Background: 

For decades, we had been counting on Vital Sign monitoring to diagnose and treat our patients, but vital sign monitoring does not provide us with all the necessary information necessary for quick diagnosis, differential diagnosis, drug titration and better management of our critical patients, for example: flow, resistance, heart contractility, oxygen delivery (DO2) or fluid level in the body (Chart 1).

In addition to the “non-direct” relation between mean arterial pressure (MAP) or heart rate (HR) for example with DO2 (Chart 2) and this explains the late drop in MAP while fluid level in the body had decreased 20 to 30 minutes earlier.

Hemodynamics is the key for perfect patient diagnosis, differential diagnosis and management, but it was always a challenge to obtain hemodynamics, as it used to be obtained typically by using pulmonary artery catheters (Swan Ganz Catheter) or Picco or Edwards Flotrac. However, concerns about the costs, complications, contraindications and difficulty of use (especially in pediatrics and neonates) made us think twice before inserting a catheter into a patient. Today health care requires products and services that are non-invasive, lower the patient risk, cost effective, easy to use, accurate and validated for all age groups

Electrical Cardiometry (EC) is one of the latest noninvasive technique which uses 4 sensors on the patient’s head and neck which send a signal that travels through the patient’s chest and specifically through the thoracic aorta and it detects the changes in blood flow due to RBCs alignment changes, blood velocity and aortic diameter changes (between systole and diastole) beat-to-beat which lead to measuring and calculating a wide range of hemodynamic and cardiac parameters :

Stroke Volume/ Index (SV/SVI)
Cardiac Output/ Index (CO/CI)
Systemic vascular resistance/ Index (SVR/SVRI)
Thoracic fluid content (total extra vascular fluids)
SVV (Fluid Responsiveness and Preload indicator)
Left Cardiac Contractility Indicator (ICON)
Ejection Fraction indicator (STR)
DO2 (Oxygen Delivery)

With the above parameters (Chart 4), we can easily and quickly and in a noninvasive and accurate way have a great idea about 5 major factors in every patient we are treating: Flow, Resistance, Contractility, Fluid level “intra and extra vascular” and Oxygen Delivery.

Briefly speaking, electrical cardiometry (EC) helps physicians to make a quick and correct differential diagnosis in 2 minutes, based on when the medication will start, and not only this, but it also enables follow up of the response of the medications as the beat-to-beat technology allows titration of medications and adjusting the doses of each medication and fluid administration accordingly with virtually no complications and in a very cost effective way.

Validation:

Many published studies and clinical papers showing that the new electrical cardiometry (EC) algorithm is clinically and statistically equivalent to Thermo-dilution, Fick, PiCco, Echo and TE probe. Most of the reproducibility and accuracy studies show that the Electrical Cardiometry (EC) is above 90% in correlation to other techniques in different patient conditions in ICU, CCU, NICU, PICU, O.R. and many in E.R. and also outpatient clinic.

Clinical Applications:

  1. Shock – Differential diagnosis & Management: differential diagnosis of cardiogenic from non-cardiogenic shock has become so easy with EC technology, and if non cardiogenic, determining whether it is septic, hypovolemic or anaphylactic shock has become easy and in 2 minutes (rather than the time and money consuming investigations which we use currently) which in turn saves many lives, even the likelihood of shock could be presented as well (Chart 4) and managing these patients with early recovery and better mortality rate has been proven in many clinical studies.
  2. Fluid Management: Fluid management is very important in many critical patients (neonates, burn, sock, ICU, O.R., infections). Fluid calculation based on urine output, body weight, non-invasive blood pressure (NIBP) is not enough for fluid administration. SVV (stroke volume variation) and FTc (Flow Time Corrected) are perfect indicators for fluid responsiveness and preload, and in turn give very early detection of preload decrease, and prevent dehydration or over hydration in neonates, while TFC (Thoracic fluid) gives us a great idea about extra vascular lung water and tissue fluid.
  3. Hypertension: Only one third of the hypertensive patients are controlled and high blood pressure could be due to high fluids, or high SVR or high contractility. Knowing the reason is not possible by normal clinical examination, but electrical cardiometry helps us to determine the cause of high blood pressure, and hence choose the right treatment rather than trial and error of medications. This will lead to a massive reduction in the cost of treating hypertensive patients, and will reduce heart failure (HF) patients as well.
  4. Heart Failure: is one of the leading causes of death. It is challenging to titrate medications for HF patients especially when we have no idea about CO, SV, SVR, tissue & intravascular fluids and heart contractility. But with electrical cardiometry it is very easy to manage and to titrate medications for these patients (especially inotropes and diuretics).
  5. Predictive Parameters: Complexity Analysis:

EC provides us with heart hate complexity (HRC) and heart rate variability (HRV) which has been shown helping to predict the need for life saving intervention in trauma patients (Boston Marathon Study).

Cost Saving and reduce Length of Stay (LOS):

Using EC in HF patients coming to the ER, can reduce cost of the patients and length of stay by 71% (Milzman D, et al. Ann Emerg. Med, 2008)

Conclusion:

Non-invasive technology, which is very easy to use, reliable, provides continuous hemodynamic data in 2 minutes time which helps in quick diagnosis and differential diagnosis and is a better way to treat all critical patients in different age groups.

 

Yasser Nassef, MD, PhD
Pediatric Cardiologist
Hemodynamic Lecturer/Consultant
PhD. Candidate CS University Taiwan
National Liver Institute Egypt

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