Half-a-dozen ribs: the breakpoint for mortality.

Background: We hypothesized that the number of rib fractures independently impacted patient pulmonary morbidity and mortality.

Methods: The National Trauma Data Bank (NTDB, v. 3.0 American College of Surgeons, Chicago, IL) was queried for patients sustaining 1 or more rib fractures. Data abstracted included the number of rib fractures by International Classification of Diseases-9 code, Injury Severity Score, the occurrence of pneumonia, acute respiratory distress syndrome, pulmonary embolus, pneumothorax, aspiration pneumonia, empyema, and associated injuries by abbreviated injury score, the need for mechanical ventilation, number of ventilator days, intensive care unit (ICU) length of stay (LOS), hospital LOS, mortality, and use of epidural analgesia. Statistical analysis was performed using the Student t test and linear regression analysis. Statistical significance was defined as a P value of less than .05.

Results: The NTDB included 731,823 patients. Of these, 64,750 (9%) had a diagnosis of 1 or more fractured ribs. Thirteen percent (n = 8,473) of those with rib fractures developed 13,086 complications, of which 6,292 (48%) were related to a chest-wall injury. Mechanical ventilation was required in 60% of patients for an average of 13 days. Hospital LOS averaged 7 days and ICU LOS averaged 4 days. The overall mortality rate for patients with rib fractures was 10%. The mortality rate increased (P < .02) for each additional rib fracture. The same pattern was seen for the following morbidities: pneumonia (P < .01), acute respiratory distress syndrome (P < .01), pneumothorax (P < .01), aspiration pneumonia (P < .01), empyema (P < .04), ICU LOS (P < .01), and hospital LOS for up to 7 rib fractures (P < .01). An association between increasing hospital LOS and number of rib fractures was not shown (P = .19). Pulmonary embolism also was not related to the number of rib fractures (P = .06). Epidural analgesia was used in 2.2% (n = 1,295) of patients with rib fractures. A reduction in mortality with epidural analgesia was shown at 2, 4, and 6 through 8 rib fractures. The use of epidural analgesia had no impact on the frequency of pulmonary complications. When stratifying data by Injury Severity Score and the presence or absence of rib fractures the mortality rates were similar.

Conclusions: Increasing the number of rib fractures correlated directly with increasing pulmonary morbidity and mortality. Patients sustaining fractures of 6 or more ribs are at significant risk for death from causes unrelated to the rib fractures. Epidural analgesia was associated with a reduction in mortality for all patients sustaining rib fractures, particularly those with more than 4 fractures, but this modality of treatment appears to be underused.