Assessment of the plasticizer exposure of hospital workers regularly handling medical devices: A pilot study.

Plastic medical devices, e.g. infusion sets, blood bags or tubing material, that are used manifold in the medical treatment of hospital patients, usually contain considerable amounts of plasticizers. Whereas several studies showed highly elevated inner plasticizer levels of patients treated with plasticized medical devices, little is known about the exposure situation of hospital staff. The present pilot study aimed to evaluate the urinary plasticizer metabolite levels of selected hospital workers of the blood bank (medical technical assistants, MTA) and of perfusionists that are regularly handling plasticized medical devices in order to estimate the work-related amount of the inner individual plasticizer exposure. The study subjects were asked to collect pre- and post-shift spot urine samples over the course of a working week, that were subsequently analyzed for selected urinary metabolites of the plasticizers DEHP, DINCH, DEHTP and TEHTM. Although the observed differences were rather low, a differentiated approach revealed a perceptible impact of the respective workplace environment on the individual urinary plasticizer metabolite levels. Thus, the group of blood bank MTA showed significantly elevated increment levels of urinary DEHP and DINCH metabolites, while the group of perfusionists, showed a considerable higher detection frequency of the main urinary TEHTM metabolite. All in all, however, it can be cautiously concluded by the results of the presented pilot study that a regular handling of plasticized medical devices by hospital employees (via inhalation or dermal contact) contributes demonstrably but yet only marginally to the individual internal plasticizer exposure.

Minimized Hemodiafiltration for Extracorporeal Membrane Oxygenation in Infants.

BACKGROUND: Fluid overload is a serious complication in the treatment of infants with extracorporeal membrane oxygenation (ECMO). Volume overload leads to prolonged ECMO therapy if left untreated. The renal replacement therapy of choice in pediatric patients is peritoneal dialysis or conventional dialysis using a "large" hemofiltration machine via a Shaldon catheter or directly connected to the ECMO system. This study describes the implementation of a novel minimized hemodiafiltration (HDF) system in pediatric patients on ECMO. METHODS: This retrospective analysis included 13 infants up to 5 kg who underwent 15 veno-arterial (V-A) ECMO runs with HDF. A minimized HDF system is integrated into an existing ECMO system (18-mL priming volume), connected post-oxygenation to the venous line, before the ECMO pump. Two infusion pumps are attached to the inlet and outlet of the hemofilter to control the HDF system.In addition to retention values (creatine and urea) at six defined time points, flow rates, dialysis parameters, and volume withdrawal were examined, as well as the number of HDF system changes. RESULTS: With a mean ECMO runtime of 156 hours, the HDF system was utilized for 131 hours. The mean blood flow through the hemofilter was 192 mL/min. The mean dialysate flow was 170 mL/h, with a mean volume deprivation of 39 mL/h. The HDF system was changed once in seven cases and twice in three cases. CONCLUSION: There were no complications with the minimized HDF system in all 15 applications. It allows safe patient volume management when treating infants with ECMO, with effective elimination of urinary substances.

Microplegia in paediatric hearts.

INTRODUCTION: A basic prerequisite for a good surgical outcome in heart surgery is optimal myocardial protection. However, cardioplegia strategies used in adult cardiac surgery are not directly transferable to infant hearts. Paediatric microplegia, analogous to Calafiore cardioplegia used in adult cardiac surgery, offers the advantage of safe myocardial protection without haemodilution. The use of concentration-dependent paediatric microplegia is new in clinical implementation. MATERIAL AND METHODS: Paediatric microplegia has been in clinical use in our institution since late 2014. It is applied via an 1/8 inch tube of a S5-HLM roller pump (LivaNova, Italy). As cardioplegic additive, a mixture of potassium (K) 20 mL (2 mmol/mL potassium chloride 14.9% Braun) and magnesium (Mg) 10 mL (4 mmol/mL Mg-sulphate Verla® i. v. 50%) is fixed into a syringe-pump (B. Braun, Germany). This additive is mixed with arterial patient blood from the oxygenator in different flowdependent ratios to form an effective cardioplegia. TECHNIQUE: After microplegia application of initially 25 mmol/L K with 11 mmol/L Mg for 2 min, a safe cardioplegic cardiac arrest is achieved, which after release of the coronary circulation, immediately returns to a spontaneous cardiac-rhythm. In the case of prolonged aortic clamping, microplegia is repeated every 20 min with a reduction of the application dose of K by 20% and Mg by 30% (20 mmol/L K; 8.5 mmol/L Mg) and a further reduction down to a maintenance dose (15 mmol/L K; 6 mmol/L Mg) after additional 20 min. SUMMARY: The microplegia adapted to the needs of paediatric myocardium is convincing due to its simple technical implementation for the perfusionist while avoiding haemodilution. However, the required intraoperative interval of microplegia of approx. 20 min demands adapted intraoperative management from the surgeon.

Transfontanellar Contrast-enhanced US for Intraoperative Imaging of Cerebral Perfusion during Neonatal Arterial Switch Operation.

Background Brain injury and subsequent neurodevelopmental disorders are major determinants for later-life outcomes in neonates with transposition of the great arteries (TGA). Purpose To quantitatively assess cerebral perfusion in neonates with TGA undergoing arterial switch operation (ASO) using transfontanellar contrast-enhanced US (T-CEUS). Materials and Methods In a prospective single-center cross-sectional diagnostic study, neonates with TGA scheduled for ASO were recruited from February 2018 to February 2020. Measurements were performed at five time points before, during, and after surgery (T1-T5), and 11 perfusion parameters were derived per cerebral hemisphere. Neonate clinical characteristics, heart rate, mean arterial pressure, central venous pressure, near-infrared spectroscopy, blood gas analyses, ventilation time, time spent in the pediatric intensive care unit, and time in hospital were correlated with imaging parameters. Analysis of variance or a mixed-effects model were used for groupwise comparisons. Results A total of 12 neonates (mean gestational age, 39 6/7 weeks ± 1/7 [SD]) were included and underwent ASO a mean of 6.9 days ± 3.4 after birth. When compared with baseline values, T-CEUS revealed a longer mean time-to-peak (right hemisphere, 4.3 seconds ± 2.1 vs 17 seconds ± 6.4 [P < .001]; left hemisphere, 4.0 seconds ± 2.3 vs 21 seconds ± 8.7 [P < .001]) and rise time (right hemisphere, 3.5 seconds ± 1.7 vs 11 seconds ± 5.1 [P = .002]; left hemisphere, 3.4 seconds ± 2.0 vs 22 seconds ± 7.8 [P = .004]) in both cerebral hemispheres during low-flow cardiopulmonary bypass and hypothermia (T4) for all neonates. Neonate age at surgery negatively correlated with T-CEUS parameters during ASO, as calculated with the area under the flow curve (AUC) during wash-in (R = -0.60, P = .020), washout (R = -0.82, P = .002), and both wash-in and washout (R = -0.79, P = .004). Mean AUC values were lower in neonates older than 7 days compared with younger neonates during wash-in ([87 arbitrary units {au} ± 77] × 102 vs [270 au ± 164] × 102, P = .049]), washout ([15 au ± 11] × 103 vs [65 au ± 38] × 103, P = .020]) and both wash-in and washout ([24 au ± 18] × 103 vs [92 au ± 53] × 103, P = .023). Conclusion Low-flow hypothermic conditions resulted in reduced cerebral perfusion, as measured with transfontanellar contrast-enhanced US, which inversely correlated with age at surgery. Clinical trial registration no. NCT03215628 © RSNA, 2022 Online supplemental material is available for this article.

Reduction of exposure to plasticizers in stored red blood cell units.

INTRODUCTION: Plastic can be toxic and hazardous to an organism's health, but it is being widely used in our daily lives. Di-2-ethylhexyl-phthalate is the most common plasticizer in medical devices made of polyvinylchloride and is commonly found in soft bags storing red blood cell units. Di-2-ethylhexyl-phthalate and its degradation product mono-2-ethylhexyl-phthalate can migrate into human body fluids, for example, blood and tissues. The aim of the study was to assess the concentration of plasticizers in red blood cell units according to storage time and after mechanical rinsing using a cell salvage device. METHODS: Levels of di-2-ethylhexyl-phthalate and mono-2-ethylhexyl-phthalate were analysed in 50 unwashed red blood cell units using liquid chromatography coupled with tandem mass spectrometry. In addition, phthalate concentrations were measured before and after mechanical rinsing in six more washed red blood cell units with storage times ranging between 36 and 56 days. A linear regression model was determined by the daily increase of di-2-ethylhexyl-phthalate and mono-2-ethylhexyl-phthalate in the stored red blood cell units subject to their storage time (range = 4-38 days), and the effect of mechanical rinsing on their phthalate concentration was calculated. RESULTS: A linear correlation was found between storage time of unwashed red blood cell units and the concentration of di-2-ethylhexyl-phthalate (p < 0.001) or mono-2-ethylhexyl-phthalate (p < 0.001). Stored red blood cell units older than 14 days had significantly higher concentrations of both contaminants than red blood cell units of shorter storage time (p < 0.001). Mechanical rinsing in washed red blood cell units attained a reduction in the di-2-ethylhexyl-phthalate and mono-2-ethylhexyl-phthalate concentration by a median of 53% (range = 18-68%; p = 0.031) and 87% (range = 68-96%; p = 0.031), respectively. CONCLUSION: Leaching of di-2-ethylhexyl-phthalate and mono-2-ethylhexyl-phthalate into red blood cell units depends on the duration of storage time. Plasticizers can be significantly reduced by mechanical rinsing using cell salvage devices, and thus, red blood cell units can be regenerated with respect to chemical contamination.

Multisite measurement of regional oxygen saturation in Fontan patients with and without protein-losing enteropathy at rest and during exercise.

BACKGROUND: Protein-losing enteropathy (PLE) is a severe complication of Fontan circulation with increased risk of end-organ dysfunction. We evaluated tissue oxygenation via near-infrared spectroscopy (NIRS) at different exercise levels in Fontan patients. METHODS: Assessment of multisite NIRS during cycle ergometer exercise and daily activities in three groups: Fontan patients with PLE; without PLE; patients with dextro-transposition of the great arteries (d-TGA); comparing univentricular with biventricular circulation and Fontan with/without PLE. Renal threshold analysis (<65%;<55%;<45%) of regional oxygen saturation (rSO2) was performed. RESULTS: Fontan patients showed reduced rSO2 (p < 0.05) in their quadriceps femoris muscle compared with biventricular d-TGA patients at all time points. rSO2 in renal tissue was reduced at baseline (p = 0.002), exercise (p = 0.0062), and daily activities (p = 0.03) in Fontan patients with PLE. Renal threshold analysis identified critically low renal rSO2 (rSO2 < 65%) in Fontan patients with PLE during exercise (95% of monitoring time below threshold) and daily activities (83.7% time below threshold). CONCLUSION: Fontan circulation is associated with decreased rSO2 values in skeletal muscle and hypoxemia of renal tissue solely in patients with PLE. Reduced rSO2 already during activities of daily life, might contribute to comorbidities in patients with Fontan circulation, including PLE and renal failure.

Ischaemia-related cell damage in extracorporeal preserved tissue - new findings with a novel perfusion model.

Tissue undergoing free transfer in transplant or reconstructive surgery always is at high risk of ischaemia-related cell damage. This study aims at assessing different procedures using an extracorporeal perfusion and oxygenation system to investigate the expression of hypoxia inducible factor (HIF)-1-α as marker for hypoxia and of the pro-apoptotic protein Caspase-3 in skeletal muscle to elucidate potential improvements in tissue conservation. Twenty-four porcine rectus abdominis muscles were assigned to five different groups and examined after they had been extracorporeally preserved for 60 min. time. Group I was left untreated (control), group II was perfused with a cardioplegic solution, group III was flushed with 10 ml of a cardioplegic solution and then left untreated. Group IV and V were perfused and oxygenated with either an isotone crystalloid solution or a cardioplegic solution. Among others, immunohistochemistry (Caspase-3 and HIF-1-α) of muscle samples was performed. Furthermore, oxygen partial pressure in the perfusate at the arterial and venous branch was measured. Expression of Caspase-3 after 60 min. was reduced in all groups compared to the control group. Furthermore, all groups (except group III) expressed less HIF-1-α than the control group. Oxygenation leads to higher oxygen levels at the venous branch compared to groups without oxygenation. Using an extracorporeal perfusion and oxygenation system cell damage could be reduced as indicated by stabilized expressions of Caspase-3 and HIF-1-α for 60 min. of tissue preservation. Complete depletion of oxygen at the venous branch can be prevented by oxygenation of the perfusate with ambient air.

One hundred ten days of extracorporeal membrane oxygenation in a young woman with postpartum cerebral venous thrombosis and acute respiratory distress syndrome.

Extracorporeal membrane oxygenation (ECMO) is often the last resort for serious acute respiratory distress syndrome (ARDS) when all non-invasive treatment options have failed to improve the patient's pulmonary condition. We present a successful long-term therapy with ECMO over 110 days in a 28-year-old woman. She developed postpartum cerebral venous thrombosis with severe respiratory insufficiency. Veno-venous ECMO rescued this young patient, allowing for full recovery.

Online oxygen measurements in ex vivo perfused muscle tissue in a porcine model using dynamic quenching methods.

INTRODUCTION: Transplantation of autologous free tissue flaps is the best applicable technique for treating large and complex tissue defects and still has one major failure criterion. Tissue--and in particular muscle tissue--is strongly sensitive to ischemia, thus after a critical period of oxygen depletion the risk of a partial or total flap loss is high. MATERIALS AND METHODS: For that reason a miniaturized ex vivo perfusion system has been developed, that supplies the tissue during operational delays. The purpose of this study was to determine the oxygenation levels during such a perfusion using different perfusates and therefore to objectify if a complementary oxygenation unit is required to improve perfusion quality. The oxygen levels of the tissue, as well of the perfusate, were measured by using minimal invasive optical oxygen sensors that are based on dynamic quenching. The ex vivo perfused tissue was the porcine rectus abdominis muscle. RESULTS: Results show, that during perfusion with heparinized crystalloid fluid (Jonosteril) and heparinized autologous whole blood, additional oxygenation of the perfusion reactor led to different ex vivo oxygen tissue saturations, which can be detected by dynamic quenching. CONCLUSION: Dynamic quenching methods are a promising and valuable technique to perform online oxygen measurements in ex vivo perfused muscle tissue in a porcine model.

Simultaneous and sensitive determination of the main metabolites of the plasticizer DEHP and its substitutes DEHTP, DINCH and TEHTM in human urine by coupling of on-line SPE, UHPLC and tandem mass spectrometry.

With the prominent but toxicologically critical plasticizer di-(2-ethylhexyl) phthalate (DEHP) declining, alternative plasticizers are increasingly used leading to a continuously more diverse exposure situation of humans with multiple plasticizers. Therefore, an on-line SPE-LC-MS/MS method for the simultaneous determination of the most relevant urinary biomarkers of exposure to DEHP and the alternative plasticizers 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH), di-(2-ethylhexyl) terephthalate (DEHTP) and tri-(2-ethylhexyl) trimellitate (TEHTM) was developed. The method is characterized by a high sensitivity with limits of detection ranging from 0.006 to 0.047 µg L-1 combined with an easy and straightforward sample preparation procedure. The wide linear working range of the method enables a reliable determination of analyte background levels in the general population as well as its potential use for monitoring studies investigating elevated plasticizer exposure settings. The method was successfully applied to urine samples from ten volunteers without occupational exposure to plasticizers revealing ubiquitous background exposure levels of the common plasticizers DEHP, DEHTP and DINCH.

Mobility and freedom of movement: A novel out-of-hospital treatment for pediatric patients with terminal cardiac insufficiency and a ventricular assist device.

Background: Due to rapid medical and technological progress, more and more pediatric patients with terminal cardiac insufficiency are being implanted with a ventricular assist device as a bridge to transplant without legal approval for hospital discharge. EXCOR® Active is a recently developed mobile driving unit for the EXCOR® ventricular assist device (EXCOR® VAD) with a long-lasting battery life that can manage small blood pumps, offering improved mobility for pediatric patients. This study strives to elaborate the requirements necessary for a safe home healthcare environment (HHE) for pediatric patients on EXCOR® VAD powered by the EXCOR® Active driving unit. Materials and methods: Patient- and device-related preconditions (medical, ethical, psychological, technical, structural, organizational) were analyzed with regard to feasibility and safety in three individual patient cases. Included were pediatric patients with terminal cardiac insufficiency in a stable medical condition receiving in-hospital treatment with a univentricular or biventricular EXCOR® VAD powered by EXCOR® Active. Analysis was single-center, data was obtained 05/2020-02/2022. Results: A total of three patients on EXCOR® VAD were identified for HHE treatment with the EXCOR® Active driving unit. Switch was performed safely and increased mobility led to improved psychomotor development and improved quality of life. No complications directly related to HHE-treatment occurred. One patient recently underwent an orthotopic heart transplant, one patient remains in HHE, and one patient died due to a complication not related to the HHE. Ethical approval for off-label use was obtained and patients and parents were given the required technical training and psychological support. Caregivers and medical professionals involved in the patients' care at home were briefed intensely. Remote consultations were implemented and interdisciplinary in-hospital checks reduced to a long-term 4-week-scheme. Conclusion: While it is challenging to discharge pediatric patients being treated with a paracorporeal ventricular assist device (EXCOR® VAD) from hospital, it is feasible and can be managed safely with the novel driving unit EXCOR® Active. A HHE may help to improve patients' psychomotor development, offer normalized social contacts and strengthen both patients' and parents' physical and mental resources. Legal approval and another study with a larger sample size are warranted.

Equal cerebral perfusion during extended aortic coarctation repair.

OBJECTIVES: Aortic coarctation with distal aortic arch hypoplasia can be effectively addressed by coarctation resection with extended end-to-end-anastomosis (REEEA). Particularly, when unilateral cerebral perfusion (UCP) is established by clamping of left-sided supra-aortic vessels, the extent of cerebral blood flow distribution during repair remains undetermined, so far. Transfontanellar contrast-enhanced ultrasound (T-CEUS) can be utilized for real-time visualization and quantitative evaluation of cerebral blood flow. This study quantitatively evaluates cerebral perfusion during REEEA by using intraoperative T-CEUS. METHODS: In a prospective study, 9 infants with open fontanelle undergoing REEEA [median age: 13 days (range 1-34) and median weight 3.1 kg (range 2.2-4.4)] were intraoperatively examined with T-CEUS at 3 consecutive time-points: before skin incision, during UCP and after skin suture. A software-based analysis of 11 parameters was used for data evaluation. Absolute and relative blood flow in contralateral hemispheres was measured in side-by-side comparison, and referenced to baseline measurements. RESULTS: No side-depend absolute or relative cerebral perfusion differences were found during REEEA, except for an increased relative 'wash-out-rate' (P = 0.0013) in favour of the right hemisphere after surgery. Compared to ipsilateral baseline levels, 'rise time' was transiently increased in right (P = 0.0277) and 'time-to-peak' in both hemispheres (right: P = 0.0403 and left: P = 0.0286), all during UCP. CONCLUSIONS: The use of T-CEUS provided evidence for homogenous distribution of contrast agent in both hemispheres during UCP. T-CEUS can be utilized for the postprocedural evaluation of cerebral perfusion during congenital cardiac surgery. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov Unique, Identifier: NCT03215628.

Extracorporeal perfusion of free muscle flaps in a porcine model using a miniaturized perfusion system.

INTRODUCTION: The development of techniques in transplantation medicine--including various aspects--has made extraordinary progress within the past three decades. However, the transplantation of free tissue flaps with the common problem of limited ischemia time frames remains an area in which the understanding of mechanism during ischemia and reperfusion is still limited. Thus, similar to other organ transplantations, the prolongation of ischemic time and the possibility to perform an ex vivo perfusion is desirable. The purpose of this study was to create a closed and steady ex vivo perfusion system in order to analyze the possibility of using a miniaturized perfusion system for free muscle flaps that could also be clinically used for other solid organ transplantation. MATERIALS AND METHODS: The rectus abdominis muscles of six german pigs were used in the study. Each of these free muscle flaps was perfused for a period of 2 h using a pulsatile and closed pump perfusion system by cannulating the arterial and venous vessels of the flap pedicle. During the ex vivo perfusion parameters such as arterial and venous pressures were measured continuously. RESULTS: A total of six ex vivo, closed and steady perfusions have been successfully performed. The optimal arterial flow rate of ex vivo perfusion of rectus abdominis muscle flaps was evaluated to be 10 ml/min. The constant measurement of arterial (46 ± 13 mmHg) and venous (-1 ± 1 mmHg) pressure in this ex vivo setting showed steady parameters during a period for up to 2 h. CONCLUSION: The data of this study indicate that the ex vivo perfusion of free muscle flaps is technically feasible and a closed and steady circulation is manageable for a period of up to 2 h.

Extracorporeal perfusion - reduced to a one-way infusion.

BACKGROUND: Extracorporeal perfusion (EP) is moving into focus of research in reconstructive and transplantation medicine for the preservation of amputates and free tissue transplants. The idea behind EP is the reduction of ischemia-related cell damage between separation from blood circulation and reanastomosis of the transplant. Most experimental approaches are based on a complex system that moves the perfusate in a circular course. OBJECTIVE AND METHODS: In this study, we aimed to evaluate if a simple perfusion by an infusion bag filled with an electrolyte solution can provide acceptable results in terms of flow stability, oxygen supply and viability conservation for EP of a muscle transplant. The results are compared to muscles perfused with a pump system as well as muscles stored under ischemic conditions after a one-time intravasal flushing with Jonosteril. RESULTS: With this simple method a sufficient oxygen supply could be achieved and functionality could be maintained between 3.35 times and 4.60 times longer compared to the control group. Annexin V positive nuclei, indicating apoptosis, increased by 9.7% in the perfused group compared to 24.4% in the control group. CONCLUSIONS: Overall, by decreasing the complexity of the system, EP by one-way infusion can become more feasible in clinical situations.

Plasticizer exposure of infants during cardiac surgery.

In the present study we investigated the internal exposure situation of infant patients to the plasticizers TEHTM (tri-2-ethylhexyl trimellitate) and DEHP (di-2-ethylhexyl phthalate). The study collective included 21 infant patients aged 2-22 months that had to undergo cardiac surgery using cardio pulmonary bypass (CPB). Each patient, but one, received blood products during surgery. A special feature was that the used CPB tubings were exclusively plasticized with the alternative plasticizer TEHTM and were free of the standard plasticizer DEHP, that raises increasing toxicological concern. The blood products were stored in DEHP plasticized blood bags. Blood and urine samples of each infant patient were analysed before and after the surgery for the levels of the plasticizers DEHP and TEHTM and their metabolites. In general, the plasticizers were detected in the post-surgery blood samples only, with TEHTM in low levels (median 18.4 µg/L) and DEHP in rather elevated levels (median 1046 µg/L). With respect to the urine samples, TEHTM metabolites were not detected in any of the samples. DEHP metabolites were found in all urine samples, however, in significantly increased median levels in the post-surgery urine samples of the infants (increase factor 5-26). Thus, the present study clearly demonstrates the strong contribution of standard medical procedures to the internal plasticizer burden of patients. Particularly with regard to the suspected endocrine disrupting activities of the phthalate plasticizer DEHP, the elevated internal levels of this plasticizer and its metabolites in infants following cardiac surgery are alarming.

How to Administer Near-Infrared Spectroscopy in Critically ill Neonates, Infants, and Children.

Near infrared spectroscopy (NIRS) calculates regional tissue oxygenation (rSO2) using the different absorption spectra of oxygenated and deoxygenated hemoglobin molecules. A probe placed on the skin emits light that is absorbed, scattered, and reflected by the underlying tissue. Detectors in the probe sense the amount of reflected light: this reflects the organ-specific ratio of oxygen supply and consumption - independent of pulsatile flow. Modern devices enable the simultaneous monitoring at different body sites. A rise or dip in the rSO2 curve visualizes changes in oxygen supply or demand before vital signs indicate them. The evolution of rSO2 values in relation to the starting point is more important for interpretation than are absolute values. A routine clinical application of NIRS is the surveillance of somatic and cerebral oxygenation during and after cardiac surgery. It is also administered in preterm infants at risk for necrotizing enterocolitis, newborns with hypoxic ischemic encephalopathy and a potential risk of impaired tissue oxygenation. In the future, NIRS could be increasingly used in multimodal neuromonitoring, or applied to monitor patients with other conditions (e.g., after resuscitation or traumatic brain injury).

Noninvasive control of adequate cerebral oxygenation during low-flow antegrade selective cerebral perfusion on adults and infants in the aortic arch surgery.

UNLABELLED: Real-time readings of the regional oxygen saturation (rSO(2)) using near-infrared spectroscopy (NIRS) during the aortic arch surgery can provide an early detection of perfusion or oxygenation abnormalities. BACKGROUND: Aortic arch repair techniques using low-flow antegrade selective cerebral perfusion have been standardized to a certain degree. However, some of the often-stated beneficial effects have never been proven. Especially, the existence of an adequate continuous flow in both cerebral hemispheres during the surgical procedure still remains unclear as the monitoring of an effective perfusion remains a nonstandardized technique. METHODS: Seventeen patients underwent surgical reconstruction of the aortic arch due to aortic aneurysm surgery (adult group n = 8 patients) or of the hypoplastic aortic arch due to hypoplastic left heart syndrome (HLHS) or aortic coarctation (infant group n = 9 patients) under general anesthesia and mild hypothermia (adult group 28 degrees C; infant group 25 degrees C). Mean weights were 92.75 +/- 14.00 kg and 4.29 +/- 1.32 kg, and mean ages were 58.25 +/- 10.19 years and 55.67 +/- 51.11 days in the adult group and the infant group, respectively. The cerebral O(2) saturation measurement was performed by continuous plotting of the somatic reflectance oximetry of the frontal regional tissue on both cerebral hemispheres (rSO(2), INVOS; Somanetics Corporation, Troy, MI, USA). RESULTS: During low-flow antegrade perfusion via innominate artery, continuous plots with similar values of O(2) saturation (rSO(2)) in both cerebral hemispheres were observed, whereas a decrease in the rSO(2) values below the desaturation threshold correlated with a displacement or an incorrect positioning of the arterial cannula in the right subclavian artery. CONCLUSIONS: Continuous monitorization of the cerebral O(2) saturation during aortic arch surgery in adults and infants is a feasible technique to control an adequate cannula positioning and to optimize clinical outcomes avoiding neurological complications related to cerebral malperfusion.

Effect of phospholipid coating on the migration of plasticizers from PVC tubes.

Plasticizers in polyvinyl chloride (PVC) are not covalently bound to the polymer and can thus migrate into the contact medium. The presented study investigated the potential effects of phospholipid-lining as anti-coagulation coating (ACC) on the migration rate of plasticizers from PVC tubing into blood. For the in-vitro study, five different groups of tubing sets in six replicates were perfused with sheep blood (Group A: PVC plasticized with di-(2-ethylhexyl) phthalate (DEHP) without ACC, Group B: DEHP-plasticized PVC with ACC, Group C: PVC plasticized with tri-(2-ethylhexyl) trimellitate (TOTM) without ACC, Group D: TOTM-plasticized PVC with ACC, Group E (control group): polyolefin material with ACC but without plasticizers). Both the levels of the unchanged plasticizers in blood and the concentration levels of their primary degradation products were assessed. For DEHP, the primary metabolite MEHP (mono-(2-ethylhexyl) phthalate) was determined. The isomers of MEHTM (mono-(2-ethylhexyl) trimellitate) and DEHTM (di-(2-ethylhexyl) trimellitate), respectively, were investigated as primary metabolites of TOTM. The calculated DEHP equivalents (sum of determined levels of DEHP and MEHP) after 24 h of perfusion displayed a tendency towards lower levels in the tubing sets without ACC (Group A (201 ±â€¯56.4 µmol/L)) compared to the tubing sets with ACC (Group B (253 ±â€¯369 µmol/L)). Significantly different DEHP equivalents between Group A and Group B were found after a perfusion time of 6 h and 10 h, respectively. A similar effect was observed for the TOTM-containing tubing sets. However, the absolute plasticizer migration rate of TOTM (TOTM equivalents) after 24 h of perfusion was found to be significantly lower compared to that of DEHP (with a factor of over 200). The results indicate that phospholipid coating (ACC) rather enhances the migration of plasticizers and of their primary degradation products from PVC tubing into streaming blood. The enhancement effect was found to be slightly greater for TOTM, but as TOTM migrates in significantly lower levels than DEHP in all experimental settings, TOTM is confirmed to be a recommendable alternative plasticizer to DEHP in medical devices.

Deep hypothermic circulatory arrest or tepid regional cerebral perfusion: impact on haemodynamics and myocardial integrity in a randomized experimental trial.

OBJECTIVES: Organ protective management during aortic arch surgery comprises deep hypothermic (18°C) circulatory arrest (DHCA), or moderate hypothermia (28°C/ 'tepid') with regional cerebral perfusion (TRCP). The aim of this experimental study was to evaluate the effect of distinct organ protective management on hemodynamic performance and myocardial integrity. METHODS: Ten male piglets were randomized to group DHCA (n = 5) or TRCP (n = 5) group and operated on cardiopulmonary bypass (CPB) with 60 min of aortic cross-clamping. Blood gas analysis was performed throughout the experiment. Haemodynamic assessment was performed using a thermodilution technique before and after CPB. Myocardial biopsies were taken 2 h after CPB and evaluated using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labelling assay and western blot analysis. RESULTS: At reperfusion, levels of central venous saturation were significantly higher (P = 0.016) and levels of lactate significantly lower (P = 0.029) in the DHCA group. After CPB, thermodilution measurements revealed higher stroke volume and lower peripheral resistance in the TRCP group (P = 0.012 and 0.037). At the end of the experiment, no significant differences regarding laboratory and haemodynamic parameters were evident. All specimens showed enrichment of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick-end labelling-positive cells exclusively at the left ventricular subendocardium with no difference between groups and equal concentrations of cyclo-oxygenase-2. CONCLUSIONS: TRCP is associated with decreased peripheral resistance and higher stroke volume immediately after CPB. However, this beneficial effect is contrasted by signs of lower body hypoperfusion, which is expressed by lower central venous saturations and higher lactate levels. Distinct strategies of organ protection did not seem to affect apoptotic/necrotic and inflammatory changes in the left ventricular myocardium.

Comparable Cerebral Blood Flow in Both Hemispheres During Regional Cerebral Perfusion in Infant Aortic Arch Surgery.

BACKGROUND: Cerebral protection during aortic arch repair can be provided by regional cerebral perfusion (RCP) through the innominate artery. This study addresses the question of an adequate bilateral blood flow in both hemispheres during RCP. METHODS: Fourteen infants (median age 11 days [range, 3 to 108]; median weight, 3.6 kg [range, 2.8 to 6.0 kg]) undergoing RCP (flow rate 54 to 60 mL · kg-1 · min-1) were prospectively included. Using combined transfontanellar/transtemporal two- and three-dimensional power/color Doppler sonography, cerebral blood flow intensity in the main cerebral vessels was displayed. Mean time average velocities were measured with combined pulse-wave Doppler in the basilar artery, and both sides of the internal carotid, anterior, and medial cerebral arteries. In addition, bifrontal regional cerebral oximetry (rSO2) was assessed. Comparing both hemispheres, measurements were performed at target temperature (28°C) during full-flow total body perfusion (TBP) and RCP. RESULTS: A regular circle of Willis with near-symmetric blood flow intensity to both hemispheres was visualized in all infants during both RCP and TBP. In the left internal carotid artery, blood flow direction was mixed (retrograde, n = 5; antegrade, n = 8) during TBP and retrograde during RCP. Comparison between sides showed comparable cerebral time average velocities and rSO2, except for higher time average velocities in the right internal carotid artery (TBP p = 0.019, RCP p = 0.09). Unilateral comparison between perfusion methods revealed significantly higher rSO2 in the right hemisphere during TBP (82% ± 9%) compared with RCP (74% ± 11%, p = 0.036). CONCLUSIONS: Bilateral assessment of cerebral rSO2 and time average velocity in the main great cerebral vessels suggests that RCP is associated with near-symmetric blood flow intensity to both hemispheres. Further neurodevelopmental studies are necessary to verify RCP for neuroprotection during aortic arch repair.