Airways under the Vagus nerve control comprises two integrated hemi-circuits
The role of the muscles of the airways walls, under control of the Vagus-Sympathetic nerve, is the performance of cyclic regional modulation, for specific local results and final integration, of currents of atmospheric masses of air, as an Oxygen transporter to the alveoli, followed by its renovation. Sphincters around the opening of the five pulmonary lobes divide the airways into two functional hemi-circuits:
1.The BronchoTracheo-Laryngeal hemi-circuit, responsible for the used air ejection from here to the exterior, followed by its renovation from the Naso-Pharynx and balance before being sucked by the Lung.
2. The pulmonary hemi-circuit, which takes that mass of air in the bronchi, for simultaneous distribution among the alveolo-capillary units as a whole. New ways are opened for research and improvement in health care, prevention, and clinical and therapeutic procedures to prevent accidents, complications and even death.
Return to the content
RESÚMEN EN ESPAÑOL.
El papel de los músculos de las paredes de las vías aéreas, bajo control Vago-Simpático, es la modulación cíclica regional y sectorial de las vías aéreas, para generar resultados parciales específicos y una final integración de corrientes de masas de aire, transportadoras de Oxígenos hasta los alvéolos, seguida de su renovación . Esfínteres alrededor de las bocas de los bronquios lobares principales dividen funcionalmente las vías aéreas en dos hemi-circuitos:
1.El hemi-circuito bronco-tráqueo-laríngeo, responsable del almacenamiento de aire utilizado durante el ciclo precedente, para su eyección hacia el exterior, por acción constrictora, seguida de su renovación desde la naso-faringe, durante su relajación, para su adaptación y balance antes de ser ofrecido a los lóbulos pulmonares.
2. El hemi-circuito de bronquios lobares como un todo, los cuales toman sus respectivas masas de aire fraccionadas, desde los bronquios principales derecho e izquierdo, para su simultánea distribución entre sus respectivas unidades alvéolo-capilares.
Se abren nuevas vías con amplias perspectivas para la investigación científica, dirigidas al mejoramiento de las tácticas y técnicas relativas a la defensa de la Vida y la Salud, tanto en la prevención, como en el estudio clínico y la terapéutica aplicada. y que habran de evitar complicaciones, accidentes y muertes derivadas de errores prevalentes del conocimiento científico aplicado en la practica institucionalizada..
Return to the content
THE RESPIRATORY PULSE. (R. P.) Is the Resultant of the pulmonary autonomic dynamics as detected in the pleural space.
Tissue cells need Oxygen for their metabolism and life, which is supplied by specific transporters of the blood, loading it by gas exchange at the alveolo-capillary units of the Lung.
The natural transporter of Oxygen is a mass of atmospheric air, which must be acclimatised and pressurised before its delivery. The final port of delivery is the alveolo-capillary complex. The farthest port of load is the Naso-Pharynx in connection with the Atmosphere and, transportation is programmed to be achieved in two hemi-circuits simultaneously: The Lung, constituted by the five pulmonary lobes, as the most sophisticated, complex hemi-circuit, for the specific function of gas exchange with the blood and, the Broncho-Tracheo-Larynx hemi-circuit, for modulated circulation of the air streams leading to air renovation. Air circulation into these hemi-circuits is fulfilled in two successive mechanical phases, under the Vagus-Sympathetic command for, contraction-relaxation of the muscles of Reissessen.
For reasons not to be discussed here, the interpretation of this mechanics for air transportation had previously remained unsolved in many respects. Therefore, the Author decided to assume this enterprise from the very moment he discovered and graphed "The Respiratory Pulse" RP in 1978.
The Author considered this discovery of revolutionary importance, since it brought to evidence that the prevailing Theory of Respiration was based on two main concepts now contrasted: 1. The Lung as a passive organ, contrasted by: The Lung is an active organ, under Vagus-Sympathetic command. 2. The Diaphragm as the motor of the Lung, contrasted by: The Diaphragm is the supporting muscle of the base of the Lung, acting under a Vagus-Phrenic reflex of mechanical stimulus. The first graphic proof of the pulmonary owns dynamics is recorded in that transcendental experiment (1. p 126-49).
The concept of the pleural pressure, as another driver of the Lung leading to its expansion, also resulted in being contrasted, since it was also proved that pleural pressure variations is the effect of the pulmonary autonomic structure constriction-retraction expansion, causing increase decrease in the pleural capacity, and conversely proportional decrease-increase in pressure of the pleural content in gas state. Ever since, the Author has been devoted to the re-interpretation of the pulmonary dynamics, concluding in a new theory: "The New Theory of Respiratory Dynamics", published in 1985 2.
This work was followed by the interpretation of the pulmonary dynamics integration with the cardio-circulatory dynamics, as pulmo-cardio circulation of fluids, extending from the cells up to the Atmosphere 3. More recently the Author has started the study of the dynamics and airflow along the Tracheo-Bronchial trees 4.
The background of the present knowledge about airflow is dominated by some common cause-effect reasoning. One of the models in the interpretation of the pattern of breathing was based on tidal volume and frequency of ventilation. Clark and Von Euler. 1970.5 who studied the sequence of events in a breathing cycle in terms of inspiratory time, expiratory time and volume, considering that "The relationship between inspiratory volume and inspiratory duration appeared governed by at least two distinct mechanisms, which operated over different volume ranges". Gardner, W.N.1 977.6 Described the pattern of breathing in terms of the mean expiratory tidal volumes against the mean inspiratory and expiratory duration. R. Painter and D.J.C. Cunningham. 1992.7 consider that in exercise, the peak flow occurred later in inspiration and believes that inspiration is shown as positive and expiration as negative. J. Clement et all. 19 73.8 Consider the pleural pressure and lung static recoil as driving pressures of the expiratory flow. They suggest that the transmural pressures acting across the walls determine the actual volume and diameters of conducting airways.
The aim of the present work is the investigation and demonstration, on the scientific bases of the new parameters discovered and interpreted by the Author, of the mechanics for transportation, modulation and final circulation of the air mass to be used in gas exchange with the blood, followed by its renovation, under autonomous control, in the Broncho-Tracheo-Larynx air passage, as well as in its integration with the Atmosphere on one side and, with the pulmonary lobes, which accomplish the pulmonary dynamics, on the other.
Return to the content
These experiments, as well as all those performed by the Author in more than twenty experimental sessions during the latter eighteen years, have been carried out on intact and spontaneous breathing dogs, anaesthetised with sodic-pentobarbital, 30 mg/kg weight to start with, complementing it if necessary and, taking permanent care about the conditions of the animal, avoiding the minimal suffering.
Each experimental session ends with the injection of a lethal dose of a drug such as d-tubocurarine, previously used in testing its effect on respiration, everything in accordance with institutional guidelines. In order to obtain the graph of the most physiological airflow pattern under anaesthesia, the first experiment illustrating the present work was performed by means of tracheal puncture with a needle connected to the transducer. fig.1.
The second experiment programmed to obtain simultaneous graphs of the tracheal airflow and the tracheal wall own dynamics, fig.2. was carried out, as in similar cases, introducing a wide hard walled cannula, provided with a rubber cuff around it, through the Glottis, filling it then with water, up to contact with the interior surface of the Trachea, then connecting it and the lumen of the cannula with suitable transducers, these then connected with an "Acquire" acquisition data and computer device.
In order to obtain simultaneous graphs of the airflow and RP as shown in fig. 3, during the same second experiment, a small rubber balloon was placed in the pleural space, through a tiny incision at the 6th intercostal space, then emptying the small possible pneumothorax caused, finally filling the balloon with two c.c. of water, and connecting it to another transducer.
Return to the content
THE BRONCHO-TRACHEO-LARYNGEAL AIRFLOW IS ACHIEVED IN FOUR SUCCESSIVE MECHANICAL EVENTS.
The mechanics responsible for tracheal airflow is relative to a system of air passages obeying an anatomical and structural designs that function under the Vagus nerve control, to achieve its role in the renovation of the air used by the pulmonary lobes in gas exchange with the blood.
Therefore, airflow is relative to masses of air at different pressures displaced along elastic passages provided with autonomic muscles in their walls. These passages are subject to capacity variations by means of cyclic contraction-relaxation of their muscles. Consequently, the simplest method to understand the airflow mechanics is the application of the Boyle-Mariotte Law 9; bearing always in mind the essence of the vital function of Respiration, fulfilled by two simultaneous processes: gas exchange with the blood and air renovation from the Atmosphere.
Fig. 1. Tracheal airflow model graph of pressure variations, monitored by tracheal puncture, in the anaesthetised dog, with spontaneous respiration. Two phases are well defined: an ascending slope -marked 1-2; and a descending slope, marked 2-5; this latter showing three successive events. First, a rather slow falls of pressure, marked 2-3. Second, a plateau of dynamic balance of pressure marked 3-4. Third, a new falls of pressure, marked 4-5.
Fig 1. shows the graph of one physiological cycle of the airflow pressure variations produced by the above said mechanics, as the model to be analysed here. This cycle has a period of 6 seconds, for a rhythm of 10 cycles/min.
The full wave shows two phases: The ascending slope marked 1-2 and, the descending slope marked 2-5.
The ascending slope starts at the pressure of -38.21 cmH2 O to end at a peak of +6.23 cm/H2 O, which means a pressure increase of 44.44 cm/H2 O, in only 1.14 seconds. A difference in the outline of this slope can be observed in its lower half part, which is irregular and slow, in relation to the upper half, which is faster and straighter. See the mathematical analysis in table 1.
This ascending slope signifies a pressure increase in the flowing mass of air, relative to three main mechanical factors: 1.The arrival of a volume-mass of warm used air coming from the lobes of the Lung. 2. A decrease in the airway capacity, due to the contraction of the Reissessens muscles, and 3.Simultaneous closure of the Glottis, resulting in the closure of the upper end of the airway. Hence, the arriving air is temporarily stored and pressurised to enable its exit as a warm stream along the cooler air filling the Naso-Pharynx, when conditions are given.
The second phase of the wave is a descending slope, which reaches a similar value to that of the starting point of the cycle, giving way to a new cycle. This phase lasts 4.88 seconds, which means 4.28 times, 375.4% slower than the ascending slope, and shows three noticeable events.
The first event, marked 2-3, is a rather fast decrease in pressure, from the peak at +6.22 to -10 cm/H2 O, which means a fall in pressure of 16.22 cm/H2 O in about 1.10 seconds, shaping the "neck" of the wave.
The second event, marked 3-4 is a plateau at about -10 cm/H2 O with a duration of 3 seconds; 2.72 times, 272.7% longer than the first event.
The third event is a new fall in pressure, faster than the first one, going from -10 to -40 cm/H2 O, which means a descent in pressure of 30 cm/H2 O in only 0.78 seconds, that is, 13.78 Cm/H2O, 84.95% more tan the first event, taking place during a shorter time, 70.9 % of the former, suggesting the presence of new factors for specific tasks.
|Time (s)||Airflow (Cm/H20)||Time (s)||Airflow (Cm/H20)|
Table 1. Airflow ascending
slope pressure variations. Shows the data of the electronic sheet
corresponding to the ascending slope of the airflow cycle of fig.
1, with a sequence of pressure variations each 0.02 second. Its
full extension has been divided into four equal parts of 0.28
seconds each for analysis.
The first part shows successive fluctuations in increase and decrease in pressure, with a total increase of 1.34 cm/H2O, and a media value of 0.04 cm/H2O each 0.01 seconds, and 0.09% of the total increase.
The second part shows similar fluctuations as in the former one, although with a major increase, which sum 3.9 cm/H2O, with a media of 0.13 cm /H2O each 0.01 second and a relative increment with the former period of 291 % and 0.77 % in relation to the total increase.
The third period shows a sustained increment in pressure, without fluctuations, with an increase of 8.67 Cm/H2O, for a media of 0.30 cm/H2O each 0.01 second, representing an increase of 4.77, 222.3 % and, 19.5% of the total increase.
Finally, the fourth period shows an increase of 28.32 cm/H2O with a media of 1,1 cm/H2O each 0.01 second, a relative increase of 326.64 % in relation to the former one, which also means 63.72 % from the total increase. It is concluded that the first half of the ascending slope shows permanent fluctuations with slow progressive tendency to the increase in pressure, although only the 12.46 % of the total pressure increase is reached, which means that the remaining 87.54 % is achieved during the second half of the period. Observe that a conceptual synthesis would be similar to the observations made in the graph.
The physiological interpretation of these events, from the perspective of the new concepts demonstrated in the "New Theory of Respiratory Dynamics" (2) is very important because of their implicit consequences. Thus, the starting point of the cycle corresponds to the pulmonary lobes active expelling, of the air used during the whole cycle of gas exchange with the blood just finished (4, pages 2-13). The airways muscles as a whole, start their contraction simultaneously, under the Vagus discharge, showing an early period, to then become a firm contraction at the second part of the ascending slope, also closing the airways opening, by contraction of the muscles of the Glottis.
Contraction is followed by relaxation and, the first manifestation of this, at early relaxation, is the beginning of the pressure drop, which means the maximal resistance at which the initial relaxation of the Glottis enables the exit of the pressurised air to the Pharynx, leading to the exterior as a jet of warm air. We now know that this resistance is overcome when the air pressure reaches +6.22 cm/H2 O for this model. This event corresponds to Expiration in general sense, which is the first programmed objective effect of the dynamics under study.
A new local imbalance is produced by the total exit of the expired air and wider relaxation of the Glottis, as well as of the passage walls, causing a descent of the cooler mass of pre-acclimatised air in the Naso-Pharynx, to balance volume-mass, temperature and tension with the remaining air-mass in the air-passage. This process is represented by the steady event shown by the plateau, lasting the time required achieving the physiological conditions needed by the lobes, before being ejected towards the alveoli. The air mass descent from the Naso-Pharynx is followed by a similar mass of atmospheric air to fill the space just left free, to remain there up to the next cycle. This latter mechanical process corresponds to Inspiration in general sense.
The third event represents the effects of new mechanical conditions relative to maximal relaxation of the Reissessen muscles, with the following consequences: The airless bronchioles of the lobes now exert a sucking force from the common, left and right bronchus now full with acclimatised air. Consequently this event depletes the contained air in the extra-pulmonary air-passage, thus completing a physiological, autonomic, cycle of contraction-relaxation, with two consequences for the Lung: the reception, by the right and left bronchi, of the air mass used by the lobes, at the beginning of this cycle, and the supply of a similar mass at the end of the same cycle at this level.
Conditions are now given to start a new cycle: the lobes, for gas exchange with the blood during this cycle, using its formerly renewed air and, the extra-pulmonary airways in renovating the air used by the lobes during the former period, with air at the Naso-Pharynx, to be used by the lobes during the next period. Note the overlapping of processes linking the cycle under analysis with the former and the next ones, for steady balance of vital conditions for Life.
Return to the content
AIRWAY WALL DYNAMICS IS DETERMINANT IN THE FOUR EVENTS IN THE AIRFLOW WAVE.
To perform this demonstration, a change in the technique has been made, relative to that of the former experiment on the same dog, as explained in Methods.
Fig. 2. Tracheal airflow, blue heavy line, and tracheal wall magenta line, simultaneous graphs of pressure variations.
The analysis of the airflow graph in figure 2, solid heavy line, in itself as in relation to fig. 1, allows us to observe:
The graph of pressure variations generated by the tracheal wall -dashed line- shows a similar shape to that of the airflow, the values of its pressure variations range being lower, going from -15 to +8 cm/H2 O-. This cyclic pressure variations monitored by means of the rubber cuff full of water contacting the interior surface of the tracheal wall means that the surrounding wall is the subject of cyclic contraction-relaxation, which also means decrease-increase in the air-passage capacity, with simultaneous variations in volume-pressure in the contained mass of air. Therefore, the tracheal wall is the modulator factor for the airflow pressure variations at this level, as shown in fig. 1, with physiological conditions and, fig.2. with mechanical obstruction of the air passage.
Now again, the opening of the Pharynx is also the site of the Glottis, which is also under Vagus control; hence, the muscles of the Glottis are also subject to cyclic contraction-relaxation causing closure-opening of the air passage, with alternating exit of the repressed air and renewal with a similar mass, from the Naso-Pharynx. Other investigators have attributed different interpretations to the role of the Glottis, in accordance with their methods and theoretical referential concepts. (11 and 12)
In short, the Author concludes that the autonomous muscular contraction of the air passage under the Vagus discharge, here including the Glottis, causes a decrease in its capacity, with simultaneous closure of the Glottis, which causes a temporary retention of the air flow coming from the pulmonary lobes, while increasing its pressure, as far as the beginning of the Glottis relaxation, allowing the pressurised mass of air to balance and surpass the resistance opposed by the Glottis, following its exit to the exterior as a jet of air, in the programmed time. The following wider opening of the Glottis, jointly with relaxation of the passage walls of the now airless capacity, creates a sucking force for its filling with the pre-acclimatised air in the Naso-Pharynx, up to the total balance in its new physical conditions, to be then also sucked by a new force exerted by the lobes, from its other end.
Return to the content
THE PULMONARY DYNAMICS IS LEADER IN THE PERFORMANCE OF THE RESPIRATORY CYCLES.
Figure 3., obtained under the same experimental conditions as fig 2, in which a small rubber balloon making contact with the pulmonary surface and filled with water, is the media for detecting the pressure variations generated by the Lung dynamics and transmitted to its pleural surface, shows simultaneous graphs of the airflow -heavy solid line- and that of the pulmonary dynamics (RP) -dashed line-.
Fig. 3. Tracheal airflow graph, blue solid heavy line, and simultaneous Respiratory Pulse graph, red line.
OBSERVATIONS AND INTERPRETATION.
The two waves of pressure are synchronous and their general shape is similar, both being generated by action of the Vagus Sympathetic nerve, as we now know (2. pages 88-98).
The wave of the RP shows its own different contour, proved by the Author to be caused by the specific dynamics leading to gas exchange with the blood, which displays a Sympathetic rhythm, in order to integrate the pulmonary dynamics with that of the Heart, enabling the simultaneous arrival of proportional masses of blood and air to be subjected to gas exchange. (2 pp. 76-88).
The pressure values of the waves are different, and the RP pressure is always greater, since it is the dynamics performed by the pulmonary lobes, leader of the whole physiological process to achieve air renovation for themselves with an ultimate end to gas exchange with the blood, all within their thoracic ensemble and, the tracheal airflow is a consequence of this dynamics, although with modulation by the Broncho-Tracheo-Larynx wall, for the purposes of air renovation from the exterior, as is being studied here
It is very important to bear in mind, at this moment, that the pressure detector for each wave of pressure is placed in each opposite end or pole of the total airways circuit, that is to say, the upper part of the Trachea on one side and, the pleural surface of the Lung on the other; consequently, the two waves reveal Resultants of simultaneous dynamics in the two poles of the autonomous airways system and, as they are results of physiological responses to the Vagus-Sympathetic discharge, on air masses to be displaced by means of contraction relaxation of the airways muscles, it results evident that there must be a simultaneous displacement of two different masses of air in opposite senses.
This latter observation is of transcendental importance, since when ratifying, from another perspective, conclusions of the Authors former works, reveals a fact that signifies a revolutionary conceptual interpretation of the air circulation between the Atmosphere and the alveoli to achieve gas exchange with the blood during each ventilatory cycle.
This observation makes it patently clear that there must be a point or points in the total airflow circuit where a functional segmentation or programmed, cyclic autonomic division in the lumen of the way is produced, impelling the masses of air under the action of simultaneous forces, to follow the sense of lesser resistance.
As we now know, by the evidence of the graphs, those senses are: the surface of the pulmonary lobes, the site of the lobular-alveolo-capillary units, on one side, and the Tracheo-Larynx on the other and, as each lobar tree is rooted in its corresponding main bronchus, right or left, where they have their openings for their own taking and delivery of air, we have no doubt whatsoever when placing here, at these openings, the above referred to functional cyclic closure determining the cyclic division of the whole airflow circuit into two functional hemi-circuits, one comprising the totality of the pulmonary capacity, also subdivided into five independent but integrated lobar circuits as one unit, and the other, comprised by the broncho-tracheo-laryngeal airways, which serve as a circulation passage and cyclic storage of the masses of warm used air, coming immediately from the lobes and, farther on from the lobular-alveolo-capillary units, before following their course, as a total mass, during the event studied here, leading to its exit as Expiration.
This total circulation of air, as described above, requires the presence of true sphincters in the openings of the lobar main bronchi. Therefore, I define as real sphincters those structures described and defined by Miller as "Sphincter-like"13.
It should be clear that the tracheal airflow cycle, as analysed here, is a local process, it neither traduces the whole dynamics of a respiratory cycle, nor even of a cycle of breath, although it has two phases simultaneous with those and even with equal duration.
This is only a cyclic partial process during the same period of the whole respiratory cycle, for reception, by the right and left bronchi, of the air-masses used by the lobes during their former dynamic cycle, to then be pressurised in this passage, in order to enable its exit towards the Naso-Pharynx in a timed period, as exchange with a similar mass of renewed air, to acclimatise and pressurise it to then be delivered up to the openings of the lobes, which will start a new cycle for gas exchange with the blood..
Return to the content
Return to the content
REFERENCES AND NOTES
Return to the content
Return to The Scientific and Social Matter