a b s t r a c t

Introduction: Pneumonia is a known complication following rib fractures. This study was undertaken to identify clinical and demographic factors associated with the development of pneumonia among trauma patients with rib fractures.

Methods: This retrospective study examined trauma patients with one or more rib fractures, who were admitted for inpatient management during the time period 2012 through 2017. Variables studied included age, gender, in- jury severity score (ISS), mechanism of injury, smoking status, alcohol use, administration of influenza And pneu- mococcal vaccine, number and side of rib fracture(s), pulmonary contusion, pneumothorax, flail chest, spirometer use, blood transfusion, and intravenous fluid administration.

Results: Among 78 cases and 74 controls (matched for age and ISS), patients who developed pneumonia were more likely to be male, have higher number of rib fractures, alcohol consumption of 1-5 drinks per day, and a higher initial Volume of intravenous fluids during first 24 h. Patients with pneumonia were more likely to be treated with incentive spirometry. There were no difference in age, ISS, smoking status, side of rib fractures, pul- monary contusion, pneumothorax, flail chest, influenza vaccination, pneumonia vaccination, or mechanism of in- jury between the two groups.

Conclusion: Risk factors for the development of pneumonia following rib fractures include male gender, higher number of rib fractures, alcohol consumption, and higher rates of intravenous fluid administration during the ini- tial 24 h following trauma.

(C) 2019

Introduction

Pneumonia is an infection of the alveoli that may be caused by a va- riety of pathogens, often bacteria, viruses, or fungi. Pneumonia results in significant morbidity and mortality, and is the eighth leading cause of death in the United States [1-3]. Risk factors for pneumonia include as- piration risk, endotracheal intubation, indwelling medical devices, alco- holism, smoking, poor dental hygiene, extremes of age, malignancy, immunosuppression, pulmonary disease, and underlying comorbidities, such as diabetes [4-7].

Blunt trauma to the chest produces damage by direct force, and/or forces of acceleration or deceleration. Injuries to the thorax comprise approximately 4% of ED visits [8]. Rib fractures may lead to the compli- cation of pneumonia, possibly by compromising Respiratory function

* Corresponding author at: Department of Emergency Medicine, Wright State University Boonshoft School of Medicine, 3525 Southern Boulevard, Kettering, OH 45429, United States.

E-mail address: [email protected] (C.A. Marco).

[13,14]. Previous studies have demonstrated that higher number of rib fractures is associated with pulmonary complications [9].

This study was undertaken to identify clinical and demographic fac- tors associated with the development of pneumonia after rib fractures among admitted trauma patients.

Methods

This retrospective chart review study was approved by the Wright State University Institutional Review Board. Eligible participants in- cluded all trauma patients admitted at Miami Valley Hospital, a Level 1 trauma center, with one or more rib fractures, from 2012 through 2017. Exclusion criteria included trauma patients without rib fractures. Eligible participants were identified by the institutional trauma registry and the electronic health record. Complication of pneumonia was iden- tified by a discharge diagnosis that included pneumonia. Controls (ad- mitted patients with rib fracture(s) without pneumonia), were matched to cases, based on age and injury severity score.

Data were analyzed using SAS v9.4. Categorical variables are de- scribed with frequency count (percentage) [95% confidence interval]

https://doi.org/10.1016/j.ajem.2019.10.021

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C.A. Marco et al. / American Journal of Emergency Medicine 38 (2020) 610–612 611

and tested between groups using Chi-square or Fisher’s Exact test (for alcohol use). Continuous variables are described with median and inter- quartile range and compared between groups with Mann Whitney Wilcoxon tests or Student T-test (for age).

Results

Among 78 cases and 74 controls (matched for age and ISS), patients who developed pneumonia were more likely to be male (p = 0.005), have higher number of rib fractures (p = 0.05), alcohol consumption of 1-5 drinks per day (p = 0.05), and a higher initial volume of intrave- nous fluids during first 24 h (p b 0.001). Patients with pneumonia were more likely to be treated with incentive spirometry (p b 0.001). (Table 1).

There were no significant differences in age, ISS, smoking status, side of rib fractures, pulmonary contusion, pneumothorax, flail chest, influ- enza vaccination, pneumonia vaccination, or mechanism of injury be- tween the two groups.

Discussion

This study identified an increased incidence of pneumonia in men following rib fractures. These findings confirm previous stud- ies which have identified higher incidence and severity of trauma among male patients. A study of 427,933 trauma patients using the National Trauma Database found higher rates of ARDS, pneu- monia, pulmonary embolism, deep vein thrombosis, wound infec- tion, and Intra-abdominal abscesses in men [10]. A study by McKinley et al found men to have a 58% greater chance of develop- ing a major infection when compared to their female counterparts [11]. Females have higher early morbidity following trauma, which may contribute to lower incidence of infectious complications such as pneumonia [12].

The total number of rib fractures was associated with increased inci- dence of pneumonia in our patient population [13]. The RibScore was developed to assess risk of pneumonia, respiratory failure, and tracheos- tomy, based on six clinical criterion, including six or more rib fractures,

bilateral fractures, flail chest, three or more severely (bicortical) displaced fractures, first rib fracture, and at least one fracture in all three anatomic areas (anterior, lateral, and posterior) [14]. The relation- ship is believed to be related to increased pain resulting in atelectasis. The strength of this association may have been reduced in our review due to the implementation of a rib fracture protocol in January 2016. This protocol involved multimodal pain management, incentive spi- rometry, EZ-PAP, and surgical fixation. A similar protocol implemented with elderly trauma patients with rib fractures has shown a dramatic re- duction in pneumonia [15].

Alcohol use was associated with the development of pneumo- nia following rib fractures. Alcohol use is associated with increased risk of trauma [16-18]. These findings confirm previous reported data that alcohol use is associated with delayed recovery, immuno- suppression, and increased complications following trauma [19, 20].

Intravenous fluid administration was associated with the develop- ment of pneumonia following rib fractures. Despite the higher sensitiv- ity of CT scan for both fractures and pulmonary contusions, on initial CXR, the presence of any pleural or parenchymal abnormality signifi- cantly increased the incidence of pneumonia, respiratory failure, trach and mortality [21]. Injury to lung parenchyma and respiratory failure may be worsened by congestive heart failure and excess fluid adminis- tration [22]. Excess intravenous fluid administration has been associ- ated with poorer outcomes among critical patients [23,24]. Excess intravenous fluid administration has been associated with coagulopa- thy, pulmonary edema, and other complications [25]. Intravenous fluids should be administered in appropriate volumes in the setting of Thoracic trauma.

Limitations

This study was conducted at a single institution, and results may not be generalizable to other settings. Due to the retrospec- tive study design, missing or Inaccurate data may have affected the results.

Table 1

Demographic and clinical variables associated with pneumonia following rib fractures among admitted trauma patients.

^b Some patients with multiple rib fractures did not have the number of rib fractures documented. These were coded as “2”.

612 C.A. Marco et al. / American Journal of Emergency Medicine 38 (2020) 610–612

Conclusions

Risk factors for the development of pneumonia following rib frac- tures include male gender, higher number of rib fractures, alcohol con- sumption, and higher rates of intravenous fluid administration during the initial 24 h following trauma.

Acknowledgement

The authors wish to thank Nancy Buderer, MS, for her statistical ex- pertise, and Aimee Kasperski for her assistance with data collection.

Appendix A. Supplementary material

Supplementary data to this article can be found online at https://doi. org/10.1016/j.ajem.2019.10.021.

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