A ventilator is a machine that provides mechanical ventilation by moving breathable air into and out of the lungs, to deliver breaths to a patient who is physically unable to breathe, or breathing insufficiently. Modern ventilators are computerized microprocessor-controlled machines, but patients can also be ventilated with a simple, hand-operated bag valve mask. Ventilators are chiefly used in intensive-care medicine, home care, and emergency medicine and in anesthesiology.
Mechanical ventilation, assisted ventilation or intermittent mandatory ventilation (IMV), is the medical term for artificial ventilation where mechanical means are used to assist or replace spontaneous breathing. This may involve a machine called a ventilator, or the breathing may be assisted manually by a suitably qualified professional, such as an anesthesiologist, registered nurse (RN), paramedic or other first responder, or in some parts of the United States, by a respiratory therapist (RT), by compressing a bag valve mask device.
Tidal volume is the lung volume representing the normal volume of air displaced between normal inhalation and exhalation when extra effort is not applied. In a healthy, young human adult, tidal volume is approximately 500 ml per inspiration or 7 ml/kg of body mass.
An iron lung, also known as a tank ventilator or Drinker tank, is a type of negative pressure ventilator (NPV); a mechanical respirator which encloses most of a person's body, and varies the air pressure in the enclosed space, to stimulate breathing. It assists breathing when muscle control is lost, or the work of breathing exceeds the person's ability. Need for this treatment may result from diseases including polio and botulism and certain poisons.
Barotrauma is physical damage to body tissues caused by a difference in pressure between a gas space inside, or in contact with, the body, and the surrounding gas or fluid. The initial damage is usually due to over-stretching the tissues in tension or shear, either directly by expansion of the gas in the closed space or by pressure difference hydrostatically transmitted through the tissue. Tissue rupture may be complicated by the introduction of gas into the local tissue or circulation through the initial trauma site, which can cause blockage of circulation at distant sites or interfere with normal function of an organ by its presence.
Liquid breathing is a form of respiration in which a normally air-breathing organism breathes an oxygen-rich liquid, rather than breathing air.
Artificial ventilation is a means of assisting or stimulating respiration, a metabolic process referring to the overall exchange of gases in the body by pulmonary ventilation, external respiration, and internal respiration. It may take the form of manually providing air for a person who is not breathing or is not making sufficient respiratory effort, or it may be mechanical ventilation involving the use of a mechanical ventilator to move air in and out of the lungs when an individual is unable to breathe on their own, for example during surgery with general anesthesia or when an individual is in a coma or trauma.
A bag valve mask (BVM), sometimes known by the proprietary name Ambu bag or generically as a manual resuscitator or "self-inflating bag", is a hand-held device commonly used to provide positive pressure ventilation to patients who are not breathing or not breathing adequately. The device is a required part of resuscitation kits for trained professionals in out-of-hospital settings (such as ambulance crews) and is also frequently used in hospitals as part of standard equipment found on a crash cart, in emergency rooms or other critical care settings. Underscoring the frequency and prominence of BVM use in the United States, the American Heart Association (AHA) Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiac Care recommend that "all healthcare providers should be familiar with the use of the bag-mask device." Manual resuscitators are also used within the hospital for temporary ventilation of patients dependent on mechanical ventilators when the mechanical ventilator needs to be examined for possible malfunction or when ventilator-dependent patients are transported within the hospital. Two principal types of manual resuscitators exist; one version is self-filling with air, although additional oxygen (O2) can be added but is not necessary for the device to function. The other principal type of manual resuscitator (flow-inflation) is heavily used in non-emergency applications in the operating room to ventilate patients during anesthesia induction and recovery.
Positive end-expiratory pressure (PEEP) is the pressure in the lungs above atmospheric pressure that exists at the end of expiration. The two types of PEEP are extrinsic PEEP and intrinsic PEEP. Pressure that is applied or increased during an inspiration is termed pressure support.
High-frequency ventilation is a type of mechanical ventilation which utilizes a respiratory rate greater than four times the normal value. and very small tidal volumes. High frequency ventilation is thought to reduce ventilator-associated lung injury (VALI), especially in the context of ARDS and acute lung injury. This is commonly referred to as lung protective ventilation. There are different types of high-frequency ventilation. Each type has its own unique advantages and disadvantages. The types of HFV are characterized by the delivery system and the type of exhalation phase.
Ventilator-associated lung injury (VALI) is an acute lung injury that develops during mechanical ventilation and is termed ventilator-induced lung injury (VILI) if it can be proven that the mechanical ventilation caused the acute lung injury. In contrast, ventilator-associated lung injury (VALI) exists if the cause cannot be proven. VALI is the appropriate term in most situations because it is virtually impossible to prove what actually caused the lung injury in the hospital.
A liquid ventilator is similar to a medical ventilator except that it should be able to ensure reliable total liquid ventilation with a breatheable liquid ·. Liquid ventilators are prototypes that may have been used for animal experimentations but experts recommend continued development of a liquid ventilator toward clinical applications.
Modes of mechanical ventilation are one of the most important aspects of the usage of mechanical ventilation. The mode refers to the method of inspiratory support. In general, mode selection is based on clinician familiarity and institutional preferences, since there is a paucity of evidence indicating that the mode affects clinical outcome. The most frequently used forms of volume-limited mechanical ventilation are intermittent mandatory ventilation (IMV) and continuous mandatory ventilation (CMV). There have been substantial changes in the nomenclature of mechanical ventilation over the years, but more recently it has become standardized by many respirology and pulmonology groups. Writing a mode is most proper in all capital letters with a dash between the control variable and the strategy.
Continuous mandatory ventilation (CMV) is a mode of mechanical ventilation in which breaths are delivered based on set variables. Still used in the operating room, in previous nomenclature CMV referred to "controlled mechanical ventilation", a mode of ventilation characterized by a ventilator that makes no effort to sense patient breathing effort. In continuous mandatory ventilation, the ventilator can be triggered either by the patient or mechanically by the ventilator. The ventilator is set to deliver a breath according to parameters selected by the operator. "Controlled mechanical ventilation" is an outdated expansion for "CMV"; "continuous mandatory ventilation" is now accepted standard nomenclature of mechanical ventilation. CMV today can assist or control dynamically, depending on transient presence or absence of spontaneous breathing effort. Thus, today's CMV would have been called ACV in older nomenclature, and the original form of CMV is a thing of the past. But despite continual technological improvement over the past half century, CMV sometimes may still be uncomfortable for the patient.
Mechanical power is a medical term which is a measure of the amount of energy imparted to a patient by a mechanical ventilator.
A negative pressure ventilator (NPV) is a type of mechanical ventilator that stimulates an ill person's breathing by periodically applying negative air pressure to their body to expand and contract the chest cavity.
Rheotrauma is a medical term for the harm caused to a patient's lungs by high gas flows as delivered by mechanical ventilation. Although mechanical ventilation may prevent death of a patient from the hypoxia or hypercarbia which may be caused by respiratory failure, it can also be damaging to the lungs, leading to ventilator-associated lung injury. Rheotrauma is one of the ways in which mechanical ventilation may do this, alongside volutrauma, barotrauma, atelectotrauma and biotrauma. Attempts have been made to combine all of the mechanical forces caused by the ventilator on the patient's lungs in an all encompassing term: mechanical power.
Atelectotrauma, atelectrauma, cyclic atelectasis or repeated alveolar collapse and expansion (RACE) are medical terms for the damage caused to the lung by mechanical ventilation under certain conditions. When parts of the lung collapse at the end of expiration, due to a combination of a diseased lung state and a low functional residual capacity, then reopen again on inspiration, this repeated collapsing and reopening causes shear stress which has a damaging effect on the alveolus. Clinicians attempt to reduce atelectotrauma by ensuring adequate positive end-expiratory pressure (PEEP) to maintain the alveoli open in expiration. This is known as open lung ventilation. High frequency oscillatory ventilation (HFOV) with its use of 'super CPAP' is especially effective in preventing atelectotrauma since it maintains a very high mean airway pressure (MAP), equivalent to a very high PEEP. Atelectotrauma is one of several means by which mechanical ventilation may damage the lungs leading to ventilator-associated lung injury. The other means are volutrauma, barotrauma, rheotrauma and biotrauma. Attempts have been made to combine these factors in an all encompassing term: mechanical power.
AgVa Ventilator is a mechanical ventilator developed in collaboration with Indian scientist Diwakar Vaish of A-SET Robotics and Dr. Deepak Agrawal, professor of Neurosurgery at All India Institute of Medical Sciences, Delhi. AgVa is designed to be a cost effective and compact ventilator with the ability to push Oxygen as well as atmospheric air, it also has the ability to control ventilator parameters through an Android application.
Proning or prone positioning is the placement of patients into a prone position so that they are lying on their stomach. This is used in the treatment of patients in intensive care with acute respiratory distress syndrome (ARDS). It has been especially tried and studied for patients on ventilators but, during the COVID-19 pandemic, it is being used for patients with oxygen masks and CPAP as an alternative to ventilation.
