CHEETAHNon-Invasive Cardiac Output Monitoring

(NICOM)Kanisha BeltKristine Krukar

JP MilleteJohn Ward

ObjectivesWhat is CHEETAH NICOM?

Fluid Optimization

Differential Diagnosis

Drug Titration

How to run the test

Research

Questions

What is CHEETAH NICOM?CHEETAH NICOM is a device that provides continuous, non-invasive, hemodynamic insight, delivering real time tracking of cardiac output and other key hemodynamic parameters.

The hemodynamic feedback provided by CHEETAH NICOM assists healthcare workers with making decisions regarding drug and fluid management and with determining clinical diagnoses.

Settings Where NICOM is Used

ICU

CCU

Anesthesia

Peri-Operative Step Down

Emergency Department

Clinical Applications

Fluid optimization

Hemodynamic differential diagnosis

Drug titration management

Fluid OptimizationTailor fluid management to optimize resuscitation

Hemodynamic monitoring gives nurses information about the patient’s cardiac status and organ perfusion. This allows for the proper fluid intervention(restriction or resuscitation) to be taken.

It aids in making sure that the optimal amount of fluids are being received.

-Suboptimal fluid resuscitation may lead to low perfusion state.

-Overly-aggressive fluid resuscitation can lead to volume overload and heart failure exacerbation.

Drug TitrationInotropes and vasopressors require continuous monitoring. With NICOM, ongoing monitoring in conjunction with repetitive fluid challenges or Passive Leg Raising maneuvers enables objective, tailored management of the patient allowing for the drug dose and type to be changed according to the resulting effects.

Differentiating Diagnoses• By evaluating cardiac output, NICOM is able to aid in differentiating diagnoses with similar symptoms, such as shortness of breath seen with COPD and CHF. NICOM can help determine if the symptom is stemming from a cardiac issue or a pulmonary issue.

• In acute CHF there is no cardiac reserve to propel the additional preload forward therefore there is no increase in cardiac output following the hemodynamic challenge.

• In dyspnea due to COPD the response to the hemodynamic challenge is expected to be positive where the increase in preload causes an increase in cardiac output.

Why is NICOM a better option over other methods of hemodynamic monitoring?

Until the development of NICOM, many hemodynamic parameters were determined via invasive methods

- Pulmonary Artery Catheters allow direct measurement of the cardiac output, stroke volume, pulmonary artery pressures and the mixed venous oxygen saturation. A disadvantage is the difficulty in interpretation of the waveforms and the lack of an understanding of the relevance of each variable obtained. This can lead to inappropriate intervention and adverse results. It is associated with increased mortality (Lavdaniti, 2008).

- Central Venous Pressure can determine whether a patient requires fluids or is well hydrated or even congested. It is dependent on venous return to the heart, right ventricular compliance, peripheral venous tone and posture. A disadvantage is that this method is unable to predict patient’s volume status and response to fluids. It is also invasive and requires insertion of a catheter into the patient’s large neck vein(Lavdaniti, 2008).

Why is NICOM a better option over other methods of hemodynamic monitoring?

- Modified Fick equation is an invasive method of assessing cardiac output from changes in exhaled carbon dioxide during rebreathing. Its major limitation is a time lag of 3 min for a ∼physiological change to be displayed and requirement for mechanical ventilation with constant minute ventilation. The technique assumes no intrapulmonary shunt and requires a correction for estimated shunt fraction (Lavdaniti, 2008).

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What are the Benefits of Using NICOM?

NICOM is completely non-invasive

Reduces the risk of blood borne infections

Provides continuous real-time data

Compact & Portable

Cost Effective

Can be managed by a nurse!

Nursing Research• Background:

• Determining cardiac output in critically ill patients is important in “optimal diagnosis, organ support and definitive management” (Corley, Barnett, Mullany, Fraser, 2009, p. 1292).

• Pulmonary Artery Catheters (PAC) and the Fick equation are currently the common methods to measure CO in critical care units.

• PACs are associated with many risks and do not have a large body of supporting evidence.

• Use of non-invasive hemodynamic monitoring “has the potential to allow the bedside ICU RN to independently measure CO and act on the measures if provided with a structured algorithm to follow” (Corley, Barnett, Mullany, Fraser, 2009, p. 1292).

Nursing Research• Purpose:

to define the learning curve for USCOM use by a non-echocardiograpically trained ICU nurse; and to compare CO measures between USCOM (as determined by the ICU nurse with no previous training in cardiac output assessment) and PAC (as inserted by a medical team), both by thermodilution and a modified Fick equation (Corley, Barnett, Mullany, Fraser, 2009, p. 1292).

Nursing Research• Methods:

• A 2-day training course was provided for the RN conducting the USCOM.

• The USCOM was conducted on 30 patients who were being evaluated for heart failure and/or pulmonary hypertension who also had a PAC.

• After CO was determined by PAC and the Fick equation, CO was determined by use of USCOM.

• The ultrasound beam was directed across either the aortic valve to monitor LV output or the pulmonary valve to measure right ventricular output (Corley, Barnett, Mullany, Fraser, 2009).

Nursing Research• Results:

• “ICC demonstrated very good to excellent correlation for USCOM and PAC, USCOM and Fick and PAC and Fick (r= 0.848, 0.903, 0.921 respectively)” (Corley, Barnett, Mullany, Fraser, 2009, p. 1294).

• Learning curve: “time halved from 22 min to less than 10 min over the course of 30 examinations” (Corley, Barnett, Mullany, Fraser, 2009, p. 1294).

Nursing Research• Discussion:

• There was an unsatisfactory signal in 20% of patients. High failure rate is attributed to “ combination of difficult acoustic environment associated with substantially altered cardiac anatomy and function and the relative inexperience of the operator” (Corley, Barnett, Mullany, Fraser, 2009, p. 1295).

• By the end of the study, average time to obtain USCOM CO was 10 minutes versus 45 – 120 minutes needed to insert PAC.

• USCOM is faster, more cost effective and carries less risk for the patient.

• Limitations: pilot study and small population.

Nursing Research• Nursing Implications:

• “This study has highlighted the fact that appropriately trained ICU RNs can safely and accurately monitor changes in their patient’s CO status in a non-invasive manner with no risk to the patient” (Corley, Barnett, Mullany, Fraser, 2009, p. 1296).

• Increased autonomy for ICU RNs.

NICOM User’s Guide 101

Basic Equipment…

NICOM system is equipped with 4 sensor pads, each of which contains an outer sensor for transmitting a signal, and an inner sensor for receiving returning

signals

Quick “How to” Outline • Perform hand hygiene.• Identify Pt with identifiers based on the hospital’s

protocol.• Monitor patient health status and perform pain

assessment.• Perform patient/family education on the machine and its

purpose.• Assist the patient onto his or her back, with the head of

the bed slightly elevated.• Place the sensors (2 on the upper thorax, 2 below the

lower ribs).• Activate the device • Enter patient-specific characteristics, including name,

height, weight, and gender• Obtain hemodynamic values.• Power off the machine and remove the electrodes from

the patient.• Clean and store the machine.• Perform hand hygiene.• Document.(Ittner, 2012)

Sensor PlacementFirst, shave skin if necessary, wipe with alcohol

Apply the 4 sensors to the patient’s torso in a box-like pattern around the patient’s heart – 2 on the upper thorax, and 2 under the lower ribs

Sensors can be applied to patient’s chest OR back!

Sensor Placement (con’t)

Exact sensor positioning is NOT required

If possible, place the stickers outside of direct contact with ECG electrodes, drains, IV lines, and external pacemaker leads

On a similar note – If performing electrical shock therapy, such as defibrillation or transcutaneous pacing, NICOM should be disconnected

Assessing Hemodynamic Status – The Passive Leg Raising Test (PLR)

When performed on patients in hemodynamic compromise, passive leg raising has been shown to induce changes in cardiac output that reliably predict responsiveness to fluid administration

Performing the PLR Test – Determining a Baseline

• First, have the patient lay in a semi-recumbent position

• Perform a baseline reading

• After confirming baseline reading, NICOM interface will prompt user to initiate PLR challenge…

Performing the PLR Test…

At this time, lay the patient flat and lift their legs above 45o.

Run the PLR challenge test on the NICOM machine

Explanation of the PLR Test

Lifting the legs causes 250 mL of blood from the calf veins to migrate back towards the heart

If it is not possible to lift the patient’s legs, the PLR challenge test is instead performed by administering a 250 mL fluid bolus

PLR ResultsThe PLR Test Report will supply you with valuable hemodynamic information, including…

- Heart rate, BP, MAP

- Cardiac Output (CO)

- Cardiac Index (CI)

- Stroke Volume Index (SVI)

- Other hemodynamic data…

Note the SVI “ (%)”, located on the bottom line

How to Interpret PLR Test ResultsA positive PLR test = ≥ 10% in SVI

A positive PLR test suggests that there is sufficient cardiac reserve to pump an increased preload (which would result from increased fluid administration), thus, the patient would likely be fluid responsive

In such instances, hemodynamic stability could be achieved by nurses with fluid bolus administration, without the use of vasopressor medications

How to Interpret PLR Test ResultsIf the change in SVI is less than 10%, then your patient will likely not be fluid responsive, thus, IV fluid administration will NOT be effective for increasing blood pressure!!!

In the case of a negative PLR test, the nurse should be able to recognize that use of vasopressors will be necessary to maintain hemodynamic stabilization because the patient will not be responsive to fluid bolus administration.

Other Uses for NICOM - Differential Diagnosis

The NICOM PLR challenge test also provides with a simple, and accurate way to help differentiate between different types of shock

- Hypovolemic shock

- Cardiogenic shock

- Neurogenic shock

- Septic shock

Patient/Family Teaching

• Explain the purpose of NICOM in assessing cardiac and tissue perfusion in patients

• Emphasize that NICOM is a painless, noninvasive procedure that can provide valuable information and help guide patient management

Conclusion• Advanced hemodynamic monitoring is an

important part of treatment in clinical situations where aggressive, guided hemodynamic interventions are required to stabilize the patient and optimize outcome

• Cardiac Output and other hemodynamic parameters play an important role in fluid optimization, drug titration, and differential diagnosis, aiding in establishing the right treatment plan and monitoring and refining it in real-time.

References• Cheetah Medical (n.d.). NICOM: 100% noninvasive guided fluid management. Retrieved

from:

http://www.cheetah-medical.com/

• Corley, A., Barnett, A.G., Mullany, D., Fraser, J.F. (2009). Nurse-determined assessment of cardiac

output. Comparing a non-invasive cardiac output device and pulmonary artery catheter: A

prospective observational study. International Journal of Nursing Studies, 46, 1291-1297. doi:

10.1016/j.ijnurstu2009.03.013

• Doig, Drews, & Keefe (2011). Informing the design of hemodynamic monitoring displays. Computers,

Informatics, Nursing, 29, 706-713. doi:10.1097/NCN.0b013e3182148eba

• Ittner, H. (2012). Nursing practice & skill: Cardiac output monitoing, noninvasive: Performing.

• Lavdaniti, M. (2008). Invasive and non-invasive methods for cardiac output measurement.

International Journal of Caring Sciences, 3, 112–117.

Quiz• What are some benefits of CHEETAH

NICOM?

• What bedside maneuver is used to determine if the patient is fluid responsive?

• What are the three main functions of the CHEETAH?