Biomedical subjects

P Dür

Publications and source records attributed to P Dür.

5 recordsLinked to original sources

PubMed1995

[Electrolyte changes during and after voluntary hyperventilation].

Paresthesia and tetanic finger cramps during hyperventilation-induced respiratory alkalosis are believed to derive from a pH-dependent decrease of ionized serum calcium. In the study reported here, ionized serum calcium, total calcium and total protein were measured during a three-minute hyperventilation period in ten volunteers. During hyperventilation finger paresthesias appeared in all probands without proof of any significant change in ionized serum calcium (1.26 +/- 0.05 mmol/l at the end of the three-minute hyperventilation period). Total protein increased as a consequence of hyperventilation-induced transient hemo-concentration. Paresthesias and tetanic finger cramps during the three-minute hyperventilation could not be related to changes of ionized serum calcium; however the other electrolytes, i.e. sodium, magnesium, potassium, chloride, phosphate and bicarbonate, showed, with the exception of sodium, significant changes.

Adult↗

PubMed1995

Physical work capacity with rate responsive ventricular pacing (VVIR) versus dual chamber pacing (DDD) in patients with normal and diminished left ventricular function.

To determine the benefit of atrial contribution on work capacity in relation to left ventricular ejection fraction, we studied 17 patients (68 +/- 13 years) with dual chamber pacemakers (DDD) implanted for high degree atrioventricular (AV) block. In random order they were assigned to rate responsive ventricular (VVIR) and to atrial triggered ventricular (VDD) stimulation. Maximum oxygen uptake (max VO2), that correlates best with work capacity, was measured by spiroergometry at a respiratory quotient of 1.1 during treadmill exercise test. Left ventricular ejection fraction at rest was determined by radionuclide ventriculography during VDD-stimulation and an AV delay of 150 ms. There were no differences between these two pacing modes relating heart rate, blood pressure, minute ventilation, exercise duration and maximal work load. In eight patients with an ejection fraction > 50% (60 +/- 10%), but not in nine patients with an ejection fraction < 50% (41 +/- 10%), maximum oxygen uptake was significantly higher (P < 0.01) during atrial triggered ventricular pacing (1440 +/- 533 ml/min) compared with rate responsive ventricular pacing (1328 +/- 536 ml/min). Thus, rate responsive single chamber pacemakers largely enable the same work capacity as dual chamber pacemakers in patients with high degree AV block. Patients with normal left ventricular function may profit most from preserved AV synchrony as shown by the higher maximum oxygen uptake on exercise.

Adult↗

PubMed1995

[Simultaneous measurement of arterial and end-expiratory carbon dioxide before, during and after voluntary hyperventilation].

Hyperventilation syndrome is considered an established diagnosis if it is confirmed that the patient's complaints correlate with arterial hypocapnia. In the diagnostic criteria set up by a group in Nijmegen, paCO2 is determined indirectly by measuring the end tidal CO2. Values below 4 kPa measured at rest and 10 or more minutes after deliberate hyperventilation are classified positive diagnostic criteria for hyperventilation syndrome. However, it has not been proven that end tidal pCO2 agrees well with paCO2 during the entire manoeuvre. We performed simultaneous measurements of both parameters in 10 healthy non-smokers, before, during and after 3 minutes of deliberate hyperventilation. A comparison of the values employed for diagnosing a hyperventilation syndrome (during normal respiration before and 10 and more minutes after hyperventilation) yields a mean difference of 0.39 kPa according to the statistical computation described by Bland and Altman (limits of the range of agreement between 0.98 and -0.18). The end tidal CO2 values measured during the normal respiratory phase as well as 10 and more minutes after hyperventilation, agree well with the arterial values (the arterial values being slightly higher). During and shortly after hyperventilation the values obtained by both methods differ from one another, so that the exact degree of hypocapnia during a hyperventilation period cannot be assessed by measuring the end tidal CO2.

Adult↗

PubMed1994

Importance of an individually programmed atrioventricular delay at rest and on work capacity in patients with dual chamber pacemakers.

Despite higher costs, expenditure, and the necessity of repeatedly reprogramming of dual chamber pacemakers, they are increasingly implanted to achieve an optimal work capacity. The influence of an individually programmed atrioventricular (AV) delay between 100-250 msec on physical work capacity in 12 patients (68 +/- 16 years) with dual chamber pacemakers implanted for high degree AV block was studied. During radionuclide ventriculography at rest the "optimal AV delay" with the maximal achieved left ventricular ejection fraction and the "most unfavorable AV delay" with the least achieved ejection fraction were determined. The ejection fraction at rest with the "optimal AV delay" was 51 +/- 14% and with the "most unfavorable AV delay" 45 +/- 15% (P < 0.001). In random order each patient was assigned to either AV delay and a spiroergometry was performed to determine maximum oxygen uptake (max VO2), which correlates best with work capacity, at a respiratory quotient of 1.1. The results show neither a difference in maximum oxygen uptake (1,262 +/- 446 mL/min with the optimal AV delay, 1,248 +/- 400 mL/min with the most unfavorable AV delay, respectively) nor in heart rate, blood pressure, exercise duration, maximal workload, and minute ventilation. Thus, an individually programmed AV delay affects left ventricular ejection fraction at rest. In contrast, an individually programmed AV delay has no influence on physical work capacity in patients with a dual chamber pacemaker.

Adult↗

PubMed1993

[Bronchiolitis obliterans organizing pneumonia (BOOP)--chronic organized pneumonia (COP). Diagnosis, therapy and course].

Cryptogenic organizing pneumonia (COP) or bronchiolitis obliterans organizing pneumonia (BOOP) designates a disease characterized by particular histopathological features. Symptoms and clinical findings are more or less typical and the etiology of the disease is unknown in most of the cases. We report on 7 patients in whom the diagnosis was established by open lung biopsy during a workup for persistent pulmonary infiltrates. The clinical findings, the radiological features and the course during treatment with corticosteroids are analyzed. In all patients the symptoms improved. In two cases we observed relapses after discontinuing the corticosteroids or diminishing the dose. These relapses again responded to steroids, but in one patient progressive pulmonary restriction was noticed despite continuous treatment.

Biopsy↗