Pulmonary Ventilation
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Job Hazard Analysis
Identifying and Evaluating Hazards in Research Laboratories Guidelines developed by the Hazards Identification and Evaluation Task Force of the American Chemical Society’s Committee on Chemical Safety Copyright 2013 American Chemical Society Table of Contents FOREWORD ................................................................................................................................................... 3 ACKNOWLEDGEMENTS ................................................................................................................................. 5 Task Force Members ..................................................................................................................................... 6 1. SCOPE AND APPLICATION ..................................................................................................................... 7 2. DEFINITIONS .......................................................................................................................................... 7 3. HAZARDS IDENTIFICATION AND EVALUATION ................................................................................... 10 4. ESTABLISHING ROLES AND RESPONSIBILITIES .................................................................................... 14 5. CHOOSING AND USING A TECHNIQUE FROM THIS GUIDE ................................................................. 17 6. CHANGE CONTROL .............................................................................................................................. 19 7. ASSESSING -
Ventilation Patterns Influence Airway Secretion Movement Marcia S Volpe, Alexander B Adams MPH RRT FAARC, Marcelo B P Amato MD, and John J Marini MD
Original Contributions Ventilation Patterns Influence Airway Secretion Movement Marcia S Volpe, Alexander B Adams MPH RRT FAARC, Marcelo B P Amato MD, and John J Marini MD BACKGROUND: Retention of airway secretions is a common and serious problem in ventilated patients. Treating or avoiding secretion retention with mucus thinning, patient-positioning, airway suctioning, or chest or airway vibration or percussion may provide short-term benefit. METHODS: In a series of laboratory experiments with a test-lung system we examined the role of ventilator settings and lung-impedance on secretion retention and expulsion. Known quantities of a synthetic dye-stained mucus simulant with clinically relevant properties were injected into a transparent tube the diameter of an adult trachea and exposed to various mechanical-ventilation conditions. Mucus- simulant movement was measured with a photodensitometric technique and examined with image- analysis software. We tested 2 mucus-simulant viscosities and various peak flows, inspiratory/ expiratory flow ratios, intrinsic positive end-expiratory pressures, ventilation waveforms, and impedance values. RESULTS: Ventilator settings that produced flow bias had a major effect on mucus movement. Expiratory flow bias associated with intrinsic positive end-expiratory pressure generated by elevated minute ventilation moved mucus toward the airway opening, whereas in- trinsic positive end-expiratory pressure generated by increased airway resistance moved the mucus toward the lungs. Inter-lung transfer of mucus simulant occurred rapidly across the “carinal divider” between interconnected test lungs set to radically different compliances; the mucus moved out of the low-compliance lung and into the high-compliance lung. CONCLUSIONS: The move- ment of mucus simulant was influenced by the ventilation pattern and lung impedance. -
Infections of the Respiratory Tract
F70954-07.qxd 12/10/02 7:36 AM Page 71 Infections of the respiratory 7 tract the nasal hairs and by inertial impaction with mucus- 7.1 Pathogenesis 71 covered surfaces in the posterior nasopharynx (Fig. 11). 7.2 Diagnosis 72 The epiglottis, its closure reflex and the cough reflex all reduce the risk of microorganisms reaching the lower 7.3 Management 72 respiratory tract. Particles small enough to reach the tra- 7.4 Diseases and syndromes 73 chea and bronchi stick to the respiratory mucus lining their walls and are propelled towards the oropharynx 7.5 Organisms 79 by the action of cilia (the ‘mucociliary escalator’). Self-assessment: questions 80 Antimicrobial factors present in respiratory secretions further disable inhaled microorganisms. They include Self-assessment: answers 83 lysozyme, lactoferrin and secretory IgA. Particles in the size range 5–10 µm may penetrate further into the lungs and even reach the alveolar air Overview spaces. Here, alveolar macrophages are available to phagocytose potential pathogens, and if these are overwhelmed neutrophils can be recruited via the This chapter deals with infections of structures that constitute inflammatory response. The defences of the respira- the upper and lower respiratory tract. The general population tory tract are a reflection of its vulnerability to micro- commonly experiences upper respiratory tract infections, bial attack. Acquisition of microbial pathogens is which are often seen in general practice. Lower respiratory tract infections are less common but are more likely to cause serious illness and death. Diagnosis and specific chemotherapy of respiratory tract infections present a particular challenge to both the clinician and the laboratory staff. -
COVID-19 Pneumonia: Different Respiratory Treatment for Different Phenotypes? L
Intensive Care Medicine EDITORIAL Un-edited accepted proof COVID-19 pneumonia: different respiratory treatment for different phenotypes? L. Gattinoni1, D. Chiumello2, P. Caironi3, M. Busana1, F. Romitti1, L. Brazzi4, L. Camporota5 Affiliations: 1Department of Anesthesiology and Intensive Care, Medical University of GöttinGen 4Department of Anesthesia, Intensive Care and Emergency - 'Città della Salute e della Scienza’ Hospital - Turin 5Department of Adult Critical Care, Guy’s and St Thomas’ NHS Foundation Trust, Health Centre for Human and Applied Physiological Sciences - London Corresponding author: Luciano Gattinoni Department of Anesthesiology and Intensive Care, Medical University of Göttingen, Robert-Koch Straße 40, 37075, Göttingen, Germany Conflict of interests: The authors have no conflict of interest to disclose NOTE: This article is the pre-proof author’s accepted version. The final edited version will appear soon on the website of the journal Intensive Care Medicine with the following DOI number: DOI 10.1007/s00134-020-06033-2 1 Gattinoni L. et al. COVID-19 pneumonia: different respiratory treatment for different phenotypes? (2020) Intensive Care Medicine; DOI: 10.1007/s00134-020-06033-2 Intensive Care Medicine EDITORIAL Un-edited accepted proof The Surviving Sepsis CampaiGn panel (ahead of print, DOI: 10.1007/s00134-020-06022-5) recently recommended that “mechanically ventilated patients with COVID-19 should be managed similarly to other patients with acute respiratory failure in the ICU.” Yet, COVID-19 pneumonia [1], despite falling in most of the circumstances under the Berlin definition of ARDS [2], is a specific disease, whose distinctive features are severe hypoxemia often associated with near normal respiratory system compliance (more than 50% of the 150 patients measured by the authors and further confirmed by several colleagues in Northern Italy). -
Human Physiology an Integrated Approach
Gas Exchange and Transport Gas Exchange in the Lungs and Tissues 18 Lower Alveolar P Decreases Oxygen Uptake O2 Diff usion Problems Cause Hypoxia Gas Solubility Aff ects Diff usion Gas Transport in the Blood Hemoglobin Binds to Oxygen Oxygen Binding Obeys the Law of Mass Action Hemoglobin Transports Most Oxygen to the Tissues P Determines Oxygen-Hb Binding O2 Oxygen Binding Is Expressed As a Percentage Several Factors Aff ect Oxygen-Hb Binding Carbon Dioxide Is Transported in Three Ways Regulation of Ventilation Neurons in the Medulla Control Breathing Carbon Dioxide, Oxygen, and pH Infl uence Ventilation Protective Refl exes Guard the Lungs Higher Brain Centers Aff ect Patterns of Ventilation The successful ascent of Everest without supplementary oxygen is one of the great sagas of the 20th century. — John B. West, Climbing with O’s , NOVA Online (www.pbs.org) Background Basics Exchange epithelia pH and buff ers Law of mass action Cerebrospinal fl uid Simple diff usion Autonomic and somatic motor neurons Structure of the brain stem Red blood cells and Giant liposomes hemoglobin of pulmonary Blood-brain barrier surfactant (40X) From Chapter 18 of Human Physiology: An Integrated Approach, Sixth Edition. Dee Unglaub Silverthorn. Copyright © 2013 by Pearson Education, Inc. All rights reserved. 633 Gas Exchange and Transport he book Into Thin Air by Jon Krakauer chronicles an ill- RUNNING PROBLEM fated trek to the top of Mt. Everest. To reach the summit of Mt. Everest, climbers must pass through the “death zone” T High Altitude located at about 8000 meters (over 26,000 ft ). Of the thousands of people who have attempted the summit, only about 2000 have been In 1981 a group of 20 physiologists, physicians, and successful, and more than 185 have died. -
Maximum Expiratory Flow Rates in Induced Bronchoconstriction in Man
Maximum expiratory flow rates in induced bronchoconstriction in man A. Bouhuys, … , B. M. Kim, A. Zapletal J Clin Invest. 1969;48(6):1159-1168. https://doi.org/10.1172/JCI106073. Research Article We evaluated changes of maximum expiratory flow-volume (MEFV) curves and of partial expiratory flow-volume (PEFV) curves caused by bronchoconstrictor drugs and dust, and compared these to the reverse changes induced by a bronchodilator drug in previously bronchoconstricted subjects. Measurements of maximum flow at constant lung inflation (i.e. liters thoracic gas volume) showed larger changes, both after constriction and after dilation, than measurements of peak expiratory flow rate, 1 sec forced expiratory volume and the slope of the effort-independent portion of MEFV curves. Changes of flow rates on PEFV curves (made after inspiration to mid-vital capacity) were usually larger than those of flow rates on MEFV curves (made after inspiration to total lung capacity). The decreased maximum flow rates after constrictor agents are not caused by changes in lung static recoil force and are attributed to narrowing of small airways, i.e., airways which are uncompressed during forced expirations. Changes of maximum expiratory flow rates at constant lung inflation (e.g. 60% of the control total lung capacity) provide an objective and sensitive measurement of changes in airway caliber which remains valid if total lung capacity is altered during treatment. Find the latest version: https://jci.me/106073/pdf Maximum Expiratory Flow Rates in Induced Bronchoconstriction in Man A. Bouiuys, V. R. HuNTr, B. M. Kim, and A. ZAPLETAL From the John B. Pierce Foundation Laboratory and the Yale University School of Medicine, New Haven, Connecticut 06510 A B S T R A C T We evaluated changes of maximum ex- rates are best studied as a function of lung volume. -
Mechanisms of Pulmonary Gas Exchange Abnormalities During Experimental Group B Streptococcal Infusion
003 I -3998/85/1909-0922$02.00/0 PEDIATRIC RESEARCH Vol. 19, No. 9, I985 Copyright 0 1985 International Pediatric Research Foundation, Inc. Printed in (I.S. A. Mechanisms of Pulmonary Gas Exchange Abnormalities during Experimental Group B Streptococcal Infusion GREGORY K. SORENSEN, GREGORY J. REDDING, AND WILLIAM E. TRUOG ABSTRACT. Group B streptococcal sepsis in newborns obtained from GBS (5, 6). Arterial Poz fell by 9 torr in association produces pulmonary arterial hypertension and hypoxemia. with the increase in pulmonary arterial pressure (4). In contrast, The purpose of this study was to investigate the mecha- the neonatal piglet infused with GBS demonstrated both pul- nisms by which hypoxemia occurs. Ten anesthetized, ven- monary arterial hypertension and profound arterial hypoxemia tilated piglets were infused with 2 x lo9 colony forming (7). These results suggest that the neonatal pulmonary vascula- unitstkg of Group B streptococci over a 30-min period. ture may respond to bacteremia differently from that of adults. Pulmonary arterial pressure rose from 14 ? 2.8 to 38 ? The relationship between Ppa and the matching of alveolar 6.7 torr after 20 min of the bacterial infusion (p< 0.01). ventilation and pulmonary perfusion, a major determinant of During the same period, cardiac output fell from 295 to arterial oxygenation during room air breathing (8), has not been 184 ml/kg/min (p< 0.02). Arterial Po2 declined from 97 studied in newborns. The predictable rise in Ppa with an infusion 2 7 to 56 2 11 torr (p< 0.02) and mixed venous Po2 fell of group B streptococcus offers an opportunity to delineate the from 39.6 2 5 to 28 2 8 torr (p< 0.05). -
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. -
CARBON MONOXIDE: the SILENT KILLER Information You Should
CARBON MONOXIDE: THE SILENT KILLER Information You Should Know Carbon monoxide is a silent killer that can lurk within fossil fuel burning household appliances. Many types of equipment and appliances burn different types of fuel to provide heat, cook, generate electricity, power vehicles and various tools, such as chain saws, weed eaters and leaf blowers. When these units operate properly, they use fresh air for combustion and vent or exhaust carbon dioxide. When fresh air is restricted, through improper ventilation, the units create carbon monoxide, which can saturate the air inside the structure. Carbon Monoxide can be lethal when accidentally inhaled in concentrated doses. Such a situation is referred to as carbon monoxide poisoning. This is a serious condition that is a medical emergency that should be taken care of right away. What Is It? Carbon monoxide, often abbreviated as CO, is a gas produced by burning fossil fuel. What makes it such a silent killer is that it is odorless and colorless. It is extremely difficult to detect until the body has inhaled a detrimental amount of the gas, and if inhaled in high concentrations, it can be fatal. Carbon monoxide causes tissue damage by blocking the body’s ability to absorb enough oxygen. In fact, poisoning from this gas is one of the leading causes of unintentional death from poison. Common Sources of CO Kerosene or fuel-based heaters Fireplaces Gasoline powered equipment and generators Charcoal grills Automobile exhaust Portable generators Tobacco smoke Chimneys, furnaces, and boilers Gas water heaters Wood stoves and gas stoves Properly installed and maintained appliances are safe and efficient. -
Oxygenation and Oxygen Therapy
Rules on Oxygen Therapy: Physiology: 1. PO2, SaO2, CaO2 are all related but different. 2. PaO2 is a sensitive and non-specific indicator of the lungs’ ability to exchange gases with the atmosphere. 3. FIO2 is the same at all altitudes 4. Normal PaO2 decreases with age 5. The body does not store oxygen Therapy & Diagnosis: 1. Supplemental O2 is an FIO2 > 21% and is a drug. 2. A reduced PaO2 is a non-specific finding. 3. A normal PaO2 and alveolar-arterial PO2 difference (A-a gradient) do NOT rule out pulmonary embolism. 4. High FIO2 doesn’t affect COPD hypoxic drive 5. A given liter flow rate of nasal O2 does not equal any specific FIO2. 6. Face masks cannot deliver 100% oxygen unless there is a tight seal. 7. No need to humidify if flow of 4 LPM or less Indications for Oxygen Therapy: 1. Hypoxemia 2. Increased work of breathing 3. Increased myocardial work 4. Pulmonary hypertension Delivery Devices: 1. Nasal Cannula a. 1 – 6 LPM b. FIO2 0.24 – 0.44 (approx 4% per liter flow) c. FIO2 decreases as Ve increases 2. Simple Mask a. 5 – 8 LPM b. FIO2 0.35 – 0.55 (approx 4% per liter flow) c. Minimum flow 5 LPM to flush CO2 from mask 3. Venturi Mask a. Variable LPM b. FIO2 0.24 – 0.50 c. Flow and corresponding FIO2 varies by manufacturer 4. Partial Rebreather a. 6 – 10 LPM b. FIO2 0.50 – 0.70 c. Flow must be sufficient to keep reservoir bag from deflating upon inspiration 5. -
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 -
A Cephalopod Approach to Rethinking About the Importance of the Bohr and Haldane Effects·
Pacific Science (1982), vol. 36, no. 3 © 1983 by the University of Hawaii Press. All rights reserved A Cephalopod Approach to Rethinking about the Importance of the Bohr and Haldane Effects· G. LYKKEBOE2 and K. JOHANSEN2 ABSTRACT: This study concerns the physiological implications of the Bohr and Haldane effects and the buffer values in the blood from the cephalopods Nautilus pompilius, Octopus macropus, Sepia latimanus, Nototodarus sloani philippinensis, and Sepioteuthis lessoniana. All species studied except one (Nautilus) have Bohr and Haldane coefficients numerically higher than unity, and the two effects were found to be nearly identical in all cases, in accord with the theoretical prediction of Wyman (1964). However, the functional Haldane coefficient was significantly lower than the Haldane coefficient in two cases (Sepia and Sepioteuthis). Buffer values were highest in the two species with the lowest oxygen requirement (Nautilus and Octopus), whereas the three fast swim mers studied (Nototodarus, Sepia, and Sepioteuthis) display comparatively low buffer values. It is concluded that the large Bohr effects seen in four of the five species may have their primary effect on oxygen loading in the gills. THE OXYGEN AFFINITY ofcephalopod blood is Since the Bohr effect is generally acredited pH-sensitive in all reported cases. However, physiological significance in respiratory blood for no other group of animals does the pH gas transport, variations in it that are related sensitivity ofthe O 2 binding, expressed by the to behavior, habitat, or systemic factors Bohr coefficient (Lllog P50/LlpH), show such a should be easily discernible in cephalopods. large variability between species (P50 denotes The present study compares blood respi the oxygen tension at half02 saturation ofthe ratory properties and discusses their possible blood).