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Dyspnea is an uncomfortable sensation with the potential to cause psychological trauma. Patients presenting with acute respiratory failure, particularly when tidal volume is restricted during mechanical ventilation, may experience the most distressing form of dyspnea known as air hunger. Air hunger activates brain pathways known to be involved in posttraumatic stress disorder (PTSD), anxiety, and depression. These conditions are considered part of the post-intensive care syndrome. These sequelae may be even more prevalent among patients with ARDS. Low tidal volume, a mainstay of modern therapy for ARDS, is difficult to avoid and is likely to cause air hunger despite sedation. Adjunctive neuromuscular blockade does not prevent or relieve air hunger, but it does prevent the patient from communicating discomfort to caregivers. Consequently, paralysis may also contribute to the development of PTSD. Although research has identified post-ARDS PTSD as a cause for concern, and investigators have taken steps to quantify the burden of disease, there is little information to guide mechanical ventilation strategies designed to reduce its occurrence. We suggest such efforts will be more successful if they are directed at the known mechanisms of air hunger. Investigation of the antidyspnea effects of sedative and analgesic drugs commonly used in the ICU and their impact on post-ARDS PTSD symptoms is a logical next step. Although in practice we often accept negative consequences of life-saving therapies as unavoidable, we must understand the negative sequelae of our therapies and work to minimize them under our primary directive to "first, do no harm" to patients.

Teaching clinical reasoning is challenging, particularly in the time-pressured and complicated environment of the ICU. Clinical reasoning is a complex process in which one identifies and prioritizes pertinent clinical data to develop a hypothesis and a plan to confirm or refute that hypothesis. Clinical reasoning is related to and dependent on critical thinking skills, which are defined as one's capacity to engage in higher cognitive skills such as analysis, synthesis, and self-reflection. This article reviews how an understanding of the cognitive psychological principles that contribute to effective clinical reasoning has led to strategies for teaching clinical reasoning in the ICU. With familiarity with System 1 and System 2 thinking, which represent intuitive vs analytical cognitive processing pathways, respectively, the clinical teacher can use this framework to identify cognitive patterns in clinical reasoning. In addition, the article describes how internal and external factors in the clinical environment can affect students' and trainees' clinical reasoning abilities, as well as their capacity to understand and incorporate strategies for effective critical thinking into their practice. Utilizing applicable cognitive psychological theory, the relevant literature on teaching clinical reasoning is reviewed, and specific strategies to effectively teach clinical reasoning and critical thinking in the ICU and other clinical settings are provided. Definitions, operational descriptions, and justifications for a variety of teaching interventions are discussed, including the "one-minute preceptor" model, the use of concept or mechanism maps, and cognitive de-biasing strategies.

Dyspnea is an uncomfortable sensation with the potential to cause psychological trauma. Patients presenting with acute respiratory failure, particularly when tidal volume is restricted during mechanical ventilation, may experience the most distressing form of dyspnea known as air hunger. Air hunger activates brain pathways known to be involved in posttraumatic stress disorder (PTSD), anxiety, and depression. These conditions are considered part of the post-intensive care syndrome. These sequelae may be even more prevalent among patients with ARDS. Low tidal volume, a mainstay of modern therapy for ARDS, is difficult to avoid and is likely to cause air hunger despite sedation. Adjunctive neuromuscular blockade does not prevent or relieve air hunger, but it does prevent the patient from communicating discomfort to caregivers. Consequently, paralysis may also contribute to the development of PTSD. Although research has identified post-ARDS PTSD as a cause for concern, and investigators have taken steps to quantify the burden of disease, there is little information to guide mechanical ventilation strategies designed to reduce its occurrence. We suggest such efforts will be more successful if they are directed at the known mechanisms of air hunger. Investigation of the antidyspnea effects of sedative and analgesic drugs commonly used in the ICU and their impact on post-ARDS PTSD symptoms is a logical next step. Although in practice we often accept negative consequences of life-saving therapies as unavoidable, we must understand the negative sequelae of our therapies and work to minimize them under our primary directive to "first, do no harm" to patients.

Background In adult patients, the consistent use of language to describe dyspnea enhances patient-provider communication and contributes to diagnostic and therapeutic decisions. The objective of this research was to determine whether pediatric patients similarly display consistency in the language used to describe "uncomfortable awareness of breathing." Methods One hundred children between the ages of 8 and 15 years with moderate to severe persistent asthma enrolled in an asthma education research program completed questionnaires regarding descriptors of asthma on each of two occasions. In addition to the breathlessness questionnaires, demographic information, self-reported asthma severity, ED visits, missed school days, anthropometrics, and spirometry were obtained for each participant. Results Children were reliable in their choice of the descriptors that they applied to their breathing discomfort across two occasions, and they selected the same descriptors that were used by adults with asthma in previous studies. Children with greater self-reported asthma severity endorsed more descriptors to characterize breathing discomfort than did children with less severe asthma, but no differences were found among children based on demographic or anthropometric variables. Conclusions Children with moderate to severe persistent asthma are reliable in their choice of descriptors of breathlessness. Knowledge of their experience of symptoms may be helpful clinically in the assessment and management of asthma.

Study objectives We tested the hypothesis thatdescriptors of breathlessness represent distinct and separablecognitive constructs, and predicted that the use of descriptors ofbreathlessness by healthy individuals is the same as their use bypatients with cardiopulmonary disease. Design Clusteranalyses obtained in healthy individuals were compared with thoseobtained previously in patients who complained of breathing discomfort. In addition, we used multidimensional scaling (MDS) techniques toanalyze relationships among descriptors in healthy individuals. Setting Public university. Participants The participants were 100 healthy individuals (48 men and 52 women)ranging in age between 18 and 65 years (mean, 27.9 ± 11.7 years). Measurements and results Participants judgedthe dissimilarity among pairs of 15 descriptors of breathlessness thatwere used previously to examine the experience of dyspnea in patientswho complained of breathing discomfort. Cluster analysis solutionsobtained in the healthy individuals were virtually identical to thoseobtained previously in patients. Three dimensions (attributes) ofbreathing discomfort were uncovered with MDS: "Depth and frequency ofbreathing," "Perceived need, or urge, to breathe," and "Difficulty breathing and phase of respiration." The results didnot depend on age, sex, levels of education, or the presence ofuncomfortable awareness of breathing with activities. Conclusions The relations among descriptors ofbreathlessness obtained in healthy individuals support the contentionthat the association of different clusters with different diseasestates reflects distinct and separable cognitive constructs that are not simply dependent on the presence of an underlying pathophysiologyor on a specific disease condition. Our results in healthy individualsalso suggest that distinct qualities of breathlessness relate todifferent physiologic mechanisms underlying respiratorydiscomfort.

(CHEST 2009; 135:201–209) Editor’s note: In this series, interactive diagrams are an important part of each article and are referred to throughout. You can access these diagrams online at www.chestjournal.org/content/135/1/201.full. Included with the diagrams are “Show Me” videos, animated narrations that walk you through the main points of each diagram. The first time you access the online material, you may be asked to update your Web browser’s Flash Player plugin; this will enable you to view the diagrams as intended. If you are not automatically prompted to update the plugin and you have any problems using the diagrams, you can download the latest version of the Flash Player by visiting http://www.adobe.com/go/getflash.

Study objectives: To determine whether there is any difference in diagnostic, therapeutic, and outcome efficacy between protocols utilizing daily ( ie , routine) chest radiographs (CXRs) and those utilizing clinically indicated ( ie , nonroutine) CXRs in mechanically ventilated patients. Design: Prospective, randomized, observational study. Setting: A 20-bed medical ICU at a university hospital. Patients: Adult patients who had been receiving mechanical ventilation for > 48 h. Interventions: None. Measurements and results: Ninety-four patients who had been intubated for at least 48 h were randomized to receive either routine or nonroutine CXRs and were observed until extubation or death. The percentage of CXRs with new findings was significantly larger in the nonroutine CXR group (53.1%; 120 CXRs) compared to that in the routine CXR group (33.4%; 98 CXRs; odds ratio [OR], 1.59; 95% confidence interval [CI], 1.16 to 2.18; p=0.004). The number of CXRs with new findings that resulted in interventions was significantly larger in the nonroutine CXR group (26.5%; 60 CXRs) compared to that in the routine CXR group (13.3%; 39 CXRs; OR, 2.0; 95% CI, 1.29 to 3.08; p=0.002). There was no difference in the mean duration of mechanical ventilation (routine CXR arm, 7.93 days; nonroutine CXR arm, 6.76 days; p=0.2606), length of ICU stay (routine CXR arm, 11.93 days; nonroutine CXR arm, 9.55 days; p=0.1936), and total length of hospital stay (routine CXR arm, 19.34 days; nonroutine CXR arm, 16.45 days; p=0.2199) between the two groups. Although patients in the nonroutine arm of the study received fewer CXRs, adverse outcomes ( eg , length of mechanical ventilation, length of hospital stay, length of ICU stay, and mortality) did not increase (p = 0.818). Using the number of CXRs per patient as a surrogate, there was a statistically significant cost savings and decreased radiation exposure in the nonroutine CXR group. Conclusions: For mechanically ventilated patients, a strategy calling for daily routine CXRs compared to CXRs obtained based on clinical indications alone was not associated with reduced ICU or hospital length of stay or with reduced mortality.