Optimal depth, timing and duration based on recent clinical trials (K Sunde)
Cardiac arrest is a complex disease
- several different causes (many untreatable, irreversible, extreme challenging)
- large heterogeneity
- challenges the system due to the limited/crucial time-intervals (hypoxia/extreme ischemia)
- large differences in quality of care within and inbetween systems (both during ALS and in post resuscitation care)
- very high mortality
Depth and Timing
ILCOR Statement 2003 –
Unconscious adult patients with spontaneous circulation after out-of hospital cardiac arrest should be cooled to 32-34°C for 12-24 hrs when the initial rhythm was VF.
For any other rhythm, or cardiac arrest inhospital, such cooling may also be beneficial.
- timing, speed and duration of hypothermia had no impact on outcome!
Confounding aspects regarding early/fast cooling
- the lack of protection against a drop in core temperature is due to a larger and deeper brain injury! (link)
- If you are really “dead” you are colder and it is very easy to cool you fast! (link)
Intra-Arrest Transnasal Evaporative Cooling: A Randomized, Prehospital, Multicenter Study (PRINCE: Pre-ROSC IntraNasal Cooling Effectiveness) link
Duration of TTM
- Cardiac arrest is complex, with large heterogeneity and very high mortality
- Large differences in quality of care within and inbetween systems
- Concerning pathophysiology and TTM: depth, speed and duration impacts on the reperfusion injury/brain injury
- We are concluding based on pragmatic trials not optimizing the intervention tested or considering the ongoing pathophysiology!
- Outcome assessment: cognitive function/QoL years after the arrest!
Haemodynamic Management During Targeted Temperature Management (Huang CH)
Multiple reasons for haemodynamic instability post-cardiac arrest
Haemodynamic Response Correlated to Outcome – Reversible myocardial dysfunction in survivors of out-of-hospital cardiac arrest.
Cardiovascular Response & Haemodynamic Changes In Hypothermia Treatment
- Changes in CV β-adrenoceptor (reduced response)
- Increase in stroke volume
- Reduced intravascular volume during hypothermia is by 10– 35%
Lower heart rate is associated with good one-year outcome in postresuscitation patients (link)
Survivors Have Higher Mean Arterial Pressure (link)
Lowest value of DAP over the first 6 h after ICU admission for predicting unfavourable neurological outcome at 3 months (link)