Association of ROX Index with Mechanical Ventilator Use in Sepsis Patients in the Emergency Department

The utility of the respiratory rate-oxygenation index as a predictor of treatment response in dogs receiving high-flow nasal cannula oxygen therapy

Objective

This study aims to evaluate the respiratory rate-oxygenation index (ROX) and the ratio of pulse oximetry saturation (SpO2) to the fraction of inspired oxygen (FiO2) (SpO2/FiO2, [SF]) to determine whether these indices are predictive of outcome in dogs receiving high-flow nasal cannula oxygen therapy (HFNOT).

Design

This is a prospective observational study.

Setting

This study was carried out at two university teaching hospitals.

Animals

In total, 88 dogs treated with HFNOT for hypoxemic respiratory failure due to various pulmonary diseases were selected.

Measurements and main results

The ROX index was defined as the SF divided by the respiratory rate (RR). ROX and SF were calculated at baseline and for each hour of HFNOT. The overall success rate of HFNOT was 38% (N = 33/88). Variables predicting HFNOT success were determined using logistic regression, and the predictive power of each variable was assessed using the area under the receiver operating curve (AUC). ROX and SF were adequately predictive of HFNOT success when averaged over 0-16 h of treatment, with similar AUCs of 0.72 (95% confidence interval [CI] 0.60-0.83) and 0.77 (95% CI 0.66-0.87), respectively (p < 0.05). SF showed acceptable discriminatory power in predicting HFNOT outcome at 7 h, with an AUC of 0.77 (95% CI 0.61-0.93, p = 0.013), and the optimal cutoff for predicting HFNC failure at 7 h was SF ≤ 191 (sensitivity 83% and specificity 76%).

Conclusion

These indices were easily obtained in dogs undergoing HFNOT. The results suggest that ROX and SF may have clinical utility in predicting the outcomes of dogs on HFNOT. Future studies are warranted to confirm these findings in a larger number of dogs in specific disease populations.

Risk factors for delayed hemothorax in patients with rib fracture in the emergency department

OBJECTIVES

Although rib fractures are a risk factor, not all rib fracture patients will develop delayed hemothorax. This study aimed to evaluate risk factors which can identify rib fracture patients in the emergency department who may develop delayed hemothorax.

METHODS

Adult patients seen in the emergency room between January 2016 and February 2021 with rib fractures caused by blunt chest trauma were included in this retrospective observational study. Patients who underwent chest tube insertion within 2 days and those without follow-up chest radiographs within 2-30 days were excluded. We used a stepwise backward-elimination multivariable logistic regression model for analysis.

RESULTS

A total of 202 patients were included in this study. The number of total (P < 0.001), lateral (P = 0.019), and displaced (P < 0.001) rib fractures were significantly associated with delayed hemothorax. Lung contusions (P = 0.002), and initial minimal hemothorax (P < 0.001) and pneumothorax (P < 0.001) were more frequently associated with delayed hemothorax. Age (adjusted odds ratio (aOR) 1.03, 95% confidence interval (CI) 1.00-1.06, P = 0.022), mechanical ventilator use (aOR 9.67, 95% CI 1.01-92.75, P = 0.049), initial hemothorax (aOR 2.21, 95% CI 1.05-4.65, P = 0.037) and pneumothorax (aOR 2.99, 95% CI 1.36-6.54, P = 0.006), and displaced rib fractures (aOR 3.51, 95% CI 1.64-7.53, P = 0.001) were independently associated with delayed hemothorax.

CONCLUSIONS

Age, mechanical ventilation, initial hemo- or pneumothorax, and displaced rib fractures were risk factors for delayed hemothorax. Patients with these risk factors, and especially those with ≥2 displaced rib fractures, require close chest radiography follow-up of 2-30 days after the initial trauma.

Characteristics of rib fracture patients who require chest computed tomography in the emergency department

BACKGROUND

The disadvantages and complications of computed tomography (CT) can be minimized if CT is performed in rib fracture patients with high probability of intra-thoracic and intra-abdominal injuries and CT is omitted in rib fracture patients with low probability of intra-thoracic and intra-abdominal injuries. This study aimed to evaluate the factors that can identify patients with rib fractures with intra-thoracic and intra-abdominal injuries in the emergency department among patients with rib fracture.

METHODS

This retrospective observational study included adult patients (age ≥ 18 years) diagnosed with rib fracture on chest radiography prior to chest CT due to blunt chest trauma in the emergency department who underwent chest CT from January 2016 to February 2021. The primary outcomes were intra-thoracic and intra-abdominal injuries that could be identified on a chest CT. Multivariate logistic regression analysis was performed.

RESULTS

Among the characteristics of rib fractures, the number of rib fractures was greater (5.0 [3.0-7.0] vs. 2.0 [1.0-3.0], p < 0.001), bilateral rib fractures were frequent (56 [20.1%] vs. 12 [9.8%], p = 0.018), and lateral and posterior rib fracture was more frequent (lateral rib fracture: 160 [57.3%] vs. 25 [20.5%], p < 0.001; posterior rib fracture: 129 [46.2%] vs. 21 [17.2%], p < 0.001), and displacement was more frequent (99 [35.5%] vs. 6 [6.6%], p < 0.001) in the group with intra-thoracic and intra-abdominal injuries than in the group with no injury. The number of rib fractures (adjusted odds ratio [aOR], 1.44; 95% confidence interval [CI], 1.16-1.78; p = 0.001), lateral rib fracture (aOR, 2.80; 95% CI, 1.32-5.95; p = 0.008), and posterior rib fracture (aOR, 3.18; 95% CI, 1.45-6.94; p = 0.004) were independently associated with intra-thoracic and intra-abdominal injuries. The optimal cut-off for the number of rib fractures on the outcome was three. The number of rib fractures ≥ 3 (aOR, 3.01; 95% CI, 1.35-6.71; p = 0.007) was independently associated with intra-thoracic and intra-abdominal injuries.

CONCLUSION

In patients with rib fractures due to blunt trauma, those with lateral or posterior rib fractures, those with ≥ 3 rib fractures, and those requiring O₂ supplementation require chest CT to identify significant intra-thoracic and intra-abdominal injuries in the emergency department.