Mechanical Ventilation Basics for Respiratory Therapy Students

[00:00:00]mechanical ventilation is a life-saving  intervention for patients who are unable to breathe on their own ventilators use positive  pressure to deliver oxygenated air into the lungs so that gas exchange can occur as I'm sure you  are aware this is a complex topic but it must be understood by respiratory therapists and  medical professionals who care for patients in critical condition the good news is you're  in the right place because this video will provide a comprehensive overview of mechanical  ventilation and the basics of how ventilators work so if you're ready let's get into it as  previously mentioned mechanical ventilation involves the use of a machine to help a patient  who is unable to breathe spontaneously therefore it is indicated for patients who are unable  to maintain adequate ventilation ventilation is the process of taking in oxygen during  inhalation while removing carbon dioxide during exhalation when a patient is unable to  do this on their own a ventilator can be used to assist with or completely take over the  ventilatory process now let's talk about the indications some of the most common reasons  why a patient may require ventilation include insufficient oxygenation when a patient is  not receiving enough oxygen it can impact the functionality of tissues and vital organs of  the body mechanical ventilation can help deliver oxygen to the lungs which is then distributed  throughout the body insufficient ventilation when a patient is not removing enough carbon dioxide  from their body it results in increased acidity of the blood mechanical ventilation helps the  patient remove carbon dioxide during exhalation an acute lung injury this is an injury to  the lungs that occurs from an acute event such as sepsis pneumonia aspiration or drum severe  asthma Deering and asthma exacerbation the Airways constrict and make it difficult to move air in  and out of the lungs this can lead to respiratory failure which often requires ventilatory support  severe hypotension conditions that cause extremely low blood pressure such as shock sepsis and  CHF often require mechanical ventilation inability to protect the airway when a  patient is at risk of aspirating secretions into the lungs they may require intubation and  mechanical ventilation to protect their Airway and an upper Airway obstruction conditions  that cause upper Airway obstructions such as epiclottitis and laryngeal edema can prevent  patients from being able to move air into the lungs therefore mechanical ventilation  can help bypass the obstruction in general mechanical ventilation is indicated whenever a  patient's spontaneous breathing is not adequate to sustain life in such a case a ventilator would  be used to provide breathing support until the patient's underlying condition is reversed  now let's talk about the contraindications a patient cannot survive without adequate  ventilation and oxygenation therefore there are no true contraindications for mechanical ventilation  however there may be some circumstances where a patient chooses not to receive mechanical  ventilation such as when they have a DNR order in place this means that the patient legally  wishes not to receive life-saving interventions in these cases the patient's goals of care must  be respected now it's time to get into the weeds just a bit the next topic we need to cover  is the principles of mechanical ventilation practitioners must learn and understand the  basic principles in order to administer support to patients in need this includes the following  ventilation which is the process of moving air into and out of the locks oxygenation which is the  process of absorbing oxygen into the bloodstream lung compliance which is the longest ability to  expand and contract Airway resistance which is the impedance of airflow through the respiratory  tract dead space ventilation which is the volume of ventilated air that does not participate in  gas exchange and respiratory failure which is the inability of the lungs to oxygenate the  blood or remove carbon dioxide from the body each principle is important in determining the  amount of ventilatory support that is delivered to the patient by the machine and speaking of  machines what exactly is a mechanical ventilator a ventilator is a breathing machine  that uses positive pressure to deliver ventilatory breaths to patients who are in need  of assistance the machine consists of several parts that work together to generate positive  pressure that helps Force air into the lungs mechanical ventilation is an intervention that  can provide short or long-term support while the patient's underlying condition is treated it is  often indicated for patients with cardiopulmonary disorders but is also common in post-operative  patients who are recovering from anesthesia as previously mentioned ventilators work by  using positive pressure to deliver breaths to the patient however an artificial Airway must be  inserted into the patient strachea before being connected to the machine this process is known  as intubation which involves the insertion of an endotracheal tube through the mouth and into the  trachea once the tube is in place it establishes a link between the patient and the ventilator so  that positive pressure breaths can be delivered and one important thing to remember is that  ventilators are not used to heal and treat a patient of their underlying disease rather they  are used to provide breathing support until the patient is stable and treated with medications  and other modalities now let's talk about the benefits there are many benefits for patients who  are receiving mechanical ventilation including the following the first benefit is that it decreases  work of breathing the ventilator assists with the patient's breathing which can help to decrease the  amount of energy and work required for each breath it maintains adequate oxygenation the ventilator  can deliver an fio2 of up to 100 to help with oxygenation it can also deliver peep or  positive end expiratory pressure which is helpful in patients with refractory hypoxemia  it helps remove carbon dioxide the ventilator can help the patient remove CO2 from their body  with an increased respiratory rate or tidal volume and it provides stability the ventilator helps  keep the patient stable allowing medications and other modalities to reverse their underlying  condition the benefits of mechanical ventilation often far outweigh the risk which is why  it is such a common intervention in the field of Respiratory Care however there  are some complications that can occur some of the most common risks and complications  of mechanical ventilation include the following first is Barrel trauma which is an injury to lung  tissue that results in alveolar over distention caused by increased levels of pressure ventilator  Associated pneumonia which is a type of pneumonia that develops 48 hours or more after a patient  has been intubated and placed on the ventilator peep which is a complication of mechanical  ventilation that occurs when a positive pressure remains in the alveoli at the end  exhalation phase of the breathing cycle oxygen toxicity which is a type of cell damage  that can occur when a patient is exposed to high levels of oxygen for an extended period of time  and a ventilator-induced lung injury which is an acute lung injury that occurs while a patient  is receiving mechanical ventilatory support with that said these risks and complications can  be minimized with proper care and monitoring by medical professionals next we need to talk  about the types there are four primary types of mechanical ventilation each with its own  indications settings contraindications and risks this includes the following positive pressure  negative pressure invasive and non-invasive positive pressure ventilation is the most common  type it's often referred to as conventional mechanical ventilation and is generally what  people are talking about when they say that someone is on the ventilator this type works by  using positive pressure that is greater than the atmospheric pressure to push air into the lungs  the air then fills the alveoli where the exchange of oxygen and carbon dioxide takes place the  next type is negative pressure ventilation this type is not as common as positive pressure  but it may still be used in certain situations it works by generating negative pressure outside of  the thoracic cavity that is less than atmospheric pressure as a result air moves from an area of  higher pressure or outside the body to an area of lower pressure which is inside the lungs some  examples of negative pressure ventilation include the iron lung which is a negative pressure  ventilator that was invented in the 1920s primarily to treat patients with polio and Keras  ventilation which is a type of negative pressure ventilation that is delivered through a tight  fitting garment that covers the chest and abdomen like I said not quite as common but still  worth mentioning and the next type is invasive mechanical ventilation this type involves the  insertion of an artificial Airway into the trachea which establishes a direct connection between the  ventilator and the patient's lungs there are two primary types of artificial Airways that can be  used endotracheal tubes and tracheostomy tubes an endotracheal or ET tube is a long thin tube  that is inserted through the nose or mouth and then passed down the throat into the trachea a  tracheostomy tube on the other hand is a shorter tube that is inserted through a small incision  in the neck and then directly into the trachea and finally the last type that I want to mention  is non-invasive ventilation this is a type of ventilatory support that does not require the  insertion of an artificial Airway instead it requires the use of a face mask that creates  a Tight Seal over the patient's nose or mouth this allows the machine to force oxygen-rich air  into the patient's lungs using positive pressure the two primary types of non-invasive ventilation  include CPAP and BiPAP which we will talk more about later on in this video but in general  non-invasive ventilation is indicated to improve oxygenation and ventilation and to provide relief  for respiratory distress prior to intubation and conventional mechanical ventilation moving right  along now let's talk about the ventilator modes a ventilator mode is a setting that determines how  the machine will deliver breath to the patient the characteristics of each mode determine how  the ventilator functions in general there are two primary control variables in mechanical  ventilation volume control and pressure control volume control is a type of ventilation where  the delivered volume can be set or controlled by the operator since the delivered  volume is fixed the patient's Peak inspiratory pressure will vary depending  on their lung compliance and air weight resistance the primary advantage  of volume controlled ventilation is that a set volume allows the operator to  regulate the patient's minute ventilation pressure control on the other hand is a type of  ventilation where the delivered level of pressure can be set or controlled by the operator since  the delivered pressure is fixed the patient's tidal volume will vary depending on their lung  compliance and Airway resistance the primary advantage of pressure controlled ventilation is  that it protects the lungs from over inflation due to too much pressure which prevents Barrel  trauma and ventilator-induced lung injuries now it's time to dive deeper into the different  types of ventilator moats including assist control simv pressure support CPAP volume support control  mode airway pressure release ventilation mandatory minute ventilation inverse ratio ventilation and  high frequency oscillatory ventilation each mode is different and has its own characteristics this  includes unique settings and how the machine will deliver breaths to the patient we have a separate  video that covers all the ventilator modes in more detail so definitely check that out if you want  to learn more but for this video I still want to cover the two primary ventilator modes as  they are assist control and simv or synchronous intermittent mandatory ventilation the assist  control mode is used to deliver a minimum number of preset mandatory breaths by the ventilator  but the patient can also trigger assisted breaths therefore the patient can make an effort to  breathe and the Machine will use positive pressure to assist in delivering a breath this  mode provides full ventilatory support therefore it is commonly used when mechanical ventilation is  first initiated this mode helps keep the patient's work of breathing requirement very low the other  primary mode of mechanical ventilation is simv this mode delivers a preset number of mandatory  breasts but it also allows the patient to initiate spontaneous breasts in between the preset breaths  since the patient is able to initiate spontaneous breaths it means that they are contributing to  some of their minute vigilation therefore simv is indicated when a patient only needs partial  of insulatory support so now that we've covered the modes next we need to talk about my second  favorite topic which is the ventilator settings ventilator settings are the specific parameters  that are set on the machine in order to provide the patient with optimal ventilation the most  common types of ventilator settings include first is the moat which as I just discussed is the  primary setting that determines how the ventilator functions next is the title void which is the  volume of air that is delivered with each breath the frequency rate which is the number  of breaths that are delivered per minute fio2 which is the percentage of inspired  oxygen that is being delivered to the patient flow rate which is the rate at which a volume  of air is being delivered to the patient next is the IE ratio which is the ratio of the  inspiratory portion compared to the expiratory portion of the breathing cycle sensitivity which  is the setting that determines how much effort or negative pressure the patient must generate in  order to trigger a breath to be delivered then you have the peep or positive and expiratory pressure  that is applied at the end of the expiratory phase in order to prevent alveolar collapse and you have  the ventilator alarms all ventilators are equipped with alarms that act as safety mechanisms to alert  caregivers when there is a problem related to the patient ventilator interaction each ventilator  setting has different characteristics that must be controlled or adjusted to determine the  amount of support that is delivered to the patient but before we can even input any modes or settings  we must first learn about the initiation of mechanical ventilation this is a complex process  that requires coordinated efforts of doctors and respiratory therapists the decision to use  mechanical ventilation is based on the patient's respiratory status and the underlying cause of  respiratory failure which means that you must learn about the initial ventilator settings once  it has been determined that mechanical ventilation is needed the operator must know how to properly  input the initial ventilator settings including the following first is the mode which the most  common initial ventilator modes are assist control and simv however any operational mode will work  when setting up the initial ventilator settings next is the title volume which the initial title  volume should be set at six to eight milliliters per kilogram of the patient's ideal body weight  the initial frequency is 10 to 20 breaths per minute the initial fio2 should be set at 30 to 60  percent or at the previous fio2 that the patient was on prior to intubation and this could be up  to 100 percent the initial flow rate should be set between 40 to 60 liters per minute the initial  IE ratio should be set between 1 to 2 and 1 to 4.

[00:18:25]the initial sensitivity should be set  between negative 1 and negative 2.

[00:18:30]and the initial peep should be set between four  to six centimeters of water pressure the initial ventilator settings are set based on the patient's  condition but must be adjusted as their condition changes for example it's common for a patient to  save an fio2 of 100 percent when they are first intubated and placed on the ventilator however as  the patient's oxygenation status improves the fio2 setting should be decreased Switching gears just  a bit next we need to discuss artificial Airways prior to being connected to the ventilator a  patient must first be intubated as previously mentioned this is the process that involves the  insertion of an artificial Airway into the trachea and the two primary types again are ET tubes  and tracheostomy tubes endotracheal tubes are inserted through the nose or mouth and then pass  through the vocal cords into the trachea where tracheostomy tubes are inserted through a surgical  incision in the neck and directly into the trachea but there are some secondary types of  artificial Airways that may be used in certain situations and I want to briefly mention  them in this video so these include the following Oreo pharyngeal Airways nasopharyngeal Airways and  LMA or laryngeal mask Airway King laryngeal tubes esophageal obturator Airways esophageal gastric  tube Airways esophageal tracheal combat tubes and double Lumen endotracheal tubes each type of  artificial Airway has its own advantages and disadvantages that must be considered when used  during mechanical ventilation but we cover each of these in other videos and articles on this channel  and on our website so definitely check those out if you want to learn more the next topic that we  need to discuss is the drugs used in mechanical ventilation some examples of the most common types  include sedatives analgesics and paralytics the use of drug therapy during mechanical ventilation  is essential to achieve a desired patient outcome that is why respiratory therapists must fully  understand these drugs to avoid complications and prolonged mechanical ventilation sedatives are a  class of drugs used to calm and relax the patient reduce anxiety and maintain the patient ventilator  interaction some examples include benzodiazepines neuroleptics and anesthetic agents analgesic  agents are a class of drugs used to relieve pain and prevent discomfort associated with  mechanical ventilation some examples include morphine Fentanyl and hydromorphone paralysis  can be achieved with neuromuscular blocking agents that are classified as depolarizing and  non-depolarized depending on their mode of action but moving right along now we need to talk  about managing patients on the ventilator ventilator management is the process of operating  a mechanical ventilator and ensuring that it delivers adequate levels of support to the patient  this includes assessing oxygenation ventilation assessing low mechanics adjusting ventilator  settings reviewing the patient's progress managing the ventilator circuit managing the  artificial Airway providing humidification therapy implementing valve prevention strategies providing  nutritional support maintaining fluid and electrolyte balance and documenting the results  the primary goal of mechanical ventilation is to improve the patient's oxygenation and ventilation  while minimizing ventilator-induced lung injuries therefore as previously mentioned it's important  to make adjustments to the ventilator settings depending on the patient's condition and  another part of ventilator management is monitoring mechanically ventilated patients  mechanical ventilation is a type of life support that requires close monitoring of the patient this  includes the process of assessing how the patient is responding to receiving positive pressure  ventilation the parameters that must be monitored when a patient is on the ventilator include  their Vital Signs breast sounds chest Imaging chest movement fluid balance blood gas results  capnography and cerebral perfusion pressure mechanical ventilation monitoring is a job duty  of both respiratory therapists and nurses in the ICU however only respiratory therapists  are responsible for making adjustments to the patient's ventilator settings another important  topic that I need to mention is ventilator alarms ventilator alarms are designed to notify medical  professionals when there is a problem with the patient ventilator interaction there are several  types of insulator alarms that you must know including high pressure low pressure low volume  high frequency apnea High Peep and Low PEEP ventilator alarms can be visual audible or both  depending on the mode settings patient's condition and the type of insulator which leads to the  next topic and that is ventilator waveforms ventilator waveforms are graphical representations  of the patient's breathing pattern that is displayed on the ventilator screen the most  common types of waveforms to assess a patient's ventilation include the flow volume Loop pressure  volume Loop constant flow waveform descending ramp flow waveform pressure time waveform and the  flow time waveform these ventilator graphics and waveforms can be used to assess the patient's  lung mechanics ventilator settings and response to mechanical ventilation and they should also  help with ventilator troubleshooting which is the next topic that we need to discuss there are  several things that can go wrong during mechanical ventilation therefore ventilator troubleshooting  refers to the process of identifying and resolving problems in the patient ventilator interaction  some examples of potential problems that can occur include bronchospasm secretion buildup Airway  obstruction Dynamic hyperinflation a kink in the ET tube a patient biting the ET tube improper  patient positioning drug-induced distress abdominal distension leaks in the circuit  inadequate oxygenation inadequate ventilation improper ventilator settings patient ventilator  asynchrony ventilator alarms that are sounding a technical machine error lung over inflation  Auto peep excessive peep improper waveforms obstructive expiratory valve and apnea that is  due to a disconnection oh yes as you can see a lot can go wrong but again respiratory therapists  must be familiar with common ventilator problems and how to resolve them quickly and efficiently  this involves assessing the situation analyzing the pertinent data and finding a viable solution  which means that you must always remember the primary goal is to protect the patient by ensuring  that they are receiving adequate ventilation and oxygenation therefore if a problem occurs in  the patient ventilator system it may require disconnecting the patient and delivering  breasts with a manual resuscitator until the problem is resolved and the next essential  topic that we need to discuss is ventilator weak weaning from mechanical ventilation is the process  of slowly reducing the level of support that a patient needs in order to eventually be able to  breathe on their own weaning success occurs when a patient is able to tolerate spontaneous breathing  for 48 hours following extubation without the need for re-intubbation there are several factors that  can contribute to weaning success including the type of respiratory disease severity the patient's  age the presence of comorbidities and the length of time on the ventilator as previously mentioned  weaning failure occurs when a patient does not pass a spontaneous breathing trial or if there is  a need for reintubation within 48 Hours of being removed from the ventilator in general the greater  the amount of time a patient is on the ventilator the higher the risk of wing failure therefore  patients with chronic diseases such as COPD are also more likely to experience weaning failure  and you must also be familiar with the weaning criteria when assessing a patient's Readiness to  wean from mechanical ventilation there are some parameters that must be met the first step for  considering weaning requires the resolution of the acute phase of the disease that caused mechanical  ventilation in the first place then the patient must have an adequate cough with manageable  secretions and they must be hemodynamically stable if so then you can proceed to check the other  criteria which include acceptable ABG results frequency tidal volume vital capacity minute  ventilation maximum inspiratory pressure or negative inspiratory Force maximum expiratory  pressure rapid shallow breathing index acceptable oxygenation acceptable PF ratio acceptable  shunting acceptable alveolar to arterial oxygen gradient static compliance Airway resistance Dead  Space to tidal volume ratio and the patient must pass the spontaneous breathing trial and again the  acute condition that initially required mechanical ventilation must be resolved or significantly  improved in order for weaning to be successful and just a reminder a spontaneous breathing trial  is the primary test used to assess a patient's Readiness for weaning from the ventilator it  involves a period of time where limited or no support is provided by the ventilator during which  the patient's Vital Signs and respiratory status are closely monitored the trial is considered  successful if the patient is able to maintain adequate oxygenation and ventilation without any  significant distress if the patient does not meet the required criteria they should be placed back  on the ventilator and given additional time to rest and recover and that leads to the next topic  which is extubation extubation is the process of removing an endotracheal tube from the patient's  trachea and discontinuing mechanical ventilation the decision to perform extubation  is based on the following factors the patient's ability to protect the airway the  ability to maintain adequate respiratory function their ability to manage secretions their ability  to maintain adequate oxygenation their ability to maintain hemodynamic stability and their  ability to cooperate with the medical team if the patient meets the above criteria extubation  would be indicated and the endotracheal tube can be removed this procedure is typically performed  by respiratory therapists and since I've been spending this entire time talking about mechanical  ventilation in adults I feel like I also need to talk about neonatal mechanical ventilation which  is the process of delivering positive pressure to an infant's lungs for breathing support just  like adults this would be indicated when the infant's respiratory efforts are insufficient  to maintain adequate oxygenation and ventilation however mechanical ventilation in newborns  is different than in adults due to obvious anatomical differences for example infants have  much smaller lungs therefore they will require smaller tidal volumes Additionally the pressure  needed to ventilate a neonate's lungs is much lower than in adults these primary differences in  pulmonary mechanics require special considerations when providing mechanical ventilatory support  so as you can see mechanical ventilation is a wide-ranging complex topic however is one that  must be understood by medical professionals especially respiratory therapists and to be honest  this video only scratches the surface of all the information that is required for you to know but  we do have a guide on our website that goes into more detail and breaks it all down in a simplified  way so definitely check that out if you want to learn more I will drop a link to it below this  video down in the description but if you want to support the channel I would greatly appreciate  it if you liked and subscribed and there should be some other helpful videos popping up on your  screen right about now that I think you'll enjoy and just a quick reminder we are not doctors  this video is for informational purposes only thank you so much for watching have a blessed  day and as always breathe easy my friend