Taylor, Bryan J.

Background Whether lung fluid accumulates in acclimating individuals at high altitude (HA) remains controversial. Purpose To assess the effect of HA on lung fluid regulation. Methods/Results Systolic pulmonary artery pressure (sPAP) (echo), lung diffusing capacity for CO (DLCO), pulmonary capillary blood volume (Vc), alveolar‐capillary conductance (Dm) (single breath method), ultrasound lung comets (ULCs) and pulmonary function (PFTs) were assessed in 8 healthy adults at sea‐level and after 1 and 9 days at Mt. Everest Base Camp (EBC), Nepal (5150 m). Also, after 5 days at EBC, DLCO and PFTs were assessed in 5 subjects pre‐and post‐acute albuterol administration. EBC was reached after an 8 d hike at progressively increasing altitudes starting at 2800 m. Altitude exposure increased sPAP, had no effect on DLCO, increased Dm and decreased Vc with a subsequent increase in Dm/Vc, and decreased the number of ULCs (Table 1). There was no change in FVC or FEV 1 but an increase in MEF 50 . Albuterol administration increased PEF (11.85±1.52 vs. 12.40±1.45 L/s) and MEF 50 (4.85±0.77 vs. 6.00±1.30 L/s) but had no effect on DLCO, Dm or Dm/Vc. Conclusion These data suggest that lung fluid is decreased in acclimating healthy humans at high altitude. Funding: Mayo Clinic & The North Face.

Background Heart failure (HF) is associated with impaired exercise pulmonary gas exchange (PGX) that is likely related to the development and severity of pulmonary hypertension (PH). Purpose To determine whether PGX measures differentiate HF patients with reactive PH from patients with passive PH or no PH. Methods/Results Pulmonary arterial pressure (P AP ), pulmonary wedge pressure (P WP ), transpulmonary pressure gradient (TPG) and PGX indices [end‐tidal CO 2 (P ET CO 2 ), ventilatory efficiency (V E /VCO 2 ), O 2 pulse, estimated pulmonary arterial capacitance (GX CAP )] were assessed simultaneously at rest and during cycle exercise in 38 HF patients undergoing right heart catheterization. Post hemodynamic evaluation, patients were classified as having no PH ( n = 12), passive PH ( n = 10) or reactive PH ( n = 16). TPG increased during exercise in all groups but was greater at end exercise in the reactive PH vs. the passive PH and no PH patients (21±9 vs. 14±7 vs. 12±7 mmHg). At an equivalent VO 2 , P ET CO 2 , O 2 pulse and GX CAP were higher and V E /VCO 2 ratio lower in the no PH and, to a lesser extent, in the passive PH vs. the reactive PH subjects (Figure 1). Conclusion Noninvasive measures of PGX during exercise appear to differentiate HF patients with reactive PH from patients with passive PH or no PH and may be a useful adjunct to invasive catheterization in assessing PH type and severity. HL71478, AHA12POST12070084, Gilead Science

Asthma, chronic obstructive pulmonary disease, and other respiratory disorders often occur concurrently with heart failure (HF). HF patients with respiratory disease can improve lung function and, therefore, quality of life with β‐agonists. Beta‐agonist use remains controversial as it has been linked with increased mortality risk; however, recent studies that account for co‐morbidities find no association between β‐agonist use and mortality. Previous studies exploring the cardiovascular effect of β‐agonist use in HF are primarily retrospective and focus on heart rate (HR). We have previously demonstrated altered cardiovascular function in response to albuterol in healthy subjects. In the present study we sought to comprehensively assess the cardiovascular effects of albuterol sulfate using cardiac output (Q), stroke volume (SV), HR, systolic, diastolic, and mean arterial blood pressure (SBP, DBP, MAP, respectively) and systemic vascular resistance (SVR). We hypothesized that cardiovascular parameters would be altered 30‐minutes following albuterol administration, and that HF patients using β‐blockers would have an attenuated response. Twenty‐two healthy and twenty‐two HF subjects were recruited (age=56±13 vs. 62±12yrs; height=175±10 vs. 176±9cm; weight=78±15 vs. 93±20; BMI=26±4 vs. 30±6; and BSA=2.08±0 vs. 1.93±0m 2 , for healthy and HF, respectively, p<0.05 for weight, BMI, and BSA). We found that HR and Q increased in healthy but not HF subjects at 30min following albuterol. Patients who were not on β‐blockers (n=4, 18%) had an increase in SV and a decrease in SVR with albuterol, while there was no change in patients who were on β‐blockers (n=14, 64%). These data suggest that HF patients have an attenuated cardiovascular response to inhaled albuterol, particularly with concurrent β‐blocker usage.

Background It is documented that cognitive performance can diminish with altitude, but the sensitivity of specific tests have not been investigated. Our objective was to assess and compare cognitive performance from several tests and relate this to quality of sleep and acute mountain sickness (AMS). Methods During an Everest expedition, 3 cognitive tests (Stroop, Trail Making, and a proprietary motor accuracy test) were used along with a questionnaire to assess sleep and AMS. Six athlete climbers and 9 core team members were assessed pre and post‐expedition and at several time points during the expedition (up to 17,500 ft). Results To normalize for individual differences, scores were assessed as % change from baseline. There was no difference in the variation between repeated attempts in a single testing session (0.19<p<0.87), demonstrating that each test was reproducible. There was no decrement in test scores with altitude, nor was there an association with reported sleep quality. The Stroop performance was associated with AMS (p<0.05) and trending with headache (p< 0.15). The in‐house motor test trended towards an association with AMS and headache (p<0.15). However, the trail making test was not associated with AMS/headache. Conclusion With appropriate acclimatization, cognitive performance is maintained at altitude but is linked to presence of headache and AMS. Mayo Clinic and TNF.

BACKGROUND High altitude (HA) exposure influences appetite, protein synthesis and breakdown, and aerobic capacity. Thus, HA exposure typically causes weight (wt) loss, while the impact on aerobic capacity upon return to sea level is more variable. OBJECTIVE To examine the influence of hypobaric hypoxia on body composition and exercise capacity in elite HA climbers (n=4, 2 female) acclimating at ≥5,150 m over 2 mo. relative to trekkers (n=8, 0 female) acclimating at 5,150 m over 2 wks (Mt. Everest, Nepal). Each elite climber successfully summited Mt. Everest. METHODS Body composition (DEXA, skin folds, wt) and exercise capacity (treadmill) were assessed before and within 2 wks post HA. RESULTS HA exposure increased Hct and Hb, with peak values of 52±5% and 18±2 g/dl, and 50±3% and 17±1 g/dl for the climbers and trekkers, respectively. HA decreased lean and fat tissue in both the climbers (lean −4.4±2.3%, fat −8.2±4.0%) and trekkers (lean −1.8±1.6%, fat −5.8±6.1%) (all P ≤0.06). No change was observed in skin folds for either group. Wt decreased in the climbers (−5±2%, P <0.03) and trekkers (−3±1%, P <0.01). There was no change in VO 2max pre‐to post‐HA in either group (climbers 3.26 ± 0.37 vs. 3.27 ± 0.61 L/min; trekkers 3.60 ± 0.54 vs. 3.66 ± 0.43 L/min). CONCLUSION HA results in both lean and fat tissue loss in well acclimatized climbers and trekkers with little subsequent impact on aerobic capacity. Mayo Clinic & TNF.