A Novel Noninvasive Technique for Intracranial Pressure Waveform Monitoring in Critical Care

Background: We validated a new noninvasive tool (B4C) to assess intracranial pressure waveform (ICPW) morphology in a set of neurocritical patients, correlating the data with ICPW obtained from invasive catheter monitoring. Materials and Methods: Patients undergoing invasive intracranial pressure (ICP) monitoring were consecutively evaluated using the B4C sensor. Ultrasound-guided manual internal jugular vein (IJV) compression was performed to elevate ICP from the baseline. ICP values, amplitudes, and time intervals (P2/P1 ratio and time-to-peak [TTP]) between the ICP and B4C waveform peaks were analyzed. Results: Among 41 patients, the main causes for ICP monitoring included traumatic brain injury, subarachnoid hemorrhage, and stroke. Bland–Altman’s plot indicated agreement between the ICPW parameters obtained using both techniques. The strongest Pearson’s correlation for P2/P1 and TTP was observed among patients with no cranial damage (r = 0.72 and 0.85, respectively) to the detriment of those who have undergone craniotomies or craniectomies. P2/P1 values of 1 were equivalent between the two techniques (area under the receiver operator curve [AUROC], 0.9) whereas B4C cut-off 1.2 was predictive of intracranial hypertension (AUROC 0.9, p < 000.1 for ICP > 20 mmHg). Conclusion: B4C provided biometric amplitude ratios correlated with ICPW variation morphology and is useful for noninvasive critical care monitoring.

A Novel Noninvasive Technique for Intracranial Pressure Waveform Monitoring in Critical Care

We validated a new noninvasive tool (B4C) to assess intracranial pressure waveform (ICPW) morphology in a set of neurocritical patients, correlating the data with ICPW obtained from invasive catheter monitoring. Materials and Methods: Patients undergoing invasive intracranial pressure (ICP) monitoring were consecutively evaluated using the B4C sensor. Ultrasound-guided manual internal jugular vein (IJV) compression was performed to elevate ICP from the baseline. ICP values, amplitudes, and time intervals (P2/P1 ratio and time-to-peak [TTP]) between the ICP and B4C waveform peaks were analyzed. Results: Among 41 patients, the main causes for ICP monitoring included traumatic brain injury, subarachnoid hemorrhage, and stroke. Bland-Altman&rsquo;s plot indicated agreement between the ICPW parameters obtained using both techniques. The strongest Pearson&rsquo;s correlation for P2/P1 and TTP was observed among patients with no cranial damage (r = 0.72 and 0.85, respectively) in detriment of those who have undergone craniotomies or craniectomies. P2/P1 values of 1 were equivalent between the two techniques (area under the receiver operator curve [AUROC], 0.9) whereas B4C cut-off 1.2 was predictive of intracranial hypertension (AUROC 0.9, p &lt; 000.1 for ICP &gt; 20 mmHg). Conclusion: B4C provided biometric amplitude ratios correlated with ICPW variation morphology and is useful for noninvasive critical care monitoring.

Use of non-invasive intracranial pressure pulse waveform to monitor patients with End-Stage Renal Disease (ESRD)

End-stage renal disease (ESRD) is treated mainly by hemodialysis, however, hemodialysis is associated with frequent complications, some of them involve the increased intracranial pressure. In this context, monitoring the intracranial pressure of these patients may lead to a better understanding of how intracranial pressure morphology varies with hemodialysis. This study aimed to follow-up patients with ESRD by monitoring intracranial pressure before and after hemodialysis sessions using a noninvasive method. We followed-up 42 patients with ESRD in hemodialysis, for six months. Noninvasive intracranial pressure monitoring data were obtained through analysis of intracranial pressure waveform morphology, this information was uploaded to Brain4care® cloud algorithm for analysis. The cloud automatically sends a report containing intracranial pressure parameters. In total, 4881 data points were collected during the six months of follow-up. The intracranial pressure parameters (time to peak and P2/P1 ratio) were significantly higher in predialysis when compared to postdialysis for the three weekly sessions and throughout the follow-up period (p<0.01) data showed general improvement in brain compliance after the hemodialysis session. Furthermore, intracranial pressure parameters were significantly higher in the first weekly hemodialysis session (p<0.05). In conclusion, there were significant differences between pre and postdialysis intracranial pressure in patients with ESRD on hemodialysis. Additionally, the pattern of the intracranial pressure alterations was consistent over time suggesting that hemodialysis can improve time to peak and P2/P1 ratio which may reflect in brain compliance.

Prospective study on intracranial pressure waveform morphology and its relationship with the development of obesity in rats

Obesity accumulates fat in the body may cause hypertension and change intracranial pressure waveform morphology (ICP). However, not clear how and when it occurs. Thus, our objective was to evaluate the ICP waveform morphology and P2/P1 ratio during the development of obesity. Sixteen 45-day-old male Wistar rats, after 60 days of adaptation were divided into non-obese (NOB, n = 7) and obese (OB, n = 9). The OB group received a high-fat diet and the NOB group received a standard diet for 24 weeks. ICP, body composition, blood pressure (BP), and heart rate(HR) were assessed every 4 weeks. Two-Way ANOVA was used for the area under the curve with Bonferroni's test, or Student's t-test for BP, and HR. Body mass(BM) and body fat(BF) and fat-free mass(FFM) were higher in OB rats. There was no difference in BP, but there was a difference in HR, greater in OB. The ICP decreased by NOB. These results suggest that the increase in BM and BF caused obesity, and BM can explain the increase in FFM. Although we did not find pathological states of ICP, NOB demonstrated better brain compliance, and the upward trend in the P2 waveform in OB may indicate impairment to the ICP of OB rats.

Case Report: Untreatable Headache in a Child With Ventriculoperitoneal Shunt Managed by Use of New Non-invasive Intracranial Pressure Waveform

brain4care, a new Food and Drug Administration (FDA)-cleared non-invasive sensor that monitors intracranial pressure waveforms, was used in a 13-year-old girl who presented with untreatable headaches. The patient had a history of craniopharyngioma resection and a ventriculoperitoneal shunt placement 7 years prior to the use of the device. Secondary obstructive hydrocephalus was also a present factor in the case. The hypothesis was that due to the hydrocephalus, the child presented chronic headaches and needed constant readjustment into the ventriculoperitoneal shunt to regulate the cerebrospinal fluid inside her ventricles in order to control the patient's intracranial pressure (ICP). The device was chosen considering the risks to submit a patient into the regular invasive method to measure ICP. It was identified that the device could also indicate altered intracranial compliance due to the ratio between the P1 and P2 amplitudes (P2/P1 ratio &gt; 1).

Intracranial Pressure Waveform: History, Fundamentals and Applications in Brain Injuries

Intracranial pressure (ICP) can be analyzed for its absolute value, usually in mmHg or cmH2O, its tendency over time and the waveform of its pulse. This chapter will focus on the waveform of the ICP pulse (ICPwf), already observed since 1881, and for a long time not understood. Studies conducted in recent decades show the correlation between the ICPwf and intracranial compliance (ICC), another important clinical parameter added to the practice in the second half of the last century. ICC allows physicians early analyzing patients’ neurological conditions related to disorders resulting from variations in cerebrospinal fluid (CSF), blood and intracranial tissue volumes. This chapter is an invitation to dive into the history and development of ICPwf analysis, clinical uses already adopted and others still under study.

Use of non-invasive intracranial pressure pulse waveform to monitor patients with End-Stage Renal Disease (ESRD) Intracranial pressure in patients with ESRD

End-stage renal disease (ESRD) is treated mainly by hemodialysis, however, hemodialysis is associated with frequent complications, some of them involve the increased intracranial pressure. In this context, monitoring the intracranial pressure of these patients may lead to a better understanding of how intracranial pressure morphology varies with hemodialysis. This study aimed to follow-up patients with ESRD by monitoring intracranial pressure before and after hemodialysis sessions using a noninvasive method. We followed-up 42 patients with ESRD in hemodialysis, for six months. Noninvasive intracranial pressure monitoring data were obtained through analysis of intracranial pressure waveform morphology, this information was uploaded to Brain4care® cloud algorithm for analysis. The cloud automatically sends a report containing intracranial pressure parameters. In total, 4881 data points were collected during the six months of follow-up. The intracranial pressure parameters (time to peak and P2/P1 ratio) were significantly higher in predialysis when compared to postdialysis for the three weekly sessions and throughout the follow-up period (p<0.01) data showed general improvement in brain compliance after the hemodialysis session. Furthermore, intracranial pressure parameters were significantly higher in the first weekly hemodialysis session (p<0.05). In conclusion, there were significant differences between pre and postdialysis intracranial pressure in patients with ESRD on hemodialysis. Additionally, the pattern of the intracranial pressure alterations was consistent over time suggesting that hemodialysis can improve time to peak and P2/P1 ratio which may reflect in brain compliance.