Two computerized methods used to analyze intracranial pressure B waves: comparison with traditional visual interpretation.
ABSTRACT Slow and rhythmic oscillations in intracranial pressure (ICP), also known as B waves, have been claimed to be one of the best preoperative predictive factors in idiopathic adult hydrocephalus syndrome (IAHS). Definitions of B waves vary widely, and previously reported results must be treated with caution. The aims of the present study were to develop a definition of B waves, to develop a method to estimate the B-wave content in an ICP recording by using computer algorithms, and to validate these procedures by comparison with the traditional visual interpretation.
In eight patients with IAHS, ICP was continuously monitored for approximately 20 hours. The ICP B-wave activity as a percentage of total monitoring time (B%) was estimated by using visual estimation according to the definition given by Lundberg, and also by using two computer algorithms (Methods I and II). In Method I each individual wave was classified as a B wave or not, whereas Method II was used to estimate the B-wave content by evaluating the B-wave power in 10-minute blocks of ICP recordings.
The two computerized algorithms produced similar results. However, with the amplitude set to 1 mm Hg, Method I yielded the highest correlation with the visual analysis (r = 0.74). At least 5 hours of monitoring time was needed for an acceptable approximation of the B% in an overnight ICP recording. The advantages of using modern technology in the analysis of B-wave content of ICP are obvious and these methods should be used in future studies.
- SourceAvailable from: Angel Horcajadas Almansa[Show abstract] [Hide abstract]
ABSTRACT: Shunt dysfunction is a common situation in neurosurgery. Often symptoms, physical examination and radiology are not enough to set a diagnosis. ICP continuous monitoring is a safe and reliable tool that provides valuable information about CSF dynamics in these patients. Not only quantitative analysis is needed but also a qualitative one that enables pathological waves identification, because high amplitude B waves are strongly related to shunt dysfunction. In this paper experience about ICP continuous monitoring in patients with shunt dysfunction suspect is presented. Quantitative and qualitative data analysis led to a correct diagnosis, improving all the patients treated according to this criterion. An intraparenchymatous Camino® sensor and neuroPICture software (developed by first author) for data collection and graphic representation were used. Complications related to monitoring were absent and graphics obtained useful for qualitative analysis.Neurocirugia (Asturias, Spain) 08/2011; 22(4):310-23. · 0.32 Impact Factor
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ABSTRACT: Cerebrospinal fluid (CSF) pressure-volume compensation may change over time as part of normal ageing, where the resistance to CSF outflow increases and the formation of CSF decreases with age. Is CSF compensation dependent on duration of symptoms in idiopathic normal pressure hydrocephalus (iNPH)? We investigated 92 patients presenting with iNPH. Mean age was 73 (range 47-86). There were 60 men and 32 women. They all presented with gait disturbance and ventricular dilatation. Memory deficit occurred in 72% and urinary incontinence in 52% of patients. All patients underwent computerized CSF infusion tests. Sixty-four shunted patients were available for follow-up, and their improvement was expressed using the NPH score. Mean intracranial pressure (ICP) was 10.1±5.1 mmHg, and mean resistance to CSF outflow was 17.3±5.2 mmHg/(ml/min). Mean duration of symptoms was 24±19 months (range from 2 weeks to 86 months). Baseline ICP, magnitude of ICP pulse waveform, brain compliance and improvement after shunting (72% of patients improved) did not exhibit any dependency on the duration of symptoms. The resistance to CSF outflow showed a strong tendency to decrease in time with the duration of symptoms beyond 2 years (R= -0.702; P<0.005). This is a preliminary observation, and it suggests that for patients with duration of symptoms longer than 2-3 years, the threshold for normal resistance to CSF outflow should be duration-adjusted.Acta Neurologica Scandinavica 06/2011; 123(6):414-8. · 2.44 Impact Factor
Article: Intracranial pressure monitoring[Show abstract] [Hide abstract]
ABSTRACT: Maintaining adequate cerebral perfusion is the primary goal of management of patients with traumatic brain injury and intracranial pressure is one of the major factors affecting cerebral blood flow. Intracranial pressure measurement is necessary to confirm or exclude intracranial hypertension and to determine cerebral perfusion pressure. It also helps guide therapy in head injury patients. There is a substantial body of evidence to support the use of intracranial pressure monitoring and it is now a central part of the critical care management of the severely brain injured patient. This is a review of intracranial pressure monitoring with specific reference to traumatic brain injury. A brief description of the physiology of cerebral blood flow and intracranial pressure is given followed by the principles of measurement, indications, techniques and problems associated with intracranial pressure monitoring.Current Anaesthesia and Critical Care 10/2003; 14(5–6):229-235.