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Critical care guidelines—more science less art?
Editorial
Deciding when a mechanically ventilated patient is able to start breathing on their own is an inexact science. The underlying cause of respiratory failure, duration of mechanical ventilation, age of the patient, and their comorbidities all have an effect on the success of extubation. Prolonged mechanical ventilation increases the chance of complications such as ventilator-associated pneumonia and volutrauma but extubation failure is also associated with poor outcomes and increased mortality. In an attempt to aid clinicians in this challenging decision the American College of Chest Physicians (CHEST) and the American Thoracic Society (ATS) have published new guidelines on the “Liberation from mechanical ventilation in critically ill adults”. The new guidelines aimed to update the previous ones published by CHEST in 2001 by answering six new clinical questions. However, despite incorporating evidence from studies published in the last 15 years, only one of the six statements comes with a strong recommendation—to transition from mechanical ventilation to preventative non-invasive ventilation for patients at high risk for extubation failure who have passed a spontaneous breathing trial. All other recommendations were considered conditional, with moderate to very low certainty in the evidence. The guidelines conclude that the conditional recommendations are “limited by the quality of the available evidence” and one of the authors of the guidelines, Dr Girrard (University of Pittsburgh, PA, USA), said that almost every question they looked at needed additional studies. During the intricate care of ICU patients, it is not surprising that one study found full adherence to guidelines was as low as 24%. So although guidelines might offer the best available expert advice based on current research, if the underlying evidence is inadequate how useful will they be and how can the evidence base be improved? Critical care has many unique challenges that make research difficult. First, significant hurdles exist regarding informed consent. Most critical care patients are unable to consent themselves and combined with the time-sensitive nature of beginning treatment in life-threatening situations recruitment of patients for trials is deprioritised. Second, the patient population is incredibly heterogenous. Even when patients have www.thelancet.com/respiratory Vol 4 December 2016
a common diagnosis such as acute respiratory distress syndrome (ARDS) the patients within that group can have many different underlying causes and severity of disease. Another unique challenge to critical care is that the ICU is staffed by health-care practitioners from a variety of specialties (emergency medicine, respiratory, and anaesthesia) and looks after patients with multisystem disease. This set up not only makes funding more difficult to apply for (a traditionally diseasecentred system), but means that hypotheses might not be shared between different departments and research hindered unless cross-specialty collaboration occurs. In 2012, CHEST published recommendations from the Multisociety Task Force for critical care research about the need to breakdown the previously insular approach to critical care research and more effectively link areas such as basic and translational research with frontline clinical care. The report also stressed the importance of accounting for patient heterogeneity and multisystem illness, and how building an infrastructure for critical care research will help overcome regulatory challenges, build research networks and increase funding. Guidelines and protocols are important to standardise care and maintain high standards but simplifying critical care patients with multisystem diseases into one end diagnosis has resulted in many trials showing no benefit of treatment. As our understanding of conditions such as sepsis and ARDS improves, heterogeneity in trials could be reduced through filtering patient enrollment by age, site of infection or pathogen, as well as establish subphenotypes (through biomarkers linked to underlying pathophysiology) that might benefit more from certain treatments and make the analysis of trials clearer and more applicable. Where does this leave the critical care physician faced with extubating a complex patient? I think most clinicians would say that having a group of experts in your field synthesise current evidence and recommend a certain course of action (even if only conditionally) is still useful. The conditional aspect also leaves room for the “art” of tailoring your treatment plan for the unique patient in front of you. But as the evidence grows, and we learn more about how to categorise and treat these complex patients, hopefully there will be more science and less art. ■ The Lancet Respiratory Medicine
Carol and Mike Werner/SPL
Critical care guidelines—more science less art?
For the ATS guidelines see http://www.atsjournals.org/doi/ abs/10.1164/rccm.2016102076ST?utm_ source=Informz&utm_ medium=Email&utm_ campaign=Informz+Mailing For the 2001 guidelines published by CHEST see http://www.sciencedirect.com/ science/article/pii/ S0012369215499970 For more on compliance to the guidelines see https://www.ncbi.nlm.nih.gov/ pubmed/23027124 For more on research of the Multisociety Task Force see https://www.ncbi.nlm.nih.gov/ pmc/articles/PMC3251271/
925
Deciding when a mechanically ventilated patient is able to start breathing on their own is an inexact science. The underlying cause of respiratory failure, duration of mechanical ventilation, age of the patient, and their comorbidities all have an effect on the success of extubation. Prolonged mechanical ventilation increases the chance of complications such as ventilator-associated pneumonia and volutrauma but extubation failure is also associated with poor outcomes and increased mortality. In an attempt to aid clinicians in this challenging decision the American College of Chest Physicians (CHEST) and the American Thoracic Society (ATS) have published new guidelines on the “Liberation from mechanical ventilation in critically ill adults”. The new guidelines aimed to update the previous ones published by CHEST in 2001 by answering six new clinical questions. However, despite incorporating evidence from studies published in the last 15 years, only one of the six statements comes with a strong recommendation—to transition from mechanical ventilation to preventative non-invasive ventilation for patients at high risk for extubation failure who have passed a spontaneous breathing trial. All other recommendations were considered conditional, with moderate to very low certainty in the evidence. The guidelines conclude that the conditional recommendations are “limited by the quality of the available evidence” and one of the authors of the guidelines, Dr Girrard (University of Pittsburgh, PA, USA), said that almost every question they looked at needed additional studies. During the intricate care of ICU patients, it is not surprising that one study found full adherence to guidelines was as low as 24%. So although guidelines might offer the best available expert advice based on current research, if the underlying evidence is inadequate how useful will they be and how can the evidence base be improved? Critical care has many unique challenges that make research difficult. First, significant hurdles exist regarding informed consent. Most critical care patients are unable to consent themselves and combined with the time-sensitive nature of beginning treatment in life-threatening situations recruitment of patients for trials is deprioritised. Second, the patient population is incredibly heterogenous. Even when patients have www.thelancet.com/respiratory Vol 4 December 2016
a common diagnosis such as acute respiratory distress syndrome (ARDS) the patients within that group can have many different underlying causes and severity of disease. Another unique challenge to critical care is that the ICU is staffed by health-care practitioners from a variety of specialties (emergency medicine, respiratory, and anaesthesia) and looks after patients with multisystem disease. This set up not only makes funding more difficult to apply for (a traditionally diseasecentred system), but means that hypotheses might not be shared between different departments and research hindered unless cross-specialty collaboration occurs. In 2012, CHEST published recommendations from the Multisociety Task Force for critical care research about the need to breakdown the previously insular approach to critical care research and more effectively link areas such as basic and translational research with frontline clinical care. The report also stressed the importance of accounting for patient heterogeneity and multisystem illness, and how building an infrastructure for critical care research will help overcome regulatory challenges, build research networks and increase funding. Guidelines and protocols are important to standardise care and maintain high standards but simplifying critical care patients with multisystem diseases into one end diagnosis has resulted in many trials showing no benefit of treatment. As our understanding of conditions such as sepsis and ARDS improves, heterogeneity in trials could be reduced through filtering patient enrollment by age, site of infection or pathogen, as well as establish subphenotypes (through biomarkers linked to underlying pathophysiology) that might benefit more from certain treatments and make the analysis of trials clearer and more applicable. Where does this leave the critical care physician faced with extubating a complex patient? I think most clinicians would say that having a group of experts in your field synthesise current evidence and recommend a certain course of action (even if only conditionally) is still useful. The conditional aspect also leaves room for the “art” of tailoring your treatment plan for the unique patient in front of you. But as the evidence grows, and we learn more about how to categorise and treat these complex patients, hopefully there will be more science and less art. ■ The Lancet Respiratory Medicine
Carol and Mike Werner/SPL
Critical care guidelines—more science less art?
For the ATS guidelines see http://www.atsjournals.org/doi/ abs/10.1164/rccm.2016102076ST?utm_ source=Informz&utm_ medium=Email&utm_ campaign=Informz+Mailing For the 2001 guidelines published by CHEST see http://www.sciencedirect.com/ science/article/pii/ S0012369215499970 For more on compliance to the guidelines see https://www.ncbi.nlm.nih.gov/ pubmed/23027124 For more on research of the Multisociety Task Force see https://www.ncbi.nlm.nih.gov/ pmc/articles/PMC3251271/
925