By Mark Favot, MD, FACEP and Scott Sparks, MD
Ehrman RR, Russell FM, Ansari AH, et al. Can emergency physicians diagnose and correctly classify diastolic dysfunction using bedside echocardiography? Am J Emerg Med. 2015; 33: 1178-1183.
Landesberg G, Gilon D, Meroz Y, et al. Diastolic dysfunction and mortality in severe sepsis and septic shock. Eur Heart J. 2012;33:895-903.
“They are just septic, give them some IV fluids,” said by any admitting physician. These same words are spoken at many hospitals, yet may seem humorous or even laughable by a clinician with point-of-care ultrasound experience. Why not make a positive impact on patient outcomes?
Does diagnosing diastolic dysfunction in severe sepsis prognosticate mortality and what is the emergency physician accuracy in diagnosing diastolic dysfunction? Can we do it and what difference does it make? The two studies discussed here give us some insight.
Landesberg et al, bravely performed a cohort study of 262 intubated patients admitted to an intensive care unit with a diagnosis of severe sepsis or septic shock as defined by the Surviving Sepsis Campaign. During their hospitalization, the patients each had serial TTE performed early in their ICU stay. Each study was performed according to the American Society of Echocardiography (ASE) guidelines to include diastolic measurements. After each TTE, the patient was grouped into 4 categories based on systolic and diastolic function:
Regression analysis was used to determine the strongest mortality predictors. Groups 2, 3 and 4 all had worse survival than group 1 while groups 3 and 4 had worse overall survival than group 2.
Ehrman et al, conducted a prospective, observational trial and attempted to determine EP accuracy in grading diastolic function with limited TTE training, then compared their interpretation to that of a cardiologist certified by the National Board of Echocardiography. They enrolled 62 patients who were primarily male with comorbid CHF, COPD, hypertension, or diabetes. When using ASE guidelines for categorization, the EP had nearly uniform kappa scores for diagnosing Normal or Grade 1 diastolic dysfunction, when reviewed by the cardiologist (the criterion gold standard). The EP was less accurate with Grades 2, 3, or indeterminate categorizations. The sensitivity for the EP diagnosing significant diastolic dysfunction (grades 2 or 3) was 100% (95% CI, 84 to 100), while the specificity was 47% (95% CI, 24-71), +LR 1.89 (95% CI, 1.21-2.96), -LR 0.0 (95% CI, 0 to – infinity). The kappa score between cardiology and EP diastolic interpretation was 0.44 (95% CI, 0.29 – 0.59) which is modest agreement. However, this same interrater variability has been found in previous studies between board certified cardiologists as well. What this helps establish is that the EP may safely rule out diastolic dysfunction as a cause for dyspnea in the ED or ICU patient.
Using the current ASE grading for diastolic dysfunction requires pulsed wave (PW) Doppler at the mitral inflow as well as the pulmonary veins, and also TDI of the septal and lateral annulus to place a patient into one of 4 categories of diastolic function (normal, impaired relaxation, pseudonormal and restrictive). This is impractical for the majority of emergency physicians who incorporate focused echo into their evaluation of critically ill patients. If we extrapolate from the results of the Landesberg study and use e’ as the sole measure of diastolic dysfunction, we are now armed with a more rapid screening tool that any EP who incorporates focused cardiac ultrasound into their practice should be able to adopt quite quickly.
Take home point: Screen with TTE on the undifferentiated ED or ICU dyspneic/hypovolemic patient to evaluate for fluid responsiveness, LV systolic function, acute badness (tamponade, valvular catastrophe), AND for the presence or absence of diastolic dysfunction to help improve the outcome of the patients. They might be more than a little septic and if they have advanced diastolic dysfunction when you begin resuscitating them (e’ <8cm/s) you may be harming them and hastening their demise with overzealous fluid administration.