Arterial pH selectively predicts critical care needs in emergency department obese patients with acute dyspnea: A prospective comparative study

Published:April 26, 2018DOI:



      Obese patients with acute dyspnea may be prone to misorientation from the emergency department (ED), due to impaired gas exchange evaluation and altered basal respiratory profiles. This study aims to evaluate the prognostic value of arterial blood pH in obese ED patients with acute dyspnea in comparison to non-obese counterparts.


      Single-center observational study of a cohort of 400 consecutive ED patients with acute dyspnea. The primary endpoint was a composite of Intensive Care Unit admission (with critical care needs) or in ED mortality. Predictors of the primary endpoint were assessed using multivariable logistic regression and ROC curve analysis, in obese (BMI ≥ 30 kg·m−2) and non-obese patients.


      252 patients who had arterial blood gas testing were analyzed including 76 (30%) obese comparable to non-obese in terms of clinical history. 51 patients were admitted to ICU and 2 deceased before admission (20 obese (26%) vs 33 non-obese (19%); p = 0.17). Factors associated with ICU admission were arterial blood pH (pH < 7.36 vs pH ≥ 7.36) and gender. In multivariate models adjusted for risk factors, pH remained the sole independent predictor in obese patients, with no predictive value in non-obese patients (ROC AUC: 0.74, 95% CI [0.60; 0.87], optimal threshold for pH: 7.36, odds ratio: 10.5 [95% CI 3.18; 34.68]).


      Arterial blood pH may selectively predict critical care needs in ED obese patients with acute dyspnea, in comparison to non-obese. A falsely reassuring pH < 7.36 should be regarded as a marker of severity when assessing acute dyspnea in obese ED patients.


      To read this article in full you will need to make a payment
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to The American Journal of Emergency Medicine
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Peters U.
        • Suratt B.T.
        • Bates J.H.T.
        • Dixon A.E.
        Beyond body mass index — obesity and lung disease.
        Chest. 2018 Mar; 153 (Epub 2017 Jul 17): 702-709
        • Jones R.L.
        • Nzekwu M.M.
        The effects of body mass index on lung volumes.
        Chest. 2006; 130: 827-833
        • Barfod C.
        • Lauritzen M.M.
        • Danker J.K.
        • Soletormos G.
        • Forberg J.L.
        • Berlac P.A.
        • et al.
        Abnormal vital signs are strong predictors for intensive care unit admission and in-hospital mortality in adults triaged in the emergency department — a prospective cohort study.
        Scand J Trauma Resusc Emerg Med. 2012; 20: 28
        • Zavorsky G.S.
        • Hoffman S.L.
        Pulmonary gas exchange in the morbidly obese.
        Obes Rev. 2008; 9: 326-339
        • Chalfin D.B.
        • Trzeciak S.
        • Likourezos A.
        • Baumann B.M.
        • Dellinger R.P.
        Impact of delayed transfer of critically ill patients from the emergency department to the intensive care unit.
        Crit Care Med. 2007; 35: 1477-1483
        • Harris S.
        • Singer M.
        • Rowan K.
        • Sanderson C.
        Delay to admission to critical care and mortality among deteriorating ward patients in UK hospitals: a multicentre, prospective, observational cohort study.
        Lancet. 2015; 385: S40
        • Collins S.P.
        • Peacock W.F.
        • Lindsell C.J.
        • Clopton P.
        • Diercks D.B.
        • Hiestand B.
        • et al.
        S3 detection as a diagnostic and prognostic aid in emergency department patients with acute dyspnea.
        Ann Emerg Med. 2009; 53: 748-757
        • Maisel A.
        • Mueller C.
        • Nowak R.M.
        • Peacock W.F.
        • Ponikowski P.
        • Mockel M.
        • et al.
        Midregion prohormone adrenomedullin and prognosis in patients presenting with acute dyspnea: results from the BACH (Biomarkers in Acute Heart Failure) trial.
        J Am Coll Cardiol. 2011; 58: 1057-1067
        • Mockel M.
        • Searle J.
        • Hartmann O.
        • Anker S.D.
        • Peacock W.F.
        • Wu A.H.
        • et al.
        Mid-regional pro-adrenomedullin improves disposition strategies for patients with acute dyspnoea: results from the BACH trial.
        Emerg Med J. 2013; 30: 633-637
        • Alba G.A.
        • Truong Q.A.
        • Gaggin H.K.
        • Gandhi P.U.
        • De Berardinis B.
        • Magrini L.
        • et al.
        Diagnostic and prognostic utility of procalcitonin in patients presenting to the emergency department with dyspnea.
        Am J Med. 2016; 129: 96-104.e7
        • Baggish A.L.
        • Lloyd-Jones D.M.
        • Blatt J.
        • Richards A.M.
        • Lainchbury J.
        • O'Donoghue M.
        • et al.
        A clinical and biochemical score for mortality prediction in patients with acute dyspnoea: derivation, validation and incorporation into a bedside programme.
        Heart. 2008; 94: 1032-1037
      1. Baggish AL, van Kimmenade RR, Januzzi JL, Jr. Amino-terminal pro-B-type natriuretic peptide testing and prognosis in patients with acute dyspnea, including those with acute heart failure. Am J Cardiol 2008;101:49–55.

        • Davis M.
        • Espiner E.A.
        • Yandle T.
        • Richards G.
        • Town I.
        • Neill A.
        • et al.
        Plasma brain natriuretic peptide in assessment of acute dyspnoea.
        The Lancet. 1994; 343: 440-444
        • Januzzi Jr., J.L.
        • Peacock W.F.
        • Maisel A.S.
        • Chae C.U.
        • Jesse R.L.
        • Baggish A.L.
        • et al.
        Measurement of the interleukin family member ST2 in patients with acute dyspnea: results from the PRIDE (Pro-Brain Natriuretic Peptide Investigation of Dyspnea in the Emergency Department) study.
        J Am Coll Cardiol. 2007; 50: 607-613
        • Ray P.
        • Arthaud M.
        • Lefort Y.
        • Birolleau S.
        • Beigelman C.
        • Riou B.
        Usefulness of B-type natriuretic peptide in elderly patients with acute dyspnea.
        Intensive Care Med. 2004; 30: 2230-2236
        • Rehman S.U.
        • Martinez-Rumayor A.
        • Mueller T.
        • Januzzi Jr., J.L.
        Independent and incremental prognostic value of multimarker testing in acute dyspnea: results from the ProBNP Investigation of Dyspnea in the Emergency Department (PRIDE) study.
        Clin Chim Acta. 2008; 392: 41-45
        • Lund N.
        • Gransbo K.
        • Wernersson C.
        • Melander O.
        Cardiometabolic biomarkers are predictors of readmission and death in patients hospitalized for acute dyspnea.
        Am J Emerg Med. 2017; 35: 610-614
        • Lund N.
        • Rohlen A.
        • Simonsson P.
        • Enhorning S.
        • Wessman T.
        • Gransbo K.
        • et al.
        High total carbon dioxide predicts 1-year readmission and death in patients with acute dyspnea.
        Am J Emerg Med. 2015; 33: 1335-1339
        • Eurlings L.W.
        • Sanders-van Wijk S.
        • van Kimmenade R.
        • Osinski A.
        • van Helmond L.
        • Vallinga M.
        • et al.
        Multimarker strategy for short-term risk assessment in patients with dyspnea in the emergency department: the MARKED (Multi mARKer Emergency Dyspnea)-risk score.
        J Am Coll Cardiol. 2012; 60: 1668-1677
        • Bilben B.
        • Grandal L.
        • Sovik S.
        National Early Warning Score (NEWS) as an emergency department predictor of disease severity and 90-day survival in the acutely dyspneic patient — a prospective observational study.
        Scand J Trauma Resusc Emerg Med. 2016; 24: 80
        • Wiklund K.
        • Gransbo K.
        • Lund N.
        • Peyman M.
        • Tegner L.
        • Toni-Bengtsson M.
        • et al.
        Inflammatory biomarkers predicting prognosis in patients with acute dyspnea.
        Am J Emerg Med. 2016; 34: 370-374
        • Zorrilla-Riveiro J.G.
        • Arnau-Bartes A.
        • Rafat-Sellares R.
        • Garcia-Perez D.
        • Mas-Serra A.
        • Fernandez-Fernandez R.
        Nasal flaring as a clinical sign of respiratory acidosis in patients with dyspnea.
        Am J Emerg Med. 2017; 35: 548-553
        • Burri E.
        • Potocki M.
        • Drexler B.
        • Schuetz P.
        • Mebazaa A.
        • Ahlfeld U.
        • et al.
        Value of arterial blood gas analysis in patients with acute dyspnea: an observational study.
        Crit Care. 2011; 15: R145
        • von Elm E.
        • Altman D.G.
        • Egger M.
        • Pocock S.J.
        • Gotzsche P.C.
        • Vandenbroucke J.P.
        The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies.
        PLoS Med. 2007; 4e296
        • Task Force of the American College of Critical Care Medicine, Society of Critical Care Medicine
        Guidelines for intensive care unit admission, discharge, and triage.
        Crit Care Med. 1999; 27: 633-638
        • Dellinger R.P.
        • Levy M.M.
        • Rhodes A.
        • Annane D.
        • Gerlach H.
        • Opal S.M.
        • et al.
        Surviving Sepsis Campaign: international guidelines for management of severe sepsis and septic shock, 2012.
        Intensive Care Med. 2013; 39: 165-228