Performance of the CORB (Confusion, Oxygenation, Respiratory Rate, and Blood Pressure) Scale for the Prediction of Clinical Outcomes in Pneumonia

Reyes, Luis F.; Bastidas, Alirio R.; Quintero, Eduardo Tuta; Frías, Juan S.; Aguilar, Álvaro F.; Pedreros, Karen D.; Herrera, Manuela; Saza, Laura D.; Nonzoque, Alejandra P.; Bello, Laura E.; Hernández, Maria D.; Carmona, Germán A.; Jaimes, Anyelinne; Ramírez, Silvia M; Murillo, Natalia

doi:https://doi.org/10.1155/2022/4493777

Canadian Respiratory Journal

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Research Article | Open Access

Volume 2022 | Article ID 4493777 | https://doi.org/10.1155/2022/4493777

Performance of the CORB (Confusion, Oxygenation, Respiratory Rate, and Blood Pressure) Scale for the Prediction of Clinical Outcomes in Pneumonia

Luis F. Reyes,^1,2Alirio R. Bastidas ,¹Eduardo Tuta Quintero,¹Juan S. Frías,¹Álvaro F. Aguilar,¹Karen D. Pedreros,¹Manuela Herrera,¹Laura D. Saza,¹Alejandra P. Nonzoque,¹Laura E. Bello,¹Maria D. Hernández,¹and Germán A. Carmona¹ et al.

Academic Editor: Theodoros I. Vassilakopoulos

Received08 Sept 2021

Revised31 Mar 2022

Accepted27 Apr 2022

Published03 Jun 2022

Abstract

Background. Community-acquired pneumonia (CAP) is a common cause of morbidity and mortality due to misdiagnosis and inappropriate treatment approaches. Objective. To assess the performance of the CORB score in subjects with CAP for predicting in-hospital mortality, death within 30 days of admission, and requirement for invasive mechanical ventilation (IMV) and vasopressor support. Methods. A retrospective, cohort study with diagnostic test analysis of CORB and CURB-65 scores in subjects with CAP according to ATS criteria was undertaken. An alternative CORB score was estimated by replacing SpO₂ ≤90% by the SpO₂/FiO₂ ratio. Crude and adjusted odd ratios (AOR) were calculated for each variable. The area under the receiver operating characteristics curve (AUROC) was constructed for each score, and outcomes were analyzed. AUROCs were compared with the DeLong test, considering a p value statistically significant. Results. From 1,811 subjects who entered the analysis, 15.1% (273/1,811) died in hospital, 8.78% required IMV (159/1,811), and 9.77% (177/1,811) needed vasopressor support. CORB had an AUROC of 0,660 (95% CI: 0,623–0,697) for in-hospital mortality; an AUROC of 0,657 (95% CI: 0,621–0,692) for 30-day mortality; an AUROC of 0,637 (CI 95%: 0,589–0,685) for IMV requirement; and an AUROC of 0,635 (95% CI: 0,589–0,681) for vasopressor support. CORB performance increases when the SpO₂/FiO₂ ratio <300 is used as oxygenation criterion in the prediction of requirement for IMV and vasopressor support, with AUROC of 0,700 (95% CI: 0,654–0,746; ) and AUROC of 0,702 (95% CI: 0,66–0,745; ), respectively. CURB-65 score presents an in-hospital mortality AUROC of 0,727 (95% CI: 0,695–0,759) and 30-day mortality AUROC of 0,726 (95% CI: 0,695–0,756). Conclusions. CORB score has a good performance in predicting the need for IMV and vasopressor support in CAP patients. This performance improves when the SpO₂/FiO₂ ratio <300 is used instead of the SpO2 ≤90% as the oxygenation parameter. CURB-65 score is superior in the prediction of mortality.

1. Introduction

Community-acquired pneumonia (CAP) continues to be one of the main causes of morbidity and mortality; its occurrence in adults is estimated at approximately 16 to 23 cases per 1,000 person-years, and it increases with age [1]. It is the leading cause of death from infection worldwide [2, 3]. A global mortality of 10% to 14% is attributed to it, being less than 2% in healthy young people. However, mortality can increase to 11%–14% in adults who require hospitalization and may reach 25% to 50% in patients who are admitted to an intensive care unit (ICU) [4, 5]. Its early recognition and treatment are essential to avoid an ICU delayed admission, which is considered an independent factor related to a long hospital stay and higher mortality rates [6]. For this reason, different scores have been created and validated to carry out an effective prognostic identification, thus providing a guide to the most appropriate site for handling and monitoring the CAP patient.

Among the most widely used scores to predict mortality are the PSI (pneumonia severity index) [5, 7] and CURB-65 (confusion, urea nitrogen >7 mmol/L (19 mg/dL), respiratory rate ≥30/min, systolic blood pressure <90 mmHg or diastolic blood pressure ≤60 mmHg, and age ≥65 years) [8]. Additionally, given their superiority in predicting the need for ICU or mechanical ventilation, the criteria for pneumonia severity of the Infectious Diseases Society of America/American Thoracic Society (IDSA/ATS) [5, 8] and the SMART-COP score have been used [9]. However, one of the restrictions to applying these scores in different care settings is the need to perform at least one invasive procedure.

In search of a practical score that does not require the use of invasive measures in its construction, Buising et al. [10] proposed in 2007 the CORB score, which uses the information of consciousness state, oxygen saturation by pulse oximetry, respiratory rate, and blood pressure, reaching a sensitivity of 72.2% and a specificity of 70.1% for a composite outcome of mortality and requirement for invasive mechanical ventilation (IMV) and vasopressor support [10, 11]. Nevertheless, performance data of CORB score are still scarce for independent prediction of these outcomes, and its performance related to scores such as the CURB-65 is not clear, which is why this study proposes to assess performance of the CORB score compared to the CURB-65 score as a predictor of IMV, vasopressor support, in-hospital mortality, and 30-day mortality.

2. Material and Methods

A retrospective cohort study was carried out in subjects with CAP in the third-level center Clínica Universidad de La Sabana (Chía, Cundinamarca, Colombia). Patients were treated in the emergency department, general ward, or ICUs. Data were collected from January to August 2020, from medical records dated between January 2012 and February 2020.

2.1. Selection Criteria

Inclusion criteria included an age ≥18 years, regardless of the gender; stay in the emergency room (resuscitation, observation room, and transit room), general ward, or ICU (for at least 6 hours); CAP diagnosis according to the ATS guidelines [5, 7]; and clinical records that included information for CORB and CURB-65 scores’ assessment. Patients with acute decompensation of chronic diseases such as exacerbated COPD, previous congenital heart disease or decompensated heart failure, and chronic or acute interstitial lung disease were excluded. Patients whose pneumonia diagnosis changed or was ruled out during hospitalization, whose pneumonia was related to bronchial obstruction, or those who required IMV prior to taking arterial gases were also excluded.

2.2. Variables

The requirement for IMV and vasopressor support, in-hospital death, and 30-day mortality were the outcomes; the composite outcome included the variables of in-hospital mortality, IMV requirement, and vasopressor requirement. In addition, clinical presentation, findings on physical examination, vital signs, FiO₂ and SpO₂ upon admission, comorbidities, laboratory tests results, diagnostic imaging findings (chest X-ray and/or chest CT), and arterial blood gases were considered as independent variables.

With the obtained variables, CURB-65 and CORB were calculated; the latter scores one point for the variables confusion, oxygenation by SpO₂ ≤90%, respiratory rate ≥30 breaths/minute, and blood pressure (systolic blood pressure <90 mmHg or diastolic blood pressure ≤60 mmHg), with a score of ≥2 points being considered as severe pneumonia. In addition, a CORB score was constructed in which the oxygenation assessment of SpO₂ ≤90% was replaced by a SpO₂/FiO₂ ratio <300.

Data were obtained from admission registry and clinical records during entire hospital stay, while 30-day mortality was obtained from the national source of death. In order to reduce transcription biases, medical records were revised by at least two different reviewers, and data were verified by them when they were recorded into the database.

2.3. Sample Size

Sample size estimation in diagnostic test [11] and data from the study by Williams et al. [12] were considered, in which an incidence of in-hospital mortality due to CAP of 12.7% and a performance for this outcome of the CORB score ≥2 points of 78% for sensitivity and 40% for specificity were reported. For a confidence level of 95% and a precision level of 7%, a minimum total of 1,060 subjects were required. Patients who did not meet the eligibility criteria were replaced until the sample size was completed.

2.4. Statistical Analysis

Data were compiled in the electronic data capture software Research Electronic Data Capture (REDCap) [13] and later downloaded to a spreadsheet to perform the final analysis in the licensed in STATA 14 and SPSS 25 program. Qualitative variables were reported in frequencies and percentages, while quantitative variables were summarized in median and interquartile ranges if their distribution was normal in mean and standard deviation and if their distribution did not meet normality parameters. A bivariate analysis was performed comparing the quantitative variables with Student’s t or Mann–Whitney U test according to their distribution, whereas the qualitative variables were compared using the Chi-square test. By using the scores obtained from CURB-65 and two CORB scores (one score with SpO₂ and another one with the SpO₂/FiO₂ ratio as oxygenation parameters), the respective areas under the ROC curve (AUC-ROC), sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (LR+), and negative likelihood ratio (LR−) with their respective 95% confidence intervals were determined. The association strength of each variable of the studied scores regarding the proposed outcomes was estimated by calculating the odds ratio (OR) and adjusted odds ratio (AOR) using a logistic regression model. The ACORs of the different scores were compared with the DeLong test. For the estimates, a value <0,05 was considered significant.

2.5. Ethical Considerations

This study was approved by the research committee of the Universidad de La Sabana and the institutional ethics committee of the Clínica Universidad de La Sabana, as registered on Act Minute No 526 of January 29, 2021.

3. Results

1,811 subjects were admitted to the final analysis; 15.1% (273/1,811) died in hospital care, 8.78% (159/1,811) required IMV, and 9.77% (177/1,811) required vasopressor support. 25.7% (471/1,811) subjects had a CORB score ≥2 points; the flow of study subjects’ entry is described in Figure 1.

3.1. Population Characteristics

The mean age of the patients was 72.89 years (SD ± 17.09); 56.6% (1,025/1,811) were male. The most frequent symptom was cough in 85.8% (1,554/1,811). The most prevalent comorbidity was high blood pressure in 63.1% (1,142/1,811), and multi-lobar involvement was observed in 30.1% (545/1,811) of the patients. Significant relationship was found for mortality outcome with age: 80.3 vs. 71.6 years ; presence of dyspnea: 82.4% (225/273) vs. 75.8% (1,166/1,538) (p = 0.017); presence of rales: 72.5% (198/273) vs. 64.5% (992/1,538) (p = 0,010); presence of retractions: 54.6% (149/273) vs. 30.6% (471/1,538) ; history of high blood pressure: 72.5% (198/273) vs. 61.4% (944/1,538) ; chronic heart failure: 31.5% (86/273) vs. 20% (308/1,538) ; and dementia: 34.8% (95/273) vs. 13.6% (209/1,538) . Table 1 summarizes other general characteristics of the population.

Calculated odds ratios for each variable belonging to the CORB and CURB-65 scores were different and dependent on whether the assessed outcome was mortality, requirement for IMV, or requirement for vasopressor support. In the case of in-hospital mortality, the OR for confusion was 4.1 (95% CI: 3,114–5,527; ) and when 30-day mortality was evaluated, the OR was 1,4 (95% CI: 1,262–1,505; ); the OR for IMV was 3,1 (95% CI: 2,142–4,348; ) and for vasopressor support was 2,8 (95% CI: 2–3,967; ).

The variables with the highest OR for mortality outcomes were altered state of consciousness and impaired oxygenation with SpO₂/FiO₂ <300 (confusion OR = 4.1; 95% CI: 3,114–5,527; for in-hospital mortality. OR = 1.4; 95% CI: 1,262–1,505; for 30-day mortality. SpO₂/FiO₂ <300 OR = 4.2; 95% CI: 3,136–5,622; for in-hospital mortality. OR = 1.4; 95% CI: 1,249–1,496; for 30-day mortality). Variables with the highest OR for the outcome of IMV and vasopressor support were RR ≥ 30 rpm and oxygenation by SpO₂/FiO₂ <300. The OR and adjusted OR for each of the different score variables and outcomes of interest are shown in Supplementary File 1.

The dichotomous scoring on the CURB-65 and CORB scales was statistically significant for all outcomes; however, in the IMV and vasopressor support requirement outcomes, when SpO₂ ≤ 90% is replaced by SpO₂/FiO₂ <300 in the CORB score, the OR is higher (OR of 2,7 and OR of 2,8 with CORB and SpO₂ ≤ 90% for IMV and vasopressor support vs. OR of 5,0 and OR of 4,3 with CORB and SpO₂/FiO2 <300, respectively). The OR for composite outcomes of CURB-65, CORB >2, and CORB >2 (SpO₂/FiO2 < 300) is shown in Table 2.

3.2. CORB and CURB-65 Scores’ Performance for Mortality, IMV Requirement, and Vasopressor Support Requirement

The AUC-ROC of the CURB-65 score for in-hospital and 30-day mortality was 0,727 (95% CI: 0,695–0,759; ) and 0,726 (95% CI: 0,695–0,756; ), respectively, while the AUC-ROC of the CORB score with SpO₂ ≤90% for in-hospital and 30-day mortality was 0,660 (95% CI: 0,623–0,697; ) and 0,657 (95% CI: 0,621–0,692; ), with DeLong test .

For the outcomes of vasopressor support and IMV, the CURB-65 showed AUC-ROC of 0,608 (95% CI: 0,562–0,654; ) and 0,587 (95% CI: 0,538–0,637; ) respectively, while the CORB showed an AUC-ROC of 0,635 (95% CI: 0,589–0,681; ) for vasopressor support and an AUC-ROC of 0,637 (95% CI: 0,589–0,685; ) for IMV, with DeLong test . When the SpO₂ ≤90% is replaced by SpO₂/FiO₂ <300 in the CORB score, the AUC-ROC improves for predicting the requirement for vasopressor support and IMV, with AUC-ROC of 0,700 (95% CI: 0,654–0,746; ) and AUC-ROC of 0,702 (95% CI: 0,66–0,745; ), respectively. The AUC-ROC of the CORB score that uses SpO₂/FiO₂ <300 exceeds the CURB-65 score by 0,09 and 0,11 points for the outcomes of vasopressor support and IMV, respectively, with DeLong test .

Sensitivity for mortality, IMV, and vasopressor support outcomes was higher for CURB-65. Specificity was higher for CORB with SpO₂ ≤90% for in-hospital and 30-day mortality outcomes; however, when the CORB is used with SpO₂/FiO₂ <300 in its score, specificity improves for vasopressor support and IMV outcomes. In composite results, high sensitivity was found in the CORB ≥2 (SpO₂/FiO₂ <300) with 91.3% and specificity in the CURB-65 > 2 with 77.9%. Table 3 and Figure 2 show the complete performance results for each of the CORB scores (with SpO₂ ≤90% and with SpO₂/FiO₂ <300) and CURB-65 regarding in-hospital mortality, 30-day mortality, and requirement for vasopressor support and IMV outcomes and composite outcomes.

(a)

(b)

(c)

(d)

(e)

Figure 2

Comparison of performance between CORB score, CORB score with SpO₂/FiO₂ and CURB-65 (values correspond to the area under the receiver operating characteristic curve-AUC) estimated in Table 3. (a) In-hospital mortality. (b) 30-day mortality. (c) Vasopressor requirement. (d) Mechanical ventilation requirement. (e) Composite outcome (in-hospital mortality/IMV requirement/vasopressor requirement). AUC: area under the receiver operating characteristics curve. CORB: confusion (new onset or deterioration of preexisting condition), oxygen saturation ≤90%, respiratory rate ≥30/min, and systolic blood pressure <90 mmHg or diastolic blood pressure ≤60 mmHg. CURB-65: confusion, urea nitrogen >7 mmol/L (19 mg/dL), respiratory rate ≥30/min, systolic blood pressure <90 mmHg or diastolic blood pressure ≤60 mmHg, and age ≥65 years. FiO2: fraction of inspired oxygen. SpO₂: oxygen saturation by pulse oximetry. SpO₂/FiO₂: oxygen saturation by pulse oximetry/fraction of inspired oxygen ratio.

4. Discussion

It was found that the CORB score presents a good performance as a predictor of IMV and vasopressor support requirement, being superior to CURB-65 in estimating these outcomes. In the evaluation of in-hospital and 30-day mortality, CURB-65 shows higher performance than CORB calculated with SpO₂ ≤90% and CORB calculated with SpO₂/FiO₂ <300. On the other hand, replacing the oxygenation parameter of SpO₂ ≤90% of the CORB score with the SpO₂/FiO₂ <300 index turns out to be superior in the prediction of outcomes in pneumonia.

The inclusion of oxygenation parameters in the CORB score improves the performance for the prediction of IMV compared to the CURB-65. In addition, it is necessary to clarify that the CURB-65 was designed to predict only 30-day mortality, not other outcomes such as the need for IMV or vasopressors [8]. The measurement of oxygen saturation, through pulse oximetry or by calculating the SpO₂/FiO₂ index, has been correlated with different degrees of hypoxemia in the patients with pneumonia [14, 15]. In the context of acute respiratory failure and adult respiratory distress syndrome (ARDS), PaO₂/FiO₂ represents one of the most important physiological variables for determining the degree of lung injury [16], and it is also a severity benchmark for defining severe pneumonia [5]. In an observational study carried out by Luna et al. which included 63 patients with ventilator-associated pneumonia, it was found that PaO₂/FiO₂ was the factor with the greatest discrimination to predict short-term survival [17]. Regarding the particular case of pneumonia at high altitude, Martínez et al. argued that the measurement of oxygenation through D(A-a)O₂ and PaO²/FiO² of arterial gases showed the best discrimination capacity for IMV at 2,600 meters above sea level [18].

In a multivariate analysis, Buising et al. found that the urea level and age ≥65 years proposed in CURB-65 were not strongly associated variables for the composite outcome of death, IMV, or vasopressor support (OR = 1.71; 95% CI: 0.82–3,58; OR = 0.52; 95% CI: 0,23–1,16, respectively), so the authors proposed to eliminate age and replace urea by SpO₂, which improved the association for prediction of severity by CAP (OR = 3,49; 95% CI: 1,77–6,89) [10], results that are similar to those reported in our study where oxygenation levels were more associated with the requirement for IMV and vasopressor support. Removing the variable associated with age ≥65 years can reduce the misperception that some scores may present with the mortality outcome, decreases the possibility of obtaining higher scores for patients with advanced age who are not comorbid, and reduces the proportion of low scores in younger patients with severe CAP pictures when incorporating a variable correlated with different degrees of hypoxemia. Moreover, excluding the age variable may favor the use of the CORB score in the daily evolution of the patient, since this score would be entirely composed of variables that can change rapidly.

Babu et al. analyzed if the noninvasive index SpO₂/FiO₂ ratio could replace invasive index PaO₂/FiO₂ in all modes of oxygen supplementation in acute hypoxemic respiratory failure; a total of 300 patients were included in this study [19]. In the result, a strong positive linear correlation was noted between PF ratio and SF ratio (r = 0,66; ). Moreover, SF values are 285 and 323 corresponding to PF ratios of 200 and 300 with a sensitivity and specificity of 70 to 80%, respectively. Similar data were found in the study carried out by Pandharipande et al. calculating the respiratory parameter of the SOFA score with noninvasive index SpO₂/FiO₂ and index PaO₂/FiO₂ with a strong positive correlation [20]. Currently, SpO₂/FiO₂ is a diagnostic tool for the early recognition of respiratory failure and the need for IVM, because the pulse oximeter is simple, inexpensive, and available for continuous monitoring of saturation.

Replacing SpO₂ <90% with SpO₂/FiO₂ <300 ratio in CORB score significantly improves the AUC-ROC for pneumonia outcomes. Some authors suggest assessing oxygenation status through indices including FiO₂ since they have shown good prediction of mortality in ARDS [21]. The persistent decrease of PaO₂/FiO₂ is related to significant alveolar involvement in patients with pneumonia as well as to the progression to ARDS; PaO₂/FiO₂ values less than 150 have been associated with a worse prognosis [22]. Arterial blood gas measurement is the gold standard for oxygenation assessment; however, it is an invasive, time-consuming, and uncomfortable procedure for patients. Considering these difficulties, the use of indices from pulse oximetry may be a valid alternative; SpO₂/FiO₂ has shown a reliable correlation with the PaO₂/FiO₂ index [23]. A SpO₂/FiO₂ ratio of 235–315 is equivalent to PaO₂/FiO₂ levels of 200–300 [23]; the SpO₂/FiO₂ <300 would be equivalent to moderate or severe hypoxemia, a parameter that is considered a minor criterion for pneumonia according to ATS/IDSA [5, 7].

This study has several limitations. It is a single-center study, which could restrain its generalizability, although the good sample size supports the results. In addition, subjects older than 18 years were enrolled, which restricts its applicability in younger groups, but adult population included is considered representative. Moreover, since it is a retrospective study, the quality of the information may be affected in the completion of the medical records, but the reduction of the transcription bias could be achieved by the verification carried out by at least two study investigators in charge of corroborating the data obtained from the clinical records. Furthermore, an altitude of 2,640 m.a.s.l. at which the cohort was evaluated could be considered a limitation to the generalization of the results due to acclimatization phenomena [24, 25]. However, there are no significant variations in the results compared to previous studies carried out at sea level [10]. Prospective studies are required to corroborate the performance of the CORB scale with the modification of the oxygenation parameter.

5. Conclusions

The CORB scale for pneumonia proves to have a good performance for the prediction of IMV and vasopressor support, with a higher performance when the SpO₂/FiO₂ ratio <300 is used as an oxygenation parameter. Finally, when compared to the CURB-65 scale, the CORB scale is not superior in predicting mortality.

Abbreviations

AUC:	Area under the curve of receiver operating characteristics
CORB:	Confusion (new onset or deterioration of preexisting condition), oxygen saturation ≤90%, respiratory rate ≥30/min, and systolic blood pressure <90 mmHg or diastolic blood pressure ≤60 mmHg
CURB-65:	Confusion, urea nitrogen >7 mmol/L (19 mg/dL), respiratory rate ≥30/min, systolic blood pressure <90 mmHg or diastolic blood pressure ≤60 mmHg, and age ≥65 years
MSL:	Meters above sea level
CAP:	Community-acquired pneumonia
SpO₂:	Oxygen saturation by pulse oximetry
SpO₂/FiO₂:	Oxygen saturation by pulse oximetry/fraction of inspired oxygen ratio
ICU:	Intensive care unit
IMV:	Invasive mechanical ventilation.

Data Availability

Data supporting the findings of this study are in medical records from the research center.

Disclosure

The research did not receive specific funding but was conducted as part of the authors’ employment at the Universidad de La Sabana.

Conflicts of Interest

The authors declare that there are no conflicts of interest regarding the publication of this article.

Authors’ Contributions

Luis F. Reyes, Alirio R. Bastidas, Eduardo Tuta Quintero, Juan S. Frías, Álvaro F. Aguila conceptualized this project, contributed to data collection, analysis, and validation, and wrote the original draft. Karen D. Pedreros, Manuela Herrera, Laura D. Saza, Alejandra P. Nonzoque, Laura E. Bello, Maria D. Hernández, Germán A. Carmona, Anyelinne Jaimes, Silvia M. Ramírez, Natalia Murillo, contributed to data collection, analysis, and validation, and wrote the original draft.

Acknowledgments

The authors are most thankful for the support of the Clínica Universidad de La Sabana. The study was carried out at the Universidad de La Sabana.

Supplementary Materials

Results with risk score variables of in-hospital mortality, 30-day mortality, invasive mechanical ventilation requirement, vasopressor requirement, and composite outcome. (Supplementary Materials)

References

F. W. Arnold, A. M. Reyes Vega, V. Salunkhe et al., “Older adults hospitalized for pneumonia in the United States: incidence, epidemiology, and outcomes,” Journal of the American Geriatrics Society, vol. 68, no. 5, pp. 1007–1014, 2020.
View at: Publisher Site | Google Scholar
K. D. Kochanek, S. L. Murphy, J. Xu, and E. Arias, “Deaths: final data for 2017,” National Vital Statistics System, vol. 68, no. 9, pp. 1–77, 2019.
View at: Google Scholar
GBD 2017 Causes of Death Collaborators, “Global, regional, and national age-sex-specific mortality for 282 causes of death in 195 countries and territories, 1980-2017: a systematic analysis for the Global Burden of Disease Study 2017,” Lancet, vol. 392, no. 10159, pp. 1736–1788, 2018.
View at: Publisher Site | Google Scholar
A. M. Bramley, C. Reed, L. Finelli et al., “Relationship between body mass index and outcomes among hospitalized patients with community-acquired pneumonia,” The Journal of Infectious Diseases, vol. 215, no. 12, pp. 1873–1882, 2017.
View at: Publisher Site | Google Scholar
C. D. Jackson, D. C. Burroughs-Ray, and N. A. Summers, “Clinical guideline highlights for the hospitalist: 2019 american thoracic society/infectious disease society of America update on community-acquired pneumonia,” Journal of Hospital Medicine, vol. 15, no. 12, pp. 743–745, 2020.
View at: Publisher Site | Google Scholar
L. Pereverzeva, F. Uhel, H. Peters Sengers et al., “Association between delay in intensive care unit admission and the host response in patients with community-acquired pneumonia,” Annals of Intensive Care, vol. 11, no. 1, p. 142, 2021.
View at: Publisher Site | Google Scholar
J. P. Metlay, G. W. Waterer, A. C. Long et al., “Diagnosis and treatment of adults with community-acquired pneumonia. an official clinical practice guideline of the American thoracic society and infectious diseases society of America,” American Journal of Respiratory and Critical Care Medicine, vol. 200, no. 7, pp. E45–E67, 2019.
View at: Publisher Site | Google Scholar
W. S. Lim, M. M. van der Eerden, and R. Laing, “Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study,” Thorax, vol. 58, no. 5, pp. 377–382, 2003.
View at: Publisher Site | Google Scholar
P. G. P. Charles, R. Wolfe, M. Whitby et al., “SMART-COP: A tool for predicting the need for intensive respiratory or vasopressor support in community-acquired pneumonia,” Clinical Infectious Diseases, vol. 47, no. 3, pp. 375–384, 2008.
View at: Publisher Site | Google Scholar
K. L. Buising, K. A. Thursky, J. F. Black et al., “Identifying severe community-acquired pneumonia in the emergency department: A simple clinical prediction tool,” Emergency Medicine Australasia, vol. 19, no. 5, pp. 418–426, 2007.
View at: Publisher Site | Google Scholar
N. A. Obuchowski, “Sample size calculations in studies of test accuracy,” Statistical Methods Medicine Research, vol. 7, no. 4, pp. 371–392, 1998.
View at: Publisher Site | Google Scholar
J. M. Williams, J. H. Greenslade, K. H. Chu, A. F. Brown, and J. Lipman, “Utility of community-acquired pneumonia severity scores in guiding disposition from the emergency department: intensive care or short-stay unit?” Emergency Medicine Australasia, vol. 30, no. 4, pp. 538–546, 2018.
View at: Publisher Site | Google Scholar
P. A. Harris, R. Taylor, R. Thielke, J. Payne, N. Gonzalez, and J. G. Conde, “Research electronic data capture (REDCap)-a metadata-driven methodology and workflow process for providing translational research informatics support,” Journal of Biomedical Informatics, vol. 42, no. 2, pp. 377–381, 2009.
View at: Publisher Site | Google Scholar
W. G. Kwack, D. S. Lee, H. Min et al., “Evaluation of the SpO₂/FiO₂ ratio as a predictor of intensive care unit transfers in respiratory ward patients for whom the rapid response system has been activated,” PLoS One, vol. 13, no. 7, pp. e0201632–11, 2018.
View at: Publisher Site | Google Scholar
B. Rochwerg, D. Granton, D. X. Wang et al., “High flow nasal cannula compared with conventional oxygen therapy for acute hypoxemic respiratory failure: a systematic review and meta-analysis,” Intensive Care Medicine, vol. 45, no. 5, pp. 563–572, 2019.
View at: Publisher Site | Google Scholar
G. R. Bernard, A. Artigas, K. L. Brigham et al., American Journal of Respiratory and Critical Care Medicine, vol. 149, no. 3, pp. 818–824, 1994.
View at: Publisher Site
C. M. Luna, D. Blanzaco, M. S. Niederman et al., “Resolution of ventilator-associated pneumonia: prospective evaluation of the clinical pulmonary infection score as an early clinical predictor of outcome,” Critical Care Medicine, vol. 31, no. 3, pp. 676–682, 2003.
View at: Publisher Site | Google Scholar
G. M. Martínez, D. P. Casas, and A. R. Bastidas, “Oxygen indexes as predictors of mechanical ventilation in pneumonia at 2600 meters above sea level,” Acta Medica Colombana, vol. 41, no. 3, pp. 169–175, 2016.
View at: Google Scholar
M. Gowri, K. P. Abhilash, and S. Kandasamy, “Association between SpO₂/FiO₂ ratio and PaO₂/FiO₂ ratio in different modes of oxygen supplementation,” Indian Journal of Critical Care Medicine, vol. 25, no. 9, pp. 1001–1005, 2021.
View at: Publisher Site | Google Scholar
P. P. Pandharipande, A. K. Shintani, H. E. Hagerman et al., “Derivation and validation of Spo₂/Fio₂ ratio to impute for Pao2/Fio2 ratio in the respiratory component of the sequential organ failure assessment score,” Critical Care Medicine, vol. 37, no. 4, pp. 1317–1321, 2009.
View at: Publisher Site | Google Scholar
W. L. Chen, W. T. Lin, S. C. Kung, C. C. Lai, and C. M. Chao, “The value of oxygenation saturation index in predicting the outcomes of patients with acute respiratory distress syndrome,” Journal of Clinical Medicine, vol. 7, no. 8, p. 205, 2018.
View at: Publisher Site | Google Scholar
B. R. O’Driscoll, L. S. Howard, J. Earis, and V. Mak, “BTS guideline for oxygen use in adults in healthcare and emergency settings,” Thorax, vol. 72, no. Suppl 1, ii90 pages, 2017.
View at: Publisher Site | Google Scholar
T. W. Rice, A. P. Wheeler, G. R. Bernard, D. L. Hayden, D. A. Schoenfeld, and L. B. Ware, “Comparison of the SpO₂/FIO₂ ratio and the PaO₂/FIO₂ ratio in patients with acute lung injury or ARDS,” Chest, vol. 132, no. 2, pp. 410–417, 2007.
View at: Publisher Site | Google Scholar
L. G. Moore, “Measuring high-altitude adaptation,” Journal of Applied Physiology, vol. 123, no. 5, pp. 1371–1385, 2017.
View at: Publisher Site | Google Scholar
M. Gonzalez-Garcia, D. Maldonado, M. Barrero, A. Casas, R. Perez-Padilla, and C. A. Torres-Duque, “Arterial blood gases and ventilation at rest by age and sex in an adult Andean population resident at high altitude,” European Journal of Applied Physiology, vol. 120, no. 12, pp. 2729–2736, 2020.
View at: Publisher Site | Google Scholar

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Copyright © 2022 Luis F. Reyes et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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