Researchers may have developed a way to potentially assist prognostication in the first 24 hours after out-of-hospital cardiac arrest (OHCA) when patients are still in a coma. Their findings are revealed today at Acute Cardiovascular Care 2014 by Dr Jakob Hartvig Thomsen from Copenhagen, Denmark.
Acute Cardiovascular Care is the annual meeting of the Acute Cardiovascular Care Association (ACCA) of the European Society of Cardiology (ESC) and takes place 18-20 October in Geneva, Switzerland.
Dr Thomsen said: "When we talk to relatives and friends immediately after a cardiac arrest we often tell them that we're not able to say much about the prognosis for their Dad, Mom, friend, etc, for the next 3 to 4 days. This is incredibly distressing and loved ones are desperate for more information."
He added: "Therapeutic hypothermia is used in comatose survivors of OHCA to protect them from brain damage. Current recommendations say that prognostication should not be made until 72 hours after hypothermia when patients have returned to normothermia and the sedation has worn off.1 The prognostic tools presently available are not reliable until after this 72 hour period."
Dr Thomsen continued: "During hypothermia some patients lower their heart rate, which is called bradycardia. We hypothesised that this is a normal physiological reaction and that these patients may have less severe brain injury after their arrest and therefore lower mortality."
The study was conducted in the intensive care unit at Copenhagen University Hospital during 2004-2010 and was supported by the EU Interreg IV A programme. It included 234 comatose survivors of OHCA who underwent the hospital's standard 24 hour therapeutic hypothermia protocol. Heart rhythm was measured hourly and sinus bradycardia (defined as less than 50 heart beats per minute) was used to stratify the patients. The primary endpoint was 180 day mortality.
The investigators found that patients who experienced sinus bradycardia during therapeutic hypothermia had a 17% 180 day mortality rate compared to 38% in those with no sinus bradycardia (p<0.001) (figure 1), with a hazard ratio (HR) of 0.38. Sinus bradycardia during therapeutic hypothermia remained an independent predictor of lower 180 day mortality with a HR of 0.51 after adjusting for known confounding factors including sex, age, comorbidity, witnessed arrest and bystander CPR.
Dr Thomsen said: "Patients with sinus bradycardia during therapeutic hypothermia had a 50-60% lower mortality rate at 180 days than those with no sinus bradycardia. We also found that sinus bradycardia was directly associated with a better neurological status 180 days after the arrest."
Few patients are in sinus bradycardia when they arrive at the intensive care unit (a period called the induction phase). However the proportion rises during hypothermia to almost 50%, and then declines during the rewarming phase.
Dr Thomsen said: "We speculated that this proportion of patients who develop sinus bradycardia during hypothermia would have better brain function and a lower mortality rate, and that was what we found. "
He added: "Now when we observe that a patient experiences sinus bradycardia below 50 beats per minute within the first 24 hours we can tell families that their relative may have a chance of recovery."
Dr Thomsen continued: "There is a lot of discussion about defining criteria to identify patients we should stop treating when a vegetative state is inevitable. We shouldn't give up on patients who still have a chance so this is an area in which we need to be very certain. Our findings provide an early marker of patients who may do well. Hopefully in the future, together with other tools, we will be able to differentiate between those with a very good or very poor prognosis so we can prioritise intensive care resources."
He concluded: "We are currently validating our findings by conducting the same analysis in the 950 patients included in the Targeted Temperature Management trial which was conducted in 36 intensive care units."
Jacqueline Partarrieu | Eurek Alert!
Speed data for the brain’s navigation system
06.12.2016 | Deutsches Zentrum für Neurodegenerative Erkrankungen e.V. (DZNE)
Study suggests possible new target for treating and preventing Alzheimer's
02.12.2016 | Oregon Health & Science University
In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.
Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...
Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...
A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.
Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.
“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...
The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.
The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
06.12.2016 | Materials Sciences
06.12.2016 | Medical Engineering
06.12.2016 | Power and Electrical Engineering