Importance of the left ventricular ejection fraction and of subaortic integral time velocity assessment in the management of hemodynamic shock in emergency patients

key words : the left ventricular ejection fraction - subaortic integral time velocity- hemodynamic shock Introduction: Clinical approach is not often sufficient to determine the hemodynamic etiology of shock treated in... [ view full abstract ]

key words : the left ventricular ejection fraction - subaortic integral time velocity- hemodynamic shock
Introduction: Clinical approach is not often sufficient to determine the hemodynamic etiology of shock treated in emergency departments. Transthoracic echocardiography (TTE) in nowadays more and more used by emergency physicians to determine the hemodynamic origin of shock in patients rushed to emergency departments.
Objective : To assess the importance of a simplified approach of hemodynamic assessment of patients in shock by TTE practised by an emergency physician to evaluate semi-quantitatively the left ventricular ejection fraction (LVEF) and to measure the subaortic integral time velocity (ITV).
Material and methods: This prospective study was carried out in the emergency department over 6 months. It included all patients presenting with systolic blood pressure (bp) < 90 mmHg or mean bp < 60 mmHg and/or peripheral circulatory insufficiency associated with organ dysfunction. All patients underwent TTE practised by a previously trained emergency physician in doppler echocardiography.
Clinical diagnosis and initial treatment were compared to the findings provided by TTE concerning the following criteria : echogenicity of patient, LVEF assessed by a global visual estimation, subaortic ITV measurement by planimetry of aortic flow using pulsed-reflected doppler echography (doppler sample just above the sigmoid valves of aorta) and existence of pericardial effusion.
Results: The study involved 15 patients aged 65.8 + 10 years on overage. Seventy per cent of them were males. Of the patients included in the study, 40% were hypertensives, 45% were diabetics, and 30% were suffering from atrial fibrillation.
Echogenicity was poor in 25% of cases. LVEF was assessable in 90% of cases and ITV was measurable in 85% of cases. Pericardial effusion was noted in 25% of cases with signs of compression in one of them. In 30% of cases the findings provided by TTE led to alterations to the etiologic diagnosis of shock and to the therapeutic approach in 20% of cases. Based on the above mentioned criteria, positive diagnosis was not, however, possible in 5% of cases. Note that 45% of TTE were performed prior to treatment.
Conclusion: Left ventricular ejection fraction and subaortic integral time velocity are useful for a hemodynamic assessment of patients in shock in emergency departments. They may, in some cases, make it possible to rectify a diagnosis but they are not sufficient in complex hemodynamic situations.