MECHANICAL VENTILATOR

GLOSARY

Lung: The lungs are a pair of breathing organs located with the chest which remove carbon dioxide from and bring oxygen to the blood. There is a right and left lung.

   

 

            


Breathing:The process of respiration, during which air is  inhaled into the lungs through the mouth or nose due to muscle contraction and then exhaled due to muscle relaxation.

     

Volume: Lung volumes are also known as respiratory volumes. It refers to the volume of gas in the lungs at a given time during the respiratory cycle. Lung capacities are derived from a summation of different lung volumes.

• Tidal Volume(TV): It is the amount of air that can be inhaled or exhaled during one respiratory cycle. 
• Inspiratory Reserve Volume(IRV): It is the amount of air that can be forcibly inhaled after a normal tidal volume. 
• Expiratory Reserve Volume(ERV): It is the volume of air that can be exhaled forcibly after exhalation of normal tidal volume.
• Residual Volume(RV): It is the volume of air remaining in the lungs after maximal exhalation.

 

Expiratory flow: is determined by the magnitude of alveolar pressure and simultaneous total airway resistance. The pressure in the alveoli is the combination of the elastic recoil pressure of the lung and the increased intrapleural pressure produced by expiratory effort.  

  

  Pressure: Air moves by bulk flow from an area of high pressure to low pressure. All pressures in the respiratory system are relative to atmospheric pressure (760mmHg at sea level). Air will move in or out of the lungs depending on the pressure in the alveoli. The body changes the pressure in the alveoli by changing the volume of the lungs. As volume increases pressure decreases and as volume decreases pressure increases. There are two phases of ventilation; inspiration and expiration. 

INTRODUCTION

   Mechanical ventilation is a life support treatment. A mechanical ventilator is a machine that helps people breathe when they are not able to breathe enough on their own. The mechanical ventilator is also called a ventilator, respirator, or breathing machin. This equipment is a therapeutic intervention, in the form of external and temporary prostheses,which is frequently found in patients who are of the emergency department of our hospitals.

The mechanic   ventilator employs a  air delivery system, controlled by an electro valve and a combination control panel interface.The fan acts as a positive airway pressure generator that supplements the active phase of the respiratory cycle . Mechanical ventilation is a procedure for temporarily replacing normal ventilatory function.

MARCO  TEORICO

•  Diagram  the mechanical ventilator works:

• What kind of electro valve can you find in the mechanical ventilator machine? and how do it work? 

   Inspiratory flow regulator – basically, any device which ensures that the respiratory circuit receives the prescribed gas flow. This is usually a solenoid valve. This thing sits in front of the gas supply (either from the wall or from the compressor turbine) and ensures that the patient is only exposed to carefully measured amounts of that gas. Given that the wall gas in ICU piping outlets is supplied at a standard pressure of 400kPa (approximately 4 atmospheres), it is obviously an essential component. 

• Assist-Control Ventilation (ACV): Is a ventilator mode in which the machine delivers the same tidal volume during every inspiration, whether initiated by the ventilator or by the patient. This occurs regardless of the mechanical load on the respiratory system and no matter how strenuous or feeble the inspiratory muscle effort.

 

•  Synchronized Intermittent-Mandatory Ventilation (SIMV):intermittent mandatory ventilation spontaneously initiated by the patient to increase tidal volume to a preset volume, and subsequently synchronized with the patient's respiratory cycle; if the patient makes no respiratory effort, the machine automatically delivers a preset number of breaths by itself.

 

• Pressure-Controlled Ventilation (PCV) - Pressure Support Ventilation (PSV):is a controlled ventilation mode combining  the  advantages  of  Volume  Control    Ventilation  (VCV)  and  Pressure  Control  Ventilation  (PCV) for patients requiring controlled mechanical ventilation. 

  • Volume  Control  Ventilation  (VCV): Has been  the  traditional  controlled  ventilation mode in anesthesia.  In VCV, the ventilator delivers the preset tidal volume  with a constant flow during the preset inspiratory time  at the preset respiratory rate.

    

  • Pressure  Control  Ventilation  (PCV):  The  ventilator  generates  the  preset  pressure during  a  preset  inspiratory  time  at  the  preset  respiratory  rate.  The  pressure  is constant during the inspiratory time and the flow is decelerating.

    

    • Airway pressure relase ventilation (APRV):

    

     

    A mechanical ventilation pressure control mode that uses an inverse relationship ventilation strategy. The configurations listed here are a fundamental explanation of the purpose of the configurations within APRV mode.

    Phigh: this is the inspiratory pressure (as in the pressure control).

    Thigh: this value is the number of seconds during the inhalation phase.

    Tpeep: also known as Tlow, this is the time allotted for expiration.

    FiO2: the fractional percentage of O2 that is added to the supplied air.  

    • Positive end-expiratory pressure:

    

    Pressure profile of a volume-targeted breath in which flow is interrupted at end-inspiration, allowing measurement of the quasi-static properties of the respiratory system.

    PEEP: positive end-expiratory pressure.
    PIP: peak inspiratory pressure.

    • Plat, end-inspiratory plateau pressure: Auto-PEEP, pressure above the set level of PEEP that is generated by dynamic hyperinflation due to incomplete exhalation in the presence of obstructive lung disease.

                          

      ACTIVITY  IN CLASS

The mechanical fan has in its circuit a compressor, an electrovalula and a pressure sensor that are connected to a release module to alternate the outlet and intake of air to the pulmonary simulator, in order to obtain the graphs of volume, pressure and Flow.

After having the system assembled and operating, a graphical interface was made in which obener the corresponding graphs are sought for each parameter, for which the relationship of pressure-volume and the characterization of the pressure sensor were taken into account shown below:

RESULTS

 

In the interface we can observe the graphs corresponding to the volume and flow, obetened through the platform. The volume shows us the amount of air moving between the inside of the lungs and the outside per unit of time, this unit being normally the minute. Its determination is made by the product of the current volume by the respiratory rate.

  BIBLIOGRAPHY

• Hyatt, Robert E. "The interrelationships of pressure, flow, and volume during various respiratory maneuvers in normal and emphysematous subjects." American Review of Respiratory Disease 83.5 (1961): 676-683.https://en.wikibooks.org/wiki/Human_Physiology/The_respiratory_system
• Pruitt, W. C. "Ventilator graphics made easy." RT-MARINA DEL REY- 15.1 (2002): 23-26.https://derangedphysiology.com/main/cicm-primary-exam/required-reading/respiratory-system/Chapter%20531/flow-volume-pressure-resistance.
• Chatburn, Robert L.; Branson R.  "Classification of Mechanical Ventilators." Respiratory Care 37.9 (1992): 1009-1025.https://derangedphysiology.com/main/cicm-primary-exam/required-reading/respiratory-system/Chapter%20531/flow-volume-pressure-resistance.
• Chatburn, Robert L. "Classification of mechanical ventilators and modes of ventilation." Principles and practice of mechanical ventilation. 3rd ed. New York: McGraw-Hill (2012).
• Kacmarek R., Chipman D.; “Basic Principles of Ventilator Machinery.” In Tobin MJ (ed): Principles and Practice of Mechanical Ventilation. New York, McGraw-Hill, 2006 (2nd Ed)  p 53-96
• Chatburn, R.L; Mireles-Cabodevila. E.  “Basic principles of ventilator design.” In Tobin MJ (ed): Principles and Practice of Mechanical Ventilation. New York, McGraw-Hill, 2006 (3rd Ed)  p.65-95
• Mushin, William W., et al. Automatic ventilation of the lungs. ed. Blackwell Scientific Publications, Oxford and Edinburgh, 1969.
• Chatburn, Robert L. "A new system for understanding mechanical ventilators." Respiratory care 36.10 (1991): 1123.
• Chatburn, Robert L. "Fundamentals of mechanical ventilation." Cleveland Heights: Mandu Press Ltd (2003).