Spontaneous intracerebral haemorrhage (ICH) accounts for approximately 10-15% of all strokes but stands for 50% of stroke-related morbidity and mortality. Approximately half of all patients with ICH have a decreased level of consciousness at hospital admission. Despite this, intensive care and neurosurgical interventions are uncommon. A study conducted in low- and middle-income countries has demonstrated a beneficial effect of a treatment package consisting of early intensive blood pressure lowering, as well as the treatment of pyrexia and elevated blood glucose levels. The I-CATCHER team is now planning to conduct a similar study in Sweden and Australia, as well as in other high-income countries. The study has a clear focus on implementation, aiming to improve treatment and prognosis for patients with ICH within a few years. The purpose of I-CATCHER is to investigate whether a structured treatment package (Care Bundle) improves 3-month prognosis in patients with spontaneous ICH compared to standard care.

Spontaneous intracerebral hemorrhage (ICH) accounts for 10 to 15% of all strokes in high-income countries (HIC), and nearly twice this number in low-income to upper-middle-income countries (LMIC) (29.5%). It is the most devastating type of stroke given the high one-month case fatality of approximately 30-40%, and only 12-39% suffer persistent disability.

Despite several advances in the management of acute ischemic stroke supported by numerous randomized controlled trials (RCT), progress in establishing novel interventions to improve outcomes for ICH has been slow. Still today, the diagnosis of ICH evokes pessimism among treating physicians, and patients may be withheld guideline adherent treatment for this reason. This nihilistic approach is presumably due to an over-estimation of poor outcome, often influenced by the neurologically devastating features commonly present at ICH admission. Additionally, the scarcity of RCTs providing strong evidence for treatment recommendations may contribute to a more reluctant approach in the acute setting of ICH, particularly when presenting with debilitating symptoms.

The third INTEnsive care bundle with BP reduction in acute cerebral hemorrhage trial (INTERACT3) was recently published in 2023. This trial employed a stepped wedge cluster RCT design to evaluate the implementation of a Care Bundle protocol. This comprehensive protocol included early intensive BP lowering (EIBPL), management of pyrexia and hyperglycemia, and the early reversal of OAC treatment. The design of this trial drew inspiration from a post-hoc analysis of the INTERACT2 study that showed that the scoring of abnormal baseline variables, interventions included in the future INTERACT3 Care Bundle, independently predicted a poor functional outcome following ICH. The implementation of the time sensitive bundle of care in INTERACT3 resulted in an improved functional outcome at 6 months following ICH. However, as the trial included patients predominantly from LMIC, further studies are warranted to determine if these results are applicable to HIC with a more applicable Care Bundle for these populations. An earlier intervention study from the United Kingdom, published in 2019, studied a similar 'quality improvement' acute Care Bundle. This Care Bundle aimed to improve the speed of treatment delivery, access to acute care, and decrease case fatality following ICH. Despite certain limitations, including a non-randomized design, this study demonstrated significantly lower mortality rates in patients receiving the Care Bundle versus the pre-implementation standard of care.

I-CATCHER is an international, multicenter, batched, parallel, cluster, randomized clinical trial (RCT) to assess a multifaceted package of protocols in a broad range of patients with acute ICH. In each batch, hospitals will be randomized into two groups according to the timing of the intervention (Care Bundle) over 3 phases (phase 1: usual care, phase 2: randomized evaluation - to intervention or usual care, phase 3: post-implementation follow-up - all hospitals implement the intervention). This design will capture consecutive patients with ICH and allow continued intervention in perpetuity as more hospitals join. Compared to a conventional stepped-wedge cluster RCT, the intervention effect in this design is less likely to be confounded by background temporal trends as only baseline and parallel comparison data (first 2 periods in bold black frame) are used to determine the effectiveness of the Care Bundle. All hospitals will be exposed to the Care Bundle which allows assessment of sustainability and integration of the intervention into routine practice. Each batch period is 18 months (6 months per phase); whole study will be rolled out in 2.5 years.

This design involves implementation of an intervention package applied to all patients with ICH as part of routine care. Patients are only excluded if they refuse to have details of their management included and/or participate in follow-up procedures.

Study site inclusion criteria: Organized systems of acute stroke care; no established comprehensive protocols for the management of ICH; suitable location, infrastructure and willingness to participate in clinical research; suitable numbers of ICH patients (at least 30 per year).

Patient inclusion criteria: Adults (≥18 years) with spontaneous ICH confirmed by imaging and admitted hospital within 24 hours of the onset of symptoms.

Inclusion Criteria:

• Adults (age ≥18 years)
• Non-contrast computerized tomography (NCCT) imaging-verified diagnosis of spontaneous intracerebral haemorrhage
• ≤24 hours from symptom onset or presumed symptom onset (last seen well)

Exclusion Criteria:

• Previous care limitation
• End-stage comorbidity with short life-expectancy (<6 m; e.g. terminal cancer)
• ICH caused by brain tumor or cerebral venous thrombosis
• Clinical signs of brain herniation at first presentation (unresponsive patient with bilaterally fixed, maximally dilated pupils)
• Pregnant women beyond 22 weeks gestation may only be included after thorough discussion with an obstetrician to determine risks vs benefit.

Treatment allocation is on a site-level and not on an individual level. The allocation is not blinded. Follow-up clinical outcome assessors, who have no prior association with the study and are unaware of the patients' allocation to either the intervention or control arm, will contact the participant by telephone at 6 months. At the initiation of contact, study subjects will be urged not to disclose their treatment allocation.