History: Vintage Medical Devices

Did Those Old Medical Devices Really Work?
by
Louis Farah

Many years ago I attended a Los Angeles County paramedic update class. These are a part of my yearly continuing education that introduces new medical procedures for field use and/or any changes to county protocols.
Sitting with a bunch of old salts like myself that have been playing the paramedic game since the 1970′s, we marveled at the number of changes we’ve seen in medical care throughout the years.

At one time my paramedic unit carried five different pain medications, each used for something different; Demerol for muscle pain, Morphine for chest pain, Valium and Phenobarbital for seizures and Talwin for fractures.
We carried five different IV solutions and a variety of drugs used for drips. Paramedic units in Los Angeles County were stocked with virtually everything found in an emergency room because our paramedic program was still considered a “pilot program” that allowed emergency room physicians the latitude to order any medical procedure they felt was necessary to save a patient’s life.

The Wedworth-Townsend Act opened the door for paramedic programs throughout California. Unfortunately there were no standardized protocols for treatment. Each county had the ability to design and develop their own programs, and as a result, paramedic field treatment was as varied as the number of counties with paramedics.

However, one aspect of paramedic care was constant: The equipment we used.

Long before the advent of paramedics, ambulance services were using virtually the same emergency equipment made by a handful of manufacturers.

Early Resuscitators

Perhaps the most advanced piece of equipment in the early days of EMS was the use and delivery of supplemental oxygen via the resuscitator. Vintage equipment such as the old Emerson units used large and heavy tanks to power a device that forced air into the lungs of a patient. The standard procedure for anyone having breathing difficulties was the practice of putting a mask on their face with a tight seal to inflate the lungs.
Unfortunately, few of these people survived because the underlying cause of the medical emergency wasn’t alleviated by simply forcing oxygen into the lungs. However, for drowning victims and those overcome by smoke, the benefits far outweighed the negatives, so these units found a home on ambulances across the nation.

These resuscitators definitely had their limitations: They were big, heavy and bulky; It took two strong men to transport the unit from the ambulance to the patient; and they “cycled”.

Cycling was a design built into the system. To prevent damage to the lungs from over-inflation, once the resuscitator reached 40 pounds per-square-inch in pressure, the unit stopped pumping oxygen.
For those that suffered from chronic obstructive pulmonary disease, 40 pounds of pressure wasn’t enough to fill the lungs with air. As a result, for those patients with any type of obstructive lung disease, the Emerson resuscitator did more harm than good.

By the 1950′s, the theory of rescue breathing was making huge advancements. Although CPR had yet to be applied in a field setting, the medical community was starting to embrace the practice by numerous methods of rescue breathing including the use of the old arm-lift method, and eventually mouth-to-mouth rescue breathing.

With the evolution of the manual resuscitator, one of the most famous and well-known pieces of oxygen equipment came into vogue:
The green-cased E&J “Lifeport” oxygen resuscitator.

The good old E&J became the standard of the industry. Both the Los Angeles City and County Fire Departments used it as standard equipment on all of their apparatus, as did most other fire departments across the country. It too operated much like the Emerson unit, but it was much smaller and utilized lightweight “D” sized oxygen cylinders.

Both the Emerson and E&J resuscitators depended on the patient’s ability to breath in the oxygen in order to be beneficial. With the limitation of the cycling feature, those needing rescue breathing benefited little from the devices.

Perhaps the greatest advancement in the delivery of oxygen was the demand valve. At the press of a button, high-flow oxygen could be forced into the lungs without the worry of the device cycling, and thus, discontinuing the flow of oxygen into the lungs.

For rescue breathing on the go, the formidable ambu-bag was introduced in the 1960′s to ventilate a patient in distress. With the advent of cardio-pulmonary resuscitation, two rescuers could perform chest compressions and provide adequate oxygenation to a person with reasonable success.
The ambu-bag is used today as the primary mode of delivering rescue breathing to a patient outside of the hospital emergency room. The most widely used in-house device remains the ventilator, which can deliver a variety of oxygen concentrations and ventilation pressures and settings. The 1980′s saw the discontinuance of the demand valve resuscitator because of concerns associated with possible over-inflation of the lungs. Without a “pop-off” valve to prevent inflation pressure of above 40 pounds per-square-inch, the medical community seems to be more at ease with the ambu-bag that has that capability.

Even with the advancements of airway control with such devices as the endotracheal tube, the ambu-bag has undergone design changes to improve the delivery of oxygen into the lungs. Today’s ambu-bags have long connecting reservoir tubes to ensure 100% oxygen concentrations in the bag prior to deflation; New snap-on filters have color indicators to confirm the exchange of inhaled oxygen and exhaled carbon dioxide.

Although the old Emerson and E&J resuscitators are a huge part of EMS history and are standard props in our professional vehicles, their usefulness in today’s modern world of medicine has fallen by the wayside. However, before the advancement of emergency medical care, they were the standard of the industry.

Suction Devices

Just as important as delivering oxygen to a patient’s lungs was the establishment of a clear airway to facilitate the delivery of the oxygen to a patient’s lungs.

Perhaps the earliest device for clearing an airway was the simple bulb syringe. In fact, the bulb syringe is used today to clear the airway of an infant during delivery and a larger syringe can be used to clear fluids from the mouth and throat from most adults. However, when a larger volume of debris needs to be removed, the mighty Rico suction unit has become standard equipment in nearly all ambulances operating in this country.

The Rico suction unit gained popularity in the 1960′s because of the pressure generated by the suction unit and the large canister used to collect the secretions provided a much improved way of clearing a patient’s airway in an emergency. Whether the obstruction was blood or vomit, the Rico unit had the power and the capacity to handle the job.

There have been two units used in the field. The first was powered by manual suction created from the engine manifold of the ambulance being used. A hose was connected to the intake manifold and routed to the suction unit itself. Using the suction power of the engine, debris could be suctioned up into the catch canister. The power of the suction depended on the amount of suction generated by the ambulance’s intake manifold, which varied from ambulance to ambulance.

However, the cost of the suction unit was relatively cheap because early models did not have an independent motor that powered the unit. The mechanics were simple: Hook one end of the suction hose to the ambulance’s engine, hook the other end of the hose to the suction unit, and you were in business.

The modern Rico suction unit did away with the use of the engine’s manifold as the main source of suction in favor of a new unit that featured it’s own suction motor. The pressure generated by the motor was more consistent and could be regulated to meet the needs of individual patient requirements. Today, a suction unit is standard equipment in every ambulance manufactured in America.

As time went on, other companies entered the market with lighter and more compact devices. The Laedal Company produced a fine line of portable suction units that were powered by rechargeable batteries. Soon they became a standard as well. With the vast acceptance of the Laedal units, Rico soon concentrated their efforts on vehicle-based suction units while Laedal took over the portable market.

Entering the Modern Age of Paramedics

Basic life support devices such as oxygen tanks, resuscitators, ambu-bags and suction units have changed little prior to 1969. Yes, some improvements were made to make them more efficient. But the most significant evolution in the field of emergency medical services was the development of the paramedic.

No longer would citizens have to depend on a fast ride at break-neck speed to the nearest hospital to receive comprehensive emergency medical care. That advanced level of medical care would be brought to the scene of an emergency and the same high tech equipment used in the hospital would be used as well.

Perhaps the two most important tools were the portable heart monitor/defibrillator developed by the Datascope Corporation and the portable radio designed by Biocom.

Together, these two pieces of equipment brought those who had died back to life, or prevented one from dying.

Those experiencing cardiac arrest outside of an emergency room were doomed to a virtual death sentence. Without quick defibrillation, they would pass from “clinical death” to “biological death” with no possible chance for survival.

The use of the Datascope heart monitor/defibrillator, coupled with the proper cardiac drugs and the delivery of a counter-shock in a timely manner could convert a fatal heart rhythm into a normal heartbeat and save countless lives.

The use of the heart monitor/defibrillator with the patient’s electrocardiogram being transmitted to the hospital via the Biocom radio put a paramedic in direct contact with an emergency room physician. The physician could see the heart rhythm the paramedic was seeing in the field, and timely treatment was initiated to prevent a potentially-fatal heart rhythms from occurring.

The impact was immediate.

Prior to the introduction of paramedics, nearly 90% of all cardiac cases never made it to the hospital alive. A heart attack outside of a hospital meant certain death. Today, over 90% of all heart related patients not only make it to the hospital alive, but they survive and go on to live productive lives.

Most cardiac monitor/defibrillators today are standard tools in treating a variety of cardiac emergencies. Developments during the last thirty years include the use of twelve leads to view the entire heart from front to back, and heart pacing capabilities for those patients in acute heart failure. Some units, such as the Life Pack 12, even record voice conversation at the scene of the emergency for documentation at a later time.

Perhaps the most important piece of equipment was (and still is) the radio used by the paramedic base station hospital that receives the assessment and report from the paramedics and relays back medical treatment to the paramedics in the field.

The base station radio not only receives voice transmissions from paramedic crews, but receives the patient’s EKG rhythm as well. Advanced life support treatment is much more sophisticated than ever before and current protocols require much more documentation of medical conditions before and after treating the patient.

At the time of their use, these medical devices were considered state-of-the-art and were widely used. Just as the ambulance has improved in performance, style and convenience, medical devices have steadily improved to meet the new protocols of emergency medical care in a pre-hospital setting.

For those of us that have been involved in the field of emergency medical services since the 1970′s, the changes have been astonishing. We are doing medical procedures and using equipment that is even more advanced than ever before.

As to the question of did these devices actually work?

Yes, indeed they did!

Louis Farah is a professional car collector and historian as well as being an active Paramedic in the Los Angeles area.

Federal Electronic Sirens

Federal’s ‘Director’ and ‘Interceptor’ Electronic Sirens

By: Leslie Erlich

So you found a 1970 Superior/Cadillac 54′ high headroom ambulance that is rusting away and you want to restore it to the way it was when it was new.   The beacon and siren are long gone but you have a idea of what type of warning equipment it had when it was first put into service.   Beacons are fairly easy to find – either a Federal 17 series or 184 series will do.  But what about the siren?  Should you go mechanical or electronic?  According to the 1970 Superior catalogue, there were three mechanical siren options: A Federal Q, a Federal C6, or a B&M Super Chief.   As far as electronic sirens go, only the siren speakers are illustrated in the catalogue: a Federal CP25, CJ24, SA24, and CJ184 speaker/light. But if the speakers were Federal, chances are the siren would have been a Federal Director or Interceptor.

If you choose to go with an electronic siren, the Director and Interceptor models are by far the most recognizable among the old Federal electronics, particularly the ‘brown face’ Director and the ‘blue face’ Interceptor.  The brown face and blue face versions were in production for about twenty years, and on the surface they look pretty much the same regardless of when they were made.   To the uneducated observer, a siren is a siren is a siren.  But I will argue that surface appearance alone is not a valid indicator of period correctness.  The Director and Interceptor sirens underwent several design changes throughout the course of production, and in my research I have found that the sound of the siren is the best indicator of period correctness.

PA5 and PA10

The very first Director and Interceptor sirens were the PA5 and PA10, and they only vaguely resembled their brown and blue faced cousins.  The Director was intended to be the ‘economy’ model while the Interceptor would be the ‘deluxe’ model.   The most significant features about both sirens are that the Director has a wired-in microphone and screw terminals for power/speaker/radio connection, while the Interceptor has an optional detachable microphone and multi-pin plug connectors for the radio, speakers, and power supply.   The PA5 (Director) and PA10 (Interceptor) had black control panels and grey plastic knobs, and they were both capable of producing the standard wail and yelp tones that are still featured on electronic sirens today.  But the one thing that really set the PA5 and PA10 apart from later Federal electronic sirens is that these models were designed to simulate the sound of a mechanical siren.  I’ve heard a PA5, and the ‘wail’ tone sounds much like a Q2b mechanical siren.   The PA5 and PA10 were in production from about 1960 to 1962, and either one in working condition would be a rare find.

PA5 sound sample: pa5

PA15 and PA20

The brown face / blue face era began with the PA15 and PA20 around 1962.  What sets these sirens apart from later versions of the Director and Interceptor is that both models have wail, yelp, and ‘alert’ tones.  The ‘alert’ tone is just a steady tone that plays at constant pitch – it doesn’t rise or fall.   Federal abandoned the simulated mechanical tone in favor of a more rounded synthesizer-like tone when the PA15 and PA20 were introduced. The sound of these sirens is much deeper and lower-pitched than what we are accustomed to hearing nowadays.  I’ve never heard a PA15 or PA20 in use on a ‘real life’ emergency vehicle, but I have heard the PA15/PA20 sounds on many TV shows and movies that were produced from the late 1960s right on up to the early 1980s.   For example, the siren sounds that were dubbed in for Squad 51 of Emergency and the patrol car on Adam-12 were a recording of a PA15 or PA20 running in ‘manual’ mode.  Or the dual siren tones of the police cars on Hawaii Five-O were overdubs of  PA15 / PA20 wails and yelps.  Over the course of production the PA15 and PA20 underwent several minor internal design changes, but the circuit board layout remained roughly the same until the end of production.  Letters at the end of the serial numbers indicated revisions to the circuitry, such a F1, E1, F1A, E1A, F1B, E1B, etc.  PA15 serial numbers began with ‘F’ and PA20 serial numbers began with ‘E’. Production of the PA15 and PA20 ended in 1966.

PA15 / PA20 sound sample: pa15pa20

Early PA15A and PA20A

The PA15 and PA20 were replaced by the PA15A and PA20A in 1967.  The PA15A has wail and yelp tones only while the PA20A has wail, yelp, and hi-lo tones.  The hi-lo tone is an electronic simulation of the hi-lo horn sirens that were used on European ambulances.  With the change in the control panel layout came a complete change in the design of the siren oscillator circuits. The early PA15A and PA20A models also had deep low-pitched tones, but the wail and yelp tones rose and fell a little differently than those of the PA15 and PA20.   The wail tone rose more slowly, and the yelp had a distinctive throaty ‘wah-yu wah-yu wah-yu’ sound, almost like a human voice.   PA15A serial numbers began with the number ’1′, while the PA20A serial numbers began with the number ’2′. The first number was followed by a letter – A, B, C, or D, and the letter indicated that there were changes to the circuitry.  I’ve never seen an A series unit, so I’m assuming that it was either a prototype or demonstrator that never made it to full scale production.  There are service manuals for the B, C, and D series however.  The early PA15A and PA20A sirens were in production from 1967 to about 1970, although there seems to be a lot more 1D and 2D series units around than the earlier versions.

Early PA15 / PA20A sound sample: early15a20a

PA15A series 1E and PA20A series 2E

The Director and Interceptor siren oscillator circuits would undergo one last major change in the early 1970s. These units have the letter ‘E’ in their serial numbers. The circuit boards in the E series units are completely different from the earlier PA15A and PA20A units. The new models, PA15A series 1E and PA20A series 2E, would have high-pitched wail and yelp tones much like the electronic sirens we hear nowadays. Sometimes I have to listen closely to tell the difference between a Federal PA15A 1E or PA20A 2E and a Carson/SVP SA450! One possible reason for going to the higher pitched sounds was that more compact speakers were coming into use, and smaller speakers reproduce higher frequency sounds better than low frequency sounds.  Federal’s TS100 speaker, the same speaker that is used in the TwinSonic light bar, is one such example.    I first heard the high-pitched E series PA15A/PA20A sounds around 1973, although someone told me that the circuit was introduced in 1970.   In any case, the PA15A series 1E and PA20A series 2E were in production throughout most of the 1970s and ended in the early 1980s. The 1E and 2E use 2N2925 transistors in the siren oscillator circuit, and the 2N2925 circuit was also used in the PA150, PA200, and PA1000 sirens. Besides the high-pitched wails and yelps, the other thing that makes the 2N2925 circuit unique is that goofy ‘in-between tones’ can be heard simply by turning the selector knob between wail and yelp or yelp and hi-lo.  The E series are by far the most common version of the Director and Interceptor, but remember that they are 1970s models and were in production when many ambulance companies were switching to van-based units.

PA15A 1E / PA20A 2E sound sample: highpitch

Chassis covers

In terms of outward appearance, the chassis cover is the most distinguishable feature when comparing the PA15 / PA20, early PA15A / PA20A, and PA15A 1E / PA20A 2E.  The PA15 and PA20 have a short chassis cover, the early PA15A and PA20A have a long chassis cover with small ‘grille’ at the back, and the PA15A 1E and PA20A 2E typically have rows of holes on the back half of the chassis cover for ventilation.  The latter two chassis covers are interchangeable, so a cover is not a reliable indicator of period correctness.  I have a PA20A 2D with a 2E chassis cover, and on the surface it does look like a 1970s PA20A.

Circuits

The circuit board is the most important part of the siren.  This is where the wails and yelps com from, and the sounds of the sirens changed along with the circuitry.  I have the three basic variations of the blue face Interceptor siren: a PA20, an early PA20A, and a PA20A series 2E.  The circuit boards of all three sirens are entirely different, and they sound different too! The PA20 circuit board is brown, the early PA20A circuit board is a cream colour with a set of wires running over top, and the PA20A 2E board has all wires running underneath.

Identification labels

The serial number is stamped into a metal plate on the bottom of the PA15 and PA20, while the PA15A and PA20A have a silver-grey label on the bottom.  There are at least nine different versions of the PA15 and PA20 and five different versions of the PA15A and PA20A.   So for example if you have a PA20A with the serial number E1C, then you need to get a PA20 series E1C owner’s manual with the component location and schematic diagrams.  Or if you have a PA15A series 1B, you need a PA15A 1B manual.  A 1E manual won’t help because the board layout and components of a 1E are entirely different compared to the 1B.

So, returning to that 1970 Superior 54” high-top ambulance restoration – which siren to install?  Either a PA15A series 1D or a PA20A series 2D.   A 1B or 1C or a 2B or 2C would also be period correct.  All of these variations have the deep low-pitched slow rising wail and yelp tones.   Even a PA15 or PA20 would work, although they are much older sirens.   And if you can’t find any of the above, a mechanical siren will do.

Leslie Ehrlich

Leslie Ehrlich is a self proclaimed  ‘armchair pro-car ambulance enthusiast and a siren fanatic’.  We would like to thank him for sharing his extensive knowledge of the history of electronic sirens and warning equipment.

Electronic Sirens – A discussion.

Electronic Sirens on Emergency Vehicles
ANOTHER “FAILED EXPERIMENT” FROM THE SIXTIES?
By
Kevin O’Connell

Are you still wearing corduroy bell bottoms? Nehru jackets? Beatle boots? Shag haircuts? Paisley shirts? Ben Franklin sunglasses?

Do you still refer to a raincoat and wading boots as turnouts? Do people still ride your tailboards with impunity?

Listening to “Boss Hits” on your 4 track? Driving a “really groovy” VW bus with tie-dyed curtains?

Hopefully your answers to these questions are all emphatically negative. Thankfully many of you are too young to remember the embarrassing things people did twenty five to thirty years ago (as if you could care – you’re too busy tattooing and piercing yourselves so you’ll have something to be embarrassed about in the future).

Why then, do many agencies still cling to another bad idea from the sixties; the electronic siren? After all, they seem to do a better job of instilling false confidence than actually warning other drivers. The answers and excuses I’ve heard over the years are numerous and nearly always rooted in myth or ignorance. In the interest of brevity, let’s just debunk the three most common notions:

Read more

Casket Lowering Device

Vintage Ambulance Equipment.

« Previous Page