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Outcomes of patients with subarachnoid haemorrhage admitted to Australian and New Zealand intensive care units following a cardiac arrest
Jonathan Heaney, Eldho Paul, David Pilcher, Caleb Lin, Andrew Udy, Paul J Young
Crit Care Resusc 2020; 22 (3): 237-244
- Jonathan Heaney 1
- Eldho Paul 2
- David Pilcher 3, 4
- Caleb Lin 3
- Andrew Udy 2, 3
- Paul J Young 5, 6
This research was conducted during the tenure of a Clinical Practitioner Research Fellowship from the Health Research Council held by Paul Young. The Medical Research Institute of New Zealand is supported by independent research organisation funding from the Health Research Council of New Zealand.
OBJECTIVES: To describe the characteristics and outcomes of adults with a subarachnoid haemorrhage (SAH) admitted to Australian and New Zealand intensive care units (ICUs) with a cardiac arrest in the preceding 24 hours.
DESIGN: Retrospective cohort study.
SETTING: Study data from 144 Australian and New Zealand ICUs were obtained from the Australian and New Zealand Intensive Care Society Centre for Outcome and Resource Evaluation Adult Patient Database.
PARTICIPANTS: A total of 439 of 11 047 (3.9%) patients admitted to an ICU with a SAH had a documented cardiac arrest in the 24 hours preceding their ICU admission. The mean age of patients with SAH and a preceding cardiac arrest was 55.3 years (SD, 13.7) and 251 of 439 (57.2%) were female.
MAIN OUTCOME MEASURES: The primary outcome of interest was in-hospital mortality. Key secondary outcomes were ICU mortality, ICU and hospital lengths of stay, the proportion of patients discharged home.
RESULTS: SAH patients with a history of cardiac arrest preceding ICU admission had a higher mortality rate (81.5% v 23.3%; P < 0.0001) and a lower rate of discharge home (4.6% v 37.0%; P < 0.0001) compared with patients with SAH who did not have a cardiac arrest. Among patients with SAH who had a cardiac arrest and survived, 20 of 81 (24.7%) were discharged home. In SAH patients with cardiac arrest, having a GCS of 3, the Australian and New Zealand Risk of Death score, and being admitted to ICU for palliative care or organ donation were significant predictors of in-hospital death.
CONCLUSIONS: Almost one in five SAH patients who had a documented cardiac arrest in the 24 hours preceding ICU admission to an Australian and New Zealand ICU survived to hospital discharge, with around a quarter of these survivors discharged home. The neurological outcomes of these patients are uncertain, and understanding the burden of disability in survivors is an important area for further research.
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- Paul E, Bailey M, Pilcher D. Risk prediction of hospital mortality for adult patients admitted to Australian and New Zealand intensive care units: development and validation of the Australian and New Zealand Risk of Death model. J Crit Care 2013; 28: 935-41
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This article has a correction. Please see the erratum in the December 2020 edition for details
Between 3% and 11% of patients with SAH experience a cardiac arrest, 2
Accordingly, the primary aim of our study was to describe the characteristics and outcomes of adults with SAH who sustained a cardiac arrest before admission to an Australian and New Zealand ICU between 2008 and 2019 and to compare them with those of patients with a SAH who did not have a cardiac arrest before ICU admission. The secondary aim of this study was to describe temporal trends in in-hospital mortality in these patients over the same period. We hypothesised that, consistent with the experience elsewhere, 2, 3
Study designWe performed a retrospective cohort study using data from the Australian and New Zealand Intensive Care Society (ANZICS) Adult Patient Database (APD), a clinical quality registry run by the ANZICS Centre for Outcome and Resource Evaluation, which contains over 2.5 million ICU records from more than 190 ICUs since 1993, and presently receives over 180 000 ICU records every year from ICUs in both Australia and New Zealand. The Alfred Hospital Human Research Ethics Committee (Melbourne, VIC, Australia) approved the study (HRED ref: 409/17), with waiver of individual patient consent.
Study populationAll patients admitted to an Australian and New Zealand ICU from January 2008 to June 2019 were evaluated. The following diagnostic codes were used to identify patients with SAH:
- 402 (subarachnoid haemorrhage/arteriovenous malformation/intracranial aneurysm); or
- 1503 (subarachnoid haemorrhage/arteriovenous malformation/intracranial aneurysm, surgery for).
We divided the study cohort into those patients who experienced a cardiac arrest before ICU admission and those patients who did not. Cardiac arrest before ICU was defined as a cessation or sudden reduction in cardiac output leading to loss of effective circulation in the 24 hours before ICU admission.
The primary outcome of interest was in-hospital mortality. Secondary outcomes were ICU mortality, ICU and hospital length of stay, the proportion of patients discharged to a chronic care/rehabilitation facility, and the proportion of patients discharged home.
All calculated P values were two-tailed. A P < 0.05 was chosen to indicate statistical significance. No adjustment for multiplicity of comparisons was undertaken. All analyses were performed with SAS software version 9.4 (SAS Institute, Cary, NC, USA).
PatientsA total of 16 645 patients were admitted to an Australian and New Zealand ICU with a SAH between January 2008 and June 2019 of which 5217 met an exclusion criterion. Cardiac arrest status data were missing for 381 participants. Of the remaining patients, 439 of 11 047 (4.0%) had a documented cardiac arrest before ICU admission (Figure 1).
The age of patients with SAH was similar for those who did and did not have a cardiac arrest before ICU admission. Among those patients with cardiac arrest data available, patients with SAH who had a cardiac arrest before ICU admission were less likely to be female and had higher illness severity scores and a lower GCS (Table 1).
Patient outcomes and process of care measuresA total of 358 of 439 (81.5%) of patients with SAH who had a cardiac arrest before ICU admission died in hospital compared with 2471 of 10 608 (23.3%) who did not have a cardiac arrest (P < 0.0001). In the cardiac arrest group, 20 of 439 (4.6%) were discharged home compared with 3920 of 10 608 (37.0%) who did not have a cardiac arrest (P < 0.0001). Trends in in-hospital mortality of patients with SAH over time are shown in Figure 2. There was a significant decline in in-hospital mortality over time (25.1% in 2008 v 20.6% in 2019) for patients with SAH who had no cardiac arrest (P value for trend = 0.015); however, no such trend was seen (81.8% in 2008 v 87% in 2019) for patients with SAH who had a cardiac arrest before ICU admission (P value for trend = 0.65).
Data on the use of invasive ventilation in the first 24 hours in the ICU and the ICU and hospital lengths of stay are shown in Table 1, with patients with SAH who suffered a cardiac arrest being more likely to be invasively mechanically ventilated and having shorter ICU and hospital lengths of stay.
Patients with SAH who suffered a cardiac arrest were more likely to be admitted to the ICU for palliative care or to facilitate organ donation, with a total of 37 of 439 of such patients (8.4%) admitted to the ICU for palliative care and 68 of 349 (15.5%) admitted to the ICU to facilitate organ donation (Table 1).
Characteristics of survivors versus non-survivors among patients who had a cardiac arrest before ICU admissionThe characteristics of survivors versus non-survivors among patients with SAH admitted to the ICU following a recent cardiac arrest are shown in Table 2. The median ICU length of stay for patients who had a cardiac arrest and died was 25.4 hours (IQR, 14.2–47.1 hours) compared with 120 hours (IQR, 38.4–279 hours) for patients who survived (P < 0.0001). Among patients who had a cardiac arrest and survived, 20 of 81 (24.7%) were discharged home. Among patients with SAH who had a cardiac arrest, non-survivors had statistically significantly lower GCS and correspondingly lower motor scores compared with those who survived. In the multivariable regression, among patients with SAH who had a preceding history of cardiac arrest, a GCS of 3 and admission to the ICU for palliative care or organ donation were the strongest predictors of in-hospital death (Table 3).
Statement of principal findingsIn this multicentre retrospective cohort study evaluating the outcomes of patients with SAH admitted to Australian and New Zealand ICUs between 2008 and 2019, we found that almost one in five patients with SAH who had a documented cardiac arrest in the 24 hours preceding ICU admission survived to hospital discharge and around a quarter of these survivors were discharged home.
Relationship to previous studiesThe rates of survival that we observed among SAH patients with a preceding history of cardiac arrest in our series were higher than previously reported. 2, 3, 6
To our knowledge, this is the largest sample size of patients in whom outcomes following subarachnoid haemorrhage with cardiac arrest have been reported. Furthermore, our data was prospectively collected at multiple centres across Australia and New Zealand, and represented more than 90% of all relevant ICU admissions, providing a degree of generalisability in the study findings, at least for Australian and New Zealand clinicians.