Management of Refractory Breathlessness: a Review for General Internists

Reliability, Validity, and Responsiveness of the DEG, a Three-Item Dyspnea Measure

BACKGROUND

Dyspnea is a common and debilitating symptom that affects many different patient populations. Dyspnea measures should assess multiple domains.

OBJECTIVE

To evaluate the reliability, validity, and responsiveness of an ultra-brief, multi-dimensional dyspnea measure.

DESIGN

We adapted the DEG from the PEG, a valid 3-item pain measure, to assess average dyspnea intensity (D), interference with enjoyment of life (E), and dyspnea burden with general activity (G).

PARTICIPANTS

We used data from a multi-site randomized clinical trial among outpatients with heart failure.

MAIN MEASURES

We evaluated reliability (Cronbach's alpha), concurrent validity with the Memorial-Symptom-Assessment-Scale (MSAS) shortness-of-breath distress-orbothersome item and 7-item Generalized-Anxiety-Disorder (GAD-7) scale, knowngroups validity with New-York-Heart-Association-Functional-Classification (NYHA) 1-2 or 3-4 and presence or absence of comorbid chronic obstructive pulmonary disease (COPD), responsiveness with the MSAS item as an anchor, and calculated a minimal clinically important difference (MCID) using distribution methods.

KEY RESULTS

Among 312 participants, the DEG was reliable (Cronbach's alpha 0.92). The mean (standard deviation) DEG score was 5.26 (2.36) (range 0-10) points. DEG scores correlated strongly with the MSAS shortness of breath distress-or-bothersome item (r=0.66) and moderately with GAD-7 categories (ρ=0.36). DEG scores were statistically significantly lower among patients with NYHA 1-2 compared to 3-4 [mean difference (standard error): 1.22 (0.27) points, p<0.01], and those without compared to with comorbid COPD [0.87 (0.27) points, p<0.01]. The DEG was highly sensitive to change, with MCID of 0.59-1.34 points, or 11-25% change.

CONCLUSIONS

The novel, ultra-brief DEG measure is reliable, valid, and highly responsive. Future studies should evaluate the DEG's sensitivity to interventions, use anchor-based methods to triangulate MCID estimates, and determine its prognostic usefulness among patients with chronic cardiopulmonary and other diseases.

Pathophysiology and clinical evaluation of the patient with unexplained persistent dyspnea

INTRODUCTION

Dyspnea is a complex symptom, which largely results from an imbalance between an afferent sensory stimulus and the corresponding efferent respiratory neuromuscular response. In addition, it is heavily influenced by the patient's prior experiences and sociocultural factors.

AREAS COVERED

The diagnostic approach to these patients requires a graded, systematic, and often multidisciplinary approach to determine what is the underlying pathophysiologic process. Utilization of objective data obtained through lab testing, imaging, and advanced testing, such as cardiopulmonary exercise testing, is often required to help identify underlying pathology contributing to a patient's symptoms. This article will review dyspnea's underlying pathophysiological mechanisms and standardized approaches to diagnoses. In the expert opinion section, we will discuss our own clinical approach to evaluating patients with persistent dyspnea.

EXPERT OPINION

Unexplained dyspnea is a challenging diagnosis that occurs in patients with and without underlying cardiopulmonary diseases. It requires a systematic approach, which initially uses clinical evaluation in addition to standard imaging and clinical biomarkers. When diagnoses are not made during the initial evaluation, subsequent tests can include cardiopulmonary exercise test and methacholine challenge. To be certain of the correct diagnosis, It is imperative that the clinician determines dyspnea's response to a particular therapeutic intervention.

Nasal high flow oxygen therapy during acute admissions or periods of worsening symptoms

PURPOSE OF REVIEW

Nasal high flow therapy (NHF) is increasingly used in acute care settings. In this review, we consider recent advances in the utilization of NHF in chronic obstructive pulmonary disease (COPD), terminal cancer and symptom management. Considerations around NHF use during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic are also discussed.

RECENT FINDINGS

NHF enables humidification and high flows to be provided together with titrated, supplemental oxygen therapy. Compared to conventional oxygen therapy, NHF improves respiratory physiology by reducing workload, enhancing muco-ciliary clearance and improving dead space washout. Some studies suggest that early use of NHF in people being cared for in the emergency department leads to lower rates of invasive ventilation and noninvasive ventilation. There is also emerging evidence for NHF use in people with COPD and chronic respiratory failure, and in palliative care. NHF is comfortable, well-tolerated and safe for use in the management of breathlessness in people with cancer. NHF can be delivered by face mask to patients with SARS-CoV-2 infection, to ease the burden on critical care resources.

SUMMARY

The evidence base for NHF is rapidly growing and offers promise in relieving troublesome symptoms and for people receiving palliative care.