| 1. |
- Johansson, Joakim, 1973-
(author)
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Function of granulocytes after burns and trauma, associations with pulmonary vascular permeability, acute respiratory distress syndrome, and immunomodulation
- 2013
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Doctoral thesis (other academic/artistic)abstract
- Background: Our innate immunesystem protects us from infections but, since its methods is not all specific for microorganisms, may also induce collateral damage.Severe physical injury often proved deadly throughout evolution. Such injuries may induce massive collateral damage. Nowadays we can initiate advanced critical care for affected patients and save them from imminent trauma-related death. We are therefore faced with the fact that the collateral damage from the immune system may pose a major threat to the patient, the pathophysiology of which is not amenable to direct medical treatment and which leaves us with only passive supportive measures.In this thesis we investigated the role of leucocytes under such circumstances.Our main aim was to understand better the role of leucocytes in the development of increased vascular permeability after burns and trauma.More specifically we investigated the impact of an injury on the function of leucocytes such as the dynamic change of certain cell-surface receptors on the leucocytes and in their numbers and immature forms. We wanted to find out if the increased pulmonary vascular permeability after a burn could be mediated through heparin binding protein (HBP) released from granuloctes, and whether HBP could be used as a biomarker for respiratory failure after trauma. We also wanted to confirm the possible role of histamine as a mediator of the systemic increase in vascular permeability after burns.Methods: The dynamic change of cell-surface receptors was measured by flow-acquired cytometer scanning (FACS) on blood samples taken after burns. The concentrations of HBP after a burn and mechanical trauma were analysed in plasma. Pulmonary vascular permeability after a burn was assessed using transpulmonary thermodilution. The histamine turnover after a burn was assessed with high performance liquid chromatography (HPLC) for concentrations of histamine and methylhistamine in urine.Results: We confirmed earlier investigations showing altered expression of receptors on leucocytes after a burn, receptors intimately associated with leucocyte functions (study I). In a pilot study of 10 patients we measured plasma concentrations of HBP and found them to be increased soon after a burn (study II). This finding was not confirmed in a larger, more extensive and specific study of 20 patients. We did, however, find an association between alterations in the number of leucocytes soon after a burn and pulmonary vascular permeability, indicating that they had a role in this process (study III).In another study of trauma (non burn) we found an association between the concentration of HBP in early plasma-samples after injury and the development of ARDS, indicating that granulocytes and HBP have a role in its aetiology (study IV).We found a small increase in urinary histamine and normal urinary methylhistamine concentrations but had anticipated a distinct increase followed by a decrease after reading the current papers on the subject. This indicates that the role of histamine as a mediator of increased vascular permeability after burns may have been exaggerated (study V).Conclusions: We conclude that leucocytes are affected by burns and trauma, and it is likely that they contribute to the development of respiratory failure and acute respiratory distress syndrome (ARDS). HBP is a candidate biomarker for the early detection of ARDS after trauma, and the white blood count (WBC) is a useful biomarker for the detection of decreased oxygenation soon after a burn.
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| 2. |
- Nilsson, Andreas, 1974-
(author)
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Patient-controlled sedation in procedural care
- 2014
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Doctoral thesis (other academic/artistic)abstract
- The need for procedural sedation is extensive and on the increase in numbers of patients. Minor treatments or diagnostic procedures are being performed with inadequate sedation or even without any sedatives or analgesics. Also, sedation techniques that support advanced, high-quality, in-patient care procedures representing easy performance and rapid recovery are requested for increased effectiveness. In this doctoral thesis, patient-controlled sedation (PCS) using propofol and alfentanil for surgical and diagnostic procedures was studied. The overall aim was to study aspects of safety, procedural feasibility and patients’ experiences. The main hypothesis was that PCS using only propofol is a safe and effective method for the induction and maintenance of moderate procedural sedation. The studies included were prospective, interventional, and in some cases, randomized and double-blinded.Data on cardiopulmonary changes, level of conscious sedation (bispectral index and Observer’s assessment of alertness/sedation [OAA/S]), pain, discomfort, anxiety, nausea (visual analogue scales), interventions performed by nurse anaesthetists, surgeons’ evaluation of feasibility, procedure characteristics, recovery (Aldrete score) and pharmacokinetic simulation of concentrations of drugs at the effect site supported the analysis and comparison between PCS and anaesthetist-controlled sedation and propofol PCS with or without alfentanil.PCS can be adjusted to cover a broad range of areas where sedation is needed, which, in this thesis, included burn care, gynaecological out-patient surgery and endoscopic procedures for the diagnosis and treatment of diseases in the bile ducts (endoscopic retrograde cholangiopancreatography [ERCP]). PCS for burn wound treatment demands the addition of alfentanil, but still seems to be safe. PCS was preferred by the patients instead of anaesthetist-controlled sedation. The addition of alfentanil to PCS as an adjunct to gynaecological surgical procedures also using local anaesthesia increases the surgeon’s access to the patients, but impairs safety. Apnoea and other such conditions requiring interventions to restore respiratory function were seen in patients receiving both alfentanil and propofol for PCS. Patients’ experiencing perioperative pain and anxiety did not explain the effect-site concentrations of drugs. Different gynaecological procedures and patients’ weights seemed to best explain the concentrations. For discomfort and pain during the endoscopic procedure (ERCP), propofol PCS performs almost the same as anaesthetist-performed sedation. Overall, as part of the pre-operative procedures, PCS does not seem to be time-consuming. In respect to the perioperative perspective, PCS supports rapid recovery with a low incidence of tiredness, pain, and post-operative nausea and vomiting (PONV).The data suggest that PCS further needs to be adapted to the patient, the specific procedure and the circumstances of sedation for optimal benefit and enhanced safety.
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| 3. |
- Berkius, Johan, 1960-
(author)
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Intensive care in chronic obstructive pulmonary disease : treatment with non-invasive ventilation and long-term outcome
- 2013
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Doctoral thesis (other academic/artistic)abstract
- Background: Chronic obstructive pulmonary disease (COPD) is a major cause of chronic morbidity and mortality throughout the world. When we began this project our knowledge about the outcome of COPD patients admitted to the ICU in Sweden was scarce.Aims: To investigate the characteristics, survival and health-related quality of life (HRQL) of COPD patients admitted to Swedish ICUs. To investigate how ICU personnel decide whether to use invasive or non-invasive ventilatory treatment (NIV) of the newly admitted COPD patient in need of ventilatory support. To investigate outcome according to mode of ventilation.Material and methods: Detailed data, including HRQL during recovery, from COPD patients admitted to ICUs that participated in the Swedish intensive care registry were analysed. A questionnaire was distributed to personnel in 6 of the participating ICUs in order to define factors deemed important in making the choice between invasive and non-invasive ventilation immediately after admission. The answers were analysed.Results: The proportion of COPD patients admitted to Swedish ICUs in need of ventilatory support is 1.3-1.6 % of all admissions. The patients are around 70 years-old and are severely ill on admission, with high respiratory rates and most have life-threatening disturbances in their acid-base balance and blood gases. There are more women than men. The short- and long-term mortality is high despite intensive care treatment. The majority of patients are treated with NIV. The length of stay on the ICU is shorter when NIV is used. The choice between NIV and invasive ventilation in these patients may be irrational. It is guided by current guidelines, but other non-patient-related factors seem to influence this decision. NIV seems to be preferable to invasive ventilation at admission, not only according to short-term benefits but also to long-term survival. Failure of NIV followed by invasive ventilation does not have a poorer prognosis than directly employing invasive ventilation. The health-related quality of life of COPD patients after treatment on Swedish ICUs is lower than in the general population. However it does not decline between 6 and 24 months after ICU discharge. After 24 months the HRQL is quite similar to that of COPD patients not treated on the ICU.Conclusions: COPD patients in need of ventilatory support admitted to Swedish ICUs are severely ill on admission, and their short- and long-term mortality is high despite ICU care and ventilatory treatment. Non-invasive ventilation should be the first line treatment on admission. NIV has short- and long-term benefits compared to invasive ventilation, without increasing mortality risk in case of failure. After discharge from the ICU and recovery, the HRQL of COPD patients is lower than in the general population, but comparable to COPD patients not treated on the ICU.
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| 4. |
- Samuelsson, Anders, 1960-
(author)
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Effects of burns and vasoactive drugs on human skin : Clinical and Experimental studies using microdialysis
- 2010
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Doctoral thesis (other academic/artistic)abstract
- Patients who require critical care, including those with burns, are affected by a systemic inflammatory reaction, which at times has consequences such as multiple organ dysfunction and failure. It has become increasingly evident that other factors important in the development of organ dysfunction are disturbances at the tissue level, in the microcirculation. Such disturbances activate cascade systems including stress hormones, all of which have local effects on organ function.Despite this knowledge, monitoring and treatment in critical illness today relies mainly on central haemodynamics and blood sampling.Microdialysis is a minimally invasive technique that enables us to study the chemical composition and changes in biochemistry in the extracellular, extravascular space in living tissues. Most of our current experience is from animal models, but the technique has also been used in humans and has become routine in many neurosurgical intensive care units to monitor brain biochemistry after severe injury. In skin, this experience is limited. During the first half of this thesis we studied the injured and uninjured skin of severely burned patients. The results show that there are severe local metabolic disturbances in both injured and uninjured skin. Most interesting is a sustained tissue acidosis, which is not detectable in systemic (blood) sampling. We also recorded considerable alterations in the glucose homeostasis locally in the skin, suggesting a cellular or mitochondrial dysfunction. In parallel, we noted increased tissue glycerol concentrations, which indicated appreciable traumainduced lipolysis.We also examined serotonin kinetics in the same group of patients, as serotonin has been claimed to be a key mediator of the vasoplegia and permeability disturbances found in patients with burns. We have shown, for the first time in humans to our knowledge, that concentrations of serotonin in skin are increased tenfold, whereas blood and urine concentrations are just above normal. The findings support the need for local monitoring of substances with rapid local reabsorption, or degradation, or both. The results also indicate that serotonin may be important for the systemic response that characterises burn injuries.In the second half of the thesis we evaluated the effects of microdosing in skin on metabolism and blood flow of vasoactive, mainly stress-response-related, drugs by the microdialysis system. The objectives were to isolate the local effects of the drugs to enable a better understanding of the complex relation between metabolic effects and effects induced by changes in local blood flow. In the first of these two studies we showed that by giving noradrenaline and nitroglycerine into the skin of healthy subjects we induced anticipated changes in skin metabolism and blood flow. The results suggest that the model may be used to examine vascular and metabolic effects induced locally by vasoactive compounds. Data from the last study indicate that conventional pharmacodynamic models (Emax) for time and dose response modelling may be successfully used to measure the vascular and metabolic response in this microdosing model.We conclude that the microdialysis technique can be successfully used to monitor skin metabolism and iso late a mediator (serotonin) of the local skin response in burned patients. It was also feasible to develop a vascular model in skin based on microdialysis to deliver vasoactive substances locally to the skin of healthy volunteers. This model provided a framework in which the metabolic effects of hypoperfusion and reperfusion in skin tissues could be examined further.
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| 5. |
- Steinvall, Ingrid
(author)
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Organ dysfunction among patients with major burns
- 2011
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Doctoral thesis (other academic/artistic)abstract
- The number of patients who are admitted for in-hospital care in Sweden because of burns is about 12/100,000, and only a small proportion of these have larger burns. Among them, and particularly among those who die in hospital, a condition referred to as “organ dysfunction” is common and an important factor in morbidity and mortality. The fact that the time of the initial event is known, and the magnitude of the insult is quantifiable, makes the burned patient ideal to be studied. In this doctoral thesis organ dysfunction and mortality were studied in a descriptive, prospective, exploratory study (no interventions or control groups) in patients admitted consecutively to a national burn centre in Sweden.The respiratory dysfunction that is seen after burns was found to be equally often the result of acute respiratory distress syndrome and inhalation injury. We found little support for the idea that this early dysfunction is caused by pneumonia, ventilator-induced lung injury, or sepsis. Acute kidney injury (AKI) was also common, and mortality was associated with severity. Importantly, renal dysfunction recovered among the patients who survived. Pulmonary dysfunction and systemic inflammatory response syndrome developed before the onset of AKI. Sepsis was a possible aggravating factor for AKI in 48% of 31 patients; but we could find no support for the idea that late AKI was mainly associated with sepsis. We found that older age (over 60 years), greater TBSA%, and respiratory dysfunction were associated with increased mortality, but there was no association between the overall mortality and sex. We also found that early transient liver dysfunction was common, and recorded early hepatic “hyper”- function among many young adults. Persistent low values indicating severe liver dysfunction were found among patients who eventually died.We conclude from this investigation that overall organ dysfunction is an early and common phenomenon among patients with severe burns. Our data suggest that the prognosis of organ dysfunction among these patients is good, and function recovers among most survivors. Multiple organ failure was, however, the main cause of death. The findings of the early onset in respiratory dysfunction and a delay in signs of sepsis are congruous with the gutlymphatic hypothesis for the development of organ dysfunction, and the idea of the lung as an inflammatory engine for its progression. We think that the early onset favours a syndrome in which organ dysfunction is induced by an inflammatory process mediated by the effect of the burn rather than being secondary to sepsis.Our data further suggest that clinical strategies to improve burn care further should be focused on early interventions, interesting examples of which include: selective decontamination of the gastrointestinal tract to prevent translocation of gut-derived toxic and inflammatory factors; optimisation of fluid replacement during the first 8 hours after injury by goal-directed resuscitation; and possible improvement in the fluid treatment given before admission.
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| 6. |
- Bäckman, Carl G
(author)
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The photo-diary and follow-up appointment on the ICU: Giving back the time to patients and relatives. : A descriptive and interventional study
- 2011
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Doctoral thesis (other academic/artistic)abstract
- Background: Patients on the ICU often spend a great deal of their time either unconscious or heavily sedated. When they return from the zone between life and death they are often in a state of confusion where dreams and delusions are intertwined with reality and it is not always easy to distinguish them apart. These experiences could lead to psychological problems and post-traumatic stress disorder (PTSD). Recovery may be improved by filling in the significant memory gaps and explaining what really happened during the “chaotic” time on the ICU. The provision of a diary describing the patients’ stay in ICU on a day to day basis and a follow-up meeting (together named the ICU-diary concept), may help the whole family to understand.Aim: The principal aim of this thesis was to see if the ICU-diary concept was of help to patients and relatives in the recovery after critical illness. A further aim was to look for precipitants in the ICU of PTSD.Material and Methods: ICU patients in a handful of European countries and their relatives have been studied. The studies have been single and multi-centred and we have used descriptive observational, randomised controlled and cohort study designs, including matched case-control designs. Quantitative methods have been used with questionnaires and structured interviews using established instruments (i.e Post-traumatic stress syndrome screening-14, Post-traumatic diagnostic scale, ICU memory tool, Short Form-36, Pearlin-Schooler Mastery Scale, Hopelessness scale) as the principal means of data collection.Results: The ICU-diary concept was seen to be a positive and useful aid in helping patients and their relatives understand the events that took place during the time on the ICU. It also decreased the risk for PTSD among patients and relatives. Patients that were supported with the ICU-diary concept perceived a better health-related quality of life even 3 years after the ICU stay. We did not find any definite improvement by the ICU-diary concept in mastery and hope. Variations in how the patients were cared for in the ICU had a significant effect on the development of PTSD. The implementation of an ICU diary, for instance, was associated with a lower frequency of PTSD.Conclusions: The ICU-diary concept was found helpful by patients and their relatives. It was associated with a reduction in new onset PTSD and improved health-related quality of life. The results are encouraging and suggest that an ICU diary may represent an important first step to help patients and relatives come to terms with their experiences during critical illness.ISBN 978-
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| 7. |
- Farnebo, Simon, 1972-
(author)
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On microvascular blood flow assessment with the new microdialysis urea clearance technique
- 2010
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Doctoral thesis (other academic/artistic)abstract
- The aim of this thesis was to develop and evaluate a new way of monitoring blood flow with microdialysis. A thin catheter consisting of a semipermeable membrane is implanted in the tissue being studied. The catheter is perfused by a solution that closely resembles interstitial fluid, and small water-soluble substances are allowed to diffuse passively through the pores of the membrane with the aim at reaching equilibrium with the surrounding tissue. The minimally invasive character of microdialysis, and its ability to sample from the organ being studied, make microdialysis attractive in most research settings as well as for clinical surveillance. It has, however, become increasingly evident that microdialysis under conditions of non-equilibrium - for example, fluctuating regional blood flow, will alter the results gained. We have therefore aimed to explore the possibilities of developing a new marker of blood flow that will yield information about changes in blood flow that occur in the area of the microdialysis catheter itself.We hypothesised that the changes in the diffusion of exogenous urea could be used as markers of changes in tissue blood flow. The theoretical basis for this approach is that the mass transfer of urea will increase across the dialysis membrane secondary to increased blood flow. As removal of urea from the vicinity of the dialysis membrane increases with increased blood flow, the concentration gradient of urea between the perfusate and tissue will also increase. This in turn will result in a greater loss of urea from the perfusate. The changes noted in retrieval of urea from dialysate by the system are therefore thought to be inversely related to changes in blood flow. We tested our hypothesis in two species of animal (rat and pig) and in man, and in three organ systems (muscle, liver, and skin), and present four papers that indicate that the urea clearance technique provides reliable and reproducible results. The technique was evaluated against conventional metabolic markers (lactate and glucose), the ethanol clearance technique (microdialysis), laser Doppler perfusion imaging (LDPI), and polarisation light spectroscopy (TiVi).We present evidence that the urea clearance technique can be used to assess blood flow in the organs studied reliably and reproducibly with microdialysis. The microdialysis technique is minimally invasive and safe for the recipient, and catheters can easily be implanted during operation to monitor organs at risk. Urea is easily analysed as a standard assay among other “basic” metabolic markers (in a standard microdialysis kit) and has favourable characteristics with a standardised measurement system that is routinely used for monitoring metabolites in the clinic. The technique is also effective when used at lower perfusate flow rates (<1 μl/minute), which is advantageous as the recovery of metabolic markers increases at low perfusate flow rates.
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