Medical Ventilators Ryan Sanford Daniel Tajik
Medical Ventilators Assist patients that have trouble breathing on their own. 2
Oxygen Intake The Respiratory System has the responsibility of providing the body with oxygen. Oxygen enables aerobic respiration in the cells. Our heart will circulate the oxygenated blood throughout the body. 3
Breathing Inhaling and exhaling requires the increase and decrease in lung volumes. 4
Components of Air Inhaling Exhaling Oxygen 21% 13.6% Nitrogen 78% 78% Carbon Dioxide 0.04% 4% Other Gas 0.1% 1% Only 35% of the oxygen that we inhale is actually used for aerobic processes. 5
Medical Ventilation Negative Pressure Ventilation Create a negative pressure gradient inside the lungs relative to the atmosphere. Positive Pressure Ventilation Lungs have positive pressure relative to the atmosphere. Air will have to be forced into the lungs 6
Iron Lung First negative pressure ventilator. Consists of pressurized chamber that will expand lungs and create low pressure system. 7
Biphasic Cuirass Ventilation 8
Biphasic Cuirass Ventilator Consists of a pressurized chamber that will pressurize and depressurize. By doing so lungs will expand and contract. Respiratory rates, inspiratory and expiratory volumes can be adjusted. 9
Biphasic Cuirass Ventilation Used in many applications such as in Spinal Muscular Atrophy, Neuromuscular Failure, CNS injuries, Asthma and as a life saving device. Also used when positive pressure ventilation fails. 10
Biphasic Cuirass Ventilator Consists of 3 modes Control Mode Ventilator has full control over patient Respiratory Triggered Assisted breathing. As soon as patient begins to breath ventilator will kick in. Respiratory Synchronized Spontaneous breathing. Will assist patients in attaining healthy amount of oxygen. 11
Biphasic Cuirass Ventilator Advantages Increased Quantity of Life Mimics normal breathing Max carbon dioxide output Disadvantages Decreased Quality of Life Obese patients unable to fit cuirass over chest. Trachea must not be obstructed 12
Methods Of Respiratory Ventilation There are other types of ventilators that vary in terms of their method of providing oxygen Most modern day ventilators use positive pressure ventilation, which means to exert the pressure directly onto the lungs. 13
Pressure Ventilators The machine measures the pressure exerted, and will switch directions when the limits of the pressure are reached. These limits are set by a technician who determines the ideal tidal volume beforehand for the patient 14
Pressure Ventilators This ventilator is very commonly used in patients with acute lung injuries, as well as young children. Very commonly used with people suffering from injuries which may have breaches in the lung. Figure 1: Graph displaying the oxygen output when using a pressure ventilator. Note how the rhythm of breathing remains the same Since these ventilators continue to apply more oxygen until the pressure limit is reached, enough oxygen will always be supplied. 15
Pressure Ventilators PVs are also used in spontaneous breathing, or assisting a patient with their breathing As a patient varies their inhalation, the machine will apply more/less volume to reach the limiting pressures. One issue with PVs is that they require a large amount of input information (tidal volume) before operation P=V t / C r + (V t / T i )R R + PEEP total 16
Pressure Ventilators Another issue with PVs is that they require more observation from the operator This is due to the fact that a rapid change in the lungs ability expand may lead to hyperventilation and hypoxia Severe lack of oxygen to the hand 17
Volume Controlled Ventilators Volume Controlled Ventilators (VV) rely on applying the same volume for each breath, with varying applied pressure 18
Volume Controlled Ventilators VV s function by repeatedly pumping a specific volume of air into a patients lungs. Minute ventilation can be specified beforehand, producing constant oxygen flow Commonly used in surgeries where chest/lungs resist expansion 19
Volume controlled Ventilators VV s are also commonly used during emergency transport, when calculating tidal volumes becomes difficult. 20
Volume Controlled Ventilator One issue with VV s is that they operate differently than people. Where humans depend on rate of inhalation, VV s depend on volume. This means that this machine cannot properly be used to assist breathing, only provide mandatory breathing 21
But how do we decide between two ventilators? 22
Variety of Ventilators Each patient will require a different kind of ventilator depending on their condition. In some cases, a hybrid ventilator known as a Dual Controlled Ventilator can be used, where the device alternates between volume and pressure depending on the condition of the patient 23
Variety of Ventilators Airway pressure release ventilation Continuous mandatory ventilation Intermittent mandatory ventilation Mandatory minute ventilation Pressure regulated volume control Adaptive support ventilation Continuous positive airway pressure Bilevel positive airway pressure High-frequency ventilation (Active) High-frequency ventilation (Passive) Here are just a few of the possible ventilators that can be used in different scenarios 24
Types of Ventilator Assistance There are three type of ventilator assistance 1. Spontaneous: Breathing is regular from the patient 2. Assisted: Breathing is not rythmic, machine assists the patient 3. Mandatory: No breathing from patient, machine has full control of rhythm,depth 25
Variance in Patients Since a traumatized patient is expected to cycle between modes, a hybrid machine was developed. The patient will be treated as a mandatory breathing victim, but at patient inhalation, the machine switches to spontaneous/assisted to allow them to maintain control 26
Thanks! Final Test Question: A person performing CPR on an unconscious non-breathing victim would be what kind of ventilator? 1. Spontaneous Volume Controlled Ventilator 2. Mandatory Pressure Controlled Ventilator 3. Mandatory Volume Controlled Ventilator 4. Assisted Pressure Controlled Ventilator 5. Spontaneous Pressure Controlled Ventilator 27
Reference Geddes, A. (Nov.-Dec. 2007) The History of Artificial Respiration. IEEE Engineering in Medicine and Biology Society Breathing and Hayek RTX. (2008) United Hayek Medical. http://www.unitedhayek.com/patients Biphasic Cuirass Ventilator, (2008) United Hayek Medical. http://www.unitedhayek.com/bcv Bush. A, Lincoln. C, Petros. A, Redington. A, Shekerdmian. L, Shore, D. (1997) Cardiopulmonary interactions in healthy children and children after simple cardiac surgery: the effects of positive and negative pressure ventilation. http://www.ncbi.nlm.nih.gov/pmc/articles/pmc1892328/ Broccard. A, Marini. J. (2010) Basics of Mechanical Ventilation. University of Minnesota. http://www.slideshare.net/fergua/basic-mechanical-ventilation 28
Reference Neligan, P. Pressure Controlled Ventilators. University of Pennsylvania. http://www.ccmtutorials.com/rs/mv/page10.htm Neligan, P. Volume Controlled Ventilators. University of Pennsylvania. http://www.ccmtutorials.com/rs/mv/page5.htm 29