This study aimed to investigate the PVF according to different types of rib fractures and pain levels. The results strongly suggest that when the total number of fractured ribs is ≥ 5, there are ≥ 5 breakpoints, or NRS is ≥ 7, the VC, FEV1, and PEF are more affected. Nevertheless, the patients with rib fractures will present a wide variety of conditions, and identifying those at higher risk of altered PVF could be useful for triage.
There are many indicators to measure pulmonary ventilation function. Here, VC, FEV1, and PEF were selected because they are routinely measured in patients with rib fractures at our hospital and because of their operability and accuracy . First, we analyzed the PVF among patients with different locations of a single rib fracture. These locations (left vs. right vs. bilateral, anterior vs. posterior vs. lateral, and high vs. middle vs. low) did not affect the PVF parameters. Therefore, the location of a single rib fracture does not affect the PVF.
When a rib fracture occurs, a series of changes will happen in the thorax cavity and will affect the PVF, especially in multiple fractures (two or more fractures on the same rib). Multiple rib fractures will lead to an inability of the chest wall to support the effective thoracic expansion and have been shown to lead to ARF . Of course, patients with severe trauma and flail chest will have a sharp decline in PVF, and ARF will occur, requiring mechanical ventilation and increasing the risk of complications and hospitalization costs [15–17]. Nevertheless, most patients with fractured ribs but without flail chest will also have some degree of decreased PVF that can lead to complications, especially in elderly patients [8–10]. In the present preliminary study, there were no differences between patients with multiple and non-multiple rib fractures. This could be because patients with flail chest were excluded from the present study.
A previous study showed that higher numbers of fractured ribs would lead to a poorer prognosis in elderly patients . In the present study, when comparing the PVF between patients with ≤ 4 vs. ≥ 5 fractured ribs, the latter was significantly lower in VC, FEV1, and PEF than the former group, suggesting that we should pay more attention to those patients with ≥ 5 fractured ribs. Then, we compared the effect of the number of breakpoints, and similar results were observed, i.e., that ≥ 5 breakpoints was associated with a significant decline in PVF compared with ≤ 4 breakpoints, suggesting that the number of breakpoints is possibly more clinically meaningful than the number of fractured ribs.
Rib fractures can cause severe chest pain and affect the patients’ quality of life, especially in the early traumatic stage [19–21]. A study showed that effective pain relief could also improve the PVF of the patients . In the present study, PVF at admission, before any treatment, with cut-off points of ≥ 6 and ≥ 7 indicated worse PVF.
The clinical significance of rib fracture internal fixation for patients with flail chest has been confirmed , but the indications for patients without flail chest are still controversial [18, 24–26]. Considering that the degree of decline in PVF is often closely related to adverse prognosis, the degree of change in PVF could be an indication for the internal fixation for rib fractures. Internal fixation surgery can reduce the occurrence of post-traumatic complications and promote the recovery of pulmonary function . Nevertheless, this study was not designed to answer this question, and future studies will have to look into that.
This study has limitations. The number of patients was small. In addition, only the data available in the patient charts could be analyzed. The treatment outcomes could not be examined because many patients are returned home and can go to other hospitals for follow-up. In this study, 118 patients were treated with internal fixation for rib fractures, and there were no serious complications such as lung infections. Therefore, we could not test the association of the reduction in lung function with adverse complications (such as pulmonary infections, ventilator-assisted ventilation, hospitalization, and ICU stay).