Hyponatremia, volume status and blood pressure following aneurysmal subarachnoid hemorrhage

Patients who survive an aneurysmal subarachnoid hemorrhage (SAH) are endangered by complications, which especially occur during the first weeks after the hemorrhage. These complications have a high mortality and morbidity, and the outcome of patients with SAH will improve if these complications can be prevented or if the neurological deterioration caused by these complications can be reversed. To achieve this, it is of the utmost importance to distinguish between the different causes of deterioration after SAH. For instance, if a patient has an impaired level of consciousness a few days after the initial hemorrhage, while there were no abnormalities during the days before, this patient might have had a rebleed, cerebral ischemia, hydrocephalus or other, less common complications. In our department all such patients were under continuous observation in an intensive care unit. If a deterioration had occurred, the time course was documented, the patient was examined and a CT scan was repeated. The serum sodium levels were also measured in these patients, since it is known that hyponatremia may occur after SAH and can lead to neurological deficits. A low serum sodium level never appeared to be the direct cause of a deterioration, probably because the sodium levels decreased gradually and were never under 120 mmol/liter. However, we had the impression that patients with hyponatremia did worse than others. I decided to investigate whether SAH patients with hyponatremia did indeed have a particularly poor outcome, how and why hyponatremia develops and how it can be prevented. These questions are the subject of this thesis

ARFIMA-GARCH modeling of HRV: Clinical application in acute brain injury

In the last decade, several HRV based novel methodologies for describing and assessing heart rate dynamics have been proposed in the literature with the aim of risk assessment. Such methodologies attempt to describe the non-linear and complex characteristics of HRV, and hereby the focus is in two of these characteristics, namely long memory and heteroscedasticity with variance clustering. The ARFIMA-GARCH modeling considered here allows the quantification of long range correlations and time-varying volatility. ARFIMA-GARCH HRV analysis is integrated with multimodal brain monitoring in several acute cerebral phenomena such as intracranial hypertension, decompressive craniectomy and brain death. The results indicate that ARFIMA-GARCH modeling appears to reflect changes in Heart Rate Variability (HRV) dynamics related both with the Acute Brain Injury (ABI) and the medical treatments effects. (c) 2017, Springer International Publishing AG

Prospective study of sentinel headache in aneurysmal subarachnoid haemorrhage.

Retrospective surveys of patients with subarachnoid haemorrhage suggest that minor episodes with sudden headache (warning leaks) may precede rupture of an aneurysm, and that early recognition and surgery might lead to improved outcome. We studied 148 patients with sudden and severe headache (possible sentinel headache) seen by 252 general practitioners in a 5-year period in the Netherlands. Subarachnoid haemorrhage was the cause in 37 patients (25%) (proven aneurysm in 21, negative angiogram in 6, no angiogram done in 6, sudden headache followed by death in 4). 103 patients had headache as the only symptom, 12 of whom proved to have subarachnoid haemorrhage (6 with a ruptured aneurysm). Previous bouts of sudden headache had occurred in only 2. Other serious neurological conditions were diagnosed in 18. In the remaining 93, no underlying cause of headache was found; follow-up over 1 year showed no subsequent subarachnoid haemorrhage or sudden death. In this cohort, acute, severe headache in general practice indicated a serious neurological disorder in 37% (95% CI 29-45%), and subarachnoid haemorrhage in 25% (18-32%). 12% (5-18%) of those with headache as the only symptom. The notion of warning leaks as a less serious variant of subarachnoid haemorrhage is not supported by this study. Early recognition of subarachnoid haemorrhage is important but will probably have only limited impact on the outcome in the general population. (aut. ref.