Mid- and Long-Term Outcomes of Total Arterial Myocardial Revascularization in Patients Aged 70 Years and Older: A Single-Center Experience.

BACKGROUND: Patients receiving arterial grafts have superior late survival after coronary artery bypass graft (CABG) surgery. The aim of our study was to evaluate the mid- and long-term results of total arterial (TA) revascularization in the elderly. METHODS: Between January 2005 and December 2012, a retrospective study on age-, gender-, and EuroSCORE-matched patients aged 70 years and older was performed. Altogether, 356 patients who received isolated CABG were assigned to either TA group or control (CON) group. RESULTS: No significant differences were noted in regard to preoperative risk factors. The number of distal anastomoses was significantly higher in the CON group (3.6 ± 0.6 vs. 2.9 ± 0.8; p < 0.001). Postoperatively, no significant differences were noted in regard to morbidity or mortality. There were no significant differences in mortality rate at 1 year (5.6 vs. 5.2%; p = 0.98), or 5 years (9.0 vs. 12.1%; p = 0.39) between both groups. However, the TA group was associated with significantly higher rate of event-free survival (p = 0.017). CONCLUSION: This study suggests that TA revascularization is an effective procedure. Lower rates of late cardiac events encourage the use of this concept for the elderly.

Over Ten Years of Experience with a Modified Right Atrial Anastomosis in Orthotopic Heart Transplantation: Follow-up and Comparison with the Biatrial and Bicaval Technique.

BACKGROUND: In 1997, a modified right atrial anastomosis (cavoatrial technique) for orthotopic heart transplantation (oHTx) was first developed in our institution. The purpose of this study is to report our long-term experience with this technique compared with biatrial and bicaval technique. METHODS: Retrospectively, 202 consecutive oHTx between 1997 and 2013 were analyzed. The applied transplantation techniques were biatrial (n = 108), bicaval (n = 22), and cavoatrial (n = 72). RESULTS: Demographic data were similar in all groups. The cardiopulmonary bypass and cross-clamp time were significantly shorter in the biatrial group. Follow-up echocardiographic examination showed excellent results in all groups with no relevant differences. After 1 year, occurrence of severe tricuspid regurgitation (biatrial 1.9% vs bicaval 0.0% vs cavoatrial 1.4%) was low in all groups. Rate of permanent pacemaker implantations was also low (12.0% vs 5.0% vs 11.1%). There were no significant differences in survival between the groups. CONCLUSION: The cavoatrial technique can be a safe and simple alternative for heart transplantation. Easy handling and similar reduced postoperative complications encourage the use of this technique.

Effects of propofol on wound closure and barrier function of cultured endothelial cells: An in vitro experimental study.

BACKGROUND: Propofol is widely used in routine clinical practice for the induction and maintenance of anaesthesia. Although propofol is regarded as a well tolerated anaesthetic, its effect on intact or damaged endothelial cells has not yet been elucidated. OBJECTIVE: The aim of this study was to investigate the effects of different concentrations of propofol on cell damage, metabolic activity, barrier function and wound healing capacity of human endothelial cells. DESIGN: An in vitro investigation. SETTING: Research Laboratory of the Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Kiel, Germany. MATERIALS: In vitro cultures of primary human umbilical vein endothelial cells (HUVECs). INTERVENTIONS: Intact HUVEC or wounded HUVEC monolayers were incubated with or without different concentrations of propofol (10, 30 and 100 µmol l). MAIN OUTCOME MEASURES: Cell damage, metabolic activity, monolayer permeability, wound healing capacity, protein phosphorylation. RESULTS: Propofol did not alter the morphology, induce cell damage or influence metabolic activity of intact HUVEC cells. Permeability of a HUVEC monolayer was increased by propofol 100 µmol l (P < 0.05). Wound closure was inhibited by the addition of propofol 30 and 100 µmol l (P < 0.05 and P < 0.01). This effect was associated with increased phosphorylation of extracellular signal regulated kinases (Erk) 1/2 (30 and 100 µmol l; both P < 0.05) and decreased phosphorylation of Rho kinase (Rock) (100 µmol l; P < 0.05). CONCLUSION: Propofol does not damage intact endothelial cells, but increases permeability of an endothelial cell monolayer at high concentrations and inhibits wound closure in vitro. Further experimental and clinical in vivo research should be performed to clarify the influence of propofol on endothelial wound healing.

[Cardiac Anaesthesia: Anaesthesiological Management]. / Kardioanästhesie: anästhesiologisches Management.

The anaesthesiological management of patients scheduled for cardiac surgery has been refined distinctively over the last decade due to different reasons. The continuing growth of the elderly patient population and the increasing number of combined cardiac surgery procedures in octogenarians on the one hand are one aspect. The rapid development of minimally invasive cardiac surgery and the enhancements in mechanical, artificial heart assist devices on the other hand can be seen as additional decisive factors. All of these innovations in the field of cardiac surgery implicate further enhancements regarding the anaesthesiological management. This review article addresses the following subareas of cardiac anaesthesia: significance of pharmacological myocardial protection, anaesthetic management during cardiopulmonary bypass, importance of "Enhanced Recovery After Cardiac Surgery"-protocols as well as innovations in the field of minimally invasive cardiac surgery like transcatheter aortic valve implantation.

Effect of Xenon Anesthesia Compared to Sevoflurane and Total Intravenous Anesthesia for Coronary Artery Bypass Graft Surgery on Postoperative Cardiac Troponin Release: An International, Multicenter, Phase 3, Single-blinded, Randomized Noninferiority Trial.

BACKGROUND: Ischemic myocardial damage accompanying coronary artery bypass graft surgery remains a clinical challenge. We investigated whether xenon anesthesia could limit myocardial damage in coronary artery bypass graft surgery patients, as has been reported for animal ischemia models. METHODS: In 17 university hospitals in France, Germany, Italy, and The Netherlands, low-risk elective, on-pump coronary artery bypass graft surgery patients were randomized to receive xenon, sevoflurane, or propofol-based total intravenous anesthesia for anesthesia maintenance. The primary outcome was the cardiac troponin I concentration in the blood 24 h postsurgery. The noninferiority margin for the mean difference in cardiac troponin I release between the xenon and sevoflurane groups was less than 0.15 ng/ml. Secondary outcomes were the safety and feasibility of xenon anesthesia. RESULTS: The first patient included at each center received xenon anesthesia for practical reasons. For all other patients, anesthesia maintenance was randomized (intention-to-treat: n = 492; per-protocol/without major protocol deviation: n = 446). Median 24-h postoperative cardiac troponin I concentrations (ng/ml [interquartile range]) were 1.14 [0.76 to 2.10] with xenon, 1.30 [0.78 to 2.67] with sevoflurane, and 1.48 [0.94 to 2.78] with total intravenous anesthesia [per-protocol]). The mean difference in cardiac troponin I release between xenon and sevoflurane was -0.09 ng/ml (95% CI, -0.30 to 0.11; per-protocol: P = 0.02). Postoperative cardiac troponin I release was significantly less with xenon than with total intravenous anesthesia (intention-to-treat: P = 0.05; per-protocol: P = 0.02). Perioperative variables and postoperative outcomes were comparable across all groups, with no safety concerns. CONCLUSIONS: In postoperative cardiac troponin I release, xenon was noninferior to sevoflurane in low-risk, on-pump coronary artery bypass graft surgery patients. Only with xenon was cardiac troponin I release less than with total intravenous anesthesia. Xenon anesthesia appeared safe and feasible.

Dynamic Variables Fail to Predict Fluid Responsiveness in an Animal Model With Pericardial Effusion.

OBJECTIVES: The reliability of dynamic and volumetric variables of fluid responsiveness in the presence of pericardial effusion is still elusive. The aim of the present study was to investigate their predictive power in a porcine model with hemodynamic relevant pericardial effusion. DESIGN: A single-center animal investigation. PARTICIPANTS: Twelve German domestic pigs. INTERVENTIONS: Pigs were studied before and during pericardial effusion. Instrumentation included a pulmonary artery catheter and a transpulmonary thermodilution catheter in the femoral artery. Hemodynamic variables like cardiac output (COPAC) and stroke volume (SVPAC) derived from pulmonary artery catheter, global end-diastolic volume (GEDV), stroke volume variation (SVV), and pulse-pressure variation (PPV) were obtained. MEASUREMENTS AND MAIN RESULTS: At baseline, SVV, PPV, GEDV, COPAC, and SVPAC reliably predicted fluid responsiveness (area under the curve 0.81 [p = 0.02], 0.82 [p = 0.02], 0.74 [p = 0.07], 0.74 [p = 0.07], 0.82 [p = 0.02]). After establishment of pericardial effusion the predictive power of dynamic variables was impaired and only COPAC and SVPAC and GEDV allowed significant prediction of fluid responsiveness (area under the curve 0.77 [p = 0.04], 0.76 [p = 0.05], 0.83 [p = 0.01]) with clinically relevant changes in threshold values. CONCLUSIONS: In this porcine model, hemodynamic relevant pericardial effusion abolished the ability of dynamic variables to predict fluid responsiveness. COPAC, SVPAC, and GEDV enabled prediction, but their threshold values were significantly changed.

Warming before and after epidural block before general anaesthesia for major abdominal surgery prevents perioperative hypothermia: A randomised controlled trial.

BACKGROUND: Epidural analgesia (EDA) is known to be an independent risk factor for perioperative hypothermia and its many known adverse effects. Combined general and epidural anaesthesia decreases intraoperative core temperature more rapidly than general anaesthesia alone. Hence, adequate warming procedures are needed for these patients. OBJECTIVE: We evaluated the effects of active skin-surface warming before and/or after initiation of EDA during general anaesthesia as a procedure to prevent perioperative hypothermia. DESIGN: A randomised controlled trial. SETTING: Department of Anaesthesiology in a general hospital in Germany from January 2013 until August 2014. PATIENTS: After obtaining written informed consent, we included 99 adult patients undergoing elective major abdominal surgery under combined general anaesthesia and EDA with an expected duration of surgery of at least 120 min. Patients were excluded if they were under 18 years of age, classified as American Society of Anesthesiologists' physical status 4 or higher or if patients refused EDA. INTERVENTIONS: Patients were randomly assigned to one of three groups and received either only passive insulation, 15 min of active air-forced warming after EDA and before induction of general anaesthesia, or two periods, each of 15 min, of active air-forced warming before and after EDA. Core and skin temperatures were measured at several time points throughout the study. MAIN OUTCOME MEASURES: The primary outcome measure was the incidence of hypothermia on arrival in the ICU. The secondary outcome measure was the incidence of postoperative shivering. In addition, the perioperative change in body core temperature was recorded. RESULTS: Without prewarming (n = 32), 72% of patients became hypothermic (<36°C) at the end of anaesthesia. Fifteen minutes of warming after insertion of the epidural catheter and before initiation of general anaesthesia reduced the incidence of postoperative hypothermia to 6% (n = 33). After two periods of 15 min of warming before and after insertion of the epidural catheter, no patient became hypothermic (n = 34). Prewarming in either 'warming' group prevents the initial temperature drop which was observed in the control group. CONCLUSION: Warming for 15 min before and after initiation of EDA in patients receiving combined anaesthesia is effective in preventing postoperative hypothermia. TRIAL REGISTRATION: This trial was registered with ClinicalTrials.gov (identifier: NCT01795482).

Accuracy of an autocalibrated pulse contour analysis in cardiac surgery patients: a bi-center clinical trial.

BACKGROUND: Less-invasive and easy to install monitoring systems for continuous estimation of cardiac index (CI) have gained increasing interest, especially in cardiac surgery patients who often exhibit abrupt haemodynamic changes. The aim of the present study was to compare the accuracy of CI by a new semi-invasive monitoring system with transpulmonary thermodilution before and after cardiopulmonary bypass (CPB). METHODS: Sixty-five patients (41 Germany, 24 Spain) scheduled for elective coronary surgery were studied before and after CPB, respectively. Measurements included CI obtained by transpulmonary thermodilution (CITPTD) and autocalibrated semi-invasive pulse contour analysis (CIPFX). Percentage changes of CI were also calculated. RESULTS: There was only a poor correlation between CITPTD and CIPFX both before (r (2) = 0.34, p < 0.0001) and after (r (2) = 0.31, p < 0.0001) CPB, with a percentage error (PE) of 62 and 49 %, respectively. Four quadrant plots revealed a concordance rate over 90 % indicating an acceptable correlation of trends between CITPTD and CIPFX before (concordance: 93 %) and after (concordance: 94 %) CPB. In contrast, polar plot analysis showed poor trending before and an acceptable trending ability of changes in CI after CPB. CONCLUSIONS: Semi-invasive CI by autocalibrated pulse contour analysis showed a poor ability to estimate CI compared with transpulmonary thermodilution. Furthermore, the new semi-invasive device revealed an acceptable trending ability for haemodynamic changes only after CPB. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02312505 Date: 12.03.2012.

Catch my drift? Between-farm dispersal of biofouling waste from salmon pen net cleaning: Potential risks for fish health.

Biofouling is a serious challenge for global salmon aquaculture and farmers have to regularly clean pen nets to avoid impacts on stock health and farms' structural integrity. The removed material is released into the surrounding environment. This includes cnidarian species such as hydroids, whose nematocyst-bearing fragments can impact gill health and fish welfare. There is also increasing evidence of the association of parasites and pathogens with biofouling organisms and cleaning fragments. It is unknown whether and how far local current regimes disperse biofouling material and whether this material reaches and interacts with adjacent pens or even neighbouring farms downstream, or wild fish populations in surrounding environments. We focussed on the cnidarian hydroid Ectopleura larynx, one of the most abundant biofouling species on Norwegian aquaculture installations. Using a 3D hydrodynamic model parameterised with physical and biological properties of hydroid particles (derived via field and laboratory studies), we simulated the dispersal of net cleaning waste from two Norwegian salmon farms. Our results demonstrate that net cleaning waste is extensively dispersed throughout neighbouring pens, and even to adjacent aquaculture facilities. Salmon were exposed to concentrations of biofouling particles up to 41-fold elevated compared to background concentrations, and for up to 30.5 h. Maximum dispersal distance of hydroid particles was 5.5 km from the point of release, achieved largely within 48 h. Least-cost distance calculations show that this distance exceeds the nearest-neighbour distance of 70 % of Norway's salmon farms (654 farms). Our study provides some evidence that actions taken to manage biofouling at salmon farms may affect neighbouring farms and surrounding natural environments. The results highlight the potential risks associated with net cleaning: the dispersal of harmful cnidarian particles, associated pathogens, and non-indigenous species, thus underlining the need for novel farming or net cleaning technologies that prevent the release of potentially harmful cleaning waste.

Effects of petrogenic pollutants on North Atlantic and Arctic Calanus copepods: From molecular mechanisms to population impacts.

Oil and gas industries in the Northern Atlantic Ocean have gradually moved closer to the Arctic areas, a process expected to be further facilitated by sea ice withdrawal caused by global warming. Copepods of the genus Calanus hold a key position in these cold-water food webs, providing an important energetic link between primary production and higher trophic levels. Due to their ecological importance, there is a concern about how accidental oil spills and produced water discharges may impact cold-water copepods. In this review, we summarize the current knowledge of the toxicity of petroleum on North Atlantic and Arctic Calanus copepods. We also review how recent development of high-quality transcriptomes from RNA-sequencing of copepods have identified genes regulating key biological processes, like molting, diapause and reproduction in Calanus copepods, to suggest linkages between exposure, molecular mechanisms and effects on higher levels of biological organization. We found that the available ecotoxicity threshold data for these copepods provide valuable information about their sensitivity to acute petrogenic exposures; however, there is still insufficient knowledge regarding underlying mechanisms of toxicity and the potential for long-term implications of relevance for copepod ecology and phenology. Copepod transcriptomics has expanded our understanding of how key biological processes are regulated in cold-water copepods. These advances can improve our understanding of how pollutants affect biological processes, and thus provide the basis for new knowledge frameworks spanning the effect continuum from molecular initiating events to adverse effects of regulatory relevance. Such efforts, guided by concepts such as adverse outcome pathways (AOPs), enable standardized and transparent characterization and evaluation of knowledge and identifies research gaps and priorities. This review suggests enhancing mechanistic understanding of exposure-effect relationships to better understand and link biomarker responses to adverse effects to improve risk assessments assessing ecological effects of pollutant mixtures, like crude oil, in Arctic areas.

Remote ischemic preconditioning regulates HIF-1α levels, apoptosis and inflammation in heart tissue of cardiosurgical patients: a pilot experimental study.

Transient episodes of ischemia in a remote organ (remote ischemic preconditioning, RIPC) bears the potential to attenuate myocardial injury, but the underlying mechanisms are only poorly understood. In the pilot experimental study presented we investigated cellular and molecular effects of RIPC in heart tissue of cardiosurgical patients with cardiopulmonary bypass (CPB) and focussed on apoptotic events, local and systemic inflammation as well as the regulation of the hypoxia induced factor-1α (HIF-1α). RIPC was induced by four 5-min cycles of transient upper limb ischemia/reperfusion using a blood-pressure cuff. Right atrial tissue and serum were obtained from patients receiving RIPC (N = 32) and control patients (N = 29) before and after CPB. RIPC patients showed reduced troponin T serum concentrations in the first 48 h after surgery (P < 0.05 vs. control) indicating cardioprotective effects of RIPC. Samples from RIPC patients that were collected before CPB contained significantly increased amounts of HIF-1α and procaspase-3 (HIF-1α: P < 0.05 vs. control, procaspase-3: P < 0.05 vs. control), whereas activities of caspases 3 and 7 were by trend reduced. Samples from RIPC patients that were taken after CPB showed an increased activity of myeloperoxidase (P < 0.05 vs. control; P < 0.05 vs. RIPC before CPB) as well as elevated tissue concentrations of the interleukin (IL)-1ß (P < 0.05 vs. RIPC before CPB). Serum levels of IL-8, IL-1ß and TNFα were significantly increased in RIPC patients before CPB (P < 0.05 vs. control before CPB). In summary, RIPC regulates HIF-1α levels, apoptosis and inflammation in the myocardium of cardiosurgical patients and leads to increased concentrations of circulating cytokines.

Nexfin noninvasive continuous hemodynamic monitoring: validation against continuous pulse contour and intermittent transpulmonary thermodilution derived cardiac output in critically ill patients.

INTRODUCTION: Nexfin (Bmeye, Amsterdam, Netherlands) is a noninvasive cardiac output (CO) monitor based on finger arterial pulse contour analysis. The aim of this study was to validate Nexfin CO (NexCO) against thermodilution (TDCO) and pulse contour CO (CCO) by PiCCO (Pulsion Medical Systems, Munich, Germany). PATIENTS AND METHODS: In a mix of critically ill patients (n = 45), NexCO and CCO were measured continuously and recorded at 2-hour intervals during the 8-hour study period. TDCO was measured at 0-4-8 hrs. RESULTS: NexCO showed a moderate to good (significant) correlation with TDCO (R (2) 0.68, P < 0.001) and CCO (R (2) 0.71, P < 0.001). Bland and Altman analysis comparing NexCO with TDCO revealed a bias (± limits of agreement, LA) of 0.4 ± 2.32 L/min (with 36% error) while analysis comparing NexCO with CCO showed a bias (±LA) of 0.2 ± 2.32 L/min (37% error). NexCO is able to follow changes in TDCO and CCO during the same time interval (level of concordance 89.3% and 81%). Finally, polar plot analysis showed that trending capabilities were acceptable when changes in NexCO (ΔNexCO) were compared to ΔTDCO and ΔCCO (resp., 89% and 88.9% of changes were within the level of 10% limits of agreement). CONCLUSION: we found a moderate to good correlation between CO measurements obtained with Nexfin and PiCCO.

A comparison of third-generation semi-invasive arterial waveform analysis with thermodilution in patients undergoing coronary surgery.

Uncalibrated semi-invasive continous monitoring of cardiac index (CI) has recently gained increasing interest. The aim of the present study was to compare the accuracy of CI determination based on arterial waveform analysis with transpulmonary thermodilution. Fifty patients scheduled for elective coronary surgery were studied after induction of anaesthesia and before and after cardiopulmonary bypass (CPB), respectively. Each patient was monitored with a central venous line, the PiCCO system, and the FloTrac/Vigileo-system. Measurements included CI derived by transpulmonary thermodilution and uncalibrated semi-invasive pulse contour analysis. Percentage changes of CI were calculated. There was a moderate, but significant correlation between pulse contour CI and thermodilution CI both before (r(2) = 0.72, P < 0.0001) and after (r(2) = 0.62, P < 0.0001) CPB, with a percentage error of 31% and 25%, respectively. Changes in pulse contour CI showed a significant correlation with changes in thermodilution CI both before (r(2) = 0.52, P < 0.0001) and after (r(2) = 0.67, P < 0.0001) CPB. Our findings demonstrated that uncalibrated semi-invasive monitoring system was able to reliably measure CI compared with transpulmonary thermodilution in patients undergoing elective coronary surgery. Furthermore, the semi-invasive monitoring device was able to track haemodynamic changes and trends.

Impact of an interleukin-1 receptor antagonist and erythropoietin on experimental myocardial ischemia/reperfusion injury.

BACKGROUND: Revascularization of infarcted myocardium results in release of inflammatory cytokines mediating myocardial reperfusion injury and heart failure. Blockage of inflammatory pathways dampens myocardial injury and reduces infarct size. We compared the impact of the interleukin-1 receptor antagonist Anakinra and erythropoietin on myocardial ischemia/reperfusion injury. In contrast to others, we hypothesized that drug administration prior to reperfusion reduces myocardial damage. METHODS AND RESULTS: 12-15 week-old Lewis rats were subjected to myocardial ischemia by a 1 hr occlusion of the left anterior descending coronary artery. After 15 min of ischemia, a single shot of Anakinra (2 mg/kg body weight (bw)) or erythropoietin (5000 IE/kg bw) was administered intravenously. In contrast to erythropoietin, Anakinra decreased infarct size (P < 0.05, N = 4/group) and troponin T levels (P < 0.05, N = 4/group). CONCLUSION: One-time intravenous administration of Anakinra prior to myocardial reperfusion reduces infarct size in experimental ischemia/reperfusion injury. Thus, Anakinra may represent a treatment option in myocardial infarction prior to revascularization.

[Fluid management: estimation of fluid status]. / Perioperatives Flüssigkeitsmanagement - Abschätzung des Volumenstatus.

Cardiac filling pressures alone are not appropriate to estimate the effect of a volume challenge on the corresponding change in stroke volume. Dynamic variables of fluid responsiveness have been shown to discriminate with acceptable sensitivity and specificity between responders and non-responders to a volume challenge. However, several clinical confounders have been indentified which potentially influence the predictive power of these variables. Sound knowledge of these confounders and the acknowledgement that there is no unique threshold value for volume optimisation but a considerable "gray zone" is necessary to fully exploit the advantages of functional haemodynamic monitoring.

[Fluid management: goal-directed therapy]. / Perioperatives Flüssigkeitsmanagement - Zielgerichtete Therapie.

Goal-directed fluid therapy (GDT) is one important step in perioperative therapy as it improves complication rate and mortality by optimisation of oxygen delivery. There is a convincing evidence for GDT when used early, before organ failure occurs, and in high-risk patients. Moderne algorithms use goals derived from advanced haemodynamic monitoring and are based on the concept of fluid responsiveness and optimisation of global perfusion. Future investigations will have to prove the advantage of using the new less or non-invasive haemodynamic monitoring devices or automatic closed-loop fluid administration systems for GDT.

An annual profile of the impacts of simulated oil spills on the Northeast Arctic cod and haddock fisheries.

We simulate the combined natural and pollutant-induced survival of early life stages of NEA cod and haddock, and the impact on the adult populations in response to the time of a major oil spill in a single year. Our simulations reveal how dynamic ocean processes, controlling both oil transport and fate and the frequency of interactions of oil with drifting fish eggs and larvae, mediate the magnitude of population losses due to an oil spill. The largest impacts on fish early life stages occurred for spills initiated in Feb-Mar, concomitant with the initial rise in marine productivity and the earliest phase of the spawning season. The reproductive health of the adult fish populations was maintained in all scenarios. The study demonstrates the application of a simulation system that provides managers with information for the planning of development activities and for the protection of fisheries resources from potential impacts.

Uncalibrated pulse power analysis fails to reliably measure cardiac output in patients undergoing coronary artery bypass surgery.

INTRODUCTION: Uncalibrated arterial pulse power analysis has been recently introduced for continuous monitoring of cardiac index (CI). The aim of the present study was to compare the accuracy of arterial pulse power analysis with intermittent transpulmonary thermodilution (TPTD) before and after cardiopulmonary bypass (CPB). METHODS: Forty-two patients scheduled for elective coronary surgery were studied after induction of anaesthesia, before and after CPB respectively. Each patient was monitored with the pulse contour cardiac output (PiCCO) system, a central venous line and the recently introduced LiDCO monitoring system. Haemodynamic variables included measurement of CI derived by transpulmonary thermodilution (CITPTD) or CI derived by pulse power analysis (CIPP), before and after calibration (CIPPnon-cal., CIPPcal.). Percentage changes of CI (ΔCITPTD, ΔCIPPnon-cal./PPcal.) were calculated to analyse directional changes. RESULTS: Before CPB there was no significant correlation between CIPPnon-cal. and CITPTD (r2 = 0.04, P = 0.08) with a percentage error (PE) of 86%. Higher mean arterial pressure (MAP) values were significantly correlated with higher CIPPnon-cal. (r2 = 0.26, P < 0.0001). After CPB, CIPPcal. revealed a significant correlation compared with CITPTD (r2 = 0.77, P < 0.0001) with PE of 28%. Changes in CIPPcal. (ΔCIPPcal.) showed a correlation with changes in CITPTD (ΔCITPTD) only after CPB (r2 = 0.52, P = 0.005). CONCLUSIONS: Uncalibrated pulse power analysis was significantly influenced by MAP and was not able to reliably measure CI compared with TPTD. Calibration improved accuracy, but pulse power analysis was still not consistently interchangeable with TPTD. Only calibrated pulse power analysis was able to reliably track haemodynamic changes and trends.

Effect of norepinephrine dosage and calibration frequency on accuracy of pulse contour-derived cardiac output.

INTRODUCTION: Continuous cardiac output monitoring is used for early detection of hemodynamic instability and guidance of therapy in critically ill patients. Recently, the accuracy of pulse contour-derived cardiac output (PCCO) has been questioned in different clinical situations. In this study, we examined agreement between PCCO and transcardiopulmonary thermodilution cardiac output (COTCP) in critically ill patients, with special emphasis on norepinephrine (NE) administration and the time interval between calibrations. METHODS: This prospective, observational study was performed with a sample of 73 patients (mean age, 63 ± 13 years) requiring invasive hemodynamic monitoring on a non-cardiac surgery intensive care unit. PCCO was recorded immediately before calibration by COTCP. Bland-Altman analysis was performed on data subsets comparing agreement between PCCO and COTCP according to NE dosage and the time interval between calibrations up to 24 hours. Further, central artery stiffness was calculated on the basis of the pulse pressure to stroke volume relationship. RESULTS: A total of 330 data pairs were analyzed. For all data pairs, the mean COTCP (±SD) was 8.2 ± 2.0 L/min. PCCO had a mean bias of 0.16 L/min with limits of agreement of -2.81 to 3.15 L/min (percentage error, 38%) when compared to COTCP. Whereas the bias between PCCO and COTCP was not significantly different between NE dosage categories or categories of time elapsed between calibrations, interchangeability (percentage error <30%) between methods was present only in the high NE dosage subgroup (≥0.1 µg/kg/min), as the percentage errors were 40%, 47% and 28% in the no NE, NE < 0.1 and NE ≥ 0.1 µg/kg/min subgroups, respectively. PCCO was not interchangeable with COTCP in subgroups of different calibration intervals. The high NE dosage group showed significantly increased central artery stiffness. CONCLUSIONS: This study shows that NE dosage, but not the time interval between calibrations, has an impact on the agreement between PCCO and COTCP. Only in the measurements with high NE dosage (representing the minority of measurements) was PCCO interchangeable with COTCP.