Decompressive Craniectomy for Traumatic Brain Injury: Postoperative TCD Cerebral Hemodynamic Evaluation

Abstract

Background: There are no studies describing the cerebral hemodynamic patterns that can occur in traumatic brain injury (TBI) patients following decompressive craniectomy (DC). Such data have potentially clinical importance for guiding the treatment. The objective of this study was to investigate the postoperative cerebral hemodynamic patterns, using transcranial Doppler (TCD) ultrasonography, in patients who underwent DC. The relationship between the cerebral circulatory patterns and the patients' outcome was also analyzed. Methods: Nineteen TBI patients with uncontrolled brain swelling were prospectively studied. Cerebral blood circulation was evaluated by TCD ultrasonography. Patients and their cerebral hemispheres were categorized based on TCD-hemodynamic patterns. The data were correlated with neurological status, midline shift on CT scan, and Glasgow outcome scale scores at 6 months after injury. Results: Different cerebral hemodynamic patterns were observed. One patient (5.3%) presented with cerebral oligoemia, 4 patients (21%) with cerebral hyperemia, and 3 patients (15.8%) with cerebral vasospasm. One patient (5.3%) had hyperemia in one cerebral hemisphere and vasospasm in the other hemisphere. Ten patients (52.6%) had nonspecific circulatory pattern. Abnormal TCD-circulatory patterns were found in 9 patients (47.4%). There was no association between TCD-cerebral hemodynamic findings and outcome. Conclusion: There is a wide heterogeneity of postoperative cerebral hemodynamic findings among TBI patients who underwent DC, including hemodynamic heterogeneity between their cerebral hemispheres. DC was proved to be effective for the treatment of cerebral oligoemia. Our data support the concept of heterogeneous nature of the pathophysiology of the TBI and suggest that DC as the sole treatment modality is insufficient.

Intracranial Compliance Assessed by Intracranial Pressure Pulse Waveform

“…Patients submitted to DC have a more severe neurological condition, and that is the reason why the ICP was higher and the P2/P1 ratio remained higher after DC in comparison to other groups. Interestingly, despite the higher ICP values, our study demonstrated greater ICC in this group as observed with the P2/P1 ratio after an induced rise in ICP [23,24]. This phenomenon has never been demonstrated before and should be further explored as an indicator of successful DC.…”

Decompressive Craniectomy in the ICU: Usefulness of Transcranial Doppler (TCD/TCCS) in the Monitoring of Hemodynamic Changes

“…• Sites of dural insertion. Although literature [40] has defined "hyperemia" with MCA MFV >100 cm/s, there is an increase in MCA MFV >30% in comparison with pre-DC values. Turbulent flow, vascular congestion, increasing spectral Doppler waveform amplitude and a marked decrease in PI are also shown, which suggests a possible "exacerbated" reperfusion phenomena of the vascular territories secondary to intracranial pressure reduction after DC.…”

“…Understanding the different cerebral hemodynamic patterns (pre-and post-DC), help the implementation of timely therapeutic decisions individualized to optimize CPP for each patient. Therefore, keep in mind that generalized treatment goals [17] can lead to hypo-or hyperperfusion phenomena, being deleterious for the patient [11,12,39,40] (Figs. 55.4a-c and 55.5).…”

Transcranial Doppler (TCD/TCCS) Approaches: Acoustic Windows

“…The most common difference after decompressive craniectomy is an asymmetrical increase in cerebral blood flow velocities with a higher increase in the decompressed side than the opposite side. A decrease in the pulsatility index has also been reported [19][20][21]. Monitoring the decompressed patient with transcranial Doppler ultrasound is remarkably important as different hemodynamic patterns have been described after the procedure.…”