Cardiopulmonary resuscitation after experimental hypovolaemic cardiac arrest
Principal investigator: Lars Wiklund
Background: Trauma is the main cause of death in citizens of the whole west hemisphere between the ages 1 and 38 years. It is estimated that by year 2020 deaths from injury are predicted to increase up to 8.4 million world-wide and uncontrolled haemorrhage will be responsible for 30% of these deaths. Despite improvements in resuscitation techniques and surgical management of trauma victims, survival rates remain extremely low in trauma patients who exsanguinate to cardiac arrest and have not improved significantly during the last decades. Thus, resuscitation from hemorrhagic shock and subsequent cardiac arrest is a major clinical challenge in the care of patients after motor vehicle accidents, gunshot or stab wounds, and combat. Nevertheless, even after successful restoration of spontaneous circulation (ROSC) following cardiac arrest, the morbidity and mortality depend mainly on the recovery of neurological function. However, the immediate challenge in emergency and operating rooms also when handling these in many instances young patients is to achieve restoration of spontaneous circulation that is the ultimate aim and demand in order to achieve preservation of neurological function.
This is because the general experience in such situations is that even after very short circulatory arrests it is often almost impossible to achieve ROSC, in contrast to normovolaemic cardiac arrests of considerably longer duration. This has been confirmed also experimentally, and in addition, we have also observed that intrathoracic cardiac massage is a prerequisite for success. Different blood volume substitutes have been tried and hypertonic saline with dextran has so far been superior to autologous blood and Ringer’s acetate. Block of nitric oxide action has not improved the results, in contrast to normovolaemic cardiac arrests of longer duration. Hypovolaemic cardiac arrests of somewhat longer duration can be successfully treated when and if an antiarrhythmic agent (amiodar-one) is administered during open thoracic CPR. Lately gender differences in circulatory and cerebral adaptation to ischaemia have been investigated in immature piglets where there is no differences in sexual hormone concentration in plasma. We have found that female piglets have a better capacity to adapt both circulatory and cerebral parameters to serious ischaemia. Methylene blue, probably by its inhibitory action on the nitric oxide-guanylyl cyclase pathway, improves circulatory and cerebral adaptation to ischaemia only in male piglets. However, not quite up to the still better level in female piglets. Our findings do indicate that female animals already before having sexual hormones have a better innate protection against ischaemia than their male counterparts.
Members of the group in 2013
Lars Wiklund, Professor
Ingemar Thiblin, Professor in Forensic Medicine
Sten Rubertsson, Professor
Hari Shanker Sharma, PhD, Associate Professor
Ala Nozari, MD, PhD Harvard Medical School
Egidijus Semenas, MD, PhD student