Fuzzy logic control for intracranial pressure via continuous propofol sedation in a neurosurgical intensive care unit

Prediction of infarction volume and infarction growth rate in acute ischemic stroke

The prediction of infarction volume after stroke onset depends on the shape of the growth dynamics of the infarction. To understand growth patterns that predict lesion volume changes, we studied currently available models described in literature and compared the models with Adaptive Neuro-Fuzzy Inference System [ANFIS], a method previously unused in the prediction of infarction growth and infarction volume (IV). We included 67 patients with malignant middle cerebral artery [MMCA] stroke who underwent decompressive hemicraniectomy. All patients had at least three cranial CT scans prior to the surgery. The rate of growth and volume of infarction measured on the third CT was predicted with ANFIS without statistically significant difference compared to the ground truth [P = 0.489]. This was not possible with linear, logarithmic or exponential methods. ANFIS was able to predict infarction volume [IV3] over a wide range of volume [163.7–600 cm³] and time [22–110 hours]. The cross correlation [CRR] indicated similarity between the ANFIS-predicted IV3 and original data of 82% for ANFIS, followed by logarithmic 70%, exponential 63% and linear 48% respectively. Our study shows that ANFIS is superior to previously defined methods in the prediction of infarction growth rate (IGR) with reasonable accuracy, over wide time and volume range.

The clinical and CT features of rapid spontaneous resolution of traumatic acute subdural hematoma: A retrospective study of 14 cases

OBJECTIVE

Resolution of a traumatic acute subdural haematoma (ASDH) requires weeks or months. However, cases of rapid spontaneous resolution of ASDH within 72 hours after trauma have been reported. The purpose of this study was to obtain a better understanding of the clinical and CT features of cases of rapid resolution following traumatic ASDH.

METHOD

Between 2011-2014, the authors retrospectively collected data from 14 patients with rapid resolution of traumatic ASDH. The clinical data and CT findings of these cases were collected and analysed.

RESULTS

In 13 of the 14 patients, there was a rapid spontaneous resolution of the ASDH within 48 hours. The mean haematoma width of the second CT was significantly smaller than the width of the initial CT. A significantly marked resolution of the midline shift was observed in the second CT in all patients. The outcome was good in the majority of patients.

CONCLUSIONS

The acute fluctuation of ICP may drive the spontaneous rapid resolution and redistribution of ASDH. Patients with abnormal coagulant function may be more likely to experience rapid resolution of ASDH. A band of low density in the initial CT image may be a useful sign for rapid resolution of ASDH.

Fluctuation of intra-parenchymal cerebral pressure may drive the rapid spontaneous resolution of acute subdural hematoma

Acute subdural hematoma (ASDH) is a severe insult with a high mortality rate, and emergent surgical evacuation is recommended in the vast majority of such cases. Generally, resolution of the hemorrhage requires weeks and months in patients treated conservatively. However, numerous cases of rapid spontaneous resolution of ASDH, occurring within 72h after the trauma, have been reported to date in the literature. Several possible hypotheses have been suggested, primarily involving redistribution and dilution, or washing out the ASDH. In this study, we present the relevant images of such a case, review the mechanisms of the rapid spontaneous resolution in the literature, and also propose a new hypothesis to explain the occurrence of the rapid spontaneous resolution of ASDH. We indicate that the fluctuation of intra-parenchymal cerebral pressure that drives the rapid spontaneous resolution of ASDH.

Fuzzy logic: A "simple" solution for complexities in neurosciences?

Background:

Fuzzy logic is a multi-valued logic which is similar to human thinking and interpretation. It has the potential of combining human heuristics into computer-assisted decision making, which is applicable to individual patients as it takes into account all the factors and complexities of individuals. Fuzzy logic has been applied in all disciplines of medicine in some form and recently its applicability in neurosciences has also gained momentum.

Methods:

This review focuses on the use of this concept in various branches of neurosciences including basic neuroscience, neurology, neurosurgery, psychiatry and psychology.

Results:

The applicability of fuzzy logic is not limited to research related to neuroanatomy, imaging nerve fibers and understanding neurophysiology, but it is also a sensitive and specific tool for interpretation of EEGs, EMGs and MRIs and an effective controller device in intensive care units. It has been used for risk stratification of stroke, diagnosis of different psychiatric illnesses and even planning neurosurgical procedures.

Conclusions:

In the future, fuzzy logic has the potential of becoming the basis of all clinical decision making and our understanding of neurosciences.

Can fuzzy logic make things more clear?

Intensive care is a complex environment involving many signals, data and observations. Clinical decision support and artificial intelligence using fuzzy logic and closed loop techniques are methods that might help us to handle this complexity in a safe, effective and efficient way. Merouani and colleagues have performed a study using fuzzy logic and closed loop techniques to more effectively wean patients with sepsis from norepinephrine infusion.

Norepinephrine weaning in septic shock patients by closed loop control based on fuzzy logic

Introduction

The rate of weaning of vasopressors drugs is usually an empirical choice made by the treating in critically ill patients. We applied fuzzy logic principles to modify intravenous norepinephrine (noradrenaline) infusion rates during norepinephrine infusion in septic patients in order to reduce the duration of shock.

Methods

Septic patients were randomly assigned to norepinephrine infused either at the clinician's discretion (control group) or under closed-loop control based on fuzzy logic (fuzzy group). The infusion rate changed automatically after analysis of mean arterial pressure in the fuzzy group. The primary end-point was time to cessation of norepinephrine. The secondary end-points were 28-day survival, total amount of norepinephine infused and duration of mechanical ventilation.

Results

Nineteen patients were randomly assigned to fuzzy group and 20 to control group. Weaning of norepinephrine was achieved in 18 of the 20 control patients and in all 19 fuzzy group patients. Median (interquartile range) duration of shock was significantly shorter in the fuzzy group than in the control group (28.5 [20.5 to 42] hours versus 57.5 [43.7 to 117.5] hours; P < 0.0001). There was no significant difference in duration of mechanical ventilation or survival at 28 days between the two groups. The median (interquartile range) total amount of norepinephrine infused during shock was significantly lower in the fuzzy group than in the control group (0.6 [0.2 to 1.0] μg/kg versus 1.4 [0.6 to 2.7] μg/kg; P < 0.01).

Conclusions

Our study has shown a reduction in norepinephrine weaning duration in septic patients enrolled in the fuzzy group. We attribute this reduction to fuzzy control of norepinephrine infusion.

Trial registration

Trial registration: Clinicaltrials.gov NCT00763906.