To Örebro University

INTRODUCTION: Damage to the thoracic cage is common in the injured patient, both when the injuries are confined to this single cavity and as part of the overall injury burden of a polytraumatized patient. In a subset of these patients, the severity of injury to the intrathoracic viscera is either underappreciated at admission or blossom over the following 48-72 h. The ability to promptly identify these patients and abrogate complications therefore requires triage of such at-risk patients to close monitoring in a critical care environment. At our institution, this triage hinges on the Pain, Inspiratory effort, Cough (PIC) score, which generates a composite unitless score from a nomogram which aggregates several variables-patient-reported Pain visual analog scale, Incentive spirometry effort, and the perceived adequacy of Cough. We thus sought to audit PIC's discriminant power in predicting intensive care unit (ICU) need.

METHODS: This retrospective cohort study was performed at an urban, academic, level 1 trauma center. All isolated chest wall injuries (excluded any Abbreviated Injury Score >2 in head or abdomen) from January 2020 to June 2021 were identified in the local trauma registry. The electronic medical record was queried for standard demographics, admission PIC score, postadmission destination, ICU and hospital length of stay (LOS), and any unplanned admissions to the ICU. Chi-squared tests were used to determine differences between PIC score outcomes and the recursive partitioning method correlated admission PIC score to ICU LOS.

RESULTS: Two hundred and thirty six isolated chest wall injury patients were identified, of whom 194 were included in the final analysis. The median age was 60 (interquartile range [IQR] 50-74) years, 63.1% were male, and the median (IQR) number of rib fractures was 3.0 (2.0-5.0). A cutoff PIC score of 7 or lower was associated with ICU admission (odds ratio [OR] 95% CI: 8.19 [3.39-22.55], P < 0.001 with a PPV = 41.4%, NPV = 91%), and with ICU admission for greater than 48 h [OR (95% CI): 26.86 (5.5-43.96), P < 0.001, with a PPV = 25.9%, NPV = 98.7%] but not anatomic injury severity score, hospital LOS or ICU, or the requirement for mechanical ventilation. The association between PIC score 7 or below and the presence of bilateral fractures, flail chest, or sternal fracture did not meet statistical significance. The accurate cut point of the PIC score to predict ICU admission over 48 h in our retrospective cohort was calculated as PIC ≤ 7 for P = 0.013 and PIC ≤ 6 for P = 0.001.

CONCLUSIONS: Patients with isolated chest wall injuries require effective reproducible triage for ICU-level care. The PIC score appears to be a moderate discriminator of critical care need, per se, as judged by our recorded complication rate requiring critical care intervention. This vigilance may pay dividends in early detection and abrogation of respiratory failure emergencies. Furthermore, PIC score delineation for ICU need appears to be appropriate at 7 or less; this threshold can be used during admission triage to guide care.