Transcript Document
“Is There a Doctor on Board?” Steven D Guyton, MD, Maj USAF Medical Emergencies on Commercial Flights • Statistics are unreliable (not all airlines report information) • 30-35 events per million passengers (MedAire,2006) • AHA estimated approx 1000 deaths per year on international commercial flights • 114-316 / yr on US flights (Chicago Tribune 1996) • Since Jan 1, 2003 95 fatalities due to airline accidents (NTSB) and 219 reported fatalities due to medical conditions (MedAire) • Numerous more events not resulting in death Why is the Aircraft Environment Unique? • Confined space with limited resources • Decreased ambient oxygen • Lower atmospheric pressure • Barotrauma, DCS, decompression • Other factors • Motion sickness • Turbulence • Jetlag Resources • Equipment required by FAA is minimal • AED • First Aid Kit • Emergency Medicine Kit • Airlines may have more • Some have added drugs / supplies that have been asked for during previous IFEs • AsMA list of additional recommended medications First-Aid Kit • 1 inch bandages (16) • Noninflatable arm splint • 4 inch bandages (8) • Noninflatable leg splint • 40 inch triangle bandages (5) • 4 inch ace wrap bandages (4) • Antiseptic swabs (20) • Ammonia inhalers (10) • Burn cream – 1/8 oz (6) • 1 inch roll of tape (2) • Scissors Emergency Medical Kit • Sphygmomanometer • D50 (1 amp) • Stethoscope • Epi 1:1000 (2 amps) • Oropharyngeal airways (3) • Diphenhydramine 50mg (2 amps) • Various syringes (4) • Various needles (6) • Nitroglycerin tabs (10) • Set of instructions on basic use of kit Variation is the rule • AsMA panel in 1998 recommended these medications to be onboard all flights in addition to FAA requirements: • • • • • • • • • • • • Acetaminophen Albuterol Aspirin Diazepam Aluminum hydroxide-magnesium carbonate Glucagon Ketorolac Lidocaine Meclizine Oxymetazoline Promethazine Simethicone What do to • When responding to an emergency, ask for the available kits / supplies and take inventory of what you have available to use • Assess victim and determine plan as you normally would, then decide what, if any, additional factors you need to consider • Most airlines have a flight surgeon on standby to help with medical emergencies…this can be a great resource Hypoxia • Review – 4 types • Hypoxic • Decreased ambient oxygen or decreased alveolar absorption • COPD, PE, pneumonia • Hyphemic • Decreased oxygen carried in blood • Anemia, carbon monoxide poisoning • Stagnant • Decreased blood flow • CHF / edema, thromboembolic disease, G-forces • Hystotoxic • Oxygen transported to cells, but it cannot be used properly • Cyanide, alcohol poisoning Alveolar Gas Equation • pAO2 = FIO2 (PATM – pH2O ) – (paCO2 / RQ) • pAO2 = 0.21 (760mmHg – 47mmHg) – (36mmHg/0.8) • pAO2 = 150 – 45 = 105mmHg Cabin Pressure • Less than 8,000 feet • Average is 7,000 feet • B767 6,900 feet • A380 5,000 feet • Correlates to atmospheric pressure of 586mmHg Dalton’s Law • Sum of partial pressures = total pressure • So, if total pressure decreases, partial pressures also decrease • At 7,000 feet cabin altitude: • pAO2 = 0.21 (586mmHg – 47mmHg) – (36mmHg/0.8) • pAO2 = 77.19mmHg More Physiology • pAO2 of 70-80 is still well tolerated in healthy individuals as SaO2 is still >90 • However SAO2 on the oxyhemoglobin dissociation curve drops off dramatically after the 70-80 range Higher risk • Persons with chronic lung and other diseases are more susceptible to low oxygen environment • • • • • COPD CHF Sleep apnea Asthma Smokers • Decreased alveolar absorption • Decreased minute ventilation • Right-shifted curve Hypobarism • Boyle’s Law • Pressure and Volume are inversely related • P1V1 = P2V2 • P1 /P2 = V2/V1 • Why it matters • At 7,000 ft altitude, atmospheric pressure is 586mmHg • 760/586 = 1.3= V2/V1 • Volume increases by 30% case • 32 year old female with left sided chest pain • Involved in a MVC on the way to the airport but did not go to the hospital • Initially only had some mild pain, but since flight began has developed worsening pain in left chest • Over the course of several minutes, she becomes more dyspneic case • Exam: • General – increasing distress • Vitals – tachypneic, tachycardic • Lungs – difficult to auscultate due to ambient engine noise • Chest wall – tender in left lower chest wall directly over ribs • Deviation of trachea to the right began to develop • Diagnosis? case • Tension Pneumothorax! treatment • Oxygen (if available) • Needle Decompression (should be needles available in med kit) • Descend to lower altitude OR… True Story • May 1995, Paula Dixon suffered tension pneumothorax in flight over India • Drs. Wong and Wallace diagnosed her and decompressed using Foley and coat hanger as chest tube and stylet • Brandy used as disinfectant • Water bottled used to create water seal Told pilot not to descend because “Wallace feared that the decompression of the cabin during a descent might make Dixon's condition worse” - Chicago Tribune Cabin Depressurization • Loss of cabin pressure and equalization with altitude of flight • Can be slow, rapid, or explosive • If at cruising altitude, will only have seconds to minutes before loss of consciousness Time of useful consciousness • Average period of time from exposure to oxygen depleted environment to the time when an individual can no longer perform useful functions and is no longer capable of taking proper corrective measures. • Also known as Effective Performance Time • Rapidly decreases with altitude (nonlinear) • Smokers: equal to 3000-5000 ft higher TIME OF USEFUL CONSCIOUSNESS ALTITUDE (FEET) TIME OF USEFUL CONSCIOUSNESS 15000 >30 MIN 18000 20-30 MIN 25000 3-6 MIN 30000 1-3 MIN 35000 30-60 SEC 40000 15-20 SEC 43000 9-15 SEC >50000 6-9 SEC ** TIME MAY BE UP TO 50% LESS IN RAPID DECOMPRESSION What do you do?! • Qantas Flight 30 • July 25, 2008 • Sudden decompression at 29,000 ft • Loud explosion followed by intense rushing air in cabin • Plane made emergent descent to 10,000 ft BOOM! • At 29,000 ft, you now have 1-3 minutes before you pass out… • Unless you smoke, then 30-60 seconds • With a rapid decompression (30-90 seconds or 15-30 seconds) • So, time is valuable…. #1 rule is: DON’T PANIC Put on your Mask…first • Remember, you can’t help anyone else if you’re unconscious Emergency oxygen masks Other issues • DCS • Not common but may be found in recent SCUBA divers • Flying within 12-24 hours of diving is not recommended • Treatment: oxygen, descent, hyperbaric therapy • Barotrauma • Sinuses, ears, teeth • Symptomatic treatment and descent • Motion Sickness • Individual susceptibility • Hydrate, oxygen and increased air flow may help • Antiemetics may be in some kits Bottom Line • Medical Emergencies can occur anywhere • Decreased oxygen and air pressure on airplanes as well as decreased space and resources to use • Ask to see supplies available • Consult with flight surgeon on ground • When in doubt, descend