When to Use
The Respiratory Distress Observation Scale (RDOS) can be used to assess dyspnea in palliative care and/or intensive care unit (ICU) patients who are unable to self-report symptoms.
Pearls/Pitfalls
Pearls
Observer training improves reliability: Interrater reliability of RDOS improves when staff receive structured training on identifying behavioral and respiratory signs of distress. Institutions implementing RDOS should include standardized observer education.
Useful for tracking response to therapy: Serial RDOS assessments can help monitor response to interventions (e.g., opioids, anxiolytics, oxygen), offering a practical tool for evaluating symptom trajectory.
Complementary to physiologic monitoring: RDOS can supplement vital signs and oxygen saturation, helping clinicians identify distress earlier, especially when physiologic measures appear stable.
Pitfalls
Although RDOS is inversely correlated with oxygen saturation, no RDOS cutoff has been developed for providing supplemental oxygen.
RDOS should not be used in patients who are paralyzed due to either neuromuscular blocking agents or neuromuscular disease.
Data is limited on the performance of RDOS in non-communicative patients, as initial validation studies were carried out primarily utilizing patients with sufficient cognition to provide self-reports of dyspnea; recent modified versions of RDOS have shown correlation with dyspnea surrogates in this patient population.
Limited external validation: Most validation studies have been small, single-center, and conducted in palliative settings. Therefore, generalizability to diverse ICU populations remains uncertain.
Potential for confounding by sedation or delirium: Sedative or antipsychotic use may blunt observable behaviors (e.g., facial expression, restlessness), leading to falsely low scores.
Not a diagnostic tool: High RDOS suggests respiratory distress but does not differentiate between etiologies such as hypoxia, hypercapnia, or anxiety; it should always be interpreted within clinical context.
Why Use
RDOS inputs are easily observable and can provide clinicians information on the respiratory status of patients. RDOS is correlated with dyspnea but not pain, allowing clinicians to distinguish between two common causes of discomfort.
Advice
While high RDOS scores should prompt consideration of treatment for dyspnea, RDOS does not help to identify a cause of dyspnea. Keep a wide differential diagnosis and consider other reversible etiologies prior to palliative interventions.
Management
RDOS is an eight-variable scale with scores ranging from 0 to 16. The optimal cutoff point has not been definitively set, but the most recent validation study found RDOS ≥ 4 performed best in identifying patients with moderate to severe dyspnea.
Critical Actions
Consider palliative treatments to support work of breathing and patient comfort in patients with RDOS ≥ 4, such as pain medication and/or supplemental oxygen.
Evidence Appraisal
The original study proposing a seven-variable version RDOS utilized a 210-subject convenience sample of pulmonary rehabilitation and postoperative pain patients as well as healthy volunteers to establish the construct and discriminant validity of the scale compared to self-reports of dyspnea and pain. An eighth variable, paradoxical breathing, was added prior to the second validation study conducted by the original creator, which examined 99 palliative care patients with lung pathology such as COPD, pneumonia, congestive heart failure (CHF), or lung cancer. This study showed a positive correlation between RDOS and self-reported dyspnea and an inverse correlation between RDOS and oxygen saturation. A cutoff of ≥ 3 was originally proposed for identifying moderate to severe dyspnea as measured by self-report. A subsequent validation study of 122 palliative care patients in Singapore tested multiple cutoffs ranging from 2 to 5 for moderate to severe dyspnea, and found that a cutoff of ≥ 4 had improved test characteristics for identifying this group of patients. A Japanese version of RDOS was also validated in the ICU setting with 128 patients. No studies to date have assessed for RDOS cutoffs to predict intervenable sequalae of moderate to severe dyspnea, such as hypoxemia. As such, RDOS may be a tool for guiding symptom management rather than one proven to improve patient-centered outcomes.
The studies above have relatively small sample sizes and wide heterogeneity in patient populations, ranging from the ICU to outpatient pulmonary rehabilitation patients. Physiological responses to pulmonary interventions may differ significantly between these groups. Further validation is needed in each of these populations.
Potential cultural or linguistic biases were partially accounted for when translating the RDOS, but the Japanese study required re-translation of three items on the scale, underscoring the difficulty of accurate translation in this context.
Modifications to better adapt the RDOS scale for ICU patients include the intensive care RDOS (IC-RDOS) and mechanical ventilation RDOS (MV-RDOS), both five-variable scales. The MV-RDOS has the most robust validation in both communicative and non-communicative patients, demonstrating positive correlations with both self-reported dyspnea and inspiratory EMG activity.
Facts and Figures
RDOS Score Cutoffs to Identify Patients with Moderate and Severe Dyspnea (from Zhuang et al):
References
Original/Primary
URL: https://pubmed.ncbi.nlm.nih.gov/18370892/
Campbell ML. Psychometric testing of a respiratory distress observation scale. J Palliat Med. 2008;11(1):44-50. doi:10.1089/jpm.2007.0090
Validation
URL: https://pubmed.ncbi.nlm.nih.gov/20078243/
Campbell ML, Templin T, Walch J. A Respiratory Distress Observation Scale for Patients Unable to Self-Report Dyspnea. J Palliat Med. 2010;13(3):285-290. doi:10.1089/jpm.2009.0229
URL: https://pubmed.ncbi.nlm.nih.gov/25634631/
Campbell ML, Templin T. Intensity cut-points for the Respiratory Distress Observation Scale. Palliat Med. 2015;29(5):436-442. doi:10.1177/0269216314564238
URL: https://pubmed.ncbi.nlm.nih.gov/30391404/
Zhuang Q, Yang GM, Neo SH, Cheung YB. Validity, reliability, and diagnostic accuracy of the Respiratory Distress Observation Scale for assessment of dyspnea in adult palliative care patients. J Pain Symptom Manage. 2019;57(2):304-310. doi:10.1016/j.jpainsymman.2018.10.506
Other References (including meta-analyses, CPGs, and impact analyses)
URL: https://pubmed.ncbi.nlm.nih.gov/34379672/
Sakuramoto H, Hatozaki C, Unoki T, Aikawa G, Kobayashi S, Okamoto S, Shimomura S, Kawasaki A, Fukui M. Translation, reliability, and validity of Japanese version of the Respiratory Distress Observation Scale. PLoS One. 2021;16(8):e0255991. doi:10.1371/journal.pone.0255991
URL: https://pubmed.ncbi.nlm.nih.gov/36973007/
Decaève M, Bureau C, Campion S, Niérat MC, Rivals I, Wattiez N, Faure M, Mayaux J, Morawiec E, Raux M, Similowski T, Demoule A. Interventions relieving dyspnea in intubated patients show responsiveness of the mechanical ventilation-respiratory distress observation scale. Am J Respir Crit Care Med. 2023;208(1):39-48. doi:10.1164/rccm.202301-0188OC
URL: https://pubmed.ncbi.nlm.nih.gov/26259140/
Persichini R, Gay F, Schmidt M, Mayaux J, Demoule A, Morélot-Panzini C, Similowski T. Diagnostic Accuracy of Respiratory Distress Observation Scales as Surrogates of Dyspnea Self-report in Intensive Care Unit Patients. Anesthesiology. 2015;123(4):830-837. doi:10.1097/ALN.0000000000000805