Intracranial Pressure Monitoring: Invasive versus Non-Invasive Methods—A Review

Monitoring of intracranial pressure (ICP) has been used for decades in the fields of neurosurgery and neurology. There are multiple techniques: invasive as well as noninvasive. This paper aims to provide an overview of the advantages and disadvantages of the most common and well-known methods as well as assess whether noninvasive techniques (transcranial Doppler, tympanic membrane displacement, optic nerve sheath diameter, CT scan/MRI and fundoscopy) can be used as reliable alternatives to the invasive techniques (ventriculostomy and microtransducers). Ventriculostomy is considered the gold standard in terms of accurate measurement of pressure, although microtransducers generally are just as accurate. Both invasive techniques are associated with a minor risk of complications such as hemorrhage and infection. Furthermore, zero drift is a problem with selected microtransducers. The non-invasive techniques are without the invasive methods' risk of complication, but fail to measure ICP accurately enough to be used as routine alternatives to invasive measurement. We conclude that invasive measurement is currently the only option for accurate measurement of ICP

Serial soluble neurofilament heavy chain in plasma as a marker of brain injury after cardiac arrest

ABSTRACT: INTRODUCTION: Induced hypothermia has been shown to improve outcome after cardiac arrest, but early prognostication is hampered by the need for sedation. Here we tested whether a biomarker for neurodegeneration, the neurofilament heavy chain (NfH), may improve diagnostic accuracy in the first days after cardiac arrest. METHODS: This prospective study included 90 consecutive patients treated with hypothermia after cardiac arrest. Plasma levels of phosphorylated NfH (SMI35) were quantified using standard ELISA over a period of 72 h after cardiac arrest. The primary outcome was the dichotomized Cerebral Performance Categories scale (CPC). A best CPC 1-2 during 6 months follow-up was considered a good outcome, a best CPC of 3-4 a poor outcome. Receiver operator characteristics and area under the curve were calculated. RESULTS: The median age of the patients was 65 years, and 63 (70%) were male. A cardiac aetiology was identified in 62 cases (69%). 77 patients (86%) had out-of-hospital cardiac arrest. The outcome was good in 48 and poor in 42 patients. Plasma NfH levels were significantly higher 2 and 36 hours after cardiac arrest in patients with poor outcome (median 0.28 ng/mL and 0.5 ng/mL, respectively) compared to those with good outcome (0 ng/mL, p = 0.016, p < 0.005, respectively). The respective AUC were 0.72 and 0.71. CONCLUSIONS: Plasma NfH levels correlate to neurological prognosis following cardiac arrest. In this study, 15 patients had neurological co-morbidities and there was a considerable overlap of data. As such, neurofilament should not be used for routine neuroprognostication until more data are available

Risk factors for aneurysmal subarachnoid haemorrhage: the Tromsø study

Methods: The Tromsø health study is a population based survey of risk factors for cardiovascular disease in 27 161 subjects. 26 cases of aneurysmal SAH were identified in which risk factors were registered before the bleeding. Four age and sex matched controls were selected for each case. A backward logistic regression analysis was conducted and odds ratios (ORs) for significant risk factors were calculated. Systolic and diastolic blood pressure, cigarette smoking habits, serum concentrations of lipoproteins, body mass index, and coffee consumption were analysed. Results: The crude annual incidence rate of aneurysmal SAH was 8.84/100 000 population. The proportion of current smokers was significantly (p = 0.003) higher in patients with SAH (73.1%) than in controls (41.3%). Drinking more than five cups of coffee per day was more common among patients (85%) than controls (59%) (p = 0.004). Mean (SD) systolic blood pressure was higher (p = 0.017) in patients (154.0 (32.5)) than in controls (136.3 (23.3)). Regression analysis showed that cigarette smoking (p = 0.04), systolic blood pressure (p < 0.0001), and coffee consumption (p = 0.004) were independent risk factors for SAH. The OR of current smokers versus never smokers was 4.55 (95% confidence interval (CI) 1.08 to 19.30) and the OR of drinking more than five cups of coffee a day was 3.86 (95% CI 1.01 to 14.73). The OR of an increase in systolic blood pressure of 20 mm Hg was 2.46 (95% CI 1.52 to 3.97). Conclusions: Cigarette smoking and hypertension are significant independent risk factors for aneurysmal SAH. A high coffee consumption may also predispose patients to aneurysmal SAH