Christian Schirlo

Influence of Altitude Exposure on Coronary Flow Reserve

Background—Although no data exist on the effect of altitude exposure on coronary flow reserve (CFR), patients with coronary artery disease (CAD) are advised not to exceed moderate altitudes of ≈2500 m above sea level. We studied the influence of altitude on myocardial blood flow (MBF) in controls and CAD patients. Methods and Results—In 10 healthy controls and 8 patients with CAD, MBF was measured by positron emission tomography and 15O-labeled water at rest, during adenosine stress, and after supine bicycle exercise. This protocol was repeated during inhalation of a hypoxic gas mixture corresponding to an altitude of 4500 m (controls) and 2500 m (CAD). Workload was targeted to comparable heart rate–blood pressure products at normoxia and hypoxia. Resting MBF increased significantly in controls at 4500 m (+24%, P <0.01) and in CAD patients at 2500 m (+24%, P <0.05). Altitude had no influence on adenosine-induced hyperemia and CFR. Exercise-induced hyperemia increased significantly in controls (+38%, P <0.01) at 4500 m (despite a reduction in workload, −28%, P <0.0001) but not in CAD patients at 2500 m (moderate decrease in workload, −11%, P <0.05). Exercise-induced reserve was preserved in controls (+10%, P =NS) but decreased in CAD patients (−18%, P <0.005). Conclusions—At 2500 m altitude, there is a significant decrease in exercise-induced reserve in CAD patients, indicating that compensatory mechanisms might be exhausted even at moderate altitudes, whereas healthy controls have preserved reserve up to 4500 m. Thus, patients with CAD and impaired CFR should be cautious when performing physical exercise even at moderate altitude.

Changes of Cerebral Blood Flow during Short-Term Exposure to Normobaric Hypoxia

Decreased arterial partial oxygen pressure (PaO2) below a certain level presents a strong stimulus for increasing cerebral blood flow. Although several field studies examined the time course of global cerebral blood flow (gCBF) changes during hypoxia at high altitude, little was known about the regional differences in the flow pattern. Positron emission tomography (PET) with [15O]H2O was used on eight healthy volunteers to assess regional cerebral blood flow (rCBF) during short-term exposure to hypoxia corresponding to simulated altitudes of 3,000 and 4,500 m. Scans at the simulated altitudes were preceded and followed by baseline scans at the altitude of Zurich (450 m, baseline-1 and baseline-2). Each altitude stage lasted 20 minutes. From baseline to 4,500 m, gCBF increased from 34.4 ± 5.9 to 41.6 ± 9.0 mL · minute−1 · 100 g−1 (mean ± SD), whereas no significant change was noted at 3,000 m. During baseline-2 the flow values returned to those of baseline-1. Statistical parametric mapping identified the hypothalamus as the only region with excessively increased blood flow at 4,500 m (+32.8% ± 21.9% relative to baseline-1). The corresponding value for the thalamus, the structure with the second largest increase, was 19.2% ± 16.3%. Compared with the rest of the brain, an excessive increase of blood flow during acute exposure to hypoxia is found in the hypothalamus. The functional implications are at present unclear. Further studies of this finding should elucidate its meaning and especially focus on a potential association with the symptoms of acute mountain sickness.

Bologna in Medicine Anno 2012: Experiences of European medical schools that implemented a Bologna two-cycle curriculum – An AMEE-MEDINE2 survey

Background: The 1999 Bologna Agreement implies a European harmonization of higher education using three cycles: bachelor and master before doctorate. Undergraduate medical programmes were restructured in only seven of the 47 countries. Aim: Given the debate about a two-cycle system in undergraduate medical education, providing an overview of experiences in medical schools that applied this structure was the purpose of this investigation. Methods: In 2009, an AMEE-MEDINE2 survey was carried out among all the 32 medical schools that applied the two-cycle system in medicine. At the end of 2011, a member-check validation using a draft manuscript was carried out to complete an accurate up-to-date impression. Results: All the 32 schools responded initially; 26 schools responded to the second round. All schools had implemented the two-cycle system (all but one in a 3 + 3 year model) with hardly any problems. All reported smaller or larger curriculum improvements, often triggered, but not caused, by the two-cycle system. No school reported that introducing the system interfered with any desired curriculum development, particularly horizontal or vertical integration. Conclusion: In 32 of the 442 medical schools in Bologna signatory countries, introducing a two-cycle model for basic medical education was successfully completed. However, harmonization of medical training in Europe requires further international collaboration.

Characteristics of the ventilatory response in subjects susceptible to high altitude pulmonary edema during acute and prolonged hypoxia.

The present study compares the changes in ventilation in response to sustained hypobaric hypoxia and acute normobaric hypoxia between subjects susceptible to high altitude pulmonary edema (HAPE-S) and control subjects (C-S). Seven HAPE-S and five C-S were exposed to simulated high altitude of 4000 m for 23 h in a hypobaric chamber. Resting minute ventilation (V(E)), tidal volume (V(T)), and respiratory frequency (f(R)), as well as the end-tidal partial pressures of oxygen (P(ET(O2))) and carbon dioxide (P(ET(CO2))) were measured in all subjects sitting in a standardized position. Six measurement periods were recorded: ZH1 at 450 m at Zurich level, HA1 on attaining 3600 m altitude, HA2 after 20 min at 4000 m, HA3 after 21 h and HA4 after 23 h at 4000 m altitude, and ZH2 immediately after recompression to Zurich level. At ZH1 and HA3, the measurements were first done in lying, then in sitting, and afterwards in standing. Peripheral arterial oxygen saturation (Sa(O2)) was continuously recorded. All respiratory parameters were also measured during exercise lasting 30 min, the work load being 50% of maximal oxygen consumption (V(O2max)) at Zurich level and 26% of the Zurich V(O2max) at 4000 m. V(E), P(ET(O2)) and P(ET(CO2)) did not significantly differ between HAPE-S and C-S at rest and during exercise periods at Zurich level and at high altitude. However, Sa(O2) was significantly lower in HAPE-S than in C-S at rest and during exercise at 4000 m. Breathing through the mouthpiece during ventilation measurements increased significantly the Sa(O2) in HAPE-S in posture tests at HA3. This effect was most pronounced in the supine posture, in which HAPE-S had the lowest Sa(O2) values. These data provide evidence that (1) gas exchange might be impaired on the level of ventilation-perfusion mismatch or due to diffusion limitation in HAPE-S during the first 23 h of exposure to a simulated altitude of 4000 m, and (2) contrary to C-S, the Sa(O2) in HAPE-S is significantly affected by body position and by mouthpiece breathing.

Interprofessionelle Kommunikationsprozesse – schwierige Gesprächssituationen mit Patientinnen und Patienten

Zur ärztlichen Aufgabe gehört unter anderem das Überbringen von schlechten Nachrichten an Patienten und ihre Angehörigen. schlechte Nachrichten werden definiert als „[Nachricht], welche in einem kognitiven, emotionalen oder sich auf das Verhalten auswirkenden Defizit in der Person, welche die Nachricht erhält, resultiert“. Dieses Defizit hält für einige Zeit an, nachdem die Nachricht überbracht wurde ([13], s. 496). Die Bewertung, ob eine Mitteilung in die kategorie „schlechte Nachrichten“ gehört, ist für den Patienten subjektiv. Der Arzt kann versuchen, sich in den Patienten hineinzuversetzen, aber die abschließende Beurteilung der Nachricht liegt beim Patienten. es gibt diverse studien über die Ansichten von Ärzten über das Überbringen schlechter Nachrichten [2, 4, 9]. Viele Ärzte haben das Überbringen schlechter Nachrichten im Rahmen ihres studiums oder ihrer Weiterbildung nicht gelernt [7] und empfänden eine Ausbildung in diesem Gebiet als hilfreich [2]. Die Patienten wünschen sich meistens auch, dass die Ärzte sie ehrlich über ihre Diagnose aufklären [3, 8]. Medizinstudierende der universität Zürich erlernen in ihrem kernstudium die Grundlagen der kommunikation und Interaktion. Für die Pflegestudierenden an der Höheethik Med (2012) 24:241–244 DOI 10.1007/s00481-011-0177-1