Skip to main content

Table 3 Parameters associated with weaning success

From: Parameters associated with successful weaning of veno-arterial extracorporeal membrane oxygenation: a systematic review

Parameters

Definition

Reported performance

Advantages (A)/Disadvantages (D)

References

EtCO2

Partial pressure of CO2 in the gas mixture at the end of exhaled breath.

Under constant ventilator settings, its main determinant is transpulmonary flow from the native heart

Higher values at 24 h in weaned patients;

Rapid rise in EtCO2 preceded changes in hemodynamic monitoring and cardiac index;

Increase of ≥ 5 mmHg above previous mean values during two consecutive 12-h periods associated with weaning and preceded native cardiac output recovery.

(A) Noninvasive alternative to thermodilution cardiac catheter;

(D) Elimination of CO2 may depend on pulmonary dead-space, which is increased after CPR, thus reducing ETCO2 level;

(D) May vary with change in ventilator settings.

Naruke 2010 [50], Yoshida[26]

LVEF

Relation between the amount of blood expelled during each cardiac cycle relative to the size of the ventricle

Greater increase (> 5%) in the first 48 h and significant improvement from cannulation to weaning associated with weaning;

LVEF > 20–25% reported before attempting weaning trial.

(A) Direct marker of systolic function;

(D) Load-dependent;

(D) Absolute value at weaning inconsistently predicted weaning success.

Aissaoui 2011 [15], Aissaoui 2012 [52], Aissaoui 2017 [55], Akin [45], Asaumi [29], Colombo [22], Gambaro [57], Mazet [24], Ouazani [54], Pappalardo [9], Sawamura [43], Sugiura [32], Vuthoori [51],Yi [41]

LVOT VTI

Velocity time integral (VTI) of a pulsed wave Doppler in the left ventricular outflow tract (LVOT) is directly proportional to the stroke volume of the native heart

Improvement from cannulation to weaning, values above 8.5 cm at weaning associated with success;

Threshold of 10 cm reported before attempting weaning trials.

(A) Direct marker of systolic function;

(D) Load-dependent.

Aissaoui 2011 [15], Aissaoui 2012 [52], Aissaoui 2017 [55], Colombo [22], Frederiksen [56], Gambaro [57], Gonzalez Martin [27], Lim [48], Mongkolpun [36], Ouazani [54], Sawada [40], Sawamura [43], Yi [41]

TDI

Tissue Doppler velocity imaging (TDI) is a signal which correlates with myocardial motion. TDI is placed on mitral/tricuspid annulus to evaluate longitudinal systolic function

Mitral systolic velocities (Sa) higher in weaned patients both at maximal and minimal (> 6 cm/s) VA-ECMO flow;

Any improvement in lateral mitral e' velocity and/or > 10% improvement in tricuspid annular S′ velocity during flow reduction trial is an independent predictor of weaning success.

(A) Load-independent, making it useful to guide the weaning process;

(A) Better predictive performance than conventional parameters for weaning success;

(D) Angle-dependent for valid measurement, interobserver variability.

Aissaoui 2011 [15], Aissaoui 2012 [52], Frederiksen [56], Mork [25], Ouazani [54], Yi [41]

TAPSE

Tricuspid Annular Plane Systolic Excursion (TAPSE) is a M-mode derived marker of longitudinal right ventricular function

Higher at full flow (15 mm) in succesfully weaned patients.

(D) Limited data;

(D) Angle dependency.

Frederiksen [56], Mork [25]

RVEF

Relation between the amount of blood expelled during each cardiac cycle relative to the size of the ventricle

3D derived RVEF > 24.6% at first intent of decannulation associated with weaning;

Higher RVEF in patients without ventricular interdependence during weaning trial.

(A) Direct marker of systolic function;

(D) Load-dependent;

(D) 3D Echo is time consuming and  requires offline analysis without immediate assessment;

(D) Two-dimensional measurement less reliable

Aissaoui 2017 [55], Huang [61]

Ventricular interdependence (VI)

Phenomenon whereby the function of one ventricle is altered by changes in the filling of the other ventricle

Absence of VI (Dep-) on the last day before weaning predicted successful weaning.

(A) Highlight ventricular response to load variation.

Aissaoui 2017 [55]