Therapeutic hypothermia after in-hospital cardiac arrest: a critique

Enhancing Liver Transplant Outcomes through Liver Precooling to Mitigate Inflammatory Response and Protect Mitochondrial Function

Transplanted organs experience several episodes of ischemia and ischemia-reperfusion. The graft injury resulting from ischemia-reperfusion (IRI) remains a significant obstacle to the successful survival of transplanted grafts. Temperature significantly influences cellular metabolic rates because biochemical reactions are highly sensitive to temperature changes. Consequently, lowering the temperature could reduce the degradative reactions triggered by ischemia. In mitigating IRI in liver grafts, the potential protective effect of localized hypothermia on the liver prior to blood flow obstruction has yet to be explored. In this study, we applied local hypothermia to mouse donor livers for a specific duration before stopping blood flow to liver lobes, a procedure called "liver precooling". Mouse donor liver temperature in control groups was controlled at 37 °C. Subsequently, the liver donors were preserved in cold University of Wisconsin solution for various durations followed by orthotopic liver transplantation. Liver graft injury, function and inflammation were assessed at 1 and 2 days post-transplantation. Liver precooling exhibited a significant improvement in graft function, revealing more than a 47% decrease in plasma aspartate transaminase (AST) and alanine aminotransferase (ALT) levels, coupled with a remarkable reduction of approximately 50% in liver graft histological damage compared to the control group. The protective effects of liver precooling were associated with the preservation of mitochondrial function, a substantial reduction in hepatocyte cell death, and a significantly attenuated inflammatory response. Taken together, reducing the cellular metabolism and enzymatic activity to a minimum level before ischemia protects against IRI during transplantation.

Targeted temperature management in neurological intensive care unit

Targeted temperature management (TTM) shows the most promising neuroprotective therapy against hypoxic/ischemic encephalopathy (HIE). In addition, TTM is also useful for treatment of elevated intracranial pressure (ICP). HIE and elevated ICP are common catastrophic conditions in patients admitted in Neurologic intensive care unit (ICU). The most common cause of HIE is cardiac arrest. Randomized control trials demonstrate clinical benefits of TTM in patients with post-cardiac arrest. Although clinical benefit of ICP control by TTM in some specific critical condition, for an example in traumatic brain injury, is still controversial, efficacy of ICP control by TTM is confirmed by both in vivo and in vitro studies. Several methods of TTM have been reported in the literature. TTM can apply to various clinical conditions associated with hypoxic/ischemic brain injury and elevated ICP in Neurologic ICU.

The Outcomes of Targeted Temperature Management After Cardiac Arrest at Emergency Department: A Real-World Experience in a Developing Country

Targeted temperature management (TTM) is indicated for comatose survivors of cardiac arrest to improve outcomes. However, the benefit of TTM was verified by rigid controlled clinical trials. This study aimed at evaluating its effects in real-world practices. A prospective observational study was done at the emergency department of tertiary care, Thammasat Hospital, from March 2012 until October 2015. We included all who did not obey verbal commands after being resuscitated from cardiac arrest regardless of initial cardiac rhythm. We excluded patients with traumatic arrest, uncontrolled bleeding, younger than 15 years old, and of poor neurological status (Glasgow coma scale below 14) before cardiac arrest. Primary and secondary outcomes were survival to hospital discharge and favorable neurological outcome (Cerebral Performance Categories 1 or 2 within 30 days). We used the logistic regression model to estimate the propensity score (PS) that will be used as a weight in the analysis. To analyze outcomes, the PS was introduced as a factor in the final logistic regression model in conjunction with other factors. A total of 192 cases, 61 and 131 patients, were enrolled in TTM and non-TTM groups, respectively. Characteristics believed to be related to initiation of TTM: gender, age, cardiac etiology, out-of-hospital cardiac arrest, witness arrest, collapse time, initial rhythm, received defibrillation, and advanced airway insertion, were included in multivariable analysis and estimated PS. After adjusted regression analysis with PS, the TTM group had a better result in survival to hospital discharge (34.43% vs. 12.21%; adjusted incidence risk ratio (IRR), 2.95; 95% confidence interval (CI), 1.49-5.84; p = 0.002). For neurological outcome, the TTM group had a higher number of favorable neurological outcomes (24.59% vs. 6.87%; IRR, 3.96; 95% CI, 1.67-9.36; p = 0.002). In real-world practices without a strictly controlled environment, TTM can improve survival and favorable neurological outcome in postcardiac arrest patients regardless of initial rhythm.

Effect of therapeutic hypothermia on the outcomes after out-of-hospital cardiac arrest according to initial ECG rhythm and witnessed status: A nationwide observational interaction analysis

BACKGROUND

The use of mild therapeutic hypothermia (TH) in out-of-hospital cardiac arrest (OHCA) with shockable rhythms is recommended and widely used. However, it is unclear whether TH is associated with better outcomes in non-shockable rhythms.

METHODS

This is a retrospective observational study using a national OHCA cohort database composed of emergency medical services (EMS) and hospital data. We included adult EMS-treated OHCA patients of presumed cardiac etiology who were admitted to the hospital during Jan. 2008 to Dec. 2013. Patients without hospital outcome data were excluded. The primary outcome was good neurological outcome at discharge; secondary outcome was survival to discharge. The primary exposure was TH. We compared outcomes between TH and non-TH groups using multivariable logistic regression, adjusting for individual and Utstein factors. Interactions of initial ECG rhythm and witnessed status on the effect of TH on outcomes were tested.

RESULTS

There were 11,256 patients in the final analysis. TH was performed in 1703 patients (15.1%). Neurological outcome was better in TH (23.5%) than non-TH (15.0%) (Adjusted OR=1.25, 95% CI 1.05-1.48). The effect of TH on the odds for good neurological outcome was highest in the witnessed PEA group (Adjusted OR=3.91, 95% CI 1.87-8.14). Survival to discharge was significantly higher in the TH group (55.1%) than non-TH (35.9%) (Adjusted OR=1.76, 95% CI 1.56-2.00).

CONCLUSIONS

In a nationwide observational study, TH is associated with better neurological outcome and higher survival to discharge. The effect of TH is greatest in witnessed OHCA patients with PEA as the initial ECG rhythm.