Critically Appraised Topic: Is spirometry a safe and reliable measure for predicting complications and hospital length of stay in patients with rib fractures?
Study #1: This was a prospective observational study of adults admitted to the hospital with rib fractures. Inclusion criteria included patients age >60, 3+ rib fractures confirmed on imaging, with admission to the hospital. Patients were excluded if they were screened >24 hours after arriving to the ED, were injured >24 hours prior to arrival, significant additional MSK injury, or cognitive impairment that prevented cooperation with testing. Objective was to evaluate FVC, FEV1, and NIF as predictors of outcome in older adults with isolated rib fractures. Predicted it would identify patients who could safely be admitted to medical floor or even discharged from ED. Methods: Once included, pain was recorded with visual analog scale, grip strength, pain modalities utilized, and FEV1 FVC and NIF. FEV1, FVC, and NIF were then measured daily. Also recorded analgesia use, presence of chest tubes, hemothorax, pneumothorax. Primary outcomes were discharge home and LOS. Secondary outcomes: mortality, pneumonia, intubation, transfer to higher level of care, readmission (all examined at discharge and 30 days after discharge) Results: 346 patients with rib fractures identified, 86 ultimately fit all criteria and were consented. Higher spirometry values on admission [1.64(0.74) vs 1.25(0.79) p=0.033] and grip strength [45.3(22.2) vs 33.1(22.6) p=0.01] correlated with home discharge. Day 1 FEV1 significantly predicted discharge home - 3% increase (95% CI, 1–6%) for every percent increase in percent-predicted FEV1 (p = 0.023). Shorter LOS were seen with higher volume respiratory parameters with FEV1 being most predictive (β = −3.240, p = 0.001). Pain scores not predictive of any spirometry values (suggesting spirometry may be useful without pain levels as confounders) Change in spirometry not predictive of LOS. Patients upgraded to the step down unit or ICU did have lower percent-predicted FEV1 on admission (39.1% vs. 47.5%, p = 0.044)
Study #2: This was a retrospective chart review. Patients were included if they had fractured ribs and a VC recorded within 48 hours of admission. Exclusion criteria included pregnant patients, prisoners, and those without VC within 48 hours. Objective was to determine if vital capacity can be used for patients with rib fractures to predict disposition and complications (mortality, pneumonia, transfer to higher level of care, readmission). Methods: multiple VC taken throughout the day to guide management per institution protocol. Chart review utilized to collect average daily VC (percentage of predicted), demographics, LOS (and ICU LOS) and pulmonary complication (includes pneumonia, need for intubation, transfer to the surgical ICU, readmission for pulmonary reason, new home oxygen requirement). Results: 801 pts with rib fractures, 601 after exclusion criteria. Every 10% increase in predicted VC significant for lower odds ratio of DC to an extended care facility [OR 0.74 CI 0.65-0.84 p<0.0001). Additionally >50% VC compared to <30% had decreased odds [OR 0.17-0.51, p<.0001]. Increasing age, and age>55 also significant association for DC to ECF (p<0.001). Change in VC had no significance on discharge disposition. In regard to pulmonary complications, every increase in VC by 10% had decreased odds of complication [OR 0.64 CI 0.52-0.79, p<0.0001). Additionally >50% VC compared to <30% had decreased odds [OR 0.08-0.52, p=.02]. After multivariate analysis, risk factors for DC to ECF include age>55, >3 rib fractures, and injury severity score >15. Risks for pulmonary complication included VC <30%, =/>3 rib fractures, age>55.
Study 1: Strengths include study is prospective, and standardized equipment and protocol for measuring respiratory parameters were utilized. Testing results were not made available to treating clinicians to prevent treatment alterations secondary to this information. Patients >60 with 3+ rib fractures only included -allows to better control for these confounders to determine whether FVC/FEV1 effects disposition.
Limitations: Patient population is limited given those with difficulty cooperating were excluded. No formal power analysis done. Significant musculoskeletal injury is an exclusion criteria but not defined. Claim lack of relation between pain and respiratory parameters however not powered for this.
Study 2: Strengths include large sample size, treatment pathway was in place that utilizes VC making this measurement more reliable. Standardized equipment was utilized and best of 3 attempts recorded. Only included patients who had a VC within first 48 hours.
Limitations: Retrospective study, with inability to blind clinicians to VC. Data in this study was calculated using day 2 VC which is less relevant to our patient population in the ED. Also unclear why the author chose to look at day 2 rather than day 1. No formal power analysis. Includes all ages and #of rib fractures without subgroup analysis - possible > # of rib fractures and age lead to worse outcomes and happen to correlate with <VC/FEV1.
Based on my review of the literature I would consider functional respiratory parameters in my disposition of rib fracture patients, however not in isolation as there aren’t currently quality studies examining disposition of rib fracture patients from the ED utilizing FVC or FEV1 as a guide. Those with higher FVC/FEV1 may have lower risk of pulmonary complications and higher likelihood of DC home thus further studies examining utilizing FVC or FEV1 to DC patients home from the ED are needed to apply these principles to our population.
Schuster KM, Sanghvi M, O'Connor R, Becher R, Maung AA, Davis KA. Spirometry not pain level predicts outcomes in geriatric patients with isolated rib fractures. J Trauma Acute Care Surg. 2020 Nov;89(5):947-954. doi: 10.1097/TA.0000000000002795. PMID: 32467465.
Carver TW, Milia DJ, Somberg C, Brasel K, Paul J. Vital capacity helps predict pulmonary complications after rib fractures. J Trauma Acute Care Surg. 2015 Sep;79(3):413-6. doi: 10.1097/TA.0000000000000744. PMID: 26307874.