Aerospace Medicine in the UK. David P Gradwell Professor of Aerospace Medicine, KCL. Honorary Consultant Guy s & St.

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1 Aerospace Medicine in the UK David P Gradwell Professor of Aerospace Medicine, KCL. Honorary Consultant Guy s & St.Thomas NHS Trust

2 Scope A little history Some altitude physiology Relationship to clinical Cases Training Educational opportunities Questions?

3 The UK Farnborough King s College London From: ezilon maps

4 RAF Physiological Laboratory

6 AVM Stewart G-loc in WW II

7 RAF InsAtute of AviaAon Medicine, Farnborough

8 Novel ana- G research

9 AVM Peter Howard The Boss when I arrived

10 RAF IAM Hunter T7

12 With thanks to Dr Jon Clark

14 Sea Harrier Engine air test at 40,000 V P B 141 mmhg Spontaneous loss of canopy (1.86 m 2 ) Rapid decompression through 3.5 psi Cabin alatude 22,000 V, P B 321 mmhg Cabin volume 1275 litres Time of decompression by Flieger s equaaon seconds (Haber & Clamann 0.001s)

5 psi Cabin alatude 22,000 V, P B 321 mmhg Cabin volume 1275 litres

16 Al7tude (and pressure rela7ve to sea level) Gas Volume Changes 33,700 feet (1/4) x4 18,000 feet (1/2) x2 8,000 feet (3/4) Sea level 1 X1.25 Boyle s law Volume change is proporaonal to 1/pressure change But change in P A O 2 greater 1

17 Alveolar gases breathing air on ascent

18 SpO2 v P A O2 with alatude

19 Ambient air mmhg Alveolar gas mmhg Nitrogen Oxygen CO2 Water Total pressure = 760 mmhg (101.3kPa) 1kPa = 7.5 mmhg Sea level paraal pressures

20 Ambient air mmhg Alveolar gas mmhg Nitrogen Oxygen CO2 Water Approx paraal pressures at 25,000 V, total pressure = 282 mmhg (37.6 kpa)

21 Oxygen requirements with altitude

23 Canberra PR9

25 Pressure breathing induced syncope during pressure breathing following RD to 60,000 V

26 Eurofighter Typhoon 9Gz > 55,000 V Brakes off to 40,000 V 90 secs

28 Instrumented subject in high performance hypobaric chamber

29 An extract of a trace of respiratory parameters recorded during a rapid decompression from 22,500 V to 60,000 V in 3 seconds with 70mmHg PPB. P abs at base alatude 314 mmhg and 126 mmhg (16.8 kpa) at 60,0000 V.

30 An example trace of alatude, blood pressure, mask cavity pressure and paraal pressure of carbon dioxide in a rapid decompression from 22,500 V to 60,000 V.

31 High alatude PPB Changes in Mean BP 60 Change in mean BP (mmhg) ,000 V 50,000 V 55,000 V 60,000 V ,000 V 50,000 V 60,000 V Control 1:1 1:3 Counter- pressure raaos 1:4 45,000 V 45,000 V 30mmHg PPB 50,000 V 45mmHg PPB 55,000 V 60mmHg PPB 60,000 V 70mmHg PPB

32 Rapid decompression to 60,000 V, PPB 70 mmhg, lower body counter- pressure 1:3

34 Who flies now? Everyone. Annual passengers flown > 3.1 billion (2013) At any Ame 000 s of people in flight In Europe more 2500 aircrav in the air UK > 231 million per annum (2013) (DoT) Rising to > 320 million by 2030

36 Atmosphere: Altitude: 38,000ft Temp: -56 o C Humidity: Very low Cabin: Altitude: 8,000ft Temp: 21 o C Humidity: Low

37 ourtesy - BriAsh Airways

38 Why a concern? Air travel has virtual monopoly over most routes Passengers becoming unwell on flights usually had the condiaon when boarding the aircrav Diversions (1: flights) at best inconvenient, can be expensive and medical services may not match expectaaons. Refused flight can = reduced quality of life or employment Cardiovascular and respiratory diseases common and thus occur among paaents travelling

39 Flight Cabin Environment Cabin alatudes up to 8,000V hypoxia gas expansion Reduced mobility Reduced humidity Circadian dysrhythmia Access to medicaaons

40 Denied flight InfecAous TB (Req. 3 negaave sputum smears on Rx) Current closed pneumothorax Major haemoptysis Requirement for O 2 at sea- level > 4 l/min

41 IN- FLIGHT MEDICAL EVENT RATES 44,000 inflight medical emergencies annually worldwide 1 every 604 flights 16 emergencies per million passengers Peterson D, MarAn- Gill C, Guyeoe F, Tobias A, McCarthy C, Harrington S, Delbridge T & Yealy D (2013). Outcomes of Medical Emergencies on Commercial Airline Flights. NEJM 368,

42 CAUSES OF INFLIGHT MEDICAL EMERGENCIES Syncope & pre- syncope 37.4% Respiratory 12.1% Nausea & vomiang 9.5% Cardiac symptoms + cardiac arrest 8% Seizures 5.8% Peterson D, MarAn- Gill C, Guyeoe F, Tobias A, McCarthy C, Harrington S, Delbridge T & Yealy D (2013). Outcomes of Medical Emergencies on Commercial Airline Flights. NEJM 368,

43 Areas of aeromedical interest Pre- flight medical advice In- flight medical care Variety of paaent groups: Respiratory disease Cardiovascular disease Haematological ENT Post surgery Diurnal effects jet lag, medicaaons

44 Respiratory PaAents Severe COPD (COLD) Asthma RestricAve lung disease (involving hypoxaemia +/- hypercapnia Air travel intolerance with respiratory symptoms Pre- exisang requirement for O 2, CPAP or venalatory support Co- morbidity especially IHD and heart failure Acute respiratory illness inc. recent pneumothorax or acave TB Thorax Suppl

45 Alveolar gases on ascent (healthy subjects, aver 3-5 mins) Sea level P A O 2 = 103mmHg (13.7kPa) 8000 V = 64mmHg (8.5kPa) Sea level P A CO2 = 39mmHg (5.1kPa) 8000 V = 38.5mmHg (5.1kPa) aver 3-5 mins

47 Time course of oxygen tension in pulmonary capillary blood at normal and reduced alveolar oxygen tensions.

48 Aeromedical clinic Lane Fox Respiratory Unit, St Thomas Hospital, London Clinical Provision of specialist advice Audit PaAent access to advice Is it used effecavely? What are the barriers? Research Empirical advice based on consensus guidelines A more formal evidence base strengthens the guidelines

49 PaAent assessment Previous air travel Disease pathology & severity Recent history Spirometry & ABGs SpO 2 at GL (but SpO 2 may drop more than 4% on ascent to 8,000 V) Exercise tolerance Hypoxia amenable to oxygen therapy? Hypoxic challenge: Hypobaric chamber 8,000 V Reduced oxygen breathing gas of 15.1% O 2 May not be equivalent (especially over prolonged periods) (Richard & Koehle 2012)

50 Hypoxic challenge test 15% FiO 2 for 15 minutes PaO 2 > 6.6 kpa (>50 mmhg) Oxygen not required Or S P O 2 =/> 85% PaO 2 < 6.7kPa (<50 mmhg) In flight oxygen(2l/min via Or SPO2 < 85% nasal cannulae)

51 M.Sc AvMed PaAent study aim To invesagate the flight outcomes of paaents requiring supplementary oxygen or non- invasive venalaaon undertaking air travel Rate of inflight medical events CorrelaAon with disease severity LogisAcal issues encountered

52 CONCLUSIONS In- flight events Moderate rate among cohort Pre- Flight Assessment Stability & severity of disease Physician opinion: Primary determinant of management and predictor of inflight event risk Mechanical issues during travel Infrequent & unlikely to compromise clinical stability LogisAcal barriers include; Difficulty obtaining medical insurance Airline/airport regulaaons - equipment carriage & usage

53 Clinical Case 1 65 yr old man Post polio syndrome SpO2 95% on air at sea level FEV <1L Reports desaturaaon in flight to 83% Very quiet on flights SOB when visiang washroom

54 Case 1 hazards Hypoxia Aggravated by exeraon? HCT? Supplemental oxygen? Means of delivery

55 Case 2 26 yr old female Frequent flier Sickle cell disease Anaemia Hb7.5gm/dl Crises temporally related to flying Not used oxygen on board No test Advice?

56 SCALE OF UK AVIATION ACTIVITY 20,000 commercial aircrew 33,000 cabin crew 8,000 military aircrew 3,000 air traffic control officers 25,000 light aircraft pilots 6,000 glider pilots, sport pilots 231 million UK passengers Inbound aeromedically escorted patients 950 military patients in escorted civilian patients 1700 air ambulance civilian patients

57 ESTIMATED CURRENT NUMBERS OF AVIATION AND SPACE MEDICINE PRACTITIONERS 300 Civilian Aeromedical Examiners 130 Aeromedical transportation specialists 30 Military Flight Medical Officers 9 Civil Aviation Authority specialists 8 Airline doctors 6 RAF specialists 4 Commercial research specialists Plus focus for aeromedical nurses, & Biomedical scientists

58 WHY THE NEED FOR AVIATION AND SPACE MEDICINE AS A SPECIALTY?

59 TRAINING PATHWAY FOR AVIATION AND SPACE MEDICINE Selection Selection CST after 72 months minimum FY2 General Medical Training Membership exam ST3 ST4 ST5 ST6 Aviation and Space Medicine Specialty Training DAvMed Research (MSc, PhD, MD) >Maintain' capabilities'and' develop' practice'through' CPD' Enhance'career' and'gain' additional' expertise'through' credentialing'in' special'interest' areas' Develop'depth' of'knowledge' by'learning' through' experience' and'reflecting'on' their'practice' >Move'into' education,' management'and' leadership'roles Workplace-based assessments Training Duration 2 years 4-6 years Rest of Career

60 Map of the UK RAF CAM Henlow Farnborough King s College London CAA Gatwick NATS From: ezilon maps

61 EducaAonal opportuniaes in KCL M.Sc in AviaAon Medicine Diploma in AviaAon Medicine (RCP Faculty of OccupaAonal Medicine European AviaAon Safety Agency Basic AviaAon Medicine Advanced AviaAon Medicine Approved by UK CAA and AAME

62 M.Sc AvMed CVS & RS physiology Library project DAvMed course Research project

63 DAvMed 1 As Post- graduate ceraficate in aeromedical sciences: AlAtude physiology & protecaon AcceleraAon physiology & protecaon AviaAon thermal physiology OrientaAon & disorientaaon Noise & vibraaon AEA IntegraAon MoAon sickness FaAgue Special senses Human performance EjecAon & crash protecaon Space physiology Clinical cardiology, pulmonology, nephrology, neurology, psychiatry, ophthalmology, ENT, O&G, haematology, GI, ID, orthopaedics

64 DAvMed 2 - experiences Hypoxia & pressure breathing European Space Agency Centrifuge Land and sea survival, UHET RAeS AAIB MarAn Baker UK CAA NATS BriAsh Airways (inc. large a/c flight simulator) RAF, Army & RN AvMed Flight

65 AviaAon & Space Medicine high profile increasing clinical requirement crew and pax in aviaaon & space operaaons global educaaonal need UK contribuaon

66 Thank you

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