Hospital Ventilator Settings – Step by Step
In order to fully learn and understand the concepts of mechanical ventilation, you must first develop an understanding of the ventilator settings.
What is Ventilator Settings?
Ventilator settings are the inputs on a ventilator machine that determine how much support is provided for the patient.
In this post, we’re going to walk you through all the basic ventilator settings that you must know as a medical professional, and be sure to stick around until the end because we’re also going to teach you. Before we go any further just know that I am not a doctor this video is for information on educational purposes only please speak with your physician for medical advice and treatment for yourself and for your patients so now that we got that out of the way.
How to select the appropriate initial ventilator settings? what are ventilator settings to give a brief definition?
Ventilator settings are the controls on a mechanical ventilator that can be set or adjusted in order to determine the amount of support that is delivered to the patient, support can be provided in the form of ventilation and oxygenation you must develop an understanding of
How each setting can be adjusted in order to provide more or less of each type of support for the patient?
Some examples of the basic ventilator settings include
- Ventilator mode
- Title volume
- The frequency
- Rate FIO2
- Inspiratory flow rate
- Ie ratio
- And ventilator alarms
So if you’re ready let’s go through each of these settings one by one so that you can truly learn how the machine operates and provides support for the patient.
First, we have the ventilator mode
Essentially a ventilator mode is a way of describing how the mechanical ventilator assists a patient with inspiration, the characteristics of a particular mode control how the ventilator functions, the mode acts kinda like a brain for the ventilator because it tells it how to perform and operate.
Some of the common modes that you need to know about include
- Assist control
- Pressure support ventilation
- Volume support
- Control mode ventilation
- Airway pressure release ventilation
- Mandatory minute ventilation
- Inverse ratio ventilation
- High-frequency oscillatory ventilation
When selecting a ventilator mode you must first determine if the patient needs full or partial ventilatory support, assist control can be provided if the patient needs full ventilatory support or if they only need partial support then SIMV would be recommended we actually have a full guide and POST on this topic that goes much deeper into all the different modes of mechanical ventilation. ( First Read this Full Article then Read that one )
- let’s talk about the Tidal volume setting – Tidal volume refers to the volume of air that is inhaled and exhaled from the lungs during normal breathing, the tidal volume setting on the ventilator determines how much air is delivered to the lungs by the machine.
- If a patient is in a volume-controlled mode the delivered tidal volume can be adjusted by increasing or decreasing the tidal volume setting on the other hand
- If the patient is in a pressure control mode the delivery tidal volume can be adjusted by increasing or decreasing the pressure setting
- Next, let’s talk about the frequency – which is just the technical term for respiratory rate or it can even be referred to as the breathing rate because this setting simply controls the rate at which breathing occurs it typically refers to the number of breaths that are taken per minute and the normal range is 10 to 20 breaths per minute So simply put the frequency setting on the ventilator determines –
How many breaths are delivered to the patient per minute by the machine
FIO2 or Fraction of inspired oxygen – this refers to the concentration of oxygen that is being inhaled by the patient for patients with severe hypoxemia a fio2 of 100% may be required when mechanical ventilation is initiated but your goal as a respiratory therapist should be to wean the FIO2 down to the lowest possible level that still provides adequate oxygenation.
If a patient receives a fio2 of greater than 60 for a prolonged period of time it increases their chances of oxygen toxicity so that is just something to keep in mind
The flow rate – which refers to the inspiratory flow rate, this setting controls how fast a tidal volume is delivered to the patient by the ventilator this setting can be adjusted relying on the patient’s inspiratory demands, the everyday inspiratory float rate should be set at round 60 liters per minute with that stated most ventilators can supply up to a hundred and twenty liters per minute if a affected person wants a prolonged expiratory time, this is necessary when obstructive diseases are present when it comes to flow rate one thing to remember is that if it’s set too low it could result in patient-ventilator dyssynchrony and an increased work breathing if the flow rate is set too high it could result in decreased mean airway pressures
The I:E ratio Or inspiratory to expiratory ratio – It refers to a ratio of the inspiratory portion compared to the expiratory portion of the breathing cycle for patients on the ventilator the normal ie ratio is between one to two and one to four a larger ie ratio may be delivered if a patient is in need of a longer expiratory time due to the possibility of air trapping.
If you’re needing to adjust the patient’s ie ratio you can do so by making changes to
- The flow rate
- Inspiratory time
- Expiratory time
- Title volume
- The frequency
The sensitivity – also known as the trigger the sensitivity control is what determines how much effort the patient must generate in order to trigger a breath from the machine and when I say effort what I’m really referring to is how much negative pressure the patient must generate for the ventilator to deliver a breath.
The normal sensitivity setting should be set between negative 1 and negative 2 centimeters of water pressure
If the sensitivity is set too high it will cause the ventilator to initiate auto triggering and increase the total frequency of breaths if it’s set too low The patient could have a difficult time initiating a breath, to begin with so this is definitely something that all of my respiratory therapy students should remember especially those who are preparing for the TMC EXAM.
Whenever you see a question about a patient who is struggling to initiate a breath just remember that you likely need to adjust the sensitivity setting
let’s talk about PEEP or positive and expiratory pressure – peep is essentially an amount of positive pressure that is delivered during the expiratory phase of the breathing cycle it helps prevent the closure of alveoli in the lungs which allows an increased amount of time for oxygen exchange to occur this is why peep is often recommended for patients with oxygenation issues in fact the most common indication for peep is in patients with refractory hypoxemia and those who have not responded well to a high fio2 setting
So let’s say you have a patient who is struggling with hypoxemia
Their pao2 and spo2 levels just aren’t quite where we need them to be the first thing you could do is to try to increase the fio2 setting you can increase the fio2 up to 60% to see if it fixes the issue if not and if the patient is still showing signs of hypoxemia this is when you would want to initiate beep.
Ventilator Alarms – A ventilator alarm is a safety mechanism on the machine that uses set parameters to provide alerts whenever there is a potential problem related to the patient-ventilator interaction.
Some of the common ventilator alarms include
- High pressure
- Low pressure
- Low expired volume
- High frequency
- High peep
- Low peep
Of course, there are different causes for each of the different alarms we’re not going to cover them all in this POST but we do have a guide on our website that goes into much more detail.
How to set up a new patient on the ventilator?
That is why we must talk about the initial ventilator settings but real quick, Once it has been determined that mechanical ventilation is indicated for a patient who needs help with oxygenation and or ventilation then you must know.
How to properly input the initial ventilator settings?
Keep in mind that each mechanical ventilator machine is different So be sure to abide by the guidelines provided by the manufacturer of that machine However here are some of the general guidelines that you can use when determining the initial ventilator settings for a new patient.
- First, you will need to select the Mode and it’s important to remember that any operational mode will work when setting up the initial ventilator settings you should not get too caught up deciding on the right mode and this is especially true when we’re talking about the questions that you will see on the TMC EXAM but with that said just as a reminder.
- You can select Assist control if the patient needs full ventilatory support or
- SIMV – if they only need partial support.
- The initial tidal volume setting should be 5 to 10 milliliters per kilogram of the patient’s ideal body weight – so if a patient weighs 70 kilograms their initial tidal volume setting should be between 350 to 700 milliliters.
- Now I realized that many of you guys were probably taught to use six to eight as the range for the initial title volume now yes that one technically is correct as well and it’s even more precise than the 5 to 10 range but through my experience using 5 to 10 will still help you come up with the correct answer and it makes the calculation much easier because you can quickly do it in your head but like i said it’s up to you you can use whichever one you feel more comfortable with.
- So moving right along the initial frequency setting – should be between 10 to 20 breaths per minute.
- The initial fio2 setting should be 30- 60 % unless the patient was previously receiving a higher percentage of oxygen before intubation.
- So if that’s the case then you would simply use the previous FIO2 that they were already on but in general, you should strive to provide the lowest concentration of oxygen that’s possible to maintain a normal POA2 and FIO2 up to 100% as an initial setting is appropriate for patients with severe oxygenation issues, just keep in mind that you’ll want to try to titrate and wean them down below 60 as soon as possible.
- Flow rate – The initial flow setting should be between 40 to 60 liters per minute.
- The initial I:E ratio setting should be between one to two and one to four.
- The initial sensitivity setting should be between a negative one and negative two centimeters of water pressure.
- The initial peep setting should be set at four to six centimeters of water pressure.
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