Real-world study suggests monitoring may lead to better long-term outcomes

Intracranial pressure (ICP) monitoring varied widely among institutions and appeared to be associated with a more intensive therapeutic approach and better long-term clinical results in severe cases of acute brain injury, the SYNAPSE-ICU study found.

In a global study of adult patients in intensive care units (ICUs) with acute brain injury, the researchers found considerable variability in the use of ICP monitoring (median OR 4.5 between any two randomly chosen centers, 95% CI 3.8-4.9), reported Giuseppe Citerio, MD, of the University of Milano-Bicocca in Italy, and co-authors in Lancet Neurology.

ICP monitoring was associated with significantly lower 6-month mortality in patients with at least one unreactive pupil (HR 0.35, 95% CI 0.26-0.47; P<0.0001) and better neurological outcome at 6 months (OR 0.38, 95% CI 0.26-0.56; P=0.0025).

Median therapy intensity level (TIL), a scale ranging from lower (0) to higher (38) care intensity, was greater for people who received ICP monitoring than those who did not (9 versus 5, respectively). A reduction of 1 point in TIL was associated with a 6-month mortality reduction (HR 0.94, 95% CI 0.91-0.98; P=0.0011).

“The main finding of our study is that there is considerable variability in the indications for and the use of ICP monitoring in hospitals and ICUs,” Citerio and colleagues wrote.

“Clinical status and neuroimaging results are the main factors used by clinicians in decisions to insert an ICP monitoring device,” they continued. “Our results suggest that ICP monitoring could lead to a more aggressive therapeutic approach aimed at controlling ICP and might be associated with reduced mortality in the most severely ill patients.”

The most recent Brain Trauma Foundation guidelines downgraded the strength of recommendation for ICP monitoring in TBI, Citerio and co-authors noted. “Indications for monitoring, therefore, remain unclear and, in clinical practice, the decision to insert an ICP monitoring device seems to be based mainly on experience and local policies.”

Elevated intracranial pressure is a major complication of acute brain injury. In large cohort studies, ICP has been independently associated with increased risk of death and poor outcome.

SYNAPSE-ICU was a prospective, real-world study that included 2,395 adults with traumatic brain injury (54%), intracranial hemorrhage (25%), or subarachnoid hemorrhage (22%) from 42 countries between March 2018 and April 2019. The cohort was 65% male and median age was 55.

All patients had a Glasgow Coma Scale (GCS) eye response score of 1 (not opening eyes) and a GCS motor response of 5 or less (not following commands) on admission to the ICU, or clinical deterioration within 48 hours of ICU admission.

Patients who had ICP monitoring—56% of the overall cohort—were younger and had fewer comorbidities than those who were not monitored.

In addition to 6-month mortality, primary outcomes included 6-month Glasgow Outcome Scale Extended score (GOSE; higher scores indicate a better outcome), with a poor outcome defined as a GOSE score less than 5. Worse 6-month outcomes occurred in 60% of people in the ICP monitoring group and 65% of those not monitored (P=0.039).

“Our results highlight the importance not only of ICP monitoring but also of aggressive ICP monitoring-driven treatment, which can effectively improve mortality in patients with more severe clinical signs of intracranial hypertension but potentially lead to higher rates of unfavorable neurological outcomes,” the researchers wrote.

The most common reasons for not using ICP monitoring were too severe a clinical status (25%) or imaging results either too severe or not severe enough to require invasive monitoring (25%). In 18%, ICP was not monitored because of local policy. Researchers also found more use of ICP monitoring in high-income countries (61% of 1,954 participants) than low-income and middle-income countries (33% of 441 participants).

“For the first time, a large, prospective, international collection of data has been gathered, representing real-world clinical practice, to assess the use of ICP monitoring in individuals with traumatic brain injury, intracerebral hemorrhage, and subarachnoid hemorrhage, paving the way for an update in the recognition of ICP monitoring in this field,” noted Jiyao Jiang MD, of the Shanghai Jiao Tong University in China and co-authors, in an accompanying editorial.

Together with earlier findings for ICP in traumatic brain injury, the study shows that “global collaboration in the field of acute brain injury is feasible,” the editorialists wrote.

“Further research should focus on the comparative effectiveness of treatment across countries and continents,” they added. “Investigation into the large variability in high-quality randomized controlled trials will eventually lead to a breakthrough in the understanding of ICP monitoring and guide policy makers and clinicians to focus on advanced ICP management for acute brain injury.”

While the most recent Brain Trauma Foundation guidelines suggest ICP monitoring may be used to help manage severe traumatic brain injury, “the indications, type of monitoring device to be used, and optimal duration of the monitoring are not clearly defined,” Citerio and colleagues pointed out.

Moreover, “no strong evidence exists to support the superiority of ICP monitoring-driven therapy versus other therapeutic approaches,” and extant literature mostly concerns traumatic brain injury but does not include causes of elevated ICP like hemorrhagic stroke, they added.

Limitations of the study include its observational design, from which causal inferences cannot be made. In addition, intracranial pressure management was not reported in detail for patients who did not have ICP monitoring.

  1. Intracranial pressure (ICP) monitoring varied widely among institutions and appeared to be associated with a more intensive therapeutic approach and better long-term clinical results in severe cases of acute brain injury, the SYNAPSE-ICU study found.

  2. Clinical status and neuroimaging results were the main factors clinicians used to help decide whether to insert an ICP monitoring device.

Paul Smyth, MD, Contributing Writer, BreakingMED™

This study was funded by the University of Milano-Bicocca and the European Society of Intensive Care Medicine.

Citerio reported grants and personal fees as a member of a speakers’ bureau and advisory board from Integra and Neuroptics, all outside the submitted work.

Jiang declared no competing interests.

Cat ID: 130

Topic ID: 82,130,570,730,130,38,474,255,925