Introduction to Aviation Medicine (Virtual) PDF

INTRODUCTION TO AVIATION MEDICINE (Virtual) Date: 18 Jan 2022 Revision no. 01 Aviation Medicine is a branch of occupational Medicine, developed from the need to adapt man to the hostile environment of the air. It is a branch of medicine differs than the other branches of medicine by dealing with N...

INTRODUCTION TO AVIATION MEDICINE (Virtual) Date: 18 Jan 2022 Revision no. 01 Aviation Medicine is a branch of occupational Medicine, developed from the need to adapt man to the hostile environment of the air. It is a branch of medicine differs than the other branches of medicine by dealing with Normals in an abnormal environment while the traditional branches of medicine are dealing with Abnormals in Normal environment. The Aviation Medicine, is occupational medicine because it started with the start of aviation. This was before about 200 years when it has been discovered that the circumstances at high altitude are incompatible with Normal physiology of the human being. History Allah created the human being to live on the earth’s surface (human’s best performance is at sea level). But the human is a challenger creature and kept trying to explore the sky. These trials started before more than one thousand years when Abass bin Fernas was killed when he tried to fly simulating birds. The humankind trials continued. In 1782, Joseph Montgolfier began his first small-scale experiment with hot air balloons which rose to height of 21m. then 305m. in 1783. The First Fatality * The first 2 years of aerial flights were miraculously free of fatal accidents, but this safety record was not to be sustained. In 1787, de Rozier and his passenger died at 1000m altitude when their balloon basket fired. * The first fatal aviation accident was the crash of a Rozière balloon near Wimereux, France, on June 15, 1785, killing the balloon's inventor, Jean-François Pilâtre de Rozier, and the other occupant, Pierre Romain. The first involving a powered aircraft was the crash of a Wright Model A aircraft at Fort Myer, Virginia, in the United States on September 17, 1908, injuring its coinventor and pilot, Orville Wright, and killing the passenger, Signal Corps Lieutenant Thomas Selfridge. *The first powered piloted flight was in 1903. On December 17, 1903, Wilbur and Orville Wright made four brief flights at Kitty Hawk with their first powered aircraft. The Wright brothers had invented the first successful airplane. Physiology at Altitude In 1809, the hazards of high altitude flight became graphically demonstrated when 3 Italians attained an altitude well in excess of 6000m, received frostbite of their hands and feet, experienced vomiting and then lost consciousness. While still conscious, they had difficulty in reading the barometer. The flight ended with the balloon’s descent into the Adriatic sea, and fortunately, the men were rescued. In 1862, two scientists (Glaisher and Coxwell) were the first who described the signs and symptoms of hypoxia at high altitude. So studying the effects of the circumstances of the new environment on the normal physiology of the humankind was, actually, the commencement of Aviation Medicine. They kept developing their knowledge with the development of Aviation. Definition *Aviation Medicine can be defined as: The study of all factors affecting the human body in flight, in health and sickness, and the means by which those flying people may be protected against the potentially harmful effects of the flying abnormal environment. *As per the ICAO definition of Aviation Medicine: “Aviation Medicine is a medical specialty which combined aspects of Preventive, Occupational, Environmental, and Clinical Medicine with the physiology and psychology of man in flight. It is concerned with the health and safety of those who fly, both crews and passengers, as well as the selection and performance of those who hold Aviation licenses”. Aviation Physiology The normal physiology of the human being is affected by 2 factors in Aviation. a. The circumstances of high altitude b. The specification of vehicles used in aviation You can find a well-defined chapter in each textbook of physiology (like Ganong’s review of medical physiology, Guyton and Hall textbook of medical physiology). This chapter is titled “High Altitude Physiology” describing the impacts of high altitude circumstances (low temperature, low barometric pressure, low PO2 on the normal physiology), on the normal physiology. The sky is huge and spacy. Accordingly, the airplanes, spaceships, and rockets are designed with certain specification different than the vehicles used on the ground or on the water surfaces. These specifications, like high speed, acceleration, vibration, and noise can adversely impacts on normal physiology. This is called “Flight Physiology”. Part of what we will study in Aviation Medicine are: • Effects of pressure changes • Effects of low partial pressure of O2 • Thermal stress in aviation • Biodynamics in aviation (effects of acceleration) • Spatial disorientation The first 3 are high altitude physiology The last 2 are flight physiology Scope of Aviation Medicine The scope of Aviation Medicine is very wide-range and the aviation medicine professionals may work in the following titles: • Flight Surgeon • Aviation Medicine Specialist • Aeromedical Examiner Through these titles, the Aviation Medicine professionals can perform the following: a. Healthcare of Aircrew Members i. Selection and medical certification ii. Health maintenance iii. Treatment of aviation related health disorders iv. Training and education ICAO It is a huge organization belong to the UN established after Chicago convention in 1944. It concerned with maintain International flight safety through creating regulations for aviation safety, security, efficiency and regularity and environmental protection. The organization also regulates operating practices and procedures covering the technical field of aviation. All countries are contracting states with ICAO & adopt its regulations. Part of these regulations are the SARPs. Selection should be conducted as per the International SARPs that established by the ICAO (Annex 1) and adopted by the National Civil Aviation Authorities of each country. In UAE, it is CAR MED. • The following personnel have to undergo the selection procedures: a) Flight Crew - Private Pilot - Commercial Pilot - Airline Transport Pilot - Glider Pilot & LSA - Free Balloon Pilot - Flight Navigator - Flight Engineer - Cabin Crew (not for all authorities) b) Other personnel - Aircraft Maintenance - Air Traffic Controller *A person shall not act as a flight crew member of an A/C unless a valid license is held showing his compliance with the specifications of SARP’s that are appropriate to the duties to be performed by that person. *Nobody can be engaged in international air operation without carrying their appropriate license. ICAO Annex 1 *ICAO convention held in Chicago 1944. *18 Annexes to this convention were published. *Annex one titled (Personnel Licensing) *The purpose of this Annex is to ensure that the license holder’s competence, skills, and training will remain the essential guarantee for efficient and safe operations. * Annex 1 contains Standards and Recommended Practices adopted by the International Civil Aviation Organization as the minimum standards for personnel licensing. * The Annex is applicable to all applicants for and, on renewal, to all holders of the licenses and ratings specified. * Chapter 5 of the Annex contains the medical requirements for all the medical classes. b. Healthcare of Passengers i. Assessment for travel fitness ii. Treatment of aviation related health disorder iii. Medical advices i. Assessment for travel fitness *In commercial flights, the passengers should have a certain level of fitness to cope with the flight stresses that encountered even the pressurized air carriers. *Through the international flights, there are some health conditions that are not allowed to travel with commercial airlines, these conditions are usually considered unacceptable for air travel *Each individual case should be assessed on its own merits, and take into account whether the passenger is required to be accompanied by a medical escort. However, as a general guide the following conditions are usually considered unacceptable for air travel: Conditions usually considered unacceptable for air travel: • • • • Severe cases of anaemia. Severe cases of middle ear infections (otitis media). Acute, contagious or communicable diseases. Those suffering from congestive cardiac failure or other cyanotic conditions which aren’t fully controlled. • Uncomplicated myocardial infarctions (MI) within two weeks of onset, or complicated MIs within six weeks of onset. • Those suffering from severe respiratory diseases or recent pneumothorax. • Those with gastrointestinal lesions which may cause hematemesis, melaena or intestinal obstruction. • Post-operative cases: - Within 10 days of simple abdominal operations - Within 21 days of chest or invasive eye surgery (not including laser surgery). • Jaw or jawbone fractures with fixed wiring of the jaw (unless medically escorted). • Unstable mental illnesses without escort and suitable medication for the journey. • Uncontrolled seizures (unless medically escorted). • Uncomplicated single pregnancies beyond the end of the 36th week or multiple pregnancies beyond end of the 32nd week. • Infants within seven days of birth. • Those who have introduced air to body cavities for diagnostic or therapeutic purposes within the previous seven days. Jet lag A physiological condition that results from disturbance of the body’s circadian rhythm caused by trans-meridian travels The main manifestation is sleep disorder & fatigue It may last several days before the traveler can readjust his biological clock to the new time zone *The recovery period of 1 day per time zone crossed , is the estimated approximate time for recovery *Called Jet lag because before the arrival of the Jet aircraft , it was uncommon to travel far & fast enough to cause the desynchronosis *Traveling east causing more problems than traveling west because the body clock has to be advanced which is more difficult than delaying it. Most people have circadian rhythm that is longer 24 h., so lengthening a “less troublesome than shortening it” Management (Light is the strongest stimulus for realigning the sleepwake light-dark cycles & the key to quick adaptation is timed light exposure -- Traveling East …… it is desirable to avoid light in the morning --Traveling West …… it is sufficient to seek exposure to light during the day & avoid it at night. c. Preventive Medicine i. Control of aviation transmissible diseases ii. Supervision of airplane uplifting meals and catering onboard commercial flights iii. Water supply d. Occupation Medicine As an example, Implementation of airport’s hearing conservation program. e. Ergonomics (Human Factors) Ergonomics is the scientific discipline concerned with the understanding of the interactions between human and other elements of a system, and the profession that applies theory, principles, data, and methods to design in order to optimize human well-being and overall system performance. *In cockpit design, all the flight deck environment, the dimensions of the flight deck and the content of the flight deck (the number of crew members, the amount of avionics and of controls and display), in all of these, the physiological requirements should be considered. • The primary physiological design requirement, is to ensure that the pilot is able to survive and operate efficiently in his working environment. • The threshold of noise intensity exposure (the noise level should be limited to 70dB). • Anthropometry and the dimensions of the cockpit. • Visual limitation should be considered in design of lightening of the cockpit. Example, the rods sensitivity to bright light made the designers to consider low intensity lights in the lightening of cockpit. f. Operational Health Services i. Aeromedical evacuation ii. SAR (search and rescue) g. Accident Investigation Although the transportation by aviation is considered as the safest way of transportation, fatality is usually associated with aviation accidents * Accident Investigation team * Assess the human factor in the accident & ictims Identification. Aviation Accident & Incident *An aviation Accident is defined by the Convention on International Civil Aviation Annex 13 as an occurrence associated with the operation of an aircraft, which takes place from the time any person boards the aircraft with the intention of flight until all such persons have disembarked, and in which a) a person is fatally or seriously injured, b) the aircraft sustains significant damage or structural failure, or c) the aircraft goes missing or becomes completely inaccessible. *Annex 13 defines an aviation Incident as an occurrence, other than an accident, associated with the operation of an aircraft that affects or could affect the safety of operation. Aeromedical Training Tools 1. Altitude Chamber (Hypobaric or Decompression chamber) 2. Hyperbaric Chamber 3. Gyrolab 4. Human centrifuge 5. Motion sickness Trainer 6. Ejection seat trainer ICAO Aviation Medicine (MED) Section * ICAO sets Standards and Recommended Practices (SARPs) for international civil aviation in accordance with the consensus views of its 193 Contracting States in order to achieve an acceptable level of flight safety. * The SARPs concerning medical provisions on medical fitness requirements of licence holders are contained in Annex 1 to the Convention on International Civil Aviation. * The SARPS concerning the prevention and management of communicable diseases (CAPSCA) in aviation are contained in ICAO Annexes 6, 9, 11, 14, 18 and the PANS-ATM. The principal responsibilities of the ICAO Aviation Medicine Section are: 1• Ensuring the medical provisions in Annex 1 remain up-to-date; 2• Management of the programme “Collaborative Arrangement for the Prevention and Management of public health events in Civil Aviation” (CAPSCA); 3• Providing guidance to medical examiners and medical assessors concerning the interpretation and implementation of medical provisions. Written guidance is available free of charge in the Manual of Civil Aviation Medicine (Doc 8984); 4• Editorial responsibility for the Manual on Prevention of Problematic Use of Substances in the Aviation Workplace (Doc 9654) and the Manual on Laser Emitters and Flight Safety (Doc 9815), which are available for purchase from the ICAO Online Store; 5• Development of appropriate SARPs and guidance material to facilitate and harmonize preparedness planning for public health events that impact aviation such as serious communicable diseases, radio-nuclear and chemical accidents; 6• Provision of guidance to licensing authorities in Contracting States on medical provisions; 7• Conducting and participating in regional seminars on aviation medicine and preparedness planning, conducting ICAO educational sessions at international aviation medicine scientific meetings, and presenting papers at such meetings.