COMMENTARY
Ultrasound and the Six Thinking Hats
E
dward de Bono, the physician, author, and leading authority in the field of creative thinking, advocated methodical teaching of thinking as a subject in schools. He describes a tool for thoughtful analysis of decisions from a variety of perspectives involving six colored hats.1 “Six Thinking Hats” and the related idea of “parallel thinking” organizes the thinking processes in a detailed and cohesive way and in doing so improves the efficiency of thinking. Each of the six distinct perspectives proposed by Edward de Bono are assigned a color as follows: 1) managing (blue) refers to overall understanding of the subject and topic; 2) informational (white) pertains to discussion of the facts; 3) optimistic (yellow) focuses on identifying benefits and value; 4) emotional (red) refers to intuitive, instinctive, and emotional gut reactions; 5) discerning (black) involves critical analysis to be cautious and conservative; and 6) creative (green) proposes statements of provocation and investigation, seeing where a thought goes.1 In this issue of Academic Emergency Medicine, Al Deeb et al.2 present a systematic review of ultrasound (US) in the diagnosis of pulmonary edema. Applying De Bono’s principles to this review delineates the strengths and limitations of US and its application in clinical practice. This approach can also help us analyze the overall progress in the field of US research. Ultrasound’s key strength as a medical imaging technology is in its ability to accurately view anatomic solid organs, as soft tissue and fluid are excellent transmitters of sound waves. Conversely, as air is a barrier to US, visualization of lungs was previously considered not feasible. This paradigm prevailed for decades until an innovative image interpretation technique, relying heavily on the analysis of artifacts and correlating their patterns with pathologic disease processes, allowed the field of lung US to flourish. That same spirit of innovation created the subspecialty of emergency US, or more broadly, point-of-care US. The crux of point-of-care US as a diagnostic modality is its real-time bedside incorporation in a novel way into the clinical algorithm. While maybe commonplace now, US examination performed by the emergency physician to answer focused clinical questions was a radical deviation from traditional practice. Since its origins in the
The authors have no relevant financial information or potential conflicts of interest to disclose. A related article appears on page 844.
920 920
ISSN 1069-6563 920 PII ISSN 1069-6563583
1970s, the field of emergency US has grown by leaps and bounds. Its scope of practice is well defined3 and continues to expand. US performance and interpretation is a required component of postgraduate emergency medicine education,4,5 and teaching at undergraduate and fellowship levels is increasingly prevalent. This growth of the subspecialty is mirrored also in the evolution of emergency US research. The earliest literature in emergency US involved case reports and case series describing the novel practice. Following these initial studies, the practice was validated by various studies comparing the results of emergency physicians as sonologists versus those of traditional image specialists. Aimed at addressing image quality and technical expertise by nontraditional users, feasibility and noninferiority were demonstrated. Subsequently, comparative and outcomes research trials attempted to establish diagnostic efficacy. Now with a growing volume of research, systematic reviews and meta-analyses are published in the field of emergency US, evidence of a maturation of the field. The benefits and values of bedside US in diagnosing pulmonary edema are examined in the article by Al Deeb et al.2 The systematic review demonstrates a correlation between sonographic B-lines and pulmonary edema in dyspneic patients. The authors quantify this correlation to a sensitivity and specificity of 94 and 92%, respectively. The results indicate that clinician-sonologists now can use this rapid, noninvasive, inexpensive, reproducible, safe, and accurate way to rule in or rule out pulmonary edema as a cause of dyspnea at the bedside. The potential to decrease the need for chest radiography or certain laboratory tests such as brain natriuretic peptide is real and could have implications for patient safety and health care costs. It is important, of course, to recognize that any diagnostic test must be incorporated into initial clinical findings and overall gestalt. Clinical gestalt or “gut feeling” about the probability of the patient having a disease together with the prevalence of the disease form the clinicians’ pretest probability.6 In the case of pulmonary edema, with a positive likelihood ratio of 12.4 and a negative likelihood ratio of 0.06, US has the ability to significantly alter pretest probability of the disease and potentially produce an actionable (very high or very low) posttest probability.6 US does not replace medical history, physical examination, or clinical judgment. It rather serves as a tool to increase or decrease the probability of the disease to a level that could prompt finalizing the diagnosis and streamlining the treatment.
© 2014 by the Society for Academic Emergency Medicine doi: 10.1111/acem.12438
ACADEMIC EMERGENCY MEDICINE • August 2014, Vol. 21, No. 8 • www.aemj.org
Systematic reviews are generally considered among the upper echelon of level of evidence because they critically analyze the results of the trials that attempt to address any particular research question. However, certain limitations always warrant caution when interpreting the results of systematic reviews. If the quality of the studies addressing the research question is poor, the level of evidence produced by them would be low. Systematic reviews must critically assess the quality of evidence, as this directly affects the extent of our confidence that the estimates of the effect are correct.7 Apart from the quality of the included trials, heterogeneity of the trials always creates a challenge.8 Differences in study population, study settings, and details of the study design (e.g., inclusion/exclusion criteria) could make comparison of the trials very difficult. US research in particular is subject to additional sources of heterogeneity. Point-of-care US consists of two primary components: image acquisition (procedural skill) and image interpretation (pattern recognition). In image acquisition, operator experience, lack of standardization of scanning protocols, use of varied US machines and probes, and different patient position during US imaging contributes to the heterogeneity of research methods. These issues are well highlighted in the systematic review by Al Deeb et al.2 In image interpretation, variations in diagnostic criteria and operator dependence can influence results of findings. In the studies included in this systematic review the diagnostic criteria for B-lines were different (Volpicelli, Comet score, and Lichtenstein methods), and the interobserver reliability for visualizing B-lines by operators was not measured in most of the included trials.2 These factors contribute to increased risk of bias in studies and reduced generalizability of the results. As consumers of evidence, a clinician-reader of a systematic review must carefully judge both reported study quality and outcome effect, to determine if practice change is warranted.8 From the perspective of further investigation, a natural next step would be to standardize scanning protocols and further limit heterogeneity among various studies by creating clear training guidelines for the operators acquiring and interpreting the images. Finally, once diagnostic parameters are better defined, research can progress to assessing more patient-oriented outcomes, effects on decision-making, and cost-effective analyses. Improvement in quality of US research in the past decade promises more and more high-quality trials and higher levels of evidence in the near future. Such trials could pave way for higher-quality systemic reviews, meta-analyses, and clinical guidelines and ultimately result in translating more high-level evidence into clinical practice (i.e., knowledge translation). Application of De Bono’s principles of the Six Thinking Hats provides a framework for analysis of US research and systematic reviews produced based on these trials. Readers are encouraged to pay special attention to the quality of the trials included in systematic reviews and the existing heterogeneity among the trials. This critical approach could help clinicians safely and expertly incorporate the evidence
921
produced by these trials and systematic reviews into clinical practice. As Edward de Bono once stated, “An expert is someone who has succeeded in making decisions and judgments simpler through knowing what to pay attention to and what to ignore.”1 Yiju T. Liu, MD Kaiser Permanente Mid Atlantic Rockville, MD Shahriar Zehtabchi, MD ([email protected]) Department of Emergency Medicine State University of New York Downstate Medical Center Brooklyn, NY Andrew S. Liteplo, MD Department of Emergency Medicine Massachusetts General Hospital Harvard Medical School Boston, MA
Supervising Editor: David C. Cone, MD.
References 1. De Bono E. Six Thinking Hats: An Essential Approach to Business Management. New York, NY: Little Brown and Company, 1985. 2. Al Deeb M, Barbic S, Featherstone R, Dankoff J, Barbic D. Point-of-care ultrasonography for the diagnosis of acute cardiogenic pulmonary edema in patients presenting with acute dyspnea: a systematic review and meta-analysis. Acad Emerg Med 2014;21:844– 852. 3. American College of Emergency Physicians. Emergency Ultrasound Guidelines. Available at: http:// www.acep.org/Clinical—Practice-Management/Ultra sound. Accessed May 25, 2014. 4. Accreditation Council for Graduate Medical Education. Emergency Medicine Guidelines. Available at: http://dconnect.acgme.org/acWebsite/RRC_110/110_ guidelines.asp. Accessed May 25, 2014. 5. Jang TB, Coates WC, Liu YT. The competency-based mandate for emergency bedside sonography training and a tale of two residency programs. J Ultrasound Med 2012;31:515–21. 6. Zehtabchi S, Kline JA. The art and science of probabilistic decision-making in emergency medicine. Acad Emerg Med 2010;17:521–3. € nemann HJ, et al. 7. Balshem H, Helfand M, Schu GRADE guidelines: 3. Rating the quality of evidence. J Clin Epidemiol 2011;64:401–6. 8. Guyatt GH, Oxman AD, Kunz R, et al. GRADE guidelines: 7. Rating the quality of evidence–inconsistency. J Clin Epidemiol 2011;64:1294–302.
Ultrasound and the Six Thinking Hats
E
dward de Bono, the physician, author, and leading authority in the field of creative thinking, advocated methodical teaching of thinking as a subject in schools. He describes a tool for thoughtful analysis of decisions from a variety of perspectives involving six colored hats.1 “Six Thinking Hats” and the related idea of “parallel thinking” organizes the thinking processes in a detailed and cohesive way and in doing so improves the efficiency of thinking. Each of the six distinct perspectives proposed by Edward de Bono are assigned a color as follows: 1) managing (blue) refers to overall understanding of the subject and topic; 2) informational (white) pertains to discussion of the facts; 3) optimistic (yellow) focuses on identifying benefits and value; 4) emotional (red) refers to intuitive, instinctive, and emotional gut reactions; 5) discerning (black) involves critical analysis to be cautious and conservative; and 6) creative (green) proposes statements of provocation and investigation, seeing where a thought goes.1 In this issue of Academic Emergency Medicine, Al Deeb et al.2 present a systematic review of ultrasound (US) in the diagnosis of pulmonary edema. Applying De Bono’s principles to this review delineates the strengths and limitations of US and its application in clinical practice. This approach can also help us analyze the overall progress in the field of US research. Ultrasound’s key strength as a medical imaging technology is in its ability to accurately view anatomic solid organs, as soft tissue and fluid are excellent transmitters of sound waves. Conversely, as air is a barrier to US, visualization of lungs was previously considered not feasible. This paradigm prevailed for decades until an innovative image interpretation technique, relying heavily on the analysis of artifacts and correlating their patterns with pathologic disease processes, allowed the field of lung US to flourish. That same spirit of innovation created the subspecialty of emergency US, or more broadly, point-of-care US. The crux of point-of-care US as a diagnostic modality is its real-time bedside incorporation in a novel way into the clinical algorithm. While maybe commonplace now, US examination performed by the emergency physician to answer focused clinical questions was a radical deviation from traditional practice. Since its origins in the
The authors have no relevant financial information or potential conflicts of interest to disclose. A related article appears on page 844.
920 920
ISSN 1069-6563 920 PII ISSN 1069-6563583
1970s, the field of emergency US has grown by leaps and bounds. Its scope of practice is well defined3 and continues to expand. US performance and interpretation is a required component of postgraduate emergency medicine education,4,5 and teaching at undergraduate and fellowship levels is increasingly prevalent. This growth of the subspecialty is mirrored also in the evolution of emergency US research. The earliest literature in emergency US involved case reports and case series describing the novel practice. Following these initial studies, the practice was validated by various studies comparing the results of emergency physicians as sonologists versus those of traditional image specialists. Aimed at addressing image quality and technical expertise by nontraditional users, feasibility and noninferiority were demonstrated. Subsequently, comparative and outcomes research trials attempted to establish diagnostic efficacy. Now with a growing volume of research, systematic reviews and meta-analyses are published in the field of emergency US, evidence of a maturation of the field. The benefits and values of bedside US in diagnosing pulmonary edema are examined in the article by Al Deeb et al.2 The systematic review demonstrates a correlation between sonographic B-lines and pulmonary edema in dyspneic patients. The authors quantify this correlation to a sensitivity and specificity of 94 and 92%, respectively. The results indicate that clinician-sonologists now can use this rapid, noninvasive, inexpensive, reproducible, safe, and accurate way to rule in or rule out pulmonary edema as a cause of dyspnea at the bedside. The potential to decrease the need for chest radiography or certain laboratory tests such as brain natriuretic peptide is real and could have implications for patient safety and health care costs. It is important, of course, to recognize that any diagnostic test must be incorporated into initial clinical findings and overall gestalt. Clinical gestalt or “gut feeling” about the probability of the patient having a disease together with the prevalence of the disease form the clinicians’ pretest probability.6 In the case of pulmonary edema, with a positive likelihood ratio of 12.4 and a negative likelihood ratio of 0.06, US has the ability to significantly alter pretest probability of the disease and potentially produce an actionable (very high or very low) posttest probability.6 US does not replace medical history, physical examination, or clinical judgment. It rather serves as a tool to increase or decrease the probability of the disease to a level that could prompt finalizing the diagnosis and streamlining the treatment.
© 2014 by the Society for Academic Emergency Medicine doi: 10.1111/acem.12438
ACADEMIC EMERGENCY MEDICINE • August 2014, Vol. 21, No. 8 • www.aemj.org
Systematic reviews are generally considered among the upper echelon of level of evidence because they critically analyze the results of the trials that attempt to address any particular research question. However, certain limitations always warrant caution when interpreting the results of systematic reviews. If the quality of the studies addressing the research question is poor, the level of evidence produced by them would be low. Systematic reviews must critically assess the quality of evidence, as this directly affects the extent of our confidence that the estimates of the effect are correct.7 Apart from the quality of the included trials, heterogeneity of the trials always creates a challenge.8 Differences in study population, study settings, and details of the study design (e.g., inclusion/exclusion criteria) could make comparison of the trials very difficult. US research in particular is subject to additional sources of heterogeneity. Point-of-care US consists of two primary components: image acquisition (procedural skill) and image interpretation (pattern recognition). In image acquisition, operator experience, lack of standardization of scanning protocols, use of varied US machines and probes, and different patient position during US imaging contributes to the heterogeneity of research methods. These issues are well highlighted in the systematic review by Al Deeb et al.2 In image interpretation, variations in diagnostic criteria and operator dependence can influence results of findings. In the studies included in this systematic review the diagnostic criteria for B-lines were different (Volpicelli, Comet score, and Lichtenstein methods), and the interobserver reliability for visualizing B-lines by operators was not measured in most of the included trials.2 These factors contribute to increased risk of bias in studies and reduced generalizability of the results. As consumers of evidence, a clinician-reader of a systematic review must carefully judge both reported study quality and outcome effect, to determine if practice change is warranted.8 From the perspective of further investigation, a natural next step would be to standardize scanning protocols and further limit heterogeneity among various studies by creating clear training guidelines for the operators acquiring and interpreting the images. Finally, once diagnostic parameters are better defined, research can progress to assessing more patient-oriented outcomes, effects on decision-making, and cost-effective analyses. Improvement in quality of US research in the past decade promises more and more high-quality trials and higher levels of evidence in the near future. Such trials could pave way for higher-quality systemic reviews, meta-analyses, and clinical guidelines and ultimately result in translating more high-level evidence into clinical practice (i.e., knowledge translation). Application of De Bono’s principles of the Six Thinking Hats provides a framework for analysis of US research and systematic reviews produced based on these trials. Readers are encouraged to pay special attention to the quality of the trials included in systematic reviews and the existing heterogeneity among the trials. This critical approach could help clinicians safely and expertly incorporate the evidence
921
produced by these trials and systematic reviews into clinical practice. As Edward de Bono once stated, “An expert is someone who has succeeded in making decisions and judgments simpler through knowing what to pay attention to and what to ignore.”1 Yiju T. Liu, MD Kaiser Permanente Mid Atlantic Rockville, MD Shahriar Zehtabchi, MD ([email protected]) Department of Emergency Medicine State University of New York Downstate Medical Center Brooklyn, NY Andrew S. Liteplo, MD Department of Emergency Medicine Massachusetts General Hospital Harvard Medical School Boston, MA
Supervising Editor: David C. Cone, MD.
References 1. De Bono E. Six Thinking Hats: An Essential Approach to Business Management. New York, NY: Little Brown and Company, 1985. 2. Al Deeb M, Barbic S, Featherstone R, Dankoff J, Barbic D. Point-of-care ultrasonography for the diagnosis of acute cardiogenic pulmonary edema in patients presenting with acute dyspnea: a systematic review and meta-analysis. Acad Emerg Med 2014;21:844– 852. 3. American College of Emergency Physicians. Emergency Ultrasound Guidelines. Available at: http:// www.acep.org/Clinical—Practice-Management/Ultra sound. Accessed May 25, 2014. 4. Accreditation Council for Graduate Medical Education. Emergency Medicine Guidelines. Available at: http://dconnect.acgme.org/acWebsite/RRC_110/110_ guidelines.asp. Accessed May 25, 2014. 5. Jang TB, Coates WC, Liu YT. The competency-based mandate for emergency bedside sonography training and a tale of two residency programs. J Ultrasound Med 2012;31:515–21. 6. Zehtabchi S, Kline JA. The art and science of probabilistic decision-making in emergency medicine. Acad Emerg Med 2010;17:521–3. € nemann HJ, et al. 7. Balshem H, Helfand M, Schu GRADE guidelines: 3. Rating the quality of evidence. J Clin Epidemiol 2011;64:401–6. 8. Guyatt GH, Oxman AD, Kunz R, et al. GRADE guidelines: 7. Rating the quality of evidence–inconsistency. J Clin Epidemiol 2011;64:1294–302.
