Transcript for:
Mechanical Ventilation Lecture Notes

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.   the initial sensitivity should be set  between negative 1 and negative 2.   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