Post cardiac arrest syndrome: The case for an evidence-based bundle of care

Professor Anne-Maree KellyWestern Health

@kellyam_jec

This presentation may be reproduced in part or whole for education purposes on the condition that each reproduced slide contains the following:

‘Reproduced with permission of Professor Anne-Maree Kelly, Joseph Epstein Centre for Emergency Medicine Research @Western Health, Melbourne, Australia’

Permissions

Support for this meeting and advisory boards from Astra Zeneca

Travel support to speak at a conference (on blood gases) by Radiometer

Advisory board membership MSD

No relationships with manufacturers of hypothermia equipment

Co-author of NHF guidelines for the management of ACS and addenda & of some of the research mentioned in this talk

Editorial boards of:◦ Annals of Emergency Medicine◦ Emergency Medicine Australasia◦ Hong Kong Journal of Emergency Medicine

Conflicts of interest disclosure

My Colleagues Dr Stephen Bernard, Dr Karen Smith and colleagues for the ongoing, world leading body of work in this space

Acknowledgement

To review the pathophysiology of post-cardiac arrest syndrome

To summarize the evidence for a variety of interventions to improve outcome after out of hospital cardiac arrest

To propose the concept of a bundle of care approach to management of these patients

Objectives

72% in the home

Age 64 years (mean)

82% male

Ventricular fibrillation 37%

Pre-hospital -> advanced cardiac life support

If return of pulse -> transport to nearest ED

Background

Ventilation on 100% oxygen Sedation to maintain ETT 12 lead ECG Cardiology referral ICU referral Chest Xray Arterial line and ABG Bloods Bladder catheter Early (pessimistic) prognostication

Traditional ED treatment

ROSC rate = 24%Survival to discharge =7.6%

Sasson et al. Circ Cardiovasc Qual Outcomes 2010:3:63-812.

Cerebral and cardiac dysfunction due to prolonger whole body ischaemia

Elements◦ Anoxia brain injury◦ Myocardial dysfunction◦ Systemic ischaemia/ reperfusion response◦ Persistent precipitating pathology

Contribution of the elements varies between individuals

Pathophysiology of post cardiac arrest syndrome

Ventilation◦ 100% oxygen or normoxia?◦ What pCO2 target?

Blood pressure◦ What target and how?

Cath lab◦ Just STEMI?

Therapeutic hypothermia◦ If ‘Yes’, how?

Post cardiac arrest care: Evidence-based treatment

High oxygen concentration may increase free radical production

Some observational data (from ICU) that higher oxygenation is harmful

Each 100mmHg increase in pO2 (on ICU admission) associated with 24% increase in mortality

Currently the subject of RCT proposals

100% oxygen or normoxia?

Kilgannon et al. JAMA 2010;123:2717-2722

Avoidance of both hyperoxia and hypoxia

SpO2 target 94-96%

Avoid hypocarbia as it:◦ Causes cerebral vasoconstriction◦ Hyperventilation decreases cardiac output

Current recommendations

Increased blood pressure may improve cerebral perfusion, BUT Inotropes/ pressors may cause additional cardiac injury

Observational data only suggesting ~30% improvement in outcome with achievement of haemodynamic stability

Studies used different targets MAP 80-100mmHg vs 65-70mmHg

Optimal MAP target remains unclear

Achieving haemodynamic stability

Gaieski et al. Resuscitation; 2009;80:418-24.Sunde et al. Resuscitation 2007; 73:29-39.

Aim for mean arterial pressure of 65-100mmHg

Taken into consideration ‘usual’ BP and severity of myocardial dysfunction

Current recommendations

Judicious fluid loading

Inotropic drug therapy

Mechanical support devices e.g.◦ IABP◦ ECMO

Achieving haemodynamic stability

Anoxic brain injury responsible for ~2/3rds of deaths post cardiac arrest

Therapeutic hypothermia is a major recent advance in neuroprotection

How it works?◦ Multifactorial?◦ Decreases cerebral oxygen demand◦ ? Direct cellular effects◦ Reduction in reactive oxygen species generation

Neuroprotection

32°C-34°C for 12-24 hours 24 hours is current recommendation

In meta-analysis RR best cerebral performance categories 1.55 (95% CI 1.22-

1.96) RR survival to hospital discharge 1.35 (95% CI 1.10-1.65)

Therapeutic hypothermia

Arrich et al. Cochrane Database Syst Rev 2009; CD 004128

Strong RCT evidence of OHCA with VF as initial rhythm

Evidence less clear for PEA/ Asystole Lower overall survival Not all are cardiac in origin (? ~50%) Some trend towards benefit (one study)

Survival 19% vs 7% Good outcome13% vs. 0%

Variation by arrest type

Study Survival Good neurological outcome

HACA 59% vs 45% 55% vs 39%

Bernard 49% vs. 32% 49% vs. 26%

HACA. NEJM 2002;346:549-56Bernard et al. NEJM 2002; 346:557-63

Haschimi-Idrissi et al. Resuscitation 2001; 51:275-81.

Cooled IV fluids (40ml/kg) Surface cooling Intravascular cooling

Techniques

Persuasive animal data that the earlier the better

Two RCT have demonstrated that pre-hospital cooling using IV fluids is safe, feasible and effective

No clinical outcome benefit shown compared to in-hospital cooling (yet)◦ Main (probable explanation): small difference in times

When?

STEMI unconscious post cardiac arrest were excluded from PCI vs. thrombolysis trials

Initial ECG shows STEMI in 30-60% of patients with ROCS after OHCA

Good evidence that early angiography with view to PCI improves outcome for patients with STEMI (RCT and observational)

Cath lab for all…or none..or some?

Recent study showed significant coronary lesions present in up to 66% of patients with OHCA without ST elevation.

Registry data has reported primary PCI as an independent predictor of survival regardless of initial ECG (odds ratio, 2.06; 95% CI, 1.16 to 3.66).

What about NSTEMI?

Reynolds et al. J Intensive Care Med 2009; 24: 179-86.Dumas et al. Circ Cardiovasc Interv 2010; 3:200-7.

2902 post arrest patients in Victoria Transported to one of 70 hospitals 1816 (63%) of patients were treated at hospitals with 24 hour

cardiac interventional services After adjusting for differences in baseline characteristics,

treatment at hospitals with 24 hour cardiac interventional services was significantly associated with survival (odds ratio 1.40; 95% CI 1.12-1.74, p=0.003)

Australian data

Stub D et al. Heart. 201197:1489-94.

Bundles of care are a structured way of improving processes of care and patient outcomes

3-5 components performed collectively and reliably

ALL OR NONE

The power comes from the evidence-base and the consistency of implementation

Examples:◦ Central line bundle IHI◦ Goal-directed sepsis therapy

A bundle of care?

Initiation of therapeutic hypothermia in ED (32-34 C). Maintain for 24 hours with slow re-warming

Optimization of haemodynamic status (MAP 65-100mmHg) Transfer to cardiac catheter laboratory early Avoidance of hyperoxia (SpO2 94-96%)

A bundle of care post-cardiac arrest?

A number of ‘before-and-after’ studies support the concept.

For patients with OHCA (?VF initial rhythm)

SpO2 94-96%

Core temperature <35 C

MAP 65-100mmHg

Transfer to cath lab within 110 mins.

Some suggested ED targets

Systems of care for time critical illness improves outcomes

Emerging evidence of improved outcomes in OHCA in specialized centres (Japan and Sweden)◦ OR improved survival ~3.4

Is this workable in the Australian context?

Is there a case for cardiac arrest centres?

Questions