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- Lindgren, Cecilia, 1958-
(författare)
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Subarachnoid haemorrhage : clinical and epidemiological studies
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Subarachnoid haemorrhage (SAH) is a severe stroke that in 85% of all cases is caused by the rupture of a cerebral aneurysm. The median age at onset is 50-55 years and the overall mortality is approximately 45%.Sufficient cortisol levels are important for survival. After SAH hypothalamic/pituitary blood flow may be hampered this could result in inadequate secretion of cortisol. SAH is also associated with a substantial inflammatory response. Asymmetric dimethyl arginine (ADMA), an endogenous inhibitor of nitric oxide synthase, mediates vasoconstriction and increased ADMA levels may be involved in inflammation and endothelial dysfunction. Continuous electroencephalogram (EEG) monitoring can be used to detect non-convulsive seizures, leading to ischemic insults in sedated SAH patients. Elevated ADMA levels are risk factors for vascular diseases. Vascular disease has been linked to stress, inflammation and endothelial dysfunction. SAH possesses all those clinical features and theoretically SAH could thus induce vascular disease.Aims: 1. Assess cortisol levels after SAH, and evaluate associations between cortisol and clinical parameters. 2. Assess ADMA levels and arginine/ADMA ratios after SAH and evaluate associations between ADMA levels and arginine/ADMA ratios with severity of disease, co-morbidities, sex, age and clinical parameters. 3. Investigate occurrence of subclinical seizures in sedated SAH patients. 4. Evaluate if patients that survive a SAH ≥ one year have an increased risk of vascular causes of death compared to a normal population.Results: Continuous infusion of sedative drugs was the strongest predictor for a low (<200 nmol/L) serum cortisol. The odds ratio for a sedated patient to have a serum cortisol < 200 nmol/L was 18.0 times higher compared to an un-sedated patient (p < 0.001). Compared to admission values, 0-48 hours after SAH, CRP increased significantly already in the time-interval 49-72 hours (p<0.05), peaked in the time-interval 97-120 hours after SAH and thereafter decreased. ADMA started to increase in the time-interval 97-120 hours (p<0.05). ADMA and CRP levels were significantly higher, and arginine/ADMA ratios were significantly lower in patients with a more severe condition (p<0.05). Epileptic seizure activity, in sedated SAH patients, was recorded in 2/28 (7.1%) patients during 5/5468 (0.09%) hours of continuous EEG monitoring. Cerebrovascular disease was significantly more common as a cause of death in patients that had survived a SAH ≥ one year, compared to the population from the same area (p<0.0001).Conclusions: Continuous infusion of sedative drugs was associated with low (<200 nmol/L) cortisol levels. ADMA increased significantly after SAH, after CRP had peaked, indicating that endothelial dysfunction, with ADMA as a marker, is induced by a systemic inflammation. Patients with a more severe condition had significantly higher ADMA and CRP levels, and significantly lower arginine/ADMA ratio. Continuous sedation in sedated SAH patients seems to be beneficial in protecting from subclinical seizures. Cerebrovascular causes of death are more common in SAH survivors.
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| 2. |
- Brorsson, Camilla, 1967-
(författare)
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Trauma - logistics and stress response
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Trauma is a major cause of death and disability. Adverse events, such as prolonged prehospital time, hypoxia, hypotension and/or hyperventilation have been reported to correlate to poor outcome.Adequate cortisol levels are essential for survival after major trauma. In hypotensive critically ill patients, lack of sufficient amount of cortisol can be suspected, and a concept of critical illness related corticosteroid insufficiency has been proposed. Corticosteroid therapy has many adverse effects in critically ill patients and should only be given if life-saving. Correct measurement of serum cortisol levels is important but difficult in critically ill patients with capillary leakage. Estimation of the free and biologically active cortisol is preferable. In serum less than 10% of cortisol is free and biologically active and not possible to measure with routine laboratory methods. Salivary cortisol can be used as a surrogate for free cortisol, but salivary production is reduced in critically ill patients. Liver resection could reduce cortisol levels due to substrate deficiency.Aims: 1. Evaluate the occurrence of early adverse events in patients with traumatic brain injury and relate them to outcome. 2. Assess cortisol levels over time after trauma and correlate to severity of trauma, sedative/analgesic drugs and cardiovascular function. 3. Evaluate if saliva stimulation could be performed without interfering with salivary cortisol levels. 4. Assess cortisol levels over time after liver resection in comparison to other major surgery.Results: There was no significant correlation between prehospital time ³60 minutes, hypoxia (saturation <95%), hypotension (systolic blood pressure <90 mmHg), or hyperventilation (ETCO2 <4.5 kPa) and a poor outcome (Glasgow Outcome Scale 1-3) in patients with traumatic brain injury. Cortisol levels decreased significantly over time after trauma, but there was no correlation between low (<200 nmol/L) serum cortisol levels and severity of trauma.Infusion of sedative/analgesic drugs was the strongest predictor for a low (<200 nmol/L) serum cortisol. The odds ratio for low serum cortisol levels (<200 nmol/L) was 8.0 for patients receiving continuous infusion of sedative/analgesic drugs. There was no significant difference between unstimulated and stimulated salivary cortisol levels (p=0.06) in healthy volunteers. Liver resection was not associated with significantly lower cortisol levels compared to other major surgery.Conclusion: There was no significant correlation between early adverse events and outcome in patients with traumatic brain injury. Cortisol levels decreased significantly over time in trauma patients. Low cortisol levels (<200 nmol/L) were significantly correlated to continuous infusion of sedative/analgesic drugs. Saliva stimulation could be performed without interfering with salivary cortisol levels. Liver resection was not associated with low cortisol levels compared to other major surgery.
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| 3. |
- Nyberg, Christoffer, 1977-
(författare)
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Metabolic and Endocrine Response in the Acute Stage of Subarachnoid Hemorrhage
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The rupture of an aneurysm in subarachnoid hemorrhage (SAH) is a dramatic event causing a severe impact on the brain and a transient or permanent ischemic condition. Several types of responses to meet the challenges of SAH have been found in the acute phase, including activation of the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system, elevated levels of brain natriuretic peptide (BNP), and disturbances in cerebral and systemic metabolism.Cerebral metabolism and the endocrine stress response in the ultra-early phase was investigated in a novel porcine model of SAH in which autologous blood was injected to the anterior skull base. Early activation of the HPA axis was found with rapid elevation of adrenocorticotrophic hormone, cortisol and aldosterone. The peak values of these hormones were early and may be impossible to catch in patients. There were indications of a sympathetic nervous response with excretion of catecholamines in urine as well as plasma chromogranin-A elevation. Cerebral microdialysis suggested immediate substrate failure followed by hypermetabolism of glucose. The animal model seems suited for further studies of aneurysmal SAH.NT-proBNP was investigated in 156 patients with SAH, there was a dynamic course with increasing levels during the first 4 days of the disease. Factors predicting high NT-proBNP load included female sex, high age, high Troponin-I at admission, angiographic finding of an aneurysm and worse clinical condition at admission. High levels of NT-proBNP were correlated to factors indicating a more severe disease, suggesting the initial injury in aneurysmal SAH is an important factor in predicting high NT-proBNP during the acute stage of the disease.Measurements with indirect calorimetry were performed daily during the first week after SAH on 32 patients with SAH. There was a dynamic course with increasing energy expenditure (EE) the first week after SAH. Comparisons with three predictive equations indicated that measured EE generally is higher than predicted, but considerable variation exists within and between patients, indicating that prediction of EE in SAH is difficult.Altogether, the studies demonstrate a complicated response in acute SAH that needs to be further studied to increase possibility of good outcome in SAH patients.
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| 4. |
- Rodling Wahlström, Marie, 1960-
(författare)
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Severe cerebral emergency : aspects of treatment and outcome in the intensive care patient
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Severe Traumatic Brain Injury (TBI) and aneurysmal Subarachnoid Hemorrhage (SAH) are severe cerebral emergencies. They are common reasons for extensive morbidity and mortality in young people and adults in the western world. This thesis, based on five clinical studies in patients with severe TBI (I-IV) and SAH (V), is concentrated on examination of pathophysiological developments and of evaluation of therapeutic approaches in order to improve outcome after cerebral emergency. The treatment for severe TBI patients at Umeå University Hospital, Sweden is an intracranial pressure (ICP)-targeted therapy according to “the Lund-concept”. This therapy is based on physiological principles for cerebral volume regulation, in order to preserve a normal cerebral microcirculation and a normal ICP. The main goal is to avoid development of secondary brain injuries, thus avoiding brain oedema and worsened microcirculation. Study I is evaluating retrospectively 41 children with severe TBI, from 1993 to 2002. The boundaries of the ICP-targeted protocol were obtained in 90%. Survival rate was 93%, and favourable outcome (Glasgow Outcome Scale, score 4+5) was 80%. Study II is retrospectively analysing fluid administration and fluid balance in 93 adult patients with severe TBI, from 1998 to 2001.The ICP-targeted therapy used, have defined fluid strategies. The total fluid balance was positive day one to three, and negative day four to ten. Colloids constituted 40-60% of total fluids given/day. Severe organ failure was evident for respiratory insufficiency and observed in 29%. Mortality within 28 days was 11%. Study III is a prospective, randomised, double-blind, placebo-controlled clinical trial in 48 patients with severe TBI. In order to improve microcirculation and prevent oedema formation, prostacyclin treatment was added to the ICP-targeted therapy. Prostacyclin is endogenously produced, by the vascular endothelium, and has the ability to decrease capillary permeability and vasodilate cerebral capillaries. Prostacyclin is an inhibitor of leukocyte adhesion and platelet aggregation. There was no significant difference between prostacyclin or placebo groups in clinical outcome or in cerebral microdialysis markers such as lactatepyruvate ratio and brain glucose levels. Study IV is part of the third trial and focus on the systemic release of pro-inflammatory mediators that are rapidly activated by trauma. The systemically released pro-inflammatory mediators, interleukin-6 and CRP were significantly decreased in the prostacyclin group versus the placebo group. Study V is a prospective pilot study which analyses asymmetric dimethylarginine (ADMA) concentrations in serum from SAH patients. Acute SAH patients have cerebral vascular, systemic circulatory and inflammatory complications. ADMA is a marker in vascular diseases which is correlated to endothelial dysfunction. ADMA concentrations in serum were significantly elevated seven days after the SAH compared to admission and were still elevated at the three months follow-up. Our results show overall low mortality and high favourable outcome compared to international reports on outcome in severe TBI patients. Prostacyclin administration does not improve cerebral metabolism or outcome but significantly decreases the levels of pro-inflammatory mediators. SAH seems to induce long-lasting elevations of ADMA in serum, which indicates persistent endothelial dysfunction. Endothelial dysfunction may influence outcome after severe cerebral emergencies.
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