Cardiac arrest is a hot topic on St Emlyn’s. We are always looking for ways to improve our care for this critical group of patients. Recently, we have put out full articles on intra-arrest stellate ganglion blocks, arterial lines, and hysterotomy. I wanted to add a few quick hits that have popped up in Resuscitation over the last few months.
Thank you to the brilliant Edward Bezant – EM / ICU registrar and educator extraordinaire – for helping with these!
Should we be providing “goal-directed” chest compressions?
The first paper we chose is an animal study seeking evidence for personalised, goal-directed resuscitation in cardiac arrest.
The researchers induced VF in pigs (n=30) and then provided chest compressions “blind” or with a depth & frequency titrated to the ETCO2 (>1.3 kPa) +/- diastolic BP (>30 mmHg).
This approach makes physiological sense: we know that diastolic BP correlates with coronary perfusion pressure, and ETCO2 is a decent measure of cardiac output.
The goal-directed groups had superior rates of ROSC and neurological recovery, so there may be something to this. It is worth noting, however, that their precise chest compression technique relied on a custom-built device that is not widely available. Hopefully these results will spur on human trials!
How can we optimise our intra-arrest ventilation?
Our second paper is a prospective study from Spain examining ventilation strategies in a large sample (n=521) of patient intubated after out-of-hospital cardiac arrest.
Participants were randomised to one of three groups: (1) manual bag-valve-mask ventilation, (2) conventional mechanical ventilation, and (3) mechanical ventilation using a special ‘chest compression synchronized ventilation’ (CCSV) mode. In CSSV, the ventilator delivered small breaths (2.5ml/kg) between compressions.
Both forms of machine ventilation showed non-significant trends towards superiority across multiple patient-oriented outcomes (including neurologically-intact survival) with CCSV performing best overall.
This is a novel technique that is not widely available, although commercial systems offering it do exist. Larger studies are needed to establish whether the lack of statistical significance here was due to underpowering before the technique is ruled out for clinical use.
Can cerebral oximetry predict ROSC?
Finally, we have a feasibility study conducted in the US on the use of cerebral oximetry to predict the outcomes of in-hospital cardiac arrest.
A small number of patients (n=19) undergoing resuscitation were fitted with ‘cerebral oximeters.’ These devices are fitted to the forehead, and use near-infrared spectroscopy to provide a non-invasive estimate of regional cerebral oxygen saturation (rSO₂) in the underlying frontal cortex. Intuitively, this seems like relevant information in cardiac arrest. The purpose of life support is to maintain the flow of oxygenated blood to the brain. We can extrapolate this from other sources of information – e.g. arterial diastolic pressure – but a (semi) direct measurement makes sense.
The findings indicated that cerebral oximetry is a feasible adjunct to cardiac arrest care. The sensors took approximately fifteen seconds to attach, and did not interfere with chest compressions. Patients in whom return of spontaneous circulation (ROSC) was achieved had significantly higher mean rSO₂ (48% vs. 15%; p<0.0001) and, in multiple cases, a rise in rSO₂ signalled imminent ROSC.
What do we make of this study? At this stage, the numbers are too small – but I am really interested in rSO₂. It is not too hard to imagine future life-support algorithms including “rSO₂ surge” among the signs of circulatory reset. I would also be interested to see, in a follow-up study, what the mid-term outcomes are like for patients who achieve ROSC with poorer mean RSO2. Could this information help the ICU team with neuro-prognostication?
Ed – it also fits with the emerging concept of physiology based resuscitation and links to what St Emlyn’s have been talking about with regard to coronary perfusion pressure/DBP. If we want to know whether resuscitation is working we need to do more than just go round and round the algorithms, but rather need to measure the effectiveness. Obviously brain perfusion would be an interesting thing to know about.
The bottom line
Target-directed resuscitation is a really interesting area of research, and it may well be that in a few years’ time we will all be titrating our chest compressions to arterial DBP and cerebral SO₂. I find it more difficult to imagine ‘chest compression synchronised ventilation’ entering our practice in Virchester, because this would require a radical expansion of the equipment available to us during cardiac arrest.
Hope you enjoyed these quick hits! I did.
References
- Hernández-Tejedor A, Puebla VG, Torres EC, Hernández SI, Rodrigo CC, García MI, Leis CC. Comparison of ventilation modes in non-traumatic out-of-hospital cardiac arrest: SYMEVECA phase 2. Resuscitation. 2025 May 21:110655.
- Jiang T, Sun Y, Zhang H, Zhang Q, Tang S, Niu X, Guo Y, Li K, Chen Y, Xu F. Combined end-tidal CO2 and diastolic blood pressure–guided CPR improves survival from cardiac arrest in porcine model. Resuscitation. 2025 Aug 5:110745.
- Parnia S, Nasir A, Shah C, Patel R, Mani A, Richman P. A feasibility study evaluating the role of cerebral oximetry in predicting return of spontaneous circulation in cardiac arrest. Resuscitation. 2012 Aug 1;83(8):982-5.
