Evaluation of inflammatory biomarkers affecting mortality in acute cholecystitis in the emergency department.

OBJECTIVES: The aim of this study was to investigate the effectiveness of pan-immune inflammation value (PIV), systemic immune-inflammatory index (SII), and systemic inflammation response index (SIRI) in predicting mortality in acute cholecystitis (AC). BACKGROUND: Abdominal pain is one of the most frequent complaints encountered by physicians at emergency department (ED). METHODS: This clinical study is a cross-sectional study among patients admitted to the emergency department of a tertiary hospital and diagnosed with AC. Total survival curves were estimated by the Kaplan‒Meier method. Differences according to risk groups were determined by the log-rank test. RESULTS: A total of 789 patients (survival: 737, non-survival: 52) diagnosed with AC were enrolled in the study. NLR and SII had an excellent diagnostic power in predicting 30-day mortality in the receiver operating characteristic (ROC) analysis, while the diagnostic power of SIRI and PIV was acceptable. It was observed that the probability of survival period decreased in the presence of NLR (>11.07), SII (>2315.18), SIRI (>6.55), and PIV (>1581.13) above the cut-off levels. The HRs of NLR, SII, SIRI, and PIV were 10.52, 7.44, 6.34, and 5.6, respectively. CONCLUSION: NLR, SII, SIRI, and PIV may be useful markers in predicting 30-day mortality in patients with AC (Tab. 3, Fig. 5, Ref. 25).

The Association Between Hyponatremia and Optic Nerve Sheath Diameter: A Prospective Study.

Background Hyponatremia is a common electrolyte balance disorder. It may result in brain edema and increased intracranial pressure (ICP). Optic nerve sheath diameter (ONSD) measurement remains an increasingly sought-after method in many situations associated with ICP elevations. The aim of our study was to investigate the relationship between the change of ONSD before and after hypertonic saline (3% sodium chloride) treatment and the clinical improvement with increased sodium levels in patients with symptomatic hyponatremia who presented to the emergency department. Methodology This study was conducted in the emergency department of a tertiary hospital, according to the design of a prospective, self-controlled, non-randomized trial study. Determined by power analysis, 60 patients were included in the study. The statistical analysis of the continuous data was performed using the means, standard deviations, and minimum and maximum values of the feature values. The frequency and percentage values were used to define categorical variables. The mean difference comparison of pre-and post-treatment measurements was evaluated by paired t-test. P<0.05 was considered to be significant. Results The measurement parameters' differences before and after hypertonic saline treatment were evaluated. While the mean of the right eye ONSD was 5.27±0.22 mm before treatment, it declined substantially to 4.52±0.24 mm after treatment (p<0.001). It was also found that the left eye ONSD was 5.26±0.23 mm before the treatment and declined to 4.53±0.24 mm after the treatment (p<0.001). In addition, the mean of the overall ONSD was 5.26±0.23 mm before treatment and 4.52±0.24 mm after treatment (p<0.001). Conclusions Ultrasonic measurement of ONSD can be used to monitor the clinical improvement of patients receiving hypertonic saline therapy for symptomatic hyponatremia.

Relation between partial arterial carbon dioxide pressure and pH value and optic nerve sheath diameter: a prospective self-controlled non-randomized trial study.

OBJECTIVE: This study aims to determine if there is a correlation between differences in optic nerve sheath diameter (ONSD) and changes in PaCO2 and pH values that were measured in the arterial blood gas (ABG) before and after treatment in COPD patients with acute hypercarbic respiratory failure (AHRF). MATERIALS AND METHODS: This study serves as a prospective self-controlled non-randomized trial study conducted in the emergency clinic of a tertiary hospital. Forty-four patients with COPD, who were found to have acidosis and hypercarbia in ABG and had an indication for non-invasive mechanic ventilation (NIMV), were analyzed prospectively. Demographic information, vital findings, initial ABG values, the ONSD measurement (before the NIMV treatment), consciousness state, and the ABG results obtained in the second hour of the monitoring and the ONSD measurement (after the NIMV treatment) were recorded. RESULTS: In this study, 13 (29.5%) of the patients were female and 31 (70.5%) were male. The age distribution was evaluated as 68.3 ± 9.2 years; the minimum age was 54 and the maximum was 91. A high level of positively significant correlation was found between the mean ONSD and PaCO2 (p < 0.0001). There is a high fit (0.72) between the mean ONSD and PaCO2. A moderate level of negatively significant correlation was found between the mean ONSD and the pH (p < 0.0001). However, there is an insignificant low fit (0.32) between the mean ONSD and the pH. CONCLUSION: The ONSD changed significantly and in a highly correlated manner to acute changes in PaCO2 levels.

Diagnostic value of end-tidal carbon dioxide in the differential diagnosis of unstable angina and non-cardiac chest pain.

OBJECTIVE: This study aims to investigate the diagnostic value of End-tidal carbon dioxide (ETCO2) measured non-invasively at the bedside in order to distinguish between unstable angina pectoris (UAP) and non-cardiac chest pain among patients who present to the emergency department with chest pain without a history of cardiac pathology. MATERIAL AND METHODS: This clinical study is a prospective case-control study among patients presenting to the emergency department of a tertiary hospital with chest pain. After evaluating the inclusion and exclusion criteria, the patients were divided into two groups: 62 patients with UAP and 62 patients with non-cardiac chest pain. Receiver Operating Characteristic (ROC) analysis was used to determine the cut-off in diagnostic value measurements. For UAP prediction, the odds ratio of ETCO2 (including 95% confidence intervals) was calculated using univariate with binary logistic regression analysis. RESULTS: ETCO2 had an excellent diagnostic power in detecting UAP, with 35 cut-offs determined (AUC: 0.84, 95% Cl: 0.76-0.90, p < 0.001). When ETCO2, which affects both non-cardiac chest pain and UAP, is evaluated, an ETCO2 of <35 is statistically significant and 9.74 times more common among UAP patients than patients with non-cardiac chest pain. CONCLUSION: ETCO2, a non-invasive parameter that can be measured immediately at the bedside, may be proposed as a potential biomarker for differentiating patients with UAP from those with non-cardiac chest pain.

The Utilization of Activated Charcoal in the Management of Anaphylaxis: A Case Series.

Anaphylaxis is a sudden onset of systemic hypersensitivity caused by mast cell and basophil degranulation. Food, Hymenoptera venom, and drug allergy are among the leading causes of anaphylaxis, particularly in adults. We can consider anaphylaxis caused by swallowing food or medication as a form of poisoning. Because in anaphylaxis, just like in poisoning, an allergen entering the body poses a life-threatening risk. Therefore, the allergen should be removed from the digestive system immediately. However, the decontamination of the gastrointestinal tract is not routinely used to prevent further absorption of allergens from the intestine into the systemic circulation. Among the gastrointestinal decontamination methods is the use of activated charcoal. In this article, we present four patients who developed anaphylaxis due to drug and food intake and were administered oral activated charcoal after their primary treatment (on average, 15-45 minutes after the first presentation) was completed. The youngest of the patients was 22 years old, and the oldest was 40. No side effects, prolonged anaphylactic state, and biphasic reactions were observed in the follow-up of the patients. All patients were discharged after 48-72 hours of hospitalization. The routine approach to poisoning treatment includes patient stabilization, toxidrome recognition, antidote administration, and supportive care, as well as measures to enhance toxin elimination. In anaphylaxis caused by oral allergens, the substance that initiates the reaction can be compared to a kind of toxin. Eliminating the allergen and reducing its absorption could be achieved by administering activated charcoal. Activated charcoal should be considered adjunctive therapy in treating food and oral drug-induced anaphylaxis. This treatment, when administered in a timely manner, might prevent the development of biphasic reactions and the prolongation of the allergic process in anaphylaxis.

Ultrasonographically detected hepatosteatosis independently predicts the presence and severity of coronary artery disease.

Background: Nonalcoholic fatty liver disease (NAFLD) has shown to be associated with coronary artery disease (CAD). Objectives: The aim of our study was to evaluate the association between the presence and severity of CAD and NAFLD. Methods: The study group consisted of 153 patients who underwent coronary angiographies. Patients were categorized into CAD and non-CAD groups. CAD severity was determined by the number of CAD-involved arteries and the vessel score multiplied by Gensini score, the latter judging CAD severity. Fatty liver was diagnosed by abdominal ultrasonography (USG), with the patients being categorized by the degree of hepatosteatosis, as Grade 0, Grade 1, and Grade 2-3. Results: Among the whole study population, 47.1% of patients (n=72) were female and 52.9% of patients (n=81) were male. Forty-three patients had normal coronary arteries; 27 patients had non-critical CAD and side branch disease; and 83 patients had clinically significant CAD (stenosis>50%). The rate of CAD and Gensini score were significantly different between Grade 0, 1 and 2-3 hepatosteatosis groups (p<0.05). Patients with CAD had a significantly higher AST level than those without (p< 0.05). Conclusions: Ultrasonographically detected hepatosteatosis independently predicts the presence and severity of CAD.

Diagnostic value of monocyte-lymphocyte ratio and red cell distribution width- lymphocyte ratio against other biomarkers in children with acute appendicitis, cross-sectional study.

Our study aims to ascertain the diagnostic value of the Monocyte-lymphocyte ratio (MLR) and red cell distribution width (RDW)-lymphocyte ratio (RLR) by comparing them with other biomarkers in distinguishing patients with and without acute appendicitis (AA). A total of 223 children were recruited in the study conducted according to the Cross-Sectional Study design. Patients under 18 years were assigned to 3 groups; AA, nonspecific abdominal pain (NAP), and a control group. According to the outcome of our research, while C-reactive protein (CRP), white blood cell (WBC), neutrophil count (NEU), neutrophil to lymphocyte ratio (NLR), and MLR had excellent diagnostic power, RLR had acceptable diagnostic power, and platelet to lymphocyte ratio (PLR) had only fair diagnostic power. MLR and NLR, which are simple, inexpensive, and easily accessible parameters, can be recommended to be used together with other biomarkers in diagnosing AA in children.

Assessment of the Diagnostic Value of Novel Biomarkers in Adult Patients With Acute Appendicitis: A Cross-Sectional Study.

Background Acute appendicitis (AA) is one of the most frequent causes of abdominal pain requiring emergency intervention in adults. Approximately one-third of cases present with atypical clinical symptoms. This study aims to compare the monocyte-to-lymphocyte ratio (MLR), red cell distribution width (RDW) to lymphocyte ratio (RLR), and systemic immune inflammation index (SII) with other biomarkers in distinguishing patients with and without AA. Methodology A total of 347 patients (AA 125, nonspecific abdominal pain 90, and control group 132) were enrolled in the study according to the cross-sectional study design. Receiver operating characteristic (ROC) analysis was used to determine the cutoff in diagnostic value measurements. Statistical significance was determined by the statistics of sensitivity, specificity, positive predictive value, and negative predictive value. Comparison of ROC curves of C-reactive protein (CRP), white blood cell (WBC), neutrophil count (NEU), neutrophil-to-lymphocyte ratio (NLR), MLR, and SII was evaluated with the pairwise comparison of ROC curves and 95% confidence interval. Results In detecting AA, CRP, WBC, NEU, NLR, MLR, and SII have excellent diagnostic power (area under the curve [AUC] 0.80-0.88), while RDW, lymphocyte count, monocyte (MON) count, and RLR had acceptable diagnostic power (AUC 0.70-0.77). When the power in the diagnosis of AA was compared, a significant difference was found between CRP and NEU, CRP and SII, WBC and NEU, and WBC and SII. Conclusions The diagnosis of AA remains dependent on many factors. Inflammatory biomarkers assist this process. MLR and SII may be recommended to use in diagnosing AA in adults, along with other clinical findings. RLR is adequate but not superior.

Acute Psychosis in COVID-19: Is It Due to Favipiravir Treatment or Acute Viral Illness?

In this report, we present a case of acute psychosis that occurred after the loading dose of favipiravir, one of the most prescribed antiviral drugs in many countries, in a patient with COVID-19. A 31-year-old female was readmitted to the emergency department after 3 days of sleep disturbance, intermittent paranoid delusions, auditory hallucinations, and agitation that started after the favipiravir treatment was initiated. A physical examination revealed disorganized speech, distorted orientation, and agitation. All laboratory tests, including drug screening and cerebrospinal fluid analysis, were normal. After excluding all the other causes of acute psychosis, favipiravir treatment was discontinued, antipsychotic treatment was started, and the patient was admitted to the psychiatric ward. The symptoms resolved on the second day of hospitalization. Although acute viral illness does seldomly cause psychosis in patients with increased inflammatory response, in the presented case, none of the inflammatory markers were positive, and acute psychosis was attributed to the loading dose of favipiravir. In conclusion, clinicians should be aware of this rare adverse effect and prescribe cautiously to patients at a high risk of psychosis.

Delayed Parosmia Following SARS-CoV-2 Infection: a Rare Late Complication of COVID-19.

In this report, we present two cases of delayed parosmia, a rare complication that occurs in the late period after COVID-19. A 28-year-old male and a 32-year-old female, found to be positive in rRT-PCR tests for SARS-CoV-2, had a loss of taste and smell, respectively. Following the regaining of their ability to smell after 87 and 72 days, respectively, the male patient reported that the smell he perceived felt the smell of burnt rubber, while the female patient stated that it was similar to the smell of onion. As a result of evaluations, a diagnosis of delayed parosmia was made occurring in the late period secondary to SARS-CoV-2 infection. Although anosmia is a common symptom in the early phase of COVID-19, olfactory damage due to Sars-CoV-2 can be persistent, and distorted sense of smell can be prolonged.

Role of Point-of-Care Lung and Inferior Vena Cava Ultrasound in Clinical Decisions for Patients Presenting to the Emergency Department With Symptoms of Acute Decompensated Heart Failure.

OBJECTIVES: This prospective study was performed to evaluate the diagnostic role of point-of-care lung ultrasound (LUS) and inferior vena cava (IVC) ultrasound in patients with acute decompensated heart failure (ADHF). METHODS: A prospective cohort study was conducted between January 2018 and November 2018 on patients with a diagnosis of ADHF in the emergency department (ED). On admission, LUS findings, inspiratory and expiratory IVC diameters, and the inferior vena cava collapsibility index (IVCCI) were obtained. After therapeutic interventions, third-hour changes in LUS and the IVC index and the treatment response were assessed. RESULTS: Eighty patients were enrolled. Forty-six (58%) patients had an ejection fraction (EF) greater than 40%, and 34 (42%) had an EF of less than 40%. Significant differences were detected between the admission and third-hour inspiratory IVC diameter, expiratory IVC diameter, and IVCCI (P = .001). There was no correlation between the EF and inspiratory IVC diameter (r = -0.03; P = .976), expiratory IVC diameter (r = -109; P = .336), or IVCCI (r = -0.72; P = .523) and between the B-type natriuretic peptide level and inspiratory IVC diameter (r = -0.58; P = .610), expiratory IVC diameter (r = -0.33; P = .774), or IVCCI (r = -0.78; P = .493) either. A comparison of admission and third-hour numbers of B-lines on LUS imaging showed a significant decrease in the number of B-lines in all zones at the end of 3 hours (P = .001). A significant difference existed between the hospitalized and discharged patients with respect to IVC diameters and number of B-lines. CONCLUSIONS: In the ED setting, an assessment of B-lines and measurement of IVC diameters are better markers than the B-type natriuretic peptide level, EF, or chest x-ray for diagnosis of ADHF and can be used to make decisions for hospitalization or discharge from the ED.

Effects of Comorbid Factors on Prognosis of Three Different Geriatric Groups with COVID-19 Diagnosis.

Coronavirus disease 2019 (COVID-19) is a new zoonotic infectious disease that was first reported to the World Health Organization (WHO) on December 31, 2019, and declared as a pandemic by WHO on March 11, 2020. Due to the increased incidence of multimorbidity in geriatric age groups, COVID-19 disease leads to more severe consequences in the elderly. We aimed to determine the effects of age, comorbidity factors, symptoms, laboratory findings, and radiological results on prognosis by dividing our patients into 3 different geriatric age groups, using a retrospective descriptive analysis method. Patients included in the retrospective study (n = 483) were divided into the following three different geriatric age groups: young-old (65-74 years), middle-aged (75-84 years), and the oldest-elderly (85 years and over).The length of stay in the intensive care unit of the patients between the ages of 75-84 was higher than the other two groups (p = 0.013). Mortality rates were lowest in patients aged 65-74 years (p < 0.001). The rate of ground glass opacity in thorax CT was higher in patients with mortality (p < 0.001). While the rate of COPD-bronchial asthma was higher in surviving patients (p = 0.001), malignancy (p = 0.005) and cerebrovascular disease (p < 0.001) were higher in patients who died. Patients aged between 75 and 84 (OR: 2.602; 95% CI: 1.306-5.183; p = 0.007) or ≥ 85 (OR: 4.086; 95% CI: 1.687-9.9; p = 0.002) had higher risk for mortality compared to patients aged between 65 and 74. The lowest mortality rates were observed in patients aged 65-74 years. Among the supportive diagnostic methods in 3 different geriatric age groups, PCR positivity has no effect on mortality, while the ground glass opacity on tomography is closely related to the need for intensive care and increased mortality. In patients with COPD-bronchial asthma comorbidity and those with symptoms of fatigue, dry cough, and sore throat, transfer to intensive care and mortality rates were lower, while patients who were transferred to intensive care and who developed mortality had higher malignancy and cerebrovascular disease comorbidities and dyspnea symptoms.

rRT-PCR Results of a Covid-19 Diagnosed Geriatric Patient.

In this study, we aimed to present a geriatric patient with the diagnosis of COVID-19 and with contradictory results in rRT-PCR examinations in short time intervals. A 69-year-old male patient was admitted to the emergency room on the 18th day of May 2020, with the complaints of fever, sweating, myalgia, dry cough that continued for 5 days, and the lack of taste that started on the day he applied to the emergency room. Comorbidity factors include diabetes mellitus, bronchial asthma, and hypertension. The patient has a history of 36 years of smoking 1.5 packs per day. High laboratory findings during hospitalization: monocytes, creatinine, CRP (C-reactive protein). In the thorax CT, in the parenchyma areas of both lungs, there are increases in attenuation with multilobe distributions (more visible at the level of the upper lobes) in the form of ground-glass opacities. May 19, 2020, was subjected to the rRT-PCR test, repeated twice on the 19th of May which also resulted in positive. Despite rRT-PCR tests, which were negative on 27th of May and positive on 28th of May, the patient, whose symptoms disappeared, and general condition improved, was discharged on June 1, 2020, with the recommendation for home isolation. In our case, unlike the incubation period only, we encountered a negative rRT-PCR result on the 8th day after diagnosis. Therefore, the COVID-19 pandemic control and filiation evaluation with the rRT-PCR test may produce false negative results.

Contribution of caval index and ejection fraction estimated by e-point septal separation measured by emergency physicians in the clinical diagnosis of acute heart failure.

OBJECTIVES: Although the reliability of e-point septal separation (EPSS) and caval index (CI) is proven in the diagnosis of acute heart failure (AHF), how much they contribute to the initial clinical impression is unclear. This study aimed to determine the diagnostic contribution of EPSS and CI to the initial clinical impression of AHF. METHODS: This is a prospective observational study conducted in an academic emergency department (ED). The patients admitted to the ED with acute undifferentiated dyspnea were included. Primary diagnosis was made after an initial clinical evaluation, and a secondary diagnosis was made after EPSS and CI measurements. Independent cardiologists made the final diagnosis. The primary outcome was the diagnostic contribution of EPSS and CI to the primary diagnosis. RESULTS: A total of 182 patients were included in the study. The primary diagnosis was found with a sensitivity of 0.55 and specificity of 0.84 and the secondary diagnosis was determined with a sensitivity of 0.78 and specificity of 0.83 in predicting the final diagnosis. The agreement coefficient between the primary and final diagnosis was 0.44 and between the secondary diagnosis and the final diagnosis was 0.61. When the primary diagnosis was coherent with secondary diagnosis, sensitivity and specificity were found to be 0.74 and 0.90, respectively. CONCLUSION: Although a detailed history and physical examination are the essential factors in shaping clinical perception, CI and EPSS combined significantly contribute to the initial clinical impression.

Accuracy of Alvarado, Eskelinen, Ohmann, RIPASA and Tzanakis Scores in Diagnosis of Acute Appendicitis; a Cross-sectional Study.

INTRODUCTION: Many scoring systems have been developed to assist in diagnosis of acute appendicitis (AA). This study aimed to compare the screening performance characteristics of Alvarado, Eskelinen, Ohmann, Raja Isteri Pengiran Anak Saleha (RIPASA), and Tzanakis scores in predicting the need for appendectomy in AA patients. METHODS: Our study prospectively evaluated AA patients that were treated in a tertiary hospital's emergency department. The obtained data were used to calculate Alvarado, Tzanakis, RIPASA, Eskelinen and Ohmann scores. Patients were categorized into two groups according to their histopathological results: positive (PA) and negative appendectomy (NA). The accuracy of different scoring systems in diagnosing AA was investigated. RESULTS: 74 patients suspected to AA with the mean age of 36.68 ± 11.97 years were studied (56.8% male). The diagnosis was histopathologically confirmed in 65 cases (87.8%). Median Alvarado, Tzanakis, RIPASA, Eskelinen and Ohmann scores were significantly higher in patients with positive appendectomy. The area under the curve (AUC), sensitivity, and specificity of Tzanakis score in the cut-off value of 8 were 0.965, 84.4%, and 100%, respectively. For Ohmann and Alvarado scores, these measures were 0.941; 71.9%, 89.9% and 0.938, 60.9%, 89.9%, respectively. Tzanakis scoring system had the best screening performance in detection of cases with AA. CONCLUSION: Tzanakis score is more sensitive and specific than Alvarado, RIPASA, Eskelinen and Ohmann scores in identifying AA patients needing appendectomy.

Concomitant Substance Use Increases the Toxic Effect of synthetic cannabinoid (Bonsai): A Prospective Study.

OBJECTIVE: In this study, we aimed to contribute to the literature by evaluating bonsai and additional drugs. MATERIALS AND METHODS: This prospective study was conducted on 217 patients who admitted to the emergency department (ED) with bonsai intake between December 20, 2014 and January 1, 2016, according to the patient history obtained from the patients. While 168 patients with negative urinary metabolites results were excluded from the study, 49 patients with positive urinary metabolites were included in the study. Patients were divided into two groups. The first group consisted of patients with only bonsai intake and the second group consisted of patients with bonsai and concomitant drug intake. The groups were compared in terms of symptoms, findings, blood gas values, duration of the symptoms, discharge time, hospitalization, and mortality rate. Data were analyzed using the Chi-square, the Fisher's exacttest, the Student t-test, and the Mann-Whitney U test. Data were evaluated at the 95% confidence interval. P<0.05 was considered statistically significant. RESULTS: The mean age of 49 patients included in the study was 26.7±8.9 years and 91.8% (n=45) of the patients were male. Concomittant drug intake was identified in 69.4% of patients. Concomitant drug use was as follows: cocaine (20.4%, n=10), amphetamines (14.3%, n=7), methamphetamines (8,2%, n=4,) tetrahydrocannabinol (32.7%, n=16), opiates (18.4%, n=9) and alcohol (30.6%, n=15). On admission, Glasgow Coma Score (GCS) of the bonsai with additional substance group was significantly higher (p=0,003). The most common symptom was palpitations (tachycardia) (75.5%, n=37). There were no patients hospitalized in Only Bonsai group (p=0,020). The median time to remission of symptoms and median follow-up time of the patients in the emergency room were 3 hours and 6 hours, respectively. Remission time of the symptoms and hospitalization rates were higher in patients with concomittant drug intake (p <0.05) Conclusion: While the bonsai intake alone is not considered mortal to the patients and most of them can be discharged from the ED after signs and symptoms disappear, concomitant drug use can increase the toxic effects of bonsai intake. That is why follow-up of patients taking concomitant drug and the treatment process should be carried out more carefully.

Is Bedside End-Tidal CO2 Measurement a Screening Tool to Exclude Pulmonary Embolism in Emergency Department?

BACKGROUND: Pulmonary embolism (PE) is among the most difficult conditions to diagnose in emergency department. The majority of patients thought to have PE are tested positive for D-dimer and subsequently tested with advanced diagnostic modalities. Novel noninvasive tests capable of excluding PE may obviate the need for advanced imaging tests. We studied the role of combined clinical probability assessment and end-tidal carbon dioxide (ETCO2) measurement for diagnosis of possible PE in emergency department. METHODS: We included 100 consecutive subjects suspected to have PE and a positive D-dimer test to study clinical probability of PE and ETCO2 levels. ETCO2 > 34 mm Hg was found to be the best cut-off point for diagnosing PE. PE was ultimately eliminated or diagnosed by spiral computed tomography (CT). RESULTS: Diagnostic performances of tests were as follows: ETCO2 and D-dimer had a sensitivity of 100% and a negative predictive value (NPV) of 100% at the cut-off levels of 34 mm Hg and 500 ng/mL, respectively; Wells score had a sensitivity of 80% and NPV of 69.7% at a score of 4. CONCLUSIONS: ETCO2 alone cannot reliably exclude PE. Combining it with clinical probability, however, reliably and correctly eliminates or diagnoses PE and prevents further testing to be done.