Hello, everyone, and welcome to the Society of Critical Care Medicines Pre-Congress course. My name is Javier Amador-Castaneda, and I am the lead respiratory care practitioner in the Medical Intensive Care Unit at Columbia University Urban Medical Center in New York City. And today, we're going to go over respiratory support in ARDS, from high-flow nasal cannula to considerations for lung transplant. Just some quick disclosures. I am the chief executive officer of the Interprofessional Critical Care Network, and my esteemed co-author, Dr. Mina, has been a recipient of several research grants, but there are no conflicts of interest that could potentially bias the content of this presentation. Our learning objectives for today is to understand the new proposed definition of ARDS, to learn various respiratory modalities in the application of the ROCKS index with high-flow nasal cannula, and to comprehend the 10 golden rules for ARDS treatment, as well as to learn the importance of driving pressure and adjunct therapies. Acute respiratory distress syndrome, commonly referred to as ARDS. This is a critical juncture in our discussion, as ARDS is a severe form of acute respiratory failure requiring immediate and evidence-based intervention. ARDS is characterized by the rapid onset of widespread inflammation in the lungs, leading to diffuse alveolar damage. This results in impaired gas exchange and subsequent hypoxemia. Key features of ARDS are severe hypoxemia, bilateral pulmonary infiltrates, and non-cardiogenic pulmonary edema. The pathophysiology of ARDS involves alveolar epithelial and capillary endothelial injury, increased pulmonary vascular permeability, and the accumulation of protein-rich fluid in the alveoli. This may manifest as a rapid onset of dyspnea, hypoxemia refractory to oxygen therapy, and diffuse bilateral opacities on imaging. Early and accurate identification of these features is not only diagnostic but also prognostic, setting the stage for timely and appropriate treatment strategies. Now let's pivot to a broader lens and examine the global ramifications of this syndrome. The statistics are not just numbers. They represent lives, families, and the challenges we face as healthcare providers. When we talk about ARDS affecting approximately 3 million patients globally each year, we're discussing a population larger than many cities. This isn't a rare condition. It's a global health concern. It accounts for 10% of all ICU admissions, making it a frequent challenge that we encounter in critical care settings. And let's not overlook that 27% of these patients require invasive mechanical ventilation. That's more than one in four, underscoring the severity and the resource-intensive nature of managing ARDS. The mortality rates are sovereign, with a 90-day mortality rate of 27% for mild ARDS, 32% for moderate, and a staggering 45% for severe ARDS. Every percentage point here represent lives lost and families affected. But mortality is just the tip of the iceberg. For those who survive, the quality of life and long-term morbidity can be significantly compromised, adding another layer of complexity to patient management. The COVID-19 pandemic has added fuel to the fire. The incidence of ARDS among COVID-19 patients ranges from 6% to 10%, and the mortality rates, they're nothing short of alarming, ranging from 65% to 94% for ventilator patients. This figure serves as a stark reminder of the devastating impact of the pandemic on an already strained healthcare system. As we delve into the understanding of ARDS, it's essential to highlight how our clinical and diagnostic criteria have evolved. Let's walk through the critical milestones that have shaped our current understanding of this severe respiratory condition. We begin in 1967 with the groundbreaking work by Dr. David Aschbach. He coined the term adult respiratory distress syndrome and introduced the clinical manifestations of this profound inflammatory lung condition. This paper laid the cornerstone for future investigations. Fast forward to 1971, when Dr. Petty and Aschbach elaborated upon the clinical and pathological futures of ARDS. Their work served as a guide for early diagnosis and treatment, setting the stage for methodological advances. In 1988, Dr. Murra and colleagues took a quantitative approach by introducing the lung injury score. This tool allowed for a numerical assessment of lung injury severity, providing an objective lens through which ARDS could be evaluated. In 1994, brought us the American-European Consensus Conference, also known as the AECC. This conference expanded the diagnostic criteria for ARDS, further solidifying its clinical understanding. This definition served as the standard for nearly two decades. However, in 2012, the Berlin definition came into play. It refined the diagnostic criteria, but categorizing ARDS into mild, moderate, and severe based on the PaO2 to FiO2 ratio. This brought a greater specificity to ARDS diagnosis and management. In 2015, Dr. Riviello and colleagues broadened the scope by addressing the specific needs and realities of low and middle income countries, also termed as the Kigali modification. This global perspective is indispensable as healthcare paradigms shift towards inclusivity and accessibility. And most recently, Dr. Mathe and his team have presented updates in 2021 and 2023, incorporating the latest diagnostic tools and treatments into a more refined definition of ARDS. So there we have it, a timeline of key advancements, each building up on the last, to equip us with the robust evidence-based understanding of ARDS that we have today. As we continue our discussion on ARDS, it's crucial to understand how the diagnostic criteria are evolving to better serve our patients and adapt to new medical evidence. Over the past decade, we've used the Berlin criteria. Let's look closer at its definition. Let's start with the timing, onset within one week of a non-clinical insult or new or worsening respiratory symptoms. Inflammation levels, classified as mild, moderate, or severe based on the PaO2 to FiO2 ratios. PEEP requirement, a minimum of five centimeters of water pressure of PEEP, typically delivered via invasive mechanical ventilation. In chest imaging, bilateral opacities that are not fully explained by effusions, lung collapse, or nodules. In the origin of edema, respiratory failure not fully explained by cardiac failure or fluid overload. However, the newly proposed global definition for ARDS incorporates four additional criteria to address some limitations. For instance, high flow nasal cannula or non-invasive ventilation, CPAP, requires now a high flow nasal cannula of at least 30 liters per minute or a PEEP or EPAP of five centimeters of water pressure. This is an important addition because patients no longer need to be intubated to be diagnosed with ARDS. Ultrasound imaging. Ultrasound is added as a valid imaging modality for confirming bilateral opacities, especially in resource limited areas. However, this has to be conducted by a trained professional in ultrasound imaging. SpO2 to FiO2 ratio, a ratio of less than 315 with an SpO2 of less than 97%, is now part of the criteria expanding the parameters for hypoxemia measurement. And in resource limited settings, specific respiratory support devices or PEEP levels are no longer mandatory in resource limited settings to diagnose ARDS. These additions represent a significant step forward in making the diagnosis of ARDS more globally applicable, patient-centric, and aligned with the latest evidence-based medicine. The goal is to clearly outline how we are transitioning from the Berlin criteria to a more inclusive and updated global definition for diagnosing ARDS. As we navigate the complexities of ARDS, it becomes evident that one size does not fit all when it comes to respiratory support. Let's delve into the nuanced landscape of available modalities, each with its unique applications and considerations. Aflow nasal oxygen. When we encounter mild ARDS or hypoxemic respiratory failure, high flow often comes to the forefront. Unlike standard oxygen therapy, high flow provides not just improved oxygenation, but also enhanced comfort for the patient. The high flow rates, which can go up to 60 liters per minute, depending on the device utilized, allow for better humidification and a more stable fraction of inspired oxygen. However, it's crucial to monitor for signs of worsening, as high flow may not be sufficient for more severe cases. Noninvasive positive pressure ventilation, also known as NIPPV, is generally our go-to for moderate hypoxemia. The beauty of NIPPV lies in its ability to decrease the work of breathing while avoiding the complications associated with intubation. But let's not forget, it's not a set-and-forget modality. Close monitoring is essential, as failure to improve may necessitate escalation to more invasive measures. Invasive mechanical ventilation, also known as IMV. When we reach the realm of severe ARDS or when other modalities have failed, IMV becomes unavoidable. The control it offers over ventilation parameters is unparalleled. However, this control comes at a cost, the potential to cause ventilator-induced lung injury. Hence, it's imperative to adhere to lung protective strategies while using invasive mechanical ventilation. Extracorporeal membrane oxygenation, also known as ECMO. Finally, when all else fails, ECMO stands as our last line of defense. ECMO allows the lungs to rest and heal by taking over the gas exchange process. But this comes with its own set of challenges, including a high risk of complications like bleeding and infection. So as we move forward, let's keep in mind that the choice of modality is not merely a clinical decision, but a strategic one, balancing efficacy, patient comfort, and risk. The ROCKS index serves as a critical metric for evaluating the success of high-flow nasal cannula therapy in ARDS patients. It is determined by the SpO2 to FiO2 ratio divided by the respiratory rate, with a value below 4.88 after 12 hours of high-flow nasal cannula initiation, suggesting a high risk of therapy failure and the potential need for escalated respiratory support. Separately, the FLORIDALI trial has provided evidence that high-flow nasal cannula can lead to lower 90-day mortality rates in ARDS patients when compared to standard oxygen therapy or non-invasive positive pressure ventilation. In contrast, the ROCKS index is particularly useful for predicting the need for intubation, with higher values indicating a lower risk of requiring invasive mechanical ventilation. The utility of the ROCKS index lies in its ability to inform timely clinical decisions, potentially averting the complications associated with delayed intubation, such as worsened lung mechanics and patient outcomes. While the ROCKS index is a valuable standalone tool, it should be considered alongside other clinical observations, including patient alertness, hemodynamic stability, and respiratory effort to make comprehensive care decisions. We now transition to a critical aspect of ARDS management, the algorithmic approach to utilizing the ROCKS index in patients receiving high-flow nasal cannula. The first step involves evaluating the patient's PF ratio. For those with a PF ratio greater than 300 millimeters of mercury and presenting with no respiratory distress but only mild hypoxemia, standard oxygen therapy is the initial course of action. Conversely, if the PF ratio is below 300 millimeters of mercury and the patient exhibits mild respiratory distress, high-flow nasal cannula therapy is initiated. Patients are then assessed at specific intervals using the ROCKS index, mainly at 2, 4, 6, 12, and beyond 12 hours post-initiation of high-flow nasal cannula therapy. The ROCKS index serves as a pivotal decision-making tool. If the ROCKS index falls below predetermined parameters at any of these time points, clinicians should consider escalating to non-invasive positive pressure ventilation or intubation. On the other hand, if the ROCKS index remains within acceptable parameters, high-flow nasal cannula therapy can be safely continued. This algorithm is grounded in evidence-based practice and provides a structured framework for timely and appropriate interventions in the management of ARDS patients on high-flow nasal cannula. To delve deeper into the complexities of ARDS management, it's imperative to understand the guiding principles for ventilator settings. In the upcoming slides, we will explore the 10 golden rules that serve as a comprehensive framework for optimizing ventilatory support in ARDS. These rules encompass key variables such as tidal volume, plateau pressure, and mechanical power, among others. Rule number one. Rule number one emphasizes the critical importance of maintaining tidal volumes between 4 to 6 mLs per kilogram of predicted body weight, particularly in severe ARDS cases where the PF ratio is below 100 millimeters of mercury. The ARMA trial, this landmark study, establishes that a low tidal volume of 6 mLs per kilogram of predicted body weight significantly improves survival rates in ARDS when compared to higher tidal volumes of 10 to 12 mLs per kilo of predicted body weight. The LUNG-SAFE trial, conducted across 50 countries, this study reported that ARDS was only recognized 60% of the time, and less than two-thirds of ARDS patients receive a tidal volume less than or equal to 8 mLs per kilogram of predicted body weight. In the study by Dr. Needham and colleagues, this research found that every 1 mL per kilogram increase in tidal volume above 6.5 mLs per kilogram was associated with a 23% increase in ICU mortality. On the other hand, the LOVE-ED study, this trial, demonstrated that initiating lung protective ventilation with low tidal volumes and plateau pressures in the emergency department led to its continued use in the ICU, thereby reducing ventilator-induced lung injury and mortality. By adhering to this rule, we not only align our practice with evidence-based medicine, but also optimize patient outcomes in the challenging landscape of severe ARDS. Rule number two. When managing ARDS, plateau pressures are more than just numbers on a ventilator. They're indicators of patient outcomes. Let's examine why keeping these pressures below 20 centimeters of water pressure is vital. The first three days in the ICU are critical. Data shows that plateau pressures exceeding 32 centimeters of water pressure correlate with increased short-term mortality. It's a clear message. Higher pressures can mean higher risk. Research, including a comprehensive meta-regression analysis, pinpoints that 27 centimeters of water pressure as the threshold for plateau pressures. Staying below this value during the initial ICU days is associated with better survival rates. The first day in the ICU is pivotal. A direct link has been found between elevated plateau pressures on day one and a rise in mortality. This underscores the urgency of early pressure management. Interestingly, the significance of plateau pressures on mortality fades after the third day. This suggests a window of opportunity for intervention where pressure management could be most impactful. In summary, maintaining a plateau pressure below 27 centimeters of water pressure, especially during the first critical days post-ICU admission, is essential for improving patient survival in ARDS. It's a targeted strategy that could make a life-saving difference. Rule number three. In our pursuit of optimal ARDS management, we turn our attention to driving pressure. This key ventilator parameter serves as a gauge of lung strain and helps us tailor our ventilation strategy to minimize harm. Driving pressure allows us to estimate lung strain quickly, considering tidal volume and compliance. It's a crucial guide for setting ventilator parameters safely. Driving pressure's correlation with lung aeration provides valuable insights into the lung's condition, informing us about the effectiveness of our ventilation approach. Driving pressure helps us understand the baby lung concept, the portion of the lung still normally inflated, guiding us to protect this vital area during ventilation. Research, including Dr. Cimella's study, shows that high driving pressure is linked to increased lung stress. Keeping driving pressure under 15 centimeters of water pressure is essential to avoid exacerbation lung injury. In essence, maintaining a driving pressure below 15 centimeters of water pressure is a critical step in safeguarding our patient's lungs and ensuring gentle ventilation. In the intricate puzzle of ARDS management, driving pressure is a piece that cannot be overlooked. Driving pressure isn't just a ventilator setting, it's a prognostic marker. Studies have consistently shown that lower driving pressure levels, specifically below 15 centimeters of water pressure, are associated with reduced hospital mortality in moderate to severe ARDS cases. While we often focus on plateau pressure for its importance, driving pressure provides an additional layer of insight. It enhances our predictive capabilities for patient outcomes in ARDS, complementing the data we gather from plateau pressures. In a landscape of various physical variables, driving pressure stands out. A meta-analysis by Dr. Armato and colleagues, encompassing thousands of patients, identify driving pressure as the strongest correlate with survival. This was true even when lung protective ventilation strategies were employed. So what's our takeaway for ventilator settings? It's clear. Aim to keep driving pressure under 15 centimeters of water pressure. But don't stop there. This should be part of a comprehensive approach that includes low tidal volumes, keeping plateau pressures under 27 centimeters of water pressure, and optimizing PEEP for oxygenation. In essence, driving pressure is not just a number to be adjusted, it's a critical guidepost on our route to reducing mortality in ARDS. Rule number four. Rule number four, keep respiratory rate below 30 breaths per minute. The respiratory rate is more than just a number. It's a vital factor influencing lung tissue dynamics and patient outcomes. The lungs aren't just elastic, they're viscoelastic, meaning the response to stress is time dependent. This unique property underscores the importance of carefully timing our ventilatory support. A high respiratory rate can exacerbate both the strain and the rate of strain on lung tissues, potentially heightening the risk of ventilator-induced lung injury. It's not just about the volume, it's about how quickly that volume is being delivered. Different alveoli fill at different rates. This is the concept of time constants. A high respiratory rate may not allow enough time for all alveoli to fill adequately, leading to uneven ventilation and additional strain. Our lungs' extracellular matrix needs time to relax between breaths to reduce strain. A high respiratory rate might cut this crucial relaxation period short, potentially worsening lung injury. It's not just theoretical. Studies have linked high respiratory rates with worse outcomes, including increased mortality and a higher incidence of ventilator-induced lung injury. In conclusion, keeping the respiratory rate below 30 breaths per minute isn't just a guideline. It's a strategy to align with the lungs' viscoelastic nature, optimize alveolar inflation, allow for stress relaxation, and ultimately improve patient outcomes in ARDS. Rule number five. Rule number five. Keep PEEP below 15 centimeters of water pressure, but personalize PEEP. High PEEP levels, especially above 15 centimeters of water pressure, can lead to volume trauma and exacerbate ventilator-induced lung injury by increasing lung stress and strain. It's not just the lungs we're concerned about. Higher PEEP can impinge on cardiovascular function, affecting venous return and cardiac output. We must also consider the right heart. Excessive PEEP can ramp up pulmonary vascular resistance and the workload on the right ventricle. Evidence from significant trials, like the R trial and the alveoli trial, suggest that higher PEEP doesn't necessarily translate to mortality benefits. ARDS isn't a one-size-fits-all condition. High PEEP can be harmful, particularly in patients with non-recruitable lungs, leading to overdistension and reduced compliance. The life study reminds us that ARDS presents in varied morphologies, each demanding a tailored PEEP strategy. By assessing lung recruitability, we can fine-tune PEEP to the individual's pathology. Keeping an eye on driving pressures can guide us to the sweet spot for PEEP, avoiding the extremes that lead to adverse outcomes. A meta-analysis cautions us that high PEEP, even with recruitment maneuvers, might do more harm than good, underscoring the importance of a personalized approach. In essence, while PEEP is a cornerstone of ARDS management, its optimization is not about reaching a numerical high. It's about calibrating to the patient's unique lung characteristics and clinical response, ensuring that we provide supportive care without tipping the scales towards further injury. In this section, we examine the relationship between driving pressure adjustments and individual lung biology. It's essential to recognize that changes in driving pressure are not merely numerical tweaks, but must be informed by individual lung biology. But must be informed by each patient's unique pulmonary mechanics. The accompanying diagrams underscores the importance of not assessing ventilator changes in isolation. Instead, they advocate for a personalized approach using an algorithm to fine-tune PEEP settings. Ensure that our interventions are as responsive and effective as possible at the bedside. So on the right-hand side, we have this table that explains the lung pathology and physiology, followed by the strategy to decrease our driving pressure and what the result is. On the first column right here, we have a compressed but recruitable alveoli. And in order for us to decrease our driving pressure, we increase the PEEP, and therefore we get an optimized alveoli. Meaning that this patient was responsive to an increase in PEEP, and therefore it reduced our driving pressure and it normalized our alveoli. Conversely, we have this compressed, non-recruitable alveoli. We increase the PEEP in an effort to decrease our driving pressure. However, due to this non-recruitable lapse alveolus, in the presence of positive pressure ventilation, it goes to the path of least resistance, and now it caused over-distension of this alveolus. So when we optimize PEEP via driving pressures for this particular non-recruitable patient, this approach did not work. Now on this section, we have an optimized alveoli, and we want to decrease our plateau pressures, and we decrease our tidal volume as a result. And in this case, we get an under-filled alveoli. But on this over-distended alveoli, we decrease our tidal volume, and we get a normally expanded and optimized alveoli. So how do we optimize PEEP via driving pressures? I'll give you a very quick example. Pretend that we have a patient that we're ventilating at 60 cc per kilo of ideal body weight. Let's say that tidal volume happens to be 400 cc, and the patient is on a PEEP of 5. You know that your driving pressure is your plateau pressure minus your total PEEP, meaning the applied PEEP plus any intrinsic PEEP that the patient may be experiencing. So you go ahead and you do an inspiratory hold to get a plateau pressure, and you get a reading of 20. The patient is on a PEEP of 5, so 20 minus 5. In the absence of intrinsic PEEP, you get a driving pressure of 15. So now you go up on the PEEP to try to optimize the driving pressure, and you go, let's say, to make the numbers easy, you go from a PEEP of 5 to a PEEP of 10. And you conduct another inspiratory hold, and now you have a plateau pressure of 20 again. 20 minus 10 is 10. So your driving pressure shortened, and it went from a driving pressure of 20 down to a driving pressure of 10, meaning that the patient was responsive to the PEEP, and you experienced some recruitable alveoli that you were able to expand. So you don't stop there. You keep going, and you keep optimizing PEEP until you get the shortest driving pressure. So pretend that now you go from a PEEP of 10 to a PEEP of 15. You do another inspiratory hold, and you get a plateau pressure of 30. Again, in the absence of intrinsic PEEP, 30 minus 15 is 15. So now your driving pressure went from 10 back up to 15. Now we're over-extending the alveoli. Now we're giving too much PEEP. So then you would go back to the PEEP that gave you the shortest amount of driving pressure, which will be a PEEP of 10, because that's when you got a driving pressure of 10. And as you know, we want to keep our driving pressures below 15 centimeters of water pressure, because that correlates with better survival rates. Rule number six. Rule number six. Keep mechanical power less than 17 joules per minute. Consider ECMO if it's more than 17 joules per minute. Mechanical power is a pivotal concept in mechanical ventilation, grounded in the principles of the first law of thermodynamics, which states that energy is conserved and merely transformed from one form to another. In the setting of mechanical ventilation, electrical energy is converted into potential, kinetic, and ultimately heat energy. This energy is harnessed to generate the pressure needed to move air or tidal volume into the lungs. The significance of mechanical power lies in its potential impact on the lung parenchyma. As energy is transferred to the lungs with each breath, it can induce structural changes at both the cellular and tissue levels, contributing to ventilator-induced lung injury. This energy transfer, termed mechanical energy, when quantified over time, is referred to as mechanical power. In respiratory physiology, mechanical power is conventionally measured in joules per minute. Understanding the implications of mechanical power is crucial in the management of ARDS. Observational studies have indicated that mechanical power values exceeding 17 joules per minute are associated with higher mortality rates in general ICU patients, and this risk is further amplified in ARDS patients when mechanical power surpasses 22 joules per minute. Experimental models have shown that a mechanical power threshold above 25 joules per minute can lead to significant lung damage, which may be irreversible and fatal. In the context of ECMO and mechanical power greater than 17 joules per minute during the first three days, is linked with an increased risk of 90-day hospital mortality. This underscores the importance of closely monitoring mechanical power and considering ECMO as a viable option when the threshold is exceeded. Mechanical power is not just a number. It represents the cumulative impact of ventilatory parameters on the lungs. By providing a comprehensive view of the energy dynamics in mechanical ventilation, mechanical power serves as a guide for clinicians to tailor lung protective strategies, aiming to strike a balance between delivering adequate respiratory support and minimizing the risk of further lung injury. Rule number seven. Rule number seven. From positioning for 12 to 18 hours if PF ratios below 150 millimeters of mercury. Dr. Guerin and colleagues conducted a multi-center perspective randomized controlled trial encompassing 466 patients that has provided us with compelling evidence. The study's inclusion criteria consisted of a PF ratio under 150, an FIO2 of at least 60%, a PEEP of no less than 5 centimeters of water pressure, and a tidal volume approximating 6 mLs per kilogram of predicted body weight. The intervention was straightforward yet powerful. Patients assigned to the prone group were positioned for sessions extending at least 16 hours. The results were striking. A significant reduction in 28-day mortality with only 16% in the prone group versus 32.8% in the supine group. This remarkable benefit extended beyond the immediate horizon with a pronounced decrease in unadjusted 90-day mortality as well. 23.6% compared to 41% in the supine group translating to a hazard ratio of 0.44. But what about the safety? The study addressed this concern head-on revealing no significant increase in complications due to prone positioning. This positions prone therapy not only as effective but also as a safe intervention for those grappling with the severest form of ARDS. Rule number 8. Rule number 8. Use of neuromuscular blocking agents in severe ARDS when appropriate. Neuromuscular blocking agents in the context of severe ARDS present a complex therapeutic puzzle. They are invariably paired with sedatives and analgesics ensuring deep sedation and facilitating passive mechanical ventilation. Yet, the medical community stands divided on the routine application. While meta-analyses have explored the potential benefit of reducing active respiratory efforts, a clear consensus remains elusive. For a duration of 48 hours, neuromuscular blocking agents have demonstrated an ability to enhance oxygenation and potentially lower the risk of barotrauma in moderate to severe cases of ARDS. However, the clarity ends there. When we look at the long-term outcomes, mortality, ventilator-free days, and the duration of mechanical ventilation, the impact of neuromuscular blocking agents becomes murkier. Guidelines have cautiously approached this uncertainty. They suggest that neuromuscular blocking agents may be considered in the early stages of severe ARDS, especially when deep sedation and invasive mechanical ventilation are coupled with prone positioning within the initial 48-hour window. Yet, they stop short of endorsing widespread routine use. In essence, the current stance on neuromuscular blocking agents is one of careful consideration, reserving their use for specific clinical scenarios rather than a blanket approach for all ARDS patients. This nuanced perspective underscores the importance of individualized patient care and the need for ongoing research to illuminate the path forward. Rule number nine. Rule number nine, recruitment maneuvers. Although useful, it is not routinely recommended. Recruitment maneuvers in ARDS management have been a subject of intense scrutiny. Recent evidence from a comprehensive randomized trial involving 1,010 patients with moderate to severe ARDS has cast a shadow on the efficacy of these strategies. The trial revealed a stark increase in 28-day mortality for patients undergoing long recruitment and PEEP titration, with figures rising to 55.3% compared to 49.3% in those following a conventional low PEEP strategy. The long-term outlook is equally concerning, with a six-month mortality rate of 65.3% observed in the recruitment maneuver group, a noticeable increase from the 59.9% in the control group. This approach also resulted in a reduction of ventilator-free days, suggesting a prolonged dependency on mechanical ventilation. Complications such as pneumothorax requiring drainage and barotrauma were notably higher in the recruitment maneuver cohort, raising serious questions about the safety of these interventions. Interestingly, the length of ICU and hospital stays did not significantly differ between the two groups, indicating that the adverse effects of recruitment maneuvers are more closely associated with mortality and morbidity rather than the duration of hospital care. These findings have significant clinical implications, urging a more cautious and selective application of recruitment maneuvers. The routine incorporation of these strategies in ARDS treatment protocols may need to be re-evaluated, with a preference for their use only in cases where clinical signs of long-term recruitment and desaturation are evident. This tailored approach could potentially mitigate the risk associated with recruitment maneuvers, aligning treatment more closely with patient-specific conditions. Rule number 10. Rule number 10, consider ECMO. Extracorporeal membrane oxygenation represents a pivotal intervention in the management of severe ARDS, offering a potential lifeline when conventional therapies fail. The CSER trial, followed by the EOLIA trial, has shed light on the promise of ECMO, suggesting a possible enhancement in survival and quality of life. Though definitive statistical significance remain elusive, a critical insight from the EOLIA trial's post-hoc analysis is the suggestion that the timing of ECMO initiation may be a key determinant of its effectiveness. This underscores the importance of early consideration and application of ECMO in the treatment algorithm for severe ARDS, particularly when conventional methods are not yielding the desired results. In the context of the COVID-19 pandemic, ECMO has gained attention for its role in managing critically ill patients. Evidence points to its efficacy in severe cases, especially for those with a PF ratio below 80 mmHg, where it has been associated with reduced mortality rates. Moreover, ECMO facilitates lung protective ventilation by allowing for the maintenance of lower driving pressure, which is crucial given the association of high driving pressure with increase in hospital mortality. By reducing ventilatory demands and providing adequate gas exchange, ECMO can minimize ventilator-induced lung injury, offering a dual benefit in the management of severe ARDS. In conclusion, ECMO remains a critical consideration for severe ARDS, particularly when timely applied. It stands as a testament to the advancement in critical care, providing a bridge to recovery or decision-making in otherwise dire circumstances. We have briefly discussed some of the adjunct therapies, such as low tidal volume protective ventilation, as well as prone positioning. Now let's go over some of the adjunct therapies that we have not covered. There are many adjunct therapies, and we have already covered some of them, such as low tidal volume ventilation, prone positioning ventilation, neuromuscular blocking agents. But now let's talk about fluid management and the use of corticosteroids. The Fluid and Catheter Treatment Trial, also known as the FACT Trial, offers a comprehensive analysis of fluid management strategies in ARDS, comparing conservative versus liberal approaches. Let's talk about the conservative fluid management highlights. On the 60-day mortality, there were no significant difference in mortality rates at 60 days compared to the liberal strategy. In terms of the fluid balance, a negative mean cumulative fluid balance at 7 days, suggesting effective fluid removal. On lung function, there was an improvement oxygenation index and lung injury scores, indicating enhanced lung function. An increased ventilator free days, reflecting quicker weaning from mechanical ventilation, and more days out of the ICU within the first 28 days, suggesting a faster recovery. There were no significant increase in the need for dialysis or shock incidents. Now let's talk about the liberal fluid management highlights. In terms of 60-day mortality, it was comparable mortality rates at 60 days to the conservative strategy. For fluid balance, there was a positive mean cumulative fluid balance, showing greater fluid retention. There were fewer ventilator free days, indicating prolonged mechanical ventilation, and less ICU free days within the first 28 days, suggesting a slower recovery process. A non-significant trend towards increased dialysis use, hinting at potential renal stress. The FACT trial underscores the importance of teller fluid management in ARDS. The conservative strategy with its association with improved lung function and more ventilator free days presents a compelling case for managing fluid balance judiciously. It highlights that conservative fluid management can be safely implemented without increasing the risk of renal dysfunction or shock. These findings advocate for a more nuanced approach to fluid therapy in the critical care of ARDS patients, aligning with the goals of optimizing respiratory function and facilitating recovery. Now let's talk about the use of critical steroids in ARDS patients. A pivotal multi-center trial conducted across 17 ICUs in Spain, authored by Dr. Villar and colleagues, and published as Dexamethasone Treatment for Acute Respiratory Distress Syndrome, a multi-center randomized controlled trial, illuminates the efficacy of critical steroids in ARDS management. Let's talk about some of the key aspects of the study. The exclusion of patients with conditions such as brain death, terminal diseases, but also in critical steroids, immunosuppressants, ensure a focused and relevant study group. Patients in the treatment arm receive a carefully structured regimen of dexamethasone, tapering from 20 milligrams to 10 milligrams over a 10-day period. Consistent with best practices, all participants were managed with lung protective mechanical ventilation strategies. Some of the primary findings were a significant increase in ventilator free days that was noted in the dexamethasone group, indicating enhanced respiratory recovery. The dexamethasone group showed a marked reduction in 60-day mortality, pointing to a potential survival advantage. Rates of adverse events, such as hyperglycemia, new infections, and biotrauma, were similar between the treatment and control groups. The study by Dr. Villar and colleagues suggests that early administration of dexamethasone in patients with established moderate to severe ARDS can lead to a substantial decrease in the duration of mechanical ventilation and a significant reduction in mortality rates without an increase in adverse events. These findings advocate for the strategic inclusion of dexamethasone in ARDS treatment protocols, reinforcing its potential to improve patient outcomes, minimize the duration of mechanical ventilation, and enhance survival rates in this critical patient population. Now, let's briefly talk about lung transplant. Lung transplantation has emerged as a potential rescue therapy for patients with severe ARDS. Here are the evidence-based considerations from recent studies. First, let's go over the etiology and intensive care requirements. All infections were the leading cause of ARDS in over half of the case studies, roughly 53.8%. All patients required admissions to the intensive care unit, and all patients necessitated mechanical ventilation. A significant portion, 11 out of 13, were on ECMO at the time of listing for transplantation. The median lung allocation score was about 76, indicating a high level of urgency, and the median waiting time for a transplant was notably short at just three days. Post-surgery, the median duration of mechanical ventilation was about 33 days, and patients typically spend 39 days in the ICU and 54 days in the hospital. Over half of the patients, roughly 53.8%, require ECMO post-operatively for a median duration of two days. In terms of survival rates, the 30-day mortality rate post-transplant was remarkably low at 7.7%. The one-year survival rate was 71.6%, and the five-year survival rate was about 54.2%. This finding suggests that lung transplantation can be a viable rescue therapy for select patients with severe ARDS, offering a chance for extended survival. However, it requires careful consideration of patient selection, timing, and post-operative care to optimize outcomes. As we conclude this presentation, I'd like to emphasize four crucial points that I hope you'll carry forward in your practice. Number one, early diagnosis of ARDS. The first and foremost is the early diagnosis of ARDS. It's imperative to recognize ARDS as soon as possible. Remember, intubation is no longer a prerequisite for an ARDS diagnosis. We need to move beyond merely labeling conditions as acute hypoxemic respiratory failure and waiting for a progression through various stages of respiratory support before acknowledging ARDS. Early identification is key. If a patient meets the ARDS criteria while on high-flow nasal cannula, diagnose them accordingly. This approach helps us intervene before the transition from the exudative to the proliferative phase, where we often lose our window of opportunity for optimal treatment. Number two, proactive intervention. My second point revolves around early intervention. With tools like the ROCKS Index at our disposal, we can better monitor patients for high-flow nasal cannula failure or success. It's crucial to be vigilant, especially as patients transition from mild to moderate ARDS. Don't wait for the condition to escalate to severe ARDS before considering intubation. Use the ROCKS Index to guide your decision and intervene early. Early intervention is pivotal for improving patient outcomes. Number three, adherence to the 10 golden rules. Once a patient is intubated, it's vital to adhere to the 10 golden rules in managing ARDS. These guidelines are designed to optimize patient outcomes and should be a cornerstone of your treatment approach. And last but not least, understanding and utilizing driving pressure. The importance of driving pressure cannot be overstated. It serves two main purposes, maintaining it below 15 centimeters of water pressure to reduce mortality rates and using it to optimize PEEP for better patient ventilation. We need to evolve from the one-size-fits-all approach of low tidal volume ventilation based on predicted body weight. Instead, our focus should shift from what I call optimized driving pressure ventilation. This method prioritizes ventilating the functional lung units available at any given time rather than adhering strictly to calculations based on predicted body weight. These four points are essential in enhancing our approach to ARDS management, ultimately leading to better patient care and outcomes. Thank you all for your time, and this concludes my presentation. I hope to see you guys at Congress. Before we part ways, I would like to draw your attention to the last slide, which contains my contact information. If you have any further questions or wish to delve deeper into any of the topics we've discussed, please feel free to scan the QR code provided and send me your inquiries. I am more than happy to respond and engage in further discussions. Moreover, I encourage you to share your thoughts and questions. It's possible that some of the queries you have might also be on the minds of others. Therefore, with your permission, I would like to bring some of these questions to our in-person presentation at the Congress. This will allow us to address any additional concerns and enrich our collective learning experience. Your input is invaluable, and I look forward to continuing our dialogue beyond this virtual platform. Thank you once again for your active participation and for making this course a success.

Acute Respiratory Distress Syndrome

pathophysiology

epidemiology

diagnostic criteria

ROCKS Index

ventilator settings

adjunct therapies

fluid management