatty acids and glycerol. They had disproportionately enhanced lipolysis and RQ. heart rate (+24%), ventilation (+28%), thermal effects of exercise (+31%) and intrapulmonary shunt volume (+76%), which accounted for 11.7 (SD 3.0) or 7.4 (SD 0.9%) of cardiac output during exercise in Ci and Co, respectively (P < 0.05 for all the differences reported). The metabolic effects of Ci were independent of the clinical and nutritional state of the patients. In protocol 3 muscle glycogen content was highly variable in Ci, but mean values were normal [16.9 (SD 8.9) mumol.g-1 wet mass]. Glycogen content positively correlated with resting and exercise-induced RQ, but negatively correlated with the exercise-induced alterations in plasma glucose concentration. From these results we concluded that with reduced liver function VO2max and AT are reduced, but metabolic, pulmonary and haemodynamic responses per unit power output are enhanced. Muscle glycogen content would seem to contribute to the metabolic response, but its mobilization to be limited in individuals with reduced liver function.

Adult↗
PubMed1995

[Long-term follow-up of CPAP therapy in patients with obstructive sleep apnea].

The aim of the study was to investigate compliance of CPAP therapy in obstructive sleep apnea. CPAP therapy was adjusted in one night in the hospital. 104 patients (age 54.5 +/- 9.3 years) were asked by a standardized questionnaire for acceptance and side effects. 80% of the patients use CPAP regularly for 5.6 +/- 1.8 hours during the night. 51% use CPAP during the whole night. Patients and relatives report an improvement in clinical symptoms. The rate of side effects was high, only 11% were without any side effects. Major problems were skin problems under the CPAP mask (53%), 44% of patients reported dryness of the mouth, and 40% had problems with the noise of the unit. The rate of side effects as well as the short adjustment period for CPAP therapy did not seem to influence compliance.

Adult↗
PubMed1990

[Methodologic comparison of the polyfrequency oscillation method, transcutaneous oxygen pressure measurement and body plethysmography in bronchial provocation with methacholine].

A bronchial provocation challenge test was conducted with 30 subjects using metacholin. In randomised sequence lung function analysis tests were carried out with the bodyplethysmograph (Raw, FEV1) and the polyfrequent oscillation method (resistance, reactance between 2 and 52 Hz), whereas the transcutaneous oxygen pressure (tc-PO2) was measured continuously. Correlations between the various parameters, the change of the values at PD60 sGaw in relation to the initial values, the interindividual variability and the reactivity were determined. Medium correlations were found for the oscillatory parameters and Raw, whereas for tc-PO2 and Raw the correlation was markedly lower. In terms of percentage the greatest change was found in reactance, in relation to the initial value, followed by Raw and FEV1. The interindividual variability resulted in the highest values for the reactance, followed by Raw and FEV1. Interindividual variability showed the highest values for the reactance before oscillatory resistance and Raw. In respect of reactivity, reactance also had the highest values. Overall evaluation showed that bodyplethysmography and the polyfrequent oscillation method (reactance or resonance frequency) are comparably sensitive.

Airway Resistance↗
PubMed1990

[Diagnosis of lung function in patients with ankylosing spondylitis].

In a group of 55 men of 18 to 58 years of age who were suffering from ankylosing spondylitis, changes in lung function were analysed by measuring the static parameters and by differentiating between the thoracic and abdominal parts in breathing at rest and under stress, using CO2 rebreathing. In accordance with the reduction in vital capacity, the thoracic share is restricted already at rest. At rest, there is compensation via the abdominal compartment, in contrast to the stress in CO2 rebreathing in which the abdominal part does not compensate.

Adolescent↗
PubMed1990

[Measuring airway resistance with the oscillation method: Oscillaire and Custovit].

Measurement of airway resistance by the oscillation method was done on the one hand by means of the pseudo random noise method (Oszillaire, Jones Company) multifrequence from 6 to 26 Hz in steps of 2 Hz. In addition, the oscillatory resistance was also determined by means of the custo vit (Customed), the frequency of the pump producing the oscillation being variable so that measurements were carried out successively at different frequencies. 2 different versions were tested. In the first version the resonance frequency was measured and then monofrequently the pertaining resistance. In another version the impedance (total airway resistance) was measured at different frequencies in a frequency range between 6 and 20 Hz in steps of 2 Hz with both methods. Additionally, the airway resistance was also measured by bodyplethysmography. A clinical study was carried out in a group of 21 healthy subjects and 34 obstructed patients with asthma bronchiale and chronic obstructive lung disease. When measuring the airway resistance with the custo vit at the frequency of resonance there was poorer differentiation between normal and obstructed subjects compared to a measurement at a fixed frequencies yielded comparable values for both methods.

Airway Resistance↗
PubMed1989

Resistance measurement in normal and obstructed excised human lungs by means of the interrupter method.

In 6 normal and 7 obstructed excised human lungs the interrupter resistance (APTA, Jaeger Company) with an airway occlusion period of 100 ms was determined, by measuring the equivalent of the alveolar pressure at the end of the occlusion period. To check the pressure equilibration between the tracheal pressure and the alveolar space, catheters were put in the most peripheral layer of the lung. The lungs were ventilated in an artificial thorax. The airway resistance determined from the transbronchial pressure difference by the catheters was taken as a reference. Compared with the reference method, an overestimation of the airways resistance by the interrupter technique in normal lungs was found which was caused by an overshoot of the pressure equilibration during the occlusion period. In contrast, in severely obstructed lungs the pressure equilibration was not complete which led to an underestimation of the airways resistance by the interrupter technique. The best approximation of the airways resistance by the interrupter method was found in lungs with a low degree of obstruction.

Airway Obstruction↗