Technological advances in microprocessor-controlled ventilation integrated with the complexity of new ventilator modes have further improved the care of the critically ill patients.
Mechanical ventilation continues to be an evolving modality in the critical care environment. The rising prevalence of respiratory diseases, increasing incidence of preterm births, urbanization and growing pollution levels, high prevalence of tobacco smoking, rapid growth in the geriatric population, and rising number of ICU beds are the major factors driving the need of ventilation in the modern world. According to a report from MarketsandMarkets, the global ventilator market is projected to surge from its current USD 859.9 million valuation to USD 1.261 billion by 2023, growing at a compound annual growth rate (CAGR) of 8 percent.
Technological advances in microprocessor-controlled ventilation integrated with the complexity of new ventilator modes have provided the multidisciplinary team opportunities to further improve the care of the critically ill ventilator patients. Advanced ventilators are also primed for any and all kinds of exigencies and have a lot of checks and balances in place. Patient-specific parameters such as pressure of air, volume of air, flow speed, and general parameters such as air leakage, mechanical failure, power failure, battery backups, oxygen tanks, and a remote control are all equipped with sensors and monitors. This is meant to make sure that the patient does not lose those precious few breaths which could even cost a life.
The modern ventilator traces its history to technology which started almost in the late 1600s, when an English scientist, John Mayow came up with the idea of external negative pressure ventilation. The relentless hard work of both doctors and engineers, from the early days of the 20th century has led to leaps in the technology of ventilators and resulted in advanced and computer-controlled life savers that we have come to depend upon today.
Portable devices. New portable life support ventilators are lighter and smaller providing invasive, noninvasive, and mouthpiece ventilation. Designed to work in hospital, institutional, transport, and home environments, they deliver a comprehensive set of ventilation modes and settings to meet patient needs. The advanced ventilation technology combines responsive leak and circuit compensation as well as precision flow trigger controls to enable comfortable breathing and accurate therapy.
Hybrid respiratory solutions. Since the iron lung, respiratory equipment has limited the mobility of ventilator patients. However, recent portable devices may combine various respiratory therapies such as ventilation, oxygen, cough, suction, and nebulization. The devices are controlled through an intuitive touchscreen interface and user-friendly operating system. Caregivers can seamlessly switch between therapies with the touch of a button and no longer need to change the patient circuit between therapies.
Alarm fatigue reduction. Alarm fatigue continues to be a major healthcare concern, ranking third on the ECRI Institute’s top 10 health technology hazards for 2017. Mechanical ventilators are often one of the major sources of an alarm and several manufacturers have developed technology to reduce the incidence of nonactionable alarms. Ease of use within the context of alarm management is a key to patient safety. While ventilators have default alarm settings, the ability to customize those settings is important. Modern devices have an intuitive and simple touch, turn, and confirm interface to allow the user to change parameters. Users can customize settings to suit the needs of the individual patient.
Wireless connectivity. Recently, manufacturers are developing wirelessly connected portable ventilators to have a meaningful impact on patient outcomes. Connecting to cloud-based patient management application, the current bluetooth-enabled devices turn medical-grade data into actionable information, delivering it directly to mobile devices or desktops of care providers multiple times per day. This solution enables care teams to monitor patients remotely and proactively, allowing for fast and informed clinical decisions including early intervention, which can help avoid unnecessary readmissions and lower cost of care.
Diaphragm pacing machine. This revolutionary technology may soon allow hundreds of patients on mechanical ventilation, including young children and those injured in road accidents, to have lives that are more fulfilling. Currently available systems involve an external transmitter and an implanted receiver, but fully implantable diaphragmatic pacing systems are being developed. The current pacing systems are more affordable and easier to place than the earlier systems.
Computational tools. The rationale of intelligent ventilators is to improve patient management by analyzing and integrating information coming from large number of sources, and guaranteeing continuous adjustment of the ventilation even when expert personnel are not constantly available, improving patients’ treatment, and minimizing clinical errors. Engineering science has developed several computational tools that start from a set of input (measured) variables and can determine the desired outputs (settings) that can be used to model the cardiorespiratory system and/or the decisional process of the clinicians to automatically identify an optimal ventilation strategy.
Turbine-based ventilator. Technological limitations in old-generation turbines like lower peak flows which cause air hunger, few ventilation modes, high noise level of turbine, bulky design, and high cost of turbine maintenance made hospitals prefer conventional ventilators over turbine-based ones in earlier few years. These challenges as well as the goal to satisfy latest stringent ICU requirements have created the foundation of revolutionary changes in turbine technology. New-generation turbines are compact in size with low noise level and high-peak flows to guarantee uncompromised ventilation to meet flow demand on breath onset during spontaneous ventilation.
To cover the gap from conventional turbine ventilators to versatile ICU ventilators, many enhancements have been done in areas of lung protective strategies by integrating specific modes like airway pressure release ventilation (APRV) and pressure regulated volume control SIMV (PRVC-SIMV) in conjunction with special maneuvers such as PV tool, occlusion pressure, negative inspiratory force, intrinsic PEEP, etc. In addition, synchrony tools and leak compensation ensures an outstanding noninvasive ventilation performance. To address the cross-contamination issue from infectious patients, leading manufacturers improvise the design further by developing detachable and steam-sterilizable inspiratory, expiratory valves, and flow sensors.
The Road Ahead
To go further, mainly two kinds of advancements are required to provide best quality of care. First being the development of cost-effective, accurate, miniaturized, and reliable sensors to measure patient variables (e.g., pressure, flow, and oxygenation) and actuators to build machines reliably providing the desired pressure/flow to patients (e.g., blowers and valves). The second is the application of mathematical models, control systems, and artificial intelligence to tailor the action of the mechanical ventilator to each patient’s needs. These challenging tasks must be carried out by a truly interdisciplinary approach, joining the knowledge and expertise of bioengineers and physicians.
While many manufacturers are concentrating on connectivity, compatibility with hospital’s existing information systems (HIS) is a challenge along with its overall cost. Moreover, patients’ needs are also changing with time owing to the evolution of both pathology severity and treatments. Therefore, an optimal ventilation strategy could improve outcomes and comfort, reduce adverse events, and avoid prolonging ventilation, with its associated risks and costs. To reach these goals, interdisciplinary efforts are more and more necessary as the complexity of modern mechanical ventilators increases in terms of integrating and controlling a variety of input and output variables for further improving patients’ treatment.
Current Trends in Mechanical Ventilation
Even though the concept of mechanical ventilation dates back to the 14th century with Vesalius, it is only in the last century that it has been widely introduced in routine clinical practice. This was the result of combining the advances in our understanding of respiratory physiology, pathophysiology, and clinical management of patients together with technological progress in mechanical, electronic, and biomedical engineering. From the early 1970s, ventilators benefited from the progresses in electronics and started incorporating more advanced monitoring of flow and pressure variables. Improvements in monitoring also allowed the possibility of using real time variables to control the action of the machine, opening the development of assisted mechanical ventilation as a way to manage the weaning of patients from periods of volume-controlled ventilation.
Among the many newer innovations the Servo targeting ventilator modes are the current trend in targeting schemes for mechanical ventilators. Automatic tube compensation, neutrally adjusted ventilator assist (NAVA), proportional assist ventilation (PAV), and PAV-plus are examples of this category. They allow high degree of synchrony with patients and support the work of breathing, assigning to the patient’s neural respiratory control the definition of the ventilator waveform. The next process of change involved the adaptive targeting which allows the ventilator to automatically set one ventilation variable to maintain another ventilation variable at a predefined value.
Even if these physiopathology concepts are now well-understood, the key variables needed to tailor ventilation are not yet measurable at the bedside, leading to a significant gap between what we know about an ideal ventilation strategy and what can be applied in clinical medicine. The future outlook is to incorporate technologies for assessing physiological variables at the bedside and to incorporate them into mechanical ventilators with enhanced monitoring capabilities. It will provide the clinicians with the information needed to properly tailor mechanical ventilation.
Several systems have been described in literature for setting ventilation parameters based on some form of artificial intelligence. Therefore, an optimal ventilation strategy is an adaptive process aiming to treat the acute condition and support the gradual weaning from the ventilator or adjust to the natural fluctuations of chronic disorders. To reach the goals, advancement of our understanding in pathophysiology, medicine, and engineering must be combined with an interdisciplinary approach to fully address the complexity of mechanical ventilation for further improving patients’ treatment.
Dr Sanchayan Roy
Consultant and HOD of Critical Care Medicine,
VPS Rockland Hospitals
Neonatal and Pediatric Ventilators
Newborn and pediatric care has undergone extensive improvement in the last two decades and advanced respiratory support is at the center of this change. The computer-based technology has made the modern day ventilators more doctor and patient friendly. The synchronized ventilators with volume control and or volume guarantee with advanced pulmonary graphics have helped to make weaning from ventilators easier with lesser side effects. The current day ventilators can be connected with central monitors and can be monitored sitting at a distance as well. The concept of E-ICU wherein the monitoring system is electronic, digital, and real time is likely to pick up in the near future.
On the other hand the concept of gentler ventilation has increased the demand of a CPAP system and heated humidified high-flow nasal cannulae. Many neonatal and pediatric conditions are helped by these relatively simple ventilation techniques. There is more scope of high-frequency ventilators in current day NICU and PICU care and the need of the hour is to have cost-effective high-frequency ventilators. T-piece resuscitators have replaced self-inflating bags in labor rooms and they are being used as transport ventilators also. With the rising cost of intensive care and many sick children requiring home ventilators, we need to build an appropriate medical support system to help such practices.
The challenge which an Indian intensivist faces today is to balance the level of care and its financial implications to the patient. There is a need for making cost-effective ventilators with low running cost. With more wide spread availability of ventilators all across the country, we are seeing increased incidence of healthcare associated infections including ventilator associated pneumonias. There is a great need to impress upon the new generation that there is no replacement of infection prevention strategies in improving the survival and reducing morbidities. The nurses have to be empowered to make that sea change.
Dr Pankaj Garg
Senior Consultant – Department of Neonatology,
Institute of Child Health, Sir Ganga Ram Hospital