Feasibility and Safety of Integrating Extended TCD Assessments in a Full Multimodal Neuromonitoring Protocol After Traumatic Brain Injury.

OBJECTIVE: Targeting single monitoring modalities such as intracranial pressure (ICP) or cerebral perfusion pressure alone has shown to be insufficient in improving outcome after traumatic brain injury (TBI). Multimodality monitoring (MMM) allows for a more complete description of brain function and for individualized management. Transcranial Doppler (TCD) represents the gold standard for continuous cerebral blood flow velocity assessment, but requires high levels skill and time. In TBI, the practical aspects of conducting extended TCD monitoring sessions have yet to be evaluated. METHODS: Patients with acute moderate-to-severe TBI admitted to the neurocritical care unit between March 2022 and December 2023 receiving invasive ICP measurements were evaluated for inclusion. Exclusion criteria included trauma incompatible with TCD monitoring and if MMM was unwarranted. Daily MMM sessions (in addition to regular monitoring) were performed using TCD (Delica EMS 9D System or the DWL Doppler Box) for ≤5 d. Quantitative and qualitative feasibility, safety, and quality metrics were assessed. RESULTS: Of 74 patients, 36 (75% male; mean age, 44 ± 17 y) were included. Common reasons for exclusion were skull fractures (n = 12) and decompressive craniectomy (n = 9). We acquired 88 recordings (mean, 275 ± 88 min). Overall monitoring times increased, and set-up times decreased. Physiologic variables (including ICP/brain temperature) did not change with TCD application. A single adverse event (dislodging of a microdialysis catheter) occurred. CONCLUSION: Implementing extended TCD monitoring in MMM protocols is feasible and safe. Considering these results, inclusion of long-term TCD as part of the MMM is strongly encouraged to allow for in-depth description and direct evaluation of hemodynamic changes after TBI.

Reliability and variability of pressure reactivity index (prx) during oscillatory pattern in arterial blood pressure and intracranial pressure in traumatic brain injured patients.

Introduction: Pressure reactivity index (PRx) is used for continuous monitoring of cerebrovascular reactivity in traumatic brain injury (TBI). However, PRx has a noisy character. Oscillations in arterial blood pressure (ABP) introduced by cyclic positive end-expiratory pressure adjustment, can make PRx more reliable. However, if oscillations are introduced by the cycling process of an anti-decubitus-mattress the effect on PRx is confounding, as they affect directly also intracranial pressure (ICP). In our routine monitoring in TBI patients we noticed periods of highly regular, slow, spontaneous oscillations in ABP and ICP signals. Research question: We set out to explore the nature of these oscillations and establish if PRx remains reliable during the oscillations. Materials and methods: 10 TBI patients' recordings with oscillations in ICP and ABP were analysed. We computed PRx, PRx variability (hourly-average of standard-deviation, SD), phase-shift and coherence between ABP and ICP in the slow frequency range. Metrics were compared between oscillation and peri-oscillation periods. Results: During oscillations (frequency 0.006 ± 0.002Hz), a significantly lower variability of PRx (SD 0.185vs0.242) and higher coherence ABP-ICP (0.618 ± 0.09 vs 0.534 ± 0.09) were observed. No external oscillations sources could be identified. 34 out of 48 events showed signs of 'active' transmission associated with negative PRx, indicating a potential positive impact on PRx reliability. Discussion and conclusions: Spontaneous oscillations observed in ABP and ICP signals were found to enhance rather than confound PRx reliability. Further research is warranted to elucidate the nature of these oscillations and develop strategies to leverage them for enhancing PRx reliability in TBI monitoring.

Exploration of uncertainty of PRx time trends.

Introduction: PRx can be used as surrogate measure of Cerebral Autoregulation (CA) in traumatic brain injury (TBI) patients. PRx can provide means for individualising cerebral perfusion pressure (CPP) targets, such as CPPopt. However, a recent Delphi consensus of clinicians concluded that consensus could not be reached on the accuracy, reliability, and validation of any current CA assessment method. Research question: We aimed to quantify the short-term uncertainty of PRx time-trends and to relate this to other physiological measurements. Material and methods: Intracranial pressure (ICP), arterial blood pressure (ABP), end-tidal CO2 (EtCO2) high-resolution recordings of 911 TBI patients were processed with ICM + software. Hourly values of metrics that describe the variability within modalities derived from ABP, ICP and EtCO2, were calculated for the first 24h of neuromonitoring. Generalized additive models were used to describe the time trend of the variability in PRx. Linear correlations were studied for describing the relationship between PRx variability and the other physiological modalities. Results: The time profile of variability of PRx decreases over the first 12h and was higher for average PRx ∼0. Increased variability of PRx was not linearly linked with average ABP, ICP, or CPP. For coherence between slow waves of ABP and ICP >0.7, the variability in PRx decreased (R = -0.47, p < 0.001). Discussion and conclusion: PRx is a highly variable parameter. PRx short-term dispersion was not related to average ICP, ABP or CPP. The determinants of uncertainty of PRx should be investigated to improve reliability of individualised CA assessment in TBI patients.

Improving Patient Outcomes in Abdominal Surgery.

Post-operative acute kidney injury (PO-AKI) is a frequent complication described in 15% of non-cardiac surgeries, 30% of cardiac surgeries, and 52% of patients requiring intensive post-operative care [...].

Red solid line: Patterns of terminal loss of cerebrovascular reactivity at the bedside.

Introduction: Continuous monitoring of the pressure reactivity index (PRx) provides an estimation of dynamic cerebral autoregulation (CA) at the bedside in traumatic brain injury (TBI) patients. Visualising the time-trend of PRx with a risk bar chart in ICM + software at the bedside allows for better real-time interpretability of the autoregulation status. When PRx>0.3 is sustained for long periods, typically of at least half an hour, the bar shows a pattern called "red solid line" (RSL). RSL was previously described to precede refractory intracranial hypertension and brain death. Research question: We aimed to describe pathophysiological changes in measured signals/parameters during RSL. Material and methods: Observation of time-trends of PRx, intracranial pressure, cerebral perfusion pressure, brain oxygenation and compensatory reserve of TBI patients with RSL. Results: Three pathophysiological patterns were identified: RSL precedes intracranial hypertension, RSL is preceded by intracranial hypertension, or RSL is preceded by brain hypoperfusion. In all cases, RSL was followed by death and the RSL onset was between 1 h and 1 day before the terminal event. Discussion and conclusion: RSL precedes death in intensive care and could represent a marker for terminal clinical deterioration in TBI patients. These findings warrant further investigations in larger cohorts to characterise pathophysiological mechanisms underlying the RSL pattern and whether RSL has a significant relationship with outcome after TBI.

Analgesic Strategies for Urologic Videolaparoscopic or Robotic Surgery in the Context of an Enhanced Recovery after Surgery Protocol: A Prospective Study Comparing Erector Spinae Plane Block versus Transversus Abdominis Plane Block.

Regional anesthesia in postoperative pain management has developed in recent years, especially with the advent of fascial plane blocks. This study aims to compare the ultrasound-guided bilateral erector spinae plane block (ESPB) versus the ultrasound-guided bilateral transversus abdominis plane block (TAPB) on postoperative analgesia after laparoscopic or robotic urologic surgery. This was a prospective observational study; 97 patients (ESPB-group) received bilateral ultrasound-guided ESPB with 20 mL of ropivacaine 0.375% plus 0.5 mcg/kg of dexmedetomidine in each side at the level of T7-T9 and 93 patients (TAPB-group) received bilateral ultrasound-guided TAPB with 20 mL ropivacaine 0.375% or 0.25%. The primary outcome was the postoperative numeric rating scale (NRS) pain score, which was significantly lower in the ESPB group on postoperative days 0, 1, 2, and 3 (p < 0.001) and, consequently, the number of patients requiring postoperative supplemental analgesic rescue therapies was significantly lower (p < 0.001). Concerning the secondary outcomes, consumption of ropivacaine was significantly lower in the group (p < 0.001) and the total amount of analgesic rescue doses was significantly lower in the ESPB-group than the TAPB-group in postoperative days from 2 to 4 (1 vs. 3, p > 0.001). Incidence of postoperative nausea and vomiting was higher in the TAPB group and no block-related complications were observed. Our data indicate that ESPB provides postoperative pain control at least as good as TAPB plus morphine, with less local anesthetic needed.

Perioperative Intravenous Amino Acid Infusion in Major Urologic Surgery.

Post-operative acute kidney injury (PO-AKI) is a serious complication that may occur after major abdominal surgery. The administration of intravenous perioperative amino acids (AAs) has been proven to increase kidney function and has some beneficial effects to prevent PO-AKI. The aim of this study was to establish if the perioperative infusion of AAs may reduce the incidence of PO-AKI in patients undergoing major urological minimally invasive surgery. From a total of 331 patients, the first 169 received perioperative crystalloid fluids and the following 162 received perioperative AA infusions. PO-AKIs were much higher in the crystalloid group compared to the AA group (34 vs. 17, p = 0.022) due to a lower incidence of KDIGO I and II in the AA group (14 vs. 30 p = 0.016). The AA group patients who developed a PO-AKI presented more risk factors compared to those who did not (2 (2-4) vs. 1 (1-2), p = 0.031) with a cut-off of 3 risk factors in the ROC curve (p = 0.007, sensitivity 47%, specificity 83%). The hospital length of stay was higher in the crystalloid group (p < 0.05) with a consequent saving in hospital costs. Perioperative AA infusion may help reduce the incidence of PO-AKI after major urological minimally invasive surgery.

Intracranial pressure for clinicians: it is not just a number.

BACKGROUND: Invasive intracranial pressure (ICP) monitoring is a standard practice in severe brain injury cases, where it allows to derive cerebral perfusion pressure (CPP); ICP-tracing can also provide additional information about intracranial dynamics, forecast episodes of intracranial hypertension and set targets for a tailored therapy to prevent secondary brain injury. Nevertheless, controversies about the advantages of an ICP clinical management are still debated. FINDINGS: This article reviews recent research on ICP to improve the understanding of the topic and uncover the hidden information in this signal that may be useful in clinical practice. Parameters derived from time-domain as well as frequency domain analysis include compensatory reserve, autoregulation estimation, pulse waveform analysis, and behavior of ICP in time. The possibility to predict the outcome and apply a tailored therapy using a personalised perfusion pressure target is also described. CONCLUSIONS: ICP is a crucial signal to monitor in severely brain injured patients; a bedside computer can empower standard monitoring giving new metrics that may aid in clinical management, establish a personalized therapy, and help to predict the outcome. Continuous collaboration between engineers and clinicians and application of new technologies to healthcare, is vital to improve the accuracy of current metrics and progress towards better care with individualized dynamic targets.

Perioperative Renal Ultrasonography of Arterio-to-Venous Coupling Predicts Postoperative Complications after Major Laparoscopic Urologic Surgery.

Point-of-care ultrasonography (POCUS) with concomitant venous and arterial Doppler assessment enables clinicians to assess organ-specific blood supply. To date, no studies have investigated the usefulness of including a comprehensive perioperative POCUS assessment of patients undergoing major laparoscopic surgery. The primary aim of the present study was to evaluate whether the combined venous and arterial renal flow evaluation, measured at different time points of perioperative period, may represent a clinically useful non-invasive method to predict postoperative acute kidney injury (AKI) after major laparoscopic urologic surgery. The secondary outcome was represented by the development of any postoperative complication at day 7. We included 173 patients, subsequently divided for analysis depending on whether they did (n = 55) or did not (n = 118) develop postoperative AKI or any complications within the first 7 days. The main results of the present study were that: (1) the combination of arterial hypoperfusion and moderate-to-severe venous congestion inferred by POCUS were associated with worst outcomes (respectively, HR: 2.993, 95% CI: 1.522-5.884 and HR: 8.124, 95% CI: 3.542-18, p < 0.001); (2) high intra-operative abdominal pressure represents the only independent determinant of postoperative severe venous congestion (OR: 1.354, 95% CI: 1.017-1.804, p = 0.038); (3) the overall number of complications relies on the balance between arterial inflow and venous outflow in order to ensure the adequacy of peripheral perfusion; and (4) the overall reliability of splanchnic perfusion assessment by Doppler is high with a strong inter-rater reliability (ICC: 0.844, 95% CI: 0.792-0.844). The concomitant assessment of arterial and venous Doppler patterns predicts postoperative complications after major laparoscopic urologic surgery and may be considered a useful ultrasonographic biomarker to stratify vulnerable patients at risk for development of postoperative complications.