A Single-Lumen Central Venous Catheter for Continuous and Direct Intra-abdominal Pressure Measurement

Background: Abdominal compartment syndrome (ACS) is associated with high morbidity and mortality rates. Therefore, the need for a good diagnostic tool to predict intra-abdominal hypertension (IAH) and progression to ACS is paramount. Bladder pressure (BP) has been used for several years for intra-abdominal pressure (IAP) measurement but has the disadvantage that it is not a continuous measurement. In this study, a single-lumen central venous catheter (CVC) is placed through the abdominal wall into the abdominal cavity to continuously and directly monitor the intra-abdominal pressure (CDIAP). The aim of this study was to evaluate the use of CDIAP to measure BP as a representative of the true IAP. Methods: Both BP and CDIAP were prospectively recorded on a variety of surgical patients admitted to the intensive care unit (ICU) from March 2003 up to December 2004. At the end of the surgical procedure, the CVC was placed through the abdominal wall and connected to a pressure transducer. In addition, the BP was measured through the urine drainage port after clamping the catheter and filling the bladder with 50 ml of 0.9% saline. At least three paired measurements (BP and CDIAP) were performed for at least one day on the ICU in a standardized manner at preset time intervals on each patient. The paired measurements were compared using the Bland-Altman (B-A) method. Data are presented as mean ± standard deviation. Results: Over a period of 22 months (March 2003 until December 2004), 125 paired measurements of both BP and CDIAP were recorded on 25 patients. The mean age was 72.4 ± 6.6 years. Eighteen patients underwent central vascular surgery, and seven patients with peritonitis received laparotomy. The mean CDIAP was 11.4 ± 4.8 (range 2-30) mmHg, and the BP was 12.9 ± 5.3 (range 3-37) mmHg. The mean difference between CDIAP and BP was 1.6 ± 2.7 mmHg. There was an acceptable level of agreement (intraclass correlation 0.82) between IAP measured by BP and IAP measured via CDIAP. Conclusion: Continuous direct intra-abdominal pressure measurement proved that the BP measurement approach of Kron is representative of the IAP. CDIAP measurement is accurate and makes it easier for the nursing staff to be informed of the IAP

Central coordination as an alternative for local coordination in a multicenter randomized controlled trial: the FAITH trial experience

Contains fulltext : 110505.pdf (publisher's version ) (Open Access)BACKGROUND: Surgeons in the Netherlands, Canada and the US participate in the FAITH trial (Fixation using Alternative Implants for the Treatment of Hip fractures). Dutch sites are managed and visited by a financed central trial coordinator, whereas most Canadian and US sites have local study coordinators and receive per patient payment. This study was aimed to assess how these different trial management strategies affected trial performance. METHODS: Details related to obtaining ethics approval, time to trial start-up, inclusion, and percentage completed follow-ups were collected for each trial site and compared. Pre-trial screening data were compared with actual inclusion rates. RESULTS: Median trial start-up ranged from 41 days (P25-P75 10-139) in the Netherlands to 232 days (P25-P75 98-423) in Canada (p = 0.027). The inclusion rate was highest in the Netherlands; median 1.03 patients (P25-P75 0.43-2.21) per site per month, representing 34.4% of the total eligible population. It was lowest in Canada; 0.14 inclusions (P25-P75 0.00-0.28), representing 3.9% of eligible patients (p < 0.001). The percentage completed follow-ups was 83% for Canadian and Dutch sites and 70% for US sites (p = 0.217). CONCLUSIONS: In this trial, a central financed trial coordinator to manage all trial related tasks in participating sites resulted in better trial progression and a similar follow-up. It is therefore a suitable alternative for appointing these tasks to local research assistants. The central coordinator approach can enable smaller regional hospitals to participate in multicenter randomized controlled trials. Circumstances such as available budget, sample size, and geographical area should however be taken into account when choosing a management strategy. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00761813

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Prevalence of intra-abdominal hypertension and markers for associated complications among severe burn patients: a multicenter prospective cohort study (BURNIAH study)

Purpose Severely burned patients are at risk for intra-abdominal hypertension (IAH) and associated complications such as organ failure, abdominal compartment syndrome (ACS), and death. The aim of this study was to determine the prevalence of IAH among severely burned patients. The secondary aim was to determine the value of urinary intestinal fatty acid binding protein (I-FABP) as early marker for IAH-associated complications. Methods A prospective observational study was performed in two burn centers in the Netherlands. Fifty-eight patients with burn injuries >= 15% of total body surface area (TBSA) were included. Intra-abdominal pressure (IAP) and urinary I-FABP, measured every 6 h during 72 h. Prevalence of IAH, new organ failure and ACS, and the value of urinary intestinal fatty acid binding protein (I-FABP) as early marker for IAH-associated complications were determined. Results Thirty-one (53%) patients developed IAH, 17 (29%) patients developed new organ failure, but no patients developed ACS. Patients had burns of 29% (P-25-P-75 19-42%) TBSA. Ln-transformed levels of urinary I-FABP and IAP were inversely correlated with an estimate of - 0.06 (95% CI - 0.10 to - 0.02; p = 0.002). Maximal urinary I-FABP levels had a fair discriminatory ability for patients with IAH with an area under the ROC curve of 74% (p = 0.001). Urinary I-FABP levels had no predictive value for IAH or new organ failure in severe burn patients. Conclusions The prevalence of IAH among patients with >= 15% TBSA burned was 53%. None of the patients developed ACS. A relevant diagnostic or predictive value of I-FABP levels in identifying patients at risk for IAH-related complications, could not be demonstrated

En jämförelse mellan deep reinforcement learning och Q-tabeller i spelet backgammon

Reinforcement learning attempts to mimic how humans react to their surrounding environment by giving feedback to software agents based on the actions they take. To test the capabilities of these agents, researches have long regarded board games as a powerful tool. This thesis compares two approaches to reinforcement learning in the board game backgammon, a Q-table and a deep reinforcement network. It was determined which approach surpassed the other in terms of accuracy and convergence rate towards the perceived optimal strategy. The evaluation is performed by training the agents using the self-learning approach. After variable amounts of training sessions, the agents are benchmarked against each other and a third, random agent. The results derived from the study indicate that the convergence rate of the deep learning agent is far superior to that of the Q-table agent. However, the results also indicate that the accuracy of Q-tables is greater than that of deep learning once the former has mapped the environment

A self-medication hypothesis for increased vulnerability to drug abuse in prenatally restraint stressed rats

Stress-related events that occur in the perinatal period can permanently change brain and behavior of the developing individual and there is increasing evidence that early-life adversity is a contributing factor in the etiology of drug abuse and mood disorders. Neural adaptations resulting from early-life stress may mediate individual differences in novelty responsiveness and in turn contribute to drug abuse vulnerability. Prenatal restraint stress (PRS) in rats is a well-documented model of early stress known to induce long-lasting neurobiological and behavioral alterations including impaired feedback mechanisms of the HPA axis, enhanced novelty seeking, and increased sensitiveness to psychostimulants as well as anxiety/depression-like behavior. Together with the HPA axis, functional alterations of the mesolimbic dopamine system and of the metabotropic glutamate receptors system appear to be involved in the addiction-like profile of PRS rats