Chest compressions in traumatic cardiac arrest

Traumatic cardiac arrest (TCA) is an infrequent event in paediatrics and a cause of significant stress in the busy trauma resuscitation room. Outcomes are similar in both paediatric and adult arrests, with poor survival rates in both. There are now international guidelines on the management of traumatic cardiac arrest.

A traumatic cardiac arrest (TCA) is traumatic not just for patients but also for staff and all those involved. The guidelines were published in 2016. However, the role of chest compressions is still confusing for medical and nursing staff alike. Advanced Paediatric Life Support algorithms and supporting medical evidence have correctly engrained chest compressions into the medical management of life threats.

There is a paucity of studies examining trauma-induced hypovolaemic arrests to base the decision to change the “normal practice”. It is counter-intuitive for medical staff not to start compressions when an arrest is presented to you, and withholding them inevitably leads to the question, “Well, what can I do then?”.

Haemorrhage is one of the three common causes of early preventable death in trauma. This paper, from Sarah Watts et al., sought to determine whether compressions are beneficial and what fluid the patient should get (if any). Of course, there are ethical and practical issues with a prospective randomised control study involving children as the subjects. Instead, this animal study is a helpful surrogate for analysis of the question surrounding the role of chest compressions in haemorrhage-induced traumatic cardiac arrest.

Disclaimer: not suitable for vegetarians!

Watts S, Smith JE, Gwyther R and Kirkman E. Closed chest compressions reduce survival in an animal model of haemorrhage-induced traumatic cardiac arrest. Resuscitation. 2019; 140:37-42. Doi: 10.1016/j.resuscitation.2019.04.048

Population

39 pigs were enrolled and treated as per the UK Animals (Scientific Procedures) Act 1986 ethics standards. The baseline data of all animals involved were within normal ranges, and differences between them were not clinically significant. Each subject’s vital signs were invasively monitored throughout the study.

Intervention

There were 5 phases through which all participants/subjects went.

• Injury phase
• Shock phase
• TCA phase
• Resuscitation phase
• Post-resuscitation phase

Each subject was anaesthetised, and the same injury was reproduced in each. Subjects were allowed to exsanguinate in a controlled pattern. Once terminal hypovolaemia was declared, three rounds of resuscitation were commenced. After resuscitation, subjects were categorised according to MAP and Study End was defined as 15 minutes after the end of the third resuscitation cycle.

Patients were blindly randomised into 5 different groups:

1. Closed chest compressions(CCC)
2. Whole blood (WB)
3. 0.9% Saline (NaCl)
4. WB+ CCC
5. NaCl+ CCC

Outcome

The primary outcome was the achievement of ROSC at the study end.

Secondary outcomes were differences in survival, attainment, and maintenance of ROSC during the resuscitation and post-resuscitation phases.

Results

To summarise the numerous results:

1. All the subjects in the compressions-only group died.
2. All the subjects that received whole blood only survived.
3. Resuscitation with blood had improved outcomes over normal saline.
4. The addition of compressions had a detrimental effect on fluid resuscitation.
5. Subjects that received any combination of CCC showed a more significant metabolic acidosis, reflecting increased tissue ischaemia.
6. In the group that received both CCC and WB, 5 of 8 subjects achieved partial ROSC (MAP 20-50mmHg). Once partial ROSC was ascertained, CCC’s ceased and fluid resuscitation alone was continued. This led to the subjects improving to such a degree that there was no longer a difference between this group and that resuscitated by WB alone from the beginning.
7. All results can be attributed to the groups’ interventions as confounding variables were minimised and the initial injury reproduced in each case.

Discussion

While this is a small population study, it has become a sentinel paper. It demonstrates clear evidence that chest compressions in a TCA are detrimental and that our reflexive management of medical arrests is not transferable. We need to shift our focus to optimising fluid resuscitation. It shows a clinically relevant outcome that is internationally applicable. It is important to note that terminal hypovolaemia, not true cardiac arrest with no output, was being measured. However, terminal hypovolaemia is an imminent precursor of cardiac arrest.

Reflections from Nuala Quinn

I listened to Dr Sarah Watts present this paper, and her presentation reinforced my opinion that it is superb. It challenges the dogma and forces us to push beyond traditional management strategies in what is arguably the most stressful paediatric emergency: major trauma.

Closed chest compressions are a mainstay of medical management. They are firmly embedded in resuscitation culture and have become a mainstay of civilian culture. When healthcare practitioners hear the word “arrest,” they automatically move into the “chest compressions” mindset. However, medical cardiac arrest and traumatic cardiac arrest are two completely different entities with ensuing separate management. Anecdotally, it is difficult to separate the two, and advising a team that no one needs to do chest compressions in an arrest causes anxiety and confusion. This happened only recently in our department where advising one of our staff that we didn’t need to do chest compressions as a priority was met with “but it says in APLS so we need to do them”. 

So, how do we get around this? In my mind, we do this in two ways: 

Firstly, we use and promote the life-saving interventions for TCA and keep it a separate entity. When leading a TCA, as the pre-brief, I will usually start with, “This is a Traumatic Cardiac Arrest which will need the bundle of life-saving interventions before anything else”. I write the bundle of life-saving interventions on the adjacent whiteboard and assign specific people to them. I focus on the bundle rather than ABCDE. Focusing the team on the bundle, rather than the “arrest” per se, helps separate the medical arrest from the traumatic one. 

I follow the PERUKI guideline. The bundle needs to be prioritised over chest compressions and defibrillation. For revision, here is the bundle:

• External haemorrhage control
• Adequate oxygenation and ventilation
• Bilateral thoracostomies
• Rapid volume replacement with blood and blood products (crystalloid only if blood not available)
• Apply pelvic binder in blunt trauma

Secondly, we use the evidence, and this is where papers like Watts et al. come in. Evidence is fluid. It changes all the time. It takes years for resuscitation courses and bodies to update manuals, so it is our responsibility to use emerging evidence and use it sensibly and progressively. Watts’ paper helps me to educate and challenge dogma, particularly with compressions and saline resuscitation.

Again, anecdotally, the practice of giving saline as the initial resuscitation fluid in trauma exists.  We seem to be hesitant to give blood immediately, with the view that to try with saline first is better to not waste blood. The literature now abounds with papers describing the deleterious effects of saline in trauma, particularly with regard to its dilutional effects and role in worsening trauma coagulopathy. Again, this paper supports the choice of whole blood over saline and is in keeping with the life-saving bundle. 

This paper cements for me the reasons for the importance of the life-saving bundle before anything else and should empower us to make better decisions in trauma reception and resuscitation:

“Should we just give a saline bolus first?“

“Should we just get someone to do chest compressions as they have no pulse?”

The answer should always be no, and this paper provides evidence to support that. The TCA algorithms are almost exactly the same for adults, paediatrics, and institutions worldwide. This has really helped to standardize the management of TCA and have people trust the bundle rather than revert back to what feels safe for them (compressions and saline in most instances). 

As to our case above, I wasn’t team-leading, and with 10 minutes to the patient’s arrival, I didn’t want to push the issue, so the plan for compressions went ahead, and the role was assigned. However, at the end of the trauma resuscitation, I realised that the chest compressions hadn’t actually been performed. So in that clinician’s subconscious, there was an understanding and mutual trust in the process of changing and progressing how we better manage traumatic cardiac arrest. Watts and PERUKI are leading the way. It is up to us to follow them.

Selected references

Watts S, Smith JE, Gwyther R and Kirkman E. Closed chest compressions reduce survival in an animal model of haemorrhage-induced traumatic cardiac arrest. Resuscitation. 2019; 140:37-42. Doi: 10.1016/j.resuscitation.2019.04.048

Rickard AC, Vassallo J, Nutbeam T, Lyttle MD, Maconochie IK, Enki DG, et al. Paediatric traumatic cardiac arrest: a Delphi study to establish consensus on definition and management. Emerg Med J. 2018;35(7):434-9.

Vassallo J, Nutbeam T, Rickard AC, Lyttle MD, Scholefield B, Maconochie IK, et al. Paediatric traumatic cardiac arrest: the development of an algorithm to guide recognition, management and decisions to terminate resuscitation. Emerg Med J. 2018;35(11):669-74.

(ANZCOR) AaNZCoR. Australian Resuscitation Council Guidelines 2016 [Available from: https://resus.org.au/guidelines/.]