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swatsurgeon
07-09-2009, 14:46
What is the military's stance on this interms of time from PTX to ability to fly (in a pressurized aircraft)?
Anyone have printed policy on this?
Thanks

ss

Peregrino
07-09-2009, 21:05
IIRC a DMO or Flight Surgeon can fly a pt. at their discretion. I'll ask at work tomorrow. Somebody ought to know. FWIW, MILAIR can be pressurized to sea level. Not normally done but possible.

Doczilla
07-12-2009, 15:03
From a USAF FS friend....

'zilla

BLUF: 2 weeks following X-ray confirmation of resolution.


First, the pneumothorax should be complete resolved otherwise no flying unless they have a one-way hemlich valve for rotatary or fixed wing aeromedical evacuation. Will this be a passenger or an aviator (since crew members would require a waiver for flying status at least in the USAF don't know about the USA). Also was this a spontaneous event or was there a traumatic cause?

For return to flight status for a patient/passenger then the following should be met:
1) X-ray evidence of complete resolution of the pneumothorax (recall Boyle's law: in flight lower pressure means air will expand thus any unresolved air will enlarge and could cause an acute problem or tension).

2) Most commerical airlines will require 2,4, or 6 weeks after resolution prior to flying depending on if it was spontaneous or traumatic in nature. One case study showed no problem with 14 patients who flew after 14 days whereas 1 of 2 who flew under 14 days had chest pain. These are completely arbitary and not based on scientific evidence. Survey of cardiothoracic surgeons after thoracotomy or mediastinoscopy recommended 7 to 60 days not to fly. Very limited literature on this matter.

3) Also consideration for supplement O2 during flight.



Requirements for aircrew:
Spontaneous pneumothorax is presently disqualifying for an FAA medical certificate of any class unless the situation has been resolved radiographically and there is no underlying lung disease involved. Although the FAA has denied certificates on the basis of SP recurrence without treatment, this stance by the FAA is considered insufficient due to the very high likelihood of a future SP and the subsequent hazard to the airman and the general public.

Both the US Army and the US Navy classify spontaneous pneumothorax as disqualifying for flight duty. Airman are removed from the flight program or denied entry if an attack has occurred within the three year period preceding the medical exam unless it has been surgically corrected with a good prognosis. The United States Air Force is stricter; any history of SP is disqualifying for entry into the flight program. Retention in the USAF program is possible following a single isolated SP episode with full recovery or following successful surgical intervention with six months of grounded observation including hypobaric altitude chamber tests.

NASA currently has the strictest medical guidelines with regard to SP. Entry into the aerospace program is possible if the SP has been surgically corrected and no recurrence has been demonstrated within five years. For retention in the program, the condition must be corrected surgically with six months of observation and no incidence of recurrence.

Confusing enough?

Red Flag 1
07-12-2009, 17:04
What is the military's stance on this interms of time from PTX to ability to fly (in a pressurized aircraft)?
Anyone have printed policy on this?
Thanks

ss

From personal experience, I had an SP in 1970; no surgery required and no recurrence.

Passed USAF flight physical in 1974 with full disclosure. Cleard for both hypo and hyperbaeric chambers. Later worked in both environments with no problems.

The "pressurized cabin" can mean just about anything. For those seeking duties as air crew, it is good to keep in mind that rapid-decompression can happen anytime in any aircraft.

My $.02.

RF 1

DocBrad173
07-20-2009, 14:01
We fly trauma induced pneumo patients all the time on RWAC in Afghanistan; with and without Cx tubes. No big deal. They do fine as long as they are stable.
We try to wait 72 hrs before putting them on FWAC, but we have sent them out the same day from Balad when the beds were full and they did fine.
One of my medics is doing a RWAC evac gig as part of MPT in Bagram right now. I asked him to send me their protocol for you today. Send me your e-mail in a PM and I'll pass it to you when I get it.

Doc Dutch
07-24-2009, 08:52
Swat Surgeon,

This is a great question and one we face a lot in civilian practice on the trauma service. I have had to deal with this question in various trauma centers in the United States and have not found a protocol for allowing patients to fly in any of those centers probably because no one knows. I had asked the trauma.org web server sometime ago without any solid advice having been obtained.

Here is the most likely scenario for us to see such a case and the subsequent concern. A patient is brought to the trauma center. They have been involved in either blunt or penetrating trauma. There is a pneumothorax on either the chest x-ray or CT scan. The patient either gets a chest tube if the pneumothorax is large enough and/or if small enough, we watch it until it resolves and the patient is asymptomatic. After the patient is discharged with adequate treatment of the pneumothorax to resolution, the patient returns to the trauma offices or clinic and asks, "Doc, I have to fly to go on "vacation" or "return home" or "go to a wedding"? Whatever the reason, they have to go somewhere and they want to know if their lung will be okay in a pressurized cabin. Obviously, they do not have a chest tube in, so a Heimlich valve is not an option, and as this is not the scenario for a chest tube already in, it negates the discussion of flying with a chest tube in which is pretty simple as that is the treatment for transferring a patient with a large or symptomatic pneumothorax. Now, if the resolved pneumothorax patient gets in trouble in flight over the US or some ocean, it could be minor, perhaps not even perceptible, or major like a tension pneumothorax. None the less, there is a risk even if most likely very small.

So, many years ago we said 6 to 8 weeks before you could fly. Then I heard 4 weeks. Now, I am hearing 2 weeks with x-ray confirmed resolution of pneumothorax. But what is the data?

I called Luke AFB and Travis AFB and received different answers. At Luke the flight surgeon stated 2 weeks with resolution but could not sight a study and that was for passengers as his flyers were a different story. I asked my commander at Phoenix Sky Harbor, a flight surgeon with the 161st and emergency medicine physician, who stated he thinks two weeks after resolution of the pneumothorax on x-ray. Nonetheless, no concrete data, however, there seems to be a growing consensus that this is the way to go.

So, does anyone know of any research articles done on this topic in any of the literature including trauma, emergency medicine, military medicine, etc? Even case reports would be okay. Anecdotally, I do not have any patients that have reported any problems with the longer waiting periods but as this disrupts their lives they are not generally happy. As there is no hard or fast rules in any of the trauma centers I have been in, this is problematic. I would like to believe that somewhere the USAF, NASA or somebody has done a randomized study.

Any help would be great as I too have thought long about this and what to do in these cases. By the way spontaneous cases are really a different group but we should discuss them too.

Thank you,

Dutch

Red Flag 1
07-24-2009, 12:49
Dutch,

Do you know if the USAF Aerospace Medicine Program is still @ Brooks AFB, Texas? USAF Hyperbaeric Medicine was at the same facility when I attended in 1976. I would like to think the "school solution" may be found @ Brooks.

RF 1

Doc Dutch
07-24-2009, 18:15
RF 1,

Great idea.

Will call them on Monday!

I will get back to you on this topic.

Thanks,

Dutch

olhamada
07-24-2009, 21:04
What is the military's stance on this interms of time from PTX to ability to fly (in a pressurized aircraft)?
Anyone have printed policy on this?
Thanks

ss

Not sure about a pressurized aircraft specifically (but am looking for info), but according to USASAM policy, IAW FM 8-2 regarding aeromedical evac, patients with a PTX may fly with a CT in place and a Heimlich valve. Patients are not to fly within 72 hours of CT removal. A CXR is required within 24 hours of flight on any patient with a recent h/o PTX.

I haven't been able to find a specific policy statement yet addressing waivers for a remote history of PTX, but according to "Clinical Aviation Medicine" by Russell Rayman, 2nd ed., waivers are reasonable for idiopathic spontaneous PTX if there has only been a single episode, there has been complete recovery with full expansion of the lung, PFTs are normal, there is no underlying demonstrable pathology that would predispose to recurrence, and one year has elapsed since the event.

For recurrences, criteria are more stringent and include surgery, altitude chamber evaluation including rapid decompression, PFTs, and 6 months restriction from flying duties. A third event will trigger permanent removal from flying duty.

Blebs and bullae are also waiverable if PFTs are normal, no other associated pulmonary pathology exists, and there is no demonstrable enlargement of the blebs/bullae in lower pressure environments.

Hope this helps!

olhamada
07-24-2009, 21:28
This is from AsMA (Aerospace Medical Association):

Clinical Practice Guideline for SPONTANEOUS PNEUMOTHORAX Developed for the Aerospace Medical Association by their constituent organization American Society of Aerospace Medicine Specialists

Overview: Spontaneous pneumothorax is best defined as “air in the pleural space of nontraumatic cause.” Secondary spontaneous pneumothorax is one that occurs in the presence of underlying parenchymal or airway disease, and for aviation purposes will not be considered further. Primary spontaneous pneumothorax, by default, is one that occurs in the absence of such underlying disease. However, it would be incorrect in such cases to define the lung as normal, since the vast majority proves to have visceral subpleural blebs at thoracoscopy. Primary spontaneous pneumothorax typically peaks in the 16 to 24 year age group, affecting males about 5 to 10 times more frequently than females. Although the incidence in the general population is usually quoted as 9 per 100,000, the real incidence is probably higher. In most large series, 1 to 2% are incidentally found on chest film; since small pneumothoraces resolve themselves within a few days, the odds of identifying an asymptomatic pneumothorax in this way are slim, arguing that the disease is probably more common than thought.

A specific subcategory that deserves mention is catamenial pneumothorax. This is a spontaneous pneumothorax occurring in a female within 48 to 72 hours of the onset of menses. Although these are often ascribed to endometriosis, pleural endometrial implants have been identified in only a third of patients. It is important to question any female with a spontaneous pneumothorax about the timing in relationship to menses, since the initial treatment of catamenial pneumothorax is hormonal. Should the patient fail a trial of contraceptive steroids, this disorder responds well to the same prophylactic surgical treatments described below.

Depending on the size of the pneumothorax, acute treatment may consist of observation, usually combined with oxygen, which hastens resolution; simple aspiration of the air, which is successful about 65% of the time; or catheter or tube thoracostomy. (Since these are usually “air only” pneumothoraces, a small catheter with a Heimlich valve is usually successful, and much more comfortable than a standard chest tube.)

The major issue is recurrence. After an initial pneumothorax, the chance of recurrence is 20 to 50%, a risk that rises after subsequent episodes. (After two pneumothoraces, the risk of a third is 62%; of those who have had three episodes, 83% will have a fourth.) The clinical standard of care for a number of years has been to perform a definitive surgical procedure after the second pneumothorax, but with the availability of thoracoscopic pleurodesis, there are many who feel that surgery is indicated after the first episode, particularly in those who are at high risk because of their occupation or because of travel to remote areas.

Aeromedical Concerns: The most likely symptoms are chest pain and dyspnea, either of which could be incapacitating. In a review by Voge and Anthracite of 112 aviators with spontaneous pneumothorax, 37% admitted they could have been incapacitated had the episode occurred during flight. Overall, seventeen percent of the episodes occurred under operational conditions. Eleven percent actually occurred during flight, although it was unclear how many of these resulted in mission aborts. Of note, another 6% occurred in the altitude chamber, and all but one of those occurred after rapid decompression.

Treatment and Aeromedical Disposition: After complete resolution of a first episode of pneumothorax, the aviator may be returned to flying status without waiver, if a high resolution CT scan demonstrates no pathology, such as blebs or underlying parenchymal disease, which might predispose to recurrence. After a second pneumothorax, or if CT demonstrates residual blebs, waiver may be considered only after definitive surgery to prevent recurrence.

This is pretty much the protocol in the FAA. The civil airman must demonstrate that they have had some definitive treatment after a second pneumothorax.

Experience: The US Air Force Aeromedical Consultation Service has recently reviewed the available literature regarding definitive treatment of spontaneous pneumothorax. Thoracoscopic abrasive pleurodesis appears to be the procedure of choice, with minimal morbidity and a recurrence rate under 5%. Open pleurodesis showed a similar recurrence rate, but is accompanied by greater morbidity. Pleurectomy, whether through thoracotomy or thoracoscopy, offered no additional benefit, at the cost of additional morbidity. Talc poudrage showed variable results, but the only sizable series demonstrated a recurrence rate of 12%. Furthermore, talc administration has some inherent disadvantages, such as the long term risk of pleural fibrosis, which renders its use questionable in the relatively young aviator population. Chemical pleurodesis with tetracycline or similar compounds results in an unacceptable rate of recurrence.

In summary, any form of definitive surgical pleurodesis is acceptable for waiver, but thoracoscopy abrasive pleurodesis appears to offer the best combination of efficacy and minimal morbidity. Chemical pleurodesis with tetracycline compounds is not acceptable for waiver. Talc pleurodesis is not recommended, due to borderline efficacy and the risk of long-term complications.

As of November 2005 the FAA has 303 first-, 198 second-class, and 361 third-class airmen currently issued with a diagnosis of pneumothorax either one or multiple.

References:

Baumann MH, Strange C. Treatment of spontaneous pneumothorax—A more aggressive approach? Chest 1997;112:789-804.

Carter EJ, Ettensohn DB. Catamenial pneumothorax. Chest 1990;98:713-6.

Hopkirk JAC, Pullen MJ, Fraser JR. Pleurodesis: the results of treatment for spontaneous pneumothorax in the Royal Air Force. Aviat Space Environ Med 1993;54(2):158-60.

Melton LJ, Hepper NGG, Offord KP. Incidence of spontaneous pneumothorax in Olmsted County, Minnesota: 1950 to 1974. Am Rev Resp Dis 1979;120:1379-1382.

Mitlehner W, Friedrich M, Dissmann W. Value of computer tomography in the detection of bullae and blebs in patients with primary spontaneous pneumothorax. Respiration 1992;59:221-7.

Paape K, Fry WA. Spontaneous pneumothorax. Chest Surg Clin N AM 1994;4:517-37.

Voge VM, Anthracite R. Spontaneous pneumothorax in the USAF aircrew population: a retrospective study. Aviat Space Environ Med 1986;57:939-49.

August 1, 2006


http://www.asams.org/guidelines/Completed/NEW%20Spontaneous%20pneumothorax.htm

Doc Dutch
07-26-2009, 16:26
Found this today on the internet and will make some calls this week as promised, but in the meantime here is this brief study. Mike Cheatham is a very good physician and he is well respected in the surgical critical care world . . . Dutch

Medline Abstract for Reference 32 of 'Pneumothorax and air travel'

TI Air travel following traumatic pneumothorax: when is it safe?
AU Cheatham ML; Safcsak K
SO Am Surg 1999 Dec;65(12):1160-4.

The safety of air travel for patients sustaining a recent traumatic pneumothorax has long been a subject of debate. The Aerospace Medicine Association has suggested that patients should be able to fly 2 to 3 weeks after radiographic resolution of their pneumothorax. To validate these recommendations, a prospective study was performed. Twelve consecutive patients with recent traumatic pneumothorax expressing a desire to travel by commercial airline were evaluated. Ten patients waited at least 14 days after radiographic resolution of their pneumothorax before air travel (mean, 17.5+/-4.9 days), and all were asymptomatic in-flight. One of two patients who flew earlier than 14 days developed respiratory distress in-flight, with symptoms suggestive of a recurrent pneumothorax. We conclude that commercial air travel appears to be safe 14 days following radiographic resolution of a traumatic pneumothorax.

AD Department of Surgical Education, Orlando Regional Healthcare System, Florida 32806, USA.
PMID 10597066

Doc Dutch
07-26-2009, 16:35
I also found this interesting abstract off the internet from the Radiological Society of North America. We need to remember that the biopsy needles are small compared to a torn lung . . . Dutch

CODE: SSQ05-02
SESSION: Chest (Intervention)
Assessing the Safety of Air Travel Following Lung Biopsy: Interim Analysis



DATE: Thursday, December 04 2008
START TIME: 10:40 AM
END TIME: 10:50 AM

PURPOSE
To report our interim analysis of patients who have traveled by air following lung biopsy.


METHOD AND MATERIALS
IRB approval was granted for this prospective, observational study. Between September 2007 and March 2008, 62 consecutive patients underwent transthoracic lung biopsy followed by air travel. All patients completed a survey questionnaire by telephone within 7-10 business days of their travel date. Questions were designed to determine if patients encountered problems during their flight. Medical records and pertinent imaging studies were also reviewed.


RESULTS
The pneumothorax rate was 34% (21/62) with five of these patients requiring chest tube placement for management. For all patients, the average time following the last chest x-ray obtained after lung biopsy to air travel was 75 hours. For the patients with pneumothorax, the average time following the last chest x-ray obtained after lung biopsy to air travel was 82 hours. It was possible to quantify the size of the pneumothorax on the last chest x-ray obtained before air travel in 81% (17/21) of the patients with pneumothorax. The size of the pneumothorax ranged from <0.5-22%. None of the patients reported any medical events which required emergent in-flight medical attention or flight diversion. All patients felt safe to fly.


CONCLUSION
Most medical guidelines recommend deferring air travel for several weeks following pneumothorax resolution documented by imaging. Our practice has been to allow our post-lung biopsy patients to travel by air following a 24 hour post-biopsy wait period if there were no complications or if there was a small, stable pneumothorax. This preliminary analysis of our results indicates that none of our lung biopsy patients, including those with a small, stable pneumothorax, experienced significant, adverse medical events during air travel.


CLINICAL RELEVANCE/APPLICATION
This study evaluates patients who travel by air following lung biopsy in an attempt to better define a guideline for when it is safe to fly after having sustained a pneumothorax.


QUESTIONS ABOUT THIS EVENT EMAIL:
alda.tam@di.mdacc.tmc.edu

Doc Dutch
07-26-2009, 16:42
I also found this interesting abstract off the internet from the Radiological Society of North America. We need to remember that the biopsy needles are small compared to a torn lung . . . Dutch

CODE: SSQ05-02
SESSION: Chest (Intervention)
Assessing the Safety of Air Travel Following Lung Biopsy: Interim Analysis



DATE: Thursday, December 04 2008
START TIME: 10:40 AM
END TIME: 10:50 AM

PURPOSE
To report our interim analysis of patients who have traveled by air following lung biopsy.


METHOD AND MATERIALS
IRB approval was granted for this prospective, observational study. Between September 2007 and March 2008, 62 consecutive patients underwent transthoracic lung biopsy followed by air travel. All patients completed a survey questionnaire by telephone within 7-10 business days of their travel date. Questions were designed to determine if patients encountered problems during their flight. Medical records and pertinent imaging studies were also reviewed.


RESULTS
The pneumothorax rate was 34% (21/62) with five of these patients requiring chest tube placement for management. For all patients, the average time following the last chest x-ray obtained after lung biopsy to air travel was 75 hours. For the patients with pneumothorax, the average time following the last chest x-ray obtained after lung biopsy to air travel was 82 hours. It was possible to quantify the size of the pneumothorax on the last chest x-ray obtained before air travel in 81% (17/21) of the patients with pneumothorax. The size of the pneumothorax ranged from <0.5-22%. None of the patients reported any medical events which required emergent in-flight medical attention or flight diversion. All patients felt safe to fly.


CONCLUSION
Most medical guidelines recommend deferring air travel for several weeks following pneumothorax resolution documented by imaging. Our practice has been to allow our post-lung biopsy patients to travel by air following a 24 hour post-biopsy wait period if there were no complications or if there was a small, stable pneumothorax. This preliminary analysis of our results indicates that none of our lung biopsy patients, including those with a small, stable pneumothorax, experienced significant, adverse medical events during air travel.


CLINICAL RELEVANCE/APPLICATION
This study evaluates patients who travel by air following lung biopsy in an attempt to better define a guideline for when it is safe to fly after having sustained a pneumothorax.


QUESTIONS ABOUT THIS EVENT EMAIL:
alda.tam@di.mdacc.tmc.edu

Trojan19
10-29-2009, 17:20
Hello Everyone,
I am new to posting here on the forums, and I would like to say thanks for allowing me to be a part of this group. I'm glad to be a part of this community and hope I can use the knowledge many of you possess to enable me to become a smart, hard working, and well informed soldier.

This thread caught my eye as I was doing my research for the positions I hope to one day hold in the USAF: Pararescue or Aerospace Medicine. Long story short, I did very well on my ASVAB (top 95 percentile) and got through MEPS with all 1's on my physical with nothing of consequence happening until I had all my things sent up for a Flying Class III physical.

At this point is where things hit a snag. I had a spontaneous Pneumothorax in mid 2004 and had corrective surgery immediately (video-assisted thoracic surgery/blebectomy with pleurodesis). According to many DOD and Air Force documents, I have had the necessary, and recommended, surgical corrections as well as more than surpassed the 3-year time frame required.

I'm NPS so I'm not sure if this has anything to do with the condition and obtaining a Class III physical. Anyways, I guess I'm just looking for a little guidance and direction on what to do next.

Thanks, Joel

Red Flag 1
10-29-2009, 18:32
Trojan19,

Next would be to follow instructions and fill out your bio.

Re-read this thread.

RF 1

Odd Job
10-29-2009, 19:01
This is a nice summary in an accessible format:

http://www.surgicalcriticalcare.net/Guidelines/air_travel_2009.pdf

There was quite an interesting case to do with plain film vs CT in the radiological detection of a pneumothorax that I was involved with back in 1999. If I can find those images in my collection I might post them if it is deemed worthwhile.

Red Flag 1
10-29-2009, 19:15
This is a nice summary in an accessible format:

http://www.surgicalcriticalcare.net/Guidelines/air_travel_2009.pdf

There was quite an interesting case to do with plain film vs CT in the radiological detection of a pneumothorax that I was involved with back in 1999. If I can find those images in my collection I might post them if it is deemed worthwhile.

Good article.

Would like to see the CT vs CXR films.

Thanks Odd Job!!

RF 1

Trojan19
10-29-2009, 21:25
Got the Bio filled out right this time, didn't notice the save button all the way to the right. Whoops.

Anyways, I've read and reread this thread many times along with countless other documents dealing with SP and the Air Force. I talked with an Air Force Chief today and I was told a CT scan with fine cuts may change the mind of the SG, but nothing is guaranteed (without insurance I obviously can't afford $1000+ for CT scans). He never mentioned if I could still be admitted to the flight program as non-prior service with this prior condition.

Sorry if I'm asking questions that have already been covered, or that are separate from transporting SP patients. I've just had a hard time getting solid answers on whether or not it's even possible for me to serve in a flight job given this prior injury.

Thanks again.

The Reaper
10-29-2009, 21:53
Got the Bio filled out right this time, didn't notice the save button all the way to the right. Whoops.

Anyways, I've read and reread this thread many times along with countless other documents dealing with SP and the Air Force. I talked with an Air Force Chief today and I was told a CT scan with fine cuts may change the mind of the SG, but nothing is guaranteed (without insurance I obviously can't afford $1000+ for CT scans). He never mentioned if I could still be admitted to the flight program as non-prior service with this prior condition.

Sorry if I'm asking questions that have already been covered, or that are separate from transporting SP patients. I've just had a hard time getting solid answers on whether or not it's even possible for me to serve in a flight job given this prior injury.

Thanks again.

You should probably find an AF site and ask there.

This is an Army SF website.

TR

Red Flag 1
10-30-2009, 10:36
Trojan19,

Thanks for the bio. As TR has pointed out, you would likely get closer to a solid answer by dealing direct with the USAF.

Since you are aiming at an aerospace field, I would suggest hooking up with a flight surgeon. You live in Sacramento, and I would suggest giving a call to Flight Medicine at Travis AFB. You probably do not need to talk with a flight surgeon persay; senior NCO's will have the answers to your questions. These are the folks that do flight physicals. My clearances after SP came from the flight surgeons at Brooks AFB, San Antonio, TX. Since you are seeking to join, there may be a way to get the CT's, if needed, at Travis AFB; if you play your cards right.

If you need help hooking up, shoot me a pm.

Best of luck!

RF 1

Odd Job
11-02-2009, 14:05
Red Flag, I found the images. This was a 32 year old male stabbed in the chest, right side antero-laterally. He was stable, no big deal, here is his first CXR (supine):

http://i55.photobucket.com/albums/g154/Odd_Job/CXRSupinesmall.jpg

There was no obvious pneumothorax but we suspected it because of the subcutaneous emphysema you see there on the right. I can't remember what they made of the right middle and lower lobe, just that they didn't like the look of it and were thinking should we put ICD now or wait a bit? Next shot was erect:

http://i55.photobucket.com/albums/g154/Odd_Job/CXRErectsmall.jpg

Still nothing obvious. No pneumo edge. Some 10cm CT cuts showed the pneumo nicely:

http://i55.photobucket.com/albums/g154/Odd_Job/ChestCTsmall.jpg

Because it was mainly anterior there was reduced chance to define the pneumo in this case where the standard X-rays are 90 degrees to the coronal plane. Based on the CT they decided to err on the side of caution and place an ICD.

A historical note: this was Joburg in the late 90s. We had one single slice spiral CT scanner and a heavy workload. It wasn't like the UK and US where you could afford to just scan a guy as a matter of course. With 16,000 adult trauma patients annually, they had to have very strong indications and ambivalent clinical assessments before getting a scan.