Letter to the authors of “Mind the drain: expanding TIMING-ICP discussion” and to the author of “Rethinking the clinical impact of timing in ICP monitoring initiation”

We read with great interest the response letter by Brasil et al. [1] to our recent study [2], as it raised several important points regarding the management of invasive intracranial pressure (ICP) monitoring.

We fully agree that the choice of monitoring technique should be guided by clinical needs, since conditions such as hydrocephalus and subarachnoid or intraventricular hemorrhage usually require cerebrospinal fluid drainage through an external ventricular drain (EVD). As the authors rightly noted, this procedure is technically more complex, falls within the neurosurgical domain, and therefore understandably requires longer procedural times. This trend was also observed in our analysis, although the difference did not reach statistical significance due to the limited sample size.

It is important to emphasize that the primary objective of our study was to directly compare intraparenchymal catheter placement performed by intensivists and neurosurgeons within the ICU. In this context, the differences in intervention times proved to be statistically significant. The timing of device placement in other settings (e.g., EVDs used exclusively for intracranial pressure monitoring or intraparenchymal catheters placed in the operating room) were included only as a secondary analysis. Since these procedures were rarely observed during the data collection period of the study, we subsequently continued the investigation by including only intraparenchymal catheters placed in the ICU, in order to obtain comparable groups based on the operator (intensivist vs. neurosurgeon) rather than on the type of procedure.

Complication rates were also compared between groups as a secondary outcome. Since the study was not powered to detect statistically significant differences in this regard, their occurrence was instead analyzed according to device type and found to be consistent with complication rates reported in the literature.

Looking ahead, future research should focus on whether earlier initiation of ICP monitoring translates into better patient outcomes. In fact, as mentioned by Citerio in another accompanying editorial regarding our work and published in this journal, we must bear in mind that although reducing time to insertion is certainly attractive, the real issue is whether earlier ICP values translate into meaningful therapeutic decisions and improved outcomes. A recent systematic review and meta-analysis by Abdollahifard et al. [3] addressed this question but found no significant differences in outcomes between early and late monitoring. These findings, however, require cautious interpretation given certain methodological limitations, some of which were already highlighted in Citerio’s commentary [4]. Most importantly, as emphasized in prior literature by Chesnut [5], ICP monitoring is not a treatment in itself: its true value lies in how clinicians interpret and act upon the information it provides, ideally within a multimodal monitoring and treatment framework.

Abbreviations

ICU

Intensive care unit

ICP

Intracranial pressure

EVD

External ventricular drains

Author contributions

L.M. and F.R. equally contributed to the drafting of this work.

Funding

The present study has not been funded.

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.