Question of the Day

The Aerospace Medical Association is dedicated to the science of Aerospace Medicine.  The following questions and answers offer those interested in Aerospace Medicine activities the opportunity to test and expand your Aerospace Medicine knowledge.

Question: Which of the following is NOT included in an examination of the sensorium?

a. Orientation to time, place, and person
b. Retention of three unrelated memory items for five minutes
c. General knowledge
d. Depressed or elated mood
e. Proverb interpretation: concrete or abstract.
Answer: d. Evaluation of the mood, and the appropriateness of the patient's affect (emotional reaction) to material being discussed during the interview, is an important part of the mental status evaluation (MSE). Evaluation of the sensorium is concerned with orientation, recall, retention, memory (short and long-term), calculations, intelligence, ability to abstract, judgment, and insight. Although neurotic or psychotic processes may affect the sensorium, serious deficits are more likely to be associated with organic pathologic processes affecting the brain. REFERENCES: American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 2nd ed. Washington DC: American Psychiatric Assoc, 1968:92. Jacobs JW, et al. Screening for Organic Mental Syndromes in the Medically Ill. Ann Int Med 1977;86:40-46.

Question: Which of the following data is LEAST associated with suicidal potential?

a. The patient is white.
b. The patient is married.
c. The patient is 54.
d. The patient is alcoholic.
Answer: b. Suicide rates are higher in whites with the exception of black males aged 20-35, who have a rate twice that of white males of the same age. Alcoholics are more at risk, as are the single, divorced, and widowed. Risk increases with age. Other risk factors include drug abuse, significant physical illness, a positive family history of suicide, a history of previous attempts, lack of employment, accident proneness, and living alone. Protestant rates are higher than Catholic or Jewish. Women attempt suicide more often; men succeed more often. REFERENCES: Slaby AE, Lieb J, Tancredi LR. Handbook of Psychiatric Emergencies. New York: Medical Examination, 1975:147-151. Jones DR, Katchen MS, Patterson JC, Rea M. Neuropsychiatry in Aerospace Medicine. In: DeHart RL, ed. Fundamentals of Aerospace Medicine, 2nd ed. Baltimore: Williams & Wilkins, 1996:593-642.

Question: Which one of the following is an example of a non-parametric statistical test?

a. Student t-test
b. ANOVA (analysis of variance)
c. Pearson product correlation
d. McNemar test
e. Paired t-test
Answer: d. Non-parametric statistical tests make no assumption regarding the distribution of the observations. Answer (d), McNemar's test is an example of a non-parametric test. Student t-test, ANOVA, Pearson product correlation, and paired t-test are all examples of parametric statistical tests. Parametric statistical tests are used when the data sampled are assumed to follow a particular, typically normal or Gaussian, distribution. REFERENCES: Dawson, Saunder B, Trapp R. Basic and Clinical Biostatistics, 2nd ed. Norwalk: Appleton and Lange, 1994.

Question: The proportionate mortality rate for cancer in the United States during 1978 would be expressed as: the number of deaths from cancer in the United States during 1978 over the total deaths in the United States during 1978. Proportionate mortality is a useful statistic since it tells the epidemiologist:

a. An individuals' risk or probability of developing a disease.
b. The relative importance of a specific cause of death in the total mortality picture.
c. Both a and b
d. Neither a nor b
Answer: b. Proportionate mortality does illustrate the relative importance of a specific cause of death in the total mortality picture. It does not, however, indicate an individuals risk of developing a disease. The proportionate mortality rate does not directly measure the risk or probability of a person in a population dying from a specific disease as does a cause-specific mortality rate. To illustrate its limitations in a simple way, let us assume that there are two countries, A and B, each with a population of one million. Furthermore, country A had a death rate from all causes of death of thirty per 100,000 population in 1975, representing 300 deaths, and country B had an all cause death rate of ten per 100,000 in 1975, representing 100 deaths. Each country had the same death rate from cardiovascular diseases of five per 100,000 representing fifty deaths and a person's risk of dying from cardiovascular disease in each country was the same. The proportionate mortality rates expressed as the per cent of all deaths that were from cardiovascular diseases in each country would then be as follows: Country A: 50/300 =17 per cent Country B: 50/100 = 50 per cent Clearly, this difference in proportionate mortality rates does not reflect the risk of dying from cardiovascular diseases in these countries, which is the same, but the difference in mortality from other causes of death. However, the proportionate mortality rate is useful in indicating, within a population group, the relative importance of specific causes of death in the total mortality picture. This rate aids the epidemiologist in selecting areas for further study and the health administrator in determining priorities for planning purposes. REFERENCES: Lilienfeld AM. Foundations of Epidemiology. New York: Oxford University Press, 1976:59-60.

Question: Which of the following is the most important environmental risk factor for the development of chronic obstructive pulmonary disease (COPD)?

a. Alpha-1-antitrypsin deficiency
b. Airway hyperresponsiveness
c. Smoking
d. Occupational exposures
e. Ambient air pollution
Answer: c. Cigarette smoking accounts for the vast majority of COPD in the United States. Severe alpha-1-antitrypsin deficiency is a significant genetic risk for the development of COPD. Ambient air pollution, a number of occupational exposures (cadmium, gold dust, coal dust) and passive exposure to tobacco smoke have been shown to be independent risk factors for the development of COPD, but none approaches the level of risk associated with active cigarette smoking. REFERENCES: Silverman EK, Speizer FE. Risk Factors for the Development of Chronic Obstructive Pulmonary Disease. Med Clin N Am 1996;80(3):501-522.

Question: Which of the following is NOT recommended to reduce the incidence of coronary artery disease in the United States?

a. Routine screening of men over 45 with exercise ECG
b. Routine screening of men ages 35-65 and women ages 45-65 for high blood cholesterol
c. Routine screening of all children and adults for hypertension
d. Routine counseling of all individuals regarding the benefits of tobacco cessation
e. Routine counseling of all individuals regarding the benefits of regular physical activity
Answer: a. There is insufficient evidence that exercise ECG testing adequately predicts coronary artery disease in asymptomatic individuals to recommend its use as a screening test. At any rate, exercise ECG testing is utilized in the detection of coronary artery disease which is already present, and cannot, therefore, be used to reduce the incidence of the disease in the population. Evidence exists for each of the remaining recommendations, reviewed in detail in the source below, suggesting that they are beneficial in the reduction of coronary artery disease. REFERENCES: Guide to Clinical Preventive Services, 2nd ed. Report of the US Preventive Services Task Force. Baltimore: Williams & Wilkins, 1996.

Question: Which of the following organisms is considered the prime indicator of fecal contamination of water?

a. Escherichia coli
b. Aerobacter aerogenes
c. Clostridium perfringens
d. Chrenothrix
e. Nitrosomonas
Answer: a. The coliform organism is the indicator of fecal contamination in lieu of other pathogens because of the relative numbers involved. While only a few pathogens may be present in the feces of warm blooded animals, there are billions of coliforms. Therefore the presence of this organism gives presumptive evidence of contamination and a high probability of recovery on a sample medium. Further advantages of the coliform group are (1) relative safety during analysis, (2) ease of analysis, and (3) similar survival times as pathogens. REFERENCES: American Waterworks Assn. Water Quality and Treatment. New York: McGraw-Hill, 1971.

Question: The most significant indicator of water pollution is:

a. cyanides.
b. nutrients.
c. dissolved oxygen (DO).
d. chlorinated solvents.
Answer: c. Although all of the above chemicals are important, dissolved oxygen is by far the significant chemical for maintaining aerobic life forms. Most game fish require about 5 mg/L oxygen while some bottom dwellers can survive at 3 mg/L. Other life forms such as the Protista are also sensitive to DO fluctuations. These critical levels can be reached because of man-made or natural causes. Disposal of untreated sewage, for example, will deplete DO when the organic material is oxidized by the life forms. Natural phenomena, such as increased temperatures reducing the oxygen solubility, can also create problems. The result is the same: destruction of the balance of life within the environment. REFERENCES: Chanlett. Environmental Protection. New York: McGraw-Hill, 1973.

Question: Which of the following statements about dust deposition and clearance from the lungs is true?

a. The size of dust particles in the inspired air is immaterial: deposition of particles occurs in random fashion throughout the respiratory system.
b. Dust particles over 20 microns in size are most likely to cause alveolar disease.
c. Dust particles between 0.5 and 5.0 microns are most likely to be harmful to the lung and are consequently most significant in production of pneumoconioses.
d. Dust particles below 0.5 micron in size are most harmful to the lung since they penetrate further into the respiratory passages and are primarily deposited in the alveoli.
Answer: c. Most inhaled particles are deposited on the walls of the respiratory dead space long before the respiratory bronchiole is reached. Nearly all particles of 20 microns and over come into contact with the walls of the bronchi and are deposited there; they are subsequently delivered into the pharynx by the ciliary mechanism. Particles of under 0.5 microns in diameter tend to remain suspended in the air and deposition is minimal. Particles between 0.5 and 5.0 microns are small enough to resist impingement against the walls of the larger air passages, yet are large enough to settle out into the alveoli in as little as 2 to 3 seconds; they are consequently most harmful. REFERENCES: Morgan WK, Seaton A. Occupational Lung Diseases. Philadelphia: Saunders, 1975:22-23.

Question: Which of the following statements about asbestos is true?

a. All types of asbestos produce pulmonary scarring if there has been excessive exposure to the dust.
b. Cancer of the lung occurs among workers who have had excessive exposure to all types of asbestos dust.
c. Cancer of the lung is far more common among asbestos workers who are cigarette smokers than among those who do not smoke.
d. Mesothelioma of the pleura and peritoneum are more common among those exposed to asbestos than among the general population.
e. All of the above.
Answer: e. All are correct. REFERENCES: Morgan WK, Seaton A. Occupational Lung Diseases. Philadelphia: Saunders, 1975:61.

Question: Byssinosis is caused by inhalation of dust from which of the following substances?

a. The fibrous residue of sugar cane
b. Maple wood and bark
c. Cotton, flax, or hemp
d. Cork
e. Grain
Answer: c. Originally the term applied only to disease in workers exposed to cotton dust, but in recent years an identical syndrome has been described in flax and hemp workers. REFERENCES: Zenz C, ed. Occupational Medicine. Chicago: Year Book Medical, 1975:146, 149, 154.

Question: Evidenced-based medicine involves integrating current best evidence with clinical expertise, pathophysiological knowledge and patient preferences in making decisions about the care of individual patients. Evidence-based disease management may encourage effective practice and discourage ineffective practice, thereby improving the process of care while optimizing health outcomes and controlling costs. Nevertheless, many concerns exist about disease management programs. Concern(s) regarding this process include:

a. inclusion of too many disciplines to reach an agreement on appropriate care-plans.
b. feeling of an assembly line approach to medicine.
c. poor patient compliance and disruption of continuity in caring for patients.
d. deterioration in clinician's decision-making skills.
e. c & d
Answer: e. Three major concerns exist about disease management programs: (1) deterioration in clinician's decision-making skills, and (2) suboptimal patient-provider communication and (3) disruption of the continuity of care. However, population based disease management will never obviate the need for individualization, culturally-competent care, elicitation of patient preferences and shared-decision making. Several studies that have examined the use of the multidisciplinary team approach in disease management to optimize care and measure clinical outcomes and resource management have been encouraging, showing cost reduction and higher patient satisfaction. Further studies will be necessary to determine the continued success of these programs. REFERENCES: Ellrodt G, Cook DJ, Lee J, Cho M, Hunt D, Wingarten S. Evidence-Based Disease Management. JAMA 1997 Nov 26;278(20):1687-1692.

Question: Changes in the AIDS case definition in 1993 to include CD4 cells <200 or <14% total lymphocytes resulted in an increase of reported AIDS cases of:

a. 10%
b. 20%
c. 30%
d. 40%
e. 50%
Answer: e. The other answers underestimate the impact that this change had on the reported incidence rate. REFERENCES: Ward JW, Petersen LR, Jaffee HW. Current Trends in the Epidemiology of HIV/AIDS. Philadelphia: Saunders, 1996.

Question: The death rate per 100 million person-miles traveled for motorcycles is more than:

a. 10 times that of cars
b. 25 times that of cars
c. 35 times that of cars
d. 50 times that of cars
e. 75 times that of cars
Answer: c. Motorcycles are a hazardous means of transportation, with the death rate per 100 million person-miles of travel more than 35 times that of cars. Most serious or fatal injuries in motorcyclists involve the head. A large body of literature accumulated over the past decade indicates that helmets reduce but by no means eliminate the risk of head injury. In case studies of hospitalized motorcyclists, the risk of a head injury was 2 to 4 times as high for unhelmeted riders as for those who wore helmets. In a comparison of riders on the same motorcycle, one of whom was helmeted and the other of whom was not, a helmet decreased the risk of fatal head injury by 27%. REFERENCES: Rivera FP, Grossman DC, Cummings P. Injury Prevention: First of Two Parts. N Engl J Med 1997 Aug;337(8):543-548.

Question: The cause of birth defects in children usual is usually unknown. However, prenatal counseling and control of various medical conditions results in considerable reduction in birth defects in selected individuals. All EXCEPT which of the following maternal conditions can be treated prenatally to reduce birth defect rates?

a. Phenylketonuria
b. Diabetes Mellitus
c. Hypothyroidism
d. Folic acid deficiency
e. Hypertension
Answer: e. Hypertension is deleterious to pregnancy, yet not a teratogen. Control of diabetes prior to conception reduces the birth defect rate back to background rates. The teratogenic effect of hyperphenylalaninemia can be avoided by control during pregnancy. Folic acid deficiency is a known factor in neural tube defects. Fetal cretinism can be avoided with thyroid replacement therapy. REFERENCES: Platt LD, et. al. Maternal Phenylketonuria Collaborative Study, Obstetric Aspects, and Outcome: The First 6 Years. Am J Obstet Gynecol 1992:166:1150. Kitzmiller JL, et al. Preconception Care of Diabetes. JAMA 1991;265:731 Czeizel AE, Dudas I. Prevention of the First Occurrence of Neural Tube Defects by Periconceptional Vitamin Supplementation. N Engl J Med 1992;327:1832. Milunsky et al. Multivitamin/Folic Acid Supplementation in Early Pregnancy Reduces the Prevalence of Neural Tube Defects. JAMA 1989;262:2847. Cunningham, et al, eds. William's Obstetrics. Stamford: Appleton and Lange, 1997.

Question: In considering the "dose-response" curve, the following assumptions may be made:

a. The magnitude of the biologic response is a function of the concentration of the agent at the biologic site of action.
b. The concentration at the site of action is a function of the dose administered.
c. The response and the dose are causally related.
d. all of the above are true.
Answer: d. The most fundamental concept in toxicology states that a relationship exists between the dose of an agent and the response that is produced in a biologic system. REFERENCES: Proctor NH, Hughes JP. Chemical Hazards of the Workplace. Philadelphia: Lippincott, 1978:5.

Question: The following statements concerning the use of positive pressure breathing (PPB) for G-protection (PBG) are true EXCEPT:

a. PBG can aggravate arm pain in some seat configurations.
b. PBG can approximately double the duration of G-exposure that a pilot can tolerate.
c. PBG is effective in preventing G-LOC when used without anti-G trousers.
d. Chest counterpressure increases pilot comfort and allows for the use of higher levels of PPB.
Answer: c. The use of PBG without anti-G trousers leads to blood pooling in the extremities and loss of consciousness. It does not prevent G-LOC under these circumstances. REFERENCES: Prior ARJ. Positive Pressure Breathing for G Protection. AGARD AMP Lecture Series on Current Concepts on G-Protection Research and Development, AGARD LS-202.

Question: A 23-year-old male in excellent health flew from sea level to a ski resort at 2,700 m for a week of skiing. He began skiing the day after arrival but as he skied he developed progressive malaise, myalgias, and headache. That evening he noted shortness of breath and later that night developed a cough productive of bloody sputum. On examination the next morning (the second day after arrival) he was found to have a temperature of 38.8C and moist rales were heard diffusely in both lung fields. A chest roentgenogram demonstrated fluffy infiltrates in both lung fields, and a white count was 15,300 with over 85% polymorphonuclear leukocytes. Arterial blood gases on room air demonstrated a PO2 of 82 mm Hg, a PCO2 of 29 mm Hg and a pH of 7.46. What is the most probable diagnosis?

a. Pulmonary infarct with pulmonary edema
b. Bacterial pneumonia
c. High altitude pulmonary edema
d. Congestive heart failure precipitated by exposure to the decreased pO2 at 2,700 m.
Answer: c. High altitude pulmonary edema is seldom seen below 2,500 m but it occurs with increasing frequency with progressively higher altitude exposure. It is more likely to occur in the unacclimatized individual and it has an insidious onset. Symptoms usually begin within 12 to 48 hours after arrival and initially consist of the fatigue, headaches, weakness, nausea and light-headedness as seen in patients with more common acute mountain sickness. The symptoms then progress to include shortness of breath and cough, initially dry but which may then become productive of pink frothy sputum as the pulmonary edema develops. The accompanying elevated temperature and white counts have led to confusion with and treatment for pneumonia or other etiologies for pulmonary edema. In high altitude pulmonary edema, the cornerstone of therapy is immediate descent to a lower altitude. Oxygen and possibly furosemide are adjuncts to the treatment program but do not substitute for descent. Numerous theories have been proposed to explain the development of high altitude pulmonary edema. Hypoxia does cause an increase in pulmonary artery pressure. Patients with high altitude pulmonary edema seem to show more increase in pulmonary artery pressure for a given degree of hypoxia than do individuals resistant to the condition. It has been suggested that, in patients who develop high altitude pulmonary edema, there is associated non-uniform arteriolar vasoconstriction in some areas of the lung fields. This produces excessive blood flow into other portions of the lung with subsequent pulmonary capillary hypertension. The resultant exudation of fluid into the interstitial tissues and alveoli produces the clinical picture of pulmonary edema. Other possible etiologies are provided in the references. REFRENCES: Kleiner JP, Nelson WP. High Altitude Pulmonary Edema: A Rare Disease? JAMA 1975;234(5):491-495. Houston CS. High Altitude Illness: Disease with Protean Manifestations. JAMA 1976;236(19):2193-2195.

Question: A common cause of foodborne illness inflight is due to:

a. delays in serving meals.
b. infected food handlers.
c. contaminated gravies.
d. nonpotable water.
e. improperly cleaned utensils.
Answer: b. Infected food handlers and improper holding temperatures are the two most common causes of foodborne illness inflight. This can be prevented by utilizing an approved inflight kitchen, ensuring a food-handler training program, and conducting periodic inspections. Food should be consumed within four hours of preparation. Most airlines serve meals shortly after takeoff. Although gravy could be a source of contamination, other foods such as roast beef, turkey, and custards, have been implicated. The major airlines of the world today carry only potable water from an approved source. Utensils have not been implicated in inflight food poisoning. REFERENCES: Lathrop GD, Wolfe WH. Role of Aircraft in the Transmission of Disease. In: DeHart RL, ed. Fundamentals of aerospace medicine, 1st ed. Philadelphia: Lea & Febiger, 1985.

Question: As the Flight Surgeon member on the aircraft accident investigation team of an international airline involved in a fatal accident, one of your tasks is to supervise the identification of deceased crewmembers and passengers. You are under considerable pressure by your company and local foreign officials to expedite the identification of the deceased in order for a speedy delivery of remains to the next of kin. Identification may require the use of all available objective information comparing antemortem with postmortem characteristics. Rank, in the order of importance, the objective information necessary for the identification of the remains.

1. Dental records and x-rays.
2. Photographs, ID cards and information, personal effects such as jewelry, clothing, wallet, handbag, etc.
3. Finger and footprint records.
4. Marks, scars, hair.
5. Unique objective physical characteristics such as permanent orthopedic or surgical hardware devices or anatomic changes, deformities, anomalies, skin tattoos, etc.
Answer: 3, 1, 5, 4, 2 Ideally, assistance from forensic pathologists and dentists skilled in identification will be available in the event of the mass disaster situation of a large commercial aircraft accident requiring body identification of many fatalities. In this situation the aviation medicine specialist must, nevertheless, coordinate and manage the timely exchange of identification information from the airline and other sources to the pathologist or dentist. A broad understanding and knowledge of the identification process is therefore, necessary. Positive identification is based on matching antemortem and postmortem information on one or more of the following objective findings: (a) fingerprints and/or infant footprints, (b) dental x-rays or examination records, (c) reasonably unique physical characteristics such as surgical or orthopedic devices or changes, anomalies, deformities, marks and scars. Identification by matching other antemortem and postmortem information is presumptive or tentative. These include less unique physical characteristics such as height, weight, marks, scars and hair; clothing, jewelry and other personal effects and lastly, personal recognition. REFERENCES: Reals WJ. Medical Investigation of Aviation Accidents. Chicago: College of American Pathologists, 1968.

Question: What is a sanitary airport?

a. An airport provided with public rest rooms and pure drinking water.
b. An international airport designated as sanitary by the World Health Organization (WHO).
c. An airport to which the local health authorities can direct foreign aircraft, arriving from areas of the world where vector-borne infectious diseases are known to exist, so that appropriate public health measures can be implemented (isolation of passengers, disinsecting of aircraft, etc.).
d. An airport of entry and departure for international traffic, designated as sanitary by the local health administration, where the formalities for public health, animal and plant quarantine and similar procedures are carried out; which is provided with pure drinking water and wholesome food; which is provided with an effective system for disposal of excrement, refuse, waste water, etc., and which has at its disposal an organized medical service, facilities for isolation and care of infected persons, facilities for efficient disinfection and disinsecting, access to a bacteriological laboratory, and facilities for vaccination against yellow fever.
e. An airport free of Aedes aegypti and the mosquito-vectors of malaria and where active anti-mosquito measures are maintained within a distance of at least 400 meters around the perimeter.
Answer: d. A sanitary airport is an airport, designated as sanitary by the local health administration of a State. The health administration shall designate a number of sanitary airports in its territory, provided they meet the provisions of article 14 and the conditions of paragraph 2 of article 18 of the IHR. These provisions and conditions are listed in answer option (d). Answer (a). This option covers only two of the many conditions and provisions required. Answer (b). WHO is a specialized agency within the United Nations' system; dedicated to the promotion of global health, it establishes inter alia international regulations such as the IHR, but each Member State is responsible for the implementation of these regulations. Consequently, it is for the local health administration, not for the WHO, to designate an airport as sanitary. Answer (c). There are two provisions in the IHR allowing a State to specify certain airports for isolation of passengers: (1) for aircraft carrying persons taking part in periodic mass congregations, and (2) in areas where the vector of yellow fever is present, for aircraft coming from an infected area. These two provisions do not form part of the definition of a sanitary airport. Answer (e). All airports shall be kept free from Aedes aegypti and the mosquito-vectors of malaria and other diseases of epidemiological significance in international traffic. For this purpose active anti-mosquito measures shall be maintained within a protective area extending for a distance of at least 400 metres around the perimeter. This requirement is not one of the specific conditions or provisions for sanitary airports. REFERENCES: International Health Regulations, 3rd annotated ed. Geneva: WHO, 1983. ICPS Environmental Health Criteria 96 - d-Phenothrin. Geneva: WHO, 1990. Annex 9 to the Convention on International Civil Aviation, ICAO Doc. AN 9, 9th ed. Montreal: ICAO, 1990.

Question: The ventilation-perfusion ratio (Va/Qc) of the lungs is greatest in the:

a. left lung.
b. right lung.
c. upper lobes.
d. lower lobes.
Answer: c. "....when man stands, the lower lobes get more blood flow and the upper lobes less..... gravity does not directly change the distribution of air, the decreases in the lower lobes and increases in the upper lobes." REFERENCE: Comroe. Physiology of Respiration, 2nd ed, 1974:177-178.

Question: Man can generally tolerate an appreciable decrease in the ambient barometric pressure because of the:

a. increased blood flow to the brain with hyperventilation.
b. constant percentage of oxygen in the ambient air.
c. shape of the oxygen dissociation curve for hemoglobin.
d. shift toward a state of respiratory alkalosis.
e. decrease in oxygen consumption and metabolic rate.
Answer: c. The explanation of the role of the oxygen dissociation curve in tolerance of decreased barometric pressure involves two facets. First, the shape of the curve, flattening near its top and where Hgb is highly oxygenated, means that Hgb remains significantly saturated until the partial pressure of O2 drops quite low. Secondly, as the partial pressure of O2 drops, hyperventilation is initiated resulting in a respiratory alkalosis. As the blood pH rises, the dissociation curve shifts to the left allowing for a greater percentage of O2 saturation of Hgb at a given O2 partial pressure, i.e., the avidity of Hgb for O2 increases. REFERENCES: Holmstrom FMG. Hypoxia. In: Randel HW, ed. Aerospace Medicine. Baltimore: Williams & Wilkins, 1971:60. Sheffield PJ, Heimbach RD. Respiratory Physiology. In: DeHart RL, ed. Fundamentals of Aerospace Medicine. Baltimore: Williams & Wilkins, 1996:91-92.

Question: A very commonly used maneuver to stop hyperventilation is prolonged breath holding in maximum inspiration. Aviators should be educated to:

a. avoid the maneuver because it can lead to syncope.
b. instruct this maneuver to aircraft passengers who hyperventilate.
c. avoid the maneuver because hypoxia may result.
d. demonstrate the maneuver at the time of physical examination to ensure proper performance.
Answer: a. In sensitive individuals, breath holding has been associated with vagal stimulation, sinus arrest, and syncope. Hyperventilation should be stopped by slow breathing, not by breath holding. REFERENCES: Blackburn LH. The Evaluation of Physiological Syncope in Aviation Personnel. Aerospace Med 1964 Dec:1212-1216.

Question: While studies of job attitudes in air traffic controllers indicate that controllers are, on the whole, more satisfied with their work than employees in most other types of work settings, there are several factors mentioned frequently as sources of dissatisfaction by controllers. These include all but one of the following:

a. high level of responsibility
b. management
c. rotating shifts
d. night work
Answer: a. The high level of responsibility is mentioned frequently as a source of satisfaction and gratification by controllers, not dissatisfaction. Each of the other three items is mentioned frequently as a source of dissatisfaction. REFERENCES: Rose RM, Jenkins CD, Hurst MW. Air Traffic Controller Health Change Study: A Prospective Investigation of Physical, Psychological and Work-Related Changes. FAA Office of Aviation Medicine, 1978, Report No. FAA-AM-78-39. Smith RC. Comparison of the Job Attitudes of Personnel in Three Air Traffic Control Specialties. Aerospace Med 1973;44:918-927. Smith RC, Cobb BB, Collins WE. Attitudes and Motivations of Air Traffic Controllers in Terminal Areas. Aerospace Med 1971;43:1-5.

Question: Which of the following findings may commonly be seen with third-degree heart block?

1. Widened QRS
2. Ventricular rate < 45
3. Absent ventricular rate response to exercise
4. Widened pulse pressure and diminished venous pulsations in the neck
5. Complaints of weakness, dyspnea, fatigue and syncope

a. 1, 2, 3, 4
b. 2, 3, 4, 5
c. 1, 2, 3, 5
d. 1, 2, 4, 5
e. 2,3, 5
Answer: c. Complete heart block (third-degree heart block) is usually due to a lesion distal to the bundle of His, often due to previous myocardial infarction. The QRS is wide. The ventricular rate is slowed to 45 beats per minute or less and does not increase with exercise. The first heart sound is variable in loudness. The pulse pressure is wide and cannon venous pulsations are present in the neck. The patient complains frequently of fatigue, dyspnea, weakness, and often has episodes of syncope. Asystole sometimes causes the syncope (during periods of transition from partial to complete heart block). Prolonged syncope can cause convulsions (Stokes-Adams syndrome) and, if lasting 2-3 minutes, can be fatal. REFERENCES: Krupp MA, Chatton MJ. Current Medical Diagnosis and Treatment. Los Altos: Lange, 1979:229.

Question: A smooth, usually rounded, soft-tissue density demonstrated radiographically in a frontal sinus in which pain was experienced during descent in an aircraft is most likely:

a. mucocele.
b. submucosal hematoma.
c. polyp.
d. pneumatocele.
e. osteoma.
Answer: b. A persisting soft-tissue density in a frontal sinus with which the patient can associate pain during descent in an aircraft is most likely a submucosal hematoma. This was demonstrated by Campbell in dogs in the early 1940's. It is a space-filling phenomenon designed to relieve the relatively negative pressure in the sinus cavity. REFERENCES: Campbell PA. Aerosinusitis. Arch Otolaryngol 1942:35:107. Yarington CT, Hanna HH. Otolaryngology in Aerospace Medicine. In: DeHart RL, ed. Fundamentals of Aerospace Medicine, 2nd ed. Baltimore: Williams & Wilkins, 1996:584.

Question: The most serious aeromedical concern in this pilot is the increased risk for:

a. an hypoglycemic episode.
b. acute pancreatitis.
c. a cerebrovascular accident.
d. a coronary event.
e. renal colic.
Answer: c. With his significant risk for a coronary event, the positive predictive value of an exercise stress test is increased to a level that makes a maximum exercise stress test a worthwhile screening procedure. As the first step in second level screening, a coronary angiogram is too invasive, this may be required if the exercise stress test is positive. REFERENCES: Kruyer WB. Screening for Asymptomatic Coronary Heart Disease. Proceeding of AGARD Conference: Cardiopulmonary Aspects of Aerospace Medicine; 1993; Neuilly-Sur-Seine, France. AGARD-LS-189:2-1 to 2-5.

Question: Testicular cancer is of aeromedical significance because it is common and occurs primarily in the pilot age group; the peak age of occurrence is ________. The decision to give a waiver should be based on the fact that progression occurs first in the central nervous system _____.

a. 20 - 50; very commonly
b. 20 - 35; very commonly
c. 20 - 35; very rarely
d. 35 - 50; very rarely
e. 35 - 50; about half the time
Answer: c. Testicular cancer is the fourth most common malignancy in males, and the most common in the 20-35 year age group (1 in 500). It is associated with over 99% long term survival if found while still confined to the testicle (stage A), and over 95% if confined to the testis and retroperitoneal lymph nodes(stage B). The pattern of spread is generally very predictable, going to the retroperitoneal lymph nodes before hematogenous dissemination to other organs. Pilots with history of testis cancer must receive frequent follow-up studies from their urologist/oncologist, but should be eligible for waiver as recurrent disease would be most likely found prior to central nervous system involvement. Additionally, the flight surgeon is the ideal person to educate the at risk population of young, asymptomatic males on the importance of self testicular examination. REFERENCES: Rowland RG, Donahue JP. Scrotum and Testis in Adult and Pediatric Urology, 2nd ed. In: Gillenwater JH, et al, eds. St. Louis: Mosby-Yearbook, 1991:1565-1598. Singer AJ, Tichler T, Orvieto R, et al. Testicular Carcinoma: A Study of Knowledge, Awareness, and Practice of Testicular Self Examination in Male Soldiers and Military Physicians. Mil Med 1993;158(10): 640-643.

Question: A 28 y/o aircraft mechanic was using a hammer on a metal cotter pin when he experienced a mild pain in his right eye. He continued to feel as if there was something in his eye so he reported to your office. You found his vision to be 20/20, but in addition there was a small area of the cornea which stained with fluorescein. The most appropriate action for you to take is:

a. instill ophthalmic antibiotic drops.
b. patch the eye for 24 hrs.
c. refer the patient to an ophthalmologist.
d. check his intraocular pressure.
e. obtain x-rays.
Answer: c. Refer the patient to an ophthalmologist. Striking metal on metal is a common history given by patients who sustain an intraocular foreign body as a small piece of metal may break off, impacting the eye at sufficient velocity to penetrate. Symptoms and signs may be minimal so a high index of suspicion is warranted in all such cases. While all of the answers above are correct in that they may be performed during the course of a proper examination to rule out an intraocular foreign body and to treat a corneal abrasion, the most appropriate action for you is to refer the patient to an ophthalmologist who has the instrumentation and training necessary to completely evaluate the eye. REFERENCES: Scheie HG, Albert DM. Adler's Textbook of Ophthalmology, 9th ed. Philadelphia: Saunders, 1969:563.

Question: What is the likely explanation for this situation having manifested itself as anxiety about flying?

a. The pilot's motivation to fly was flawed from the beginning of his flying days. The present life stress precipitated an inevitable breakdown in his self-confidence.
b. The pilot is getting older, and one's confidence in one's ability to deal with emergency situations gets shakier as the years pass. His cousin's mishap was the catalyst for his awareness of his aging and vulnerability.
c. The pilot's personality makeup was such that feelings of emotional upset were threatening and had to be repressed. Thus, the anxiety attached itself to another aspect of his life. There may be some symbolic connection, but one may not necessarily have to uncover it.
d. The pilot was so upset that he had subconscious suicidal impulses. His uneasiness about flying was a protective reaction, allowing him to ask for help in handling them.
e. Flying represented an escape from the family situation. He was so conflicted about staying or leaving that the anxiety attached itself to the vehicle that represented his chance to accomplish this escape.
Answer: c. In some instances of acquired fear of flying, choices (a), (d) or (e) may contain a grain of truth, but there is no evidence for any of them in the information provided in this case history. Choice (b) is highly unlikely at this pilot's age, where flying ability is proven, physical capabilities are healthy, motivation has been well-tested, and experience provides a powerful additional safety factor. REFERENCES: Fine PM, Hartman BO. Psychiatric Strengths and Weaknesses of Typical Air Force Pilots. Brooks AFB: USAF School of Aerospace Medicine, SAM Technical Report 68-121, 1968:131-68. Jones DR. Suicide by Aircraft. Aviat Space Environ Med 1977; 48:454-9. Jones DR. Flying and Danger, Joy and Fear. Aviat Space Environ Med 1986; 57;131-6. Jones DR, et al. Neuropsychiatry in Aerospace Medicine. In: DeHart RL. Fundamentals of Aerospace Medicine, 2nd ed. Baltimore: Williams & Wilkins, 1996:610-1.