Search

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.

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.

Context Dyspnea is an uncomfortable and distressing sensation experienced by hospitalized patients. Objectives There is no large-scale study of the prevalence and intensity of patient-reported dyspnea at the time of admission to the hospital. Methods Between March 2014 and September 2016, we conducted a prospective cohort study among all consecutive hospitalized patients at a single tertiary care center in Boston, MA. During the first 12 hours of admission to medical-surgical and obstetric units, nurses at our institution routinely collect a patient's 1) current level of dyspnea on a 0–10 scale with 10 anchored at "unbearable," 2) worst dyspnea in the past 24 hours before arrival at the hospital on the same 0–10 scale, and 3) activities that were associated with dyspnea before admission. The prevalence of dyspnea was identified, and tests of difference were performed across patient characteristics. Results We analyzed 67,362 patients, 12% of whom were obstetric patients. Fifty percent of patients were admitted to a medical-surgical unit after treatment in the emergency department. Among all noncritically ill inpatients, 16% of patients experienced dyspnea in the 24 hours before the admission. Twenty-three percent of patients admitted through the emergency department reported any dyspnea in the past 24 hours. Eleven percent experienced some current dyspnea when interviewed within 12 hours of admission with 4% of patients experiencing dyspnea that was rated 4 or greater. Dyspnea of 4 or more was present in 43% of patients admitted with respiratory diagnoses and 25% of patients with cardiovascular diagnoses. After multivariable adjustment for severity of illness and patient comorbidities, patients admitted on the weekend or during the overnight nursing shift were more likely to report dyspnea on admission. Conclusion Dyspnea is a common symptom among all hospitalized patients. Routine documentation of dyspnea is feasible in a large tertiary care center.

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.

We tested whether subjects could detect and localize inflation confined to a single lung lobe. A balloon-sealed catheter was placed into a lobar bronchus of unsedated subjects via fiberoptic bronchoscopy. Topical anesthesia (lidocaine) was used to suppress cough and irritation associated with inflation of the sealing balloon. Small (45–60 ml) or large (100–240 ml) stimulus volumes were insufflated via the catheter. In a forced-choice protocol, subjects were readily able to detect large inflations and correctly identify the side on which the stimulus was given, but small inflations were at the threshold of detection and were not correctly localized. Additional lidocaine applied to the bronchus in two subjects did not degrade detection. Circumstantial evidence suggests that the sensation arose in the lung. We conclude that this technique is feasible for the study of pulmonary perception.

Unlike individuals with comparable degrees of respiratory muscle weakness from other causes, quadriplegic patients have a blunted ventilatory and P0.1 response to hypercapnia. This suggests that the diminished response in quadriplegia is due, in part, to an alteration in respiratory drive. We measured the hypercapnic response in 9 subjects with chronic quadriplegia (Q) and 8 normal controls (N). Ventilatory muscle strength, maximum voluntary ventilation (MVV), and lung volumes were measured in all subjects. The ventilatory response (HCVR) in Q was significantly less than in N (0.73 ± 0.37 vs 2.95 ± 0.4 L·min −1 · mmHg −1 ; P , even when normalized for indices of respiratory muscle performance (e.g., vital capacity, MVV). There was no significant change in the HCVR in Q after the administration of naloxone. We also serially studied 2 subjects with acute quadriplegia, and found that despite progressive improvement in respiratory muscle performance, there was no accompanying increase in the response to hypercapnia. These data suggest that muscle weakness alone cannot explain the blunted hypercapnic response in quadriplegia, and are consistent with the hypothesis that these subjects have a reduced ventilatory drive.

In a Dutch birth cohort study published in this issue of the Journal, children had an increased risk of bronchial hyperresponsiveness or dyspnea at age 8 years if they had a high body mass index (BMI) at 6 to 7 years of age with or without increased BMI at an earlier age. Taking advantage of the longitudinal nature of their study of 3,756 children, the authors also report the encouraging finding that children who had a high BMI at a young age but whose BMI returned to normal did not have increased risk either of bronchial hyperresponsiveness or dyspnea. As always, extrapolation from an observational study to early-life interventions should be done cautiously. It is not known whether children whose BMI decreases without any known deliberate intervention are the subset of children who might benefit from BMI screening or from weight-reduction programs. Programs for screening and early intervention in obesity abound, but further prospective evaluation of their success in reducing weight and obesity-associated respiratory symptoms is needed. But what does overweight-associated dyspnea signify in the children from this birth cohort, and is dyspnea a symptom of asthma, as the investigators suggest? Mouse model data suggest that obesity can lead to bronchial hyperresponsiveness. Airway narrowing can occur through obesity-associated lung and tidal volume reduction, low-grade systemic inflammation, or obesity-related changes in adipose-derived hormones, including leptin and adiponectin. Nevertheless, studies of adults in which data suggest that asthma might be overdiagnosed in obese adults with dyspnea are accumulating. Misdiagnosis of asthma can result in inappropriate prescription of short-acting bronchodilators or corticosteroids in persons who are short of breath for obesity-related dyspnea that does not represent reversible airway obstruction. In a study of 16,171 participants ( 17 years of age) from the Third National Health and Nutrition Examination Survey, the highest BMI quintile (ie, the most obese participants) was associated with the greatest risk of self-reported asthma, bronchodilator use, and dyspnea with exertion (odds ratio, 2.66; 95% CI, 2.35-3.00). The highest BMI quintile, however, had the lowest risk for significant airflow