Page 110 - JSOM Spring 2023

long-lasting implications for returning to duty and medical For purposes of analysis, patients were grouped based on pre-
readiness. A study found that combat thoracic injury led to sentation % pFVCs into three groups: % pFVC 0–29% (low),
statistically significant odds of abnormal spirometry by pul- 30–49% (moderate), and >50% (high). 10–12 Primary outcomes
monary function testing (PFTs). 8 were defined as pulmonary complications to include pneumo-
nia, acute respiratory distress syndrome (ARDS), pulmonary
Many protocols for admission and management of rib frac- embolism (PE), retained hemothorax, empyema, aspiration,
tures are based on the number of ribs broken and the age of required intubation, and ICU readmission or escalation of
the patient, as opposed to metrics of pulmonary physiology care. Due to the potential confounding factor of chest tube
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of the individual patient. One long-established reliable metric management on LOS, a separate analysis was conducted ex-
that can be simply performed at the bedside is FVC. This is cluding patients with a pneumothorax or hemothorax that
9
defined as the total volume of air that can be exhaled force- required a chest tube to be placed.
fully. In retrospective studies, FVC < 30% predicted is associ-
ated with increased pulmonary complications; however, there SPSS Statistics 28 (IBM, https://www.ibm.com/spss) was used
are no prospective data on spirometry for prognostication. 9 to perform all statistical analysis. ANOVA and linear regres-
sion with Pearson correlation was used to evaluate relation-
This study prospectively evaluates patients suffering multiple ships between continuous variables, and Spearman correlation
rib fractures using an assessment of FVC, hypothesizing that was used for rank order (% pFVC groups) variables. T-tests
an increased % pFVC is associated with improved outcomes, were used to compare continuous variable means between
to include decreased rates of complications and reductions in outcome groups (discharge destination). A Chi-squared trend
ICU LOS, hospital LOS, and discharge to a rehabilitation or test was used for comparison of % pFVC groups and categor-
long-term care facility. As the US military and partners pre- ical variables. Finally, the overall study design and manuscript
pare for future conflicts such as large-scale combat (LSCO) submission was completed under the Strengthening the Re-
and multi-domain operations (MDO), the ability to effectively porting of Observational Studies in Epidemiology (STROBE)
triage, diagnose, and manage blunt chest trauma patients in statement guidelines and reporting requirements.
theater for prolonged periods of time could help determine
how to best utilize medical resources in environments in which Results
medical assets and critical care evacuation are limited.
During the study period, 181 patients were admitted with
three or more rib fractures. Twenty-six patients were excluded,
Methods
and FVC was not measured for 73 patients. This resulted in a
We conducted a prospective observational study of trauma pa- total of 79 patients included in the analysis (Figure 1). Median
tients consecutively admitted to a military level I trauma cen- age was 60 years (range: 20–87). Mean number of total rib
ter with three or more rib fractures identified on radiographic fractures was 6.37 (range: 3–19). Mean injury severity score
imaging at time of admission between July 2018 and March (ISS) was 13.5 (range: 4–43). All patients (n = 79) suffered a
2019. Patients intubated prior to arrival to the ICU, with cer- blunt mechanism of injury. Overall, average hospital LOS was
vical spinal cord injury (SCI), moderate to severe traumatic 6.5 days (range: 1–26). Overall, 21.5% (n = 17) of patients
brain injury (TBI), pregnancy, or who were incarcerated were required discharge to a rehabilitation facility, and there was
excluded. FVC was measured within six hours of admission one mortality. Average hospital and ICU LOS were 6.5 days
and throughout their hospitalization as part of our standard (range: 1–26) and 2.9 days (range: 1–22), respectively.
clinical care defined in our clinical practice guideline, utiliz-
ing the Wright Mark 8 respirometer (nSpire Health, https:// FIGURE 1 Patient inclusion and exclusion per protocol.
nspirehc.com/) or an Easy One Air Spirometer (Ndd Medical Total Patients
Technologies, https://nddmed.com/). Clinical care, including N = 181
administration of analgesics and other interventions, remained
at the discretion of the provider managing the patient and was Exclusions: 29
not delayed for measurement of FVC. Additionally, care was Failure to obtain Declined participation: 3
guided by our Early Aggressive Chest Intervention (EACI = admission FVC: 73 Age >89: 4
“EASY”) Rib Fracture Protocol, a clinical practice guideline SCI: 2
for our institution (Appendix A). Prior intubation: 20

Patients’ % pFVC were calculated as a comparison of measured Included in study
FVC relative to predicted values from previously established N = 79
US population reference data. Patient data including height,
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weight, race, age, sex, smoking status, presence of pulmonary
comorbidities, associated pneumothorax, hemothorax or flail
chest, and injury severity score were abstracted from each pa-
tient’s electronic medical record. Additionally, data were col- FVC 0–29% FVC 30–49% FVC 50+%
lected on interventions performed and events during admission, N = 23 N = 36 N = 20
including number of packed red blood cells (pRBC) transfused
in the first 24 hours following admission, placement of an epi- FVC = forced vital capacity, SCI = spinal cord injury
dural catheter or performance of a paravertebral nerve block,
placement of a chest tube, performance of video-assisted tho- No significant demographic variability was identified between
racoscopic surgery (VATS), tracheostomy, rib plating, discharge groups (Table 1). Variables noted to be significantly associated
to a medical facility other than patient’s home, and mortality. with reduced % pFVC were the presence of pneumothorax, in

108 | JSOM Volume 23, Edition 1 / Spring 2023