Comparison of the resonance sonorheometry based Quantra® system with rotational thromboelastometry ROTEM® sigma in cardiac surgery - a prospective observational study.

BACKGROUND: Measures of the sonorheometry based Quantra® viscoelastic hemostatic analyzer (HemoSonics, LCC, Charlottesville, VA, USA) were compared with corresponding results of the ROTEM® sigma device (Instrumentation Laboratory, Bedford, MA, USA). METHODS: In thirty-eight patients scheduled for elective cardiac surgery between December 2018 and October 2019, blood samples were taken after induction of anesthesia (sample 1) and after heparin neutralization (sample 2) and measured on Quantra (QPlus® Cartridge) and ROTEM sigma (ROTEM® sigma complete + hep Cartridge). Clot times and clot stiffness values were recorded. Clot stiffness values of ROTEM amplitudes (A in mm) were converted to shear modulus (G) in hectoPascal (hPa): G (hPa) = (5 x A)/(100-A). Additionally, time-to-results was recorded. Spearman rank test correlation and Bland Altman analysis were performed. RESULTS: Clot stiffness parameters of the Quantra correlated strongly with corresponding measurements of the ROTEM with r = 0.93 and 0.94 for EXTEM A10 vs CS and r = 0.94 and 0.96 for FIBTEM A10 vs FCS for sample 1 and 2, respectively. Quantra clot time correlated strongly with ROTEM INTEM CT with r = 0.71 for sample 1 and r = 0.75 for sample 2. However, Bland Altman analysis showed no agreement in all compared assays of both methods. The median time to delivery of first and complete results was significantly shorter for Quantra (412 and 658 s) compared to ROTEM sigma (839 and 1290 s). CONCLUSIONS: The Quantra showed a strong correlation with the ROTEM sigma for determining clot times and clot stiffness and the parameters assess similar aspects of clot development. However, these parameters are not directly interchangeable and implicate that separate cut-off values need to be established for users of the Quantra device. Word count: 278. TRIAL REGISTRATION: The study was retrospectively registered with ClinicalTrials.gov (ID: NCT04210830 ) at December 20th 2019.

Treatment of Seizures in Children and Adults in the Emergency Medical System of the City of Zurich, Switzerland - Midazolam vs. Diazepam - A Retrospective Analysis.

INTRODUCTION: Seizures count to critical situations emergency medical systems (EMS) are confronted with. OBJECTIVES: Evaluation of a modified treatment algorithm (MTAS-EMS) using diazepam and midazolam due to a supply bottleneck of iv lorazepam in 2012. METHODS: Retrospective study where data from patients treated for seizures by the EMS of the city of Zurich were analyzed. Effectiveness of the MTAS-EMS and i.v. diazepam in children and adults was compared with respect of cessation of seizure without recurrence over the period until arrival at the hospital. The chi-square and Fisher's exact test were used to compare categorical data. The Student's t-test and Mann Whitney test were used to compare numerical data. p-values < 0.05 are considered significant. RESULTS: Of 584 documented missions, 165 treated patients (126 adults and 39 children) were included. 115 patients (80 adults and 35 children) were treated according the MTAS-EMS. Cessation of seizure was achieved in 85% of the adults and in 97% of the children, if all options of the MTAS-EMS were used. The first dose of nasal midazolam was more successful in children compared to adults (p = 0.012). In adults, the single dose of i.v. diazepam terminated the seizure in 98% (p = 0.001) compared to 57% for the single dose of iv and 64% for nasal midazolam. CONCLUSIONS: The treatment success of the MTAS-EMS is high. However, in adults the single dose of i.v. diazepam is as successful as the completely used MTAS-EMS and seems to be superior to the single dose iv and nasal midazolam.

Short term general anesthesia for retro-bulbar block in ophthalmic surgery generates no significant hypercapnia.

To assess the impact of short time hypnosis for retro-bulbar anesthesia on ventilation in patients undergoing ophthalmic surgery of the anterior eye chamber. In all patients, a combined continuous transcutaneous carbon dioxide tension (PtcCO2) and partial oxygen saturation (SpO2) measurement was applied in addition to routine monitoring. To enable unconscious application of retro-bulbar anesthesia, intravenous thiopental was given in one to multiple bolus doses. Transient breathing support included chin lift, Esmarch maneuver and manual hand-bag ventilation via face mask. Main endpoints were apnea time, recovery time according to the Richmond Agitation Sedation Scale, as well as SpO2 and PtcCO2 readings at predefined time points. Fifty-two patients with a mean age of 68 ± 13 years were included. Average thiopental dose was 2.7 ± 0.6 mg/kg. In seven (13.5%) patients repeated doses of thiopental were necessary to a total of 3.3 ± 1.1 mg/kg. Except one patient, no severe, significant or clinical relevant hypercapnia or desaturation periods were observed, and the occurring elevation of PtcCO2 values did not correlate with the application of repeated doses of thiopental or the need for the Esmarch maneuver. Higher PtcCO2 values were associated with the presence of hypertension and smoking. Apnea (p < 0.001) and recovery (p = 0.003) time were significantly prolonged in the patients needing the Esmarch maneuver. Short term anesthesia with thiopental in ophthalmic surgery is associated with a mild but not clinically relevant hypercapnia.

Impact of city police layperson education and equipment with automatic external defibrillators on patient outcome after out of hospital cardiac arrest.

INTRODUCTION: Out of hospital cardiac arrest (OHCA) occurs frequently and the outcome is often dismal. Early defibrillation saves lives and brain function in OHCA. The Zurich city police (STAPO) forces were instructed and equipped to provide basic life support (BLS) and to use an AED in 2009. METHODS: Retrospective observational study comparing period 1 (P1) 2004-2009 before equipping and training of the STAPO and period 2 (P2) 2010-2015 after the implementation. Patients suffering from OHCA of cardiac or presumed cardiac origin in the city of Zurich undergoing CPR by EMS in P1 (n=709) and P2 (n=684) were included. Intervention periods and outcome were compared between the periods. Outcome variables were adjusted for patient age and gender, witnessed status, and defibrillation by the EMS, STAPO, layperson or no defibrillation. RESULTS: In P2, CPR was started by the STAPO in a median of 8 (IQR 6-9) minutes after the arrest and thus significantly earlier (median 3min) than by the EMS (p<0.001). STAPO performed the first defibrillation in a median of 9 (IQR 8-10) minutes and thus significantly earlier (median 6min) than the EMS (p<0.001). Outcome improved significantly in P2: proportion of patients with return of spontaneous circulation (ROSC, P2 35.8%, P1 24.0%, OR 1.8, 95% CI 1.4-2.2, p<0.001), hospital admission (P2 32.2%, P1 21.4%, OR 1.7, 95% CI 1.4-2.2, p<0.001) and survival to hospital discharge (P2 13.6%, P1 6.9%, OR 2.1 95% CI 1.5-3.0, p<0.001). If the patient was firstly defibrillated by the STAPO, ROSC (STAPO 74.4%, adj. OR 2.6, 95% CI 1.3-5.4, p=0.010) and hospital admission (STAPO 72.1%, adj. OR 2.8, 95% CI 1.4-5.6, p=0.005) was higher compared to patients firstly defibrillated by the EMS. Survival to hospital discharge (STAPO 30.2%, adj. OR 1.4, 95% CI 0.7-2.9, p=0.38) was unchanged. CONCLUSION: Dispatching BLS trained and AED equipped police forces results in earlier and more successful resuscitation of OHCA victims, leading to higher proportions of patients with ROSC, hospital admission and survival to hospital discharge.

Accuracy of non-invasive continuous total hemoglobin measurement by Pulse CO-Oximetry in severe traumatized and surgical bleeding patients.

The Masimo Radical-7 Pulse CO-Oximeter (Masimo Corp., USA) non-invasively computes hemoglobin concentration (SpHb). SpHb was compared to Co-Oximeter readings (CoOxHb) of arterial samples in surgery patients of the emergency department. Forty-six patients were enrolled. The Masimo R1 25L (revision F and G) adult adhesive sensor was attached to the ring finger of the arterially cannulated hand. Before start, every 30 min during surgery and in the case of severe bleeding SpHb and CoOxHb values were documented. SpHb and post hoc adjusted SpHb (AdSpHb) values were analyzed. Linear regression analysis and Bland-Altman plot for agreement were performed. The detection failure rate of SpHb was 24.5 %. CoOxHb and SpHb showed a strong correlation (r = +0.81), but agreement was moderate [bias (LOA) of -0.6 (-3.0; +1.9)] g/dl. Positive and negative predicted value was 0.49 and 0.69. Exclusion of changes of CoOxHb values ≤1 g/dl resulted in a positive and negative predictive value of 0.66 and 1.00. Post hoc adjustment of the SpHb (AdSpHb) improved linear correlation of CoOxHb and AdSpHb [r = +0.90 (p < 0.001)] but less the agreement [bias (LOA) of CoOxHb and AdSpHb = -0.1 (-2.1/+1.9) g/dl]. SpHb agreed only moderately with CoOxHb values and predicted decreases of CoOxHb only if changes of SpHb ≤ 1.0 g/dl were excluded. The detection failure rate of SpHb was high. At present, additional refinements of the current technology are necessary to further improve performance of non-invasive hemoglobin measurement in the clinical setting.

Transcutaneous continuous carbon dioxide tension monitoring reduced incidence, degree and duration of hypercapnia during combined regional anaesthesia and monitored anaesthesia care in shoulder surgery patients.

We studied the impact of transcutaneous continuous carbon dioxide tension (PtcCO2) monitoring on ventilation and oxygenation during monitored anaesthesia care (MAC) in patients scheduled for shoulder surgery with continuous interscalene block. 50 patients were randomised either to the intervention (I-group) or the control (C-group) group. In both groups MAC was performed using target controlled infusion of propofol and remifentanil. MAC regimen was adapted to PtcCO2 values in the I-group, whereas the C-group was blinded for these values. Primary outcome was the incidence, degree and duration of hypoventilation stages. In the I-group and the C-group the mean ± SD [range] of PtcCO2 and PaCO2 was 5.79 ± 0.84 [4.37] and 5.44 ± 0.59 [2.78] kPa, as well as 6.41 ± 1.17 [6.29] and 6.01 ± 0.96 [7.15] kPa. Periods of PtcCO2/PaCO2 > 6.5 kPa were 21.0 ± 35.7/1.2 ± 4.2 min in the I-group and 45.6 ± 40.0/18.6 ± 26.8 min in the C-group. Severe hypercapnia (PtcCO2 and/or PaCO2 > 7.5 kPa) was dected in 3/0 patients of the I-group and in 10/3 patients of the C-group. PtcCO2 and PaCO2 showed a strong correlation (r = 0.78), but only moderate agreement with a mean bias (LOA) of -0.37 (-1.69; +0.95) kPa showing an overestimation of the PaCO2. Sensitivity and specificity of PtcCO2 to detect changes of PaCO2 was 0.94 and 0.56, respectively. In no patient SpO2 or SaO2 values lower than 90% were measured. Despite a moderate agreement between PaCO2 and PtcCO2 the PtcCO2 monitoring significantly reduced incidence, degree and duration of hypercapnia in shoulder surgery patients with MAC.

Changes in coagulation in standard laboratory tests and ROTEM in trauma patients between on-scene and arrival in the emergency department.

BACKGROUND: When trauma patients arrive in the emergency department (ED), coagulopathy frequently is present. The time course, however, in which this coagulopathy develops is poorly understood. No study has fully evaluated the coagulation status, including thromboelastometry on-scene and at hospital arrival. We hypothesized that measured coagulation variables might change when measured at the scene of injury and upon arrival to the ED. METHODS: We performed a prospective, single-center, observational study investigating coagulation status in 50 trauma patients on-scene and at arrival in the ED. Measurements included arterial blood gases, ROTEM®, protein S100, protein C activity, protein S, Quick value, international normalized ratio, activated partial thromboplastin time, D-dimer, coagulation factor V (FV), coagulation factor XIII (FXIII), fibrinogen, hemoglobin, hematocrit, platelets, and volume and blood products being administered during the first 24 hours. RESULTS: Significant changes between on-scene and the ED were observed for the following values: partial venous oxygen pressure increased and sodium, glucose, and lactate decreased. For EXTEM, INTEM, and APTEM, clotting time and clot formation time increased significantly, whereas maximal clot firmness and angle α decreased significantly (all P ≤ 0.004). For FIBTEM, clotting time increased significantly and maximal clot firmness decreased significantly. In the laboratory, significant reductions in hemoglobin, hematocrit, platelets, activated partial thromboplastin time, fibrinogen, FV, FXIII, protein C activity, protein S, and protein S100 were observed (all P ≤ 0.001). CONCLUSIONS: Although most all laboratory and rotational thromboelastometry coagulation tests worsened over time when measured on-scene and in the ED, monitoring coagulation at the scene of trauma does not provide clinically important information in a majority of trauma patients. One hour after injury, significant activation and consumption of fibrinogen, FV, FXIII, protein C activity, and protein S were observed.

The influence of laboratory coagulation tests and clotting factor levels on Rotation Thromboelastometry (ROTEM(R)) during major surgery with hemorrhage.

BACKGROUND: The aim of this study was to determine the association between standard laboratory tests, coagulation factor concentrations, and Rotation Thromboelastometry (ROTEM® delta, TEM® International GmbH, Munich, Germany) in patients undergoing major surgery with hemorrhage. METHODS: In 45 patient's fibrinogen, factor VIII, factor XIII, International Normalized Ratio (INR), activated partial thromboplastin time (aPTT), thrombin time, hemoglobin, leukocytes, and platelet count were simultaneously measured intraoperatively with ROTEM (EXTEM, INTEM, FIBTEM, APTEM) measurements. ROTEM parameters were: clotting time (CT), clot formation time (CFT), maximum clot firmness (MCF), and α-angle. Demographic and laboratory data were expressed as mean ± SD and median [range]; nonparametric Spearman rank correlations and multiple linear regressions were performed; P-values ≤0.003 were considered significant. RESULTS: Significant correlations (P ≤ 0.003) were found for CFT, α-angle, and MCF, in EXTEM, INTEM, and APTEM with platelets, INR, and fibrinogen. Factor VIII (18 measurements) showed a strong correlation (r ≥ 0.7 or r ≤ -0.7; all P ≤ 0.003) with MCF, CFT, and α-angle of EXTEM, INTEM, MCF of FIBTEM excluding CT of EXTEM, INTEM, FIBTEM and strong significant correlation for α-angle of APTEM and moderate for CFT and MCF of APTEM. A significant moderate to strong correlation of factor XIII with MCF of EXTEM, INTEM, FIBTEM, and APTEM was found. Hemoglobin was moderately correlated (r = 0.3-0.7 or r = -0.3 to -0.7) with MCF in APTEM (P = 0.003). A moderate to strong correlation of the standard coagulation tests with all ROTEM parameters was found, in particular the CT. The aPTT correlated significantly moderate to strong with CT, CFT, α-angle, and MCF of INTEM. However, multiple linear regressions were not able to show an influence of INR on ROTEM parameters except for APTEM-MCF. A significant impact of the aPTT on INTEM-CT was found. EXTEM, INTEM, and APTEM are significantly influenced by fibrinogen and platelets. CONCLUSIONS: The results confirm the clinical assumption that EXTEM, INTEM, and APTEM are associated with fibrinogen and platelets levels; INTEM-CT significantly to aPTT; and FIBTEM significantly to fibrinogen. Factor VIII showed a significant correlation with all ROTEM parameters except CT of EXTEM, INTEM, FIBTEM, and CFT and MCF of APTEM.

Late pharmacologic conditioning with volatile anesthetics after cardiac surgery.

INTRODUCTION: The aim of this randomized controlled trial was to investigate whether volatile anesthetics used for postoperative sedation have any beneficial effects on myocardial injury in cardiac surgery patients after on-pump valve replacement. METHODS: Anesthesia was performed with propofol. After arrival in the intensive care unit (ICU), 117 patients were randomized to be sedated for at least 4 hours with either propofol or sevoflurane. Sevoflurane was administered by using the anesthetic-conserving device. Troponin T, creatine kinase, creatine kinase from heart muscle tissue, myoglobin, and oxygenation index were determined on arrival at the ICU, 4 hours after sedation, and in the morning of the first postoperative day (POD1). Primary end points were cardiac injury markers on POD1. As secondary end points oxygenation, postoperative pulmonary complications, and ICU and hospital stay were documented. RESULTS: Fifty-six patients were analyzed in the propofol arm, and 46 patients in the sevoflurane arm. Treatment groups were comparable with regard to patient demographics and intraoperative characteristics. Concentration of troponin T as the most sensitive marker for myocardial injury at POD1 was significantly lower in the sevoflurane group compared with the propofol group (unadjusted difference, -0.4; 95% CI, -0.7 to -0.1; P < 0.01; adjusted difference, -0.2; 95% CI, -0.4 to -0.02; P = 0.03, respectively). CONCLUSIONS: The data presented in this investigation indicate that late postconditioning with the volatile anesthetic sevoflurane might mediate cardiac protection, even with a late, brief, and low-dose application. TRIAL REGISTRATION: ClinicalTrials.gov: NCT00924222.

Cement-augmented dorsal instrumentation of the spine as a safe adjunct to the multimodal management of metastatic pheochromocytoma: a case report.

Malignant pheochromocytoma is a neuroendocrine tumor that originates from chromaffin tissue. Although osseous metastases are common, metastatic dissemination to the spine rarely occurs.Five years after primary diagnosis of extra-adrenal, abdominal pheochromocytoma and laparoscopic extirpation, a 53-year old patient presented with recurrence of pheochromocytoma involving the spine, the pelvis, both proximal femora and the right humerus. Magnetic resonance imaging and computed tomography revealed osteolytic lesions of numerous vertebrae (T1, T5, T10, and T12). In the case of T10, total destruction of the vertebral body with involvement of the rear edge resulted in the risk of vertebral collapse and subsequent spinal stenosis. Thus, dorsal instrumentation (T8-T12) and cement augmentation of T12 was performed after perioperative alpha- and beta-adrenergic blockade with phenoxybenzamine and bisoprolol.After thorough preoperative evaluation to assess the risk for surgery and anesthesia, and appropriate perioperative management including pharmacological antihypertensive treatment, dorsal instrumentation of T8-T12 and cement augmentation of T12 prior to placing the corresponding pedicle screws did not result in hypertensive crisis or hemodynamic instability due to the release of catecholamines from metastatic lesions.To the authors' knowledge, this is the first report describing cement-augmentation in combination with dorsal instrumentation to prevent osteolytic vertebral collapse in a patient with metastatic pheochromocytoma. With appropriate preoperative measures, cement-augmented dorsal instrumentation represents a safe approach to stabilize vertebral bodies with metastatic malignant pheochromocytoma. Nevertheless, direct manipulation of metastatic lesions should be avoided as far as possible in order to minimize the risk of hemodynamic complications.

Impact of restrictive intravenous fluid replacement and combined epidural analgesia on perioperative volume balance and renal function within a Fast Track program.

BACKGROUND AND OBJECTIVE: Key factors of Fast Track (FT) programs are fluid restriction and epidural analgesia (EDA). We aimed to challenge the preconception that the combination of fluid restriction and EDA might induce hypotension and renal dysfunction. METHODS: A recent randomized trial (NCT00556790) showed reduced complications after colectomy in FT patients compared with standard care (SC). Patients with an effective EDA were compared with regard to hemodynamics and renal function. RESULTS: 61/76 FT patients and 59/75 patients in the SC group had an effective EDA. Both groups were comparable regarding demographics and surgery-related characteristics. FT patients received significantly less i.v. fluids intraoperatively (1900 mL [range 1100-4100] versus 2900 mL [1600-5900], P < 0.0001) and postoperatively (700 mL [400-1500] versus 2300 mL [1800-3800], P < 0.0001). Intraoperatively, 30 FT compared with 19 SC patients needed colloids or vasopressors, but this was statistically not significant (P = 0.066). Postoperative requirements were low in both groups (3 versus 5 patients; P = 0.487). Pre- and postoperative values for creatinine, hematocrit, sodium, and potassium were similar, and no patient developed renal dysfunction in either group. Only one of 82 patients having an EDA without a bladder catheter had urinary retention. Overall, FT patients had fewer postoperative complications (6 versus 20 patients; P = 0.002) and a shorter median hospital stay (5 [2-30] versus 9 d [6-30]; P< 0.0001) compared with the SC group. CONCLUSIONS: Fluid restriction and EDA in FT programs are not associated with clinically relevant hemodynamic instability or renal dysfunction.

Off-pump surgery for the poor ventricle?

Severely decreased ejection-fraction is an established risk-factor for worse outcome after cardiac surgery. We compare outcomes of off-pump coronary artery bypass grafting (OPCAB) and on-pump CABG (ONCABG) in patients with severely compromised EF. From 2004 to 2009, 478 patients with a decreased EF ≤35% underwent myocardial-revascularization. Patients received either OPCAB (n = 256) or ONCABG (n = 222). Propensity score (PS), including 50 preoperative risk-factors, was used to balance characteristics between groups. PS adjusted logistic regression analysis was performed to assess mortality and major adverse cardiac and cerebrovascular events (MACCE). A composite endpoint for major non-cardiac complications such as respiratory failure, renal failure, rethoracotomy was applied. Complete revascularization (CR) was assumed when the number of distal anastomoses was larger than that of diseased vessels. There was no difference for mortality (2.3 vs. 4.1%; PS-adjusted odds ratio (PS-OR) = 1.05; p = 0.93) and MACCE (13.7 vs. 17.6%; PS-OR = 1.22; p = 0.50) including myocardial-infarction (1.4 vs. 4.9%; PS-OR = 0.39; p = 0.26), low cardiac output (2.3 vs. 4.7%; PS-OR = 0.75; p = 0.72) and stroke (2.3 vs. 2.7%; PS-OR = 0.69; p = 0.66). OPCAB patients presented with a trend to less frequent occurrence of the non-cardiac composite (12.1 vs. 22.1%; PS-OR = 0.54; p = 0.059) including renal dysfunction (PAOR = 0.77; 95% CI 0.31-1.9; p = 0.57), bleeding (PAOR = 0.42; 95% CI 0.14-1.20; p = 0.10) and respiratory failure (PAOR = 0.39; 95% CI 0.05-3.29; p = 0.39). The rate of complete revascularization was similar (92.2 vs. 92.8%; PS-OR = 0.75; p = 0.50). OPCAB in patients with severely decreased EF is safe and feasible. It may even benefit these patients in regard to non-cardiac complications and does not come at cost of less complete revascularization.

Hyperfibrinolysis diagnosed by rotational thromboelastometry (ROTEM) is associated with higher mortality in patients with severe trauma.

BACKGROUND: We investigated whether hyperfibrinolysis and its severity was associated with outcome of traumatized and nontraumatized patients. METHODS: From April 2008 to April 2010, all emergency patients with hyperfibrinolysis were enrolled in this study. Hyperfibrinolysis patients were divided into traumatized (trauma hyperfibrinolysis group) and nontraumatized (nontrauma hyperfibrinolysis group). The trauma hyperfibrinolysis group was matched with 24 polytrauma patients without hyperfibrinolysis (matched trauma group). Data from rotational thromboelastometry measurements, blood gas analysis (metabolic state), laboratory analysis, injury severity score, and 30-day mortality were collected. RESULTS: Thirty-five patients with hyperfibrinolysis were identified (13 traumatized, 22 nontraumatized). Overall mortality for hyperfibrinolysis was 54%. Mortality in the trauma hyperfibrinolysis group (77%±12%) was significantly higher than in the nontrauma hyperfibrinolysis group (41%±10%; P=0.001, 95% CI 5%-67%) and the matched trauma group (33%±10%; P=0.009, 95% CI 13%-74%). Hyperfibrinolysis is significantly (P=0.017) associated with mortality in trauma patients. In the blood gas analysis representing the metabolic state, only pH (P=0.02) and potassium (P=0.01) were significantly lower in the trauma hyperfibrinolysis group compared to the nontrauma hyperfibrinolysis group. CONCLUSIONS: Mortality from hyperfibrinolysis is significantly higher in trauma compared with nontrauma patients, and hyperfibrinolysis is an independent factor predicting mortality in trauma patients. Rotational thromboelastometry provides real-time recognition of hyperfibrinolysis allowing early treatment.

Iron core/shell nanoparticles as magnetic drug carriers: possible interactions with the vascular compartment.

AIMS: Nanomagnets with metal cores have recently been shown to be promising candidates for magnetic drug delivery due to higher magnetic moments compared with commonly used metal oxides. Successful application strongly relies on a safe implementation that goes along with detailed knowledge of interactions and effects that nanomagnets might impart once entering the body. MATERIALS & METHODS: In this work, we put a particular focus on the interactions of ultra-strong metal nanomagnets (≥ three-times higher in magnetization compared with oxide nanoparticles) within the vascular compartment. Individual aspects of possible effects are addressed, including interactions with the coagulation cascade, the complement system, phagocytes and toxic or inflammatory reactions both by blood and endothelial cells in response to nanomagnet exposure. RESULTS: We show that carbon-coated metal nanomagnets are well-tolerated by cells of the vascular compartment and have only minor effects on blood coagulation. CONCLUSION: These findings provide the fundament to initiate successful first in vivo evaluations opening metal nanomagnets with improved magnetic properties to fascinating applications in nanomedicine.

A simulated severe difficult airway does not alter the intubation performance with the SensaScope: a prospective randomised manikin study.

DESIGN: Prospective randomised controlled study. SETTING: Operation unit in a tertiary academic university hospital in a central European city. Period of the study was springtime and summer 2010. PATIENTS OR OTHER PARTICIPANTS: Twenty-four anaesthesiologists with various levels of professional experience were allocated to intubate an airway manikin either with the SensaScope (group S) or with the conventional Macintosh 3 laryngoscope (group L). INTERVENTIONS: Each participant performed three consecutive intubations with normal anatomy followed by three intubations with difficult anatomy. The airway difficulty was simulated by inflation of the manikin's tongue base with 40 ml of air. The times taken to view the larynx and to insert the tracheal tube were noted. The resulting tube position and the occurrence of dental damage were recorded. MAIN OUTCOME MEASURES: Those planned in the protocol. RESULTS: In normal anatomy, the laryngeal view (group L 5.9 ± 4.2 s vs. group S 9.2 ± 3.5 s) and intubation (group L 13.4 ± 7.6 s vs. group S 23.3 ± 8.6 s) was more rapidly obtained with conventional laryngoscopy (values presented as mean ± SD). In difficult anatomy, only the SensaScope permitted successful laryngeal view (group L impossible vs. group S 9.9 ± 4.8 s) and tracheal intubation (group L impossible vs. group S 23.4 ± 8.8 s). The latter always enabled correct tracheal tube position, whereas with laryngoscopy alone either oesophageal intubation or aborted attempts resulted. In the difficult airway setting, the frequency of simulated tooth damage was also significantly higher with conventional laryngoscopy (group L 26 of 36 vs. group S 6 of 36). CONCLUSIONS: The SensaScope performed fairly well in normal intubation anatomy, although its use was more complex than with conventional laryngoscopy and it required a slightly longer time. In the difficult airway setting, the SensaScope performed as well as in normal anatomy, whereas intubation by direct laryngoscopy proved to be impossible. The SensaScope enables the user to overcome severe airway difficulties caused by large tissue masses at the level of the tongue base or mouth floor.

Measurement of activated coagulation time in children: evaluation of the blood-saving kaolin i-STAT activated coagulation time technique in pediatric cardiac anesthesia.

OBJECTIVE: To compare the activated coagulation times (ACTs) measured with the blood-saving kaolin i-STAT 1 ACT technique (Abbott Point of Care Inc, Princeton, NJ) with ACTs obtained from the widely used ACTR II device (Medtronic, Inc, Minneapolis, MN) in children undergoing cardiac surgery. DESIGN: A prospective, observational single-center study. PARTICIPANTS: Forty-four pediatric cardiac surgery patients. INTERVENTION: Surgery was performed with cardiopulmonary bypass (CPB) necessitating heparinization. METHODS AND MAIN RESULTS: ACTs measured on the i-STAT 1 device (2 × 95 µL) were compared with those obtained from the Medtronic ACTR II device (2 × 0.5 mL). Blood samples were drawn before, during, and after heparinization for CPB and paired for statistical analysis. The 2 techniques were compared using simple and multiregression analyses and the Bland-Altman method. In total, 179 intrarater and 142 interrater data pairs were analyzed. The intrarater reliability of the 2 devices was good, with a mean bias and limits of agreement of +2.0 and -55.5/+59.5 seconds for the Medtronic ACTR II and +0.5 and -59.9/+60.9 seconds for the i-STAT 1. An interrater reliability analysis of the mean of simultaneously measured ACT of the Medtronic ACTR II and both i-STAT 1 devices yielded a mean bias of -5.3 seconds and limits of agreement of -210.1/+199.5 seconds. A comparison of the higher of the paired ACT values from both devices showed similar results. After the removal of heparin, the i-STAT 1's ACT values became significantly lower than those measured on the Medtronic ACTR II (p < 0.001). Simple and multiregression analyses revealed that base excess independently influenced the mean bias of the ACT values from the Medtronic ACTR II (p = 0.037) and i-STAT 1 devices (p = 0.036). CONCLUSION: The kaolin i-STAT 1 ACT technique agreed well with the Medtronic ACTR II technique during the nonheparinized phase that preceded CPB. The overall agreement between the ACT obtained from the 2 devices was poor. The routine use of i-STAT 1 measured ACT values cannot be recommended as a reliable alternative to the Medtronic ACTR II.

Continuous elastomeric pump-based ropivacaine wound instillation after open abdominal aortic surgery: how reliable is the technique?

INTRODUCTION: We aimed at quantifying the impact of continuous wound infusion with ropivacaine 0.33% on morphine administration and subjective pain relief in patients after open abdominal aortic repair in a double-blind, placebo-controlled study. METHODS: Before closing the abdominal wound, 2 multihole ON-Q® Soaker Catheters™ (I-Flow Corporation, Lake Forest, California, USA) were placed pre-peritoneally in opposite directions. Either ropivacaine 0.33% or saline 0.9% was delivered by an elastomeric pump at a rate of 2 mL/h for 72 hours in each of the catheters. Postoperative pain and morphine administration were assessed using the numerical rating scale (NRS) in 4-hour intervals. Total plasma concentrations of ropivacaine, unbound ropivacaine, and α1-acid glycoprotein (AAG) were measured daily. Mean arterial pressure, pulse rate, oxygen saturation, total amount of morphine administration, ventilation time, and length of stay in the intensive care unit (ICU) were recorded. At the end of the study period, the wound site and the condition of the catheters were assessed. RESULTS: The study was terminated prematurely due to a malfunction of the elastomeric balloon pump resulting in toxic serum levels of total ropivacaine in 2 patients (11.4 µmol/L and 10.0 µmol/L, respectively) on the second postoperative day. Six patients had been allocated to the ropivacaine group, and 9 patients had been allocated to the control group. Demographic and surgical data were similar in both groups. During the first 3 postoperative days, no difference between the ropivacaine and the control group was found in NRS (P = .15, P = .46, and P = .88, respectively) and morphine administration (P = .48). Concentrations of unbound serum ropivacaine (0.11 ± 0.08 µmol/L) were below toxic level in all patients. CONCLUSION: Continuous wound infusion of ropivacaine 0.33% 2 mL/h using an elastomeric system was not reliable and did not improve postoperative pain control in patients after open abdominal aortic surgery.

The revised digital transcutaneous PCO2/SpO2 ear sensor is a reliable noninvasive monitoring tool in patients after cardiac surgery.

OBJECTIVE: The aim of this study was to validate the revised SenTec V-Sign 2 sensor (SenTec AG, Therwil, Switzerland) for combined noninvasive continuous assessment of pulse rate, pulse oximetry (SpO(2)), and transcutaneous carbon dioxide tension (PtcCO(2)) in adults after cardiac surgery. DESIGN: A prospective clinical study. SETTING: A single-center university hospital. PARTICIPANTS: Twenty adult patients aged 36 to 84 years after cardiac surgery. INTERVENTIONS: SpO(2) and PtcCO(2) values of three V-Sign 2 sensors (SenTec AG) attached at the earlobe, forehead, and cheek and SpO(2) values of the Nellcor Durasensor (Model DS-100A; Nellcor Puritan Bennett Inc, Pleasanton, CA) were compared with simultaneous measurements of blood gases and end-expiratory carbon dioxide. MEASUREMENTS AND MAIN RESULTS: Measurements were performed during periods of hyper-, normo-, and hypocapnia and then at 30-minute intervals up to 5 hours. Bland-Altman analysis and simple regression analysis were used. RESULTS: The detection failures for PtcCO(2) were 0.3% to 1.3%, for SpO(2) 10% to 25%, and for pulse rate 5% to 10%. The V-Sign 2 earlobe sensor provided the best results. The mean bias and limits of agreement for PtcCO(2ear) and PaCO(2) were 1.1 and -3.4/+5.5 mmHg. The drift of PtcCO(2) was negligible at all locations. The mean bias and limits of agreement of V-Sign SpO(2ear) and SaO(2), as well as V-Sign pulse rate and the electrocardiogram, were -1.7% and -6.8/+3.9% and 1.2 beats/min and -3.3/+5.8 beats/min. End-expiratory carbon dioxide showed a weak correlation with PaCO(2) (r(2) = 0.47). CONCLUSIONS: Transcutaneous capnometry using the revised V-Sign 2 sensor at the earlobe is a reliable monitoring tool during the recovery period of patients after cardiac surgery. This approach has the potential to reduce the number of arterial blood gas samples.

The PediaSat continuous central SvO2 monitoring system does not reliably indicate state or course of central venous oxygenation.

BACKGROUND AND OBJECTIVE: The present study compares the accuracy of a new continuous venous oxygenation monitoring system (PediaSat Oximetry Catheter) with laboratory blood oximetry in paediatric surgical patients. METHODS: Children and adolescents undergoing cardiac, orthopaedic or craniofacial surgery with major blood loss were included. A 4.5 Fr two-lumen or 5.5 Fr three-lumen central venous oximetry catheter (SPediaSatcvO2) was inserted preoperatively into the superior vena cava. After in-vivo calibration of the PediaSat system, repeated blood samples were obtained from the distal port of the venous catheter and oximetrically analysed for haemoglobin and central venous oxygen saturation (SCO-OXcvO2). Central venous oxygen saturation values measured by the PediaSat (SPediaSatcvO2) were compared with co-oximetry (SCO-OXcvO2) values from the simultaneously taken blood samples by Bland-Altman and simple regression analyses. RESULTS: Overall, 142 data pairs from 27 patients, aged from 0.6 to 19.0 years (median 5.3 years) were analysed. SPediaSatcvO2 and SCO-OXcvO2 values ranged from 57 to 98% and from 57.1 to 95.8%, respectively. Correlation between SPediaSatcvO2 and SCO-OXcvO2 was poor with r equal to 0.28 (P < 0.0001). SPediaSatcvO2 overestimated SCO-OXcvO2 (mean bias +2.6%), but limits of agreement (+/-2 SD of bias) were unacceptably high (-14.4/+19.6%). Sensitivity and specificity of SPediaSatcvO2 to indicate a fall or rise of SCO-OXcvO2 between two subsequent measurements were only 0.42 and 0.24, respectively. CONCLUSION: In paediatric and adolescent patients undergoing major surgery, the PediaSat system did not reliably reflect SCO-OXcvO2 values and cannot replace repeated invasive ScvO2 assessments in the clinically relevant range of ScvO2.