Increased splanchnic oxygen extraction because of routine nursing procedures

OBJECTIVE: Multiple organ failure is a common complication of acute circulatory and respiratory failure. We hypothesized that therapeutic interventions used routinely in intensive care can interfere with the perfusion of the gut and the liver, and thereby increase the risk of mismatch between oxygen supply and demand. DESIGN: Prospective, observational study. SETTING: Interdisciplinary intensive care unit (ICU) of a university hospital. PATIENTS: Thirty-six patients on mechanical ventilation with acute respiratory or circulatory failure or severe infection were included. INTERVENTIONS: Insertion of a hepatic venous catheter. MEASUREMENTS AND MAIN RESULTS: Daily nursing procedures were recorded. A decrease of >or=5% in hepatic venous oxygen saturation (Sho2) was considered relevant. Observation time was 64 (29-104) hours (median [interquartile range]). The ICU stay was 11 (8-15) days, and hospital mortality was 35%. The number of periods with procedures/patient was 170 (98-268), the number of procedure-related decreases in Sho2 was 29 (13-41), and the number of decreases in Sho2 unrelated to procedures was 9 (4-19). Accordingly, procedure-related Sho2 decreases occurred 11 (7-17) times per day. Median Sho2 decrease during the procedures was 7 (5-10)%, and median increase in the gradient between mixed and hepatic venous oxygen saturation was 6 (4-9)%. Procedures that caused most Sho2 decreases were airway suctioning, assessment of level of sedation, and changing patients' position. Sho2 decreases were associated with small but significant increases in heart rate and intravascular pressures. Maximal Sequential Organ Failure Assessment scores in the ICU correlated with the number of Sho2 decreases (r: .56; p < 0.001) and with the number of procedure-related Sho2 decreases (r: .60; p < 0.001). CONCLUSIONS: Patients are exposed to repeated episodes of impaired splanchnic perfusion during routine nursing procedures. More research is needed to examine the correlation, if any, between nursing procedures and hepatic venous desaturation.

RFID Transponders : Link between information and material flows. How reliable are identification procedures?

Along with the growing complexity of logistic chains the demand for transparency of informations has increased. The use of intelligent RFID-Technology offers the possibility to optimize and control all capacities in use, since it enables the identification and tracking of goods alongside the entire supply chain. Every single product can be located at any given time and a multitude of current and historical data can be transferred. The interaction of the flow of material and the flow of information between the various process steps can be optimized by using RFID-Technology since it guarantees that all required data is available at the right time and at the right place. The local accessibility and convertibility of data allows a flexible, decentralised control of logistic systems. As additional advantages of RFID-Components can be considered that they are individually writable and that their identification can be achieved over considerable distances even if there is no intervisibility between tag and reader. The use of RFID-Transponder opens up new potentials regarding process security, reduction of logistic costs or availability of products. These advantages depend on reliability of the identification processes. The undisputed potentials that are made accessible by the use of RFID-Elements can only be beneficial when the informations that are decentralised and attached to goods and loading equipment can be reliably retrieved at the required points. The communication between tag and reader can be influenced by different materials such as metal, that can disturbed or complicate the radio contact. The communications reliability is subject of various tests and experiments that analyse the effects of different filling materials as well as different alignments of tags on the loading equipment.

Effects of Gender on the Incidence of Cardiac Tamponade Following Catheter Ablation of Atrial Fibrillation: Results from a Worldwide Survey in 34,943 AF Ablation Procedures.

BACKGROUND -Cardiac tamponade is the most dramatic complication observed during atrial fibrillation (AF) ablation and the leading cause of procedure-related mortality. Female gender is a known risk factor for complications during AF ablation; however, it is unknown whether women have a higher risk of tamponade. METHODS AND RESULTS -A systematic Medline search was used to locate academic electrophysiologic (EP) centers that reported cases of tamponade occurring during AF ablation. Centers were asked to provide information on cases of acute tamponade according to gender and their mode of management including any case of related mortality. Nineteen EP centers provided information on 34,943 ablation procedures involving 25,261 (72%) males. Overall 289 (0.9%) cases of tamponade were reported: 120 (1.24%) in females and 169 (0.67%) in males (odds ratio 1.83, P<0.001). There was a reciprocal association between center volume and the occurrence of tamponade with substantial lower risk in high volume centers. Most cases of tamponade occurred during catheter manipulation or ablation; females tended to develop more tamponades during transseptal catheterization. No gender difference in the mode of management was observed. However, 16% cases of tamponade required surgery with lower rates in high volume centers. Three cases of tamponade (1%) culminated in death. CONCLUSIONS -Tamponade during AF ablation procedures is relatively rare. Women have an almost twofold higher risk for developing this complication. The risk of tamponade among women decreases substantially in high volume centers. Surgical back-up and acute management skills for treating tamponade are important in centers performing AF ablation.

Evaluation of the Hepa Wash® treatment in pigs with acute liver failure

BACKGROUND Mortality of patients with acute liver failure (ALF) is still unacceptably high. Available liver support systems are still of limited success at improving survival. A new type of albumin dialysis, the Hepa Wash® system, was newly introduced. We evaluated the new liver support system as well as the Molecular Adsorbent Recycling System (MARS) in an ischemic porcine model of ALF. METHODS In the first study animals were randomly allocated to control (n=5) and Hepa Wash (n=6) groups. In a further pilot study, two animals were treated with the MARS-system. All animals received the same medical and surgical procedures. An intraparenchymal intracranial pressure was inserted. Hemodynamic monitoring and goal-directed fluid therapy using the PiCCO system was done. Animals underwent functional end-to-side portacaval shunt and ligation of hepatic arteries. Treatment with albumin dialysis was started after fall of cerebral perfusion pressure to 45 mmHg and continued for 8 h. RESULTS All animals in the Hepa Wash group survived the 13-hour observation period, except for one that died after stopping treatment. Four of the control animals died within this period (p=0.03). Hepa Wash significantly reduced impairment of cerebral perfusion pressure (23±2 vs. 10±3 mmHg, p=0.006) and mean arterial pressure (37±1 vs. 24±2 mmHg, p=0.006) but had no effect on intracranial pressure (14±1 vs. 15±1 mmHg, p=0.72). Hepa Wash also enhanced cardiac index (4.94±0.32 vs. 3.36±0.25 l/min/m2, p=0.006) and renal function (urine production, 1850 ± 570 vs. 420 ± 180 ml, p=0.045) and eliminated water soluble (creatinine, 1.3±0.2 vs. 3.2±0.3 mg/dl, p=0.01; ammonia 562±124 vs. 1382±92 μg/dl, p=0.006) and protein-bound toxins (nitrate/nitrite 5.54±1.57 vs. 49.82±13.27 μmol/l, p=0.01). No adverse events that could be attributed to the Hepa Wash treatment were observed. CONCLUSIONS Hepa Wash was a safe procedure and improved multiorgan system failure in pigs with ALF. The survival benefit could be the result of ameliorating different organ functions in association with the detoxification capacity of water soluble and protein-bound toxins.

3D Face Reconstruction from 2D Pictures: First Results of a Web-Based Computer Aided System for Aesthetic Procedures

The human face is a vital component of our identity and many people undergo medical aesthetics procedures in order to achieve an ideal or desired look. However, communication between physician and patient is fundamental to understand the patient’s wishes and to achieve the desired results. To date, most plastic surgeons rely on either “free hand” 2D drawings on picture printouts or computerized picture morphing. Alternatively, hardware dependent solutions allow facial shapes to be created and planned in 3D, but they are usually expensive or complex to handle. To offer a simple and hardware independent solution, we propose a web-based application that uses 3 standard 2D pictures to create a 3D representation of the patient’s face on which facial aesthetic procedures such as filling, skin clearing or rejuvenation, and rhinoplasty are planned in 3D. The proposed application couples a set of well-established methods together in a novel manner to optimize 3D reconstructions for clinical use. Face reconstructions performed with the application were evaluated by two plastic surgeons and also compared to ground truth data. Results showed the application can provide accurate 3D face representations to be used in clinics (within an average of 2 mm error) in less than 5 min.

Are Today’s Medical School Graduates Performing the Same Number of Medical Procedures Compared to Graduates Ten Years Ago? A case for Simulation?

INTRODUCTION: Medical schools are charged with providing both a strong basic science and clinical curriculum for their students. In most institutions instruction in performing the core clinical procedures is part of the curriculum, but because of many constraints do medical students practice these procedures as many times as medical students in the past? Several studies have concluded that medical students today feel incompetent to perform basic clinical procedures at the time of graduation. [See PDF for complete abstract]

Implementation of an Anthropomorphic Phantom for the Evaluation of Proton Therapy Treatment Procedures

With an increasing number of institutions offering proton therapy, the number of multi-institutional clinical trials involving proton therapy will also increase in the coming years. The Radiological Physics Center monitors sites involved in clinical trials through the use of site visits and remote auditing with thermoluminescent dosimeters (TLD) and mailable anthropomorphic phantoms. Currently, there are no heterogeneous phantoms that have been commissioned to evaluate proton therapy. It was hypothesized that an anthropomorphic pelvis phantom can be designed to audit treatment procedures (patient simulation, treatment planning and treatment delivery) at proton facilities to confirm agreement between the measured dose and calculated dose within 5%/3mm with a reproducibility of 3%. A pelvis phantom originally designed for use with photon treatments was retrofitted for use in proton therapy. The relative stopping power (SP) of each phantom material was measured. Hounsfield Units (HU) for each phantom material were measured with a CT scanner and compared to the relative stopping power calibration curve. The tissue equivalency for each material was calculated. Two proton treatment plans were created; one which did not correct for material SP differences (Plan 1) and one plan which did correct for SP differences (Plan 2). Film and TLD were loaded into the phantom and the phantom was irradiated 3 times per plan. The measured values were compared to the HU-SP calibration curve and it was found that the stopping powers for the materials could be underestimated by 5-10%. Plan 1 passed the criteria for the TLD and film margins with reproducibility under 3% between the 3 trials. Plan 2 failed because the right-left film dose profile average displacement was -9.0 mm on the left side and 6.0 mm on the right side. Plan 2 was intended to improve the agreements and instead introduced large displacements along the path of the beam. Plan 2 more closely represented the actual phantom composition with corrected stopping powers and should have shown an agreement between the measured and calculated dose within 5%/3mm. The hypothesis was rejected and the pelvis phantom was found to be not suitable to evaluate proton therapy treatment procedures.

MODIFICATION AND IMPLEMENTATION OF THE RPC HETEROGENEOUS THORAX PHANTOM FOR VERIFICATION OF PROTON THERAPY TREATMENT PROCEDURES

The Radiological Physics Center (RPC) provides heterogeneous phantoms that are used to evaluate radiation treatment procedures as part of a comprehensive quality assurance program for institutions participating in clinical trials. It was hypothesized that the existing RPC heterogeneous thorax phantom can be modified to assess lung tumor proton beam therapy procedures involving patient simulation, treatment planning, and treatment delivery, and could confirm agreement between the measured dose and calculated dose within 5%/3mm with a reproducibility of 5%. The Hounsfield Units (HU) for lung equivalent materials (balsa wood and cork) was measured using a CT scanner. The relative linear stopping power (RLSP) of these materials was measured. The linear energy transfer (LET) of Gafchromic EBT2 film was analyzed utilizing parallel and perpendicular orientations in a water tank and compared to ion chamber readings. Both parallel and perpendicular orientations displayed a quenching effect underperforming the ion chamber, with the parallel orientation showing an average 31 % difference and the perpendicular showing an average of 15% difference. Two treatment plans were created that delivered the prescribed dose to the target volume, while achieving low entrance doses. Both treatment plans were designed using smeared compensators and expanded apertures, as would be utilized for a patient in the clinic. Plan 1a contained two beams that were set to orthogonal angles and a zero degree couch kick. Plan 1b utilized two beams set to 10 and 80 degrees with a 15 degree couch kick. EBT2 film and TLD were inserted and the phantom was irradiated 3 times for each plan. Both plans passed the criteria for the TLD measurements where the TLD values were within 7% of the dose calculated by Eclipse. Utilizing the 5%/3mm criteria, the 3 trial average of overall pass rate was 71% for Plan 1a. The 3 trial average for the overall pass rate was 76% for Plan 1b. The trials were then analyzed using RPC conventional lung treatment guidelines set forth by the RTOG: 5%/5mm, and an overall pass rate of 85%. Utilizing these criteria, only Plan 1b passed for all 3 trials, with an average overall pass rate of 89%.

The Development and Implementation of an Anthropomorphic Head Phantom for the Assessment of Proton Therapy Treatment Procedures

Proton therapy has become an increasingly more common method of radiation therapy, with the dose sparing to distal tissue making it an appealing option, particularly for treatment of brain tumors. This study sought to develop a head phantom for the Radiological Physics Center (RPC), the first to be used for credentialing of institutions wishing to participate in clinical trials involving brain tumor treatment of proton therapy. It was hypothesized that a head phantom could be created for the evaluation of proton therapy treatment procedures (treatment simulation, planning, and delivery) to assure agreement between the measured dose and calculated dose within ±5%/3mm with a reproducibility of ±3%. The relative stopping power (RSP) and Hounsfield Units (HU) were measured for potential phantom materials and a human skull was cast in tissue-equivalent Alderson material (RLSP 1.00, HU 16) with anatomical airways and a cylindrical hole for imaging and dosimetry inserts drilled into the phantom material. Two treatment plans, proton passive scattering and proton spot scanning, were created. Thermoluminescent dosimeters (TLDs) and film were loaded into the phantom dosimetry insert. Each treatment plan was delivered three separate times. Each treatment plan passed our 5%/3mm criteria, with a reproducibility of ±3%. The hypothesis was accepted and the phantom was found to be suitable for remote audits of proton therapy treatment facilities.