Treatment Decisions

The following areas will be important in the on going management of a patient post-ROSC:

Clinical neurological findings

Neurological prognostication should be performed using a multimodal strategy, to include clinical examination, electrophysiology, biomarkers and imaging.

Pathophysiological factors (e.g. hypoglycaemia) and interventions (hypothermia, sedation, atropine administration) will affect the neurological exam and must be considered.

Fig.1 From: European Resuscitation Council and European Society of Intensive Care Medicine guidelines 2021: post-resuscitation care

Prognostication strategy algorithm. EEG electroencephalography, NSE neuron specific enolase, SSEP somatosensory evoked potential, ROSC return of spontaneous circulation. 1. Major confounders may include sedation, neuromuscular blockade, hypothermia, severe hypotension, hypoglycaemia, sepsis, and metabolic and respiratory derangements. 2. Use an automated pupillometer, when available, to assess pupillary light reflex. 3. Suppressed background ± periodic discharges or burst-suppression, according to ACNS. 4. Increasing NSE values between 24 h-48 h or 24/48 h and 72 h further confirm a likely poor outcome. 5. Defined as a continuous and generalised myoclonus persisting for 30 min or more. *Caution in case of discordant signs indicating a potentially good outcome (see text for details)

Pupillary light reflex and corneal reflex, when both absent together bilaterally, at 72 hours or more post-ROSC, are very specific for poor outcome.

Comorbidities and age

Advanced age has been shown to be associated with worse survival rates in older patients. Neurological outcome also deteriorates with increasing age, but this deterioration isn’t always marked, and older patients have been shown to survive with favourable neurological outcomes.

The general consensus is that biological age should not form part of the decision to withdraw care post-ROSC, as age has no significant predictive value on mortality. [10]

Increasing comorbidity has also been shown to impact the 30-day survival rate after OHCA. This is particularly true of:

• Diabetes
• Renal disease
• Congestive heart failure
• Metastatic carcinoma

Older patients are more like to have comorbidities and so age may indirectly impact survival rates in this way instead. [11] However, there is no significant association between comorbidities and favourable neurological outcome. [12]

Type of arrest

The initial rhythm at first discovery of an out-of-hospital cardiac arrest also affects the prognosis. [13]

• • People experiencing ventricular tachycardia (VT) or ventricular fibrillation (VF) have the greatest chance of survival.
  • People who are found in pulseless electrical activity or asystole have the lowest chance of survival.

Downtime, delay to start of CPR and quality of CPR

Several studies have shown an association between poor outcome and increasing time interval between collapse and start of CPR and/or from the start of CPR to return of spontaneous circulation. [8]

This is also true of poor quality CPR. A low ETCO₂of <10mmHg during resuscitation (i.e. CO₂ as a marker of cardiac output – and therefore the quality of chest compressions – during CPR) is associated with poor outcome as is a low PaO₂ after ROSC. [14]

Learning bite

Increasing number of shocks or adrenaline doses correlate with poorer neurological outcome. [8]

Early blood gas interpretation

Following an OHCA, patients with a favourable outcome have been shown to have lower lactate and high pH values compared with those with an unfavourable outcome, according to retrospective analyses. [15]

In one study, the optimal cut-off point for lactate was found to be 80mg/dL and the pH found to be 7.05. pH is thought to be a better predictor for neurological outcome than lactate levels. [15]

CT/MRI Brain

This set of images shows a selection of CT scans obtained post ROSC. Click on the CTs to enlarge.

Fig 2: CT image of a normal brain	Fig 3: CT image of a posterior fossa bleed	Fig 4: CT image of extradural haematoma with overlying skull fracture

Conclusion

As a rule, post-ROSC comatose patients without significant pre-arrest co-morbidities should be taken to the ICU for supportive care, and their individual prognosis decided later by the intensive care team.

The best predictor of function we have is neurological outcome at 72 hours.

Delaying prognostication in individual patients until 72 hours post-ROSC may limit the problem that ‘perception of a likely adverse outcome … may well create a self-fulfilling prophecy’. [4]