Less-Invasive Hemodynamic Monitors In The ICU

Transcription

1 Less-Invasive Hemodynamic Monitors In The ICU Andrew M. Luks, MD Assistant Professor Division of Pulmonary & Critical Care Medicine The University of Washington Lung Day June 17, 2011

2 Andrew M. Luks, MD Less-Invasive Hemodynamic Monitors In The ICU DISCLOSURE STATEMENT Dr. Luks has no commercial, non-commercial, or institutional financial interests or personal financial relationships with the tobacco industry to disclose regarding the material presented in this lecture. He has no relationships with manufacturers of the monitoring devices discussed in this lecture This lecture does not include discussion of off-label use of medications

3 An Outline For Today s Talk The rationale for less-invasive hemodynamic monitors The main less-invasive hemodynamic monitoring modalities The data supporting less-invasive hemodynamic monitors Pitfalls of the less-invasive hemodynamic monitoring systems

4 The Rationale For Less- Invasive Hemodynamic Monitors In The ICU

5 PA Catheters May Not Improve Patient Outcomes Primary Outcomes in the Fluid and Catheter Treatment Trial CVC: Central Venous Catheter PAC: Pulmonary Artery Catheter Source: New Engl J Med : 2213

6 PA Catheters Pose Risks To The Patient Risks With Insertion Pneumothorax Ventricular arrhythmia Right bundle branch block Knotting of the catheter Valve damage Risks With Maintenance and Use PA Perforation Pulmonary infarction Thromboembolism Catheter-related blood stream infection PA: Pulmonary Artery

7 We Still Face Important Management Questions Should I give more fluids or go up on the vasopressors?

8 Clinical Criteria Are Often Of No Use

9 The Main Less-Invasive Hemodynamic Monitoring Modalities

10 The Main Less-Invasive Monitoring Modalities S cv O 2 catheters Devices that rely on arterial catheters PiCCO PulseCO / LiDCO FloTrac / Vigelio Doppler techniques Applied Fick principle devices Bioreactance and bioimpedance devices

11 The Principle Behind S cv O 2 Catheters S v O 2 S cv O 2 S a O 2 ScvO2 reflects the balance between tissue oxygen delivery and consumption* Tissues VO 2 * In the upper half of the body

12 Data Output From The Arterial Catheter Systems System Cardiac Output SVV PPV Other PICCO LiDCO GEDV EVLW O 2 Delivery FloTrac None SVV: Stroke Volume Variation; GEDV: Global End-Diastolic Volume; PPV: Pulse Pressure Variation; EVLW: Extravascular Lung Water

13 How These Systems Measure Cardiac Output 1 Dilution techniques: LiDCO (lithium dilution); PICCO (thermodilution) 2 Pulse contour analysis: LiDCO, PICCO and FloTrac Dilution techniques can be used for point measurements or calibration of pulse contour analysis

14 Logistical Issues With Pulse Contour Devices System PICCO LiDCO FloTrac Necessary Equipment Special femoral arterial line; CVC CVC; radial arterial line Arterial line with proprietary transducer Calibration Requirements Stable: q 8 hours Unstable: q 1 hour q 8 hours or with big clinical changes* None * Newer model (LiDCOrapid) does not require calibration CVC: central venous catheter q: every

15 Transesophageal Doppler Techniques Blood flow measured in descending aorta Cross-sectional area of aorta determined by: Nomogram or M-mode echocardiography Cardiac output taken as product of flow and crosssectional area Probe

16 Applied Fick Principle Devices The NICO System Proprietary, rebreathing loop placed in ventilator circuit Induces intermittent partial rebreathing states Differences in elimination of CO 2 between normal and rebreathing states used to estimate PBF PBF assumed to be equal to cardiac output PBF: Pulmonary blood flow

17 Bioimpedance And Bioreactance Devices Bioimpedance: Amplitude Bioreactance: Phase Shift Amplitude Time Changes in amplitude or phase are used to determine cardiac output on a continuous basis

18 The Data Supporting(?) Less-Invasive Hemodynamic Monitoring Devices

19 Correlations Alone Provide Insufficient Information Good correlation and agreement Line of Identity New Method Good correlation; Poor agreement Old Method

20 The Standard Presentation For Data On These Devices Cardiac Output (CO) = CO Device1 - CO Device2 Mean Cardiac Output = [(CO Device1 + CO Device2 ) / 2 ]

21 Important Terminology In This Literature Accuracy: How close the measurement is to the real value Bias: Mean value of the differences in the two measures (low bias = high accuracy) Precision: How close repeated measurements are to each other Limits of agreement: variance around the bias (small variance = high precision)

22 Another View Of The Important Terminology

23 What You Want To See On Bland-Altman Plots Mean of the differences (bias) is near zero (high accuracy) Narrow spread of data points around the bias (high precision) No trend in data points as you move along the x-axis

24 General Comments On The Data About These Devices Large numbers of studies compare devices to PA catheter measurements Studies typically have small numbers of patients Studies are often done in the operating room setting or with specific populations The date of the study is relevant due to changes in device algorithms over time PA: Pulmonary Artery

25 Some Data From Our Typical Patients Source: Spörh et al. Intensive Care Med : 1805 Low bias (high accuracy) but big spread (low precision) Similar pattern seen with PAC vs. pulse contour comparison

26 The Limited Outcome Data For These Devices In adjusted analysis, the choice of monitoring system had no effect on mortality, fluid balance, ventilator and ICU-free days Source: Uchino et al. Crit Care :1

27 Data On Use As Part Of Management Protocols 122 high risk postoperative patients LiDCO used to measure O 2 delivery Monitored for 8 hours Randomized to standard care vs. protocol to achieve target O 2 delivery Source: Pearse et al. Crit Care : R687 EGDT: Early goal directed therapy

28 Data On Use As Part Of Management Protocols Outcome Control EGDT Mean ICU Stay (hours) Mean Hospital Stay (days) * Complications (%) * 28-day Mortality (%) * P < EGDT: Early goal directed therapy Source: Pearse et al. Crit Care : R687

29 Just Because It Works With One Device Hadian et al. Crit Care : 1 17 post-operative cardiac surgery patients 4 hr post-admission monitoring with PAC (TD and CCO), LiDCO, PICCO and FloTrac Findings: Devices displayed similar mean cardiac outputs Trended differently in response to therapies Inter-device agreement varied but improves slightly at lower cardiac outputs TD: thermodilution; CCO: Continuous cardiac output; PAC: Pulmonary artery catheter

30 What About S cv O 2 Catheters? Good correlation with S v O 2 under non-shock conditions * Agreement may not be as good under shock conditions * S cv O 2 and S v O 2 follow similar trends with interventions or changes in condition * Some data to support use as part of management protocols ** Sources: * Marx & Reinhart Curr Opin Crit Care : 263 ** Rivers et al. New Engl J Med : 1368

31 What About The Other Less Invasive Systems? Fewer studies compared to the literature on PICCO, LiDCO and FloTrac Most studies compare these devices to the PAC; few comparisons to other modalities Similar issues with regard to: Study location (i.e., ICU vs. operating room) Study population Age of study PAC: Pulmonary Artery Catheter

32 Pitfalls Of The Less- Invasive Hemodynamic Monitoring Modalities

33 A Big Point To Remember With These Systems Each of the less invasive monitoring systems has important limitations or potential pitfalls of which the system user must be aware Failure to recognize these problems can lead to inappropriate patient care decisions

34 Key Issues For Pulse Contour Analysis Devices No Intra-aortic Balloon Pump No Atrial Fibrillation Good Arterial Waveform

35 Dynamic Parameters Are Useful In Specific Situations Patients must be sedated or paralyzed on mechanical ventilation (no-minimal breath initiation)

36 Curious Statements Seen Throughout The Literature Pulse wave analysis may be limited during periods of hemodynamic instability, thus requiring frequent recalibration of the calibrated systems * and perhaps most troubling is the manufacturer s consideration of shock states as limitations for use ** * Alhashemi et al. Curr Heart Failure Rep : 116 ** Hashim & Lerner Int Anesthesiol Clin : 45

37 Specific Problems With The LiDCO System No CO monitoring in patients on lithium therapy Non-depolarizing muscle relaxants interfere with sensor Never validated in patients with right-toleft shunting CO: Cardiac output Source: Sundar & Panzica Int Anestheiol Clin : 87

38 Complications From PiCCO Arterial Lines Are Low Complication Incidence (%) Hematoma on insertion 4.5 Catheter-related infection 0.8 Ischemia 0.4 Pulse loss 0.4 Femoral artery thrombosis 0.2 Prospective, observational, multi-center study N = 514 Catheters 475 femoral; 26 radial; 9 axillary; 4 brachial Source: Belda et al. Br J Anaesth 2010 Epub

39 S cv O 2 Catheters Have Low Utility In Some Patients 55 year-old man with septic shock Initial S cv O 2 following device calibration The source of the problem: his dialysis fistula (arrow)

40 Potential Problems With The Doppler Systems Assumes a fixed partition of blood flow to cephalic vessels and descending aorta Probe positioning is highly operator dependent Probe position can change unintentionally, limiting accuracy of continuous readings Aortic cross-sectional area is not constant and cannot be estimated from a nomogram Source: Alhashemi et al. Curr Heart Fail Rep : 116

41 Problems With The Fick Principle-Based Systems Shunt physiology increases inaccuracy The patient must be intubated AND on fixed ventilator settings (i.e., no spontaneous breathing)

42 The Take-Home Messages On Less Invasive Hemodynamic Monitors

43 The Key Take-Home Points Less invasive hemodynamic monitors have an inherent appeal The various devices operate based on different principles Data supporting outcome benefits from use of these devices is very limited Each device has pitfalls of which you must be aware The overall treatment protocol may be more important to your patient than the device

44 One Key Message In light of the issues noted in this talk, you are likely not hurting your patient if you are not using these devices in your clinical practice.

45 The End Questions?