Magnitude of rib fracture displacement predicts opioid requirements

INTRODUCTION It is unknown whether the magnitude of rib fracture (RF) displacement predicts pain medication requirements in blunt chest trauma patients. METHODS Adult blunt RF patients undergoing computed tomography (CT) of the chest admitted to an urban Level 1 trauma center (2007-2012) were retrospectively reviewed. Pain management in those with displaced RF (DRF), nondisplaced RF (NDRF), or combined DRF and NDRF (CRF) was compared by univariate analysis. Linear regression models were developed to determine whether total opioid requirements [expressed as log morphine equianalgesic dose (MED)] could be predicted by the magnitude of RF displacement (expressed as the sum of the Euclidean distance of all displaced RF) or number of RF, after adjusting for patient and injury characteristics. RESULTS There were 245 patients, of whom 39 (16%) had DRF only, 77 (31%) had NDRF only, and 129 (53%) had CRF. Opioids were given to 224 patients (91%). Compared to DRF (mean, 1.7 RF per patient) and NDRF patients (2.4 RF per patient), those with CRF (6.8 RF per patient) were older and had more RF per patient and a higher Injury Severity Score (ISS) and MED (251 vs 53 and 105 mg, respectively, p < 0.0001 and p = 0.0045). They also more frequently received patient-controlled analgesia. Patients with displaced RF had a lower mean ISS and MED and received more epidural analgesia compared with patients with NDRF. Total MED was associated with both the magnitude of RF displacement (p < 0.0001) and the number of RF (p < 0.0001). Every 5-mm increase in total displacement predicted a 6.3% increase in mean MED (p = 0.0035), while every additional RF predicted an 11.2% increase in MED (p = 0.0001). These associations included adjustment for age, ISS, and presence of chest tubes. CONCLUSION The magnitude of RF displacement and the number of RF predicted opioid requirements. This information may assist in anticipating patients with blunt RF who might have higher analgesic requirements. LEVEL OF EVIDENCE Therapeutic study, level IV.