Thursday, November 1, 2012

Important notes from the Drs. Corner

Anuruddh Kumar Misra, MD, Capt CAP
FACP Board Certified, Internal Medicine
Health Services Medical Officer
Amelia Earhart Senior Squadron 188

Internal Medicine care for Civil Air Patrol, Squadron 188

The duties of the Health Services and Medical Officer to a Search and Rescue squadron such as ours are unique in that there are several specific needs that the squadron at large in broad strokes requires and then there are certain needs specific for pilots.  I will review the topics as I covered for our squadron below:

1.     Dehydration
This a major health hazard for pilots for the primary reason that if a pilot is what is termed “hypovolemic”, they have a significantly increased chance for syncope and other associated symptoms related to inadequate flow to the brain (i.e. visual disturbances, headache, vertigo etcetera).

In order to better rule out prior to the flying, checking vital signs prior to flight with a focus on pulse rate (beats per minute) is useful.  The normal pulse rate is 60-100 beats per minute; this has some degree of variation from person to person.  Hence it is a good idea for pilots to know what a normal pulse rate is for them individually and what a normal range of variance of this value is as well for them as well.

The practical consideration is that if a pilot is hypovolemic and needs to hydrate that this may complicate the flight plans.  The reason for this is obvious -- total expected air time must be taken into consideration because of the need to urinate/expected lead time post hydration must be calibrated accordingly to the planned flight mission.  The best route is oral rehydration for physiological reasons as well as for ease as opposed to parenteral or IV hydration.

It is recommended that pilots and all air crew void their bladders prior to flight regardless the expected duration of flight.

If a pilot is evidenced to be relatively dehydrated (pulse rate in the mid to high 90’s) or outright dehydrated (pulse rate >100) it is advisable that the pilot first not fly and to start rehydration immediately.  The pilot should reassess their pulse rate at a later time if they are more euvolemic (at normal level of hydration) prior to considering flying again.

In summary, dehydrated pilots are at an increased risk for unsafe flights with complications ranging from suboptimal mental sharpness which can result in poor flight control to potentially fatal outcomes.  Checking the vital signs with a focus on pulse rate is an easy first step towards that evaluation and determination.

2.     Medical fitness for flight clearance
Much like DOT (Department of Transport) physicals for the DMV (Department of Motor Vehicles), a medical determination related to medial safety prior to being allowed to fly is an absolute requirement for all pilots.  There a myriad of medical problems that range from relatively benign to severe that can significantly complicate a pilot’s ability to safely operate aircraft.

Some of these conditions are (and are not limited to): Diabetes, Hypertension, Obstructive Sleep Apnea, Seizure disorder and Schizophrenia.  It is essential that all pilot’s have Primary Care Physicians (Internal Medicine, or Family Medicine is best for such situations) who can manage these conditions if present (and others like them) which the Flight Physician can then review prior to issuing flight safety clearance.  It is on the basis of this which will enable her/him to be able to certify that the said pilot is safe to fly by FAA standards.

Documentation of satisfactory control of these medical conditions by the Primary Care Physician is solely the responsibility of the pilot at the time of the visit with the Flight Physician (i.e. providing lab documentation of adequate control of Diabetes or a AHI reading and report from the CPAP machine by the Sleep Medicine Physician to demonstrate the is no risk of drowsiness or sleep attacks while in flight).

3.     OSA (Obstructive Sleep Apnea)
This falls under No. 2, however I take the extra liberties to spell this one our as it is much more prevalent than most are aware of.

OSA was featured in a Reader’s Digest Article recently as one of the “Top 10 diagnoses missed most by Physicians today”.  The reasons for this are simple and have far reaching implications.  Firstly for most patients who have it, they are not acutely aware they have it mainly because they are not knowledgeable about what the symptoms are and how to tie them together to call their Primary Care Physicians attention to it.  Additionally, it generally is a condition which is insidious in onset.  Next just as much, Primary Care Physicians do not as routinely look for or screen for it.  Unlike checking vital signs on visits to the MD wherein in blood pressure (or labs) are checked that may pick up either Hypertension or Diabetes inadvertently or because it is specifically being looked for, without the extra effort to screen for OSA, it is often missed.

One of the most common ways OSA is brought to the forefront of attention of each the patient and that of the Primary Care Physician is that the spouse of the affected individual will report that the concerned individual seems to “stop breathing”, or “fights to breath” or something on these lines which indicates that there is some sort of difficulty breathing when the patient is sleeping.  In my personal experience in my years of practice as an Internist, such a history often is “Exhibit A” as evidence of there being OSA and such an individual has OSA until proven otherwise in my books in my professional medical opinion.

OSA is a major and under reported reason motor vehicle accidents occur and for this reason OSA is just as much a risk factor for pilots crashing.

Common symptoms patients will self report when/if they do will often be: falling asleep when they should otherwise not be falling asleep, accidents secondary to having been sleepy while driving, loud snoring, waking up feeling poorly rested, waking up with gasping, choking or breathing interruptions and even cataplexy.

Common risk factors for OSA are increased abdominal girth (elevated BMI of 35 or greater), increased neck circumference >17 inches for males or >16 inches for females, age > 50, and micrognathia (small jaw).

To screen for OSA, one would use the Epworth Sleepiness Scale which is easily available tool on line.

Occupational medical centers now are mandated to use a “Sleep Evaluation Work Sheet” for DOT physicals as such a medical clearance for drivers concerns the safety of the public as would medical clearance for pilots.

4.     Blood Borne Pathogens
This is an essential topic for our squadron to be knowledgeable regarding because of the fact that our squadron is a search and rescue squadron and as a result can and often will potentially be exposed to blood.  The blood borne pathogens that can be transmitted are HIV, Hepatitis B and Hepatitis C.  Of these, there is a vaccination available only against Hepatitis B which is a series of three shots over a time period of six months.  Vaccination against Hepatitis B is an absolute requirement for first responders of all levels, CAP, USAF or otherwise.

Of the three possible blood borne pathogens that we know today, it is Hepatitis C that is the most likely to transmit as it requires the least number of viral particles in order to infect a possible victim.  Early diagnosis is essential once there is even the remote most possibility of Hepatitis C being contracted.  The potentially infected person must inform their Primary Care Physician as soon as possible to start the battery of blood tests needed to screen for it as it is a potentially fatal condition if contracted and diagnosed too late.  However with early diagnosis and treatment, it is completely curable.  I worked with one of the leading experts the world over today on Hepatitis C during my post-doctoral training period when in Ann Arbor, Michigan.  Hepatitis C is an emerging epidemic and considerably more prevalent than we as a medical community had prior thought was the case, and Dr. Shehab has publish extensively about this.  For the motivated reader and researcher, the numerous publications on Hepatitis C by Dr. Thomas Shehab are available on line at Pub Med or other various search engines such as Google Scholar.

If HIV is suspected to have been transmitted it is crucially important to have this brought to the attention of the individuals Primary Care Physician as starting PEP (Post Exposure Prophylaxis) is pivotal as PEP is time sensitive.  If not started in the correct window period which is measured in hours, the possibility of contracting HIV raises proportionately.

For patients who are immunized against Hepatitis B, it is advisable to check Hepatitis B Antibody titer levels every 5-10 years dependent upon the age and baseline health of the patient as well as the general immune system status.  Booster shots and/or immunization may be indicated and it is crucial to have a sufficient titer level to ensure one is sufficiently protected against potentially contracting Hepatitis B.

Instruction of this topic at the squadron was supplemented with a power point presentation.

5.     First Aid
In following along with the need to protect the First Responder from contracting blood borne pathogens, it is extremely important to know how to glove and protect the First Responder given First Aid from possibly being a victim.

In our First Aid class, I give explicit detail instruction about how to ensure all contact precautions are followed in advance of administrating First Aid.  The same precautions are taught in advance of providing CPR.

Further in First Aid, the class is instructed in the fundamentals of wound care and dressing, splinting wounds, and achieving hemostasis in bleeding patients.  Students are instructed in depth about all the basic aspects of First Aid with first hand teaching by the MD’s, RN’s and Paramedics of the squadron.

6.     CPR/AED
One of the most important aspects of being a First Responder is the ability to confidently deliver CPR and to be able to an AED if needed.

In this class, I first instruct how to do a primary survey in advance of delivering CPR care.  This training is pivotal as the effectiveness of CPR is time sensitive.  Sadly, often times when the point has been arrived at that CPR is needed, as one of the most important professors from my post-doctoral training said it best; “The worst thing that can happen to the person has already happened – just do your best once that point has been arrived at.”

It is important that the CPR provider understand the approach and technique as well as sound command of the algorithm.  This is taught and tested in depth and as with the First Aid class there is practical demonstration as part of the proficiency which must be demonstrated.