One tidal volume of 180 milliliters will occur when the chin is pulled up.
Chin up.
Here.
Notice the chest motion which indicates a patent airway when positive pressure is applied from above.
Now we will study the currently taught back pressure arm lift method, also called Holger Nielsen method.
The subject is turned into the prone position.
The face mask which we are using is a special flat mask.
A conventional anesthesia mask would protrude and interfere with the natural position of the head when the subject is lying prone.
Now the rescue is performing the back pressure arm lift method as it was taught since 1951.
Namely, the subject's head is turned to the side and his hands are placed under his cheek.
An artificial oropharyngeal airway is in place which prevents obstruction by the lips and teeth and holds the tongue forward.
The spirometer shows that all tidal volumes are smaller than 50 milliliters.
This means no air reaches the alveoli.
Notice how each arm lift maneuver pulls the subject's body towards his head, thus increasing the flexion and torsion of the neck.
This is an enlarged copy of the spirometer tracing which you have just seen.
All tracings you will see are read from the right to the left.
Note that there is almost zero exchange and air is squeezed out of the lungs.
Now we will extend the neck so that the chin rests over the hands.
Again the spirometer shows no air exchange.
In some volunteers this extension of the neck improved the initial tidal exchange significantly.
However, the head moved back spontaneously into the flexed and twisted position as you see here and caused progressive obstruction.
A second rescue attempting to hold the head and jaw interfered thereby with the performance of the main rescuer.
The subject will be turned on his back for hyperoxygenation.
Hyperoxygenation can best be performed in the supine position.
In the prone position the face is fully accessible which makes jaw support and mask fit almost impossible.
Here the trachea is intubated and the subject is again ready for the performance of the back pressure arm lift method.
This time with an endotracheal tube in place which bypasses the pharyngeal area thus eliminating airway obstruction.
Observe the movements of the ink writer.
They indicate throughout tidal volumes of 400 to 500 milliliters.
The main factor limiting air movements now is not airway obstruction but the distensibility of the subjects lungs and chest also called lung chest compliance.
In this volunteer the compliance was measured to be approximately 50 milliliters per centimeter of water pressure for 1000 milliliters inflation.
Lung chest compliance is reduced in obese subjects and in subjects with pulmonary disease.
In the six subjects we have studied with the back pressure arm lift method and an endotracheal tube in place we obtain tidal volumes between 260 and 840 milliliters.
The low values in heavy subjects the high values in lean subjects.
You have seen that the principal cause of the failure of the back pressure arm lift method is airway obstruction due to malpositioning of the head and mandible.
We observed three types of obstruction.
First complete obstruction.
Second inspiratory obstruction only which is caused by a valve -like behavior of the pharynx.
The back pressure squeezes air out of the lungs succeeding arm lift maneuvers need inspiratory obstruction.
And third progressive obstruction.
Here the airway was open in the beginning and succeeding arm lift maneuvers caused flexion of the neck and zero exchange.
Now I will summarize all tidal volumes measured during performance of the back pressure arm lift method in all 15 subjects studied.
When it was performed as taught since 1951 the average tidal volume was 126 milliliters ranging from 0 to 780 milliliters.
Insertion of an artificial or a pharyngeal airway produced only insignificant improvement.
An average of 177 milliliters.
When the subject's head was placed in extension at the beginning the average tidal volume was 520 milliliters ranging from 0 to 1160.
Within a nutritional tube the average tidal volume was 566 milliliters.
May I point out here however that all these volumes must be considered borderline volumes.
A method which moves only 500 milliliters under ideal experimental conditions will often not be able to overcome in actual asphyxia victims airway obstruction due to mucus, vomitus, blood or other foreign matter.
Intermittent positive pressure breathing such as mouth -to -mouth breathing moved in all our subjects tidal volumes between 1 ,000 and 3 ,000 milliliters.
Before studying mouth -to -mouth breathing we calibrate the pneumograph with lung inflations of 500, 1 ,000 and 2 ,000 milliliters.
Here 1 ,000 milliliters of air are drawn through a gas meter into a bellows and pushed into the lungs through a tight fitting face mask and an artificial airway.
The deflection of the recording the right upper corner indicates 1 ,000 milliliters.
Now inflation with 2 ,000 milliliters.
We made three inflations with each volume.
The red arrow is mounted on the recording arm to make it visible on the screen.
In the other experiments we obtained a recording such as this one during mouth -to -mouth breathing.
Whenever the recorder of the pneumograph will not return to zero during expiration it is due to air blown into the stomach.
When this occurs it is advisable to recalibrate.
We were able in actual resuscitations to remove mucus, foam, vomitus or blood from the pharynx by forcing the victim's mouth open turning the head to the side and wiping mouth and pharynx clean with the fingers or a piece of cloth.
Now you We call it the thumb jaw lift method.
Note the hand positions.
The right hand pinches the nostrils.
The thumb of the left hand is inserted between the teeth.
The mandible is grasped at the midline with the left hand and pulled forcefully upward.
The pneumograph shows tidal volumes of 2 ,000 milliliters and more.
Technical details are of extreme importance.
Dropping the mandible as you see here obstructs pharynx and prevents inflation.
No exchange.
Chin up.
Correct technique.
Good exchange.
This is another mistake.
The rescuer forgot to pinch the nostrils.
Now you will see a finicky mouth -to -mouth contact.
A mistake often made by female rescuers.
Here.
The rescuer must open his mouth widely to cover the entire mouth of the victim plus the rescuer's own thumb to produce an airtight seal.
Now comes the alternate method or two hands jaw lift method.
Both hands grasp the angles of the mandible and pull forcefully upward.
The thumbs retract the lower lip to prevent obstruction by the lips.
Air leakage through the nostrils is prevented by the rescuer's right cheek.
This method we recommend for using victims in whom the thumb cannot be inserted because the mouth is tightly closed.
It also is a method of choice for infants in whose small mouths the rescuer's thumb would occupy too much space.
In infants, the rescuer's mouth covers the mouth and nose of the victim.
Here again the same mistake.
Chin down, pull exchange, chin up.
Good exchange.
Lip obstruction, as you see here, can also lead to failure of the method.
No lip retraction, no exchange.
Watch the thumbs.
Lip retraction, good exchange.
Mouth to nose breathing often produced much smaller tidal volumes than mouth to mouth breathing because of greater airway resistance.
Mouth to nose breathing sometimes met complete obstruction due to nasal congestion and mucus particularly towards the end of the mouth to nose breathing also proved to be less acceptable than mouth to mouth breathing.
The following mouth to mouth methods proved ineffective in the hands of lay rescuers.
This is the first poor method.
The right hand closes the nostrils, the left hand supports the right angle of the mandible.
Lay rescuers were unable to support adequately the mandible with one hand only at the angle of the mandible.
Also there is obstruction by the lips and teeth.
The second poor method.
Both thumbs pinch the nostrils, the other fingers hold both angles of the mandible.
Obstruction by the lips is not prevented.
Here reoxygenation by the correct mouth to mouth method.
The third poor method.
The right hand pinches the nose and the left hand supports the angle of the jaw.
Again inadequate jaw support and lip obstruction caused failure.
When laymen placed one hand over the stomach to prevent gastric distension the jaw was poorly supported and the failed.
The fourth method which proved insatisfactory.
For aesthetic reasons the rescue interposed his thumb and index finger in form of a ring between the victim's mouth and his own mouth.
Air leakage and obstruction by the lips caused failure.
No exchange.
Last poor method.
The rescuer tried to keep the victim's mouth open by pressing from the outside against his cheeks.
It proved difficult to locate the area on which pressure could be successfully applied.
This S -shaped breathing tube, also called mouth -to -mouth airway, made mouth -to -mouth breathing more aesthetic and more effective.
The large airway for use in adults and children.
The small airway for use in children and infants.
The end which remains outside is the mouthpiece for the rescuer.
First the airway is inserted.
One hand forces the mouth open, the other hand inserts the airway over the tongue taking care not to push the tongue back into the The rescue prevents air leakage through the nose and the corners of the mouth.
Either this way, or this way, or this way.
We demonstrate once more insertion of the airway.
The tongue may be held forward during insertion by one finger.
Correct position of the hands, deep inflations.
In spite of the use of the artificial oropharyngeal airway, the head must be held in extension at all times.
The flange must be pressed over the lips, the nostrils must be occluded, and the head must be held in extension.
Forceful blowing is necessary for resuscitation of adults, gentle inflation in children.
Here again chin down, no exchange.
Chin up, good exchange.
Here the airway is not inserted deep enough, full chest motion.
Correct insertion, good chest motion.
This is mouth to mask breathing.
First a conventional oropharyngeal airway is inserted in the same way the mouth to mouth airway was inserted.
The mask is held firmly over the victim's face.
An airway under the mask is essential to prevent obstruction by the lips.
Again the head must be held in extension.
Now we permit the subject to recover temporarily by discontinuing the succinylcholine infusion.
He now breathes spontaneously but very shallowly.
Mouth to mouth assisted breathing.
Limb movements return.
Shallow spontaneous breaths.
The assisted inflations must coincide with the subject's spontaneous inspiratory efforts.
Here assisted breathing is performed by the mouth to airway method.
The mouth to mouth airway was also used to provide airway patency in unconscious persons who were breathing spontaneously.
The airway should be left in place until the victim is sufficiently recovered to expel the airway or to react by retching or coughing.
The subject will be rendered again apneic by succinylcholine.
We studied the performance of portable resuscitation equipment in the hands of untrained rescuers.
They performed on paralyzed volunteers.
We used a bag mask unit with a source of oxygen, a bellows and a mechanical resuscitator.
During the first 60 seconds, less ventilation than with mouth to mouth breathing or no ventilation was produced with some of this equipment.
This was due to difficulty in maintaining a patent airway and a tight mask fit and due to a delay in getting the equipment set up.
Mouth to mouth breathing therefore should be started immediately when the victim is found while waiting for equipment.
Oxygen resuscitation equipment should be used when it arrives.
If the rescuer knows how to use it and knows how to maintain a patent airway and a tight mask fit, this boy scout will perform mouth to airway breathing.
He weighs 100 pounds.
He has some difficulty but corrects himself.
He was able to adequately ventilate subjects weighing up to 210 pounds.
This is a firefighter performing mouth to airway breathing.
87 untrained rescuers performed mouth to airway breathing.
All produced breaths larger than 500 milliliters within 60 seconds after one demonstration.
All could insert the airway within 40 seconds.
Although 50 percent of them had never inserted an artificial airway before.
The 167 untrained rescuers who performed mouth to mouth breathing on paralyzed volunteers consisted of firefighters, policemen, military personnel, Red Cross workers, medical students, doctors, nurses, housewives, and boy scouts.
This medical student also performed mouth to mouth and mouth to airway breathing after one demonstration only.
Here she did mouth to mouth breathing for 30 minutes without interruption producing tidal volumes between one and two liters each.
She's using the thumb jaw lift method.
90 percent of our 167 untrained rescuers after one demonstration produced inflations of over 500 milliliters with mouth to mouth breathing during the initial 60 seconds.
94 percent with this method.
87 percent with a hands jaw lift method.
You see in the corner the subject's relative arterial oxygen saturation.
It is 97 percent which is room air control value.
Now we will show you how rapidly hypoxia develops and how rapidly mouth to mouth breathing can re -oxygenate the apneic subject.
The victim is still paralyzed.
Watch the drop of the oxygen saturation in the corner.
30 seconds without breathing and it drops.
80.
Now re -oxygenate.
One, two, three, four, five, six, seven breaths and back to 95 percent.
After about 10 deep inflations at the rapid rate the subject was re -oxygenated.
For maintenance breathing a slower rate is adequate.
Ventilation with expired air could maintain oxygen and carbon dioxide values normal when tidal volumes were at least twice as large as normal.
This is in an adult one liter per breath or more.
Here as few as six to ten inflations per minute maintain the oxygen saturation around 95 percent.
Notice how her left thumb is wrapped with a piece of cloth.
This is a precaution during prolonged mouth -to -mouth breathing when thumb became sore during support of the lower teeth.
We are going to record the end expiratory carbon dioxide concentrations of the rescuer and the subject.
When the subject was breathing spontaneously through the analyzer while conscious we obtained this control curve.
During inspiration the carbon dioxide measured at the mouth is zero.
During expiration it rapidly increases and levels off between five and six percent.
This plateau of the curve indicates the end expiratory carbon dioxide which is the aldeolar carbon dioxide.
Again inspiration and expiration.
Now the analyzer is between the airway and the rescuer.
The arrows indicate the moments when the rescuer blows.
You can see a drop of the carbon dioxide concentration when the rescuers dead space air moves through the analyzer into the victim and the return to a first plateau which indicates the rescuers aldeolar carbon dioxide between three and four percent.
Then during passive expiration of the subject the subject's aldeolar sample appears as a second plateau between four and six percent.
As you see none of the aldeolar values of the subject are greater than the control value indicated by this red line.
Here the rescuer takes a deep breath and blows forcefully.
The air column moving into the victim first contains almost no carbon dioxide.
Here he takes a shallow breath before blowing.
There is no dip to zero.
Here the infrared carbon dioxide analyzer is placed between the mouth -to -mouth airway and the rescuers mouth.
The carbon dioxide tracing is in the corner.
Observe how far to the right the pen moves with each expiration of the subject.
Now deliberate apnea.
The oximeter in the corner shows deoxygenation.
The carbon dioxide tracing would show nothing during apnea because no air is moving.
The oxygen saturation drops.
Watch the carbon dioxide tracing when resuscitation starts.
Now during the first few inflations the pen moved beyond the control value to the right indicating wash out of the accumulated carbon dioxide.
Now the pen stays within control levels.
The lack of the end expiratory plateau indicates too rapid breathing.
The next inflation should not be performed unless the lungs have deflated.
We measured the amount of air blown into the stomach.
Gastric distension may occur during mouth -to -mouth breathing when the mandible is poorly supported or when the inflations are excessively forceful.
Gastric distension proved harmless and preventable.
Sometimes no air was found after 15 minutes of correct mouth -to -mouth breathing.
At other times between thousand and nineteen hundred milliliters were measured.
The air collected in the bag is measured by water displacement.
When during resuscitation the epigastric area protrudes, pressure over the between breaths can expel the air.
A rescuer skilled with endothracheal intubation who carries the proper equipment will find mouth to endothracheal tube breathing to be the most effective expired air method for immediate reoxygenation of an asphyxiated person.
The endothracheal tube makes support of the mandible unnecessary.
The cuff prevents air leakage and gastric distension does not occur.
At this point the succinylcholine infusion is discontinued and the subject is permitted to recover.
He had received a total of 3 ,400 milligrams of succinylcholine within three hours.
Gradual recovery of muscle power occurs within about 30 minutes.
We therefore conclude that the problem of upper airway obstruction in the unconscious person deserves more attention.
Positive pressure breathing may overcome partial obstruction.
When the person is found apneic, immediate reoxygenation is needed.
One should not wait until resuscitation arrives.
Back pressure arm lift and chest pressure arm lift methods of artificial respiration proved unreliable.
With mouth -to -mouth breathing, reoxygenation can be accomplished within seconds by deep inflations through an open airway.
