Skip to main content

Mechanical Ventilation

Mechanical Ventilation


Mechanical ventilation is a device that breathes for someone who is unable to breathe for themselves.

Mechanical ventilation is also called positive pressure ventilation. Following an inspiratory trigger , a predetermined mixture of oxygen is forced into the central airways and then flows into the alveoli. 

Mechanical ventilators are set to deliver a constant volume , a constant pressure or a combination of both with each breath. Modes of ventilation that maintain a minimum respiratory rates regardless of whether or not the patient initiates a spontaneous breath are referred to as assist control. Because pressures and volumes are directly linked by the pressure volume curve, any given volume will correspond to a specific pressure, and vice versa, regardless of whether the ventilator is pressure or volume cycled.

Why is it needed ? 

Brain and spinal cord injury or disease : 
An injury or disease to the brain can interfere with the signs that control breathing. Damage to the spinal cord can block the brain's signals from reaching the breathing muscles.

Disorders of the Muscles : 
Can weaken the breathing muscles or change the way in which they receive signals from the brain. This can happens with polio and muscular dystrophy.

Lung Disorders : 
Affect the tissues of the lungs making it difficult for a person to breathe on their own. These disorders include COPD, asthma, chronic bronchitis, emphysema, interstitial , or fibrotic lung disease.

Sleep Disorders : 
Sleep apnea is a condition in which people stop breathing during sleep . These patients may use a form of ventilation only while sleeping called CPAP or BiPAP .

How Does it Work ? 

Mechanical Ventilation is different from how we naturally breathe. During natural inhalation , the diaphragm muscle contracts and the chest expands. This creates a vacuum that pulls air into the lungs. During a natural exhalation, the diaphragm muscle relaxes and air leaves the lungs.

A ventilator works by pushing air into the lungs. The air is pushed in until it reaches a pre set volume or pre set pressure. Once the lungs are full, the vent stops pushing the air into the lungs. This is similar to letting air out of a full balloon.  

Modes of ventilator :

  • Controlled : The ventilator provides the breath when a patient is unable to breath on their own.
  • Supported : The patient is able to breath on their own but needs a little help.The ventilator will provide a small amount of pressure to increase the size of their natural breath.
  • Combination : A combination of controlled and supported breathing that fine tunes the breath.
The ventilator will deliver the breath in 2 different ways :
  1. Volume : The ventilator delivers a pre set volume of air with every breath.
  2. Pressure : The ventilator will deliver a breath until a pre set pressure is reached.
Ventilator and Patient Monitoring :

Patient monitoring and ventilator checks re generally performed every 4 hours in the hospital. This is important to guarantee proper ventilator function and to know if there is a patient issue , such as :
  • The patient needs suctioning
  • The patient needs a breathing treatment
  • The equipment is functioning properly.
Alarms : 
The ventilator is equipped with the safety alarms. An alarm will sound if the ventilator exceeds or drops below certain limits. Always look at and attend to the patient first. Address the alarm situation first.
  • Low pressure alarm : indicates that the pressure in the ventilator circuit has dropped. Low pressure alarm are usually caused by a leak or disconnect.
  • Low Minute Ventilation :  This alarm will sound when the amount of air taken in per minute drops below a set value.  
  • High pressure volume : This will sound when the pressure in the circuit has increased.
Moisture and Humidity : 
It is important to heat and humidify the air delivered from a ventilator. Dry, cold air can damage the delicate tissues of the airways and cause mucus plugs.
Heat and humidity can be delivered in 2 different ways :
  1. HME (Heat Moisture Exchanger) 
  2. Heated Humidifier 

In order to reduce the chance of infection :
  • Wear gloves when touching the ventilator circuit or trach tube.
  • Wash your hands before and after contact with the patient.
  • Wear a mask if the patient has a contagious respiratory diseases or if you are sick and could infect the patient. 
Labels:

Comments

Post a Comment

If you have any doubt. Let me know

Popular posts from this blog

Are We Brainwashed During Sleep?

 In a new study, researchers suggest that tonight while you sleep, something amazing will happen within your brain. Your neurons will go quiet. A few seconds later , blood flow out of your head . Then, a watery liquid called cerebrospinal fluid (CSF) will flow in, washing through your brain in rhythmic, pulsing waves. The study is the first to illustrate that the brain's CSF pulses during sleep,and that these motions are closely tied with brain wave activity and blood flow. The research was conducted by a team from Boston University. Earlier studies have suggested that CSF flow and slow-wave activity both help flush toxic,memory impairing proteins from the brain. As people age, their brains often generate fewer slow waves. In turn, this could affect the blood flow in the brain and reduce the pulsing of CSF during sleep., leading to buildup of toxic proteins and a decline in memory abilities. Although researchers have tended  to evaluate these processes separately, it now appea...
Post a Comment
Read more

PMIS : Latest post Covid-19 challenge for doctors

In a major cause of worry for doctors, several COVID-19 positive children in Mumbai are showing symptoms of a life threatening disorder. So far , two children have died after being diagnosed with the PMIS . What is PMIS ? Paediatric Multisystem Inflammatory Syndrome (PMIS) is a very rare , but serious inflammatory condition that affects the children.  What are the symptoms of PMIS ? Mild symptoms of PMIS include fever, cough, sore throat and a rash. It can also cause swelling of the hands, feet and lymph nodes. In more severe cases, PMIS can also affect blood pressure , the heart and the kidneys. Symptoms of PMIS may not appear until several weeks after the initial infection. In some cases, families may not know their child had COVID-19 until they show symptoms of PMIS. In general , it is important to remember that symptoms of COVID-19 tend to be milder or do not appear as often in children. What causes PMIS ? The cause of PMIS is not known , but doctors think that it is related to...
Post a Comment
Read more

Lockdown induced Painful periods ?

PAINFUL PERIODS IN LOCKDOWN :  Many women have complained of painful and erratic periods in the last three months.The nationwide lockdown resulting from COVID-19 pandemic has affected the menstrual cycles in a mysterious way , bringing unprecendented changes in the flow , duration and pain scale. "Women have faced high-stress levels during lockdown due to uncertainity of life , work , resultant financial crisis, etc. Balancing home and work has also been a problem. Stress hormone 'cortisol' has a direct effect on periods. It can cause  a considerable delay in periods or no periods at all. STress can also raise insulin imbalance in the body which gives way to the secretion of the leptin hormone. This causes cycles to be delayed by 7 to 8 days or more. The reason that women are experiencing painful and erratic periods during the lockdown is sttress, change in sleeping patterns , irregular diet and even excessive exercising. "Cortisol and the hypothalamic pituitary axis ...
Post a Comment
Read more