Adverse outcomes in younger rib fracture patients.

Background: Recent studies on the impact of rib fractures after blunt trauma have shown a linear relationship between age, increasing number of rib fractures, and complications, including mortality. Others have documented that age-related morbidity increases before age 65 in trauma patients. We hypothesize that patients as young as age 45 demonstrate increased morbidity with injuries similar to older patients.

Methods: We performed a retrospective cohort study involving all blunt trauma patients with rib fractures, excluding those with severe head and abdominal injuries and those dying within 24 hours, admitted between January 2001 and December 2004. Outcome parameters included pulmonary complications, ICU length of stay, hospital and ICU length of stay, Injury Severity Score (ISS), number of vent days, number of rib fractures, mechanism of injury, and discharge disposition.

Results: Of the 3,094 patients admitted, 307 met the inclusion criteria (9.9%). Based on statistical analysis of age, number of rib fractures, and adverse outcome variables, patients were separated into 4 groups: Group 1: younger than 44 years old with 1 to 4 rib fractures, Group 2: younger than 44 years with greater than 4 rib fractures, Group 3: 45 years or older with 1 to 4 rib fractures, and Group 4: 45 years or older with more than 4 rib fractures. Age groups and outcome variables were compared with chi-square, analysis of variance and multiple regression analysis. Respiratory failure, pneumonia, and associated thoracic injuries were increased in Group 4 patients compared with other groups (P < 0.05). Mortality and length of stay were not different between groups.

Conclusions: Patients as young as 45 with more than 4 rib fractures are at increased risk for adverse outcomes. Efforts to improve outcomes in rib fracture patients should focus not only on elderly patients, but on those as young as 45 years. Based on these data, we established a rib fracture clinical pathway focusing on patients 45 years and older with more than 4 rib fractures.

Key Words: elderly, rib fractures, pulmonary complications

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Recent studies have emphasized the unexpected frequency of rib fractures and the adverse impact they have on injured patients. (1,2) Work by Bulger et al (3) on the impact of rib fractures after blunt trauma has demonstrated the linear relationship between age, increasing numbers of rib fractures, and complications, including mortality. They documented that patients 65 years or older with more than four rib fractures demonstrated increased morbidity and mortality when compared with those aged 15 to 64. Lee et al (1) recommended that patients with more than four rib fractures be transferred to a Level 1 trauma center. Although geriatric trauma patients are a particularly vulnerable group and are increasing in number, most admissions to trauma centers are still younger than 65. In fact, recent studies have documented that age-related morbidity increases before age 65 in trauma patients. In addition, Trask (4,5) and others suggested that patients as young as 40 years of age demonstrate increased morbidity with similar injuries as older patients. We hypothesized that patients younger than age 65 with multiple rib fractures would demonstrate increased morbidity. These data could then be used to implement a multidisciplinary rib fracture pathway at our hospital.

Materials and Methods

We conducted a retrospective cohort study of all blunt trauma patients with rib fractures admitted to Wellmont Holston Valley Hospital, a Level 1 Trauma Center, from January 2000 to December 2004. This study was approved by the Wellmont Institutional Review Board. All data were recorded from the Holston Valley Hospital Trauma Registry and the medical record. During the study period, 3,094 patients were admitted to the trauma service, with 2,846 suffering blunt injury. Of these patients, 373 were diagnosed with rib fractures by either plain x-ray or CT scan. Exclusion criteria of death in the first 24 hours or an Abbreviated Injury Score (AIS) greater than 3 for head and abdominal injuries were established to minimize their confounding impact on pulmonary status, yielding 307 (9.9%) patients eligible for the study. Patients who were admitted with rib fractures, but could not be determined to have new fractures upon review of their chest x-ray or CT scan, were excluded from the study.

A rib fracture database was constructed with data abstracted from the trauma service supplemented from radiology electronic records. The trauma registry was reviewed for demographic data, mechanism of injury, Abbreviated Injury Scores (AIS), Injury Severity Score (ISS), and mortality. ISS was based on the 1998 AIS scores for each body region. Details regarding the number and location of rib fractures along with the presence or absence of pneumothorax, hemothorax, pulmonary contusion, and other associated thoracic injuries were taken directly from the radiology reports and, when necessary, review of the individual chest x-rays or CT scans. The infection control continuous quality improvement database was queried for the length of ICU stay, total length of stay, ventilator days, pneumonia and acquired respiratory distress syndrome (ARDS). This continuous quality improvement process prospectively collects outcomes data in our ICU and is used in a variety of ongoing performance improvement efforts. The pharmacy database was used to document analgesia method (continuous or nurse-delivered IV narcotic infusion, patient-controlled analgesia, oral narcotics, or epidural). No standardized rib fracture protocol that included uniform ICU or step-down unit admission criteria pain control measures, scheduled CT scanning, or pulmonary function evaluation was used during the time frame of this study. Statistical analyses were performed by multiple regression analysis, ANOVA, and chi-square. Significance was set at P < 0.05.

Results

During the study period there were 307 patients. Men comprised 69% of all patients, overall average age was 49, average ISS was 17.4, average number of rib fractures was 6.5, average hospital days 7.6, ICU days 2.1, and overall mortality was 2.3%. There were seven deaths. Patients were initially divided into 8 age groups stratified by number of rib fractures and outcome variables. (Table 1) Figure 1 and Figure 2 show associated thoracic injuries and pulmonary complications stratified by age and number of rib fractures.

From an analysis of the data, patients were organized into four groups based on age and number of rib fractures: Group 1: 1 to 44 years, with 1 to 4 rib fractures, Group 2: 1 to 44 years, with more than 4 rib fractures; Group 3: 45 years or more, with 1 to 4 rib fractures; and Group 4: 45 years or more, with more than 4 rib fractures. Table 2 and Figure 3 depict the demographic, associated injury profile, and outcomes for each group.

Older patients with more fractures comprised the majority of the patients. Average ISS and age were higher than some reports. (2,5) The dependent variable of age was different between Groups 1 and 2 versus 3 and 4; the dependent variable of rib fracture was different between Groups 1 and 3 versus 2 and 4.

Because Groups 2 and 4 included patients with greater than 4 rib fractures, their chest AIS scores and corresponding ISS scores were higher, reflecting the sum of squares of the highest three AIS scores. Both younger and older groups with more than 4 rib fractures had severe injuries, but had similar hospital and ICU days. Older patients with multiple rib fractures suffered more associated thoracic injuries and pulmonary complications (P < 0.05).

Discussion

Rib fractures are very common injuries, comprising up to 10% of admissions to trauma services. (3,4) This rate of admission is similar across studies, and is repeated in our study. Rib fractures are commonly associated with pulmonary contusions, a significant risk factor for pulmonary complications that may contribute more than is commonly appreciated to pulmonary morbidity seen in multisystem injured patients. Bulger and associates (3) recently highlighted the detrimental effects of increasing number of rib fractures and age. They demonstrated that patients with more than four rib fractures and age greater than 65 exhibit increased morbidity and mortality. Their data support the preponderance of information that the elderly trauma patient, aged 65 and older, demonstrates worse outcomes with similar injuries than younger patients and underscore why they are often placed in special care unit beds for seemingly minor injuries. (4,5)

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Although elderly trauma patients are certainly a vulnerable group, it is unclear at what age and number of rib fractures morbidity and mortality actually increase. Holcomb and Moore (6) presented data to demonstrate that patients with more than four rib fractures who are older than age 45 exhibit increased morbidity, including increased ventilator days, ICU days, and hospital days. They showed that increasing number of rib fractures causes significant morbidity in a younger population than previously appreciated, probably reflecting the increasing energy transmitted to the chest wall, underlying intrathoracic organs, and pulmonary parenchyma. (7) Our similarly designed study showed that Group 4 patients, those older than 45 with more than 4 rib fractures, are at higher risk for pulmonary complications, including respiratory failure and pneumonia, and suffer more associated thoracic injuries. Their overall ICU days, hospital days, and mortality were not different from Groups 1, 2, and 3.

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Adequate pain control is critical to the outcome of rib fracture patients. All patients in our study received IV pain medication, either through nurse-delivered intermittent bolus or patient-controlled devices and were gradually "switched over" to oral narcotics as tolerated before discharge. Epidural catheters were infrequently used in our patients. Holcomb and Moore's study (6) did not reveal the decreased incidence of morbidity or mortality with epidural pain control reported by others. Possible reasons for this lack of expected beneficial effect include technical difficulty in placement, hemodynamic instability after initiation, and early dislodgement with patient movement. One of the reasons why epidurals were not used in our study was the concern for increased complications. Risk factors for these complications include fever, elevated white blood cell count, prolonged placement, and multiple injuries. Paradoxically, these risk factors are present in most, if not all, trauma patients who would most likely benefit from enhanced pain control. (8)

Major intrathoracic injuries associated with rib fractures were significant (Table 2) and more frequent in Group 4 patients (P < 0.05). Hemothorax and pulmonary contusions were common, as were thoracic spinal fractures, sternal, and clavicular fractures. There were 2 aortic injuries in the younger age group and 2 diaphragm injuries in the older group. Abdominal injuries including liver and splenic injuries were frequent across age groups. The data in Table 2 document the variety and frequency of associated significant parenchymal injuries and the energy transmitted to these patients, attesting to the importance of heightened clinical attention to patients suffering rib fractures.

Morris (9) and Scalea (10) attributed the poorer outcomes in elderly patients to a decreased physiologic reserve, significant comorbidities, or limited ability to respond to seemingly minor hemodynamic challenges, and recommended aggressive ICU hemodynamic monitoring to improve outcomes. Miller et al (9) and others measured pulmonary contusion volume on CT scan to assess risk for ARDS. The increased morbidity seen at the relatively young age of 45 may be attributed to the combination of direct pulmonary injury, pulmonary complications, and other intrathoracic injury caused by the energy transfer from more than four rib fractures. The combination of significant injury and inadequate pain control may lead to increases in pneumonia and respiratory failure. (3)

Our study has several limitations, mainly those of a retrospective review. Documentation of dynamic pain scores, allowing accurate evaluation and titration of the patient's analgesia would be optimal. Likewise, daily pulmonary function evaluations to assess adequacy of pain control should be recorded. Comorbidities and nutritional and functional status at admission and discharge were unavailable. (3) We excluded patients with abdominal and head AIS scores of greater than 3 (55 patients) to reduce confounding pulmonary outcomes, although Holcomb and Moore excluded patients' AIS scores as low as 2 for these area injuries. Eleven patients died within the first 24 hours and were excluded. There were 307 patients left in the study.

We have started a clinical pathway for rib fracture patients using entry criteria based on respiratory function, pain control assessment, nutritional, and physical therapy. Clinical pathways have been used to improve patient care in high-risk medical and trauma patients. (12) Common injuries such as rib fractures may be better managed with the help of guidelines generated by evidence-based medicine as promulgated by the Eastern Association for Surgery of Trauma. (7)

In conclusion, patients as young as age 45 with more than 4 rib fractures are at risk for pneumonia and respiratory failure and may have significant associated injuries. This group requires optimal pain control through focused multidisciplinary efforts.

References

1. Lee RB, Bass SM, Morris Jr, JA MacKenzie EJ. Three or more rib fractures as an indicator for transfer to a level 1 trauma center: a population-based study. J Trauma 1990;30:689-694.

2. Zeigler DW, Agarwal NN. The morbidity and mortality of rib fractures. J Trauma 1994;37:975-979.

3. Bulger EM, Arneson MA, Mock CN, Jurkovich GJ. Rib fractures in the elderly. J Trauma 2000;48:1040-1047.

4. Demetriades D, Sava J, Alo K, et al. Old age as a criterion for trauma team activation. J Trauma 2001;51:754-757.

5. Trask A, Perdue PW, Watts DD, Kaufmann CR. Differences in mortality between elderly and younger trauma patients: geriatric status increases risk of delayed death. J Trauma 1998;45:805-810.

6. Holcomb JB, Moore FA. Increased morbidity from rib fractures after age 45. J Am Coll Surg 2003;196:549-555.

7. Miller PR, Croce MA, Bee TK, et al. ARDS after pulmonary contusion: accurate measurement of contusion volume identifies high-risk patients. J Trauma 2001;51:223-230.

8. Kurek SJ, Lageres-Garcia J, Casella R, et al. Complications of epidural infusions for anesthesia in postoperative and trauma patients. Am Surg 1997;63:543-546.

9. Morris Jr, JA MacKenzie EJ, Edelstein SL. The effect of preexisting conditions on mortality in trauma patients. JAMA 1990;263:1942-1946.

10. Scalea TM, Simon HM, Duncan AO, et al. Geriatric blunt multiple trauma: improved survival with early invasive monitoring. J Trauma 1990;30:129-136.

11. Sesperez J, Wilson S, Jalaludin B, et al. Trauma case management and clinical pathways: prospective evaluation of their effect on selected patient outcomes in five key trauma conditions. J Trauma 2001;50:643-649.

12. Fabian TC. Evidence-based medicine in trauma care: whither goest thou? J Trauma 1999;47:225-232.

George M. Testerman, MD

From the Wellmont Holston Valley Hospital Trauma Center, Kingsport, TN.

Reprint requests to George M. Testerman, MD, Wellmont Holston Valley Hospital Trauma Center, 134 West Park Drive, Kingsport, TN 37660. Email: [e-mail]

Accepted November 29, 2005.

RELATED ARTICLE: Key Points

* Rib fractures are common thoracic injuries. Recent studies have shown increased morbidity and use of hospital resources in elderly rib fracture patients.

* Our study demonstrated that patients as young as 45 with more than 4 rib fractures are at increased risk for adverse outcomes.

* Efforts to improve outcomes in rib fracture patients should focus not only on elderly patients, but on those as young as 45.

Table 1. Demographics, outcomes by 8 age groups

Age groups  Patients  No. of rib  Length of stay  ICU length of
(yrs)       no.       fractures   (days)          stay (days)

0-24        33        6.9          6.9            2.7
25-34       39        6.3          7              1.2
35-44       34        7.0          6.9            3.3
45-54       54        6.6          8.2            1.7
55-64       44        6.6          9.2            2.4
65-74       39        6.4          5.5            1
75-84       28        6.9         10.8            4.3
> 85        14        6.0         10.3            2.9
P value     NS        NS          NS              NS

Age groups  Days on     Associated
(yrs)       ventilator  thoracic injuries  Deaths (%)     % Home

0-24        1.7         41                 0              94
25-34       0.9         33                 0              95
35-44       1.2         40                 1 (1.8)        86
45-54       1.2         44                 1 (1.8)        89
55-64       1.5         47                 0              91
65-74       0           33                 2 (6.1)        77
75-84       2.4         11                 1 (3.7)        52
> 85        1.6         31                 2 (15)         54
P value     NS          NS                 P < 0.05 (NS   P < 0.05
                                           for < 85 yrs)

ICU, Intensive care unit; % Home, % patients discharged home; NS, not
significant.

Table 2. Pulmonary complications and outcomes

                     Group 1   Group 2   Group 3   Group 4    P value
Variables            N (%)     N (%)     N (%)     N (%)

Patients             44 (14)   90 (29)   67 (22)   115 (37)
Complications         1 (2.2)  17 (18)    2 (3.2)   32 (28)   P < 0.05
Rib fractures         2         9         1.9        8.7
Age                  32        32        64         64
Thorax injuries      14 (5)    39 (13)   14 (5)     51 (17)   P < 0.05
Hospital days         4         8         3.8       10.6      NS
ICU days              0.18      1.6       3.9        3.02     NS
Ventilator days       0.14      1.68      0.12       3.07     NS
Deaths                0         1 (1.1)   1 (1.6)    5 (4.3)  NS
Pulmonary contusion   6        17         3         13
Hemothorax            2        11         1         12
Aortic lac            0         2         1          0
T-spine               5         6         2          3
Liver lac             1         9         2          5
Spleen lac            4        11         3          2
Diaphragm             0         0         1          2
Sternal fracture      1         1         1          2

Group 1, age less than 45 and 1 to 4 rib fractures; Group 2, age less
than 45 and more than 4 rib fractures; Group 3, age over 45 and 1 to 4
rib fractures; Group 4, age over 45 more than 4 rib fractures; NS, not
significant; lac, laceration.