Human Physiology an Integrated Approach
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Everest and Oxygen—Ruminations by a Climber Anesthesiologist by David Larson, M.D
Everest and Oxygen—Ruminations by a Climber Anesthesiologist By David Larson, M.D. Gaining Altitude and Losing Partial Pressure with Dave and Samantha Larson Dr. Dave Larson is an obstetric anesthesiologist who practices at Long Beach Memorial Medical Center, and his daughter Samantha is a freshman at Stanford University. Together they have successfully ascended the Seven Summits, the tallest peaks on each of the seven continents, a feat of mountaineering postulated in the 1980s by Richard Bass, owner of the Snowbird Ski Resort in Utah. Bass accomplished it first in 1985. Samantha Larson, who scaled Everest in May 2007 (the youngest non-Sherpa to do so) and the Carstensz Pyramid in August 2007, is at age 18 the youngest ever to have achieved this feat. Because of varying definitions of continental borders based upon geography, geology, and geopolitics, there are nine potential summits, but the Seven Summits is based upon the American and Western European model. Reinhold Messner, an Italian mountaineer known for ascending without supplemental oxygen, postulated a list of Seven Summits that replaced a mountain on the Australian mainland (Mount Kosciuszko—2,228 m) with a higher peak in Oceania on New Guinea (the Carstensz Pyramid—4,884 m). The other variation in defining summits is whether you define Mount Blanc (4,808 m) as the highest European peak, or use Mount Elbrus (5,642 m) in the Caucasus. Other summits include Mount Kilimanjaro in Kenya, Africa (5,895 m), Vinson Massif in Antarctica (4,892 m), Mount Everest in Asia (8,848 m), Mount McKinley in Alaska, North America (6,194 m), and Mount Aconcagua in Argentina, South America (6,962 m). -
Physiologic Effects of Noninvasive Ventilation
Physiologic Effects of Noninvasive Ventilation Neil R MacIntyre Introduction NIV Can Augment Minute Ventilation NIV Unloads Ventilatory Muscles NIV Resets the Ventilatory Control System Alveolar Recruitment and Gas Exchange Other Physiologic Effects of NIV: Intended and Unintended Maintaining Upper-Airway Patency Reducing Imposed Triggering Loads From Auto-PEEP Cardiac Interactions: Both Beneficial and Harmful Ventilator-Induced Lung Injury Production of Auto-PEEP Patient-Ventilator Interactions Summary Noninvasive ventilation (NIV) has a number of physiologic effects similar to invasive ventilation. The major effects are to augment minute ventilation and reduce muscle loading. These effects, in turn, can have profound effects on the patient’s ventilator control system, both acutely and chron- ically. Because NIV can be supplied with PEEP, the maintenance of alveolar recruitment is also made possible and the triggering load imposed by auto-PEEP can be reduced. NIV (or simply mask CPAP) can maintain upper-airway patency during sleep in patients with obstructive sleep apnea. NIV can have multiple effects on cardiac function. By reducing venous return, it can help in patients with heart failure or fluid overload, but it can compromise cardiac output in others. NIV can also increase right ventricular afterload or function to reduce left ventricular afterload. Potential det- rimental physiologic effects of NIV are ventilator-induced lung injury, auto-PEEP development, and discomfort/muscle overload from poor patient–ventilator interactions. Key words: invasive ventilation; noninvasive ventilation; minute and alveolar ventilation; ventilation distribution; ventilation-perfusion match- ing; control of ventilation; ventilatory muscles; work of breathing; patient–ventilator interactions; ventilator- induced lung injury. [Respir Care 2019;64(6):617–628. -
DEATH ZONE FREERIDE About the Project
DEATH ZONE FREERIDE About the project We are 3 of Snow Leopards, who commit the hardest anoxic high altitude ascents and perform freeride from the tops of the highest mountains on Earth (8000+). We do professional one of a kind filming on the utmost altitude. THE TRICKIEST MOUNTAINS ON EARTH NO BOTTLED OXYGEN CHALLENGES TO HUMAN AND NATURE NO EXTERIOR SUPPORT 8000ERS FREERIDE FROM THE TOPS MOVIES ALONE WITH NATURE FREERIDE DESCENTS 5 3 SNOW LEOS Why the project is so unique? PROFESSIONAL FILMING IN THE HARDEST CONDITIONS ❖ Higher than 8000+ m ❖ Under challenging efforts ❖ Without bottled oxygen & exterior support ❖ Severe weather conditions OUTDOOR PROJECT-OF-THE-YEAR “CRYSTAL PEAK 2017” AWARD “Death zone freeride” project got the “Crystal Peak 2017” award in “Outdoor project-of-the-year” nomination. It is comparable with “Oscar” award for Russian outdoor sphere. Team ANTON VITALY CARLALBERTO PUGOVKIN LAZO CIMENTI Snow Leopard. Snow Leopard. Leader The first Italian Snow Leopard. MC in mountaineering. Manaslu of “Mountain territory” club. Specializes in a ski mountaineering. freeride 8163m. High altitude Ski-mountaineer. Participant cameraman. of more than 20 high altitude expeditions. Mountains of the project Manaslu Annapurna Nanga–Parbat Everest K2 8163m 8091m 8125m 8848m 8611m The highest mountains on Earth ❖ 8027 m Shishapangma ❖ 8167 m Dhaulagiri I ❖ 8035 m Gasherbrum II (K4) ❖ 8201 m Cho Oyu ❖ 8051 m Broad Peak (K3) ❖ 8485 m Makalu ❖ 8080 m Gasherbrum I (Hidden Peak, K5) ❖ 8516 m Lhotse ❖ 8091 m Annapurna ❖ 8586 m Kangchenjunga ❖ 8126 m Nanga–Parbat ❖ 8614 m Chogo Ri (K2) ❖ 8156 m Manaslu ❖ 8848 m Chomolungma (Everest) Mountains that we climbed on MANASLU September 2017 The first and unique freeride descent from the altitude 8000+ meters among Russian sportsmen. -
Deadly High Altitude Pulmonary Disorders: Acute Mountain Sickness
Research Article Int J Pul & Res Sci Volume 1 Issue 1 - April 2016 Copyright © All rights are reserved by Michael Obrowski DOI : 10.19080/IJOPRS.2016.01.555553 Deadly High Altitude Pulmonary Disorders: Acute Mountain Sickness (AMS); High Altitude Pulmonary Edema (HAPE) and High Altitude Cerebral Edema (HACE): A Clinical Review Michael Obrowski1* and Stephanie Obrowski2 1Doctor of Medicine (M.D. – 2000); Assistant Professor of Anatomy; CEO, Chief Physician and Surgeon of Wilderness Physicians, European Union 2Doctor of Medicine (M.D. – 2019); Medical University of Łódź; President of Wilderness Physicians, European Union Submission: January 26, 2016; Published: April 15, 2016 *Corresponding author: Michael Obrowski, M.D., Doctor of Medicine (M.D. – 2000); Assistant Professor of Anatomy; CEO, Chief Physician and Surgeon of Wilderness Physicians, European Union, 43C Żeligowskiego Street, #45, Łódź, Poland 90-644, Email: Abstract Acute Mountain Sickness (AMS); High Altitude Pulmonary Edema (HAPE) and High Altitude Cerebral Edema (HACE). These three disorders, withMountain relatively Sickness, unimportant also smallcalled variationsHigh Altitude seen Sickness, in some isPulmonology specifically aTextbooks, triad of different because disorders, these are inso orderserious, of increasingthey are all seriousness: potentially deadly pulmonary disorders and we will discuss these three major, deadly disorders. Each one, starting with AMS, can progress rapidly to HAPE and then HACE. The two authors of this article have over half a century of high altitude mountaineering experience. They have also alsohad anddisaster still domedicine. have, for Since the lastspring twenty is rapidly years, approaching an NGO, Non-Profit and many Medical “weekend Organization backpackers” (Wilderness will start Physicians going into www.wildernessphysicians. -
Control of Respiration Central Control of Ventilation
Control of Respiration Control of Respiration Bioengineering 6000 CV Physiology Central Control of Ventilation • Goal: maintain sufficient ventilation with minimal energy – Ventilation should match perfusion • Process steps: – Ventilation mechanics + aerodynamics • Points of Regulation – Breathing rate and depth, coughing, swallowing, breath holding – Musculature: very precise control • Sensors: – Chemoreceptors: central and peripheral – Stretch receptors in the lungs, bronchi, and bronchioles • Feedback: – Nerves – Central processor: • Pattern generator of breathing depth/amplitude • Rhythm generator for breathing rate Control of Respiration Bioengineering 6000 CV Physiology Peripheral Chemosensors • Carotid and Aortic bodies • Sensitive to PO2, PsCO2, and pH (CO2 sensitivity may originate in pH) • Responses are coupled • Adapt to CO2 levels • All O2 sensing is here! • Carotid body sensors more sensitive than aortic bodies Control of Respiration Bioengineering 6000 CV Physiology O2 Sensor Details • Glomus cells • K-channel with O2 sensor • O2 opens channel and hyperpolarizes cell • Drop in O2 causes reduction in K current and a depolarization • Resulting Ca2+ influx triggers release of dopamine • Dopamine initiates action potentials in sensory nerve Control of Respiration Bioengineering 6000 CV Physiology Central CO2/pH Chemoreceptors • Sensitive to pH in CSF • CSF poorly buffered • H+ passes poorly through BBB but CO2 passes easily • Blood pH transmitted via CO2 to CSF • Adapt to elevated CO2 levels (reduced pH) by transfer of - - HCO3 -
Outcomes from the 2015 Round Table on Sepsis
The official daily newsletter of the 35th ISICEM Thursday 19 March 2015 Day 3 Outcomes from the 2015 Round Table on sepsis uring the opening session on Tues- day morning, Simon Finfer (Royal North Shore Hospital of Sydney and Sydney Adventist Hospital, Sydney, Australia) was joined by Steven DOpal (Memorial Hospital of Rhode Island, RI, USA) to summarize the major outcomes of the two-day Round Table discussion “This will be a on sepsis. This was a joint conference significant part of our conducted between ISICEM and the Inter- national Sepsis Forum, with representa- research agenda in the tives from every continent highlighting the future – making sure global nature of the problem. Beginning by addressing the current that our patients are state of knowledge in the epidemiology of doing well after they sepsis, Professor Finfer noted that we know leave the hospital.” surprising little, but that obtaining this data will be crucial if any meaningful strategy is Steven Opal to be developed: “To some degree we have data from developed countries, possibly far less than you would expect or think,” he said. “But there are certainly places in, notably, Africa, where we are completely devoid of data.” The reasons for this lack of data can in part be understood by an appreciation of how patient data are currently characterized and treated, with the Global Burden of Disease Project emerging as a central player in generating evidence and guiding is surprising because we believe that sepsis kills one comes into your ICU with community-acquired global health policy. more people than prostate cancer, breast cancer, pneumonia, you treat the pneumonia; maybe they “The only reference to sepsis in these sta- and many other high profile diseases. -
Risk Assessment of Recirculation Systems in Salmonid Hatcheries
Norwegian Scientific Committee for Food Safety (VKM) Doc.no 09/808-Final Risk Assessment of Recirculation Systems in Salmonid Hatcheries Opinion of the Panel on Animal Health and Welfare of the Norwegian Scientific Committee for Food Safety Date: 10.01.12 Doc. no.: 09-808-Final ISBN: 978-82-8259-048-8 VKM Report 2012: 01 1 Norwegian Scientific Committee for Food Safety (VKM) Doc.no 09/808-Final Risk Assessment of Recirculation Systems in Salmonid Hatcheries Brit Hjeltnes (chair of ad hoc group) Grete Bæverfjord Ulf Erikson Stein Mortensen Trond Rosten Peter Østergård 2 Norwegian Scientific Committee for Food Safety (VKM) Doc.no 09/808-Final Contributors Persons working for VKM, either as appointed members of the Committee or as ad hoc experts, do this by virtue of their scientific expertise, not as representatives for their employers. The Civil Services Act instructions on legal competence apply for all work prepared by VKM. Acknowledgements The Norwegian Scientific Committee for Food Safety (Vitenskapskomiteen for mattrygghet, VKM) has appointed an ad hoc group consisting of both VKM members and external experts to answer the request from the Norwegian Food Safety Authority. The members of the ad hoc group are acknowledged for their valuable work on this opinion. The members of the ad hoc group are: VKM members Brit Hjeltnes (Chair), Panel on Animal Health and Welfare Ulf Erikson, Panel on Animal Health and Welfare Stein Mortensen, Panel on Animal Health and Welfare External experts Grete Bæverfjord, Nofima Marin, Sunndalsøra Trond Rosten, SINTEF Fisheries and Aquaculture Peter Østergård, Sp/F Aquamed, Faroe Islands Other contributors to the assessment are Frode Mathisen, Anders Fjellheim and Brit Tørud. -
Absolute Measurements of Cerebral Perfusion and Oxygenation in Rats with Near-Infrared Spectroscopy Bertan Hallacoglu1, Angelo Sassaroli1, Irwin H
Absolute measurements of cerebral perfusion and oxygenation in rats with near-infrared spectroscopy Bertan Hallacoglu1, Angelo Sassaroli1, Irwin H. Rosenberg2, Aron Troen2 and Sergio Fantini1 Tufts University Department of Biomedical Engineering, Medford, MA (1) and USDA Human Nutrition Research Center on Aging, Boston, MA (2) Brain microvascular pathology is a common finding in Alzheimer’s disease and other dementias. However, Figure 2 – Time traces of [Hb], [HbO2], [HbT], StO2 and SaO2 during the hypoxia and hypercapnia protocols 10 and 20 weeks after Figure 3 – Illustration of the differences in animal groups and the extent to which microvascular abnormalities cause or contribute to cognitive impairment is unclear. the start of folate deficient diet (blue and red lines represent the mean values for each dietary group, whereas, dashed lines indicate changes within each group between weeks 10 and 20 in Dietary vascular risk factors, including poor folate status are potentially modifiable predictors of cognitive the range corresponding to ± one standard error from the mean). A first striking result is the consistency of baseline values across cerebral tissue saturation (StO2) and concentration of impairment among older adults. Folate deficiency in rat impairs cognition and causes cerebral animals within a group (control or folate deficient), and the reproducibility of baseline values measured at weeks 10 and 20. hemoglobin ([HbT]), blood concentration of hemoglobin ([HbT]b), microvascular damage, without concomitant neurodegeneration [1]. We hypothesized that folate Absolute brain total hemoglobin concentration ([HbT]) and tissue oxygen saturation (StO2) are significantly reduced by folate and partial blood volume (Vb/Vt) Eq. (1). FD rats have deficiency might result in functional decrements in cerebral oxygen delivery and vascular reactivity. -
Mount Everest's Death Zone
Mount Everest’s Death Zone Climate change and crowds of climbers are making the world’s tallest mountain more dangerous than ever Mara Grunbaum ast year, 73-year-old Tamae Watanabe of Japan became the oldest woman to climb Mount Everest, the world’s tallest mountain. In L 2010, 13-year-old Jordan Romero of California became the youngest to reach the top. All sorts of people of varying abilities scale the massive mountain in Asia these days. That may not be a good thing—for Everest or the climbers. Last year, more than 500 people reached the top of the Himalayan mountain, which towers 8,850 meters (29,035 feet) above sea level. Hundreds more climbed partway up. While it’s a great achievement to scale Everest, it can sometimes cause problems for the climbers and the mountain itself. Everest is changing. Warming Up Why is Everest becoming more dangerous to climb? One reason is changes in its environment. Much of the mountain is covered in huge sheets of ice called glaciers. Lately, warmer temperatures in the region have been melting these glaciers. Some places that used to be covered in ice year-round are now completely ice-free in the summer. Shrinking glaciers put climbers at risk. As glaciers melt, snow, ice, and rock are more likely to tumble down the mountain in huge avalanches. These snowslides can injure or even kill climbers. “As it gets warmer, more debris tends to fall down,” says American climbing guide Freddie Wilkinson. He’s one of a number of people who think that climbing Everest is becoming too risky. -
The Effect of Anemia on the Ventilatory Response to Transient and Steady-State Hypoxia
The effect of anemia on the ventilatory response to transient and steady-state hypoxia. T V Santiago, … , N H Edelman, A P Fishman J Clin Invest. 1975;55(2):410-418. https://doi.org/10.1172/JCI107945. Research Article The effects of anemia upon the ventilatory responses to transient and steady-state hypoxia were studied in unanesthetized goats. Responses to transient hypoxia (inhalation of several breaths of nitrogen) were considered to reflect peripheral chemoreceptor and non-chemoreceptor influences of hypoxia upon ventilatory control. In all goats, severe anemia (hemoglobin 3.1-4.8 g/100ml) markedly heightened the responses to transient hypoxia (from a mean of 0.27 to a mean of 0.75 liter/min/percent fall in SaO2). This phenomenon was substantially reversed by alpha-adrenergic blockade (phenoxybenzamine, 5 mg/kg). In contrast, the ventilatory responses to steady-state hypoxia were unaffected by severe anemia. These data suggest that severe anemia enhances the peripheral chemoreceptor-mediated response to hypoxia through a mechanism involving the alpha-adrenergic system. It also appears that a ventilatory depressant effect of hypoxia which is not mediated by the peripheral chemoreceptors is also enhanced by severe anemia, thereby preventing an increase in the steady-state ventilatory response to hypoxia. Finally, experiments involving variation in oxygen affinity of hemoglobin suggested that O2 tension rather than O2 availability in arterial blood is the major determinant of peripheral chemoreceptor activity. Find the latest version: https://jci.me/107945/pdf The Effect of Anemia on the Ventilatory Response to Transient and Steady-State Hypoxia TEODORO V. SANTIAGO, NORMAN H. -
Respiration the Main Function of the Respiratory System Is Gas Exchange
Respiration The main function of the respiratory system is gas exchange. Gas exchange is achieved through a process called respiration, or breathing. The cardiovascular system and the respiratory system work together to accomplish respiration. External Respiration During external respiration, fresh oxygen from outside the body fills the lungs and alveoli, and carbon dioxide is transported from the body tissues to the lungs. For oxygen to reach the body’s tissues and carbon dioxide to leave the body, gas exchange must occur in the alveolar capillary membrane. The alveoli and the capillaries that surround them make up the alveolar (al-VEE-oh-lar) capillary membrane (Figure 9.5 in the textbook). The alveolar capillary membrane is built for gas exchange, as explained by Fick’s Law. Fick’s Law states that the diffusion of oxygen and carbon dioxide between the capillaries and the alveolar sacs is proportional to the surface area (S.A.) of the lungs, the diffusion constant (D) of each gas, and the difference in partial pressure between each capillary and alveolar sac (P1-P2). According to this law, the diffusion of gases is also inversely related to the thickness of the tissues (T) involved. In simpler terms, thin-walled tissues allow for easier gas exchange. Diffusion = Therefore, oxygen easily diffuses across the membrane of the alveolar sacs and into the capillaries. Carbon dioxide passes from the capillaries into the alveolar sacs, where it can be expelled from the body via the lungs (Figure 9.5). How fast does gas exchange occur in the lungs? Faster than you might think. -
Respiratory Physiology
Physiology Unit 4 RESPIRATORY PHYSIOLOGY Respiraon • External respiraon – ven3laon – gas exchange • Internal respiraon – cellular respiraon – gas exchange • Respiratory Cycle – Inspiraon • Moving atmospheric air into the lungs – Expiraon • Moving air out of the lungs Lungs vs. Balloons • A lung is similar to a balloon in that it resists stretch, tending to collapse almost totally unless held inflated by a pressure difference between its inside and outside • Lungs and the chest have elas3c proper3es Lung Compliance • Compliance – Elas3city – Tendency to recoil – Tendency of an elas3c structure to oppose stretching or distor3on * Resists distension • Surface tension * Resists distension - Surfactant • Reduces surface tension • Increases compliance (makes them easier to stretch) Airway Resistance F = ΔP/R • Same variables that affect resistance in blood vessels – Tube length, tube radius, fric3on – Tube radius most important factor • Airway resistance is so small that small pressure differences produce large volumes of air flow – Average atmosphere-to-alveoli pressure difference is 1 mmHg, but 500 mL of air is moved (%dal volume) – Low pressure and low resistance • Pulmonary 1/10th of systemic vascular resistance Ven3laon • Exchange of air between atmosphere and alveoli • Atmospheric air pressure is 760 mmHg at sea level • Air moves by bulk flow – F = ΔP/R – F = (Palv – Patm)/R Boyle’s Law • Boyle’s law = (P/V) • Pressure of a given quan3ty of gas is inversely propor3onal to volume • An increase in the volume of the container (lungs) decreases the pressure of the gas (air) Ven3laon Mechanics • Lung volume depends on: 1. Transpulmonary pressure (Ptp) • Inside to outside of the lung • Ptp = Palv – Pip • The force that keeps the lungs inflated • Transmural pressure – Across the wall 2.