1980-2000: Evolution of Artificial Respiration

So we must continue on our journey through the evolution of artificial resuscitation or respiration. This journey made it's way from simple mouth to mouth breathing all the way to volume ventilators. That pretty much takes us to the 1980's.

Figure 1 -- Drawing of Down's Flow Generator
Face Mask CPAP

1980s: Down's Flow Generator:
Continuous Positive Airway Pressure (CPAP) was something that was researched in the 1930's and 40's and then dropped. This research was picked up again as it was believed a continuous flow of pressure during inspiration and expiration might be helpful to patients with sleep apnea and chronic lung diseases.

The most common mode of delivery was by using a Down's Flow Generator. The generator was connected to a 50 PSI source and corrugated tubing. The opposite end of the tubing was connected to a mask with a Positive End Expiratory Pressure (PEEP) valve. (Keep in m;ind here that PEEP and CPAP are basically the same thing.)  The mask was securely strapped to the patient's face.

A pressure manometer was sometimes attached to the mask and an oxygen analyzer was sometimes added to the circuit using a T-piece to monitor how much oxygen the patient was receiving. A venturi-system allowed the caregiver to determine the percentage of oxygen allowed to the patient.

Ideally, a CPAP of 7.5 was supposed to increase the partial pressure of oxygen of alveolar air (PaO2) by one percent, just enough to force more oxygen into the blood to make a clinical difference. It is in this way that CPAP or PEEP were determined to improve oxygenation. (1)

A nice thing about these generators is they were completely pneumatic, meaning no electricity was needed. A downside to these generators is that they did not have alarms, meaning there was no way of knowing for sure that the patient was getting in the dialed in CPAP.

This system was used until the mid 1990s when electronic noninvasive positive pressure breathing machines entered the scene. We had one of these units at Memorial Medical Center when I started working, although I never had the good fortune of using one.

While rarely used in hospitals today, they are still used by Paramedics in the field.

1980s: Pressure Support Ventilation:

1980s: Pressure Controlled Ventilation:

1980s:  Airway Pressure Release Ventilation:  here is a good article.

1980s: Inverse Ratio Ventilation:

Puritan Bennete 7200

1983:  Puritan Bennett 7200 Micro-processor Ventilator:  This was the first microprocessor volume ventilator to hit the market. The machine was very durable and simple to use.  The settings were set by scrolling through an LED screen, and alarms were set in the same way.

It was easily used, portable, and worked well for the patient.  It quickly became the "most widely used ventilator around the world, capturing a 60 percent share of the international market by the end of the decade. (2)

This was the most common ventilator when I entered the respiratory therapy scene in 1995. It was in a majority of hospitals I worked as a student.

Bird 6400 ST

1986:   The Bird 6400 ST:   This ventilator was the first of the new generation of volume ventilators to hit the market. It was a rectangular shaped ventilator with all your basic knobs on the front, including volume control, assist control, SIMV, PS and CPAP modes. It also had a PEEP valve that was easily adjusted by a dial, and a full set of alarms.

The only knock on this simple device was the expiratory valves needed to be cleaned between each use and were a pain in the butt to put back together and keep in functioning order. It was a very compact ventilator for its time. We had two of these ventilators at Memorial Medical Center (MMC) when I started in November of 1997.

After purchasing a Servo 300 Ventilator around 2000, we kept one Bird in circulation until 2008.

1988: Respironics BiPAP:  It was introduced to provide noninvasive positive pressure ventilation to spontaneously breathing patients in the hospital setting using a mask. It could be set in ST mode to deliver IPAP and EPAP, or it could be set in CPAP mode to deliver CPAP.

Servo 300

1991: Seimen's Servo 300 Ventilator. This was a replacement ventilator for the Servo 900 and was generally created to complete with the the Puritan Bennett 7200.  It was much simpler to use than the old 900 version, and therefore was less intimidating. It included some very nice features, and some new modes, as noted below.

1991:  Pressure Regulated Volume Control: It had a new mode called Pressure Regulated Volume Control (PRVC) which made it so the patient could get a guaranteed volume, yet a sensor in the machine sensed changes in patient lung compliance to make sure the lowest pressure possible was given.

1991:  Volume Support:  Similar to pressure support, although it guaranteed the patient achieved a certain tidal volume with each breath. It was basically a pressure support breath that guaranteed tidal volumes. When weaning a patient.

1991: Automode: The Servo 300 had an option called automode. The caregiver would set the patient up in a control mode. As the patient began spontaneously breathing, the machine would sense this and switch over to a support mode. For instance, if PRVC was the set mode, the machine would switch to volume support (VS). If Pressure Control was the set mode, the machine would switch to pressure support (PS).

Servo 300 A Control Panel

This was nice because it allowed patients to control the ventilator rather than the other way around. This was another mode that made mechanical ventilation more comfortable for patients.

It could also be useful as a tool to see if patients were ready to be weaned. For instance, a post operative patient would be started in PRVC mode with automode. When the patient began to wake up and spontaneously breathe, the machine would sense this and switch over to volume support.

Of course, if the patient stopped spontaneously breathing, the machine would sense this and switch back to PRVC.

1991:  Flowby:  Another neat feature of this machine was that it allowed caregivers to choose between pressure sensitivity or flow sensitivity. Prior to the Servo 300, most ventilators used pressure sensitivity, meaning the patient had to make an effort to draw in a set pressure, usually 2-3cwp.

Flowby actually made machines more sensitive to the needs of the patient. A constant flow was maintained throughout the circuit. As the patient drew some of this flow, a breath was given.

Therapists had a choice between setting the sensitivity between 2-14 cwp, or in the green flowby range. As therapists became educated on the benefits of flowby it became the preferred choice. I believe most newer ventilator models do not even offer pressure sensitivity as a choice, and simply go with flowby.

1991:  Ventilator Graphics:  Another neat feature of this ventilator is that it also allowed for a graphics screen to be added. I think our machine did not have the graphics screen initially, but it was eventually added. This was nice because you could use graphics to adjust settings to improve patient comfort. Graphics also helped determine if suctioning was needed, or if there was a leak in the system. This was all part of improving patient comfort.

And that's not all.  It was also the first ventilator that could be adjusted for use by adults, pediatrics, and neonates. This made it a more universal device. Safety valves were in place, whereby neonates could not receive a tidal volume higher than 40, and pediatrics could not receive a tidal volume higher than 400.

Alarms were all red knobs. The LED showing dialed in settings were green. The LED showing what the patient was doing were all red. This made it easy to know what the machine was doing and what the patient was doing. We would often tell nurses, "Red bed, Green machine."   (d)

 This ventilator was used at MMC until the purchase of a Servo i made it no longer relevant. It continued to be a back-up ventilator until taken out of service in 2015.


1992:  V.I.P. Bird Infant Pediatric System

It was referred to as the T-Bird ventilator. At the time it was also the first and only ventilator that was mobile.

1988:  Noninvasive Positive Pressure Ventilation (NIPPV): Providing positive pressure breaths using a ventilator hooked up to an endotracheal tube was nice, although it was associated with a host of complications, and this was mainly due to the fact that it was invasive. Invasive ventilation essentially entails providing mechanical breaths through an endotracheal tube.

It was linked with an increased risk for nosocomial pneumonia. It was also difficult to get patients with end stage lung diseases weaned from ventilators. This created an ideal market for NIPPV.

NIPPV is essentially mechanical ventilation without the use of an endotracheal tube. It generally entails using applying a mask to the patient's face. In the hospital setting a full face mask is used, or a mask that covers the mouth and nose. However, a nasal mask or full

Now, technically speaking, IPPB was a form of NIPPV before NIPPV became a common acronym for CPAP and BiPAP machines. Electronic CPAP machines became common for the treatment of sleep apnea. A constant flow of pressure during inspiration and expiration helped to keep airways open. This assured the upper airway did not collapse while sleeping, and made sure that apnea episodes did not happen. It also kept alveoli open to assure adequate oxygenation.

Electronic CPAP machines were produced by a variety of manufacturers for use at home. These machines have become smaller, quieter, and more convenient over the years.

BiPAP is an acronym for Bilevel Positive Airway Pressure. It was first used in 1988 by professor Benzer of Innsbruck. It refers to a machine that delivers PEEP/ CPAP during expiration, and Pressure Support during inspiration.

When BiPAP is used, different acronyms are used as follows

• Inspiratory Positive Airway Pressure (IPAP): This refers to pressure support, or a flow of positive pressure during inspiration to assist with inspiration. This basically helps to control ventilation, or to assure adequate tidal volumes. This is adjusted to blow off carbon dioxide. However, increases in tidal volume may also improve oxygenation. 
• Expiratory Positive Airway Pressure (EPAP): This refers to a constant flow of pressure on expiration, also known as CPAP or PEEP. This keeps airways open. It increases the partial pressure of oxygen in the alveoli to force more oxygen into the blood stream. This is adjusted to improve oxygenation. 

Machines used in the hospital setting tended to be larger than home machines. This was due to the need for alarms in the hospital setting to monitor tidal volume, pressure, and oxygen levels. 

BiPAP machines became increasingly popular during the 1990s. Most were capable of providing patients with either CPAP or BiPAP, and this made it so that Downs Flow Generators were no longer needed and were phased out. This was about the phase I entered into. As a matter of fact, when I was in RT school BiPAP was covered vaguely. When I started as an RT it was only occasionally used. 

Early machines were were electric although not connected to oxygen. This meant that oxygen had to be bleed into the circuit from an external source. This sometimes made it difficult to meet oxygen demands of patients, and resulted in some patients being intubated. This problem was solved by later BiPAP models, such as the Vision. 

Regardless, early BiPAP macines gave physicians another option for helping patients. They were increasingly used for who were in respiratory failure or impending respiratory failure. This basically offered physicians a noninvasive method of treating hypoxia and ventilatory failure in patients who had a spontaneous drive to breathe, and who were capable of ripping the mask off if necessary. These machines prevented many patients from needing a ventilator, and they are still used to this day. 

1996: Respironics Vision:  

 Some of the initial models were crude and called for supplemental oxygen to be connected into the system, but new systems, such as the Vision, are touch screen, have flow and pressure waveforms, and allow the machines to be used pretty much like a ventilator.  The advantage is you can ventilate a patient and improve oxygenation without having to intubate the patient.  Masks can be removed for eating and drinking and taking medicine, and also oral care.  Studies show these machines work great for COPD, CHF and even some asthma patients.  They also work well for home use for patients with obstructive sleep apnea. Modern BiPAP machines are also more effective than the aforementioned down's flow generator in delivering CPAP, and the machines also allow for alarms and patient monitoring. 

2000:  Servo i, 840, Avea Ventilators

It has all the same features as the Sero 300 except that the flaws of the 300 have been corrected.  Instead of having all the dials on the front the settings are set by an easy to use touch screen.  The basic settings of rate, tital volume, and FiO2 could be set either this way or by quick access dials on the bottom of the screen.  The ventilator was also connected to a graphics screen for easy to see ventilator graphics.  (d)  Other similar ventilators include the Puritan-Bennett 840 and the Avea Ventilator.  These newer vents are microprocessor vents that include a variety of modes to improve patient comfort.  They also include waveforms to monitor the patient, and a variety of alarms.  Modern vents are also upgradeable. 

The future:  What will the future bring?  


References:

1. n l Need Reference
2. "Puritan Bennett Corporation History," fundinguniverse.com, http://www.fundinguniverse.com/company-histories/puritan-bennett-corporation-history/, accessed 4/8/16

References

1. (d)"About us:  History of Ventilation," maquet.com,  http://www.maquet.com/sectionPage.aspx?m1=112599762812&m2=112599885558&m3=112600545105&m4=112806653448&wsectionID=112806653448&languageID=4, accessed February 27, 2012
2. "Face Mask CPAP," 

1956: The A-B-Cs of CPR are born

In 1949,  Dr. James Elam, an anesthesiologist, investigated old records of how mouth to mouth breathing was used on newborn infants.  While trying to save the life of a boy, he used this method and it worked.  This was the beginning of the re-birth of mouth to mouth resuscitation.  (1)

I say re-birth because when the Royal Humane Society was established in 1773, mouth to mouth resuscitation was recommended as one of many options for reanimating victims of near drownings. It as later removed from the list due to complaints that it was gross and unhygienic. The Sylvester and Shaefer methods of reanimation were added in its place.

Dr. Elam and Dr. Peter Safar would prove that neither the Sylvester nor Shaefer method provided enough tidal volume, although mouth to mouth breathing did. So this brought back the method once thought to be gross and unhygienic.

Also recommended by the Humane Society back in 1773 were chest compressions and abdominal thrusts, and these were ultimately phased out.

By the 1890s chloroform was a common anaesthetic during operations. Occasionally a patient would go into what was then referred to as "chloroform syncopy." This was a term used to describe patient's who stopped breathing and ceased to have a heartbeat, or who were in cardiac arrest. Physicians had no treatment for this, and so it was almost always fatal. (3, page 6)

However, in his 1891 book, "General Surgery," Dr. Franz Koenig of Germany described using "external cardiac massage" to treat such a patient at the University of Goettingen. He recommended compression of the chest over the heart at a rate the person would spontaneously breathe. He later settled on a rate of 30-40 per minute, and recommended chest compressions during "chloroform sycopy" instead of one of the other methods of resuscitation.  (3, page 6) (4, page 2968)

A search was ongoing to determine the optimal rate to perform chest compressions. The first official recommendation was to perform 60 compressions per minute. (3, page 6) (4, page 2968)

A year later, a resident at the University of Goettingen, Dr. Fredrick Maass, and a student to Dr. Koenig, published a paper in the Berlin Clinical Weekly called "Resuscitation technique following cardiac death after inhalation of chloroform." Here he described the first successful use of external cardiac massage. He observed a clinical response from the patient at a compression rate of 120 per minute.  (3, page 6) (4, page 2968)

Ever since then the rate of chest compressions has been the subject of much debate and many studies. The recommendation as of March 28, 2010, by the American Heart Association is 100 per minute. The main reason for choosing this number is seems to be effective and easy to remember.

Studies during the 1940s showed that chest compressions stimulated blood to circulate through the body, and this was essential during artificial resuscitation.  This revolutionary idea transformed artificial respiration to cardiopulmonary resuscitation, otherwise known as CPR.

In 1956, while having a conversation with Dr. Elam, Dr. Peter Safar came up with the following anagram for artificial resuscitation: (1)

• A (Airway)
• B (Breathing)

Although the anagram was later changed to:

• A (Airway)
• B (Breathing)
• C (Circulation)

Thus was the beginning of the modern A-B-C's of artificial resuscitation, now more commonly referred to as cardiopulmonary resuscitation, or CPR). It was taught to all the citizens of the world who aspired, or were required by their employers, to save lives.

The American Heart Association officially endorsed CPR in 1963, and in 1966 adapted their first guidelines for performing CPR. These guidelines are reviewed every five years and updated.

A most significant change came on October 8, 2010. Here the decision was made to change A-B-C to C-A-B. The reason for the change was noted in the "2010 Guidelines for CPR and ECC: "

There are many reasons for this change. First, this change allows rescuers to begin chest compressions right away. As we know, most victims of sudden cardiac arrest (SCA) receive no bystander CPR. One of the reasons for this may be that the A-B-C CPR sequence began with opening the airway, the most difficult and daunting task for the rescuer. This change attempts to decrease the barriers to performing CPR by allowing the rescuer to start with chest compressions. Also, the vast majority of SCAs occur in adults who suffer a witnessed arrest and ventricular fibrillation or pulseless ventricular tachycardia. In these victims, critical elements of resuscitation are chest compressions and early defibrillation, which can begin earlier if there is no delay to open the airway and provide breaths. The process of opening the airway (which may involve getting a barrier device or setting up ventilation equipment) takes time and delays the start of CPR. Using the C-A-B sequence lessens this delay. 

For those not familiar with the terms "ventricular fibrillation" or "pulseless ventricular tachycardia," these are names for life threatening cardiac arrhythmias, or ineffective heart rhythms. This change included adults, children and infants, but not newborn infants. The ABC algorithm should be used for newborns, because "newborn cardiac arrest is most often respiratory."

The American Heart Association made one other change to increase the chances that CPR would be performed by bystanders: it removed the recommendation to perform mouth to mouth breathing. Once coming upon a witnessed or non-witnessed cardiac arrest, and once confirming that the person is non-responsive, the recommendation is now to perform effective chest compressions until emergency responders are on the scene. 

Modern studies also proved the following: 

• Mouth to mouth breathing provided enough positive pressure, coupled with the natural recoil of the chest after a compression, to allow for enough ventilation to occur. 
• That circulation was far more important than breathing (It may also be underestood that chest compressions causes pressure changes within the chest to allow for ventilation to occur, thus eliminating the need for mouth to mouth breathing.) 
• That bystanders were more likely to do CPR when all they had to do was chest compressions

That's all I'm going to write about CPR. 

References: 

1. Donahue, Mary, "History of Lifesaving," DeAnza Collegge, http://faculty.deanza.edu/donahuemary/Historyoflifesaving, accessed 8/10/13
2. "2010 AHA Guidelines for CPR & ECC," American Heart Association, 2010, http://cpr.heart.org/idc/groups/heart-public/@wcm/@ecc/documents/downloadable/ucm_317319.pdf, accessed March 28, 2010
3. Figl, Marcus,  et al., "Resuscitation Great: Franz Koenig and Friedrich Maass," Resuscitation, July, 2006, 70, pages 6-9
4. Nolan, Jerry P., et al, "Editorials: Chest Compression Rate: Where Is The Sweet Spot?" Circulation, 2012, 125, pages 2968-2970)

1920: The Lungmotor (a resuscitation device)

Lungmotor carrying case.

The Lungmotor was a simple device for assisting emergency crews during the 1910s and 1920s. It's intended use was for patients exposed to gases, electrocutions, or near drownings. 

As you can see by the pictures, it was basically a pump, like a bicycle pump, connected to the patient by tubing and a mask that fit over the patient's mouth and nose.

The Lungmotor with case and booklet.e

The company booklet, simply titled "The Lungmotor," basically recommended the device for near drownings.  The recommendation was for immediate removal of patient from the water. Manual methods should be used to remove mucus and water from the mouth and to provide breaths until the Lungmotor was on the scene.

 "The LUNGMOTER," the booklet says, "will remove the remaining water and mucus at the same time supplying a sufficient volume of air to resuscitate the victim." (1, page 8)

It's "a simple and easily understood device."  (1, page 14)

The LUNGMOTOR consists of two air pumps which operate in unison, yet are not connected in any way as far as the interchange of air is concerned. At no time does the devitalized air come in contact with the fresh air or oxygen.

The Lungmotor was supposedly "foolproof." Operating it was generally "easy," according to the booklet. To operate it all you had to do was: (1, pages 9, 11, 15)

1. Set the pin to the approximate size of the victim: (1, pages 9, 15)
• Newborn
• 5 Years
• 10 Years
• 15 Years (or small adult)
• Adult Average
• Adult Large
2. Place the mask on the patient  (1, page 11)
3. Pump (1, page 11)

The booklet, thus, notes various advantages of their product over competitor products: (1, page 13)

1. Easy to carry
2. Easy to understand
3. Easy to use
4. It's worked by hand
5. It can always give air (the kind you use every day)
6. Or you can add an oxygen tank to supply supplemental oxygen
7. Easy to increase and decrease volume (just move the pin)
8. It's safe and sure

A picture of the Lungmotor.
showing predicted tidal volumes
based on size of patient.
A pin was inserted
at the appropriate age
to prevent barotrauma.
 (1, page 9)

It also offers other physiological advantages to the patient: 

1.  It delivers the exact volume of air necessary to maintain the circulation and respiration over a long period of time. This is, as noted above, determined by setting the pin to the estimated size of the patient. (1, page 14)  Thus: 

The LUNGMOTOR does the very next thing to normal breathing because it supplies, mechanically, the tidal volume of air each respiration (the amount you breathe at rest), enough air, but not so much as to possibly injure the Lung tissues and the circulation, thus not leaving the patient liable to pneumonia following. (1, page 

2.  It always gives air to lungs, not stomach:  "This is accomplished by means of a tube which is introduced into the gullet and a bulb on the end blown up bv means of a hand bulb, and a soft rubber tube clamped by a clip. This tube is easily inserted because when pushed backward and down, guided by the under finger, it can go no place else but into the gullet." (1, page 14)

3.  It prevents you from providing too much pressure to patient "thus making it impossible to rupture the delicate tissue of the lungs."  This is due to the operator setting the pin to deliver the appropriate volume of air according to the size of the victim.  (1, page 14)

4.  It offers suction.  This causes expiration, and also allows for the device to "remove instantly and positively the large quantities of slime, mucus and blood that accumulate in the air passages, thus making it possible for the air to be delivered to the lungs which is not always possible (with manual resuscitation)." (1, page 14)

The fact that it offers suction is noted as one of the major advantages of the product, as noted by this passage: (1, page 13)

The fact that it reestablishes the suction action of the thorax on the heart and great vessels in addition to supplying the lungs with the correct amount of fresh air, is the explanation of the wonderful results obtained by the use of the LUNGMOTOR. The unsatisfactory results of past experiments in mechanical resuscitation were due to a failure to attach to this phase of the subject the importance which it deserved. (1, page 13, 18)

5.  It can provide oyxgen:  When not connected to an oxygen tank it supplied room air to the patient, which contains about 21% oxygen.  An oxygen cylinder could also be attached to the device in order to supply the patient with supplemental oxygen. (1, page 9)

6.  No risk of damaging a rib or liver, as often occurs with manual methods of resuscitation.  This risk is "entirely eliminated" with the Lungmotor, at least according to the booklet.

By this photo you can see the simplicity of the device.
It basically consisted of the cylinders, the handle,
and the mask.  (1, page 16)

So, how does it all work?  Again, according to the booklet:

The LUNGMOTOR consists of two cylinders which operate in unison, yet not connected in any way as far as the interchange of air is concerned. At no time does the divitalized air come in contact with the pure air and oxygen.

An upward movement of the handle charges the inspiration cylinder with pure air or any mixture of air and oxygen desired, according to the setting of the mixing valve (b). At the same time the expiration cylinder is filled with the expired air gently expelled from the lungs by the patient due to the natural contractual power of the chest walls and the elasticity of the lungs.

Conversely the following downward movement of the pump handle and piston places the air or the mixture of air and oxygen into the lungs and discharges the impure air through the outlet (o) into the atmosphere. In the case of drowning or new-born babies the water, blood, mucus, etc., is taken care of through the device and discharged at this opening (o).

Thus you see that at every complete stroke of the handle up and down you have a complete respiration, an inspiration, and an expiration—normal breathing mechanically done. (1, pages 14-15)

An early concern of manufacturers of mechanical resuscitators
was to make sure that expired air was kept separate from inspired air.
This was necessary to prevent patients from re-breathing
exhaled air, or exhaled carbon dioxide (CO2).  For this reason
the Lungmotor was designed with 2 separate cylinders,
one for inspiration (left) and one for exhalation.   (1, page 15)

The average breath given to an adult is estimated to be about 700 cc of air, which is "sufficient to maintain life, being, in fact, about 150 cc more than the patient normally breathes; this 150 cc. of air being used to counterbalance the natural resiliency of the lung in order to maintain the normal pressures in the thoracic cavity, and aid mechanically the restoration of the automatic mechanism of circulation by removing the obstruction in the lung, caused by the arteries crooking upon themselves when unconsciousness occurs. " (1, page 6-7)

The makers of the Lungmotor recommended the product be available for use by Rescue Teams, and that when someone was noted to be in a state of "suspended animation" that the rescue team be called for right away. However, in the meantime: "We believe manual methods if there are no other means of resuscitation available. But the use and the results from manual methods are limited." (1, page 6, 17)

Manual breaths, therefore, should be given, preferably by using Prone Method (Shaeffer Method), until the Lungmotor arrives on the scene.  

Criticism of the device was generally similar to any other mechanical resuscitator of the day, that it forced too much air too fast into the lungs, sucked too much air out of the lungs, and could only be used for a short period of time due to worker fatigue.

Note:  An advertisement for the Lungmotor can be found in "Modern Hospital," January, 1915, volume 36, number 1,  page 39

References: 

1. "Drowning: Historical-Statistical Methods of Resuscitation," no author nor editor listed, Published by Lungmotor Company, Boston, Massachusetts, 1920

1898: Matas's Apparatus for Artificial Respiration

Figure 4 (21)

Just prior to the turn of the 19th century arose the need for a means to prevent asphyxia when chloroform was used for surgeries. There was also the concern of preventing pneumothorax during artificial respiration.  (1, page 284)

It should be noted here that anytime positive pressure breaths are given to patients there is always the risk of applying too much pressure and blowing out a lung, thus causing a collapsed lung, more technically referred to as a pneumothorax. This is often referred to as barotrauma.

This was a major concern for the makers of ventilators all the way to the current century. Safety measures on modern ventilators work to prevent barotrauma. Yet back when these devices weren't so common, coming up with safety measures must have been a major concern. Much experimentation had to take place before any apparatus was put into use on any patient.

R. Matas devised the "experimental automatic respiratory apparatus" as you can see in figure 4.  This was never put in use on a real patient, and was mainly used to study the effects of pressure during inspiration and expiration.  (1, page 284)

You can see some of the major components in the picture: MF = O'Dwyer intubating cannula and stopcock for introducing chloroform; M = Mercurial manometer to measure pressure or vacuum; H is the handle to work the pump and forces air into the lungs.   (1, page 284)

The operator placed a finger over a hole in the O'Dwyer intubation cannula, and when he removed his finger expiration occured.  (R = Rubber tubing.)  It was quite a contraption for its time. Experiments were performed on dogs and human cadavers, although it was decided it was not fit for use on humans. (1, page 284)

References:

1. Tissler, Paul Louis Alexandre, "Pneumotherapy: Including Aerotherapy and inhalation...," 1903, Philadelphia, Blakiston's sons and Company, page 284,5

1830-1900: Early ventilators and intubation devices

Figure 1 -- Bouchut's Endotracheal Tube
(23, page 6)

If you are a physician, nurse, or respiratory therapist you can skip the next couple paragraphs. For the rest of my readers, I would like to take a moment to explain about breathing and artificial breathing. I want to explain about ventilators and intubation.

Obviously, in order to stay alive people must continue breathing. By 1830 physicians were well aware of this fact. This was important for victims of near drownings, and for patients who required anaesthetics during complicated surgeries. During these times, some method of artificial resuscitation was required, or some means of breathing for the these patients, at least until they regained their ability to spontaneously breathe.

How do people inhale? Natural inhalation occurs when the muscles of inspiration constrict, thus pulling the chest wall outward. This creates a negative pressure inside the chest resulting in air being drawn (sucked) into the lungs.

How do people exhale? Natural exhalation occurs when the muscles of inspiration relax, thus causing the chest wall to naturally recoil. This creates a positive pressure inside the chest resulting in air being forced out of the lungs.

Figure 5

Negative Pressure Ventilators mimic the natural means of inhaling. The patient is placed inside a tank that creates a negative pressure that draws the chest outward, thus causing inhalation. The problem with these machines is that they made it so that it was difficult to gain access to the patient. This problem was resolved with positive pressure ventilation.

Positive pressure ventilation essentially involves forcing inhalation by creating a positive pressure. The most primitive, and most basic, form of positive pressure ventilation is mouth to mouth breathing. Another mean is to provide positive pressure by using a mask. A modern name for this is noninvasive positive pressure ventilation, although this term would not be introduced to the medical profession for another 150 years.

By the 1830s, the medical profession was well aware of the importance of breathing. They had some methods of manual resuscitation, although most of these required more than one person to perform, were time consuming, and were exhausting. None could be performed for any length of time.

An added concern of these methods is that they involved moving the patient's arms and legs, risking injury to the body. They also did not guarantee that a patient was receiving an adequate tidal volume. So the need arose for some mechanical apparatus to provide artificial resuscitation.

That said, the need had arisen for a mechanical apparatus to provide, or at least assist, with artificial resuscitation. Ideally it would be something that would eliminate the risk of breaking arms and legs, would provide an adequate tidal volume with a low pressure, and would reduce or eliminate the need for manual power.

1832:  Dalzeil respirator:  In 1832, Scottish physician John Dalzeil described what many refer to as the precursor to negative pressure ventilators that would follow, including the Woillez Iron lung which is described below. (16)  It was essentially the first known example of noninvasive negative pressure ventilation.

It was a box, and he once used it to ventilate a man who was a near drowning victim.  The patient sat up while in the box with his head and arms outside the box.  The box was airtight, and bellows inside caused a negative pressure that caused inspiration.(16)

A window on the outside of the box allowed an observer to see if it was actually causing respirations.  This is often referred to as the first tank respirator, or the first iron lung.  The box had to have been hand powered, and there is no documentation it actually worked.  (16)

1845:  Oxygen breaths  Of course another thing that physicians learned early on was the importance of making sure a patient is getting enough oxygen while artificial breaths were being performed. A man named Erichson invented the first device that provided positive pressure breaths with oxygen through a cannula inserted through a pipe inserted into one of the nostrils.  He recommended ten breaths a minute.

Figure 4

1858:  Bouchut's Intubation Tube:  The noninvasive methods of providing positive pressure ventilation were not effective long term.  The negative pressure ventilators were fine, although they usually consisted of large, bulky tanks that made gaining access to the patient difficult. So another means was needed to provide artificial resuscitation long term. 

So this inspired early experiments with inserting hollow tubes into the airway.  This is considered to be invasive. So, from here on out, anytime a person needs to have a tube inserted into their airway to provide resuscitation, it is referred to as invasive ventilation. 

Earlier physicians tried using a catheter, but this wasn't very effective. In 1858, French physician Eugene Bouchut (1841-1898) became the first to describe insertion of a tube into the airway as opposed to a catheter in a case of dyspnea. The tube he used during seven cases between 1856-1858 (24, page 661-662) was a rounded silver tube narrower at the end to be inserted as you can see in Figure 1, and it was 1.5 to 2 cm long and 7 cm in diameter.

Interestingly, a silk thread was attached to the distal end of the tube that was "brought out to the mouth, and was intended to prevent the tube from going down the trachea or esophagus; and to allow it to be taken out when necessary." 

He later "insisted on the distinction between his method and catheterism." However, of the seven cases he cited to the French Academy of Medicine, only two lived and both required tracheotomy.  Yet he proved the procedure could be done. 

Various other physicians described success with this or similar procedures between 1858 and 1880 when Joseph O'Dwyer (see below) introduced a more effective tube. (see figure 1)(23, page 5)

1867:  Richardson's Double Acting Rubber Bellows:  Benjamin Ward Richardson created a bellow system similar to Hunter's Bellows (although he may not have known of Hunter's Bellows). The original system took up a lot of room, so he invented the double acting bellows, which "consists of two rubber bulbs terminating in common tube that was called the nostril-tube."  One bellow supplied inspiration, the other expiration.  (See figure 4)

1875:  Blake cures poison victim:  Using a device similar to Richardson's Bellows, Blake connected a reservoir of condensed oxygen to it and treated a case of acute poisoning with success.  Before this time artificial respiration (often referred to as insufflation) was used mainly to treat neonatal asphyxia, but now the focus was also on treating adults.  The nozzle of the device was inserted into the nostril.  

1876:  Woillez Iron Lung (Spirophone): While the iron lung wasn't mass produced until the late 1920s, there were some earlier models that acted as prototypes of later designs.  In fact, the design described by Woilliz was quite similar to the Drinker and Shaw and Emerson iron lungs.  The only drawback to Woillez's design was he didn't have access to electricity, so his machine was powered by hand.

At the French Academy of Medicine in Paris in 1876 Woillez described his respirator this way:

"(The apparatus is) a zinc or sheet iron cylinder large enough to receive the body of an adult up to the neck. It is equipped with wheels which permit moving it rapidly to the place where it is necessary. The cylinder set almost horizontal slightly inclined is hermetically closed at the boot end and open at the head end. Through this opening at the head end you slide the body of the patient by means of a sort of stretcher equipped with rollers, on which he is previously placed; then you close the head opening around his neck by means of a diaphragm that you attach to the edges of the opening. The head thus remaining free rests on an appropriate support. A flexible impermeable fabric attached to the cover diaphragm is secured around the neck to avoid as far as possible the passage of exterior air to the inside of the apparatus, at the moment when the vacuum is produced there.

The air thus confined in the apparatus around the body of the patient can be partially rapidly withdrawn by means of a powerful aspirator bellows of about 20 litres capacity actuated by means of a lever. The interior of this pump communicates with the interior of the apparatus through a large tube tightly screwed on." (17)

There were other similar designs, yet none became mass producible mainly due to lack of knowledge of electricity at the time.

O'Dwyer's Intubation Tube for a child 2-3 years old (23)

1880:  The first useful endotracheal tube:  Dr. Joseph O'Dwyer (1841-1898) of New York, and his fellow physicians at the New York Foundling Asylum, observed problems with trachetomy.  He decided another means of breathing for patients was necessary, and he at first trialed flexible catheters into the nasal passages.

Yet this didn't meet his satisfaction so he devised a tube to be placed into the larynx where it would remain.  By trial and error he tinkered with the device until it met his satisfaction.  The device was made with a bivalve tube with a narrow transverse diameter, and about an inch long."

A shoulder on the upper end prevented the tube from slipping down.  By trial and error the tube transformed so the tube was a "plain tube of elliptical form about an inch in length."  He then played with longer tubes until he found the desired length.  The final tube used was made of brass and lined with gold, and was accepted by the medical community.  (See figures 2 and 3.)

A complete set was included in a box, that included sizes for different aged children, an obturator, an introducer, an extractor, and a gag.  The length of the tubes in inches were 1.5, 1 3/4, 2, 2.25 and 2.5.   The obturator of the physicians choice is connected to the end of the introducer, and this is used to insert the tube.  If necessary a small thread could be inserted and tied to a hole on the outer edge of the tube to prevent it from going down the trachea, and to facilitate removal.

The kit also came with a scale (see figure  5) which helped the physician determine appropriate depth of the tube according to age.  The scale is used like this: "The smallest tube reaches line 1, and is intended for children about one year and under. The next reaches line 2, and is for children between one and two years. The third size, marked 34 on the scale, should be used between two and four years. The fourth, marked 5-7, is for the next three years, and the largest tube is for children from eight to twelve."

O'Dwyer also designed larger tubes and equipment for adult intubation. (23, page 9-18)

O'Dwyer's introducer connected to obturator (23, page 16)

1888:  Foot operated Bellows

Dr. George Fell invented a system of bellows whereby the operator would use his hands to provide positive pressure breaths.  He would either use a tracheotomy or face mask.  In 1891 this system was revised by Joseph O'Dwyer of New York so that breaths were provided by pressing down on a lever with your foot.  O'Dwyer preferred to connect his bellow system to an endotracheal tube.  O'Dwyer was concerned about over-distention of the lungs due not allowing enough time for expiration, and therefore recommended giving slow breaths, or 10-12 per minute. (21, page 283)

1891:  Concerns of Intubation:  By the late 19th century many of the same concerns physicians have today about intubation were considered.  One such concern being the ulceration of tissue due to pressure of the tube set upon it for a long period of time.  Tubes were generally taken out after six days with success, although in some cases were left in 12 days or longer. Dr. Rank, a German physician, ultimately recommended removal of the tube after 10 days, and if necessary, the physician should consider tracheotomy.

Some physicians recommended extubation after the 5th day, which would be in line with modern protocols. Feeding the patient was also a concern, and was either done with soft foods or liquids, or by nasalgastric tube.  It was recommended that if the tube was accidentally spit up that the nurse take advantage of the moment to try feeding the patient prior to re-introducing the tube (if the tube was still needed). (23, page 29-20)

1898 Matas's Apparatus for Artificial Respiration:  Around this time the need arose for a means to prevent asphyxia when chloroform was used. There was also the concern of preventing pneumothorax during artificial respiration.  Matas deviced the "experimental automatic respiratory apparatus" as you can see in figure 4.  

This was never put in use on a real patient, and was mainly used to study the effects of pressure during inspiration and expiration.  You can see some of the major components in the picture: MF = O'Dwyer intubating cannula and stopcock for introducing chloroform; M = Mercurial manometer to measure pressure or vacuum; H is the handle to work the pump and forces air into the lungs. The operator placed a finger over a hole in the O'Dwyer intubation cannula, and when he removed his finger expiration occured.  (R = Rubber tubing.)

It was quite a contraption for its time. Experiments were performed on dogs and human cadavers, although it was decided it was not fit for use on humans. (See figure 4) (21, page 284)

Figure 4 (21)

1900:  Cuffed Endotracheal Tubes and laryngoscopes

Right around the turn of the century was when the furst cuffed endotracheal tubes (ETT) started showing up.  This was necessary to prevent air from leaking around the tube so that bigger breaths could be given, and it also worked nice to prevent aspiration around the tube. 

Another problem was how to insert the tube into the ETT into the airway. Blind insertion meant there was a risk of intubating the esophagus, which, if not recognized, resulted in asphyxia and death. 

A laryngoscope is a device that allowed the doctor to open the airway in order to see the vocal cords and glottis. This increased the likelihood of tracheal intubation. 

A larygoscope was first described in 1855 using sunlight to see the vocal cords, and by 1913 a battery powered laryngoscope with an external light was invented.  This was refined so it had a handle with a battery and a light bulb at the end of the scope for easy visualization of the vocal cords.   (18)

Related posts:

• 4000 B.C. - 1800:  Evolution of Artificial Respiration
• 1800-1900:  The Beginning of Pressure Therapy
• 1800-1900:  The Beginning of Pressure Therapy (part II)

References:

1. Szmuk, Peter, eet al, "A brief history of tracheostomy and tracheal intubation, from the Bronze Age to the Space Age," Intensive Care Medicine, 2008, 34, pages 222-228
2. Price, J.L., "The Evolution of Breathing Machines," (this must have been written in the 1950s or early 1960s because the last reference was to IPPB being used as a respirator) (reference to The Bible, Kings, 4: 34)
3. Tan, S.Y, et al, "Medicine in Stamps:  Paracelsus (1493-1541): The man who dared," Singapore Medical Journal,  2003, vol. 44 (1), pages 5-7
4. "Resuscitation and Artificial Respiration," freewebs.com, Scientific Anti-Vivisectionism,  http://www.freewebs.com/scientific_anti_vivisectionism4/resuscitation.htm, accessed March 1, 2012
5. Price, op cit
6. Lee, W.L., A.S. Stutsky, "Ventilator-induced lung injury and recommendations for mechanical ventilation of patients with ARDS," Semin. Respit. Critical Care Medicine, 2001, June, 22, 3, pages 269-280
7. Price, J.L., "The Evolution of Breathing Machines,"  (see also reference #1 and #3 above)
8. Szmuk, op cit, page 225
9. Price, op cit
10. "Resuscitation and Artificial Respiration," freewebs.com, Scientific Anti-Vivisectionism,  http://www.freewebs.com/scientific_anti_vivisectionism4/resuscitation.htm, accessed March 1, 2012 (see also reference 1 above)
11. Lee, op cit
12. Price, op cit
13. Price, op cit
14. Szmuk, op cit, page 225
15. Price, op cit
16. Woollam, C.H.M., "The development of apparatus for intermittent positive pressure respiration," Anaesthesia, 1976, volume 31, pages 537-147
17. Previtera, Joseph, "Negative Pressure Ventilation: Operating Procedure (Iron Lung)," Tufts Medical Center, Respirator Care Programs, http://160.109.101.132/respcare/npv.htm, and http://160.109.101.132/respcare/ironlung.htm, accessed February 27, 2012
18. Szmuk, op cit, page 226-7
19. Fourgeaud, V.J, "Medicine Among the Arabs," (Historical Sketches), Pacific medical and surgical journal, Vol. VII, ed. V.J. Fourgeaud and J.F. Morse, 1864, San Fransisco, Thompson & Company,  pages 193-203  (referenced to page 198-9)
20. "Biographical Dictionary of the society for the diffusion of useful knowledge," Longman, Brown, Green and Longmans, volume III, 1843, A. Spottingwood, London, page 124-5
21. Tissler, Paul Louis Alexandre, "Pneumotherapy: Including Aerotherapy and inhalation...," 1903, Philadelphia, Blakiston's sons and Company, page 284,5
22. Hasan, Ashfaq, "Understanding Mechanical Ventilation: A practical Handbook," 2010, New York, Springer
23. Ball, James B, "Intubation of the Larynx," 1891, London, H.K. Lewis
24. Garrison, Fielding Hudson, "An introduction to the history of medicine," 1922, 3rd edition, Philadelphia and London, W.B. Saunders Company
25. Banser, Robert C., Sairam Parthasarathy, editors, Nocturnal Noninvasive Ventilation, Theory, Evidence, and Clinical Practice," 2015, Springer, New York, chapter 2, "Negative Pressure Noninvasive Ventilation (NPNIV): History, Rational, and Application," by Norma M.T. Braun

1800: Albrecht von Haller studies respiration

Albrecht von Haller (1708-1777)

Albrecht von Haller was not an asthmatic, although he was a sickly in his youth, and this would force him to focus on his studies.  He would become among the most brilliant minds of his era, and what he accomplished had a great impact on the evolution of many diseases, including asthma.

He was born in Bern, Switzerland, in 1708.  His biographer, Charles Bert Reed, said:

"Like many other men of genius, his infancy was sickly and feeble. He had rickets, which retarded his physical, even as it accentuated his mental, development. Driven in upon himself for entertainment, he studied, read, and drew designs at the precocious age of four." (6, page 17)

It was observed from a very young age that he was a genius. Reed said:

As with Mozart, Macaulay, Goethe, Leibnitz, and others, the most extraordinary things are told of Haller's ability and greed for knowledge. During his childhood he outstripped all his companions. By the end of his ninth year he was thoroughly familiar with the Greek Testament. He made a lexicon of the Greek and Hebrew words in the Old and New Testaments, with their different roots and meanings. He made a grammar of Chaldee. He assembled the lives of 2000 celebrated people, on the model of Bayle and Moreri, whom he had read. Unlike most boys he preferred long and exhaustive treatises with interminable sentences and no paragraphs. His unusual industry, his fiery zeal to educate himself, and his unlimited patience seemed to make nothing impossible. He, also, "took all knowledge for his province.'' (6, page 17-18)

He early began to exhibit the exceptional understanding, the unfailing memory, the tireless industry and the impulses thereto, that characterized his entire life. He entered upon his emotional period at the age of twelve. At this time, while sick with smallpox, he was inspired with love toward the young lady who read aloud to him, and to her he dedicated his first poem. It was written in French, and appropriately named "The Resolution to Love." (6, page 18)

After the death of his father, Haller moved nearer the city and entered the gymnasium. His thesis for admission was in Greek, although Latin was sufficient. He wrote much and after the manner of all aspirants to eminence he aped sedulously the form of some admired exemplar. Homer, Horace, Ovid, and Virgil were his familiars. Homer for romance and Virgil as the model for his verses. Being chained to his room often and long by reason of his feeble constitution, he took refuge in poetry, which he read and practiced in all the tongues he knew. He wrote poems of occasion, tragedies, translations of Ovid, Horace, and two books of Virgil, together with an epic of 4000 lines on the'' Origin of the Swiss Union of States." (6, page 18)

His father had wanted him to go into the ministry. However, when he was fourteen, and after his father died, he moved in with a friend of the family at Biel who happened to be a physician. This man had an impression on a young Haler, and inspired him to go into the medical profession. (6, page e18)

After a year at Biel, he went to Bern to start his medical education, then to Tubingen, and then to Holland where he studied at Leyden.  There he became a student of Herman Boerhaave, the leading medical professor of the era.  It was probably from Boerhaave that Haller would have learned as much about the respiratory tract and respiratory medicine as was available at that time. (6, page 18-19) (2, page 143)

Medical historian Thomas Bradford said he had such a zeal for anatomy that, while at Tubingen, he dissected dogs, and, at Leyden, he purchased half a body for dissection.  He also "engaged in grave robbing, and betrayed by the stench that arose, was obliged to flee." (2, page 143)

When he was 19 he showed senior Professor Coschwitz, who had dissected a new salivary duct.  Haller proved that it wasn't a salivary duct, it was a vein.  (1, page 322)(6, page 20)

In 1727, when he was only 19, he earned his medical degree.

So his gift of intelligence was evident at a very early age; he was a prodigy.  He would go on to become the greatest systematist (of medicine) since Galen, and one of the most imposing figures in all medical history," said Garrison.  He was "the master physiologist of his time." (1, pages 321-322)

He then traveled as part of his studies, and wrote poetry about nature along the way.  One of his poems, Die Alpen, was about his journey through the Swiss Alps in 1728, and it was finished in 1729, the same year he started his medical practice in Bern. The poem, along with several other poems he wrote, was published in his Gedichte in 1732. Die Alpen would end up being his most famous poem. (5)(6, page 21-23)

His book of poetry went through several editions, and, although some say it was quite popular, others contend that he wasn't the best poet.

In 1731 he gave lectures and demonstration at Basel, in place of his teacher. He then returned to Bern, "where his thorough knowledge, broad scholarship, and influential connections assured to him an immediate success," said Reed.  (6, page 27)

He added:

His practice increased, but he kept up his botanical enthusiasm. Ten miles a day he averaged over hill and valley in search of specimens, which he identified and wrote up in the evenings or during meals. Meanwhile his vast and various powers were fed with the most extensive, the most accurate, and the most elaborate study of botany, anatomy, and medicine. Not a moment was wasted. He reread the Greek and Latin writers wherever he happened to be—at the table, on promenade, and on horseback, and the major portion of his wedding day was spent upon an abstruse problem in Differential Calculus. (6, page 27)

He tried to get in as directing doctor at the University at Bern, and later as professor of history (he probably knew more history than anyone in Bern at the time), but he failed in attempts.    (6, pages 30-31)

At 26 he became professor of anatomy and director of the hospital at Bern. He became especially famous for his botanical and anatomical research, of which he earned the attention of King George II.  (2, page 143)(5)

King George II created Goettingin "in the hope it would surpass the universities of Halle, Leipzig, Wittenberg, and Helmstedt."  In 1736 King George II called Haller to the chair of professor of anatomy, surgery, chemistry and botany at this new university.  (2, page 143)(6, page 32-33)

His wife and his four children moved with him from Bern to his new home, and four weeks later his wife died.  The emotional stress of this even caused him to write another poem.

"Thy death, beloved, shall I sing? Ah, Mariane, what a theme! When sighs my words are mastering, And thought is but a troubled stream, That longing which for thee I feel, My constant needs intensify; The wounds within refuse to heal — Again I seem to see thee die. "My love too eager was, I know; But thou deservedst it and well; Thy form is mirrored in me so That all thy beauty I must tell. Each telling of this love for thee Some former joy recalls to mind; In part thou livest still in me, A tender pledge Love left behind."

In the meantime, Haller wrote many books, and some say he was so busy that he slept in a library, said Bradford. (2, page 143)

Bradford said he is often given credit as the physician to revive experimental physiology, or the study of the functions of living organism. This, according to Garrison, was a subject that was lacking since the great Galen studied medicine in the first century. (2, page 143)(1, page 322)

Garrison said Haller believed "the specific imminent property of all muscular tissue, and that sensibility is an exclusive property of nervous tissue or of tissues supplied with nerve. This classic research, based on 567 experiments, of which he himself performed 190, was made at Gottingen in 1757.  (1, page 323-324)

He believed that "the normal act of expiration hindered the flow of blood through the lungs," and "demonstrated that the lungs contracted when concentrated acid was applied to it."  (3, page 27)

He also performed experiments that would verify the spasmotic theoery of asthma, or at least that the muscular fibres that wrap around the air passages may spasm under certain circumstances. (4, page 4)

Haller was an avid athlete as a youth, and was burdened by sports injuries the rest of his life.  He was inflicted with a disease the Germans called Heimweh at the age of 45 in 1753, and retired to Bern for the remainder of his days, "leading a life of most varied activity as pubic health officer and savant, with a touch of 'Lord High Everything Else'." (1, page 323)

In the short time he spent as a physician, botanist, physioloist and anatomist, he earned the respect of his peers.  While most people simply forgot the man by the time the 20th century rolled around, his biographer Charles Bert Reed said that in his own time he was simply "surnamed the great." (6, page 14)

References: see "1870-1900: What asthma theory won the era?"

1. Garrison, Fielding Hudson, "An introduction to the history of medicine," 
2. Thorowgood, John C., "Asthma and Chronic Bronchitis: A New Edition of Notes on Asthma and Bronchial Asthma," 1894, London, Bailliere, Tyndall, & Cox
3. Brown, Orville Harry, "Asthma, presenting an exposition of nonpassive expiration theory," 1917, St. Louis, C.V. Mosby Company
4. Shmiegelow, Ernst, "Asthma, considered specially in relation to nasal disease," 1890, London, H.K. Lewis
5. "Albrecht von Haller," http://www.nndb.com/people/677/000096389/, accessed 1/10/14
6. Reed, Charles, Bert, "Albrecht von Haller: A Physician -- Not Without Honor," 1915, Chicago, Chicago Literary Club

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