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In her teenage years is when she started smoking. “It was the cool thing to do,” she stated. Eventually she found herself smoking up to two packs a day. According to her biography, she started feeling the side effects at the age of 25. When she reached the age of 40 she was diagnosed with oral cancer and started her radiation therapy. However, with the radiation therapy she still finds herself lighting up a cigarette. In the same year she had another diagnosis which was throat cancer and her doctor recommended to remove her larynx. She was able to speak with an artificial voice box. Unfortunately, she passed away at the age of 53 in the year of 2013. Before she passed, she shared her story to the public and helped move people to stop smoking before it’s too late! Michael is a veteran that is diagnosed with COPD at the age of 44. He started smoking at the age of 9 when his sister handed him a cigarette stick. “Smoking was something I did to fit in,” he stated. Even though some of his family died because of tobacco usage he still continues to smoke. He attempted to quit smoking but he was never really successful. At the age of 52 was the year he finally stopped smoking because of his wake up call. He awoke struggling to breathe and ended up in the ambulance thinking if he’s going to live or not. He lives, and had a surgery to remove the diseased part of his lungs. Now, continues to fight his battles on improving his health to be with his daughter and spends time with his grandchildren. DURING INSPIRATION: Elevation of the ribs by external intercostals and the contraction of the diaphragm will increase our intra-thoracic volume. Our bronchial airways in a healthy lung will lengthen to increase diameter (passive dilation). Increase in volume will decrease in intrapulmonary pressure. Decrease in intrapulmonary pressure creates a negative pressure gradient relative to atmospheric pressure. Intra-pleural pressure will increase in negativity. Air pressure changes during ventilation: P(atm) > P (alveolar) air moves into the lungs. = Inspiration DURING EXHALATION: Lung will return to its normal state or passive constriction. Internal intercostals and abdominalis will start to compress which decreases the intra-thoracic volume. Decrease in volume creates an increase in intrapulmonary pressure. Increase in intrapulmonary pressure creates a positive pressure gradient relative to the atmospheric pressure. Intra-pleural pressure will be less negative. Air pressure changes during ventilation: P(alveolar) > P(atm) air moves out of the lung. =Expiration In a quiet breath the diaphragm and external muscles contract during inhalation while exhalation is a passive process. As the lungs change in transmural pressures, they reflect a force that is needed to battle airflow components. › Raw and CL RAW: the air has contact with the airway walls where there’s narrowing of airways due to a disease/infection (e.g. asthma) leading to an excessive use of energy to breath. CL :(100-200cmH20); where there’s distensibility of the lung tissue. When the lungs have an increased compliance in turn they will have a decrease in elastance and visa-versa. Compliance=V/P & Elastance=P/V Compliance: measures the ease of inflation or distendibility of which the lungs can stretch. Increased Compliance = Easily inflated lungs Decreased Compliance = Lungs are becoming stiff Elastance: measures lung stiiffness. reciprocal of compliance. Increased elastance = Decreased compliance = Stiff Lungs Decreased elastance – Increased compliance = Easily inflatable lungs Measured during a period of gas flow or normal breathing. Therefore, it is influenced by the patients’ lungs, chest wall compliance and patient-ventilator circuit. Normal lungs’ lung compliance and dynamic compliance ratio is 1:1. If patient have obstructed lungs, it would show a decrease in dynamic compliance due to the alveoli distal to obstruction and causes insufficient “filling” time to its potential capacity. Dynamic compliance can be calculated with the following equation: VT PIP – PEEP Vt = Tidal Volume PIP = Peak Inspiratory Pressure PEEP = Positive Pressure *** We subtract PEEP to get the actual change in pressure *** I. Airway Resistance (RAW) measurement of frictional forces that must be overcome during breathing OR in simple terms, anything that affects flow. Two types of flow: Laminar vs Turbulent Flow. Laminar Flow is when gas molecules travels in an orderly manner. Produced when inputting correct flow rates or by removal of an obstruction. Turbulent Flow is the complete opposite of laminar flow. It is chaotic and it is usually caused by an obstruction or excessive flow rates. Poiseuille’s Law can be written as: V= ∆Pr4π 8ln V = Flow ∆P = Change in pressure l = tube length n = Gas or fluid viscosity r = tube radius 8/π = constant This law is telling us that flow, is directly proportional to pressure and r4 (flow is a function of a 4th power of the radius). However, flow is indirectly proportional to length and viscosity of the tube. Why Poiseuille’s Law? His law will help us recognize changes in the airway diameter and length affects the pressure and flow. Airway Resistance (RAW) is defined as the pressure difference between mouth and alveoli divided by the flow rate. Raw is calculated by the following: Raw = ∆P (cmH20) Flow (L/sec) Applying to mechanical ventilation Raw = PIP – Pplat Flow Increased Resistance will be due to: Bronchospasm – abnormal contraction of smooth muscle in bronchi causing obstruction or narrowing in the airway. Asthma or Chronic Bronchitis – Inflammation of airways causing obstruction and narrowing of the diameter. Secretions – will cause obstruction and the viscosity of it may lead to immobility. Patient with increased work of breathing and showing usage of accessory muscles and possible diaphoresis. By auscultation, patient’s breath sounds may sound wheezing, ronchi or stridor, if ausculating on throat. *** Before fixing the problem, make sure to asses your patients correctly. For bronchospasms, caused by asthma or chronic bronchitis - Treat with bronchodilators, if severe treat with corticosteroids. For secretions - Suction if needed, or some coughing techniques, mucolytics or proper humidification. Stridor indicates edema or inflammation - Cool mist Biting endotracheal tube Kinked ventilator circuit Inappropriate tube size (too small) for the patient’s airway Condensation in ventilator circuit. SOLUTIONS : Insert a bite block in a patient’s mouth Make sure the circuits are hung nicely on the hanger and away from any thing that will cause tangle or possible disconnection of the circuit. Switch to appropriate size for the patient. Make sure to drain any condensation that builds up in the circuit in the reservoir bag. Peak Inspiratory Pressure (PIP) is defined as pressure needed to overcome RAW and it reflects on the conductive airways. Therefore, PIP is directly proportional to RAW. When assessing RAW during a ventilator check make sure to consider PIP. Also tidal volume (Vt), it is not quite as related to RAW as PIP, but decreased values of Vt will show when RAW is present due to volume not fully delivered because of obstructed areas. In the Pressure – Volume Loop on a ventilator, the picture to the right will show that RAW is present. II. Static Compliance It reflects on the distendibility of small airway or the elasticity of lung tissues. We keep our lungs inflated even if we exhale with negative intrapleural pressure because of the alveolar surface tension. Our type II alveolar cells will secret out pulmonary surfactant that helps prevent collapsed alveoli and helps stabilizes alveoli. Inadequate production of pulmonary surfactant will lead to stiff lungs which would be difficult to perform breathing. When we measure static compliance (Cstat) it should be performed with no air flow, or by pressing down the “inspiration hold” on a ventilator (the name varies on different ventilators) to get the appropriate plateau time (0.5 – 1 sec). To identify an adequate plateau pressure on a ventilator graphic, it’s best to observe it on a Pressure – Time Curve (picture on top). During a breath hold, Pplat or pressure in the alveoli will depress through the pores of kohn, canals of lambert and channels of martin. Pplat or plateau pressure is needed to overcome elastic resistance (transalveolar pressure). Static Compliance can be calculated as: Vt Pplat – PEEP Vt – Tidal volume Pplat – Plateau pressure PEEP – Positive pressure *** According to the formula static compliance is inversely proprotional to plateau pressure. *** We subtract PEEP to get the actual change in pressure *** If Plateau pressure and static compliance are inversely proportional then: Decreased Static Compliance = Increased Plateau Pressure will be due to: Pneumonia Pneumothorax Loss of surfactant Atelactasis Pulmonary Edema Pleural Effusion Neuromuscular disease The examples above will make it more difficult for lungs to inflate due to the restrictive problem. Increased Static Compliance = Decreased Plateau Pressure will be due to: Emphysema – because there is greater dispersion of air in alveoli due to elasticity loss. Airway Resistance (RAW): 6 cm H20 (intubated patients) Dynamic Compliance (Cdyn): 60 – 100 cm H20 (patient w/o ventilatory support) 30 – 40 cm H20 ( patient w/ ventilatory support) Static Compliance (Cstat): 70 – 100 cm H20 (patient w/o ventilatory support) < 40 cm H20 (patient w/ ventilatory support) Terry and Michael’s Story Why would having chronic obstruction and highly compliant lungs would make it harder for them to breath out? The lungs have been overstretched making it easy to inflate, leading to low elastic recoil and working harder to force air out. Since they have an increase in compliance, they also have an increase in static lung volume (TLC,FRC and RV) as well as an increase in Raw. EMPHYSEMA disappearing lung disease smoking/genetically inherited alveolar wall destruction EM of healthy lung tissue lung compliance [ floppy lungs] EM of emphysematous lungs Decreased dynamic compliance with stable static compliance: Your PIP will show an increase value on the vent, meaning there is an increase in RAW which could indicate secretions or bronchospasms. Increased dynamic compliance with stable static compliance: PIP will show a decreased value on the vent, which could mean that there is an improvement of RAW indicating: removal of any obstruction. Decreased dynamic compliance with a decreased static compliance: PIP and Pplat on the vent will both show an increase in value and could indicate a combination of decreased compliance with an increase in RAW. Increased dynamic compliance with increased static compliance: PIP and Pplat on the vent will both show a decreased value indicating improved compliance and RAW. Remember that if there is a major change in dynamic compliance and a minor change in static compliance assume that it is a RAW or conductive airway problem! THE END!! http://www.cdc.gov/tobacco/campaign/tips/stories/terrie-biography.html http://www.cdc.gov/tobacco/campaign/tips/stories/michael-biography.html http://apbrwww5.apsu.edu/thompsonj/Anatomy%20&%20Physiology/2020/2020%20Exa m%20Reviews/Exam%203/CH22%20Breathing.htm http://www.respiratorytherapyfiles.net/mechanical-ventilation.html - physiology of ventilation - airway resitance Des Jardins, Cardiopulmonary Anatomy and Physiology, 5th ed. Page, 92 – 98, 102. Print. Cairo, J.M. Pilbeam’s Mechanical Ventilation Physiological and Clinical Applications. 5th ed. Page140. Print. Resistance and Compliance powerpoint By: Martin T. Kevin. BVE, RRT, RCP. Static Compliance powerpoint By: Bobbie Jimenez and Sue Trapp www.google.com for the pictures