Journal of Neurology Research, ISSN 1923-2845 print, 1923-2853 online, Open Access
Article copyright, the authors; Journal compilation copyright, J Neurol Res and Elmer Press Inc
Journal website http://www.neurores.org

Case Report

Volume 6, Number 1, February 2016, pages 28-34

Apnea Testing for the Determination of Brain Death in Patients Supported by Extracorporeal Membrane Oxygenation

Figures

Figure 1.
Figure 1. Illustration of VA ECMO and VV ECMO. Example of the cannulation sites for VA ECMO (femoral vein-femoral artery) and VV ECMO (femoral vein-internal jugular vein) with blood flow through the oxygenator.
Figure 2.
Figure 2. The membrane oxygenator in ECMO. The extracorporeal membrane oxygenation pump delivers venous blood to the oxygenator. This device is divided into two chambers by a semipermeable membrane. The venous blood enters the oxygenator and travels along one side of the membrane (the blood side), while fresh gas known as sweep gas is delivered to the other side (the gas side). Gas exchange (oxygen uptake and carbon dioxide elimination) takes place across the membrane. The oxygenated blood reinfused into the patient’s venous system.
Figure 3.
Figure 3. Steps of performing apnea test in patients on ECMO. Stepwise illustration of performing apnea test to confirm brain death in patients supported by ECMO.

Tables

Table 1. The Standard Initial Settings and Goals for ECMO [15]
 
Circuit flow50 - 80 mL/kg/min
Sweep gas flow50 - 80 mL/kg/min
Fractional inspired oxygen100%
Oxygen saturation (drainage cannula)> 65%
Oxygen saturation (return cannula)100%
Arterial oxygen saturationVA: > 95%; VV: 85-92%
Arterial carbon dioxide tension35 - 45 mm Hg
Mean arterial pressure65 - 95 mm Hg

 

Table 2. Summary of ECMO Settings During Apnea Testing [21-25]
 
ReportCaseInitial ECMO settingsOxygenation methodECMO during testingAncillary testing
Jarrah et al [21]#1Blood flow rate 88 mL/kg/min
Sweep flow rate 0.5 L/min
FiO2 100%		CPAP
FiO2 100%		Blood flow rate 88 mL/kg/min
Sweep flow rate 0.1 L/min
FiO2 100%		None
#2Blood flow rate 38 mL/kg/min
Sweep flow rate 5.5 L/min
FiO2 100%		CPAP
FiO2 100%		Blood flow rate 38 mL/kg/min
Sweep flow rate 1.0 L/min
FiO2 100%		None
#3Blood flow rate 140 mL/kg/min
Sweep flow rate 0.22 L/min
FiO2 100%		CPAP
FiO2 100%		Blood flow rate 140 mL/kg/min
Sweep flow rate 0.1 L/min
FiO2 100%		EEG
Hoskote et al [24]Blood flow rate 4.5 mL/kg/min
Sweep flow rate 6 L/min
FiO2 100%		NoneBlood flow rate 4.5 mL/kg/min
Sweep flow rate 0.5 L/min
FiO2 100%		None
Smilevitch et al [22]Blood flow rate 4.1 mL/kg/min
Sweep flow rate 3 L/min
FiO2 40% increased to 100% during preoxygenation		T-piece 9 L/minBlood flow rate 4.1 mL/kg/min
Sweep flow rate 3 L/min
FiO2 100%		EEG
Goswami et al [25]#1Blood flow rate 5.0 mL/kg/min
Sweep flow rate Not documented
FiO2 100%		Not specifiedBlood flow rate 5.0 mL/kg/min
Sweep flow rate 0.5 L/min
FiO2 100%		EEG
#2Blood flow rate 4.1 mL/kg/min
Sweep flow rate 3 L/min
FiO2 40% increased to 100% during preoxygenation		Not specifiedBlood flow rate 6.0 mL/kg/min
Sweep flow rate 0.5 L/min
FiO2 100%		EEG
Iannuzzi et al [23]Blood flow rate 4.0 mL/kg/min
Sweep flow rate 8 L/min
FiO2 70%		CPAP
FiO2 100%		Blood flow rate 2.0 mL/kg/min
Sweep flow rate 0.5 L/min
FiO2 100%		None