Donation after circulatory determination of death

"Donation after circulatory determination of death" is the name we have currently settled on after "donation after cardiac death",  "donation after circulatory death" and "non-heartbeating organ donation" have receded into history. This mechanism of organ donation has historically been rather underutilized and even now comprises merely 25% of Australia donations, according to the latest ANZICS statement.  This topic has appeared as Question 10 from the second paper of 2022, where the candidates were asked for the process of determination of death, as well as the definition of "functional warm ischaemic time" and some rather detailed information about graft survival rates in DCD recipients. What follows is an attempt to distill the already concise Statement into some kind of pointform summary, so that all future DCCD questions may be covered.

Determination of death

The circulatory determination of death requires "irreversible cessation of circulation of blood in the body of the person". This means:

• Unresponsive
• Not breathing
• Not moving
• Has no pulse (by arterial monitoring, if possible, rather than ECG, though electrical asystole is also acceptable)
• For 5 minutes.
• After 5 minutes, absence of pulse and heart sounds is confirmed by clinical examination.

That last clause is to prevent people from becoming donors when they have in fact "autoresuscitated" after 1-2 minutes, i.e. the circulation spontaneously resumed for a period. 

Functional warm ischaemic time

Question 10 from the second paper of 2022 askes for a definition of "functional warm ischaemic time", which is a term that appears in the ANZICS statement only once. Their definition is:

"The functional warm ischaemic time is the time from when the systolic blood pressure falls below 50 mmHg after withdrawal of cardiorespiratory support to cold perfusion and may be a better measure of ischaemic injury"

Better than what? Better than the agonal period:

"The agonal period is the time from withdrawal of cardiorespiratory support until circulatory arrest. ... It is limited to approximately 90 minutes in Australia and New Zealand so that if death has not occurred within this time frame the donation process is usually aborted"

What is the influence of this on graft function? Well: predictably, a graft that has been poorly perfused for longer will function poorly and may fail. These are times from 

• Kidney: 60 minutes (from when systolic drops to lower than 50 mmHg)
• Liver: 30 minutes (from when systolic drops to lower than 50 mmHg)
• Heart: 30 minutes (from when systolic drops to lower than 90 mmHg)
• Lung: 90 minutes (from when systolic drops to lower than 50 mmHg)
• Pancreas: 30 minutes (from when systolic drops to lower than 50 mmHg)

Because the CICM examiners complained that "knowledge of graft survival between different organs was... commonly incorrect",  a mnemonic of some sort may be called for. LHP30,K60,L90? Everything near the epigastrium 30, kidneys 60, lungs 90? Also, all the organs measure their warm ischaemia time from an SBP of 50 mmHg, whereas for the heart the timer starts from 90 mmHg. This timeline from Donate Life is probably best for people who might prefer to have the warm ischaemia timeframes described visually (with thanks to Dr Simon Wong, who found this): 

Graft survival rates: DCDD vs DNDD

• Kidney:
  • Equal survival rates for recipients (86% at 5 years), whether they get kidneys from a DCDD or a DNDD donor
  • Delayed graft function is more common in the DCDD group, as the graft may be slightly more injured.
• Liver:
  • DCDD recipient survival rates are lower (70-75% at 5 years)
  • Risks of ischaemic cholangiopathy are higher in DCDD 
• Heart:
  • DCDD heart donation is not very well known; most donated hearts come from DNDD donors and graft survival in DCDD is not very well investigated
• Lung:
  • DCDD graft survival rates approach 90% at 5 years and this is close to the results seen with DNDD grafts
• Pancreas:
  • Grafts are still working in 72% of DCDD recipients at 5 years, very similar to DNDD