Short Topics in Short Topics in Intensive Care MedicineIntensive Care Medicine

OverviewOverview

• Cardiogenic shockCardiogenic shock• Cardiac output monitoringCardiac output monitoring• Haemofiltration & haemodialysisHaemofiltration & haemodialysis• LactateLactate

Cardiogenic Shock in 10 minsCardiogenic Shock in 10 mins

• DefinitionDefinition• IncidenceIncidence• AetiologyAetiology• PathophysiologyPathophysiology• TherapyTherapy

Cardiogenic Shock in 10 minsCardiogenic Shock in 10 mins

• DefinitionDefinition• IncidenceIncidence• AetiologyAetiology• PathophysiologyPathophysiology• TherapyTherapy

Clinical:• Hypotension i.e. SBP below 90 mmHg• Impaired tissue perfusion• After correction of non-cardiac factors

Haemodynamic:• Cardiac index < 2.2 litres/min/m2 • Systolic blood pressure < 90 mm Hg • LAP/RAP > 18 mm Hg or PCWP > 16• Urine output < 20 ml/hr • SVR > 2100 dynes-sec·cm–5

Incidence & MortalityIncidence & Mortality

[1] The CREATE-ECLA Trial Group. Effect of glucose-insulin-potassium infusion on mortality in patients with acute ST-segment elevation myocardial infarction: the CREATE-ECLA Randomized Controlled Trial. JAMA 2005; 293: 437–446.

[2] Babaev A, Frederick PD, Pasta DJ, et al. Trends in management and outcomes of patients with acute myocardial infarction complicated by cardiogenic shock. JAMA 2005; 294:448–454.

[3] Jeger RV, Harkness SM, Ramanathan K, et al. Emergency revascularization in patients with cardiogenic shock on admission: a report from the SHOCK trial and registry. Eur Heart J 2006; 27:664–670.

[4] Chen ZM, Pan HC, Chen YP, et al. Early intravenous then oral metoprolol in 45,852 patients with acute myocardial infarction: randomized placebo controlled trial. Lancet 2005; 366:1622–1632.

Study Incidence Mortality Patient group Country

CREATE-ECLA [1]CREATE-ECLA [1] 6.5%6.5% 68%68% STEMISTEMI China, India, PakistanChina, India, Pakistan

NRMI [2]NRMI [2] 8.6%8.6% 47.9%47.9% STEMISTEMI USAUSA

COMMIT [3]COMMIT [3] 4.4%4.4% 68%68% AMI (93% STEMI)AMI (93% STEMI) ChinaChina

5.0%5.0% 68%68% MetoprololMetoprolol

3.9%3.9% 72%72% PlcaeboPlcaebo

SHOCK [4]SHOCK [4] 20%20% 75%75% CS on admissionCS on admission USA/BelgiumUSA/Belgium

80%80% 56%56% Delayed CSDelayed CS

Echo indicators of mortalityEcho indicators of mortality

Cardiogenic Shock in 10 minsCardiogenic Shock in 10 mins

• DefinitionDefinition• IncidenceIncidence• AetiologyAetiology• PathophysiologyPathophysiology• TherapyTherapy

Cause of CS Cause of CS ProportionProportion

LV failure post-MI (8.5% of STEMI, 2.5% of NSTEMI)

70-75%70-75%

Acute severe mitral regurgitation 8.3%8.3%

Ventricular septal rupture 4.6%4.6%

Isolated RV failure 3.4%3.4%

Ventricular free-wall rupture orCardiac tamponade

1.7%1.7%

Myocardial contusionMyocardial contusion

LVOT obstruction (AS/HOCM)LVOT obstruction (AS/HOCM)

End-stage cardiomyopathyEnd-stage cardiomyopathy

Obstructed LV filling (MS)Obstructed LV filling (MS)

MyocarditisMyocarditis

Cardiogenic Shock PathophysiologyCardiogenic Shock Pathophysiology

Cardiogenic Shock PathophysiologyCardiogenic Shock Pathophysiology

Target for therapy?

At least 20% of CS patients have SIRS and low SVR

TherapyTherapy - Reducing iNOS: L-NMMA - Reducing iNOS: L-NMMA

“Excessive NOS results

in high levels of nitric

oxide that, in turn, lead

to inappropriate systemic

vasodilatation, progressive

systemic and coronary

hypoperfusion, and

myocardial depression”

Effect of Tilarginine Acetate in Patients With Acute Myocardial Infarction and Cardiogenic Shock - The TRIUMPH Randomized Controlled Trial. JAMA 2007;297:1657-1666

Cardiogenic Shock TherapyCardiogenic Shock Therapy• Optimise volume / oxygenation / rhythm• Inotropic agents & vasopressors

agonists a agonists PDE III inhibitors LEVOSIMENDAN

• sensitizes myocardial contractile proteins to calcium

• independent of sympathetic NS and so NO increase in MVO2

• Prolonged action beyond infusion duration

• IABP• PCI

Cardiac Output MonitoringCardiac Output Monitoring

• Oesophageal dopplerOesophageal doppler• Fick-based methods e.g. NICOFick-based methods e.g. NICO• Pulse contour analysisPulse contour analysis• Pulse power analysis e.g. LiDCOPulse power analysis e.g. LiDCO• Impedance cardiography e.g. NICCOMOImpedance cardiography e.g. NICCOMO

Oesophageal DopplerOesophageal Doppler• Measures blood flow velocity in descending aortaMeasures blood flow velocity in descending aorta• Doppler transducer (continuous or pulsed wave)Doppler transducer (continuous or pulsed wave)• Uses VTI x Area (measured with M-mode or estimated)Uses VTI x Area (measured with M-mode or estimated)• Assumptions:Assumptions:

– accurate descending aortic blood flow velocityaccurate descending aortic blood flow velocity– estimated aortic CSA near mean value during systoleestimated aortic CSA near mean value during systole– constant division of flow between descending aorta (70%) and constant division of flow between descending aorta (70%) and

brachiocephalic / coronary arteries (30%)brachiocephalic / coronary arteries (30%)– negligible diastolic flow in the descending aortanegligible diastolic flow in the descending aorta

Limits of agreement between thermodilution and OD = +2 Limits of agreement between thermodilution and OD = +2

l/min to -1.5 l/minl/min to -1.5 l/min

Oesophageal DopplerOesophageal Doppler

NICONICO

Applies Fick principle to COApplies Fick principle to CO22

intermittent partial rebreathing through intermittent partial rebreathing through disposable rebreathing loopdisposable rebreathing loop

ComponentsComponents– COCO22 sensor (infrared light absorption) sensor (infrared light absorption)

– disposable airflow sensor (differential disposable airflow sensor (differential pressure pneumotachometer)pressure pneumotachometer)

– pulse oximeterpulse oximeter

Impedance cardiography – how?Impedance cardiography – how?

An alternating current is An alternating current is transmitted through the chest. transmitted through the chest. The current takes path of The current takes path of least resistance: the blood least resistance: the blood filled aorta. filled aorta. Baseline impedance to current Baseline impedance to current is measured. is measured. Blood volume and velocity in Blood volume and velocity in aorta change with each heartbeat. aorta change with each heartbeat. Corresponding changes in Corresponding changes in impedance are used with ECG to give impedance are used with ECG to give haemodynamic parameters. haemodynamic parameters.

Kubicek NASA 1960 started development of modern equations relating SV to maximum value of the first derivative of the impedance waveform (dZ/dtmax) and the left ventricular ejection time (LVET)

Impedance cardiography – how?Impedance cardiography – how?

Impedance cardiography – what?Impedance cardiography – what?

Stroke Volume/Index (SV/SVI) Stroke Volume/Index (SV/SVI)

Cardiac Output/Index (CO/CI) Cardiac Output/Index (CO/CI)

Systemic Vascular Resistance/Index (SVR/SVRI) Systemic Vascular Resistance/Index (SVR/SVRI)

Velocity Index (VI) Velocity Index (VI)

Thoracic Fluid Content (TFC) Thoracic Fluid Content (TFC)

Systolic Time Ratio (STR) Systolic Time Ratio (STR)

Left Ventricular Ejection Time (LVET) Left Ventricular Ejection Time (LVET)

Pre-Ejection Period (PEP) Pre-Ejection Period (PEP)

Left Cardiac Work/Index (LCW/LCWI) Left Cardiac Work/Index (LCW/LCWI)

Heart Rate Heart Rate