Hemodynamic variability in patients undergoing decompressive craniotomy or craniectomy: A scoping review

Decompressive craniotomy or craniectomy (DC) is used to treat refractory intracranial hypertension in severe traumatic brain injury and malignant stroke. Heart rate variability (HRV) and blood pressure variability (BPV) may capture autonomic dysfunction and hemodynamic instability in this setting, but their role remains uncertain. This scoping review maps the evidence on HRV, BPV, and related hemodynamic variability in DC patients.

We conducted a scoping review in accordance with PRISMA-ScR guidelines. MEDLINE, Embase, Cochrane CENTRAL, CINAHL, and Web of Science were searched from inception to June 2025 for studies of any design reporting temporal variability in heart rate or blood pressure in patients undergoing DC. At least two reviewers independently screened records. Findings were summarized descriptively in tables and narrative, stratified by HRV and BPV metrics.

Twenty-three studies were included, comprising three randomized controlled trials, one randomized clinical study, and nineteen observational cohorts or case series (five of these were abstracts), with 1765 participants. Most studies enrolled adults with severe traumatic brain injury; a smaller number included malignant middle cerebral artery or other malignant anterior circulation infarction and mixed traumatic and vascular pathologies. Three studies reported formal HRV indices or baroreflex sensitivity, and two studies quantified BPV using statistics such as standard deviation or coefficient of variation; several others evaluated blood pressure instability. HRV was consistently depressed early after DC, and lower time and frequency domain indices were associated with higher mortality and unfavourable long-term neurological outcomes, while higher HRV correlated with better recovery. Higher early postoperative systolic BPV after hemicraniectomy independently predicted worse three-month functional outcomes. Randomized trials showed that ketamine-propofol anesthesia and stepwise decompression reduced intraoperative or early postoperative blood pressure swings without compromising surgical conditions.

Existing evidence, although limited and heterogeneous, suggests that reduced HRV and increased BPV are associated with worse outcomes in patients undergoing DC. Depressed HRV indices and large BP fluctuations appear to have prognostic value, whereas interventions that stabilize hemodynamics seem to improve early physiological outcomes. Future studies should standardize HRV/BPV measurements, validate these metrics prospectively, and test whether targeting hemodynamic variability can improve neurological outcomes after DC.