Better understanding of physiology, anatomy, and disease patterns is triggering a new wave of innovation in ventilation.

Ventilators have evolved from basic machines to complicated, electronic, microprocessing engines. Over the last two decades, ventilator capabilities and options for critical care and anesthesia ventilators have rapidly advanced. These advances in ventilator modalities – in conjunction with a better understanding of patient physiology and the effects of positive pressure ventilation on the body – have revolutionized the mechanical ventilation process. Clinicians today have a vast array of mechanical ventilator mode options designed to match the pulmonary needs of the critically ill and anesthetized patient. Modes of mechanical ventilation continue to be based on one of two variances – volume-based or pressure-based. The wording describing the standard ventilatory modes on select present-day ventilators has changed, yet the basic principles of operation have not changed compared with older ventilators.

Global Market

The global mechanical ventilator market size is expected to reach USD 5.5 billion by 2022. The global market witnessed a significant growth over the past two decades, and it has been characterized by technological innovation and increasing preference for portable and home-care ventilators. Rising geriatric population, growing prevalence of respiratory diseases, and increasing number of preterm births are expected to fuel the growth of this market in the coming years.

Tight budgetary constraints faced by ventilator manufacturers and healthcare service providers are the factors impeding the growth of this market. Technical advancements, such as rapid innovation in the field of positive airway pressure (PAP) devices, portability, and improvement in battery life of transport and portable devices are the primary influencers in the mechanical ventilators market.

Critical care ventilators are expected to account for over 40 percent of the market share by 2022 owing to the technological advancements such as Spontaneous Breathing Trial (SBT) and AutoTrak, and reporting software that influence better care provision are expected to boost market growth further.

Transport and portable ventilators are expected to grow at a lucrative CAGR of over 7 percent over the next 5 years. Hospitals are promoting use of portable ventilators to provide faster and continuous care to patients even prior to their arrival in the premises. Portable ventilators fulfill the need of patients to obtain home care, thereby increasing their popularity.

Manufacturers are focusing majorly on launching new products in order to achieve growth in the ventilator market. They are also focusing on acquiring local and international players to expand their portfolios and enhance their distribution channels in emerging markets. Technological advancement is another key focus area for manufacturers to improve technologies and thus prevent lung injury and reduce the time spent on mechanical ventilation.

The global ventilator market is consolidated at the top with the top five companies accounting for more than half of the global market share. The major players in the market include Philips Healthcare, ResMed Inc., Medtronic plc, Becton, Dickinson and Company, and Getinge Group. Some of the other players in this market are Drger Group, Smiths Group plc, Teleflex Incorporated, Hamilton Medical AG, and GE Healthcare.

Technology Trends

The emergence of next-generation sensors, single chip solutions, and new-generation pneumatic components has impacted the design architectures of ventilators. Ventilating infants and newborn babies make special demands on ventilation technology, which cannot be met partially by equipment designed for adults. Better understanding of physiology, anatomy, and disease patterns is triggering a new wave of innovation in mechanical ventilation. Ventilation techniques, which ensure automatic adaptation of ventilation to the patient, have been developed only recently.

Advances in Weaning. Owing to mechanical ventilation's (MV) potential complications, such as VILI and severe diaphragmatic atrophy, it is imperative that it be discontinued as soon as the patient is capable of sustaining spontaneous breathing. On the other hand, premature extubation may also be problematic, as higher mortality rates have been reported in patients with extubation failure. Consequently, when and how to perform MV weaning is a key question in critically ill patients. The identification of extubation readiness is usually based on clinical judgment, according to the respiratory, neurological, and hemodynamic status. However, this practice remains greatly subjective, while the timing of extubation is challenging. Therefore, efficient processes to safely reduce and remove ventilator support are necessary. Clinical and research efforts have focused on early identification of weaning readiness. Some studies suggest the use of written protocols to assist clinicians in the management of weaning MV, but their usage in clinical practice remains limited for several reasons, providing and following protocols are time consuming, resulting in fluctuation in protocol implementation and compliance; clinical instructions may not be explicit enough, resulting in variable interpretations of the protocol; and protocols are generally specific to one organization, leading to a certain heterogeneity in clinical practice, being major ones. The development of the closed-loop system (CLS) (computerized protocol implementing its recommendations without caregiver intervention) has resolved some of these issues. While optimizing ventilatory support on a continuous basis according to the patient's respiratory condition, CLS offers consistent orders that constrain interpretation variations among caregivers, potentially resulting in a more efficient application of protocols. The use of CLS leads to a quicker adjustment of ventilator settings assessed by a reduction of time between the assessment of patient status and medical order, and medical order and clinical execution.

Advances in NIV. Noninvasive ventilation (NIV) is defined as the delivery of MV without an endotracheal tube or tracheostomy. NIV comprises both CPAP and bilevel positive airway pressure (BiPAP) ventilation. NIV is increasingly used in pediatric intensive care units (PICUs). In the last decade, the potential indications for NIV in critically ill patients have grown considerably, and the performance of this mode of support has greatly improved. In children developing acute respiratory distress syndrome (ARDS), NIV can be considered as a first line of treatment in milder disease. Despite the lack of clear guidelines, this mode of support definitely has its place in the treatment of a wide range of pathologies in children, including pneumonia, upper airway obstruction, post-extubation respiratory failure, acute chest syndrome, and asthma.

The use of NIV has recently evolved because of the emergence of high-flow nasal cannula (HFNC). This modality is now available from a number of manufacturers and has been widely adopted in pediatric practice. Different mechanisms have been hypothesized to account for the clinical benefits, including washout of the nasopharyngeal dead space, reduction of work of breathing, decrease in airway resistance, and improvement of pulmonary compliance. HFNC has been able to provide a mean pharyngeal pressure of 4 cmH2O when used at a flow of 2 L/kg/minute, but this effect is variable. In clinical use, HFNC allows improvement of comfort and tolerance to NIV and reduction of air leak, gastric distension, and skin injuries, especially in younger children. The role of HFNC outside the PICU still needs to be investigated. It is believed that within a few years, the role of HFNC will be better defined and potentially widened.

To improve NIV success, the achievement of an adequate patient-ventilator synchrony is crucial. Although the performance of ventilators has improved in the last few years, patient-ventilator asynchrony in NIV remains a significant issue. As with invasive ventilation, tools to improve patient-ventilator synchrony during NIV have been recently investigated. Electrical activity of diaphragm monitoring and noninvasive NAVA are feasible and well tolerated in PICU patients with patient-ventilator synchrony improvement. Monitoring esogastric pressure offers another way to improve patient-ventilator interaction during NIV.

Way Forward

The challenge for future research in the area of ventilator technology is to generate controlled clinical studies to support its application. With the impact of financial constraints on healthcare, research will also need to examine the economic issues related to the application of newer modes of mechanical ventilation. Integrating vital signs monitoring with ventilation in conjunction with other assessment parameters may prove to be useful tools to measure the impact of interventions such as suctioning, positioning, muscle reconditioning, weaning techniques, and comfort measures on mechanically ventilated patients.

Prof (Dr) RK Bhattacharyya,Professor Anesthesiology, Assam Medical College, Dibrugarh
Second Opinion
Mechanical Ventilation

Mechanical ventilation is a commonly used technique in the intensive care unit (ICU). Newer modes of ventilation are continually incorporated into daily practice; however, it is most often the case that these new methods do not have any associated studiesdemonstrating advantages over older methods, especially in terms of morbidity or mortality. In most cases, we are only able to find studies that assessed the effects of different ventilator modes on physiological variables.

There appears to be an incongruity between the amount of resources used in the development and introduction of new modes of ventilation and the paucity of information that exists regarding the use and outcomes of mechanical ventilation as well as the description of what modes or settings should be considered standard or conventional mechanical ventilation.

In 1993, a Mechanical Ventilation Consensus Conference analyzed the benefits and complications associated with mechanical ventilation, focusing on the management of patients with acute respiratory failure (ARF).

Reason for Initiation of Mechanical Ventilation

Pathophysiological indications (hypoxemic respiratory failure or hypercapnic respiratory failure) for mechanical ventilation are well known but there are fewer reports about the diseases that cause the respiratory distress.

Management of Mechanical Ventilation

Airway management. The decision to place an oral or nasal tracheal tube rests with the practitioner and is based on a variety of considerations. The major reasons for placing nasal tubes include improved patient comfort, better oral hygiene, and perhaps a decreased risk of laryngeal injury and self-extubation.

Modes of ventilation. Control modes are VC, PC, PRVC, Assist Control, SIMV VC + PS, SIMV PC + PS, SIMV PRVC + PC are commonly used modes of mechanical ventilation. Intermittent mandatory ventilation (IMV), tidal volumes, PEEP, PRVC with pressure support are integrated to support ventilation.

Modern day ICU practice ventilators are mandatory. So many companies bring out ventilators to the market with high standards. Maquet, PB, Draeger, GE, and Hamilton are manufacturing modern equipment along with ventilators.

Prof (Dr) RK Bhattacharyya,
Professor Anesthesiology,
Assam Medical College, Dibrugarh

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