P.R. Bader

Acute hemodynamic changes by breathing hypoxic and hyperoxic gas mixtures in pulmonary arterial and chronic thromboembolic pulmonary hypertension

BACKGROUNDnThere is insufficient evidence to counsel patients with pulmonary hypertension undergoing altitude or air travel. We thus aimed to study hemodynamic response of patients with pulmonary arterial or chronic thromboembolic pulmonary hypertension (PAH/CTEPH) during changes in inspiratory oxygen partial pressure.nnnMETHODS AND RESULTSnConsecutive patients undergoing right heart catheterization had hemodynamic assessments whilst breathing ambient air (normoxia, FiO2 0.21, at altitude 490u202fm), nitrogen-enriched air (hypoxia, FiO2 0.16, simulated altitude 2600u202fm) and oxygen (hyperoxia, FiO2 1.0), each for 10u202fmin. Data from patients with PAH/CTEPH with mean pulmonary artery pressure (mPAP) ≥25u202fmmHg, pulmonary artery wedge pressure ≤15u202fmmHg, were compared to data from controls, mPAP <20u202fmmHg. 28 PAH/CTEPH-patients, 15 women, median age (quartiles) 62y (49;73), mPAP 35u202fmmHg (31;44), PaO2 7.1u202fkPa (6.8;9.3) and 16 controls, 12 women, 60y (52;69), mPAP 18u202fmmHg (16;18), PaO2 9.5u202fkPa (8.5;10.6) were included. Hypoxia reduced the PaO2 in PAH/CTEPH-patients by median of 2.3u202fkPa, in controls by 3.3u202fkPa, difference (95%CI) in change 1.0 (0.02 to 1.9), pu202f<u202f0.05. Corresponding changes in pulmonary vascular resistance, mPAP and cardiac output were nonsignificant in both groups. Hyperoxia decreased mPAP in PAH/CTEPH-patients by 4u202fmmHg (2 to 6), in controls by 2u202fmmHg (0 to 3), difference in change 3u202fmmHg (0 to 5), pu202f<u202f0.05.nnnCONCLUSIONSnIn patients with PAH/CTEPH, very short-term exposure to moderate hypoxia similar to 2600u202fm altitude or during commercial air travel did not deteriorate hemodynamics. These results encourage studying the response of PAH/CTEPH during daytrips to the mountain or air travel.

Effects on Cognitive Functioning of Acute, Subacute and Repeated Exposures to High Altitude

Objective: Neurocognitive functions are affected by high altitude, however the altitude effects of acclimatization and repeated exposures are unclear. We investigated the effects of acute, subacute and repeated exposure to 5,050 m on cognition among altitude-naïve participants compared to control subjects tested at low altitude. Methods: Twenty-one altitude-naïve individuals (25.3 ± 3.8 years, 13 females) were exposed to 5,050 m for 1 week (Cycle 1) and re-exposed after a week of rest at sea-level (Cycle 2). Baseline (BL, 520 m), acute (Day 1, HA1) and acclimatization (Day 6, HA6, 5,050 m) measurements were taken in both cycles. Seventeen control subjects (24.9 ± 2.6 years, 12 females) were tested over a similar period in Calgary, Canada (1,103 m). The Reaction Time (RTI), Attention Switching Task (AST), Rapid Visual Processing (RVP) and One Touch Stockings of Cambridge (OTS) tasks were administered and outcomes were expressed in milliseconds/frequencies. Lake Louise Score (LLS) and blood oxygen saturation (SpO2) were recorded. Results: In both cycles, no significant changes were found with acute exposure on the AST total score, mean latency and SD. Significant changes were found upon acclimatization solely in the altitude group, with improved AST Mean Latency [HA1 (588 ± 92) vs. HA6 (526 ± 91), p < 0.001] and Latency SD [HA1 (189 ± 86) vs. HA6 (135 ± 65), p < 0.001] compared to acute exposure, in Cycle 1. No significant differences were present in the control group. When entering Acute SpO2 (HA1-BL), Acclimatization SpO2 (HA6-BL) and LLS score as covariates for both cycles, the effects of acclimatization on AST outcomes disappeared indicating that the changes were partially explained by SpO2 and LLS. The changes in AST Mean Latency [ΔBL (−61.2 ± 70.2) vs. ΔHA6 (−28.0 ± 58), p = 0.005] and the changes in Latency SD [ΔBL (−28.4 ± 41.2) vs. ΔHA6 (−0.2235 ± 34.8), p = 0.007] across the two cycles were smaller with acclimatization. However, the percent changes did not differ between cycles. These results indicate independent effects of altitude across repeated exposures. Conclusions: Selective and sustained attention are impaired at altitude and improves with acclimatization.The observed changes are associated, in part, with AMS score and SpO2. The gains in cognition with acclimatization during a first exposure are not carried over to repeated exposures.

Effect of Acute, Subacute, and Repeated Exposure to High Altitude (5050 m) on Psychomotor Vigilance

Aim: High altitude (HA) hypoxia may affect cognitive performance and sleep quality. Further, vigilance is reduced following sleep deprivation. We investigated the effect on vigilance, actigraphic sleep indices, and their relationships with acute mountain sickness (AMS) during very HA exposure, acclimatization, and re-exposure. Methods: A total of 21 healthy altitude-naive individuals (25 ± 4 years; 13 females) completed 2 cycles of altitude exposure separated by 7 days at low altitude (LA, 520 m). Participants slept at 2900 m and spent the day at HA, (5050 m). We report acute altitude exposure on Day 1 (LA vs. HA1) and after 6 days of acclimatization (HA1 vs. HA6). Vigilance was quantified by reaction speed in the 10-min psychomotor vigilance test reaction speed (PVT-RS). AMS was evaluated using the Environmental Symptoms Questionnaire Cerebral Score (AMS-C score). Nocturnal rest/activity was recorded to estimate sleep duration using actigraphy. Results: In Cycle 1, PVT-RS was slower at HA1 compared to LA (4.1 ± 0.8 vs. 4.5 ± 0.6 s-1, respectively, p = 0.029), but not at HA6 (4.6 ± 0.7; p > 0.05). In Cycle 2, PVT-RS at HA1 (4.6 ± 0.7) and HA6 (4.8 ± 0.6) were not different from LA (4.8 ± 0.6, p > 0.05) and significantly greater than corresponding values in Cycle 1. In both cycles, AMS scores were higher at HA1 than at LA and HA6 (p < 0.05). Estimated sleep durations (TST) at LA, 1st and 5th nights were 431.3 ± 28.7, 418.1 ± 48.6, and 379.7 ± 51.4 min, respectively, in Cycle 1 and they were significantly reduced during acclimatization exposures (LA vs. 1st night, p > 0.05; LA vs. 5th night, p = 0.012; and 1st vs. 5th night, p = 0.054). LA, 1st and 5th nights TST in Cycle 2 were 477.5 ± 96.9, 430.9 ± 34, and 341.4 ± 32.2, respectively, and we observed similar deteriorations in TST as in Cycle 1 (LA vs. 1st night, p > 0.05; LA vs. 5th night, p = 0.001; and 1st vs. 5th night, p < 0.0001). At HA1, subjects who reported higher AMS-C scores exhibited slower PVT-RS (r = -0.56; p < 0.01). Subjects with higher AMS-C scores took longer time to react to the stimuli during acute exposure (r = 0.62, p < 0.01) during HA1 of Cycle 1. Conclusion: Acute exposure to HA reduces the PVT-RS. Altitude acclimatization over 6 days recovers the reaction speed and prevents impairments during subsequent altitude re-exposure after 1 week spent near sea level. However, acclimatization does not lead to improvement in total sleep time during acute and subacute exposures.

Réhabilitation de l’asthme à haute et basse altitude : étude randomisée contrôlée de groupes parallèles

Introduction Les conditions environnementales a haute altitude presentent peu de facteurs allergenes ou de pollution. Nous avons donc examine les effets amplificateurs de l’altitude (Tuja Ashu–Kirghizistan, 3200xa0m, haute altitude [HA]) compares a la meme rehabilitation faite a basse altitude (Bishkek–Kirghizistan, 760xa0m, basse altitude [BA]) sur le controle de l’asthme. Methode Des adultes asthmatiques vivant dans la zone de Bishkek, diagnostiques conformement aux recommandations de la Global Initiative for Asthma, ont ete recrutes pour cette etude randomisee controlee. Ils ont ete affectes au hasard pour 3xa0semaines dans un hopital situe en haute ou basse altitude. La, ils ont beneficie d’un traitement comprenant de l’education therapeutique, de l’entrainement a l’endurance et a la force, des exercices respiratoires et des promenades guidees (30xa0a 45xa0min, 5xa0×/semaine). Les parametres evalues etaient les suivantsxa0: la variabilite des modifications du debit expiratoire de pointe (DEP) [(Plus haut du jour–plus bas du jour)/moyenne des plus hauts et plus bas] et les notes du questionnaire de controle de l’asthme (Asthma Control Questionnaire [ACQ]) du debut a la fin de la rehabilitation et 3xa0mois apres, entre les groupes. Resultats Cinquante asthmatiques (46xa0atopiques, 34xa0femmes) ont ete randomises [moyenne (quartiles) BAxa0: âge 47 (34xa0; 53) ans, FEV1xa0% predite 74 (53xa0; 99)xa0%, DEP 311 (274xa0; 378) L/minxa0; HAxa0: âge 43 (33xa0; 49) ans, FEV1xa0% predite 80 (74xa0; 86)xa0%, DEP 326 (261xa0; 368)L/min]. Les parametres varient de la maniere suivantexa0: variabilite du DEP (mediane IC 95xa0%)xa0: −10,4xa0% (−21,3xa0a −3,4, pxa0 xa00,05) en BA, difference −5xa0% (−13,6xa0a 5,0). Le score de l’Asthma Control Questionnaire diminue en HA plus qu’en BAxa0: −1,1 (−1,3xa0a −0,7, pxa0 xa00,05) vs −0,9 (−1,3xa0a −0,3, pxa0 Conclusions La rehabilitation de l’asthme est hautement efficace pour ameliorer le controle de l’asthme en termes de variabilite et de symptomes de DEP, a un degre similaire tant a haute qu’en basse altitude. Signification L’etude a un impact important sur les patients concernes et les pays a faible revenu tels que le Kirghizistan, ou les medicaments sont moins disponibles et ou nous avons pu montrer que la rehabilitation de l’asthme est efficace dans le traitement des symptomes et la variabilite du debit expiratoire de pointe.

Right heart function and pulmonary pressure in asthma patients during 17 days at high-altitude

Objectives: Asthmatics may benefit from the climate at altitude. But the hypoxic environment may also be associated with adverse effects, e.g. right heart strain due to increased pulmonary artery pressure (PAP). We studied the right ventricular function (RVF) and SpO2 at lowland, after arrival at 3200m and after 17 days at that altitude in asthmatics. Methods: 22 asthmatics (living Results: The mPAP (mean±SD) was 13.5±5.4mmHg at 760m, 18.5±5.5mmHg after one and 18.2±5.5mmHg after 17 nights at 3200m (p Conclusions: In otherwise healthy asthmatics exposure to high altitude induces a significant increase in mPAP and heart rate with a decrease in SI resulting in an unchanged CI. During the 17 days at 3200m there is no further change in the indices of RVF despite increasing SpO2. Thus, respiratory acclimatization is more rapid than the one of the pulmonary circulation.

Asthma rehabilitation at high vs. low altitude: randomized controlled parallel-group trial

Allergens and pollution are reduced at altitude. We investigated the additive effect of asthma rehabilitation at high altitude (Tuja Ashu, 3200m, HA) compared to the same rehabilitation at low altitude (Bishkek, 760m, LA) on asthma control. For this randomized controlled trial adult asthmatics diagnosed according to GINA living in the Bishkek area ( .05), difference ‑5(‑13.6 to 5.0)%. ACQ was reduced at HA vs. LA by -1.1(-1.3 to -0.7, p .05) vs. -0.9(-1.3 to -0.3, p Asthma rehabilitation is highly effective in improving asthma control in terms of PEF-variability and symptoms, both at LA and HA to a similar degree.