The Sequential Clinical Assessment of Respiratory Function (SCARF) score: A dynamic pulmonary physiologic score that predicts adverse outcomes in critically ill rib fracture patients

Abstract

Background: Rib fracture scoring systems are limited by a lack of serial pulmonary physiologic variables. We created the Sequential Clinical Assessment of Respiratory Function (SCARF) score and hypothesized that admission, maximum, and rising scores predict adverse outcomes among critically ill rib fracture patients.

Methods: Prospective cohort study of rib fracture patients admitted to the surgical intensive care unit (ICU) at a Level I trauma center from August 2017 to June 2018. The SCARF score was developed a priori and validated using the cohort. One point was assigned for: <50% predicted, respiratory rate >20, numeric pain score ≥5, and inadequate cough. Demographics, injury patterns, analgesics, and adverse pulmonary outcomes were abstracted. Performance characteristics of the score were assessed using the receiver operator curve area under the curve.

Results: Three hundred forty scores were available from 100 patients. Median admission and maximum SCARF score was 2 (range 0-4). Likelihood of pneumonia (p = 0.04), high oxygen requirement (p < 0.01), and prolonged ICU length of stay (p < 0.01) were significantly associated with admission and maximum scores. The receiver operator curve area under the curve for the maximum SCARF score for these outcomes were 0.86, 0.76, and 0.79, respectively. In 10 patients, the SCARF score worsened from admission to day 2; these patients demonstrated increased likelihood of pneumonia (p = 0.04) and prolonged ICU length of stay (p = 0.07). Patients who developed complications maintained a SCARF score one point higher throughout ICU stay compared with patients who did not (p = 0.04). The SCARF score was significantly associated with both narcotic (p = 0.03) and locoregional anesthesia (p = 0.03) usage.

Conclusion: Admission, maximum, daily, and rising scores were associated with utilization of pain control therapies and development of adverse outcomes. The SCARF score may be used to guide therapies for critically ill rib fracture patients, with a proposed threshold greater than 2.

Level of evidence: Prognostic study, level II.