Intermittent hypoxic conditioning: experience and potential in cardiac rehabilitation programs

The review describes the experience in intermittent hypoxic conditioning protocols in rehabilitation programs for patients with cardiovascular diseases. Based on randomized controlled trials, the efficacy and safety of intermittent hypoxic conditioning in patients with cardiovascular disease, including those with multicomorbidity in clinical practice, have been analyzed. From a physiological and clinical standpoints, the review justifies the need for further controlled clinical trials on hypoxic conditioning with a longer follow-up period both to expand the clinical indications for this method and to develop optimal combinations with exercise within cardiac rehabilitation programs. Discovery of the key mechanisms of adaptation to oxygen concentration changes and further research on hypoxia physiology will expand the application of this method in clinical and rehabilitation medicine in cardiac patients

HYPOXIA-HYPEROXIA ADAPTATION AND INCREASED EXERCISE CAPACITY IN PATIENTS WITH CORONARY HEART DISEASE

Aim. To assess effectiveness and safety of a new rehabilitation method — interval hypoxia-hyperoxia training (IHHT) — in patients with chronic coronary heart disease (CCHD).Material and methods. This pilot study included 40 CCHD patients, Functional Class II–III (31 men and 9 women; mean age 61,7±7,7 years). The IHHT group (n=30) underwent 20 procedures (duration 40–50 minutes, 5 times a week), while the control group (n=10) underwent 20 similar placebo procedures. The REOXY device (AIMediqS.A., Luxemburg) was used for the creation of the gas mixtures with O2 content from 10% to 35–40%. At baseline and in the end of the treatment, individual hypoxia sensitivity was assessed in a 10-minute hypoxic test (HT). The IHHT procedure started with 5–7 minutes of mask inhalation of 12–11% О2, followed by 2–3 minutes of mask inhalation of 30% O2. The automatic switch between the gas mixtures followed the biological feedback principle; one procedure included 6–8 hypoxiahyperoxia cycles. Before and after the intervention phase, all participants underwent clinical and biochemical blood assay, rest ECG, submaximal treadmill test (time of the test, workload, and exercise capacity in metabolic equivalent units (MET)).Results. After the IHHT course, the main group demonstrated a significant increase in exercise capacity: test time increased by 34,1% (vs. —2,7% in controls), while exercise capacity (MET) increased by 15,8% (vs. 5,4% in controls), and the prevalence of angina attacks as the result of test termination significantly decreased. Improved exercise capacity was associated with a significant reduction in total cholesterol, plasma triglycerides, initially elevated blood pressure and resting heart rate, as well as with an elevated hypoxia tolerance threshold in the HT. In all participants, IHHT was well tolerated and free from adverse effects. Conclusion. The IHHT method increases exercise capacity in CCHDpatients, which is associated with lipid profile normalisation, blood pressure reduction, decreased number of angina attacks, and increased resistance to hypoxia

"SYMBIOTIC" HEMOFILTRATION FOR CHRONIC RENAL F AILURE COMPENSATION

AbstractWidely used nowadays hemodialysis and hemofiltration cannot replace completely the excretory function of human kidneys in the natural conditions of physiological regulation. The aim of our study is to develop and create a new method and apparatus for CRF patients «symbiotic» compensation, based on hemofiltration and healthy humans kidneys natural physiological functions, excluding mixing of partners blood.Method of «symbiotic» hemofiltration is based on mutual exchange of equivalent blood ultrafiltrate volumes between healthy person and CRF patient, needed to be cleansed from metabolites. During exchange procedure patient’s and a healthy person’s circulations are separated by hemofilters excluding blood mixing.During CRF patient’s blood cleansing from metabolic products separate hemofiltration of healthy donor and CRF patient in equal volumes is processed. Patient’s blood ultrafiltrate enters the bloodstream of a healthy person, as a healthy person ultrafiltrate in the same extent enters the bloodstream of CRF patient. At the same time remaining after filtration blood components of donor and patient are returned in their bloodstream respectively.Fundamentally important advantage of «symbiotic» hemofiltration is that CRF patient’s blood is cleansed from uremic metabolites due to healthy human kidneys natural physiological functions. «Symbiotic» hemofiltration is a highly effective physiological method of CRP patient’s blood purification from the uremic substances

Indicators of individual hypoxia resistance — a way to optimize hypoxic training for children

Objective. To develop a protocol for a normobaric hypoxic test and criteria of resistance assessment — normobaric hypoxia sensitivity in children.Characteristics of children and research methods. 56 healthy children aged from 8 to 12 years underwent a hypoxic test inhaling gas mixture with 10—11% of O2 through mask to create hypoxemia conditions (SpO2 = 80%). The authors used a normobaric hypoxic device (certified in the Russian Federation) to produce hypoxic and hyperoxic gas mixtures — ReOxy Cardio (S.A. Aimediq, Luxembourg) with an integrated pulse oximetry sensor (Masimo Rad-5, USA).During hypoxic test they monitored the arterial blood oxygen saturation (SpO2) and heart rate (HR, bpm), and there were automatically recorded the individual minimum values of SpO2 level (SpO2 min) and maximum heart rate (HR max). A “hypoxic phase” was terminated in case of decrease in SpO2 to 80% or lower, or breathing with a hypoxic gas mixture during 9 minutes. An additional criterion for termination was an increase in HR by 30% and higher over the initial level. After reaching one of the described criteria, the teenagers began to breathe ambient air and the authors determined the recovery time of SpO2 to 97%. In addition, the authors calculated the hypoxic index as desaturation/reoxygenation time ratio.Results. The authors developed a protocol for conductance and assessment of hypoxic resistance in children and adolescents. There were determined three types (phenotypes) of response to dosed normobaric hypoxia in adolescents: low, medium and high levels of dosed hypoxic stimulus resistance.Conclusion. The proposed hypoxic test protocol reflects the individual hypoxia tolerance and can be used to individualize hypoxic therapy courses, as well as additional diagnostic tool in assessing the adaptive capabilities and non-specific reactivity in children

APPLICATION OF INTERVALIC HYPOXIC-HYPEROXIC ENTRAINMENT TO PREVENTION OF INTRA AND EARLY POSTOPERATIONAL COMPLICATIONS IN CORONARY BYPASS GRAFTING

Aim. To assess possibility and safety of intervalic hypoxic-hyperoxic training (HHT) as a method of cardioprotection and metabolic adaptation of myocardium for onpump coronary bypass surgery.Material and methods. Totally, 80 coronary heart disease patients included, hospitalized to the clinics of aortic and cardiosurgery of the University hospital of Sechenov University. All had indications for the operation — direct myocardial revascularization with bypass grafting. In 5 days before surgery, according to the scheme of preparation, the patients were randomized to two groups (main — with HHT, and controls; n=40). The rate of complications was evaluated, during the operation and in post-surgery period. The level of troponin I was measured before operation, in 2 and 24 hours after, as well as level of lactate in venous blood before and after operation.Results. The rate of intraand early postsurgery complications in both groups did not differ significantly, though in the main there was tendency to decline of total rate of complications. In patients of HHT group median troponin I was significantly lower: 1,068 (0,388; 1,397) ng/L, when in controls — 1,980 (1,068; 3,239) ng/mL, р=0,012.Lactate level after HHT operation was significantly lower — 1,74 (1,23; 2,04) mM/L, comparing to the controls — 2,10 (1,80; 2,29) mM/L, р=0,04.Conclusion. The applicability and safety were demonstrated, of HHT as a method of cardioprotection in shunting of coronary arteries on-pump. Taken low number of  participants, it is important to conduct broader investigation on this type of entrainment

Chelyabinsk airburst, damage assessment, meteorite recovery, and characterization

The asteroid impact near the Russian city of Chelyabinsk on 15 February 2013 was the largest airburst on Earth since the 1908 Tunguska event, causing a natural disaster in an area with a population exceeding one million. Because it occurred in an era with modern consumer electronics, field sensors, and laboratory techniques, unprecedented measurements were made of the impact event and the meteoroid that caused it. Here, we document the account of what happened, as understood now, using comprehensive data obtained from astronomy, planetary science, geophysics, meteorology, meteoritics, and cosmochemistry and from social science surveys. A good understanding of the Chelyabinsk incident provides an opportunity to calibrate the event, with implications for the study of near-Earth objects and developing hazard mitigation strategies for planetary protectionGeoscience & EngineeringCivil Engineering and Geoscience